Mon Mar 19 11:30:23 2012

Asterisk developer's documentation


bridging.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 2007 - 2009, Digium, Inc.
00005  *
00006  * Joshua Colp <jcolp@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  *
00021  * \brief Channel Bridging API
00022  *
00023  * \author Joshua Colp <jcolp@digium.com>
00024  */
00025 
00026 #include "asterisk.h"
00027 
00028 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 319920 $")
00029 
00030 #include <signal.h>
00031 
00032 #include "asterisk/logger.h"
00033 #include "asterisk/channel.h"
00034 #include "asterisk/options.h"
00035 #include "asterisk/utils.h"
00036 #include "asterisk/lock.h"
00037 #include "asterisk/linkedlists.h"
00038 #include "asterisk/bridging.h"
00039 #include "asterisk/bridging_technology.h"
00040 #include "asterisk/app.h"
00041 #include "asterisk/file.h"
00042 #include "asterisk/module.h"
00043 #include "asterisk/astobj2.h"
00044 
00045 static AST_RWLIST_HEAD_STATIC(bridge_technologies, ast_bridge_technology);
00046 
00047 /* Initial starting point for the bridge array of channels */
00048 #define BRIDGE_ARRAY_START 128
00049 
00050 /* Grow rate of bridge array of channels */
00051 #define BRIDGE_ARRAY_GROW 32
00052 
00053 /*! Default DTMF keys for built in features */
00054 static char builtin_features_dtmf[AST_BRIDGE_BUILTIN_END][MAXIMUM_DTMF_FEATURE_STRING];
00055 
00056 /*! Function handlers for the built in features */
00057 static void *builtin_features_handlers[AST_BRIDGE_BUILTIN_END];
00058 
00059 int __ast_bridge_technology_register(struct ast_bridge_technology *technology, struct ast_module *module)
00060 {
00061    struct ast_bridge_technology *current = NULL;
00062 
00063    /* Perform a sanity check to make sure the bridge technology conforms to our needed requirements */
00064    if (ast_strlen_zero(technology->name) || !technology->capabilities || !technology->write) {
00065       ast_log(LOG_WARNING, "Bridge technology %s failed registration sanity check.\n", technology->name);
00066       return -1;
00067    }
00068 
00069    AST_RWLIST_WRLOCK(&bridge_technologies);
00070 
00071    /* Look for duplicate bridge technology already using this name, or already registered */
00072    AST_RWLIST_TRAVERSE(&bridge_technologies, current, entry) {
00073       if ((!strcasecmp(current->name, technology->name)) || (current == technology)) {
00074          ast_log(LOG_WARNING, "A bridge technology of %s already claims to exist in our world.\n", technology->name);
00075          AST_RWLIST_UNLOCK(&bridge_technologies);
00076          return -1;
00077       }
00078    }
00079 
00080    /* Copy module pointer so reference counting can keep the module from unloading */
00081    technology->mod = module;
00082 
00083    /* Insert our new bridge technology into the list and print out a pretty message */
00084    AST_RWLIST_INSERT_TAIL(&bridge_technologies, technology, entry);
00085 
00086    AST_RWLIST_UNLOCK(&bridge_technologies);
00087 
00088    if (option_verbose > 1) {
00089       ast_verbose(VERBOSE_PREFIX_2 "Registered bridge technology %s\n", technology->name);
00090    }
00091 
00092    return 0;
00093 }
00094 
00095 int ast_bridge_technology_unregister(struct ast_bridge_technology *technology)
00096 {
00097    struct ast_bridge_technology *current = NULL;
00098 
00099    AST_RWLIST_WRLOCK(&bridge_technologies);
00100 
00101    /* Ensure the bridge technology is registered before removing it */
00102    AST_RWLIST_TRAVERSE_SAFE_BEGIN(&bridge_technologies, current, entry) {
00103       if (current == technology) {
00104          AST_RWLIST_REMOVE_CURRENT(entry);
00105          if (option_verbose > 1) {
00106             ast_verbose(VERBOSE_PREFIX_2 "Unregistered bridge technology %s\n", technology->name);
00107          }
00108          break;
00109       }
00110    }
00111    AST_RWLIST_TRAVERSE_SAFE_END;
00112 
00113    AST_RWLIST_UNLOCK(&bridge_technologies);
00114 
00115    return current ? 0 : -1;
00116 }
00117 
00118 void ast_bridge_change_state(struct ast_bridge_channel *bridge_channel, enum ast_bridge_channel_state new_state)
00119 {
00120    /* Change the state on the bridge channel */
00121    bridge_channel->state = new_state;
00122 
00123    /* Only poke the channel's thread if it is not us */
00124    if (!pthread_equal(pthread_self(), bridge_channel->thread)) {
00125       pthread_kill(bridge_channel->thread, SIGURG);
00126       ast_mutex_lock(&bridge_channel->lock);
00127       ast_cond_signal(&bridge_channel->cond);
00128       ast_mutex_unlock(&bridge_channel->lock);
00129    }
00130 
00131    return;
00132 }
00133 
00134 /*! \brief Helper function to poke the bridge thread */
00135 static void bridge_poke(struct ast_bridge *bridge)
00136 {
00137    /* Poke the thread just in case */
00138    if (bridge->thread != AST_PTHREADT_NULL && bridge->thread != AST_PTHREADT_STOP) {
00139       pthread_kill(bridge->thread, SIGURG);
00140    }
00141 
00142    return;
00143 }
00144 
00145 /*! \brief Helper function to add a channel to the bridge array
00146  *
00147  * \note This function assumes the bridge is locked.
00148  */
00149 static void bridge_array_add(struct ast_bridge *bridge, struct ast_channel *chan)
00150 {
00151    /* We have to make sure the bridge thread is not using the bridge array before messing with it */
00152    while (bridge->waiting) {
00153       bridge_poke(bridge);
00154       sched_yield();
00155    }
00156 
00157    bridge->array[bridge->array_num++] = chan;
00158 
00159    ast_debug(1, "Added channel %s(%p) to bridge array on %p, new count is %d\n", chan->name, chan, bridge, (int)bridge->array_num);
00160 
00161    /* If the next addition of a channel will exceed our array size grow it out */
00162    if (bridge->array_num == bridge->array_size) {
00163       struct ast_channel **tmp;
00164       ast_debug(1, "Growing bridge array on %p from %d to %d\n", bridge, (int)bridge->array_size, (int)bridge->array_size + BRIDGE_ARRAY_GROW);
00165       if (!(tmp = ast_realloc(bridge->array, (bridge->array_size + BRIDGE_ARRAY_GROW) * sizeof(struct ast_channel *)))) {
00166          ast_log(LOG_ERROR, "Failed to allocate more space for another channel on bridge '%p', this is not going to end well\n", bridge);
00167          return;
00168       }
00169       bridge->array = tmp;
00170       bridge->array_size += BRIDGE_ARRAY_GROW;
00171    }
00172 
00173    return;
00174 }
00175 
00176 /*! \brief Helper function to remove a channel from the bridge array
00177  *
00178  * \note This function assumes the bridge is locked.
