Split packet-ip into packet-ip and packet-icmp.

Some cleanup in handles and ett entries.

svn path=/trunk/; revision=29035

1 files changed, 1100 insertions, 0 deletions

diff --git a/epan/dissectors/packet-icmp.c b/epan/dissectors/packet-icmp.c
new file mode 100644
index 0000000000..852133d40d
--- /dev/null
+++ b/epan/dissectors/packet-icmp.c
@@ -0,0 +1,1100 @@
+/* packet-icmp.c
+ * Routines for ICMP - Internet Control Message Protocol
+ *
+ * $Id$
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * Monday, June 27, 2005
+ * Support for the ICMP extensions for MPLS
+ * (http://www.ietf.org/proceedings/01aug/I-D/draft-ietf-mpls-icmp-02.txt)
+ * by   Maria-Luiza Crivat <luizacri@gmail.com>
+ * &    Brice Augustin <bricecotte@gmail.com>
+ *
+ * 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 <stdio.h>
+#include <string.h>
+#include <glib.h>
+
+#include <epan/packet.h>
+#include <epan/ipproto.h>
+#include <epan/prefs.h>
+#include <epan/in_cksum.h>
+
+#include "packet-ip.h"
+
+
+/* Decode the end of the ICMP payload as ICMP MPLS extensions
+if the packet in the payload has more than 128 bytes */
+static gboolean favor_icmp_mpls_ext = FALSE;
+
+static int proto_icmp = -1;
+static int hf_icmp_type = -1;
+static int hf_icmp_code = -1;
+static int hf_icmp_checksum = -1;
+static int hf_icmp_checksum_bad = -1;
+static int hf_icmp_ident = -1;
+static int hf_icmp_seq_num = -1;
+static int hf_icmp_mtu = -1;
+static int hf_icmp_redir_gw = -1;
+
+
+/* Mobile ip */
+static int hf_icmp_mip_type = -1;
+static int hf_icmp_mip_length = -1;
+static int hf_icmp_mip_prefix_length = -1;
+static int hf_icmp_mip_seq = -1;
+static int hf_icmp_mip_life = -1;
+static int hf_icmp_mip_flags = -1;
+static int hf_icmp_mip_r = -1;
+static int hf_icmp_mip_b = -1;
+static int hf_icmp_mip_h = -1;
+static int hf_icmp_mip_f = -1;
+static int hf_icmp_mip_m = -1;
+static int hf_icmp_mip_g = -1;
+static int hf_icmp_mip_v = -1;
+static int hf_icmp_mip_rt = -1;
+static int hf_icmp_mip_u = -1;
+static int hf_icmp_mip_x = -1;
+static int hf_icmp_mip_reserved = -1;
+static int hf_icmp_mip_coa = -1;
+static int hf_icmp_mip_challenge = -1;
+
+/* MPLS extensions */
+static int hf_icmp_mpls = -1;
+static int hf_icmp_mpls_version = -1;
+static int hf_icmp_mpls_reserved = -1;
+static int hf_icmp_mpls_checksum = -1;
+static int hf_icmp_mpls_checksum_bad = -1;
+static int hf_icmp_mpls_length = -1;
+static int hf_icmp_mpls_class = -1;
+static int hf_icmp_mpls_c_type = -1;
+static int hf_icmp_mpls_label = -1;
+static int hf_icmp_mpls_exp = -1;
+static int hf_icmp_mpls_s = -1;
+static int hf_icmp_mpls_ttl = -1;
+
+static gint ett_icmp = -1;
+static gint ett_icmp_mip = -1;
+static gint ett_icmp_mip_flags = -1;
+
+/* MPLS extensions */
+static gint ett_icmp_mpls = -1;
+static gint ett_icmp_mpls_object = -1;
+static gint ett_icmp_mpls_stack_object = -1;
+
+/* ICMP definitions */
+
+#define ICMP_ECHOREPLY     0
+#define ICMP_UNREACH       3
+#define ICMP_SOURCEQUENCH  4
+#define ICMP_REDIRECT      5
+#define ICMP_ECHO          8
+#define ICMP_RTRADVERT     9
+#define ICMP_RTRSOLICIT   10
+#define ICMP_TIMXCEED     11
+#define ICMP_PARAMPROB    12
+#define ICMP_TSTAMP       13
+#define ICMP_TSTAMPREPLY  14
+#define ICMP_IREQ         15
+#define ICMP_IREQREPLY    16
+#define ICMP_MASKREQ      17
+#define ICMP_MASKREPLY    18
+
+/* ICMP UNREACHABLE */
+
+#define ICMP_NET_UNREACH        0       /* Network Unreachable */
+#define ICMP_HOST_UNREACH       1       /* Host Unreachable */
+#define ICMP_PROT_UNREACH       2       /* Protocol Unreachable */
+#define ICMP_PORT_UNREACH       3       /* Port Unreachable */
+#define ICMP_FRAG_NEEDED        4       /* Fragmentation Needed/DF set */
+#define ICMP_SR_FAILED          5       /* Source Route failed */
+#define ICMP_NET_UNKNOWN        6
+#define ICMP_HOST_UNKNOWN       7
+#define ICMP_HOST_ISOLATED      8
+#define ICMP_NET_ANO            9
+#define ICMP_HOST_ANO           10
+#define ICMP_NET_UNR_TOS        11
+#define ICMP_HOST_UNR_TOS       12
+#define ICMP_PKT_FILTERED       13      /* Packet filtered */
+#define ICMP_PREC_VIOLATION     14      /* Precedence violation */
+#define ICMP_PREC_CUTOFF        15      /* Precedence cut off */
+
+#define ICMP_MIP_EXTENSION_PAD	0
+#define ICMP_MIP_MOB_AGENT_ADV	16
+#define ICMP_MIP_PREFIX_LENGTHS	19
+#define ICMP_MIP_CHALLENGE	24
+
+static dissector_handle_t ip_handle;
+static dissector_handle_t data_handle;
+
+static const value_string mip_extensions[] = {
+  { ICMP_MIP_EXTENSION_PAD, "One byte padding extension"},  /* RFC 2002 */
+  { ICMP_MIP_MOB_AGENT_ADV, "Mobility Agent Advertisement Extension"},
+							    /* RFC 2002 */
+  { ICMP_MIP_PREFIX_LENGTHS, "Prefix Lengths Extension"},   /* RFC 2002 */
+  { ICMP_MIP_CHALLENGE, "Challenge Extension"},             /* RFC 3012 */
+  { 0, NULL}
+};
+
+/*
+ * Dissect the mobile ip advertisement extensions.
