diff options
Diffstat (limited to 'pkg/tcpip/stack/ndp.go')
| -rw-r--r-- | pkg/tcpip/stack/ndp.go | 118 |
1 files changed, 79 insertions, 39 deletions
diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index 921d1c9c7..ea2dbed2e 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -51,6 +51,22 @@ const ( minimumRetransmitTimer = time.Millisecond ) +// NDPDispatcher is the interface integrators of netstack must implement to +// receive and handle NDP related events. +type NDPDispatcher interface { + // OnDuplicateAddressDetectionStatus will be called when the DAD process + // for an address (addr) on a NIC (with ID nicid) completes. resolved + // will be set to true if DAD completed successfully (no duplicate addr + // detected); false otherwise (addr was detected to be a duplicate on + // the link the NIC is a part of, or it was stopped for some other + // reason, such as the address being removed). If an error occured + // during DAD, err will be set and resolved must be ignored. + // + // This function is permitted to block indefinitely without interfering + // with the stack's operation. + OnDuplicateAddressDetectionStatus(nicid tcpip.NICID, addr tcpip.Address, resolved bool, err *tcpip.Error) +} + // NDPConfigurations is the NDP configurations for the netstack. type NDPConfigurations struct { // The number of Neighbor Solicitation messages to send when doing @@ -88,6 +104,9 @@ func (c *NDPConfigurations) validate() { // ndpState is the per-interface NDP state. type ndpState struct { + // The NIC this ndpState is for. + nic *NIC + // The DAD state to send the next NS message, or resolve the address. dad map[tcpip.Address]dadState } @@ -110,8 +129,8 @@ type dadState struct { // This function must only be called by IPv6 addresses that are currently // tentative. // -// The NIC that ndp belongs to (n) MUST be locked. -func (ndp *ndpState) startDuplicateAddressDetection(n *NIC, addr tcpip.Address, ref *referencedNetworkEndpoint) *tcpip.Error { +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) startDuplicateAddressDetection(addr tcpip.Address, ref *referencedNetworkEndpoint) *tcpip.Error { // addr must be a valid unicast IPv6 address. if !header.IsV6UnicastAddress(addr) { return tcpip.ErrAddressFamilyNotSupported @@ -127,13 +146,13 @@ func (ndp *ndpState) startDuplicateAddressDetection(n *NIC, addr tcpip.Address, // reference count would have been increased without doing the // work that would have been done for an address that was brand // new. See NIC.addPermanentAddressLocked. - panic(fmt.Sprintf("ndpdad: already performing DAD for addr %s on NIC(%d)", addr, n.ID())) + panic(fmt.Sprintf("ndpdad: already performing DAD for addr %s on NIC(%d)", addr, ndp.nic.ID())) } - remaining := n.stack.ndpConfigs.DupAddrDetectTransmits + remaining := ndp.nic.stack.ndpConfigs.DupAddrDetectTransmits { - done, err := ndp.doDuplicateAddressDetection(n, addr, remaining, ref) + done, err := ndp.doDuplicateAddressDetection(addr, remaining, ref) if err != nil { return err } @@ -146,41 +165,59 @@ func (ndp *ndpState) startDuplicateAddressDetection(n *NIC, addr tcpip.Address, var done bool var timer *time.Timer - timer = time.AfterFunc(n.stack.ndpConfigs.RetransmitTimer, func() { - n.mu.Lock() - defer n.mu.Unlock() + timer = time.AfterFunc(ndp.nic.stack.ndpConfigs.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 + } - 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 it this function - // obtained the NIC lock. Simply return here and do - // nothing further. - 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())) + } - ref, ok := n.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, n.ID())) - } + d, err = ndp.doDuplicateAddressDetection(addr, remaining, ref) + if err != nil || d { + delete(ndp.dad, addr) - if done, err := ndp.doDuplicateAddressDetection(n, addr, remaining, ref); err != nil || done { - if err != nil { - log.Printf("ndpdad: Error occured during DAD iteration for addr (%s) on NIC(%d); err = %s", addr, n.ID(), err) + if err != nil { + log.Printf("ndpdad: Error occured during DAD iteration for addr (%s) on NIC(%d); err = %s", addr, ndp.nic.ID(), err) + } + + // Let the integrator know DAD has completed. + return true } - ndp.stopDuplicateAddressDetection(addr) - return + remaining-- + timer.Reset(ndp.nic.stack.ndpConfigs.RetransmitTimer) + return false } - timer.Reset(n.stack.ndpConfigs.RetransmitTimer) - remaining-- + if doDadIteration() && ndp.nic.stack.ndpDisp != nil { + ndp.nic.stack.ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, d, err) + } }) @@ -204,11 +241,11 @@ func (ndp *ndpState) startDuplicateAddressDetection(n *NIC, addr tcpip.Address, // The NIC that ndp belongs to (n) MUST be locked. // // Returns true if DAD has resolved; false if DAD is still ongoing. -func (ndp *ndpState) doDuplicateAddressDetection(n *NIC, addr tcpip.Address, remaining uint8, ref *referencedNetworkEndpoint) (bool, *tcpip.Error) { +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, n.ID())) + panic(fmt.Sprintf("ndpdad: addr %s is not tentative on NIC(%d)", addr, ndp.nic.ID())) } if remaining == 0 { @@ -219,17 +256,17 @@ func (ndp *ndpState) doDuplicateAddressDetection(n *NIC, addr tcpip.Address, rem // Send a new NS. snmc := header.SolicitedNodeAddr(addr) - snmcRef, ok := n.endpoints[NetworkEndpointID{snmc}] + 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", n.ID(), snmc, addr)) + 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)) } // Use the unspecified address as the source address when performing // DAD. - r := makeRoute(header.IPv6ProtocolNumber, header.IPv6Any, snmc, n.linkEP.LinkAddress(), snmcRef, false, false) + r := makeRoute(header.IPv6ProtocolNumber, header.IPv6Any, snmc, ndp.nic.linkEP.LinkAddress(), snmcRef, false, false) hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv6NeighborSolicitMinimumSize) pkt := header.ICMPv6(hdr.Prepend(header.ICMPv6NeighborSolicitMinimumSize)) @@ -275,5 +312,8 @@ func (ndp *ndpState) stopDuplicateAddressDetection(addr tcpip.Address) { delete(ndp.dad, addr) - return + // Let the integrator know DAD did not resolve. + if ndp.nic.stack.ndpDisp != nil { + go ndp.nic.stack.ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, false, nil) + } } |