FS-6880 #resolve #comment I would think that in real life once the call agreed on a codec it would only offer the negotiated codecs but we can fix this to always filter for good measure. I am not sure what the ramifications are of filtering responses but I think this patch will do so as well.

src/include/switch_core_media.h

@@ -276,7 +276,7 @@ SWITCH_DECLARE(switch_rtp_crypto_key_type_t) switch_core_media_crypto_str2type(c
 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_DECLARE(char *) switch_core_media_process_sdp_filter(const char *sdp, const char *cmd_buf, switch_core_session_t *session);
 SWITCH_END_EXTERN_C
 #endif
 /* For Emacs:

src/mod/endpoints/mod_sofia/sofia.c

@@ -6348,6 +6348,7 @@ static void sofia_handle_sip_i_state(switch_core_session_t *session, int status,
 	int is_dup_sdp = 0;
 	switch_event_t *s_event = NULL;
 	char *p;
+	char *patched_sdp = NULL;
 
 	tl_gets(tags,
 			NUTAG_CALLSTATE_REF(ss_state),
@@ -6373,6 +6374,16 @@ static void sofia_handle_sip_i_state(switch_core_session_t *session, int status,
 		tech_pvt->mparams.last_sdp_str = NULL;
 	}
 
+	if (r_sdp && (switch_channel_test_flag(channel, CF_PROXY_MODE) || switch_channel_test_flag(channel, CF_PROXY_MEDIA))) {
+		const char *var;
+
+		if ((var = switch_channel_get_variable(channel, "bypass_media_sdp_filter"))) {
+			if ((patched_sdp = switch_core_media_process_sdp_filter(r_sdp, var, session))) {
+				r_sdp = patched_sdp;
+			}
+		}
+	}
+
 	if ((channel && (switch_channel_test_flag(channel, CF_PROXY_MODE) || switch_channel_test_flag(channel, CF_PROXY_MEDIA))) ||
 		(sofia_test_flag(profile, TFLAG_INB_NOMEDIA) || sofia_test_flag(profile, TFLAG_PROXY_MEDIA))) {
 
@@ -7319,6 +7330,7 @@ static void sofia_handle_sip_i_state(switch_core_session_t *session, int status,
 
   done:
 
+	switch_safe_free(patched_sdp);
 
 	if ((enum nua_callstate) ss_state == nua_callstate_ready && channel && session && tech_pvt) {
 		sofia_set_flag(tech_pvt, TFLAG_SIMPLIFY);

src/switch_channel.c

@@ -5222,57 +5222,21 @@ SWITCH_DECLARE(switch_status_t) switch_channel_unbind_device_state_handler(switc
 
 SWITCH_DECLARE(switch_status_t) switch_channel_pass_sdp(switch_channel_t *from_channel, switch_channel_t *to_channel, const char *sdp)
 {
+	switch_status_t status = SWITCH_STATUS_FALSE;
 	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);
+			if ((patched_sdp = switch_core_media_process_sdp_filter(use_sdp, var, from_channel->session))) {
-
+				use_sdp = patched_sdp;
-			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_channel_set_variable(to_channel, SWITCH_B_SDP_VARIABLE, use_sdp);
+		}
 	}
 
 	switch_safe_free(patched_sdp);

src/switch_core_media.c

@@ -9067,7 +9067,56 @@ SWITCH_DECLARE(char *) switch_core_media_filter_sdp(const char *sdp_str, const c
 	return new_sdp;
 }
 
+SWITCH_DECLARE(char *) switch_core_media_process_sdp_filter(const char *sdp, const char *cmd_buf, switch_core_session_t *session)
+{
+	switch_channel_t *channel = switch_core_session_get_channel(session);
+	char *cmd = switch_core_session_strdup(session, cmd_buf);
+	int argc = 0;
+	char *argv[50];
+	int x = 0;
+	char *use_sdp = (char *) sdp;
+	char *patched_sdp = NULL;
 
+	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(channel), SWITCH_LOG_WARNING, "%s SDP FILTER PARSE ERROR\n", switch_channel_get_name(channel));
+		} 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(channel), SWITCH_LOG_DEBUG, 
+							  "%s Filter command %s(%s)\nFROM:\n==========\n%s\nTO:\n==========\n%s\n\n", 
+							  switch_channel_get_name(channel),
+							  command, arg, patched_sdp ? patched_sdp : use_sdp, tmp_sdp);
+
+
+			if (tmp_sdp) {
+				switch_safe_free(patched_sdp);
+				patched_sdp = use_sdp = tmp_sdp;
+			}
+		}
+	}
+
+	return patched_sdp;
+
+}
 
 /* For Emacs:
  * Local Variables: