Asterisk.org: Developer Documentation (28 Oct 2009)

Wed Oct 28 15:47:50 2009

## Asterisk developer's documentation

# chan_features.c

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    00001 /*
    00002  * Asterisk -- An open source telephony toolkit.
    00003  *
    00004  * Copyright (C) 1999 - 2005, Digium, Inc.
    00005  *
    00006  * Mark Spencer <markster@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 feature Proxy Channel
    00022  *
    00023  * \note *** Experimental code ****
    00024  *
    00025  * \ingroup channel_drivers
    00026  */
    00027
    00028 #include <stdio.h>
    00029 #include <string.h>
    00030 #include <unistd.h>
    00031 #include <sys/socket.h>
    00032 #include <errno.h>
    00033 #include <stdlib.h>
    00034 #include <fcntl.h>
    00035 #include <netdb.h>
    00036 #include <netinet/in.h>
    00037 #include <arpa/inet.h>
    00038 #include <sys/signal.h>
    00039
    00040 #include "asterisk.h"
    00041
    00042 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 41411 $")
    00043
    00044 #include "asterisk/lock.h"
    00045 #include "asterisk/channel.h"
    00046 #include "asterisk/config.h"
    00047 #include "asterisk/logger.h"
    00048 #include "asterisk/module.h"
    00049 #include "asterisk/pbx.h"
    00050 #include "asterisk/options.h"
    00051 #include "asterisk/lock.h"
    00052 #include "asterisk/sched.h"
    00053 #include "asterisk/io.h"
    00054 #include "asterisk/rtp.h"
    00055 #include "asterisk/acl.h"
    00056 #include "asterisk/callerid.h"
    00057 #include "asterisk/file.h"
    00058 #include "asterisk/cli.h"
    00059 #include "asterisk/app.h"
    00060 #include "asterisk/musiconhold.h"
    00061 #include "asterisk/manager.h"
    00062
    00063 static const char desc[] = "Feature Proxy Channel";
    00064 static const char type[] = "Feature";
    00065 static const char tdesc[] = "Feature Proxy Channel Driver";
    00066
    00067 static int usecnt =0;
    00068 AST_MUTEX_DEFINE_STATIC(usecnt_lock);
    00069
    00070 #define IS_OUTBOUND(a,b) (a == b->chan ? 1 : 0)
    00071
    00072 /* Protect the interface list (of feature_pvt's) */
    00073 AST_MUTEX_DEFINE_STATIC(featurelock);
    00074
    00075 struct feature_sub {
    00076    struct ast_channel *owner;
    00077    int inthreeway;
    00078    int pfd;
    00079    int timingfdbackup;
    00080    int alertpipebackup[2];
    00081 };
    00082
    00083 static struct feature_pvt {
    00084    ast_mutex_t lock;       /* Channel private lock */
    00085    char tech[AST_MAX_EXTENSION];    /* Technology to abstract */
    00086    char dest[AST_MAX_EXTENSION];    /* Destination to abstract */
    00087    struct ast_channel *subchan;
    00088    struct feature_sub subs[3];      /* Subs */
    00089    struct ast_channel *owner;    /* Current Master Channel */
    00090    struct feature_pvt *next;     /* Next entity */
    00091 } *features = NULL;
    00092
    00093 #define SUB_REAL  0        /* Active call */
    00094 #define SUB_CALLWAIT 1        /* Call-Waiting call on hold */
    00095 #define SUB_THREEWAY 2        /* Three-way call */
    00096
    00097 static struct ast_channel *features_request(const char *type, int format, void *data, int *cause);
    00098 static int features_digit(struct ast_channel *ast, char digit);
    00099 static int features_call(struct ast_channel *ast, char *dest, int timeout);
    00100 static int features_hangup(struct ast_channel *ast);
    00101 static int features_answer(struct ast_channel *ast);
    00102 static struct ast_frame *features_read(struct ast_channel *ast);
