packet-pppoe.c

   1 /* packet-pppoe.c
   2  * Routines for PPP Over Ethernet (PPPoE) packet disassembly (RFC2516)
   3  *
   4  * $Id: packet-pppoe.c,v 1.25 2002/10/21 18:17:41 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 #include <glib.h>
  30 #include <epan/packet.h>
  31 #include <epan/strutil.h>
  32 #include "etypes.h"
  33
  34 static int proto_pppoed = -1;
  35
  36 static gint ett_pppoed = -1;
  37 static gint ett_pppoed_tags = -1;
  38
  39 static int proto_pppoes = -1;
  40
  41 static dissector_handle_t ppp_handle;
  42
  43 /* For lack of a better source, I made up the following defines. -jsj */
  44
  45 #define PPPOE_CODE_SESSION 0x00
  46 #define PPPOE_CODE_PADO 0x7
  47 #define PPPOE_CODE_PADI 0x9
  48 #define PPPOE_CODE_PADR 0x19
  49 #define PPPOE_CODE_PADS 0x65
  50 #define PPPOE_CODE_PADT 0xa7
  51
  52 #define PPPOE_TAG_EOL 0x0000
  53 #define PPPOE_TAG_SVC_NAME 0x0101
  54 #define PPPOE_TAG_AC_NAME 0x0102
  55 #define PPPOE_TAG_HOST_UNIQ 0x0103
  56 #define PPPOE_TAG_AC_COOKIE 0x0104
  57 #define PPPOE_TAG_VENDOR 0x0105
  58 #define PPPOE_TAG_RELAY_ID 0x0110
  59 #define PPPOE_TAG_SVC_ERR 0x0201
  60 #define PPPOE_TAG_AC_ERR 0x0202
  61 #define PPPOE_TAG_GENERIC_ERR 0x0203
  62
  63 static gchar *
  64 pppoecode_to_str(guint8 codetype, const char *fmt) {
  65         static const value_string code_vals[] = {
  66                 {PPPOE_CODE_SESSION, "Session Data"                             },
  67                 {PPPOE_CODE_PADO, "Active Discovery Offer (PADO)"               },
  68                 {PPPOE_CODE_PADI, "Active Discovery Initiation (PADI)"          },
  69                 {PPPOE_CODE_PADR, "Active Discovery Request (PADR)"             },
  70                 {PPPOE_CODE_PADS, "Active Discovery Session-confirmation (PADS)"},
  71                 {PPPOE_CODE_PADT, "Active Discovery Terminate (PADT)"           },
  72                 {0,     NULL                                                        } };
  73
  74                 return val_to_str(codetype, code_vals, fmt);
  75 }
  76
  77 static gchar *
  78 pppoetag_to_str(guint16 tag_type, const char *fmt) {
  79         static const value_string code_vals[] = {
  80                 {PPPOE_TAG_EOL,        "End-Of-List"       },
  81                 {PPPOE_TAG_SVC_NAME,   "Service-Name"      },
  82                 {PPPOE_TAG_AC_NAME,    "AC-Name"           },
  83                 {PPPOE_TAG_HOST_UNIQ,  "Host-Uniq"         },
  84                 {PPPOE_TAG_AC_COOKIE,  "AC-Cookie"         },
  85                 {PPPOE_TAG_VENDOR,     "Vendor-Specific"   },
  86                 {PPPOE_TAG_RELAY_ID,   "Relay-Session-Id"  },
  87                 {PPPOE_TAG_SVC_ERR,    "Service-Name-Error"},
  88                 {PPPOE_TAG_AC_ERR,     "AC-System-Error"   },
  89                 {PPPOE_TAG_GENERIC_ERR,"Generic-Error"     },
  90                 {0,                    NULL                } };
  91
  92                 return val_to_str(tag_type, code_vals, fmt);
  93 }
  94
  95
  96 static void
  97 dissect_pppoe_tags(tvbuff_t *tvb, int offset, proto_tree *tree, int payload_length) {
  98
  99         guint16 poe_tag;
 100         guint16 poe_tag_length;
 101         int tagstart;
 102
 103         proto_tree  *pppoe_tree;
 104         proto_item  *ti;
 105
 106         /* Start Decoding Here. */
 107
 108         if (tree) {
 109                 ti = proto_tree_add_text(tree, tvb,offset,payload_length,"PPPoE Tags");
 110                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed_tags);
 111
 112                 tagstart = offset;
 113                 while(tagstart <= payload_length-2 ) {
 114
 115                         poe_tag = tvb_get_ntohs(tvb, tagstart);
 116                         poe_tag_length = tvb_get_ntohs(tvb, tagstart + 2);
 117
 118                         proto_tree_add_text(pppoe_tree, tvb,tagstart,4,
 119                                 "Tag: %s", pppoetag_to_str(poe_tag,"Unknown (0x%02x)"));
 120
