pjsip_scheduler.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2016, Fairview 5 Engineering, LLC
 *
 * George Joseph <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief res_pjsip Scheduler
 *
 * \author George Joseph <[email protected]>
 */

#include "asterisk.h"

#include "asterisk/res_pjsip.h"
#include "include/res_pjsip_private.h"
#include "asterisk/res_pjsip_cli.h"
#include "asterisk/taskprocessor.h"

#include <regex.h>

#define TASK_BUCKETS 53

static struct ast_sched_context *scheduler_context;
static struct ao2_container *tasks;
static int task_count;

struct ast_sip_sched_task {
   /*! The serializer to be used (if any) (Holds a ref) */
   struct ast_taskprocessor *serializer;
   /*! task data */
   void *task_data;
   /*! task function */
   ast_sip_task task;
   /*! the time the task was originally scheduled/queued */
   struct timeval when_queued;
   /*! the last time the task was started */
   struct timeval last_start;
   /*! the last time the task was ended */
   struct timeval last_end;
   /*! When the periodic task is next expected to run */
   struct timeval next_periodic;
   /*! reschedule interval in milliseconds */
   int interval;
   /*! ast_sched scheudler id */
   int current_scheduler_id;
   /*! task is currently running */
   int is_running;
   /*! times run */
   int run_count;
   /*! the task reschedule, cleanup and policy flags */
   enum ast_sip_scheduler_task_flags flags;
   /*! A name to be associated with the task */
   char name[0];
};

AO2_STRING_FIELD_HASH_FN(ast_sip_sched_task, name);
AO2_STRING_FIELD_CMP_FN(ast_sip_sched_task, name);
AO2_STRING_FIELD_SORT_FN(ast_sip_sched_task, name);

static int push_to_serializer(const void *data);

/*
 * This function is run in the context of the serializer.
 * It runs the task with a simple call and reschedules based on the result.
 */
static int run_task(void *data)
{
   RAII_VAR(struct ast_sip_sched_task *, schtd, data, ao2_cleanup);
   int res;
   int delay;

   if (!schtd->interval) {
      /* Task was cancelled while waiting to be executed by the serializer */
      return -1;
   }

   if (schtd->flags & AST_SIP_SCHED_TASK_TRACK) {
      ast_log(LOG_DEBUG, "Sched %p: Running %s\n", schtd, schtd->name);
   }
   ao2_lock(schtd);
   schtd->last_start = ast_tvnow();
   schtd->is_running = 1;
   ++schtd->run_count;
   ao2_unlock(schtd);

   res = schtd->task(schtd->task_data);

   ao2_lock(schtd);
   schtd->is_running = 0;
   schtd->last_end = ast_tvnow();

   /*
    * Don't restart if the task returned <= 0 or if the interval
    * was set to 0 while the task was running
    */
   if ((schtd->flags & AST_SIP_SCHED_TASK_ONESHOT) || res <= 0 || !schtd->interval) {
      schtd->interval = 0;
      ao2_unlock(schtd);
      ao2_unlink(tasks, schtd);
      return -1;
   }

   if (schtd->flags & AST_SIP_SCHED_TASK_VARIABLE) {
      schtd->interval = res;
   }

   if (schtd->flags & AST_SIP_SCHED_TASK_DELAY) {
      delay = schtd->interval;
   } else {
      int64_t diff;

      /* Determine next periodic interval we need to expire. */
      do {
         schtd->next_periodic = ast_tvadd(schtd->next_periodic,
            ast_samp2tv(schtd->interval, 1000));
         diff = ast_tvdiff_ms(schtd->next_periodic, schtd->last_end);
      } while (diff <= 0);
      delay = diff;
   }

   schtd->current_scheduler_id = ast_sched_add(scheduler_context, delay, push_to_serializer, schtd);
   if (schtd->current_scheduler_id < 0) {
      schtd->interval = 0;
      ao2_unlock(schtd);
      ast_log(LOG_ERROR, "Sched %p: Failed to reschedule task %s\n", schtd, schtd->name);
      ao2_unlink(tasks, schtd);
      return -1;
   }

   ao2_unlock(schtd);
   if (schtd->flags & AST_SIP_SCHED_TASK_TRACK) {
      ast_log(LOG_DEBUG, "Sched %p: Rescheduled %s for %d ms\n", schtd, schtd->name,
         delay);
   }

   return 0;
}

/*
 * This function is run by the scheduler thread.  Its only job is to push the task
 * to the serialize and return.  It returns 0 so it's not rescheduled.
 */
static int push_to_serializer(const void *data)
{
   struct ast_sip_sched_task *schtd = (struct ast_sip_sched_task *)data;
   int sched_id;

   ao2_lock(schtd);
   sched_id = schtd->current_scheduler_id;
   schtd->current_scheduler_id = -1;
   ao2_unlock(schtd);
   if (sched_id < 0) {
      /* Task was cancelled while waiting on the lock */
      return 0;
   }

   if (schtd->flags & AST_SIP_SCHED_TASK_TRACK) {
      ast_log(LOG_DEBUG, "Sched %p: Ready to run %s\n", schtd, schtd->name);
   }
   ao2_t_ref(schtd, +1, "Give ref to run_task()");
   if (ast_sip_push_task(schtd->serializer, run_task, schtd)) {
      /*
       * Oh my.  Have to cancel the scheduled item because we
       * unexpectedly cannot run it anymore.
       */
      ao2_unlink(tasks, schtd);
      ao2_lock(schtd);
      schtd->interval = 0;
      ao2_unlock(schtd);

      ao2_t_ref(schtd, -1, "Failed so release run_task() ref");
   }

   return 0;
}

int ast_sip_sched_task_cancel(struct ast_sip_sched_task *schtd)
{
   int res;
   int sched_id;

   if (schtd->flags & AST_SIP_SCHED_TASK_TRACK) {
      ast_log(LOG_DEBUG, "Sched %p: Canceling %s\n", schtd, schtd->name);
   }

   /*
    * Prevent any tasks in the serializer queue from
    * running and restarting the scheduled item on us
    * first.
    */
   ao2_lock(schtd);
   schtd->interval = 0;

   sched_id = schtd->current_scheduler_id;
   schtd->current_scheduler_id = -1;
   ao2_unlock(schtd);
   res = ast_sched_del(scheduler_context, sched_id);

   ao2_unlink(tasks, schtd);

   return res;
}

int ast_sip_sched_task_cancel_by_name(const char *name)
{
   int res;
   struct ast_sip_sched_task *schtd;

   if (ast_strlen_zero(name)) {
      return -1;
   }

   schtd = ao2_find(tasks, name, OBJ_SEARCH_KEY);
   if (!schtd) {
      return -1;
   }

   res = ast_sip_sched_task_cancel(schtd);
   ao2_ref(schtd, -1);
   return res;
}

int ast_sip_sched_task_get_times2(struct ast_sip_sched_task *schtd,
   struct timeval *queued, struct timeval *last_start, struct timeval *last_end,
   int *interval, int *time_left, struct timeval *next_start)
{
   ao2_lock(schtd);
   if (queued) {
      memcpy(queued, &schtd->when_queued, sizeof(struct timeval));
   }
   if (last_start) {
      memcpy(last_start, &schtd->last_start, sizeof(struct timeval));
   }
   if (last_end) {
      memcpy(last_end, &schtd->last_end, sizeof(struct timeval));
   }

   if (interval) {
      *interval = schtd->interval;
   }

   if (time_left || next_start) {
      int delay;
      struct timeval since_when;
      struct timeval now;
      struct timeval next;

      if (schtd->interval) {
         delay = schtd->interval;
         now = ast_tvnow();

         if (schtd->flags & AST_SIP_SCHED_TASK_DELAY) {
            since_when = schtd->is_running ? now : schtd->last_end;
         } else {
            since_when = schtd->last_start.tv_sec ? schtd->last_start : schtd->when_queued;
         }

         delay -= ast_tvdiff_ms(now, since_when);

         delay = delay < 0 ? 0 : delay;


         if (time_left) {
            *time_left = delay;
         }

         if (next_start) {
            next = ast_tvadd(now, ast_tv(delay / 1000, (delay % 1000) * 1000));
            memcpy(next_start, &next, sizeof(struct timeval));
         }
      } else {
         if (time_left) {
            *time_left = -1;
         }
      }

   }

   ao2_unlock(schtd);

   return 0;
}


int ast_sip_sched_task_get_times(struct ast_sip_sched_task *schtd,
   struct timeval *queued, struct timeval *last_start, struct timeval *last_end)
{
   return ast_sip_sched_task_get_times2(schtd, queued, last_start, last_end, NULL, NULL, NULL);
}

int ast_sip_sched_task_get_times_by_name2(const char *name,
   struct timeval *queued, struct timeval *last_start, struct timeval *last_end,
   int *interval, int *time_left, struct timeval *next_start)
{
   int res;
   struct ast_sip_sched_task *schtd;

   if (ast_strlen_zero(name)) {
      return -1;
   }

   schtd = ao2_find(tasks, name, OBJ_SEARCH_KEY);
   if (!schtd) {
      return -1;
   }

   res = ast_sip_sched_task_get_times2(schtd, queued, last_start, last_end, interval, time_left,
      next_start);
   ao2_ref(schtd, -1);
   return res;
}

int ast_sip_sched_task_get_times_by_name(const char *name,
   struct timeval *queued, struct timeval *last_start, struct timeval *last_end)
{
   return ast_sip_sched_task_get_times_by_name2(name, queued, last_start, last_end,
      NULL, NULL, NULL);
}

int ast_sip_sched_task_get_name(struct ast_sip_sched_task *schtd, char *name, size_t maxlen)
{
   if (maxlen <= 0) {
      return -1;
   }

   ao2_lock(schtd);
   ast_copy_string(name, schtd->name, maxlen);
   ao2_unlock(schtd);

   return 0;
}

int ast_sip_sched_task_get_next_run(struct ast_sip_sched_task *schtd)
{
   int delay;

   ast_sip_sched_task_get_times2(schtd, NULL, NULL, NULL, NULL, &delay, NULL);

   return delay;
}

int ast_sip_sched_task_get_next_run_by_name(const char *name)
{
   int next_run;
   struct ast_sip_sched_task *schtd;

   if (ast_strlen_zero(name)) {
      return -1;
   }

   schtd = ao2_find(tasks, name, OBJ_SEARCH_KEY);
   if (!schtd) {
      return -1;
   }

   next_run = ast_sip_sched_task_get_next_run(schtd);
   ao2_ref(schtd, -1);
   return next_run;
}

int ast_sip_sched_is_task_running(struct ast_sip_sched_task *schtd)
{
   return schtd ? schtd->is_running : 0;
}

int ast_sip_sched_is_task_running_by_name(const char *name)
{
   int is_running;
   struct ast_sip_sched_task *schtd;

   if (ast_strlen_zero(name)) {
      return 0;
   }

   schtd = ao2_find(tasks, name, OBJ_SEARCH_KEY);
   if (!schtd) {
      return 0;
   }

   is_running = schtd->is_running;
   ao2_ref(schtd, -1);
   return is_running;
}

static void schtd_dtor(void *data)
{
   struct ast_sip_sched_task *schtd = data;

   if (schtd->flags & AST_SIP_SCHED_TASK_TRACK) {
      ast_log(LOG_DEBUG, "Sched %p: Destructor %s\n", schtd, schtd->name);
   }
   if (schtd->flags & AST_SIP_SCHED_TASK_DATA_AO2) {
      /* release our own ref, then release the callers if asked to do so */
      ao2_ref(schtd->task_data, (schtd->flags & AST_SIP_SCHED_TASK_DATA_FREE) ? -2 : -1);
   } else if (schtd->task_data && (schtd->flags & AST_SIP_SCHED_TASK_DATA_FREE)) {
      ast_free(schtd->task_data);
   }
   ast_taskprocessor_unreference(schtd->serializer);
}

struct ast_sip_sched_task *ast_sip_schedule_task(struct ast_taskprocessor *serializer,
   int interval, ast_sip_task sip_task, const char *name, void *task_data,
   enum ast_sip_scheduler_task_flags flags)
{
#define ID_LEN 13 /* task_deadbeef */
   struct ast_sip_sched_task *schtd;
   int res;

   if (interval <= 0) {
      return NULL;
   }

   schtd = ao2_alloc((sizeof(*schtd) + (!ast_strlen_zero(name) ? strlen(name) : ID_LEN) + 1),
      schtd_dtor);
   if (!schtd) {
      return NULL;
   }