00179  */
00180 static void bridge_array_remove(struct ast_bridge *bridge, struct ast_channel *chan)
00181 {
00182    int i;
00183 
00184    /* We have to make sure the bridge thread is not using the bridge array before messing with it */
00185    while (bridge->waiting) {
00186       bridge_poke(bridge);
00187       sched_yield();
00188    }
00189 
00190    for (i = 0; i < bridge->array_num; i++) {
00191       if (bridge->array[i] == chan) {
00192          bridge->array[i] = (bridge->array[(bridge->array_num - 1)] != chan ? bridge->array[(bridge->array_num - 1)] : NULL);
00193          bridge->array[(bridge->array_num - 1)] = NULL;
00194          bridge->array_num--;
00195          ast_debug(1, "Removed channel %p from bridge array on %p, new count is %d\n", chan, bridge, (int)bridge->array_num);
00196          break;
00197       }
00198    }
00199 
00200    return;
00201 }
00202 
00203 /*! \brief Helper function to find a bridge channel given a channel */
00204 static struct ast_bridge_channel *find_bridge_channel(struct ast_bridge *bridge, struct ast_channel *chan)
00205 {
00206    struct ast_bridge_channel *bridge_channel = NULL;
00207 
00208    AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
00209       if (bridge_channel->chan == chan) {
00210          break;
00211       }
00212    }
00213 
00214    return bridge_channel;
00215 }
00216 
00217 /*! \brief Internal function to see whether a bridge should dissolve, and if so do it */
00218 static void bridge_check_dissolve(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
00219 {
00220    struct ast_bridge_channel *bridge_channel2 = NULL;
00221 
00222    if (!ast_test_flag(&bridge->feature_flags, AST_BRIDGE_FLAG_DISSOLVE) && (!bridge_channel->features || !bridge_channel->features->usable || !ast_test_flag(&bridge_channel->features->feature_flags, AST_BRIDGE_FLAG_DISSOLVE))) {
00223       return;
00224    }
00225 
00226    ast_debug(1, "Dissolving bridge %p\n", bridge);
00227 
00228    AST_LIST_TRAVERSE(&bridge->channels, bridge_channel2, entry) {
00229       if (bridge_channel2->state != AST_BRIDGE_CHANNEL_STATE_END && bridge_channel2->state != AST_BRIDGE_CHANNEL_STATE_DEPART) {
00230          ast_bridge_change_state(bridge_channel2, AST_BRIDGE_CHANNEL_STATE_HANGUP);
00231       }
00232    }
00233 
00234    /* Since all the channels are going away let's go ahead and stop our on thread */
00235    bridge->stop = 1;
00236 
00237    return;
00238 }
00239 
00240 /*! \brief Internal function to handle DTMF from a channel */
00241 static struct ast_frame *bridge_handle_dtmf(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
00242 {
00243    struct ast_bridge_features *features = (bridge_channel->features ? bridge_channel->features : &bridge->features);
00244    struct ast_bridge_features_hook *hook = NULL;
00245 
00246    /* If the features structure we grabbed is not usable immediately return the frame */
00247    if (!features->usable) {
00248       return frame;
00249    }
00250 
00251    /* See if this DTMF matches the beginnings of any feature hooks, if so we switch to the feature state to either execute the feature or collect more DTMF */
00252    AST_LIST_TRAVERSE(&features->hooks, hook, entry) {
00253       if (hook->dtmf[0] == frame->subclass.integer) {
00254          ast_frfree(frame);
00255          frame = NULL;
00256          ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_FEATURE);
00257          break;
00258       }
00259    }
00260 
00261    return frame;
00262 }
00263 
00264 /*! \brief Internal function used to determine whether a control frame should be dropped or not */
00265 static int bridge_drop_control_frame(int subclass)
00266 {
00267    switch (subclass) {
00268    case AST_CONTROL_ANSWER:
00269    case -1:
00270       return 1;
00271    default:
00272       return 0;
00273    }
00274 }
00275 
00276 void ast_bridge_handle_trip(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_channel *chan, int outfd)
00277 {
00278    /* If no bridge channel has been provided and the actual channel has been provided find it */
00279    if (chan && !bridge_channel) {
00280       bridge_channel = find_bridge_channel(bridge, chan);
00281    }
00282 
00283    /* If a bridge channel with actual channel is present read a frame and handle it */
00284    if (chan && bridge_channel) {
00285       struct ast_frame *frame = (((bridge->features.mute) || (bridge_channel->features && bridge_channel->features->mute)) ? ast_read_noaudio(chan) : ast_read(chan));
00286 
00287       /* This is pretty simple... see if they hung up */
00288       if (!frame || (frame->frametype == AST_FRAME_CONTROL && frame->subclass.integer == AST_CONTROL_HANGUP)) {
00289          /* Signal the thread that is handling the bridged channel that it should be ended */
00290          ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_END);
00291       } else if (frame->frametype == AST_FRAME_CONTROL && bridge_drop_control_frame(frame->subclass.integer)) {
00292          ast_debug(1, "Dropping control frame from bridge channel %p\n", bridge_channel);
00293       } else {
00294          if (frame->frametype == AST_FRAME_DTMF_BEGIN) {
00295             frame = bridge_handle_dtmf(bridge, bridge_channel, frame);
00296          }
00297          /* Simply write the frame out to the bridge technology if it still exists */
00298          if (frame) {
00299             bridge->technology->write(bridge, bridge_channel, frame);
00300          }
00301       }
00302 
00303       if (frame) {
00304          ast_frfree(frame);
00305       }
00306       return;
00307    }
00308 
00309    /* If a file descriptor actually tripped pass it off to the bridge technology */
00310    if (outfd > -1 && bridge->technology->fd) {
00311       bridge->technology->fd(bridge, bridge_channel, outfd);
00312       return;
00313    }
00314 
00315    /* If all else fails just poke the bridge */
00316    if (bridge->technology->poke && bridge_channel) {
00317       bridge->technology->poke(bridge, bridge_channel);
00318       return;
00319    }
00320 
00321    return;
00322 }
00323 
00324 /*! \brief Generic thread loop, TODO: Rethink this/improve it */
00325 static int generic_thread_loop(struct ast_bridge *bridge)
00326 {
00327    while (!bridge->stop && !bridge->refresh && bridge->array_num) {
00328       struct ast_channel *winner = NULL;
00329       int to = -1;
00330 
00331       /* Move channels around for priority reasons if we have more than one channel in our array */
00332       if (bridge->array_num > 1) {
00333          struct ast_channel *first = bridge->array[0];
00334          memmove(bridge->array, bridge->array + 1, sizeof(struct ast_channel *) * (bridge->array_num - 1));
00335          bridge->array[(bridge->array_num - 1)] = first;
00336       }
00337 
00338       /* Wait on the channels */
00339       bridge->waiting = 1;
00340       ao2_unlock(bridge);
00341       winner = ast_waitfor_n(bridge->array, (int)bridge->array_num, &to);
00342       bridge->waiting = 0;
00343       ao2_lock(bridge);
00344 
00345       /* Process whatever they did */
00346       ast_bridge_handle_trip(bridge, NULL, winner, -1);
00347    }
00348 
00349    return 0;
00350 }
00351 
00352 /*! \brief Bridge thread function */
00353 static void *bridge_thread(void *data)
00354 {
00355    struct ast_bridge *bridge = data;
00356    int res = 0;
00357 
00358    ao2_lock(bridge);
00359 
00360    ast_debug(1, "Started bridge thread for %p\n", bridge);
00361 
00362    /* Loop around until we are told to stop */
00363    while (!bridge->stop && bridge->array_num && !res) {