+ */
+static void
+dissect_mip_extensions(tvbuff_t *tvb, int offset, proto_tree *tree)
+{
+  guint8       type;
+  guint8       length;
+  guint16      flags;
+  proto_item   *ti;
+  proto_tree   *mip_tree=NULL;
+  proto_tree   *flags_tree=NULL;
+  gint         numCOAs;
+  gint         i;
+
+  /* Not much to do if we're not parsing everything */
+  if (!tree) return;
+
+  while (tvb_reported_length_remaining(tvb, offset) > 0) {
+
+	type = tvb_get_guint8(tvb, offset + 0);
+	if (type)
+	  length = tvb_get_guint8(tvb, offset + 1);
+	else
+	  length=0;
+
+	ti = proto_tree_add_text(tree, tvb, offset,
+							 type?(length + 2):1,
+							 "Ext: %s",
+							 val_to_str(type, mip_extensions,
+										"Unknown ext %u"));
+	mip_tree = proto_item_add_subtree(ti, ett_icmp_mip);
+
+
+	switch (type) {
+	case ICMP_MIP_EXTENSION_PAD:
+	  /* One byte padding extension */
+	  /* Add our fields */
+	  /* type */
+	  proto_tree_add_item(mip_tree, hf_icmp_mip_type, tvb, offset,
+						  1, FALSE);
+	  offset++;
+	  break;
+	case ICMP_MIP_MOB_AGENT_ADV:
+	  /* Mobility Agent Advertisement Extension (RFC 2002)*/
+	  /* Add our fields */
+	  /* type */
+	  proto_tree_add_item(mip_tree, hf_icmp_mip_type, tvb, offset,
+						  1, FALSE);
+	  offset++;
+	  /* length */
+	  proto_tree_add_item(mip_tree, hf_icmp_mip_length, tvb, offset,
+						  1, FALSE);
+	  offset++;
+	  /* sequence number */
+	  proto_tree_add_item(mip_tree, hf_icmp_mip_seq, tvb, offset,
+						  2, FALSE);
+	  offset+=2;
+	  /* Registration Lifetime */
+	  proto_tree_add_item(mip_tree, hf_icmp_mip_life, tvb, offset,
+						  2, FALSE);
+	  offset+=2;
+	  /* flags */
+	  flags = tvb_get_ntohs(tvb, offset);
+	  ti = proto_tree_add_uint(mip_tree, hf_icmp_mip_flags, tvb, offset, 2, flags);
+	  flags_tree = proto_item_add_subtree(ti, ett_icmp_mip_flags);
+	  proto_tree_add_boolean(flags_tree, hf_icmp_mip_r, tvb, offset, 2, flags);
+	  proto_tree_add_boolean(flags_tree, hf_icmp_mip_b, tvb, offset, 2, flags);
+	  proto_tree_add_boolean(flags_tree, hf_icmp_mip_h, tvb, offset, 2, flags);
+	  proto_tree_add_boolean(flags_tree, hf_icmp_mip_f, tvb, offset, 2, flags);
+	  proto_tree_add_boolean(flags_tree, hf_icmp_mip_m, tvb, offset, 2, flags);
+	  proto_tree_add_boolean(flags_tree, hf_icmp_mip_g, tvb, offset, 2, flags);
+	  proto_tree_add_boolean(flags_tree, hf_icmp_mip_v, tvb, offset, 2, flags);
+	  proto_tree_add_boolean(flags_tree, hf_icmp_mip_rt, tvb, offset, 2, flags);
+	  proto_tree_add_boolean(flags_tree, hf_icmp_mip_u, tvb, offset, 2, flags);
+	  proto_tree_add_boolean(flags_tree, hf_icmp_mip_x, tvb, offset, 2, flags);
+
+	  /* Reserved */
+	  proto_tree_add_uint(flags_tree, hf_icmp_mip_reserved, tvb, offset, 2, flags);
+	  offset+=2;
+
+	  /* COAs */
+	  numCOAs = (length - 6) / 4;
+	  for (i=0; i<numCOAs; i++) {
+		proto_tree_add_item(mip_tree, hf_icmp_mip_coa, tvb, offset,
+							4, FALSE);
+		offset+=4;
+	  }
+	  break;
+	case ICMP_MIP_PREFIX_LENGTHS:
+	  /* Prefix-Lengths Extension  (RFC 2002)*/
+	  /* Add our fields */
+	  /* type */
+	  proto_tree_add_item(mip_tree, hf_icmp_mip_type, tvb, offset,
+						  1, FALSE);
+	  offset++;
+	  /* length */
+	  proto_tree_add_item(mip_tree, hf_icmp_mip_length, tvb, offset,
+						  1, FALSE);
+	  offset++;
+
+	  /* prefix lengths */
+	  for(i=0; i<length; i++) {
+		proto_tree_add_item(mip_tree, hf_icmp_mip_prefix_length, tvb, offset,
+							1, FALSE);
+		offset++;
+	  }
+	  break;
+	case ICMP_MIP_CHALLENGE:
+	  /* Challenge Extension  (RFC 3012)*/
+	  /* type */
+	  proto_tree_add_item(mip_tree, hf_icmp_mip_type, tvb, offset,
+						  1, FALSE);
+	  offset++;
+	  /* length */
+	  proto_tree_add_item(mip_tree, hf_icmp_mip_length, tvb, offset,
+						  1, FALSE);
+	  offset++;
+	  /* challenge */
+	  proto_tree_add_item(mip_tree, hf_icmp_mip_challenge, tvb, offset,
+						  length, FALSE);
+	  offset+=length;
+
+	  break;
+	default:
+	  g_warning("Unknown type(%u)!  I hope the length is right (%u)",
+				type, length);
+	  offset += length + 2;
+	  break;
+	} /* switch type */
+  } /* end while */
+
+} /* dissect_mip_extensions */
+
+#define MPLS_STACK_ENTRY_OBJECT_CLASS           1
+#define MPLS_EXTENDED_PAYLOAD_OBJECT_CLASS      2
+
+#define MPLS_STACK_ENTRY_C_TYPE                 1
+#define MPLS_EXTENDED_PAYLOAD_C_TYPE            1
+
+/* XXX no header defines these macros ??? */
+#ifndef min
+#define min(a,b) (((a)<(b))?(a):(b))
+#endif
+
+#ifndef max
+#define max(a,b) (((a)>(b))?(a):(b))
+#endif
+
+/*
+ * Dissect the MPLS extensions
+ */
+static void
+dissect_mpls_extensions(tvbuff_t *tvb, gint offset, proto_tree *tree)
+{
+    guint8          version;
+    guint8          class_num;
+    guint8          c_type;
+    guint8          ttl;
+    guint8          tmp;
+    guint16         reserved;
+    guint16         cksum, computed_cksum;
+    guint16         obj_length, obj_trunc_length;
+    proto_item      *ti, *tf_object, *tf_entry, *hidden_item;
+    proto_tree      *mpls_tree=NULL, *mpls_object_tree, *mpls_stack_object_tree;
+    gint            obj_end_offset;
+    guint           reported_length;
+    guint           label;
+    gboolean        unknown_object;
+
+    if (!tree)
+        return;
+
+    reported_length = tvb_reported_length_remaining(tvb, offset);
+
+    if (reported_length < 4 /* Common header */)
+    {
+        proto_tree_add_text(tree, tvb, offset,
+                            reported_length,
+                            "MPLS Extensions (truncated)");
+        return;
+    }
+
+    /* Add a tree for the MPLS extensions */
