/* conversation.c
 * Routines for building lists of packets that are part of a "conversation"
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <string.h>
#include <glib.h>
#include "packet.h"
#include "to_str.h"
#include "conversation.h"

/* define DEBUG_CONVERSATION for pretty debug printing */
/* #define DEBUG_CONVERSATION */
#include "conversation_debug.h"

#ifdef DEBUG_CONVERSATION
int _debug_conversation_indent = 0;
#endif

/*
 * Hash table for conversations with no wildcards.
 */
static GHashTable *conversation_hashtable_exact = NULL;

/*
 * Hash table for conversations with one wildcard address.
 */
static GHashTable *conversation_hashtable_no_addr2 = NULL;

/*
 * Hash table for conversations with one wildcard port.
 */
static GHashTable *conversation_hashtable_no_port2 = NULL;

/*
 * Hash table for conversations with one wildcard address and port.
 */
static GHashTable *conversation_hashtable_no_addr2_or_port2 = NULL;


#ifdef __NOT_USED__
typedef struct conversation_key {
	struct conversation_key *next;
	address	addr1;
	address	addr2;
	port_type ptype;
	guint32	port1;
	guint32	port2;
} conversation_key;
#endif
/*
 * Linked list of conversation keys, so we can, before freeing them all,
 * free the address data allocations associated with them.
 */
static conversation_key *conversation_keys;

static guint32 new_index;

/*
 * Protocol-specific data attached to a conversation_t structure - protocol
 * index and opaque pointer.
 */
typedef struct _conv_proto_data {
	int	proto;
	void	*proto_data;
} conv_proto_data;

/*
 * Creates a new conversation with known endpoints based on a conversation
 * created with the CONVERSATION_TEMPLATE option while keeping the
 * conversation created with the CONVERSATION_TEMPLATE option so it can still
 * match future connections.
 *
 * Passing a pointer to a conversation whose options mask does not include
 * CONVERSATION_TEMPLATE or where the conversation's protocol type (ptype)
 * indicates a non-connnection oriented protocol will return the conversation
 * without changes.
 *
 * addr2 and port2 are used in the function if their respective conversation
 * options bits are set (NO_ADDR2 and NO_PORT2).
 */
static conversation_t *
conversation_create_from_template(conversation_t *conversation, const address *addr2, const guint32 port2)
{
	/*
	 * Add a new conversation and keep the conversation template only if the
	 * CONVERSATION_TEMPLATE bit is set for a connection oriented protocol.
	 */
	if(conversation->options & CONVERSATION_TEMPLATE &&
		conversation->key_ptr->ptype != PT_UDP)
	{
		/*
		 * Set up a new options mask where the conversation template bit and the
		 * bits for absence of a second address and port pair have been removed.
		 */
		conversation_t *new_conversation_from_template;
		guint options = conversation->options & ~(CONVERSATION_TEMPLATE | NO_ADDR2 | NO_PORT2);

		/*
		 * Are both the NO_ADDR2 and NO_PORT2 wildcards set in the options mask?
		 */
		if(conversation->options & NO_ADDR2 &&
			conversation->options & NO_PORT2)
		{
			/*
			 * The conversation template was created without knowledge of both
			 * the second address as well as the second port. Create a new
			 * conversation with new 2nd address and 2nd port.
			 */
			new_conversation_from_template =
				conversation_new(conversation->setup_frame,
						 &conversation->key_ptr->addr1, addr2,
						 conversation->key_ptr->ptype, conversation->key_ptr->port1,
						 port2, options);
		}
		else if(conversation->options & NO_PORT2)
		{
			/*
			 * The conversation template was created without knowledge of port 2
			 * only. Create a new conversation with new 2nd port.
			 */
			new_conversation_from_template =
				conversation_new(conversation->setup_frame,
						 &conversation->key_ptr->addr1, &conversation->key_ptr->addr2,
						 conversation->key_ptr->ptype, conversation->key_ptr->port1,
						 port2, options);
		}
		else if(conversation->options & NO_ADDR2)
		{
			/*
			 * The conversation template was created without knowledge of address
			 * 2. Create a new conversation with new 2nd address.
			 */
			new_conversation_from_template =
				conversation_new(conversation->setup_frame,
						 &conversation->key_ptr->addr1, addr2,
						 conversation->key_ptr->ptype, conversation->key_ptr->port1,
						 conversation->key_ptr->port2, options);
		}
		else
		{
			/*
			 * The CONVERSATION_TEMPLATE bit was set, but no other bit that the
			 * CONVERSATION_TEMPLATE bit controls is active. Just return the old
			 * conversation.
			 */
			return conversation;
		}

		/*
		 * Set the protocol dissector used for the template conversation as
		 * the handler of the new conversation as well.
		 */
		new_conversation_from_template->dissector_tree = conversation->dissector_tree;

		return new_conversation_from_template;
	}
	else
	{
		return conversation;
	}
}

/*
 * Compute the hash value for two given address/port pairs if the match
 * is to be exact.
 */
/* http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx#existing
 * One-at-a-Time hash
 */
static guint
conversation_hash_exact(gconstpointer v)
{
	const conversation_key *key = (const conversation_key *)v;
	guint hash_val;
	address tmp_addr;

	hash_val = 0;
	tmp_addr.len  = 4;

	hash_val = add_address_to_hash(hash_val, &key->addr1);

	tmp_addr.data = &key->port1;
	hash_val = add_address_to_hash(hash_val, &tmp_addr);

