Wireshark · Ethereal-dev: [Ethereal-dev] [patch] add LLS support to OSPF dissector

[Michael Rozhavsky <mrozhavsky@xxxxxxxxxxxx>]

Hi,

This patch adds support for draft-nguyen-ospf-lls-05.txt,
draft-nguyen-ospf-oob-resync-05.txt and
draft-nguyen-ospf-restart-05.txt. These are an alternative way to do
OSPF graceful restart.

These drafts are implemented by cisco and several other vendors that
want to interoperate with cisco. My patch adds a dissectors for LLS TLVs.

I had to modify the existing ospf dissector as it assumed that all the
data after IP header is OSPF packet. This is not true anymore and
probably was not true before as well.

Also please find attached an example of OSPF packets with LLS data blocks.
-- 
   Michael Rozhavsky
   Senior Manager, Software Development
   Fortinet (Canada) Inc.
   4710 Kingsway, Suite 400        Tel: (604) 430-1297 ext. 309
   Burnaby, BC  V5H 4M2  Canada    Fax: (604) 430-1296

Index: packet-ospf.c
===================================================================
--- packet-ospf.c	(revision 16809)
+++ packet-ospf.c	(working copy)
@@ -4,6 +4,12 @@
  *
  * $Id$
  *
+ * Added support for OSPF restart signaling:
+ *       draft-nguyen-ospf-lls-05.txt
+ *       draft-nguyen-ospf-oob-resync-05.txt
+ *       draft-nguyen-ospf-restart-05.txt
+ *   - (c) 2005 Michael Rozhavsky <mrozhavsky@xxxxxxxxxxxx>
+ * 
  * At this time, this module is able to analyze OSPF
  * packets as specified in RFC2328. MOSPF (RFC1584) and other
  * OSPF Extensions which introduce new Packet types
@@ -85,7 +91,7 @@
 #define OSPF_V2_OPTIONS_E		0x02
 #define OSPF_V2_OPTIONS_MC		0x04
 #define OSPF_V2_OPTIONS_NP		0x08
-#define OSPF_V2_OPTIONS_EA		0x10
+#define OSPF_V2_OPTIONS_L		0x10
 #define OSPF_V2_OPTIONS_DC		0x20
 #define OSPF_V2_OPTIONS_O		0x40
 #define OSPF_V3_OPTIONS_V6              0x01
@@ -95,7 +101,10 @@
 #define OSPF_V3_OPTIONS_R		0x10
 #define OSPF_V3_OPTIONS_DC		0x20
 
+#define OSPF_LLS_EXT_OPTIONS_LR		0x00000001
+#define OSPF_LLS_EXT_OPTIONS_RS		0x00000002
 
+
 #define OSPF_DBD_FLAG_MS	1
 #define OSPF_DBD_FLAG_M		2
 #define OSPF_DBD_FLAG_I		4
@@ -177,6 +186,12 @@
 
 };
 
+static const value_string lls_tlv_type_vals[] = {
+	{1,                                   "Extended options TLV"         },
+	{2,                                   "Crypo Authentication TLV"     },
+	{0,                                   NULL                           },
+};
+
 static const value_string mpls_link_stlv_ltype_str[] = {
     {1, "Point-to-point"},
     {2, "Multi-access"},
@@ -203,7 +218,7 @@
 static int hf_ospf_options_v2_e = -1;
 static int hf_ospf_options_v2_mc = -1;
 static int hf_ospf_options_v2_np = -1;
-static int hf_ospf_options_v2_ea = -1;
+static int hf_ospf_options_v2_l = -1;
 static int hf_ospf_options_v2_dc = -1;
 static int hf_ospf_options_v2_o = -1;
 static int hf_ospf_options_v2_dn = -1;
@@ -218,6 +233,9 @@
 static int hf_ospf_dbd_i = -1;
 static int hf_ospf_dbd_m = -1;
 static int hf_ospf_dbd_ms = -1;
+static int hf_ospf_lls_ext_options = -1;
+static int hf_ospf_lls_ext_options_lr = -1;
+static int hf_ospf_lls_ext_options_rs = -1;
 
 static gint ett_ospf = -1;
 static gint ett_ospf_hdr = -1;
@@ -230,6 +248,9 @@
 static gint ett_ospf_options_v2 = -1;
 static gint ett_ospf_options_v3 = -1;
 static gint ett_ospf_dbd = -1;
+static gint ett_ospf_lls_data_block = -1;
+static gint ett_ospf_lls_tlv = -1;
+static gint ett_ospf_lls_ext_options = -1;
 
