SPAN_DECLARE_NONSTD(int) fax_rx_fillin(fax_state_t *s, int len)
{
/* To mitigate the effect of lost packets on a packet network we should
try to sustain the status quo. If there is no receive modem running, keep
things that way. If there is a receive modem running, try to sustain its
operation, without causing a phase hop, or letting its adaptive functions
diverge. */
#if defined(LOG_FAX_AUDIO)
if (s->modems.audio_rx_log >= 0)
{
int i;
#if defined(_MSC_VER)
int16_t *amp = (int16_t *) _alloca(sizeof(int16_t)*len);
#else
int16_t amp[len];
#endif
vec_zeroi16(amp, len);
write(s->modems.audio_rx_log, amp, len*sizeof(int16_t));
}
#endif
/* Call the fillin function of the current modem (if there is one). */
s->modems.rx_fillin_handler(s->modems.rx_fillin_user_data, len);
t30_timer_update(&s->t30, len);
return 0;
}
SPAN_DECLARE(int) fax_rx(fax_state_t *s, int16_t *amp, int len)
{
int i;
#if defined(LOG_FAX_AUDIO)
if (s->modems.audio_rx_log >= 0)
write(s->modems.audio_rx_log, amp, len*sizeof(int16_t));
#endif
for (i = 0; i < len; i++)
amp[i] = dc_restore(&s->modems.dc_restore, amp[i]);
s->modems.rx_handler(s->modems.rx_user_data, amp, len);
t30_timer_update(&s->t30, len);
return 0;
}
int fax_rx(fax_state_t *s, int16_t *amp, int len)
{
int i;
#if defined(LOG_FAX_AUDIO)
if (s->fax_audio_rx_log >= 0)
write(s->fax_audio_rx_log, amp, len*sizeof(int16_t));
#endif
for (i = 0; i < len; i++)
amp[i] = dc_restore(&(s->dc_restore), amp[i]);
s->rx_handler(s->rx_user_data, amp, len);
t30_timer_update(&(s->t30_state), len);
return 0;
}
SPAN_DECLARE(int) fax_rx_fillin(fax_state_t *s, int len)
{
/* To mitigate the effect of lost packets on a packet network we should
try to sustain the status quo. If there is no receive modem running, keep
things that way. If there is a receive modem running, try to sustain its
operation, without causing a phase hop, or letting its adaptive functions
diverge. */
#if defined(LOG_FAX_AUDIO)
if (s->modems.audio_rx_log >= 0)
{
int i;
#if defined(_MSC_VER)
int16_t *amp = (int16_t *) _alloca(sizeof(int16_t)*len);
#else
int16_t amp[len];
#endif
vec_zeroi16(amp, len);
write(s->modems.audio_rx_log, amp, len*sizeof(int16_t));
}
#endif
t30_timer_update(&s->t30, len);
/* Call the fillin function of the current modem (if there is one). */
switch (s->modems.current_rx_type)
{
case T30_MODEM_V21:
len = fsk_rx_fillin(&s->modems.v21_rx, len);
break;
case T30_MODEM_V27TER:
/* TODO: what about FSK in the early stages */
len = v27ter_rx_fillin(&s->modems.v27ter_rx, len);
break;
case T30_MODEM_V29:
/* TODO: what about FSK in the early stages */
len = v29_rx_fillin(&s->modems.v29_rx, len);
break;
case T30_MODEM_V17:
/* TODO: what about FSK in the early stages */
len = v17_rx_fillin(&s->modems.v17_rx, len);
break;
}
return len;
}
int t38_terminal_send_timeout(t38_terminal_state_t *s, int samples)
{
int len;
int i;
int previous;
uint8_t buf[MAX_OCTETS_PER_UNPACED_CHUNK + 50];
/* Training times for all the modem options, with and without TEP */
static const int training_time[] =
{
0, 0, /* T38_IND_NO_SIGNAL */
0, 0, /* T38_IND_CNG */
0, 0, /* T38_IND_CED */
1000, 1000, /* T38_IND_V21_PREAMBLE */ /* TODO: 850 should be OK for this, but it causes trouble with some ATAs. Why? */
943, 1158, /* T38_IND_V27TER_2400_TRAINING */
708, 923, /* T38_IND_V27TER_4800_TRAINING */
234, 454, /* T38_IND_V29_7200_TRAINING */
234, 454, /* T38_IND_V29_9600_TRAINING */
142, 367, /* T38_IND_V17_7200_SHORT_TRAINING */
1393, 1618, /* T38_IND_V17_7200_LONG_TRAINING */
142, 367, /* T38_IND_V17_9600_SHORT_TRAINING */
1393, 1618, /* T38_IND_V17_9600_LONG_TRAINING */
142, 367, /* T38_IND_V17_12000_SHORT_TRAINING */
1393, 1618, /* T38_IND_V17_12000_LONG_TRAINING */
142, 367, /* T38_IND_V17_14400_SHORT_TRAINING */
1393, 1618, /* T38_IND_V17_14400_LONG_TRAINING */
0, 0, /* T38_IND_V8_ANSAM */
0, 0, /* T38_IND_V8_SIGNAL */
0, 0, /* T38_IND_V34_CNTL_CHANNEL_1200 */
0, 0, /* T38_IND_V34_PRI_CHANNEL */
0, 0, /* T38_IND_V34_CC_RETRAIN */
0, 0, /* T38_IND_V33_12000_TRAINING */
0, 0 /* T38_IND_V33_14400_TRAINING */
};
if (s->current_rx_type == T30_MODEM_DONE || s->current_tx_type == T30_MODEM_DONE)
return TRUE;
s->samples += samples;
t30_timer_update(&s->t30_state, samples);
if (s->timeout_rx_samples && s->samples > s->timeout_rx_samples)
{
span_log(&s->logging, SPAN_LOG_FLOW, "Timeout mid-receive\n");
s->timeout_rx_samples = 0;
t30_receive_complete(&(s->t30_state));
}
if (s->timed_step == T38_TIMED_STEP_NONE)
return FALSE;
if (s->samples < s->next_tx_samples)
return FALSE;
/* Its time to send something */
switch (s->timed_step)
{
case T38_TIMED_STEP_NON_ECM_MODEM:
/* Create a 75ms silence */
if (s->t38.current_tx_indicator != T38_IND_NO_SIGNAL)
t38_core_send_indicator(&s->t38, T38_IND_NO_SIGNAL, s->indicator_tx_count);
s->timed_step = T38_TIMED_STEP_NON_ECM_MODEM_2;
s->next_tx_samples += ms_to_samples(75);
break;
case T38_TIMED_STEP_NON_ECM_MODEM_2:
/* Switch on a fast modem, and give the training time to complete */
t38_core_send_indicator(&s->t38, s->next_tx_indicator, s->indicator_tx_count);
s->timed_step = T38_TIMED_STEP_NON_ECM_MODEM_3;
s->next_tx_samples += ms_to_samples(training_time[s->next_tx_indicator << 1]);
break;
case T38_TIMED_STEP_NON_ECM_MODEM_3:
/* Send a chunk of non-ECM image data */
/* T.38 says it is OK to send the last of the non-ECM data in the signal end message.
