Some cleanups of FAX modem tone handling

libs/spandsp/src/at_interpreter.c

@@ -291,7 +291,7 @@ SPAN_DECLARE(void) at_call_event(at_state_t *s, int event)
         {
             /* FAX modem connection */
             at_set_at_rx_mode(s, AT_MODE_DELIVERY);
-            at_modem_control(s, AT_MODEM_CONTROL_RESTART, (void *) FAX_MODEM_CED_TONE);
+            at_modem_control(s, AT_MODEM_CONTROL_RESTART, (void *) FAX_MODEM_CED_TONE_TX);
         }
         break;
     case AT_CALL_EVENT_CONNECTED:
@@ -315,9 +315,9 @@ SPAN_DECLARE(void) at_call_event(at_state_t *s, int event)
                 /* FAX modem connection */
                 at_set_at_rx_mode(s, AT_MODE_DELIVERY);
                 if (s->silent_dial)
-                    at_modem_control(s, AT_MODEM_CONTROL_RESTART, (void *) FAX_MODEM_NOCNG_TONE);
+                    at_modem_control(s, AT_MODEM_CONTROL_RESTART, (void *) FAX_MODEM_NOCNG_TONE_TX);
                 else
-                    at_modem_control(s, AT_MODEM_CONTROL_RESTART, (void *) FAX_MODEM_CNG_TONE);
+                    at_modem_control(s, AT_MODEM_CONTROL_RESTART, (void *) FAX_MODEM_CNG_TONE_TX);
                 s->dte_is_waiting = TRUE;
             }
         }

libs/spandsp/src/fax.c

@@ -323,12 +323,8 @@ static void fax_set_tx_type(void *user_data, int type, int bit_rate, int short_t
         break;
     case T30_MODEM_CED:
     case T30_MODEM_CNG:
-        if (type == T30_MODEM_CED)
-            tone = MODEM_CONNECT_TONES_FAX_CED;
-        else
-            tone = MODEM_CONNECT_TONES_FAX_CNG;
-        modem_connect_tones_tx_init(&t->connect_tx, tone);
-        fax_modems_set_tx_handler(t, (span_tx_handler_t) &modem_connect_tones_tx, &t->connect_tx);
+        tone = (type == T30_MODEM_CED)  ?  FAX_MODEM_CED_TONE_TX  :  FAX_MODEM_CNG_TONE_TX;
+        fax_modems_start_slow_modem(t, tone);
         fax_modems_set_next_tx_handler(t, (span_tx_handler_t) NULL, NULL);
         t->transmit = TRUE;
         break;

libs/spandsp/src/fax_modems.c

@@ -261,11 +261,32 @@ SPAN_DECLARE(void) fax_modems_start_slow_modem(fax_modems_state_t *s, int which)
     {
     case FAX_MODEM_V21_RX:
         fsk_rx_init(&s->v21_rx, &preset_fsk_specs[FSK_V21CH2], FSK_FRAME_MODE_SYNC, (put_bit_func_t) hdlc_rx_put_bit, &s->hdlc_rx);
+        fax_modems_set_rx_handler(s, (span_rx_handler_t) &fsk_rx, &s->v21_rx, (span_rx_fillin_handler_t) &fsk_rx_fillin, &s->v21_rx);
         fsk_rx_signal_cutoff(&s->v21_rx, -39.09f);
         s->rx_frame_received = FALSE;
         break;
+    case FAX_MODEM_CED_TONE_RX:
+        modem_connect_tones_rx_init(&s->connect_rx, MODEM_CONNECT_TONES_FAX_CED, s->tone_callback, s->tone_callback_user_data);
+        fax_modems_set_rx_handler(s, (span_rx_handler_t) &modem_connect_tones_rx, &s->connect_rx, (span_rx_fillin_handler_t) &modem_connect_tones_rx_fillin, &s->connect_rx);
+        break;
+    case FAX_MODEM_CNG_TONE_RX:
+        modem_connect_tones_rx_init(&s->connect_rx, MODEM_CONNECT_TONES_FAX_CNG, s->tone_callback, s->tone_callback_user_data);
+        fax_modems_set_rx_handler(s, (span_rx_handler_t) &modem_connect_tones_rx, &s->connect_rx, (span_rx_fillin_handler_t) &modem_connect_tones_rx_fillin, &s->connect_rx);
+        break;
     case FAX_MODEM_V21_TX:
         fsk_tx_init(&s->v21_tx, &preset_fsk_specs[FSK_V21CH2], (get_bit_func_t) hdlc_tx_get_bit, &s->hdlc_tx);
+        fax_modems_set_tx_handler(s, (span_tx_handler_t) &fsk_tx, &s->v21_tx);
+        fax_modems_set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
+        break;
+    case FAX_MODEM_CED_TONE_TX:
+        modem_connect_tones_tx_init(&s->connect_tx, MODEM_CONNECT_TONES_FAX_CED);
+        fax_modems_set_tx_handler(s, (span_tx_handler_t) &modem_connect_tones_tx, &s->connect_tx);
+        fax_modems_set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
+        break;
+    case FAX_MODEM_CNG_TONE_TX:
+        modem_connect_tones_tx_init(&s->connect_tx, MODEM_CONNECT_TONES_FAX_CNG);
+        fax_modems_set_tx_handler(s, (span_tx_handler_t) &modem_connect_tones_tx, &s->connect_tx);
+        fax_modems_set_next_tx_handler(s, (span_tx_handler_t) NULL, NULL);
         break;
     }
 }
@@ -490,12 +511,14 @@ SPAN_DECLARE(fax_modems_state_t *) fax_modems_init(fax_modems_state_t *s,
     s->use_tep = use_tep;
 
