@@ -44,17 +44,19 @@ var LogPackets atomicbitops.Uint32 = atomicbitops.FromUint32(1)
4444// sniffer was created for this flag to have effect.
4545var LogPacketsToPCAP atomicbitops.Uint32 = atomicbitops .FromUint32 (1 )
4646
47+ // Endpoint is used to sniff and log network traffic.
48+ //
4749// +stateify savable
48- type endpoint struct {
50+ type Endpoint struct {
4951 nested.Endpoint
5052 writer io.Writer
5153 maxPCAPLen uint32
5254 logPrefix string
5355}
5456
55- var _ stack.GSOEndpoint = (* endpoint )(nil )
56- var _ stack.LinkEndpoint = (* endpoint )(nil )
57- var _ stack.NetworkDispatcher = (* endpoint )(nil )
57+ var _ stack.GSOEndpoint = (* Endpoint )(nil )
58+ var _ stack.LinkEndpoint = (* Endpoint )(nil )
59+ var _ stack.NetworkDispatcher = (* Endpoint )(nil )
5860
5961// A Direction indicates whether the packing is being sent or received.
6062type Direction int
@@ -66,9 +68,20 @@ const (
6668 DirectionRecv
6769)
6870
71+ func (dr Direction ) String () string {
72+ switch dr {
73+ case DirectionSend :
74+ return "send"
75+ case DirectionRecv :
76+ return "recv"
77+ default :
78+ panic (fmt .Sprintf ("invalid Direction %d" , dr ))
79+ }
80+ }
81+
6982// New creates a new sniffer link-layer endpoint. It wraps around another
7083// endpoint and logs packets and they traverse the endpoint.
71- func New (lower stack.LinkEndpoint ) stack. LinkEndpoint {
84+ func New (lower stack.LinkEndpoint ) * Endpoint {
7285 return NewWithPrefix (lower , "" )
7386}
7487
@@ -79,8 +92,8 @@ func New(lower stack.LinkEndpoint) stack.LinkEndpoint {
7992// logPrefix is prepended to the log line without any separators.
8093// E.g. logPrefix = "NIC:en0/" will produce log lines like
8194// "NIC:en0/send udp [...]".
82- func NewWithPrefix (lower stack.LinkEndpoint , logPrefix string ) stack. LinkEndpoint {
83- sniffer := & endpoint {logPrefix : logPrefix }
95+ func NewWithPrefix (lower stack.LinkEndpoint , logPrefix string ) * Endpoint {
96+ sniffer := & Endpoint {logPrefix : logPrefix }
8497 sniffer .Endpoint .Init (lower , sniffer )
8598 return sniffer
8699}
@@ -119,11 +132,11 @@ func writePCAPHeader(w io.Writer, maxLen uint32) error {
119132// snapLen is the maximum amount of a packet to be saved. Packets with a length
120133// less than or equal to snapLen will be saved in their entirety. Longer
121134// packets will be truncated to snapLen.
122- func NewWithWriter (lower stack.LinkEndpoint , writer io.Writer , snapLen uint32 ) (stack. LinkEndpoint , error ) {
135+ func NewWithWriter (lower stack.LinkEndpoint , writer io.Writer , snapLen uint32 ) (* Endpoint , error ) {
123136 if err := writePCAPHeader (writer , snapLen ); err != nil {
124137 return nil , err
125138 }
126- sniffer := & endpoint {
139+ sniffer := & Endpoint {
127140 writer : writer ,
128141 maxPCAPLen : snapLen ,
129142 }
@@ -134,22 +147,28 @@ func NewWithWriter(lower stack.LinkEndpoint, writer io.Writer, snapLen uint32) (
134147// DeliverNetworkPacket implements the stack.NetworkDispatcher interface. It is
135148// called by the link-layer endpoint being wrapped when a packet arrives, and
136149// logs the packet before forwarding to the actual dispatcher.
