res/res_pjsip_keepalive.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 2014, Digium, Inc.
   5  *
   6  * Joshua Colp <jcolp@digium.com>
   7  *
   8  * See http://www.asterisk.org for more information about
   9  * the Asterisk project. Please do not directly contact
  10  * any of the maintainers of this project for assistance;
  11  * the project provides a web site, mailing lists and IRC
  12  * channels for your use.
  13  *
  14  * This program is free software, distributed under the terms of
  15  * the GNU General Public License Version 2. See the LICENSE file
  16  * at the top of the source tree.
  17  */
  18
  19 /*** MODULEINFO
  20         <depend>pjproject</depend>
  21         <depend>res_pjsip</depend>
  22         <support_level>core</support_level>
  23  ***/
  24
  25 #include "asterisk.h"
  26
  27 #include <pjsip.h>
  28 #include <pjsip_ua.h>
  29
  30 #include "asterisk/res_pjsip.h"
  31 #include "asterisk/module.h"
  32 #include "asterisk/astobj2.h"
  33
  34 /*! \brief Number of buckets for keepalive transports */
  35 #define KEEPALIVE_TRANSPORTS_BUCKETS 53
  36
  37 /*! \brief The keep alive packet to send */
  38 static const pj_str_t keepalive_packet = { "\r\n\r\n", 4 };
  39
  40 /*! \brief Global container of active transports */
  41 static struct ao2_container *transports;
  42
  43 /*! \brief Thread keeping things alive */
  44 static pthread_t keepalive_thread = AST_PTHREADT_NULL;
  45
  46 /*! \brief The global interval at which to send keepalives */
  47 static unsigned int keepalive_interval;
  48
  49 /*! \brief Existing transport manager callback that we need to invoke */
  50 static pjsip_tp_state_callback tpmgr_state_callback;
  51
  52 /*! \brief Structure for transport to be kept alive */
  53 struct keepalive_transport {
  54         /*! \brief The underlying PJSIP transport */
  55         pjsip_transport *transport;
  56 };
  57
  58 /*! \brief Callback function to send keepalive */
  59 static int keepalive_transport_cb(void *obj, void *arg, int flags)
  60 {
  61         struct keepalive_transport *keepalive = obj;
  62         pjsip_tpselector selector = {
  63                 .type = PJSIP_TPSELECTOR_TRANSPORT,
  64                 .u.transport = keepalive->transport,
  65         };
  66
  67         pjsip_tpmgr_send_raw(pjsip_endpt_get_tpmgr(ast_sip_get_pjsip_endpoint()),
  68                 keepalive->transport->key.type, &selector, NULL, keepalive_packet.ptr, keepalive_packet.slen,
  69                 &keepalive->transport->key.rem_addr, pj_sockaddr_get_len(&keepalive->transport->key.rem_addr),
  70                 NULL, NULL);
  71
  72         return 0;
  73 }
  74
  75 /*! \brief Thread which sends keepalives to all active connection-oriented transports */
  76 static void *keepalive_transport_thread(void *data)
  77 {
  78         pj_thread_desc desc;
  79         pj_thread_t *thread;
  80
  81         if (pj_thread_register("Asterisk Keepalive Thread", desc, &thread) != PJ_SUCCESS) {
  82                 ast_log(LOG_ERROR, "Could not register keepalive thread with PJLIB, keepalives will not occur.\n");
  83                 return NULL;
  84         }
  85
  86         /* Once loaded this module just keeps on going as it is unsafe to stop and change the underlying
  87          * callback for the transport manager.
  88          */
  89         while (1) {
  90                 sleep(keepalive_interval);
  91                 ao2_callback(transports, OBJ_NODATA, keepalive_transport_cb, NULL);
  92         }
  93
  94         return NULL;
  95 }
  96
  97 /*! \brief Destructor for keepalive transport */
  98 static void keepalive_transport_destroy(void *obj)
  99 {
 100         struct keepalive_transport *keepalive = obj;
 101
 102         pjsip_transport_dec_ref(keepalive->transport);
 103 }
 104
 105 /*! \brief Callback invoked when transport changes occur */
 106 static void keepalive_transport_state_callback(pjsip_transport *transport, pjsip_transport_state state,
 107         const pjsip_transport_state_info *info)
 108 {
 109         /* We only care about connection-oriented transports */
 110         if (transport->flag & PJSIP_TRANSPORT_RELIABLE) {
 111                 struct keepalive_transport *keepalive;
 112
 113                 switch (state) {
 114                 case PJSIP_TP_STATE_CONNECTED:
 115                         keepalive = ao2_alloc(sizeof(*keepalive), keepalive_transport_destroy);
 116                         if (keepalive) {
 117                                 keepalive->transport = transport;
 118                                 pjsip_transport_add_ref(keepalive->transport);
 119                                 ao2_link(transports, keepalive);
 120                                 ao2_ref(keepalive, -1);
 121                         }
 122                         break;
 123                 case PJSIP_TP_STATE_DISCONNECTED:
 124                         ao2_find(transports, transport->obj_name, OBJ_SEARCH_KEY | OBJ_NODATA | OBJ_UNLINK);
 125                         break;
 126                 default:
 127                         break;
 128                 }
 129         }
 130
 131         /* Forward to the old state callback if present */
 132         if (tpmgr_state_callback) {
