/* packet-msdp.c * Routines for Multicast Source Discovery Protocol (MSDP) dissection. * draft-ietf-msdp-spec-10.txt * * Copyright 2001, Heikki Vatiainen * * $Id: packet-msdp.c,v 1.8 2003/01/20 06:24:37 guy Exp $ * * Ethereal - 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 /* MSDP message types. The messages are TLV (Type-Length-Value) encoded */ enum { MSDP_SA = 1, MSDP_SA_REQ, MSDP_SA_RSP, MSDP_KEEP_ALIVE, MSDP_NOTIFICATION, /* Theses are only assigned in MSDP spec. Their use is specifed * elsewhere */ MSDP_TRACE_IN_PROGRESS, MSDP_TRACE_REPLY }; static const value_string msdp_types[] = { { MSDP_SA, "IPv4 Source-Active" }, { MSDP_SA_REQ, "IPv4 Source-Active Request" }, { MSDP_SA_RSP, "IPv4 Source-Active Response" }, { MSDP_KEEP_ALIVE, "KeepAlive" }, { MSDP_NOTIFICATION, "Notification" }, { MSDP_TRACE_IN_PROGRESS, "MSDP traceroute in progresss" }, { MSDP_TRACE_REPLY, "MSDP traceroute reply" }, { 0, NULL }, }; /* Error codes */ enum { MESSAGE_HEADER_ERROR = 1, SA_REQUEST_ERROR, SA_MESSAGE_SA_RESPONSE_ERROR, HOLD_TIMER_EXPIRED, FSM_ERROR, NOTIFICATION, CEASE }; static const value_string error_vals[] = { { MESSAGE_HEADER_ERROR, "Message Header Error" }, { SA_REQUEST_ERROR, "SA-Request Error" }, { SA_MESSAGE_SA_RESPONSE_ERROR, "SA-Message/SA-Response Error" }, { HOLD_TIMER_EXPIRED, "Hold Timer Expired" }, { FSM_ERROR, "Finite State Machine Error" }, { NOTIFICATION, "Notification" }, { CEASE, "Cease" }, { 0, NULL }, }; /* Message Header Error subcodes */ static const value_string hdr_error_vals[] = { { 0, "Unspecific" }, { 2, "Bad Message Length" }, { 3, "Bad Message Type" }, { 0, NULL }, }; /* SA-Request Error subcodes (the O-bit is always clear) */ static const value_string sa_req_error_vals[] = { { 0, "Unspecific" }, { 1, "Invalid Group" }, { 0, NULL }, }; /* SA-Message/SA-Response Error subcodes */ static const value_string sa_msg_error_vals[] = { { 0, "Unspecific" }, { 1, "Invalid Entry Count" }, { 2, "Invalid RP Address" }, { 3, "Invalid Group Address" }, { 4, "Invalid Source Address" }, { 5, "Invalid Sprefix Length" }, { 6, "Looping SA (Self is RP)" }, { 7, "Unknown Encapsulation" }, { 8, "Administrative Scope Boundary Violated" }, { 0, NULL }, }; /* Finite State Machine Error subcodes (the O-bit is always clear) */ static const value_string fsm_error_vals[] = { { 0, "Unspecific" }, { 1, "Unexpected Message Type FSM Error" }, { 0, NULL }, }; /* * Hold Timer Expired subcodes (the O-bit is always clear): * Notification subcodes (the O-bit is always clear): * Cease subcodes (the O-bit is always clear): * * These have only "Unspecific" specified. */ static const value_string sa_unspec_error_vals[] = { { 0, "Unspecific" }, { 0, NULL }, }; /* Initialize the protocol and registered fields */ static int proto_msdp = -1; static int hf_msdp_type = -1; static int hf_msdp_length = -1; static int hf_msdp_sa_entry_count = -1; static int hf_msdp_sa_rp_addr = -1; static int hf_msdp_sa_reserved = -1; static int hf_msdp_sa_sprefix_len = -1; static int hf_msdp_sa_group_addr = -1; static int hf_msdp_sa_src_addr = -1; static int hf_msdp_sa_req_res = -1; static int hf_msdp_sa_req_group = -1; static int hf_msdp_not_o = -1; static int hf_msdp_not_error = -1; static int hf_msdp_not_error_sub = -1; static int hf_msdp_not_ipv4 = -1; static int hf_msdp_not_res = -1; static int hf_msdp_not_entry_count = -1; static int hf_msdp_not_sprefix_len = -1; static gint ett_msdp = -1; static gint ett_msdp_sa_entry = -1; static gint ett_msdp_sa_enc_data = -1; static gint ett_msdp_not_data = -1; static dissector_handle_t ip_handle; static void dissect_msdp_sa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int *offset, int len); static void dissect_msdp_notification(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int *offset, guint16 tlv_len); static void dissect_msdp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_item *ti; proto_tree *msdp_tree; int offset; if (check_col(pinfo->cinfo, COL_PROTOCOL)) col_set_str(pinfo->cinfo, COL_PROTOCOL, "MSDP"); if (check_col(pinfo->cinfo, COL_INFO)) col_set_str(pinfo->cinfo, COL_INFO, val_to_str(tvb_get_guint8(tvb, 0), msdp_types, "")); if (tree) { guint8 type; guint16 length; ti = proto_tree_add_item(tree, proto_msdp, tvb, 0, -1, FALSE); msdp_tree = proto_item_add_subtree(ti, ett_msdp); offset = 0; while (tvb_reported_length_remaining(tvb, offset) >= 3) { type = tvb_get_guint8(tvb, offset); length = tvb_get_ntohs(tvb, offset + 1); if (length < 3) break; proto_tree_add_uint(msdp_tree, hf_msdp_type, tvb, offset, 1, type); proto_tree_add_uint(msdp_tree, hf_msdp_length, tvb, offset + 1, 2, length); offset += 3; length -= 3; switch (type) { case MSDP_SA: case MSDP_SA_RSP: dissect_msdp_sa(tvb, pinfo, msdp_tree, &offset, length); break; case MSDP_SA_REQ: proto_tree_add_item(msdp_tree, hf_msdp_sa_req_res, tvb, offset, 1, FALSE); proto_tree_add_item(msdp_tree, hf_msdp_sa_req_group, tvb, offset + 1, 4, FALSE); offset += 5; break; case MSDP_NOTIFICATION: dissect_msdp_notification(tvb, pinfo, msdp_tree, &offset, length); break; default: if (length > 0) proto_tree_add_text(msdp_tree, tvb, offset, length, "TLV contents"); offset += length; break; } } if (tvb_length_remaining(tvb, offset) > 0) proto_tree_add_text(msdp_tree, tvb, offset, -1, "Trailing junk"); } return; } /* Both Source-Active and Source-Active Response have the same format * with one exception. Encapsulated multicast data is not allowed in * SA Response. */ static void dissect_msdp_sa(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int *offset, int length) { guint8 entries; guint32 rp_addr; if (length < 1) return; entries = tvb_get_guint8(tvb, *offset); proto_tree_add_uint(tree, hf_msdp_sa_entry_count, tvb, *offset, 1, entries); *offset += 1; length -= 1; if (length < 4) { *offset += length; length = 0; return; } tvb_memcpy(tvb, (guint8 *)&rp_addr, *offset, 4); proto_tree_add_item(tree, hf_msdp_sa_rp_addr, tvb, *offset, 4, FALSE); *offset += 4; length -= 4; /* Put each of the (S,G) entries in their own subtree. * This is probably visually better. */ while (entries-- > 0) { proto_item *ei; proto_tree *entry_tree; if (length < 12) { *offset += length; length = 0; return; } ei = proto_tree_add_text(tree, tvb, *offset, 12, "(S,G) block: %s/%u -> %s", ip_to_str(tvb_get_ptr(tvb, *offset + 8, 4)), tvb_get_guint8(tvb, *offset + 3), ip_to_str(tvb_get_ptr(tvb, *offset + 4, 4))); entry_tree = proto_item_add_subtree(ei, ett_msdp_sa_entry); proto_tree_add_item(entry_tree, hf_msdp_sa_reserved, tvb, *offset, 3, FALSE); *offset += 3; length -= 3; proto_tree_add_item(entry_tree, hf_msdp_sa_sprefix_len, tvb, *offset, 1, FALSE); *offset += 1; length -= 1; proto_tree_add_item(entry_tree, hf_msdp_sa_group_addr, tvb, *offset, 4, FALSE); *offset += 4; length -= 4; proto_tree_add_item(entry_tree, hf_msdp_sa_src_addr, tvb, *offset, 4, FALSE); *offset += 4; length -= 4; } /* * Check if an encapsulated multicast IPv4 packet follows */ if (length > 0) { proto_item *ei; proto_tree *enc_tree; gint available_length, reported_length; tvbuff_t *next_tvb; ei = proto_tree_add_text(tree, tvb, *offset, length, "Encapsulated