diff options
author | Kevin Krakauer <krakauer@google.com> | 2020-01-21 13:16:25 -0800 |
---|---|---|
committer | Kevin Krakauer <krakauer@google.com> | 2020-01-21 13:16:25 -0800 |
commit | 62357a0afb5f4128a11dc9a1dfadd2957ec39e2d (patch) | |
tree | 2f93dc1bb5680434f3bcd69df60d45af89777a94 /pkg/tcpip/stack/nic.go | |
parent | bd292894097ffdf316bc78d81aebd0a2988124f3 (diff) | |
parent | 2ba6198851dc1e293295d7cadf8c0ae456b68beb (diff) |
Merge branch 'master' into iptables-write-filter-proto
Diffstat (limited to 'pkg/tcpip/stack/nic.go')
-rw-r--r-- | pkg/tcpip/stack/nic.go | 250 |
1 files changed, 194 insertions, 56 deletions
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index d50693634..de88c0bfa 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -15,6 +15,8 @@ package stack import ( + "log" + "sort" "strings" "sync/atomic" @@ -175,49 +177,72 @@ func (n *NIC) enable() *tcpip.Error { } // Do not auto-generate an IPv6 link-local address for loopback devices. - if !n.stack.autoGenIPv6LinkLocal || n.isLoopback() { - return nil - } + if n.stack.autoGenIPv6LinkLocal && !n.isLoopback() { + var addr tcpip.Address + if oIID := n.stack.opaqueIIDOpts; oIID.NICNameFromID != nil { + addr = header.LinkLocalAddrWithOpaqueIID(oIID.NICNameFromID(n.ID(), n.name), 0, oIID.SecretKey) + } else { + l2addr := n.linkEP.LinkAddress() - var addr tcpip.Address - if oIID := n.stack.opaqueIIDOpts; oIID.NICNameFromID != nil { - addr = header.LinkLocalAddrWithOpaqueIID(oIID.NICNameFromID(n.ID(), n.name), 0, oIID.SecretKey) - } else { - l2addr := n.linkEP.LinkAddress() + // Only attempt to generate the link-local address if we have a valid MAC + // address. + // + // TODO(b/141011931): Validate a LinkEndpoint's link address (provided by + // LinkEndpoint.LinkAddress) before reaching this point. + if !header.IsValidUnicastEthernetAddress(l2addr) { + return nil + } - // Only attempt to generate the link-local address if we have a valid MAC - // address. - // - // TODO(b/141011931): Validate a LinkEndpoint's link address (provided by - // LinkEndpoint.LinkAddress) before reaching this point. - if !header.IsValidUnicastEthernetAddress(l2addr) { - return nil + addr = header.LinkLocalAddr(l2addr) } - addr = header.LinkLocalAddr(l2addr) + if _, err := n.addAddressLocked(tcpip.ProtocolAddress{ + Protocol: header.IPv6ProtocolNumber, + AddressWithPrefix: tcpip.AddressWithPrefix{ + Address: addr, + PrefixLen: header.IPv6LinkLocalPrefix.PrefixLen, + }, + }, CanBePrimaryEndpoint, permanent, static, false /* deprecated */); err != nil { + return err + } } - _, err := n.addPermanentAddressLocked(tcpip.ProtocolAddress{ - Protocol: header.IPv6ProtocolNumber, - AddressWithPrefix: tcpip.AddressWithPrefix{ - Address: addr, - PrefixLen: header.IPv6LinkLocalPrefix.PrefixLen, - }, - }, CanBePrimaryEndpoint) + // If we are operating as a router, then do not solicit routers since we + // won't process the RAs anyways. + // + // Routers do not process Router Advertisements (RA) the same way a host + // does. That is, routers do not learn from RAs (e.g. on-link prefixes + // and default routers). Therefore, soliciting RAs from other routers on + // a link is unnecessary for routers. + if !n.stack.forwarding { + n.ndp.startSolicitingRouters() + } - return err + return nil } // becomeIPv6Router transitions n into an IPv6 router. // // When transitioning into an IPv6 router, host-only state (NDP discovered // routers, discovered on-link prefixes, and auto-generated addresses) will -// be cleaned up/invalidated. +// be