diff options
Diffstat (limited to 'pkg/tcpip/network/ipv4/icmp.go')
| -rw-r--r-- | pkg/tcpip/network/ipv4/icmp.go | 104 |
1 files changed, 75 insertions, 29 deletions
diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go index 50b363dc4..b5659a36b 100644 --- a/pkg/tcpip/network/ipv4/icmp.go +++ b/pkg/tcpip/network/ipv4/icmp.go @@ -24,8 +24,12 @@ import ( // the original packet that caused the ICMP one to be sent. This information is // used to find out which transport endpoint must be notified about the ICMP // packet. -func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, vv buffer.VectorisedView) { - h := header.IPv4(vv.First()) +func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt *stack.PacketBuffer) { + h, ok := pkt.Data.PullUp(header.IPv4MinimumSize) + if !ok { + return + } + hdr := header.IPv4(h) // We don't use IsValid() here because ICMP only requires that the IP // header plus 8 bytes of the transport header be included. So it's @@ -33,13 +37,14 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, vv buffer. // false. // // Drop packet if it doesn't have the basic IPv4 header or if the - // original source address doesn't match the endpoint's address. - if len(h) < header.IPv4MinimumSize || h.SourceAddress() != e.id.LocalAddress { + // original source address doesn't match an address we own. + src := hdr.SourceAddress() + if e.stack.CheckLocalAddress(e.NICID(), ProtocolNumber, src) == 0 { return } - hlen := int(h.HeaderLength()) - if vv.Size() < hlen || h.FragmentOffset() != 0 { + hlen := int(hdr.HeaderLength()) + if pkt.Data.Size() < hlen || hdr.FragmentOffset() != 0 { // We won't be able to handle this if it doesn't contain the // full IPv4 header, or if it's a fragment not at offset 0 // (because it won't have the transport header). @@ -47,16 +52,19 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, vv buffer. } // Skip the ip header, then deliver control message. - vv.TrimFront(hlen) - p := h.TransportProtocol() - e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, h.DestinationAddress(), ProtocolNumber, p, typ, extra, vv) + pkt.Data.TrimFront(hlen) + p := hdr.TransportProtocol() + e.dispatcher.DeliverTransportControlPacket(src, hdr.DestinationAddress(), ProtocolNumber, p, typ, extra, pkt) } -func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.VectorisedView) { +func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer) { stats := r.Stats() received := stats.ICMP.V4PacketsReceived - v := vv.First() - if len(v) < header.ICMPv4MinimumSize { + // TODO(gvisor.dev/issue/170): ICMP packets don't have their + // TransportHeader fields set. See icmp/protocol.go:protocol.Parse for a + // full explanation. + v, ok := pkt.Data.PullUp(header.ICMPv4MinimumSize) + if !ok { received.Invalid.Increment() return } @@ -73,29 +81,64 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.V // checksum. We'll have to reset this before we hand the packet // off. h.SetChecksum(0) - gotChecksum := ^header.ChecksumVV(vv, 0 /* initial */) + gotChecksum := ^header.ChecksumVV(pkt.Data, 0 /* initial */) if gotChecksum != wantChecksum { // It's possible that a raw socket expects to receive this. h.SetChecksum(wantChecksum) - e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, netHeader, vv) + e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, pkt) received.Invalid.Increment() return } + // Make a copy of data before pkt gets sent to raw socket. + // DeliverTransportPacket will take ownership of pkt. + replyData := pkt.Data.Clone(nil) + replyData.TrimFront(header.ICMPv4MinimumSize) + // It's possible that a raw socket expects to receive this. h.SetChecksum(wantChecksum) - e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, netHeader, vv) - - vv := vv.Clone(nil) - vv.TrimFront(header.ICMPv4MinimumSize) - hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv4MinimumSize) - pkt := header.ICMPv4(hdr.Prepend(header.ICMPv4MinimumSize)) - copy(pkt, h) - pkt.SetType(header.ICMPv4EchoReply) - pkt.SetChecksum(0) - pkt.SetChecksum(^header.Checksum(pkt, header.ChecksumVV(vv, 0))) + e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, pkt) + + remoteLinkAddr := r.RemoteLinkAddress + + // As per RFC 1122 section 3.2.1.3, when a host sends any datagram, the IP + // source address MUST be one of its own IP addresses (but not a broadcast + // or multicast address). + localAddr := r.LocalAddress + if r.IsInboundBroadcast() || header.IsV4MulticastAddress(r.LocalAddress) { + localAddr = "" + } + + r, err := r.Stack().FindRoute(e.NICID(), localAddr, r.RemoteAddress, ProtocolNumber, false /* multicastLoop */) + if err != nil { + // If we cannot find a route to the destination, silently drop the packet. + return + } + defer r.Release() + + // Use the remote link address from the incoming packet. + r.ResolveWith(remoteLinkAddr) + + // Prepare a reply packet. + icmpHdr := make(header.ICMPv4, header.ICMPv4MinimumSize) + copy(icmpHdr, h) + icmpHdr.SetType(header.ICMPv4EchoReply) + icmpHdr.SetChecksum(0) + icmpHdr.SetChecksum(^header.Checksum(icmpHdr, header.ChecksumVV(replyData, 0))) + dataVV := buffer.View(icmpHdr).ToVectorisedView() + dataVV.Append(replyData) + replyPkt := stack.NewPacketBuffer(stack.PacketBufferOptions{ + ReserveHeaderBytes: int(r.MaxHeaderLength()), + Data: dataVV, + }) + + // Send out the reply packet. sent := stats.ICMP.V4PacketsSent - if err := r.WritePacket(nil /* gso */, hdr, vv, stack.NetworkHeaderParams{Protocol: header.ICMPv4ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}); err != nil { + if err := r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{ + Protocol: header.ICMPv4ProtocolNumber, + TTL: r.DefaultTTL(), + TOS: stack.DefaultTOS, + }, replyPkt); err != nil { sent.Dropped.Increment() return } @@ -104,19 +147,22 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.V case header.ICMPv4EchoReply: received.EchoReply.Increment() - e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, netHeader, vv) + e.dispatcher.DeliverTransportPacket(r, header.ICMPv4ProtocolNumber, pkt) case header.ICMPv4DstUnreachable: received.DstUnreachable.Increment() - vv.TrimFront(header.ICMPv4MinimumSize) + pkt.Data.TrimFront(header.ICMPv4MinimumSize) switch h.Code() { + case header.ICMPv4HostUnreachable: + e.handleControl(stack.ControlNoRoute, 0, pkt) + case header.ICMPv4PortUnreachable: - e.handleControl(stack.ControlPortUnreachable, 0, vv) + e.handleControl(stack.ControlPortUnreachable, 0, pkt) case header.ICMPv4FragmentationNeeded: mtu := uint32(h.MTU()) - e.handleControl(stack.ControlPacketTooBig, calculateMTU(mtu), vv) + e.handleControl(stack.ControlPacketTooBig, calculateMTU(mtu), pkt) } case header.ICMPv4SrcQuench: |