src/proto_ipv6_dest_opts.h

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2012 Markus Amend <markus@netsniff-ng.org>
   4  * Subject to the GPL, version 2.
   5  *
   6  * IPv6 Destination Options Header described in RFC2460
   7  */
   8
   9 #ifndef PROTO_IPV6_DEST_OPTS_H
  10 #define PROTO_IPV6_DEST_OPTS_H
  11
  12 #include <stdio.h>
  13 #include <stdint.h>
  14 #include <netinet/in.h>    /* for ntohs() */
  15
  16 #include "proto_struct.h"
  17 #include "dissector_eth.h"
  18 #include "built_in.h"
  19
  20 struct dest_optshdr {
  21         uint8_t h_next_header;
  22         uint8_t hdr_len;
  23 } __packed;
  24
  25
  26 static inline void dissect_opt_dest(struct pkt_buff *pkt, size_t *opt_len)
  27 {
  28         /* Have to been upgraded.
  29          * http://tools.ietf.org/html/rfc2460#section-4.2
  30          * Look also for proto_ipv6_hop_by_hop.h, it needs
  31          * dissect_opt(), too.
  32          */
  33         if (*opt_len)
  34                 tprintf(", Option(s) recognized ");
  35
  36         /* If adding dissector reduce opt_len for each using of pkt_pull
  37          * to the same size.
  38          */
  39 }
  40
  41 static inline void dest_opts(struct pkt_buff *pkt)
  42 {
  43         uint16_t hdr_ext_len;
  44         size_t opt_len;
  45         struct dest_optshdr *dest_ops;
  46
  47         dest_ops = (struct dest_optshdr *) pkt_pull(pkt, sizeof(*dest_ops));
  48
  49         /* Total Header Length in Bytes */
  50         hdr_ext_len = (dest_ops->hdr_len + 1) * 8;
  51         /* Options length in Bytes */
  52         opt_len = hdr_ext_len - sizeof(*dest_ops);
  53         if (dest_ops == NULL || opt_len > pkt_len(pkt))
  54                 return;
  55
  56         tprintf("\t [ Destination Options ");
  57         tprintf("NextHdr (%u), ", dest_ops->h_next_header);
  58         tprintf("HdrExtLen (%u, %u Bytes)", dest_ops->hdr_len,
  59                 hdr_ext_len);
  60
  61         dissect_opt_dest(pkt, &opt_len);
  62
  63         tprintf(" ]\n");
  64
  65         pkt_pull(pkt, opt_len);
  66         pkt_set_proto(pkt, &eth_lay3, dest_ops->h_next_header);
  67 }
  68
  69 static inline void dest_opts_less(struct pkt_buff *pkt)
  70 {
  71         uint16_t hdr_ext_len;
  72         size_t opt_len;
  73         struct dest_optshdr *dest_ops;
  74
  75         dest_ops = (struct dest_optshdr *) pkt_pull(pkt, sizeof(*dest_ops));
  76
  77         /* Total Header Length in Bytes */
  78         hdr_ext_len = (dest_ops->hdr_len + 1) * 8;
  79         /* Options length in Bytes */
  80         opt_len = hdr_ext_len - sizeof(*dest_ops);
  81         if (dest_ops == NULL || opt_len > pkt_len(pkt))
  82                 return;
  83
  84         tprintf(" Dest Ops");
  85
  86         pkt_pull(pkt, opt_len);
  87         pkt_set_proto(pkt, &eth_lay3, dest_ops->h_next_header);
  88 }
  89
  90 struct protocol ipv6_dest_opts_ops = {
  91         .key = 0x3C,
  92         .print_full = dest_opts,
  93         .print_less = dest_opts_less,
  94 };
  95
  96 #endif /* PROTO_IPV6_DEST_OPTS_H */