diff options
Diffstat (limited to 'pkg/tcpip/stack/ndp.go')
| -rwxr-xr-x | pkg/tcpip/stack/ndp.go | 349 |
1 files changed, 62 insertions, 287 deletions
diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index 4722ec9ce..35825ebf7 100755 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -299,46 +299,14 @@ type dadState struct { // defaultRouterState holds data associated with a default router discovered by // a Router Advertisement (RA). type defaultRouterState struct { - invalidationTimer *time.Timer - - // 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 - // T1: Obtain the NIC's lock before processing the RA - // T2: R's invalidation timer fires, and gets blocked on obtaining the - // NIC's lock - // T1: Refreshes/extends R's lifetime & releases NIC's lock - // T2: Obtains NIC's lock & invalidates R immediately - // - // To resolve this, T1 will check to see if the timer already fired, and - // 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 + invalidationTimer tcpip.CancellableTimer } // 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 + invalidationTimer tcpip.CancellableTimer } // autoGenAddressState holds data associated with an address generated via @@ -348,33 +316,10 @@ type autoGenAddressState struct { // is holding state for. ref *referencedNetworkEndpoint - deprecationTimer *time.Timer - - // Used to signal the timer not to deprecate the SLAAC address in a race - // condition. Used for the same reason as doNotInvalidate, but for deprecating - // an address. - doNotDeprecate *bool + deprecationTimer tcpip.CancellableTimer + invalidationTimer tcpip.CancellableTimer - 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). + // Nonzero only when the address is not valid forever. validUntil time.Time } @@ -576,7 +521,7 @@ func (ndp *ndpState) stopDuplicateAddressDetection(addr tcpip.Address) { // handleRA handles a Router Advertisement message that arrived on the NIC // this ndp is for. Does nothing if the NIC is configured to not handle RAs. // -// The NIC that ndp belongs to and its associated stack MUST be locked. +// The NIC that ndp belongs to MUST be locked. func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { // Is the NIC configured to handle RAs at all? // @@ -605,27 +550,9 @@ func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { case ok && rl != 0: // This is an already discovered default router. Update // the invalidation timer. - timer := rtr.invalidationTimer - - // We should ALWAYS have an invalidation timer for a - // discovered router. - if timer == nil { - panic("ndphandlera: RA invalidation timer should not be nil") - } - - if !timer.Stop() { - // If we reach this point, then we know the - // timer fired after we already took the NIC - // 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.doNotInvalidate = true - } - - timer.Reset(rl) + rtr.invalidationTimer.StopLocked() + rtr.invalidationTimer.Reset(rl) + ndp.defaultRouters[ip] = rtr case ok && rl == 0: // We know about the router but it is no longer to be @@ -692,10 +619,7 @@ func (ndp *ndpState) invalidateDefaultRouter(ip tcpip.Address) { return } - rtr.invalidationTimer.Stop() - rtr.invalidationTimer = nil - *rtr.doNotInvalidate = true - rtr.doNotInvalidate = nil + rtr.invalidationTimer.StopLocked() delete(ndp.defaultRouters, ip) @@ -724,27 +648,15 @@ func (ndp *ndpState) rememberDefaultRouter(ip tcpip.Address, rl time.Duration) { return } - // Used to signal the timer not to invalidate the default router (R) in - // a race condition. See defaultRouterState.doNotInvalidate for more - // details. - var doNotInvalidate bool - - ndp.defaultRouters[ip] = defaultRouterState{ - invalidationTimer: time.AfterFunc(rl, 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 - } - + state := defaultRouterState{ + invalidationTimer: tcpip.MakeCancellableTimer(&ndp.nic.mu, func() { ndp.invalidateDefaultRouter(ip) }), - doNotInvalidate: &doNotInvalidate, } + + state.invalidationTimer.Reset(rl) + + ndp.defaultRouters[ip] = state } // rememberOnLinkPrefix remembers a newly discovered on-link prefix with IPv6 @@ -766,21 +678,17 @@ func (ndp *ndpState) rememberOnLinkPrefix(prefix tcpip.Subnet, l time.Duration) 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 + state := onLinkPrefixState{ + invalidationTimer: tcpip.MakeCancellableTimer(&ndp.nic.mu, func() { + ndp.invalidateOnLinkPrefix(prefix) + }), + } - // Only create a timer if the lifetime is not infinite. if l < header.NDPInfiniteLifetime { - timer = ndp.prefixInvalidationCallback(prefix, l, &doNotInvalidate) + state.invalidationTimer.Reset(l) } - ndp.onLinkPrefixes[prefix] = onLinkPrefixState{ - invalidationTimer: timer, - doNotInvalidate: &doNotInvalidate, - } + ndp.onLinkPrefixes[prefix] = state } // invalidateOnLinkPrefix invalidates a discovered on-link prefix. @@ -795,13 +703,7 @@ func (ndp *ndpState) invalidateOnLinkPrefix(prefix tcpip.Subnet) { return } - if s.invalidationTimer != nil { - s.invalidationTimer.Stop() - s.invalidationTimer = nil - *s.doNotInvalidate = true - } - - s.doNotInvalidate = nil + s.invalidationTimer.StopLocked() delete(ndp.onLinkPrefixes, prefix) @@ -811,28 +713,6 @@ func (ndp *ndpState) invalidateOnLinkPrefix(prefix tcpip.Subnet) { } } -// 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) - }) -} - // handleOnLinkPrefixInformation handles a Prefix Information option with // its on-link flag set, as per RFC 4861 section 6.3.4. // @@ -872,42 +752,17 @@ func (ndp *ndpState) handleOnLinkPrefixInformation(pi header.NDPPrefixInformatio // 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 - } + prefixState.invalidationTimer.StopLocked() - 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 + if vl < header.NDPInfiniteLifetime { + // Prefix is valid for a finite lifetime, reset the timer to expire after + // the new valid lifetime. + prefixState.invalidationTimer.Reset(vl) } - // We do not have a timer so just create a new one. - prefixState.invalidationTimer = ndp.prefixInvalidationCallback(prefix, vl, prefixState.doNotInvalidate) ndp.onLinkPrefixes[prefix] = prefixState } @@ -917,7 +772,7 @@ func (ndp *ndpState) handleOnLinkPrefixInformation(pi header.NDPPrefixInformatio // 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. +// The NIC that ndp belongs to MUST be locked. func (ndp *ndpState) handleAutonomousPrefixInformation(pi header.NDPPrefixInformation) { vl := pi.ValidLifetime() pl := pi.PreferredLifetime() @@ -1026,28 +881,34 @@ func (ndp *ndpState) newAutoGenAddress(prefix tcpip.Subnet, pl, vl time.Duration log.Fatalf("ndp: error when adding address %s: %s", protocolAddr, err) } - // Setup the timers to deprecate and invalidate this newly generated address. + state := autoGenAddressState{ + ref: ref, + deprecationTimer: tcpip.MakeCancellableTimer(&ndp.nic.mu, func() { + addrState, ok := ndp.autoGenAddresses[addr] + if !ok { + log.Fatalf("ndp: must have an autoGenAddressess entry for the SLAAC generated IPv6 address %s", addr) + } + addrState.ref.deprecated = true + ndp.notifyAutoGenAddressDeprecated(addr) + }), + invalidationTimer: tcpip.MakeCancellableTimer(&ndp.nic.mu, func() { + ndp.invalidateAutoGenAddress(addr) + }), + } + + // Setup the initial timers to deprecate and invalidate this newly generated + // address. - var doNotDeprecate bool - var pTimer *time.Timer if !deprecated && pl < header.NDPInfiniteLifetime { - pTimer = ndp.autoGenAddrDeprecationTimer(addr, pl, &doNotDeprecate) + state.deprecationTimer.Reset(pl) } - var doNotInvalidate bool - var vTimer *time.Timer if vl < header.NDPInfiniteLifetime { - vTimer = ndp.autoGenAddrInvalidationTimer(addr, vl, &doNotInvalidate) + state.invalidationTimer.Reset(vl) + state.validUntil = time.Now().Add(vl) } - ndp.autoGenAddresses[addr] = autoGenAddressState{ - ref: ref, - deprecationTimer: pTimer, - doNotDeprecate: &doNotDeprecate, - invalidationTimer: vTimer, - doNotInvalidate: &doNotInvalidate, - validUntil: time.Now().Add(vl), - } + ndp.autoGenAddresses[addr] = state } // refreshAutoGenAddressLifetimes refreshes the lifetime of a SLAAC generated @@ -1075,20 +936,10 @@ func (ndp *ndpState) refreshAutoGenAddressLifetimes(addr tcpip.Address, pl, vl t // If addr was preferred for some finite lifetime before, stop the deprecation // timer so it can be reset. - if t := addrState.deprecationTimer; t != nil && !t.Stop() { - *addrState.doNotDeprecate = true - } + addrState.deprecationTimer.StopLocked() - // Reset the deprecation timer. - if pl >= header.NDPInfiniteLifetime || deprecated { - // If addr is preferred forever or it has been deprecated already, there is - // no need for a deprecation timer. - addrState.deprecationTimer = nil - } else if addrState.deprecationTimer == nil { - // addr is now preferred for a finite lifetime. - addrState.deprecationTimer = ndp.autoGenAddrDeprecationTimer(addr, pl, addrState.doNotDeprecate) - } else { - // addr continues to be preferred for a finite lifetime. + // Reset the deprecation timer if addr has a finite preferred lifetime. + if !deprecated && pl < header.NDPInfiniteLifetime { addrState.deprecationTimer.Reset(pl) } @@ -1107,15 +958,8 @@ func (ndp *ndpState) refreshAutoGenAddressLifetimes(addr tcpip.Address, pl, vl t // 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{} - } - + addrState.invalidationTimer.StopLocked() + addrState.validUntil = time.Time{} return } @@ -1124,7 +968,7 @@ func (ndp *ndpState) refreshAutoGenAddressLifetimes(addr tcpip.Address, pl, vl t // If the address was originally set to be valid forever, assume the remaining // time to be the maximum possible value. - if addrState.invalidationTimer == nil { + if addrState.validUntil == (time.Time{}) { rl = header.NDPInfiniteLifetime } else { rl = time.Until(addrState.validUntil) @@ -1138,15 +982,8 @@ func (ndp *ndpState) refreshAutoGenAddressLifetimes(addr tcpip.Address, pl, vl t 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.invalidationTimer.StopLocked() + addrState.invalidationTimer.Reset(effectiveVl) addrState.validUntil = time.Now().Add(effectiveVl) } @@ -1181,27 +1018,12 @@ func (ndp *ndpState) invalidateAutoGenAddress(addr tcpip.Address) { // 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.deprecationTimer != nil { - state.deprecationTimer.Stop() - state.deprecationTimer = nil - *state.doNotDeprecate = true - } - - state.doNotDeprecate = nil - - if state.invalidationTimer != nil { - state.invalidationTimer.Stop() - state.invalidationTimer = nil - *state.doNotInvalidate = true - } - - state.doNotInvalidate = nil - + state.deprecationTimer.StopLocked() + state.invalidationTimer.StopLocked() delete(ndp.autoGenAddresses, addr) if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { @@ -1214,53 +1036,6 @@ func (ndp *ndpState) cleanupAutoGenAddrResourcesAndNotify(addr tcpip.Address) bo return true } -// autoGenAddrDeprecationTimer returns a new deprecation timer for an -// auto-generated address that fires after pl. -// -// doNotDeprecate is used to inform the timer when it fires at the same time -// that an auto-generated address's preferred lifetime gets refreshed. See -// autoGenAddrState.doNotDeprecate for more details. -func (ndp *ndpState) autoGenAddrDeprecationTimer(addr tcpip.Address, pl time.Duration, doNotDeprecate *bool) *time.Timer { - return time.AfterFunc(pl, func() { - ndp.nic.mu.Lock() - defer ndp.nic.mu.Unlock() - - if *doNotDeprecate { - *doNotDeprecate = false - return - } - - addrState, ok := ndp.autoGenAddresses[addr] - if !ok { - log.Fatalf("ndp: must have an autoGenAddressess entry for the SLAAC generated IPv6 address %s", addr) - } - addrState.ref.deprecated = true - ndp.notifyAutoGenAddressDeprecated(addr) - addrState.deprecationTimer = nil - ndp.autoGenAddresses[addr] = addrState - }) -} - -// 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) - }) -} - // cleanupHostOnlyState cleans up any state that is only useful for hosts. // // cleanupHostOnlyState MUST be called when ndp's NIC is transitioning from a |