Hi, all,
I am trying to capture a GRE tunneled packet and get rid off the GRE header
to retrieve the encapsulated packet.
The code is quite simple, I basically grabs the GRE tunneled packet and
build a new one from its payload. The problem I have here is the MetaData
of the packet1 channel is completely empty, even though the decoded layers
look just fine.
Can anybody help me to figure out where I made the mistake?
Thanks,
Chun
--------- code snip ------
packetSource := gopacket.NewPacketSource(handle, handle.LinkType())
for packet := range packetSource.Packets() {
if packet.Layer(layers.LayerTypeGRE) == nil {
fmt.Println("not gre kets")
//if this is not a GRE tunneled pkt, then this is
not what we are looking for
continue
}
fmt.Println("find a GRE tunnedl pkt")
packet1 :=
gopacket.NewPacket(packet.Layer(layers.LayerTypeGRE).LayerPayload(),
layers.LinkTypeEthernet, gopacket.Default)
// shouldn't a channel type of Packet being returned here, with Metadata()
method implemented?
// Process packet here
fmt.Println(packet1)
fmt.Println("capture lenght:",
packet1.Metadata().CaptureLength, "timestamp:",
packet1.Metadata().Timestamp, "capture info:",
packet1.Metadata().CaptureInfo)
w.WritePacket(packet1.Metadata().CaptureInfo,
packet1.Data())
packetCount++
------ console print -------- test.pcap is completely empty since the
capture length from the metadata is 0
find a GRE tunnedl pkt
PACKET: 64 bytes
- Layer 1 (14 bytes) = Ethernet {Contents=[..14..] Payload=[..50..]
SrcMAC=00:04:96:6d:49:00 DstMAC=00:50:56:88:4e:2d EthernetType=Dot1Q
Length=0}
- Layer 2 (04 bytes) = Dot1Q {Contents=[0, 69, 8, 0] Payload=[..46..]
Priority=0 DropEligible=false VLANIdentifier=69 Type=IPv4}
- Layer 3 (20 bytes) = IPv4 {Contents=[..20..] Payload=[..20..]
Version=4 IHL=5 TOS=16 Length=40 Id=25729 Flags=DF FragOffset=0 TTL=59
Protocol=TCP Checksum=6231 SrcIP=10.6.105.21 DstIP=10.68.69.137 Options=[]
Padding=[]}
- Layer 4 (20 bytes) = TCP {Contents=[..20..] Payload=[] SrcPort=50507
DstPort=22(ssh) Seq=3986061698 Ack=2511277766 DataOffset=5 FIN=false
SYN=false RST=false PSH=false ACK=true URG=false ECE=false CWR=false
NS=false Window=8039 Checksum=64660 Urgent=0 Options=[] Padding=[]}
capture lenght: 0 timestamp: 0001-01-01 00:00:00 +0000 UTC capture info:
{0001-01-01 00:00:00 +0000 UTC 0 0 0}
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
