packet-sll.c

   1 /* packet-sll.c
   2  * Routines for disassembly of packets from Linux "cooked mode" captures
   3  *
   4  * $Id: packet-sll.c,v 1.8 2001/03/13 21:34:23 gram Exp $
   5  *
   6  * Ethereal - Network traffic analyzer
   7  * By Gerald Combs <gerald@zing.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version 2
  14  * of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #ifdef HAVE_SYS_TYPES_H
  31 # include <sys/types.h>
  32 #endif
  33
  34 #include <stdio.h>
  35 #include <string.h>
  36 #include <glib.h>
  37 #include "packet.h"
  38 #include "packet-ipx.h"
  39 #include "packet-llc.h"
  40 #include "resolv.h"
  41
  42 static int proto_sll = -1;
  43 static int hf_sll_pkttype = -1;
  44 static int hf_sll_hatype = -1;
  45 static int hf_sll_halen = -1;
  46 static int hf_sll_src_eth = -1;
  47 static int hf_sll_src_other = -1;
  48 static int hf_sll_ltype = -1;
  49 static int hf_sll_etype = -1;
  50 static int hf_sll_trailer = -1;
  51
  52 static gint ett_sll = -1;
  53
  54 /*
  55  * A DLT_LINUX_SLL fake link-layer header.
  56  */
  57 #define SLL_HEADER_SIZE 16              /* total header length */
  58 #define SLL_ADDRLEN     8               /* length of address field */
  59
  60 /*
  61  * The LINUX_SLL_ values for "sll_pkttype".
  62  */
  63 #define LINUX_SLL_HOST          0
  64 #define LINUX_SLL_BROADCAST     1
  65 #define LINUX_SLL_MULTICAST     2
  66 #define LINUX_SLL_OTHERHOST     3
  67 #define LINUX_SLL_OUTGOING      4
  68
  69 static const value_string packet_type_vals[] = {
  70         { LINUX_SLL_HOST,       "Unicast to us" },
  71         { LINUX_SLL_BROADCAST,  "Broadcast" },
  72         { LINUX_SLL_MULTICAST,  "Multicast" },
  73         { LINUX_SLL_OTHERHOST,  "Unicast to another host" },
  74         { LINUX_SLL_OUTGOING,   "Sent by us" },
  75         { 0,                    NULL }
  76 };
  77
  78 /*
  79  * The LINUX_SLL_ values for "sll_protocol".
  80  */
  81 #define LINUX_SLL_P_802_3       0x0001  /* Novell 802.3 frames without 802.2 LLC header */
  82 #define LINUX_SLL_P_802_2       0x0004  /* 802.2 frames (not D/I/X Ethernet) */
  83
  84 static const value_string ltype_vals[] = {
  85         { LINUX_SLL_P_802_3,    "Raw 802.3" },
  86         { LINUX_SLL_P_802_2,    "802.2 LLC" },
  87         { 0,                    NULL }
  88 };
  89
  90 static dissector_handle_t ipx_handle;
  91 static dissector_handle_t llc_handle;
  92
  93 void
  94 capture_sll(const u_char *pd, packet_counts *ld)
  95 {
  96         guint16 protocol;
  97
  98         if (!BYTES_ARE_IN_FRAME(0, SLL_HEADER_SIZE)) {
  99                 ld->other++;
 100                 return;
 101         }
 102         protocol = pntohs(&pd[14]);
 103         if (protocol <= 1536) { /* yes, 1536 - that's how Linux does it */
 104                 /*
 105                  * "proto" is *not* a length field, it's a Linux internal
 106                  * protocol type.
 107                  */
 108                 switch (protocol) {
 109
 110                 case LINUX_SLL_P_802_2:
 111                         /*
 112                          * 802.2 LLC.
 113                          */
 114                         capture_llc(pd, SLL_HEADER_SIZE, ld);
 115                         break;
 116
 117                 case LINUX_SLL_P_802_3:
 118                         /*
 119                          * Novell IPX inside 802.3 with no 802.2 LLC
 120                          * header.
 121                          */
 122                         capture_ipx(pd, SLL_HEADER_SIZE, ld);
 123                         break;
 124
 125                 default:
 126                         ld->other++;
 127                         break;
 128                 }
 129         } else
 130                 capture_ethertype(protocol, SLL_HEADER_SIZE, pd, ld);
 131 }
 132
 133 static void
 134 dissect_sll(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 135 {
 136         guint16 pkttype;
 137         guint16 protocol;
 138         guint16 hatype, halen;
 139         const guint8 *src;
 140         proto_item *ti;
 141         tvbuff_t *next_tvb;
 142         proto_tree *fh_tree = NULL;
 143
 144         if (check_col(pinfo->fd, COL_PROTOCOL))
 145                 col_set_str(pinfo->fd, COL_PROTOCOL, "SLL");
 146         if (check_col(pinfo->fd, COL_INFO))
 147                 col_clear(pinfo->fd, COL_INFO);
 148
 149         pkttype = tvb_get_ntohs(tvb, 0);
 150
 151         if (check_col(pinfo->fd, COL_INFO))
 152                 col_add_str(pinfo->fd, COL_INFO,
 153                     val_to_str(pkttype, packet_type_vals, "Unknown (%u)"));
 154
 155         if (tree) {
 156                 ti = proto_tree_add_protocol_format(tree, proto_sll, tvb, 0,
 157                     SLL_HEADER_SIZE, "Linux cooked capture");
 158                 fh_tree = proto_item_add_subtree(ti, ett_sll);
 159                 proto_tree_add_item(fh_tree, hf_sll_pkttype, tvb, 0, 2, FALSE);
 160         }
 161
 162         /*
 163          * XXX - check the link-layer address type value?
