packet-pppoe.c

   1 /* packet-pppoe.c
   2  * Routines for PPP Over Ethernet (PPPoE) packet disassembly (RFC2516)
   3  *
   4  * $Id: packet-pppoe.c,v 1.18 2001/04/17 06:43:19 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 <glib.h>
  35 #include "packet.h"
  36 #include "strutil.h"
  37 #include "etypes.h"
  38
  39 static int proto_pppoed = -1;
  40
  41 static gint ett_pppoed = -1;
  42 static gint ett_pppoed_tags = -1;
  43
  44 static int proto_pppoes = -1;
  45
  46 static dissector_handle_t ppp_handle;
  47
  48 /* For lack of a better source, I made up the following defines. -jsj */
  49
  50 #define PPPOE_CODE_SESSION 0x00
  51 #define PPPOE_CODE_PADO 0x7
  52 #define PPPOE_CODE_PADI 0x9
  53 #define PPPOE_CODE_PADR 0x19
  54 #define PPPOE_CODE_PADS 0x65
  55 #define PPPOE_CODE_PADT 0xa7
  56
  57 #define PPPOE_TAG_EOL 0x0000
  58 #define PPPOE_TAG_SVC_NAME 0x0101
  59 #define PPPOE_TAG_AC_NAME 0x0102
  60 #define PPPOE_TAG_HOST_UNIQ 0x0103
  61 #define PPPOE_TAG_AC_COOKIE 0x0104
  62 #define PPPOE_TAG_VENDOR 0x0105
  63 #define PPPOE_TAG_RELAY_ID 0x0110
  64 #define PPPOE_TAG_SVC_ERR 0x0201
  65 #define PPPOE_TAG_AC_ERR 0x0202
  66 #define PPPOE_TAG_GENERIC_ERR 0x0203
  67
  68 static gchar *
  69 pppoecode_to_str(guint8 codetype, const char *fmt) {
  70         static const value_string code_vals[] = {
  71                 {PPPOE_CODE_SESSION, "Session Data"                             },
  72                 {PPPOE_CODE_PADO, "Active Discovery Offer (PADO)"               },
  73                 {PPPOE_CODE_PADI, "Active Discovery Initiation (PADI)"          },
  74                 {PPPOE_CODE_PADR, "Active Discovery Request (PADR)"             },
  75                 {PPPOE_CODE_PADS, "Active Discovery Session-confirmation (PADS)"},
  76                 {PPPOE_CODE_PADT, "Active Discovery Terminate (PADT)"           },
  77                 {0,     NULL                                                        } };
  78
  79                 return val_to_str(codetype, code_vals, fmt);
  80 }
  81
  82 static gchar *
  83 pppoetag_to_str(guint16 tag_type, const char *fmt) {
  84         static const value_string code_vals[] = {
  85                 {PPPOE_TAG_EOL,        "End-Of-List"       },
  86                 {PPPOE_TAG_SVC_NAME,   "Service-Name"      },
  87                 {PPPOE_TAG_AC_NAME,    "AC-Name"           },
  88                 {PPPOE_TAG_HOST_UNIQ,  "Host-Uniq"         },
  89                 {PPPOE_TAG_AC_COOKIE,  "AC-Cookie"         },
  90                 {PPPOE_TAG_VENDOR,     "Vendor-Specific"   },
  91                 {PPPOE_TAG_RELAY_ID,   "Relay-Session-Id"  },
  92                 {PPPOE_TAG_SVC_ERR,    "Service-Name-Error"},
  93                 {PPPOE_TAG_AC_ERR,     "AC-System-Error"   },
  94                 {PPPOE_TAG_GENERIC_ERR,"Generic-Error"     },
  95                 {0,                    NULL                } };
  96
  97                 return val_to_str(tag_type, code_vals, fmt);
  98 }
  99
 100
 101 static void
 102 dissect_pppoe_tags(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, int payload_length) {
 103
 104         guint16 poe_tag;
 105         guint16 poe_tag_length;
 106         int tagstart;
 107
 108         proto_tree  *pppoe_tree;
 109         proto_item  *ti;
 110
 111         /* Start Decoding Here. */
 112
 113         if (tree) {
 114                 ti = proto_tree_add_text(tree, tvb,offset,payload_length,"PPPoE Tags");
 115                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed_tags);
 116
 117                 tagstart = offset;
 118                 while(tagstart <= payload_length-2 ) {
 119
 120                         poe_tag = tvb_get_ntohs(tvb, tagstart);
