sip_ua_layer.c

一个开源SIP协议栈

/* $Id: sip_ua_layer.c 988 2007-02-20 18:47:12Z bennylp $ */
/* 
 * Copyright (C) 2003-2007 Benny Prijono <[e-mail]>
 *
 * 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 
 */
#include <pjsip/sip_ua_layer.h>
#include <pjsip/sip_module.h>
#include <pjsip/sip_dialog.h>
#include <pjsip/sip_endpoint.h>
#include <pjsip/sip_errno.h>
#include <pjsip/sip_transaction.h>
#include <pj/os.h>
#include <pj/hash.h>
#include <pj/assert.h>
#include <pj/string.h>
#include <pj/pool.h>
#include <pj/log.h>


#define THIS_FILE    "sip_ua_layer.c"

/*
 * Static prototypes.
 */
static pj_status_t mod_ua_load(pjsip_endpoint *endpt);
static pj_status_t mod_ua_unload(void);
static pj_bool_t   mod_ua_on_rx_request(pjsip_rx_data *rdata);
static pj_bool_t   mod_ua_on_rx_response(pjsip_rx_data *rdata);
static void	   mod_ua_on_tsx_state(pjsip_transaction*, pjsip_event*);


extern long pjsip_dlg_lock_tls_id;	/* defined in sip_dialog.c */

/* This struct is used to represent list of dialog inside a dialog set.
 * We don't want to use pjsip_dialog for this purpose, to save some
 * memory (about 100 bytes per dialog set).
 */
struct dlg_set_head
{
    PJ_DECL_LIST_MEMBER(pjsip_dialog);
};

/* This struct represents a dialog set.
 * This is the value that will be put in the UA's hash table.
 */
struct dlg_set
{
    /* To put this node in free dlg_set nodes in UA. */
    PJ_DECL_LIST_MEMBER(struct dlg_set);

    /* This is the buffer to store this entry in the hash table. */
    char ht_entry[PJ_HASH_ENTRY_SIZE];

    /* List of dialog in this dialog set. */
    struct dlg_set_head  dlg_list;
};


/*
 * Module interface.
 */
static struct user_agent
{
    pjsip_module	 mod;
    pj_pool_t		*pool;
    pjsip_endpoint	*endpt;
    pj_mutex_t		*mutex;
    pj_hash_table_t	*dlg_table;
    pjsip_ua_init_param  param;
    struct dlg_set	 free_dlgset_nodes;

} mod_ua = 
{
  {
    NULL, NULL,		    /* prev, next.			*/
    { "mod-ua", 6 },	    /* Name.				*/
    -1,			    /* Id				*/
    PJSIP_MOD_PRIORITY_UA_PROXY_LAYER,	/* Priority		*/
    &mod_ua_load,	    /* load()				*/
    NULL,		    /* start()				*/
    NULL,		    /* stop()				*/
    &mod_ua_unload,	    /* unload()				*/
    &mod_ua_on_rx_request,  /* on_rx_request()			*/
    &mod_ua_on_rx_response, /* on_rx_response()			*/
    NULL,		    /* on_tx_request.			*/
    NULL,		    /* on_tx_response()			*/
    &mod_ua_on_tsx_state,   /* on_tsx_state()			*/
  }
};

/* 
 * mod_ua_load()
 *
 * Called when module is being loaded by endpoint.
 */
static pj_status_t mod_ua_load(pjsip_endpoint *endpt)
{
    pj_status_t status;

    /* Initialize the user agent. */
    mod_ua.endpt = endpt;
    mod_ua.pool = pjsip_endpt_create_pool( endpt, "ua%p", PJSIP_POOL_LEN_UA,
					   PJSIP_POOL_INC_UA);
    if (mod_ua.pool == NULL)
	return PJ_ENOMEM;

    status = pj_mutex_create_recursive(mod_ua.pool, " ua%p", &mod_ua.mutex);
    if (status != PJ_SUCCESS)
	return status;

    mod_ua.dlg_table = pj_hash_create(mod_ua.pool, PJSIP_MAX_DIALOG_COUNT);
    if (mod_ua.dlg_table == NULL)
	return PJ_ENOMEM;

    pj_list_init(&mod_ua.free_dlgset_nodes);

