/* packet-mpls.c * Routines for MPLS data packet disassembly * * (c) Copyright Ashok Narayanan * * $Id: packet-mpls.c,v 1.29 2003/01/27 19:28:52 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. */ /* * NOTES * * This module defines routines to handle Ethernet-encapsulated MPLS IP packets. * It should implement all the functionality in * Multicast MPLS support is not tested yet */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include "ppptypes.h" #include "etypes.h" static gint proto_mpls = -1; static gint ett_mpls = -1; /* Special labels in MPLS */ enum { IP4_EXPLICIT_NULL = 0, ROUTER_ALERT, IP6_EXPLICIT_NULL, IMPLICIT_NULL, MAX_RESERVED = 15 }; static const value_string special_labels[] = { {IP4_EXPLICIT_NULL, "IPv4 Explicit-Null"}, {ROUTER_ALERT, "Router Alert"}, {IP6_EXPLICIT_NULL, "IPv6 Explicit-Null"}, {IMPLICIT_NULL, "Implicit-Null"}, {0, NULL } }; /* MPLS filter values */ enum mpls_filter_keys { /* Is the packet MPLS-encapsulated? */ /* MPLSF_PACKET,*/ /* MPLS encap properties */ MPLSF_LABEL, MPLSF_EXP, MPLSF_BOTTOM_OF_STACK, MPLSF_TTL, MPLSF_MAX }; static int mpls_filter[MPLSF_MAX]; static hf_register_info mplsf_info[] = { /* {&mpls_filter[MPLSF_PACKET], {"MPLS Label Switched Packet", "mpls", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }},*/ {&mpls_filter[MPLSF_LABEL], {"MPLS Label", "mpls.label", FT_UINT32, BASE_DEC, VALS(special_labels), 0x0, "", HFILL }}, {&mpls_filter[MPLSF_EXP], {"MPLS Experimental Bits", "mpls.exp", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, {&mpls_filter[MPLSF_BOTTOM_OF_STACK], {"MPLS Bottom Of Label Stack", "mpls.bottom", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, {&mpls_filter[MPLSF_TTL], {"MPLS TTL", "mpls.ttl", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, }; static dissector_handle_t ipv4_handle; static dissector_handle_t ipv6_handle; static dissector_handle_t eth_handle; /* * Given a 4-byte MPLS label starting at offset "offset", in tvbuff "tvb", * decode it. * Return the label in "label", EXP bits in "exp", * bottom_of_stack in "bos", and TTL in "ttl" */ void decode_mpls_label(tvbuff_t *tvb, int offset, guint32 *label, guint8 *exp, guint8 *bos, guint8 *ttl) { guint8 octet0 = tvb_get_guint8(tvb, offset+0); guint8 octet1 = tvb_get_guint8(tvb, offset+1); guint8 octet2 = tvb_get_guint8(tvb, offset+2); *label = (octet0 << 12) + (octet1 << 4) + ((octet2 >> 4) & 0xff); *exp = (octet2 >> 1) & 0x7; *bos = (octet2 & 0x1); *ttl = tvb_get_guint8(tvb, offset+3); } static void dissect_mpls(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { int offset = 0; guint32 label; guint8 exp; guint8 bos; guint8 ttl; guint8 ipvers; proto_tree *mpls_tree; proto_item *ti; tvbuff_t *next_tvb; if (check_col(pinfo->cinfo, COL_PROTOCOL)) { col_set_str(pinfo->cinfo,COL_PROTOCOL, "MPLS"); } if (check_col(pinfo->cinfo,COL_INFO)) { col_add_fstr(pinfo->cinfo,COL_INFO,"MPLS Label Switched Packet"); } /* Start Decoding Here. */ while (tvb_reported_length_remaining(tvb, offset) > 0) { decode_mpls_label(tvb, offset, &label, &exp, &bos, &ttl); if (tree) { ti = proto_tree_add_item(tree, proto_mpls, tvb, offset, 4, FALSE); mpls_tree = proto_item_add_subtree(ti, ett_mpls); if (label <= MAX_RESERVED) proto_tree_add_uint_format(mpls_tree, mpls_filter[MPLSF_LABEL], tvb, offset, 3, label, "Label: %u (%s)", label, val_to_str(label, special_labels, "Reserved - Unknown")); else proto_tree_add_uint(mpls_tree, mpls_filter[MPLSF_LABEL], tvb, offset, 3, label); proto_tree_add_uint(mpls_tree,mpls_filter[MPLSF_EXP], tvb, offset+2,1, exp); proto_tree_add_uint(mpls_tree,mpls_filter[MPLSF_BOTTOM_OF_STACK], tvb, offset+2,1, bos); proto_tree_add_uint(mpls_tree,mpls_filter[MPLSF_TTL], tvb, offset+3,1, ttl); } offset += 4; if (bos) break; } next_tvb = tvb_new_subset(tvb, offset, -1, -1); ipvers = (tvb_get_guint8(tvb, offset) >> 4) & 0x0F; if (ipvers == 6) { call_dissector(ipv6_handle, next_tvb, pinfo, tree); } else if (ipvers == 4) { call_dissector(ipv4_handle, next_tvb, pinfo, tree); } else { call_dissector(eth_handle, next_tvb, pinfo, tree); } } void proto_register_mpls(void) { static gint *ett[] = { &ett_mpls, }; proto_mpls = proto_register_protocol("MultiProtocol Label Switching Header", "MPLS", "mpls"); proto_register_field_array(proto_mpls, mplsf_info, array_length(mplsf_info)); proto_register_subtree_array(ett, array_length(ett)); } void proto_reg_handoff_mpls(void) { dissector_handle_t mpls_handle; /* * Get a handle for the IPv4 and IPv6 dissectors. */ ipv4_handle = find_dissector("ip"); ipv6_handle = find_dissector("ipv6"); eth_handle = find_dissector("eth"); mpls_handle = create_dissector_handle(dissect_mpls, proto_mpls); dissector_add("ethertype", ETHERTYPE_MPLS, mpls_handle); dissector_add("ppp.protocol", PPP_MPLS_UNI, mpls_handle); dissector_add("chdlctype", ETHERTYPE_MPLS, mpls_handle); dissector_add("chdlctype", ETHERTYPE_MPLS_MULTI, mpls_handle); }