    00103 static int features_write(struct ast_channel *ast, struct ast_frame *f);
    00104 static int features_indicate(struct ast_channel *ast, int condition);
    00105 static int features_fixup(struct ast_channel *oldchan, struct ast_channel *newchan);
    00106
    00107 static const struct ast_channel_tech features_tech = {
    00108    .type = type,
    00109    .description = tdesc,
    00110    .capabilities = -1,
    00111    .requester = features_request,
    00112    .send_digit = features_digit,
    00113    .call = features_call,
    00114    .hangup = features_hangup,
    00115    .answer = features_answer,
    00116    .read = features_read,
    00117    .write = features_write,
    00118    .exception = features_read,
    00119    .indicate = features_indicate,
    00120    .fixup = features_fixup,
    00121 };
    00122
    00123 static inline void init_sub(struct feature_sub *sub)
    00124 {
    00125    sub->inthreeway = 0;
    00126    sub->pfd = -1;
    00127    sub->timingfdbackup = -1;
    00128    sub->alertpipebackup[0] = sub->alertpipebackup[1] = -1;
    00129 }
    00130
    00131 static inline int indexof(struct feature_pvt *p, struct ast_channel *owner, int nullok)
    00132 {
    00133    int x;
    00134    if (!owner) {
    00135       ast_log(LOG_WARNING, "indexof called on NULL owner??\n");
    00136       return -1;
    00137    }
    00138    for (x=0; x<3; x++) {
    00139       if (owner == p->subs[x].owner)
    00140          return x;
    00141    }
    00142    return -1;
    00143 }
    00144
    00145 #if 0
    00146 static void wakeup_sub(struct feature_pvt *p, int a)
    00147 {
    00148    struct ast_frame null = { AST_FRAME_NULL, };
    00149    for (;;) {
    00150       if (p->subs[a].owner) {
    00151          if (ast_mutex_trylock(&p->subs[a].owner->lock)) {
    00152             ast_mutex_unlock(&p->lock);
    00153             usleep(1);
    00154             ast_mutex_lock(&p->lock);
    00155          } else {
    00156             ast_queue_frame(p->subs[a].owner, &null);
    00157             ast_mutex_unlock(&p->subs[a].owner->lock);
    00158             break;
    00159          }
    00160       } else
    00161          break;
    00162    }
    00163 }
    00164 #endif
    00165
    00166 static void restore_channel(struct feature_pvt *p, int index)
    00167 {
    00168    /* Restore timing/alertpipe */
    00169    p->subs[index].owner->timingfd = p->subs[index].timingfdbackup;
    00170    p->subs[index].owner->alertpipe[0] = p->subs[index].alertpipebackup[0];
    00171    p->subs[index].owner->alertpipe[1] = p->subs[index].alertpipebackup[1];
    00172    p->subs[index].owner->fds[AST_MAX_FDS-1] = p->subs[index].alertpipebackup[0];
    00173    p->subs[index].owner->fds[AST_MAX_FDS-2] = p->subs[index].timingfdbackup;
    00174 }
    00175
    00176 static void update_features(struct feature_pvt *p, int index)
    00177 {
    00178    int x;
    00179    if (p->subs[index].owner) {
    00180       for (x=0; x<AST_MAX_FDS; x++) {
    00181          if (index)
    00182             p->subs[index].owner->fds[x] = -1;
    00183          else
    00184             p->subs[index].owner->fds[x] = p->subchan->fds[x];
    00185       }
    00186       if (!index) {
    00187          /* Copy timings from master channel */
    00188          p->subs[index].owner->timingfd = p->subchan->timingfd;
    00189          p->subs[index].owner->alertpipe[0] = p->subchan->alertpipe[0];
    00190          p->subs[index].owner->alertpipe[1] = p->subchan->alertpipe[1];
    00191          if (p->subs[index].owner->nativeformats != p->subchan->readformat) {
