The Tcpdump Group git mirrors - tcpdump/blob - print-nflog.c

   1 /*
   2  * Copyright (c) 2013, Petar Alilovic,
   3  * Faculty of Electrical Engineering and Computing, University of Zagreb
   4  * All rights reserved
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are met:
   8  *
   9  * * Redistributions of source code must retain the above copyright notice,
  10  *       this list of conditions and the following disclaimer.
  11  * * Redistributions in binary form must reproduce the above copyright
  12  *       notice, this list of conditions and the following disclaimer in the
  13  *       documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
  16  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  18  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
  19  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  20  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  21  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  22  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  25  * DAMAGE.
  26  */
  27
  28 #ifdef HAVE_CONFIG_H
  29 #include "config.h"
  30 #endif
  31
  32 #include <tcpdump-stdinc.h>
  33
  34 #include <stdio.h>
  35 #include <pcap.h>
  36
  37 #include "netdissect.h"
  38 #include "interface.h"
  39
  40 /*
  41  * Structure of an NFLOG header and TLV parts, as described at
  42  * http://www.tcpdump.org/linktypes/LINKTYPE_NFLOG.html
  43  */
  44 typedef struct nflog_hdr {
  45         u_int8_t        nflog_family;           /* adress family */
  46         u_int8_t        nflog_version;          /* version */
  47         u_int16_t       nflog_rid;                      /* resource ID */
  48 } nflog_hdr_t;
  49
  50 typedef struct nflog_tlv {
  51         u_int16_t       tlv_length;             /* tlv length */
  52         u_int16_t       tlv_type;               /* tlv type */
  53         void*           tlv_value;              /* tlv value */
  54 } nflog_tlv_t;
  55
  56 #ifdef DLT_NFLOG
  57
  58 #define NFULA_PAYLOAD 9
  59
  60 static const struct tok nflog_values[] = {
  61         { AF_INET,              "IPv4" },
  62         { AF_INET6,             "IPv6" },
  63         { 0,                            NULL }
  64 };
  65
  66 static inline void
  67 nflog_hdr_print(struct netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
  68 {
  69         ND_PRINT((ndo, "version %d, resource ID %d", hdr->nflog_version, ntohs(hdr->nflog_rid)));
  70
  71         if (!ndo->ndo_qflag) {
  72                 ND_PRINT((ndo,", family %s (%d)",
  73                                                   tok2str(nflog_values, "Unknown",
  74                                                                   hdr->nflog_family),
  75                                                   hdr->nflog_family));
  76                 } else {
  77                 ND_PRINT((ndo,", %s",
  78                                                   tok2str(nflog_values,
  79                                                                   "Unknown NFLOG (0x%02x)",
  80                                                                   hdr->nflog_family)));
  81                 }
  82
  83         ND_PRINT((ndo, ", length %u: ", length));
  84 }
  85
  86 u_int
  87 nflog_if_print(struct netdissect_options *ndo,
  88                            const struct pcap_pkthdr *h, const u_char *p)
  89 {
  90         const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
  91         const nflog_tlv_t *tlv;
  92         u_int16_t size;
  93         u_int16_t h_size = sizeof(nflog_hdr_t);
  94         u_int caplen = h->caplen;
  95         u_int length = h->len;
  96
  97         if (caplen < (int) sizeof(nflog_hdr_t) || length < (int) sizeof(nflog_hdr_t)) {
  98                 ND_PRINT((ndo, "[|nflog]"));
  99                 return h_size;
 100         }
 101
 102         if (!(hdr->nflog_version) == 0) {
 103                 ND_PRINT((ndo, "version %u (unknown)", hdr->nflog_version));
 104                 return h_size;
 105         }
 106
 107         if (ndo->ndo_eflag)
 108                 nflog_hdr_print(ndo, hdr, length);
 109
 110         length -= sizeof(nflog_hdr_t);
 111         caplen -= sizeof(nflog_hdr_t);
 112         p += sizeof(nflog_hdr_t);
 113
 114         do {
 115                 tlv = (const nflog_tlv_t *) p;
 116                 size = tlv->tlv_length;
 117
 118                 if (size % 4 != 0)
 119                         size += 4 - size % 4;
 120
 121                 h_size = h_size + size;
 122
 123                 /* wrong size of the packet */
 124                 if (size > length || size == 0)
 125                         return h_size;
 126
 127                 p += size;
 128                 length = length - size;
 129                 caplen = caplen - size;
 130
 131         } while (tlv->tlv_type != NFULA_PAYLOAD);
 132
 133         /* dont skip payload just tlv length and type */
 134         p = p - size + 4;
 135         length += size - 4;
 136         caplen += size - 4;
 137         h_size -= length;
 138
 139         switch (hdr->nflog_family) {
 140
 141         case AF_INET:
 142                         ip_print(ndo, p, length);
 143                 break;
 144
 145 #ifdef INET6
 146         case AF_INET6:
 147                 ip6_print(ndo, p, length);
 148                 break;
 149 #endif /*INET6*/
 150
 151         default:
 152                 if (!ndo->ndo_eflag)
 153                         nflog_hdr_print(ndo, hdr,
 154                                 length + sizeof(nflog_hdr_t));
 155
 156                 if (!ndo->ndo_suppress_default_print)
 157                         ndo->ndo_default_print(ndo, p, caplen);
 158                 break;
 159         }
 160
 161         return h_size;
 162 }
 163
 164 #endif /* DLT_NFLOG */