external/bsd/tcpdump/dist/print-sll.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21
  22 #include <sys/cdefs.h>
  23 #ifndef lint
  24 __RCSID("$NetBSD: print-sll.c,v 1.6 2015/03/31 21:59:35 christos Exp $");
  25 #endif
  26
  27 #define NETDISSECT_REWORKED
  28 #ifdef HAVE_CONFIG_H
  29 #include "config.h"
  30 #endif
  31
  32 #include <tcpdump-stdinc.h>
  33
  34 #include "interface.h"
  35 #include "addrtoname.h"
  36 #include "ethertype.h"
  37 #include "extract.h"
  38
  39 #include "ether.h"
  40
  41 /*
  42  * For captures on Linux cooked sockets, we construct a fake header
  43  * that includes:
  44  *
  45  *      a 2-byte "packet type" which is one of:
  46  *
  47  *              LINUX_SLL_HOST          packet was sent to us
  48  *              LINUX_SLL_BROADCAST     packet was broadcast
  49  *              LINUX_SLL_MULTICAST     packet was multicast
  50  *              LINUX_SLL_OTHERHOST     packet was sent to somebody else
  51  *              LINUX_SLL_OUTGOING      packet was sent *by* us;
  52  *
  53  *      a 2-byte Ethernet protocol field;
  54  *
  55  *      a 2-byte link-layer type;
  56  *
  57  *      a 2-byte link-layer address length;
  58  *
  59  *      an 8-byte source link-layer address, whose actual length is
  60  *      specified by the previous value.
  61  *
  62  * All fields except for the link-layer address are in network byte order.
  63  *
  64  * DO NOT change the layout of this structure, or change any of the
  65  * LINUX_SLL_ values below.  If you must change the link-layer header
  66  * for a "cooked" Linux capture, introduce a new DLT_ type (ask
  67  * "tcpdump-workers@lists.tcpdump.org" for one, so that you don't give it
  68  * a value that collides with a value already being used), and use the
  69  * new header in captures of that type, so that programs that can
  70  * handle DLT_LINUX_SLL captures will continue to handle them correctly
  71  * without any change, and so that capture files with different headers
  72  * can be told apart and programs that read them can dissect the
  73  * packets in them.
  74  *
  75  * This structure, and the #defines below, must be the same in the
  76  * libpcap and tcpdump versions of "sll.h".
  77  */
  78
  79 /*
  80  * A DLT_LINUX_SLL fake link-layer header.
  81  */
  82 #define SLL_HDR_LEN     16              /* total header length */
  83 #define SLL_ADDRLEN     8               /* length of address field */
  84
  85 struct sll_header {
  86         uint16_t        sll_pkttype;    /* packet type */
  87         uint16_t        sll_hatype;     /* link-layer address type */
  88         uint16_t        sll_halen;      /* link-layer address length */
  89         uint8_t         sll_addr[SLL_ADDRLEN];  /* link-layer address */
  90         uint16_t        sll_protocol;   /* protocol */
  91 };
  92
  93 /*
  94  * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the
  95  * PACKET_ values on Linux, but are defined here so that they're
  96  * available even on systems other than Linux, and so that they
  97  * don't change even if the PACKET_ values change.
  98  */
  99 #define LINUX_SLL_HOST          0
 100 #define LINUX_SLL_BROADCAST     1
 101 #define LINUX_SLL_MULTICAST     2
 102 #define LINUX_SLL_OTHERHOST     3
 103 #define LINUX_SLL_OUTGOING      4
 104
 105 /*
 106  * The LINUX_SLL_ values for "sll_protocol"; these correspond to the
 107  * ETH_P_ values on Linux, but are defined here so that they're
 108  * available even on systems other than Linux.  We assume, for now,
 109  * that the ETH_P_ values won't change in Linux; if they do, then:
 110  *
 111  *      if we don't translate them in "pcap-linux.c", capture files
 112  *      won't necessarily be readable if captured on a system that
 113  *      defines ETH_P_ values that don't match these values;
 114  *
 115  *      if we do translate them in "pcap-linux.c", that makes life
 116  *      unpleasant for the BPF code generator, as the values you test
 117  *      for in the kernel aren't the values that you test for when
 118  *      reading a capture file, so the fixup code run on BPF programs
 119  *      handed to the kernel ends up having to do more work.
