/* packet-pppoe.c * Routines for PPP Over Ethernet (PPPoE) packet disassembly (RFC2516) * Up to date with http://www.iana.org/assignments/pppoe-parameters (2008-04-30) * * $Id: packet-pppoe.c 27542 2009-02-25 11:25:12Z guy $ * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #include #include #include static int proto_pppoed = -1; /* Common to session and discovery protocols */ static gint hf_pppoe_version = -1; static gint hf_pppoe_type = -1; static gint hf_pppoe_code = -1; static gint hf_pppoe_session_id = -1; static gint hf_pppoe_payload_length = -1; /* Discovery protocol fields */ static gint hf_pppoed_tags = -1; static gint hf_pppoed_tag = -1; static gint hf_pppoed_tag_length = -1; static gint hf_pppoed_tag_unknown_data = -1; static gint hf_pppoed_tag_service_name = -1; static gint hf_pppoed_tag_ac_name = -1; static gint hf_pppoed_tag_host_uniq = -1; static gint hf_pppoed_tag_ac_cookie = -1; static gint hf_pppoed_tag_vendor_id = -1; static gint hf_pppoed_tag_vendor_unspecified = -1; static gint hf_pppoed_tag_credits = -1; static gint hf_pppoed_tag_credits_fcn = -1; static gint hf_pppoed_tag_credits_bcn = -1; static gint hf_pppoed_tag_metrics = -1; static gint hf_pppoed_tag_metrics_r = -1; static gint hf_pppoed_tag_metrics_rlq = -1; static gint hf_pppoed_tag_metrics_resource = -1; static gint hf_pppoed_tag_metrics_latency = -1; static gint hf_pppoed_tag_metrics_curr_drate = -1; static gint hf_pppoed_tag_metrics_max_drate = -1; static gint hf_pppoed_tag_mdr_units = -1; static gint hf_pppoed_tag_cdr_units = -1; static gint hf_pppoed_tag_seq_num = -1; static gint hf_pppoed_tag_cred_scale = -1; static gint hf_pppoed_tag_relay_session_id = -1; static gint hf_pppoed_tag_hurl = -1; static gint hf_pppoed_tag_motm = -1; static gint hf_pppoed_tag_max_payload = -1; static gint hf_pppoed_tag_ip_route_add = -1; static gint hf_pppoed_tag_service_name_error = -1; static gint hf_pppoed_tag_ac_system_error = -1; static gint hf_pppoed_tag_generic_error = -1; /* Session protocol fields */ static gint hf_pppoes_tags = -1; static gint hf_pppoes_tag = -1; static gint hf_pppoes_tag_credits = -1; static gint hf_pppoes_tag_credits_fcn = -1; static gint hf_pppoes_tag_credits_bcn = -1; /* Session protocol fields */ static gint ett_pppoed = -1; static gint ett_pppoed_tags = -1; static int proto_pppoes = -1; static gint ett_pppoes = -1; static gint ett_pppoes_tags = -1; /* PPPoE parent fields */ static int proto_pppoe = -1; static gint ett_pppoe = -1; /* Handle for calling for ppp dissector to handle session data */ static dissector_handle_t ppp_handle; /* Preference for showing discovery tag values and lengths */ static gboolean global_pppoe_show_tags_and_lengths = FALSE; #define PPPOE_CODE_SESSION 0x00 #define PPPOE_CODE_PADO 0x07 #define PPPOE_CODE_PADI 0x09 #define PPPOE_CODE_PADG 0x0a #define PPPOE_CODE_PADC 0x0b #define PPPOE_CODE_PADQ 0x0c #define PPPOE_CODE_PADR 0x19 #define PPPOE_CODE_PADS 0x65 #define PPPOE_CODE_PADT 0xa7 #define PPPOE_CODE_PADM 0xd3 #define PPPOE_CODE_PADN 0xd4 #define PPPOE_TAG_EOL 0x0000 #define PPPOE_TAG_SVC_NAME 0x0101 #define PPPOE_TAG_AC_NAME 0x0102 #define PPPOE_TAG_HOST_UNIQ 0x0103 #define PPPOE_TAG_AC_COOKIE 0x0104 #define PPPOE_TAG_VENDOR 0x0105 #define PPPOE_TAG_CREDITS 0x0106 #define PPPOE_TAG_METRICS 0x0107 #define PPPOE_TAG_SEQ_NUM 0x0108 #define PPPOE_TAG_CRED_SCALE 0x0109 #define PPPOE_TAG_RELAY_ID 0x0110 #define PPPOE_TAG_HURL 0x0111 #define PPPOE_TAG_MOTM 0x0112 #define PPPOE_TAG_MAX_PAYLD 0x0120 #define