proto_mpls_unicast.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2012 Markus Amend <markus@netsniff-ng.org>, Deutsche Flugsicherung GmbH
   4  * Subject to the GPL, version 2.
   5  *
   6  * http://tools.ietf.org/html/rfc3032
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdint.h>
  11 #include <netinet/in.h>    /* for ntohs() */
  12 #include <errno.h>
  13
  14 #include "proto.h"
  15 #include "dissector_eth.h"
  16 #include "built_in.h"
  17 #include "pkt_buff.h"
  18
  19 struct mpls_uchdr {
  20         uint32_t mpls_uc_hdr;
  21 } __packed;
  22
  23 static int mpls_uc_next_proto(struct pkt_buff *pkt)
  24 {
  25         uint8_t proto;
  26         uint16_t key = 0;
  27
  28         if (pkt_len(pkt))
  29                 proto = *(pkt->data);
  30         else
  31                 return -EIO;
  32
  33         /* FIXME: Right now only test for IP Version field */
  34         switch (proto >> 4) {
  35         case 4:
  36                 key = 0x0800; /* IPv4*/
  37                 break;
  38         case 6:
  39                 key = 0x86DD; /* IPv6*/
  40                 break;
  41         default:
  42                 /* Nothing detected ... */
  43                 return -ENOENT;
  44         }
  45
  46         return key;
  47 }
  48
  49 static void mpls_uc_full(struct pkt_buff *pkt)
  50 {
  51         int next;
  52         uint32_t mpls_uc_data;
  53         struct mpls_uchdr *mpls_uc;
  54         uint8_t s = 0;
  55
  56         do {
  57                 mpls_uc = (struct mpls_uchdr *) pkt_pull(pkt, sizeof(*mpls_uc));
  58                 if (mpls_uc == NULL)
  59                         return;
  60
  61                 mpls_uc_data = ntohl(mpls_uc->mpls_uc_hdr);
  62                 s = (mpls_uc_data >> 8) & 0x1;
  63
  64                 tprintf(" [ MPLS ");
  65                 tprintf("Label (%u), ", mpls_uc_data >> 12);
  66                 tprintf("Exp (%u), ", (mpls_uc_data >> 9) & 0x7);
  67                 tprintf("S (%u), ", s);
  68                 tprintf("TTL (%u)", (mpls_uc_data & 0xFF));
  69                 tprintf(" ]\n");
  70         } while (!s);
  71
  72         next = mpls_uc_next_proto(pkt);
  73         if (next < 0)
  74                 return;
  75
  76         pkt_set_dissector(pkt, &eth_lay2, (uint16_t) next);
  77 }
  78
  79 static void mpls_uc_less(struct pkt_buff *pkt)
  80 {
  81         int next;
  82         uint32_t mpls_uc_data;
  83         struct mpls_uchdr *mpls_uc;
  84         uint8_t s = 0;
  85
  86         do {
  87                 mpls_uc = (struct mpls_uchdr *) pkt_pull(pkt, sizeof(*mpls_uc));
  88                 if (mpls_uc == NULL)
  89                         return;
  90
  91                 mpls_uc_data = ntohl(mpls_uc->mpls_uc_hdr);
  92                 s = (mpls_uc_data >> 8) & 0x1;
  93
  94                 tprintf(" MPLS/%u", mpls_uc_data >> 12);
  95         } while (!s);
  96
  97         next = mpls_uc_next_proto(pkt);
  98         if (next < 0)
  99                 return;
 100
 101         pkt_set_dissector(pkt, &eth_lay2, (uint16_t) next);
 102 }
 103
 104 struct protocol mpls_uc_ops = {
 105         .key = 0x8847,
 106         .print_full = mpls_uc_full,
 107         .print_less = mpls_uc_less,
 108 };