+    ti = proto_tree_add_none_format(tree, hf_icmp_mpls, tvb,
+                                            offset, reported_length, "MPLS Extensions");
+
+    mpls_tree = proto_item_add_subtree(ti, ett_icmp_mpls);
+
+    /* Version */
+    version = hi_nibble(tvb_get_guint8(tvb, offset));
+    proto_tree_add_uint(mpls_tree, hf_icmp_mpls_version, tvb, offset, 1, version);
+
+    /* Reserved */
+    reserved = tvb_get_ntohs(tvb, offset) & 0x0fff;
+    proto_tree_add_uint_format(mpls_tree, hf_icmp_mpls_reserved,
+                                tvb, offset, 2, reserved,
+                                "Reserved: 0x%03x", reserved);
+
+    /* Checksum */
+    cksum = tvb_get_ntohs(tvb, offset + 2);
+
+    computed_cksum = ip_checksum(tvb_get_ptr(tvb, offset, reported_length),
+                                    reported_length);
+
+    if (computed_cksum == 0)
+    {
+        proto_tree_add_uint_format(mpls_tree, hf_icmp_mpls_checksum, tvb, offset + 2, 2,
+                                    cksum, "Checksum: 0x%04x [correct]", cksum);
+    }
+    else
+    {
+        hidden_item = proto_tree_add_boolean(mpls_tree, hf_icmp_mpls_checksum_bad, tvb,
+                                            offset + 2, 2, TRUE);
+        PROTO_ITEM_SET_HIDDEN(hidden_item);
+
+        proto_tree_add_uint_format(mpls_tree, hf_icmp_mpls_checksum, tvb, offset + 2, 2,
+                                    cksum,
+                                    "Checksum: 0x%04x [incorrect, should be 0x%04x]",
+                                    cksum, in_cksum_shouldbe(cksum, computed_cksum));
+    }
+
+    if (version != 1 && version != 2)
+    {
+        /* Unsupported version */
+        proto_item_append_text(ti, " (unsupported version)");
+        return;
+    }
+
+    /* Skip the common header */
+    offset += 4;
+
+    /* While there is enough room to read an object */
+    while (tvb_reported_length_remaining(tvb, offset) >= 4 /* Object header */)
+    {
+        /* Object length */
+        obj_length = tvb_get_ntohs(tvb, offset);
+
+        obj_trunc_length =  min(obj_length, tvb_reported_length_remaining(tvb, offset));
+
+        obj_end_offset = offset + obj_trunc_length;
+
+        /* Add a subtree for this object (the text will be reset later) */
+        tf_object = proto_tree_add_text(mpls_tree, tvb, offset,
+                                        max(obj_trunc_length, 4),
+                                        "Unknown object");
+
+        mpls_object_tree = proto_item_add_subtree(tf_object, ett_icmp_mpls_object);
+
+        proto_tree_add_uint(mpls_object_tree, hf_icmp_mpls_length, tvb, offset, 2, obj_length);
+
+        /* Class */
+        class_num = tvb_get_guint8(tvb, offset + 2);
+        proto_tree_add_uint(mpls_object_tree, hf_icmp_mpls_class, tvb, offset + 2, 1, class_num);
+
+        /* C-Type */
+        c_type = tvb_get_guint8(tvb, offset + 3);
+        proto_tree_add_uint(mpls_object_tree, hf_icmp_mpls_c_type, tvb, offset + 3, 1, c_type);
+
+        if (obj_length < 4 /* Object header */)
+        {
+            /* Thanks doc/README.developer :)) */
+            proto_item_set_text(tf_object, "Object with bad length");
+            break;
+        }
+
+        /* Skip the object header */
+        offset += 4;
+
+        /* Default cases will set this flag to TRUE */
+        unknown_object = FALSE;
+
+        switch (class_num)
+        {
+            case MPLS_STACK_ENTRY_OBJECT_CLASS:
+                switch (c_type)
+                {
+                    case MPLS_STACK_ENTRY_C_TYPE:
+
+                        proto_item_set_text(tf_object, "MPLS Stack Entry");
+
+                        /* For each entry */
+                        while (offset + 4 <= obj_end_offset)
+                        {
+                            if (tvb_reported_length_remaining(tvb, offset) < 4)
+                            {
+                                /* Not enough room in the packet ! */
+                                break;
+                            }
+
+                            /* Create a subtree for each entry (the text will be set later) */
+                            tf_entry = proto_tree_add_text(mpls_object_tree,
+                                                            tvb, offset, 4, " ");
+                            mpls_stack_object_tree = proto_item_add_subtree(tf_entry,
+                                                                            ett_icmp_mpls_stack_object);
+
+                            /* Label */
+                            label =  (guint)tvb_get_ntohs(tvb, offset);
+                            tmp = tvb_get_guint8(tvb, offset + 2);
+                            label = (label << 4) + (tmp >> 4);
+
+                            proto_tree_add_uint(mpls_stack_object_tree,
+                                                    hf_icmp_mpls_label,
+                                                    tvb,
+                                                    offset,
+                                                    3,
+                                                    label << 4);
+
+                            proto_item_set_text(tf_entry, "Label: %u", label);
+
+                            /* Experimental field (also called "CoS") */
+                            proto_tree_add_uint(mpls_stack_object_tree,
+                                                    hf_icmp_mpls_exp,
+                                                    tvb,
+                                                    offset + 2,
+                                                    1,