00364       /* In case the refresh bit was set simply set it back to off */
00365       bridge->refresh = 0;
00366 
00367       ast_debug(1, "Launching bridge thread function %p for bridge %p\n", (bridge->technology->thread ? bridge->technology->thread : &generic_thread_loop), bridge);
00368 
00369       /* Execute the appropriate thread function. If the technology does not provide one we use the generic one */
00370       res = (bridge->technology->thread ? bridge->technology->thread(bridge) : generic_thread_loop(bridge));
00371    }
00372 
00373    ast_debug(1, "Ending bridge thread for %p\n", bridge);
00374 
00375    /* Indicate the bridge thread is no longer active */
00376    bridge->thread = AST_PTHREADT_NULL;
00377    ao2_unlock(bridge);
00378 
00379    ao2_ref(bridge, -1);
00380 
00381    return NULL;
00382 }
00383 
00384 /*! \brief Helper function used to find the "best" bridge technology given a specified capabilities */
00385 static struct ast_bridge_technology *find_best_technology(enum ast_bridge_capability capabilities)
00386 {
00387    struct ast_bridge_technology *current = NULL, *best = NULL;
00388 
00389    AST_RWLIST_RDLOCK(&bridge_technologies);
00390    AST_RWLIST_TRAVERSE(&bridge_technologies, current, entry) {
00391       ast_debug(1, "Bridge technology %s has capabilities %d and we want %d\n", current->name, current->capabilities, capabilities);
00392       if (current->suspended) {
00393          ast_debug(1, "Bridge technology %s is suspended. Skipping.\n", current->name);
00394          continue;
00395       }
00396       if (!(current->capabilities & capabilities)) {
00397          ast_debug(1, "Bridge technology %s does not have the capabilities we need.\n", current->name);
00398          continue;
00399       }
00400       if (best && best->preference < current->preference) {
00401          ast_debug(1, "Bridge technology %s has preference %d while %s has preference %d. Skipping.\n", current->name, current->preference, best->name, best->preference);
00402          continue;
00403       }
00404       best = current;
00405    }
00406 
00407    if (best) {
00408       /* Increment it's module reference count if present so it does not get unloaded while in use */
00409       if (best->mod) {
00410          ast_module_ref(best->mod);
00411       }
00412       ast_debug(1, "Chose bridge technology %s\n", best->name);
00413    }
00414 
00415    AST_RWLIST_UNLOCK(&bridge_technologies);
00416 
00417    return best;
00418 }
00419 
00420 static void destroy_bridge(void *obj)
00421 {
00422    struct ast_bridge *bridge = obj;
00423 
00424    ast_debug(1, "Actually destroying bridge %p, nobody wants it anymore\n", bridge);
00425 
00426    /* Pass off the bridge to the technology to destroy if needed */
00427    if (bridge->technology->destroy) {
00428       ast_debug(1, "Giving bridge technology %s the bridge structure %p to destroy\n", bridge->technology->name, bridge);
00429       if (bridge->technology->destroy(bridge)) {
00430          ast_debug(1, "Bridge technology %s failed to destroy bridge structure %p... trying our best\n", bridge->technology->name, bridge);
00431       }
00432    }
00433 
00434    /* We are no longer using the bridge technology so decrement the module reference count on it */
00435    if (bridge->technology->mod) {
00436       ast_module_unref(bridge->technology->mod);
00437    }
00438 
00439    /* Last but not least clean up the features configuration */
00440    ast_bridge_features_cleanup(&bridge->features);
00441 
00442    /* Drop the array of channels */
00443    ast_free(bridge->array);
00444 
00445    return;
00446 }
00447 
00448 struct ast_bridge *ast_bridge_new(enum ast_bridge_capability capabilities, int flags)
00449 {
00450    struct ast_bridge *bridge = NULL;
00451    struct ast_bridge_technology *bridge_technology = NULL;
00452 
00453    /* If we need to be a smart bridge see if we can move between 1to1 and multimix bridges */
00454    if (flags & AST_BRIDGE_FLAG_SMART) {
00455       struct ast_bridge *other_bridge;
00456 
00457       if (!(other_bridge = ast_bridge_new((capabilities & AST_BRIDGE_CAPABILITY_1TO1MIX) ? AST_BRIDGE_CAPABILITY_MULTIMIX : AST_BRIDGE_CAPABILITY_1TO1MIX, 0))) {
00458          return NULL;
00459       }
00460 
00461       ast_bridge_destroy(other_bridge);
00462    }
00463 
00464    /* If capabilities were provided use our helper function to find the "best" bridge technology, otherwise we can
00465     * just look for the most basic capability needed, single 1to1 mixing. */
00466    bridge_technology = (capabilities ? find_best_technology(capabilities) : find_best_technology(AST_BRIDGE_CAPABILITY_1TO1MIX));
00467 
00468    /* If no bridge technology was found we can't possibly do bridging so fail creation of the bridge */
00469    if (!bridge_technology) {
00470       ast_debug(1, "Failed to find a bridge technology to satisfy capabilities %d\n", capabilities);
00471       return NULL;
00472    }
00473 
00474    /* We have everything we need to create this bridge... so allocate the memory, link things together, and fire her up! */
00475    if (!(bridge = ao2_alloc(sizeof(*bridge), destroy_bridge))) {
00476       return NULL;
00477    }
00478 
00479    bridge->technology = bridge_technology;
00480    bridge->thread = AST_PTHREADT_NULL;
00481 
00482    /* Create an array of pointers for the channels that will be joining us */
00483    bridge->array = ast_calloc(BRIDGE_ARRAY_START, sizeof(struct ast_channel*));
00484    bridge->array_size = BRIDGE_ARRAY_START;
00485 
00486    ast_set_flag(&bridge->feature_flags, flags);
00487 
00488    /* Pass off the bridge to the technology to manipulate if needed */
00489    if (bridge->technology->create) {
00490       ast_debug(1, "Giving bridge technology %s the bridge structure %p to setup\n", bridge->technology->name, bridge);
00491       if (bridge->technology->create(bridge)) {
00492          ast_debug(1, "Bridge technology %s failed to setup bridge structure %p\n", bridge->technology->name, bridge);
00493          ao2_ref(bridge, -1);
00494          bridge = NULL;
00495       }
00496    }
00497 
00498    return bridge;
00499 }
00500 
00501 int ast_bridge_check(enum ast_bridge_capability capabilities)
00502 {
00503    struct ast_bridge_technology *bridge_technology = NULL;
00504 
00505    if (!(bridge_technology = find_best_technology(capabilities))) {
00506       return 0;
00507    }
00508 
00509    ast_module_unref(bridge_technology->mod);
00510 
00511    return 1;
00512 }
00513 
00514 int ast_bridge_destroy(struct ast_bridge *bridge)
00515 {
00516    struct ast_bridge_channel *bridge_channel = NULL;
00517 
00518    ao2_lock(bridge);
00519 
00520    bridge->stop = 1;
00521 
00522    bridge_poke(bridge);
00523 
00524    ast_debug(1, "Telling all channels in bridge %p to end and leave the party\n", bridge);
00525 
00526    /* Drop every bridged channel, the last one will cause the bridge thread (if it exists) to exit */
00527    AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
00528       ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_END);
00529    }
00530 
00531    ao2_unlock(bridge);
00532 
00533    ao2_ref(bridge, -1);
00534 
00535    return 0;
00536 }
00537 
00538 static int bridge_make_compatible(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
00539 {
00540    format_t formats[2] = {bridge_channel->chan->readformat, bridge_channel->chan->writeformat};
00541 
00542    /* Are the formats currently in use something ths bridge can handle? */
00543    if (!(bridge->technology->formats & bridge_channel->chan->readformat)) {
00544       format_t best_format = ast_best_codec(bridge->technology->formats);