    00192             p->subs[index].owner->nativeformats = p->subchan->readformat;
    00193             if (p->subs[index].owner->readformat)
    00194                ast_set_read_format(p->subs[index].owner, p->subs[index].owner->readformat);
    00195             if (p->subs[index].owner->writeformat)
    00196                ast_set_write_format(p->subs[index].owner, p->subs[index].owner->writeformat);
    00197          }
    00198       } else{
    00199          restore_channel(p, index);
    00200       }
    00201    }
    00202 }
    00203
    00204 #if 0
    00205 static void swap_subs(struct feature_pvt *p, int a, int b)
    00206 {
    00207    int tinthreeway;
    00208    struct ast_channel *towner;
    00209
    00210    ast_log(LOG_DEBUG, "Swapping %d and %d\n", a, b);
    00211
    00212    towner = p->subs[a].owner;
    00213    tinthreeway = p->subs[a].inthreeway;
    00214
    00215    p->subs[a].owner = p->subs[b].owner;
    00216    p->subs[a].inthreeway = p->subs[b].inthreeway;
    00217
    00218    p->subs[b].owner = towner;
    00219    p->subs[b].inthreeway = tinthreeway;
    00220    update_features(p,a);
    00221    update_features(p,b);
    00222    wakeup_sub(p, a);
    00223    wakeup_sub(p, b);
    00224 }
    00225 #endif
    00226
    00227 static int features_answer(struct ast_channel *ast)
    00228 {
    00229    struct feature_pvt *p = ast->tech_pvt;
    00230    int res = -1;
    00231    int x;
    00232
    00233    ast_mutex_lock(&p->lock);
    00234    x = indexof(p, ast, 0);
    00235    if (!x && p->subchan)
    00236       res = ast_answer(p->subchan);
    00237    ast_mutex_unlock(&p->lock);
    00238    return res;
    00239 }
    00240
    00241 static struct ast_frame  *features_read(struct ast_channel *ast)
    00242 {
    00243    static struct ast_frame null_frame = { AST_FRAME_NULL, };
    00244    struct feature_pvt *p = ast->tech_pvt;
    00245    struct ast_frame *f;
    00246    int x;
    00247
    00248    f = &null_frame;
    00249    ast_mutex_lock(&p->lock);
    00250    x = indexof(p, ast, 0);
    00251    if (!x && p->subchan) {
    00252       update_features(p, x);
    00253       f = ast_read(p->subchan);
    00254    }
    00255    ast_mutex_unlock(&p->lock);
    00256    return f;
    00257 }
    00258
    00259 static int features_write(struct ast_channel *ast, struct ast_frame *f)
    00260 {
    00261    struct feature_pvt *p = ast->tech_pvt;
    00262    int res = -1;
    00263    int x;
    00264
    00265    ast_mutex_lock(&p->lock);
    00266    x = indexof(p, ast, 0);
    00267    if (!x && p->subchan)
    00268       res = ast_write(p->subchan, f);
    00269    ast_mutex_unlock(&p->lock);
    00270    return res;
    00271 }
    00272
    00273 static int features_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
    00274 {
    00275    struct feature_pvt *p = newchan->tech_pvt;
    00276    int x;
    00277
    00278    ast_mutex_lock(&p->lock);
    00279    if (p->owner == oldchan)
    00280       p->owner = newchan;
    00281    for (x = 0; x < 3; x++) {
    00282       if (p->subs[x].owner == oldchan)
    00283          p->subs[x].owner = newchan;
    00284    }
    00285    ast_mutex_unlock(&p->lock);
    00286    return 0;
    00287 }
    00288
    00289 static int features_indicate(struct ast_channel *ast, int condition)
    00290 {
    00291    struct feature_pvt *p = ast->tech_pvt;
    00292    int res = -1;
    00293    int x;
    00294
    00295    /* Queue up a frame representing the indication as a control frame */
    00296    ast_mutex_lock(&p->lock);
    00297    x = indexof(p, ast, 0);
