src/proto_ipv6_fragm.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 Fragmentation Header described in RFC2460
   7  */
   8
   9 #ifndef PROTO_IPV6_FRAGM_H
  10 #define PROTO_IPV6_FRAGM_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 fragmhdr {
  21         uint8_t h_fragm_next_header;
  22         uint8_t h_fragm_reserved;
  23         uint16_t h_fragm_off_res_M;
  24         uint32_t h_fragm_identification;
  25 } __packed;
  26
  27 static inline void fragm(uint8_t *packet, size_t len)
  28 {
  29         uint16_t off_res_M;
  30         struct fragmhdr *fragm = (struct fragmhdr *) packet;
  31
  32         if (len < sizeof(struct fragmhdr))
  33                 return;
  34
  35         off_res_M = ntohs(fragm->h_fragm_off_res_M);
  36
  37         tprintf("\t [ Fragment ");
  38         tprintf("NextHdr (%u), ", fragm->h_fragm_next_header);
  39         tprintf("Reserved (%u), ", fragm->h_fragm_reserved);
  40         tprintf("Offset (%u), ", off_res_M >> 3);
  41         tprintf("Res (%u), ", (off_res_M >> 1) & 0x3);
  42         tprintf("M flag (%u), ", off_res_M & 0x1);
  43         tprintf("Identification (%u) ", ntohl(fragm->h_fragm_identification));
  44         tprintf(" ]\n");
  45 }
  46
  47 static inline void fragm_less(uint8_t *packet, size_t len)
  48 {
  49         uint16_t off_res_M;
  50         struct fragmhdr *fragm = (struct fragmhdr *) packet;
  51
  52         if (len < sizeof(struct fragmhdr))
  53                 return;
  54
  55         off_res_M = ntohs(fragm->h_fragm_off_res_M);
  56
  57         tprintf(" FragmOffs %u", off_res_M >> 3);
  58 }
  59
  60 static inline void fragm_next(uint8_t *packet, size_t len,
  61                              struct hash_table **table,
  62                              unsigned int *key, size_t *off)
  63 {
  64         struct fragmhdr *fragm = (struct fragmhdr *) packet;
  65         if (len < sizeof(struct fragmhdr))
  66                 return;
  67         (*off) = sizeof(struct fragmhdr);
  68         (*key) = fragm->h_fragm_next_header;
  69         (*table) = &eth_lay3;
  70 }
  71
  72 struct protocol ipv6_fragm_ops = {
  73         .key = 0x2C,
  74         .print_full = fragm,
  75         .print_less = fragm_less,
  76         .proto_next = fragm_next,
  77 };
  78
  79 #endif /* PROTO_IPV6_FRAGM_H */