00545 
00546       /* Read format is a no go... */
00547       if (option_debug) {
00548          char codec_buf[512];
00549          ast_debug(1, "Bridge technology %s wants to read any of formats %s but channel has %s\n", bridge->technology->name,
00550             ast_getformatname_multiple(codec_buf, sizeof(codec_buf), bridge->technology->formats),
00551             ast_getformatname(formats[0]));
00552       }
00553       /* Switch read format to the best one chosen */
00554       if (ast_set_read_format(bridge_channel->chan, best_format)) {
00555          ast_log(LOG_WARNING, "Failed to set channel %s to read format %s\n", bridge_channel->chan->name, ast_getformatname(best_format));
00556          return -1;
00557       }
00558       ast_debug(1, "Bridge %p put channel %s into read format %s\n", bridge, bridge_channel->chan->name, ast_getformatname(best_format));
00559    } else {
00560       ast_debug(1, "Bridge %p is happy that channel %s already has read format %s\n", bridge, bridge_channel->chan->name, ast_getformatname(formats[0]));
00561    }
00562 
00563    if (!(bridge->technology->formats & formats[1])) {
00564       int best_format = ast_best_codec(bridge->technology->formats);
00565 
00566       /* Write format is a no go... */
00567       if (option_debug) {
00568          char codec_buf[512];
00569          ast_debug(1, "Bridge technology %s wants to write any of formats %s but channel has %s\n", bridge->technology->name,
00570             ast_getformatname_multiple(codec_buf, sizeof(codec_buf), bridge->technology->formats),
00571             ast_getformatname(formats[1]));
00572       }
00573       /* Switch write format to the best one chosen */
00574       if (ast_set_write_format(bridge_channel->chan, best_format)) {
00575          ast_log(LOG_WARNING, "Failed to set channel %s to write format %s\n", bridge_channel->chan->name, ast_getformatname(best_format));
00576          return -1;
00577       }
00578       ast_debug(1, "Bridge %p put channel %s into write format %s\n", bridge, bridge_channel->chan->name, ast_getformatname(best_format));
00579    } else {
00580       ast_debug(1, "Bridge %p is happy that channel %s already has write format %s\n", bridge, bridge_channel->chan->name, ast_getformatname(formats[1]));
00581    }
00582 
00583    return 0;
00584 }
00585 
00586 /*! \brief Perform the smart bridge operation. Basically sees if a new bridge technology should be used instead of the current one. */
00587 static int smart_bridge_operation(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, int count)
00588 {
00589    enum ast_bridge_capability new_capabilities = 0;
00590    struct ast_bridge_technology *new_technology = NULL, *old_technology = bridge->technology;
00591    struct ast_bridge temp_bridge = {
00592       .technology = bridge->technology,
00593       .bridge_pvt = bridge->bridge_pvt,
00594    };
00595    struct ast_bridge_channel *bridge_channel2 = NULL;
00596 
00597    /* Based on current feature determine whether we want to change bridge technologies or not */
00598    if (bridge->technology->capabilities & AST_BRIDGE_CAPABILITY_1TO1MIX) {
00599       if (count <= 2) {
00600          ast_debug(1, "Bridge %p channel count (%d) is within limits for bridge technology %s, not performing smart bridge operation.\n", bridge, count, bridge->technology->name);
00601          return 0;
00602       }
00603       new_capabilities = AST_BRIDGE_CAPABILITY_MULTIMIX;
00604    } else if (bridge->technology->capabilities & AST_BRIDGE_CAPABILITY_MULTIMIX) {
00605       if (count > 2) {
00606          ast_debug(1, "Bridge %p channel count (%d) is within limits for bridge technology %s, not performing smart bridge operation.\n", bridge, count, bridge->technology->name);
00607          return 0;
00608       }
00609       new_capabilities = AST_BRIDGE_CAPABILITY_1TO1MIX;
00610    }
00611 
00612    if (!new_capabilities) {
00613       ast_debug(1, "Bridge '%p' has no new capabilities, not performing smart bridge operation.\n", bridge);
00614       return 0;
00615    }
00616 
00617    /* Attempt to find a new bridge technology to satisfy the capabilities */
00618    if (!(new_technology = find_best_technology(new_capabilities))) {
00619       ast_debug(1, "Smart bridge operation was unable to find new bridge technology with capabilities %d to satisfy bridge %p\n", new_capabilities, bridge);
00620       return -1;
00621    }
00622 
00623    ast_debug(1, "Performing smart bridge operation on bridge %p, moving from bridge technology %s to %s\n", bridge, old_technology->name, new_technology->name);
00624 
00625    /* If a thread is currently executing for the current technology tell it to stop */
00626    if (bridge->thread != AST_PTHREADT_NULL) {
00627       /* If the new bridge technology also needs a thread simply tell the bridge thread to refresh itself. This has the benefit of not incurring the cost/time of tearing down and bringing up a new thread. */
00628       if (new_technology->capabilities & AST_BRIDGE_CAPABILITY_THREAD) {
00629          ast_debug(1, "Telling current bridge thread for bridge %p to refresh\n", bridge);
00630          bridge->refresh = 1;
00631          bridge_poke(bridge);
00632       } else {
00633          pthread_t bridge_thread = bridge->thread;
00634          ast_debug(1, "Telling current bridge thread for bridge %p to stop\n", bridge);
00635          bridge->stop = 1;
00636          bridge_poke(bridge);
00637          ao2_unlock(bridge);
00638          pthread_join(bridge_thread, NULL);
00639          ao2_lock(bridge);
00640       }
00641    }
00642 
00643    /* Since we are soon going to pass this bridge to a new technology we need to NULL out the bridge_pvt pointer but don't worry as it still exists in temp_bridge, ditto for the old technology */
00644    bridge->bridge_pvt = NULL;
00645    bridge->technology = new_technology;
00646 
00647    /* Pass the bridge to the new bridge technology so it can set it up */
00648    if (new_technology->create) {
00649       ast_debug(1, "Giving bridge technology %s the bridge structure %p to setup\n", new_technology->name, bridge);
00650       if (new_technology->create(bridge)) {
00651          ast_debug(1, "Bridge technology %s failed to setup bridge structure %p\n", new_technology->name, bridge);
00652       }
00653    }
00654 
00655    /* Move existing channels over to the new technology, while taking them away from the old one */
00656    AST_LIST_TRAVERSE(&bridge->channels, bridge_channel2, entry) {
00657       /* Skip over channel that initiated the smart bridge operation */
00658       if (bridge_channel == bridge_channel2) {
00659          continue;
00660       }
00661 
00662       /* First we part them from the old technology */
00663       if (old_technology->leave) {
00664          ast_debug(1, "Giving bridge technology %s notification that %p is leaving bridge %p (really %p)\n", old_technology->name, bridge_channel2, &temp_bridge, bridge);
00665          if (old_technology->leave(&temp_bridge, bridge_channel2)) {
00666             ast_debug(1, "Bridge technology %s failed to allow %p (really %p) to leave bridge %p\n", old_technology->name, bridge_channel2, &temp_bridge, bridge);
00667          }
00668       }
00669 
00670       /* Second we make them compatible again with the bridge */
00671       bridge_make_compatible(bridge, bridge_channel2);
00672 
00673       /* Third we join them to the new technology */
00674       if (new_technology->join) {
00675          ast_debug(1, "Giving bridge technology %s notification that %p is joining bridge %p\n", new_technology->name, bridge_channel2, bridge);