     modem_connect_tones_tx_init(&s->connect_tx, MODEM_CONNECT_TONES_FAX_CNG);
+    s->tone_callback = tone_callback;
+    s->tone_callback_user_data = user_data;
     if (tone_callback)
     {
         modem_connect_tones_rx_init(&s->connect_rx,
                                     MODEM_CONNECT_TONES_FAX_CNG,
-                                    tone_callback,
-                                    user_data);
+                                    s->tone_callback,
+                                    s->tone_callback_user_data);
     }
     /*endif*/
     span_log_init(&s->logging, SPAN_LOG_NONE, NULL);

libs/spandsp/src/modem_connect_tones.c

@@ -693,6 +693,12 @@ SPAN_DECLARE_NONSTD(int) modem_connect_tones_rx(modem_connect_tones_rx_state_t *
 }
 /*- End of function --------------------------------------------------------*/
 
+SPAN_DECLARE_NONSTD(int) modem_connect_tones_rx_fillin(modem_connect_tones_rx_state_t *s, int len)
+{
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+
 SPAN_DECLARE(int) modem_connect_tones_rx_get(modem_connect_tones_rx_state_t *s)
 {
     int x;

libs/spandsp/src/spandsp/fax_modems.h

@@ -34,9 +34,11 @@ enum
     FAX_MODEM_FLUSH = 0,
     FAX_MODEM_SILENCE_TX,
     FAX_MODEM_SILENCE_RX,
-    FAX_MODEM_CED_TONE,
-    FAX_MODEM_CNG_TONE,
-    FAX_MODEM_NOCNG_TONE,
+    FAX_MODEM_CED_TONE_TX,
+    FAX_MODEM_CNG_TONE_TX,
+    FAX_MODEM_NOCNG_TONE_TX,
+    FAX_MODEM_CED_TONE_RX,
+    FAX_MODEM_CNG_TONE_RX,
     FAX_MODEM_V21_TX,
     FAX_MODEM_V17_TX,
     FAX_MODEM_V27TER_TX,

libs/spandsp/src/spandsp/modem_connect_tones.h

@@ -141,7 +141,16 @@ SPAN_DECLARE_NONSTD(int) modem_connect_tones_tx(modem_connect_tones_tx_state_t *
 SPAN_DECLARE_NONSTD(int) modem_connect_tones_rx(modem_connect_tones_rx_state_t *s,
                                                 const int16_t amp[],
                                                 int len);
-                             
+
+/*! Fake processing of a missing block of received modem connect tone samples
+    (e.g due to packet loss).
+    \brief Fake processing of a missing block of received modem connect tone samples.
+    \param s The context.
+    \param len The number of samples to fake.
+    \return The number of samples unprocessed.
+*/
+SPAN_DECLARE_NONSTD(int) modem_connect_tones_rx_fillin(modem_connect_tones_rx_state_t *s, int len);
+
 /*! \brief Test if a modem_connect tone has been detected.
     \param s The context.
     \return TRUE if tone is detected, else FALSE.

libs/spandsp/src/spandsp/private/fax_modems.h

@@ -82,6 +82,11 @@ struct fax_modems_state_s
     /*! \brief */
     dc_restore_state_t dc_restore;
 