IPv4 packet: %u bytes", length); enc_tree = proto_item_add_subtree(ei, ett_msdp_sa_enc_data); available_length = tvb_length_remaining(tvb, *offset); reported_length = tvb_reported_length_remaining(tvb, *offset); g_assert(available_length >= 0); g_assert(reported_length >= 0); if (available_length > reported_length) available_length = reported_length; if (available_length > length) available_length = length; if (reported_length > length) reported_length = length; next_tvb = tvb_new_subset(tvb, *offset, available_length, reported_length); /* Set the information columns read-only so that they * reflect the MSDP packet rather than the * encapsulated packet. */ col_set_writable(pinfo->cinfo, FALSE); call_dissector(ip_handle, next_tvb, pinfo, enc_tree); } *offset += length; return; } /* Note: updates *offset */ static void add_notification_data_ipv4addr(tvbuff_t *tvb, proto_tree *tree, int *offset, const char *addrtype) { guint32 ipaddr; proto_tree_add_item(tree, hf_msdp_not_res, tvb, *offset, 3, FALSE); *offset += 3; tvb_memcpy(tvb, (guint8 *)&ipaddr, *offset, 4); proto_tree_add_ipv4_format(tree, hf_msdp_not_ipv4, tvb, *offset, 4, ipaddr, "%s: %s", addrtype, ip_to_str((guint8 *)&ipaddr)); *offset += 4; return; } static void dissect_msdp_notification(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int *offset, guint16 tlv_len) { guint8 error, error_sub; const value_string *vals; proto_tree_add_item(tree, hf_msdp_not_o, tvb, *offset, 1, FALSE); proto_tree_add_item(tree, hf_msdp_not_error, tvb, *offset, 1, FALSE); error = tvb_get_guint8(tvb, *offset); error &= 0x7F; /* Error is 7-bit field. O-bit is bit 8 */ *offset += 1; /* Depending on the Error Code, we collect the correct * value_strings for the Error subcode */ switch (error) { case MESSAGE_HEADER_ERROR: vals = hdr_error_vals; break; case SA_REQUEST_ERROR: vals = sa_req_error_vals; break; case SA_MESSAGE_SA_RESPONSE_ERROR: vals = sa_msg_error_vals; break; case FSM_ERROR: vals = fsm_error_vals; break; case HOLD_TIMER_EXPIRED: case NOTIFICATION: case CEASE: vals = sa_unspec_error_vals; break; default: vals = sa_unspec_error_vals; break; } error_sub = tvb_get_guint8(tvb, *offset); proto_tree_add_uint_format(tree, hf_msdp_not_error_sub, tvb, *offset, 1, error_sub, "Error subcode: %s (%u)", val_to_str(error_sub, vals, ""), error_sub); *offset += 1; /* Do switch again, this time to dissect the data portion * correctly. Ugly. */ switch (error) { tvbuff_t *next_tvb; case SA_REQUEST_ERROR: add_notification_data_ipv4addr(tvb, tree, offset, "Group address"); break; case SA_MESSAGE_SA_RESPONSE_ERROR: if (error_sub == 0) { break; } else if (error_sub == 1) { proto_tree_add_item(tree, hf_msdp_not_entry_count, tvb, *offset, 1, FALSE); *offset += 1; break; } else if (error_sub == 2) { add_notification_data_ipv4addr(tvb, tree, offset, "RP address"); break; } else if (error_sub == 3 || error_sub == 8) { add_notification_data_ipv4addr(tvb, tree, offset, "Group address"); break; } else if (error_sub == 4) { add_notification_data_ipv4addr(tvb, tree, offset, "Source address"); break; } else if (error_sub == 5) { proto_tree_add_item(tree, hf_msdp_not_sprefix_len, tvb, *offset, 1, FALSE); *offset += 1; break; } else if (error_sub == 6) { /* No break, causes fall through to next label */ } else if (error_sub == 7) { proto_tree_add_text(tree, tvb, *offset, tlv_len - 5, "Packet with unknown encapsulation: %u bytes", tlv_len - 5); *offset += tlv_len - 5; break; } else { proto_tree_add_text(tree, tvb, *offset, tlv_len - 5, ": %u bytes", tlv_len -5); *offset += tlv_len - 5; break; } /* Fall through */ case MESSAGE_HEADER_ERROR: case NOTIFICATION: /* Data contains the message that had an error. Even a * broken Notification message causes a Notification * message with Error Code set to Notification to be * sent back. */ next_tvb = tvb_new_subset(tvb, *offset, -1, -1); dissect_msdp(next_tvb, pinfo, tree); break; case FSM_ERROR: case HOLD_TIMER_EXPIRED: case CEASE: /* Do nothing. These contain no data */ break; default: if (tlv_len - 5 > 0) proto_tree_add_text(tree, tvb, *offset, tlv_len - 5, ": %u bytes", tlv_len -5); *offset += tlv_len - 5; break; } return; } void proto_register_msdp(void) { static hf_register_info hf[] = { { &hf_msdp_type, { "Type", "msdp.type", FT_UINT8, BASE_DEC, VALS(msdp_types), 0, "MSDP TLV type", HFILL } }, { &hf_msdp_length, { "Length", "msdp.length", FT_UINT16, BASE_DEC, NULL, 0, "MSDP TLV Length", HFILL } }, { &hf_msdp_sa_entry_count, { "Entry Count", "msdp.sa.entry_count", FT_UINT8, BASE_DEC, NULL, 0, "MSDP SA Entry Count", HFILL } }, { &hf_msdp_sa_rp_addr, { "RP Address", "msdp.sa.rp_addr", FT_IPv4, 0, NULL, 0, "Active source's RP address", HFILL } }, { &hf_msdp_sa_reserved, { "Reserved", "msdp.sa.reserved", FT_UINT24, BASE_HEX, NULL, 0, "Transmitted as zeros and ignored by a receiver", HFILL } }, { &hf_msdp_sa_sprefix_len, { "Sprefix len", "msdp.sa.sprefix_len", FT_UINT8, BASE_DEC, NULL, 0, "The route prefix length associated with source address", HFILL } }, { &hf_msdp_sa_group_addr, { "Group Address", "msdp.sa.group_addr", FT_IPv4, 0, NULL, 0, "The group address the active source has sent data to", HFILL } }, { &hf_msdp_sa_src_addr, { "Source Address", "msdp.sa.src_addr", FT_IPv4, 0, NULL, 0, "The IP address of the active source", HFILL } }, { &hf_msdp_sa_req_res, { "Reserved", "msdp.sa_req.res", FT_UINT8, BASE_HEX, NULL, 0, "Transmitted as zeros and ignored by a receiver", HFILL } }, { &hf_msdp_sa_req_group, { "Group Address", "msdp.sa_req.group_addr", FT_IPv4, 0, NULL, 0, "The group address the MSDP peer is requesting", HFILL } }, { &hf_msdp_not_o, { "Open-bit", "msdp.not.o", FT_UINT8, BASE_HEX, NULL, 0x80, "If clear, the connection will be closed", HFILL } }, { &hf_msdp_not_error, { "Error Code", "msdp.not.error", FT_UINT8, BASE_DEC, VALS(error_vals), 0x7F, "Indicates the type of Notification", HFILL } }, { &hf_msdp_not_error_sub, { "Error subode", "msdp.not.error_sub", FT_UINT8, BASE_DEC, NULL, 0, "Error subcode", HFILL } }, { &hf_msdp_not_ipv4, { "IPv4 address", "msdp.not.ipv4", FT_IPv4, 0, NULL, 0, "Group/RP/Source address in Notification messages", HFILL } }, { &hf_msdp_not_res, { "Reserved", "msdp.not.res", FT_UINT24, BASE_HEX, NULL, 0, "Reserved field in Notification messages", HFILL } }, { &hf_msdp_not_entry_count, { "Entry Count", "msdp.not.entry_count", FT_UINT24, BASE_HEX, NULL, 0, "Entry Count in Notification messages", HFILL } }, { &hf_msdp_not_sprefix_len, { "Sprefix len", "msdp.not.sprefix_len", FT_UINT8, BASE_DEC, NULL, 0, "Source prefix length in Notification messages", HFILL } }, }; static gint *ett[] = { &ett_msdp, &ett_msdp_sa_entry, &ett_msdp_sa_enc_data, &ett_msdp_not_data, }; proto_msdp = proto_register_protocol("Multicast Source Discovery Protocol", "MSDP", "msdp"); proto_register_field_array(proto_msdp, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); } void proto_reg_handoff_msdp(void) { dissector_handle_t msdp_handle; msdp_handle = create_dissector_handle(dissect_msdp, proto_msdp); dissector_add("tcp.port", 639, msdp_handle); ip_handle = find_dissector("ip"); return; }