LINKTYPE_LINUX_LAPD

Packet structure

+---------------------------+
|         Packet type       |
|         (2 Octets)        |
+---------------------------+
|        ARPHRD_ type       |
|         (2 Octets)        |
+---------------------------+
| Link-layer address length |
|         (2 Octets)        |
+---------------------------+
|    Link-layer address     |
|         (8 Octets)        |
+---------------------------+
|        Protocol type      |
|         (2 Octets)        |
+---------------------------+
|           Payload         |
.                           .
.                           .
.                           .

Description

The packet type field is in network byte order (big-endian); it contains a value that is one of:

  • 0, if the packet was sent to us by somebody else;
  • 3, if the packet was sent to somebody else by somebody else;
  • 4, if the packet was sent by us.

For LAPD frames, the lower byte of the field is 0 for incoming packets and 4 for outgoing packets.

For log messages, if the lower byte of the field is 1, it's an indication that one or more messages have been missed and not captured.

The ARPHRD_ type field is unused.

The link-layer address length field is unused.

The link-layer address field is unused.

The protocol type field is in network byte order; it should contain the value 0x0030.