PPPOE_TAG_IP_RT_ADD 0x0121 #define PPPOE_TAG_SVC_ERR 0x0201 #define PPPOE_TAG_AC_ERR 0x0202 #define PPPOE_TAG_GENERIC_ERR 0x0203 #define PPPOE_CDR_MASK 0x06 #define PPPOE_MDR_MASK 0x18 #define PPPOE_RCV_ONLY_MASK 0x01 #define PPPOE_SCALE_KBPS 0x00 #define PPPOE_SCALE_MBPS 0x01 #define PPPOE_SCALE_GBPS 0x02 #define PPPOE_SCALE_TBPS 0x03 static const value_string code_vals[] = { {PPPOE_CODE_SESSION, "Session Data" }, {PPPOE_CODE_PADO, "Active Discovery Offer (PADO)" }, {PPPOE_CODE_PADI, "Active Discovery Initiation (PADI)" }, {PPPOE_CODE_PADG, "Active Discovery Session-Grant (PADG)" }, {PPPOE_CODE_PADC, "Active Discovery Session-Credit Resp.(PADC)" }, {PPPOE_CODE_PADQ, "Active Discovery Quality (PADQ)" }, {PPPOE_CODE_PADR, "Active Discovery Request (PADR)" }, {PPPOE_CODE_PADS, "Active Discovery Session-confirmation (PADS)"}, {PPPOE_CODE_PADT, "Active Discovery Terminate (PADT)" }, {PPPOE_CODE_PADM, "Active Discovery Message (PADM)" }, {PPPOE_CODE_PADN, "Active Discovery Network (PADN)" }, {0, NULL } }; static const value_string tag_vals[] = { {PPPOE_TAG_EOL, "End-Of-List" }, {PPPOE_TAG_SVC_NAME, "Service-Name" }, {PPPOE_TAG_AC_NAME, "AC-Name" }, {PPPOE_TAG_HOST_UNIQ, "Host-Uniq" }, {PPPOE_TAG_AC_COOKIE, "AC-Cookie" }, {PPPOE_TAG_VENDOR, "Vendor-Specific" }, {PPPOE_TAG_CREDITS, "Credits" }, {PPPOE_TAG_METRICS, "Metrics" }, {PPPOE_TAG_SEQ_NUM, "Seqence Number" }, {PPPOE_TAG_CRED_SCALE, "Credit Scale Factor"}, {PPPOE_TAG_RELAY_ID, "Relay-Session-Id" }, {PPPOE_TAG_HURL, "HURL" }, {PPPOE_TAG_MOTM, "MOTM" }, {PPPOE_TAG_MAX_PAYLD, "PPP-Max-Payload" }, {PPPOE_TAG_IP_RT_ADD, "IP Route Add" }, {PPPOE_TAG_SVC_ERR, "Service-Name-Error"}, {PPPOE_TAG_AC_ERR, "AC-System-Error" }, {PPPOE_TAG_GENERIC_ERR,"Generic-Error" }, {0, NULL } }; const value_string datarate_scale_vals[] = { {PPPOE_SCALE_KBPS, "kilobits per second"}, {PPPOE_SCALE_MBPS, "megabits per second"}, {PPPOE_SCALE_GBPS, "gigabits per second"}, {PPPOE_SCALE_TBPS, "terabits per second"}, {0, NULL } }; /* Dissect discovery protocol tags */ static void dissect_pppoe_tags(tvbuff_t *tvb, packet_info *pinfo, int offset, proto_tree *tree, int payload_length) { guint16 poe_tag; guint16 poe_tag_length; int tagstart; guint16 poe_rsv = 0; proto_tree *pppoe_tree; proto_item *ti; /* Start Decoding Here. */ if (tree) { /* Create tags subtree */ ti = proto_tree_add_item(tree, hf_pppoed_tags, tvb, offset, payload_length-6, FALSE); pppoe_tree = proto_item_add_subtree(ti, ett_pppoed_tags); tagstart = offset; /* Loop until all data seen or End-Of-List tag found */ while (tagstart <= payload_length-2) { poe_tag = tvb_get_ntohs(tvb, tagstart); poe_tag_length = tvb_get_ntohs(tvb, tagstart + 2); /* Tag value and data length */ if (global_pppoe_show_tags_and_lengths) { proto_tree_add_item(pppoe_tree, hf_pppoed_tag, tvb, tagstart, 2, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoed_tag_length, tvb, tagstart+2, 2, FALSE); } /* Show tag data */ switch (poe_tag) { case PPPOE_TAG_SVC_NAME: if (poe_tag_length > 0) { proto_tree_add_item(pppoe_tree, hf_pppoed_tag_service_name, tvb, tagstart+4, poe_tag_length, FALSE); } break; case PPPOE_TAG_AC_NAME: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ac_name, tvb, tagstart+4, poe_tag_length, FALSE); /* Show AC-Name in info column */ if (check_col(pinfo->cinfo, COL_INFO)) { col_append_fstr(pinfo->cinfo, COL_INFO, " AC-Name='%s'", tvb_get_ephemeral_string(tvb, tagstart+4, poe_tag_length)); } break; case