src/proto_ipv6_hop_by_hop.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 Hop-By-Hop Header described in RFC2460
   7  */
   8
   9 #ifndef PROTO_IPV6_HOP_BY_HOP_H
  10 #define PROTO_IPV6_HOP_BY_HOP_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 hop_by_hophdr {
  21         uint8_t h_next_header;
  22         uint8_t hdr_len;
  23 } __packed;
  24
  25 static inline void dissect_opt_hop (struct pkt_buff *pkt, size_t *opt_len)
  26 {
  27         /* Have to been upgraded.
  28          * http://tools.ietf.org/html/rfc2460#section-4.2
  29          * Look also for proto_ipv6_dest_opts.h, it needs
  30          * dissect_opt(), too.
  31          */
  32         if (*opt_len)
  33                 tprintf(", Option(s) recognized ");
  34
  35         /* If adding dissector reduce opt_len for each using of pkt_pull
  36          * to the same size.
  37          */
  38 }
  39
  40 static inline void hop_by_hop(struct pkt_buff *pkt)
  41 {
  42         uint16_t hdr_ext_len;
  43         size_t opt_len;
  44         struct hop_by_hophdr *hop_ops;
  45
  46         hop_ops = (struct hop_by_hophdr *) pkt_pull(pkt, sizeof(*hop_ops));
  47
  48         /* Total Header Length in Bytes */
  49         hdr_ext_len = (hop_ops->hdr_len + 1) * 8;
  50         /* Options length in Bytes */
  51         opt_len = hdr_ext_len - sizeof(*hop_ops);
  52         if (hop_ops == NULL || opt_len > pkt_len(pkt))
  53                 return;
  54
  55         tprintf("\t [ Hop-by-Hop Options ");
  56         tprintf("NextHdr (%u), ", hop_ops->h_next_header);
  57         tprintf("HdrExtLen (%u, %u Bytes)", hop_ops->hdr_len,
  58                 hdr_ext_len);
  59
  60         dissect_opt_hop(pkt, &opt_len);
  61
  62         tprintf(" ]\n");
  63
  64         pkt_pull(pkt, opt_len);
  65         pkt_set_proto(pkt, &eth_lay3, hop_ops->h_next_header);
  66 }
  67
  68 static inline void hop_by_hop_less(struct pkt_buff *pkt)
  69 {
  70         uint16_t hdr_ext_len;
  71         size_t opt_len;
  72         struct hop_by_hophdr *hop_ops;
  73
  74         hop_ops = (struct hop_by_hophdr *) pkt_pull(pkt, sizeof(*hop_ops));
  75
  76         /* Total Header Length in Bytes */
  77         hdr_ext_len = (hop_ops->hdr_len + 1) * 8;
  78         /* Options length in Bytes */
  79         opt_len = hdr_ext_len - sizeof(*hop_ops);
  80         if (hop_ops == NULL || opt_len > pkt_len(pkt))
  81                 return;
  82
  83         tprintf(" Hop Ops");
  84
  85         pkt_pull(pkt, opt_len);
  86         pkt_set_proto(pkt, &eth_lay3, hop_ops->h_next_header);
  87 }
  88
  89 struct protocol ipv6_hop_by_hop_ops = {
  90         .key = 0x0,
  91         .print_full = hop_by_hop,
  92         .print_less = hop_by_hop_less,
  93 };
  94
  95 #endif /* PROTO_IPV6_HOP_BY_HOP_H */