packet-pppoe.c

   1 /* packet-pppoe.c
   2  * Routines for PPP Over Ethernet (PPPoE) packet disassembly (RFC2516)
   3  *
   4  * $Id: packet-pppoe.c,v 1.21 2002/01/21 07:36:38 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 <glib.h>
  34 #include <epan/packet.h>
  35 #include <epan/strutil.h>
  36 #include "etypes.h"
  37
  38 static int proto_pppoed = -1;
  39
  40 static gint ett_pppoed = -1;
  41 static gint ett_pppoed_tags = -1;
  42
  43 static int proto_pppoes = -1;
  44
  45 static dissector_handle_t ppp_handle;
  46
  47 /* For lack of a better source, I made up the following defines. -jsj */
  48
  49 #define PPPOE_CODE_SESSION 0x00
  50 #define PPPOE_CODE_PADO 0x7
  51 #define PPPOE_CODE_PADI 0x9
  52 #define PPPOE_CODE_PADR 0x19
  53 #define PPPOE_CODE_PADS 0x65
  54 #define PPPOE_CODE_PADT 0xa7
  55
  56 #define PPPOE_TAG_EOL 0x0000
  57 #define PPPOE_TAG_SVC_NAME 0x0101
  58 #define PPPOE_TAG_AC_NAME 0x0102
  59 #define PPPOE_TAG_HOST_UNIQ 0x0103
  60 #define PPPOE_TAG_AC_COOKIE 0x0104
  61 #define PPPOE_TAG_VENDOR 0x0105
  62 #define PPPOE_TAG_RELAY_ID 0x0110
  63 #define PPPOE_TAG_SVC_ERR 0x0201
  64 #define PPPOE_TAG_AC_ERR 0x0202
  65 #define PPPOE_TAG_GENERIC_ERR 0x0203
  66
  67 static gchar *
  68 pppoecode_to_str(guint8 codetype, const char *fmt) {
  69         static const value_string code_vals[] = {
  70                 {PPPOE_CODE_SESSION, "Session Data"                             },
  71                 {PPPOE_CODE_PADO, "Active Discovery Offer (PADO)"               },
  72                 {PPPOE_CODE_PADI, "Active Discovery Initiation (PADI)"          },
  73                 {PPPOE_CODE_PADR, "Active Discovery Request (PADR)"             },
  74                 {PPPOE_CODE_PADS, "Active Discovery Session-confirmation (PADS)"},
  75                 {PPPOE_CODE_PADT, "Active Discovery Terminate (PADT)"           },
  76                 {0,     NULL                                                        } };
  77
  78                 return val_to_str(codetype, code_vals, fmt);
  79 }
  80
  81 static gchar *
  82 pppoetag_to_str(guint16 tag_type, const char *fmt) {
  83         static const value_string code_vals[] = {
  84                 {PPPOE_TAG_EOL,        "End-Of-List"       },
  85                 {PPPOE_TAG_SVC_NAME,   "Service-Name"      },
  86                 {PPPOE_TAG_AC_NAME,    "AC-Name"           },
  87                 {PPPOE_TAG_HOST_UNIQ,  "Host-Uniq"         },
  88                 {PPPOE_TAG_AC_COOKIE,  "AC-Cookie"         },
  89                 {PPPOE_TAG_VENDOR,     "Vendor-Specific"   },
  90                 {PPPOE_TAG_RELAY_ID,   "Relay-Session-Id"  },
  91                 {PPPOE_TAG_SVC_ERR,    "Service-Name-Error"},
  92                 {PPPOE_TAG_AC_ERR,     "AC-System-Error"   },
  93                 {PPPOE_TAG_GENERIC_ERR,"Generic-Error"     },
  94                 {0,                    NULL                } };
  95
  96                 return val_to_str(tag_type, code_vals, fmt);
  97 }
  98
  99
 100 static void
 101 dissect_pppoe_tags(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, int payload_length) {
 102
 103         guint16 poe_tag;
 104         guint16 poe_tag_length;
 105         int tagstart;
 106
 107         proto_tree  *pppoe_tree;
 108         proto_item  *ti;
 109
 110         /* Start Decoding Here. */
 111
 112         if (tree) {
 113                 ti = proto_tree_add_text(tree, tvb,offset,payload_length,"PPPoE Tags");
 114                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed_tags);
 115
 116                 tagstart = offset;
 117                 while(tagstart <= payload_length-2 ) {
 118
 119                         poe_tag = tvb_get_ntohs(tvb, tagstart);
 120                         poe_tag_length = tvb_get_ntohs(tvb, tagstart + 2);
 121
 122                         proto_tree_add_text(pppoe_tree, tvb,tagstart,4,
 123                                 "Tag: %s", pppoetag_to_str(poe_tag,"Unknown (0x%02x)"));
 124
 125                         switch(poe_tag) {
 126                         case PPPOE_TAG_SVC_NAME:
 127                         case PPPOE_TAG_AC_NAME:
 128                         case PPPOE_TAG_SVC_ERR:
 129                         case PPPOE_TAG_AC_ERR:
 130                         case PPPOE_TAG_GENERIC_ERR:
 131                                 /* tag value should be interpreted as a utf-8 unterminated string.*/
 132                                 if(poe_tag_length > 0 ) {
 133                                         /* really should do some limit checking here.  :( */
 134                                         proto_tree_add_text(pppoe_tree, tvb,tagstart+4,poe_tag_length,
 135                                                 "  String Data: %s",
 136                                                 tvb_format_text(tvb, tagstart+4,poe_tag_length ));
 137                                 }
 138                                 break;
 139                         default:
 140                                 if(poe_tag_length > 0 ) {
 141                                  proto_tree_add_text(pppoe_tree, tvb,tagstart+4,poe_tag_length,
 142                                                 "  Binary Data: (%d bytes)", poe_tag_length );
 143                                 }
 144                         }
 145
 146                         if (poe_tag == PPPOE_TAG_EOL) break;
 147
 148                         tagstart += 4 + poe_tag_length;
 149                 }
 150         }
 151 }
 152
 153 static void
 154 dissect_pppoed(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
 155         guint8 pppoe_ver_type;
 156         guint8 pppoe_ver;
 157         guint8 pppoe_type;
 158         guint8  pppoe_code;
 159         guint16 pppoe_session_id;
 160         guint16 pppoe_length;
 161
 162         proto_tree  *pppoe_tree;
 163         proto_item  *ti;
 164
 165         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 166                 col_set_str(pinfo->cinfo,COL_PROTOCOL, "PPPoED");
 167         }
 168         if (check_col(pinfo->cinfo,COL_INFO)) {
 169                 col_clear(pinfo->cinfo,COL_INFO);
 170         }
 171
 172         /* Start Decoding Here. */
 173         pppoe_ver_type = tvb_get_guint8(tvb, 0);
 174         pppoe_ver = (pppoe_ver_type >> 4) & 0x0f;
 175         pppoe_type = pppoe_ver_type & 0x0f;
 176         pppoe_code = tvb_get_guint8(tvb, 1);
 177
 178         if (check_col(pinfo->cinfo,COL_INFO)) {
 179                 col_add_fstr(pinfo->cinfo,COL_INFO,pppoecode_to_str(pppoe_code,"Unknown code (0x%02x)"));
 180         }
 181
 182         pppoe_session_id = tvb_get_ntohs(tvb, 2);
 183         pppoe_length = tvb_get_ntohs(tvb, 4);
 184
 185         if (tree) {
 186                 ti = proto_tree_add_item(tree, proto_pppoed, tvb,0,
 187                         pppoe_length+6, FALSE);
 188                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed);
 189                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 190                         "Version: %u", pppoe_ver);
 191                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 192                         "Type: %u", pppoe_type);
 193                 proto_tree_add_text(pppoe_tree, tvb,1,1,
 194                         "Code: %s", pppoecode_to_str(pppoe_code,"Unknown (0x%02x)"));
 195                 proto_tree_add_text(pppoe_tree, tvb,2,2,
 196                         "Session ID: %04x", pppoe_session_id);
 197                 proto_tree_add_text(pppoe_tree, tvb,4,2,
 198                         "Payload Length: %u", pppoe_length);
 199         }
 200         dissect_pppoe_tags(tvb,6,pinfo,tree,6+pppoe_length);
 201 }
 202
 203 void
 204 proto_register_pppoed(void)
 205 {
 206         static gint *ett[] = {
 207                 &ett_pppoed,
 208                 &ett_pppoed_tags,
 209         };
 210
 211         proto_pppoed = proto_register_protocol("PPP-over-Ethernet Discovery",
 212             "PPPoED", "pppoed");
 213
 214         proto_register_subtree_array(ett, array_length(ett));
 215 }
 216
 217 void
 218 proto_reg_handoff_pppoed(void)
 219 {
 220         dissector_handle_t pppoed_handle;
 221
 222         pppoed_handle = create_dissector_handle(dissect_pppoed, proto_pppoed);
 223         dissector_add("ethertype", ETHERTYPE_PPPOED, pppoed_handle);
 224 }
 225
 226 static void
 227 dissect_pppoes(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
 228         guint8 pppoe_ver_type;
 229         guint8 pppoe_ver;
 230         guint8 pppoe_type;
 231         guint8  pppoe_code;
 232         guint16 pppoe_session_id;
 233         guint16 pppoe_length;
 234
 235         proto_tree  *pppoe_tree;
 236         proto_item  *ti;
 237         tvbuff_t    *next_tvb;
 238
 239         if (check_col(pinfo->cinfo, COL_PROTOCOL)) {
 240                 col_set_str(pinfo->cinfo,COL_PROTOCOL, "PPPoES");
 241         }
 242         if (check_col(pinfo->cinfo,COL_INFO)) {
 243                 col_clear(pinfo->cinfo,COL_INFO);
 244         }
 245
 246         /* Start Decoding Here. */
 247         pppoe_ver_type = tvb_get_guint8(tvb, 0);
 248         pppoe_ver = (pppoe_ver_type >> 4) & 0x0f;
 249         pppoe_type = pppoe_ver_type & 0x0f;
 250         pppoe_code = tvb_get_guint8(tvb, 1);
 251
 252         if (check_col(pinfo->cinfo,COL_INFO)) {
 253                 col_add_fstr(pinfo->cinfo,COL_INFO,
 254                     pppoecode_to_str(pppoe_code,"Unknown code (0x%02x)"));
 255         }
 256
 257         pppoe_session_id = tvb_get_ntohs(tvb, 2);
 258         pppoe_length = tvb_get_ntohs(tvb, 4);
 259
 260         if (tree) {
 261                 ti = proto_tree_add_item(tree, proto_pppoes, tvb,0,
 262                         pppoe_length+6, FALSE);
 263                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed);
 264                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 265                         "Version: %u", pppoe_ver);
 266                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 267                         "Type: %u", pppoe_type);
 268                 proto_tree_add_text(pppoe_tree, tvb,1,1,
 269                         "Code: %s", pppoecode_to_str(pppoe_code,"Unknown (0x%02x)"));
 270                 proto_tree_add_text(pppoe_tree, tvb,2,2,
 271                         "Session ID: %04x", pppoe_session_id);
 272                 proto_tree_add_text(pppoe_tree, tvb,4,2,
 273                         "Payload Length: %u", pppoe_length);
 274         }
 275         /* dissect_ppp is apparently done as a 'top level' dissector,
 276          * so this doesn't work:
 277          * dissect_ppp(pd,offset+6,pinfo->fd,tree);
 278          * Im gonna try fudging it.
 279          */
 280         next_tvb = tvb_new_subset(tvb,6,-1,-1);
 281         call_dissector(ppp_handle,next_tvb,pinfo,tree);
 282 }
 283 void
 284 proto_register_pppoes(void)
 285 {
 286         proto_pppoes = proto_register_protocol("PPP-over-Ethernet Session",
 287             "PPPoES", "pppoes");
 288 }
 289
 290 void
 291 proto_reg_handoff_pppoes(void)
 292 {
 293         dissector_handle_t pppoes_handle;
 294
 295         pppoes_handle = create_dissector_handle(dissect_pppoes, proto_pppoes);
 296         dissector_add("ethertype", ETHERTYPE_PPPOES, pppoes_handle);
 297
 298         /*
 299          * Get a handle for the PPP dissector.
 300          */
 301         ppp_handle = find_dissector("ppp");
 302 }