PPPOE_TAG_HOST_UNIQ: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_host_uniq, tvb, tagstart+4, poe_tag_length, FALSE); break; case PPPOE_TAG_AC_COOKIE: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ac_cookie, tvb, tagstart+4, poe_tag_length, FALSE); break; case PPPOE_TAG_VENDOR: if (poe_tag_length >= 4) { proto_tree_add_item(pppoe_tree, hf_pppoed_tag_vendor_id, tvb, tagstart+4, 4, FALSE); } if (poe_tag_length > 4) { proto_tree_add_item(pppoe_tree, hf_pppoed_tag_vendor_unspecified, tvb, tagstart+4+4, poe_tag_length-4, FALSE); } break; case PPPOE_TAG_CREDITS: if (poe_tag_length == 4) { proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits_fcn, tvb, tagstart+4, 2, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits_bcn, tvb, tagstart+6, 2, FALSE); } else { proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits, tvb, tagstart+4, poe_tag_length, FALSE); } break; case PPPOE_TAG_METRICS: if (poe_tag_length == 10) { poe_rsv = tvb_get_ntohs(tvb, tagstart+4); proto_tree_add_item(pppoe_tree, hf_pppoed_tag_mdr_units, tvb, tagstart+4, 2, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoed_tag_cdr_units, tvb, tagstart+4, 2, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_r, tvb, tagstart+4, 2, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_rlq, tvb, tagstart+6, 1, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_resource, tvb, tagstart+7, 1, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_latency, tvb, tagstart+8, 2, FALSE); /* CDR */ ti = proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_curr_drate, tvb, tagstart+10, 2, FALSE); switch ((poe_rsv & PPPOE_CDR_MASK) >> 1) { case (PPPOE_SCALE_KBPS): proto_item_append_text(ti, " kbps"); break; case (PPPOE_SCALE_MBPS): proto_item_append_text(ti, " mbps"); break; case (PPPOE_SCALE_GBPS): proto_item_append_text(ti, " gbps"); break; case (PPPOE_SCALE_TBPS): proto_item_append_text(ti, " tbps"); break; } /* MDR */ ti = proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics_max_drate, tvb, tagstart+12, 2, FALSE); switch ((poe_rsv & PPPOE_MDR_MASK) >> 3) { case (PPPOE_SCALE_KBPS): proto_item_append_text(ti, " kbps"); break; case (PPPOE_SCALE_MBPS): proto_item_append_text(ti, " mbps"); break; case (PPPOE_SCALE_GBPS): proto_item_append_text(ti, " gbps"); break; case (PPPOE_SCALE_TBPS): proto_item_append_text(ti, " tbps"); break; } } else { proto_tree_add_item(pppoe_tree, hf_pppoed_tag_metrics, tvb, tagstart+4, poe_tag_length, FALSE); } break; case PPPOE_TAG_SEQ_NUM: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_seq_num, tvb, tagstart+4, poe_tag_length, FALSE); break; case PPPOE_TAG_CRED_SCALE: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_cred_scale, tvb, tagstart+4, poe_tag_length, FALSE); break; case PPPOE_TAG_RELAY_ID: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_relay_session_id, tvb, tagstart+4, poe_tag_length, FALSE); break; case PPPOE_TAG_HURL: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_hurl, tvb, tagstart+4, poe_tag_length, FALSE); break; case PPPOE_TAG_MOTM: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_motm, tvb, tagstart+4, poe_tag_length, FALSE); break; case PPPOE_TAG_MAX_PAYLD: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_max_payload, tvb, tagstart+4, poe_tag_length, FALSE); break; case PPPOE_TAG_IP_RT_ADD: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ip_route_add, tvb, tagstart+4, poe_tag_length, FALSE); break; /* These error tag values should be interpreted as a utf-8 unterminated strings. */ case