+                                                    tmp);
+
+                            proto_item_append_text(tf_entry, ", Exp: %u", (tmp >> 1) & 0x07);
+
+                            /* Stack bit */
+                            proto_tree_add_boolean(mpls_stack_object_tree,
+                                                    hf_icmp_mpls_s,
+                                                    tvb,
+                                                    offset + 2,
+                                                    1,
+                                                    tmp);
+
+                            proto_item_append_text(tf_entry, ", S: %u", tmp  & 0x01);
+
+                            /* TTL */
+                            ttl = tvb_get_guint8(tvb, offset + 3);
+
+                            proto_tree_add_item(mpls_stack_object_tree,
+                                                hf_icmp_mpls_ttl,
+                                                tvb,
+                                                offset + 3,
+                                                1,
+                                                FALSE);
+
+                            proto_item_append_text(tf_entry, ", TTL: %u", ttl);
+
+                            /* Skip the entry */
+                            offset += 4;
+
+                        } /* end while */
+
+                        if (offset < obj_end_offset)
+                            proto_tree_add_text(mpls_object_tree, tvb,
+                                                offset,
+                                                obj_end_offset - offset,
+                                                "%d junk bytes",
+                                                obj_end_offset - offset);
+
+                        break;
+                    default:
+
+                        unknown_object = TRUE;
+
+                        break;
+                } /* end switch c_type */
+                break;
+            case MPLS_EXTENDED_PAYLOAD_OBJECT_CLASS:
+                switch (c_type)
+                {
+                    case MPLS_EXTENDED_PAYLOAD_C_TYPE:
+                        proto_item_set_text(tf_object, "Extended Payload");
+
+                        /* This object contains some portion of the original packet
+                        that could not fit in the 128 bytes of the ICMP payload */
+                        if (obj_trunc_length > 4)
+                            proto_tree_add_text(mpls_object_tree, tvb,
+                                                offset, obj_trunc_length - 4,
+                                                "Data (%d bytes)", obj_trunc_length - 4);
+
+                        break;
+                    default:
+
+                        unknown_object = TRUE;
+
+                        break;
+                } /* end switch c_type */
+                break;
+            default:
+
+                unknown_object = TRUE;
+
+                break;
+        } /* end switch class_num */
+
+        /* The switches couldn't decode the object */
+        if (unknown_object == TRUE)
+        {
+            proto_item_set_text(tf_object, "Unknown object (%d/%d)", class_num, c_type);
+
+            if (obj_trunc_length > 4)
+                proto_tree_add_text(mpls_object_tree, tvb,
+                                    offset, obj_trunc_length - 4,
+                                    "Data (%d bytes)", obj_trunc_length - 4);
+        }
+
+        /* */
+        if (obj_trunc_length < obj_length)
+            proto_item_append_text(tf_object, " (truncated)");
+
+        /* Go to the end of the object */
+        offset = obj_end_offset;
+
+    } /* end while */
+} /* end dissect_mpls_extensions */
+
+static const gchar *unreach_str[] = {"Network unreachable",
+                                     "Host unreachable",
+                                     "Protocol unreachable",
+                                     "Port unreachable",
+                                     "Fragmentation needed",
+                                     "Source route failed",
+                                     "Destination network unknown",
+                                     "Destination host unknown",
+                                     "Source host isolated",
+                                     "Network administratively prohibited",
+                                     "Host administratively prohibited",
+                                     "Network unreachable for TOS",
+                                     "Host unreachable for TOS",
+                                     "Communication administratively filtered",
+                                     "Host precedence violation",
+                                     "Precedence cutoff in effect"};
+
+#define	N_UNREACH	(sizeof unreach_str / sizeof unreach_str[0])
+
+static const gchar *redir_str[] = {"Redirect for network",
+                                   "Redirect for host",
+                                   "Redirect for TOS and network",
+                                   "Redirect for TOS and host"};
+
+#define	N_REDIRECT	(sizeof redir_str / sizeof redir_str[0])
+
+static const gchar *ttl_str[] = {"Time to live exceeded in transit",
+                                 "Fragment reassembly time exceeded"};
+
+#define	N_TIMXCEED	(sizeof ttl_str / sizeof ttl_str[0])
+
+static const gchar *par_str[] = {"IP header bad", "Required option missing"};
+
+#define	N_PARAMPROB	(sizeof par_str / sizeof par_str[0])
+
+/*
+ * RFC 792 for basic ICMP.
