From 9da5a46fcb8930047aefd2a3efc967b70785efe5 Mon Sep 17 00:00:00 2001
From: Richard Fuchs <rfuchs@sipwise.com>
Date: Wed, 6 Oct 2021 08:45:26 -0400
Subject: [PATCH] TT#136956 support DTMF-security=random

Change-Id: I4100c1511be743901d302491238872990f213118
---
 README.md                |  4 +++-
 daemon/call_interfaces.c |  3 +++
 daemon/codec.c           |  8 +++++++
 daemon/dtmf.c            |  1 +
 include/call.h           |  4 +++-
 lib/codeclib.c           | 22 ++++++++++++++++++++
 lib/codeclib.h           |  2 ++
 lib/dtmflib.c            | 45 +++++++++++++++++++++++++---------------
 lib/dtmflib.h            |  9 ++++++++
 9 files changed, 79 insertions(+), 19 deletions(-)

diff --git a/README.md b/README.md
index e1982f6ef..2a7fe8cde 100644
--- a/README.md
+++ b/README.md
@@ -1524,7 +1524,9 @@ Optionally included keys are:
 	Used in the `block DTMF` message to select the DTMF blocking mode. The
 	default mode is `drop` which simply drops DTMF event packets. The other
 	supported modes are: `silence` which replaces DTMF events with silence
-	audio; `tone` which replaces DTMF events with a single sine wave tone.
+	audio; `tone` which replaces DTMF events with a single sine wave tone;
+	`random` which replaces DTMF events with random other DTMF events (both
+	in-band DTMF audio tones and RFC event packets).
 
 * `delay-buffer`
 
diff --git a/daemon/call_interfaces.c b/daemon/call_interfaces.c
index 5900cfb43..b02bfd4ab 100644
--- a/daemon/call_interfaces.c
+++ b/daemon/call_interfaces.c
@@ -1335,6 +1335,9 @@ static void call_ng_main_flags(struct sdp_ng_flags *out, str *key, bencode_item_
 				case CSH_LOOKUP("tone"):
 					out->block_dtmf_mode = BLOCK_DTMF_TONE;
 					break;
+				case CSH_LOOKUP("random"):
+					out->block_dtmf_mode = BLOCK_DTMF_RANDOM;
+					break;
 				default:
 					ilog(LOG_WARN, "Unknown 'DTMF-security' flag encountered: '" STR_FORMAT "'",
 							STR_FMT(&s));
diff --git a/daemon/codec.c b/daemon/codec.c
index 50a1e9259..17545c6be 100644
--- a/daemon/codec.c
+++ b/daemon/codec.c
@@ -2390,6 +2390,14 @@ static void delay_frame_manipulate(struct delay_frame *dframe) {
 				frame_fill_tone_samples(frame->format, frame->extended_data[0], dframe->ts,
 						frame->nb_samples, 400, 10, frame->sample_rate, frame->channels);
 				break;
+			case BLOCK_DTMF_RANDOM:
+				if (!media->dtmf_event_state)
+					media->dtmf_event_state = '0' + (ssl_random() % 10);
+				frame_fill_dtmf_samples(frame->format, frame->extended_data[0], dframe->ts,
+						frame->nb_samples, media->dtmf_event_state - '0',
+						10, frame->sample_rate,
+						frame->channels);
+				break;
 			default:
 				break;
 		}
diff --git a/daemon/dtmf.c b/daemon/dtmf.c
index 9ac1e2015..c396dda7e 100644
--- a/daemon/dtmf.c
+++ b/daemon/dtmf.c
@@ -160,6 +160,7 @@ static void dtmf_code_event(struct call_media *media, char event, uint64_t ts) {
 	media->dtmf_code = event;
 	media->dtmf_start = ts;
 	media->dtmf_end = 0;
+	media->dtmf_event_state = 0;
 }
 
 
diff --git a/include/call.h b/include/call.h
index 39eb53fd2..c0916d3be 100644
--- a/include/call.h
+++ b/include/call.h
@@ -206,7 +206,8 @@ enum block_dtmf_mode {
 	BLOCK_DTMF___PCM_REPLACE_START = 2,
 	BLOCK_DTMF_SILENCE = 2,
 	BLOCK_DTMF_TONE = 3,
-	BLOCK_DTMF___PCM_REPLACE_END = 3,
+	BLOCK_DTMF_RANDOM = 4,
+	BLOCK_DTMF___PCM_REPLACE_END = 4,
 };
 