cleaned up/invalidated and NDP router solicitations will be stopped. func (n *NIC) becomeIPv6Router() { n.mu.Lock() defer n.mu.Unlock() n.ndp.cleanupHostOnlyState() + n.ndp.stopSolicitingRouters() +} + +// becomeIPv6Host transitions n into an IPv6 host. +// +// When transitioning into an IPv6 host, NDP router solicitations will be +// started. +func (n *NIC) becomeIPv6Host() { + n.mu.Lock() + defer n.mu.Unlock() + + n.ndp.startSolicitingRouters() } // attachLinkEndpoint attaches the NIC to the endpoint, which will enable it @@ -251,13 +276,17 @@ func (n *NIC) setSpoofing(enable bool) { n.mu.Unlock() } -// primaryEndpoint returns the primary endpoint of n for the given network -// protocol. -// // primaryEndpoint will return the first non-deprecated endpoint if such an -// endpoint exists. If no non-deprecated endpoint exists, the first deprecated -// endpoint will be returned. -func (n *NIC) primaryEndpoint(protocol tcpip.NetworkProtocolNumber) *referencedNetworkEndpoint { +// endpoint exists for the given protocol and remoteAddr. If no non-deprecated +// endpoint exists, the first deprecated endpoint will be returned. +// +// If an IPv6 primary endpoint is requested, Source Address Selection (as +// defined by RFC 6724 section 5) will be performed. +func (n *NIC) primaryEndpoint(protocol tcpip.NetworkProtocolNumber, remoteAddr tcpip.Address) *referencedNetworkEndpoint { + if protocol == header.IPv6ProtocolNumber && remoteAddr != "" { + return n.primaryIPv6Endpoint(remoteAddr) + } + n.mu.RLock() defer n.mu.RUnlock() @@ -296,6 +325,103 @@ func (n *NIC) primaryEndpoint(protocol tcpip.NetworkProtocolNumber) *referencedN return deprecatedEndpoint } +// ipv6AddrCandidate is an IPv6 candidate for Source Address Selection (RFC +// 6724 section 5). +type ipv6AddrCandidate struct { + ref *referencedNetworkEndpoint + scope header.IPv6AddressScope +} + +// primaryIPv6Endpoint returns an IPv6 endpoint following Source Address +// Selection (RFC 6724 section 5). +// +// Note, only rules 1-3 are followed. +// +// remoteAddr must be a valid IPv6 address. +func (n *NIC) primaryIPv6Endpoint(remoteAddr tcpip.Address) *referencedNetworkEndpoint { + n.mu.RLock() + defer n.mu.RUnlock() + + primaryAddrs := n.primary[header.IPv6ProtocolNumber] + + if len(primaryAddrs) == 0 { + return nil + } + + // Create a candidate set of available addresses we can potentially use as a + // source address. + cs := make([]ipv6AddrCandidate, 0, len(primaryAddrs)) + for _, r := range primaryAddrs { + // If r is not valid for outgoing connections, it is not a valid endpoint. + if !r.isValidForOutgoing() { + continue + } + + addr := r.ep.ID().LocalAddress + scope, err := header.ScopeForIPv6Address(addr) + if err != nil { + // Should never happen as we got r from the primary IPv6 endpoint list and + // ScopeForIPv6Address only returns an error if addr is not an IPv6 + // address. + log.Fatalf("header.ScopeForIPv6Address(%s): %s", addr, err) + } + + cs = append(cs, ipv6AddrCandidate{ + ref: r, + scope: scope, + }) + } + + remoteScope, err := header.ScopeForIPv6Address(remoteAddr) + if err != nil { + // primaryIPv6Endpoint should never be called with an invalid IPv6 address. + log.Fatalf("header.ScopeForIPv6Address(%s): %s", remoteAddr, err) + } + + // Sort the addresses as per RFC 6724 section 5 rules 1-3. + // + // TODO(b/146021396): Implement rules 4-8 of RFC 6724 section 5. + sort.Slice(cs, func(i, j int) bool { + sa := cs[i] + sb := cs[j] + + // Prefer same address as per RFC 6724 section 