diff options
Diffstat (limited to 'pkg/tcpip/stack/ndp.go')
| -rwxr-xr-x | pkg/tcpip/stack/ndp.go | 181 |
1 files changed, 81 insertions, 100 deletions
diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index 7d4b41dfa..d983ac390 100755 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -15,7 +15,6 @@ package stack import ( - "fmt" "log" "math/rand" "time" @@ -429,8 +428,13 @@ func (ndp *ndpState) startDuplicateAddressDetection(addr tcpip.Address, ref *ref return tcpip.ErrAddressFamilyNotSupported } - // Should not attempt to perform DAD on an address that is currently in - // the DAD process. + if ref.getKind() != permanentTentative { + // The endpoint should be marked as tentative since we are starting DAD. + log.Fatalf("ndpdad: addr %s is not tentative on NIC(%d)", addr, ndp.nic.ID()) + } + + // Should not attempt to perform DAD on an address that is currently in the + // DAD process. if _, ok := ndp.dad[addr]; ok { // Should never happen because we should only ever call this function for // newly created addresses. If we attemped to "add" an address that already @@ -438,77 +442,79 @@ func (ndp *ndpState) startDuplicateAddressDetection(addr tcpip.Address, ref *ref // address, or its reference count would have been increased without doing // the work that would have been done for an address that was brand new. // See NIC.addAddressLocked. - panic(fmt.Sprintf("ndpdad: already performing DAD for addr %s on NIC(%d)", addr, ndp.nic.ID())) + log.Fatalf("ndpdad: already performing DAD for addr %s on NIC(%d)", addr, ndp.nic.ID()) } remaining := ndp.configs.DupAddrDetectTransmits - - { - done, err := ndp.doDuplicateAddressDetection(addr, remaining, ref) - if err != nil { - return err - } - if done { - return nil - } + if remaining == 0 { + ref.setKind(permanent) + return nil } - remaining-- - var done bool var timer *time.Timer - timer = time.AfterFunc(ndp.configs.RetransmitTimer, func() { - var d bool - var err *tcpip.Error - - // doDadIteration does a single iteration of the DAD loop. - // - // Returns true if the integrator needs to be informed of DAD - // completing. - doDadIteration := func() bool { - ndp.nic.mu.Lock() - defer ndp.nic.mu.Unlock() - - if done { - // If we reach this point, it means that the DAD - // timer fired after another goroutine already - // obtained the NIC lock and stopped DAD before - // this function obtained the NIC lock. Simply - // return here and do nothing further. - return false - } + // We initially start a timer to fire immediately because some of the DAD work + // cannot be done while holding the NIC's lock. This is effectively the same + // as starting a goroutine but we use a timer that fires immediately so we can + // reset it for the next DAD iteration. + timer = time.AfterFunc(0, func() { + ndp.nic.mu.RLock() + if done { + // If we reach this point, it means that the DAD timer fired after + // another goroutine already obtained the NIC lock and stopped DAD + // before this function obtained the NIC lock. Simply return here and do + // nothing further. + ndp.nic.mu.RUnlock() + return + } - ref, ok := ndp.nic.endpoints[NetworkEndpointID{addr}] - if !ok { - // This should never happen. - // We should have an endpoint for addr since we - // are still performing DAD on it. If the - // endpoint does not exist, but we are doing DAD - // on it, then we started DAD at some point, but - // forgot to stop it when the endpoint was - // deleted. - panic(fmt.Sprintf("ndpdad: unrecognized addr %s for NIC(%d)", addr, ndp.nic.ID())) - } + if ref.getKind() != permanentTentative { + // The endpoint should still be marked as tentative since we are still + // performing DAD on it. + log.Fatalf("ndpdad: addr %s is no longer tentative on NIC(%d)", addr, ndp.nic.ID()) + } - d, err = ndp.doDuplicateAddressDetection(addr, remaining, ref) - if err != nil || d { - delete(ndp.dad, addr) + dadDone := remaining == 0 + ndp.nic.mu.RUnlock() - if err != nil { - log.Printf("ndpdad: Error occured during DAD iteration for addr (%s) on NIC(%d); err = %s", addr, ndp.nic.ID(), err) - } + var err *tcpip.Error + if !dadDone { + err = ndp.sendDADPacket(addr) + } - // Let the integrator know DAD has completed. - return true - } + ndp.nic.mu.Lock() + if done { + // If we reach this point, it means that DAD was stopped after we released + // the NIC's read lock and before we obtained the write lock. + ndp.nic.mu.Unlock() + return + } + if