	hash_val = add_address_to_hash(hash_val, &key->addr2);

	tmp_addr.data = &key->port2;
	hash_val = add_address_to_hash(hash_val, &tmp_addr);

	hash_val += ( hash_val << 3 );
	hash_val ^= ( hash_val >> 11 );
	hash_val += ( hash_val << 15 );

	return hash_val;
}

/*
 * Compare two conversation keys for an exact match.
 */
static gint
conversation_match_exact(gconstpointer v, gconstpointer w)
{
	const conversation_key *v1 = (const conversation_key *)v;
	const conversation_key *v2 = (const conversation_key *)w;

	if (v1->ptype != v2->ptype)
		return 0;	/* different types of port */

	/*
	 * Are the first and second port 1 values the same, the first and
	 * second port 2 values the same, the first and second address
	 * 1 values the same, and the first and second address 2 values
	 * the same?
	 */
	if (v1->port1 == v2->port1 &&
	    v1->port2 == v2->port2 &&
	    addresses_equal(&v1->addr1, &v2->addr1) &&
	    addresses_equal(&v1->addr2, &v2->addr2)) {
		/*
		 * Yes.  It's the same conversation, and the two
		 * address/port pairs are going in the same direction.
		 */
		return 1;
	}

	/*
	 * Is the first port 2 the same as the second port 1, the first
	 * port 1 the same as the second port 2, the first address 2
	 * the same as the second address 1, and the first address 1
	 * the same as the second address 2?
	 */
	if (v1->port2 == v2->port1 &&
	    v1->port1 == v2->port2 &&
	    addresses_equal(&v1->addr2, &v2->addr1) &&
	    addresses_equal(&v1->addr1, &v2->addr2)) {
		/*
		 * Yes.  It's the same conversation, and the two
		 * address/port pairs are going in opposite directions.
		 */
		return 1;
	}

	/*
	 * The addresses or the ports don't match.
	 */
	return 0;
}

/*
 * Compute the hash value for two given address/port pairs if the match
 * has a wildcard address 2.
 */
static guint
conversation_hash_no_addr2(gconstpointer v)
{
	const conversation_key *key = (const conversation_key *)v;
	guint hash_val;
	address tmp_addr;

	hash_val = 0;
	tmp_addr.len  = 4;

	hash_val = add_address_to_hash(hash_val, &key->addr1);

	tmp_addr.data = &key->port1;
	hash_val = add_address_to_hash(hash_val, &tmp_addr);

	tmp_addr.data = &key->port2;
	hash_val = add_address_to_hash(hash_val, &tmp_addr);

	hash_val += ( hash_val << 3 );
	hash_val ^= ( hash_val >> 11 );
	hash_val += ( hash_val << 15 );

	return hash_val;
}

/*
 * Compare two conversation keys, except for the address 2 value.
 * We don't check both directions of the conversation - the routine
 * doing the hash lookup has to do two searches, as the hash key
 * will be different for the two directions.
 */
static gint
conversation_match_no_addr2(gconstpointer v, gconstpointer w)
{
	const conversation_key *v1 = (const conversation_key *)v;
	const conversation_key *v2 = (const conversation_key *)w;

	if (v1->ptype != v2->ptype)
		return 0;	/* different types of port */

	/*
	 * Are the first and second port 1 values the same, the first and
	 * second port 2 valuess the same, and the first and second
	 * address 1 values the same?
	 */
	if (v1->port1 == v2->port1 &&
	    v1->port2 == v2->port2 &&
	    addresses_equal(&v1->addr1, &v2->addr1)) {
		/*
		 * Yes.  It's the same conversation, and the two
		 * address/port pairs are going in the same direction.
		 */
		return 1;
	}

	/*
	 * The addresses or the ports don't match.
	 */
	return 0;
}

/*
 * Compute the hash value for two given address/port pairs if the match
 * has a wildcard port 2.
 */
static guint
conversation_hash_no_port2(gconstpointer v)
{
	const conversation_key *key = (const conversation_key *)v;
	guint hash_val;
	address tmp_addr;

	hash_val = 0;
	tmp_addr.len  = 4;

	hash_val = add_address_to_hash(hash_val, &key->addr1);

	tmp_addr.data = &key->port1;
	hash_val = add_address_to_hash(hash_val, &tmp_addr);

	hash_val = add_address_to_hash(hash_val, &key->addr2);

	hash_val += ( hash_val << 3 );
	hash_val ^= ( hash_val >> 11 );
	hash_val += ( hash_val << 15 );

	return hash_val;
}

/*
 * Compare two conversation keys, except for the port 2 value.
 * We don't check both directions of the conversation - the routine
 * doing the hash lookup has to do two searches, as the hash key
 * will be different for the two directions.
 */
static gint
conversation_match_no_port2(gconstpointer v, gconstpointer w)
{
	const conversation_key *v1 = (const conversation_key *)v;
	const conversation_key *v2 = (const conversation_key *)w;

	if (v1->ptype != v2->ptype)
		return 0;	/* different types of port */

	/*
	 * Are the first and second port 1 values the same, the first and
	 * second address 1 values the same, and the first and second
	 * address 2 values the same?
	 */
	if (v1->port1 == v2->port1 &&
	    addresses_equal(&v1->addr1, &v2->addr1) &&
	    addresses_equal(&v1->addr2, &v2->addr2)) {
		/*
		 * Yes.  It's the same conversation, and the two
		 * address/port pairs are going in the same direction.
		 */
		return 1;
	}

