diff options
Diffstat (limited to 'pkg/tcpip/stack/nic.go')
| -rw-r--r-- | pkg/tcpip/stack/nic.go | 71 |
1 files changed, 66 insertions, 5 deletions
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index 43719085e..a719058b4 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -102,6 +102,25 @@ func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, loopback } } +// enable enables the NIC. enable will attach the link to its LinkEndpoint and +// join the IPv6 All-Nodes Multicast address (ff02::1). +func (n *NIC) enable() *tcpip.Error { + n.attachLinkEndpoint() + + // Join the IPv6 All-Nodes Multicast group if the stack is configured to + // use IPv6. This is required to ensure that this node properly receives + // and responds to the various NDP messages that are destined to the + // all-nodes multicast address. An example is the Neighbor Advertisement + // when we perform Duplicate Address Detection, or Router Advertisement + // when we do Router Discovery. See RFC 4862, section 5.4.2 and RFC 4861 + // section 4.2 for more information. + if _, ok := n.stack.networkProtocols[header.IPv6ProtocolNumber]; ok { + return n.joinGroup(header.IPv6ProtocolNumber, header.IPv6AllNodesMulticastAddress) + } + + return nil +} + // attachLinkEndpoint attaches the NIC to the endpoint, which will enable it // to start delivering packets. func (n *NIC) attachLinkEndpoint() { @@ -307,6 +326,8 @@ func (n *NIC) addPermanentAddressLocked(protocolAddress tcpip.ProtocolAddress, p } func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior, kind networkEndpointKind) (*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 { @@ -339,6 +360,15 @@ func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb Primar } } + // If we are adding an IPv6 unicast address, join the solicited-node + // multicast address. + if protocolAddress.Protocol == header.IPv6ProtocolNumber && header.IsV6UnicastAddress(protocolAddress.AddressWithPrefix.Address) { + snmc := header.SolicitedNodeAddr(protocolAddress.AddressWithPrefix.Address) + if err := n.joinGroupLocked(protocolAddress.Protocol, snmc); err != nil { + return nil, err + } + } + n.endpoints[id] = ref l, ok := n.primary[protocolAddress.Protocol] @@ -467,13 +497,27 @@ func (n *NIC) removeEndpoint(r *referencedNetworkEndpoint) { } func (n *NIC) removePermanentAddressLocked(addr tcpip.Address) *tcpip.Error { - r := n.endpoints[NetworkEndpointID{addr}] - if r == nil || r.getKind() != permanent { + r, ok := n.endpoints[NetworkEndpointID{addr}] + if !ok || r.getKind() != permanent { return tcpip.ErrBadLocalAddress } r.setKind(permanentExpired) - r.decRefLocked() + if !r.decRefLocked() { + // The endpoint still has references to it. + return nil + } + + // At this point the endpoint is deleted. + + // If we are removing an IPv6 unicast address, leave the solicited-node + // multicast address. + if r.protocol == header.IPv6ProtocolNumber && header.IsV6UnicastAddress(addr) { + snmc := header.SolicitedNodeAddr(addr) + if err := n.leaveGroupLocked(snmc); err != nil { + return err + } + } return nil } @@ -491,6 +535,13 @@ func (n *NIC) joinGroup(protocol tcpip.NetworkProtocolNumber, addr tcpip.Address n.mu.Lock() defer n.mu.Unlock() + return n.joinGroupLocked(protocol, addr) +} + +// joinGroupLocked adds a new endpoint for the given multicast address, if none +// exists yet. Otherwise it just increments its count. n MUST be locked before +// joinGroupLocked is called. +func (n *NIC) joinGroupLocked(protocol tcpip.NetworkProtocolNumber, addr tcpip.Address) *tcpip.Error { id := NetworkEndpointID{addr} joins := n.mcastJoins[id] if joins == 0 { @@ -518,6 +569,13 @@ func (n *NIC) leaveGroup(addr tcpip.Address) *tcpip.Error { n.mu.Lock() defer n.mu.Unlock() + return n.leaveGroupLocked(addr) +} + +// leaveGroupLocked decrements the count for the given multicast address, and +// when it reaches zero removes the endpoint for this address. n MUST be locked +// before leaveGroupLocked is called. +func (n *NIC) leaveGroupLocked(addr tcpip.Address) *tcpip.Error { id := NetworkEndpointID{addr} joins := n.mcastJoins[id] switch joins { @@ -802,11 +860,14 @@ func (r *referencedNetworkEndpoint) decRef() { } // decRefLocked is the same as decRef but assumes that the NIC.mu mutex is -// locked. -func (r *referencedNetworkEndpoint) decRefLocked() { +// locked. Returns true if the endpoint was removed. +func (r *referencedNetworkEndpoint) decRefLocked() bool { if atomic.AddInt32(&r.refs, -1) == 0 { r.nic.removeEndpointLocked(r) + return true } + + return false } // incRef increments the ref count. It must only be called when the caller is |