However, I think the early versions of T.38 said the signal end message should not
contain data. Hopefully, following the current spec will not cause compatibility
issues. */
len = t30_non_ecm_get_chunk(&s->t30_state, buf, s->octets_per_data_packet);
bit_reverse(buf, buf, len);
if (len >= s->octets_per_data_packet)
{
s->next_tx_samples += ms_to_samples(s->ms_per_tx_chunk);
t38_core_send_data(&s->t38, s->current_tx_data_type, T38_FIELD_T4_NON_ECM_DATA, buf, len, DATA_TX_COUNT);
}
else
{
t38_core_send_data(&s->t38, s->current_tx_data_type, T38_FIELD_T4_NON_ECM_SIG_END, buf, len, s->data_end_tx_count);
/* This should not be needed, since the message above indicates the end of the signal, but it
seems like it can improve compatibility with quirky implementations. */
t38_core_send_indicator(&s->t38, T38_IND_NO_SIGNAL, s->indicator_tx_count);
s->timed_step = T38_TIMED_STEP_NONE;
t30_send_complete(&(s->t30_state));
}
break;
case T38_TIMED_STEP_HDLC_MODEM:
/* Send HDLC preambling */
t38_core_send_indicator(&s->t38, s->next_tx_indicator, s->indicator_tx_count);
s->next_tx_samples += ms_to_samples(training_time[s->next_tx_indicator << 1]);
s->timed_step = T38_TIMED_STEP_HDLC_MODEM_2;
break;
case T38_TIMED_STEP_HDLC_MODEM_2:
/* Send a chunk of HDLC data */
i = s->octets_per_data_packet;
if (i >= (s->tx_len - s->tx_ptr))
{
i = s->tx_len - s->tx_ptr;
s->timed_step = T38_TIMED_STEP_HDLC_MODEM_3;
}
t38_core_send_data(&s->t38, s->current_tx_data_type, T38_FIELD_HDLC_DATA, &s->tx_buf[s->tx_ptr], i, DATA_TX_COUNT);
s->tx_ptr += i;
s->next_tx_samples += ms_to_samples(s->ms_per_tx_chunk);
break;
case T38_TIMED_STEP_HDLC_MODEM_3:
/* End of HDLC frame */
previous = s->current_tx_data_type;
s->tx_ptr = 0;
s->tx_len = 0;
t30_send_complete(&s->t30_state);
if (s->tx_len < 0)
{
t38_core_send_data(&s->t38, previous, T38_FIELD_HDLC_FCS_OK_SIG_END, NULL, 0, s->data_end_tx_count);
/* We have already sent T38_FIELD_HDLC_FCS_OK_SIG_END. It seems some boxes may not like
us sending a T38_FIELD_HDLC_SIG_END at this point. Just say there is no signal. */
t38_core_send_indicator(&s->t38, T38_IND_NO_SIGNAL, s->indicator_tx_count);
s->tx_len = 0;
t30_send_complete(&s->t30_state);
if (s->tx_len)
s->timed_step = T38_TIMED_STEP_HDLC_MODEM;
}
else
{
t38_core_send_data(&s->t38, previous, T38_FIELD_HDLC_FCS_OK, NULL, 0, DATA_TX_COUNT);
if (s->tx_len)
s->timed_step = T38_TIMED_STEP_HDLC_MODEM_2;
}
s->next_tx_samples += ms_to_samples(s->ms_per_tx_chunk);
break;
case T38_TIMED_STEP_CED:
/* It seems common practice to start with a no signal indicator, though
this is not a specified requirement. Since we should be sending 200ms
of silence, starting the delay with a no signal indication makes sense.
We do need a 200ms delay, as that is a specification requirement. */
s->timed_step = T38_TIMED_STEP_CED_2;
s->next_tx_samples = s->samples + ms_to_samples(200);
t38_core_send_indicator(&s->t38, T38_IND_NO_SIGNAL, s->indicator_tx_count);
s->current_tx_data_type = T38_DATA_NONE;
break;
case T38_TIMED_STEP_CED_2:
/* Initial 200ms delay over. Send the CED indicator */
s->next_tx_samples = s->samples + ms_to_samples(3000);
s->timed_step = T38_TIMED_STEP_PAUSE;
t38_core_send_indicator(&s->t38, T38_IND_CED, s->indicator_tx_count);
s->current_tx_data_type = T38_DATA_NONE;
break;
case T38_TIMED_STEP_CNG:
/* It seems common practice to start with a no signal indicator, though
this is not a specified requirement. Since we should be sending 200ms
of silence, starting the delay with a no signal indication makes sense.
We do need a 200ms delay, as that is a specification requirement. */
s->timed_step = T38_TIMED_STEP_CNG_2;
s->next_tx_samples = s->samples + ms_to_samples(200);
t38_core_send_indicator(&s->t38, T38_IND_NO_SIGNAL, s->indicator_tx_count);
s->current_tx_data_type = T38_DATA_NONE;
break;
case T38_TIMED_STEP_CNG_2:
/* Initial short delay over. Send the CNG indicator */
s->timed_step = T38_TIMED_STEP_NONE;
t38_core_send_indicator(&s->t38, T38_IND_CNG, s->indicator_tx_count);
s->current_tx_data_type = T38_DATA_NONE;
break;
case T38_TIMED_STEP_PAUSE:
/* End of timed pause */
s->timed_step = T38_TIMED_STEP_NONE;
t30_send_complete(&s->t30_state);
break;
}
return FALSE;
}