From 41e2df1bdee527eccdc4622ef2013201afc8e2cc Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Tue, 29 Oct 2019 10:28:55 -0700 Subject: Support iterating an NDP options buffer. This change helps support iterating over an NDP options buffer so that implementations can handle all the NDP options present in an NDP packet. Note, this change does not yet actually handle these options, it just provides the tools to do so (in preparation for NDP's Prefix, Parameter, and a complete implementation of Neighbor Discovery). Tests: Unittests to make sure we can iterate over a valid NDP options buffer that may contain multiple options. Also tests to check an iterator before using it to see if the NDP options buffer is malformed. PiperOrigin-RevId: 277312487 --- pkg/tcpip/header/ndp_options.go | 163 +++++++++++++++++++++++++++++++++++----- 1 file changed, 145 insertions(+), 18 deletions(-) (limited to 'pkg/tcpip/header/ndp_options.go') diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go index 98310ea23..a2b9d7435 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -16,6 +16,7 @@ package header import ( "encoding/binary" + "errors" "time" "gvisor.dev/gvisor/pkg/tcpip" @@ -30,9 +31,9 @@ const ( // Link Layer Option for an Ethernet address. ndpTargetEthernetLinkLayerAddressSize = 8 - // ndpPrefixInformationType is the type of the Prefix Information + // NDPPrefixInformationType is the type of the Prefix Information // option, as per RFC 4861 section 4.6.2. - ndpPrefixInformationType = 3 + NDPPrefixInformationType = 3 // ndpPrefixInformationLength is the expected length, in bytes, of the // body of an NDP Prefix Information option, as per RFC 4861 section @@ -95,9 +96,122 @@ const ( lengthByteUnits = 8 ) +// NDPOptionIterator is an iterator of NDPOption. +// +// Note, between when an NDPOptionIterator is obtained and last used, no changes +// to the NDPOptions may happen. Doing so may cause undefined and unexpected +// behaviour. It is fine to obtain an NDPOptionIterator, iterate over the first +// few NDPOption then modify the backing NDPOptions so long as the +// NDPOptionIterator obtained before modification is no longer used. +type NDPOptionIterator struct { + // The NDPOptions this NDPOptionIterator is iterating over. + opts NDPOptions +} + +// Potential errors when iterating over an NDPOptions. +var ( + ErrNDPOptBufExhausted = errors.New("Buffer unexpectedly exhausted") + ErrNDPOptZeroLength = errors.New("NDP option has zero-valued Length field") + ErrNDPOptMalformedBody = errors.New("NDP option has a malformed body") +) + +// Next returns the next element in the backing NDPOptions, or true if we are +// done, or false if an error occured. +// +// The return can be read as option, done, error. Note, option should only be +// used if done is false and error is nil. +func (i *NDPOptionIterator) Next() (NDPOption, bool, error) { + for { + // Do we still have elements to look at? + if len(i.opts) == 0 { + return nil, true, nil + } + + // Do we have enough bytes for an NDP option that has a Length + // field of at least 1? Note, 0 in the Length field is invalid. + if len(i.opts) < lengthByteUnits { + return nil, true, ErrNDPOptBufExhausted + } + + // Get the Type field. + t := i.opts[0] + + // Get the Length field. + l := i.opts[1] + + // This would indicate an erroneous NDP option as the Length + // field should never be 0. + if l == 0 { + return nil, true, ErrNDPOptZeroLength + } + + // How many bytes are in the option body? + numBytes := int(l) * lengthByteUnits + numBodyBytes := numBytes - 2 + + potentialBody := i.opts[2:] + + // This would indicate an erroenous NDPOptions buffer as we ran + // out of the buffer in the middle of an NDP option. + if left := len(potentialBody); left < numBodyBytes { + return nil, true, ErrNDPOptBufExhausted + } + + // Get only the options body, leaving the rest of the options + // buffer alone. + body := potentialBody[:numBodyBytes] + + // Update opts with the remaining options body. + i.opts = i.opts[numBytes:] + + switch t { + case NDPTargetLinkLayerAddressOptionType: + return NDPTargetLinkLayerAddressOption(body), false, nil + + case NDPPrefixInformationType: + // Make sure the length of a Prefix Information option + // body is ndpPrefixInformationLength, as per RFC 4861 + // section 4.6.2. + if numBodyBytes != ndpPrefixInformationLength { + return nil, true, ErrNDPOptMalformedBody + } + + return NDPPrefixInformation(body), false, nil + default: + // We do not yet recognize the option, just skip for + // now. This is okay because RFC 4861 allows us to + // skip/ignore any unrecognized options. However, + // we MUST recognized all the options in RFC 4861. + // + // TODO(b/141487990): Handle all NDP options as defined + // by RFC 4861. + } + } +} + // NDPOptions is a buffer of NDP options as defined by RFC 4861 section 4.6. type NDPOptions []byte +// Iter returns an iterator of NDPOption. +// +// If check is true, Iter will do an integrity check on the options by iterating +// over it and returning an error if detected. +// +// See NDPOptionIterator for more information. +func (b NDPOptions) Iter(check bool) (NDPOptionIterator, error) { + it := NDPOptionIterator{opts: b} + + if check { + for it2 := it; true; { + if _, done, err := it2.Next(); err != nil || done { + return it, err + } + } + } + + return it, nil +} + // Serialize serializes the provided list of NDP options into o. // // Note, b must be of sufficient size to hold all the options in s. See @@ -137,15 +251,15 @@ func (b NDPOptions) Serialize(s NDPOptionsSerializer) int { return done } -// ndpOption is the set of functions to be implemented by all NDP option types. -type ndpOption interface { - // Type returns the type of this ndpOption. +// NDPOption is the set of functions to be implemented by all NDP option types. +type NDPOption interface { + // Type returns the type of the receiver. Type() uint8 - // Length returns the length of the body of this ndpOption, in bytes. + // Length returns the length of the body of the receiver, in bytes. Length() int - // serializeInto serializes this ndpOption into the provided byte + // serializeInto serializes the receiver into the provided byte // buffer. // // Note, the caller MUST provide a byte buffer with size of at least @@ -154,15 +268,15 @@ type ndpOption interface { // buffer is not of sufficient size. // // serializeInto will return the number of bytes that was used to - // serialize this ndpOption. Implementers must only use the number of - // bytes required to serialize this ndpOption. Callers MAY provide a + // serialize the receiver. Implementers must only use the number of + // bytes required to serialize the receiver. Callers MAY provide a // larger buffer than required to serialize into. serializeInto([]byte) int } // paddedLength returns the length of o, in bytes, with any padding bytes, if // required. -func paddedLength(o ndpOption) int { +func paddedLength(o NDPOption) int { l := o.Length() if l == 0 { @@ -201,7 +315,7 @@ func paddedLength(o ndpOption) int { } // NDPOptionsSerializer is a serializer for NDP options. -type NDPOptionsSerializer []ndpOption +type NDPOptionsSerializer []NDPOption // Length returns the total number of bytes required to serialize. func (b NDPOptionsSerializer) Length() int { @@ -221,21 +335,34 @@ func (b NDPOptionsSerializer) Length() int { // where X is the value in Length multiplied by lengthByteUnits - 2 bytes. type NDPTargetLinkLayerAddressOption tcpip.LinkAddress -// Type implements ndpOption.Type. +// Type implements NDPOption.Type. func (o NDPTargetLinkLayerAddressOption) Type() uint8 { return NDPTargetLinkLayerAddressOptionType } -// Length implements ndpOption.Length. +// Length implements NDPOption.Length. func (o NDPTargetLinkLayerAddressOption) Length() int { return len(o) } -// serializeInto implements ndpOption.serializeInto. +// serializeInto implements NDPOption.serializeInto. func (o NDPTargetLinkLayerAddressOption) serializeInto(b []byte) int { return copy(b, o) } +// EthernetAddress will return an ethernet (MAC) address if the +// NDPTargetLinkLayerAddressOption's body has at minimum EthernetAddressSize +// bytes. If the body has more than EthernetAddressSize bytes, only the first +// EthernetAddressSize bytes are returned as that is all that is needed for an +// Ethernet address. +func (o NDPTargetLinkLayerAddressOption) EthernetAddress() tcpip.LinkAddress { + if len(o) >= EthernetAddressSize { + return tcpip.LinkAddress(o[:EthernetAddressSize]) + } + + return tcpip.LinkAddress([]byte(nil)) +} + // NDPPrefixInformation is the NDP Prefix Information option as defined by // RFC 4861 section 4.6.2. // @@ -243,17 +370,17 @@ func (o NDPTargetLinkLayerAddressOption) serializeInto(b []byte) int { // ndpPrefixInformationLength bytes. type NDPPrefixInformation []byte -// Type implements ndpOption.Type. +// Type implements NDPOption.Type. func (o NDPPrefixInformation) Type() uint8 { - return ndpPrefixInformationType + return NDPPrefixInformationType } -// Length implements ndpOption.Length. +// Length implements NDPOption.Length. func (o NDPPrefixInformation) Length() int { return ndpPrefixInformationLength } -// serializeInto implements ndpOption.serializeInto. +// serializeInto implements NDPOption.serializeInto. func (o NDPPrefixInformation) serializeInto(b []byte) int { used := copy(b, o) -- cgit v1.2.3 From 5398530e45634b6f5ea4344d1a34b41cc8123457 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Tue, 12 Nov 2019 14:02:53 -0800 Subject: Discover on-link prefixes from Router Advertisements' Prefix Information options This change allows the netstack to do NDP's Prefix Discovery as outlined by RFC 4861 section 6.3.4. If configured to do so, when a new on-link prefix is discovered, the routing table will be updated with a device route through the nic the RA arrived at. Likewise, when such a prefix gets invalidated, the device route will be removed. Note, this change will not break existing uses of netstack as the default configuration for the stack options is set in such a way that Prefix Discovery will not be performed. See `stack.Options` and `stack.NDPConfigurations` for more details. This change reuses 1 option and introduces a new one that is required to take advantage of Prefix Discovery, all available under NDPConfigurations: - HandleRAs: Whether or not NDP RAs are processes - DiscoverOnLinkPrefixes: Whether or not Prefix Discovery is performed (new) Another note: for a NIC to process Prefix Information options (in Router Advertisements), it must not be a router itself. Currently the netstack does not have per-interface routing configuration; the routing/forwarding configuration is controlled stack-wide. Therefore, if the stack is configured to enable forwarding/routing, no router Advertisements (and by extension the Prefix Information options) will be processed. Tests: Unittest to make sure that Prefix Discovery and updates to the routing table only occur if explicitly configured to do so. Unittest to make sure at max stack.MaxDiscoveredOnLinkPrefixes discovered on-link prefixes are remembered. PiperOrigin-RevId: 280049278 --- pkg/tcpip/header/ndp_options.go | 25 +- pkg/tcpip/stack/ndp.go | 309 +++++++++++++++++++++-- pkg/tcpip/stack/ndp_test.go | 534 +++++++++++++++++++++++++++++++++++++++- pkg/tcpip/stack/nic.go | 1 + 4 files changed, 836 insertions(+), 33 deletions(-) (limited to 'pkg/tcpip/header/ndp_options.go') diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go index a2b9d7435..1ca6199ef 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -85,17 +85,22 @@ const ( // within an NDPPrefixInformation. ndpPrefixInformationPrefixOffset = 14 - // NDPPrefixInformationInfiniteLifetime is a value that represents - // infinity for the Valid and Preferred Lifetime fields in a NDP Prefix - // Information option. Its value is (2^32 - 1)s = 4294967295s - NDPPrefixInformationInfiniteLifetime = time.Second * 4294967295 - // lengthByteUnits is the multiplier factor for the Length field of an // NDP option. That is, the length field for NDP options is in units of // 8 octets, as per RFC 4861 section 4.6. lengthByteUnits = 8 ) +var ( + // NDPPrefixInformationInfiniteLifetime is a value that represents + // infinity for the Valid and Preferred Lifetime fields in a NDP Prefix + // Information option. Its value is (2^32 - 1)s = 4294967295s + // + // This is a variable instead of a constant so that tests can change + // this value to a smaller value. It should only be modified by tests. + NDPPrefixInformationInfiniteLifetime = time.Second * 4294967295 +) + // NDPOptionIterator is an iterator of NDPOption. // // Note, between when an NDPOptionIterator is obtained and last used, no changes @@ -461,3 +466,13 @@ func (o NDPPrefixInformation) PreferredLifetime() time.Duration { func (o NDPPrefixInformation) Prefix() tcpip.Address { return tcpip.Address(o[ndpPrefixInformationPrefixOffset:][:IPv6AddressSize]) } + +// Subnet returns the Prefix field and Prefix Length field represented in a +// tcpip.Subnet. +func (o NDPPrefixInformation) Subnet() tcpip.Subnet { + addrWithPrefix := tcpip.AddressWithPrefix{ + Address: o.Prefix(), + PrefixLen: int(o.PrefixLength()), + } + return addrWithPrefix.Subnet() +} diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index 8e49f7a56..8357dca77 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -46,11 +46,18 @@ const ( // defaultDiscoverDefaultRouters is the default configuration for // whether or not to discover default routers from incoming Router - // Advertisements as a host. + // Advertisements, as a host. // // Default = true. defaultDiscoverDefaultRouters = true + // defaultDiscoverOnLinkPrefixes is the default configuration for + // whether or not to discover on-link prefixes from incoming Router + // Advertisements' Prefix Information option, as a host. + // + // Default = true. + defaultDiscoverOnLinkPrefixes = true + // minimumRetransmitTimer is the minimum amount of time to wait between // sending NDP Neighbor solicitation messages. Note, RFC 4861 does // not impose a minimum Retransmit Timer, but we do here to make sure @@ -72,6 +79,14 @@ const ( // // Max = 10. MaxDiscoveredDefaultRouters = 10 + + // MaxDiscoveredOnLinkPrefixes is the maximum number of discovered + // on-link prefixes. The stack should stop discovering new on-link + // prefixes after discovering MaxDiscoveredOnLinkPrefixes on-link + // prefixes. + // + // Max = 10. + MaxDiscoveredOnLinkPrefixes = 10 ) // NDPDispatcher is the interface integrators of netstack must implement to @@ -106,6 +121,24 @@ type NDPDispatcher interface { // This function is not permitted to block indefinitely. This function // is also not permitted to call into the stack. OnDefaultRouterInvalidated(nicID tcpip.NICID, addr tcpip.Address) []tcpip.Route + + // OnOnLinkPrefixDiscovered will be called when a new on-link prefix is + // discovered. Implementations must return true along with a new valid + // route table if the newly discovered on-link prefix should be + // remembered. If an implementation returns false, the second return + // value will be ignored. + // + // This function is not permitted to block indefinitely. This function + // is also not permitted to call into the stack. + OnOnLinkPrefixDiscovered(nicID tcpip.NICID, prefix tcpip.Subnet) (bool, []tcpip.Route) + + // OnOnLinkPrefixInvalidated will be called when a discovered on-link + // prefix is invalidated. Implementers must return a new valid route + // table. + // + // This function is not permitted to block indefinitely. This function + // is also not permitted to call into the stack. + OnOnLinkPrefixInvalidated(nicID tcpip.NICID, prefix tcpip.Subnet) []tcpip.Route } // NDPConfigurations is the NDP configurations for the netstack. @@ -130,6 +163,11 @@ type NDPConfigurations struct { // be discovered from Router Advertisements. This configuration is // ignored if HandleRAs is false. DiscoverDefaultRouters bool + + // DiscoverOnLinkPrefixes determines whether or not on-link prefixes + // will be discovered from Router Advertisements' Prefix Information + // option. This configuration is ignored if HandleRAs is false. + DiscoverOnLinkPrefixes bool } // DefaultNDPConfigurations returns an NDPConfigurations populated with @@ -140,6 +178,7 @@ func DefaultNDPConfigurations() NDPConfigurations { RetransmitTimer: defaultRetransmitTimer, HandleRAs: defaultHandleRAs, DiscoverDefaultRouters: defaultDiscoverDefaultRouters, + DiscoverOnLinkPrefixes: defaultDiscoverOnLinkPrefixes, } } @@ -167,6 +206,10 @@ type ndpState struct { // The default routers discovered through Router Advertisements. defaultRouters map[tcpip.Address]defaultRouterState + + // The on-link prefixes discovered through Router Advertisements' Prefix + // Information option. + onLinkPrefixes map[tcpip.Subnet]onLinkPrefixState } // dadState holds the Duplicate Address Detection timer and channel to signal @@ -183,11 +226,11 @@ type dadState struct { } // defaultRouterState holds data associated with a default router discovered by -// a Router Advertisement. +// a Router Advertisement (RA). type defaultRouterState struct { invalidationTimer *time.Timer - // Used to signal the timer not to invalidate the default router (R) in + // Used to inform the timer not to invalidate the default router (R) in // a race condition (T1 is a goroutine that handles an RA from R and T2 // is the goroutine that handles R's invalidation timer firing): // T1: Receive a new RA from R @@ -198,10 +241,33 @@ type defaultRouterState struct { // T2: Obtains NIC's lock & invalidates R immediately // // To resolve this, T1 will check to see if the timer already fired, and - // signal the timer using this channel to not invalidate R, so that once - // T2 obtains the lock, it will see that there is an event on this - // channel and do nothing further. - doNotInvalidateC chan struct{} + // inform the timer using doNotInvalidate to not invalidate R, so that + // once T2 obtains the lock, it will see that it is set to true and do + // nothing further. + doNotInvalidate *bool +} + +// onLinkPrefixState holds data associated with an on-link prefix discovered by +// a Router Advertisement's Prefix Information option (PI) when the NDP +// configurations was configured to do so. +type onLinkPrefixState struct { + invalidationTimer *time.Timer + + // Used to signal the timer not to invalidate the on-link prefix (P) in + // a race condition (T1 is a goroutine that handles a PI for P and T2 + // is the goroutine that handles P's invalidation timer firing): + // T1: Receive a new PI for P + // T1: Obtain the NIC's lock before processing the PI + // T2: P's invalidation timer fires, and gets blocked on obtaining the + // NIC's lock + // T1: Refreshes/extends P's lifetime & releases NIC's lock + // T2: Obtains NIC's lock & invalidates P immediately + // + // To resolve this, T1 will check to see if the timer already fired, and + // inform the timer using doNotInvalidate to not invalidate P, so that + // once T2 obtains the lock, it will see that it is set to true and do + // nothing further. + doNotInvalidate *bool } // startDuplicateAddressDetection performs Duplicate Address Detection. @@ -440,14 +506,13 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { if !timer.Stop() { // If we reach this point, then we know the // timer fired after we already took the NIC - // lock. Signal the timer so that once it - // obtains the lock, it doesn't actually - // invalidate the router as we just got a new - // RA that refreshes its lifetime to a non-zero - // value. See - // defaultRouterState.doNotInvalidateC for more + // lock. Inform the timer not to invalidate the + // router when it obtains the lock as we just + // got a new RA that refreshes its lifetime to a + // non-zero value. See + // defaultRouterState.doNotInvalidate for more // details. - rtr.doNotInvalidateC <- struct{}{} + *rtr.doNotInvalidate = true } timer.Reset(rl) @@ -459,8 +524,117 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { } } - // TODO(b/140948104): Do Prefix Discovery. - // TODO(b/141556115): Do Parameter Discovery. + // TODO(b/141556115): Do (RetransTimer, ReachableTime)) Parameter + // Discovery. + + // We know the options is valid as far as wire format is concerned since + // we got the Router Advertisement, as documented by this fn. Given this + // we do not check the iterator for errors on calls to Next. + it, _ := ra.Options().Iter(false) + for opt, done, _ := it.Next(); !done; opt, done, _ = it.Next() { + switch opt.Type() { + case header.NDPPrefixInformationType: + if !ndp.configs.DiscoverOnLinkPrefixes { + continue + } + + pi := opt.