+ * RFC 1191 for ICMP_FRAG_NEEDED (with MTU of next hop).
+ * RFC 1256 for router discovery messages.
+ * RFC 2002 and 3012 for Mobile IP stuff.
+ */
+static void
+dissect_icmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+  proto_tree *icmp_tree = NULL;
+  guint8     icmp_type;
+  guint8     icmp_code;
+  guint      length, reported_length;
+  guint16    cksum, computed_cksum;
+  const gchar *type_str, *code_str;
+  guint8     num_addrs = 0;
+  guint8     addr_entry_size = 0;
+  int        i;
+  gboolean   save_in_error_pkt;
+  tvbuff_t   *next_tvb;
+  proto_item *item;
+
+  type_str="";
+  code_str="";
+
+
+  if (check_col(pinfo->cinfo, COL_PROTOCOL))
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "ICMP");
+  if (check_col(pinfo->cinfo, COL_INFO))
+    col_clear(pinfo->cinfo, COL_INFO);
+
+  /* To do: check for runts, errs, etc. */
+  icmp_type = tvb_get_guint8(tvb, 0);
+  icmp_code = tvb_get_guint8(tvb, 1);
+  cksum = tvb_get_ntohs(tvb, 2);
+
+  switch (icmp_type) {
+    case ICMP_ECHOREPLY:
+      type_str="Echo (ping) reply";
+      break;
+    case ICMP_UNREACH:
+      type_str="Destination unreachable";
+      if (icmp_code < N_UNREACH) {
+        code_str = unreach_str[icmp_code];
+      } else {
+        code_str = "Unknown - error?";
+      }
+      break;
+    case ICMP_SOURCEQUENCH:
+      type_str="Source quench (flow control)";
+      break;
+    case ICMP_REDIRECT:
+      type_str="Redirect";
+      if (icmp_code < N_REDIRECT) {
+        code_str = redir_str[icmp_code];
+      } else {
+        code_str = "Unknown - error?";
+      }
+      break;
+    case ICMP_ECHO:
+      type_str="Echo (ping) request";
+      break;
+    case ICMP_RTRADVERT:
+      switch (icmp_code) {
+      case 0: /* Mobile-Ip */
+      case 16: /* Mobile-Ip */
+        type_str="Mobile IP Advertisement";
+        break;
+      default:
+        type_str="Router advertisement";
+        break;
+      } /* switch icmp_code */
+      break;
+    case ICMP_RTRSOLICIT:
+      type_str="Router solicitation";
+      break;
+    case ICMP_TIMXCEED:
+      type_str="Time-to-live exceeded";
+      if (icmp_code < N_TIMXCEED) {
+        code_str = ttl_str[icmp_code];
+      } else {
+        code_str = "Unknown - error?";
+      }
+      break;
+    case ICMP_PARAMPROB:
+      type_str="Parameter problem";
+      if (icmp_code < N_PARAMPROB) {
+        code_str = par_str[icmp_code];
+      } else {
+        code_str = "Unknown - error?";
+      }
+      break;
+    case ICMP_TSTAMP:
+      type_str="Timestamp request";
+      break;
+    case ICMP_TSTAMPREPLY:
+      type_str="Timestamp reply";
+      break;
+    case ICMP_IREQ:
+      type_str="Information request";
+      break;
+    case ICMP_IREQREPLY:
+      type_str="Information reply";
+      break;
+    case ICMP_MASKREQ:
+      type_str="Address mask request";
+      break;
+    case ICMP_MASKREPLY:
+      type_str="Address mask reply";
+      break;
+    default:
+      type_str="Unknown ICMP (obsolete or malformed?)";
+      break;
+  }
+
+  if (check_col(pinfo->cinfo, COL_INFO)) {
+    col_set_str(pinfo->cinfo, COL_INFO, type_str);
+    if (code_str[0] != '\0')
+      col_append_fstr(pinfo->cinfo, COL_INFO, " (%s)", code_str);
+  }
+
+  length = tvb_length(tvb);
+  reported_length = tvb_reported_length(tvb);
+
+  if (tree) {
+    proto_item *ti;
+
+    ti = proto_tree_add_item(tree, proto_icmp, tvb, 0, length, FALSE);
+    icmp_tree = proto_item_add_subtree(ti, ett_icmp);
+    proto_tree_add_uint_format(icmp_tree, hf_icmp_type, tvb, 0, 1,