   schtd->serializer = ao2_bump(serializer);
   schtd->task_data = task_data;
   schtd->task = sip_task;
   schtd->interval = interval;
   schtd->flags = flags;
   schtd->last_start = ast_tv(0, 0);
   if (!ast_strlen_zero(name)) {
      strcpy(schtd->name, name); /* Safe */
   } else {
      uint32_t task_id;

      task_id = ast_atomic_fetchadd_int(&task_count, 1);
      sprintf(schtd->name, "task_%08x", task_id);
   }
   if (schtd->flags & AST_SIP_SCHED_TASK_TRACK) {
      ast_log(LOG_DEBUG, "Sched %p: Scheduling %s for %d ms\n", schtd, schtd->name,
         interval);
   }
   schtd->when_queued = ast_tvnow();
   if (!(schtd->flags & AST_SIP_SCHED_TASK_DELAY)) {
      schtd->next_periodic = ast_tvadd(schtd->when_queued,
         ast_samp2tv(schtd->interval, 1000));
   }

   if (flags & AST_SIP_SCHED_TASK_DATA_AO2) {
      ao2_ref(task_data, +1);
   }

   /*
    * We must put it in the 'tasks' container before scheduling
    * the task because we don't want the push_to_serializer()
    * sched task to "remove" it on failure before we even put
    * it in.  If this happens then nothing would remove it from
    * the 'tasks' container.
    */
   ao2_link(tasks, schtd);

   /*
    * Lock so we are guaranteed to get the sched id set before
    * the push_to_serializer() sched task can clear it.
    */
   ao2_lock(schtd);
   res = ast_sched_add(scheduler_context, interval, push_to_serializer, schtd);
   schtd->current_scheduler_id = res;
   ao2_unlock(schtd);
   if (res < 0) {
      ao2_unlink(tasks, schtd);
      ao2_ref(schtd, -1);
      return NULL;
   }

   return schtd;
#undef ID_LEN
}

#define TIME_FORMAT "%a %T"

static char *cli_show_tasks(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ao2_iterator iter;
   struct ao2_container *sorted_tasks;
   struct ast_sip_sched_task *schtd;
   struct ast_tm tm;
   char times_run[16];
   char queued[32];
   char last_start[32];
   char next_start[32];
   struct timeval now;
   int using_regex = 0;
   regex_t regex;

   switch (cmd) {
   case CLI_INIT:
      e->command = "pjsip show scheduled_tasks";
      e->usage = "Usage: pjsip show scheduled_tasks [ like <pattern> ]\n"
                  "      Show scheduled pjsip tasks\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (a->argc != 3 && a->argc != 5) {
      return CLI_SHOWUSAGE;
   }

   if (a->argc == 5) {
      int regrc;
      if (strcasecmp(a->argv[3], "like")) {
         return CLI_SHOWUSAGE;
      }
      regrc = regcomp(&regex, a->argv[4], REG_EXTENDED | REG_ICASE | REG_NOSUB);
      if (regrc) {
         char err[256];
         regerror(regrc, &regex, err, 256);
         ast_cli(a->fd, "PJSIP Scheduled Tasks: Error: %s\n", err);
         return CLI_FAILURE;
      }
      using_regex = 1;
   }

   /* Get a sorted snapshot of the scheduled tasks */
   sorted_tasks = ao2_container_alloc_rbtree(AO2_ALLOC_OPT_LOCK_NOLOCK, 0,
      ast_sip_sched_task_sort_fn, NULL);
   if (!sorted_tasks) {
      ast_cli(a->fd, "PJSIP Scheduled Tasks: Unable to allocate temporary container\n");
      return CLI_FAILURE;
   }
   if (ao2_container_dup(sorted_tasks, tasks, 0)) {
      ao2_ref(sorted_tasks, -1);
      ast_cli(a->fd, "PJSIP Scheduled Tasks: Unable to sort temporary container\n");
      return CLI_FAILURE;
   }

   now = ast_tvnow();

   ast_localtime(&now, &tm, NULL);

   ast_cli(a->fd, "PJSIP Scheduled Tasks:\n\n");

   ast_cli(a->fd,
      "<Task Name....................................> <Interval> <Times Run> <State>"
      "  <Queued....>  <Last Start>  <Next Start.....secs>\n"
      "=============================================================================="
      "===================================================\n");