00676          if (new_technology->join(bridge, bridge_channel2)) {
00677             ast_debug(1, "Bridge technology %s failed to join %p to bridge %p\n", new_technology->name, bridge_channel2, bridge);
00678          }
00679       }
00680 
00681       /* Fourth we tell them to wake up so they become aware that they above has happened */
00682       pthread_kill(bridge_channel2->thread, SIGURG);
00683       ast_mutex_lock(&bridge_channel2->lock);
00684       ast_cond_signal(&bridge_channel2->cond);
00685       ast_mutex_unlock(&bridge_channel2->lock);
00686    }
00687 
00688    /* Now that all the channels have been moved over we need to get rid of all the information the old technology may have left around */
00689    if (old_technology->destroy) {
00690       ast_debug(1, "Giving bridge technology %s the bridge structure %p (really %p) to destroy\n", old_technology->name, &temp_bridge, bridge);
00691       if (old_technology->destroy(&temp_bridge)) {
00692          ast_debug(1, "Bridge technology %s failed to destroy bridge structure %p (really %p)... some memory may have leaked\n", old_technology->name, &temp_bridge, bridge);
00693       }
00694    }
00695 
00696    /* Finally if the old technology has module referencing remove our reference, we are no longer going to use it */
00697    if (old_technology->mod) {
00698       ast_module_unref(old_technology->mod);
00699    }
00700 
00701    return 0;
00702 }
00703 
00704 /*! \brief Run in a multithreaded model. Each joined channel does writing/reading in their own thread. TODO: Improve */
00705 static enum ast_bridge_channel_state bridge_channel_join_multithreaded(struct ast_bridge_channel *bridge_channel)
00706 {
00707    int fds[4] = { -1, }, nfds = 0, i = 0, outfd = -1, ms = -1;
00708    struct ast_channel *chan = NULL;
00709 
00710    /* Add any file descriptors we may want to monitor */
00711    if (bridge_channel->bridge->technology->fd) {
00712       for (i = 0; i < 4; i ++) {
00713          if (bridge_channel->fds[i] >= 0) {
00714             fds[nfds++] = bridge_channel->fds[i];
00715          }
00716       }
00717    }
00718 
00719    ao2_unlock(bridge_channel->bridge);
00720 
00721    /* Wait for data to either come from the channel or us to be signalled */
00722    if (!bridge_channel->suspended) {
00723       ast_debug(1, "Going into a multithreaded waitfor for bridge channel %p of bridge %p\n", bridge_channel, bridge_channel->bridge);
00724       chan = ast_waitfor_nandfds(&bridge_channel->chan, 1, fds, nfds, NULL, &outfd, &ms);
00725    } else {
00726       ast_mutex_lock(&bridge_channel->lock);
00727       ast_debug(1, "Going into a multithreaded signal wait for bridge channel %p of bridge %p\n", bridge_channel, bridge_channel->bridge);
00728       ast_cond_wait(&bridge_channel->cond, &bridge_channel->lock);
00729       ast_mutex_unlock(&bridge_channel->lock);
00730    }
00731 
00732    ao2_lock(bridge_channel->bridge);
00733 
00734    if (!bridge_channel->suspended) {
00735       ast_bridge_handle_trip(bridge_channel->bridge, bridge_channel, chan, outfd);
00736    }
00737 
00738    return bridge_channel->state;
00739 }
00740 
00741 /*! \brief Run in a singlethreaded model. Each joined channel yields itself to the main bridge thread. TODO: Improve */
00742 static enum ast_bridge_channel_state bridge_channel_join_singlethreaded(struct ast_bridge_channel *bridge_channel)
00743 {
00744    ao2_unlock(bridge_channel->bridge);
00745    ast_mutex_lock(&bridge_channel->lock);
00746    if (bridge_channel->state == AST_BRIDGE_CHANNEL_STATE_WAIT) {
00747       ast_debug(1, "Going into a single threaded signal wait for bridge channel %p of bridge %p\n", bridge_channel, bridge_channel->bridge);
00748       ast_cond_wait(&bridge_channel->cond, &bridge_channel->lock);
00749    }
00750    ast_mutex_unlock(&bridge_channel->lock);
00751    ao2_lock(bridge_channel->bridge);
00752 
00753    return bridge_channel->state;
00754 }
00755 
00756 /*! \brief Internal function that suspends a channel from a bridge */
00757 static void bridge_channel_suspend(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
00758 {
00759    bridge_channel->suspended = 1;
00760 
00761    bridge_array_remove(bridge, bridge_channel->chan);
00762 
00763    if (bridge->technology->suspend) {
00764       bridge->technology->suspend(bridge, bridge_channel);
00765    }
00766 
00767    return;
00768 }
00769 
00770 /*! \brief Internal function that unsuspends a channel from a bridge */
00771 static void bridge_channel_unsuspend(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
00772 {
00773    bridge_channel->suspended =0;
00774 
00775    bridge_array_add(bridge, bridge_channel->chan);
00776 
00777    if (bridge->technology->unsuspend) {
00778       bridge->technology->unsuspend(bridge, bridge_channel);
00779    }
00780 
00781    return;
00782 }
00783 
00784 /*! \brief Internal function that executes a feature on a bridge channel */
00785 static void bridge_channel_feature(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
00786 {
00787    struct ast_bridge_features *features = (bridge_channel->features ? bridge_channel->features : &bridge->features);
00788    struct ast_bridge_features_hook *hook = NULL;
00789    char dtmf[MAXIMUM_DTMF_FEATURE_STRING] = "";
00790    int look_for_dtmf = 1, dtmf_len = 0;
00791 
00792    /* The channel is now under our control and we don't really want any begin frames to do our DTMF matching so disable 'em at the core level */
00793    ast_set_flag(bridge_channel->chan, AST_FLAG_END_DTMF_ONLY);
00794 
00795    /* Wait for DTMF on the channel and put it into a buffer. If the buffer matches any feature hook execute the hook. */
00796    while (look_for_dtmf) {
00797       int res = ast_waitfordigit(bridge_channel->chan, 3000);
00798 
00799       /* If the above timed out simply exit */
00800       if (!res) {
00801          ast_debug(1, "DTMF feature string collection on bridge channel %p timed out\n", bridge_channel);
00802          break;
00803       } else if (res < 0) {
00804          ast_debug(1, "DTMF feature string collection failed on bridge channel %p for some reason\n", bridge_channel);
00805          break;
00806       }
00807 
00808       /* Add the above DTMF into the DTMF string so we can do our matching */
00809       dtmf[dtmf_len++] = res;
00810 
00811       ast_debug(1, "DTMF feature string on bridge channel %p is now '%s'\n", bridge_channel, dtmf);
00812 
00813       /* Assume that we do not want to look for DTMF any longer */
00814       look_for_dtmf = 0;
00815 
00816       /* See if a DTMF feature hook matches or can match */
00817       AST_LIST_TRAVERSE(&features->hooks, hook, entry) {
00818          /* If this hook matches just break out now */
00819          if (!strcmp(hook->dtmf, dtmf)) {
00820             ast_debug(1, "DTMF feature hook %p matched DTMF string '%s' on bridge channel %p\n", hook, dtmf, bridge_channel);
00821             break;
00822          } else if (!strncmp(hook->dtmf, dtmf, dtmf_len)) {
00823             ast_debug(1, "DTMF feature hook %p can match DTMF string '%s', it wants '%s', on bridge channel %p\n", hook, dtmf, hook->dtmf, bridge_channel);
00824             look_for_dtmf = 1;
00825          } else {
00826             ast_debug(1, "DTMF feature hook %p does not match DTMF string '%s', it wants '%s', on bridge channel %p\n", hook, dtmf, hook->dtmf, bridge_channel);
00827          }
00828       }
00829 
00830       /* If we have reached the maximum length of a DTMF feature string bail out */
00831       if (dtmf_len == MAXIMUM_DTMF_FEATURE_STRING) {
00832          break;