 121                         switch(poe_tag) {
 122                         case PPPOE_TAG_SVC_NAME:
 123                         case PPPOE_TAG_AC_NAME:
 124                         case PPPOE_TAG_SVC_ERR:
 125                         case PPPOE_TAG_AC_ERR:
 126                         case PPPOE_TAG_GENERIC_ERR:
 127                                 /* tag value should be interpreted as a utf-8 unterminated string.*/
 128                                 if(poe_tag_length > 0 ) {
 129                                         /* really should do some limit checking here.  :( */
 130                                         proto_tree_add_text(pppoe_tree, tvb,tagstart+4,poe_tag_length,
 131                                                 "  String Data: %s",
 132                                                 tvb_format_text(tvb, tagstart+4,poe_tag_length ));
 133                                 }
 134                                 break;
 135                         default:
 136                                 if(poe_tag_length > 0 ) {
 137                                  proto_tree_add_text(pppoe_tree, tvb,tagstart+4,poe_tag_length,
 138                                                 "  Binary Data: (%d bytes)", poe_tag_length );
 139                                 }
 140                         }
 141
 142                         if (poe_tag == PPPOE_TAG_EOL) break;
 143
 144                         tagstart += 4 + poe_tag_length;
 145                 }
 146         }
 147 }
 148
 149 static void
 150 dissect_pppoed(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
 151         guint8 pppoe_ver_type;
 152         guint8 pppoe_ver;
 153         guint8 pppoe_type;
 154         guint8  pppoe_code;
 155         guint16 pppoe_session_id;
 156         guint16 pppoe_length;
 157
 158         proto_tree  *pppoe_tree;
 159         proto_item  *ti;
 160
 161         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 162                 col_set_str(pinfo->cinfo,COL_PROTOCOL, "PPPoED");
 163         }
 164         if (check_col(pinfo->cinfo,COL_INFO)) {
 165                 col_clear(pinfo->cinfo,COL_INFO);
 166         }
 167
 168         /* Start Decoding Here. */
 169         pppoe_ver_type = tvb_get_guint8(tvb, 0);
 170         pppoe_ver = (pppoe_ver_type >> 4) & 0x0f;
 171         pppoe_type = pppoe_ver_type & 0x0f;
 172         pppoe_code = tvb_get_guint8(tvb, 1);
 173
 174         if (check_col(pinfo->cinfo,COL_INFO)) {
 175                 col_add_fstr(pinfo->cinfo,COL_INFO,pppoecode_to_str(pppoe_code,"Unknown code (0x%02x)"));
 176         }
 177
 178         pppoe_session_id = tvb_get_ntohs(tvb, 2);
 179         pppoe_length = tvb_get_ntohs(tvb, 4);
 180
 181         if (tree) {
 182                 ti = proto_tree_add_item(tree, proto_pppoed, tvb,0,
 183                         pppoe_length+6, FALSE);
 184                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed);
 185                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 186                         "Version: %u", pppoe_ver);
 187                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 188                         "Type: %u", pppoe_type);
 189                 proto_tree_add_text(pppoe_tree, tvb,1,1,
 190                         "Code: %s", pppoecode_to_str(pppoe_code,"Unknown (0x%02x)"));
 191                 proto_tree_add_text(pppoe_tree, tvb,2,2,
 192                         "Session ID: %04x", pppoe_session_id);
 193                 proto_tree_add_text(pppoe_tree, tvb,4,2,
 194                         "Payload Length: %u", pppoe_length);
 195         }
 196         dissect_pppoe_tags(tvb,6,tree,6+pppoe_length);
 197 }
 198
 199 void
 200 proto_register_pppoed(void)
 201 {
 202         static gint *ett[] = {
 203                 &ett_pppoed,
 204                 &ett_pppoed_tags,
 205         };
 206
 207         proto_pppoed = proto_register_protocol("PPP-over-Ethernet Discovery",
 208             "PPPoED", "pppoed");
 209
