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 1.19 2002/08/28 21:00:31 jmayer 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 #include <stdio.h>
  30 #include <string.h>
  31 #include <glib.h>
  32 #include <epan/packet.h>
  33 #include "packet-sll.h"
  34 #include "packet-ipx.h"
  35 #include "packet-llc.h"
  36 #include <epan/resolv.h>
  37 #include "etypes.h"
  38
  39 static int proto_sll = -1;
  40 static int hf_sll_pkttype = -1;
  41 static int hf_sll_hatype = -1;
  42 static int hf_sll_halen = -1;
  43 static int hf_sll_src_eth = -1;
  44 static int hf_sll_src_other = -1;
  45 static int hf_sll_ltype = -1;
  46 static int hf_sll_etype = -1;
  47 static int hf_sll_trailer = -1;
  48
  49 static gint ett_sll = -1;
  50
  51 /*
  52  * A DLT_LINUX_SLL fake link-layer header.
  53  */
  54 #define SLL_HEADER_SIZE 16              /* total header length */
  55 #define SLL_ADDRLEN     8               /* length of address field */
  56
  57 /*
  58  * The LINUX_SLL_ values for "sll_pkttype".
  59  */
  60 #define LINUX_SLL_HOST          0
  61 #define LINUX_SLL_BROADCAST     1
  62 #define LINUX_SLL_MULTICAST     2
  63 #define LINUX_SLL_OTHERHOST     3
  64 #define LINUX_SLL_OUTGOING      4
  65
  66 static const value_string packet_type_vals[] = {
  67         { LINUX_SLL_HOST,       "Unicast to us" },
  68         { LINUX_SLL_BROADCAST,  "Broadcast" },
  69         { LINUX_SLL_MULTICAST,  "Multicast" },
  70         { LINUX_SLL_OTHERHOST,  "Unicast to another host" },
  71         { LINUX_SLL_OUTGOING,   "Sent by us" },
  72         { 0,                    NULL }
  73 };
  74
  75 /*
  76  * The LINUX_SLL_ values for "sll_protocol".
  77  */
  78 #define LINUX_SLL_P_802_3       0x0001  /* Novell 802.3 frames without 802.2 LLC header */
  79 #define LINUX_SLL_P_802_2       0x0004  /* 802.2 frames (not D/I/X Ethernet) */
  80
  81 static const value_string ltype_vals[] = {
  82         { LINUX_SLL_P_802_3,    "Raw 802.3" },
  83         { LINUX_SLL_P_802_2,    "802.2 LLC" },
  84         { 0,                    NULL }
  85 };
  86
  87 static dissector_handle_t ipx_handle;
  88 static dissector_handle_t llc_handle;
  89 static dissector_handle_t data_handle;
  90
  91 void
  92 capture_sll(const guchar *pd, int len, packet_counts *ld)
  93 {
  94         guint16 protocol;
  95
  96         if (!BYTES_ARE_IN_FRAME(0, len, SLL_HEADER_SIZE)) {
  97                 ld->other++;
  98                 return;
  99         }
 100         protocol = pntohs(&pd[14]);
 101         if (protocol <= 1536) { /* yes, 1536 - that's how Linux does it */
 102                 /*
 103                  * "proto" is *not* a length field, it's a Linux internal
 104                  * protocol type.
 105                  */
 106                 switch (protocol) {
 107
 108                 case LINUX_SLL_P_802_2:
 109                         /*
 110                          * 802.2 LLC.
 111                          */
 112                         capture_llc(pd, len, SLL_HEADER_SIZE, ld);
 113                         break;
 114
 115                 case LINUX_SLL_P_802_3:
 116                         /*
 117                          * Novell IPX inside 802.3 with no 802.2 LLC
 118                          * header.
 119                          */
 120                         capture_ipx(ld);
 121                         break;
 122
 123                 default:
 124                         ld->other++;
 125                         break;
 126                 }
 127         } else
 128                 capture_ethertype(protocol, pd, SLL_HEADER_SIZE, len, ld);
 129 }
 130
 131 static void
 132 dissect_sll(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 133 {
 134         guint16 pkttype;
 135         guint16 protocol;
 136         guint16 hatype, halen;
 137         const guint8 *src;
 138         proto_item *ti;
 139         tvbuff_t *next_tvb;
 140         proto_tree *fh_tree = NULL;
 141
 142         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 143                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "SLL");
 144         if (check_col(pinfo->cinfo, COL_INFO))
 145                 col_clear(pinfo->cinfo, COL_INFO);
 146
 147         pkttype = tvb_get_ntohs(tvb, 0);
 148
 149         if (check_col(pinfo->cinfo, COL_INFO))
 150                 col_add_str(pinfo->cinfo, COL_INFO,
 151                     val_to_str(pkttype, packet_type_vals, "Unknown (%u)"));
 152
 153         if (tree) {
 154                 ti = proto_tree_add_protocol_format(tree, proto_sll, tvb, 0,
 155                     SLL_HEADER_SIZE, "Linux cooked capture");
 156                 fh_tree = proto_item_add_subtree(ti, ett_sll);
 157                 proto_tree_add_item(fh_tree, hf_sll_pkttype, tvb, 0, 2, FALSE);
 158         }
 159
 160         /*
 161          * XXX - check the link-layer address type value?
 162          * For now, we just assume 6 means Ethernet.
