%FEATURE Add new feature to filter the SDP on bypass_media calls to remove or limit codecs.

VARIABLE: bypass_media_sdp_filter

Can be set globally or per leg on the inbound side of a bypass_media bridge.

VALID FILTERS:

remove(): Removes the specified codec if it exists in the SDP.
only():   Removes all codecs besides the one specified (providing that it exists in the sdp) (will not remove telephone-event))

EXAMPLE 1 (remove everything leaving only g729):

  <action application="set" data="bypass_media_sdp_filter=only(g729)"/>
  <action application="set" data="bypass_media=true"/>
  <action application="bridge" data="sofia/internal/1238@conference.freeswitch.org"/>

EXAMPLE 2 (remove everything leaving only g729 and also remove dtmf):

  <action application="set" data="bypass_media_sdp_filter=only(g729)|remove(telephone-event)"/>
  <action application="set" data="bypass_media=true"/>
  <action application="bridge" data="sofia/internal/1238@conference.freeswitch.org"/>

EXAMPLE 3 (remove alaw and speex):

  <action application="set" data="bypass_media_sdp_filter=remove(pcma)|remove(speex)"/>
  <action application="set" data="bypass_media=true"/>
  <action application="bridge" data="sofia/internal/1238@conference.freeswitch.org"/>

src/include/switch_channel.h

@@ -678,7 +678,8 @@ SWITCH_DECLARE(void) switch_channel_release_device_record(switch_device_record_t
 SWITCH_DECLARE(switch_status_t) switch_channel_bind_device_state_handler(switch_device_state_function_t function, void *user_data);
 SWITCH_DECLARE(switch_status_t) switch_channel_unbind_device_state_handler(switch_device_state_function_t function);
 SWITCH_DECLARE(const char *) switch_channel_device_state2str(switch_device_state_t device_state);
-								
+SWITCH_DECLARE(switch_status_t) switch_channel_pass_sdp(switch_channel_t *from_channel, switch_channel_t *to_channel, const char *sdp);
+
 SWITCH_END_EXTERN_C
 #endif
 /* For Emacs:

src/include/switch_core_media.h

@@ -275,7 +275,7 @@ SWITCH_DECLARE(payload_map_t *) switch_core_media_add_payload_map(switch_core_se
 SWITCH_DECLARE(switch_rtp_crypto_key_type_t) switch_core_media_crypto_str2type(const char *str);
 SWITCH_DECLARE(const char *) switch_core_media_crypto_type2str(switch_rtp_crypto_key_type_t type);
 SWITCH_DECLARE(int) switch_core_media_crypto_keylen(switch_rtp_crypto_key_type_t type);
-
+SWITCH_DECLARE(char *) switch_core_media_filter_sdp(const char *sdp, const char *cmd, const char *arg);
 
 SWITCH_END_EXTERN_C
 #endif

src/include/switch_utils.h

@@ -418,6 +418,7 @@ SWITCH_DECLARE(switch_status_t) switch_frame_alloc(switch_frame_t **frame, switc
 SWITCH_DECLARE(switch_status_t) switch_frame_dup(switch_frame_t *orig, switch_frame_t **clone);
 SWITCH_DECLARE(switch_status_t) switch_frame_free(switch_frame_t **frame);
 SWITCH_DECLARE(switch_bool_t) switch_is_number(const char *str);
+SWITCH_DECLARE(switch_bool_t) switch_is_leading_number(const char *str);
 SWITCH_DECLARE(char *) switch_find_parameter(const char *str, const char *param, switch_memory_pool_t *pool);
 
 /*!

src/mod/endpoints/mod_sofia/sofia.c

@@ -6567,9 +6567,8 @@ static void sofia_handle_sip_i_state(switch_core_session_t *session, int status,
 				}
 				if (switch_core_session_get_partner(session, &other_session) == SWITCH_STATUS_SUCCESS) {
 					other_channel = switch_core_session_get_channel(other_session);
-					if (!switch_channel_get_variable(other_channel, SWITCH_B_SDP_VARIABLE)) {
+					switch_channel_pass_sdp(channel, other_channel, r_sdp);
-						switch_channel_set_variable(other_channel, SWITCH_B_SDP_VARIABLE, r_sdp);
+
-					}
 					//switch_channel_pre_answer(other_channel);
 					switch_core_session_queue_indication(other_session, SWITCH_MESSAGE_INDICATE_PROGRESS);
 					switch_core_session_rwunlock(other_session);
@@ -6626,9 +6625,7 @@ static void sofia_handle_sip_i_state(switch_core_session_t *session, int status,
 					other_channel = switch_core_session_get_channel(other_session);
 					//other_tech_pvt = switch_core_session_get_private(other_session);
 