 120  *
 121  * Add other values here as necessary, for handling packet types that
 122  * might show up on non-Ethernet, non-802.x networks.  (Not all the ones
 123  * in the Linux "if_ether.h" will, I suspect, actually show up in
 124  * captures.)
 125  */
 126 #define LINUX_SLL_P_802_3       0x0001  /* Novell 802.3 frames without 802.2 LLC header */
 127 #define LINUX_SLL_P_802_2       0x0004  /* 802.2 frames (not D/I/X Ethernet) */
 128
 129 static const struct tok sll_pkttype_values[] = {
 130     { LINUX_SLL_HOST, "In" },
 131     { LINUX_SLL_BROADCAST, "B" },
 132     { LINUX_SLL_MULTICAST, "M" },
 133     { LINUX_SLL_OTHERHOST, "P" },
 134     { LINUX_SLL_OUTGOING, "Out" },
 135     { 0, NULL}
 136 };
 137
 138 static inline void
 139 sll_print(netdissect_options *ndo, register const struct sll_header *sllp, u_int length)
 140 {
 141         u_short ether_type;
 142
 143         ND_PRINT((ndo, "%3s ",tok2str(sll_pkttype_values,"?",EXTRACT_16BITS(&sllp->sll_pkttype))));
 144
 145         /*
 146          * XXX - check the link-layer address type value?
 147          * For now, we just assume 6 means Ethernet.
 148          * XXX - print others as strings of hex?
 149          */
 150         if (EXTRACT_16BITS(&sllp->sll_halen) == 6)
 151                 ND_PRINT((ndo, "%s ", etheraddr_string(ndo, sllp->sll_addr)));
 152
 153         if (!ndo->ndo_qflag) {
 154                 ether_type = EXTRACT_16BITS(&sllp->sll_protocol);
 155
 156                 if (ether_type <= ETHERMTU) {
 157                         /*
 158                          * Not an Ethernet type; what type is it?
 159                          */
 160                         switch (ether_type) {
 161
 162                         case LINUX_SLL_P_802_3:
 163                                 /*
 164                                  * Ethernet_802.3 IPX frame.
 165                                  */
 166                                 ND_PRINT((ndo, "802.3"));
 167                                 break;
 168
 169                         case LINUX_SLL_P_802_2:
 170                                 /*
 171                                  * 802.2.
 172                                  */
 173                                 ND_PRINT((ndo, "802.2"));
 174                                 break;
 175
 176                         default:
 177                                 /*
 178                                  * What is it?
 179                                  */
 180                                 ND_PRINT((ndo, "ethertype Unknown (0x%04x)",
 181                                     ether_type));
 182                                 break;
 183                         }
 184                 } else {
 185                         ND_PRINT((ndo, "ethertype %s (0x%04x)",
 186                             tok2str(ethertype_values, "Unknown", ether_type),
 187                             ether_type));
 188                 }
 189                 ND_PRINT((ndo, ", length %u: ", length));
 190         }
 191 }
 192
 193 /*
 194  * This is the top level routine of the printer.  'p' points to the
 195  * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp,
 196  * 'h->len' is the length of the packet off the wire, and 'h->caplen'
 197  * is the number of bytes actually captured.
 198  */
 199 u_int
 200 sll_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
 201 {
 202         u_int caplen = h->caplen;
 203         u_int length = h->len;
 204         register const struct sll_header *sllp;
 205         u_short ether_type;
 206         u_short extracted_ethertype;
 207
 208         if (caplen < SLL_HDR_LEN) {
 209                 /*
 210                  * XXX - this "can't happen" because "pcap-linux.c" always
 211                  * adds this many bytes of header to every packet in a
 212                  * cooked socket capture.