 /* Trees for opaque LSAs */
 static gint ett_ospf_lsa_mpls = -1;
@@ -246,9 +267,9 @@
 	"Demand Circuits are supported",
 	"Demand circuits are NOT supported"
 };
-static const true_false_string tfs_options_v2_ea = {
-	"External Attributes are supported",
-	"External attributes are NOT supported"
+static const true_false_string tfs_options_v2_l = {
+	"The packet contains LLS data block",
+	"The packet does NOT contain LLS data block"
 };
 static const true_false_string tfs_options_v2_np = {
 	"NSSA is supported",
@@ -307,6 +328,14 @@
 	"MS is SET",
 	"MS is NOT set"
 };
+static const true_false_string tfs_lls_ext_options_lr = {
+	"LSDB Resynchrinization (LR-bit) is SET",
+	"LSDB Resynchrinization (LR-bit) is NOT set"
+};
+static const true_false_string tfs_lls_ext_options_rs = {
+	"Restart Signal (RS-bit) is SET",
+	"Restart Signal (RS-bit) is NOT set"
+};
 
 /*-----------------------------------------------------------------------
  * OSPF Filtering
@@ -475,9 +504,9 @@
     {&hf_ospf_options_v2_np,
      { "NP", "ospf.options.v2.np", FT_BOOLEAN, 8, 
        TFS(&tfs_options_v2_np), OSPF_V2_OPTIONS_NP, "", HFILL }},
-    {&hf_ospf_options_v2_ea,
-     { "EA", "ospf.options.v2.ea", FT_BOOLEAN, 8, 
-       TFS(&tfs_options_v2_ea), OSPF_V2_OPTIONS_EA, "", HFILL }},
+    {&hf_ospf_options_v2_l,
+     { "L", "ospf.options.v2.l", FT_BOOLEAN, 8, 
+       TFS(&tfs_options_v2_l), OSPF_V2_OPTIONS_L, "", HFILL }},
     {&hf_ospf_options_v2_dc,
      { "DC", "ospf.options.v2.dc", FT_BOOLEAN, 8, 
        TFS(&tfs_options_v2_dc), OSPF_V2_OPTIONS_DC, "", HFILL }},
@@ -520,8 +549,15 @@
     {&hf_ospf_dbd_ms,
      { "MS", "ospf.dbd.ms", FT_BOOLEAN, 8, 
        TFS(&tfs_dbd_ms), OSPF_DBD_FLAG_MS, "", HFILL }},
-
-
+    {&hf_ospf_lls_ext_options,
+     { "Options", "ospf.lls.ext.options", FT_UINT32, BASE_HEX,
+       NULL, 0x0, "", HFILL }},
+    {&hf_ospf_lls_ext_options_lr,
+     { "LR", "ospf.lls.ext.options.lr", FT_BOOLEAN, 32, 
+       TFS(&tfs_lls_ext_options_lr), OSPF_LLS_EXT_OPTIONS_LR, "", HFILL }},
+    {&hf_ospf_lls_ext_options_rs,
+     { "RS", "ospf.lls.ext.options.rs", FT_BOOLEAN, 32, 
+       TFS(&tfs_lls_ext_options_rs), OSPF_LLS_EXT_OPTIONS_RS, "", HFILL }},
 };
 
 static guint8 ospf_msg_type_to_filter (guint8 msg_type)
@@ -546,11 +582,12 @@
 
 static dissector_handle_t data_handle;
 
