src/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 "protos.h"
  16 #include "dissector_eth.h"
  17 #include "built_in.h"
  18 #include "pkt_buff.h"
  19
  20 #define ROUTING_HEADER_TYPE_0   0x00
  21
  22 struct routinghdr {
  23         uint8_t h_next_header;
  24         uint8_t h_hdr_ext_len;
  25         uint8_t h_routing_type;
  26         uint8_t h_segments_left;
  27 } __packed;
  28
  29 struct routinghdr_0 {
  30         uint32_t reserved;
  31         uint32_t addresses[0];
  32 } __packed;
  33
  34 static void dissect_routinghdr_type_0(struct pkt_buff *pkt,
  35                                       ssize_t *data_len, int less)
  36 {
  37         uint8_t num_addr;
  38         char address[INET6_ADDRSTRLEN];
  39         struct in6_addr *addr;
  40         struct routinghdr_0 *routing_0;
  41
  42         routing_0 = (struct routinghdr_0 *) pkt_pull(pkt, sizeof(*routing_0));
  43         *data_len -= sizeof(*routing_0);
  44         if (routing_0 == NULL || *data_len > pkt_len(pkt) || *data_len < 0)
  45                 return;
  46
  47         if (less) {
  48                 tprintf("Addresses (%u)", *data_len / sizeof(struct in6_addr));
  49                 return;
  50         }
  51
  52         tprintf("Res (0x%x)", routing_0->reserved);
  53
  54         num_addr = *data_len / sizeof(*addr);
  55
  56         while (num_addr--) {
  57                 addr = (struct in6_addr *) pkt_pull(pkt, sizeof(*addr));
  58                 *data_len -= sizeof(*addr);
  59                 if (addr == NULL || *data_len > pkt_len(pkt) || *data_len < 0)
  60                         return;
  61
  62                 tprintf("\n\t   Address: %s",
  63                         inet_ntop(AF_INET6, addr, address,
  64                                   sizeof(address)));
  65         }
  66 }
  67
  68 static inline void dissect_routinghdr_type_0_norm(struct pkt_buff *pkt,
  69                                                   ssize_t *data_len)
  70 {
  71         dissect_routinghdr_type_0(pkt, data_len, 0);
  72 }
  73
  74 static inline void dissect_routinghdr_type_0_less(struct pkt_buff *pkt,
  75                                                   ssize_t *data_len)
  76 {
  77         dissect_routinghdr_type_0(pkt, data_len, 1);
  78 }
  79
  80 static void routing(struct pkt_buff *pkt)
  81 {
  82         uint16_t hdr_ext_len;
  83         ssize_t data_len;
  84         struct routinghdr *routing;
  85
  86         routing = (struct routinghdr *) pkt_pull(pkt, sizeof(*routing));
  87         if (routing == NULL)
  88                 return;
  89
  90         /* Total Header Length in Bytes */
  91         hdr_ext_len = (routing->h_hdr_ext_len + 1) * 8;
  92         /* Data length in Bytes */
  93         data_len = hdr_ext_len - sizeof(*routing);
  94
  95         tprintf("\t [ Routing ");
  96         tprintf("NextHdr (%u), ", routing->h_next_header);
  97         if (data_len > pkt_len(pkt) || data_len < 0){
  98                 tprintf("HdrExtLen (%u, %u Bytes %s), ", routing->h_hdr_ext_len,
  99                       hdr_ext_len, colorize_start_full(black, red)
 100                       "invalid" colorize_end());
 101                       return;
 102         }
 103         tprintf("HdrExtLen (%u, %u Bytes), ", routing->h_hdr_ext_len,
 104                 hdr_ext_len);
 105         tprintf("Type (%u), ", routing->h_routing_type);
 106         tprintf("Left (%u), ", routing->h_segments_left);
 107
 108         switch (routing->h_routing_type) {
 109         case ROUTING_HEADER_TYPE_0:
 110                 dissect_routinghdr_type_0_norm(pkt, &data_len);
 111                 break;
 112         default:
 113                 tprintf("Type %u is unknown", routing->h_routing_type);
 114         }
 115
 116         tprintf(" ]\n");
 117
 118         if (data_len > pkt_len(pkt) || data_len < 0)
 119                 return;
 120
 121         pkt_pull(pkt, data_len);
 122         pkt_set_proto(pkt, &eth_lay3, routing->h_next_header);
 123 }
 124
 125 static void routing_less(struct pkt_buff *pkt)
 126 {
 127         uint16_t hdr_ext_len;
 128         ssize_t data_len;
 129         struct routinghdr *routing;
 130
 131         routing = (struct routinghdr *) pkt_pull(pkt, sizeof(*routing));
 132         if (routing == NULL)
 133                 return;
 134
 135         /* Total Header Length in Bytes */
 136         hdr_ext_len = (routing->h_hdr_ext_len + 1) * 8;
 137         /* Data length in Bytes */
 138         data_len = hdr_ext_len - sizeof(*routing);
 139         if (data_len > pkt_len(pkt) || data_len < 0)
 140                 return;
 141
 142         tprintf(" Routing ");
 143
 144         switch (routing->h_routing_type) {
 145         case ROUTING_HEADER_TYPE_0:
 146                 dissect_routinghdr_type_0_less(pkt, &data_len);
 147                 break;
 148         default:
 149                 tprintf("Type %u is unknown", routing->h_routing_type);
 150         }
 151
 152         if (data_len > pkt_len(pkt) || data_len < 0)
 153                 return;
 154
 155         pkt_pull(pkt, data_len);
 156         pkt_set_proto(pkt, &eth_lay3, routing->h_next_header);
 157 }
 158
 159 struct protocol ipv6_routing_ops = {
 160         .key = 0x2B,
 161         .print_full = routing,
 162         .print_less = routing_less,
 163 };
 164
 165 EXPORT_SYMBOL(ipv6_routing_ops);