 213                  */
 214                 ND_PRINT((ndo, "[|sll]"));
 215                 return (caplen);
 216         }
 217
 218         sllp = (const struct sll_header *)p;
 219
 220         if (ndo->ndo_eflag)
 221                 sll_print(ndo, sllp, length);
 222
 223         /*
 224          * Go past the cooked-mode header.
 225          */
 226         length -= SLL_HDR_LEN;
 227         caplen -= SLL_HDR_LEN;
 228         p += SLL_HDR_LEN;
 229
 230         ether_type = EXTRACT_16BITS(&sllp->sll_protocol);
 231
 232 recurse:
 233         /*
 234          * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 235          * packet type?
 236          */
 237         if (ether_type <= ETHERMTU) {
 238                 /*
 239                  * Yes - what type is it?
 240                  */
 241                 switch (ether_type) {
 242
 243                 case LINUX_SLL_P_802_3:
 244                         /*
 245                          * Ethernet_802.3 IPX frame.
 246                          */
 247                         ipx_print(ndo, p, length);
 248                         break;
 249
 250                 case LINUX_SLL_P_802_2:
 251                         /*
 252                          * 802.2.
 253                          * Try to print the LLC-layer header & higher layers.
 254                          */
 255                         if (llc_print(ndo, p, length, caplen, NULL, NULL,
 256                             &extracted_ethertype) == 0)
 257                                 goto unknown;   /* unknown LLC type */
 258                         break;
 259
 260                 default:
 261                         extracted_ethertype = 0;
 262                         /*FALLTHROUGH*/
 263
 264                 unknown:
 265                         /* ether_type not known, print raw packet */
 266                         if (!ndo->ndo_eflag)
 267                                 sll_print(ndo, sllp, length + SLL_HDR_LEN);
 268                         if (extracted_ethertype) {
 269                                 ND_PRINT((ndo, "(LLC %s) ",
 270                                etherproto_string(htons(extracted_ethertype))));
 271                         }
 272                         if (!ndo->ndo_suppress_default_print)
 273                                 ND_DEFAULTPRINT(p, caplen);
 274                         break;
 275                 }
 276         } else if (ether_type == ETHERTYPE_8021Q) {
 277                 /*
 278                  * Print VLAN information, and then go back and process
 279                  * the enclosed type field.
 280                  */
 281                 if (caplen < 4 || length < 4) {
 282                         ND_PRINT((ndo, "[|vlan]"));
 283                         return (SLL_HDR_LEN);
 284                 }
 285                 if (ndo->ndo_eflag) {
 286                         uint16_t tag = EXTRACT_16BITS(p);
 287
 288                         ND_PRINT((ndo, "%s, ", ieee8021q_tci_string(tag)));
 289                 }
 290
 291                 ether_type = EXTRACT_16BITS(p + 2);
 292                 if (ether_type <= ETHERMTU)
 293                         ether_type = LINUX_SLL_P_802_2;
 294                 if (!ndo->ndo_qflag) {
 295                         ND_PRINT((ndo, "ethertype %s, ",
 296                             tok2str(ethertype_values, "Unknown", ether_type)));
 297                 }
 298                 p += 4;
 299                 length -= 4;
 300                 caplen -= 4;
 301                 goto recurse;
 302         } else {
 303                 if (ethertype_print(ndo, ether_type, p, length, caplen) == 0) {
 304                         /* ether_type not known, print raw packet */
 305                         if (!ndo->ndo_eflag)
 306                                 sll_print(ndo, sllp, length + SLL_HDR_LEN);
 307                         if (!ndo->ndo_suppress_default_print)
 308                                 ND_DEFAULTPRINT(p, caplen);
 309                 }
 310         }
 311
 312         return (SLL_HDR_LEN);
 313 }