	/*
	 * The addresses or the ports don't match.
	 */
	return 0;
}

/*
 * Compute the hash value for two given address/port pairs if the match
 * has a wildcard address 2 and port 2.
 */
static guint
conversation_hash_no_addr2_or_port2(gconstpointer v)
{
	const conversation_key *key = (const conversation_key *)v;
	guint hash_val;
	address tmp_addr;

	hash_val = 0;
	tmp_addr.len  = 4;

	hash_val = add_address_to_hash(hash_val, &key->addr1);

	tmp_addr.data = &key->port1;
	hash_val = add_address_to_hash(hash_val, &tmp_addr);

	hash_val += ( hash_val << 3 );
	hash_val ^= ( hash_val >> 11 );
	hash_val += ( hash_val << 15 );

	return hash_val;
}

/*
 * Compare the address 1 and port 1 in the two conversation keys.
 * We don't check both directions of the conversation - the routine
 * doing the hash lookup has to do two searches, as the hash key
 * will be different for the two directions.
 */
static gint
conversation_match_no_addr2_or_port2(gconstpointer v, gconstpointer w)
{
	const conversation_key *v1 = (const conversation_key *)v;
	const conversation_key *v2 = (const conversation_key *)w;

	if (v1->ptype != v2->ptype)
		return 0;	/* different types of port */

	/*
	 * Are the first and second port 1 values the same and the first
	 * and second address 1 values the same?
	 */
	if (v1->port1 == v2->port1 &&
	    addresses_equal(&v1->addr1, &v2->addr1)) {
		/*
		 * Yes.  It's the same conversation, and the two
		 * address/port pairs are going in the same direction.
		 */
		return 1;
	}

	/*
	 * The addresses or the ports don't match.
	 */
	return 0;
}

/*
 * Free the proto_data.  The conversation itself is wmem-allocated with
 * file scope.
 */
static void
free_data_list(gpointer value)
{
	conversation_t *conv = (conversation_t *)value;

	/* TODO: file scoped wmem_list? There's no singly-linked wmem_ list */
	g_slist_free(conv->data_list);

	/* Not really necessary, but... */
	conv->data_list = NULL;

}

/*
 * Destroy all existing conversations
 */
void
conversation_cleanup(void)
{
	/*  Clean up the hash tables, but only after freeing any proto_data
	 *  that may be hanging off the conversations.
	 *  The conversation keys are wmem-allocated with file scope so we
	 *  don't have to clean them up.
	 */
	conversation_keys = NULL;
	if (conversation_hashtable_exact != NULL) {
		g_hash_table_destroy(conversation_hashtable_exact);
	}
	if (conversation_hashtable_no_addr2 != NULL) {
		g_hash_table_destroy(conversation_hashtable_no_addr2);
	}
	if (conversation_hashtable_no_port2 != NULL) {
		g_hash_table_destroy(conversation_hashtable_no_port2);
	}
	if (conversation_hashtable_no_addr2_or_port2 != NULL) {
		g_hash_table_destroy(conversation_hashtable_no_addr2_or_port2);
	}

	conversation_hashtable_exact = NULL;
	conversation_hashtable_no_addr2 = NULL;
	conversation_hashtable_no_port2 = NULL;
	conversation_hashtable_no_addr2_or_port2 = NULL;
}

/*
 * Initialize some variables every time a file is loaded or re-loaded.
 * Create a new hash table for the conversations in the new file.
 */
void
conversation_init(void)
{
	/*
	 * Free up any space allocated for conversation protocol data
	 * areas.
	 *
	 * We can free the space, as the structures it contains are
	 * pointed to by conversation data structures that were freed
	 * above.
	 */
	conversation_hashtable_exact =
	    g_hash_table_new_full(conversation_hash_exact,
	      conversation_match_exact, NULL, free_data_list);
	conversation_hashtable_no_addr2 =
	    g_hash_table_new_full(conversation_hash_no_addr2,
	      conversation_match_no_addr2, NULL, free_data_list);
	conversation_hashtable_no_port2 =
	    g_hash_table_new_full(conversation_hash_no_port2,
	      conversation_match_no_port2, NULL, free_data_list);
	conversation_hashtable_no_addr2_or_port2 =
	    g_hash_table_new_full(conversation_hash_no_addr2_or_port2,
	      conversation_match_no_addr2_or_port2, NULL, free_data_list);

	/*
	 * Start the conversation indices over at 0.
	 */
	new_index = 0;
}

/*
 * Does the right thing when inserting into one of the conversation hash tables,
 * taking into account ordering and hash chains and all that good stuff.
 *
 * Mostly adapted from the old conversation_new().
 */
static void
conversation_insert_into_hashtable(GHashTable *hashtable, conversation_t *conv)
{
	conversation_t *chain_head, *chain_tail, *cur, *prev;

	chain_head = (conversation_t *)g_hash_table_lookup(hashtable, conv->key_ptr);

	if (NULL==chain_head) {
		/* New entry */
		conv->next = NULL;
		conv->last = conv;
		g_hash_table_insert(hashtable, conv->key_ptr, conv);
		DPRINT(("created a new conversation chain"));
	}
	else {
		/* There's an existing chain for this key */
		DPRINT(("there's an existing conversation chain"));

		chain_tail = chain_head->last;

		if(conv->setup_frame >= chain_tail->setup_frame) {
			/* This convo belongs at the end of the chain */
			conv->next = NULL;
			conv->last = NULL;
			chain_tail->next = conv;
			chain_head->last = conv;
		}
		else {
			/* Loop through the chain to find the right spot */
			cur = chain_head;
			prev = NULL;

			for (; (conv->setup_frame > cur->setup_frame) && cur->next; prev=cur, cur=cur->next)
				;

			if (NULL==prev) {
				/* Changing the head of the chain */
				conv->next = chain_head;
				conv->last = chain_tail;
				chain_head->last = NULL;
				g_hash_table_insert(hashtable, conv->key_ptr, conv);
			}
			else {
				/* Inserting into the middle of the chain */
				conv->next = cur;
				conv->last = NULL;
				prev->next = conv;
			}
		}
	}
}