 164          * For now, we just assume 6 means Ethernet.
 165          */
 166         hatype = tvb_get_ntohs(tvb, 2);
 167         halen = tvb_get_ntohs(tvb, 4);
 168         if (tree) {
 169                 proto_tree_add_uint(fh_tree, hf_sll_hatype, tvb, 2, 2, hatype);
 170                 proto_tree_add_uint(fh_tree, hf_sll_halen, tvb, 4, 2, halen);
 171         }
 172         if (halen == 6) {
 173                 src = tvb_get_ptr(tvb, 6, 6);
 174                 SET_ADDRESS(&pinfo->dl_src, AT_ETHER, 6, src);
 175                 SET_ADDRESS(&pinfo->src, AT_ETHER, 6, src);
 176                 if (tree) {
 177                         proto_tree_add_ether(fh_tree, hf_sll_src_eth, tvb,
 178                             6, 6, src);
 179                 }
 180         } else {
 181                 if (tree) {
 182                         proto_tree_add_bytes(fh_tree, hf_sll_src_other, tvb,
 183                             6, halen, tvb_get_ptr(tvb, 6, halen));
 184                 }
 185         }
 186
 187         protocol = tvb_get_ntohs(tvb, 14);
 188         if (protocol <= 1536) { /* yes, 1536 - that's how Linux does it */
 189                 /*
 190                  * "proto" is *not* a length field, it's a Linux internal
 191                  * protocol type.
 192                  * We therefore cannot say how much of the packet will
 193                  * be trailer data.
 194                  * XXX - do the same thing we do for packets with Ethertypes?
 195                  */
 196                 proto_tree_add_uint(fh_tree, hf_sll_ltype, tvb, 14, 2,
 197                     protocol);
 198
 199                 next_tvb = tvb_new_subset(tvb, SLL_HEADER_SIZE, -1, -1);
 200                 switch (protocol) {
 201
 202                 case LINUX_SLL_P_802_2:
 203                         /*
 204                          * 802.2 LLC.
 205                          */
 206                         call_dissector(llc_handle, next_tvb, pinfo, tree);
 207                         break;
 208
 209                 case LINUX_SLL_P_802_3:
 210                         /*
 211                          * Novell IPX inside 802.3 with no 802.2 LLC
 212                          * header.
 213                          */
 214                         call_dissector(ipx_handle, next_tvb, pinfo, tree);
 215                         break;
 216
 217                 default:
 218                         dissect_data(next_tvb, 0, pinfo, tree);
 219                         break;
 220                 }
 221         } else {
 222                 ethertype(protocol, tvb, SLL_HEADER_SIZE, pinfo, tree,
 223                     fh_tree, hf_sll_etype, hf_sll_trailer);
 224         }
 225 }
 226
 227 void
 228 proto_register_sll(void)
 229 {
 230         static hf_register_info hf[] = {
 231                 { &hf_sll_pkttype,
 232                 { "Packet type",        "sll.pkttype", FT_UINT16, BASE_DEC,
 233                   VALS(packet_type_vals), 0x0, "Packet type" }},
 234
 235                 /* ARP hardware type?  With Linux extensions? */
 236                 { &hf_sll_hatype,
 237                 { "Link-layer address type",    "sll.hatype", FT_UINT16, BASE_DEC,
 238                   NULL, 0x0, "Link-layer address type" }},
 239
 240                 { &hf_sll_halen,
 241                 { "Link-layer address length",  "sll.halen", FT_UINT16, BASE_DEC,
 242                   NULL, 0x0, "Link-layer address length" }},
 243
 244                 /* Source address if it's an Ethernet-type address */
 245                 { &hf_sll_src_eth,
 246                 { "Source",     "sll.src.eth", FT_ETHER, BASE_NONE, NULL, 0x0,
 247                         "Source link-layer address" }},
 248
 249                 /* Source address if it's not an Ethernet-type address */
 250                 { &hf_sll_src_other,
 251                 { "Source",     "sll.src.other", FT_BYTES, BASE_HEX, NULL, 0x0,
 252                         "Source link-layer address" }},
 253
 254                 /* if the protocol field is an internal Linux protocol type */
 255                 { &hf_sll_ltype,
 256                 { "Protocol",   "sll.ltype", FT_UINT16, BASE_HEX,
 257                    VALS(ltype_vals), 0x0, "Linux protocol type" }},
 258
 259                 /* registered here but handled in ethertype.c */
 260                 { &hf_sll_etype,
 261                 { "Protocol",   "sll.etype", FT_UINT16, BASE_HEX,
 262                    VALS(etype_vals), 0x0, "Ethernet protocol type" }},
 263
 264                 { &hf_sll_trailer,
 265                 { "Trailer", "sll.trailer", FT_BYTES, BASE_NONE, NULL, 0x0,
 266                         "Trailer" }},
 267         };
 268         static gint *ett[] = {
 269                 &ett_sll,
 270         };
 271
 272         proto_sll = proto_register_protocol("Linux cooked-mode capture",
 273             "SLL", "sll" );
 274         proto_register_field_array(proto_sll, hf, array_length(hf));
 275         proto_register_subtree_array(ett, array_length(ett));
 276 }
 277
 278 void
 279 proto_reg_handoff_sll(void)
 280 {
 281         /*
 282          * Get handles for the IPX and LLC dissectors.
 283          */
 284         llc_handle = find_dissector("llc");
 285         ipx_handle = find_dissector("ipx");
 286
 287         dissector_add("wtap_encap", WTAP_ENCAP_SLL, dissect_sll, proto_sll);
 288 }