diff options
Diffstat (limited to 'pkg/tcpip/stack/nic.go')
| -rw-r--r-- | pkg/tcpip/stack/nic.go | 92 |
1 files changed, 69 insertions, 23 deletions
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index ec8e3cb85..644c0d437 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -457,8 +457,20 @@ type ipv6AddrCandidate struct { // remoteAddr must be a valid IPv6 address. func (n *NIC) primaryIPv6Endpoint(remoteAddr tcpip.Address) *referencedNetworkEndpoint { n.mu.RLock() - defer n.mu.RUnlock() + ref := n.primaryIPv6EndpointRLocked(remoteAddr) + n.mu.RUnlock() + return ref +} +// primaryIPv6EndpointLocked returns an IPv6 endpoint following Source Address +// Selection (RFC 6724 section 5). +// +// Note, only rules 1-3 and 7 are followed. +// +// remoteAddr must be a valid IPv6 address. +// +// n.mu MUST be read locked. +func (n *NIC) primaryIPv6EndpointRLocked(remoteAddr tcpip.Address) *referencedNetworkEndpoint { primaryAddrs := n.mu.primary[header.IPv6ProtocolNumber] if len(primaryAddrs) == 0 { @@ -568,11 +580,6 @@ const ( // promiscuous indicates that the NIC's promiscuous flag should be observed // when getting a NIC's referenced network endpoint. promiscuous - - // forceSpoofing indicates that the NIC should be assumed to be spoofing, - // regardless of what the NIC's spoofing flag is when getting a NIC's - // referenced network endpoint. - forceSpoofing ) func (n *NIC) getRef(protocol tcpip.NetworkProtocolNumber, dst tcpip.Address) *referencedNetworkEndpoint { @@ -591,8 +598,6 @@ func (n *NIC) findEndpoint(protocol tcpip.NetworkProtocolNumber, address tcpip.A // or spoofing. Promiscuous mode will only be checked if promiscuous is true. // Similarly, spoofing will only be checked if spoofing is true. func (n *NIC) getRefOrCreateTemp(protocol tcpip.NetworkProtocolNumber, address tcpip.Address, peb PrimaryEndpointBehavior, tempRef getRefBehaviour) *referencedNetworkEndpoint { - id := NetworkEndpointID{address} - n.mu.RLock() var spoofingOrPromiscuous bool @@ -601,11 +606,9 @@ func (n *NIC) getRefOrCreateTemp(protocol tcpip.NetworkProtocolNumber, address t spoofingOrPromiscuous = n.mu.spoofing case promiscuous: spoofingOrPromiscuous = n.mu.promiscuous - case forceSpoofing: - spoofingOrPromiscuous = true } - if ref, ok := n.mu.endpoints[id]; ok { + if ref, ok := n.mu.endpoints[NetworkEndpointID{address}]; ok { // An endpoint with this id exists, check if it can be used and return it. switch ref.getKind() { case permanentExpired: @@ -654,11 +657,18 @@ func (n *NIC) getRefOrCreateTemp(protocol tcpip.NetworkProtocolNumber, address t // endpoint, create a new "temporary" endpoint. It will only exist while // there's a route through it. n.mu.Lock() - if ref, ok := n.mu.endpoints[id]; ok { + ref := n.getRefOrCreateTempLocked(protocol, address, peb) + n.mu.Unlock() + return ref +} + +/// getRefOrCreateTempLocked returns an existing endpoint for address or creates +/// and returns a temporary endpoint. +func (n *NIC) getRefOrCreateTempLocked(protocol tcpip.NetworkProtocolNumber, address tcpip.Address, peb PrimaryEndpointBehavior) *referencedNetworkEndpoint { + if ref, ok := n.mu.endpoints[NetworkEndpointID{address}]; ok { // No need to check the type as we are ok with expired endpoints at this // point. if ref.tryIncRef() { - n.mu.Unlock() return ref } // tryIncRef failing means the endpoint is scheduled to be removed once the @@ -670,7 +680,6 @@ func (n *NIC) getRefOrCreateTemp(protocol tcpip.NetworkProtocolNumber, address t // Add a new temporary endpoint. netProto, ok := n.stack.networkProtocols[protocol] if !ok { - n.mu.Unlock() return nil } ref, _ := n.addAddressLocked(tcpip.ProtocolAddress{ @@ -681,7 +690,6 @@ func (n *NIC) getRefOrCreateTemp(protocol tcpip.NetworkProtocolNumber, address t }, }, peb, temporary, static, false) - n.mu.Unlock() return