137- func (e * endpoint ) DeliverNetworkPacket (protocol tcpip.NetworkProtocolNumber , pkt * stack.PacketBuffer ) {
138- e .dumpPacket (DirectionRecv , protocol , pkt )
150+ func (e * Endpoint ) DeliverNetworkPacket (protocol tcpip.NetworkProtocolNumber , pkt * stack.PacketBuffer ) {
151+ e .DumpPacket (DirectionRecv , protocol , pkt , nil )
139152 e .Endpoint .DeliverNetworkPacket (protocol , pkt )
140153}
141154
142- func (e * endpoint ) dumpPacket (dir Direction , protocol tcpip.NetworkProtocolNumber , pkt * stack.PacketBuffer ) {
155+ // DumpPacket logs a packet, depending on configuration, to stderr and/or a
156+ // pcap file. ts is an optional timestamp for the packet.
157+ func (e * Endpoint ) DumpPacket (dir Direction , protocol tcpip.NetworkProtocolNumber , pkt * stack.PacketBuffer , ts * time.Time ) {
143158 writer := e .writer
144159 if LogPackets .Load () == 1 {
145160 LogPacket (e .logPrefix , dir , protocol , pkt )
146161 }
147162 if writer != nil && LogPacketsToPCAP .Load () == 1 {
148163 packet := pcapPacket {
149- timestamp : time .Now (),
150164 packet : pkt ,
151165 maxCaptureLen : int (e .maxPCAPLen ),
152166 }
167+ if ts == nil {
168+ packet .timestamp = time .Now ()
169+ } else {
170+ packet .timestamp = * ts
171+ }
153172 b , err := packet .MarshalBinary ()
154173 if err != nil {
155174 panic (err )
@@ -163,9 +182,9 @@ func (e *endpoint) dumpPacket(dir Direction, protocol tcpip.NetworkProtocolNumbe
163182// WritePackets implements the stack.LinkEndpoint interface. It is called by
164183// higher-level protocols to write packets; it just logs the packet and
165184// forwards the request to the lower endpoint.
166- func (e * endpoint ) WritePackets (pkts stack.PacketBufferList ) (int , tcpip.Error ) {
185+ func (e * Endpoint ) WritePackets (pkts stack.PacketBufferList ) (int , tcpip.Error ) {
167186 for _ , pkt := range pkts .AsSlice () {
168- e .dumpPacket (DirectionSend , pkt .NetworkProtocolNumber , pkt )
187+ e .DumpPacket (DirectionSend , pkt .NetworkProtocolNumber , pkt , nil )
169188 }
170189 return e .Endpoint .WritePackets (pkts )
171190}
@@ -181,16 +200,6 @@ func LogPacket(prefix string, dir Direction, protocol tcpip.NetworkProtocolNumbe
181200 var fragmentOffset uint16
182201 var moreFragments bool
183202
184- var directionPrefix string
185- switch dir {
186- case DirectionSend :
187- directionPrefix = "send"
188- case DirectionRecv :
189- directionPrefix = "recv"
190- default :
191- panic (fmt .Sprintf ("unrecognized direction: %d" , dir ))
192- }
193-
194203 clone := trimmedClone (pkt )
195204 defer clone .DecRef ()
196205 switch protocol {
@@ -232,14 +241,14 @@ func LogPacket(prefix string, dir Direction, protocol tcpip.NetworkProtocolNumbe
232241 log .Infof (
233242 "%s%s arp %s (%s) -> %s (%s) valid:%t" ,
234243 prefix ,
235- directionPrefix ,
244+ dir ,
236245 tcpip .AddrFromSlice (arp .ProtocolAddressSender ()), tcpip .LinkAddress (arp .HardwareAddressSender ()),
237246 tcpip .AddrFromSlice (arp .ProtocolAddressTarget ()), tcpip .LinkAddress (arp .HardwareAddressTarget ()),
238247 arp .IsValid (),
239248 )
240249 return
241250 default :