PPPOE_TAG_SVC_ERR: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_service_name_error, tvb, tagstart+4, poe_tag_length, FALSE); break; case PPPOE_TAG_AC_ERR: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_ac_system_error, tvb, tagstart+4, poe_tag_length, FALSE); break; case PPPOE_TAG_GENERIC_ERR: proto_tree_add_item(pppoe_tree, hf_pppoed_tag_generic_error, tvb, tagstart+4, poe_tag_length, FALSE); break; /* Get out if see end-of-list tag */ case PPPOE_TAG_EOL: return; default: if (poe_tag_length > 0 ) { /* Presumably unknown tag; show tag value if we didn't do it above */ if (!global_pppoe_show_tags_and_lengths) { proto_tree_add_item(pppoe_tree, hf_pppoed_tag, tvb, tagstart, 2, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoed_tag_length, tvb, tagstart+2, 2, FALSE); } proto_tree_add_item(pppoe_tree, hf_pppoed_tag_unknown_data, tvb, tagstart+4, poe_tag_length, FALSE); } } tagstart += (4 + poe_tag_length); } } } /* Discovery protocol, i.e. PPP session not yet established */ static void dissect_pppoed(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { guint8 pppoe_code; guint16 reported_payload_length; proto_tree *pppoe_tree = NULL; proto_item *ti; if (check_col(pinfo->cinfo, COL_PROTOCOL)) { col_set_str(pinfo->cinfo, COL_PROTOCOL, "PPPoED"); } if (check_col(pinfo->cinfo, COL_INFO)) { col_clear(pinfo->cinfo, COL_INFO); } /* Start Decoding Here. */ pppoe_code = tvb_get_guint8(tvb, 1); if (check_col(pinfo->cinfo, COL_INFO)) { col_append_str(pinfo->cinfo, COL_INFO, val_to_str(pppoe_code, code_vals, "Unknown")); } /* Read length of payload */ reported_payload_length = tvb_get_ntohs(tvb, 4); if (tree) { ti = proto_tree_add_item(tree, proto_pppoed, tvb, 0, reported_payload_length+6, FALSE); pppoe_tree = proto_item_add_subtree(ti, ett_pppoed); /* Dissect fixed fields */ proto_tree_add_item(pppoe_tree, hf_pppoe_version, tvb, 0, 1, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoe_type, tvb, 0, 1, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoe_code, tvb, 1, 1, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoe_session_id, tvb, 2, 2, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoe_payload_length, tvb, 4, 2, FALSE); } /* Now dissect any tags */ if (reported_payload_length > 0) { dissect_pppoe_tags(tvb, pinfo, 6, pppoe_tree, 6+reported_payload_length); } } void proto_register_pppoed(void) { static hf_register_info hf[] = { /* Discovery tag fields */ { &hf_pppoed_tags, { "PPPoE Tags", "pppoed.tags", FT_NONE, BASE_NONE, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag, { "Tag", "pppoed.tag", FT_UINT16, BASE_HEX, VALS(tag_vals), 0x0, "", HFILL } }, { &hf_pppoed_tag_length, { "Tag Length", "pppoed.tag_length", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_unknown_data, { "Unknown Data", "pppoed.tag.unknown_data", FT_BYTES, BASE_NONE, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_service_name, { "Service-Name", "pppoed.tags.service_name", FT_STRING, BASE_NONE, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_ac_name, { "AC-Name", "pppoed.tags.ac_name", FT_STRING, BASE_NONE, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_host_uniq, { "Host-Uniq", "pppoed.tags.host_uniq", FT_BYTES, BASE_NONE, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_ac_cookie, { "AC-Cookie", "pppoed.tags.ac_cookie", FT_BYTES, BASE_NONE, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_vendor_id, { "Vendor id", "pppoed.tags.vendor_id", FT_UINT32, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_vendor_unspecified, { "Vendor