Thu Feb 5 16:25:37 2009

Asterisk developer's documentation


app_dahdiras.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 Execute an ISDN RAS
00022  *
00023  * \author Mark Spencer <markster@digium.com>
00024  * 
00025  * \ingroup applications
00026  */
00027 
00028 /*** MODULEINFO
00029    <depend>dahdi</depend>
00030  ***/
00031 
00032 #include "asterisk.h"
00033 
00034 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 134254 $")
00035 
00036 #include <sys/ioctl.h>
00037 #include <sys/wait.h>
00038 #ifdef __linux__
00039 #include <sys/signal.h>
00040 #else
00041 #include <signal.h>
00042 #endif /* __linux__ */
00043 
00044 #include <stdlib.h>
00045 #include <unistd.h>
00046 #include <string.h>
00047 #include <stdlib.h>
00048 #include <errno.h>
00049 #include <stdio.h>
00050 #include <fcntl.h>
00051 
00052 #include "asterisk/lock.h"
00053 #include "asterisk/file.h"
00054 #include "asterisk/logger.h"
00055 #include "asterisk/channel.h"
00056 #include "asterisk/pbx.h"
00057 #include "asterisk/module.h"
00058 #include "asterisk/options.h"
00059 
00060 #include "asterisk/dahdi_compat.h"
00061 
00062 static char *dahdi_app = "DAHDIRAS";
00063 static char *zap_app = "ZapRAS";
00064 
00065 static char *dahdi_synopsis = "Executes DAHDI ISDN RAS application";
00066 static char *zap_synopsis = "Executes Zaptel ISDN RAS application";
00067 
00068 static char *dahdi_descrip =
00069 "  DAHDIRAS(args): Executes a RAS server using pppd on the given channel.\n"
00070 "The channel must be a clear channel (i.e. PRI source) and a DAHDI\n"
00071 "channel to be able to use this function (no modem emulation is included).\n"
00072 "Your pppd must have the DAHDI plugin available. Arguments should be\n"
00073 "separated by | characters.\n";
00074 
00075 static char *zap_descrip =
00076 "  ZapRAS(args): Executes a RAS server using pppd on the given channel.\n"
00077 "The channel must be a clear channel (i.e. PRI source) and a Zaptel\n"
00078 "channel to be able to use this function (no modem emulation is included).\n"
00079 "Your pppd must have the Zaptel plugin available. Arguments should be\n"
00080 "separated by | characters.\n";
00081 
00082 #define PPP_MAX_ARGS 32
00083 #define PPP_EXEC  "/usr/sbin/pppd"
00084 
00085 static pid_t spawn_ras(struct ast_channel *chan, char *args)
00086 {
00087    pid_t pid;
00088    int x;   
00089    char *c;
00090 
00091    char *argv[PPP_MAX_ARGS];
00092    int argc = 0;
00093    char *stringp=NULL;
00094    sigset_t fullset, oldset;
00095 
00096    sigfillset(&fullset);
00097    pthread_sigmask(SIG_BLOCK, &fullset, &oldset);
00098 
00099    /* Start by forking */
00100    pid = fork();
00101    if (pid) {
00102       pthread_sigmask(SIG_SETMASK, &oldset, NULL);
00103       return pid;
00104    }
00105 
00106    /* Restore original signal handlers */
00107    for (x=0;x<NSIG;x++)
00108       signal(x, SIG_DFL);
00109 
00110    pthread_sigmask(SIG_UNBLOCK, &fullset, NULL);
00111 
00112    /* Execute RAS on File handles */
00113    dup2(chan->fds[0], STDIN_FILENO);
00114 
00115    /* Drop high priority */
00116    if (ast_opt_high_priority)
00117       ast_set_priority(0);
00118 
00119    /* Close other file descriptors */
00120    for (x=STDERR_FILENO + 1;x<1024;x++) 
00121       close(x);
00122 
00123    /* Reset all arguments */
00124    memset(argv, 0, sizeof(argv));
00125 
00126    /* First argument is executable, followed by standard
00127       arguments for DAHDI PPP */
00128    argv[argc++] = PPP_EXEC;
00129    argv[argc++] = "nodetach";
00130 
00131    /* And all the other arguments */
00132    stringp=args;
00133    c = strsep(&stringp, "|");
00134    while(c && strlen(c) && (argc < (PPP_MAX_ARGS - 4))) {
00135       argv[argc++] = c;
00136       c = strsep(&stringp, "|");
00137    }
00138 
00139    argv[argc++] = "plugin";
00140 #ifdef HAVE_ZAPTEL
00141    argv[argc++] = "zaptel.so";
00142 #else
00143    argv[argc++] = "dahdi.so";
00144 #endif
00145    argv[argc++] = "stdin";
00146 
00147    /* Finally launch PPP */
00148    execv(PPP_EXEC, argv);
00149    fprintf(stderr, "Failed to exec PPPD!\n");
00150    exit(1);
00151 }
00152 
00153 static void run_ras(struct ast_channel *chan, char *args)
00154 {
00155    pid_t pid;
00156    int status;
00157    int res;
00158    int signalled = 0;
00159    struct dahdi_bufferinfo savebi;
00160    int x;
00161    
00162    res = ioctl(chan->fds[0], DAHDI_GET_BUFINFO, &savebi);
00163    if(res) {
00164       ast_log(LOG_WARNING, "Unable to check buffer policy on channel %s\n", chan->name);
00165       return;
00166    }
00167 
00168    pid = spawn_ras(chan, args);
00169    if (pid < 0) {
00170       ast_log(LOG_WARNING, "Failed to spawn RAS\n");
00171    } else {
00172       for (;;) {
00173          res = wait4(pid, &status, WNOHANG, NULL);
00174          if (!res) {
00175             /* Check for hangup */
00176             if (chan->_softhangup && !signalled) {
00177                ast_log(LOG_DEBUG, "Channel '%s' hungup.  Signalling RAS at %d to die...\n", chan->name, pid);
00178                kill(pid, SIGTERM);
00179                signalled=1;
00180             }
00181             /* Try again */
00182             sleep(1);
00183             continue;
00184          }
00185          if (res < 0) {
00186             ast_log(LOG_WARNING, "wait4 returned %d: %s\n", res, strerror(errno));
00187          }
00188          if (option_verbose > 2) {
00189             if (WIFEXITED(status)) {
00190                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated with status %d\n", chan->name, WEXITSTATUS(status));
00191             } else if (WIFSIGNALED(status)) {
00192                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated with signal %d\n", 
00193                    chan->name, WTERMSIG(status));
00194             } else {
00195                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated weirdly.\n", chan->name);
00196             }
00197          }
00198          /* Throw back into audio mode */
00199          x = 1;
00200          ioctl(chan->fds[0], DAHDI_AUDIOMODE, &x);
00201 
00202          /* Restore saved values */
00203          res = ioctl(chan->fds[0], DAHDI_SET_BUFINFO, &savebi);
00204          if (res < 0) {
00205             ast_log(LOG_WARNING, "Unable to set buffer policy on channel %s\n", chan->name);
00206          }
00207          break;
00208       }
00209    }
00210 }
00211 
00212 static int exec(struct ast_channel *chan, void *data)
00213 {
00214    int res=-1;
00215    char *args;
00216    struct ast_module_user *u;
00217    struct dahdi_params ztp;
00218 
00219    if (!data) 
00220       data = "";
00221 
00222    u = ast_module_user_add(chan);
00223 
00224    args = ast_strdupa(data);
00225    
00226    /* Answer the channel if it's not up */
00227    if (chan->_state != AST_STATE_UP)
00228       ast_answer(chan);
00229    if (strcasecmp(chan->tech->type, dahdi_chan_name)) {
00230       if (option_verbose > 1)
00231          ast_verbose(VERBOSE_PREFIX_2 "Channel %s is not a %s channel\n", chan->name, dahdi_chan_name);
00232       sleep(2);
00233    } else {
00234       memset(&ztp, 0, sizeof(ztp));
00235       if (ioctl(chan->fds[0], DAHDI_GET_PARAMS, &ztp)) {
00236          ast_log(LOG_WARNING, "Unable to get parameters\n");
00237       } else if (ztp.sigtype != DAHDI_SIG_CLEAR) {
00238          if (option_verbose > 1)
00239             ast_verbose(VERBOSE_PREFIX_2 "Channel %s is not a clear channel\n", chan->name);
00240       } else {
00241          /* Everything should be okay.  Run PPP. */
00242          if (option_verbose > 2)
00243             ast_verbose(VERBOSE_PREFIX_3 "Starting RAS on %s\n", chan->name);
00244          /* Execute RAS */
00245          run_ras(chan, args);
00246       }
00247    }
00248    ast_module_user_remove(u);
00249    return res;
00250 }
00251 
00252 static int exec_warn(struct ast_channel *chan, void *data)
00253 {
00254    ast_log(LOG_WARNING, "Use of the command %s is deprecated, please use %s instead.\n", zap_app, dahdi_app);
00255 
00256    return exec(chan, data);
00257 }
00258 
00259 static int unload_module(void) 
00260 {
00261    int res = 0;
00262 
00263    if (*dahdi_chan_mode == CHAN_DAHDI_PLUS_ZAP_MODE) {
00264       res |= ast_unregister_application(dahdi_app);
00265    }
00266 
00267    res |= ast_unregister_application(zap_app);
00268    
00269    ast_module_user_hangup_all();
00270 
00271    return res;
00272 }
00273 
00274 static int load_module(void)
00275 {
00276    int res = 0;
00277 
00278    if (*dahdi_chan_mode == CHAN_DAHDI_PLUS_ZAP_MODE) {
00279       res |= ast_register_application(dahdi_app, exec, dahdi_synopsis, dahdi_descrip);
00280    }
00281 
00282    res |= ast_register_application(zap_app, exec_warn, zap_synopsis, zap_descrip);
00283 
00284    return res;
00285 }
00286 
00287 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "DAHDI RAS Application");
00288 

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