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

1 files changed, 193 insertions, 0 deletions

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 <ashokn@cisco.com>
+ *
+ * $Id: packet-mpls.c,v 1.1 2000/03/09 18:31:50 ashokn Exp $
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@zing.org>
+ * 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
+
+#ifdef HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+
+#include <glib.h>
+#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));
+}
+