diff options
Diffstat (limited to 'pkg/tcpip/stack/nic.go')
| -rw-r--r-- | pkg/tcpip/stack/nic.go | 110 |
1 files changed, 97 insertions, 13 deletions
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index ca3a7a07e..b2be18e47 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -27,6 +27,14 @@ import ( "gvisor.dev/gvisor/pkg/tcpip/header" ) +var ipv4BroadcastAddr = tcpip.ProtocolAddress{ + Protocol: header.IPv4ProtocolNumber, + AddressWithPrefix: tcpip.AddressWithPrefix{ + Address: header.IPv4Broadcast, + PrefixLen: 8 * header.IPv4AddressSize, + }, +} + // NIC represents a "network interface card" to which the networking stack is // attached. type NIC struct { @@ -36,7 +44,8 @@ type NIC struct { linkEP LinkEndpoint context NICContext - stats NICStats + stats NICStats + attach sync.Once mu struct { sync.RWMutex @@ -135,7 +144,69 @@ func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, ctx NICC return nic } -// enable enables the NIC. enable will attach the link to its LinkEndpoint and +// enabled returns true if n is enabled. +func (n *NIC) enabled() bool { + n.mu.RLock() + enabled := n.mu.enabled + n.mu.RUnlock() + return enabled +} + +// disable disables n. +// +// It undoes the work done by enable. +func (n *NIC) disable() *tcpip.Error { + n.mu.RLock() + enabled := n.mu.enabled + n.mu.RUnlock() + if !enabled { + return nil + } + + n.mu.Lock() + defer n.mu.Unlock() + + if !n.mu.enabled { + return nil + } + + // TODO(b/147015577): Should Routes that are currently bound to n be + // invalidated? Currently, Routes will continue to work when a NIC is enabled + // again, and applications may not know that the underlying NIC was ever + // disabled. + + if _, ok := n.stack.networkProtocols[header.IPv6ProtocolNumber]; ok { + n.mu.ndp.stopSolicitingRouters() + n.mu.ndp.cleanupState(false /* hostOnly */) + + // Stop DAD for all the unicast IPv6 endpoints that are in the + // permanentTentative state. + for _, r := range n.mu.endpoints { + if addr := r.ep.ID().LocalAddress; r.getKind() == permanentTentative && header.IsV6UnicastAddress(addr) { + n.mu.ndp.stopDuplicateAddressDetection(addr) + } + } + + // The NIC may have already left the multicast group. + if err := n.leaveGroupLocked(header.IPv6AllNodesMulticastAddress); err != nil && err != tcpip.ErrBadLocalAddress { + return err + } + } + + if _, ok := n.stack.networkProtocols[header.IPv4ProtocolNumber]; ok { + // The address may have already been removed. + if err := n.removePermanentAddressLocked(ipv4BroadcastAddr.AddressWithPrefix.Address); err != nil && err != tcpip.ErrBadLocalAddress { + return err + } + } + + // TODO(b/147015577): Should n detach from its LinkEndpoint? + + n.mu.enabled = false + return nil +} + +// enable enables n. enable will attach the nic to its LinkEndpoint and // join the IPv6 All-Nodes Multicast address (ff02::1). func (n *NIC) enable() *tcpip.Error { n.mu.RLock() @@ -158,10 +229,7 @@ func (n *NIC) enable() *tcpip.Error { // Create an endpoint to receive broadcast packets on this interface. if _, ok := n.stack.networkProtocols[header.IPv4ProtocolNumber]; ok { - if _, err := n.addAddressLocked(tcpip.ProtocolAddress{ - Protocol: header.IPv4ProtocolNumber, - AddressWithPrefix: tcpip.AddressWithPrefix{header.IPv4Broadcast, 8 * header.IPv4AddressSize}, - }, NeverPrimaryEndpoint, permanent, static, false /* deprecated */); err != nil { + if _, err := n.addAddressLocked(ipv4BroadcastAddr, NeverPrimaryEndpoint, permanent, static, false /* deprecated */); err != nil { return err } } @@ -183,6 +251,14 @@ func (n *NIC) enable() *tcpip.Error { return nil } + // Join the All-Nodes multicast group before starting DAD as responses to DAD + // (NDP NS) messages may be sent to the All-Nodes multicast group if the + // source address of the NDP NS is the unspecified address, as per RFC 4861 + // section 7.2.4. + if err := n.joinGroupLocked(header.IPv6ProtocolNumber, header.IPv6AllNodesMulticastAddress); err != nil { + return err + } + // Perform DAD on the all the unicast IPv6 endpoints that are in the permanent // state. // @@ -200,10 +276,6 @@ func (n *NIC) enable() *tcpip.Error { } } - if err := n.joinGroupLocked(header.IPv6ProtocolNumber, header.IPv6AllNodesMulticastAddress); err != nil { - return err - } - // Do not auto-generate an IPv6 link-local address for loopback devices. if n.stack.autoGenIPv6LinkLocal && !n.isLoopback() { // The valid and preferred lifetime is infinite for the auto-generated @@ -234,7 +306,7 @@ func (n *NIC) becomeIPv6Router() { n.mu.Lock() defer n.mu.Unlock() - n.mu.ndp.cleanupHostOnlyState() + n.mu.ndp.cleanupState(true /* hostOnly */) n.mu.ndp.stopSolicitingRouters() } @@ -252,7 +324,9 @@ func (n *NIC) becomeIPv6Host() { // attachLinkEndpoint attaches the NIC to the endpoint, which will enable it // to start delivering packets. func (n *NIC) attachLinkEndpoint() { - n.linkEP.Attach(n) + n.attach.Do(func() { + n.linkEP.Attach(n) + }) } // setPromiscuousMode enables or disables promiscuous mode. @@ -712,6 +786,7 @@ func (n *NIC) AllAddresses() []tcpip.ProtocolAddress { case permanentExpired, temporary: continue } + addrs = append(addrs, tcpip.ProtocolAddress{ Protocol: ref.protocol, AddressWithPrefix: tcpip.AddressWithPrefix{ @@ -1009,6 +1084,15 @@ func (n *NIC) leaveGroupLocked(addr tcpip.Address) *tcpip.Error { return nil } +// isInGroup returns true if n has joined the multicast group addr. +func (n *NIC) isInGroup(addr tcpip.Address) bool { + n.mu.RLock() + joins := n.mu.mcastJoins[NetworkEndpointID{addr}] + n.mu.RUnlock() + + return joins != 0 +} + func handlePacket(protocol tcpip.NetworkProtocolNumber, dst, src tcpip.Address, localLinkAddr, remotelinkAddr tcpip.LinkAddress, ref *referencedNetworkEndpoint, pkt tcpip.PacketBuffer) { r := makeRoute(protocol, dst, src, localLinkAddr, ref, false /* handleLocal */, false /* multicastLoop */) r.RemoteLinkAddress = remotelinkAddr @@ -1411,7 +1495,7 @@ func (r *referencedNetworkEndpoint) isValidForOutgoing() bool { // // r's NIC must be read locked. func (r *referencedNetworkEndpoint) isValidForOutgoingRLocked() bool { - return r.getKind() != permanentExpired || r.nic.mu.spoofing + return r.nic.mu.enabled && (r.getKind() != permanentExpired || r.nic.mu.spoofing) } // decRef decrements the ref count and cleans up the endpoint once it reaches |