 133                 tpmgr_state_callback(transport, state, info);
 134         }
 135 }
 136
 137 /*! \brief Hashing function for keepalive transport */
 138 static int keepalive_transport_hash_fn(const void *obj, int flags)
 139 {
 140         const struct keepalive_transport *object;
 141         const char *key;
 142
 143         switch (flags & OBJ_SEARCH_MASK) {
 144         case OBJ_SEARCH_KEY:
 145                 key = obj;
 146                 break;
 147         case OBJ_SEARCH_OBJECT:
 148                 object = obj;
 149                 key = object->transport->obj_name;
 150                 break;
 151         default:
 152                 /* Hash can only work on something with a full key. */
 153                 ast_assert(0);
 154                 return 0;
 155         }
 156         return ast_str_hash(key);
 157 }
 158
 159 /*! \brief Comparison function for keepalive transport */
 160 static int keepalive_transport_cmp_fn(void *obj, void *arg, int flags)
 161 {
 162         const struct keepalive_transport *object_left = obj;
 163         const struct keepalive_transport *object_right = arg;
 164         const char *right_key = arg;
 165         int cmp;
 166
 167         switch (flags & OBJ_SEARCH_MASK) {
 168         case OBJ_SEARCH_OBJECT:
 169                 right_key = object_right->transport->obj_name;
 170                 /* Fall through */
 171         case OBJ_SEARCH_KEY:
 172                 cmp = strcmp(object_left->transport->obj_name, right_key);
 173                 break;
 174         case OBJ_SEARCH_PARTIAL_KEY:
 175                 /*
 176                  * We could also use a partial key struct containing a length
 177                  * so strlen() does not get called for every comparison instead.
 178                  */
 179                 cmp = strncmp(object_left->transport->obj_name, right_key, strlen(right_key));
 180                 break;
 181         default:
 182                 /*
 183                  * What arg points to is specific to this traversal callback
 184                  * and has no special meaning to astobj2.
 185                  */
 186                 cmp = 0;
 187                 break;
 188         }
 189
 190         return !cmp ? CMP_MATCH | CMP_STOP : 0;
 191 }
 192
 193 static void keepalive_global_loaded(const char *object_type)
 194 {
 195         unsigned int new_interval = ast_sip_get_keep_alive_interval();
 196         pjsip_tpmgr *tpmgr;
 197
 198         if (new_interval) {
 199                 keepalive_interval = new_interval;
 200         } else if (keepalive_interval) {
 201                 ast_log(LOG_NOTICE, "Keepalive support can not be disabled once activated.\n");
 202                 return;
 203         } else {
 204                 /* This will occur if no keepalive interval has been specified at initial start */
 205                 return;
 206         }
 207
 208         if (keepalive_thread != AST_PTHREADT_NULL) {
 209                 return;
 210         }
 211
 212         transports = ao2_container_alloc(KEEPALIVE_TRANSPORTS_BUCKETS, keepalive_transport_hash_fn,
 213                 keepalive_transport_cmp_fn);
 214         if (!transports) {
 215                 ast_log(LOG_ERROR, "Could not create container for transports to perform keepalive on.\n");
 216                 return;
 217         }
 218
 219         tpmgr = pjsip_endpt_get_tpmgr(ast_sip_get_pjsip_endpoint());
 220         if (!tpmgr) {
 221                 ast_log(LOG_ERROR, "No transport manager to attach keepalive functionality to.\n");
 222                 ao2_ref(transports, -1);
 223                 return;
 224         }
 225
 226         if (ast_pthread_create(&keepalive_thread, NULL, keepalive_transport_thread, NULL)) {
 227                 ast_log(LOG_ERROR, "Could not create thread for sending keepalive messages.\n");
 228                 ao2_ref(transports, -1);
 229                 return;
 230         }
 231
 232         tpmgr_state_callback = pjsip_tpmgr_get_state_cb(tpmgr);
 233         pjsip_tpmgr_set_state_cb(tpmgr, &keepalive_transport_state_callback);
 234 }
 235
 236 /*! \brief Observer which is used to update our interval when the global setting changes */
 237 static struct ast_sorcery_observer keepalive_global_observer = {
 238         .loaded = keepalive_global_loaded,
 239 };
 240
 241 static int load_module(void)
 242 {
 243         ast_sorcery_observer_add(ast_sip_get_sorcery(), "global", &keepalive_global_observer);
 244         ast_sorcery_reload_object(ast_sip_get_sorcery(), "global");
 245         ast_module_ref(ast_module_info->self);
 246         return AST_MODULE_LOAD_SUCCESS;
 247 }
 248
 249 static int unload_module(void)
 250 {
 251         /* This will never get called */
 252         return 0;
 253 }
 254
 255 static int reload_module(void)
 256 {
 257         ast_sorcery_reload_object(ast_sip_get_sorcery(), "global");
 258         return 0;
 259 }
 260
 261 AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Stateful Connection Keepalive Support",
 262                 .support_level = AST_MODULE_SUPPORT_CORE,
 263                 .load = load_module,
 264                 .reload = reload_module,
 265                 .unload = unload_module,
 266                 .load_pri = AST_MODPRI_CHANNEL_DEPEND - 4,
 267                    );