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 /* \summary: DLT_NFLOG printer */
  29
  30 #ifdef HAVE_CONFIG_H
  31 #include <config.h>
  32 #endif
  33
  34 #include "netdissect-stdinc.h"
  35
  36 #define ND_LONGJMP_FROM_TCHECK
  37 #include "netdissect.h"
  38 #include "extract.h"
  39
  40 #ifdef DLT_NFLOG
  41
  42 /*
  43  * Structure of an NFLOG header and TLV parts, as described at
  44  * https://www.tcpdump.org/linktypes/LINKTYPE_NFLOG.html
  45  *
  46  * The NFLOG header is big-endian.
  47  *
  48  * The TLV length and type are in host byte order.  The value is either
  49  * big-endian or is an array of bytes in some externally-specified byte
  50  * order (text string, link-layer address, link-layer header, packet
  51  * data, etc.).
  52  */
  53 typedef struct nflog_hdr {
  54         nd_uint8_t      nflog_family;           /* address family */
  55         nd_uint8_t      nflog_version;          /* version */
  56         nd_uint16_t     nflog_rid;              /* resource ID */
  57 } nflog_hdr_t;
  58
  59 #define NFLOG_HDR_LEN sizeof(nflog_hdr_t)
  60
  61 typedef struct nflog_tlv {
  62         nd_uint16_t     tlv_length;             /* tlv length */
  63         nd_uint16_t     tlv_type;               /* tlv type */
  64         /* value follows this */
  65 } nflog_tlv_t;
  66
  67 #define NFLOG_TLV_LEN sizeof(nflog_tlv_t)
  68
  69 typedef struct nflog_packet_hdr {
  70         nd_uint16_t     hw_protocol;    /* hw protocol */
  71         nd_uint8_t      hook;           /* netfilter hook */
  72         nd_byte         pad[1];         /* padding to 32 bits */
  73 } nflog_packet_hdr_t;
  74
  75 typedef struct nflog_hwaddr {
  76         nd_uint16_t     hw_addrlen;     /* address length */
  77         nd_byte         pad[2];         /* padding to 32-bit boundary */
  78         nd_byte         hw_addr[8];     /* address, up to 8 bytes */
  79 } nflog_hwaddr_t;
  80
  81 typedef struct nflog_timestamp {
  82         nd_uint64_t     sec;
  83         nd_uint64_t     usec;
  84 } nflog_timestamp_t;
  85
  86 /*
  87  * TLV types.
  88  */
  89 #define NFULA_PACKET_HDR                1       /* nflog_packet_hdr_t */
  90 #define NFULA_MARK                      2       /* packet mark from skbuff */
  91 #define NFULA_TIMESTAMP                 3       /* nflog_timestamp_t for skbuff's time stamp */
  92 #define NFULA_IFINDEX_INDEV             4       /* ifindex of device on which packet received (possibly bridge group) */
  93 #define NFULA_IFINDEX_OUTDEV            5       /* ifindex of device on which packet transmitted (possibly bridge group) */
  94 #define NFULA_IFINDEX_PHYSINDEV         6       /* ifindex of physical device on which packet received (not bridge group) */
  95 #define NFULA_IFINDEX_PHYSOUTDEV        7       /* ifindex of physical device on which packet transmitted (not bridge group) */
  96 #define NFULA_HWADDR                    8       /* nflog_hwaddr_t for hardware address */
  97 #define NFULA_PAYLOAD                   9       /* packet payload */
  98 #define NFULA_PREFIX                    10      /* text string - null-terminated, count includes NUL */
  99 #define NFULA_UID                       11      /* UID owning socket on which packet was sent/received */
 100 #define NFULA_SEQ                       12      /* sequence number of packets on this NFLOG socket */
 101 #define NFULA_SEQ_GLOBAL                13      /* sequence number of packets on all NFLOG sockets */
 102 #define NFULA_GID                       14      /* GID owning socket on which packet was sent/received */
 103 #define NFULA_HWTYPE                    15      /* ARPHRD_ type of skbuff's device */
 104 #define NFULA_HWHEADER                  16      /* skbuff's MAC-layer header */
 105 #define NFULA_HWLEN                     17      /* length of skbuff's MAC-layer header */
 106
 107 /*
 108  * Define two constants specifically for the two AF code points from the
 109  * LINKTYPE_NFLOG specification above and use these constants instead of
 110  * AF_INET and AF_INET6.  This is the only way to dissect the "wire" encoding
 111  * correctly because some BSD systems define AF_INET6 differently from Linux
 112  * (see af.h) and Haiku defines both AF_INET and AF_INET6 differently from
 113  * Linux.