00833       }
00834    }
00835 
00836    /* Since we are done bringing DTMF in return to using both begin and end frames */
00837    ast_clear_flag(bridge_channel->chan, AST_FLAG_END_DTMF_ONLY);
00838 
00839    /* If a hook was actually matched execute it on this channel, otherwise stream up the DTMF to the other channels */
00840    if (hook) {
00841       hook->callback(bridge, bridge_channel, hook->hook_pvt);
00842    } else {
00843       ast_bridge_dtmf_stream(bridge, dtmf, bridge_channel->chan);
00844       ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_WAIT);
00845    }
00846 
00847    return;
00848 }
00849 
00850 /*! \brief Internal function that plays back DTMF on a bridge channel */
00851 static void bridge_channel_dtmf_stream(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
00852 {
00853    char dtmf_q[8] = "";
00854 
00855    ast_copy_string(dtmf_q, bridge_channel->dtmf_stream_q, sizeof(dtmf_q));
00856    bridge_channel->dtmf_stream_q[0] = '\0';
00857 
00858    ast_debug(1, "Playing DTMF stream '%s' out to bridge channel %p\n", dtmf_q, bridge_channel);
00859    ast_dtmf_stream(bridge_channel->chan, NULL, dtmf_q, 250, 0);
00860 
00861    ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_WAIT);
00862 
00863    return;
00864 }
00865 
00866 /*! \brief Join a channel to a bridge and handle anything the bridge may want us to do */
00867 static enum ast_bridge_channel_state bridge_channel_join(struct ast_bridge_channel *bridge_channel)
00868 {
00869    int formats[2] = { bridge_channel->chan->readformat, bridge_channel->chan->writeformat };
00870    enum ast_bridge_channel_state state;
00871 
00872    /* Record the thread that will be the owner of us */
00873    bridge_channel->thread = pthread_self();
00874 
00875    ast_debug(1, "Joining bridge channel %p to bridge %p\n", bridge_channel, bridge_channel->bridge);
00876 
00877    ao2_lock(bridge_channel->bridge);
00878 
00879    state = bridge_channel->state;
00880 
00881    /* Add channel into the bridge */
00882    AST_LIST_INSERT_TAIL(&bridge_channel->bridge->channels, bridge_channel, entry);
00883    bridge_channel->bridge->num++;
00884 
00885    bridge_array_add(bridge_channel->bridge, bridge_channel->chan);
00886 
00887    if (bridge_channel->swap) {
00888       struct ast_bridge_channel *bridge_channel2 = NULL;
00889 
00890       /* If we are performing a swap operation we do not need to execute the smart bridge operation as the actual number of channels involved will not have changed, we just need to tell the other channel to leave */
00891       if ((bridge_channel2 = find_bridge_channel(bridge_channel->bridge, bridge_channel->swap))) {
00892          ast_debug(1, "Swapping bridge channel %p out from bridge %p so bridge channel %p can slip in\n", bridge_channel2, bridge_channel->bridge, bridge_channel);
00893          ast_bridge_change_state(bridge_channel2, AST_BRIDGE_CHANNEL_STATE_HANGUP);
00894       }
00895 
00896       bridge_channel->swap = NULL;
00897    } else if (ast_test_flag(&bridge_channel->bridge->feature_flags, AST_BRIDGE_FLAG_SMART)) {
00898       /* Perform the smart bridge operation, basically see if we need to move around between technologies */
00899       smart_bridge_operation(bridge_channel->bridge, bridge_channel, bridge_channel->bridge->num);
00900    }
00901 
00902    /* Make the channel compatible with the bridge */
00903    bridge_make_compatible(bridge_channel->bridge, bridge_channel);
00904 
00905    /* Tell the bridge technology we are joining so they set us up */
00906    if (bridge_channel->bridge->technology->join) {
00907       ast_debug(1, "Giving bridge technology %s notification that %p is joining bridge %p\n", bridge_channel->bridge->technology->name, bridge_channel, bridge_channel->bridge);
00908       if (bridge_channel->bridge->technology->join(bridge_channel->bridge, bridge_channel)) {
00909          ast_debug(1, "Bridge technology %s failed to join %p to bridge %p\n", bridge_channel->bridge->technology->name, bridge_channel, bridge_channel->bridge);
00910       }
00911    }
00912 
00913    /* Actually execute the respective threading model, and keep our bridge thread alive */
00914    while (bridge_channel->state == AST_BRIDGE_CHANNEL_STATE_WAIT) {
00915       /* Update bridge pointer on channel */
00916       bridge_channel->chan->bridge = bridge_channel->bridge;
00917       /* If the technology requires a thread and one is not running, start it up */
00918       if (bridge_channel->bridge->thread == AST_PTHREADT_NULL && (bridge_channel->bridge->technology->capabilities & AST_BRIDGE_CAPABILITY_THREAD)) {
00919          bridge_channel->bridge->stop = 0;
00920          ast_debug(1, "Starting a bridge thread for bridge %p\n", bridge_channel->bridge);
00921          ao2_ref(bridge_channel->bridge, +1);
00922          if (ast_pthread_create(&bridge_channel->bridge->thread, NULL, bridge_thread, bridge_channel->bridge)) {
00923             ast_debug(1, "Failed to create a bridge thread for bridge %p, giving it another go.\n", bridge_channel->bridge);
00924             ao2_ref(bridge_channel->bridge, -1);
00925             continue;
00926          }
00927       }
00928       /* Execute the threading model */
00929       state = (bridge_channel->bridge->technology->capabilities & AST_BRIDGE_CAPABILITY_MULTITHREADED ? bridge_channel_join_multithreaded(bridge_channel) : bridge_channel_join_singlethreaded(bridge_channel));
00930       /* Depending on the above state see what we need to do */
00931       if (state == AST_BRIDGE_CHANNEL_STATE_FEATURE) {
00932          bridge_channel_suspend(bridge_channel->bridge, bridge_channel);
00933          bridge_channel_feature(bridge_channel->bridge, bridge_channel);
00934          bridge_channel_unsuspend(bridge_channel->bridge, bridge_channel);
00935       } else if (state == AST_BRIDGE_CHANNEL_STATE_DTMF) {
00936          bridge_channel_suspend(bridge_channel->bridge, bridge_channel);
00937          bridge_channel_dtmf_stream(bridge_channel->bridge, bridge_channel);
00938          bridge_channel_unsuspend(bridge_channel->bridge, bridge_channel);
00939       }
00940    }
00941 
00942    bridge_channel->chan->bridge = NULL;
00943 
00944    /* See if we need to dissolve the bridge itself if they hung up */
00945    if (bridge_channel->state == AST_BRIDGE_CHANNEL_STATE_END) {
00946       bridge_check_dissolve(bridge_channel->bridge, bridge_channel);
00947    }
00948 
00949    /* Tell the bridge technology we are leaving so they tear us down */
00950    if (bridge_channel->bridge->technology->leave) {
00951       ast_debug(1, "Giving bridge technology %s notification that %p is leaving bridge %p\n", bridge_channel->bridge->technology->name, bridge_channel, bridge_channel->bridge);
00952       if (bridge_channel->bridge->technology->leave(bridge_channel->bridge, bridge_channel)) {
00953          ast_debug(1, "Bridge technology %s failed to leave %p from bridge %p\n", bridge_channel->bridge->technology->name, bridge_channel, bridge_channel->bridge);
00954       }
00955    }
00956 
00957    /* Remove channel from the bridge */
00958    bridge_channel->bridge->num--;
00959    AST_LIST_REMOVE(&bridge_channel->bridge->channels, bridge_channel, entry);
00960 
00961    bridge_array_remove(bridge_channel->bridge, bridge_channel->chan);
00962 
00963    /* Perform the smart bridge operation if needed since a channel has left */
00964    if (ast_test_flag(&bridge_channel->bridge->feature_flags, AST_BRIDGE_FLAG_SMART)) {
00965       smart_bridge_operation(bridge_channel->bridge, NULL, bridge_channel->bridge->num);
00966    }
00967 
00968    ao2_unlock(bridge_channel->bridge);