5 rule 1. + if sa.ref.ep.ID().LocalAddress == remoteAddr { + return true + } + if sb.ref.ep.ID().LocalAddress == remoteAddr { + return false + } + + // Prefer appropriate scope as per RFC 6724 section 5 rule 2. + if sa.scope < sb.scope { + return sa.scope >= remoteScope + } else if sb.scope < sa.scope { + return sb.scope < remoteScope + } + + // Avoid deprecated addresses as per RFC 6724 section 5 rule 3. + if saDep, sbDep := sa.ref.deprecated, sb.ref.deprecated; saDep != sbDep { + // If sa is not deprecated, it is preferred over sb. + return sbDep + } + + // sa and sb are equal, return the endpoint that is closest to the front of + // the primary endpoint list. + return i < j + }) + + // Return the most preferred address that can have its reference count + // incremented. + for _, c := range cs { + if r := c.ref; r.tryIncRef() { + return r + } + } + + return nil +} + // hasPermanentAddrLocked returns true if n has a permanent (including currently // tentative) address, addr. func (n *NIC) hasPermanentAddrLocked(addr tcpip.Address) bool { @@ -407,18 +533,34 @@ func (n *NIC) getRefOrCreateTemp(protocol tcpip.NetworkProtocolNumber, address t return ref } -func (n *NIC) addPermanentAddressLocked(protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior) (*referencedNetworkEndpoint, *tcpip.Error) { - id := NetworkEndpointID{protocolAddress.AddressWithPrefix.Address} +// addAddressLocked adds a new protocolAddress to n. +// +// If n already has the address in a non-permanent state, and the kind given is +// permanent, that address will be promoted in place and its properties set to +// the properties provided. Otherwise, it returns tcpip.ErrDuplicateAddress. +func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior, kind networkEndpointKind, configType networkEndpointConfigType, deprecated bool) (*referencedNetworkEndpoint, *tcpip.Error) { + // TODO(b/141022673): Validate IP addresses before adding them. + + // Sanity check. + id := NetworkEndpointID{LocalAddress: protocolAddress.AddressWithPrefix.Address} if ref, ok := n.endpoints[id]; ok { + // Endpoint already exists. + if kind != permanent { + return nil, tcpip.ErrDuplicateAddress + } switch ref.getKind() { case permanentTentative, permanent: // The NIC already have a permanent endpoint with that address. return nil, tcpip.ErrDuplicateAddress case permanentExpired, temporary: - // Promote the endpoint to become permanent and respect - // the new peb. + // Promote the endpoint to become permanent and respect the new peb, + // configType and deprecated status. if ref.tryIncRef() { + // TODO(b/147748385): Perform Duplicate Address Detection when promoting + // an IPv6 endpoint to permanent. ref.setKind(permanent) + ref.deprecated = deprecated + ref.configType = configType refs := n.primary[ref.protocol] for i, r := range refs { @@ -450,19 +592,6 @@ func (n *NIC) addPermanentAddressLocked(protocolAddress tcpip.ProtocolAddress, p } } - return n.addAddressLocked(protocolAddress, peb, permanent, static, false) -} - -func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior, kind networkEndpointKind, configType networkEndpointConfigType, deprecated bool) (*referencedNetworkEndpoint, *tcpip.Error) { - // TODO(b/141022673): Validate IP address before adding them. - - // Sanity check. - id := NetworkEndpointID{protocolAddress.AddressWithPrefix.Address} - if _, ok := n.endpoints[id]; ok { - // Endpoint already exists. - return nil, tcpip.ErrDuplicateAddress - } - netProto, ok := n.stack.networkProtocols[protocolAddress.Protocol] if !ok { return nil, tcpip.ErrUnknownProtocol @@ -527,7 +656,7 @@ func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb Primar func (n *NIC) AddAddress(protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior) *tcpip.Error { // Add the endpoint. n.mu.Lock() - _, err := n.addPermanentAddressLocked(protocolAddress, peb) + _, err := n.addAddressLocked(protocolAddress, peb, permanent, static, false /* deprecated */) n.mu.Unlock() return err @@ -660,7 +789,7 @@ func (n *NIC) RemoveAddressRange(subnet tcpip.Subnet) { n.mu.Unlock() } -// Subnets returns the Subnets associated with this NIC. +// AddressRanges returns the Subnets associated with this NIC. func (n *NIC) AddressRanges() []tcpip.Subnet { n.mu.RLock() defer n.mu.RUnlock() @@ -803,13 +932,13 @@ func (n *NIC) joinGroupLocked(protocol tcpip.NetworkProtocolNumber, addr tcpip.A if !ok { return tcpip.ErrUnknownProtocol } - if _, err := n.addPermanentAddressLocked(tcpip.ProtocolAddress{ + if _, err := n.addAddressLocked(tcpip.ProtocolAddress{ Protocol: protocol, AddressWithPrefix: tcpip.AddressWithPrefix{ Address: addr, PrefixLen: netProto.DefaultPrefixLen(), }, - }, NeverPrimaryEndpoint); err != nil { + }, NeverPrimaryEndpoint, permanent, static, false /* deprecated */); err != nil { return err } } @@ -855,7 +984,7 @@ func handlePacket(protocol tcpip.NetworkProtocolNumber, dst, src tcpip.Address, // DeliverNetworkPacket finds the appropriate network protocol endpoint and // hands the packet over for further processing. This function is called when -// the NIC receives a packet from the physical interface. +// the NIC receives a packet from the link endpoint. // Note that the ownership of the slice backing vv is retained by the caller. // This rule applies only to the slice itself, not to the items of the slice; // the ownership of the items is not retained by the caller. @@ -900,6 +1029,14 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.Link src, dst := netProto.ParseAddresses(pkt.Data.First()) + if n.stack.handleLocal && !n.isLoopback() && n.getRef(protocol, src) != nil { + // The source address is one of our own, so we never should have gotten a + // packet like this unless handleLocal is false. Loopback also calls this + // function even though the packets didn't come from the physical interface + // so don't drop those. + n.stack.stats.IP.InvalidSourceAddressesReceived.Increment() + return + } if ref := n.getRef(protocol, dst); ref != nil { handlePacket(protocol, dst, src, linkEP.LinkAddress(), remote, ref, pkt) return @@ -912,7 +1049,7 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.Link if n.stack.Forwarding() { r, err := n.stack.FindRoute(0, "", dst, protocol, false /* multicastLoop */) if err != nil { - n.stack.stats.IP.InvalidAddressesReceived.Increment() + n.stack.stats.IP.InvalidDestinationAddressesReceived.Increment() return } defer r.Release() @@ -950,7 +1087,7 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.Link // If a packet socket handled the packet, don't treat it as invalid. if len(packetEPs) == 0 { - n.stack.stats.IP.InvalidAddressesReceived.Increment() + n.stack.stats.IP.InvalidDestinationAddressesReceived.Increment() } } @@ -1187,7 +1324,8 @@ type referencedNetworkEndpoint struct { 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. + // This must never change except during endpoint creation and promotion to + // permanent. configType networkEndpointConfigType // deprecated indicates whether or not the endpoint should be considered |