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 1.11 2001/07/16 05:16:58 guy 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 #include "etypes.h"
  42
  43 static int proto_sll = -1;
  44 static int hf_sll_pkttype = -1;
  45 static int hf_sll_hatype = -1;
  46 static int hf_sll_halen = -1;
  47 static int hf_sll_src_eth = -1;
  48 static int hf_sll_src_other = -1;
  49 static int hf_sll_ltype = -1;
  50 static int hf_sll_etype = -1;
  51 static int hf_sll_trailer = -1;
  52
  53 static gint ett_sll = -1;
  54
  55 /*
  56  * A DLT_LINUX_SLL fake link-layer header.
  57  */
  58 #define SLL_HEADER_SIZE 16              /* total header length */
  59 #define SLL_ADDRLEN     8               /* length of address field */
  60
  61 /*
  62  * The LINUX_SLL_ values for "sll_pkttype".
  63  */
  64 #define LINUX_SLL_HOST          0
  65 #define LINUX_SLL_BROADCAST     1
  66 #define LINUX_SLL_MULTICAST     2
  67 #define LINUX_SLL_OTHERHOST     3
  68 #define LINUX_SLL_OUTGOING      4
  69
  70 static const value_string packet_type_vals[] = {
  71         { LINUX_SLL_HOST,       "Unicast to us" },
  72         { LINUX_SLL_BROADCAST,  "Broadcast" },
  73         { LINUX_SLL_MULTICAST,  "Multicast" },
  74         { LINUX_SLL_OTHERHOST,  "Unicast to another host" },
  75         { LINUX_SLL_OUTGOING,   "Sent by us" },
  76         { 0,                    NULL }
  77 };
  78
  79 /*
  80  * The LINUX_SLL_ values for "sll_protocol".
  81  */
  82 #define LINUX_SLL_P_802_3       0x0001  /* Novell 802.3 frames without 802.2 LLC header */
  83 #define LINUX_SLL_P_802_2       0x0004  /* 802.2 frames (not D/I/X Ethernet) */
  84
  85 static const value_string ltype_vals[] = {
  86         { LINUX_SLL_P_802_3,    "Raw 802.3" },
  87         { LINUX_SLL_P_802_2,    "802.2 LLC" },
  88         { 0,                    NULL }
  89 };
  90
  91 static dissector_handle_t ipx_handle;
  92 static dissector_handle_t llc_handle;
  93
  94 void
  95 capture_sll(const u_char *pd, packet_counts *ld)
  96 {
  97         guint16 protocol;
  98
  99         if (!BYTES_ARE_IN_FRAME(0, SLL_HEADER_SIZE)) {
 100                 ld->other++;
 101                 return;
 102         }
 103         protocol = pntohs(&pd[14]);
 104         if (protocol <= 1536) { /* yes, 1536 - that's how Linux does it */
 105                 /*
 106                  * "proto" is *not* a length field, it's a Linux internal
 107                  * protocol type.
 108                  */
 109                 switch (protocol) {
 110
 111                 case LINUX_SLL_P_802_2:
 112                         /*
 113                          * 802.2 LLC.
 114                          */
 115                         capture_llc(pd, SLL_HEADER_SIZE, ld);
 116                         break;
 117
 118                 case LINUX_SLL_P_802_3:
 119                         /*
 120                          * Novell IPX inside 802.3 with no 802.2 LLC
 121                          * header.
 122                          */
 123                         capture_ipx(pd, SLL_HEADER_SIZE, ld);
 124                         break;
 125
 126                 default:
 127                         ld->other++;
 128                         break;
 129                 }
 130         } else
 131                 capture_ethertype(protocol, SLL_HEADER_SIZE, pd, ld);
 132 }
 133
 134 static void
 135 dissect_sll(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 136 {
 137         guint16 pkttype;
 138         guint16 protocol;
 139         guint16 hatype, halen;
 140         const guint8 *src;
 141         proto_item *ti;
 142         tvbuff_t *next_tvb;
 143         proto_tree *fh_tree = NULL;
 144
 145         if (check_col(pinfo->fd, COL_PROTOCOL))
 146                 col_set_str(pinfo->fd, COL_PROTOCOL, "SLL");
 147         if (check_col(pinfo->fd, COL_INFO))
 148                 col_clear(pinfo->fd, COL_INFO);
 149
 150         pkttype = tvb_get_ntohs(tvb, 0);
 151
 152         if (check_col(pinfo->fd, COL_INFO))
 153                 col_add_str(pinfo->fd, COL_INFO,
 154                     val_to_str(pkttype, packet_type_vals, "Unknown (%u)"));
 155
 156         if (tree) {
 157                 ti = proto_tree_add_protocol_format(tree, proto_sll, tvb, 0,
 158                     SLL_HEADER_SIZE, "Linux cooked capture");
 159                 fh_tree = proto_item_add_subtree(ti, ett_sll);
 160                 proto_tree_add_item(fh_tree, hf_sll_pkttype, tvb, 0, 2, FALSE);
 161         }
 162
 163         /*
 164          * XXX - check the link-layer address type value?
 165          * For now, we just assume 6 means Ethernet.
