proto_vlan.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2009, 2010 Daniel Borkmann.
   4  * Copyright 2010 Emmanuel Roullit.
   5  * Subject to the GPL, version 2.
   6  */
   7
   8 #include <stdio.h>
   9 #include <stdint.h>
  10 #include <netinet/in.h>    /* for ntohs() */
  11
  12 #include "proto.h"
  13 #include "protos.h"
  14 #include "dissector_eth.h"
  15 #include "pkt_buff.h"
  16
  17 struct vlanhdr {
  18         uint16_t h_vlan_TCI;
  19         uint16_t h_vlan_encapsulated_proto;
  20 } __attribute__((packed));
  21
  22 static void vlan(struct pkt_buff *pkt)
  23 {
  24         uint16_t tci;
  25         struct vlanhdr *vlan = (struct vlanhdr *) pkt_pull(pkt, sizeof(*vlan));
  26
  27         if (vlan == NULL)
  28                 return;
  29
  30         tci = ntohs(vlan->h_vlan_TCI);
  31
  32         tprintf(" [ VLAN ");
  33         tprintf("Prio (%d), ", (tci & 0xE000) >> 13);
  34         tprintf("CFI (%d), ", (tci & 0x1000) >> 12);
  35         tprintf("ID (%d), ", (tci & 0x0FFF));
  36         tprintf("Proto (0x%.4x)", ntohs(vlan->h_vlan_encapsulated_proto));
  37         tprintf(" ]\n");
  38
  39         pkt_set_proto(pkt, &eth_lay2, ntohs(vlan->h_vlan_encapsulated_proto));
  40 }
  41
  42 static void vlan_less(struct pkt_buff *pkt)
  43 {
  44         uint16_t tci;
  45         struct vlanhdr *vlan = (struct vlanhdr *) pkt_pull(pkt, sizeof(*vlan));
  46
  47         if (vlan == NULL)
  48                 return;
  49
  50         tci = ntohs(vlan->h_vlan_TCI);
  51
  52         tprintf(" VLAN%d", (tci & 0x0FFF));
  53
  54         pkt_set_proto(pkt, &eth_lay2, ntohs(vlan->h_vlan_encapsulated_proto));
  55 }
  56
  57 struct protocol vlan_ops = {
  58         .key = 0x8100,
  59         .print_full = vlan,
  60         .print_less = vlan_less,
  61 };