-static void dissect_ospf_hello(tvbuff_t*, int, proto_tree*, guint8);
-static void dissect_ospf_db_desc(tvbuff_t*, int, proto_tree*, guint8);
-static void dissect_ospf_ls_req(tvbuff_t*, int, proto_tree*, guint8);
-static void dissect_ospf_ls_upd(tvbuff_t*, int, proto_tree*, guint8);
-static void dissect_ospf_ls_ack(tvbuff_t*, int, proto_tree*, guint8);
+static void dissect_ospf_hello(tvbuff_t*, int, proto_tree*, guint8, guint16);
+static void dissect_ospf_db_desc(tvbuff_t*, int, proto_tree*, guint8, guint16);
+static void dissect_ospf_ls_req(tvbuff_t*, int, proto_tree*, guint8, guint16);
+static void dissect_ospf_ls_upd(tvbuff_t*, int, proto_tree*, guint8, guint16);
+static void dissect_ospf_ls_ack(tvbuff_t*, int, proto_tree*, guint8, guint16);
+static void dissect_ospf_lls_data_block(tvbuff_t*, int, proto_tree*, guint8);
 
 /* dissect_ospf_v[23]lsa returns the offset of the next LSA
  * if disassemble_body is set to FALSE (e.g. in LSA ACK
@@ -566,6 +603,24 @@
 
 static void dissect_ospf_v3_address_prefix(tvbuff_t *, int, int, proto_tree *);
 
+static int 
+ospf_has_lls_block(tvbuff_t *tvb, int offset, guint8 packet_type)
+{
+    guint8 flags;
+
+    /* LLS block can be found only in HELLO and DBDESC packets */
+    switch (packet_type) {
+    case OSPF_HELLO:
+	flags = tvb_get_guint8 (tvb, offset + 6);
+	return flags & OSPF_V2_OPTIONS_L;
+    case OSPF_DB_DESC:
+	flags = tvb_get_guint8 (tvb, offset + 2);
+	return flags & OSPF_V2_OPTIONS_L;
+    }
+
+    return 0;
+}
+
 static void
 dissect_ospf(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 {
@@ -582,7 +637,7 @@
     guint length, reported_length;
     guint16 auth_type;
     char auth_data[8+1];
-    int crypto_len;
+    int crypto_len = 0;
     unsigned int ospf_header_length;
     guint8 instance_ID;
     guint8 reserved;
@@ -616,7 +671,7 @@
     if (tree) {
 	ospflen = tvb_get_ntohs(tvb, 2);
 
-	ti = proto_tree_add_item(tree, proto_ospf, tvb, 0, ospflen, FALSE);
+	ti = proto_tree_add_item(tree, proto_ospf, tvb, 0, -1, FALSE);
 	ospf_tree = proto_item_add_subtree(ti, ett_ospf);
 
 	ti = proto_tree_add_text(ospf_tree, tvb, 0, ospf_header_length,
@@ -789,32 +844,31 @@
 	    break;
 	}
 
-	/* Adjust the length of the tvbuff to match the size of the OSPF
-	 * packet (since the dissect routines use it to work out where the
-	 * end of the OSPF packet is).
-	 */
-	tvb_set_reported_length(tvb, ospflen);
-
 	switch (packet_type){
 
 	case OSPF_HELLO:
-	    dissect_ospf_hello(tvb, ospf_header_length, ospf_tree, version);
+	    dissect_ospf_hello(tvb, ospf_header_length, ospf_tree, version, 
+			    ospflen - ospf_header_length);
 	    break;
 
 	case OSPF_DB_DESC:
-	    dissect_ospf_db_desc(tvb, ospf_header_length, ospf_tree, version);
+	    dissect_ospf_db_desc(tvb, ospf_header_length, ospf_tree, version, 
+			    ospflen - ospf_header_length);
 	    break;
 
 	case OSPF_LS_REQ:
-	    dissect_ospf_ls_req(tvb, ospf_header_length, ospf_tree, version);
+	    dissect_ospf_ls_req(tvb, ospf_header_length, ospf_tree, version, 
+			    ospflen - ospf_header_length);
 	    break;
 