unspecified", "pppoed.tags.vendor_unspecified", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_credits, { "Credits", "pppoed.tags.credits", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_credits_fcn, { "FCN", "pppoed.tags.credits.fcn", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_credits_bcn, { "BCN", "pppoed.tags.credits.bcn", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_metrics, { "Metrics", "pppoed.tags.metrics", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_metrics_r, { "Receive Only", "pppoed.tags.metrics.r", FT_BOOLEAN, 16, NULL, PPPOE_RCV_ONLY_MASK, "", HFILL } }, { &hf_pppoed_tag_mdr_units, { "MDR Units", "pppoed.tags.metrics.mdr_units", FT_UINT16, BASE_HEX, VALS(datarate_scale_vals), PPPOE_MDR_MASK, "", HFILL } }, { &hf_pppoed_tag_cdr_units, { "CDR Units", "pppoed.tags.metrics.cdr_units", FT_UINT16, BASE_HEX, VALS(datarate_scale_vals), PPPOE_CDR_MASK, "", HFILL } }, { &hf_pppoed_tag_metrics_rlq, { "Relative Link Quality", "pppoed.tags.metrics.rlq", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_metrics_resource, { "Resource", "pppoed.tags.metrics.resource", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_metrics_latency, { "Latency", "pppoed.tags.metrics.latency", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_metrics_curr_drate, { "Curr. datarate", "pppoed.tags.metrics.curr_drate", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_metrics_max_drate, { "Max. datarate", "pppoed.tags.metrics.max_drate", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_seq_num, { "Sequence Number", "pppoed.tags.seq_num", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_cred_scale, { "Credit Scale Factor", "pppoed.tags.credit_scale", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_relay_session_id, { "Relay-Session-Id", "pppoed.tags.relay_session_id", FT_BYTES, BASE_NONE, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_hurl, { "HURL", "pppoed.tags.hurl", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_motm, { "MOTM", "pppoed.tags.motm", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_max_payload, { "PPP Max Palyload", "pppoed.tags.max_payload", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_ip_route_add, { "IP Route Add", "pppoed.tags.ip_route_add", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_service_name_error, { "Service-Name-Error", "pppoed.tags.service_name_error", FT_STRING, BASE_NONE, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_ac_system_error, { "AC-System-Error", "pppoed.tags.ac_system_error", FT_STRING, BASE_NONE, NULL, 0x0, "", HFILL } }, { &hf_pppoed_tag_generic_error, { "Generic-Error", "pppoed.tags.generic_error", FT_STRING, BASE_NONE, NULL, 0x0, "", HFILL } } }; static gint *ett[] = { &ett_pppoed, &ett_pppoed_tags }; module_t *pppoed_module; /* Register protocol and fields */ proto_pppoed = proto_register_protocol("PPP-over-Ethernet Discovery", "PPPoED", "pppoed"); proto_register_subtree_array(ett, array_length(ett)); proto_register_field_array(proto_pppoed, hf, array_length(hf)); /* Preference setting */ pppoed_module = prefs_register_protocol(proto_pppoed, NULL); prefs_register_bool_preference(pppoed_module, "show_tags_and_lengths", "Show tag values and lengths", "Show values of tags and lengths of data fields", &global_pppoe_show_tags_and_lengths); } void proto_reg_handoff_pppoed(void) { dissector_handle_t pppoed_handle; pppoed_handle = create_dissector_handle(dissect_pppoed, proto_pppoed); dissector_add("ethertype", ETHERTYPE_PPPOED, pppoed_handle); } /* Session