dlg_timer.c

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/*
 * Copyright (C) 2006 Voice System SRL
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio 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
 *
 * Kamailio 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
 *
 * History:
 * --------
 * 2006-04-14  initial version (bogdan)
 * 2007-03-06  to avoid races, tests on timer links are done under locks
 *             (bogdan)
 */

#include "../../mem/shm_mem.h"
#include "../../timer.h"
#include "dlg_timer.h"

struct dlg_timer *d_timer = 0;
dlg_timer_handler timer_hdl = 0;


int init_dlg_timer(dlg_timer_handler hdl)
{
        d_timer = (struct dlg_timer*)shm_malloc(sizeof(struct dlg_timer));
        if (d_timer==0) {
                LM_ERR("no more shm mem\n");
                return -1;
        }
        memset( d_timer, 0, sizeof(struct dlg_timer) );

        d_timer->first.next = d_timer->first.prev = &(d_timer->first);

        d_timer->lock = lock_alloc();
        if (d_timer->lock==0) {
                LM_ERR("failed to alloc lock\n");
                goto error0;
        }

        if (lock_init(d_timer->lock)==0) {
                LM_ERR("failed to init lock\n");
                goto error1;
        }

        timer_hdl = hdl;
        return 0;
error1:
        lock_dealloc(d_timer->lock);
error0:
        shm_free(d_timer);
        d_timer = 0;
        return -1;
}


void destroy_dlg_timer(void)
{
        if (d_timer==0)
                return;

        lock_destroy(d_timer->lock);
        lock_dealloc(d_timer->lock);

        shm_free(d_timer);
        d_timer = 0;
}


static inline void insert_dialog_timer_unsafe(struct dlg_tl *tl)
{
        struct dlg_tl* ptr;

        /* insert in sorted order */
        for(ptr = d_timer->first.prev; ptr != &d_timer->first ; ptr = ptr->prev) {
                if ( ptr->timeout <= tl->timeout )
                        break;
        }

        LM_DBG("inserting %p for %d\n", tl,tl->timeout);
        tl->prev = ptr;
        tl->next = ptr->next;
        tl->prev->next = tl;
        tl->next->prev = tl;
}


int insert_dlg_timer(struct dlg_tl *tl, int interval)
{
        lock_get( d_timer->lock);

        if (tl->next!=0 || tl->prev!=0) {
                LM_CRIT("Trying to insert a bogus dlg tl=%p tl->next=%p tl->prev=%p\n",
                        tl, tl->next, tl->prev);
                lock_release( d_timer->lock);
                return -1;
        }
        tl->timeout = get_ticks()+interval;
        insert_dialog_timer_unsafe( tl );

        lock_release( d_timer->lock);

        return 0;
}


static inline void remove_dialog_timer_unsafe(struct dlg_tl *tl)
{
        tl->prev->next = tl->next;
        tl->next->prev = tl->prev;
}


int remove_dialog_timer(struct dlg_tl *tl)
{
        lock_get( d_timer->lock);

        if (tl->prev==NULL && tl->timeout==0) {
                lock_release( d_timer->lock);
                return 1;
        }

        if (tl->prev==NULL || tl->next==NULL) {
                LM_CRIT("bogus tl=%p tl->prev=%p tl->next=%p\n",
                        tl, tl->prev, tl->next);
                lock_release( d_timer->lock);
                return -1;
        }

        remove_dialog_timer_unsafe(tl);
        tl->next = NULL;
        tl->prev = NULL;
        tl->timeout = 0;

        lock_release( d_timer->lock);
        return 0;
}


int update_dlg_timer(struct dlg_tl *tl, int timeout)
{
        lock_get( d_timer->lock);

        if (tl->next==0 || tl->prev==0) {
                LM_CRIT("Trying to update a bogus dlg tl=%p tl->next=%p tl->prev=%p\n",
                        tl, tl->next, tl->prev);
                lock_release( d_timer->lock);
                return -1;
        }
        remove_dialog_timer_unsafe( tl );
        tl->timeout = get_ticks()+timeout;
        insert_dialog_timer_unsafe( tl );

        lock_release( d_timer->lock);
        return 0;
}


static inline struct dlg_tl* get_expired_dlgs(unsigned int time)
{
        struct dlg_tl *tl , *end, *ret;

        lock_get( d_timer->lock);

        if (d_timer->first.next==&(d_timer->first)
        || d_timer->first.next->timeout > time ) {
                lock_release( d_timer->lock);
                return 0;
        }

        end = &d_timer->first;
        tl = d_timer->first.next;
        LM_DBG("start with tl=%p tl->prev=%p tl->next=%p (%d) at %d "
                "and end with end=%p end->prev=%p end->next=%p\n",
                tl,tl->prev,tl->next,tl->timeout,time,
                end,end->prev,end->next);
        while( tl!=end && tl->timeout <= time) {
                LM_DBG("getting tl=%p tl->prev=%p tl->next=%p with %d\n",
                        tl,tl->prev,tl->next,tl->timeout);
                tl->prev = 0;
                tl->timeout = 0;
                tl=tl->next;
        }
        LM_DBG("end with tl=%p tl->prev=%p tl->next=%p and d_timer->first.next->prev=%p\n",
                tl,tl->prev,tl->next,d_timer->first.next->prev);

        if (tl==end && d_timer->first.next->prev) {
                ret = 0;
        } else {
                ret = d_timer->first.next;
                tl->prev->next = 0;
                d_timer->first.next = tl;
                tl->prev = &d_timer->first;
        }

        lock_release( d_timer->lock);

        return ret;
}


void dlg_timer_routine(unsigned int ticks , void * attr)
{
        struct dlg_tl *tl, *ctl;

        tl = get_expired_dlgs( ticks );

        while (tl) {
                ctl = tl;
                tl = tl->next;
                ctl->next = NULL;
                LM_DBG("tl=%p next=%p\n", ctl, tl);
                timer_hdl( ctl );
        }
}