 	case OSPF_LS_UPD:
-	    dissect_ospf_ls_upd(tvb, ospf_header_length, ospf_tree, version);
+	    dissect_ospf_ls_upd(tvb, ospf_header_length, ospf_tree, version, 
+			    ospflen - ospf_header_length);
 	    break;
 
 	case OSPF_LS_ACK:
-	    dissect_ospf_ls_ack(tvb, ospf_header_length, ospf_tree, version);
+	    dissect_ospf_ls_ack(tvb, ospf_header_length, ospf_tree, version, 
+			    ospflen - ospf_header_length);
 	    break;
 
 	default:
@@ -822,16 +876,118 @@
 	        tvb_new_subset(tvb, ospf_header_length, -1, -1), pinfo, tree);
 	    break;
 	}
+
+	/* take care of the LLS data block */
+	if (ospf_has_lls_block(tvb, ospf_header_length, packet_type))
+	    dissect_ospf_lls_data_block(tvb, ospflen + crypto_len, ospf_tree, 
+			    version);
     }
 }
 
+
 static void
-dissect_ospf_hello(tvbuff_t *tvb, int offset, proto_tree *tree, guint8 version)
+dissect_ospf_lls_extended_options (proto_tree *parent_tree, tvbuff_t *tvb, 
+		int offset)
 {
+	proto_item *item=NULL;
+	proto_tree *tree=NULL;
+	guint32 options;
+
+	options = tvb_get_ntohl(tvb, offset);
+	item=proto_tree_add_uint(parent_tree, hf_ospf_lls_ext_options, 
+			tvb, offset, 4, options);
+	tree=proto_item_add_subtree(item, ett_ospf_lls_ext_options);
+
+	proto_tree_add_boolean(tree, hf_ospf_lls_ext_options_lr, tvb, offset, 
+			4, options);
+	if (options & OSPF_LLS_EXT_OPTIONS_LR){
+		proto_item_append_text(item, "  LR");
+	}
+	options &=  ~OSPF_LLS_EXT_OPTIONS_LR;
+
+	proto_tree_add_boolean(tree, hf_ospf_lls_ext_options_rs, tvb, offset, 
+			4, options);
+	if (options & OSPF_LLS_EXT_OPTIONS_RS){
+		proto_item_append_text(item, "  RS");
+	}
+	options &=  ~OSPF_LLS_EXT_OPTIONS_RS;
+}
+
+static int
+dissect_ospf_lls_tlv(tvbuff_t *tvb, int offset, proto_tree *tree)
+{
+    proto_item *ti;
+    proto_tree *ospf_lls_tlv_tree;
+    guint16 type;
+    guint16 length;
+
+    type = tvb_get_ntohs(tvb, offset);
+    length = tvb_get_ntohs(tvb, offset + 2);
+
+    ti = proto_tree_add_text(tree, tvb, offset, length + 4, 
+		    val_to_str(type, lls_tlv_type_vals, "Unknown TLV"));
+    ospf_lls_tlv_tree = proto_item_add_subtree(ti, ett_ospf_lls_tlv);
+    
+    proto_tree_add_text(ospf_lls_tlv_tree, tvb, offset, 2,
+		    "Type: %d", type);
+    proto_tree_add_text(ospf_lls_tlv_tree, tvb, offset + 2, 2,
+		    "Length: %d", length);
+      
+    switch(type) {
+	case 1:
+	    dissect_ospf_lls_extended_options(ospf_lls_tlv_tree, tvb, 
+			    offset + 4);
+	    break;
+	case 2:
+	    proto_tree_add_text(ospf_lls_tlv_tree, tvb, offset + 4, 4, 
+			    "Sequence number 0x%08x", 
+			    tvb_get_ntohl(tvb, offset + 4));
+	    proto_tree_add_text(ospf_lls_tlv_tree, tvb, offset + 8, length - 4,
+			    "Auth Data: %s", 
+			    tvb_bytes_to_str(tvb, offset + 8, length - 4));
+	    break;
+    }
+
+    return offset + length + 4;
+}
+
+static void
+dissect_ospf_lls_data_block(tvbuff_t *tvb, int offset, proto_tree *tree, 
+		guint8 version)
+{
+    proto_tree *ospf_lls_data_block_tree;
+    proto_item *ti;
+    guint16 ospf_lls_len;
+    int orig_offset = offset;
+
+    ospf_lls_len = tvb_get_ntohs(tvb, offset + 2);
+    ti = proto_tree_add_text(tree, tvb, offset, -1, "OSPF LLS Data Block");
+    ospf_lls_data_block_tree = proto_item_add_subtree(ti, 
+		    ett_ospf_lls_data_block);
+
+    if (version != OSPF_VERSION_2)
+	    return;
+
+    /* TODO: verify checksum */
+    proto_tree_add_text(ospf_lls_data_block_tree, tvb, offset, 2, 
+		    "Checksum: 0x%04x", tvb_get_ntohs(tvb, offset));
+    proto_tree_add_text(ospf_lls_data_block_tree, tvb, offset + 2, 2,
+		    "LLS Data Length: %d bytes", ospf_lls_len * 4);
+    
+    offset += 4;
+    while (orig_offset + ospf_lls_len * 4 > offset)
+	offset = dissect_ospf_lls_tlv (tvb, offset, ospf_lls_data_block_tree);
+}
+
+static void
+dissect_ospf_hello(tvbuff_t *tvb, int offset, proto_tree *tree, guint8 version, 
+		guint16 length)
+{
     proto_tree *ospf_hello_tree;
     proto_item *ti;
+    int orig_offset = offset;
 
