proto_ipv6_routing.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  * IPv6 Routing Header described in RFC2460
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdint.h>
  11 #include <netinet/in.h>    /* for ntohs() and "struct in6_addr" */
  12 #include <arpa/inet.h>     /* for inet_ntop() */
  13
  14 #include "proto.h"
  15 #include "dissector_eth.h"
  16 #include "built_in.h"
  17 #include "pkt_buff.h"
  18
  19 #define ROUTING_HEADER_TYPE_0   0x00
  20
  21 struct routinghdr {
  22         uint8_t h_next_header;
  23         uint8_t h_hdr_ext_len;
  24         uint8_t h_routing_type;
  25         uint8_t h_segments_left;
  26 } __packed;
  27
  28 struct routinghdr_0 {
  29         uint32_t reserved;
  30         uint32_t addresses[0];
  31 } __packed;
  32
  33 static void dissect_routinghdr_type_0(struct pkt_buff *pkt,
  34                                       ssize_t *data_len, int less)
  35 {
  36         uint8_t num_addr;
  37         char address[INET6_ADDRSTRLEN];
  38         struct in6_addr *addr;
  39         struct routinghdr_0 *routing_0;
  40
  41         routing_0 = (struct routinghdr_0 *) pkt_pull(pkt, sizeof(*routing_0));
  42         *data_len -= sizeof(*routing_0);
  43         if (routing_0 == NULL || *data_len > pkt_len(pkt) || *data_len < 0)
  44                 return;
  45
  46         if (less) {
  47                 tprintf("Addresses (%zu)", *data_len / sizeof(struct in6_addr));
  48                 return;
  49         }
  50
  51         tprintf("Res (0x%x)", routing_0->reserved);
  52
  53         num_addr = *data_len / sizeof(*addr);
  54
  55         while (num_addr--) {
  56                 addr = (struct in6_addr *) pkt_pull(pkt, sizeof(*addr));
  57                 *data_len -= sizeof(*addr);
  58                 if (addr == NULL || *data_len > pkt_len(pkt) || *data_len < 0)
  59                         return;
  60
  61                 tprintf("\n\t   Address: %s",
  62                         inet_ntop(AF_INET6, addr, address,
  63                                   sizeof(address)));
  64         }
  65 }
  66
  67 static inline void dissect_routinghdr_type_0_norm(struct pkt_buff *pkt,
  68                                                   ssize_t *data_len)
  69 {
  70         dissect_routinghdr_type_0(pkt, data_len, 0);
  71 }
  72
  73 static inline void dissect_routinghdr_type_0_less(struct pkt_buff *pkt,
  74                                                   ssize_t *data_len)
  75 {
  76         dissect_routinghdr_type_0(pkt, data_len, 1);
  77 }
  78
  79 static void routing(struct pkt_buff *pkt)
  80 {
  81         uint16_t hdr_ext_len;
  82         ssize_t data_len;
  83         struct routinghdr *routing;
  84
  85         routing = (struct routinghdr *) pkt_pull(pkt, sizeof(*routing));
  86         if (routing == NULL)
  87                 return;
  88
  89         /* Total Header Length in Bytes */
  90         hdr_ext_len = (routing->h_hdr_ext_len + 1) * 8;
  91         /* Data length in Bytes */
  92         data_len = hdr_ext_len - sizeof(*routing);
  93
  94         tprintf("\t [ Routing ");
  95         tprintf("NextHdr (%u), ", routing->h_next_header);
  96         if (data_len > pkt_len(pkt) || data_len < 0){
  97                 tprintf("HdrExtLen (%u, %u Bytes %s), ", routing->h_hdr_ext_len,
  98                       hdr_ext_len, colorize_start_full(black, red)
  99                       "invalid" colorize_end());
 100                       return;
 101         }
 102         tprintf("HdrExtLen (%u, %u Bytes), ", routing->h_hdr_ext_len,
 103                 hdr_ext_len);
 104         tprintf("Type (%u), ", routing->h_routing_type);
 105         tprintf("Left (%u), ", routing->h_segments_left);
 106
 107         switch (routing->h_routing_type) {
 108         case ROUTING_HEADER_TYPE_0:
 109                 dissect_routinghdr_type_0_norm(pkt, &data_len);
 110                 break;
 111         default:
 112                 tprintf("Type %u is unknown", routing->h_routing_type);
 113         }
 114
 115         tprintf(" ]\n");
 116
 117         if (data_len > pkt_len(pkt) || data_len < 0)
 118                 return;
 119
 120         pkt_pull(pkt, data_len);
 121         pkt_set_dissector(pkt, &eth_lay3, routing->h_next_header);
 122 }
 123
 124 static void routing_less(struct pkt_buff *pkt)
 125 {
 126         uint16_t hdr_ext_len;
 127         ssize_t data_len;
 128         struct routinghdr *routing;
 129
 130         routing = (struct routinghdr *) pkt_pull(pkt, sizeof(*routing));
 131         if (routing == NULL)
 132                 return;
 133
 134         /* Total Header Length in Bytes */
 135         hdr_ext_len = (routing->h_hdr_ext_len + 1) * 8;
 136         /* Data length in Bytes */
 137         data_len = hdr_ext_len - sizeof(*routing);
 138         if (data_len > pkt_len(pkt) || data_len < 0)
 139                 return;
 140
 141         tprintf(" Routing ");
 142
 143         switch (routing->h_routing_type) {
 144         case ROUTING_HEADER_TYPE_0:
 145                 dissect_routinghdr_type_0_less(pkt, &data_len);
 146                 break;
 147         default:
 148                 tprintf("Type %u is unknown", routing->h_routing_type);
 149         }
 150
 151         if (data_len > pkt_len(pkt) || data_len < 0)
 152                 return;
 153
 154         pkt_pull(pkt, data_len);
 155         pkt_set_dissector(pkt, &eth_lay3, routing->h_next_header);
 156 }
 157
 158 struct protocol ipv6_routing_ops = {
 159         .key = 0x2B,
 160         .print_full = routing,
 161         .print_less = routing_less,
 162 };