-					if (!switch_channel_get_variable(other_channel, SWITCH_B_SDP_VARIABLE)) {
+					switch_channel_pass_sdp(channel, other_channel, r_sdp);
-						switch_channel_set_variable(other_channel, SWITCH_B_SDP_VARIABLE, r_sdp);
-					}
 					switch_core_session_queue_indication(other_session, SWITCH_MESSAGE_INDICATE_ANSWER);
 					switch_core_session_rwunlock(other_session);
 				}
@@ -7114,10 +7111,8 @@ static void sofia_handle_sip_i_state(switch_core_session_t *session, int status,
 
 				if (switch_core_session_get_partner(session, &other_session) == SWITCH_STATUS_SUCCESS) {
 					other_channel = switch_core_session_get_channel(other_session);
-					if (!switch_channel_get_variable(other_channel, SWITCH_B_SDP_VARIABLE)) {
+					switch_channel_pass_sdp(channel, other_channel, r_sdp);
-						switch_channel_set_variable(other_channel, SWITCH_B_SDP_VARIABLE, r_sdp);
+					
-					}
-
 					if (sofia_test_flag(tech_pvt, TFLAG_3PCC) && sofia_test_pflag(profile, PFLAG_3PCC_PROXY)) {
 						switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG, "3PCC-PROXY, Got my ACK\n");
 						sofia_set_flag(tech_pvt, TFLAG_3PCC_HAS_ACK);
@@ -7218,10 +7213,8 @@ static void sofia_handle_sip_i_state(switch_core_session_t *session, int status,
 
 					if (switch_core_session_get_partner(session, &other_session) == SWITCH_STATUS_SUCCESS) {
 						other_channel = switch_core_session_get_channel(other_session);
-						if (!switch_channel_get_variable(other_channel, SWITCH_B_SDP_VARIABLE)) {
+						switch_channel_pass_sdp(channel, other_channel, r_sdp);
-							switch_channel_set_variable(other_channel, SWITCH_B_SDP_VARIABLE, r_sdp);
+						
-						}
-
 						//switch_channel_answer(other_channel);
 						switch_core_session_queue_indication(other_session, SWITCH_MESSAGE_INDICATE_ANSWER);
 

src/mod/endpoints/mod_verto/mod_verto.c

@@ -2401,7 +2401,8 @@ static void pass_sdp(verto_pvt_t *tech_pvt)
 
 	if (switch_core_session_get_partner(tech_pvt->session, &other_session) == SWITCH_STATUS_SUCCESS) {
 		other_channel = switch_core_session_get_channel(other_session);
-		switch_channel_set_variable(other_channel, SWITCH_B_SDP_VARIABLE, tech_pvt->r_sdp);
+		switch_channel_pass_sdp(tech_pvt->channel, other_channel, tech_pvt->r_sdp);
+
 		switch_channel_set_flag(other_channel, CF_PROXY_MODE);
 		switch_core_session_queue_indication(other_session, SWITCH_MESSAGE_INDICATE_ANSWER);
 		switch_core_session_rwunlock(other_session);

src/switch_channel.c

@@ -5220,6 +5220,65 @@ SWITCH_DECLARE(switch_status_t) switch_channel_unbind_device_state_handler(switc
 	return status;
 }
 