/*
 * Does the right thing when removing from one of the conversation hash tables,
 * taking into account ordering and hash chains and all that good stuff.
 */
static void
conversation_remove_from_hashtable(GHashTable *hashtable, conversation_t *conv)
{
	conversation_t *chain_head, *cur, *prev;

	chain_head = (conversation_t *)g_hash_table_lookup(hashtable, conv->key_ptr);

	if (conv == chain_head) {
		/* We are currently the front of the chain */
		if (NULL == conv->next) {
			/* We are the only conversation in the chain, no need to
			 * update next pointer, but do not call
			 * g_hash_table_remove() either because the conv data
			 * will be re-inserted. The memory is released when
			 * conversion_cleanup() is called. */
			g_hash_table_steal(hashtable, conv->key_ptr);
		}
		else {
			/* Update the head of the chain */
			chain_head = conv->next;
			chain_head->last = conv->last;

			if (conv->latest_found == conv)
				chain_head->latest_found = NULL;
			else
				chain_head->latest_found = conv->latest_found;

			g_hash_table_insert(hashtable, chain_head->key_ptr, chain_head);
		}
	}
	else {
		/* We are not the front of the chain. Loop through to find us.
		 * Start loop at chain_head->next rather than chain_head because
		 * we already know we're not at the head. */
		cur = chain_head->next;
		prev = chain_head;

		for (; (cur != conv) && cur->next; prev=cur, cur=cur->next)
			;

		if (cur != conv) {
			/* XXX: Conversation not found. Wrong hashtable? */
			return;
		}

		prev->next = conv->next;

		if (NULL == conv->next) {
			/* We're at the very end of the list. */
			chain_head->last = prev;
		}

		if (chain_head->latest_found == conv)
			chain_head->latest_found = prev;
	}
}

/*
 * Given two address/port pairs for a packet, create a new conversation
 * to contain packets between those address/port pairs.
 *
 * The options field is used to specify whether the address 2 value
 * and/or port 2 value are not given and any value is acceptable
 * when searching for this conversation.
 */
conversation_t *
conversation_new(const guint32 setup_frame, const address *addr1, const address *addr2, const port_type ptype,
    const guint32 port1, const guint32 port2, const guint options)
{
/*
	DISSECTOR_ASSERT(!(options | CONVERSATION_TEMPLATE) || ((options | (NO_ADDR2 | NO_PORT2 | NO_PORT2_FORCE))) &&
				"A conversation template may not be constructed without wildcard options");
*/
	GHashTable* hashtable;
	conversation_t *conversation=NULL;
	conversation_key *new_key;

	DPRINT(("creating conversation for frame #%d: %s:%d -> %s:%d (ptype=%d)",
		    setup_frame, address_to_str(wmem_packet_scope(), addr1), port1,
		    address_to_str(wmem_packet_scope(), addr2), port2, ptype));

	if (options & NO_ADDR2) {
		if (options & (NO_PORT2|NO_PORT2_FORCE)) {
			hashtable = conversation_hashtable_no_addr2_or_port2;
		} else {
			hashtable = conversation_hashtable_no_addr2;
		}
	} else {
		if (options & (NO_PORT2|NO_PORT2_FORCE)) {
			hashtable = conversation_hashtable_no_port2;
		} else {
			hashtable = conversation_hashtable_exact;
		}
	}

	new_key = wmem_new(wmem_file_scope(), struct conversation_key);
	new_key->next = conversation_keys;
	conversation_keys = new_key;
	copy_address_wmem(wmem_file_scope(), &new_key->addr1, addr1);
	copy_address_wmem(wmem_file_scope(), &new_key->addr2, addr2);
	new_key->ptype = ptype;
	new_key->port1 = port1;
	new_key->port2 = port2;

	conversation = wmem_new(wmem_file_scope(), conversation_t);
	memset(conversation, 0, sizeof(conversation_t));

	conversation->conv_index = new_index;
	conversation->setup_frame = conversation->last_frame = setup_frame;
	conversation->data_list = NULL;

	conversation->dissector_tree = wmem_tree_new(wmem_file_scope());

	/* set the options and key pointer */
	conversation->options = options;
	conversation->key_ptr = new_key;

	new_index++;

	DINDENT();
	conversation_insert_into_hashtable(hashtable, conversation);
	DENDENT();

	return conversation;
}

/*
 * Set the port 2 value in a key.  Remove the original from table,
 * update the options and port values, insert the updated key.
 */
void
conversation_set_port2(conversation_t *conv, const guint32 port)
{
   DISSECTOR_ASSERT_HINT(!(conv->options & CONVERSATION_TEMPLATE),
            "Use the conversation_create_from_template function when the CONVERSATION_TEMPLATE bit is set in the options mask");

