Add app_fax from asterisk-addons, with some additional changes to resolve compiler
authorRussell Bryant <russell@russellbryant.com>
Mon, 2 Jun 2008 16:14:15 +0000 (16:14 +0000)
committerRussell Bryant <russell@russellbryant.com>
Mon, 2 Jun 2008 16:14:15 +0000 (16:14 +0000)
warnings, as well as update to the APIs in spandsp 0.0.5.  Spandsp 0.0.5 is being
distributed under the LGPL, so we can move this module into the main tree.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@119801 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_fax.c [new file with mode: 0644]

diff --git a/apps/app_fax.c b/apps/app_fax.c
new file mode 100644 (file)
index 0000000..cf98cc9
--- /dev/null
@@ -0,0 +1,741 @@
+/*
+ * Asterisk -- A telephony toolkit for Linux.
+ *
+ * Simple fax applications
+ * 
+ * 2007-2008, Dmitry Andrianov <asterisk@dima.spb.ru>
+ *
+ * Code based on original implementation by Steve Underwood <steveu@coppice.org>
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License
+ *
+ */
+
+/*** MODULEINFO
+        <depend>spandsp</depend>
+***/
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include <errno.h>
+#include <tiffio.h>
+
+#include <spandsp.h>
+
+#include "asterisk/lock.h"
+#include "asterisk/file.h"
+#include "asterisk/logger.h"
+#include "asterisk/channel.h"
+#include "asterisk/pbx.h"
+#include "asterisk/app.h"
+#include "asterisk/dsp.h"
+#include "asterisk/module.h"
+#include "asterisk/manager.h"
+
+static char *app_sndfax_name = "SendFAX";
+static char *app_sndfax_synopsis = "Send a FAX";
+static char *app_sndfax_desc = 
+"  SendFAX(filename[|options]):\n"
+"Send a given TIFF file to the channel as a FAX.\n"
+"The option string may contain zero or more of the following characters:\n"
+"     'a' -- makes the application behave as an answering machine\n"
+"          The default behaviour is to behave as a calling machine.\n"
+"\n"
+"This application uses following variables:\n"
+"     LOCALSTATIONID to identify itself to the remote end.\n"
+"     LOCALHEADERINFO to generate a header line on each page.\n"
+"\n"
+"This application sets the following channel variables upon completion:\n"
+"     FAXSTATUS       - status of operation:\n"
+"                         SUCCESS | FAILED\n"
+"     FAXERROR - Error when FAILED\n"
+"     REMOTESTATIONID - CSID of the remote side.\n"
+"     FAXPAGES - number of pages sent.\n"
+"     FAXBITRATE      - transmition rate.\n"
+"     FAXRESOLUTION   - resolution.\n"
+"\n"
+"Returns -1 in case of user hang up or any channel error.\n"
+"Returns 0 on success.\n";
+
+static char *app_rcvfax_name = "ReceiveFAX";
+static char *app_rcvfax_synopsis = "Receive a FAX";
+static char *app_rcvfax_desc = 
+"  ReceiveFAX(filename[|options]):\n"
+"Receives a fax from the channel into the given filename overwriting\n"
+"the file if it already exists. File created will have TIFF format.\n"
+"The option string may contain zero or more of the following characters:\n"
+"     'c' -- makes the application behave as a calling machine\n"
+"          The default behaviour is to behave as an answering machine.\n"
+"\n"
+"This application uses following variables:\n"
+"     LOCALSTATIONID to identify itself to the remote end.\n"
+"     LOCALHEADERINFO to generate a header line on each page.\n"
+"\n"
+"This application sets the following channel variables upon completion:\n"
+"     FAXSTATUS       - status of operation:\n"
+"                         SUCCESS | FAILED\n"
+"     FAXERROR - Error when FAILED\n"
+"     REMOTESTATIONID - CSID of the remote side.\n"
+"     FAXPAGES - number of pages sent.\n"
+"     FAXBITRATE      - transmition rate.\n"
+"     FAXRESOLUTION   - resolution.\n"
+"\n"
+"Returns -1 in case of user hang up or any channel error.\n"
+"Returns 0 on success.\n";
+
+#define MAX_SAMPLES 240
+
+/* Watchdog. I have seen situations when remote fax disconnects (because of poor line
+   quality) while SpanDSP continues staying in T30_STATE_IV_CTC state forever.