+SWITCH_DECLARE(switch_status_t) switch_channel_pass_sdp(switch_channel_t *from_channel, switch_channel_t *to_channel, const char *sdp)
+{
+	char *use_sdp = (char *) sdp;
+	char *patched_sdp = NULL;
+	switch_status_t status = SWITCH_STATUS_FALSE;
+
+	if (!switch_channel_get_variable(to_channel, SWITCH_B_SDP_VARIABLE)) {
+		const char *var;
+
+		if ((var = switch_channel_get_variable(from_channel, "bypass_media_sdp_filter"))) {
+			char *cmd = switch_core_session_strdup(from_channel->session, var);
+			int argc = 0;
+			char *argv[50];
+			int x = 0;
+
+			argc = switch_split(cmd, '|', argv);
+
+			for (x = 0; x < argc; x++) {
+				char *command = argv[x];
+				char *arg = strchr(command, '(');
+
+				if (arg) {
+					char *e = switch_find_end_paren(arg, '(', ')');
+					*arg++ = '\0';
+					if (e) *e = '\0';
+				}
+
+				if (zstr(command) || zstr(arg)) {
+					switch_log_printf(SWITCH_CHANNEL_CHANNEL_LOG(from_channel), SWITCH_LOG_WARNING, "%s SDP FILTER PARSE ERROR\n", from_channel->name);
+				} else {
+					char *tmp_sdp = NULL;
+
+					if (patched_sdp) {
+						tmp_sdp = switch_core_media_filter_sdp(patched_sdp, command, arg);
+					} else {
+						tmp_sdp = switch_core_media_filter_sdp(use_sdp, command, arg);
+					}
+
+
+					switch_log_printf(SWITCH_CHANNEL_CHANNEL_LOG(from_channel), SWITCH_LOG_DEBUG, 
+									  "Filter command %s(%s)\nFROM:\n==========\n%s\nTO:\n==========\n%s\n\n", 
+									  command, arg, patched_sdp ? patched_sdp : use_sdp, tmp_sdp);
+
+
+					if (tmp_sdp) {
+						switch_safe_free(patched_sdp);
+						patched_sdp = use_sdp = tmp_sdp;
+					}
+				}
+			}
+		}
+
+		switch_channel_set_variable(to_channel, SWITCH_B_SDP_VARIABLE, use_sdp);
+	}
+
+	switch_safe_free(patched_sdp);
+
+	return status;
+}
 
 /* For Emacs:
  * Local Variables:

src/switch_core_media.c

@@ -8854,6 +8854,220 @@ SWITCH_DECLARE(void) switch_core_media_deinit(void)
 	
