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 1.16 2002/01/21 07:36:42 guy Exp $
   5  *
   6  * Ethereal - Network traffic analyzer
   7  * By Gerald Combs <gerald@ethereal.com>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #ifdef HAVE_SYS_TYPES_H
  30 # include <sys/types.h>
  31 #endif
  32
  33 #include <stdio.h>
  34 #include <string.h>
  35 #include <glib.h>
  36 #include <epan/packet.h>
  37 #include "packet-sll.h"
  38 #include "packet-ipx.h"
  39 #include "packet-llc.h"
  40 #include <epan/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 static dissector_handle_t data_handle;
  94
  95 void
  96 capture_sll(const u_char *pd, int len, packet_counts *ld)
  97 {
  98         guint16 protocol;
  99
 100         if (!BYTES_ARE_IN_FRAME(0, len, SLL_HEADER_SIZE)) {
 101                 ld->other++;
 102                 return;
 103         }
 104         protocol = pntohs(&pd[14]);
 105         if (protocol <= 1536) { /* yes, 1536 - that's how Linux does it */
 106                 /*
 107                  * "proto" is *not* a length field, it's a Linux internal
 108                  * protocol type.
 109                  */
 110                 switch (protocol) {
 111
 112                 case LINUX_SLL_P_802_2:
 113                         /*
 114                          * 802.2 LLC.
 115                          */
 116                         capture_llc(pd, len, SLL_HEADER_SIZE, ld);
 117                         break;
 118
 119                 case LINUX_SLL_P_802_3:
 120                         /*
 121                          * Novell IPX inside 802.3 with no 802.2 LLC
 122                          * header.
 123                          */
 124                         capture_ipx(pd, len, SLL_HEADER_SIZE, ld);
 125                         break;
 126
 127                 default:
 128                         ld->other++;
 129                         break;
 130                 }
 131         } else
 132                 capture_ethertype(protocol, pd, SLL_HEADER_SIZE, len, ld);
 133 }
 134
 135 static void
 136 dissect_sll(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 137 {
 138         guint16 pkttype;
 139         guint16 protocol;
 140         guint16 hatype, halen;
 141         const guint8 *src;
 142         proto_item *ti;
 143         tvbuff_t *next_tvb;
 144         proto_tree *fh_tree = NULL;
 145
 146         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 147                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "SLL");
 148         if (check_col(pinfo->cinfo, COL_INFO))
 149                 col_clear(pinfo->cinfo, COL_INFO);
 150
 151         pkttype = tvb_get_ntohs(tvb, 0);
 152
 153         if (check_col(pinfo->cinfo, COL_INFO))
 154                 col_add_str(pinfo->cinfo, COL_INFO,
 155                     val_to_str(pkttype, packet_type_vals, "Unknown (%u)"));
 156
 157         if (tree) {
 158                 ti = proto_tree_add_protocol_format(tree, proto_sll, tvb, 0,
 159                     SLL_HEADER_SIZE, "Linux cooked capture");
 160                 fh_tree = proto_item_add_subtree(ti, ett_sll);
 161                 proto_tree_add_item(fh_tree, hf_sll_pkttype, tvb, 0, 2, FALSE);
 162         }
 163
 164         /*
 165          * XXX - check the link-layer address type value?
 166          * For now, we just assume 6 means Ethernet.
 167          */
 168         hatype = tvb_get_ntohs(tvb, 2);
 169         halen = tvb_get_ntohs(tvb, 4);
 170         if (tree) {
 171                 proto_tree_add_uint(fh_tree, hf_sll_hatype, tvb, 2, 2, hatype);
 172                 proto_tree_add_uint(fh_tree, hf_sll_halen, tvb, 4, 2, halen);
 173         }
 174         if (halen == 6) {
 175                 src = tvb_get_ptr(tvb, 6, 6);
 176                 SET_ADDRESS(&pinfo->dl_src, AT_ETHER, 6, src);
 177                 SET_ADDRESS(&pinfo->src, AT_ETHER, 6, src);
 178                 if (tree) {
 179                         proto_tree_add_ether(fh_tree, hf_sll_src_eth, tvb,
 180                             6, 6, src);
 181                 }
 182         } else {
 183                 if (tree) {
 184                         proto_tree_add_item(fh_tree, hf_sll_src_other, tvb,
 185                             6, halen, FALSE);
 186                 }
 187         }
 188
 189         protocol = tvb_get_ntohs(tvb, 14);
 190         if (protocol <= 1536) { /* yes, 1536 - that's how Linux does it */
 191                 /*
 192                  * "proto" is *not* a length field, it's a Linux internal
 193                  * protocol type.
