diff options
Diffstat (limited to 'pkg/tcpip/link/sniffer/sniffer.go')
| -rw-r--r-- | pkg/tcpip/link/sniffer/sniffer.go | 55 |
1 files changed, 36 insertions, 19 deletions
diff --git a/pkg/tcpip/link/sniffer/sniffer.go b/pkg/tcpip/link/sniffer/sniffer.go index d71a03cd2..3392b7edd 100644 --- a/pkg/tcpip/link/sniffer/sniffer.go +++ b/pkg/tcpip/link/sniffer/sniffer.go @@ -49,6 +49,13 @@ var LogPackets uint32 = 1 // LogPacketsToFile must be accessed atomically. var LogPacketsToFile uint32 = 1 +var transportProtocolMinSizes map[tcpip.TransportProtocolNumber]int = map[tcpip.TransportProtocolNumber]int{ + header.ICMPv4ProtocolNumber: header.IPv4MinimumSize, + header.ICMPv6ProtocolNumber: header.IPv6MinimumSize, + header.UDPProtocolNumber: header.UDPMinimumSize, + header.TCPProtocolNumber: header.TCPMinimumSize, +} + type endpoint struct { dispatcher stack.NetworkDispatcher lower stack.LinkEndpoint @@ -193,19 +200,19 @@ func (e *endpoint) GSOMaxSize() uint32 { return 0 } -func (e *endpoint) dumpPacket(gso *stack.GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) { +func (e *endpoint) dumpPacket(gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) { if atomic.LoadUint32(&LogPackets) == 1 && e.file == nil { - logPacket("send", protocol, hdr.View(), gso) + logPacket("send", protocol, pkt.Header.View(), gso) } if e.file != nil && atomic.LoadUint32(&LogPacketsToFile) == 1 { - hdrBuf := hdr.View() - length := len(hdrBuf) + payload.Size() + hdrBuf := pkt.Header.View() + length := len(hdrBuf) + pkt.Data.Size() if length > int(e.maxPCAPLen) { length = int(e.maxPCAPLen) } buf := bytes.NewBuffer(make([]byte, 0, pcapPacketHeaderLen+length)) - if err := binary.Write(buf, binary.BigEndian, newPCAPPacketHeader(uint32(length), uint32(len(hdrBuf)+payload.Size()))); err != nil { + if err := binary.Write(buf, binary.BigEndian, newPCAPPacketHeader(uint32(length), uint32(len(hdrBuf)+pkt.Data.Size()))); err != nil { panic(err) } if len(hdrBuf) > length { @@ -215,7 +222,7 @@ func (e *endpoint) dumpPacket(gso *stack.GSO, hdr buffer.Prependable, payload bu panic(err) } length -= len(hdrBuf) - logVectorisedView(payload, length, buf) + logVectorisedView(pkt.Data, length, buf) if _, err := e.file.Write(buf.Bytes()); err != nil { panic(err) } @@ -225,43 +232,46 @@ func (e *endpoint) dumpPacket(gso *stack.GSO, hdr buffer.Prependable, payload bu // WritePacket implements the stack.LinkEndpoint interface. It is called by // higher-level protocols to write packets; it just logs the packet and // forwards the request to the lower endpoint. -func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) *tcpip.Error { - e.dumpPacket(gso, hdr, payload, protocol) - return e.lower.WritePacket(r, gso, hdr, payload, protocol) +func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) *tcpip.Error { + e.dumpPacket(gso, protocol, pkt) + return e.lower.WritePacket(r, gso, protocol, pkt) } // WritePackets implements the stack.LinkEndpoint interface. It is called by // higher-level protocols to write packets; it just logs the packet and // forwards the request to the lower endpoint. -func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, hdrs []stack.PacketDescriptor, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) { - view := payload.ToView() - for _, d := range hdrs { - e.dumpPacket(gso, d.Hdr, buffer.NewVectorisedView(d.Size, []buffer.View{view[d.Off:][:d.Size]}), protocol) +func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts []tcpip.PacketBuffer, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) { + view := pkts[0].Data.ToView() + for _, pkt := range pkts { + e.dumpPacket(gso, protocol, tcpip.PacketBuffer{ + Header: pkt.Header, + Data: view[pkt.DataOffset:][:pkt.DataSize].ToVectorisedView(), + }) } - return e.lower.WritePackets(r, gso, hdrs, payload, protocol) + return e.lower.WritePackets(r, gso, pkts, protocol) } // WriteRawPacket implements stack.LinkEndpoint.WriteRawPacket. -func (e *endpoint) WriteRawPacket(packet buffer.VectorisedView) *tcpip.Error { +func (e *endpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error { if atomic.LoadUint32(&LogPackets) == 1 && e.file == nil { logPacket("send", 0, buffer.View("[raw packet, no header available]"), nil /* gso */) } if e.file != nil && atomic.LoadUint32(&LogPacketsToFile) == 1 { - length := packet.Size() + length := vv.Size() if length > int(e.maxPCAPLen) { length = int(e.maxPCAPLen) } buf := bytes.NewBuffer(make([]byte, 0, pcapPacketHeaderLen+length)) - if err := binary.Write(buf, binary.BigEndian, newPCAPPacketHeader(uint32(length), uint32(packet.Size()))); err != nil { + if err := binary.Write(buf, binary.BigEndian, newPCAPPacketHeader(uint32(length), uint32(vv.Size()))); err != nil { panic(err) } - logVectorisedView(packet, length, buf) + logVectorisedView(vv, length, buf) if _, err := e.file.Write(buf.Bytes()); err != nil { panic(err) } } - return e.lower.WriteRawPacket(packet) + return e.lower.WriteRawPacket(vv) } func logVectorisedView(vv buffer.VectorisedView, length int, buf *bytes.Buffer) { @@ -330,6 +340,13 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie return } + // We aren't guaranteed to have a transport header - it's possible for + // writes via raw endpoints to contain only network headers. + if minSize, ok := transportProtocolMinSizes[tcpip.TransportProtocolNumber(transProto)]; ok && len(b) < minSize { + log.Infof("%s %v -> %v transport protocol: %d, but no transport header found (possible raw packet)", prefix, src, dst, transProto) + return + } + // Figure out the transport layer info. transName := "unknown" srcPort := uint16(0) |