    00298    if (!x && p->subchan)
    00299       res = ast_indicate(p->subchan, condition);
    00300    ast_mutex_unlock(&p->lock);
    00301    return res;
    00302 }
    00303
    00304 static int features_digit(struct ast_channel *ast, char digit)
    00305 {
    00306    struct feature_pvt *p = ast->tech_pvt;
    00307    int res = -1;
    00308    int x;
    00309
    00310    /* Queue up a frame representing the indication as a control frame */
    00311    ast_mutex_lock(&p->lock);
    00312    x = indexof(p, ast, 0);
    00313    if (!x && p->subchan)
    00314       res = ast_senddigit(p->subchan, digit);
    00315    ast_mutex_unlock(&p->lock);
    00316    return res;
    00317 }
    00318
    00319 static int features_call(struct ast_channel *ast, char *dest, int timeout)
    00320 {
    00321    struct feature_pvt *p = ast->tech_pvt;
    00322    int res = -1;
    00323    int x;
    00324    char *dest2;
    00325
    00326    dest2 = strchr(dest, '/');
    00327    if (dest2) {
    00328       ast_mutex_lock(&p->lock);
    00329       x = indexof(p, ast, 0);
    00330       if (!x && p->subchan) {
    00331          p->subchan->cid.cid_name = p->owner->cid.cid_name ?
    00332             strdup(p->owner->cid.cid_name) : NULL;
    00333          p->subchan->cid.cid_num = p->owner->cid.cid_num ?
    00334             strdup(p->owner->cid.cid_num) : NULL;
    00335          p->subchan->cid.cid_ani = p->owner->cid.cid_ani ?
    00336             strdup(p->owner->cid.cid_ani) : NULL;
    00337          p->subchan->cid.cid_rdnis = p->owner->cid.cid_rdnis ?
    00338             strdup(p->owner->cid.cid_rdnis) : NULL;
    00339
    00340          p->subchan->cid.cid_pres = p->owner->cid.cid_pres;
    00341          strncpy(p->subchan->language, p->owner->language, sizeof(p->subchan->language) - 1);
    00342          strncpy(p->subchan->accountcode, p->owner->accountcode, sizeof(p->subchan->accountcode) - 1);
    00343          p->subchan->cdrflags = p->owner->cdrflags;
    00344          res = ast_call(p->subchan, dest2, timeout);
    00345          update_features(p, x);
    00346       } else
    00347          ast_log(LOG_NOTICE, "Uhm yah, not quite there with the call waiting...\n");
    00348       ast_mutex_unlock(&p->lock);
    00349    }
    00350    return res;
    00351 }
    00352
    00353 static int features_hangup(struct ast_channel *ast)
    00354 {
    00355    struct feature_pvt *p = ast->tech_pvt;
    00356    struct feature_pvt *cur, *prev=NULL;
    00357    int x;
    00358
    00359    ast_mutex_lock(&p->lock);
    00360    x = indexof(p, ast, 0);
    00361    if (x > -1) {
    00362       restore_channel(p, x);
    00363       p->subs[x].owner = NULL;
    00364       /* XXX Re-arrange, unconference, etc XXX */
    00365    }
    00366    ast->tech_pvt = NULL;
    00367
    00368
    00369    if (!p->subs[SUB_REAL].owner && !p->subs[SUB_CALLWAIT].owner && !p->subs[SUB_THREEWAY].owner) {
    00370       ast_mutex_unlock(&p->lock);
    00371       /* Remove from list */
    00372       ast_mutex_lock(&featurelock);
    00373       cur = features;
    00374       while(cur) {
    00375          if (cur == p) {
    00376             if (prev)
    00377                prev->next = cur->next;
    00378             else
    00379                features = cur->next;
    00380             break;
    00381          }
    00382          prev = cur;
    00383          cur = cur->next;
    00384       }
    00385       ast_mutex_unlock(&featurelock);
    00386       ast_mutex_lock(&p->lock);
    00387       /* And destroy */
    00388       if (p->subchan)
