From 519161968a99f0b6a73b76f1cbcf87d29533c580 Mon Sep 17 00:00:00 2001 From: Ashok Narayanan Date: Thu, 9 Mar 2000 18:31:51 +0000 Subject: Support for MultiProtocol Label Switching (MPLS). The following support is being added - MPLS Traffic Engineering extensions for RSVP - MPLS-encapsulated IP packets on Ethernet - OSPF Extensions for MPLS (including generic opaque LSA support for OSPF) THe following features will be committed at a later date (if I get around to writing them :-) - Label Distribution Protocol (LDP) - IS-IS Extensions for MPLS svn path=/trunk/; revision=1707 --- packet-mpls.c | 193 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 packet-mpls.c (limited to 'packet-mpls.c') diff --git a/packet-mpls.c b/packet-mpls.c new file mode 100644 index 0000000000..88825cdcfc --- /dev/null +++ b/packet-mpls.c @@ -0,0 +1,193 @@ +/* packet-mpls.c + * Routines for MPLS data packet disassembly + * + * (c) Copyright Ashok Narayanan + * + * $Id: packet-mpls.c,v 1.1 2000/03/09 18:31:50 ashokn 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 + +#ifdef HAVE_SYS_TYPES_H +# include +#endif + +#include +#include "packet.h" +#include "packet-mpls.h" +#include "packet-ip.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_NONE, NULL, 0x0, + "" }}, + + {&mpls_filter[MPLSF_LABEL], + {"MPLS Label", "mpls.label", FT_UINT32, BASE_NONE, NULL, 0x0, + "" }}, + + {&mpls_filter[MPLSF_EXP], + {"MPLS Experimental Bits", "mpls.exp", FT_UINT8, BASE_NONE, NULL, 0x0, + "" }}, + + {&mpls_filter[MPLSF_BOTTOM_OF_STACK], + {"MPLS Bottom Of Label Stack", "mpls.bottom", FT_UINT8, BASE_NONE, NULL, 0x0, + "" }}, + + {&mpls_filter[MPLSF_TTL], + {"MPLS TTL", "mpls.ttl", FT_UINT8, BASE_NONE, NULL, 0x0, + "" }}, +}; + +/* + * Given a 4-byte MPLS label starting at "start", decode this. + * Return the label in "label", EXP bits in "exp", + * bottom_of_stack in "bos", and TTL in "ttl" + */ +void decode_mpls_label(const unsigned char *start, + guint32 *label, guint8 *exp, + guint8 *bos, guint8 *ttl) +{ + *label = (start[0] << 12) + (start[1] << 4) + ((start[2] >> 4) & 0xff); + *exp = (start[2] >> 1) & 0x7; + *bos = (start[2] & 0x1); + *ttl = start[3]; +} + +void +dissect_mpls(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) +{ + guint32 label; + guint8 exp; + guint8 bos; + guint8 ttl; + + proto_tree *mpls_tree; + proto_item *ti; + + if (check_col(fd, COL_PROTOCOL)) { + col_add_str(fd,COL_PROTOCOL, "MPLS"); + } + + if (check_col(fd,COL_INFO)) { + col_add_fstr(fd,COL_INFO,"MPLS Label Switched Packet"); + } + + /* Start Decoding Here. */ + while (1) { + if (!BYTES_ARE_IN_FRAME(offset, 4)) { + dissect_data(pd, offset, fd, tree); + return; + } + + decode_mpls_label(pd+offset, &label, &exp, &bos, &ttl); + + if (tree) { + + ti = proto_tree_add_item(tree, proto_mpls, offset, 4, NULL); + mpls_tree = proto_item_add_subtree(ti, ett_mpls); + + if (label <= MAX_RESERVED) + proto_tree_add_text(mpls_tree, offset, 3, + "Label: %d (%s)", + label, val_to_str(label, special_labels, + "Reserved - Unknown")); + else + proto_tree_add_text(mpls_tree, offset, 3, + "Label: %d", label); + proto_tree_add_item_hidden(mpls_tree, mpls_filter[MPLSF_LABEL], + offset,3, label); + proto_tree_add_item(mpls_tree,mpls_filter[MPLSF_EXP], + offset+2,1, exp); + proto_tree_add_item(mpls_tree,mpls_filter[MPLSF_BOTTOM_OF_STACK], + offset+2,1, bos); + proto_tree_add_item(mpls_tree,mpls_filter[MPLSF_TTL], + offset+3,1, ttl); + } + offset += 4; + if (bos) break; + } + dissect_ip(pd, offset, fd, tree); +} + +void +proto_register_mpls(void) +{ + static gint *ett[] = { + &ett_mpls, + }; + + proto_mpls = proto_register_protocol("MultiProtocol Label Switching Header", "mpls"); + proto_register_field_array(proto_mpls, mplsf_info, array_length(mplsf_info)); + proto_register_subtree_array(ett, array_length(ett)); +} + -- cgit v1.2.3