diff options
Diffstat (limited to 'pkg/tcpip/link/sniffer')
| -rw-r--r-- | pkg/tcpip/link/sniffer/BUILD | 4 | ||||
| -rw-r--r-- | pkg/tcpip/link/sniffer/sniffer.go | 118 |
2 files changed, 90 insertions, 32 deletions
diff --git a/pkg/tcpip/link/sniffer/BUILD b/pkg/tcpip/link/sniffer/BUILD index 1756114e6..d6ae0368a 100644 --- a/pkg/tcpip/link/sniffer/BUILD +++ b/pkg/tcpip/link/sniffer/BUILD @@ -9,9 +9,7 @@ go_library( "sniffer.go", ], importpath = "gvisor.dev/gvisor/pkg/tcpip/link/sniffer", - visibility = [ - "//visibility:public", - ], + visibility = ["//visibility:public"], deps = [ "//pkg/log", "//pkg/tcpip", diff --git a/pkg/tcpip/link/sniffer/sniffer.go b/pkg/tcpip/link/sniffer/sniffer.go index e401dce44..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 @@ -116,19 +123,19 @@ func NewWithFile(lower stack.LinkEndpoint, file *os.File, snapLen uint32) (stack // DeliverNetworkPacket implements the stack.NetworkDispatcher interface. It is // called by the link-layer endpoint being wrapped when a packet arrives, and // logs the packet before forwarding to the actual dispatcher. -func (e *endpoint) DeliverNetworkPacket(linkEP stack.LinkEndpoint, remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, vv buffer.VectorisedView) { +func (e *endpoint) DeliverNetworkPacket(linkEP stack.LinkEndpoint, remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) { if atomic.LoadUint32(&LogPackets) == 1 && e.file == nil { - logPacket("recv", protocol, vv.First(), nil) + logPacket("recv", protocol, pkt.Data.First(), nil) } if e.file != nil && atomic.LoadUint32(&LogPacketsToFile) == 1 { - vs := vv.Views() - length := vv.Size() + vs := pkt.Data.Views() + length := 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(vv.Size()))); err != nil { + if err := binary.Write(buf, binary.BigEndian, newPCAPPacketHeader(uint32(length), uint32(pkt.Data.Size()))); err != nil { panic(err) } for _, v := range vs { @@ -147,7 +154,7 @@ func (e *endpoint) DeliverNetworkPacket(linkEP stack.LinkEndpoint, remote, local panic(err) } } - e.dispatcher.DeliverNetworkPacket(e, remote, local, protocol, vv) + e.dispatcher.DeliverNetworkPacket(e, remote, local, protocol, pkt) } // Attach implements the stack.LinkEndpoint interface. It saves the dispatcher @@ -193,22 +200,19 @@ func (e *endpoint) GSOMaxSize() uint32 { return 0 } -// 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 { +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 { @@ -218,26 +222,75 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, hdr buffer.Prepen panic(err) } length -= len(hdrBuf) - if length > 0 { - for _, v := range payload.Views() { - if len(v) > length { - v = v[:length] - } - n, err := buf.Write(v) - if err != nil { - panic(err) - } - length -= n - if length == 0 { - break - } - } + logVectorisedView(pkt.Data, length, buf) + if _, err := e.file.Write(buf.Bytes()); err != nil { + panic(err) } + } +} + +// 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, 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, 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, pkts, protocol) +} + +// WriteRawPacket implements stack.LinkEndpoint.WriteRawPacket. +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 := 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(vv.Size()))); err != nil { + panic(err) + } + logVectorisedView(vv, length, buf) if _, err := e.file.Write(buf.Bytes()); err != nil { panic(err) } } - return e.lower.WritePacket(r, gso, hdr, payload, protocol) + return e.lower.WriteRawPacket(vv) +} + +func logVectorisedView(vv buffer.VectorisedView, length int, buf *bytes.Buffer) { + if length <= 0 { + return + } + for _, v := range vv.Views() { + if len(v) > length { + v = v[:length] + } + n, err := buf.Write(v) + if err != nil { + panic(err) + } + length -= n + if length == 0 { + return + } + } } // Wait implements stack.LinkEndpoint.Wait. @@ -287,6 +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) |