 166          */
 167         hatype = tvb_get_ntohs(tvb, 2);
 168         halen = tvb_get_ntohs(tvb, 4);
 169         if (tree) {
 170                 proto_tree_add_uint(fh_tree, hf_sll_hatype, tvb, 2, 2, hatype);
 171                 proto_tree_add_uint(fh_tree, hf_sll_halen, tvb, 4, 2, halen);
 172         }
 173         if (halen == 6) {
 174                 src = tvb_get_ptr(tvb, 6, 6);
 175                 SET_ADDRESS(&pinfo->dl_src, AT_ETHER, 6, src);
 176                 SET_ADDRESS(&pinfo->src, AT_ETHER, 6, src);
 177                 if (tree) {
 178                         proto_tree_add_ether(fh_tree, hf_sll_src_eth, tvb,
 179                             6, 6, src);
 180                 }
 181         } else {
 182                 if (tree) {
 183                         proto_tree_add_item(fh_tree, hf_sll_src_other, tvb,
 184                             6, halen, FALSE);
 185                 }
 186         }
 187
 188         protocol = tvb_get_ntohs(tvb, 14);
 189         if (protocol <= 1536) { /* yes, 1536 - that's how Linux does it */
 190                 /*
 191                  * "proto" is *not* a length field, it's a Linux internal
 192                  * protocol type.
 193                  * We therefore cannot say how much of the packet will
 194                  * be trailer data.
 195                  * XXX - do the same thing we do for packets with Ethertypes?
 196                  */
 197                 proto_tree_add_uint(fh_tree, hf_sll_ltype, tvb, 14, 2,
 198                     protocol);
 199
 200                 next_tvb = tvb_new_subset(tvb, SLL_HEADER_SIZE, -1, -1);
 201                 switch (protocol) {
 202
 203                 case LINUX_SLL_P_802_2:
 204                         /*
 205                          * 802.2 LLC.
 206                          */
 207                         call_dissector(llc_handle, next_tvb, pinfo, tree);
 208                         break;
 209
 210                 case LINUX_SLL_P_802_3:
 211                         /*
 212                          * Novell IPX inside 802.3 with no 802.2 LLC
 213                          * header.
 214                          */
 215                         call_dissector(ipx_handle, next_tvb, pinfo, tree);
 216                         break;
 217
 218                 default:
 219                         dissect_data(next_tvb, 0, pinfo, tree);
 220                         break;
 221                 }
 222         } else {
 223                 ethertype(protocol, tvb, SLL_HEADER_SIZE, pinfo, tree,
 224                     fh_tree, hf_sll_etype, hf_sll_trailer);
 225         }
 226 }
 227
 228 void
 229 proto_register_sll(void)
 230 {
 231         static hf_register_info hf[] = {
 232                 { &hf_sll_pkttype,
 233                 { "Packet type",        "sll.pkttype", FT_UINT16, BASE_DEC,
 234                   VALS(packet_type_vals), 0x0, "Packet type", HFILL }},
 235
 236                 /* ARP hardware type?  With Linux extensions? */
 237                 { &hf_sll_hatype,
 238                 { "Link-layer address type",    "sll.hatype", FT_UINT16, BASE_DEC,
 239                   NULL, 0x0, "Link-layer address type", HFILL }},
 240
 241                 { &hf_sll_halen,
 242                 { "Link-layer address length",  "sll.halen", FT_UINT16, BASE_DEC,
 243                   NULL, 0x0, "Link-layer address length", HFILL }},
 244
 245                 /* Source address if it's an Ethernet-type address */
 246                 { &hf_sll_src_eth,
 247                 { "Source",     "sll.src.eth", FT_ETHER, BASE_NONE, NULL, 0x0,
 248                         "Source link-layer address", HFILL }},
 249
 250                 /* Source address if it's not an Ethernet-type address */
 251                 { &hf_sll_src_other,
 252                 { "Source",     "sll.src.other", FT_BYTES, BASE_HEX, NULL, 0x0,
 253                         "Source link-layer address", HFILL }},
 254
 255                 /* if the protocol field is an internal Linux protocol type */
 256                 { &hf_sll_ltype,
 257                 { "Protocol",   "sll.ltype", FT_UINT16, BASE_HEX,
 258                    VALS(ltype_vals), 0x0, "Linux protocol type", HFILL }},
 259
 260                 /* registered here but handled in ethertype.c */
 261                 { &hf_sll_etype,
 262                 { "Protocol",   "sll.etype", FT_UINT16, BASE_HEX,
 263                    VALS(etype_vals), 0x0, "Ethernet protocol type", HFILL }},
 264
 265                 { &hf_sll_trailer,
 266                 { "Trailer", "sll.trailer", FT_BYTES, BASE_NONE, NULL, 0x0,
 267                         "Trailer", HFILL }},
 268         };
 269         static gint *ett[] = {
 270                 &ett_sll,
 271         };
 272
 273         proto_sll = proto_register_protocol("Linux cooked-mode capture",
 274             "SLL", "sll" );
 275         proto_register_field_array(proto_sll, hf, array_length(hf));
 276         proto_register_subtree_array(ett, array_length(ett));
 277 }
 278
 279 void
 280 proto_reg_handoff_sll(void)
 281 {
 282         /*
 283          * Get handles for the IPX and LLC dissectors.
 284          */
 285         llc_handle = find_dissector("llc");
 286         ipx_handle = find_dissector("ipx");
 287
 288         dissector_add("wtap_encap", WTAP_ENCAP_SLL, dissect_sll, proto_sll);
 289 }