(header.NDPPrefixInformation) + + prefix := pi.Subnet() + + // Is the prefix a link-local? + if header.IsV6LinkLocalAddress(prefix.ID()) { + // ...Yes, skip as per RFC 4861 section 6.3.4. + continue + } + + // Is the Prefix Length 0? + if prefix.Prefix() == 0 { + // ...Yes, skip as this is an invalid prefix + // as all IPv6 addresses cannot be on-link. + continue + } + + if !pi.OnLinkFlag() { + // Not on-link so don't "discover" it as an + // on-link prefix. + continue + } + + prefixState, ok := ndp.onLinkPrefixes[prefix] + vl := pi.ValidLifetime() + switch { + case !ok && vl == 0: + // Don't know about this prefix but has a zero + // valid lifetime, so just ignore. + continue + + case !ok && vl != 0: + // This is a new on-link prefix we are + // discovering. + // + // Only remember it if we currently know about + // less than MaxDiscoveredOnLinkPrefixes on-link + // prefixes. + if len(ndp.onLinkPrefixes) < MaxDiscoveredOnLinkPrefixes { + ndp.rememberOnLinkPrefix(prefix, vl) + } + continue + + case ok && vl == 0: + // We know about the on-link prefix, but it is + // no longer to be considered on-link, so + // invalidate it. + ndp.invalidateOnLinkPrefix(prefix) + continue + } + + // This is an already discovered on-link prefix with a + // new non-zero valid lifetime. + // Update the invalidation timer. + timer := prefixState.invalidationTimer + + if timer == nil && vl >= header.NDPPrefixInformationInfiniteLifetime { + // Had infinite valid lifetime before and + // continues to have an invalid lifetime. Do + // nothing further. + continue + } + + if timer != nil && !timer.Stop() { + // If we reach this point, then we know the + // timer already fired after we took the NIC + // lock. Inform the timer to not invalidate + // the prefix once it obtains the lock as we + // just got a new PI that refeshes its lifetime + // to a non-zero value. See + // onLinkPrefixState.doNotInvalidate for more + // details. + *prefixState.doNotInvalidate = true + } + + if vl >= header.NDPPrefixInformationInfiniteLifetime { + // Prefix is now valid forever so we don't need + // an invalidation timer. + prefixState.invalidationTimer = nil + ndp.onLinkPrefixes[prefix] = prefixState + continue + } + + if timer != nil { + // We already have a timer so just reset it to + // expire after the new valid lifetime. + timer.Reset(vl) + continue + } + + // We do not have a timer so just create a new one. + prefixState.invalidationTimer = ndp.prefixInvalidationCallback(prefix, vl, prefixState.doNotInvalidate) + ndp.onLinkPrefixes[prefix] = prefixState + } + + // TODO(b/141556115): Do (MTU) Parameter Discovery. + } } // invalidateDefaultRouter invalidates a discovered default router. @@ -477,8 +651,8 @@ func (ndp *ndpState) invalidateDefaultRouter(ip tcpip.Address) { rtr.invalidationTimer.Stop() rtr.invalidationTimer = nil - close(rtr.doNotInvalidateC) - rtr.doNotInvalidateC = nil + *rtr.doNotInvalidate = true + rtr.doNotInvalidate = nil delete(ndp.defaultRouters, ip) @@ -508,9 +682,9 @@ func (ndp *ndpState) rememberDefaultRouter(ip tcpip.Address, rl time.Duration) { } // Used to signal the timer not to invalidate the default router (R) in - // a race condition. See defaultRouterState.doNotInvalidateC for more + // a race condition. See defaultRouterState.doNotInvalidate for more // details. - doNotInvalidateC := make(chan struct{}, 1) + var doNotInvalidate bool ndp.defaultRouters[ip] = defaultRouterState{ invalidationTimer: time.AfterFunc(rl, func() { @@ -519,16 +693,103 @@ func (ndp *ndpState) rememberDefaultRouter(ip tcpip.Address, rl time.Duration) { ndp.nic.mu.Lock() defer ndp.nic.mu.Unlock() - select { - case <-doNotInvalidateC: + if doNotInvalidate { + doNotInvalidate = false return - default: } ndp.invalidateDefaultRouter(ip) }), - doNotInvalidateC: doNotInvalidateC, + doNotInvalidate: &doNotInvalidate, + } + + ndp.nic.stack.routeTable = routeTable +} + +// rememberOnLinkPrefix remembers a newly discovered on-link prefix with IPv6 +// address with prefix prefix with lifetime l. +// +// The prefix identified by prefix MUST NOT already be known. +// +// The NIC that ndp belongs to and its associated stack MUST be locked. +func (ndp *ndpState) rememberOnLinkPrefix(prefix tcpip.Subnet, l time.Duration) { + if ndp.nic.stack.ndpDisp == nil { + return + } + + // Inform the integrator when we discovered an on-link prefix. + remember, routeTable := ndp.nic.stack.ndpDisp.OnOnLinkPrefixDiscovered(ndp.nic.ID(), prefix) + if !remember { + // Informed by the integrator to not remember the prefix, do + // nothing further. + return + } + + // Used to signal the timer not to invalidate the on-link prefix (P) in + // a race condition. See onLinkPrefixState.doNotInvalidate for more + // details. + var doNotInvalidate bool + var timer *time.Timer + + // Only create a timer if the lifetime is not infinite. + if l < header.NDPPrefixInformationInfiniteLifetime { + timer = ndp.prefixInvalidationCallback(prefix, l, &doNotInvalidate) + } + + ndp.onLinkPrefixes[prefix] = onLinkPrefixState{ + invalidationTimer: timer, + doNotInvalidate: &doNotInvalidate, } ndp.nic.stack.routeTable = routeTable } + +// invalidateOnLinkPrefix invalidates a discovered on-link prefix. +// +// The NIC that ndp belongs to and its associated stack MUST be locked. +func (ndp *ndpState) invalidateOnLinkPrefix(prefix tcpip.Subnet) { + s, ok := ndp.onLinkPrefixes[prefix] + + // Is the on-link prefix still discovered? + if !ok { + // ...Nope, do nothing further. + return + } + + if s.invalidationTimer != nil { + s.invalidationTimer.Stop() + s.invalidationTimer = nil + *s.doNotInvalidate = true + } + + s.doNotInvalidate = nil + + delete(ndp.onLinkPrefixes, prefix) + + // Let the integrator know a discovered on-link prefix is invalidated. + if ndp.nic.stack.ndpDisp != nil { + ndp.nic.stack.routeTable = ndp.nic.stack.ndpDisp.OnOnLinkPrefixInvalidated(ndp.nic.ID(), prefix) + } +} + +// prefixInvalidationCallback returns a new on-link prefix invalidation timer +// for prefix that fires after vl. +// +// doNotInvalidate is used to signal the timer when it fires at the same time +// that a prefix's valid lifetime gets refreshed. See +// onLinkPrefixState.doNotInvalidate for more details. +func (ndp *ndpState) prefixInvalidationCallback(prefix tcpip.Subnet, vl time.Duration, doNotInvalidate *bool) *time.Timer { + return time.AfterFunc(vl, func() { + ndp.nic.stack.mu.Lock() + defer ndp.nic.stack.mu.Unlock() + ndp.nic.mu.Lock() + defer ndp.nic.mu.Unlock() + + if *doNotInvalidate { + *doNotInvalidate = false + return + } + + ndp.invalidateOnLinkPrefix(prefix) + }) +} diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go index 50ce1bbfa..494244368 100644 --- a/pkg/tcpip/stack/ndp_test.go +++ b/pkg/tcpip/stack/ndp_test.go @@ -96,6 +96,13 @@ type ndpRouterEvent struct { discovered bool } +type ndpPrefixEvent struct { + nicID tcpip.NICID + prefix tcpip.Subnet + // true if prefix was discovered, false if invalidated. + discovered bool +} + var _ stack.NDPDispatcher = (*ndpDispatcher)(nil) // ndpDispatcher implements NDPDispatcher so tests can know when various NDP @@ -104,6 +111,8 @@ type ndpDispatcher struct { dadC chan ndpDADEvent routerC chan ndpRouterEvent rememberRouter bool + prefixC chan ndpPrefixEvent + rememberPrefix bool routeTable []tcpip.Route } @@ -169,6 +178,54 @@ func (n *ndpDispatcher) OnDefaultRouterInvalidated(nicID tcpip.NICID, addr tcpip return rt } +// Implements stack.NDPDispatcher.OnOnLinkPrefixDiscovered. +func (n *ndpDispatcher) OnOnLinkPrefixDiscovered(nicID tcpip.NICID, prefix tcpip.Subnet) (bool, []tcpip.Route) { + if n.prefixC != nil { + n.prefixC <- ndpPrefixEvent{ + nicID, + prefix, + true, + } + } + + if !n.rememberPrefix { + return false, nil + } + + rt := append([]tcpip.Route(nil), n.routeTable...) + rt = append(rt, tcpip.Route{ + Destination: prefix, + NIC: nicID, + }) + n.routeTable = rt + return true, rt +} + +// Implements stack.NDPDispatcher.OnOnLinkPrefixInvalidated. +func (n *ndpDispatcher) OnOnLinkPrefixInvalidated(nicID tcpip.NICID, prefix tcpip.Subnet) []tcpip.Route { + if n.prefixC != nil { + n.prefixC <- ndpPrefixEvent{ + nicID, + prefix, + false, + } + } + + rt := make([]tcpip.Route, 0) + exclude := tcpip.Route{ + Destination: prefix, + NIC: nicID, + } + + for _, r := range n.routeTable { + if r != exclude { + rt = append(rt, r) + } + } + n.routeTable = rt + return rt +} + // TestDADResolve tests that an address successfully resolves after performing // DAD for various values of DupAddrDetectTransmits and RetransmitTimer. // Included in the subtests is a test to make sure that an invalid @@ -682,16 +739,19 @@ func TestSetNDPConfigurations(t *testing.T) { } } -// raBuf returns a valid NDP Router Advertisement. +// raBufWithOpts returns a valid NDP Router Advertisement with options. // -// Note, raBuf does not populate any of the RA fields other than the +// Note, raBufWithOpts does not populate any of the RA fields other than the // Router Lifetime. -func raBuf(ip tcpip.Address, rl uint16) tcpip.PacketBuffer { - icmpSize := header.ICMPv6HeaderSize + header.NDPRAMinimumSize +func raBufWithOpts(ip tcpip.Address, rl uint16, optSer header.NDPOptionsSerializer) tcpip.PacketBuffer { + icmpSize := header.ICMPv6HeaderSize + header.NDPRAMinimumSize + int(optSer.Length()) hdr := buffer.NewPrependable(header.IPv6MinimumSize + icmpSize) pkt := header.ICMPv6(hdr.Prepend(icmpSize)) pkt.SetType(header.ICMPv6RouterAdvert) pkt.SetCode(0) + ra := header.NDPRouterAdvert(pkt.NDPPayload()) + opts := ra.Options() + opts.Serialize(optSer) // Populate the Router Lifetime. binary.BigEndian.PutUint16(pkt.NDPPayload()[2:], rl) pkt.SetChecksum(header.ICMPv6Checksum(pkt, ip, header.IPv6AllNodesMulticastAddress, buffer.VectorisedView{})) @@ -708,6 +768,35 @@ func raBuf(ip tcpip.Address, rl uint16) tcpip.PacketBuffer { return tcpip.PacketBuffer{Data: hdr.View().ToVectorisedView()} } +// raBuf returns a valid NDP Router Advertisement. +// +// Note, raBuf does not populate any of the RA fields other than the +// Router Lifetime. +func raBuf(ip tcpip.Address, rl uint16) tcpip.PacketBuffer { + return raBufWithOpts(ip, rl, header.NDPOptionsSerializer{}) +} + +// raBufWithPI returns a valid NDP Router Advertisement with a single Prefix +// Information option. +// +// Note, raBufWithPI does not populate any of the RA fields other than the +// Router Lifetime. +func raBufWithPI(ip tcpip.Address, rl uint16, prefix tcpip.AddressWithPrefix, onLink bool, vl uint32) tcpip.PacketBuffer { + flags := uint8(0) + if onLink { + flags |= 128 + } + + buf := [30]byte{} + buf[0] = uint8(prefix.PrefixLen) + buf[1] = flags + binary.BigEndian.PutUint32(buf[2:], vl) + copy(buf[14:], prefix.Address) + return raBufWithOpts(ip, rl, header.NDPOptionsSerializer{ + header.NDPPrefixInformation(buf[:]), + }) +} + // TestNoRouterDiscovery tests that router discovery will not be performed if // configured not to. func TestNoRouterDiscovery(t *testing.T) { @@ -1011,3 +1100,440 @@ func TestRouterDiscoveryMaxRouters(t *testing.T) { t.Fatalf("got GetRouteTable = %v, want = %v", got, expectedRt) } } + +// TestNoPrefixDiscovery tests that prefix discovery will not be performed if +// configured not to. +func TestNoPrefixDiscovery(t *testing.T) { + prefix := tcpip.AddressWithPrefix{ + Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x08\x00\x00\x00\x00\x00\x00\x00\x00"), + PrefixLen: 64, + } + + // Being configured to discover prefixes means handle and + // discover are set to true and forwarding is set to false. + // This tests all possible combinations of the configurations, + // except for the configuration where handle = true, discover = + // true and forwarding = false (the required configuration to do + // prefix discovery) - that will done in other tests. + for i := 0; i < 7; i++ { + handle := i&1 != 0 + discover := i&2 != 0 + forwarding := i&4 == 0 + + t.Run(fmt.Sprintf("HandleRAs(%t), DiscoverOnLinkPrefixes(%t), Forwarding(%t)", handle, discover, forwarding), func(t *testing.T) { + ndpDisp := ndpDispatcher{ + prefixC: make(chan ndpPrefixEvent, 10), + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: handle, + DiscoverOnLinkPrefixes: discover, + }, + NDPDisp: &ndpDisp, + }) + s.SetForwarding(forwarding) + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Rx an RA with prefix with non-zero lifetime. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, 10)) + + select { + case <-ndpDisp.prefixC: + t.Fatal("unexpectedly discovered a prefix when configured not to") + case <-time.After(defaultTimeout): + } + }) + } +} + +// TestPrefixDiscoveryDispatcherNoRemember tests that the stack does not +// remember a discovered on-link prefix when the dispatcher asks it not to. +func TestPrefixDiscoveryDispatcherNoRemember(t *testing.T) { + prefix := tcpip.AddressWithPrefix{ + Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x08\x00\x00\x00\x00\x00\x00\x00\x00"), + PrefixLen: 64, + } + subnet := prefix.Subnet() + + ndpDisp := ndpDispatcher{ + prefixC: make(chan ndpPrefixEvent, 10), + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + DiscoverDefaultRouters: false, + DiscoverOnLinkPrefixes: true, + }, + NDPDisp: &ndpDisp, + }) + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + routeTable := []tcpip.Route{ + { + header.IPv6EmptySubnet, + llAddr3, + 1, + }, + } + s.SetRouteTable(routeTable) + + // Rx an RA with prefix with a short lifetime. + const lifetime = 1 + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, lifetime)) + select { + case r := <-ndpDisp.prefixC: + if r.nicID != 1 { + t.Fatalf("got r.nicID = %d, want = 1", r.nicID) + } + if r.prefix != subnet { + t.Fatalf("got r.prefix = %s, want = %s", r.prefix, subnet) + } + if !r.discovered { + t.Fatal("got r.discovered = false, want = true") + } + case <-time.After(defaultTimeout): + t.Fatal("timeout waiting for prefix discovery event") + } + + // Original route table should not have been modified. + if got := s.GetRouteTable(); !cmp.Equal(got, routeTable) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, routeTable) + } + + // Wait for the normal invalidation time plus some buffer to + // make sure we do not actually receive any invalidation events as + // we should not have remembered the prefix in the first place. + select { + case <-ndpDisp.prefixC: + t.Fatal("should not have received any prefix events") + case <-time.After(lifetime*time.Second + defaultTimeout): + } + + // Original route table should not have been modified. + if got := s.GetRouteTable(); !cmp.Equal(got, routeTable) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, routeTable) + } +} + +func TestPrefixDiscovery(t *testing.T) { + prefix1 := tcpip.AddressWithPrefix{ + Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x08\x00\x00\x00\x00\x00\x00\x00\x00"), + PrefixLen: 64, + } + prefix2 := tcpip.AddressWithPrefix{ + Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x09\x00\x00\x00\x00\x00\x00\x00\x00"), + PrefixLen: 64, + } + prefix3 := tcpip.AddressWithPrefix{ + Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x09\x0a\x00\x00\x00\x00\x00\x00\x00"), + PrefixLen: 72, + } + subnet1 := prefix1.Subnet() + subnet2 := prefix2.Subnet() + subnet3 := prefix3.Subnet() + + ndpDisp := ndpDispatcher{ + prefixC: make(chan ndpPrefixEvent, 10), + rememberPrefix: true, + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + DiscoverOnLinkPrefixes: true, + }, + NDPDisp: &ndpDisp, + }) + + waitForEvent := func(subnet tcpip.Subnet, discovered bool, timeout time.Duration) { + t.Helper() + + select { + case r := <-ndpDisp.prefixC: + if r.nicID != 1 { + t.Fatalf("got r.nicID = %d, want = 1", r.nicID) + } + if r.prefix != subnet { + t.Fatalf("got r.prefix = %s, want = %s", r.prefix, subnet) + } + if r.discovered != discovered { + t.Fatalf("got r.discovered = %t, want = %t", r.discovered, discovered) + } + case <-time.After(timeout): + t.Fatal("timeout waiting for prefix discovery event") + } + } + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Receive an RA with prefix1 in an NDP Prefix Information option (PI) + // with zero valid lifetime. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, 0)) + select { + case <-ndpDisp.prefixC: + t.Fatal("unexpectedly discovered a prefix with 0 lifetime") + case <-time.After(defaultTimeout): + } + + // Receive an RA with prefix1 in an NDP Prefix Information option (PI) + // with non-zero lifetime. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, 100)) + waitForEvent(subnet1, true, defaultTimeout) + + // Should have added a device route for subnet1 through the nic. + if got, want := s.GetRouteTable(), []tcpip.Route{{subnet1, tcpip.Address([]byte(nil)), 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Receive an RA with prefix2 in a PI. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix2, true, 100)) + waitForEvent(subnet2, true, defaultTimeout) + + // Should have added a device route for subnet2 through the nic. + if got, want := s.GetRouteTable(), []tcpip.Route{{subnet1, tcpip.Address([]byte(nil)), 1}, {subnet2, tcpip.Address([]byte(nil)), 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Receive an RA with prefix3 in a PI. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix3, true, 100)) + waitForEvent(subnet3, true, defaultTimeout) + + // Should have added a device route for subnet3 through the nic. + if got, want := s.GetRouteTable(), []tcpip.Route{{subnet1, tcpip.Address([]byte(nil)), 1}, {subnet2, tcpip.Address([]byte(nil)), 1}, {subnet3, tcpip.Address([]byte(nil)), 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Receive an RA with prefix1 in a PI with lifetime = 0. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, 0)) + waitForEvent(subnet1, false, defaultTimeout) + + // Should have removed the device route for subnet1 through the nic. + if got, want := s.GetRouteTable(), []tcpip.Route{{subnet2, tcpip.Address([]byte(nil)), 1}, {subnet3, tcpip.Address([]byte(nil)), 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Receive an RA with prefix2 in a PI with lesser lifetime. + lifetime := uint32(2) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix2, true, lifetime)) + select { + case <-ndpDisp.prefixC: + t.Fatal("unexpectedly received prefix event when updating lifetime") + case <-time.After(defaultTimeout): + } + + // Should not have updated route table. + if got, want := s.GetRouteTable(), []tcpip.Route{{subnet2, tcpip.Address([]byte(nil)), 1}, {subnet3, tcpip.Address([]byte(nil)), 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Wait for prefix2's most recent invalidation timer plus some buffer to + // expire. + waitForEvent(subnet2, false, time.Duration(lifetime)*time.Second+defaultTimeout) + + // Should have removed the device route for subnet2 through the nic. + if got, want := s.GetRouteTable(), []tcpip.Route{{subnet3, tcpip.Address([]byte(nil)), 1}}; !cmp.Equal(got, want) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, want) + } + + // Receive RA to invalidate prefix3. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix3, true, 0)) + waitForEvent(subnet3, false, defaultTimeout) + + // Should not have any routes. + if got := len(s.GetRouteTable()); got != 0 { + t.Fatalf("got len(s.GetRouteTable()) = %d, want = 0", got) + } +} + +func TestPrefixDiscoveryWithInfiniteLifetime(t *testing.T) { + // Update the infinite lifetime value to a smaller value so we can test + // that when we receive a PI with such a lifetime value, we do not + // invalidate the prefix. + const testInfiniteLifetimeSeconds = 2 + const testInfiniteLifetime = testInfiniteLifetimeSeconds * time.Second + saved := header.NDPPrefixInformationInfiniteLifetime + header.NDPPrefixInformationInfiniteLifetime = testInfiniteLifetime + defer func() { + header.NDPPrefixInformationInfiniteLifetime = saved + }() + + prefix := tcpip.AddressWithPrefix{ + Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x08\x00\x00\x00\x00\x00\x00\x00\x00"), + PrefixLen: 64, + } + subnet := prefix.Subnet() + + ndpDisp := ndpDispatcher{ + prefixC: make(chan ndpPrefixEvent, 10), + rememberPrefix: true, + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + DiscoverOnLinkPrefixes: true, + }, + NDPDisp: &ndpDisp, + }) + + waitForEvent := func(discovered bool, timeout time.Duration) { + t.Helper() + + select { + case r := <-ndpDisp.prefixC: + if r.nicID != 1 { + t.Errorf("got r.nicID = %d, want = 1", r.nicID) + } + if r.prefix != subnet { + t.Errorf("got r.prefix = %s, want = %s", r.prefix, subnet) + } + if r.discovered != discovered { + t.Errorf("got r.discovered = %t, want = %t", r.discovered, discovered) + } + case <-time.After(timeout): + t.Fatal("timeout waiting for prefix discovery event") + } + } + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Receive an RA with prefix in an NDP Prefix Information option (PI) + // with infinite valid lifetime which should not get invalidated. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, testInfiniteLifetimeSeconds)) + waitForEvent(true, defaultTimeout) + select { + case <-ndpDisp.prefixC: + t.Fatal("unexpectedly invalidated a prefix with infinite lifetime") + case <-time.After(testInfiniteLifetime + defaultTimeout): + } + + // Receive an RA with finite lifetime. + // The prefix should get invalidated after 1s. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, testInfiniteLifetimeSeconds-1)) + waitForEvent(false, testInfiniteLifetime) + + // Receive an RA with finite lifetime. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, testInfiniteLifetimeSeconds-1)) + waitForEvent(true, defaultTimeout) + + // Receive an RA with prefix with an infinite lifetime. + // The prefix should not be invalidated. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, testInfiniteLifetimeSeconds)) + select { + case <-ndpDisp.prefixC: + t.Fatal("unexpectedly invalidated a prefix with infinite lifetime") + case <-time.After(testInfiniteLifetime + defaultTimeout): + } + + // Receive an RA with a prefix with a lifetime value greater than the + // set infinite lifetime value. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, testInfiniteLifetimeSeconds+1)) + select { + case <-ndpDisp.prefixC: + t.Fatal("unexpectedly invalidated a prefix with infinite lifetime") + case <-time.After((testInfiniteLifetimeSeconds+1)*time.Second + defaultTimeout): + } + + // Receive an RA with 0 lifetime. + // The prefix should get invalidated. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, 0)) + waitForEvent(false, defaultTimeout) +} + +// TestPrefixDiscoveryMaxRouters tests that only +// stack.MaxDiscoveredOnLinkPrefixes discovered on-link prefixes are remembered. +func TestPrefixDiscoveryMaxOnLinkPrefixes(t *testing.T) { + ndpDisp := ndpDispatcher{ + prefixC: make(chan ndpPrefixEvent, stack.MaxDiscoveredOnLinkPrefixes+3), + rememberPrefix: true, + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + DiscoverDefaultRouters: false, + DiscoverOnLinkPrefixes: true, + }, + NDPDisp: &ndpDisp, + }) + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + optSer := make(header.NDPOptionsSerializer, stack.MaxDiscoveredOnLinkPrefixes+2) + expectedRt := [stack.MaxDiscoveredOnLinkPrefixes]tcpip.Route{} + prefixes := [stack.MaxDiscoveredOnLinkPrefixes + 2]tcpip.Subnet{} + + // Receive an RA with 2 more than the max number of discovered on-link + // prefixes. + for i := 0; i < stack.MaxDiscoveredOnLinkPrefixes+2; i++ { + prefixAddr := [16]byte{1, 2, 3, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0, 0, 0} + prefixAddr[7] = byte(i) + prefix := tcpip.AddressWithPrefix{ + Address: tcpip.Address(prefixAddr[:]), + PrefixLen: 64, + } + prefixes[i] = prefix.Subnet() + buf := [30]byte{} + buf[0] = uint8(prefix.PrefixLen) + buf[1] = 128 + binary.BigEndian.PutUint32(buf[2:], 10) + copy(buf[14:], prefix.Address) + + optSer[i] = header.NDPPrefixInformation(buf[:]) + + if i < stack.MaxDiscoveredOnLinkPrefixes { + expectedRt[i] = tcpip.Route{prefixes[i], tcpip.Address([]byte(nil)), 1} + } + } + + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithOpts(llAddr1, 0, optSer)) + for i := 0; i < stack.MaxDiscoveredOnLinkPrefixes+2; i++ { + if i < stack.MaxDiscoveredOnLinkPrefixes { + select { + case r := <-ndpDisp.prefixC: + if r.nicID != 1 { + t.Fatalf("got r.nicID = %d, want = 1", r.nicID) + } + if r.prefix != prefixes[i] { + t.Fatalf("got r.prefix = %s, want = %s", r.prefix, prefixes[i]) + } + if !r.discovered { + t.Fatal("got r.discovered = false, want = true") + } + case <-time.After(defaultTimeout): + t.Fatal("timeout waiting for prefix discovery event") + } + } else { + select { + case <-ndpDisp.prefixC: + t.Fatal("should not have discovered a new prefix after we already discovered the max number of prefixes") + case <-time.After(defaultTimeout): + } + } + } + + // Should only have device routes for the first + // stack.MaxDiscoveredOnLinkPrefixes discovered on-link prefixes. + if got := s.GetRouteTable(); !cmp.Equal(got, expectedRt[:]) { + t.Fatalf("got GetRouteTable = %v, want = %v", got, expectedRt) + } +} diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index 28a28ae6e..9ed9e1e7c 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -118,6 +118,7 @@ func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, loopback configs: stack.ndpConfigs, dad: make(map[tcpip.Address]dadState), defaultRouters: make(map[tcpip.Address]defaultRouterState), + onLinkPrefixes: make(map[tcpip.Subnet]onLinkPrefixState), }, } nic.ndp.nic = nic -- cgit v1.2.3 From 10f7b109ab98c95783357b82e1934586f338c2b3 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Thu, 5 Dec 2019 10:40:18 -0800 Subject: Add a type to represent the NDP Recursive DNS Server option This change adds a type to represent the NDP Recursive DNS Server option, as defined by RFC 8106 section 5.1. PiperOrigin-RevId: 284005493 --- pkg/tcpip/header/BUILD | 5 +- pkg/tcpip/header/ndp_options.go | 118 +++++++++++++++++++++- pkg/tcpip/header/ndp_test.go | 215 ++++++++++++++++++++++++++++++++++++++++ pkg/tcpip/stack/ndp.go | 6 +- pkg/tcpip/stack/ndp_test.go | 6 +- 5 files changed, 339 insertions(+), 11 deletions(-) (limited to 'pkg/tcpip/header/ndp_options.go') diff --git a/pkg/tcpip/header/BUILD b/pkg/tcpip/header/BUILD index a3485b35c..8392cb9e5 100644 --- a/pkg/tcpip/header/BUILD +++ b/pkg/tcpip/header/BUILD @@ -55,5 +55,8 @@ go_test( "ndp_test.go", ], embed = [":header"], - deps = ["//pkg/tcpip"], + deps = [ + "//pkg/tcpip", + "@com_github_google_go-cmp//cmp:go_default_library", + ], ) diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go index 1ca6199ef..2652e7b67 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -85,6 +85,23 @@ const ( // within an NDPPrefixInformation. ndpPrefixInformationPrefixOffset = 14 + // NDPRecursiveDNSServerOptionType is the type of the Recursive DNS + // Server option, as per RFC 8106 section 5.1. + NDPRecursiveDNSServerOptionType = 25 + + // ndpRecursiveDNSServerLifetimeOffset is the start of the 4-byte + // Lifetime field within an NDPRecursiveDNSServer. + ndpRecursiveDNSServerLifetimeOffset = 2 + + // ndpRecursiveDNSServerAddressesOffset is the start of the addresses + // for IPv6 Recursive DNS Servers within an NDPRecursiveDNSServer. + ndpRecursiveDNSServerAddressesOffset = 6 + + // minNDPRecursiveDNSServerLength is the minimum NDP Recursive DNS + // Server option's length field value when it contains at least one + // IPv6 address. + minNDPRecursiveDNSServerLength = 3 + // lengthByteUnits is the multiplier factor for the Length field of an // NDP option. That is, the length field for NDP options is in units of // 8 octets, as per RFC 4861 section 4.6. @@ -92,13 +109,13 @@ const ( ) var ( - // NDPPrefixInformationInfiniteLifetime is a value that represents + // NDPInfiniteLifetime is a value that represents // infinity for the Valid and Preferred Lifetime fields in a NDP Prefix // Information option. Its value is (2^32 - 1)s = 4294967295s // // This is a variable instead of a constant so that tests can change // this value to a smaller value. It should only be modified by tests. - NDPPrefixInformationInfiniteLifetime = time.Second * 4294967295 + NDPInfiniteLifetime = time.Second * 4294967295 ) // NDPOptionIterator is an iterator of NDPOption. @@ -118,6 +135,7 @@ var ( ErrNDPOptBufExhausted = errors.New("Buffer unexpectedly exhausted") ErrNDPOptZeroLength = errors.New("NDP option has zero-valued Length field") ErrNDPOptMalformedBody = errors.New("NDP option has a malformed body") + ErrNDPInvalidLength = errors.New("NDP option's Length value is invalid as per relevant RFC") ) // Next returns the next element in the backing NDPOptions, or true if we are @@ -182,6 +200,22 @@ func (i *NDPOptionIterator) Next() (NDPOption, bool, error) { } return NDPPrefixInformation(body), false, nil + + case NDPRecursiveDNSServerOptionType: + // RFC 8106 section 5.3.1 outlines that the RDNSS option + // must have a minimum length of 3 so it contains at + // least one IPv6 address. + if l < minNDPRecursiveDNSServerLength { + return nil, true, ErrNDPInvalidLength + } + + opt := NDPRecursiveDNSServer(body) + if len(opt.Addresses()) == 0 { + return nil, true, ErrNDPOptMalformedBody + } + + return opt, false, nil + default: // We do not yet recognize the option, just skip for // now. This is okay because RFC 4861 allows us to @@ -434,7 +468,7 @@ func (o NDPPrefixInformation) AutonomousAddressConfigurationFlag() bool { // // Note, a value of 0 implies the prefix should not be considered as on-link, // and a value of infinity/forever is represented by -// NDPPrefixInformationInfiniteLifetime. +// NDPInfiniteLifetime. func (o NDPPrefixInformation) ValidLifetime() time.Duration { // The field is the time in seconds, as per RFC 4861 section 4.6.2. return time.Second * time.Duration(binary.BigEndian.Uint32(o[ndpPrefixInformationValidLifetimeOffset:])) @@ -447,7 +481,7 @@ func (o NDPPrefixInformation) ValidLifetime() time.Duration { // // Note, a value of 0 implies that addresses generated from the prefix should // no longer remain preferred, and a value of infinity is represented by -// NDPPrefixInformationInfiniteLifetime. +// NDPInfiniteLifetime. // // Also note that the value of this field MUST NOT exceed the Valid Lifetime // field to avoid preferring addresses that are no longer valid, for the @@ -476,3 +510,79 @@ func (o NDPPrefixInformation) Subnet() tcpip.Subnet { } return addrWithPrefix.Subnet() } + +// NDPRecursiveDNSServer is the NDP Recursive DNS Server option, as defined by +// RFC 8106 section 5.1. +// +// To make sure that the option meets its minimum length and does not end in the +// middle of a DNS server's IPv6 address, the length of a valid +// NDPRecursiveDNSServer must meet the following constraint: +// (Length - ndpRecursiveDNSServerAddressesOffset) % IPv6AddressSize == 0 +type NDPRecursiveDNSServer []byte + +// Type returns the type of an NDP Recursive DNS Server option. +// +// Type implements NDPOption.Type. +func (NDPRecursiveDNSServer) Type() uint8 { + return NDPRecursiveDNSServerOptionType +} + +// Length implements NDPOption.Length. +func (o NDPRecursiveDNSServer) Length() int { + return len(o) +} + +// serializeInto implements NDPOption.serializeInto. +func (o NDPRecursiveDNSServer) serializeInto(b []byte) int { + used := copy(b, o) + + // Zero out the reserved bytes that are before the Lifetime field. + for i := 0; i < ndpRecursiveDNSServerLifetimeOffset; i++ { + b[i] = 0 + } + + return used +} + +// Lifetime returns the length of time that the DNS server addresses +// in this option may be used for name resolution. +// +// Note, a value of 0 implies the addresses should no longer be used, +// and a value of infinity/forever is represented by NDPInfiniteLifetime. +// +// Lifetime may panic if o does not have enough bytes to hold the Lifetime +// field. +func (o NDPRecursiveDNSServer) Lifetime() time.Duration { + // The field is the time in seconds, as per RFC 8106 section 5.1. + return time.Second * time.Duration(binary.BigEndian.Uint32(o[ndpRecursiveDNSServerLifetimeOffset:])) +} + +// Addresses returns the recursive DNS server IPv6 addresses that may be +// used for name resolution. +// +// Note, some of the addresses returned MAY be link-local addresses. +// +// Addresses may panic if o does not hold valid IPv6 addresses. +func (o NDPRecursiveDNSServer) Addresses() []tcpip.Address { + l := len(o) + if l < ndpRecursiveDNSServerAddressesOffset { + return nil + } + + l -= ndpRecursiveDNSServerAddressesOffset + if l%IPv6AddressSize != 0 { + return nil + } + + buf := o[ndpRecursiveDNSServerAddressesOffset:] + var addrs []tcpip.Address + for len(buf) > 0 { + addr := tcpip.Address(buf[:IPv6AddressSize]) + if !IsV6UnicastAddress(addr) { + return nil + } + addrs = append(addrs, addr) + buf = buf[IPv6AddressSize:] + } + return addrs +} diff --git a/pkg/tcpip/header/ndp_test.go b/pkg/tcpip/header/ndp_test.go index ad6daafcd..2c439d70c 100644 --- a/pkg/tcpip/header/ndp_test.go +++ b/pkg/tcpip/header/ndp_test.go @@ -19,6 +19,7 @@ import ( "testing" "time" + "github.com/google/go-cmp/cmp" "gvisor.dev/gvisor/pkg/tcpip" ) @@ -369,6 +370,175 @@ func TestNDPPrefixInformationOption(t *testing.T) { } } +func TestNDPRecursiveDNSServerOptionSerialize(t *testing.T) { + b := []byte{ + 9, 8, + 1, 2, 4, 8, + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, + } + targetBuf := []byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1} + expected := []byte{ + 25, 3, 0, 0, + 1, 2, 4, 8, + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, + } + opts := NDPOptions(targetBuf) + serializer := NDPOptionsSerializer{ + NDPRecursiveDNSServer(b), + } + if got, want := opts.Serialize(serializer), len(expected); got != want { + t.Errorf("got Serialize = %d, want = %d", got, want) + } + if !bytes.Equal(targetBuf, expected) { + t.Fatalf("got targetBuf = %x, want = %x", targetBuf, expected) + } + + it, err := opts.Iter(true) + if err != nil { + t.Fatalf("got Iter = (_, %s), want = (_, nil)", err) + } + + next, done, err := it.Next() + if err != nil { + t.Fatalf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if done { + t.Fatal("got Next = (_, true, _), want = (_, false, _)") + } + if got := next.Type(); got != NDPRecursiveDNSServerOptionType { + t.Errorf("got Type = %d, want = %d", got, NDPRecursiveDNSServerOptionType) + } + + opt, ok := next.(NDPRecursiveDNSServer) + if !ok { + t.Fatalf("next (type = %T) cannot be casted to an NDPRecursiveDNSServer", next) + } + if got := opt.Type(); got != 25 { + t.Errorf("got Type = %d, want = 31", got) + } + if got := opt.Length(); got != 22 { + t.Errorf("got Length = %d, want = 22", got) + } + if got, want := opt.Lifetime(), 16909320*time.Second; got != want { + t.Errorf("got Lifetime = %s, want = %s", got, want) + } + want := []tcpip.Address{ + "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + } + if got := opt.Addresses(); !cmp.Equal(got, want) { + t.Errorf("got Addresses = %v, want = %v", got, want) + } + + // Iterator should not return anything else. + next, done, err = it.Next() + if err != nil { + t.Errorf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if !done { + t.Error("got Next = (_, false, _), want = (_, true, _)") + } + if next != nil { + t.Errorf("got Next = (%x, _, _), want = (nil, _, _)", next) + } +} + +func TestNDPRecursiveDNSServerOption(t *testing.T) { + tests := []struct { + name string + buf []byte + lifetime time.Duration + addrs []tcpip.Address + }{ + { + "Valid1Addr", + []byte{ + 25, 3, 0, 0, + 0, 0, 0, 0, + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, + }, + 0, + []tcpip.Address{ + "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + }, + }, + { + "Valid2Addr", + []byte{ + 25, 5, 0, 0, + 0, 0, 0, 0, + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, + 17, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, + }, + 0, + []tcpip.Address{ + "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + "\x11\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x10", + }, + }, + { + "Valid3Addr", + []byte{ + 25, 7, 0, 0, + 0, 0, 0, 0, + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, + 17, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, + 17, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 17, + }, + 0, + []tcpip.Address{ + "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", + "\x11\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x10", + "\x11\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x11", + }, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + opts := NDPOptions(test.buf) + it, err := opts.Iter(true) + if err != nil { + t.Fatalf("got Iter = (_, %s), want = (_, nil)", err) + } + + // Iterator should get our option. + next, done, err := it.Next() + if err != nil { + t.Fatalf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if done { + t.Fatal("got Next = (_, true, _), want = (_, false, _)") + } + if got := next.Type(); got != NDPRecursiveDNSServerOptionType { + t.Fatalf("got Type %= %d, want = %d", got, NDPRecursiveDNSServerOptionType) + } + + opt, ok := next.(NDPRecursiveDNSServer) + if !ok { + t.Fatalf("next (type = %T) cannot be casted to an NDPRecursiveDNSServer", next) + } + if got := opt.Lifetime(); got != test.lifetime { + t.Errorf("got Lifetime = %d, want = %d", got, test.lifetime) + } + if got := opt.Addresses(); !cmp.Equal(got, test.addrs) { + t.Errorf("got Addresses = %v, want = %v", got, test.addrs) + } + + // Iterator should not return anything else. + next, done, err = it.Next() + if err != nil { + t.Errorf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if !done { + t.Error("got Next = (_, false, _), want = (_, true, _)") + } + if next != nil { + t.Errorf("got Next = (%x, _, _), want = (nil, _, _)", next) + } + }) + } +} + // TestNDPOptionsIterCheck tests that Iter will return false if the NDPOptions // the iterator was returned for is malformed. func TestNDPOptionsIterCheck(t *testing.T) { @@ -473,6 +643,51 @@ func TestNDPOptionsIterCheck(t *testing.T) { }, nil, }, + { + "InvalidRecursiveDNSServerCutsOffAddress", + []byte{ + 25, 4, 0, 0, + 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, + 0, 1, 2, 3, 4, 5, 6, 7, + }, + ErrNDPOptMalformedBody, + }, + { + "InvalidRecursiveDNSServerInvalidLengthField", + []byte{ + 25, 2, 0, 0, + 0, 0, 0, 0, + 0, 1, 2, 3, 4, 5, 6, 7, 8, + }, + ErrNDPInvalidLength, + }, + { + "RecursiveDNSServerTooSmall", + []byte{ + 25, 1, 0, 0, + 0, 0, 0, + }, + ErrNDPOptBufExhausted, + }, + { + "RecursiveDNSServerMulticast", + []byte{ + 25, 3, 0, 0, + 0, 0, 0, 0, + 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, + }, + ErrNDPOptMalformedBody, + }, + { + "RecursiveDNSServerUnspecified", + []byte{ + 25, 3, 0, 0, + 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + }, + ErrNDPOptMalformedBody, + }, } for _, test := range tests { diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index cfdd0496e..1d202deb5 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -596,7 +596,7 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { // Update the invalidation timer. timer := prefixState.invalidationTimer - if timer == nil && vl >= header.NDPPrefixInformationInfiniteLifetime { + if timer == nil && vl >= header.NDPInfiniteLifetime { // Had infinite valid lifetime before and // continues to have an invalid lifetime. Do // nothing further. @@ -615,7 +615,7 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { *prefixState.doNotInvalidate = true } - if vl >= header.NDPPrefixInformationInfiniteLifetime { + if vl >= header.NDPInfiniteLifetime { // Prefix is now valid forever so we don't need // an invalidation timer. prefixState.invalidationTimer = nil @@ -734,7 +734,7 @@ func (ndp *ndpState) rememberOnLinkPrefix(prefix tcpip.Subnet, l time.Duration) var timer *time.Timer // Only create a timer if the lifetime is not infinite. - if l < header.NDPPrefixInformationInfiniteLifetime { + if l < header.NDPInfiniteLifetime { timer = ndp.prefixInvalidationCallback(prefix, l, &doNotInvalidate) } diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go index 5b901f947..b2af78212 100644 --- a/pkg/tcpip/stack/ndp_test.go +++ b/pkg/tcpip/stack/ndp_test.go @@ -1364,10 +1364,10 @@ func TestPrefixDiscoveryWithInfiniteLifetime(t *testing.T) { // invalidate the prefix. const testInfiniteLifetimeSeconds = 2 const testInfiniteLifetime = testInfiniteLifetimeSeconds * time.Second - saved := header.NDPPrefixInformationInfiniteLifetime - header.NDPPrefixInformationInfiniteLifetime = testInfiniteLifetime + saved := header.NDPInfiniteLifetime + header.NDPInfiniteLifetime = testInfiniteLifetime defer func() { - header.NDPPrefixInformationInfiniteLifetime = saved + header.NDPInfiniteLifetime = saved }() prefix := tcpip.AddressWithPrefix{ -- cgit v1.2.3 From ab3f7bc39392aaa7e7961ae6d82d94f2cae18adb Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Fri, 6 Dec 2019 14:40:10 -0800 Subject: Do IPv6 Stateless Address Auto-Configuration (SLAAC) This change allows the netstack to do SLAAC as outlined by RFC 4862 section 5.5. Note, this change will not break existing uses of netstack as the default configuration for the stack options is set in such a way that SLAAC will not be performed. See `stack.Options` and `stack.NDPConfigurations` for more details. This change reuses 1 option and introduces a new one that is required to take advantage of SLAAC, all available under NDPConfigurations: - HandleRAs: Whether or not NDP RAs are processes - AutoGenGlobalAddresses: Whether or not SLAAC is performed. Also note, this change does not deprecate SLAAC generated addresses after the preferred lifetime. That will come in a later change (b/143713887). Currently, only the valid lifetime is honoured. Tests: Unittest to make sure that SLAAC generates and adds addresses only when configured to do so. Tests also makes sure that conflicts with static addresses do not modify the static address. PiperOrigin-RevId: 284265317 --- pkg/tcpip/header/ipv6.go | 49 +++- pkg/tcpip/header/ndp_options.go | 9 +- pkg/tcpip/stack/ndp.go | 509 ++++++++++++++++++++++++++++----- pkg/tcpip/stack/ndp_test.go | 616 +++++++++++++++++++++++++++++++++++++--- pkg/tcpip/stack/nic.go | 74 +++-- 5 files changed, 1109 insertions(+), 148 deletions(-) (limited to 'pkg/tcpip/header/ndp_options.go') diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go index 0caa51c1e..5275b34d4 100644 --- a/pkg/tcpip/header/ipv6.go +++ b/pkg/tcpip/header/ipv6.go @@ -90,6 +90,18 @@ const ( // IPv6Any is the non-routable IPv6 "any" meta address. It is also // known as the unspecified address. IPv6Any tcpip.Address = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" + + // IIDSize is the size of an interface identifier (IID), in bytes, as + // defined by RFC 4291 section 2.5.1. + IIDSize = 8 + + // IIDOffsetInIPv6Address is the offset, in bytes, from the start + // of an IPv6 address to the beginning of the interface identifier + // (IID) for auto-generated addresses. That is, all bytes before + // the IIDOffsetInIPv6Address-th byte are the prefix bytes, and all + // bytes including and after the IIDOffsetInIPv6Address-th byte are + // for the IID. + IIDOffsetInIPv6Address = 8 ) // IPv6EmptySubnet is the empty IPv6 subnet. It may also be known as the @@ -266,6 +278,28 @@ func SolicitedNodeAddr(addr tcpip.Address) tcpip.Address { return solicitedNodeMulticastPrefix + addr[len(addr)-3:] } +// EthernetAdddressToEUI64IntoBuf populates buf with a EUI-64 from a 48-bit +// Ethernet/MAC address. +// +// buf MUST be at least 8 bytes. +func EthernetAdddressToEUI64IntoBuf(linkAddr tcpip.LinkAddress, buf []byte) { + buf[0] = linkAddr[0] ^ 2 + buf[1] = linkAddr[1] + buf[2] = linkAddr[2] + buf[3] = 0xFE + buf[4] = 0xFE + buf[5] = linkAddr[3] + buf[6] = linkAddr[4] + buf[7] = linkAddr[5] +} + +// EthernetAddressToEUI64 computes an EUI-64 from a 48-bit Ethernet/MAC address. +func EthernetAddressToEUI64(linkAddr tcpip.LinkAddress) [IIDSize]byte { + var buf [IIDSize]byte + EthernetAdddressToEUI64IntoBuf(linkAddr, buf[:]) + return buf +} + // LinkLocalAddr computes the default IPv6 link-local address from a link-layer // (MAC) address. func LinkLocalAddr(linkAddr tcpip.LinkAddress) tcpip.Address { @@ -275,18 +309,11 @@ func LinkLocalAddr(linkAddr tcpip.LinkAddress) tcpip.Address { // The conversion is very nearly: // aa:bb:cc:dd:ee:ff => FE80::Aabb:ccFF:FEdd:eeff // Note the capital A. The conversion aa->Aa involves a bit flip. - lladdrb := [16]byte{ - 0: 0xFE, - 1: 0x80, - 8: linkAddr[0] ^ 2, - 9: linkAddr[1], - 10: linkAddr[2], - 11: 0xFF, - 12: 0xFE, - 13: linkAddr[3], - 14: linkAddr[4], - 15: linkAddr[5], + lladdrb := [IPv6AddressSize]byte{ + 0: 0xFE, + 1: 0x80, } + EthernetAdddressToEUI64IntoBuf(linkAddr, lladdrb[IIDOffsetInIPv6Address:]) return tcpip.Address(lladdrb[:]) } diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go index 2652e7b67..06e0bace2 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -17,6 +17,7 @@ package header import ( "encoding/binary" "errors" + "math" "time" "gvisor.dev/gvisor/pkg/tcpip" @@ -109,13 +110,13 @@ const ( ) var ( - // NDPInfiniteLifetime is a value that represents - // infinity for the Valid and Preferred Lifetime fields in a NDP Prefix - // Information option. Its value is (2^32 - 1)s = 4294967295s + // NDPInfiniteLifetime is a value that represents infinity for the + // 4-byte lifetime fields found in various NDP options. Its value is + // (2^32 - 1)s = 4294967295s. // // This is a variable instead of a constant so that tests can change // this value to a smaller value. It should only be modified by tests. - NDPInfiniteLifetime = time.Second * 4294967295 + NDPInfiniteLifetime = time.Second * math.MaxUint32 ) // NDPOptionIterator is an iterator of NDPOption. diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index 1d202deb5..75d3ecdac 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -58,6 +58,14 @@ const ( // Default = true. defaultDiscoverOnLinkPrefixes = true + // defaultAutoGenGlobalAddresses is the default configuration for + // whether or not to generate global IPv6 addresses in response to + // receiving a new Prefix Information option with its Autonomous + // Address AutoConfiguration flag set, as a host. + // + // Default = true. + defaultAutoGenGlobalAddresses = true + // minimumRetransmitTimer is the minimum amount of time to wait between // sending NDP Neighbor solicitation messages. Note, RFC 4861 does // not impose a minimum Retransmit Timer, but we do here to make sure @@ -87,6 +95,24 @@ const ( // // Max = 10. MaxDiscoveredOnLinkPrefixes = 10 + + // validPrefixLenForAutoGen is the expected prefix length that an + // address can be generated for. Must be 64 bits as the interface + // identifier (IID) is 64 bits and an IPv6 address is 128 bits, so + // 128 - 64 = 64. + validPrefixLenForAutoGen = 64 +) + +var ( + // MinPrefixInformationValidLifetimeForUpdate is the minimum Valid + // Lifetime to update the valid lifetime of a generated address by + // SLAAC. + // + // This is exported as a variable (instead of a constant) so tests + // can update it to a smaller value. + // + // Min = 2hrs. + MinPrefixInformationValidLifetimeForUpdate = 2 * time.Hour ) // NDPDispatcher is the interface integrators of netstack must implement to @@ -139,6 +165,22 @@ type NDPDispatcher interface { // This function is not permitted to block indefinitely. This function // is also not permitted to call into the stack. OnOnLinkPrefixInvalidated(nicID tcpip.NICID, prefix tcpip.Subnet) []tcpip.Route + + // OnAutoGenAddress will be called when a new prefix with its + // autonomous address-configuration flag set has been received and SLAAC + // has been performed. Implementations may prevent the stack from + // assigning the address to the NIC by returning false. + // + // This function is not permitted to block indefinitely. It must not + // call functions on the stack itself. + OnAutoGenAddress(tcpip.NICID, tcpip.AddressWithPrefix) bool + + // OnAutoGenAddressInvalidated will be called when an auto-generated + // address (as part of SLAAC) has been invalidated. + // + // This function is not permitted to block indefinitely. It must not + // call functions on the stack itself. + OnAutoGenAddressInvalidated(tcpip.NICID, tcpip.AddressWithPrefix) } // NDPConfigurations is the NDP configurations for the netstack. @@ -168,6 +210,17 @@ type NDPConfigurations struct { // will be discovered from Router Advertisements' Prefix Information // option. This configuration is ignored if HandleRAs is false. DiscoverOnLinkPrefixes bool + + // AutoGenGlobalAddresses determines whether or not global IPv6 + // addresses will be generated for a NIC in response to receiving a new + // Prefix Information option with its Autonomous Address + // AutoConfiguration flag set, as a host, as per RFC 4862 (SLAAC). + // + // Note, if an address was already generated for some unique prefix, as + // part of SLAAC, this option does not affect whether or not the + // lifetime(s) of the generated address changes; this option only + // affects the generation of new addresses as part of SLAAC. + AutoGenGlobalAddresses bool } // DefaultNDPConfigurations returns an NDPConfigurations populated with @@ -179,6 +232,7 @@ func DefaultNDPConfigurations() NDPConfigurations { HandleRAs: defaultHandleRAs, DiscoverDefaultRouters: defaultDiscoverDefaultRouters, DiscoverOnLinkPrefixes: defaultDiscoverOnLinkPrefixes, + AutoGenGlobalAddresses: defaultAutoGenGlobalAddresses, } } @@ -210,6 +264,9 @@ type ndpState struct { // The on-link prefixes discovered through Router Advertisements' Prefix // Information option. onLinkPrefixes map[tcpip.Subnet]onLinkPrefixState + + // The addresses generated by SLAAC. + autoGenAddresses map[tcpip.Address]autoGenAddressState } // dadState holds the Duplicate Address Detection timer and channel to signal @@ -270,6 +327,32 @@ type onLinkPrefixState struct { doNotInvalidate *bool } +// autoGenAddressState holds data associated with an address generated via +// SLAAC. +type autoGenAddressState struct { + invalidationTimer *time.Timer + + // Used to signal the timer not to invalidate the SLAAC address (A) in + // a race condition (T1 is a goroutine that handles a PI for A and T2 + // is the goroutine that handles A's invalidation timer firing): + // T1: Receive a new PI for A + // T1: Obtain the NIC's lock before processing the PI + // T2: A's invalidation timer fires, and gets blocked on obtaining the + // NIC's lock + // T1: Refreshes/extends A's lifetime & releases NIC's lock + // T2: Obtains NIC's lock & invalidates A immediately + // + // To resolve this, T1 will check to see if the timer already fired, and + // inform the timer using doNotInvalidate to not invalidate A, so that + // once T2 obtains the lock, it will see that it is set to true and do + // nothing further. + doNotInvalidate *bool + + // Nonzero only when the address is not valid forever (invalidationTimer + // is not nil). + validUntil time.Time +} + // startDuplicateAddressDetection performs Duplicate Address Detection. // // This function must only be called by IPv6 addresses that are currently @@ -536,17 +619,14 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { for opt, done, _ := it.Next(); !done; opt, done, _ = it.Next() { switch opt.Type() { case header.NDPPrefixInformationType: - if !ndp.configs.DiscoverOnLinkPrefixes { - continue - } - pi := opt.