 }
 
+static int payload_number(const char *name)
+{
+	if (!strcasecmp(name, "pcmu")) {
+		return 0;
+	}
+
+	if (!strcasecmp(name, "pcma")) {
+		return 8;
+	}
+
+	if (!strcasecmp(name, "gsm")) {
+		return 3;
+	}
+
+	if (!strcasecmp(name, "g722")) {
+		return 9;
+	}
+
+	if (!strcasecmp(name, "g729")) {
+		return 18;
+	}
+
+	if (!strcasecmp(name, "dvi4")) {
+		return 5;
+	}
+
+	if (!strcasecmp(name, "h261")) {
+		return 31;
+	}
+
+	if (!strcasecmp(name, "h263")) {
+		return 34;
+	}
+
+	return -1;
+}
+
+static int find_pt(const char *sdp, const char *name)
+{
+	const char *p;
+	
+	if ((p = switch_stristr(name, sdp))) {
+		if (p < end_of_p(sdp) && *(p+strlen(name)) == '/' && *(p-1) == ' ') {
+			p -= 2;
+
+			while(*p > 47 && *p < 58) {
+				p--;
+			}
+			p++;
+
+			if (p) {
+				return atoi(p);
+			}
+		}
+	}
+
+	return -1;
+}
+
+
+SWITCH_DECLARE(char *) switch_core_media_filter_sdp(const char *sdp_str, const char *cmd, const char *arg)
+{
+	char *new_sdp = NULL;
+	int pt = -1, te = -1;
+	switch_size_t len;
+	const char *i;
+	char *o;
+	int in_m = 0, m_tally = 0, slash = 0;
+	int number = 0, skip = 0;
+	int remove = !strcasecmp(cmd, "remove");
+	int only = !strcasecmp(cmd, "only");
+	char *end = end_of_p((char *)sdp_str);
+	int tst;
+	end++;
+
+	
+	if (remove || only) {
+		pt = payload_number(arg);
+		
+		if (pt < 0) {
+			pt = find_pt(sdp_str, arg);
+		}
+	} else {
+		return NULL;
+	}
+
+	if (only) {
+		te = find_pt(sdp_str, "telephone-event");
+	}
+
+
+	len = strlen(sdp_str);
+	new_sdp = malloc(len);
+	o = new_sdp;
+	i = sdp_str;
+
+
+	while(i && *i && i < end) {
+
+		if (*i == 'm' && *(i+1) == '=') {
+			in_m = 1;
+			m_tally++;
+		}
+
+		if (in_m) {
+			if (*i == '\r' || *i == '\n') {
+				in_m = 0;
+				slash = 0;
+			} else {
+				if (*i == '/') {
+					slash++;
+					while(*i != ' ' && i < end) {
+						*o++ = *i++;
+					}
+					
+					*o++ = *i++;
+				}
+					
+				if (slash && switch_is_leading_number(i)) {
+
+					
+					number = atoi(i);
+						
+					while(i < end && ((*i > 47 && *i < 58) || *i == ' ')) {
+
+						if (remove)  {
+							tst = (number != pt);
+						} else {
+							tst = (number == pt || number == te);
+						}
+
+						if (tst) {
+							*o++ = *i;
+						}
+						i++;
+							
+						if (*i == ' ') {
+							break;
+						}
+							
+					}
+
+					if (remove)  {
+						tst = (number == pt);
+					} else {
+						tst = (number != pt && number != te);
+					}
+
+					if (tst) {
+						skip++;
+					}
+				}
+			}
+		}
+
+		while (i < end && !strncasecmp(i, "a=rtpmap:", 9)) {
+			const char *t = i + 9;
+				
+			number = atoi(t);
+
+			if (remove)  {
+				tst = (number == pt);
+			} else {
+				tst = (number != pt && number != te);
+			}
+
+			while(i < end && (*i != '\r' && *i != '\n')) {
+				if (!tst) *o++ = *i;
+				i++;
+			}
+
+			while(i < end && (*i == '\r' || *i == '\n')) {
+				if (!tst) *o++ = *i;
+				i++;
+			}
+		}
+
+		while (i < end && !strncasecmp(i, "a=fmtp:", 7)) {
+			const char *t = i + 7;
+				
+			number = atoi(t);
+
+			if (remove)  {
+				tst = (number == pt);
+			} else {
+				tst = (number != pt && number != te);
+			}
+
+			while(i < end && (*i != '\r' && *i != '\n')) {
+				if (!tst) *o++ = *i;
+				i++;
+			}
+
+			while(i < end && (*i == '\r' || *i == '\n')) {
+				if (!tst) *o++ = *i;
+				i++;
+			}
+		}
+
+		if (!skip) {
+			*o++ = *i;
+		}
+
+		skip = 0;
+
+		i++;
+	}
+
+	*o = '\0';
+	
+	return new_sdp;
+}
+
+
 
 /* For Emacs:
  * Local Variables:

src/switch_core_session.c

@@ -654,7 +654,7 @@ SWITCH_DECLARE(switch_call_cause_t) switch_core_session_outgoing_channel(switch_
 			}
 
 			if ((val = switch_channel_get_variable(channel, SWITCH_R_SDP_VARIABLE))) {
-				switch_channel_set_variable(peer_channel, SWITCH_B_SDP_VARIABLE, val);
+				switch_channel_pass_sdp(channel, peer_channel, val);
 			}
 
 			if (switch_channel_test_flag(channel, CF_PROXY_MODE)) {

src/switch_utils.c

@@ -1231,6 +1231,25 @@ SWITCH_DECLARE(switch_bool_t) switch_is_number(const char *str)
 	return r;
 }
 
+SWITCH_DECLARE(switch_bool_t) switch_is_leading_number(const char *str)
+{
+	const char *p;
+	switch_bool_t r = SWITCH_FALSE;
+
+	if (*str == '-' || *str == '+') {
+		str++;
+	}
+
+	for (p = str; p && *p; p++) {
+		if ((*p == '.' || (*p > 47 && *p < 58))) {
+			r = SWITCH_TRUE;
+			break;
+		}
+	}
+
+	return r;
+}
+
 SWITCH_DECLARE(const char *) switch_stristr(const char *instr, const char *str)
 {
 /*