dadDone { + // DAD has resolved. + ref.setKind(permanent) + } else if err == nil { + // DAD is not done and we had no errors when sending the last NDP NS, + // schedule the next DAD timer. remaining-- timer.Reset(ndp.nic.stack.ndpConfigs.RetransmitTimer) - return false + + ndp.nic.mu.Unlock() + return + } + + // At this point we know that either DAD is done or we hit an error sending + // the last NDP NS. Either way, clean up addr's DAD state and let the + // integrator know DAD has completed. + delete(ndp.dad, addr) + ndp.nic.mu.Unlock() + + if err != nil { + log.Printf("ndpdad: error occured during DAD iteration for addr (%s) on NIC(%d); err = %s", addr, ndp.nic.ID(), err) } - if doDadIteration() && ndp.nic.stack.ndpDisp != nil { - ndp.nic.stack.ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, d, err) + if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { + ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, dadDone, err) } }) @@ -520,45 +526,16 @@ func (ndp *ndpState) startDuplicateAddressDetection(addr tcpip.Address, ref *ref return nil } -// doDuplicateAddressDetection is called on every iteration of the timer, and -// when DAD starts. -// -// It handles resolving the address (if there are no more NS to send), or -// sending the next NS if there are more NS to send. -// -// This function must only be called by IPv6 addresses that are currently -// tentative. -// -// The NIC that ndp belongs to (n) MUST be locked. +// sendDADPacket sends a NS message to see if any nodes on ndp's NIC's link owns +// addr. // -// Returns true if DAD has resolved; false if DAD is still ongoing. -func (ndp *ndpState) doDuplicateAddressDetection(addr tcpip.Address, remaining uint8, ref *referencedNetworkEndpoint) (bool, *tcpip.Error) { - if ref.getKind() != permanentTentative { - // The endpoint should still be marked as tentative - // since we are still performing DAD on it. - panic(fmt.Sprintf("ndpdad: addr %s is not tentative on NIC(%d)", addr, ndp.nic.ID())) - } - - if remaining == 0 { - // DAD has resolved. - ref.setKind(permanent) - return true, nil - } - - // Send a new NS. +// addr must be a tentative IPv6 address on ndp's NIC. +func (ndp *ndpState) sendDADPacket(addr tcpip.Address) *tcpip.Error { snmc := header.SolicitedNodeAddr(addr) - snmcRef, ok := ndp.nic.endpoints[NetworkEndpointID{snmc}] - if !ok { - // This should never happen as if we have the - // address, we should have the solicited-node - // address. - panic(fmt.Sprintf("ndpdad: NIC(%d) is not in the solicited-node multicast group (%s) but it has addr %s", ndp.nic.ID(), snmc, addr)) - } - snmcRef.incRef() - // Use the unspecified address as the source address when performing - // DAD. - r := makeRoute(header.IPv6ProtocolNumber, header.IPv6Any, snmc, ndp.nic.linkEP.LinkAddress(), snmcRef, false, false) + // Use the unspecified address as the source address when performing DAD. + ref := ndp.nic.getRefOrCreateTemp(header.IPv6ProtocolNumber, header.IPv6Any, NeverPrimaryEndpoint, forceSpoofing) + 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) @@ -569,15 +546,19 @@ func (ndp *ndpState) doDuplicateAddressDetection(addr tcpip.Address, remaining u pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{})) sent := r.Stats().ICMP.V6PacketsSent - if err := r.WritePacket(nil, NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: header.NDPHopLimit, TOS: DefaultTOS}, tcpip.PacketBuffer{ - Header: hdr, - }); err != nil { + if err := r.WritePacket(nil, + NetworkHeaderParams{ + Protocol: header.ICMPv6ProtocolNumber, + TTL: header.NDPHopLimit, + TOS: DefaultTOS, + }, tcpip.PacketBuffer{Header: hdr}, + ); err != nil { sent.Dropped.Increment() - return false, err + return err } sent.NeighborSolicit.Increment() - return false, nil + return nil } // stopDuplicateAddressDetection ends a running Duplicate Address Detection @@ -1212,7 +1193,7 @@ func (ndp *ndpState) startSolicitingRouters() { ndp.rtrSolicitTimer = time.AfterFunc(delay, func() { // Send an RS message with the unspecified source address. - ref := ndp.nic.getRefOrCreateTemp(header.IPv6ProtocolNumber, header.IPv6Any, NeverPrimaryEndpoint, true) + ref := ndp.nic.getRefOrCreateTemp(header.IPv6ProtocolNumber, header.IPv6Any, NeverPrimaryEndpoint, forceSpoofing) r := makeRoute(header.IPv6ProtocolNumber, header.IPv6Any, header.IPv6AllRoutersMulticastAddress, ndp.nic.linkEP.LinkAddress(), ref, false, false) defer r.Release() |