+			       icmp_type,
+			       "Type: %u (%s)",
+			       icmp_type, type_str);
+    proto_tree_add_uint_format(icmp_tree, hf_icmp_code, tvb, 1, 1,
+			       icmp_code,
+			       "Code: %u (%s)",
+			       icmp_code, code_str);
+    if (!pinfo->fragmented && length >= reported_length) {
+      /* The packet isn't part of a fragmented datagram and isn't
+         truncated, so we can checksum it. */
+
+      computed_cksum = ip_checksum(tvb_get_ptr(tvb, 0, reported_length),
+	  			     reported_length);
+      if (computed_cksum == 0) {
+        proto_tree_add_uint_format(icmp_tree, hf_icmp_checksum, tvb, 2, 2,
+ 			  cksum,
+			  "Checksum: 0x%04x [correct]", cksum);
+      } else {
+        item = proto_tree_add_boolean(icmp_tree, hf_icmp_checksum_bad,
+			  tvb, 2, 2, TRUE);
+        PROTO_ITEM_SET_HIDDEN(item);
+        proto_tree_add_uint_format(icmp_tree, hf_icmp_checksum, tvb, 2, 2,
+		  cksum,
+		  "Checksum: 0x%04x [incorrect, should be 0x%04x]",
+		  cksum, in_cksum_shouldbe(cksum, computed_cksum));
+      }
+    } else {
+      proto_tree_add_uint(icmp_tree, hf_icmp_checksum, tvb, 2, 2, cksum);
+    }
+  }
+
+  /* Decode the second 4 bytes of the packet. */
+  switch (icmp_type) {
+      case ICMP_ECHOREPLY:
+      case ICMP_ECHO:
+      case ICMP_TSTAMP:
+      case ICMP_TSTAMPREPLY:
+      case ICMP_IREQ:
+      case ICMP_IREQREPLY:
+      case ICMP_MASKREQ:
+      case ICMP_MASKREPLY:
+        proto_tree_add_item(icmp_tree, hf_icmp_ident, tvb, 4, 2, FALSE);
+        proto_tree_add_item(icmp_tree, hf_icmp_seq_num, tvb, 6, 2, FALSE);
+	break;
+
+      case ICMP_UNREACH:
+        switch (icmp_code) {
+          case ICMP_FRAG_NEEDED:
+            proto_tree_add_item(icmp_tree, hf_icmp_mtu, tvb, 6, 2, FALSE);
+            break;
+	}
+        break;
+
+      case ICMP_RTRADVERT:
+        num_addrs = tvb_get_guint8(tvb, 4);
+	proto_tree_add_text(icmp_tree, tvb, 4, 1, "Number of addresses: %u",
+	  num_addrs);
+	addr_entry_size = tvb_get_guint8(tvb, 5);
+	proto_tree_add_text(icmp_tree, tvb, 5, 1, "Address entry size: %u",
+	  addr_entry_size);
+	proto_tree_add_text(icmp_tree, tvb, 6, 2, "Lifetime: %s",
+	  time_secs_to_str(tvb_get_ntohs(tvb, 6)));
+	break;
+
+      case ICMP_PARAMPROB:
+	proto_tree_add_text(icmp_tree, tvb, 4, 1, "Pointer: %u",
+	  tvb_get_guint8(tvb, 4));
+	break;
+
+      case ICMP_REDIRECT:
+        proto_tree_add_item(icmp_tree, hf_icmp_redir_gw, tvb, 4, 4, FALSE);
+	break;
+  }
+
+  /* Decode the additional information in the packet.  */
+  switch (icmp_type) {
+      case ICMP_UNREACH:
+      case ICMP_TIMXCEED:
+      case ICMP_PARAMPROB:
+      case ICMP_SOURCEQUENCH:
+      case ICMP_REDIRECT:
+	/* Save the current value of the "we're inside an error packet"
+	   flag, and set that flag; subdissectors may treat packets
+	   that are the payload of error packets differently from
+	   "real" packets. */
+	save_in_error_pkt = pinfo->in_error_pkt;
+	pinfo->in_error_pkt = TRUE;
+
+	/* Decode the IP header and first 64 bits of data from the
+	   original datagram. */
+	next_tvb = tvb_new_subset(tvb, 8, -1, -1);
+
+	/* There is a collision between RFC 1812 and draft-ietf-mpls-icmp-02.
+	We don't know how to decode the 128th and following bytes of the ICMP payload.
+	According to draft-ietf-mpls-icmp-02, these bytes should be decoded as MPLS extensions
+	whereas RFC 1812 tells us to decode them as a portion of the original packet.
+	Let the user decide.
+
+	Here the user decided to favor MPLS extensions.
