wireshark/conversation.c

294 lines
8.0 KiB
C

/* conversation.c
* Routines for building lists of packets that are part of a "conversation"
*
* $Id: conversation.c,v 1.7 2000/04/12 22:53:14 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.org>
* Copyright 1998 Gerald Combs
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#include <string.h>
#include <glib.h>
#include "packet.h"
#include "conversation.h"
static GHashTable *conversation_hashtable = NULL;
static GMemChunk *conversation_key_chunk = NULL;
static GMemChunk *conversation_chunk = NULL;
typedef struct conversation_key {
struct conversation_key *next;
address src;
address dst;
port_type ptype;
guint32 port_src;
guint32 port_dst;
} conversation_key;
/*
* 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;
static int conversation_init_count = 200;
/*
* Compare two conversation keys.
*/
static gint
conversation_equal(gconstpointer v, gconstpointer w)
{
conversation_key *v1 = (conversation_key *)v;
conversation_key *v2 = (conversation_key *)w;
if (v1->ptype != v2->ptype)
return 0; /* different types of port */
/*
* Are the first and second source ports the same, the first and
* second destination ports the same, the first and second source
* addresses the same, and the first and second destination
* addresses the same?
*/
if (v1->port_src == v2->port_src &&
v1->port_dst == v2->port_dst &&
v1->src.type == v2->src.type &&
v1->src.len == v2->src.len &&
memcmp(v1->src.data, v2->src.data, v1->src.len) == 0 &&
v1->dst.type == v2->dst.type &&
v1->dst.len == v2->dst.len &&
memcmp(v1->dst.data, v2->dst.data, v1->dst.len) == 0) {
/*
* Yes. It's the same conversation, and the two
* address/port pairs are going in the same direction.
*/
return 1;
}
/*
* Is the first source port the same as the second destination
* port, the first destination port the same as the first
* source port, the first source address the same as the second
* destination address, and the first destination address the
* same as the second source address?
*/
if (v1->port_src == v2->port_dst &&
v1->port_dst == v2->port_src &&
v1->src.type == v2->dst.type &&
v1->src.len == v2->dst.len &&
memcmp(v1->src.data, v2->dst.data, v1->src.len) == 0 &&
v1->dst.type == v2->src.type &&
v1->dst.len == v2->src.len &&
memcmp(v1->dst.data, v2->src.data, v1->dst.len) == 0) {
/*
* 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 a given set of source and destination
* addresses and ports.
*/
static guint
conversation_hash(gconstpointer v)
{
conversation_key *key = (conversation_key *)v;
guint hash_val;
int i;
hash_val = 0;
for (i = 0; i < key->src.len; i++)
hash_val += key->src.data[i];
for (i = 0; i < key->dst.len; i++)
hash_val += key->dst.data[i];
hash_val += key->port_src + key->port_dst;
return hash_val;
}
/*
* Initialize some variables every time a file is loaded or re-loaded.
* Destroy all existing conversations, and create a new hash table
* for the conversations in the new file.
*/
void
conversation_init(void)
{
conversation_key *key;
/*
* Free the addresses associated with the conversation keys.
*/
for (key = conversation_keys; key != NULL; key = key->next) {
/*
* Grr. I guess the theory here is that freeing
* something sure as heck modifies it, so you
* want to ban attempts to free it, but, alas,
* if we make the "data" field of an "address"
* structure not a "const", the compiler whines if
* we try to make it point into the data for a packet,
* as that's a "const" array (and should be, as dissectors
* shouldn't trash it).
*
* So we cast the complaint into oblivion, and rely on
* the fact that these addresses are known to have had
* their data mallocated, i.e. they don't point into,
* say, the middle of the data for a packet.
*/
g_free((gpointer)key->src.data);
g_free((gpointer)key->dst.data);
}
conversation_keys = NULL;
if (conversation_hashtable != NULL)
g_hash_table_destroy(conversation_hashtable);
if (conversation_key_chunk != NULL)
g_mem_chunk_destroy(conversation_key_chunk);
if (conversation_chunk != NULL)
g_mem_chunk_destroy(conversation_chunk);
conversation_hashtable = g_hash_table_new(conversation_hash,
conversation_equal);
conversation_key_chunk = g_mem_chunk_new("conversation_key_chunk",
sizeof(conversation_key),
conversation_init_count * sizeof(struct conversation_key),
G_ALLOC_AND_FREE);
conversation_chunk = g_mem_chunk_new("conversation_chunk",
sizeof(conversation_t),
conversation_init_count * sizeof(conversation_t),
G_ALLOC_AND_FREE);
/*
* Start the conversation indices over at 0.
*/
new_index = 0;
}
/*
* Copy an address, allocating a new buffer for the address data.
*/
static void
copy_address(address *to, address *from)
{
guint8 *data;
to->type = from->type;
to->len = from->len;
data = g_malloc(from->len);
memcpy(data, from->data, from->len);
to->data = data;
}
/*
* Given source and destination addresses and ports for a packet,
* create a new conversation to contain packets between those address/port
* pairs.
*/
conversation_t *
conversation_new(address *src, address *dst, port_type ptype,
guint32 src_port, guint32 dst_port, void *data)
{
conversation_t *conversation;
conversation_key *new_key;
new_key = g_mem_chunk_alloc(conversation_key_chunk);
new_key->next = conversation_keys;
conversation_keys = new_key;
copy_address(&new_key->src, src);
copy_address(&new_key->dst, dst);
new_key->ptype = ptype;
new_key->port_src = src_port;
new_key->port_dst = dst_port;
conversation = g_mem_chunk_alloc(conversation_chunk);
conversation->index = new_index;
conversation->data = data;
/* clear dissector pointer */
conversation->dissector = NULL;
new_index++;
g_hash_table_insert(conversation_hashtable, new_key, conversation);
return conversation;
}
/*
* Given source and destination addresses and ports for a packet,
* search for a conversation containing packets between those address/port
* pairs. Returns NULL if not found.
*/
conversation_t *
find_conversation(address *src, address *dst, port_type ptype,
guint32 src_port, guint32 dst_port)
{
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.src = *src;
key.dst = *dst;
key.ptype = ptype;
key.port_src = src_port;
key.port_dst = dst_port;
return g_hash_table_lookup(conversation_hashtable, &key);
}
/*
* Given source and destination addresses and ports for a packet,
* search for a conversational dissector.
* Returns NULL if not found.
*/
dissector_t find_conversation_dissector(address *src, address *dst, port_type ptype,
guint32 src_port, guint32 dst_port){
conversation_t *conversation = find_conversation(src, dst, ptype, src_port, dst_port);
if ( conversation)
return conversation->dissector;
return NULL;
}