-    ti = proto_tree_add_text(tree, tvb, offset, -1, "OSPF Hello Packet");
+    ti = proto_tree_add_text(tree, tvb, offset, length, "OSPF Hello Packet");
     ospf_hello_tree = proto_item_add_subtree(ti, ett_ospf_hello);
 
     switch (version ) {
@@ -853,7 +1009,7 @@
 			ip_to_str(tvb_get_ptr(tvb, offset + 16, 4)));
 
             offset += 20;
-            while (tvb_reported_length_remaining(tvb, offset) != 0) {
+            while (orig_offset + length > offset) {
 	        proto_tree_add_text(ospf_hello_tree, tvb, offset, 4,
 			    "Active Neighbor: %s",
 			    ip_to_str(tvb_get_ptr(tvb, offset, 4)));
@@ -876,7 +1032,7 @@
             proto_tree_add_text(ospf_hello_tree, tvb, offset + 16, 4, "Backup Designated Router: %s",
 			ip_to_str(tvb_get_ptr(tvb, offset + 16, 4)));
             offset += 20;
-            while (tvb_reported_length_remaining(tvb, offset) != 0) {
+            while (orig_offset + length > offset) {
 	        proto_tree_add_text(ospf_hello_tree, tvb, offset, 4,
 			    "Active Neighbor: %s",
 			    ip_to_str(tvb_get_ptr(tvb, offset, 4)));
@@ -922,14 +1078,16 @@
 
 
 static void
-dissect_ospf_db_desc(tvbuff_t *tvb, int offset, proto_tree *tree, guint8 version)
+dissect_ospf_db_desc(tvbuff_t *tvb, int offset, proto_tree *tree, 
+		guint8 version, guint16 length)
 {
     proto_tree *ospf_db_desc_tree=NULL;
     proto_item *ti;
     guint8 reserved;
+    int orig_offset = offset;
 
     if (tree) {
-	ti = proto_tree_add_text(tree, tvb, offset, -1, "OSPF DB Description");
+	ti = proto_tree_add_text(tree, tvb, offset, length, "OSPF DB Description");
 	ospf_db_desc_tree = proto_item_add_subtree(ti, ett_ospf_desc);
 
         switch (version ) {
@@ -975,7 +1133,7 @@
 
     /* LS Headers will be processed here */
     /* skip to the end of DB-Desc header */
-    while (tvb_reported_length_remaining(tvb, offset) != 0) {
+    while (orig_offset + length > offset) {
       if ( version == OSPF_VERSION_2)
           offset = dissect_ospf_v2_lsa(tvb, offset, tree, FALSE);
       else
@@ -986,16 +1144,18 @@
 }
 
 static void
-dissect_ospf_ls_req(tvbuff_t *tvb, int offset, proto_tree *tree, guint8 version)
+dissect_ospf_ls_req(tvbuff_t *tvb, int offset, proto_tree *tree, guint8 version,
+		guint16 length)
 {
     proto_tree *ospf_lsr_tree;
     proto_item *ti;
     guint32 ls_type;
     guint16 reserved;
+    int orig_offset = offset;
 