    00389          ast_hangup(p->subchan);
    00390       ast_mutex_unlock(&p->lock);
    00391       ast_mutex_destroy(&p->lock);
    00392       free(p);
    00393       return 0;
    00394    }
    00395    ast_mutex_unlock(&p->lock);
    00396    return 0;
    00397 }
    00398
    00399 static struct feature_pvt *features_alloc(char *data, int format)
    00400 {
    00401    struct feature_pvt *tmp;
    00402    char *dest=NULL;
    00403    char *tech;
    00404    int x;
    00405    int status;
    00406    struct ast_channel *chan;
    00407
    00408    tech = ast_strdupa(data);
    00409    if (tech) {
    00410       dest = strchr(tech, '/');
    00411       if (dest) {
    00412          *dest = '\0';
    00413          dest++;
    00414       }
    00415    }
    00416    if (!tech || !dest) {
    00417       ast_log(LOG_NOTICE, "Format for feature channel is Feature/Tech/Dest ('%s' not valid)!\n",
    00418          data);
    00419       return NULL;
    00420    }
    00421    ast_mutex_lock(&featurelock);
    00422    tmp = features;
    00423    while(tmp) {
    00424       if (!strcasecmp(tmp->tech, tech) && !strcmp(tmp->dest, dest))
    00425          break;
    00426       tmp = tmp->next;
    00427    }
    00428    ast_mutex_unlock(&featurelock);
    00429    if (!tmp) {
    00430       chan = ast_request(tech, format, dest, &status);
    00431       if (!chan) {
    00432          ast_log(LOG_NOTICE, "Unable to allocate subchannel '%s/%s'\n", tech, dest);
    00433          return NULL;
    00434       }
    00435       tmp = malloc(sizeof(struct feature_pvt));
    00436       if (tmp) {
    00437          memset(tmp, 0, sizeof(struct feature_pvt));
    00438          for (x=0;x<3;x++)
    00439             init_sub(tmp->subs + x);
    00440          ast_mutex_init(&tmp->lock);
    00441          strncpy(tmp->tech, tech, sizeof(tmp->tech) - 1);
    00442          strncpy(tmp->dest, dest, sizeof(tmp->dest) - 1);
    00443          tmp->subchan = chan;
    00444          ast_mutex_lock(&featurelock);
    00445          tmp->next = features;
    00446          features = tmp;
    00447          ast_mutex_unlock(&featurelock);
    00448       }
    00449    }
    00450    return tmp;
    00451 }
    00452
    00453 static struct ast_channel *features_new(struct feature_pvt *p, int state, int index)
    00454 {
    00455    struct ast_channel *tmp;
    00456    int x,y;
    00457    if (!p->subchan) {
    00458       ast_log(LOG_WARNING, "Called upon channel with no subchan:(\n");
    00459       return NULL;
    00460    }
    00461    if (p->subs[index].owner) {
    00462       ast_log(LOG_WARNING, "Called to put index %d already there!\n", index);
    00463       return NULL;
    00464    }
    00465    tmp = ast_channel_alloc(0);
    00466    if (!tmp) {
    00467       ast_log(LOG_WARNING, "Unable to allocate channel structure\n");
    00468       return NULL;
    00469    }
    00470    tmp->tech = &features_tech;
    00471    for (x=1;x<4;x++) {
    00472       snprintf(tmp->name, sizeof(tmp->name), "Feature/%s/%s-%d", p->tech, p->dest, x);
    00473       for (y=0;y<3;y++) {
    00474          if (y == index)
    00475             continue;
    00476          if (p->subs[y].owner && !strcasecmp(p->subs[y].owner->name, tmp->name))
    00477             break;
    00478       }
    00479       if (y >= 3)
    00480          break;
    00481    }
    00482    tmp->type = type;
    00483    ast_setstate(tmp, state);
    00484    tmp->writeformat = p->subchan->writeformat;
    00485    tmp->rawwriteformat = p->subchan->rawwriteformat;
    00486    tmp->readformat = p->subchan->readformat;
