diff options
Diffstat (limited to 'pkg/tcpip/network/ipv4/igmp.go')
| -rw-r--r-- | pkg/tcpip/network/ipv4/igmp.go | 57 |
1 files changed, 49 insertions, 8 deletions
diff --git a/pkg/tcpip/network/ipv4/igmp.go b/pkg/tcpip/network/ipv4/igmp.go index c9bf117de..37f1822ca 100644 --- a/pkg/tcpip/network/ipv4/igmp.go +++ b/pkg/tcpip/network/ipv4/igmp.go @@ -51,6 +51,16 @@ const ( UnsolicitedReportIntervalMax = 10 * time.Second ) +// IGMPOptions holds options for IGMP. +type IGMPOptions struct { + // Enabled indicates whether IGMP will be performed. + // + // When enabled, IGMP may transmit IGMP report and leave messages when + // joining and leaving multicast groups respectively, and handle incoming + // IGMP packets. + Enabled bool +} + var _ ip.MulticastGroupProtocol = (*igmpState)(nil) // igmpState is the per-interface IGMP state. @@ -58,7 +68,8 @@ var _ ip.MulticastGroupProtocol = (*igmpState)(nil) // igmpState.init() MUST be called after creating an IGMP state. type igmpState struct { // The IPv4 endpoint this igmpState is for. - ep *endpoint + ep *endpoint + opts IGMPOptions // igmpV1Present is for maintaining compatibility with IGMPv1 Routers, from // RFC 2236 Section 4 Page 6: "The IGMPv1 router expects Version 1 @@ -108,10 +119,11 @@ func (igmp *igmpState) SendLeave(groupAddress tcpip.Address) *tcpip.Error { // init sets up an igmpState struct, and is required to be called before using // a new igmpState. -func (igmp *igmpState) init(ep *endpoint) { +func (igmp *igmpState) init(ep *endpoint, opts IGMPOptions) { igmp.mu.Lock() defer igmp.mu.Unlock() igmp.ep = ep + igmp.opts = opts igmp.mu.genericMulticastProtocol.Init(ep.protocol.stack.Rand(), ep.protocol.stack.Clock(), igmp, UnsolicitedReportIntervalMax) igmp.igmpV1Present = igmpV1PresentDefault igmp.mu.igmpV1Job = igmp.ep.protocol.stack.NewJob(&igmp.mu, func() { @@ -189,6 +201,10 @@ func (igmp *igmpState) setV1Present(v bool) { } func (igmp *igmpState) handleMembershipQuery(groupAddress tcpip.Address, maxRespTime time.Duration) { + if !igmp.opts.Enabled { + return + } + igmp.mu.Lock() defer igmp.mu.Unlock() @@ -206,6 +222,10 @@ func (igmp *igmpState) handleMembershipQuery(groupAddress tcpip.Address, maxResp } func (igmp *igmpState) handleMembershipReport(groupAddress tcpip.Address) { + if !igmp.opts.Enabled { + return + } + igmp.mu.Lock() defer igmp.mu.Unlock() igmp.mu.genericMulticastProtocol.HandleReport(groupAddress) @@ -226,11 +246,8 @@ func (igmp *igmpState) writePacket(destAddress tcpip.Address, groupAddress tcpip // TODO(gvisor.dev/issue/4888): We should not use the unspecified address, // rather we should select an appropriate local address. - r := stack.Route{ - LocalAddress: header.IPv4Any, - RemoteAddress: destAddress, - } - igmp.ep.addIPHeader(&r, pkt, stack.NetworkHeaderParams{ + localAddr := header.IPv4Any + igmp.ep.addIPHeader(localAddr, destAddress, pkt, stack.NetworkHeaderParams{ Protocol: header.IGMPProtocolNumber, TTL: header.IGMPTTL, TOS: stack.DefaultTOS, @@ -239,7 +256,7 @@ func (igmp *igmpState) writePacket(destAddress tcpip.Address, groupAddress tcpip // TODO(b/162198658): set the ROUTER_ALERT option when sending Host // Membership Reports. sent := igmp.ep.protocol.stack.Stats().IGMP.PacketsSent - if err := igmp.ep.nic.WritePacketToRemote(header.EthernetAddressFromMulticastIPv4Address(destAddress), nil /* gso */, header.IPv4ProtocolNumber, pkt); err != nil { + if err := igmp.ep.nic.WritePacketToRemote(header.EthernetAddressFromMulticastIPv4Address(destAddress), nil /* gso */, ProtocolNumber, pkt); err != nil { sent.Dropped.Increment() return err } @@ -263,6 +280,26 @@ func (igmp *igmpState) writePacket(destAddress tcpip.Address, groupAddress tcpip // If the group already exists in the membership map, returns // tcpip.ErrDuplicateAddress. func (igmp *igmpState) joinGroup(groupAddress tcpip.Address) *tcpip.Error { + if !igmp.opts.Enabled { + return nil + } + + // As per RFC 2236 section 6 page 10, + // + // The all-systems group (address 224.0.0.1) is handled as a special + // case. The host starts in Idle Member state for that group on every + // interface, never transitions to another state, and never sends a + // report for that group. + // + // This is equivalent to not performing IGMP for the all-systems multicast + // address. Simply not performing IGMP when the group is added will prevent + // any work from being done on the all-systems multicast group when leaving + // the group or when query or report messages are received for it since the + // MGP state will not know about it. + if groupAddress == header.IPv4AllSystems { + return nil + } + igmp.mu.Lock() defer igmp.mu.Unlock() @@ -280,6 +317,10 @@ func (igmp *igmpState) joinGroup(groupAddress tcpip.Address) *tcpip.Error { // If the group does not exist in the membership map, this function will // silently return. func (igmp *igmpState) leaveGroup(groupAddress tcpip.Address) { + if !igmp.opts.Enabled { + return + } + igmp.mu.Lock() defer igmp.mu.Unlock() igmp.mu.genericMulticastProtocol.LeaveGroup(groupAddress) |