	DPRINT(("called for port=%d", port));

	/*
	 * If the port 2 value is not wildcarded, don't set it.
	 */
	if ((!(conv->options & NO_PORT2)) || (conv->options & NO_PORT2_FORCE))
		return;

	DINDENT();
	if (conv->options & NO_ADDR2) {
		conversation_remove_from_hashtable(conversation_hashtable_no_addr2_or_port2, conv);
	} else {
		conversation_remove_from_hashtable(conversation_hashtable_no_port2, conv);
	}
	conv->options &= ~NO_PORT2;
	conv->key_ptr->port2  = port;
	if (conv->options & NO_ADDR2) {
		conversation_insert_into_hashtable(conversation_hashtable_no_addr2, conv);
	} else {
		conversation_insert_into_hashtable(conversation_hashtable_exact, conv);
	}
	DENDENT();
}

/*
 * Set the address 2 value in a key.  Remove the original from
 * table, update the options and port values, insert the updated key.
 */
void
conversation_set_addr2(conversation_t *conv, const address *addr)
{
	char* addr_str;
	DISSECTOR_ASSERT_HINT(!(conv->options & CONVERSATION_TEMPLATE),
			"Use the conversation_create_from_template function when the CONVERSATION_TEMPLATE bit is set in the options mask");

	addr_str = address_to_str(NULL, addr);
	DPRINT(("called for addr=%s", addr_str));
	wmem_free(NULL, addr_str);

	/*
	 * If the address 2 value is not wildcarded, don't set it.
	 */
	if (!(conv->options & NO_ADDR2))
		return;

	DINDENT();
	if (conv->options & NO_PORT2) {
		conversation_remove_from_hashtable(conversation_hashtable_no_addr2_or_port2, conv);
	} else {
		conversation_remove_from_hashtable(conversation_hashtable_no_port2, conv);
	}
	conv->options &= ~NO_ADDR2;
	copy_address_wmem(wmem_file_scope(), &conv->key_ptr->addr2, addr);
	if (conv->options & NO_PORT2) {
		conversation_insert_into_hashtable(conversation_hashtable_no_port2, conv);
	} else {
		conversation_insert_into_hashtable(conversation_hashtable_exact, conv);
	}
	DENDENT();
}

/*
 * Search a particular hash table for a conversation with the specified
 * {addr1, port1, addr2, port2} and set up before frame_num.
 */
static conversation_t *
conversation_lookup_hashtable(GHashTable *hashtable, const guint32 frame_num, const address *addr1, const address *addr2,
    const port_type ptype, const guint32 port1, const guint32 port2)
{
	conversation_t* convo=NULL;
	conversation_t* match=NULL;
	conversation_t* chain_head=NULL;
	conversation_key key;

	/*
	 * We don't make a copy of the address data, we just copy the
	 * pointer to it, as "key" disappears when we return.
	 */
	key.addr1 = *addr1;
	key.addr2 = *addr2;
	key.ptype = ptype;
	key.port1 = port1;
	key.port2 = port2;

	chain_head = (conversation_t *)g_hash_table_lookup(hashtable, &key);

	if (chain_head && (chain_head->setup_frame <= frame_num)) {
		match = chain_head;

		if((chain_head->last)&&(chain_head->last->setup_frame<=frame_num))
			return chain_head->last;

		if((chain_head->latest_found)&&(chain_head->latest_found->setup_frame<=frame_num))
			match = chain_head->latest_found;

		for (convo = match; convo && convo->setup_frame <= frame_num; convo = convo->next) {
			if (convo->setup_frame > match->setup_frame) {
				match = convo;
			}
		}
	}

	if (match)
		chain_head->latest_found = match;

	return match;
}


/*
 * Given two address/port pairs for a packet, search for a conversation
 * containing packets between those address/port pairs.  Returns NULL if
 * not found.
 *
 * We try to find the most exact match that we can, and then proceed to
 * try wildcard matches on the "addr_b" and/or "port_b" argument if a more
 * exact match failed.
 *
 * Either or both of the "addr_b" and "port_b" arguments may be specified as
 * a wildcard by setting the NO_ADDR_B or NO_PORT_B flags in the "options"
 * argument.  We do only wildcard matches on addresses and ports specified
 * as wildcards.
 *
 * I.e.:
 *
 *	if neither "addr_b" nor "port_b" were specified as wildcards, we
 *	do an exact match (addr_a/port_a and addr_b/port_b) and, if that
 *	succeeds, we return a pointer to the matched conversation;
 *
 *	otherwise, if "port_b" wasn't specified as a wildcard, we try to
 *	match any address 2 with the specified port 2 (addr_a/port_a and
 *	{any}/port_b) and, if that succeeds, we return a pointer to the
 *	matched conversation;
 *
 *	otherwise, if "addr_b" wasn't specified as a wildcard, we try to
 *	match any port 2 with the specified address 2 (addr_a/port_a and
 *	addr_b/{any}) and, if that succeeds, we return a pointer to the
 *	matched conversation;
 *
 *	otherwise, we try to match any address 2 and any port 2
 *	(addr_a/port_a and {any}/{any}) and, if that succeeds, we return
 *	a pointer to the matched conversation;
 *
 *	otherwise, we found no matching conversation, and return NULL.
 */
conversation_t *
find_conversation(const guint32 frame_num, const address *addr_a, const address *addr_b, const port_type ptype,
    const guint32 port_a, const guint32 port_b, const guint options)
{
	conversation_t *conversation;