+	Force the IP dissector to decode only the first 128 bytes. */
+	if ((tvb_reported_length(tvb) > 8 + 128) &&
+			favor_icmp_mpls_ext && (tvb_get_ntohs(tvb, 8 + 2) > 128))
+		set_actual_length(next_tvb, 128);
+
+	call_dissector(ip_handle, next_tvb, pinfo, icmp_tree);
+
+	/* Restore the "we're inside an error packet" flag. */
+	pinfo->in_error_pkt = save_in_error_pkt;
+
+	/* Decode MPLS extensions if the payload has at least 128 bytes, and
+		- the original packet in the ICMP payload has less than 128 bytes, or
+		- the user favors the MPLS extensions analysis */
+	if ((tvb_reported_length(tvb) > 8 + 128)
+			&& (tvb_get_ntohs(tvb, 8 + 2) <= 128 || favor_icmp_mpls_ext))
+		dissect_mpls_extensions(tvb, 8 + 128, icmp_tree);
+
+	break;
+
+      case ICMP_ECHOREPLY:
+      case ICMP_ECHO:
+	call_dissector(data_handle, tvb_new_subset(tvb, 8, -1, -1), pinfo,
+	               icmp_tree);
+	break;
+
+      case ICMP_RTRADVERT:
+        if (addr_entry_size == 2) {
+	  for (i = 0; i < num_addrs; i++) {
+	    proto_tree_add_text(icmp_tree, tvb, 8 + (i*8), 4,
+	      "Router address: %s",
+	      ip_to_str(tvb_get_ptr(tvb, 8 + (i*8), 4)));
+	    proto_tree_add_text(icmp_tree, tvb, 12 + (i*8), 4,
+	      "Preference level: %d", tvb_get_ntohl(tvb, 12 + (i*8)));
+	  }
+	  if ((icmp_code == 0) || (icmp_code == 16)) {
+		/* Mobile-Ip */
+		dissect_mip_extensions(tvb, 8 + i*8, icmp_tree);
+	  }
+	} else
+	  call_dissector(data_handle, tvb_new_subset(tvb, 8, -1, -1), pinfo,
+	                 icmp_tree);
+	break;
+
+      case ICMP_TSTAMP:
+      case ICMP_TSTAMPREPLY:
+	proto_tree_add_text(icmp_tree, tvb, 8, 4, "Originate timestamp: %s after midnight UTC",
+	  time_msecs_to_str(tvb_get_ntohl(tvb, 8)));
+	proto_tree_add_text(icmp_tree, tvb, 12, 4, "Receive timestamp: %s after midnight UTC",
+	  time_msecs_to_str(tvb_get_ntohl(tvb, 12)));
+	proto_tree_add_text(icmp_tree, tvb, 16, 4, "Transmit timestamp: %s after midnight UTC",
+	  time_msecs_to_str(tvb_get_ntohl(tvb, 16)));
+	break;
+
+    case ICMP_MASKREQ:
+    case ICMP_MASKREPLY:
+	proto_tree_add_text(icmp_tree, tvb, 8, 4, "Address mask: %s (0x%08x)",
+	  ip_to_str(tvb_get_ptr(tvb, 8, 4)), tvb_get_ntohl(tvb, 8));
+	break;
+  }
+}
+
+void
+proto_register_icmp(void)
+{
+  static hf_register_info hf[] = {
+
+    { &hf_icmp_type,
+      { "Type",		"icmp.type",		FT_UINT8, BASE_DEC,	NULL, 0x0,
+      	NULL, HFILL }},
+
+    { &hf_icmp_code,
+      { "Code",		"icmp.code",		FT_UINT8, BASE_HEX,	NULL, 0x0,
+      	NULL, HFILL }},
+
+    { &hf_icmp_checksum,
+      { "Checksum",	"icmp.checksum",	FT_UINT16, BASE_HEX,	NULL, 0x0,
+      	NULL, HFILL }},
+
+    { &hf_icmp_checksum_bad,
+      { "Bad Checksum",	"icmp.checksum_bad",	FT_BOOLEAN, BASE_NONE,	NULL, 0x0,
+	NULL, HFILL }},
+
+    { &hf_icmp_ident,
+      {"Identifier", "icmp.ident",              FT_UINT16, BASE_HEX,    NULL, 0x0,
+       NULL, HFILL }},
+
+    { &hf_icmp_seq_num,
+      {"Sequence number", "icmp.seq",           FT_UINT16, BASE_DEC_HEX,    NULL, 0x0,
+       NULL, HFILL }},
+
+    { &hf_icmp_mtu,
+      {"MTU of next hop", "icmp.mtu",           FT_UINT16, BASE_DEC,    NULL, 0x0,
+       NULL, HFILL}},
+
+    { &hf_icmp_redir_gw,
+      {"Gateway address", "icmp.redir_gw",      FT_IPv4, BASE_NONE,     NULL, 0x0,
+       NULL, HFILL }},
+
+    { &hf_icmp_mip_type,
+      { "Extension Type", "icmp.mip.type",	FT_UINT8, BASE_DEC,
+	VALS(mip_extensions), 0x0,NULL, HFILL}},
+
+    { &hf_icmp_mip_length,
+      { "Length", "icmp.mip.length",		FT_UINT8, BASE_DEC, NULL, 0x0,
+	NULL, HFILL}},
+
+    { &hf_icmp_mip_prefix_length,
+      { "Prefix Length", "icmp.mip.prefixlength",  FT_UINT8, BASE_DEC, NULL, 0x0,
+	NULL, HFILL}},
+
+    { &hf_icmp_mip_seq,
+      { "Sequence Number", "icmp.mip.seq",	FT_UINT16, BASE_DEC, NULL, 0x0,
+	NULL, HFILL}},
+
+    { &hf_icmp_mip_life,
+      { "Registration Lifetime", "icmp.mip.life",  FT_UINT16, BASE_DEC, NULL, 0x0,
+	NULL, HFILL}},
+
+    { &hf_icmp_mip_flags,
+      { "Flags", "icmp.mip.flags",            FT_UINT16, BASE_HEX, NULL, 0x0,
+	NULL, HFILL}},
+
+    { &hf_icmp_mip_r,
+      { "Registration Required", "icmp.mip.r", FT_BOOLEAN, 16, NULL, 32768,
+	"Registration with this FA is required", HFILL }},
+
+    { &hf_icmp_mip_b,
