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-rw-r--r--epan/dissectors/packet-mpls.c284
1 files changed, 284 insertions, 0 deletions
diff --git a/epan/dissectors/packet-mpls.c b/epan/dissectors/packet-mpls.c
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+++ b/epan/dissectors/packet-mpls.c
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+/* packet-mpls.c
+ * Routines for MPLS data packet disassembly
+ *
+ * (c) Copyright Ashok Narayanan <ashokn@cisco.com>
+ *
+ * $Id$
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@ethereal.com>
+ * 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 <draft-ietf-mpls-label-encaps-07.txt>
+ * Multicast MPLS support is not tested yet
+ */
+
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib.h>
+#include <epan/packet.h>
+#include "ppptypes.h"
+#include "etypes.h"
+#include "prefs.h"
+#include "packet-ppp.h"
+
+static gint proto_mpls = -1;
+
+static gint ett_mpls = -1;
+static gint ett_mpls_control = -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 int hf_mpls_control_control = -1;
+static int hf_mpls_control_res = -1;
+
+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 }},
+
+ {&hf_mpls_control_control,
+ {"MPLS Control Channel", "mpls.cw.control", FT_UINT8, BASE_DEC, NULL, 0xF0,
+ "First nibble", HFILL }},
+
+ {&hf_mpls_control_res,
+ {"Reserved", "mpls.cw.res", FT_UINT16, BASE_HEX, NULL, 0xFFF,
+ "Reserved", HFILL }},
+};
+
+static dissector_handle_t ipv4_handle;
+static dissector_handle_t ipv6_handle;
+static dissector_handle_t eth_handle;
+static dissector_handle_t data_handle;
+static dissector_table_t ppp_subdissector_table;
+
+/*
+ * 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_control(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+ proto_tree *mpls_control_tree = NULL;
+ proto_item *ti;
+ tvbuff_t *next_tvb;
+ guint8 ctrl;
+ guint16 res, ppp_proto;
+
+ if (tvb_reported_length_remaining(tvb, 0) < 4){
+ if(tree)
+ proto_tree_add_text(tree, tvb, 0, -1, "Error processing Message");
+ return;
+ }
+ ctrl = (tvb_get_guint8(tvb, 0) & 0xF0) >> 4;
+ res = tvb_get_ntohs(tvb, 0) & 0x0FFF;
+ ppp_proto = tvb_get_ntohs(tvb, 2);
+ if (tree) {
+ ti = proto_tree_add_text(tree, tvb, 0, 4, "MPLS PW Control Channel Header");
+ mpls_control_tree = proto_item_add_subtree(ti, ett_mpls_control);
+ if(mpls_control_tree == NULL) return;
+
+ proto_tree_add_uint_format(mpls_control_tree, hf_mpls_control_control, tvb, 0, 1,
+ ctrl, "Control Channel: 0x%1x", ctrl);
+ proto_tree_add_uint_format(mpls_control_tree, hf_mpls_control_res, tvb, 0, 2,
+ res, "Reserved: 0x%03x", res);
+ proto_tree_add_text(mpls_control_tree, tvb, 2, 2,
+ "PPP DLL Protocol Number: %s (0x%04X)",
+ val_to_str(ppp_proto, ppp_vals, "Unknown"), ppp_proto);
+ }
+ next_tvb = tvb_new_subset(tvb, 4, -1, -1);
+ if (!dissector_try_port(ppp_subdissector_table, ppp_proto,
+ next_tvb, pinfo, tree)) {
+ call_dissector(data_handle, next_tvb, pinfo, tree);
+ }
+
+
+}
+
+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 if (ipvers == 1) {
+ dissect_mpls_control(next_tvb, pinfo, tree);
+ } else {
+ call_dissector(eth_handle, next_tvb, pinfo, tree);
+ }
+}
+
+void
+proto_register_mpls(void)
+{
+ static gint *ett[] = {
+ &ett_mpls,
+ &ett_mpls_control,
+ };
+
+ 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 and PPP protocol dissector table.
+ */
+ ipv4_handle = find_dissector("ip");
+ ipv6_handle = find_dissector("ipv6");
+ eth_handle = find_dissector("eth");
+ data_handle = find_dissector("data");
+ ppp_subdissector_table = find_dissector_table("ppp.protocol");
+
+
+ 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);
+ dissector_add("gre.proto", ETHERTYPE_MPLS, mpls_handle);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-19 11:19:32 +0000