srtp: add srtp support to mediastreamer

include/mediastreamer2/mediastream.h

@@ -31,6 +31,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 #include <ortp/ortp.h>
 #include <ortp/event.h>
 #include <ortp/zrtp.h>
+#include <ortp/srtp.h>
 
 
 #define PAYLOAD_TYPE_FLAG_CAN_RECV	PAYLOAD_TYPE_USER_FLAG_1
@@ -74,6 +75,7 @@ struct _AudioStream
 	bool_t use_rc;
 	bool_t is_beginning;
 	OrtpZrtpContext *ortpZrtpContext;
+	srtp_t srtp_session;
 };
 
 #ifdef __cplusplus
@@ -183,6 +185,8 @@ MS2_PUBLIC float audio_stream_get_average_quality_rating(AudioStream *stream);
 /* enable ZRTP on the audio stream */
 MS2_PUBLIC void audio_stream_enable_zrtp(AudioStream *stream, OrtpZrtpParams *params);
 
+/* enable SRTP on the audio stream */
+MS2_PUBLIC bool_t audio_stream_enable_strp(AudioStream* stream, enum ortp_srtp_crypto_suite_t suite, const char* snd_key, const char* rcv_key);
 
 /*****************
   Video Support
@@ -231,6 +235,7 @@ struct _VideoStream
 	bool_t adapt_bitrate;
 	int device_orientation; /* warning: meaning of this variable depends on the platform (Android, iOS, ...) */
 	OrtpZrtpContext *ortpZrtpContext;
+	srtp_t srtp_session;
 };
 
 typedef struct _VideoStream VideoStream;
@@ -277,6 +282,9 @@ MS2_PUBLIC void video_stream_send_only_stop(VideoStream *vs);
 /* enable ZRTP on the video stream using information from the audio stream */
 MS2_PUBLIC void video_stream_enable_zrtp(VideoStream *vstream, AudioStream *astream, OrtpZrtpParams *param);
 
+/* enable SRTP on the video stream */
+MS2_PUBLIC bool_t video_stream_enable_strp(VideoStream* stream, enum ortp_srtp_crypto_suite_t suite, const char* snd_key, const char* rcv_key);
+
 
 /**
  * Small API to display a local preview window.

src/audiostream.c

@@ -40,7 +40,6 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 #endif
 #endif
 
-
 #define MAX_RTP_SIZE	1500
 
 
@@ -788,3 +787,33 @@ MS2_PUBLIC float audio_stream_get_average_quality_rating(AudioStream *stream){
 void audio_stream_enable_zrtp(AudioStream *stream, OrtpZrtpParams *params){
 	stream->ortpZrtpContext=ortp_zrtp_context_new(stream->session, params);
 }
+
+bool_t audio_stream_enable_strp(AudioStream* stream, enum ortp_srtp_crypto_suite_t suite, const char* snd_key, const char* rcv_key) {
+	// assign new srtp transport to stream->session
+	// with 2 Master Keys
+	RtpTransport *rtp_tpt, *rtcp_tpt;	
+	
+	if (!ortp_srtp_supported()) {
+		ms_error("ortp srtp support not enabled");
+		return FALSE;
+	}
+	
+	ms_message("%s: stream=%p key='%s' key='%s'", __FUNCTION__,
+		stream, snd_key, rcv_key);
+	 
+	stream->srtp_session = ortp_srtp_create_configure_session(suite, 
+		rtp_session_get_send_ssrc(stream->session), 
+		snd_key, 
+		rcv_key); 
+	
+	if (!stream->srtp_session) {
+		return FALSE;
+	}
+	
+	// TODO: check who will free rtp_tpt ?
+	srtp_transport_new(stream->srtp_session, &rtp_tpt, &rtcp_tpt);
+	
+	rtp_session_set_transports(stream->session, rtp_tpt, rtcp_tpt);
+	
+	return TRUE;
+}

src/mscommon.c

@@ -31,6 +31,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
 #include "mediastreamer2/mscommon.h"
 #include "mediastreamer2/msfilter.h"
+#include <ortp/srtp.h>
 
 extern void __register_ffmpeg_encoders_if_possible(void);
 extern void ms_ffmpeg_check_init();
@@ -644,6 +645,9 @@ void ms_init(){
 		}
 	}
 #endif
+
+	ortp_srtp_init();
+
 	ms_message("ms_init() done");
 }
 

src/videostream.c

@@ -718,3 +718,33 @@ void video_stream_enable_zrtp(VideoStream *vstream, AudioStream *astream, OrtpZr
 		vstream->ortpZrtpContext=ortp_zrtp_multistream_new(astream->ortpZrtpContext, vstream->session, param);
 	}
 }
+
+bool_t video_stream_enable_strp(VideoStream* stream, enum ortp_srtp_crypto_suite_t suite, const char* snd_key, const char* rcv_key) {
+	// assign new srtp transport to stream->session
+	// with 2 Master Keys
+	RtpTransport *rtp_tpt, *rtcp_tpt;	
+	
+	if (!ortp_srtp_supported()) {
+		ms_error("ortp srtp support not enabled");
+		return FALSE;
+	}
+	
+	ms_message("%s: stream=%p key='%s' key='%s'", __FUNCTION__,
+		stream, snd_key, rcv_key);
+	 
+	stream->srtp_session = ortp_srtp_create_configure_session(suite, 
+		rtp_session_get_send_ssrc(stream->session), 
+		snd_key,
+		rcv_key); 
+	
+	if (!stream->srtp_session) {
+		return FALSE;
+	}
+	
+	// TODO: check who will free rtp_tpt ?
+	srtp_transport_new(stream->srtp_session, &rtp_tpt, &rtcp_tpt);
+	
+	rtp_session_set_transports(stream->session, rtp_tpt, rtcp_tpt);
+	
+	return TRUE;
+}

tests/mediastream.c

@@ -51,6 +51,8 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 #include <jni.h>
 #endif
 