+    /*! \brief The callback function used to report detected tones. */
+    tone_report_func_t tone_callback;
+    /*! \brief A user specified opaque pointer passed to the tone_callback function. */
+    void *tone_callback_user_data;
+
     /*! \brief The fast modem type currently in use */
     int fast_modem;
 

libs/spandsp/src/t31.c

@@ -187,7 +187,7 @@ static void hdlc_accept_frame(void *user_data, const uint8_t *msg, int len, int
 static void hdlc_accept_t38_frame(void *user_data, const uint8_t *msg, int len, int ok);
 static void hdlc_accept_non_ecm_frame(void *user_data, const uint8_t *msg, int len, int ok);
 static int silence_rx(void *user_data, const int16_t amp[], int len);
-static int cng_rx(void *user_data, const int16_t amp[], int len);
+static int initial_timed_rx(void *user_data, const int16_t amp[], int len);
 static void non_ecm_put_bit(void *user_data, int bit);
 static void non_ecm_put(void *user_data, const uint8_t buf[], int len);
 static int non_ecm_get(void *user_data, uint8_t buf[], int len);
@@ -223,7 +223,7 @@ static int front_end_status(t31_state_t *s, int status)
             }
             /*endif*/
             break;
-        case FAX_MODEM_CED_TONE:
+        case FAX_MODEM_CED_TONE_TX:
             /* Go directly to V.21/HDLC transmit. */
             s->modem = FAX_MODEM_NONE;
             restart_modem(s, FAX_MODEM_V21_TX);
@@ -1599,7 +1599,6 @@ static int non_ecm_get(void *user_data, uint8_t buf[], int len)
                 s->non_ecm_tx.final = FALSE;
                 /* This will put the modem into its shutdown sequence. When
                    it has finally shut down, an OK response will be sent. */
-                //return SIG_STATUS_END_OF_DATA;
                 return i;
             }
             /*endif*/
@@ -1679,7 +1678,7 @@ static void hdlc_rx_status(void *user_data, int status)
         s->audio.modems.rx_trained = TRUE;
         break;
     case SIG_STATUS_CARRIER_UP:
-        if (s->modem == FAX_MODEM_CNG_TONE  ||  s->modem == FAX_MODEM_NOCNG_TONE  ||  s->modem == FAX_MODEM_V21_RX)
+        if (s->modem == FAX_MODEM_CNG_TONE_TX  ||  s->modem == FAX_MODEM_NOCNG_TONE_TX  ||  s->modem == FAX_MODEM_V21_RX)
         {
             s->at_state.rx_signal_present = TRUE;
             s->rx_frame_received = FALSE;
@@ -1718,7 +1717,7 @@ static void hdlc_rx_status(void *user_data, int status)
         s->audio.modems.rx_trained = FALSE;
         break;
     case SIG_STATUS_FRAMING_OK:
-        if (s->modem == FAX_MODEM_CNG_TONE  ||  s->modem == FAX_MODEM_NOCNG_TONE)
+        if (s->modem == FAX_MODEM_CNG_TONE_TX  ||  s->modem == FAX_MODEM_NOCNG_TONE_TX)
         {
             /* Once we get any valid HDLC the CNG tone stops, and we drop
                to the V.21 receive modem on its own. */
@@ -2028,7 +2027,7 @@ static int restart_modem(t31_state_t *s, int new_modem)
     use_hdlc = FALSE;
     switch (s->modem)
     {
-    case FAX_MODEM_CNG_TONE:
+    case FAX_MODEM_CNG_TONE_TX:
         if (s->t38_mode)
         {
             s->t38_fe.next_tx_samples = s->t38_fe.samples;
@@ -2037,35 +2036,34 @@ static int restart_modem(t31_state_t *s, int new_modem)
         }
         else
         {
-            modem_connect_tones_tx_init(&t->connect_tx, MODEM_CONNECT_TONES_FAX_CNG);
+            fax_modems_start_slow_modem(t, FAX_MODEM_CNG_TONE_TX);
             /* CNG is special, since we need to receive V.21 HDLC messages while sending the
                tone. Everything else in FAX processing sends only one way at a time. */
             /* Do V.21/HDLC receive in parallel. The other end may send its
                first message at any time. The CNG tone will continue until
                we get a valid preamble. */
             t31_v21_rx(s);
-            fax_modems_set_rx_handler(t, (span_rx_handler_t) &cng_rx, s, (span_rx_fillin_handler_t) &span_dummy_rx_fillin, NULL);
-            fax_modems_set_tx_handler(t, (span_tx_handler_t) &modem_connect_tones_tx, &t->connect_tx);
+            fax_modems_set_rx_handler(t, (span_rx_handler_t) &initial_timed_rx, s, (span_rx_fillin_handler_t) &span_dummy_rx_fillin, NULL);
             fax_modems_set_next_tx_handler(t, (span_tx_handler_t) NULL, NULL);
         }
         /*endif*/
         s->at_state.transmit = TRUE;
         break;
-    case FAX_MODEM_NOCNG_TONE:
+    case FAX_MODEM_NOCNG_TONE_TX:
         if (s->t38_mode)
         {
         }
         else
         {
             t31_v21_rx(s);
-            fax_modems_set_rx_handler(t, (span_rx_handler_t) &cng_rx, s, (span_rx_fillin_handler_t) &span_dummy_rx_fillin, NULL);
+            fax_modems_set_rx_handler(t, (span_rx_handler_t) &initial_timed_rx, s, (span_rx_fillin_handler_t) &span_dummy_rx_fillin, NULL);
             silence_gen_set(&t->silence_gen, 0);
             fax_modems_set_tx_handler(t, (span_tx_handler_t) &silence_gen, &t->silence_gen);
         }
         /*endif*/
         s->at_state.transmit = FALSE;
         break;
-    case FAX_MODEM_CED_TONE:
+    case FAX_MODEM_CED_TONE_TX:
         if (s->t38_mode)
         {
             s->t38_fe.next_tx_samples = s->t38_fe.samples;
@@ -2074,8 +2072,7 @@ static int restart_modem(t31_state_t *s, int new_modem)
         }
         else
         {
-            modem_connect_tones_tx_init(&t->connect_tx, MODEM_CONNECT_TONES_FAX_CED);
-            fax_modems_set_tx_handler(t, (span_tx_handler_t) &modem_connect_tones_tx, &t->connect_tx);
+            fax_modems_start_slow_modem(t, FAX_MODEM_CED_TONE_TX);
             fax_modems_set_next_tx_handler(t, (span_tx_handler_t) NULL, NULL);
         }
         /*endif*/
@@ -2121,9 +2118,9 @@ static int restart_modem(t31_state_t *s, int new_modem)
     case FAX_MODEM_V29_RX:
         if (!s->t38_mode)
         {
-            fax_modems_start_fast_modem(t, s->modem, s->bit_rate, s->short_train, use_hdlc);
             /* Allow for +FCERROR/+FRH:3 */
             t31_v21_rx(s);
+            fax_modems_start_fast_modem(t, s->modem, s->bit_rate, s->short_train, use_hdlc);
         }
         /*endif*/
         s->at_state.transmit = FALSE;
@@ -2743,7 +2740,7 @@ static int silence_rx(void *user_data, const int16_t amp[], int len)
 }
 /*- End of function --------------------------------------------------------*/
 