(header.NDPPrefixInformation) prefix := pi.Subnet() // Is the prefix a link-local? if header.IsV6LinkLocalAddress(prefix.ID()) { - // ...Yes, skip as per RFC 4861 section 6.3.4. + // ...Yes, skip as per RFC 4861 section 6.3.4, + // and RFC 4862 section 5.5.3.b (for SLAAC). continue } @@ -557,82 +637,13 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { continue } - if !pi.OnLinkFlag() { - // Not on-link so don't "discover" it as an - // on-link prefix. - continue - } - - prefixState, ok := ndp.onLinkPrefixes[prefix] - vl := pi.ValidLifetime() - switch { - case !ok && vl == 0: - // Don't know about this prefix but has a zero - // valid lifetime, so just ignore. - continue - - case !ok && vl != 0: - // This is a new on-link prefix we are - // discovering. - // - // Only remember it if we currently know about - // less than MaxDiscoveredOnLinkPrefixes on-link - // prefixes. - if len(ndp.onLinkPrefixes) < MaxDiscoveredOnLinkPrefixes { - ndp.rememberOnLinkPrefix(prefix, vl) - } - continue - - case ok && vl == 0: - // We know about the on-link prefix, but it is - // no longer to be considered on-link, so - // invalidate it. - ndp.invalidateOnLinkPrefix(prefix) - continue - } - - // This is an already discovered on-link prefix with a - // new non-zero valid lifetime. - // Update the invalidation timer. - timer := prefixState.invalidationTimer - - if timer == nil && vl >= header.NDPInfiniteLifetime { - // Had infinite valid lifetime before and - // continues to have an invalid lifetime. Do - // nothing further. - continue - } - - if timer != nil && !timer.Stop() { - // If we reach this point, then we know the - // timer already fired after we took the NIC - // lock. Inform the timer to not invalidate - // the prefix once it obtains the lock as we - // just got a new PI that refeshes its lifetime - // to a non-zero value. See - // onLinkPrefixState.doNotInvalidate for more - // details. - *prefixState.doNotInvalidate = true + if pi.OnLinkFlag() { + ndp.handleOnLinkPrefixInformation(pi) } - if vl >= header.NDPInfiniteLifetime { - // Prefix is now valid forever so we don't need - // an invalidation timer. - prefixState.invalidationTimer = nil - ndp.onLinkPrefixes[prefix] = prefixState - continue + if pi.AutonomousAddressConfigurationFlag() { + ndp.handleAutonomousPrefixInformation(pi) } - - if timer != nil { - // We already have a timer so just reset it to - // expire after the new valid lifetime. - timer.Reset(vl) - continue - } - - // We do not have a timer so just create a new one. - prefixState.invalidationTimer = ndp.prefixInvalidationCallback(prefix, vl, prefixState.doNotInvalidate) - ndp.onLinkPrefixes[prefix] = prefixState } // TODO(b/141556115): Do (MTU) Parameter Discovery. @@ -795,3 +806,345 @@ func (ndp *ndpState) prefixInvalidationCallback(prefix tcpip.Subnet, vl time.Dur ndp.invalidateOnLinkPrefix(prefix) }) } + +// handleOnLinkPrefixInformation handles a Prefix Information option with +// its on-link flag set, as per RFC 4861 section 6.3.4. +// +// handleOnLinkPrefixInformation assumes that the prefix this pi is for is +// not the link-local prefix and the on-link flag is set. +// +// The NIC that ndp belongs to and its associated stack MUST be locked. +func (ndp *ndpState) handleOnLinkPrefixInformation(pi header.NDPPrefixInformation) { + prefix := pi.Subnet() + prefixState, ok := ndp.onLinkPrefixes[prefix] + vl := pi.ValidLifetime() + + if !ok && vl == 0 { + // Don't know about this prefix but it has a zero valid + // lifetime, so just ignore. + return + } + + if !ok && vl != 0 { + // This is a new on-link prefix we are discovering + // + // Only remember it if we currently know about less than + // MaxDiscoveredOnLinkPrefixes on-link prefixes. + if ndp.configs.DiscoverOnLinkPrefixes && len(ndp.onLinkPrefixes) < MaxDiscoveredOnLinkPrefixes { + ndp.rememberOnLinkPrefix(prefix, vl) + } + return + } + + if ok && vl == 0 { + // We know about the on-link prefix, but it is + // no longer to be considered on-link, so + // invalidate it. + ndp.invalidateOnLinkPrefix(prefix) + return + } + + // This is an already discovered on-link prefix with a + // new non-zero valid lifetime. + // Update the invalidation timer. + timer := prefixState.invalidationTimer + + if timer == nil && vl >= header.NDPInfiniteLifetime { + // Had infinite valid lifetime before and + // continues to have an invalid lifetime. Do + // nothing further. + return + } + + if timer != nil && !timer.Stop() { + // If we reach this point, then we know the timer alread fired + // after we took the NIC lock. Inform the timer to not + // invalidate the prefix once it obtains the lock as we just + // got a new PI that refreshes its lifetime to a non-zero value. + // See onLinkPrefixState.doNotInvalidate for more details. + *prefixState.doNotInvalidate = true + } + + if vl >= header.NDPInfiniteLifetime { + // Prefix is now valid forever so we don't need + // an invalidation timer. + prefixState.invalidationTimer = nil + ndp.onLinkPrefixes[prefix] = prefixState + return + } + + if timer != nil { + // We already have a timer so just reset it to + // expire after the new valid lifetime. + timer.Reset(vl) + return + } + + // We do not have a timer so just create a new one. + prefixState.invalidationTimer = ndp.prefixInvalidationCallback(prefix, vl, prefixState.doNotInvalidate) + ndp.onLinkPrefixes[prefix] = prefixState +} + +// handleAutonomousPrefixInformation handles a Prefix Information option with +// its autonomous flag set, as per RFC 4862 section 5.5.3. +// +// handleAutonomousPrefixInformation assumes that the prefix this pi is for is +// not the link-local prefix and the autonomous flag is set. +// +// The NIC that ndp belongs to and its associated stack MUST be locked. +func (ndp *ndpState) handleAutonomousPrefixInformation(pi header.NDPPrefixInformation) { + vl := pi.ValidLifetime() + pl := pi.PreferredLifetime() + + // If the preferred lifetime is greater than the valid lifetime, + // silently ignore the Prefix Information option, as per RFC 4862 + // section 5.5.3.c. + if pl > vl { + return + } + + prefix := pi.Subnet() + + // Check if we already have an auto-generated address for prefix. + for _, ref := range ndp.nic.endpoints { + if ref.protocol != header.IPv6ProtocolNumber { + continue + } + + if ref.configType != slaac { + continue + } + + addr := ref.ep.ID().LocalAddress + refAddrWithPrefix := tcpip.AddressWithPrefix{Address: addr, PrefixLen: ref.ep.PrefixLen()} + if refAddrWithPrefix.Subnet() != prefix { + continue + } + + // + // At this point, we know we are refreshing a SLAAC generated + // IPv6 address with the prefix, prefix. Do the work as outlined + // by RFC 4862 section 5.5.3.e. + // + + addrState, ok := ndp.autoGenAddresses[addr] + if !ok { + panic(fmt.Sprintf("must have an autoGenAddressess entry for the SLAAC generated IPv6 address %s", addr)) + } + + // TODO(b/143713887): Handle deprecating auto-generated address + // after the preferred lifetime. + + // As per RFC 4862 section 5.5.3.e, the valid lifetime of the + // address generated by SLAAC is as follows: + // + // 1) If the received Valid Lifetime is greater than 2 hours or + // greater than RemainingLifetime, set the valid lifetime of + // the address to the advertised Valid Lifetime. + // + // 2) If RemainingLifetime is less than or equal to 2 hours, + // ignore the advertised Valid Lifetime. + // + // 3) Otherwise, reset the valid lifetime of the address to 2 + // hours. + + // Handle the infinite valid lifetime separately as we do not + // keep a timer in this case. + if vl >= header.NDPInfiniteLifetime { + if addrState.invalidationTimer != nil { + // Valid lifetime was finite before, but now it + // is valid forever. + if !addrState.invalidationTimer.Stop() { + *addrState.doNotInvalidate = true + } + addrState.invalidationTimer = nil + addrState.validUntil = time.Time{} + ndp.autoGenAddresses[addr] = addrState + } + + return + } + + var effectiveVl time.Duration + var rl time.Duration + + // If the address was originally set to be valid forever, + // assume the remaining time to be the maximum possible value. + if addrState.invalidationTimer == nil { + rl = header.NDPInfiniteLifetime + } else { + rl = time.Until(addrState.validUntil) + } + + if vl > MinPrefixInformationValidLifetimeForUpdate || vl > rl { + effectiveVl = vl + } else if rl <= MinPrefixInformationValidLifetimeForUpdate { + ndp.autoGenAddresses[addr] = addrState + return + } else { + effectiveVl = MinPrefixInformationValidLifetimeForUpdate + } + + if addrState.invalidationTimer == nil { + addrState.invalidationTimer = ndp.autoGenAddrInvalidationTimer(addr, effectiveVl, addrState.doNotInvalidate) + } else { + if !addrState.invalidationTimer.Stop() { + *addrState.doNotInvalidate = true + } + addrState.invalidationTimer.Reset(effectiveVl) + } + + addrState.validUntil = time.Now().Add(effectiveVl) + ndp.autoGenAddresses[addr] = addrState + return + } + + // We do not already have an address within the prefix, prefix. Do the + // work as outlined by RFC 4862 section 5.5.3.d if n is configured + // to auto-generated global addresses by SLAAC. + + // Are we configured to auto-generate new global addresses? + if !ndp.configs.AutoGenGlobalAddresses { + return + } + + // If we do not already have an address for this prefix and the valid + // lifetime is 0, no need to do anything further, as per RFC 4862 + // section 5.5.3.d. + if vl == 0 { + return + } + + // Make sure the prefix is valid (as far as its length is concerned) to + // generate a valid IPv6 address from an interface identifier (IID), as + // per RFC 4862 sectiion 5.5.3.d. + if prefix.Prefix() != validPrefixLenForAutoGen { + return + } + + // Only attempt to generate an interface-specific IID if we have a valid + // link address. + // + // TODO(b/141011931): Validate a LinkEndpoint's link address + // (provided by LinkEndpoint.LinkAddress) before reaching this + // point. + linkAddr := ndp.nic.linkEP.LinkAddress() + if !header.IsValidUnicastEthernetAddress(linkAddr) { + return + } + + // Generate an address within prefix from the EUI-64 of ndp's NIC's + // Ethernet MAC address. + addrBytes := make([]byte, header.IPv6AddressSize) + copy(addrBytes[:header.IIDOffsetInIPv6Address], prefix.ID()[:header.IIDOffsetInIPv6Address]) + header.EthernetAdddressToEUI64IntoBuf(linkAddr, addrBytes[header.IIDOffsetInIPv6Address:]) + addr := tcpip.Address(addrBytes) + addrWithPrefix := tcpip.AddressWithPrefix{ + Address: addr, + PrefixLen: validPrefixLenForAutoGen, + } + + // If the nic already has this address, do nothing further. + if ndp.nic.hasPermanentAddrLocked(addr) { + return + } + + // Inform the integrator that we have a new SLAAC address. + if ndp.nic.stack.ndpDisp == nil { + return + } + if !ndp.nic.stack.ndpDisp.OnAutoGenAddress(ndp.nic.ID(), addrWithPrefix) { + // Informed by the integrator not to add the address. + return + } + + if _, err := ndp.nic.addAddressLocked(tcpip.ProtocolAddress{ + Protocol: header.IPv6ProtocolNumber, + AddressWithPrefix: addrWithPrefix, + }, FirstPrimaryEndpoint, permanent, slaac); err != nil { + panic(err) + } + + // Setup the timers to deprecate and invalidate this newly generated + // address. + + // TODO(b/143713887): Handle deprecating auto-generated addresses + // after the preferred lifetime. + + var doNotInvalidate bool + var vTimer *time.Timer + if vl < header.NDPInfiniteLifetime { + vTimer = ndp.autoGenAddrInvalidationTimer(addr, vl, &doNotInvalidate) + } + + ndp.autoGenAddresses[addr] = autoGenAddressState{ + invalidationTimer: vTimer, + doNotInvalidate: &doNotInvalidate, + validUntil: time.Now().Add(vl), + } +} + +// invalidateAutoGenAddress invalidates an auto-generated address. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) invalidateAutoGenAddress(addr tcpip.Address) { + if !ndp.cleanupAutoGenAddrResourcesAndNotify(addr) { + return + } + + ndp.nic.removePermanentAddressLocked(addr) +} + +// cleanupAutoGenAddrResourcesAndNotify cleans up an invalidated auto-generated +// address's resources from ndp. If the stack has an NDP dispatcher, it will +// be notified that addr has been invalidated. +// +// Returns true if ndp had resources for addr to cleanup. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) cleanupAutoGenAddrResourcesAndNotify(addr tcpip.Address) bool { + state, ok := ndp.autoGenAddresses[addr] + + if !ok { + return false + } + + if state.invalidationTimer != nil { + state.invalidationTimer.Stop() + state.invalidationTimer = nil + *state.doNotInvalidate = true + } + + state.doNotInvalidate = nil + + delete(ndp.autoGenAddresses, addr) + + if ndp.nic.stack.ndpDisp != nil { + ndp.nic.stack.ndpDisp.OnAutoGenAddressInvalidated(ndp.nic.ID(), tcpip.AddressWithPrefix{ + Address: addr, + PrefixLen: validPrefixLenForAutoGen, + }) + } + + return true +} + +// autoGenAddrInvalidationTimer returns a new invalidation timer for an +// auto-generated address that fires after vl. +// +// doNotInvalidate is used to inform the timer when it fires at the same time +// that an auto-generated address's valid lifetime gets refreshed. See +// autoGenAddrState.doNotInvalidate for more details. +func (ndp *ndpState) autoGenAddrInvalidationTimer(addr tcpip.Address, vl time.Duration, doNotInvalidate *bool) *time.Timer { + return time.AfterFunc(vl, func() { + ndp.nic.mu.Lock() + defer ndp.nic.mu.Unlock() + + if *doNotInvalidate { + *doNotInvalidate = false + return + } + + ndp.invalidateAutoGenAddress(addr) + }) +} diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go index b2af78212..e9aa20148 100644 --- a/pkg/tcpip/stack/ndp_test.go +++ b/pkg/tcpip/stack/ndp_test.go @@ -38,7 +38,7 @@ const ( linkAddr1 = "\x02\x02\x03\x04\x05\x06" linkAddr2 = "\x02\x02\x03\x04\x05\x07" linkAddr3 = "\x02\x02\x03\x04\x05\x08" - defaultTimeout = 250 * time.Millisecond + defaultTimeout = 100 * time.Millisecond ) var ( @@ -47,6 +47,31 @@ var ( llAddr3 = header.LinkLocalAddr(linkAddr3) ) +// prefixSubnetAddr returns a prefix (Address + Length), the prefix's equivalent +// tcpip.Subnet, and an address where the lower half of the address is composed +// of the EUI-64 of linkAddr if it is a valid unicast ethernet address. +func prefixSubnetAddr(offset uint8, linkAddr tcpip.LinkAddress) (tcpip.AddressWithPrefix, tcpip.Subnet, tcpip.AddressWithPrefix) { + prefixBytes := []byte{1, 2, 3, 4, 5, 6, 7, 8 + offset, 0, 0, 0, 0, 0, 0, 0, 0} + prefix := tcpip.AddressWithPrefix{ + Address: tcpip.Address(prefixBytes), + PrefixLen: 64, + } + + subnet := prefix.Subnet() + + var addr tcpip.AddressWithPrefix + if header.IsValidUnicastEthernetAddress(linkAddr) { + addrBytes := []byte(subnet.ID()) + header.EthernetAdddressToEUI64IntoBuf(linkAddr, addrBytes[header.IIDOffsetInIPv6Address:]) + addr = tcpip.AddressWithPrefix{ + Address: tcpip.Address(addrBytes), + PrefixLen: 64, + } + } + + return prefix, subnet, addr +} + // TestDADDisabled tests that an address successfully resolves immediately // when DAD is not enabled (the default for an empty stack.Options). func TestDADDisabled(t *testing.T) { @@ -103,6 +128,19 @@ type ndpPrefixEvent struct { discovered bool } +type ndpAutoGenAddrEventType int + +const ( + newAddr ndpAutoGenAddrEventType = iota + invalidatedAddr +) + +type ndpAutoGenAddrEvent struct { + nicID tcpip.NICID + addr tcpip.AddressWithPrefix + eventType ndpAutoGenAddrEventType +} + var _ stack.NDPDispatcher = (*ndpDispatcher)(nil) // ndpDispatcher implements NDPDispatcher so tests can know when various NDP @@ -113,6 +151,7 @@ type ndpDispatcher struct { rememberRouter bool prefixC chan ndpPrefixEvent rememberPrefix bool + autoGenAddrC chan ndpAutoGenAddrEvent routeTable []tcpip.Route } @@ -211,7 +250,7 @@ func (n *ndpDispatcher) OnOnLinkPrefixInvalidated(nicID tcpip.NICID, prefix tcpi } } - rt := make([]tcpip.Route, 0) + var rt []tcpip.Route exclude := tcpip.Route{ Destination: prefix, NIC: nicID, @@ -226,6 +265,27 @@ func (n *ndpDispatcher) OnOnLinkPrefixInvalidated(nicID tcpip.NICID, prefix tcpi return rt } +func (n *ndpDispatcher) OnAutoGenAddress(nicID tcpip.NICID, addr tcpip.AddressWithPrefix) bool { + if n.autoGenAddrC != nil { + n.autoGenAddrC <- ndpAutoGenAddrEvent{ + nicID, + addr, + newAddr, + } + } + return true +} + +func (n *ndpDispatcher) OnAutoGenAddressInvalidated(nicID tcpip.NICID, addr tcpip.AddressWithPrefix) { + if n.autoGenAddrC != nil { + n.autoGenAddrC <- ndpAutoGenAddrEvent{ + nicID, + addr, + invalidatedAddr, + } + } +} + // TestDADResolve tests that an address successfully resolves after performing // DAD for various values of DupAddrDetectTransmits and RetransmitTimer. // Included in the subtests is a test to make sure that an invalid @@ -247,6 +307,8 @@ func TestDADResolve(t *testing.T) { for _, test := range tests { t.Run(test.name, func(t *testing.T) { + t.Parallel() + ndpDisp := ndpDispatcher{ dadC: make(chan ndpDADEvent), } @@ -781,16 +843,33 @@ func raBuf(ip tcpip.Address, rl uint16) tcpip.PacketBuffer { // // Note, raBufWithPI does not populate any of the RA fields other than the // Router Lifetime. -func raBufWithPI(ip tcpip.Address, rl uint16, prefix tcpip.AddressWithPrefix, onLink bool, vl uint32) tcpip.PacketBuffer { +func raBufWithPI(ip tcpip.Address, rl uint16, prefix tcpip.AddressWithPrefix, onLink, auto bool, vl, pl uint32) tcpip.PacketBuffer { flags := uint8(0) if onLink { - flags |= 128 + // The OnLink flag is the 7th bit in the flags byte. + flags |= 1 << 7 + } + if auto { + // The Address Auto-Configuration flag is the 6th bit in the + // flags byte. + flags |= 1 << 6 } + // A valid header.NDPPrefixInformation must be 30 bytes. buf := [30]byte{} + // The first byte in a header.NDPPrefixInformation is the Prefix Length + // field. buf[0] = uint8(prefix.PrefixLen) + // The 2nd byte within a header.NDPPrefixInformation is the Flags field. buf[1] = flags + // The Valid Lifetime field starts after the 2nd byte within a + // header.NDPPrefixInformation. binary.BigEndian.PutUint32(buf[2:], vl) + // The Preferred Lifetime field starts after the 6th byte within a + // header.NDPPrefixInformation. + binary.BigEndian.PutUint32(buf[6:], pl) + // The Prefix Address field starts after the 14th byte within a + // header.NDPPrefixInformation. copy(buf[14:], prefix.Address) return raBufWithOpts(ip, rl, header.NDPOptionsSerializer{ header.NDPPrefixInformation(buf[:]), @@ -800,6 +879,8 @@ func raBufWithPI(ip tcpip.Address, rl uint16, prefix tcpip.AddressWithPrefix, on // TestNoRouterDiscovery tests that router discovery will not be performed if // configured not to. func TestNoRouterDiscovery(t *testing.T) { + t.Parallel() + // Being configured to discover routers means handle and // discover are set to true and forwarding is set to false. // This tests all possible combinations of the configurations, @@ -812,6 +893,8 @@ func TestNoRouterDiscovery(t *testing.T) { forwarding := i&4 == 0 t.Run(fmt.Sprintf("HandleRAs(%t), DiscoverDefaultRouters(%t), Forwarding(%t)", handle, discover, forwarding), func(t *testing.T) { + t.Parallel() + ndpDisp := ndpDispatcher{ routerC: make(chan ndpRouterEvent, 10), } @@ -844,6 +927,8 @@ func TestNoRouterDiscovery(t *testing.T) { // TestRouterDiscoveryDispatcherNoRemember tests that the stack does not // remember a discovered router when the dispatcher asks it not to. func TestRouterDiscoveryDispatcherNoRemember(t *testing.T) { + t.Parallel() + ndpDisp := ndpDispatcher{ routerC: make(chan ndpRouterEvent, 10), } @@ -909,6 +994,8 @@ func TestRouterDiscoveryDispatcherNoRemember(t *testing.T) { } func TestRouterDiscovery(t *testing.T) { + t.Parallel() + ndpDisp := ndpDispatcher{ routerC: make(chan ndpRouterEvent, 10), rememberRouter: true, @@ -1040,6 +1127,8 @@ func TestRouterDiscovery(t *testing.T) { // TestRouterDiscoveryMaxRouters tests that only // stack.MaxDiscoveredDefaultRouters discovered routers are remembered. func TestRouterDiscoveryMaxRouters(t *testing.T) { + t.Parallel() + ndpDisp := ndpDispatcher{ routerC: make(chan ndpRouterEvent, 10), rememberRouter: true, @@ -1104,6 +1193,8 @@ func TestRouterDiscoveryMaxRouters(t *testing.T) { // TestNoPrefixDiscovery tests that prefix discovery will not be performed if // configured not to. func TestNoPrefixDiscovery(t *testing.T) { + t.Parallel() + prefix := tcpip.AddressWithPrefix{ Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x08\x00\x00\x00\x00\x00\x00\x00\x00"), PrefixLen: 64, @@ -1121,6 +1212,8 @@ func TestNoPrefixDiscovery(t *testing.T) { forwarding := i&4 == 0 t.Run(fmt.Sprintf("HandleRAs(%t), DiscoverOnLinkPrefixes(%t), Forwarding(%t)", handle, discover, forwarding), func(t *testing.T) { + t.Parallel() + ndpDisp := ndpDispatcher{ prefixC: make(chan ndpPrefixEvent, 10), } @@ -1140,7 +1233,7 @@ func TestNoPrefixDiscovery(t *testing.T) { } // Rx an RA with prefix with non-zero lifetime. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, 10)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, false, 10, 0)) select { case <-ndpDisp.prefixC: @@ -1154,11 +1247,9 @@ func TestNoPrefixDiscovery(t *testing.T) { // TestPrefixDiscoveryDispatcherNoRemember tests that the stack does not // remember a discovered on-link prefix when the dispatcher asks it not to. func TestPrefixDiscoveryDispatcherNoRemember(t *testing.T) { - prefix := tcpip.AddressWithPrefix{ - Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x08\x00\x00\x00\x00\x00\x00\x00\x00"), - PrefixLen: 64, - } - subnet := prefix.Subnet() + t.Parallel() + + prefix, subnet, _ := prefixSubnetAddr(0, "") ndpDisp := ndpDispatcher{ prefixC: make(chan ndpPrefixEvent, 10), @@ -1189,7 +1280,7 @@ func TestPrefixDiscoveryDispatcherNoRemember(t *testing.T) { // Rx an RA with prefix with a short lifetime. const lifetime = 1 - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, lifetime)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, false, lifetime, 0)) select { case r := <-ndpDisp.prefixC: if r.nicID != 1 { @@ -1226,21 +1317,11 @@ func TestPrefixDiscoveryDispatcherNoRemember(t *testing.T) { } func TestPrefixDiscovery(t *testing.T) { - prefix1 := tcpip.AddressWithPrefix{ - Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x08\x00\x00\x00\x00\x00\x00\x00\x00"), - PrefixLen: 64, - } - prefix2 := tcpip.AddressWithPrefix{ - Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x09\x00\x00\x00\x00\x00\x00\x00\x00"), - PrefixLen: 64, - } - prefix3 := tcpip.AddressWithPrefix{ - Address: tcpip.Address("\x01\x02\x03\x04\x05\x06\x07\x09\x0a\x00\x00\x00\x00\x00\x00\x00"), - PrefixLen: 72, - } - subnet1 := prefix1.Subnet() - subnet2 := prefix2.Subnet() - subnet3 := prefix3.Subnet() + t.Parallel() + + prefix1, subnet1, _ := prefixSubnetAddr(0, "") + prefix2, subnet2, _ := prefixSubnetAddr(1, "") + prefix3, subnet3, _ := prefixSubnetAddr(2, "") ndpDisp := ndpDispatcher{ prefixC: make(chan ndpPrefixEvent, 10), @@ -1281,7 +1362,7 @@ func TestPrefixDiscovery(t *testing.T) { // Receive an RA with prefix1 in an NDP Prefix Information option (PI) // with zero valid lifetime. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, 0)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, false, 0, 0)) select { case <-ndpDisp.prefixC: t.Fatal("unexpectedly discovered a prefix with 0 lifetime") @@ -1290,7 +1371,7 @@ func TestPrefixDiscovery(t *testing.T) { // Receive an RA with prefix1 in an NDP Prefix Information option (PI) // with non-zero lifetime. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, 100)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, false, 100, 0)) waitForEvent(subnet1, true, defaultTimeout) // Should have added a device route for subnet1 through the nic. @@ -1299,7 +1380,7 @@ func TestPrefixDiscovery(t *testing.T) { } // Receive an RA with prefix2 in a PI. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix2, true, 100)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix2, true, false, 100, 0)) waitForEvent(subnet2, true, defaultTimeout) // Should have added a device route for subnet2 through the nic. @@ -1308,7 +1389,7 @@ func TestPrefixDiscovery(t *testing.T) { } // Receive an RA with prefix3 in a PI. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix3, true, 100)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix3, true, false, 100, 0)) waitForEvent(subnet3, true, defaultTimeout) // Should have added a device route for subnet3 through the nic. @@ -1317,7 +1398,7 @@ func TestPrefixDiscovery(t *testing.T) { } // Receive an RA with prefix1 in a PI with lifetime = 0. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, 0)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, false, 0, 0)) waitForEvent(subnet1, false, defaultTimeout) // Should have removed the device route for subnet1 through the nic. @@ -1327,7 +1408,7 @@ func TestPrefixDiscovery(t *testing.T) { // Receive an RA with prefix2 in a PI with lesser lifetime. lifetime := uint32(2) - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix2, true, lifetime)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix2, true, false, lifetime, 0)) select { case <-ndpDisp.prefixC: t.Fatal("unexpectedly received prefix event when updating lifetime") @@ -1349,7 +1430,7 @@ func TestPrefixDiscovery(t *testing.T) { } // Receive RA to invalidate prefix3. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix3, true, 0)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix3, true, false, 0, 0)) waitForEvent(subnet3, false, defaultTimeout) // Should not have any routes. @@ -1415,7 +1496,7 @@ func TestPrefixDiscoveryWithInfiniteLifetime(t *testing.T) { // Receive an RA with prefix in an NDP Prefix Information option (PI) // with infinite valid lifetime which should not get invalidated. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, testInfiniteLifetimeSeconds)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, false, testInfiniteLifetimeSeconds, 0)) waitForEvent(true, defaultTimeout) select { case <-ndpDisp.prefixC: @@ -1425,16 +1506,16 @@ func TestPrefixDiscoveryWithInfiniteLifetime(t *testing.T) { // Receive an RA with finite lifetime. // The prefix should get invalidated after 1s. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, testInfiniteLifetimeSeconds-1)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, false, testInfiniteLifetimeSeconds-1, 0)) waitForEvent(false, testInfiniteLifetime) // Receive an RA with finite lifetime. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, testInfiniteLifetimeSeconds-1)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, false, testInfiniteLifetimeSeconds-1, 0)) waitForEvent(true, defaultTimeout) // Receive an RA with prefix with an infinite lifetime. // The prefix should not be invalidated. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, testInfiniteLifetimeSeconds)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, false, testInfiniteLifetimeSeconds, 0)) select { case <-ndpDisp.prefixC: t.Fatal("unexpectedly invalidated a prefix with infinite lifetime") @@ -1443,7 +1524,7 @@ func TestPrefixDiscoveryWithInfiniteLifetime(t *testing.T) { // Receive an RA with a prefix with a lifetime value greater than the // set infinite lifetime value. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, testInfiniteLifetimeSeconds+1)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, false, testInfiniteLifetimeSeconds+1, 0)) select { case <-ndpDisp.prefixC: t.Fatal("unexpectedly invalidated a prefix with infinite lifetime") @@ -1452,13 +1533,15 @@ func TestPrefixDiscoveryWithInfiniteLifetime(t *testing.T) { // Receive an RA with 0 lifetime. // The prefix should get invalidated. - e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, 0)) + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, false, 0, 0)) waitForEvent(false, defaultTimeout) } // TestPrefixDiscoveryMaxRouters tests that only // stack.MaxDiscoveredOnLinkPrefixes discovered on-link prefixes are remembered. func TestPrefixDiscoveryMaxOnLinkPrefixes(t *testing.T) { + t.Parallel() + ndpDisp := ndpDispatcher{ prefixC: make(chan ndpPrefixEvent, stack.MaxDiscoveredOnLinkPrefixes+3), rememberPrefix: true, @@ -1537,3 +1620,458 @@ func TestPrefixDiscoveryMaxOnLinkPrefixes(t *testing.T) { t.Fatalf("got GetRouteTable = %v, want = %v", got, expectedRt) } } + +// Checks to see if list contains an IPv6 address, item. +func contains(list []tcpip.ProtocolAddress, item tcpip.AddressWithPrefix) bool { + protocolAddress := tcpip.ProtocolAddress{ + Protocol: header.IPv6ProtocolNumber, + AddressWithPrefix: item, + } + + for _, i := range list { + if i == protocolAddress { + return true + } + } + + return false +} + +// TestNoAutoGenAddr tests that SLAAC is not performed when configured not to. +func TestNoAutoGenAddr(t *testing.T) { + t.Parallel() + + prefix, _, _ := prefixSubnetAddr(0, "") + + // Being configured to auto-generate addresses means handle and + // autogen are set to true and forwarding is set to false. + // This tests all possible combinations of the configurations, + // except for the configuration where handle = true, autogen = + // true and forwarding = false (the required configuration to do + // SLAAC) - that will done in other tests. + for i := 0; i < 7; i++ { + handle := i&1 != 0 + autogen := i&2 != 0 + forwarding := i&4 == 0 + + t.Run(fmt.Sprintf("HandleRAs(%t), AutoGenAddr(%t), Forwarding(%t)", handle, autogen, forwarding), func(t *testing.T) { + t.Parallel() + + ndpDisp := ndpDispatcher{ + autoGenAddrC: make(chan ndpAutoGenAddrEvent, 10), + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: handle, + AutoGenGlobalAddresses: autogen, + }, + NDPDisp: &ndpDisp, + }) + s.SetForwarding(forwarding) + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Rx an RA with prefix with non-zero lifetime. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, false, true, 10, 0)) + + select { + case <-ndpDisp.autoGenAddrC: + t.Fatal("unexpectedly auto-generated an address when configured not to") + case <-time.After(defaultTimeout): + } + }) + } +} + +// TestAutoGenAddr tests that an address is properly generated and invalidated +// when configured to do so. +func TestAutoGenAddr(t *testing.T) { + const newMinVL = 2 + newMinVLDuration := newMinVL * time.Second + saved := stack.MinPrefixInformationValidLifetimeForUpdate + defer func() { + stack.MinPrefixInformationValidLifetimeForUpdate = saved + }() + stack.MinPrefixInformationValidLifetimeForUpdate = newMinVLDuration + + prefix1, _, addr1 := prefixSubnetAddr(0, linkAddr1) + prefix2, _, addr2 := prefixSubnetAddr(1, linkAddr1) + + ndpDisp := ndpDispatcher{ + autoGenAddrC: make(chan ndpAutoGenAddrEvent, 10), + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + AutoGenGlobalAddresses: true, + }, + NDPDisp: &ndpDisp, + }) + + waitForEvent := func(addr tcpip.AddressWithPrefix, eventType ndpAutoGenAddrEventType, timeout time.Duration) { + t.Helper() + + select { + case r := <-ndpDisp.autoGenAddrC: + if r.nicID != 1 { + t.Fatalf("got r.nicID = %d, want = 1", r.nicID) + } + if r.addr != addr { + t.Fatalf("got r.addr = %s, want = %s", r.addr, addr) + } + if r.eventType != eventType { + t.Fatalf("got r.eventType = %v, want = %v", r.eventType, eventType) + } + case <-time.After(timeout): + t.Fatal("timeout waiting for addr auto gen event") + } + } + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Receive an RA with prefix1 in an NDP Prefix Information option (PI) + // with zero valid lifetime. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, true, 0, 0)) + select { + case <-ndpDisp.autoGenAddrC: + t.Fatal("unexpectedly auto-generated an address with 0 lifetime") + case <-time.After(defaultTimeout): + } + + // Receive an RA with prefix1 in an NDP Prefix Information option (PI) + // with non-zero lifetime. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, true, 100, 0)) + waitForEvent(addr1, newAddr, defaultTimeout) + if !contains(s.NICInfo()[1].ProtocolAddresses, addr1) { + t.Fatalf("Should have %s in the list of addresses", addr1) + } + + // Receive an RA with prefix2 in an NDP Prefix Information option (PI) + // with preferred lifetime > valid lifetime + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, true, 5, 6)) + select { + case <-ndpDisp.autoGenAddrC: + t.Fatal("unexpectedly auto-generated an address with preferred lifetime > valid lifetime") + case <-time.After(defaultTimeout): + } + + // Receive an RA with prefix2 in a PI. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix2, true, true, 100, 0)) + waitForEvent(addr2, newAddr, defaultTimeout) + if !contains(s.NICInfo()[1].ProtocolAddresses, addr1) { + t.Fatalf("Should have %s in the list of addresses", addr1) + } + if !contains(s.NICInfo()[1].ProtocolAddresses, addr2) { + t.Fatalf("Should have %s in the list of addresses", addr2) + } + + // Refresh valid lifetime for addr of prefix1. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix1, true, true, newMinVL, 0)) + select { + case <-ndpDisp.autoGenAddrC: + t.Fatal("unexpectedly auto-generated an address when we already have an address for a prefix") + case <-time.After(defaultTimeout): + } + + // Wait for addr of prefix1 to be invalidated. + waitForEvent(addr1, invalidatedAddr, newMinVLDuration+defaultTimeout) + if contains(s.NICInfo()[1].ProtocolAddresses, addr1) { + t.Fatalf("Should not have %s in the list of addresses", addr1) + } + if !contains(s.NICInfo()[1].ProtocolAddresses, addr2) { + t.Fatalf("Should have %s in the list of addresses", addr2) + } +} + +// TestAutoGenAddrValidLifetimeUpdates tests that the valid lifetime of an +// auto-generated address only gets updated when required to, as specified in +// RFC 4862 section 5.5.3.e. +func TestAutoGenAddrValidLifetimeUpdates(t *testing.T) { + const infiniteVL = 4294967295 + const newMinVL = 5 + saved := stack.MinPrefixInformationValidLifetimeForUpdate + defer func() { + stack.MinPrefixInformationValidLifetimeForUpdate = saved + }() + stack.MinPrefixInformationValidLifetimeForUpdate = newMinVL * time.Second + + prefix, _, addr := prefixSubnetAddr(0, linkAddr1) + + tests := []struct { + name string + ovl uint32 + nvl uint32 + evl uint32 + }{ + // Should update the VL to the minimum VL for updating if the + // new VL is less than newMinVL but was originally greater than + // it. + { + "LargeVLToVLLessThanMinVLForUpdate", + 9999, + 1, + newMinVL, + }, + { + "LargeVLTo0", + 9999, + 0, + newMinVL, + }, + { + "InfiniteVLToVLLessThanMinVLForUpdate", + infiniteVL, + 1, + newMinVL, + }, + { + "InfiniteVLTo0", + infiniteVL, + 0, + newMinVL, + }, + + // Should not update VL if original VL was less than newMinVL + // and the new VL is also less than newMinVL. + { + "ShouldNotUpdateWhenBothOldAndNewAreLessThanMinVLForUpdate", + newMinVL - 1, + newMinVL - 3, + newMinVL - 1, + }, + + // Should take the new VL if the new VL is greater than the + // remaining time or is greater than newMinVL. + { + "MorethanMinVLToLesserButStillMoreThanMinVLForUpdate", + newMinVL + 5, + newMinVL + 3, + newMinVL + 3, + }, + { + "SmallVLToGreaterVLButStillLessThanMinVLForUpdate", + newMinVL - 3, + newMinVL - 1, + newMinVL - 1, + }, + { + "SmallVLToGreaterVLThatIsMoreThaMinVLForUpdate", + newMinVL - 3, + newMinVL + 1, + newMinVL + 1, + }, + } + + const delta = 500 * time.Millisecond + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + t.Parallel() + + ndpDisp := ndpDispatcher{ + autoGenAddrC: make(chan ndpAutoGenAddrEvent, 10), + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + AutoGenGlobalAddresses: true, + }, + NDPDisp: &ndpDisp, + }) + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Receive an RA with prefix with initial VL, test.ovl. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, true, test.ovl, 0)) + select { + case r := <-ndpDisp.autoGenAddrC: + if r.nicID != 1 { + t.Fatalf("got r.nicID = %d, want = 1", r.nicID) + } + if r.addr != addr { + t.Fatalf("got r.addr = %s, want = %s", r.addr, addr) + } + if r.eventType != newAddr { + t.Fatalf("got r.eventType = %v, want = %v", r.eventType, newAddr) + } + case <-time.After(defaultTimeout): + t.Fatal("timeout waiting for addr auto gen event") + } + + // Receive an new RA with prefix with new VL, test.nvl. + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, true, test.nvl, 0)) + + // + // Validate that the VL for the address got set to + // test.evl. + // + + // Make sure we do not get any invalidation events + // until atleast 500ms (delta) before test.evl. + select { + case <-ndpDisp.autoGenAddrC: + t.Fatalf("unexpectedly received an auto gen addr event") + case <-time.After(time.Duration(test.evl)*time.Second - delta): + } + + // Wait for another second (2x delta), but now we expect + // the invalidation event. + select { + case r := <-ndpDisp.autoGenAddrC: + if r.nicID != 1 { + t.Fatalf("got r.nicID = %d, want = 1", r.nicID) + } + if r.addr != addr { + t.Fatalf("got r.addr = %s, want = %s", r.addr, addr) + } + if r.eventType != invalidatedAddr { + t.Fatalf("got r.eventType = %v, want = %v", r.eventType, newAddr) + } + case <-time.After(2 * delta): + t.Fatal("timeout waiting for addr auto gen event") + } + }) + } +} + +// TestAutoGenAddrRemoval tests that when auto-generated addresses are removed +// by the user, its resources will be cleaned up and an invalidation event will +// be sent to the integrator. +func TestAutoGenAddrRemoval(t *testing.T) { + t.Parallel() + + prefix, _, addr := prefixSubnetAddr(0, linkAddr1) + + ndpDisp := ndpDispatcher{ + autoGenAddrC: make(chan ndpAutoGenAddrEvent, 10), + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + AutoGenGlobalAddresses: true, + }, + NDPDisp: &ndpDisp, + }) + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Receive an RA with prefix with its valid lifetime = lifetime. + const lifetime = 5 + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, true, lifetime, 0)) + select { + case r := <-ndpDisp.autoGenAddrC: + if r.nicID != 1 { + t.Fatalf("got r.nicID = %d, want = 1", r.nicID) + } + if r.addr != addr { + t.Fatalf("got r.addr = %s, want = %s", r.addr, addr) + } + if r.eventType != newAddr { + t.Fatalf("got r.eventType = %v, want = %v", r.eventType, newAddr) + } + case <-time.After(defaultTimeout): + t.Fatal("timeout waiting for addr auto gen event") + } + + // Remove the address. + if err := s.RemoveAddress(1, addr.Address); err != nil { + t.Fatalf("RemoveAddress(_, %s) = %s", addr.Address, err) + } + + // Should get the invalidation event immediately. + select { + case r := <-ndpDisp.autoGenAddrC: + if r.nicID != 1 { + t.Fatalf("got r.nicID = %d, want = 1", r.nicID) + } + if r.addr != addr { + t.Fatalf("got r.addr = %s, want = %s", r.addr, addr) + } + if r.eventType != invalidatedAddr { + t.Fatalf("got r.eventType = %v, want = %v", r.eventType, newAddr) + } + case <-time.After(defaultTimeout): + t.Fatal("timeout waiting for addr auto gen event") + } + + // Wait for the original valid lifetime to make sure the original timer + // got stopped/cleaned up. + select { + case <-ndpDisp.autoGenAddrC: + t.Fatalf("unexpectedly received an auto gen addr event") + case <-time.After(lifetime*time.Second + defaultTimeout): + } +} + +// TestAutoGenAddrStaticConflict tests that if SLAAC generates an address that +// is already assigned to the NIC, the static address remains. +func TestAutoGenAddrStaticConflict(t *testing.T) { + t.Parallel() + + prefix, _, addr := prefixSubnetAddr(0, linkAddr1) + + ndpDisp := ndpDispatcher{ + autoGenAddrC: make(chan ndpAutoGenAddrEvent, 10), + } + e := channel.New(10, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + AutoGenGlobalAddresses: true, + }, + NDPDisp: &ndpDisp, + }) + + if err := s.CreateNIC(1, e); err != nil { + t.Fatalf("CreateNIC(1) = %s", err) + } + + // Add the address as a static address before SLAAC tries to add it. + if err := s.AddProtocolAddress(1, tcpip.ProtocolAddress{Protocol: header.IPv6ProtocolNumber, AddressWithPrefix: addr}); err != nil { + t.Fatalf("AddAddress(_, %d, %s) = %s", header.IPv6ProtocolNumber, addr.Address, err) + } + if !contains(s.NICInfo()[1].ProtocolAddresses, addr) { + t.Fatalf("Should have %s in the list of addresses", addr1) + } + + // Receive a PI where the generated address will be the same as the one + // that we already have assigned statically. + const lifetime = 5 + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithPI(llAddr2, 0, prefix, true, true, lifetime, 0)) + select { + case <-ndpDisp.autoGenAddrC: + t.Fatal("unexpectedly received an auto gen addr event for an address we already have statically") + case <-time.After(defaultTimeout): + } + if !contains(s.NICInfo()[1].ProtocolAddresses, addr) { + t.Fatalf("Should have %s in the list of addresses", addr1) + } + + // Should not get an invalidation event after the PI's invalidation + // time. + select { + case <-ndpDisp.autoGenAddrC: + t.Fatal("unexpectedly received an auto gen addr event") + case <-time.After(lifetime*time.Second + defaultTimeout): + } + if !contains(s.NICInfo()[1].ProtocolAddresses, addr) { + t.Fatalf("Should have %s in the list of addresses", addr1) + } +} diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index 3f8d7312c..e8401c673 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -115,10 +115,11 @@ func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, loopback }, }, ndp: ndpState{ - configs: stack.ndpConfigs, - dad: make(map[tcpip.Address]dadState), - defaultRouters: make(map[tcpip.Address]defaultRouterState), - onLinkPrefixes: make(map[tcpip.Subnet]onLinkPrefixState), + configs: stack.ndpConfigs, + dad: make(map[tcpip.Address]dadState), + defaultRouters: make(map[tcpip.Address]defaultRouterState), + onLinkPrefixes: make(map[tcpip.Subnet]onLinkPrefixState), + autoGenAddresses: make(map[tcpip.Address]autoGenAddressState), }, } nic.ndp.nic = nic @@ -244,6 +245,20 @@ func (n *NIC) primaryEndpoint(protocol tcpip.NetworkProtocolNumber) *referencedN return nil } +// hasPermanentAddrLocked returns true if n has a permanent (including currently +// tentative) address, addr. +func (n *NIC) hasPermanentAddrLocked(addr tcpip.Address) bool { + ref, ok := n.endpoints[NetworkEndpointID{addr}] + + if !ok { + return false + } + + kind := ref.getKind() + + return kind == permanent || kind == permanentTentative +} + func (n *NIC) getRef(protocol tcpip.NetworkProtocolNumber, dst tcpip.Address) *referencedNetworkEndpoint { return n.getRefOrCreateTemp(protocol, dst, CanBePrimaryEndpoint, n.promiscuous) } @@ -335,7 +350,7 @@ func (n *NIC) getRefOrCreateTemp(protocol tcpip.NetworkProtocolNumber, address t Address: address, PrefixLen: netProto.DefaultPrefixLen(), }, - }, peb, temporary) + }, peb, temporary, static) n.mu.Unlock() return ref @@ -384,10 +399,10 @@ func (n *NIC) addPermanentAddressLocked(protocolAddress tcpip.ProtocolAddress, p } } - return n.addAddressLocked(protocolAddress, peb, permanent) + return n.addAddressLocked(protocolAddress, peb, permanent, static) } -func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior, kind networkEndpointKind) (*referencedNetworkEndpoint, *tcpip.Error) { +func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior, kind