 210         proto_register_subtree_array(ett, array_length(ett));
 211 }
 212
 213 void
 214 proto_reg_handoff_pppoed(void)
 215 {
 216         dissector_handle_t pppoed_handle;
 217
 218         pppoed_handle = create_dissector_handle(dissect_pppoed, proto_pppoed);
 219         dissector_add("ethertype", ETHERTYPE_PPPOED, pppoed_handle);
 220 }
 221
 222 static void
 223 dissect_pppoes(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
 224         guint8 pppoe_ver_type;
 225         guint8 pppoe_ver;
 226         guint8 pppoe_type;
 227         guint8  pppoe_code;
 228         guint16 pppoe_session_id;
 229         guint16 pppoe_length;
 230         gint length, reported_length;
 231
 232         proto_tree  *pppoe_tree;
 233         proto_item  *ti;
 234         tvbuff_t    *next_tvb;
 235
 236         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 237                 col_set_str(pinfo->cinfo,COL_PROTOCOL, "PPPoES");
 238         }
 239         if (check_col(pinfo->cinfo,COL_INFO)) {
 240                 col_clear(pinfo->cinfo,COL_INFO);
 241         }
 242
 243         /* Start Decoding Here. */
 244         pppoe_ver_type = tvb_get_guint8(tvb, 0);
 245         pppoe_ver = (pppoe_ver_type >> 4) & 0x0f;
 246         pppoe_type = pppoe_ver_type & 0x0f;
 247         pppoe_code = tvb_get_guint8(tvb, 1);
 248
 249         if (check_col(pinfo->cinfo,COL_INFO)) {
 250                 col_add_fstr(pinfo->cinfo,COL_INFO,
 251                     pppoecode_to_str(pppoe_code,"Unknown code (0x%02x)"));
 252         }
 253
 254         pppoe_session_id = tvb_get_ntohs(tvb, 2);
 255         pppoe_length = tvb_get_ntohs(tvb, 4);
 256
 257         if (tree) {
 258                 ti = proto_tree_add_item(tree, proto_pppoes, tvb,0,
 259                         6, FALSE);
 260                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed);
 261                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 262                         "Version: %u", pppoe_ver);
 263                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 264                         "Type: %u", pppoe_type);
 265                 proto_tree_add_text(pppoe_tree, tvb,1,1,
 266                         "Code: %s", pppoecode_to_str(pppoe_code,"Unknown (0x%02x)"));
 267                 proto_tree_add_text(pppoe_tree, tvb,2,2,
 268                         "Session ID: %04x", pppoe_session_id);
 269                 proto_tree_add_text(pppoe_tree, tvb,4,2,
 270                         "Payload Length: %u", pppoe_length);
 271         }
 272         /* dissect_ppp is apparently done as a 'top level' dissector,
 273          * so this doesn't work:
 274          * dissect_ppp(pd,offset+6,pinfo->fd,tree);
 275          * Im gonna try fudging it.
 276          */
 277         length = tvb_length_remaining(tvb, 6);
 278         reported_length = tvb_reported_length_remaining(tvb, 6);
 279         g_assert(length >= 0);
 280         g_assert(reported_length >= 0);
 281         if (length > reported_length)
 282                 length = reported_length;
 283         if ((guint)length > pppoe_length)
 284                 length = pppoe_length;
 285         if ((guint)reported_length > pppoe_length)
 286                 reported_length = pppoe_length;
 287         next_tvb = tvb_new_subset(tvb,6,length,reported_length);
 288         call_dissector(ppp_handle,next_tvb,pinfo,tree);
 289 }
 290 void
 291 proto_register_pppoes(void)
 292 {
 293         proto_pppoes = proto_register_protocol("PPP-over-Ethernet Session",
 294             "PPPoES", "pppoes");
 295 }
 296
 297 void
 298 proto_reg_handoff_pppoes(void)
 299 {
 300         dissector_handle_t pppoes_handle;
 301
 302         pppoes_handle = create_dissector_handle(dissect_pppoes, proto_pppoes);
 303         dissector_add("ethertype", ETHERTYPE_PPPOES, pppoes_handle);
 304
 305         /*
 306          * Get a handle for the PPP dissector.
 307          */
 308         ppp_handle = find_dissector("ppp");
 309 }