	/*
	 * First try an exact match, if we have two addresses and ports.
	 */
	if (!(options & (NO_ADDR_B|NO_PORT_B))) {
		/*
		 * Neither search address B nor search port B are wildcarded,
		 * start out with an exact match.
		 */
		DPRINT(("trying exact match"));
		conversation =
			conversation_lookup_hashtable(conversation_hashtable_exact,
			frame_num, addr_a, addr_b, ptype,
			port_a, port_b);
		/* Didn't work, try the other direction */
		if (conversation == NULL) {
			DPRINT(("trying opposite direction"));
			conversation =
				conversation_lookup_hashtable(conversation_hashtable_exact,
				frame_num, addr_b, addr_a, ptype,
				port_b, port_a);
		}
		if ((conversation == NULL) && (addr_a->type == AT_FC)) {
			/* In Fibre channel, OXID & RXID are never swapped as
			 * TCP/UDP ports are in TCP/IP.
			 */
			conversation =
				conversation_lookup_hashtable(conversation_hashtable_exact,
				frame_num, addr_b, addr_a, ptype,
				port_a, port_b);
		}
		DPRINT(("exact match %sfound",conversation?"":"not "));
		if (conversation != NULL)
			return conversation;
	}

	/*
	 * Well, that didn't find anything.  Try matches that wildcard
	 * one of the addresses, if we have two ports.
	 */
	if (!(options & NO_PORT_B)) {
		/*
		 * Search port B isn't wildcarded.
		 *
		 * First try looking for a conversation with the specified
		 * address A and port A as the first address and port, and
		 * with any address and the specified port B as the second
		 * address and port.
		 * ("addr_b" doesn't take part in this lookup.)
		 */
		DPRINT(("trying wildcarded dest address"));
		conversation =
			conversation_lookup_hashtable(conversation_hashtable_no_addr2,
			frame_num, addr_a, addr_b, ptype, port_a, port_b);
		if ((conversation == NULL) && (addr_a->type == AT_FC)) {
			/* In Fibre channel, OXID & RXID are never swapped as
			 * TCP/UDP ports are in TCP/IP.
			 */
			conversation =
				conversation_lookup_hashtable(conversation_hashtable_no_addr2,
				frame_num, addr_b, addr_a, ptype,
				port_a, port_b);
		}
		if (conversation != NULL) {
			/*
			 * If search address B isn't wildcarded, and this is for a
			 * connection-oriented protocol, set the second address for this
			 * conversation to address B, as that's the address that matched the
			 * wildcarded second address for this conversation.
			 *
			 * (This assumes that, for all connection oriented protocols, the
			 * endpoints of a connection have only one address each, i.e. you
			 * don't get packets in a given direction coming from more than one
			 * address, unless the CONVERSATION_TEMPLATE option is set.)
			 */
			DPRINT(("wildcarded dest address match found"));
			if (!(conversation->options & NO_ADDR_B) && ptype != PT_UDP)
			{
				if(!(conversation->options & CONVERSATION_TEMPLATE))
				{
					conversation_set_addr2(conversation, addr_b);
				}
				else
				{
					conversation =
						conversation_create_from_template(conversation, addr_b, 0);
				}
			}
			return conversation;
		}

		/*
		 * Well, that didn't find anything.
		 * If search address B was specified, try looking for a
		 * conversation with the specified address B and port B as
		 * the first address and port, and with any address and the
		 * specified port A as the second address and port (this
		 * packet may be going in the opposite direction from the
		 * first packet in the conversation).
		 * ("addr_a" doesn't take part in this lookup.)
		 */
		if (!(options & NO_ADDR_B)) {
			DPRINT(("trying dest addr:port as source addr:port with wildcarded dest addr"));
			conversation =
				conversation_lookup_hashtable(conversation_hashtable_no_addr2,
				frame_num, addr_b, addr_a, ptype, port_b, port_a);
			if (conversation != NULL) {
				/*
				 * If this is for a connection-oriented
				 * protocol, set the second address for
				 * this conversation to address A, as
				 * that's the address that matched the
				 * wildcarded second address for this
				 * conversation.
				 */
				DPRINT(("match found"));
				if (ptype != PT_UDP) {
					if(!(conversation->options & CONVERSATION_TEMPLATE))
					{
						conversation_set_addr2(conversation, addr_a);
					}
					else
					{
						conversation =
							conversation_create_from_template(conversation, addr_a, 0);
					}
				}
				return conversation;
			}
		}
	}

	/*
	 * Well, that didn't find anything.  Try matches that wildcard
	 * one of the ports, if we have two addresses.
	*/
	if (!(options & NO_ADDR_B)) {
		/*
		 * Search address B isn't wildcarded.
		 *
		 * First try looking for a conversation with the specified
		 * address A and port A as the first address and port, and
		 * with the specified address B and any port as the second
		 * address and port.
		 * ("port_b" doesn't take part in this lookup.)
		 */
		DPRINT(("trying wildcarded dest port"));
		conversation =
			conversation_lookup_hashtable(conversation_hashtable_no_port2,
			frame_num, addr_a, addr_b, ptype, port_a, port_b);
		if ((conversation == NULL) && (addr_a->type == AT_FC)) {
			/* In Fibre channel, OXID & RXID are never swapped as
			 * TCP/UDP ports are in TCP/IP
			 */
			conversation =
				conversation_lookup_hashtable(conversation_hashtable_no_port2,
				frame_num, addr_b, addr_a, ptype, port_a, port_b);
		}
		if (conversation != NULL) {
			/*
			 * If search port B isn't wildcarded, and this is for a connection-
			 * oriented protocol, set the second port for this conversation to
			 * port B, as that's the port that matched the wildcarded second port
			 * for this conversation.
			 *
			 * (This assumes that, for all connection oriented protocols, the
			 * endpoints of a connection have only one port each, i.e. you don't
			 * get packets in a given direction coming from more than one port,
			 * unless the CONVERSATION_TEMPLATE option is set.)
			 */
			DPRINT(("match found"));
			if (!(conversation->options & NO_PORT_B) && ptype != PT_UDP)
			{
				if(!(conversation->options & CONVERSATION_TEMPLATE))
				{
					conversation_set_port2(conversation, port_b);
				}
				else
				{
					conversation =
						conversation_create_from_template(conversation, 0, port_b);
				}
			}
			return conversation;
		}