+      { "Busy", "icmp.mip.b", FT_BOOLEAN, 16, NULL, 16384,
+	"This FA will not accept requests at this time", HFILL }},
+
+    { &hf_icmp_mip_h,
+      { "Home Agent", "icmp.mip.h", FT_BOOLEAN, 16, NULL, 8192,
+	"Home Agent Services Offered", HFILL }},
+
+    { &hf_icmp_mip_f,
+      { "Foreign Agent", "icmp.mip.f", FT_BOOLEAN, 16, NULL, 4096,
+	"Foreign Agent Services Offered", HFILL }},
+
+    { &hf_icmp_mip_m,
+      { "Minimal Encapsulation", "icmp.mip.m", FT_BOOLEAN, 16, NULL, 2048,
+	"Minimal encapsulation tunneled datagram support", HFILL }},
+
+    { &hf_icmp_mip_g,
+      { "GRE", "icmp.mip.g", FT_BOOLEAN, 16, NULL, 1024,
+	"GRE encapsulated tunneled datagram support", HFILL }},
+
+    { &hf_icmp_mip_v,
+      { "VJ Comp", "icmp.mip.v", FT_BOOLEAN, 16, NULL, 512,
+	"Van Jacobson Header Compression Support", HFILL }},
+
+    { &hf_icmp_mip_rt,
+      { "Reverse tunneling", "icmp.mip.rt", FT_BOOLEAN, 16, NULL, 256,
+       "Reverse tunneling support", HFILL }},
+
+    { &hf_icmp_mip_u,
+      { "UDP tunneling", "icmp.mip.u", FT_BOOLEAN, 16, NULL, 128,
+       "UDP tunneling support", HFILL }},
+
+    { &hf_icmp_mip_x,
+      { "Revocation support", "icmp.mip.x", FT_BOOLEAN, 16, NULL, 64,
+       "Registration revocation support", HFILL }},
+
+
+    { &hf_icmp_mip_reserved,
+      { "Reserved", "icmp.mip.reserved",     FT_UINT16, BASE_HEX, NULL, 0x003f,
+	NULL, HFILL}},
+
+    { &hf_icmp_mip_coa,
+      { "Care-Of-Address", "icmp.mip.coa",    FT_IPv4, BASE_NONE, NULL, 0x0,
+	NULL, HFILL}},
+
+    { &hf_icmp_mip_challenge,
+      { "Challenge", "icmp.mip.challenge",    FT_BYTES, BASE_NONE, NULL, 0x0,
+	NULL, HFILL}},
+
+    { &hf_icmp_mpls,
+      { "ICMP Extensions for MPLS",	"icmp.mpls",	FT_NONE, BASE_NONE,	NULL, 0x0,
+	NULL, HFILL }},
+
+	{ &hf_icmp_mpls_version,
+		{ "Version",		"icmp.mpls.version", FT_UINT8, BASE_DEC, NULL, 0x0,
+			NULL, HFILL }},
+
+    { &hf_icmp_mpls_reserved,
+      { "Reserved",	"icmp.mpls.res",	FT_UINT16, BASE_HEX,	NULL, 0x0,
+      	NULL, HFILL }},
+
+	{ &hf_icmp_mpls_checksum,
+      { "Checksum",	"icmp.mpls.checksum",	FT_UINT16, BASE_HEX,	NULL, 0x0,
+      	NULL, HFILL }},
+
+	{ &hf_icmp_mpls_checksum_bad,
+      { "Bad Checksum",	"icmp.mpls.checksum_bad",	FT_BOOLEAN, BASE_NONE,	NULL, 0x0,
+	NULL, HFILL }},
+
+	{ &hf_icmp_mpls_length,
+      { "Length",	"icmp.mpls.length",	FT_UINT16, BASE_HEX,	NULL, 0x0,
+      	NULL, HFILL }},
+
+	{ &hf_icmp_mpls_class,
+		{ "Class",	"icmp.mpls.class", FT_UINT8, BASE_DEC, NULL, 0x0,
+			NULL, HFILL }},
+
+	{ &hf_icmp_mpls_c_type,
+		{ "C-Type",	"icmp.mpls.ctype", FT_UINT8, BASE_DEC, NULL, 0x0,
+			NULL, HFILL }},
+
+	{ &hf_icmp_mpls_label,
+		{ "Label",	"icmp.mpls.label", FT_UINT24, BASE_DEC, NULL, 0x00fffff0,
+			NULL, HFILL }},
+
+	{ &hf_icmp_mpls_exp,
+		{ "Experimental",	"icmp.mpls.exp", FT_UINT24, BASE_DEC,
+			NULL, 0x0e,
+			NULL, HFILL }},
+
+	{ &hf_icmp_mpls_s,
+		{ "Stack bit",	"icmp.mpls.s", FT_BOOLEAN, 24, TFS(&tfs_set_notset), 0x01,
+			NULL, HFILL }},
+
+	{ &hf_icmp_mpls_ttl,
+		{ "Time to live",	"icmp.mpls.ttl", FT_UINT8, BASE_DEC, NULL, 0x0,
+			NULL, HFILL }}
+
+  };
+  static gint *ett[] = {
+    &ett_icmp,
+	&ett_icmp_mip,
+	&ett_icmp_mip_flags,
+	/* MPLS extensions */
+	&ett_icmp_mpls,
+	&ett_icmp_mpls_object,
+	&ett_icmp_mpls_stack_object
+  };
+
+  module_t *icmp_module;
+
+  proto_icmp = proto_register_protocol("Internet Control Message Protocol",
+				       "ICMP", "icmp");
+  proto_register_field_array(proto_icmp, hf, array_length(hf));
+  proto_register_subtree_array(ett, array_length(ett));
+
+  icmp_module = prefs_register_protocol(proto_icmp, NULL);
+
+  prefs_register_bool_preference(icmp_module, "favor_icmp_mpls",
+	    "Favor ICMP extensions for MPLS",
+	    "Whether the 128th and following bytes of the ICMP payload should be decoded as MPLS extensions or as a portion of the original packet",
+	    &favor_icmp_mpls_ext);
+
+  register_dissector("icmp", dissect_icmp, proto_icmp);
+}
+
+void
+proto_reg_handoff_icmp(void)
+{
+  dissector_handle_t icmp_handle;
+
+  /*
+   * Get handle for the IP dissector.
+   */
+  ip_handle = find_dissector("ip");
+  icmp_handle = find_dissector("icmp");
+  data_handle = find_dissector("data");
+
+  dissector_add("ip.proto", IP_PROTO_ICMP, icmp_handle);
+}