 114  */
 115 #define NFLOG_AF_INET   2
 116 #define NFLOG_AF_INET6 10
 117 static const struct tok nflog_values[] = {
 118         { NFLOG_AF_INET,        "IPv4" },
 119         { NFLOG_AF_INET6,       "IPv6" },
 120         { 0,                    NULL }
 121 };
 122
 123 static void
 124 nflog_hdr_print(netdissect_options *ndo, const nflog_hdr_t *hdr, u_int length)
 125 {
 126         ND_PRINT("version %u, resource ID %u",
 127             GET_U_1(hdr->nflog_version), GET_BE_U_2(hdr->nflog_rid));
 128
 129         if (!ndo->ndo_qflag) {
 130                 ND_PRINT(", family %s (%u)",
 131                          tok2str(nflog_values, "Unknown",
 132                                  GET_U_1(hdr->nflog_family)),
 133                          GET_U_1(hdr->nflog_family));
 134                 } else {
 135                 ND_PRINT(", %s",
 136                          tok2str(nflog_values,
 137                                  "Unknown NFLOG (0x%02x)",
 138                          GET_U_1(hdr->nflog_family)));
 139                 }
 140
 141         ND_PRINT(", length %u: ", length);
 142 }
 143
 144 void
 145 nflog_if_print(netdissect_options *ndo,
 146                const struct pcap_pkthdr *h, const u_char *p)
 147 {
 148         const nflog_hdr_t *hdr = (const nflog_hdr_t *)p;
 149         uint16_t size;
 150         uint16_t h_size = NFLOG_HDR_LEN;
 151         u_int caplen = h->caplen;
 152         u_int length = h->len;
 153
 154         ndo->ndo_protocol = "nflog";
 155         ND_ICHECK_ZU(length, <, NFLOG_HDR_LEN);
 156
 157         ND_TCHECK_SIZE(hdr);
 158         ndo->ndo_ll_hdr_len += NFLOG_HDR_LEN;
 159
 160         if (GET_U_1(hdr->nflog_version) != 0) {
 161                 ND_PRINT("version %u (unknown)", GET_U_1(hdr->nflog_version));
 162                 return;
 163         }
 164
 165         if (ndo->ndo_eflag)
 166                 nflog_hdr_print(ndo, hdr, length);
 167
 168         p += NFLOG_HDR_LEN;
 169         length -= NFLOG_HDR_LEN;
 170         caplen -= NFLOG_HDR_LEN;
 171
 172         while (length != 0) {
 173                 const nflog_tlv_t *tlv;
 174
 175                 ND_ICHECK_ZU(length, <, NFLOG_TLV_LEN);
 176                 tlv = (const nflog_tlv_t *) p;
 177                 /* Do we have enough data for the TLV header? */
 178                 ND_TCHECK_SIZE(tlv);
 179                 size = GET_HE_U_2(tlv->tlv_length);
 180                 if (size % 4 != 0)
 181                         size += 4 - size % 4;
 182
 183                 /* Is the TLV's length less than the minimum? */
 184                 ND_ICHECK_ZU(size, <, NFLOG_TLV_LEN);
 185                 ND_ICHECK_U(length, <, size);
 186
 187                 /* Do we have enough data for the full TLV? */
 188                 ND_TCHECK_LEN(tlv, size);
 189
 190                 if (GET_HE_U_2(tlv->tlv_type) == NFULA_PAYLOAD) {
 191                         /*
 192                          * This TLV's data is the packet payload.
 193                          * Skip past the TLV header, and break out
 194                          * of the loop so we print the packet data.
 195                          */
 196                         p += NFLOG_TLV_LEN;
 197                         h_size += NFLOG_TLV_LEN;
 198                         length -= NFLOG_TLV_LEN;
 199                         caplen -= NFLOG_TLV_LEN;
 200                         break;
 201                 }
 202
 203                 p += size;
 204                 h_size += size;
 205                 length -= size;
 206                 caplen -= size;
 207         }
 208
 209         switch (GET_U_1(hdr->nflog_family)) {
 210
 211         case NFLOG_AF_INET:
 212                 ip_print(ndo, p, length);
 213                 break;
 214
 215         case NFLOG_AF_INET6:
 216                 ip6_print(ndo, p, length);
 217                 break;
 218
 219         default:
 220                 if (!ndo->ndo_eflag)
 221                         nflog_hdr_print(ndo, hdr,
 222                                         length + NFLOG_HDR_LEN);
 223
 224                 if (!ndo->ndo_suppress_default_print)
 225                         ND_DEFAULTPRINT(p, caplen);
 226                 break;
 227         }
 228
 229         ndo->ndo_ll_hdr_len += h_size - NFLOG_HDR_LEN;
 230         return;
 231
 232 invalid:
 233         nd_print_invalid(ndo);
 234 }
 235
 236 #endif /* DLT_NFLOG */