 121                         poe_tag_length = tvb_get_ntohs(tvb, tagstart + 2);
 122
 123                         proto_tree_add_text(pppoe_tree, tvb,tagstart,4,
 124                                 "Tag: %s", pppoetag_to_str(poe_tag,"Unknown (0x%02x)"));
 125
 126                         switch(poe_tag) {
 127                         case PPPOE_TAG_SVC_NAME:
 128                         case PPPOE_TAG_AC_NAME:
 129                         case PPPOE_TAG_SVC_ERR:
 130                         case PPPOE_TAG_AC_ERR:
 131                         case PPPOE_TAG_GENERIC_ERR:
 132                                 /* tag value should be interpreted as a utf-8 unterminated string.*/
 133                                 if(poe_tag_length > 0 ) {
 134                                         /* really should do some limit checking here.  :( */
 135                                         proto_tree_add_text(pppoe_tree, tvb,tagstart+4,poe_tag_length,
 136                                                 "  String Data: %s",
 137                                                 tvb_format_text(tvb, tagstart+4,poe_tag_length ));
 138                                 }
 139                                 break;
 140                         default:
 141                                 if(poe_tag_length > 0 ) {
 142                                  proto_tree_add_text(pppoe_tree, tvb,tagstart+4,poe_tag_length,
 143                                                 "  Binary Data: (%d bytes)", poe_tag_length );
 144                                 }
 145                         }
 146
 147                         if (poe_tag == PPPOE_TAG_EOL) break;
 148
 149                         tagstart += 4 + poe_tag_length;
 150                 }
 151         }
 152 }
 153
 154 static void
 155 dissect_pppoed(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
 156         guint8 pppoe_ver_type;
 157         guint8 pppoe_ver;
 158         guint8 pppoe_type;
 159         guint8  pppoe_code;
 160         guint16 pppoe_session_id;
 161         guint16 pppoe_length;
 162
 163         proto_tree  *pppoe_tree;
 164         proto_item  *ti;
 165
 166         if (check_col(pinfo->fd, COL_PROTOCOL)) {
 167                 col_set_str(pinfo->fd,COL_PROTOCOL, "PPPoED");
 168         }
 169         if (check_col(pinfo->fd,COL_INFO)) {
 170                 col_clear(pinfo->fd,COL_INFO);
 171         }
 172
 173         /* Start Decoding Here. */
 174         pppoe_ver_type = tvb_get_guint8(tvb, 0);
 175         pppoe_ver = (pppoe_ver_type >> 4) & 0x0f;
 176         pppoe_type = pppoe_ver_type & 0x0f;
 177         pppoe_code = tvb_get_guint8(tvb, 1);
 178
 179         if (check_col(pinfo->fd,COL_INFO)) {
 180                 col_add_fstr(pinfo->fd,COL_INFO,pppoecode_to_str(pppoe_code,"Unknown code (0x%02x)"));
 181         }
 182
 183         pppoe_session_id = tvb_get_ntohs(tvb, 2);
 184         pppoe_length = tvb_get_ntohs(tvb, 4);
 185
 186         if (tree) {
 187                 ti = proto_tree_add_item(tree, proto_pppoed, tvb,0,
 188                         pppoe_length+6, FALSE);
 189                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed);
 190                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 191                         "Version: %u", pppoe_ver);
 192                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 193                         "Type: %u", pppoe_type);
 194                 proto_tree_add_text(pppoe_tree, tvb,1,1,
 195                         "Code: %s", pppoecode_to_str(pppoe_code,"Unknown (0x%02x)"));
 196                 proto_tree_add_text(pppoe_tree, tvb,2,2,
 197                         "Session ID: %04x", pppoe_session_id);