		/*
		 * Well, that didn't find anything.
		 * If search port B was specified, try looking for a
		 * conversation with the specified address B and port B
		 * as the first address and port, and with the specified
		 * address A and any port as the second address and port
		 * (this packet may be going in the opposite direction
		 * from the first packet in the conversation).
		 * ("port_a" doesn't take part in this lookup.)
		 */
		if (!(options & NO_PORT_B)) {
			DPRINT(("trying dest addr:port as source addr:port and wildcarded dest port"));
			conversation =
				conversation_lookup_hashtable(conversation_hashtable_no_port2,
				frame_num, addr_b, addr_a, ptype, port_b, port_a);
			if (conversation != NULL) {
				/*
				 * If this is for a connection-oriented
				 * protocol, set the second port for
				 * this conversation to port A, as
				 * that's the address that matched the
				 * wildcarded second address for this
				 * conversation.
				 */
				DPRINT(("match found"));
				if (ptype != PT_UDP)
				{
					if(!(conversation->options & CONVERSATION_TEMPLATE))
					{
						conversation_set_port2(conversation, port_a);
					}
					else
					{
						conversation =
							conversation_create_from_template(conversation, 0, port_a);
					}
				}
				return conversation;
			}
		}
	}

	/*
	 * Well, that didn't find anything.  Try matches that wildcard
	 * one address/port pair.
	 *
	 * First try looking for a conversation with the specified address A
	 * and port A as the first address and port.
	 * (Neither "addr_b" nor "port_b" take part in this lookup.)
	 */
	DPRINT(("trying wildcarding dest addr:port"));
	conversation =
		conversation_lookup_hashtable(conversation_hashtable_no_addr2_or_port2,
		frame_num, addr_a, addr_b, ptype, port_a, port_b);
	if (conversation != NULL) {
		/*
		 * If this is for a connection-oriented protocol:
		 *
		 * if search address B isn't wildcarded, set the
		 * second address for this conversation to address
		 * B, as that's the address that matched the
		 * wildcarded second address for this conversation;
		 *
		 * if search port B isn't wildcarded, set the
		 * second port for this conversation to port B,
		 * as that's the port that matched the wildcarded
		 * second port for this conversation.
		 */
		DPRINT(("match found"));
		if (ptype != PT_UDP)
		{
			if(!(conversation->options & CONVERSATION_TEMPLATE))
			{
				if (!(conversation->options & NO_ADDR_B))
					conversation_set_addr2(conversation, addr_b);
				if (!(conversation->options & NO_PORT_B))
					conversation_set_port2(conversation, port_b);
			}
			else
			{
				conversation =
					conversation_create_from_template(conversation, addr_b, port_b);
			}
		}
		return conversation;
	}

	/*
	 * Well, that didn't find anything.
	 * If search address and port B were specified, try looking for a
	 * conversation with the specified address B and port B as the
	 * first address and port, and with any second address and port
	 * (this packet may be going in the opposite direction from the
	 * first packet in the conversation).
	 * (Neither "addr_a" nor "port_a" take part in this lookup.)
	 */
	DPRINT(("trying dest addr:port as source addr:port and wildcarding dest addr:port"));
	if (addr_a->type == AT_FC)
		conversation =
			conversation_lookup_hashtable(conversation_hashtable_no_addr2_or_port2,
			frame_num, addr_b, addr_a, ptype, port_a, port_b);
	else
		conversation =
			conversation_lookup_hashtable(conversation_hashtable_no_addr2_or_port2,
			frame_num, addr_b, addr_a, ptype, port_b, port_a);
	if (conversation != NULL) {
		/*
		 * If this is for a connection-oriented protocol, set the
		 * second address for this conversation to address A, as
		 * that's the address that matched the wildcarded second
		 * address for this conversation, and set the second port
		 * for this conversation to port A, as that's the port
		 * that matched the wildcarded second port for this
		 * conversation.
		 */
		DPRINT(("match found"));
		if (ptype != PT_UDP)
		{
			if(!(conversation->options & CONVERSATION_TEMPLATE))
			{
				conversation_set_addr2(conversation, addr_a);
				conversation_set_port2(conversation, port_a);
			}
			else
			{
				conversation = conversation_create_from_template(conversation, addr_a, port_a);
			}
		}
		return conversation;
	}

	DPRINT(("no matches found"));