    /* Initialize dialog lock. */
    status = pj_thread_local_alloc(&pjsip_dlg_lock_tls_id);
    if (status != PJ_SUCCESS)
	return status;

    pj_thread_local_set(pjsip_dlg_lock_tls_id, NULL);

    return PJ_SUCCESS;

}

/*
 * mod_ua_unload()
 *
 * Called when module is being unloaded.
 */
static pj_status_t mod_ua_unload(void)
{
    pj_thread_local_free(pjsip_dlg_lock_tls_id);
    pj_mutex_destroy(mod_ua.mutex);

    /* Release pool */
    if (mod_ua.pool) {
	pjsip_endpt_release_pool( mod_ua.endpt, mod_ua.pool );
    }
    return PJ_SUCCESS;
}

/*
 * mod_ua_on_tsx_stats()
 *
 * Called on changed on transaction state.
 */
static void mod_ua_on_tsx_state( pjsip_transaction *tsx, pjsip_event *e)
{
    pjsip_dialog *dlg;

    /* Get the dialog where this transaction belongs. */
    dlg = tsx->mod_data[mod_ua.mod.id];
    
    /* If dialog instance has gone, it could mean that the dialog
     * may has been destroyed.
     */
    if (dlg == NULL)
	return;

    /* Hand over the event to the dialog. */
    pjsip_dlg_on_tsx_state(dlg, tsx, e);
}


/*
 * Init user agent module and register it to the endpoint.
 */
PJ_DEF(pj_status_t) pjsip_ua_init_module( pjsip_endpoint *endpt,
					  const pjsip_ua_init_param *prm)
{
    pj_status_t status;

    /* Check if module already registered. */
    PJ_ASSERT_RETURN(mod_ua.mod.id == -1, PJ_EINVALIDOP);

    /* Copy param, if exists. */
    if (prm)
	pj_memcpy(&mod_ua.param, prm, sizeof(pjsip_ua_init_param));

    /* Register the module. */
    status = pjsip_endpt_register_module(endpt, &mod_ua.mod);

    return status;
}

/*
 * Get the instance of the user agent.
 *
 */
PJ_DEF(pjsip_user_agent*) pjsip_ua_instance(void)
{
    return &mod_ua.mod;
}


/*
 * Get the endpoint where this UA is currently registered.
 */
PJ_DEF(pjsip_endpoint*) pjsip_ua_get_endpt(pjsip_user_agent *ua)
{
    PJ_UNUSED_ARG(ua);
    pj_assert(ua == &mod_ua.mod);
    return mod_ua.endpt;
}


/*
 * Destroy the user agent layer.
 */
PJ_DEF(pj_status_t) pjsip_ua_destroy(void)
{
    /* Check if module already destroyed. */
    PJ_ASSERT_RETURN(mod_ua.mod.id != -1, PJ_EINVALIDOP);

    return pjsip_endpt_unregister_module(mod_ua.endpt, &mod_ua.mod);
}



/*
 * Create key to identify dialog set.
 */
PJ_DEF(void) pjsip_ua_create_dlg_set_key( pj_pool_t *pool,
					  pj_str_t *set_key,
					  const pj_str_t *call_id,
					  const pj_str_t *local_tag)
{
    PJ_ASSERT_ON_FAIL(pool && set_key && call_id && local_tag, return;);

    set_key->slen = call_id->slen + local_tag->slen + 1;
    set_key->ptr = pj_pool_alloc(pool, set_key->slen);
    pj_assert(set_key->ptr != NULL);

    pj_memcpy(set_key->ptr, call_id->ptr, call_id->slen);
    set_key->ptr[call_id->slen] = '$';
    pj_memcpy(set_key->ptr + call_id->slen + 1, 
	      local_tag->ptr, local_tag->slen);
}

/*
 * Acquire one dlg_set node to be put in the hash table.
 * This will first look in the free nodes list, then allocate
 * a new one from UA's pool when one is not available.
 */
static struct dlg_set *alloc_dlgset_node(void)
{
    struct dlg_set *set;

    if (!pj_list_empty(&mod_ua.free_dlgset_nodes)) {
	set = mod_ua.free_dlgset_nodes.next;
	pj_list_erase(set);
	return set;
    } else {
	set = pj_pool_alloc(mod_ua.pool, sizeof(struct dlg_set));
	return set;
    }
}

/*
 * Register new dialog. Called by pjsip_dlg_create_uac() and
 * pjsip_dlg_create_uas();
 */
PJ_DEF(pj_status_t) pjsip_ua_register_dlg( pjsip_user_agent *ua,
					   pjsip_dialog *dlg )
{
    /* Sanity check. */
    PJ_ASSERT_RETURN(ua && dlg, PJ_EINVAL);

    /* For all dialogs, local tag (inc hash) must has been initialized. */
    PJ_ASSERT_RETURN(dlg->local.info && dlg->local.info->tag.slen &&
		     dlg->local.tag_hval != 0, PJ_EBUG);

    /* For UAS dialog, remote tag (inc hash) must have been initialized. */
    //PJ_ASSERT_RETURN(dlg->role==PJSIP_ROLE_UAC ||
    //		     (dlg->role==PJSIP_ROLE_UAS && dlg->remote.info->tag.slen
    //		      && dlg->remote.tag_hval != 0), PJ_EBUG);

    /* Lock the user agent. */
    pj_mutex_lock(mod_ua.mutex);

    /* For UAC, check if there is existing dialog in the same set. */
    if (dlg->role == PJSIP_ROLE_UAC) {
	struct dlg_set *dlg_set;

	dlg_set = pj_hash_get( mod_ua.dlg_table, dlg->local.info->tag.ptr, 
			       dlg->local.info->tag.slen,
			       &dlg->local.tag_hval);

	if (dlg_set) {
	    /* This is NOT the first dialog in the dialog set. 
	     * Just add this dialog in the list.
	     */
	    pj_assert(dlg_set->dlg_list.next != (void*)&dlg_set->dlg_list);
	    pj_list_push_back(&dlg_set->dlg_list, dlg);

	    dlg->dlg_set = dlg_set;

	} else {
	    /* This is the first dialog in the dialog set. 
	     * Create the dialog set and add this dialog to it.
	     */
	    dlg_set = alloc_dlgset_node();
	    pj_list_init(&dlg_set->dlg_list);
	    pj_list_push_back(&dlg_set->dlg_list, dlg);

	    dlg->dlg_set = dlg_set;

	    /* Register the dialog set in the hash table. */
	    pj_hash_set_np(mod_ua.dlg_table, 
			   dlg->local.info->tag.ptr, dlg->local.info->tag.slen,
			   dlg->local.tag_hval, dlg_set->ht_entry, dlg_set);
	}

    } else {
	/* For UAS, create the dialog set with a single dialog as member. */
	struct dlg_set *dlg_set;

	dlg_set = alloc_dlgset_node();
	pj_list_init(&dlg_set->dlg_list);
	pj_list_push_back(&dlg_set->dlg_list, dlg);

	dlg->dlg_set = dlg_set;

	pj_hash_set_np(mod_ua.dlg_table, 
		       dlg->local.info->tag.ptr, dlg->local.info->tag.slen,
		       dlg->local.tag_hval, dlg_set->ht_entry, dlg_set);
    }

    /* Unlock user agent. */
    pj_mutex_unlock(mod_ua.mutex);

    /* Done. */
    return PJ_SUCCESS;
}


PJ_DEF(pj_status_t) pjsip_ua_unregister_dlg( pjsip_user_agent *ua,
					     pjsip_dialog *dlg )
{
    struct dlg_set *dlg_set;
    pjsip_dialog *d;

    /* Sanity-check arguments. */
    PJ_ASSERT_RETURN(ua && dlg, PJ_EINVAL);