242- log .Infof ("%s%s unknown network protocol: %d" , prefix , directionPrefix , protocol )
251+ log .Infof ("%s%s unknown network protocol: %d" , prefix , dir , protocol )
243252 return
244253 }
245254
@@ -283,7 +292,7 @@ func LogPacket(prefix string, dir Direction, protocol tcpip.NetworkProtocolNumbe
283292 icmpType = "info reply"
284293 }
285294 }
286- log .Infof ("%s%s %s %s -> %s %s len:%d id:%04x code:%d" , prefix , directionPrefix , transName , src , dst , icmpType , size , id , icmp .Code ())
295+ log .Infof ("%s%s %s %s -> %s %s len:%d id:%04x code:%d" , prefix , dir , transName , src , dst , icmpType , size , id , icmp .Code ())
287296 return
288297
289298 case header .ICMPv6ProtocolNumber :
@@ -318,7 +327,7 @@ func LogPacket(prefix string, dir Direction, protocol tcpip.NetworkProtocolNumbe
318327 case header .ICMPv6RedirectMsg :
319328 icmpType = "redirect message"
320329 }
321- log .Infof ("%s%s %s %s -> %s %s len:%d id:%04x code:%d" , prefix , directionPrefix , transName , src , dst , icmpType , size , id , icmp .Code ())
330+ log .Infof ("%s%s %s %s -> %s %s len:%d id:%04x code:%d" , prefix , dir , transName , src , dst , icmpType , size , id , icmp .Code ())
322331 return
323332
324333 case header .UDPProtocolNumber :
@@ -359,24 +368,24 @@ func LogPacket(prefix string, dir Direction, protocol tcpip.NetworkProtocolNumbe
359368
360369 // Initialize the TCP flags.
361370 flags := tcp .Flags ()
362- details = fmt .Sprintf ("flags: %s seqnum: %d ack: %d win: %d xsum:0x%x" , flags , tcp .SequenceNumber (), tcp .AckNumber (), tcp .WindowSize (), tcp .Checksum ())
371+ details = fmt .Sprintf ("flags:%s seqnum:%d ack:%d win:%d xsum:0x%x" , flags , tcp .SequenceNumber (), tcp .AckNumber (), tcp .WindowSize (), tcp .Checksum ())
363372 if flags & header .TCPFlagSyn != 0 {
364- details += fmt .Sprintf (" options: %+v" , header .ParseSynOptions (tcp .Options (), flags & header .TCPFlagAck != 0 ))
373+ details += fmt .Sprintf (" options:%+v" , header .ParseSynOptions (tcp .Options (), flags & header .TCPFlagAck != 0 ))
365374 } else {
366- details += fmt .Sprintf (" options: %+v" , tcp .ParsedOptions ())
375+ details += fmt .Sprintf (" options:%+v" , tcp .ParsedOptions ())
367376 }
368377 }
369378
370379 default :
371- log .Infof ("%s%s %s -> %s unknown transport protocol: %d" , prefix , directionPrefix , src , dst , transProto )
380+ log .Infof ("%s%s %s -> %s unknown transport protocol: %d" , prefix , dir , src , dst , transProto )
372381 return
373382 }
374383
375384 if pkt .GSOOptions .Type != stack .GSONone {
376- details += fmt .Sprintf (" gso: %#v" , pkt .GSOOptions )
385+ details += fmt .Sprintf (" gso:%#v" , pkt .GSOOptions )
377386 }
378387
379- log .Infof ("%s%s %s %s:%d -> %s:%d len:%d id:%04x %s" , prefix , directionPrefix , transName , src , srcPort , dst , dstPort , size , id , details )
388+ log .Infof ("%s%s %s %s:%d -> %s:%d len:%d id:0x %04x %s" , prefix , dir , transName , src , srcPort , dst , dstPort , size , id , details )
380389}
381390
382391// trimmedClone clones the packet buffer to not modify the original. It trims
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