calculate TCP payload slice sizes for Ethernet II packets less than 6…

…4 octets (#326) * remove unused bCLRF var. * calculate TCP payload slice sizes for Ethernet II packets less than 64 octets * simplify slicing off padding for Ethernet link packets less than 61 octets in length. * Make IPv4 header stripping comments more accurate.
buger · Jul 6, 2016 · c128d46 · c128d46
1 parent 1ed8691
commit c128d46
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Showing 2 changed files with 6 additions and 2 deletions.
diff --git a/raw_socket_listener/listener.go b/raw_socket_listener/listener.go
@@ -433,7 +433,12 @@ func (t *Listener) readPcap() {
 
 					srcIP = data[12:16]
 					dstIP = data[16:20]
-					data = data[ihl*4:]
+					// Stripping off the IP header
+					if len(packet.Data()) <= 60 && decoder == layers.LinkTypeEthernet { // Small Ethernet packets have padding
+						data = data[ihl * 4: int(binary.BigEndian.Uint16(data[2:4]))]
+					} else {
+						data = data[ihl * 4:]
+					}
 				} else {
 					// Truncated IP info
 					if len(data) < 40 {

diff --git a/raw_socket_listener/tcp_message.go b/raw_socket_listener/tcp_message.go
@@ -171,7 +171,6 @@ func (t *TCPMessage) checkSeqIntegrity() {
 	t.seqMissing = false
 }
 
-var bCLRF = []byte("\r\n")
 var bEmptyLine = []byte("\r\n\r\n")
 var bChunkEnd = []byte("0\r\n\r\n")