 
@@ -401,6 +402,7 @@ struct call_media {
 	uint32_t		dtmf_start;
 	char			dtmf_code;
 	uint32_t		dtmf_end;
+	unsigned int		dtmf_event_state;
 #ifdef WITH_TRANSCODING
 	union {
 		struct {
diff --git a/lib/codeclib.c b/lib/codeclib.c
index 0ef6dc152..f856a0fe6 100644
--- a/lib/codeclib.c
+++ b/lib/codeclib.c
@@ -2656,3 +2656,25 @@ void frame_fill_tone_samples(enum AVSampleFormat fmt, void *samples, unsigned in
 			break;
 	}
 }
+
+void frame_fill_dtmf_samples(enum AVSampleFormat fmt, void *samples, unsigned int offset, unsigned int num,
+		unsigned int event, unsigned int volume, unsigned int sample_rate, unsigned int channels)
+{
+	switch (fmt) {
+		case AV_SAMPLE_FMT_S16:
+			dtmf_samples_int16_t(samples, offset, num, event, volume, sample_rate, channels);
+			break;
+		case AV_SAMPLE_FMT_S32:
+			dtmf_samples_int32_t(samples, offset, num, event, volume, sample_rate, channels);
+			break;
+		case AV_SAMPLE_FMT_DBL:
+			dtmf_samples_double(samples, offset, num, event, volume, sample_rate, channels);
+			break;
+		case AV_SAMPLE_FMT_FLT:
+			dtmf_samples_float(samples, offset, num, event, volume, sample_rate, channels);
+			break;
+		default:
+			ilog(LOG_ERR | LOG_FLAG_LIMIT, "Unsupported sample format %u", fmt);
+			break;
+	}
+}
diff --git a/lib/codeclib.h b/lib/codeclib.h
index 9e6e9459d..b66321063 100644
--- a/lib/codeclib.h
+++ b/lib/codeclib.h
@@ -343,6 +343,8 @@ int packet_sequencer_insert(packet_sequencer_t *ps, seq_packet_t *);
 
 void frame_fill_tone_samples(enum AVSampleFormat fmt, void *samples, unsigned int offset, unsigned int num,
 		unsigned int freq, unsigned int volume, unsigned int sample_rate, unsigned int channels);
+void frame_fill_dtmf_samples(enum AVSampleFormat fmt, void *samples, unsigned int offset, unsigned int num,
+		unsigned int event, unsigned int volume, unsigned int sample_rate, unsigned int channels);
 
 
 #include "auxlib.h"
diff --git a/lib/dtmflib.c b/lib/dtmflib.c
index 02ea025e7..3392238e4 100644
--- a/lib/dtmflib.c
+++ b/lib/dtmflib.c
@@ -221,24 +221,35 @@ tone_samples_x(int32_t)
 tone_samples_x(double)
 tone_samples_x(float)
 
+#define dtmf_samples_x(type) \
+void dtmf_samples_ ## type(type *samples, unsigned long offset, unsigned long num, unsigned int event, \
+		unsigned int volume, unsigned int sample_rate, unsigned int channels) \
+{ \
+	const struct dtmf_freq *df; \
+\
+	if (event == 0xff) { \
+		/* pause - silence samples */ \
+		memset(samples, 0, num * sizeof(type)); \
+		return; \
+	} \
+\
+	if (event >= G_N_ELEMENTS(dtmf_freqs)) { \
+		ilog(LOG_WARN | LOG_FLAG_LIMIT, "Unsupported DTMF event %u", event); \
+		memset(samples, 0, num * sizeof(type)); \
+		return; \
+	} \
+	df = &dtmf_freqs[event]; \
+\
+	freq_samples_ ## type(samples, offset, num, df->prim, df->sec, volume, sample_rate, channels); \
+} \
+
+dtmf_samples_x(int16_t)
+dtmf_samples_x(int32_t)
+dtmf_samples_x(double)
+dtmf_samples_x(float)
+
 void dtmf_samples_int16_t_mono(void *buf, unsigned long offset, unsigned long num, unsigned int event,
 		unsigned int volume, unsigned int sample_rate)
 {
-	int16_t *samples = buf;
-	const struct dtmf_freq *df;
-
-	if (event == 0xff) {
-		// pause - silence samples
-		memset(samples, 0, num * 2);
-		return;
-	}
-
-	if (event >= G_N_ELEMENTS(dtmf_freqs)) {
-		ilog(LOG_WARN | LOG_FLAG_LIMIT, "Unsupported DTMF event %u", event);
-		memset(buf, 0, num * 2);
-		return;
-	}
-	df = &dtmf_freqs[event];
-
-	freq_samples_int16_t(samples, offset, num, df->prim, df->sec, volume, sample_rate, 1);
+	dtmf_samples_int16_t(buf, offset, num, event, volume, sample_rate, 1);
 }
diff --git a/lib/dtmflib.h b/lib/dtmflib.h
index db0decb46..ba9e05019 100644
--- a/lib/dtmflib.h
+++ b/lib/dtmflib.h
@@ -35,5 +35,14 @@ void tone_samples_double(double *buf, unsigned long offset, unsigned long num, u
 void tone_samples_float(float *buf, unsigned long offset, unsigned long num, unsigned int freq,
 		unsigned int volume, unsigned int sample_rate, unsigned int channels);
 
+void dtmf_samples_int16_t(int16_t *buf, unsigned long offset, unsigned long num, unsigned int event,
+		unsigned int volume, unsigned int sample_rate, unsigned int channels);
+void dtmf_samples_int32_t(int32_t *buf, unsigned long offset, unsigned long num, unsigned int event,
+		unsigned int volume, unsigned int sample_rate, unsigned int channels);
+void dtmf_samples_double(double *buf, unsigned long offset, unsigned long num, unsigned int event,
+		unsigned int volume, unsigned int sample_rate, unsigned int channels);
+void dtmf_samples_float(float *buf, unsigned long offset, unsigned long num, unsigned int event,
+		unsigned int volume, unsigned int sample_rate, unsigned int channels);
+
 
 #endif