ref } @@ -1212,12 +1220,21 @@ func (n *NIC) DeliverNetworkPacket(remote, local tcpip.LinkAddress, protocol tcp n.stack.stats.IP.PacketsReceived.Increment() } - netHeader, ok := pkt.Data.PullUp(netProto.MinimumPacketSize()) + // Parse headers. + transProtoNum, hasTransportHdr, ok := netProto.Parse(pkt) if !ok { + // The packet is too small to contain a network header. n.stack.stats.MalformedRcvdPackets.Increment() return } - src, dst := netProto.ParseAddresses(netHeader) + if hasTransportHdr { + // Parse the transport header if present. + if state, ok := n.stack.transportProtocols[transProtoNum]; ok { + state.proto.Parse(pkt) + } + } + + src, dst := netProto.ParseAddresses(pkt.NetworkHeader) if n.stack.handleLocal && !n.isLoopback() && n.getRef(protocol, src) != nil { // The source address is one of our own, so we never should have gotten a @@ -1229,7 +1246,8 @@ func (n *NIC) DeliverNetworkPacket(remote, local tcpip.LinkAddress, protocol tcp } // TODO(gvisor.dev/issue/170): Not supporting iptables for IPv6 yet. - if protocol == header.IPv4ProtocolNumber { + // Loopback traffic skips the prerouting chain. + if protocol == header.IPv4ProtocolNumber && !n.isLoopback() { // iptables filtering. ipt := n.stack.IPTables() address := n.primaryAddress(protocol) @@ -1300,8 +1318,18 @@ func (n *NIC) DeliverNetworkPacket(remote, local tcpip.LinkAddress, protocol tcp func (n *NIC) forwardPacket(r *Route, protocol tcpip.NetworkProtocolNumber, pkt *PacketBuffer) { // TODO(b/143425874) Decrease the TTL field in forwarded packets. - if linkHeaderLen := int(n.linkEP.MaxHeaderLength()); linkHeaderLen != 0 { - pkt.Header = buffer.NewPrependable(linkHeaderLen) + // TODO(b/151227689): Avoid copying the packet when forwarding. We can do this + // by having lower layers explicity write each header instead of just + // pkt.Header. + + // pkt may have set its NetworkHeader and TransportHeader. If we're + // forwarding, we'll have to copy them into pkt.Header. + pkt.Header = buffer.NewPrependable(int(n.linkEP.MaxHeaderLength()) + len(pkt.NetworkHeader) + len(pkt.TransportHeader)) + if n := copy(pkt.Header.Prepend(len(pkt.TransportHeader)), pkt.TransportHeader); n != len(pkt.TransportHeader) { + panic(fmt.Sprintf("copied %d bytes, expected %d", n, len(pkt.TransportHeader))) + } + if n := copy(pkt.Header.Prepend(len(pkt.NetworkHeader)), pkt.NetworkHeader); n != len(pkt.NetworkHeader) { + panic(fmt.Sprintf("copied %d bytes, expected %d", n, len(pkt.NetworkHeader))) } // WritePacket takes ownership of pkt, calculate numBytes first. @@ -1332,13 +1360,31 @@ func (n *NIC) DeliverTransportPacket(r *Route, protocol tcpip.TransportProtocolN // validly formed. n.stack.demux.deliverRawPacket(r, protocol, pkt) - transHeader, ok := pkt.Data.PullUp(transProto.MinimumPacketSize()) - if !ok { + // TransportHeader is nil only when pkt is an ICMP packet or was reassembled + // from fragments. + if pkt.TransportHeader == nil { + // TODO(gvisor.dev/issue/170): ICMP packets don't have their + // TransportHeader fields set. See icmp/protocol.go:protocol.Parse for a + // full explanation. + if protocol == header.ICMPv4ProtocolNumber || protocol == header.ICMPv6ProtocolNumber { + transHeader, ok := pkt.Data.PullUp(transProto.MinimumPacketSize()) + if !ok { + n.stack.stats.MalformedRcvdPackets.Increment() + return + } + pkt.TransportHeader = transHeader + } else { + // This is either a bad packet or was re-assembled from fragments. + transProto.Parse(pkt) + } + } + + if len(pkt.TransportHeader) < transProto.MinimumPacketSize() { n.stack.stats.MalformedRcvdPackets.Increment() return } - srcPort, dstPort, err := transProto.ParsePorts(transHeader) + srcPort, dstPort, err := transProto.ParsePorts(pkt.TransportHeader) if err != nil { n.stack.stats.MalformedRcvdPackets.Increment() return |