 198                 proto_tree_add_text(pppoe_tree, tvb,4,2,
 199                         "Payload Length: %u", pppoe_length);
 200         }
 201         dissect_pppoe_tags(tvb,6,pinfo,tree,6+pppoe_length);
 202 }
 203
 204 void
 205 proto_register_pppoed(void)
 206 {
 207         static gint *ett[] = {
 208                 &ett_pppoed,
 209                 &ett_pppoed_tags,
 210         };
 211
 212         proto_pppoed = proto_register_protocol("PPP-over-Ethernet Discovery",
 213             "PPPoED", "pppoed");
 214
 215         proto_register_subtree_array(ett, array_length(ett));
 216 }
 217
 218 void
 219 proto_reg_handoff_pppoed(void)
 220 {
 221         dissector_add("ethertype", ETHERTYPE_PPPOED, dissect_pppoed,
 222             proto_pppoed);
 223 }
 224
 225 static void
 226 dissect_pppoes(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
 227         guint8 pppoe_ver_type;
 228         guint8 pppoe_ver;
 229         guint8 pppoe_type;
 230         guint8  pppoe_code;
 231         guint16 pppoe_session_id;
 232         guint16 pppoe_length;
 233
 234         proto_tree  *pppoe_tree;
 235         proto_item  *ti;
 236         tvbuff_t    *next_tvb;
 237
 238         if (check_col(pinfo->fd, COL_PROTOCOL)) {
 239                 col_set_str(pinfo->fd,COL_PROTOCOL, "PPPoES");
 240         }
 241         if (check_col(pinfo->fd,COL_INFO)) {
 242                 col_clear(pinfo->fd,COL_INFO);
 243         }
 244
 245         /* Start Decoding Here. */
 246         pppoe_ver_type = tvb_get_guint8(tvb, 0);
 247         pppoe_ver = (pppoe_ver_type >> 4) & 0x0f;
 248         pppoe_type = pppoe_ver_type & 0x0f;
 249         pppoe_code = tvb_get_guint8(tvb, 1);
 250
 251         if (check_col(pinfo->fd,COL_INFO)) {
 252                 col_add_fstr(pinfo->fd,COL_INFO,
 253                     pppoecode_to_str(pppoe_code,"Unknown code (0x%02x)"));
 254         }
 255
 256         pppoe_session_id = tvb_get_ntohs(tvb, 2);
 257         pppoe_length = tvb_get_ntohs(tvb, 4);
 258
 259         if (tree) {
 260                 ti = proto_tree_add_item(tree, proto_pppoes, tvb,0,
 261                         pppoe_length+6, FALSE);
 262                 pppoe_tree = proto_item_add_subtree(ti, ett_pppoed);
 263                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 264                         "Version: %u", pppoe_ver);
 265                 proto_tree_add_text(pppoe_tree, tvb,0,1,
 266                         "Type: %u", pppoe_type);
 267                 proto_tree_add_text(pppoe_tree, tvb,1,1,
 268                         "Code: %s", pppoecode_to_str(pppoe_code,"Unknown (0x%02x)"));
 269                 proto_tree_add_text(pppoe_tree, tvb,2,2,
 270                         "Session ID: %04x", pppoe_session_id);
 271                 proto_tree_add_text(pppoe_tree, tvb,4,2,
 272                         "Payload Length: %u", pppoe_length);
 273         }
 274         /* dissect_ppp is apparently done as a 'top level' dissector,
 275          * so this doesn't work:
 276          * dissect_ppp(pd,offset+6,pinfo->fd,tree);
 277          * Im gonna try fudging it.
 278          */
 279         next_tvb = tvb_new_subset(tvb,6,-1,-1);
 280         call_dissector(ppp_handle,next_tvb,pinfo,tree);
 281 }
 282 void
 283 proto_register_pppoes(void)
 284 {
 285         proto_pppoes = proto_register_protocol("PPP-over-Ethernet Session",
 286             "PPPoES", "pppoes");
 287 }
 288
 289 void
 290 proto_reg_handoff_pppoes(void)
 291 {
 292         dissector_add("ethertype", ETHERTYPE_PPPOES, dissect_pppoes,
 293             proto_pppoes);
 294
 295         /*
 296          * Get a handle for the PPP dissector.
 297          */
 298         ppp_handle = find_dissector("ppp");
 299 }