   iter = ao2_iterator_init(sorted_tasks, AO2_ITERATOR_UNLINK);
   for (; (schtd = ao2_iterator_next(&iter)); ao2_ref(schtd, -1)) {
      int next_run_sec;
      struct timeval next;

      ao2_lock(schtd);

      if (using_regex && regexec(&regex, schtd->name, 0, NULL, 0) == REG_NOMATCH) {
         ao2_unlock(schtd);
         continue;
      }

      next_run_sec = ast_sip_sched_task_get_next_run(schtd) / 1000;
      if (next_run_sec < 0) {
         /* Scheduled task is now canceled */
         ao2_unlock(schtd);
         continue;
      }
      next = ast_tvadd(now, ast_tv(next_run_sec, 0));

      ast_localtime(&schtd->when_queued, &tm, NULL);
      ast_strftime(queued, sizeof(queued), TIME_FORMAT, &tm);

      ast_localtime(&schtd->last_start, &tm, NULL);
      ast_strftime(last_start, sizeof(last_start), TIME_FORMAT, &tm);

      ast_localtime(&next, &tm, NULL);
      ast_strftime(next_start, sizeof(next_start), TIME_FORMAT, &tm);

      sprintf(times_run, "%d", schtd->run_count);

      ast_cli(a->fd, "%-46.46s   %9d   %9s   %-5s  %-12s  %-12s  %-12s %8d\n",
         schtd->name,
         schtd->interval / 1000,
         schtd->flags & AST_SIP_SCHED_TASK_ONESHOT ? "oneshot" : times_run,
         schtd->is_running ? "run" : "wait",
         queued,
         (ast_tvzero(schtd->last_start) || (schtd->flags & AST_SIP_SCHED_TASK_ONESHOT) ? "" : last_start),
         next_start,
         next_run_sec);
      ao2_unlock(schtd);
   }
   if (using_regex) {
      regfree(&regex);
   }
   ao2_iterator_destroy(&iter);
   ast_cli(a->fd, "\nTotal Scheduled Tasks: %d\n\n", ao2_container_count(sorted_tasks));
   ao2_ref(sorted_tasks, -1);

   return CLI_SUCCESS;
}

static struct ast_cli_entry cli_commands[] = {
   AST_CLI_DEFINE(cli_show_tasks, "Show pjsip scheduled tasks"),
};

int ast_sip_initialize_scheduler(void)
{
   scheduler_context = ast_sched_context_create();
   if (!scheduler_context) {
      ast_log(LOG_ERROR, "Failed to create scheduler. Aborting load\n");
      return -1;
   }

   if (ast_sched_start_thread(scheduler_context)) {
      ast_log(LOG_ERROR, "Failed to start scheduler. Aborting load\n");
      ast_sched_context_destroy(scheduler_context);
      return -1;
   }

   tasks = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_RWLOCK,
      AO2_CONTAINER_ALLOC_OPT_DUPS_REJECT, TASK_BUCKETS, ast_sip_sched_task_hash_fn,
      ast_sip_sched_task_sort_fn, ast_sip_sched_task_cmp_fn);
   if (!tasks) {
      ast_log(LOG_ERROR, "Failed to allocate task container. Aborting load\n");
      ast_sched_context_destroy(scheduler_context);
      return -1;
   }

   ast_cli_register_multiple(cli_commands, ARRAY_LEN(cli_commands));

   return 0;
}

int ast_sip_destroy_scheduler(void)
{
   ast_cli_unregister_multiple(cli_commands, ARRAY_LEN(cli_commands));

   if (scheduler_context) {
      if (tasks) {
         struct ao2_iterator iter;
         struct ast_sip_sched_task *schtd;

         /* Cancel all scheduled tasks */
         iter = ao2_iterator_init(tasks, 0);
         while ((schtd = ao2_iterator_next(&iter))) {
            ast_sip_sched_task_cancel(schtd);
            ao2_ref(schtd, -1);
         }
         ao2_iterator_destroy(&iter);
      }

      ast_sched_context_destroy(scheduler_context);
      scheduler_context = NULL;
   }

   ao2_cleanup(tasks);
   tasks = NULL;

   return 0;
}