00969 
00970    /* Restore original formats of the channel as they came in */
00971    if (bridge_channel->chan->readformat != formats[0]) {
00972       ast_debug(1, "Bridge is returning %p to read format %s(%d)\n", bridge_channel, ast_getformatname(formats[0]), formats[0]);
00973       if (ast_set_read_format(bridge_channel->chan, formats[0])) {
00974          ast_debug(1, "Bridge failed to return channel %p to read format %s(%d)\n", bridge_channel, ast_getformatname(formats[0]), formats[0]);
00975       }
00976    }
00977    if (bridge_channel->chan->writeformat != formats[1]) {
00978       ast_debug(1, "Bridge is returning %p to write format %s(%d)\n", bridge_channel, ast_getformatname(formats[1]), formats[1]);
00979       if (ast_set_write_format(bridge_channel->chan, formats[1])) {
00980          ast_debug(1, "Bridge failed to return channel %p to write format %s(%d)\n", bridge_channel, ast_getformatname(formats[1]), formats[1]);
00981       }
00982    }
00983 
00984    return bridge_channel->state;
00985 }
00986 
00987 enum ast_bridge_channel_state ast_bridge_join(struct ast_bridge *bridge, struct ast_channel *chan, struct ast_channel *swap, struct ast_bridge_features *features)
00988 {
00989    struct ast_bridge_channel bridge_channel = {
00990       .chan = chan,
00991       .swap = swap,
00992       .bridge = bridge,
00993       .features = features,
00994    };
00995    enum ast_bridge_channel_state state;
00996 
00997    /* Initialize various other elements of the bridge channel structure that we can't do above */
00998    ast_mutex_init(&bridge_channel.lock);
00999    ast_cond_init(&bridge_channel.cond, NULL);
01000 
01001    ao2_ref(bridge_channel.bridge, +1);
01002 
01003    state = bridge_channel_join(&bridge_channel);
01004 
01005    ao2_ref(bridge_channel.bridge, -1);
01006 
01007    /* Destroy some elements of the bridge channel structure above */
01008    ast_mutex_destroy(&bridge_channel.lock);
01009    ast_cond_destroy(&bridge_channel.cond);
01010 
01011    return state;
01012 }
01013 
01014 /*! \brief Thread responsible for imparted bridged channels */
01015 static void *bridge_channel_thread(void *data)
01016 {
01017    struct ast_bridge_channel *bridge_channel = data;
01018    enum ast_bridge_channel_state state;
01019 
01020    state = bridge_channel_join(bridge_channel);
01021 
01022    ao2_ref(bridge_channel->bridge, -1);
01023 
01024    /* If no other thread is going to take the channel then hang it up, or else we would have to service it until something else came along */
01025    if (state == AST_BRIDGE_CHANNEL_STATE_END || state == AST_BRIDGE_CHANNEL_STATE_HANGUP) {
01026       ast_hangup(bridge_channel->chan);
01027    }
01028 
01029    /* Destroy elements of the bridge channel structure and the bridge channel structure itself */
01030    ast_mutex_destroy(&bridge_channel->lock);
01031    ast_cond_destroy(&bridge_channel->cond);
01032    ast_free(bridge_channel);
01033 
01034    return NULL;
01035 }
01036 
01037 int ast_bridge_impart(struct ast_bridge *bridge, struct ast_channel *chan, struct ast_channel *swap, struct ast_bridge_features *features)
01038 {
01039    struct ast_bridge_channel *bridge_channel = NULL;
01040 
01041    /* Try to allocate a structure for the bridge channel */
01042    if (!(bridge_channel = ast_calloc(1, sizeof(*bridge_channel)))) {
01043       return -1;
01044    }
01045 
01046    /* Setup various parameters */
01047    bridge_channel->chan = chan;
01048    bridge_channel->swap = swap;
01049    bridge_channel->bridge = bridge;
01050    bridge_channel->features = features;
01051 
01052    /* Initialize our mutex lock and condition */
01053    ast_mutex_init(&bridge_channel->lock);
01054    ast_cond_init(&bridge_channel->cond, NULL);
01055 
01056    /* Bump up the reference count on the bridge, it'll get decremented later */
01057    ao2_ref(bridge, +1);
01058 
01059    /* Actually create the thread that will handle the channel */
01060    if (ast_pthread_create(&bridge_channel->thread, NULL, bridge_channel_thread, bridge_channel)) {
01061       ao2_ref(bridge, -1);
01062       ast_cond_destroy(&bridge_channel->cond);
01063       ast_mutex_destroy(&bridge_channel->lock);
01064       ast_free(bridge_channel);
01065       return -1;
01066    }
01067 
01068    return 0;
01069 }
01070 
01071 int ast_bridge_depart(struct ast_bridge *bridge, struct ast_channel *chan)
01072 {
01073    struct ast_bridge_channel *bridge_channel = NULL;
01074    pthread_t thread;
01075 
01076    ao2_lock(bridge);
01077 
01078    /* Try to find the channel that we want to depart */
01079    if (!(bridge_channel = find_bridge_channel(bridge, chan))) {
01080       ao2_unlock(bridge);
01081       return -1;
01082    }
01083 
01084    ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_DEPART);
01085    thread = bridge_channel->thread;
01086 
01087    ao2_unlock(bridge);
01088 
01089    pthread_join(thread, NULL);
01090 
01091    return 0;
01092 }
01093 
01094 int ast_bridge_remove(struct ast_bridge *bridge, struct ast_channel *chan)
01095 {
01096    struct ast_bridge_channel *bridge_channel = NULL;
01097 
01098    ao2_lock(bridge);
01099 
01100    /* Try to find the channel that we want to remove */
01101    if (!(bridge_channel = find_bridge_channel(bridge, chan))) {
01102       ao2_unlock(bridge);
01103       return -1;
01104    }
01105 
01106    ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_HANGUP);
01107 
01108    ao2_unlock(bridge);
01109 
01110    return 0;
01111 }
01112 
01113 int ast_bridge_merge(struct ast_bridge *bridge0, struct ast_bridge *bridge1)
01114 {
01115    struct ast_bridge_channel *bridge_channel = NULL;
01116 
01117    ao2_lock(bridge0);
01118    ao2_lock(bridge1);
01119 
01120    /* If the first bridge currently has 2 channels and is not capable of becoming a multimixing bridge we can not merge */
01121    if ((bridge0->num + bridge1->num) > 2 && (!(bridge0->technology->capabilities & AST_BRIDGE_CAPABILITY_MULTIMIX) && !ast_test_flag(&bridge0->feature_flags, AST_BRIDGE_FLAG_SMART))) {
01122       ao2_unlock(bridge1);
01123       ao2_unlock(bridge0);
01124       ast_debug(1, "Can't merge bridge %p into bridge %p, multimix is needed and it could not be acquired.\n", bridge1, bridge0);
01125       return -1;
01126    }
01127 
01128    ast_debug(1, "Merging channels from bridge %p into bridge %p\n", bridge1, bridge0);
01129 
01130    /* Perform smart bridge operation on bridge we are merging into so it can change bridge technology if needed */
01131    if (smart_bridge_operation(bridge0, NULL, bridge0->num + bridge1->num)) {
01132       ao2_unlock(bridge1);
01133       ao2_unlock(bridge0);
01134       ast_debug(1, "Can't merge bridge %p into bridge %p, tried to perform smart bridge operation and failed.\n", bridge1, bridge0);
01135       return -1;
01136    }
01137 
01138    /* If a thread is currently executing on bridge1 tell it to stop */
01139    if (bridge1->thread) {
01140       ast_debug(1, "Telling bridge thread on bridge %p to stop as it is being merged into %p\n", bridge1, bridge0);
01141       bridge1->thread = AST_PTHREADT_STOP;
01142    }
01143 
01144    /* Move channels from bridge1 over to bridge0 */
01145    while ((bridge_channel = AST_LIST_REMOVE_HEAD(&bridge1->channels, entry))) {
01146       /* Tell the technology handling bridge1 that the bridge channel is leaving */
01147       if (bridge1->technology->leave) {
01148          ast_debug(1, "Giving bridge technology %s notification that %p is leaving bridge %p\n", bridge1->technology->name, bridge_channel, bridge1);
01149          if (bridge1->technology->leave(bridge1, bridge_channel)) {