+   To avoid this, we terminate when we see that T30 state does not change for 5 minutes.
+   We also terminate application when more than 30 minutes passed regardless of
+   state changes. This is just a precaution measure - no fax should take that long */
+
+#define WATCHDOG_TOTAL_TIMEOUT 30 * 60
+#define WATCHDOG_STATE_TIMEOUT 5 * 60
+
+typedef struct {
+       struct ast_channel *chan;
+       enum ast_t38_state t38state;    /* T38 state of the channel */
+       int direction;                  /* Fax direction: 0 - receiving, 1 - sending */
+       int caller_mode;
+       char *file_name;
+       
+       volatile int finished;
+} fax_session;
+
+static void span_message(int level, const char *msg)
+{
+       if (level == SPAN_LOG_ERROR) {
+               ast_log(LOG_ERROR, "%s", msg);
+       } else if (level == SPAN_LOG_WARNING) {
+               ast_log(LOG_WARNING, "%s", msg);
+       } else {
+               ast_log(LOG_DEBUG, "%s", msg);
+       }
+}
+
+static int t38_tx_packet_handler(t38_core_state_t *s, void *user_data, const uint8_t *buf, int len, int count)
+{
+       struct ast_channel *chan = (struct ast_channel *) user_data;
+
+       struct ast_frame outf = {
+               .frametype = AST_FRAME_MODEM,
+               .subclass = AST_MODEM_T38,
+               .src = __FUNCTION__,
+       };
+
+       /* TODO: Asterisk does not provide means of resending the same packet multiple
+         times so count is ignored at the moment */
+
+       AST_FRAME_SET_BUFFER(&outf, buf, 0, len);
+
+       if (ast_write(chan, &outf) < 0) {
+               ast_log(LOG_WARNING, "Unable to write frame to channel; %s\n", strerror(errno));
+               return -1;
+       }
+
+       return 0;
+}
+
+static void phase_e_handler(t30_state_t *f, void *user_data, int result)
+{
+       const char *local_ident;
+       const char *far_ident;
+       char buf[20];
+       fax_session *s = (fax_session *) user_data;
+       t30_stats_t stat;
+
+       ast_debug(1, "Fax phase E handler. result=%d\n", result);
+
+       t30_get_transfer_statistics(f, &stat);
+
+       s = (fax_session *) user_data;
+
+       if (result != T30_ERR_OK) {
+               s->finished = -1;
+
+               /* FAXSTATUS is already set to FAILED */
+               pbx_builtin_setvar_helper(s->chan, "FAXERROR", t30_completion_code_to_str(result));
+
+               ast_log(LOG_WARNING, "Error transmitting fax. result=%d: %s.\n", result, t30_completion_code_to_str(result));
+
+               return;
+       }
+       
+       s->finished = 1; 
+       
+       local_ident = t30_get_tx_ident(f);
+       far_ident = t30_get_rx_ident(f);
+       pbx_builtin_setvar_helper(s->chan, "FAXSTATUS", "SUCCESS"); 
+       pbx_builtin_setvar_helper(s->chan, "FAXERROR", NULL); 
+       pbx_builtin_setvar_helper(s->chan, "REMOTESTATIONID", far_ident);
+       snprintf(buf, sizeof(buf), "%d", stat.pages_transferred);
+       pbx_builtin_setvar_helper(s->chan, "FAXPAGES", buf);
+       snprintf(buf, sizeof(buf), "%d", stat.y_resolution);
+       pbx_builtin_setvar_helper(s->chan, "FAXRESOLUTION", buf);
+       snprintf(buf, sizeof(buf), "%d", stat.bit_rate);
+       pbx_builtin_setvar_helper(s->chan, "FAXBITRATE", buf); 
+       
+       ast_debug(1, "Fax transmitted successfully.\n");
+       ast_debug(1, "  Remote station ID: %s\n", far_ident);
+       ast_debug(1, "  Pages transferred: %d\n", stat.pages_transferred);
+       ast_debug(1, "  Image resolution:  %d x %d\n", stat.x_resolution, stat.y_resolution);
+       ast_debug(1, "  Transfer Rate:     %d\n", stat.bit_rate);
+       
+       manager_event(EVENT_FLAG_CALL,
+                     s->direction ? "FaxSent" : "FaxReceived", 
+                     "Channel: %s\r\n"
+                     "Exten: %s\r\n"
+                     "CallerID: %s\r\n"
+                     "RemoteStationID: %s\r\n"
+                     "LocalStationID: %s\r\n"
+                     "PagesTransferred: %d\r\n"
+                     "Resolution: %d\r\n"
+                     "TransferRate: %d\r\n"
+                     "FileName: %s\r\n",
+                     s->chan->name,
+                     s->chan->exten,
+                     S_OR(s->chan->cid.cid_num, ""),
+                     far_ident,
+                     local_ident,
+                     stat.pages_transferred,
+                     stat.y_resolution,
+                     stat.bit_rate,
+                     s->file_name);
+}
+
+/* === Helper functions to configure fax === */
+
+/* Setup SPAN logging according to Asterisk debug level */
+static int set_logging(logging_state_t *state)
+{
+       int level = SPAN_LOG_WARNING + option_debug;
+
+       span_log_set_message_handler(state, span_message);
+       span_log_set_level(state, SPAN_LOG_SHOW_SEVERITY | SPAN_LOG_SHOW_PROTOCOL | level); 
+
+       return 0;
+}
+
+static void set_local_info(t30_state_t *state, fax_session *s)
+{
+       const char *x;
+
+       x = pbx_builtin_getvar_helper(s->chan, "LOCALSTATIONID");
+       if (!ast_strlen_zero(x))
+               t30_set_tx_ident(state, x);
+
+       x = pbx_builtin_getvar_helper(s->chan, "LOCALHEADERINFO");
+       if (!ast_strlen_zero(x))
+               t30_set_tx_page_header_info(state, x);
+}
+
+static void set_file(t30_state_t *state, fax_session *s)
+{
+       if (s->direction)
+               t30_set_tx_file(state, s->file_name, -1, -1);
+       else
+               t30_set_rx_file(state, s->file_name, -1);
+}
+
+static void set_ecm(t30_state_t *state, int ecm)
+{
+       t30_set_ecm_capability(state, ecm);
+       t30_set_supported_compressions(state, T30_SUPPORT_T4_1D_COMPRESSION | T30_SUPPORT_T4_2D_COMPRESSION | T30_SUPPORT_T6_COMPRESSION);
+}
+
+/* === Generator === */
+
+/* This function is only needed to return passed params so
+   generator_activate will save it to channel's generatordata */
+static void *fax_generator_alloc(struct ast_channel *chan, void *params)
+{
+       return params;
+}
+
+static int fax_generator_generate(struct ast_channel *chan, void *data, int len, int samples)
+{
+       fax_state_t *fax = (fax_state_t*) data;
+       uint8_t buffer[AST_FRIENDLY_OFFSET + MAX_SAMPLES * sizeof(uint16_t)];
+       int16_t *buf = (int16_t *) (buffer + AST_FRIENDLY_OFFSET);
+    
+       struct ast_frame outf = {
+               .frametype = AST_FRAME_VOICE,
+               .subclass = AST_FORMAT_SLINEAR,
+               .src = __FUNCTION__,
+       };
+
+       if (samples > MAX_SAMPLES) {
+               ast_log(LOG_WARNING, "Only generating %d samples, where %d requested\n", MAX_SAMPLES, samples);
+               samples = MAX_SAMPLES;
+       }
+       
+       if ((len = fax_tx(fax, buf, samples)) > 0) {
+               outf.samples = len;
+               AST_FRAME_SET_BUFFER(&outf, buffer, AST_FRIENDLY_OFFSET, len * sizeof(int16_t));
+
+               if (ast_write(chan, &outf) < 0) {
+                       ast_log(LOG_WARNING, "Failed to write frame to '%s': %s\n", chan->name, strerror(errno));
+                       return -1;
+               }
+       }
+
+       return 0;
+}
+
+struct ast_generator generator = {
+       alloc:          fax_generator_alloc,
+       generate:       fax_generator_generate,
+};
+
+
+/* === Transmission === */
+
+static int transmit_audio(fax_session *s)
+{
+       int res = -1;
+       int original_read_fmt = AST_FORMAT_SLINEAR;
+       int original_write_fmt = AST_FORMAT_SLINEAR;
+       fax_state_t fax;
+       struct ast_dsp *dsp = NULL;
+       int detect_tone = 0;
+       struct ast_frame *inf = NULL;
+       struct ast_frame *fr;
+       int last_state = 0;
+       struct timeval now, start, state_change;
+       enum ast_control_t38 t38control;
+
+       original_read_fmt = s->chan->readformat;
+       if (original_read_fmt != AST_FORMAT_SLINEAR) {
+               res = ast_set_read_format(s->chan, AST_FORMAT_SLINEAR);
+               if (res < 0) {
+                       ast_log(LOG_WARNING, "Unable to set to linear read mode, giving up\n");
+                       goto done;
+               }
+       }
+
+       original_write_fmt = s->chan->writeformat;
+       if (original_write_fmt != AST_FORMAT_SLINEAR) {
+               res = ast_set_write_format(s->chan, AST_FORMAT_SLINEAR);
+               if (res < 0) {
+                       ast_log(LOG_WARNING, "Unable to set to linear write mode, giving up\n");
+                       goto done;
+               }
+       }
+
+       /* Initialize T30 terminal */
+       fax_init(&fax, s->caller_mode);
+
+       /* Setup logging */
+       set_logging(&fax.logging);
+       set_logging(&fax.t30_state.logging);
+
+       /* Configure terminal */
+       set_local_info(&fax.t30_state, s);
+       set_file(&fax.t30_state, s);
+       set_ecm(&fax.t30_state, TRUE);
+
+       fax_set_transmit_on_idle(&fax, TRUE);
+
+       t30_set_phase_e_handler(&fax.t30_state, phase_e_handler, s);
+
+       if (s->t38state == T38_STATE_UNAVAILABLE) {
+               ast_debug(1, "T38 is unavailable on %s\n", s->chan->name);
+       } else if (!s->direction) {
+               /* We are receiving side and this means we are the side which should
+                  request T38 when the fax is detected. Use DSP to detect fax tone */
+               ast_debug(1, "Setting up CNG detection on %s\n", s->chan->name);
+               dsp = ast_dsp_new();
+               ast_dsp_set_features(dsp, DSP_FEATURE_FAX_DETECT);
+               ast_dsp_set_faxmode(dsp, DSP_FAXMODE_DETECT_CNG);
+               detect_tone = 1;
+       }
+
+       start = state_change = ast_tvnow();
+
+       ast_activate_generator(s->chan, &generator, &fax);
+
+       while (!s->finished) {
+               res = ast_waitfor(s->chan, 20);
+               if (res < 0)
+                       break;
+               else if (res > 0)
+                       res = 0;
+
+               inf = ast_read(s->chan);
+               if (inf == NULL) {
+                       ast_debug(1, "Channel hangup\n");
+                       res = -1;
+                       break;
+               }
+
+               ast_debug(10, "frame %d/%d, len=%d\n", inf->frametype, inf->subclass, inf->datalen);
+
+               /* Detect fax tone */
+               if (detect_tone && inf->frametype == AST_FRAME_VOICE) {
+                       /* Duplicate frame because ast_dsp_process may free the frame passed */
+                       fr = ast_frdup(inf);
+
+                       /* Do not pass channel to ast_dsp_process otherwise it may queue modified audio frame back */
+                       fr = ast_dsp_process(NULL, dsp, fr);
+                       if (fr && fr->frametype == AST_FRAME_DTMF && fr->subclass == 'f') {
+                               ast_debug(1, "Fax tone detected. Requesting T38\n");
+                               t38control = AST_T38_REQUEST_NEGOTIATE;
+                               ast_indicate_data(s->chan, AST_CONTROL_T38, &t38control, sizeof(t38control));
+                               detect_tone = 0;
+                       }
+
+                       ast_frfree(fr);
+               }
+
+
+               /* Check the frame type. Format also must be checked because there is a chance
+                  that a frame in old format was already queued before we set chanel format
+                  to slinear so it will still be received by ast_read */
+               if (inf->frametype == AST_FRAME_VOICE && inf->subclass == AST_FORMAT_SLINEAR) {
+
+                       if (fax_rx(&fax, inf->data.ptr, inf->samples) < 0) {
+                               /* I know fax_rx never returns errors. The check here is for good style only */
+                               ast_log(LOG_WARNING, "fax_rx returned error\n");
+                               res = -1;
+                               break;
+                       }
+
+                       /* Watchdog */
+                       if (last_state != fax.t30_state.state) {
+                               state_change = ast_tvnow();
+                               last_state = fax.t30_state.state;
+                       }
+               } else if (inf->frametype == AST_FRAME_CONTROL && inf->subclass == AST_CONTROL_T38 &&
+                               inf->datalen == sizeof(enum ast_control_t38)) {
+                       t38control =*((enum ast_control_t38 *) inf->data.ptr);
+                       if (t38control == AST_T38_NEGOTIATED) {
+                               /* T38 switchover completed */
+                               ast_debug(1, "T38 negotiated, finishing audio loop\n");
+                               res = 1;
+                               break;
+                       }
+               }
+
+               ast_frfree(inf);
+               inf = NULL;
+
+               /* Watchdog */
+               now = ast_tvnow();
+               if (ast_tvdiff_sec(now, start) > WATCHDOG_TOTAL_TIMEOUT || ast_tvdiff_sec(now, state_change) > WATCHDOG_STATE_TIMEOUT) {
+                       ast_log(LOG_WARNING, "It looks like we hung. Aborting.\n");
+                       res = -1;
+                       break;
+               }
+       }
+
+       ast_debug(1, "Loop finished, res=%d\n", res);
+
+       if (inf)
+               ast_frfree(inf);
+
+       if (dsp)
+               ast_dsp_free(dsp);
+
+       ast_deactivate_generator(s->chan);
+
+       /* Remove phase E handler because we do not want it to be executed
+          only because we called t30_terminate */
+       t30_set_phase_e_handler(&fax.t30_state, NULL, NULL);
+
+       t30_terminate(&fax.t30_state);
+       fax_release(&fax);
+
+done:
+       if (original_write_fmt != AST_FORMAT_SLINEAR) {
+               if (ast_set_write_format(s->chan, original_write_fmt) < 0)
+                       ast_log(LOG_WARNING, "Unable to restore write format on '%s'\n", s->chan->name);
+       }
+
+       if (original_read_fmt != AST_FORMAT_SLINEAR) {
+               if (ast_set_read_format(s->chan, original_read_fmt) < 0)
+                       ast_log(LOG_WARNING, "Unable to restore read format on '%s'\n", s->chan->name);
+       }
+
+       return res;
+
+}
+
+static int transmit_t38(fax_session *s)
+{
+       int res = 0;
+       t38_terminal_state_t t38;
+       struct ast_frame *inf = NULL;
+       int last_state = 0;
+       struct timeval now, start, state_change, last_frame;
+       enum ast_control_t38 t38control;
+
+       /* Initialize terminal */
+       memset(&t38, 0, sizeof(t38));
+       if (t38_terminal_init(&t38, s->caller_mode, t38_tx_packet_handler, s->chan) == NULL) {
+               ast_log(LOG_WARNING, "Unable to start T.38 termination.\n");
+               return -1;
+       }
+
+       /* Setup logging */
+       set_logging(&t38.logging);
+       set_logging(&t38.t30_state.logging);
+       set_logging(&t38.t38.logging);
+
+       /* Configure terminal */
+       set_local_info(&t38.t30_state, s);
+       set_file(&t38.t30_state, s);
+       set_ecm(&t38.t30_state, TRUE);
+
+       t30_set_phase_e_handler(&t38.t30_state, phase_e_handler, s);
+
+       now = start = state_change = ast_tvnow();
+
+       while (!s->finished) {
+
+               res = ast_waitfor(s->chan, 20);
+               if (res < 0)
+                       break;
+               else if (res > 0)
+                       res = 0;
+
+               last_frame = now;
+               now = ast_tvnow();
+               t38_terminal_send_timeout(&t38, ast_tvdiff_us(now, last_frame) / (1000000 / 8000));
+
+               inf = ast_read(s->chan);
+               if (inf == NULL) {
+                       ast_debug(1, "Channel hangup\n");
+                       res = -1;
+                       break;
+               }
+
+               ast_debug(10, "frame %d/%d, len=%d\n", inf->frametype, inf->subclass, inf->datalen);
+
+               if (inf->frametype == AST_FRAME_MODEM && inf->subclass == AST_MODEM_T38) {
+                       t38_core_rx_ifp_packet(&t38.t38, inf->data.ptr, inf->datalen, inf->seqno);
+
+                       /* Watchdog */
+                       if (last_state != t38.t30_state.state) {
+                               state_change = ast_tvnow();
+                               last_state = t38.t30_state.state;
+                       }
+               } else if (inf->frametype == AST_FRAME_CONTROL && inf->subclass == AST_CONTROL_T38 &&
+                               inf->datalen == sizeof(enum ast_control_t38)) {
+
+                       t38control = *((enum ast_control_t38 *) inf->data.ptr);
+
+                       if (t38control == AST_T38_TERMINATED || t38control == AST_T38_REFUSED) {
+                               ast_debug(1, "T38 down, terminating\n");
+                               res = -1;
+                               break;
+                       }
+               }
+
+               ast_frfree(inf);
+               inf = NULL;
+
+               /* Watchdog */
+               if (ast_tvdiff_sec(now, start) > WATCHDOG_TOTAL_TIMEOUT || ast_tvdiff_sec(now, state_change) > WATCHDOG_STATE_TIMEOUT) {
+                       ast_log(LOG_WARNING, "It looks like we hung. Aborting.\n");
+                       res = -1;
+                       break;
+               }
+       }
+
+       ast_debug(1, "Loop finished, res=%d\n", res);
+
+       if (inf)
+               ast_frfree(inf);
+
+       /* Remove phase E handler because we do not want it to be executed
+          only because we called t30_terminate */
+       t30_set_phase_e_handler(&t38.t30_state, NULL, NULL);
+
+       t30_terminate(&t38.t30_state);
+
+       return res;
+}
+
+static int transmit(fax_session *s)
+{
+       int res = 0;
+
+       /* Clear all channel variables which to be set by the application.
+          Pre-set status to error so in case of any problems we can just leave */
+       pbx_builtin_setvar_helper(s->chan, "FAXSTATUS", "FAILED"); 
+       pbx_builtin_setvar_helper(s->chan, "FAXERROR", "Channel problems"); 
+
+       pbx_builtin_setvar_helper(s->chan, "REMOTESTATIONID", NULL);
+       pbx_builtin_setvar_helper(s->chan, "FAXPAGES", NULL);
+       pbx_builtin_setvar_helper(s->chan, "FAXRESOLUTION", NULL);
+       pbx_builtin_setvar_helper(s->chan, "FAXBITRATE", NULL); 
+
+       if (s->chan->_state != AST_STATE_UP) {
+               /* Shouldn't need this, but checking to see if channel is already answered
+                * Theoretically asterisk should already have answered before running the app */
+               res = ast_answer(s->chan);
+               if (res) {
+                       ast_log(LOG_WARNING, "Could not answer channel '%s'\n", s->chan->name);
+                       return res;
+               }
+       }
+
+       s->t38state = ast_channel_get_t38_state(s->chan);
+       if (s->t38state != T38_STATE_NEGOTIATED) {
+               /* T38 is not negotiated on the channel yet. First start regular transmission. If it switches to T38, follow */ 
+               res = transmit_audio(s);
+               if (res > 0) {
+                       /* transmit_audio reports switchover to T38. Update t38state */
+                       s->t38state = ast_channel_get_t38_state(s->chan);
+                       if (s->t38state != T38_STATE_NEGOTIATED) {
+                               ast_log(LOG_ERROR, "Audio loop reports T38 switchover but t38state != T38_STATE_NEGOTIATED\n");
+                       }
+               }
+       }
+
+       if (s->t38state == T38_STATE_NEGOTIATED) {
+               res = transmit_t38(s);
+       }
+
+       if (res) {
+               ast_log(LOG_WARNING, "Transmission error\n");
+               res = -1;
+       } else if (s->finished < 0) {
+               ast_log(LOG_WARNING, "Transmission failed\n");
+       } else if (s->finished > 0) {
+               ast_debug(1, "Transmission finished Ok\n");
+       }
+
+       return res;
+}
+
+/* === Application functions === */
+
+static int sndfax_exec(struct ast_channel *chan, void *data)
+{
+       int res = 0;
+       char *parse;
+       fax_session session;
+
+       AST_DECLARE_APP_ARGS(args,
+               AST_APP_ARG(file_name);
+               AST_APP_ARG(options);
+       );
+
+       if (chan == NULL) {
+               ast_log(LOG_ERROR, "Fax channel is NULL. Giving up.\n");
+               return -1;
+       }
+
+       /* The next few lines of code parse out the filename and header from the input string */
+       if (ast_strlen_zero(data)) {
+               /* No data implies no filename or anything is present */
+               ast_log(LOG_ERROR, "SendFAX requires an argument (filename)\n");
+               return -1;
+       }
+
+       parse = ast_strdupa(data);
+       AST_STANDARD_APP_ARGS(args, parse);
+       
+       session.caller_mode = TRUE;
+
+       if (args.options) {
+               if (strchr(args.options, 'a'))
+                       session.caller_mode = FALSE;
+       }
+
+       /* Done parsing */
+       session.direction = 1;
+       session.file_name = args.file_name;
+       session.chan = chan;
+       session.finished = 0;
+
+       res = transmit(&session);
+
+       return res;
+}
+
+static int rcvfax_exec(struct ast_channel *chan, void *data)
+{
+       int res = 0;
+       char *parse;
+       fax_session session;
+
+       AST_DECLARE_APP_ARGS(args,
+               AST_APP_ARG(file_name);
+               AST_APP_ARG(options);
+       );
+
+       if (chan == NULL) {
+               ast_log(LOG_ERROR, "Fax channel is NULL. Giving up.\n");
+               return -1;
+       }
+
+       /* The next few lines of code parse out the filename and header from the input string */
+       if (ast_strlen_zero(data)) {
+               /* No data implies no filename or anything is present */
+               ast_log(LOG_ERROR, "ReceiveFAX requires an argument (filename)\n");
+               return -1;
+       }
+
+       parse = ast_strdupa(data);
+       AST_STANDARD_APP_ARGS(args, parse);
+       
+       session.caller_mode = FALSE;
+
+       if (args.options) {
+               if (strchr(args.options, 'c'))
+                       session.caller_mode = TRUE;
+       }
+
+       /* Done parsing */
+       session.direction = 0;
+       session.file_name = args.file_name;
+       session.chan = chan;
+       session.finished = 0;
+
+       res = transmit(&session);
+
+       return res;
+}
+
+static int unload_module(void)
+{
+       int res;
+
+       res = ast_unregister_application(app_sndfax_name);      
+       res |= ast_unregister_application(app_rcvfax_name);     
+
+       return res;
+}
+
+static int load_module(void)
+{
+       int res ;
+
+       res = ast_register_application(app_sndfax_name, sndfax_exec, app_sndfax_synopsis, app_sndfax_desc);
+       res |= ast_register_application(app_rcvfax_name, rcvfax_exec, app_rcvfax_synopsis, app_rcvfax_desc);
+
+       /* The default SPAN message handler prints to stderr. It is something we do not want */
+       span_set_message_handler(NULL);
+
+       return res;
+}
+
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "Simple FAX Application",
+               .load = load_module,
+               .unload = unload_module,
+               );
+
+