	/*
	 * We found no conversation.
	 */
	return NULL;
}

static gint
p_compare(gconstpointer a, gconstpointer b)
{
	const conv_proto_data *ap = (const conv_proto_data *)a;
	const conv_proto_data *bp = (const conv_proto_data *)b;

	if (ap->proto > bp->proto)
		return 1;
	else if (ap->proto == bp->proto)
		return 0;
	else
		return -1;
}

void
conversation_add_proto_data(conversation_t *conv, const int proto, void *proto_data)
{
	conv_proto_data *p1 = wmem_new(wmem_file_scope(), conv_proto_data);

	p1->proto = proto;
	p1->proto_data = proto_data;

	/* Add it to the list of items for this conversation. */

	conv->data_list = g_slist_insert_sorted(conv->data_list, (gpointer *)p1,
	    p_compare);
}

void *
conversation_get_proto_data(const conversation_t *conv, const int proto)
{
	conv_proto_data temp, *p1;
	GSList *item;

	temp.proto = proto;
	temp.proto_data = NULL;

	item = g_slist_find_custom(conv->data_list, (gpointer *)&temp,
	    p_compare);

	if (item != NULL) {
		p1 = (conv_proto_data *)item->data;
		return p1->proto_data;
	}

	return NULL;
}

void
conversation_delete_proto_data(conversation_t *conv, const int proto)
{
	conv_proto_data temp;
	GSList *item;

	temp.proto = proto;
	temp.proto_data = NULL;

	item = g_slist_find_custom(conv->data_list, (gpointer *)&temp,
	    p_compare);

	while(item){
		conv->data_list = g_slist_remove(conv->data_list, item->data);
		item=item->next;
	}
}

void
conversation_set_dissector_from_frame_number(conversation_t *conversation,
	const guint32 starting_frame_num, const dissector_handle_t handle)
{
	wmem_tree_insert32(conversation->dissector_tree, starting_frame_num, (void *)handle);
}

void
conversation_set_dissector(conversation_t *conversation, const dissector_handle_t handle)
{
	conversation_set_dissector_from_frame_number(conversation, 0, handle);
}

dissector_handle_t
conversation_get_dissector(conversation_t *conversation, const guint32 frame_num)
{
	return (dissector_handle_t)wmem_tree_lookup32_le(conversation->dissector_tree, frame_num);
}

/*
 * Given two address/port pairs for a packet, search for a matching
 * conversation and, if found and it has a conversation dissector,
 * call that dissector and return TRUE, otherwise return FALSE.
 *
 * This helper uses call_dissector_only which will NOT call the default
 * "data" dissector if the packet was rejected.
 * Our caller is responsible to call the data dissector explicitly in case
 * this function returns FALSE.
 */
gboolean
try_conversation_dissector(const address *addr_a, const address *addr_b, const port_type ptype,
    const guint32 port_a, const guint32 port_b, tvbuff_t *tvb, packet_info *pinfo,
    proto_tree *tree, void* data)
{
	conversation_t *conversation;

	conversation = find_conversation(pinfo->num, addr_a, addr_b, ptype, port_a,
	    port_b, 0);

	if (conversation != NULL) {
		int ret;
		dissector_handle_t handle = (dissector_handle_t)wmem_tree_lookup32_le(conversation->dissector_tree, pinfo->num);
		if (handle == NULL)
			return FALSE;
		ret=call_dissector_only(handle, tvb, pinfo, tree, data);
		if(!ret) {
			/* this packet was rejected by the dissector
			 * so return FALSE in case our caller wants
			 * to do some cleaning up.
			 */
			return FALSE;
		}
		return TRUE;
	}
	return FALSE;
}

/*  A helper function that calls find_conversation() and, if a conversation is
 *  not found, calls conversation_new().
 *  The frame number and addresses are taken from pinfo.
 *  No options are used, though we could extend this API to include an options
 *  parameter.
 */
conversation_t *
find_or_create_conversation(packet_info *pinfo)
{
	conversation_t *conv=NULL;

	DPRINT(("called for frame #%d: %s:%d -> %s:%d (ptype=%d)",
		pinfo->num, address_to_str(wmem_packet_scope(), &pinfo->src), pinfo->srcport,
		address_to_str(wmem_packet_scope(), &pinfo->dst), pinfo->destport, pinfo->ptype));
	DINDENT();

	/* Have we seen this conversation before? */
	if((conv = find_conversation(pinfo->num, &pinfo->src, &pinfo->dst,
				     pinfo->ptype, pinfo->srcport,
				     pinfo->destport, 0)) != NULL) {
		DPRINT(("found previous conversation for frame #%d (last_frame=%d)",
				pinfo->num, conv->last_frame));
		if (pinfo->num > conv->last_frame) {
			conv->last_frame = pinfo->num;
		}
	} else {
		/* No, this is a new conversation. */
		DPRINT(("did not find previous conversation for frame #%d",
				pinfo->num));
		DINDENT();
		conv = conversation_new(pinfo->num, &pinfo->src,
					&pinfo->dst, pinfo->ptype,
					pinfo->srcport, pinfo->destport, 0);
		DENDENT();
	}

	DENDENT();

	return conv;
}

GHashTable *
get_conversation_hashtable_exact(void)
{
	return conversation_hashtable_exact;
}

GHashTable *
get_conversation_hashtable_no_addr2(void)
{
	return conversation_hashtable_no_addr2;
}

GHashTable *
get_conversation_hashtable_no_port2(void)
{
	return conversation_hashtable_no_port2;
}

GHashTable *
get_conversation_hashtable_no_addr2_or_port2(void)
{
	return conversation_hashtable_no_addr2_or_port2;
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */
