app_dahdiras.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Execute an ISDN RAS
 *
 * \author Mark Spencer <[email protected]>
 *
 * \ingroup applications
 */

/*** MODULEINFO
 <depend>dahdi</depend>
 <support_level>deprecated</support_level>
 ***/

#include "asterisk.h"

#include <sys/ioctl.h>
#include <sys/wait.h>
#include <signal.h>
#include <fcntl.h>

#include <dahdi/user.h>

#include "asterisk/lock.h"
#include "asterisk/file.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/app.h"

/*** DOCUMENTATION
 <application name="DAHDIRAS" language="en_US">
 <synopsis>
 Executes DAHDI ISDN RAS application.
 </synopsis>
 <syntax>
 <parameter name="args" required="true">
 <para>A list of parameters to pass to the pppd daemon,
 separated by <literal>,</literal> characters.</para>
 </parameter>
 </syntax>
 <description>
 <para>Executes a RAS server using pppd on the given channel.
 The channel must be a clear channel (i.e. PRI source) and a DAHDI
 channel to be able to use this function (No modem emulation is included).</para>
 <para>Your pppd must be patched to be DAHDI aware.</para>
 </description>
 </application>

 ***/

static const char app[] = "DAHDIRAS";

#define PPP_MAX_ARGS 32
#define PPP_EXEC "/usr/sbin/pppd"

static pid_t spawn_ras(struct ast_channel *chan, char *args)
{
 pid_t pid;
 char *c;

 char *argv[PPP_MAX_ARGS];
 int argc = 0;
 char *stringp=NULL;

 /* Start by forking */
 pid = ast_safe_fork(1);
 if (pid) {
 return pid;
 }

 /* Execute RAS on File handles */
 dup2(ast_channel_fd(chan, 0), STDIN_FILENO);

 /* Drop high priority */
 if (ast_opt_high_priority)
 ast_set_priority(0);

 /* Close other file descriptors */
 ast_close_fds_above_n(STDERR_FILENO);

 /* Reset all arguments */
 memset(argv, 0, sizeof(argv));

 /* First argument is executable, followed by standard
 arguments for DAHDI PPP */
 argv[argc++] = PPP_EXEC;
 argv[argc++] = "nodetach";

 /* And all the other arguments */
 stringp=args;
 c = strsep(&stringp, ",");
 while(c && strlen(c) && (argc < (PPP_MAX_ARGS - 4))) {
 argv[argc++] = c;
 c = strsep(&stringp, ",");
 }

 if (geteuid() == 0) {
 argv[argc++] = "plugin";
 argv[argc++] = "dahdi.so";
 }
 argv[argc++] = "stdin";

 /* Finally launch PPP */
 execv(PPP_EXEC, argv);
 fprintf(stderr, "Failed to exec PPPD!\n");
 exit(1);
}

static void run_ras(struct ast_channel *chan, char *args)
{
 pid_t pid;
 int status;
 int res;
 int signalled = 0;
 struct dahdi_bufferinfo savebi;
 int x;

 res = ioctl(ast_channel_fd(chan, 0), DAHDI_GET_BUFINFO, &savebi);
 if(res) {
 ast_log(LOG_WARNING, "Unable to check buffer policy on channel %s\n", ast_channel_name(chan));
 return;
 }

 pid = spawn_ras(chan, args);
 if (pid < 0) {
 ast_log(LOG_WARNING, "Failed to spawn RAS\n");
 } else {
 for (;;) {
 res = waitpid(pid, &status, WNOHANG);
 if (!res) {
 /* Check for hangup */
 if (ast_check_hangup(chan) && !signalled) {
 ast_debug(1, "Channel '%s' hungup. Signalling RAS at %d to die...\n", ast_channel_name(chan), pid);
 kill(pid, SIGTERM);
 signalled=1;
 }
 /* Try again */
 sleep(1);
 continue;
 }
 if (res < 0) {
 ast_log(LOG_WARNING, "waitpid returned %d: %s\n", res, strerror(errno));
 }
 if (WIFEXITED(status)) {
 ast_verb(3, "RAS on %s terminated with status %d\n", ast_channel_name(chan), WEXITSTATUS(status));
 } else if (WIFSIGNALED(status)) {
 ast_verb(3, "RAS on %s terminated with signal %d\n",
 ast_channel_name(chan), WTERMSIG(status));
 } else {
 ast_verb(3, "RAS on %s terminated weirdly.\n", ast_channel_name(chan));
 }
 /* Throw back into audio mode */
 x = 1;
 ioctl(ast_channel_fd(chan, 0), DAHDI_AUDIOMODE, &x);

 /* Restore saved values */
 res = ioctl(ast_channel_fd(chan, 0), DAHDI_SET_BUFINFO, &savebi);
 if (res < 0) {
 ast_log(LOG_WARNING, "Unable to set buffer policy on channel %s\n", ast_channel_name(chan));
 }
 break;
 }
 }
 ast_safe_fork_cleanup();
}

static int dahdiras_exec(struct ast_channel *chan, const char *data)
{
 int res=-1;
 char *args;
 struct dahdi_params dahdip;

 if (!data)
 data = "";

 args = ast_strdupa(data);

 /* Answer the channel if it's not up */
 if (ast_channel_state(chan) != AST_STATE_UP)
 ast_answer(chan);
 if (strcasecmp(ast_channel_tech(chan)->type, "DAHDI")) {
 /* If it's not a DAHDI channel, we're done. Wait a couple of
 seconds and then hangup... */
 ast_verb(2, "Channel %s is not a DAHDI channel\n", ast_channel_name(chan));
 sleep(2);
 } else {
 memset(&dahdip, 0, sizeof(dahdip));
 if (ioctl(ast_channel_fd(chan, 0), DAHDI_GET_PARAMS, &dahdip)) {
 ast_log(LOG_WARNING, "Unable to get DAHDI parameters\n");
 } else if (dahdip.sigtype != DAHDI_SIG_CLEAR) {
 ast_verb(2, "Channel %s is not a clear channel\n", ast_channel_name(chan));
 } else {
 /* Everything should be okay. Run PPP. */
 ast_verb(3, "Starting RAS on %s\n", ast_channel_name(chan));
 /* Execute RAS */
 run_ras(chan, args);
 }
 }
 return res;
}

static int unload_module(void)
{
 return ast_unregister_application(app);
}

static int load_module(void)
{
 return ((ast_register_application_xml(app, dahdiras_exec)) ? AST_MODULE_LOAD_DECLINE : AST_MODULE_LOAD_SUCCESS);
}

AST_MODULE_INFO_STANDARD_DEPRECATED(ASTERISK_GPL_KEY, "DAHDI ISDN Remote Access Server");