 194                  * We therefore cannot say how much of the packet will
 195                  * be trailer data.
 196                  * XXX - do the same thing we do for packets with Ethertypes?
 197                  */
 198                 proto_tree_add_uint(fh_tree, hf_sll_ltype, tvb, 14, 2,
 199                     protocol);
 200
 201                 next_tvb = tvb_new_subset(tvb, SLL_HEADER_SIZE, -1, -1);
 202                 switch (protocol) {
 203
 204                 case LINUX_SLL_P_802_2:
 205                         /*
 206                          * 802.2 LLC.
 207                          */
 208                         call_dissector(llc_handle, next_tvb, pinfo, tree);
 209                         break;
 210
 211                 case LINUX_SLL_P_802_3:
 212                         /*
 213                          * Novell IPX inside 802.3 with no 802.2 LLC
 214                          * header.
 215                          */
 216                         call_dissector(ipx_handle, next_tvb, pinfo, tree);
 217                         break;
 218
 219                 default:
 220                         call_dissector(data_handle,next_tvb, pinfo, tree);
 221                         break;
 222                 }
 223         } else {
 224                 ethertype(protocol, tvb, SLL_HEADER_SIZE, pinfo, tree,
 225                     fh_tree, hf_sll_etype, hf_sll_trailer);
 226         }
 227 }
 228
 229 void
 230 proto_register_sll(void)
 231 {
 232         static hf_register_info hf[] = {
 233                 { &hf_sll_pkttype,
 234                 { "Packet type",        "sll.pkttype", FT_UINT16, BASE_DEC,
 235                   VALS(packet_type_vals), 0x0, "Packet type", HFILL }},
 236
 237                 /* ARP hardware type?  With Linux extensions? */
 238                 { &hf_sll_hatype,
 239                 { "Link-layer address type",    "sll.hatype", FT_UINT16, BASE_DEC,
 240                   NULL, 0x0, "Link-layer address type", HFILL }},
 241
 242                 { &hf_sll_halen,
 243                 { "Link-layer address length",  "sll.halen", FT_UINT16, BASE_DEC,
 244                   NULL, 0x0, "Link-layer address length", HFILL }},
 245
 246                 /* Source address if it's an Ethernet-type address */
 247                 { &hf_sll_src_eth,
 248                 { "Source",     "sll.src.eth", FT_ETHER, BASE_NONE, NULL, 0x0,
 249                         "Source link-layer address", HFILL }},
 250
 251                 /* Source address if it's not an Ethernet-type address */
 252                 { &hf_sll_src_other,
 253                 { "Source",     "sll.src.other", FT_BYTES, BASE_HEX, NULL, 0x0,
 254                         "Source link-layer address", HFILL }},
 255
 256                 /* if the protocol field is an internal Linux protocol type */
 257                 { &hf_sll_ltype,
 258                 { "Protocol",   "sll.ltype", FT_UINT16, BASE_HEX,
 259                    VALS(ltype_vals), 0x0, "Linux protocol type", HFILL }},
 260
 261                 /* registered here but handled in ethertype.c */
 262                 { &hf_sll_etype,
 263                 { "Protocol",   "sll.etype", FT_UINT16, BASE_HEX,
 264                    VALS(etype_vals), 0x0, "Ethernet protocol type", HFILL }},
 265
 266                 { &hf_sll_trailer,
 267                 { "Trailer", "sll.trailer", FT_BYTES, BASE_NONE, NULL, 0x0,
 268                         "Trailer", HFILL }},
 269         };
 270         static gint *ett[] = {
 271                 &ett_sll,
 272         };
 273
 274         proto_sll = proto_register_protocol("Linux cooked-mode capture",
 275             "SLL", "sll" );
 276         proto_register_field_array(proto_sll, hf, array_length(hf));
 277         proto_register_subtree_array(ett, array_length(ett));
 278 }
 279
 280 void
 281 proto_reg_handoff_sll(void)
 282 {
 283         dissector_handle_t sll_handle;
 284
 285         /*
 286          * Get handles for the IPX and LLC dissectors.
 287          */
 288         llc_handle = find_dissector("llc");
 289         ipx_handle = find_dissector("ipx");
 290         data_handle = find_dissector("data");
 291
 292         sll_handle = create_dissector_handle(dissect_sll, proto_sll);
 293         dissector_add("wtap_encap", WTAP_ENCAP_SLL, sll_handle);
 294 }