    /* Check that dialog has been registered. */
    PJ_ASSERT_RETURN(dlg->dlg_set, PJ_EINVALIDOP);

    /* Lock user agent. */
    pj_mutex_lock(mod_ua.mutex);

    /* Find this dialog from the dialog set. */
    dlg_set = dlg->dlg_set;
    d = dlg_set->dlg_list.next;
    while (d != (pjsip_dialog*)&dlg_set->dlg_list && d != dlg) {
	d = d->next;
    }

    if (d != dlg) {
	pj_assert(!"Dialog is not registered!");
	pj_mutex_unlock(mod_ua.mutex);
	return PJ_EINVALIDOP;
    }

    /* Remove this dialog from the list. */
    pj_list_erase(dlg);

    /* If dialog list is empty, remove the dialog set from the hash table. */
    if (pj_list_empty(&dlg_set->dlg_list)) {
	pj_hash_set(NULL, mod_ua.dlg_table, dlg->local.info->tag.ptr,
		    dlg->local.info->tag.slen, dlg->local.tag_hval, NULL);

	/* Return dlg_set to free nodes. */
	pj_list_push_back(&mod_ua.free_dlgset_nodes, dlg_set);
    }

    /* Unlock user agent. */
    pj_mutex_unlock(mod_ua.mutex);

    /* Done. */
    return PJ_SUCCESS;
}


PJ_DEF(pjsip_dialog*) pjsip_rdata_get_dlg( pjsip_rx_data *rdata )
{
    return rdata->endpt_info.mod_data[mod_ua.mod.id];
}

PJ_DEF(pjsip_dialog*) pjsip_tsx_get_dlg( pjsip_transaction *tsx )
{
    return tsx->mod_data[mod_ua.mod.id];
}


/* 
 * Find a dialog.
 */
PJ_DEF(pjsip_dialog*) pjsip_ua_find_dialog(const pj_str_t *call_id,
					   const pj_str_t *local_tag,
					   const pj_str_t *remote_tag,
					   pj_bool_t lock_dialog)
{
    struct dlg_set *dlg_set;
    pjsip_dialog *dlg;

    PJ_ASSERT_RETURN(call_id && local_tag && remote_tag, NULL);

    /* Lock user agent. */
    pj_mutex_lock(mod_ua.mutex);

    /* Lookup the dialog set. */
    dlg_set = pj_hash_get(mod_ua.dlg_table, local_tag->ptr, local_tag->slen,
			  NULL);
    if (dlg_set == NULL) {
	/* Not found */
	pj_mutex_unlock(mod_ua.mutex);
	return NULL;
    }

    /* Dialog set is found, now find the matching dialog based on the
     * remote tag.
     */
    dlg = dlg_set->dlg_list.next;
    while (dlg != (pjsip_dialog*)&dlg_set->dlg_list) {	
	if (pj_strcmp(&dlg->remote.info->tag, remote_tag) == 0)
	    break;
	dlg = dlg->next;
    }

    if (dlg == (pjsip_dialog*)&dlg_set->dlg_list) {
	/* Not found */
	pj_mutex_unlock(mod_ua.mutex);
	return NULL;
    }

    /* Dialog has been found. It SHOULD have the right Call-ID!! */
    PJ_ASSERT_ON_FAIL(pj_strcmp(&dlg->call_id->id, call_id)==0, 
			{pj_mutex_unlock(mod_ua.mutex); return NULL;});

    if (lock_dialog) {
	if (pjsip_dlg_try_inc_lock(dlg) != PJ_SUCCESS) {

	    /*
	     * Unable to acquire dialog's lock while holding the user
	     * agent's mutex. Release the UA mutex before retrying once
	     * more.
	     *
	     * THIS MAY CAUSE RACE CONDITION!
	     */

	    /* Unlock user agent. */
	    pj_mutex_unlock(mod_ua.mutex);
	    /* Lock dialog */
	    pjsip_dlg_inc_lock(dlg);

	} else {