 163          */
 164         hatype = tvb_get_ntohs(tvb, 2);
 165         halen = tvb_get_ntohs(tvb, 4);
 166         if (tree) {
 167                 proto_tree_add_uint(fh_tree, hf_sll_hatype, tvb, 2, 2, hatype);
 168                 proto_tree_add_uint(fh_tree, hf_sll_halen, tvb, 4, 2, halen);
 169         }
 170         if (halen == 6) {
 171                 src = tvb_get_ptr(tvb, 6, 6);
 172                 SET_ADDRESS(&pinfo->dl_src, AT_ETHER, 6, src);
 173                 SET_ADDRESS(&pinfo->src, AT_ETHER, 6, src);
 174                 if (tree) {
 175                         proto_tree_add_ether(fh_tree, hf_sll_src_eth, tvb,
 176                             6, 6, src);
 177                 }
 178         } else {
 179                 if (tree) {
 180                         proto_tree_add_item(fh_tree, hf_sll_src_other, tvb,
 181                             6, halen, FALSE);
 182                 }
 183         }
 184
 185         protocol = tvb_get_ntohs(tvb, 14);
 186         if (protocol <= 1536) { /* yes, 1536 - that's how Linux does it */
 187                 /*
 188                  * "proto" is *not* a length field, it's a Linux internal
 189                  * protocol type.
 190                  * We therefore cannot say how much of the packet will
 191                  * be trailer data.
 192                  * XXX - do the same thing we do for packets with Ethertypes?
 193                  */
 194                 proto_tree_add_uint(fh_tree, hf_sll_ltype, tvb, 14, 2,
 195                     protocol);
 196
 197                 next_tvb = tvb_new_subset(tvb, SLL_HEADER_SIZE, -1, -1);
 198                 switch (protocol) {
 199
 200                 case LINUX_SLL_P_802_2:
 201                         /*
 202                          * 802.2 LLC.
 203                          */
 204                         call_dissector(llc_handle, next_tvb, pinfo, tree);
 205                         break;
 206
 207                 case LINUX_SLL_P_802_3:
 208                         /*
 209                          * Novell IPX inside 802.3 with no 802.2 LLC
 210                          * header.
 211                          */
 212                         call_dissector(ipx_handle, next_tvb, pinfo, tree);
 213                         break;
 214
 215                 default:
 216                         call_dissector(data_handle,next_tvb, pinfo, tree);
 217                         break;
 218                 }
 219         } else {
 220                 ethertype(protocol, tvb, SLL_HEADER_SIZE, pinfo, tree,
 221                     fh_tree, hf_sll_etype, hf_sll_trailer);
 222         }
 223 }
 224
 225 void
 226 proto_register_sll(void)
 227 {
 228         static hf_register_info hf[] = {
 229                 { &hf_sll_pkttype,
 230                 { "Packet type",        "sll.pkttype", FT_UINT16, BASE_DEC,
 231                   VALS(packet_type_vals), 0x0, "Packet type", HFILL }},
 232
 233                 /* ARP hardware type?  With Linux extensions? */
 234                 { &hf_sll_hatype,
 235                 { "Link-layer address type",    "sll.hatype", FT_UINT16, BASE_DEC,
 236                   NULL, 0x0, "Link-layer address type", HFILL }},
 237
 238                 { &hf_sll_halen,
 239                 { "Link-layer address length",  "sll.halen", FT_UINT16, BASE_DEC,
 240                   NULL, 0x0, "Link-layer address length", HFILL }},
 241
 242                 /* Source address if it's an Ethernet-type address */
 243                 { &hf_sll_src_eth,
 244                 { "Source",     "sll.src.eth", FT_ETHER, BASE_NONE, NULL, 0x0,
 245                         "Source link-layer address", HFILL }},
 246
 247                 /* Source address if it's not an Ethernet-type address */
 248                 { &hf_sll_src_other,
 249                 { "Source",     "sll.src.other", FT_BYTES, BASE_HEX, NULL, 0x0,
 250                         "Source link-layer address", HFILL }},
 251
 252                 /* if the protocol field is an internal Linux protocol type */
 253                 { &hf_sll_ltype,
 254                 { "Protocol",   "sll.ltype", FT_UINT16, BASE_HEX,
 255                    VALS(ltype_vals), 0x0, "Linux protocol type", HFILL }},
 256
 257                 /* registered here but handled in ethertype.c */
 258                 { &hf_sll_etype,
 259                 { "Protocol",   "sll.etype", FT_UINT16, BASE_HEX,
 260                    VALS(etype_vals), 0x0, "Ethernet protocol type", HFILL }},
 261
 262                 { &hf_sll_trailer,
 263                 { "Trailer", "sll.trailer", FT_BYTES, BASE_NONE, NULL, 0x0,
 264                         "Trailer", HFILL }},
 265         };
 266         static gint *ett[] = {
 267                 &ett_sll,
 268         };
 269
 270         proto_sll = proto_register_protocol("Linux cooked-mode capture",
 271             "SLL", "sll" );
 272         proto_register_field_array(proto_sll, hf, array_length(hf));
 273         proto_register_subtree_array(ett, array_length(ett));
 274 }
 275
 276 void
 277 proto_reg_handoff_sll(void)
 278 {
 279         dissector_handle_t sll_handle;
 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         data_handle = find_dissector("data");
 287
 288         sll_handle = create_dissector_handle(dissect_sll, proto_sll);
 289         dissector_add("wtap_encap", WTAP_ENCAP_SLL, sll_handle);
 290 }