    00487    tmp->rawreadformat = p->subchan->rawreadformat;
    00488    tmp->nativeformats = p->subchan->readformat;
    00489    tmp->tech_pvt = p;
    00490    p->subs[index].owner = tmp;
    00491    if (!p->owner)
    00492       p->owner = tmp;
    00493    ast_mutex_lock(&usecnt_lock);
    00494    usecnt++;
    00495    ast_mutex_unlock(&usecnt_lock);
    00496    ast_update_use_count();
    00497    return tmp;
    00498 }
    00499
    00500
    00501 static struct ast_channel *features_request(const char *type, int format, void *data, int *cause)
    00502 {
    00503    struct feature_pvt *p;
    00504    struct ast_channel *chan = NULL;
    00505
    00506    p = features_alloc(data, format);
    00507    if (p && !p->subs[SUB_REAL].owner)
    00508       chan = features_new(p, AST_STATE_DOWN, SUB_REAL);
    00509    if (chan)
    00510       update_features(p,SUB_REAL);
    00511    return chan;
    00512 }
    00513
    00514 static int features_show(int fd, int argc, char **argv)
    00515 {
    00516    struct feature_pvt *p;
    00517
    00518    if (argc != 3)
    00519       return RESULT_SHOWUSAGE;
    00520    ast_mutex_lock(&featurelock);
    00521    p = features;
    00522    while(p) {
    00523       ast_mutex_lock(&p->lock);
    00524       ast_cli(fd, "%s -- %s/%s\n", p->owner ? p->owner->name : "<unowned>", p->tech, p->dest);
    00525       ast_mutex_unlock(&p->lock);
    00526       p = p->next;
    00527    }
    00528    if (!features)
    00529       ast_cli(fd, "No feature channels in use\n");
    00530    ast_mutex_unlock(&featurelock);
    00531    return RESULT_SUCCESS;
    00532 }
    00533
    00534 static char show_features_usage[] =
    00535 "Usage: feature show channels\n"
    00536 "       Provides summary information on feature channels.\n";
    00537
    00538 static struct ast_cli_entry cli_show_features = {
    00539    { "feature", "show", "channels", NULL }, features_show,
    00540    "Show status of feature channels", show_features_usage, NULL };
    00541
    00542 int load_module()
    00543 {
    00544    /* Make sure we can register our sip channel type */
    00545    if (ast_channel_register(&features_tech)) {
    00546       ast_log(LOG_ERROR, "Unable to register channel class %s\n", type);
    00547       return -1;
    00548    }
    00549    ast_cli_register(&cli_show_features);
    00550    return 0;
    00551 }
    00552
    00553 int reload()
    00554 {
    00555    return 0;
    00556 }
    00557
    00558 int unload_module()
    00559 {
    00560    struct feature_pvt *p, *prev;
    00561    /* First, take us out of the channel loop */
    00562    ast_cli_unregister(&cli_show_features);
    00563    ast_channel_unregister(&features_tech);
    00564    if (!ast_mutex_lock(&featurelock)) {
    00565       /* Hangup all interfaces if they have an owner */
    00566       for (p = features; p; p = p->next) {
    00567          prev = p;
    00568          if (p->owner)
    00569             ast_softhangup(p->owner, AST_SOFTHANGUP_APPUNLOAD);
    00570          free(prev);
    00571       }
    00572       features = NULL;
    00573       ast_mutex_unlock(&featurelock);
    00574    } else {
    00575       ast_log(LOG_WARNING, "Unable to lock the monitor\n");
    00576       return -1;
    00577    }
    00578    return 0;
    00579 }
    00580
    00581 int usecount()
    00582 {
    00583    return usecnt;
    00584 }
    00585
    00586 char *key()
    00587 {
    00588    return ASTERISK_GPL_KEY;
    00589 }
    00590
    00591 char *description()
    00592 {
    00593    return (char *) desc;
    00594 }
    00595