protocol, i.e. PPP session established */ static void dissect_pppoes(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { guint8 pppoe_code; guint16 pppoe_session_id; guint16 reported_payload_length; guint16 poe_tag; guint16 poe_tag_length; gint actual_payload_length; gint length, reported_length; gint credit_offset = 0, tagstart = 0; proto_tree *pppoe_tree; proto_item *ti = NULL; tvbuff_t *next_tvb; if (check_col(pinfo->cinfo, COL_PROTOCOL)) { col_set_str(pinfo->cinfo,COL_PROTOCOL, "PPPoES"); } if (check_col(pinfo->cinfo,COL_INFO)) { col_clear(pinfo->cinfo,COL_INFO); } /* Start Decoding Here. */ pppoe_code = tvb_get_guint8(tvb, 1); if (check_col(pinfo->cinfo,COL_INFO)) { col_add_str(pinfo->cinfo, COL_INFO, val_to_str(pppoe_code, code_vals, "Unknown")); } pppoe_session_id = tvb_get_ntohs(tvb, 2); reported_payload_length = tvb_get_ntohs(tvb, 4); actual_payload_length = tvb_reported_length_remaining(tvb, 6); if (tree) { ti = proto_tree_add_item(tree, proto_pppoes, tvb, 0, 6, FALSE); pppoe_tree = proto_item_add_subtree(ti, ett_pppoe); proto_tree_add_item(pppoe_tree, hf_pppoe_version, tvb, 0, 1, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoe_type, tvb, 0, 1, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoe_code, tvb, 1, 1, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoe_session_id, tvb, 2, 2, FALSE); ti = proto_tree_add_item(pppoe_tree, hf_pppoe_payload_length, tvb, 4, 2, FALSE); if (PPPOE_TAG_CREDITS == tvb_get_ntohs(tvb, 6)) { tagstart = 6; poe_tag = tvb_get_ntohs(tvb, tagstart); poe_tag_length = tvb_get_ntohs(tvb, tagstart + 2); /* Create tags subtree */ ti = proto_tree_add_item(pppoe_tree, hf_pppoes_tags, tvb, tagstart, 8, FALSE); pppoe_tree = proto_item_add_subtree(ti, ett_pppoes_tags); /* Show tag data */ if (poe_tag_length == 4) { proto_tree_add_item(pppoe_tree, hf_pppoes_tag_credits_fcn, tvb, tagstart+4, 2, FALSE); proto_tree_add_item(pppoe_tree, hf_pppoes_tag_credits_bcn, tvb, tagstart+6, 2, FALSE); } else { proto_tree_add_item(pppoe_tree, hf_pppoed_tag_credits, tvb, tagstart+4, poe_tag_length, FALSE); } credit_offset = 8; } } /* * The only reason why the payload length from the header * should differ from the remaining data in the packet * would be if the total packet length, including Ethernet * CRC, were < 64 bytes, so that padding was required. * * That means that you have 14 bytes of Ethernet header, * 4 bytes of FCS, and fewer than 46 bytes of PPPoE packet. * * If that's not the case, we report a difference between * the payload length in the packet, and the amount of * data following the PPPoE header, as an error. */ if (tvb_reported_length(tvb) > 46) { /* * Be forgiving about a possible trailing FCS. * * XXX - this dissector currently doesn't know * whether any extra data past the end of the PPP * payload is an FCS or not. * * If we know that we have an FCS, or that we don't * have an FCS, we should have been handed a tvbuff * without the FCS, and we should just do the strict * length check. * * If we don't know whether we have an FCS, then: * * if this isn't over Ethernet - the "E" in "PPPoE" * nonwithstanding, it can also run on top of 802.11, * for example - there's no trailer, so any data * past the payload length is either an FCS or * bogus; * * if this is over Ethernet, there shouldn't be * a trailer, as the packet is long enough not to * require a trailer, as per the above; * * so perhaps we should assume that if we have exactly * 4 bytes of extra information, it's an