     /* zero or more LS requests may be within a LS Request */
     /* we place every request for a LSA in a single subtree */
-    while (tvb_reported_length_remaining(tvb, offset) != 0) {
+    while (orig_offset + length > offset) {
 	ti = proto_tree_add_text(tree, tvb, offset, OSPF_LS_REQ_LENGTH,
 				 "Link State Request");
 	ospf_lsr_tree = proto_item_add_subtree(ti, ett_ospf_lsr);
@@ -1029,14 +1189,15 @@
 }
 
 static void
-dissect_ospf_ls_upd(tvbuff_t *tvb, int offset, proto_tree *tree, guint8 version)
+dissect_ospf_ls_upd(tvbuff_t *tvb, int offset, proto_tree *tree, guint8 version,
+		guint16 length)
 {
     proto_tree *ospf_lsa_upd_tree=NULL;
     proto_item *ti;
     guint32 lsa_nr;
     guint32 lsa_counter;
 
-    ti = proto_tree_add_text(tree, tvb, offset, -1, "LS Update Packet");
+    ti = proto_tree_add_text(tree, tvb, offset, length, "LS Update Packet");
     ospf_lsa_upd_tree = proto_item_add_subtree(ti, ett_ospf_lsa_upd);
 
     lsa_nr = tvb_get_ntohl(tvb, offset);
@@ -1057,10 +1218,12 @@
 }
 
 static void
-dissect_ospf_ls_ack(tvbuff_t *tvb, int offset, proto_tree *tree, guint8 version)
+dissect_ospf_ls_ack(tvbuff_t *tvb, int offset, proto_tree *tree, guint8 version,
+		guint16 length)
 {
+    int orig_offset = offset;
     /* the body of a LS Ack packet simply contains zero or more LSA Headers */
-    while (tvb_reported_length_remaining(tvb, offset) != 0) {
+    while (orig_offset + length > offset) {
         if ( version == OSPF_VERSION_2)
 	    offset = dissect_ospf_v2_lsa(tvb, offset, tree, FALSE);
         else
@@ -2341,11 +2504,11 @@
 	}
 	flags&=(~( OSPF_V2_OPTIONS_DC ));
 
-	proto_tree_add_boolean(tree, hf_ospf_options_v2_ea, tvb, offset, 1, flags);
-	if (flags&OSPF_V2_OPTIONS_EA){
-		proto_item_append_text(item, "  EA");
+	proto_tree_add_boolean(tree, hf_ospf_options_v2_l, tvb, offset, 1, flags);
+	if (flags&OSPF_V2_OPTIONS_L){
+		proto_item_append_text(item, "  L");
 	}
-	flags&=(~( OSPF_V2_OPTIONS_EA ));
+	flags&=(~( OSPF_V2_OPTIONS_L ));
 
 	proto_tree_add_boolean(tree, hf_ospf_options_v2_np, tvb, offset, 1, flags);
 	if (flags&OSPF_V2_OPTIONS_NP){
@@ -2543,7 +2706,10 @@
         &ett_ospf_lsa_oif_tna_stlv,
         &ett_ospf_options_v2,
         &ett_ospf_options_v3,
-        &ett_ospf_dbd
+        &ett_ospf_dbd,
+	&ett_ospf_lls_data_block,
+	&ett_ospf_lls_tlv,
+	&ett_ospf_lls_ext_options,
     };
 
     proto_ospf = proto_register_protocol("Open Shortest Path First",

Attachment: ospf-lls.pcap
Description: Binary data