networkEndpointKind, configType networkEndpointConfigType) (*referencedNetworkEndpoint, *tcpip.Error) { // TODO(b/141022673): Validate IP address before adding them. // Sanity check. @@ -417,11 +432,12 @@ func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb Primar } ref := &referencedNetworkEndpoint{ - refs: 1, - ep: ep, - nic: n, - protocol: protocolAddress.Protocol, - kind: kind, + refs: 1, + ep: ep, + nic: n, + protocol: protocolAddress.Protocol, + kind: kind, + configType: configType, } // Set up cache if link address resolution exists for this protocol. @@ -624,9 +640,18 @@ func (n *NIC) removePermanentAddressLocked(addr tcpip.Address) *tcpip.Error { isIPv6Unicast := r.protocol == header.IPv6ProtocolNumber && header.IsV6UnicastAddress(addr) - // If we are removing a tentative IPv6 unicast address, stop DAD. - if isIPv6Unicast && kind == permanentTentative { - n.ndp.stopDuplicateAddressDetection(addr) + if isIPv6Unicast { + // If we are removing a tentative IPv6 unicast address, stop + // DAD. + if kind == permanentTentative { + n.ndp.stopDuplicateAddressDetection(addr) + } + + // If we are removing an address generated via SLAAC, cleanup + // its SLAAC resources and notify the integrator. + if r.configType == slaac { + n.ndp.cleanupAutoGenAddrResourcesAndNotify(addr) + } } r.setKind(permanentExpired) @@ -989,7 +1014,7 @@ const ( // removing the permanent address from the NIC. permanent - // An expired permanent endoint is a permanent endoint that had its address + // An expired permanent endpoint is a permanent endpoint that had its address // removed from the NIC, and it is waiting to be removed once no more routes // hold a reference to it. This is achieved by decreasing its reference count // by 1. If its address is re-added before the endpoint is removed, its type @@ -1035,6 +1060,19 @@ func (n *NIC) unregisterPacketEndpoint(netProto tcpip.NetworkProtocolNumber, ep } } +type networkEndpointConfigType int32 + +const ( + // A statically configured endpoint is an address that was added by + // some user-specified action (adding an explicit address, joining a + // multicast group). + static networkEndpointConfigType = iota + + // A slaac configured endpoint is an IPv6 endpoint that was + // added by SLAAC as per RFC 4862 section 5.5.3. + slaac +) + type referencedNetworkEndpoint struct { ep NetworkEndpoint nic *NIC @@ -1050,6 +1088,10 @@ type referencedNetworkEndpoint struct { // networkEndpointKind must only be accessed using {get,set}Kind(). kind networkEndpointKind + + // configType is the method that was used to configure this endpoint. + // This must never change after the endpoint is added to a NIC. + configType networkEndpointConfigType } func (r *referencedNetworkEndpoint) getKind() networkEndpointKind { -- cgit v1.2.3 From 2a2da5be31ea3c32e66f0c0ff61ef189848f5258 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Mon, 27 Jan 2020 20:28:14 -0800 Subject: Add a type to represent the NDP Source Link Layer Address option Tests: - header.TestNDPSourceLinkLayerAddressOptionEthernetAddress - header.TestNDPSourceLinkLayerAddressOptionSerialize - header.TestNDPOptionsIterCheck - header.TestNDPOptionsIter PiperOrigin-RevId: 291856429 --- pkg/tcpip/header/icmpv6.go | 2 +- pkg/tcpip/header/ndp_options.go | 52 ++++++++++-- pkg/tcpip/header/ndp_test.go | 180 ++++++++++++++++++++++++++++++++++++---- 3 files changed, 214 insertions(+), 20 deletions(-) (limited to 'pkg/tcpip/header/ndp_options.go') diff --git a/pkg/tcpip/header/icmpv6.go b/pkg/tcpip/header/icmpv6.go index b4037b6c8..b095dc0ab 100644 --- a/pkg/tcpip/header/icmpv6.go +++ b/pkg/tcpip/header/icmpv6.go @@ -52,7 +52,7 @@ const ( // ICMPv6NeighborAdvertSize is size of a neighbor advertisement // including the NDP Target Link Layer option for an Ethernet // address. - ICMPv6NeighborAdvertSize = ICMPv6HeaderSize + NDPNAMinimumSize + ndpTargetEthernetLinkLayerAddressSize + ICMPv6NeighborAdvertSize = ICMPv6HeaderSize + NDPNAMinimumSize + ndpLinkLayerAddressSize // ICMPv6EchoMinimumSize is the minimum size of a valid ICMP echo packet. ICMPv6EchoMinimumSize = 8 diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go index 06e0bace2..1e60f3d4f 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -24,13 +24,17 @@ import ( ) const ( - // NDPTargetLinkLayerAddressOptionType is the type of the Target - // Link-Layer Address option, as per RFC 4861 section 4.6.1. + // NDPSourceLinkLayerAddressOptionType is the type of the Source Link Layer + // Address option, as per RFC 4861 section 4.6.1. + NDPSourceLinkLayerAddressOptionType = 1 + + // NDPTargetLinkLayerAddressOptionType is the type of the Target Link Layer + // Address option, as per RFC 4861 section 4.6.1. NDPTargetLinkLayerAddressOptionType = 2 - // ndpTargetEthernetLinkLayerAddressSize is the size of a Target - // Link Layer Option for an Ethernet address. - ndpTargetEthernetLinkLayerAddressSize = 8 + // ndpLinkLayerAddressSize is the size of a Source or Target Link Layer + // Address option. + ndpLinkLayerAddressSize = 8 // NDPPrefixInformationType is the type of the Prefix Information // option, as per RFC 4861 section 4.6.2. @@ -189,6 +193,9 @@ func (i *NDPOptionIterator) Next() (NDPOption, bool, error) { i.opts = i.opts[numBytes:] switch t { + case NDPSourceLinkLayerAddressOptionType: + return NDPSourceLinkLayerAddressOption(body), false, nil + case NDPTargetLinkLayerAddressOptionType: return NDPTargetLinkLayerAddressOption(body), false, nil @@ -368,6 +375,41 @@ func (b NDPOptionsSerializer) Length() int { return l } +// NDPSourceLinkLayerAddressOption is the NDP Source Link Layer Option +// as defined by RFC 4861 section 4.6.1. +// +// It is the first X bytes following the NDP option's Type and Length field +// where X is the value in Length multiplied by lengthByteUnits - 2 bytes. +type NDPSourceLinkLayerAddressOption tcpip.LinkAddress + +// Type implements NDPOption.Type. +func (o NDPSourceLinkLayerAddressOption) Type() uint8 { + return NDPSourceLinkLayerAddressOptionType +} + +// Length implements NDPOption.Length. +func (o NDPSourceLinkLayerAddressOption) Length() int { + return len(o) +} + +// serializeInto implements NDPOption.serializeInto. +func (o NDPSourceLinkLayerAddressOption) serializeInto(b []byte) int { + return copy(b, o) +} + +// EthernetAddress will return an ethernet (MAC) address if the +// NDPSourceLinkLayerAddressOption's body has at minimum EthernetAddressSize +// bytes. If the body has more than EthernetAddressSize bytes, only the first +// EthernetAddressSize bytes are returned as that is all that is needed for an +// Ethernet address. +func (o NDPSourceLinkLayerAddressOption) EthernetAddress() tcpip.LinkAddress { + if len(o) >= EthernetAddressSize { + return tcpip.LinkAddress(o[:EthernetAddressSize]) + } + + return tcpip.LinkAddress([]byte(nil)) +} + // NDPTargetLinkLayerAddressOption is the NDP Target Link Layer Option // as defined by RFC 4861 section 4.6.1. // diff --git a/pkg/tcpip/header/ndp_test.go b/pkg/tcpip/header/ndp_test.go index 2c439d70c..1cb9f5dc8 100644 --- a/pkg/tcpip/header/ndp_test.go +++ b/pkg/tcpip/header/ndp_test.go @@ -153,6 +153,125 @@ func TestNDPRouterAdvert(t *testing.T) { } } +// TestNDPSourceLinkLayerAddressOptionEthernetAddress tests getting the +// Ethernet address from an NDPSourceLinkLayerAddressOption. +func TestNDPSourceLinkLayerAddressOptionEthernetAddress(t *testing.T) { + tests := []struct { + name string + buf []byte + expected tcpip.LinkAddress + }{ + { + "ValidMAC", + []byte{1, 2, 3, 4, 5, 6}, + tcpip.LinkAddress("\x01\x02\x03\x04\x05\x06"), + }, + { + "SLLBodyTooShort", + []byte{1, 2, 3, 4, 5}, + tcpip.LinkAddress([]byte(nil)), + }, + { + "SLLBodyLargerThanNeeded", + []byte{1, 2, 3, 4, 5, 6, 7, 8}, + tcpip.LinkAddress("\x01\x02\x03\x04\x05\x06"), + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + sll := NDPSourceLinkLayerAddressOption(test.buf) + if got := sll.EthernetAddress(); got != test.expected { + t.Errorf("got sll.EthernetAddress = %s, want = %s", got, test.expected) + } + }) + } +} + +// TestNDPSourceLinkLayerAddressOptionSerialize tests serializing a +// NDPSourceLinkLayerAddressOption. +func TestNDPSourceLinkLayerAddressOptionSerialize(t *testing.T) { + tests := []struct { + name string + buf []byte + expectedBuf []byte + addr tcpip.LinkAddress + }{ + { + "Ethernet", + make([]byte, 8), + []byte{1, 1, 1, 2, 3, 4, 5, 6}, + "\x01\x02\x03\x04\x05\x06", + }, + { + "Padding", + []byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, + []byte{1, 2, 1, 2, 3, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0}, + "\x01\x02\x03\x04\x05\x06\x07\x08", + }, + { + "Empty", + nil, + nil, + "", + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + opts := NDPOptions(test.buf) + serializer := NDPOptionsSerializer{ + NDPSourceLinkLayerAddressOption(test.addr), + } + if got, want := int(serializer.Length()), len(test.expectedBuf); got != want { + t.Fatalf("got Length = %d, want = %d", got, want) + } + opts.Serialize(serializer) + if !bytes.Equal(test.buf, test.expectedBuf) { + t.Fatalf("got b = %d, want = %d", test.buf, test.expectedBuf) + } + + it, err := opts.Iter(true) + if err != nil { + t.Fatalf("got Iter = (_, %s), want = (_, nil)", err) + } + + if len(test.expectedBuf) > 0 { + next, done, err := it.Next() + if err != nil { + t.Fatalf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if done { + t.Fatal("got Next = (_, true, _), want = (_, false, _)") + } + if got := next.Type(); got != NDPSourceLinkLayerAddressOptionType { + t.Fatalf("got Type = %d, want = %d", got, NDPSourceLinkLayerAddressOptionType) + } + sll := next.(NDPSourceLinkLayerAddressOption) + if got, want := []byte(sll), test.expectedBuf[2:]; !bytes.Equal(got, want) { + t.Fatalf("got Next = (%x, _, _), want = (%x, _, _)", got, want) + } + + if got, want := sll.EthernetAddress(), tcpip.LinkAddress(test.expectedBuf[2:][:EthernetAddressSize]); got != want { + t.Errorf("got sll.EthernetAddress = %s, want = %s", got, want) + } + } + + // Iterator should not return anything else. + next, done, err := it.Next() + if err != nil { + t.Errorf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if !done { + t.Error("got Next = (_, false, _), want = (_, true, _)") + } + if next != nil { + t.Errorf("got Next = (%x, _, _), want = (nil, _, _)", next) + } + }) + } +} + // TestNDPTargetLinkLayerAddressOptionEthernetAddress tests getting the // Ethernet address from an NDPTargetLinkLayerAddressOption. func TestNDPTargetLinkLayerAddressOptionEthernetAddress(t *testing.T) { @@ -186,7 +305,6 @@ func TestNDPTargetLinkLayerAddressOptionEthernetAddress(t *testing.T) { } }) } - } // TestNDPTargetLinkLayerAddressOptionSerialize tests serializing a @@ -212,8 +330,8 @@ func TestNDPTargetLinkLayerAddressOptionSerialize(t *testing.T) { }, { "Empty", - []byte{}, - []byte{}, + nil, + nil, "", }, } @@ -246,7 +364,7 @@ func TestNDPTargetLinkLayerAddressOptionSerialize(t *testing.T) { t.Fatal("got Next = (_, true, _), want = (_, false, _)") } if got := next.Type(); got != NDPTargetLinkLayerAddressOptionType { - t.Fatalf("got Type %= %d, want = %d", got, NDPTargetLinkLayerAddressOptionType) + t.Fatalf("got Type = %d, want = %d", got, NDPTargetLinkLayerAddressOptionType) } tll := next.(NDPTargetLinkLayerAddressOption) if got, want := []byte(tll), test.expectedBuf[2:]; !bytes.Equal(got, want) { @@ -254,7 +372,7 @@ func TestNDPTargetLinkLayerAddressOptionSerialize(t *testing.T) { } if got, want := tll.EthernetAddress(), tcpip.LinkAddress(test.expectedBuf[2:][:EthernetAddressSize]); got != want { - t.Errorf("got tll.MACAddress = %s, want = %s", got, want) + t.Errorf("got tll.EthernetAddress = %s, want = %s", got, want) } } @@ -510,7 +628,7 @@ func TestNDPRecursiveDNSServerOption(t *testing.T) { t.Fatal("got Next = (_, true, _), want = (_, false, _)") } if got := next.Type(); got != NDPRecursiveDNSServerOptionType { - t.Fatalf("got Type %= %d, want = %d", got, NDPRecursiveDNSServerOptionType) + t.Fatalf("got Type = %d, want = %d", got, NDPRecursiveDNSServerOptionType) } opt, ok := next.(NDPRecursiveDNSServer) @@ -552,6 +670,16 @@ func TestNDPOptionsIterCheck(t *testing.T) { []byte{0, 0, 0, 0, 0, 0, 0, 0}, ErrNDPOptZeroLength, }, + { + "ValidSourceLinkLayerAddressOption", + []byte{1, 1, 1, 2, 3, 4, 5, 6}, + nil, + }, + { + "TooSmallSourceLinkLayerAddressOption", + []byte{1, 1, 1, 2, 3, 4, 5}, + ErrNDPOptBufExhausted, + }, { "ValidTargetLinkLayerAddressOption", []byte{2, 1, 1, 2, 3, 4, 5, 6}, @@ -603,10 +731,13 @@ func TestNDPOptionsIterCheck(t *testing.T) { ErrNDPOptMalformedBody, }, { - "ValidTargetLinkLayerAddressWithPrefixInformation", + "ValidSourceAndTargetLinkLayerAddressWithPrefixInformation", []byte{ + // Source Link-Layer Address. + 1, 1, 1, 2, 3, 4, 5, 6, + // Target Link-Layer Address. - 2, 1, 1, 2, 3, 4, 5, 6, + 2, 1, 7, 8, 9, 10, 11, 12, // Prefix information. 3, 4, 43, 64, @@ -621,10 +752,13 @@ func TestNDPOptionsIterCheck(t *testing.T) { nil, }, { - "ValidTargetLinkLayerAddressWithPrefixInformationWithUnrecognized", + "ValidSourceAndTargetLinkLayerAddressWithPrefixInformationWithUnrecognized", []byte{ + // Source Link-Layer Address. + 1, 1, 1, 2, 3, 4, 5, 6, + // Target Link-Layer Address. - 2, 1, 1, 2, 3, 4, 5, 6, + 2, 1, 7, 8, 9, 10, 11, 12, // 255 is an unrecognized type. If 255 ends up // being the type for some recognized type, @@ -714,8 +848,11 @@ func TestNDPOptionsIterCheck(t *testing.T) { // here. func TestNDPOptionsIter(t *testing.T) { buf := []byte{ + // Source Link-Layer Address. + 1, 1, 1, 2, 3, 4, 5, 6, + // Target Link-Layer Address. - 2, 1, 1, 2, 3, 4, 5, 6, + 2, 1, 7, 8, 9, 10, 11, 12, // 255 is an unrecognized type. If 255 ends up being the type // for some recognized type, update 255 to some other @@ -740,7 +877,7 @@ func TestNDPOptionsIter(t *testing.T) { t.Fatalf("got Iter = (_, %s), want = (_, nil)", err) } - // Test the first (Taret Link-Layer) option. + // Test the first (Source Link-Layer) option. next, done, err := it.Next() if err != nil { t.Fatalf("got Next = (_, _, %s), want = (_, _, nil)", err) @@ -748,7 +885,22 @@ func TestNDPOptionsIter(t *testing.T) { if done { t.Fatal("got Next = (_, true, _), want = (_, false, _)") } - if got, want := []byte(next.(NDPTargetLinkLayerAddressOption)), buf[2:][:6]; !bytes.Equal(got, want) { + if got, want := []byte(next.(NDPSourceLinkLayerAddressOption)), buf[2:][:6]; !bytes.Equal(got, want) { + t.Errorf("got Next = (%x, _, _), want = (%x, _, _)", got, want) + } + if got := next.Type(); got != NDPSourceLinkLayerAddressOptionType { + t.Errorf("got Type = %d, want = %d", got, NDPSourceLinkLayerAddressOptionType) + } + + // Test the next (Target Link-Layer) option. + next, done, err = it.Next() + if err != nil { + t.Fatalf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if done { + t.Fatal("got Next = (_, true, _), want = (_, false, _)") + } + if got, want := []byte(next.(NDPTargetLinkLayerAddressOption)), buf[10:][:6]; !bytes.Equal(got, want) { t.Errorf("got Next = (%x, _, _), want = (%x, _, _)", got, want) } if got := next.Type(); got != NDPTargetLinkLayerAddressOptionType { @@ -764,7 +916,7 @@ func TestNDPOptionsIter(t *testing.T) { if done { t.Fatal("got Next = (_, true, _), want = (_, false, _)") } - if got, want := next.(NDPPrefixInformation), buf[26:][:30]; !bytes.Equal(got, want) { + if got, want := next.(NDPPrefixInformation), buf[34:][:30]; !bytes.Equal(got, want) { t.Errorf("got Next = (%x, _, _), want = (%x, _, _)", got, want) } if got := next.Type(); got != NDPPrefixInformationType { -- cgit v1.2.3 From ce0bac4be9d808877248c328fac07ff0d66b9607 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Tue, 28 Jan 2020 13:37:10 -0800 Subject: Include the NDP Source Link Layer option when sending DAD messages Test: stack_test.TestDADResolve PiperOrigin-RevId: 292003124 --- pkg/tcpip/checker/checker.go | 50 +++++++++++++++++++++++++++++++++++++++++ pkg/tcpip/header/icmpv6.go | 2 +- pkg/tcpip/header/ndp_options.go | 35 ++++++++++++++++++++++++++--- pkg/tcpip/stack/ndp.go | 22 ++++++++++++++++-- pkg/tcpip/stack/ndp_test.go | 6 ++++- 5 files changed, 108 insertions(+), 7 deletions(-) (limited to 'pkg/tcpip/header/ndp_options.go') diff --git a/pkg/tcpip/checker/checker.go b/pkg/tcpip/checker/checker.go index 885d773b0..4d6ae0871 100644 --- a/pkg/tcpip/checker/checker.go +++ b/pkg/tcpip/checker/checker.go @@ -771,6 +771,56 @@ func NDPNSTargetAddress(want tcpip.Address) TransportChecker { } } +// NDPNSOptions creates a checker that checks that the packet contains the +// provided NDP options within an NDP Neighbor Solicitation message. +// +// The returned TransportChecker assumes that a valid ICMPv6 is passed to it +// containing a valid NDPNS message as far as the size is concerned. +func NDPNSOptions(opts []header.NDPOption) TransportChecker { + return func(t *testing.T, h header.Transport) { + t.Helper() + + icmp := h.(header.ICMPv6) + ns := header.NDPNeighborSolicit(icmp.NDPPayload()) + it, err := ns.Options().Iter(true) + if err != nil { + t.Errorf("opts.Iter(true): %s", err) + return + } + + i := 0 + for { + opt, done, _ := it.Next() + if done { + break + } + + if i >= len(opts) { + t.Errorf("got unexpected option: %s", opt) + continue + } + + switch wantOpt := opts[i].(type) { + case header.NDPSourceLinkLayerAddressOption: + gotOpt, ok := opt.(header.NDPSourceLinkLayerAddressOption) + if !ok { + t.Errorf("got type = %T at index = %d; want = %T", opt, i, wantOpt) + } else if got, want := gotOpt.EthernetAddress(), wantOpt.EthernetAddress(); got != want { + t.Errorf("got EthernetAddress() = %s at index %d, want = %s", got, i, want) + } + default: + panic("not implemented") + } + + i++ + } + + if missing := opts[i:]; len(missing) > 0 { + t.Errorf("missing options: %s", missing) + } + } +} + // NDPRS creates a checker that checks that the packet contains a valid NDP // Router Solicitation message (as per the raw wire format). func NDPRS() NetworkChecker { diff --git a/pkg/tcpip/header/icmpv6.go b/pkg/tcpip/header/icmpv6.go index b095dc0ab..c7ee2de57 100644 --- a/pkg/tcpip/header/icmpv6.go +++ b/pkg/tcpip/header/icmpv6.go @@ -52,7 +52,7 @@ const ( // ICMPv6NeighborAdvertSize is size of a neighbor advertisement // including the NDP Target Link Layer option for an Ethernet // address. - ICMPv6NeighborAdvertSize = ICMPv6HeaderSize + NDPNAMinimumSize + ndpLinkLayerAddressSize + ICMPv6NeighborAdvertSize = ICMPv6HeaderSize + NDPNAMinimumSize + NDPLinkLayerAddressSize // ICMPv6EchoMinimumSize is the minimum size of a valid ICMP echo packet. ICMPv6EchoMinimumSize = 8 diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go index 1e60f3d4f..e6a6ad39b 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -17,6 +17,7 @@ package header import ( "encoding/binary" "errors" + "fmt" "math" "time" @@ -32,9 +33,9 @@ const ( // Address option, as per RFC 4861 section 4.6.1. NDPTargetLinkLayerAddressOptionType = 2 - // ndpLinkLayerAddressSize is the size of a Source or Target Link Layer - // Address option. - ndpLinkLayerAddressSize = 8 + // NDPLinkLayerAddressSize is the size of a Source or Target Link Layer + // Address option for an Ethernet address. + NDPLinkLayerAddressSize = 8 // NDPPrefixInformationType is the type of the Prefix Information // option, as per RFC 4861 section 4.6.2. @@ -300,6 +301,8 @@ func (b NDPOptions) Serialize(s NDPOptionsSerializer) int { // NDPOption is the set of functions to be implemented by all NDP option types. type NDPOption interface { + fmt.Stringer + // Type returns the type of the receiver. Type() uint8 @@ -397,6 +400,11 @@ func (o NDPSourceLinkLayerAddressOption) serializeInto(b []byte) int { return copy(b, o) } +// String implements fmt.Stringer.String. +func (o NDPSourceLinkLayerAddressOption) String() string { + return fmt.Sprintf("%T(%s)", o, tcpip.LinkAddress(o)) +} + // EthernetAddress will return an ethernet (MAC) address if the // NDPSourceLinkLayerAddressOption's body has at minimum EthernetAddressSize // bytes. If the body has more than EthernetAddressSize bytes, only the first @@ -432,6 +440,11 @@ func (o NDPTargetLinkLayerAddressOption) serializeInto(b []byte) int { return copy(b, o) } +// String implements fmt.Stringer.String. +func (o NDPTargetLinkLayerAddressOption) String() string { + return fmt.Sprintf("%T(%s)", o, tcpip.LinkAddress(o)) +} + // EthernetAddress will return an ethernet (MAC) address if the // NDPTargetLinkLayerAddressOption's body has at minimum EthernetAddressSize // bytes. If the body has more than EthernetAddressSize bytes, only the first @@ -478,6 +491,17 @@ func (o NDPPrefixInformation) serializeInto(b []byte) int { return used } +// String implements fmt.Stringer.String. +func (o NDPPrefixInformation) String() string { + return fmt.Sprintf("%T(O=%t, A=%t, PL=%s, VL=%s, Prefix=%s)", + o, + o.OnLinkFlag(), + o.AutonomousAddressConfigurationFlag(), + o.PreferredLifetime(), + o.ValidLifetime(), + o.Subnet()) +} + // PrefixLength returns the value in the number of leading bits in the Prefix // that are valid. // @@ -587,6 +611,11 @@ func (o NDPRecursiveDNSServer) serializeInto(b []byte) int { return used } +// String implements fmt.Stringer.String. +func (o NDPRecursiveDNSServer) String() string { + return fmt.Sprintf("%T(%s valid for %s)", o, o.Addresses(), o.Lifetime()) +} + // Lifetime returns the length of time that the DNS server addresses // in this option may be used for name resolution. // diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index d983ac390..245694118 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -538,11 +538,29 @@ func (ndp *ndpState) sendDADPacket(addr tcpip.Address) *tcpip.Error { r := makeRoute(header.IPv6ProtocolNumber, header.IPv6Any, snmc, ndp.nic.linkEP.LinkAddress(), ref, false, false) defer r.Release() - hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv6NeighborSolicitMinimumSize) - pkt := header.ICMPv6(hdr.Prepend(header.ICMPv6NeighborSolicitMinimumSize)) + linkAddr := ndp.nic.linkEP.LinkAddress() + isValidLinkAddr := header.IsValidUnicastEthernetAddress(linkAddr) + ndpNSSize := header.ICMPv6NeighborSolicitMinimumSize + if isValidLinkAddr { + // Only include a Source Link Layer Address option if the NIC has a valid + // link layer address. + // + // TODO(b/141011931): Validate a LinkEndpoint's link address (provided by + // LinkEndpoint.LinkAddress) before reaching this point. + ndpNSSize += header.NDPLinkLayerAddressSize + } + + hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + ndpNSSize) + pkt := header.ICMPv6(hdr.Prepend(ndpNSSize)) pkt.SetType(header.ICMPv6NeighborSolicit) ns := header.NDPNeighborSolicit(pkt.NDPPayload()) ns.SetTargetAddress(addr) + + if isValidLinkAddr { + ns.Options().Serialize(header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(linkAddr), + }) + } pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{})) sent := r.Stats().ICMP.V6PacketsSent diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go index ad2c6f601..726468e41 100644 --- a/pkg/tcpip/stack/ndp_test.go +++ b/pkg/tcpip/stack/ndp_test.go @@ -417,7 +417,11 @@ func TestDADResolve(t *testing.T) { checker.IPv6(t, p.Pkt.Header.View().ToVectorisedView().First(), checker.TTL(header.NDPHopLimit), checker.NDPNS( - checker.NDPNSTargetAddress(addr1))) + checker.NDPNSTargetAddress(addr1), + checker.NDPNSOptions([]header.NDPOption{ + header.NDPSourceLinkLayerAddressOption(linkAddr1), + }), + )) } }) } -- cgit v1.2.3 From b33c3bb4a73974bbae4274da5100a3cd3f5deef8 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Thu, 16 Apr 2020 17:26:12 -0700 Subject: Return detailed errors when iterating NDP options Test: header_test.TestNDPOptionsIterCheck PiperOrigin-RevId: 306953867 --- pkg/tcpip/header/BUILD | 1 + pkg/tcpip/header/ndp_options.go | 196 ++++++++++++++----------- pkg/tcpip/header/ndp_test.go | 118 ++++++++------- pkg/tcpip/header/ndpoptionidentifier_string.go | 50 +++++++ pkg/tcpip/stack/ndp.go | 3 +- 5 files changed, 228 insertions(+), 140 deletions(-) create mode 100644 pkg/tcpip/header/ndpoptionidentifier_string.go (limited to 'pkg/tcpip/header/ndp_options.go') diff --git a/pkg/tcpip/header/BUILD b/pkg/tcpip/header/BUILD index 7094f3f0b..0cde694dc 100644 --- a/pkg/tcpip/header/BUILD +++ b/pkg/tcpip/header/BUILD @@ -21,6 +21,7 @@ go_library( "ndp_options.go", "ndp_router_advert.go", "ndp_router_solicit.go", + "ndpoptionidentifier_string.go", "tcp.go", "udp.go", ], diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go index e6a6ad39b..444e90820 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -15,32 +15,43 @@ package header import ( + "bytes" "encoding/binary" "errors" "fmt" + "io" "math" "time" "gvisor.dev/gvisor/pkg/tcpip" ) +// NDPOptionIdentifier is an NDP option type identifier. +type NDPOptionIdentifier uint8 + const ( // NDPSourceLinkLayerAddressOptionType is the type of the Source Link Layer // Address option, as per RFC 4861 section 4.6.1. - NDPSourceLinkLayerAddressOptionType = 1 + NDPSourceLinkLayerAddressOptionType NDPOptionIdentifier = 1 // NDPTargetLinkLayerAddressOptionType is the type of the Target Link Layer // Address option, as per RFC 4861 section 4.6.1. - NDPTargetLinkLayerAddressOptionType = 2 + NDPTargetLinkLayerAddressOptionType NDPOptionIdentifier = 2 + + // NDPPrefixInformationType is the type of the Prefix Information + // option, as per RFC 4861 section 4.6.2. + NDPPrefixInformationType NDPOptionIdentifier = 3 + + // NDPRecursiveDNSServerOptionType is the type of the Recursive DNS + // Server option, as per RFC 8106 section 5.1. + NDPRecursiveDNSServerOptionType NDPOptionIdentifier = 25 +) +const ( // NDPLinkLayerAddressSize is the size of a Source or Target Link Layer // Address option for an Ethernet address. NDPLinkLayerAddressSize = 8 - // NDPPrefixInformationType is the type of the Prefix Information - // option, as per RFC 4861 section 4.6.2. - NDPPrefixInformationType = 3 - // ndpPrefixInformationLength is the expected length, in bytes, of the // body of an NDP Prefix Information option, as per RFC 4861 section // 4.6.2 which specifies that the Length field is 4. Given this, the @@ -91,10 +102,6 @@ const ( // within an NDPPrefixInformation. ndpPrefixInformationPrefixOffset = 14 - // NDPRecursiveDNSServerOptionType is the type of the Recursive DNS - // Server option, as per RFC 8106 section 5.1. - NDPRecursiveDNSServerOptionType = 25 - // ndpRecursiveDNSServerLifetimeOffset is the start of the 4-byte // Lifetime field within an NDPRecursiveDNSServer. ndpRecursiveDNSServerLifetimeOffset = 2 @@ -103,10 +110,10 @@ const ( // for IPv6 Recursive DNS Servers within an NDPRecursiveDNSServer. ndpRecursiveDNSServerAddressesOffset = 6 - // minNDPRecursiveDNSServerLength is the minimum NDP Recursive DNS - // Server option's length field value when it contains at least one - // IPv6 address. - minNDPRecursiveDNSServerLength = 3 + // minNDPRecursiveDNSServerLength is the minimum NDP Recursive DNS Server + // option's body size when it contains at least one IPv6 address, as per + // RFC 8106 section 5.3.1. + minNDPRecursiveDNSServerBodySize = 22 // lengthByteUnits is the multiplier factor for the Length field of an // NDP option. That is, the length field for NDP options is in units of @@ -132,16 +139,13 @@ var ( // few NDPOption then modify the backing NDPOptions so long as the // NDPOptionIterator obtained before modification is no longer used. type NDPOptionIterator struct { - // The NDPOptions this NDPOptionIterator is iterating over. - opts NDPOptions + opts *bytes.Buffer } // Potential errors when iterating over an NDPOptions. var ( - ErrNDPOptBufExhausted = errors.New("Buffer unexpectedly exhausted") - ErrNDPOptZeroLength = errors.New("NDP option has zero-valued Length field") - ErrNDPOptMalformedBody = errors.New("NDP option has a malformed body") - ErrNDPInvalidLength = errors.New("NDP option's Length value is invalid as per relevant RFC") + ErrNDPOptMalformedBody = errors.New("NDP option has a malformed body") + ErrNDPOptMalformedHeader = errors.New("NDP option has a malformed header") ) // Next returns the next element in the backing NDPOptions, or true if we are @@ -152,48 +156,50 @@ var ( func (i *NDPOptionIterator) Next() (NDPOption, bool, error) { for { // Do we still have elements to look at? - if len(i.opts) == 0 { + if i.opts.Len() == 0 { return nil, true, nil } - // Do we have enough bytes for an NDP option that has a Length - // field of at least 1? Note, 0 in the Length field is invalid. - if len(i.opts) < lengthByteUnits { - return nil, true, ErrNDPOptBufExhausted - } - // Get the Type field. - t := i.opts[0] - - // Get the Length field. - l := i.opts[1] + temp, err := i.opts.ReadByte() + if err != nil { + if err != io.EOF { + // ReadByte should only ever return nil or io.EOF. + panic(fmt.Sprintf("unexpected error when reading the option's Type field: %s", err)) + } - // This would indicate an erroneous NDP option as the Length - // field should never be 0. - if l == 0 { - return nil, true, ErrNDPOptZeroLength + // We use io.ErrUnexpectedEOF as exhausting the buffer is unexpected once + // we start parsing an option; we expect the buffer to contain enough + // bytes for the whole option. + return nil, true, fmt.Errorf("unexpectedly exhausted buffer when reading the option's Type field: %w", io.ErrUnexpectedEOF) } + kind := NDPOptionIdentifier(temp) - // How many bytes are in the option body? - numBytes := int(l) * lengthByteUnits - numBodyBytes := numBytes - 2 - - potentialBody := i.opts[2:] + // Get the Length field. + length, err := i.opts.ReadByte() + if err != nil { + if err != io.EOF { + panic(fmt.Sprintf("unexpected error when reading the option's Length field for %s: %s", kind, err)) + } - // This would indicate an erroenous NDPOptions buffer as we ran - // out of the buffer in the middle of an NDP option. - if left := len(potentialBody); left < numBodyBytes { - return nil, true, ErrNDPOptBufExhausted + return nil, true, fmt.Errorf("unexpectedly exhausted buffer when reading the option's Length field for %s: %w", kind, io.ErrUnexpectedEOF) } - // Get only the options body, leaving the rest of the options - // buffer alone. - body := potentialBody[:numBodyBytes] + // This would indicate an erroneous NDP option as the Length field should + // never be 0. + if length == 0 { + return nil, true, fmt.Errorf("zero valued Length field for %s: %w", kind, ErrNDPOptMalformedHeader) + } - // Update opts with the remaining options body. - i.opts = i.opts[numBytes:] + // Get the body. + numBytes := int(length) * lengthByteUnits + numBodyBytes := numBytes - 2 + body := i.opts.Next(numBodyBytes) + if len(body) < numBodyBytes { + return nil, true, fmt.Errorf("unexpectedly exhausted buffer when reading the option's Body for %s: %w", kind, io.ErrUnexpectedEOF) + } - switch t { + switch kind { case NDPSourceLinkLayerAddressOptionType: return NDPSourceLinkLayerAddressOption(body), false, nil @@ -205,22 +211,15 @@ func (i *NDPOptionIterator) Next() (NDPOption, bool, error) { // body is ndpPrefixInformationLength, as per RFC 4861 // section 4.6.2. if numBodyBytes != ndpPrefixInformationLength { - return nil, true, ErrNDPOptMalformedBody + return nil, true, fmt.Errorf("got %d bytes for NDP Prefix Information option's body, expected %d bytes: %w", numBodyBytes, ndpPrefixInformationLength, ErrNDPOptMalformedBody) } return NDPPrefixInformation(body), false, nil case NDPRecursiveDNSServerOptionType: - // RFC 8106 section 5.3.1 outlines that the RDNSS option - // must have a minimum length of 3 so it contains at - // least one IPv6 address. - if l < minNDPRecursiveDNSServerLength { - return nil, true, ErrNDPInvalidLength - } - opt := NDPRecursiveDNSServer(body) - if len(opt.Addresses()) == 0 { - return nil, true, ErrNDPOptMalformedBody + if err := opt.checkAddresses(); err != nil { + return nil, true, err } return opt, false, nil @@ -247,10 +246,16 @@ type NDPOptions []byte // // See NDPOptionIterator for more information. func (b NDPOptions) Iter(check bool) (NDPOptionIterator, error) { - it := NDPOptionIterator{opts: b} + it := NDPOptionIterator{ + opts: bytes.NewBuffer(b), + } if check { - for it2 := it; true; { + it2 := NDPOptionIterator{ + opts: bytes.NewBuffer(b), + } + + for { if _, done, err := it2.Next(); err != nil || done { return it, err } @@ -278,7 +283,7 @@ func (b NDPOptions) Serialize(s NDPOptionsSerializer) int { continue } - b[0] = o.Type() + b[0] = byte(o.Type()) // We know this safe because paddedLength would have returned // 0 if o had an invalid length (> 255 * lengthByteUnits). @@ -304,7 +309,7 @@ type NDPOption interface { fmt.Stringer // Type returns the type of the receiver. - Type() uint8 + Type() NDPOptionIdentifier // Length returns the length of the body of the receiver, in bytes. Length() int @@ -386,7 +391,7 @@ func (b NDPOptionsSerializer) Length() int { type NDPSourceLinkLayerAddressOption tcpip.LinkAddress // Type implements NDPOption.Type. -func (o NDPSourceLinkLayerAddressOption) Type() uint8 { +func (o NDPSourceLinkLayerAddressOption) Type() NDPOptionIdentifier { return NDPSourceLinkLayerAddressOptionType } @@ -426,7 +431,7 @@ func (o NDPSourceLinkLayerAddressOption) EthernetAddress() tcpip.LinkAddress { type NDPTargetLinkLayerAddressOption tcpip.LinkAddress // Type implements NDPOption.Type. -func (o NDPTargetLinkLayerAddressOption) Type() uint8 { +func (o NDPTargetLinkLayerAddressOption) Type() NDPOptionIdentifier { return NDPTargetLinkLayerAddressOptionType } @@ -466,7 +471,7 @@ func (o NDPTargetLinkLayerAddressOption) EthernetAddress() tcpip.LinkAddress { type NDPPrefixInformation []byte // Type implements NDPOption.Type. -func (o NDPPrefixInformation) Type() uint8 { +func (o NDPPrefixInformation) Type() NDPOptionIdentifier { return NDPPrefixInformationType } @@ -590,7 +595,7 @@ type NDPRecursiveDNSServer []byte // Type returns the type of an NDP Recursive DNS Server option. // // Type implements NDPOption.Type. -func (NDPRecursiveDNSServer) Type() uint8 { +func (NDPRecursiveDNSServer) Type() NDPOptionIdentifier { return NDPRecursiveDNSServerOptionType } @@ -613,7 +618,12 @@ func (o NDPRecursiveDNSServer) serializeInto(b []byte) int { // String implements fmt.Stringer.String. func (o NDPRecursiveDNSServer) String() string { - return fmt.Sprintf("%T(%s valid for %s)", o, o.Addresses(), o.Lifetime()) + lt := o.Lifetime() + addrs, err := o.Addresses() + if err != nil { + return fmt.Sprintf("%T([] valid for %s; err = %s)", o, lt, err) + } + return fmt.Sprintf("%T(%s valid for %s)", o, addrs, lt) } // Lifetime returns the length of time that the DNS server addresses @@ -632,29 +642,45 @@ func (o NDPRecursiveDNSServer) Lifetime() time.Duration { // Addresses returns the recursive DNS server IPv6 addresses that may be // used for name resolution. // -// Note, some of the addresses returned MAY be link-local addresses. +// Note, the addresses MAY be link-local addresses. +func (o NDPRecursiveDNSServer) Addresses() ([]tcpip.Address, error) { + var addrs []tcpip.Address + return addrs, o.iterAddresses(func(addr tcpip.Address) { addrs = append(addrs, addr) }) +} + +// checkAddresses iterates over the addresses in an NDP Recursive DNS Server +// option and returns any error it encounters. +func (o NDPRecursiveDNSServer) checkAddresses() error { + return o.iterAddresses(nil) +} + +// iterAddresses iterates over the addresses in an NDP Recursive DNS Server +// option and calls a function with each valid unicast IPv6 address. // -// Addresses may panic if o does not hold valid IPv6 addresses. -func (o NDPRecursiveDNSServer) Addresses() []tcpip.Address { - l := len(o) - if l < ndpRecursiveDNSServerAddressesOffset { - return nil +// Note, the addresses MAY be link-local addresses. +func (o NDPRecursiveDNSServer) iterAddresses(fn func(tcpip.Address)) error { + if l := len(o); l < minNDPRecursiveDNSServerBodySize { + return fmt.Errorf("got %d bytes for NDP Recursive DNS Server option's body, expected at least %d bytes: %w", l, minNDPRecursiveDNSServerBodySize, io.ErrUnexpectedEOF) } - l -= ndpRecursiveDNSServerAddressesOffset + o = o[ndpRecursiveDNSServerAddressesOffset:] + l := len(o) if l%IPv6AddressSize != 0 { - return nil + return fmt.Errorf("NDP Recursive DNS Server option's body ends in the middle of an IPv6 address (addresses body size = %d bytes): %w", l, ErrNDPOptMalformedBody) } - buf := o[ndpRecursiveDNSServerAddressesOffset:] - var addrs []tcpip.Address - for len(buf) > 0 { - addr := tcpip.Address(buf[:IPv6AddressSize]) + for i := 0; len(o) != 0; i++ { + addr := tcpip.Address(o[:IPv6AddressSize]) if !IsV6UnicastAddress(addr) { - return nil + return fmt.Errorf("%d-th address (%s) in NDP Recursive DNS Server option is not a valid unicast IPv6 address: %w", i, addr, ErrNDPOptMalformedBody) + } + + if fn != nil { + fn(addr) } - addrs = append(addrs, addr) - buf = buf[IPv6AddressSize:] + + o = o[IPv6AddressSize:] } - return addrs + + return nil } diff --git a/pkg/tcpip/header/ndp_test.go b/pkg/tcpip/header/ndp_test.go index 969f8f1e8..2341329c4 100644 --- a/pkg/tcpip/header/ndp_test.go +++ b/pkg/tcpip/header/ndp_test.go @@ -16,6 +16,8 @@ package header import ( "bytes" + "errors" + "io" "testing" "time" @@ -543,8 +545,12 @@ func TestNDPRecursiveDNSServerOptionSerialize(t *testing.T) { want := []tcpip.Address{ "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f", } - if got := opt.Addresses(); !cmp.Equal(got, want) { - t.Errorf("got Addresses = %v, want = %v", got, want) + addrs, err := opt.Addresses() + if err != nil { + t.Errorf("opt.Addresses() = %s", err) + } + if diff := cmp.Diff(addrs, want); diff != "" { + t.Errorf("mismatched addresses (-want +got):\n%s", diff) } // Iterator should not return anything else. @@ -638,8 +644,12 @@ func TestNDPRecursiveDNSServerOption(t *testing.T) { if got := opt.Lifetime(); got != test.lifetime { t.Errorf("got Lifetime = %d, want = %d", got, test.lifetime) } - if got := opt.Addresses(); !cmp.Equal(got, test.addrs) { - t.Errorf("got Addresses = %v, want = %v", got, test.addrs) + addrs, err := opt.Addresses() + if err != nil { + t.Errorf("opt.Addresses() = %s", err) + } + if diff := cmp.Diff(addrs, test.addrs); diff != "" { + t.Errorf("mismatched addresses (-want +got):\n%s", diff) } // Iterator should not return anything else. @@ -661,38 +671,38 @@ func TestNDPRecursiveDNSServerOption(t *testing.T) { // the iterator was returned for is malformed. func TestNDPOptionsIterCheck(t *testing.T) { tests := []struct { - name string - buf []byte - expected error + name string + buf []byte + expectedErr error }{ { - "ZeroLengthField", - []byte{0, 0, 0, 0, 0, 0, 0, 0}, - ErrNDPOptZeroLength, + name: "ZeroLengthField", + buf: []byte{0, 0, 0, 0, 0, 0, 0, 0}, + expectedErr: ErrNDPOptMalformedHeader, }, { - "ValidSourceLinkLayerAddressOption", - []byte{1, 1, 1, 2, 3, 4, 5, 6}, - nil, + name: "ValidSourceLinkLayerAddressOption", + buf: []byte{1, 1, 1, 2, 3, 4, 5, 6}, + expectedErr: nil, }, { - "TooSmallSourceLinkLayerAddressOption", - []byte{1, 1, 1, 2, 3, 4, 5}, - ErrNDPOptBufExhausted, + name: "TooSmallSourceLinkLayerAddressOption", + buf: []byte{1, 1, 1, 2, 3, 4, 5}, + expectedErr: io.ErrUnexpectedEOF, }, { - "ValidTargetLinkLayerAddressOption", - []byte{2, 1, 1, 2, 3, 4, 5, 6}, - nil, + name: "ValidTargetLinkLayerAddressOption", + buf: []byte{2, 1, 1, 2, 3, 4, 5, 6}, + expectedErr: nil, }, { - "TooSmallTargetLinkLayerAddressOption", - []byte{2, 1, 1, 2, 3, 4, 5}, - ErrNDPOptBufExhausted, + name: "TooSmallTargetLinkLayerAddressOption", + buf: []byte{2, 1, 1, 2, 3, 4, 5}, + expectedErr: io.ErrUnexpectedEOF, }, { - "ValidPrefixInformation", - []byte{ + name: "ValidPrefixInformation", + buf: []byte{ 3, 4, 43, 64, 1, 2, 3, 4, 5, 6, 7, 8, @@ -702,11 +712,11 @@ func TestNDPOptionsIterCheck(t *testing.T) { 17, 18, 19, 20, 21, 22, 23, 24, }, - nil, + expectedErr: nil, }, { - "TooSmallPrefixInformation", - []byte{ + name: "TooSmallPrefixInformation", + buf: []byte{ 3, 4, 43, 64, 1, 2, 3, 4, 5, 6, 7, 8, @@ -716,11 +726,11 @@ func TestNDPOptionsIterCheck(t *testing.T) { 17, 18, 19, 20, 21, 22, 23, }, - ErrNDPOptBufExhausted, + expectedErr: io.ErrUnexpectedEOF, }, { - "InvalidPrefixInformationLength", - []byte{ + name: "InvalidPrefixInformationLength", + buf: []byte{ 3, 3, 43, 64, 1, 2, 3, 4, 5, 6, 7, 8, @@ -728,11 +738,11 @@ func TestNDPOptionsIterCheck(t *testing.T) { 9, 10, 11, 12, 13, 14, 15, 16, }, - ErrNDPOptMalformedBody, + expectedErr: ErrNDPOptMalformedBody, }, { - "ValidSourceAndTargetLinkLayerAddressWithPrefixInformation", - []byte{ + name: "ValidSourceAndTargetLinkLayerAddressWithPrefixInformation", + buf: []byte{ // Source Link-Layer Address. 1, 1, 1, 2, 3, 4, 5, 6, @@ -749,11 +759,11 @@ func TestNDPOptionsIterCheck(t *testing.T) { 17, 18, 19, 20, 21, 22, 23, 24, }, - nil, + expectedErr: nil, }, { - "ValidSourceAndTargetLinkLayerAddressWithPrefixInformationWithUnrecognized", - []byte{ + name: "ValidSourceAndTargetLinkLayerAddressWithPrefixInformationWithUnrecognized", + buf: []byte{ // Source Link-Layer Address. 1, 1, 1, 2, 3, 4, 5, 6, @@ -775,52 +785,52 @@ func TestNDPOptionsIterCheck(t *testing.T) { 17, 18, 19, 20, 21, 22, 23, 24, }, - nil, + expectedErr: nil, }, { - "InvalidRecursiveDNSServerCutsOffAddress", - []byte{ + name: "InvalidRecursiveDNSServerCutsOffAddress", + buf: []byte{ 25, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 2, 3, 4, 5, 6, 7, }, - ErrNDPOptMalformedBody, + expectedErr: ErrNDPOptMalformedBody, }, { - "InvalidRecursiveDNSServerInvalidLengthField", - []byte{ + name: "InvalidRecursiveDNSServerInvalidLengthField", + buf: []byte{ 25, 2, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, }, - ErrNDPInvalidLength, + expectedErr: io.ErrUnexpectedEOF, }, { - "RecursiveDNSServerTooSmall", - []byte{ + name: "RecursiveDNSServerTooSmall", + buf: []byte{ 25, 1, 0, 0, 0, 0, 0, }, - ErrNDPOptBufExhausted, + expectedErr: io.ErrUnexpectedEOF, }, { - "RecursiveDNSServerMulticast", - []byte{ + name: "RecursiveDNSServerMulticast", + buf: []byte{ 25, 3, 0, 0, 0, 0, 0, 0, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, }, - ErrNDPOptMalformedBody, + expectedErr: ErrNDPOptMalformedBody, }, { - "RecursiveDNSServerUnspecified", - []byte{ + name: "RecursiveDNSServerUnspecified", + buf: []byte{ 25, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, }, - ErrNDPOptMalformedBody, + expectedErr: ErrNDPOptMalformedBody, }, } @@ -828,8 +838,8 @@ func TestNDPOptionsIterCheck(t *testing.T) { t.Run(test.name, func(t *testing.T) { opts := NDPOptions(test.buf) - if _, err := opts.Iter(true); err != test.expected { - t.Fatalf("got Iter(true) = (_, %v), want = (_, %v)", err, test.expected) + if _, err := opts.Iter(true); !errors.Is(err, test.expectedErr) { + t.Fatalf("got Iter(true) = (_, %v), want = (_, %v)", err, test.expectedErr) } // test.buf may be malformed but we chose not to check diff --git a/pkg/tcpip/header/ndpoptionidentifier_string.go b/pkg/tcpip/header/ndpoptionidentifier_string.go new file mode 100644 index 000000000..6fe9a336b --- /dev/null +++ b/pkg/tcpip/header/ndpoptionidentifier_string.go @@ -0,0 +1,50 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Code generated by "stringer -type NDPOptionIdentifier ."; DO NOT EDIT. + +package header + +import "strconv" + +func _() { + // An "invalid array index" compiler error signifies that the constant values have changed. + // Re-run the stringer command to generate them again. + var x [1]struct{} + _ = x[NDPSourceLinkLayerAddressOptionType-1] + _ = x[NDPTargetLinkLayerAddressOptionType-2] + _ = x[NDPPrefixInformationType-3] + _ = x[NDPRecursiveDNSServerOptionType-25] +} + +const ( + _NDPOptionIdentifier_name_0 = "NDPSourceLinkLayerAddressOptionTypeNDPTargetLinkLayerAddressOptionTypeNDPPrefixInformationType" + _NDPOptionIdentifier_name_1 = "NDPRecursiveDNSServerOptionType" +) + +var ( + _NDPOptionIdentifier_index_0 = [...]uint8{0, 35, 70, 94} +) + +func (i NDPOptionIdentifier) String() string { + switch { + case 1 <= i && i <= 3: + i -= 1 + return _NDPOptionIdentifier_name_0[_NDPOptionIdentifier_index_0[i]:_NDPOptionIdentifier_index_0[i+1]] + case i == 25: + return _NDPOptionIdentifier_name_1 + default: + return "NDPOptionIdentifier(" + strconv.FormatInt(int64(i), 10) + ")" + } +} diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index 7f66c6c09..8140c6dd4 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -711,7 +711,8 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { continue } - ndp.nic.stack.ndpDisp.OnRecursiveDNSServerOption(ndp.nic.ID(), opt.Addresses(), opt.Lifetime()) + addrs, _ := opt.Addresses() + ndp.nic.stack.ndpDisp.OnRecursiveDNSServerOption(ndp.nic.ID(), addrs, opt.Lifetime()) case header.NDPPrefixInformation: prefix := opt.Subnet() -- cgit v1.2.3 From 486759a37d61b770019a81af00e0e733c655b3a8 Mon Sep 17 00:00:00 2001 From: Ghanan Gowripalan Date: Fri, 17 Apr 2020 13:54:47 -0700 Subject: Support NDP DNS Search List option Inform the netstack integrator when the netstack receives an NDP Router Advertisement message with the NDP DNS Search List option with at least one domain name. The stack will not maintain any state related to the search list - the integrator is expected to maintain any required state and invalidate domain names after their lifetime expires, or refresh the lifetime when a new one is received for a known domain name. Test: - header_test.TestNDPDNSSearchListOption - header_test.TestNDPDNSSearchListOptionSerialize - header_test.TestNDPSearchListOptionDomainNameLabelInvalidSymbols - header_test.TestNDPOptionsIterCheck - stack_test.TestNDPDNSSearchListDispatch PiperOrigin-RevId: 307109375 --- pkg/tcpip/header/ndp_options.go | 213 +++++++++++++++ pkg/tcpip/header/ndp_test.go | 574 ++++++++++++++++++++++++++++++++++++++++ pkg/tcpip/stack/ndp.go | 18 ++ pkg/tcpip/stack/ndp_test.go | 125 +++++++++ 4 files changed, 930 insertions(+) (limited to 'pkg/tcpip/header/ndp_options.go') diff --git a/pkg/tcpip/header/ndp_options.go b/pkg/tcpip/header/ndp_options.go index 444e90820..5d3975c56 100644 --- a/pkg/tcpip/header/ndp_options.go +++ b/pkg/tcpip/header/ndp_options.go @@ -45,6 +45,10 @@ const ( // NDPRecursiveDNSServerOptionType is the type of the Recursive DNS // Server option, as per RFC 8106 section 5.1. NDPRecursiveDNSServerOptionType NDPOptionIdentifier = 25 + + // NDPDNSSearchListOptionType is the type of the DNS Search List option, + // as per RFC 8106 section 5.2. + NDPDNSSearchListOptionType = 31 ) const ( @@ -115,6 +119,27 @@ const ( // RFC 8106 section 5.3.1. minNDPRecursiveDNSServerBodySize = 22 + // ndpDNSSearchListLifetimeOffset is the start of the 4-byte + // Lifetime field within an NDPDNSSearchList. + ndpDNSSearchListLifetimeOffset = 2 + + // ndpDNSSearchListDomainNamesOffset is the start of the DNS search list + // domain names within an NDPDNSSearchList. + ndpDNSSearchListDomainNamesOffset = 6 + + // minNDPDNSSearchListBodySize is the minimum NDP DNS Search List option's + // body size when it contains at least one domain name, as per RFC 8106 + // section 5.3.1. + minNDPDNSSearchListBodySize = 14 + + // maxDomainNameLabelLength is the maximum length of a domain name + // label, as per RFC 1035 section 3.1. + maxDomainNameLabelLength = 63 + + // maxDomainNameLength is the maximum length of a domain name, including + // label AND label length octet, as per RFC 1035 section 3.1. + maxDomainNameLength = 255 + // lengthByteUnits is the multiplier factor for the Length field of an // NDP option. That is, the length field for NDP options is in units of // 8 octets, as per RFC 4861 section 4.6. @@ -224,6 +249,14 @@ func (i *NDPOptionIterator) Next() (NDPOption, bool, error) { return opt, false, nil + case NDPDNSSearchListOptionType: + opt := NDPDNSSearchList(body) + if err := opt.checkDomainNames(); err != nil { + return nil, true, err + } + + return opt, false, nil + default: // We do not yet recognize the option, just skip for // now. This is okay because RFC 4861 allows us to @@ -684,3 +717,183 @@ func (o NDPRecursiveDNSServer) iterAddresses(fn func(tcpip.Address)) error { return nil } + +// NDPDNSSearchList is the NDP DNS Search List option, as defined by +// RFC 8106 section 5.2. +type NDPDNSSearchList []byte + +// Type implements NDPOption.Type. +func (o NDPDNSSearchList) Type() NDPOptionIdentifier { + return NDPDNSSearchListOptionType +} + +// Length implements NDPOption.Length. +func (o NDPDNSSearchList) Length() int { + return len(o) +} + +// serializeInto implements NDPOption.serializeInto. +func (o NDPDNSSearchList) serializeInto(b []byte) int { + used := copy(b, o) + + // Zero out the reserved bytes that are before the Lifetime field. + for i := 0; i < ndpDNSSearchListLifetimeOffset; i++ { + b[i] = 0 + } + + return used +} + +// String implements fmt.Stringer.String. +func (o NDPDNSSearchList) String() string { + lt := o.Lifetime() + domainNames, err := o.DomainNames() + if err != nil { + return fmt.Sprintf("%T([] valid for %s; err = %s)", o, lt, err) + } + return fmt.Sprintf("%T(%s valid for %s)", o, domainNames, lt) +} + +// Lifetime returns the length of time that the DNS search list of domain names +// in this option may be used for name resolution. +// +// Note, a value of 0 implies the domain names should no longer be used, +// and a value of infinity/forever is represented by NDPInfiniteLifetime. +func (o NDPDNSSearchList) Lifetime() time.Duration { + // The field is the time in seconds, as per RFC 8106 section 5.1. + return time.Second * time.Duration(binary.BigEndian.Uint32(o[ndpDNSSearchListLifetimeOffset:])) +} + +// DomainNames returns a DNS search list of domain names. +// +// DomainNames will parse the backing buffer as outlined by RFC 1035 section +// 3.1 and return a list of strings, with all domain names in lower case. +func (o NDPDNSSearchList) DomainNames() ([]string, error) { + var domainNames []string + return domainNames, o.iterDomainNames(func(domainName string) { domainNames = append(domainNames, domainName) }) +} + +// checkDomainNames iterates over the domain names in an NDP DNS Search List +// option and returns any error it encounters. +func (o NDPDNSSearchList) checkDomainNames() error { + return o.iterDomainNames(nil) +} + +// iterDomainNames iterates over the domain names in an NDP DNS Search List +// option and calls a function with each valid domain name. +func (o NDPDNSSearchList) iterDomainNames(fn func(string)) error { + if l := len(o); l < minNDPDNSSearchListBodySize { + return fmt.Errorf("got %d bytes for NDP DNS Search List option's body, expected at least %d bytes: %w", l, minNDPDNSSearchListBodySize, io.ErrUnexpectedEOF) + } + + var searchList bytes.Reader + searchList.Reset(o[ndpDNSSearchListDomainNamesOffset:]) + + var scratch [maxDomainNameLength]byte + domainName := bytes.NewBuffer(scratch[:]) + + // Parse the domain names, as per RFC 1035 section 3.1. + for searchList.Len() != 0 { + domainName.Reset() + + // Parse a label within a domain name, as per RFC 1035 section 3.1. + for { + // The first byte is the label length. + labelLenByte, err := searchList.ReadByte() + if err != nil { + if err != io.EOF { + // ReadByte should only ever return nil or io.EOF. + panic(fmt.Sprintf("unexpected error when reading a label's length: %s", err)) + } + + // We use io.ErrUnexpectedEOF as exhausting the buffer is unexpected + // once we start parsing a domain name; we expect the buffer to contain + // enough bytes for the whole domain name. + return fmt.Errorf("unexpected exhausted buffer while parsing a new label for a domain from NDP Search List option: %w", io.ErrUnexpectedEOF) + } + labelLen := int(labelLenByte) + + // A zero-length label implies the end of a domain name. + if labelLen == 0 { + // If the domain name is empty or we have no callback function, do + // nothing further with the current domain name. + if domainName.Len() == 0 || fn == nil { + break + } + + // Ignore the trailing period in the parsed domain name. + domainName.Truncate(domainName.Len() - 1) + fn(domainName.String()) + break + } + + // The label's length must not exceed the maximum length for a label. + if labelLen > maxDomainNameLabelLength { + return fmt.Errorf("label length of %d bytes is greater than the max label length of %d bytes for an NDP Search List option: %w", labelLen, maxDomainNameLabelLength, ErrNDPOptMalformedBody) + } + + // The label (and trailing period) must not make the domain name too long. + if labelLen+1 > domainName.Cap()-domainName.Len() { + return fmt.Errorf("label would make an NDP Search List option's domain name longer than the max domain name length of %d bytes: %w", maxDomainNameLength, ErrNDPOptMalformedBody) + } + + // Copy the label and add a trailing period. + for i := 0; i < labelLen; i++ { + b, err := searchList.ReadByte() + if err != nil { + if err != io.EOF { + panic(fmt.Sprintf("unexpected error when reading domain name's label: %s", err)) + } + + return fmt.Errorf("read %d out of %d bytes for a domain name's label from NDP Search List option: %w", i, labelLen, io.ErrUnexpectedEOF) + } + + // As per RFC 1035 section 2.3.1: + // 1) the label must only contain ASCII include letters, digits and + // hyphens + // 2) the first character in a label must be a letter + // 3) the last letter in a label must be a letter or digit + + if !isLetter(b) { + if i == 0 { + return fmt.Errorf("first character of a domain name's label in an NDP Search List option must be a letter, got character code = %d: %w", b, ErrNDPOptMalformedBody) + } + + if b == '-' { + if i == labelLen-1 { + return fmt.Errorf("last character of a domain name's label in an NDP Search List option must not be a hyphen (-): %w", ErrNDPOptMalformedBody) + } + } else if !isDigit(b) { + return fmt.Errorf("domain name's label in an NDP Search List option may only contain letters, digits and hyphens, got character code = %d: %w", b, ErrNDPOptMalformedBody) + } + } + + // If b is an upper case character, make it lower case. + if isUpperLetter(b) { + b = b - 'A' + 'a' + } + + if err := domainName.WriteByte(b); err != nil { + panic(fmt.Sprintf("unexpected error writing label to domain name buffer: %s", err)) + } + } + if err := domainName.WriteByte('.'); err != nil { + panic(fmt.Sprintf("unexpected error writing trailing period to domain name buffer: %s", err)) + } + } + } + + return nil +} + +func isLetter(b byte) bool { + return b >= 'a' && b <= 'z' || isUpperLetter(b) +} + +func isUpperLetter(b byte) bool { + return b >= 'A' && b <= 'Z' +} + +func isDigit(b byte) bool { + return b >= '0' && b <= '9' +} diff --git a/pkg/tcpip/header/ndp_test.go b/pkg/tcpip/header/ndp_test.go index 2341329c4..dc4591253 100644 --- a/pkg/tcpip/header/ndp_test.go +++ b/pkg/tcpip/header/ndp_test.go @@ -17,7 +17,9 @@ package header import ( "bytes" "errors" + "fmt" "io" + "regexp" "testing" "time" @@ -667,6 +669,477 @@ func TestNDPRecursiveDNSServerOption(t *testing.T) { } } +// TestNDPDNSSearchListOption tests the getters of NDPDNSSearchList. +func TestNDPDNSSearchListOption(t *testing.T) { + tests := []struct { + name string + buf []byte + lifetime time.Duration + domainNames []string + err error + }{ + { + name: "Valid1Label", + buf: []byte{ + 0, 0, + 0, 0, 0, 1, + 3, 'a', 'b', 'c', + 0, + 0, 0, 0, + }, + lifetime: time.Second, + domainNames: []string{ + "abc", + }, + err: nil, + }, + { + name: "Valid2Label", + buf: []byte{ + 0, 0, + 0, 0, 0, 5, + 3, 'a', 'b', 'c', + 4, 'a', 'b', 'c', 'd', + 0, + 0, 0, 0, 0, 0, 0, + }, + lifetime: 5 * time.Second, + domainNames: []string{ + "abc.abcd", + }, + err: nil, + }, + { + name: "Valid3Label", + buf: []byte{ + 0, 0, + 1, 0, 0, 0, + 3, 'a', 'b', 'c', + 4, 'a', 'b', 'c', 'd', + 1, 'e', + 0, + 0, 0, 0, 0, + }, + lifetime: 16777216 * time.Second, + domainNames: []string{ + "abc.abcd.e", + }, + err: nil, + }, + { + name: "Valid2Domains", + buf: []byte{ + 0, 0, + 1, 2, 3, 4, + 3, 'a', 'b', 'c', + 0, + 2, 'd', 'e', + 3, 'x', 'y', 'z', + 0, + 0, 0, 0, + }, + lifetime: 16909060 * time.Second, + domainNames: []string{ + "abc", + "de.xyz", + }, + err: nil, + }, + { + name: "Valid3DomainsMixedCase", + buf: []byte{ + 0, 0, + 0, 0, 0, 0, + 3, 'a', 'B', 'c', + 0, + 2, 'd', 'E', + 3, 'X', 'y', 'z', + 0, + 1, 'J', + 0, + }, + lifetime: 0, + domainNames: []string{ + "abc", + "de.xyz", + "j", + }, + err: nil, + }, + { + name: "ValidDomainAfterNULL", + buf: []byte{ + 0, 0, + 0, 0, 0, 0, + 3, 'a', 'B', 'c', + 0, 0, 0, 0, + 2, 'd', 'E', + 3, 'X', 'y', 'z', + 0, + }, + lifetime: 0, + domainNames: []string{ + "abc", + "de.xyz", + }, + err: nil, + }, + { + name: "Valid0Domains", + buf: []byte{ + 0, 0, + 0, 0, 0, 0, + 0, + 0, 0, 0, 0, 0, 0, 0, + }, + lifetime: 0, + domainNames: nil, + err: nil, + }, + { + name: "NoTrailingNull", + buf: []byte{ + 0, 0, + 0, 0, 0, 0, + 7, 'a', 'b', 'c', 'd', 'e', 'f', 'g', + }, + lifetime: 0, + domainNames: nil, + err: io.ErrUnexpectedEOF, + }, + { + name: "IncorrectLength", + buf: []byte{ + 0, 0, + 0, 0, 0, 0, + 8, 'a', 'b', 'c', 'd', 'e', 'f', 'g', + }, + lifetime: 0, + domainNames: nil, + err: io.ErrUnexpectedEOF, + }, + { + name: "IncorrectLengthWithNULL", + buf: []byte{ + 0, 0, + 0, 0, 0, 0, + 7, 'a', 'b', 'c', 'd', 'e', 'f', + 0, + }, + lifetime: 0, + domainNames: nil, + err: ErrNDPOptMalformedBody, + }, + { + name: "LabelOfLength63", + buf: []byte{ + 0, 0, + 0, 0, 0, 0, + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 0, + }, + lifetime: 0, + domainNames: []string{ + "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijk", + }, + err: nil, + }, + { + name: "LabelOfLength64", + buf: []byte{ + 0, 0, + 0, 0, 0, 0, + 64, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', + 0, + }, + lifetime: 0, + domainNames: nil, + err: ErrNDPOptMalformedBody, + }, + { + name: "DomainNameOfLength255", + buf: []byte{ + 0, 0, + 0, 0, 0, 0, + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 62, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', + 0, + }, + lifetime: 0, + domainNames: []string{ + "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijk.abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijk.abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijk.abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghij", + }, + err: nil, + }, + { + name: "DomainNameOfLength256", + buf: []byte{ + 0, 0, + 0, 0, 0, 0, + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 0, + }, + lifetime: 0, + domainNames: nil, + err: ErrNDPOptMalformedBody, + }, + { + name: "StartingDigitForLabel", + buf: []byte{ + 0, 0, + 0, 0, 0, 1, + 3, '9', 'b', 'c', + 0, + 0, 0, 0, + }, + lifetime: time.Second, + domainNames: nil, + err: ErrNDPOptMalformedBody, + }, + { + name: "StartingHyphenForLabel", + buf: []byte{ + 0, 0, + 0, 0, 0, 1, + 3, '-', 'b', 'c', + 0, + 0, 0, 0, + }, + lifetime: time.Second, + domainNames: nil, + err: ErrNDPOptMalformedBody, + }, + { + name: "EndingHyphenForLabel", + buf: []byte{ + 0, 0, + 0, 0, 0, 1, + 3, 'a', 'b', '-', + 0, + 0, 0, 0, + }, + lifetime: time.Second, + domainNames: nil, + err: ErrNDPOptMalformedBody, + }, + { + name: "EndingDigitForLabel", + buf: []byte{ + 0, 0, + 0, 0, 0, 1, + 3, 'a', 'b', '9', + 0, + 0, 0, 0, + }, + lifetime: time.Second, + domainNames: []string{ + "ab9", + }, + err: nil, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + opt := NDPDNSSearchList(test.buf) + + if got := opt.Lifetime(); got != test.lifetime { + t.Errorf("got Lifetime = %d, want = %d", got, test.lifetime) + } + domainNames, err := opt.DomainNames() + if !errors.Is(err, test.err) { + t.Errorf("opt.DomainNames() = %s", err) + } + if diff := cmp.Diff(domainNames, test.domainNames); diff != "" { + t.Errorf("mismatched domain names (-want +got):\n%s", diff) + } + }) + } +} + +func TestNDPSearchListOptionDomainNameLabelInvalidSymbols(t *testing.T) { + for r := rune(0); r <= 255; r++ { + t.Run(fmt.Sprintf("RuneVal=%d", r), func(t *testing.T) { + buf := []byte{ + 0, 0, + 0, 0, 0, 0, + 3, 'a', 0 /* will be replaced */, 'c', + 0, + 0, 0, 0, + } + buf[8] = uint8(r) + opt := NDPDNSSearchList(buf) + + // As per RFC 1035 section 2.3.1, the label must only include ASCII + // letters, digits and hyphens (a-z, A-Z, 0-9, -). + var expectedErr error + re := regexp.MustCompile(`[a-zA-Z0-9-]`) + if !re.Match([]byte{byte(r)}) { + expectedErr = ErrNDPOptMalformedBody + } + + if domainNames, err := opt.DomainNames(); !errors.Is(err, expectedErr) { + t.Errorf("got opt.DomainNames() = (%s, %v), want = (_, %v)", domainNames, err, ErrNDPOptMalformedBody) + } + }) + } +} + +func TestNDPDNSSearchListOptionSerialize(t *testing.T) { + b := []byte{ + 9, 8, + 1, 0, 0, 0, + 3, 'a', 'b', 'c', + 4, 'a', 'b', 'c', 'd', + 1, 'e', + 0, + } + targetBuf := []byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1} + expected := []byte{ + 31, 3, 0, 0, + 1, 0, 0, 0, + 3, 'a', 'b', 'c', + 4, 'a', 'b', 'c', 'd', + 1, 'e', + 0, + 0, 0, 0, 0, + } + opts := NDPOptions(targetBuf) + serializer := NDPOptionsSerializer{ + NDPDNSSearchList(b), + } + if got, want := opts.Serialize(serializer), len(expected); got != want { + t.Errorf("got Serialize = %d, want = %d", got, want) + } + if !bytes.Equal(targetBuf, expected) { + t.Fatalf("got targetBuf = %x, want = %x", targetBuf, expected) + } + + it, err := opts.Iter(true) + if err != nil { + t.Fatalf("got Iter = (_, %s), want = (_, nil)", err) + } + + next, done, err := it.Next() + if err != nil { + t.Fatalf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if done { + t.Fatal("got Next = (_, true, _), want = (_, false, _)") + } + if got := next.Type(); got != NDPDNSSearchListOptionType { + t.Errorf("got Type = %d, want = %d", got, NDPDNSSearchListOptionType) + } + + opt, ok := next.(NDPDNSSearchList) + if !ok { + t.Fatalf("next (type = %T) cannot be casted to an NDPDNSSearchList", next) + } + if got := opt.Type(); got != 31 { + t.Errorf("got Type = %d, want = 31", got) + } + if got := opt.Length(); got != 22 { + t.Errorf("got Length = %d, want = 22", got) + } + if got, want := opt.Lifetime(), 16777216*time.Second; got != want { + t.Errorf("got Lifetime = %s, want = %s", got, want) + } + domainNames, err := opt.DomainNames() + if err != nil { + t.Errorf("opt.DomainNames() = %s", err) + } + if diff := cmp.Diff(domainNames, []string{"abc.abcd.e"}); diff != "" { + t.Errorf("domain names mismatch (-want +got):\n%s", diff) + } + + // Iterator should not return anything else. + next, done, err = it.Next() + if err != nil { + t.Errorf("got Next = (_, _, %s), want = (_, _, nil)", err) + } + if !done { + t.Error("got Next = (_, false, _), want = (_, true, _)") + } + if next != nil { + t.Errorf("got Next = (%x, _, _), want = (nil, _, _)", next) + } +} + // TestNDPOptionsIterCheck tests that Iter will return false if the NDPOptions // the iterator was returned for is malformed. func TestNDPOptionsIterCheck(t *testing.T) { @@ -832,6 +1305,107 @@ func TestNDPOptionsIterCheck(t *testing.T) { }, expectedErr: ErrNDPOptMalformedBody, }, + { + name: "DNSSearchListLargeCompliantRFC1035", + buf: []byte{ + 31, 33, 0, 0, + 0, 0, 0, 0, + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 62, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', + 0, + }, + expectedErr: nil, + }, + { + name: "DNSSearchListNonCompliantRFC1035", + buf: []byte{ + 31, 33, 0, 0, + 0, 0, 0, 0, + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 63, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', + 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', + 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', + 'i', 'j', 'k', + 0, + 0, 0, 0, 0, 0, 0, 0, 0, + }, + expectedErr: ErrNDPOptMalformedBody, + }, + { + name: "DNSSearchListValidSmall", + buf: []byte{ + 31, 2, 0, 0, + 0, 0, 0, 0, + 6, 'a', 'b', 'c', 'd', 'e', 'f', + 0, + }, + expectedErr: nil, + }, + { + name: "DNSSearchListTooSmall", + buf: []byte{ + 31, 1, 0, 0, + 0, 0, 0, + }, + expectedErr: io.ErrUnexpectedEOF, + }, } for _, test := range tests { diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index 8140c6dd4..193a9dfde 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -241,6 +241,16 @@ type NDPDispatcher interface { // call functions on the stack itself. OnRecursiveDNSServerOption(nicID tcpip.NICID, addrs []tcpip.Address, lifetime time.Duration) + // OnDNSSearchListOption will be called when an NDP option with a DNS + // search list has been received. + // + // It is up to the caller to use the domain names in the search list + // for only their valid lifetime. OnDNSSearchListOption may be called + // with new or already known domain names. If called with known domain + // names, their valid lifetimes must be refreshed to lifetime (it may + // be increased, decreased or completely invalidated when lifetime = 0. + OnDNSSearchListOption(nicID tcpip.NICID, domainNames []string, lifetime time.Duration) + // OnDHCPv6Configuration will be called with an updated configuration that is // available via DHCPv6 for a specified NIC. // @@ -714,6 +724,14 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { addrs, _ := opt.Addresses() ndp.nic.stack.ndpDisp.OnRecursiveDNSServerOption(ndp.nic.ID(), addrs, opt.Lifetime()) + case header.NDPDNSSearchList: + if ndp.nic.stack.ndpDisp == nil { + continue + } + + domainNames, _ := opt.DomainNames() + ndp.nic.stack.ndpDisp.OnDNSSearchListOption(ndp.nic.ID(), domainNames, opt.Lifetime()) + case header.NDPPrefixInformation: prefix := opt.Subnet() diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go index 6562a2d22..6dd460984 100644 --- a/pkg/tcpip/stack/ndp_test.go +++ b/pkg/tcpip/stack/ndp_test.go @@ -133,6 +133,12 @@ type ndpRDNSSEvent struct { rdnss ndpRDNSS } +type ndpDNSSLEvent struct { + nicID tcpip.NICID + domainNames []string + lifetime time.Duration +} + type ndpDHCPv6Event struct { nicID tcpip.NICID configuration stack.DHCPv6ConfigurationFromNDPRA @@ -150,6 +156,8 @@ type ndpDispatcher struct { rememberPrefix bool autoGenAddrC chan ndpAutoGenAddrEvent rdnssC chan ndpRDNSSEvent + dnsslC chan ndpDNSSLEvent + routeTable []tcpip.Route dhcpv6ConfigurationC chan ndpDHCPv6Event } @@ -257,6 +265,17 @@ func (n *ndpDispatcher) OnRecursiveDNSServerOption(nicID tcpip.NICID, addrs []tc } } +// Implements stack.NDPDispatcher.OnDNSSearchListOption. +func (n *ndpDispatcher) OnDNSSearchListOption(nicID tcpip.NICID, domainNames []string, lifetime time.Duration) { + if n.dnsslC != nil { + n.dnsslC <- ndpDNSSLEvent{ + nicID, + domainNames, + lifetime, + } + } +} + // Implements stack.NDPDispatcher.OnDHCPv6Configuration. func (n *ndpDispatcher) OnDHCPv6Configuration(nicID tcpip.NICID, configuration stack.DHCPv6ConfigurationFromNDPRA) { if c := n.dhcpv6ConfigurationC; c != nil { @@ -3386,6 +3405,112 @@ func TestNDPRecursiveDNSServerDispatch(t *testing.T) { } } +// TestNDPDNSSearchListDispatch tests that the integrator is informed when an +// NDP DNS Search List option is received with at least one domain name in the +// search list. +func TestNDPDNSSearchListDispatch(t *testing.T) { + const nicID = 1 + + ndpDisp := ndpDispatcher{ + dnsslC: make(chan ndpDNSSLEvent, 3), + } + e := channel.New(0, 1280, linkAddr1) + s := stack.New(stack.Options{ + NetworkProtocols: []stack.NetworkProtocol{ipv6.NewProtocol()}, + NDPConfigs: stack.NDPConfigurations{ + HandleRAs: true, + }, + NDPDisp: &ndpDisp, + }) + if err := s.CreateNIC(nicID, e); err != nil { + t.Fatalf("CreateNIC(%d, _) = %s", nicID, err) + } + + optSer := header.NDPOptionsSerializer{ + header.NDPDNSSearchList([]byte{ + 0, 0, + 0, 0, 0, 0, + 2, 'h', 'i', + 0, + }), + header.NDPDNSSearchList([]byte{ + 0, 0, + 0, 0, 0, 1, + 1, 'i', + 0, + 2, 'a', 'm', + 2, 'm', 'e', + 0, + }), + header.NDPDNSSearchList([]byte{ + 0, 0, + 0, 0, 1, 0, + 3, 'x', 'y', 'z', + 0, + 5, 'h', 'e', 'l', 'l', 'o', + 5, 'w', 'o', 'r', 'l', 'd', + 0, + 4, 't', 'h', 'i', 's', + 2, 'i', 's', + 1, 'a', + 4, 't', 'e', 's', 't', + 0, + }), + } + expected := []struct { + domainNames []string + lifetime time.Duration + }{ + { + domainNames: []string{ + "hi", + }, + lifetime: 0, + }, + { + domainNames: []string{ + "i", + "am.me", + }, + lifetime: time.Second, + }, + { + domainNames: []string{ + "xyz", + "hello.world", + "this.is.a.test", + }, + lifetime: 256 * time.Second, + }, + } + + e.InjectInbound(header.IPv6ProtocolNumber, raBufWithOpts(llAddr1, 0, optSer)) + + for i, expected := range expected { + select { + case dnssl := <-ndpDisp.dnsslC: + if dnssl.nicID != nicID { + t.Errorf("got %d-th dnssl nicID = %d, want = %d", i, dnssl.nicID, nicID) + } + if diff := cmp.Diff(dnssl.domainNames, expected.domainNames); diff != "" { + t.Errorf("%d-th dnssl domain names mismatch (-want +got):\n%s", i, diff) + } + if dnssl.lifetime != expected.lifetime { + t.Errorf("got %d-th dnssl lifetime = %s, want = %s", i, dnssl.lifetime, expected.lifetime) + } + default: + t.Fatal("expected a DNSSL event") + } + } + + // Should have no more DNSSL options. + select { + case <-ndpDisp.dnsslC: + t.Fatal("unexpectedly got a DNSSL event") + default: + } +} + // TestCleanupNDPState tests that all discovered routers and prefixes, and // auto-generated addresses are invalidated when a NIC becomes a router. func TestCleanupNDPState(t *testing.T) { -- cgit v1.2.3