-static int cng_rx(void *user_data, const int16_t amp[], int len)
+static int initial_timed_rx(void *user_data, const int16_t amp[], int len)
 {
     t31_state_t *s;
 
@@ -2755,12 +2752,9 @@ static int cng_rx(void *user_data, const int16_t amp[], int len)
         restart_modem(s, FAX_MODEM_SILENCE_TX);
         at_modem_control(&s->at_state, AT_MODEM_CONTROL_HANGUP, NULL);
         t31_set_at_rx_mode(s, AT_MODE_ONHOOK_COMMAND);
+        return 0;
     }
-    else
-    {
-        fsk_rx(&s->audio.modems.v21_rx, amp, len);
-    }
-    /*endif*/
+    fsk_rx(&s->audio.modems.v21_rx, amp, len);
     return 0;
 }
 /*- End of function --------------------------------------------------------*/

libs/spandsp/src/t38_core.c

@@ -867,7 +867,7 @@ static int t38_encode_data(t38_core_state_t *s, uint8_t buf[], int data_type, co
 
     if (s->data_transport_protocol == T38_TRANSPORT_TCP_TPKT)
     {
-        /* Fill in the TPKT header (se RFC1006) */
+        /* Fill in the TPKT header (see RFC1006) */
         /* Version */
         buf[0] = 3;
         /* Reserved */

libs/spandsp/src/t38_gateway.c

@@ -321,16 +321,14 @@ static int set_next_tx_type(t38_gateway_state_t *s)
         break;
     case T38_IND_CNG:
         t->tx_bit_rate = 0;
-        modem_connect_tones_tx_init(&t->connect_tx, MODEM_CONNECT_TONES_FAX_CNG);
+        fax_modems_start_slow_modem(t, FAX_MODEM_CNG_TONE_TX);
         silence_gen_set(&t->silence_gen, 0);
-        fax_modems_set_tx_handler(t, (span_tx_handler_t) &modem_connect_tones_tx, &t->connect_tx);
         fax_modems_set_next_tx_handler(t, (span_tx_handler_t) &silence_gen, &t->silence_gen);
         fax_modems_set_rx_active(t, TRUE);
         break;
     case T38_IND_CED:
         t->tx_bit_rate = 0;
-        modem_connect_tones_tx_init(&t->connect_tx, MODEM_CONNECT_TONES_FAX_CED);
-        fax_modems_set_tx_handler(t, (span_tx_handler_t) &modem_connect_tones_tx, &t->connect_tx);
+        fax_modems_start_slow_modem(t, FAX_MODEM_CED_TONE_TX);
         fax_modems_set_next_tx_handler(t, (span_tx_handler_t) NULL, NULL);
         fax_modems_set_rx_active(t, TRUE);
         break;