+#include <ortp/b64.h>
+
 static int cond=1;
 
 
@@ -93,6 +95,9 @@ typedef struct _MediastreamDatas {
 	int preview_window_id;
 	/* starting values echo canceller */
 	int ec_len_ms, ec_delay_ms, ec_framesize;
+	bool_t enable_srtp;
+	char* srtp_local_master_key;
+	char* srtp_remote_master_key;
 	
 	AudioStream *audio;	
 	PayloadType *pt;
@@ -154,6 +159,7 @@ const char *usage="mediastream --local <port> --remote <ip:port> \n"
 								"[ --zrtp <zid> <secrets file> (enable zrtp) ]\n"
 								"[ --verbose (most verbose messages) ]\n"
 								"[ --video-windows-id <video surface:preview surface>]\n"
+								"[ --srtp <local master_key> <remote master_key> (enable srtp, master key is generated if absent from comand line)\n"
 		;
 
 
@@ -225,6 +231,8 @@ MediastreamDatas* init_default_args() {
 	args->preview_window_id = -1;
 	/* starting values echo canceller */
 	args->ec_len_ms=args->ec_delay_ms=args->ec_framesize=0;
+	args->enable_srtp = FALSE;
+	args->srtp_local_master_key = args->srtp_remote_master_key = NULL;
 
 	args->audio = NULL;
 	args->session = NULL;
@@ -354,7 +362,19 @@ bool_t parse_args(int argc, char** argv, MediastreamDatas* out) {
 		} else if (strcmp(argv[i], "--device-rotation")==0) {
 			i++;
 			out->device_rotation=atoi(argv[i]);
-		}else if (strcmp(argv[i],"--help")==0){
+		} else if (strcmp(argv[i], "--srtp")==0) {
+			if (!ortp_srtp_supported()) {
+				ms_error("ortp srtp support not enabled");
+				return FALSE;
+			}
+			out->enable_srtp = TRUE;
+			i++;
+			// check if we're being given keys
+			if (i + 1 < argc) {
+				out->srtp_local_master_key = argv[i++];
+				out->srtp_remote_master_key = argv[i++];
+			}
+		} else if (strcmp(argv[i],"--help")==0){
 			printf("%s",usage);
 			return FALSE;
 		}
@@ -408,6 +428,28 @@ void setup_media_streams(MediastreamDatas* args) {
 	if (args->fmtp!=NULL) payload_type_set_send_fmtp(args->pt,args->fmtp);
 	if (args->bitrate>0) args->pt->normal_bitrate=args->bitrate;
 
+	// do we need to generate srtp keys ?
+	if (args->enable_srtp) {
+		// default profile require key-length = 30 bytes
+		//  -> input : 40 b64 encoded bytes
+		if (!args->srtp_local_master_key) {
+			uint8_t tmp[30];			
+			crypto_get_random(tmp, 30);
+			args->srtp_local_master_key = (char*) malloc(41);
+			b64_encode((const char*)tmp, 30, args->srtp_local_master_key, 40);
+			args->srtp_local_master_key[40] = '\0';
+			ms_message("Generated local srtp key: '%s'", args->srtp_local_master_key);
+		}
+		if (!args->srtp_remote_master_key) {
+			uint8_t tmp[30];			
+			crypto_get_random(tmp, 30);
+			args->srtp_remote_master_key = (char*) malloc(41);
+			b64_encode((const char*)tmp, 30, args->srtp_remote_master_key, 40);
+			args->srtp_remote_master_key[40] = '\0';
+			ms_message("Generated remote srtp key: '%s'", args->srtp_remote_master_key);
+		}
+	}	
+
 	if (args->pt->type!=PAYLOAD_VIDEO){
 		MSSndCardManager *manager=ms_snd_card_manager_get();
 		MSSndCard *capt= args->capture_card==NULL ? ms_snd_card_manager_get_default_capture_card(manager) :
@@ -459,6 +501,15 @@ void setup_media_streams(MediastreamDatas* args) {
 
 			args->session=args->audio->session;
 		}
+		
+		if (args->enable_srtp) {
+			ms_message("SRTP enabled: %d", 
+				audio_stream_enable_strp(
+					args->audio, 
+					AES_128_SHA1_80,
+					args->srtp_local_master_key, 
+					args->srtp_remote_master_key));
+		}
 	}else{
 #ifdef VIDEO_ENABLED
 		if (args->eq){
@@ -485,6 +536,15 @@ void setup_media_streams(MediastreamDatas* args) {
 					args->jitter,cam
 					);
 		args->session=args->video->session;
+		
+		if (args->enable_srtp) {
+			ms_message("SRTP enabled: %d", 
+				video_stream_enable_strp(
+					args->video, 
+					AES_128_SHA1_80,
+					args->srtp_local_master_key, 
+					args->srtp_remote_master_key));
+		}
 #else
 		printf("Error: video support not compiled.\n");
 #endif