01150             ast_debug(1, "Bridge technology %s failed to allow %p to leave bridge %p\n", bridge1->technology->name, bridge_channel, bridge1);
01151          }
01152       }
01153 
01154       /* Drop channel count and reference count on the bridge they are leaving */
01155       bridge1->num--;
01156       ao2_ref(bridge1, -1);
01157 
01158       bridge_array_remove(bridge1, bridge_channel->chan);
01159 
01160       /* Now add them into the bridge they are joining, increase channel count, and bump up reference count */
01161       bridge_channel->bridge = bridge0;
01162       AST_LIST_INSERT_TAIL(&bridge0->channels, bridge_channel, entry);
01163       bridge0->num++;
01164       ao2_ref(bridge0, +1);
01165 
01166       bridge_array_add(bridge0, bridge_channel->chan);
01167 
01168       /* Make the channel compatible with the new bridge it is joining or else formats would go amuck */
01169       bridge_make_compatible(bridge0, bridge_channel);
01170 
01171       /* Tell the technology handling bridge0 that the bridge channel is joining */
01172       if (bridge0->technology->join) {
01173          ast_debug(1, "Giving bridge technology %s notification that %p is joining bridge %p\n", bridge0->technology->name, bridge_channel, bridge0);
01174          if (bridge0->technology->join(bridge0, bridge_channel)) {
01175             ast_debug(1, "Bridge technology %s failed to join %p to bridge %p\n", bridge0->technology->name, bridge_channel, bridge0);
01176          }
01177       }
01178 
01179       /* Poke the bridge channel, this will cause it to wake up and execute the proper threading model for the new bridge it is in */
01180       pthread_kill(bridge_channel->thread, SIGURG);
01181       ast_mutex_lock(&bridge_channel->lock);
01182       ast_cond_signal(&bridge_channel->cond);
01183       ast_mutex_unlock(&bridge_channel->lock);
01184    }
01185 
01186    ast_debug(1, "Merged channels from bridge %p into bridge %p\n", bridge1, bridge0);
01187 
01188    ao2_unlock(bridge1);
01189    ao2_unlock(bridge0);
01190 
01191    return 0;
01192 }
01193 
01194 int ast_bridge_suspend(struct ast_bridge *bridge, struct ast_channel *chan)
01195 {
01196    struct ast_bridge_channel *bridge_channel;
01197 
01198    ao2_lock(bridge);
01199 
01200    if (!(bridge_channel = find_bridge_channel(bridge, chan))) {
01201       ao2_unlock(bridge);
01202       return -1;
01203    }
01204 
01205    bridge_channel_suspend(bridge, bridge_channel);
01206 
01207    ao2_unlock(bridge);
01208 
01209    return 0;
01210 }
01211 
01212 int ast_bridge_unsuspend(struct ast_bridge *bridge, struct ast_channel *chan)
01213 {
01214    struct ast_bridge_channel *bridge_channel;
01215 
01216    ao2_lock(bridge);
01217 
01218    if (!(bridge_channel = find_bridge_channel(bridge, chan))) {
01219       ao2_unlock(bridge);
01220       return -1;
01221    }
01222 
01223    bridge_channel_unsuspend(bridge, bridge_channel);
01224 
01225    ao2_unlock(bridge);
01226 
01227    return 0;
01228 }
01229 
01230 void ast_bridge_technology_suspend(struct ast_bridge_technology *technology)
01231 {
01232    technology->suspended = 1;
01233    return;
01234 }
01235 
01236 void ast_bridge_technology_unsuspend(struct ast_bridge_technology *technology)
01237 {
01238    technology->suspended = 0;
01239    return;
01240 }
01241 
01242 int ast_bridge_features_register(enum ast_bridge_builtin_feature feature, ast_bridge_features_hook_callback callback, const char *dtmf)
01243 {
01244    if (builtin_features_handlers[feature]) {
01245       return -1;
01246    }
01247 
01248    if (!ast_strlen_zero(dtmf)) {
01249       ast_copy_string(builtin_features_dtmf[feature], dtmf, sizeof(builtin_features_dtmf[feature]));
01250    }
01251 
01252    builtin_features_handlers[feature] = callback;
01253 
01254    return 0;
01255 }
01256 
01257 int ast_bridge_features_unregister(enum ast_bridge_builtin_feature feature)
01258 {
01259    if (!builtin_features_handlers[feature]) {
01260       return -1;
01261    }
01262 
01263    builtin_features_handlers[feature] = NULL;
01264 
01265    return 0;
01266 }
01267 
01268 int ast_bridge_features_hook(struct ast_bridge_features *features, const char *dtmf, ast_bridge_features_hook_callback callback, void *hook_pvt)
01269 {
01270    struct ast_bridge_features_hook *hook = NULL;
01271 
01272    /* Allocate new memory and setup it's various variables */
01273    if (!(hook = ast_calloc(1, sizeof(*hook)))) {
01274       return -1;
01275    }
01276 
01277    ast_copy_string(hook->dtmf, dtmf, sizeof(hook->dtmf));
01278    hook->callback = callback;
01279    hook->hook_pvt = hook_pvt;
01280 
01281    /* Once done we add it onto the list. Now it will be picked up when DTMF is used */
01282    AST_LIST_INSERT_TAIL(&features->hooks, hook, entry);
01283 
01284    features->usable = 1;
01285 
01286    return 0;
01287 }
01288 
01289 int ast_bridge_features_enable(struct ast_bridge_features *features, enum ast_bridge_builtin_feature feature, const char *dtmf, void *config)
01290 {
01291    /* If no alternate DTMF stream was provided use the default one */
01292    if (ast_strlen_zero(dtmf)) {
01293       dtmf = builtin_features_dtmf[feature];
01294       /* If no DTMF is still available (ie: it has been disabled) then error out now */
01295       if (ast_strlen_zero(dtmf)) {
01296          ast_debug(1, "Failed to enable built in feature %d on %p, no DTMF string is available for it.\n", feature, features);
01297          return -1;
01298       }
01299    }
01300 
01301    if (!builtin_features_handlers[feature]) {
01302       return -1;
01303    }
01304 
01305    /* The rest is basically pretty easy. We create another hook using the built in feature's callback and DTMF, easy as pie. */
01306    return ast_bridge_features_hook(features, dtmf, builtin_features_handlers[feature], config);
01307 }
01308 
01309 int ast_bridge_features_set_flag(struct ast_bridge_features *features, enum ast_bridge_feature_flags flag)
01310 {
01311    ast_set_flag(&features->feature_flags, flag);
01312    features->usable = 1;
01313    return 0;
01314 }
01315 
01316 int ast_bridge_features_init(struct ast_bridge_features *features)
01317 {
01318    /* Zero out the structure */
01319    memset(features, 0, sizeof(*features));
01320 
01321    /* Initialize the hooks list, just in case */
01322    AST_LIST_HEAD_INIT_NOLOCK(&features->hooks);
01323 
01324    return 0;
01325 }
01326 
01327 int ast_bridge_features_cleanup(struct ast_bridge_features *features)
01328 {
01329    struct ast_bridge_features_hook *hook = NULL;
01330 
01331    /* This is relatively simple, hooks are kept as a list on the features structure so we just pop them off and free them */
01332    while ((hook = AST_LIST_REMOVE_HEAD(&features->hooks, entry))) {
01333       ast_free(hook);
01334    }
01335 
01336    return 0;
01337 }
01338 
01339 int ast_bridge_dtmf_stream(struct ast_bridge *bridge, const char *dtmf, struct ast_channel *chan)
01340 {
01341    struct ast_bridge_channel *bridge_channel = NULL;
01342 
01343    ao2_lock(bridge);
01344 
01345    AST_LIST_TRAVERSE(&bridge->channels, bridge_channel, entry) {
01346       if (bridge_channel->chan == chan) {
01347          continue;
01348       }
01349       ast_copy_string(bridge_channel->dtmf_stream_q, dtmf, sizeof(bridge_channel->dtmf_stream_q));
01350       ast_bridge_change_state(bridge_channel, AST_BRIDGE_CHANNEL_STATE_DTMF);
01351    }
01352 
01353    ao2_unlock(bridge);
01354 
01355    return 0;
01356 }

Generated on Mon Mar 19 11:30:23 2012 for Asterisk - The Open Source Telephony Project by  doxygen 1.4.7