FCS, otherwise * it's not. * * Perhaps we need to have a routine to call to * do all the length checking, etc., and call it * from here and from other dissectors where the * protocol has a length field, or have a way to * tell the dissector that called us which field * has the length field and have *that* dissector * do the length checking and add the expert info * to the length field, *after* it does all the * FCS heuristics. */ if ((reported_payload_length != actual_payload_length) && ((reported_payload_length + 4) != actual_payload_length)) { proto_item_append_text(ti, " [incorrect, should be %u]", actual_payload_length); expert_add_info_format(pinfo, ti, PI_MALFORMED, PI_WARN, "Possible bad payload length %u != %u", reported_payload_length, actual_payload_length); } } /* * Construct a tvbuff containing the PPP packet. */ length = tvb_length_remaining(tvb, 6); reported_length = tvb_reported_length_remaining(tvb, 6); DISSECTOR_ASSERT(length >= 0); DISSECTOR_ASSERT(reported_length >= 0); if (length > reported_length) length = reported_length; if ((guint)length > reported_payload_length) length = reported_payload_length; if ((guint)reported_length > reported_payload_length) reported_length = reported_payload_length; next_tvb = tvb_new_subset(tvb,(6 + credit_offset), (length - credit_offset), (reported_length - credit_offset)); call_dissector(ppp_handle,next_tvb,pinfo,tree); } void proto_register_pppoes(void) { static hf_register_info hf[] = { { &hf_pppoes_tags, { "PPPoE Tags", "pppoes.tags", FT_NONE, BASE_NONE, NULL, 0x0, "", HFILL } }, { &hf_pppoes_tag, { "Tag", "pppoes.tag", FT_UINT16, BASE_HEX, VALS(tag_vals), 0x0, "", HFILL } }, { &hf_pppoes_tag_credits, { "Credits", "pppoes.tags.credits", FT_BYTES, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoes_tag_credits_fcn, { "FCN", "pppoes.tags.credits.fcn", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_pppoes_tag_credits_bcn, { "BCN", "pppoes.tags.credits.bcn", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL } } }; static gint *ett[] = { &ett_pppoes, &ett_pppoes_tags }; /* Register protocol */ proto_pppoes = proto_register_protocol("PPP-over-Ethernet Session", "PPPoES", "pppoes"); proto_register_subtree_array(ett, array_length(ett)); proto_register_field_array(proto_pppoes, hf, array_length(hf)); } void proto_register_pppoe(void) { static hf_register_info hf[] = { /* These fields common to discovery and session protocols */ { &hf_pppoe_version, { "Version", "pppoe.version", FT_UINT8, BASE_DEC, NULL, 0xf0, "", HFILL } }, { &hf_pppoe_type, { "Type", "pppoe.type", FT_UINT8, BASE_DEC, NULL, 0x0f, "", HFILL } }, { &hf_pppoe_code, { "Code", "pppoe.code", FT_UINT8, BASE_HEX, VALS(code_vals), 0x0, "", HFILL } }, { &hf_pppoe_session_id, { "Session ID", "pppoe.session_id", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL } }, { &hf_pppoe_payload_length, { "Payload Length", "pppoe.payload_length", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL } } }; static gint *ett[] = { &ett_pppoe }; /* Register protocol */ proto_pppoe = proto_register_protocol("PPP-over-Ethernet", "PPPoE", "pppoe"); proto_register_subtree_array(ett, array_length(ett)); proto_register_field_array(proto_pppoe, hf, array_length(hf)); } void proto_reg_handoff_pppoes(void) { dissector_handle_t pppoes_handle = create_dissector_handle(dissect_pppoes, proto_pppoes); dissector_add("ethertype", ETHERTYPE_PPPOES, pppoes_handle); /* Get a handle for the PPP dissector */ ppp_handle = find_dissector("ppp"); }