From 08cdc658cc054b2e07ffdd090e4d2b27ac53b567 Mon Sep 17 00:00:00 2001
From: Donat Zenichev <dzenichev@sipwise.com>
Date: Wed, 14 Aug 2024 11:57:06 +0200
Subject: [PATCH] MT#60693 add accepted legacy OSRTP for sdp_create()

Add support for accepted legacy OSRTP.
This must be used then in the sdp_create().

Change-Id: I627f88b844cc32e3884b3c6ae14e8a6977d0ce1c
---
 daemon/sdp.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/daemon/sdp.c b/daemon/sdp.c
index 6fb955cb5..6b952d1e1 100644
--- a/daemon/sdp.c
+++ b/daemon/sdp.c
@@ -3651,6 +3651,19 @@ static void sdp_out_add_media_connection(GString *out, struct call_media *media,
 			media_conn_address);
 }
 
+static void sdp_out_add_osrtp_media(GString *out, struct call_media *media,
+	const struct transport_protocol *prtp, unsigned int port)
+{
+	g_string_append_printf(out, "m=" STR_FORMAT " %d %s ",
+			STR_FMT(&media->type),
+			port,
+			prtp->name);
+
+	/* print codecs and add newline  */
+	print_codec_list(out, media);
+	g_string_append_printf(out, "\r\n");
+}
+
 /**
  * TODO: after sdp_replace() is deprecated, move the content of this func
  * to `print_sdp_media_section()`.
@@ -3683,6 +3696,7 @@ int sdp_create(str *out, struct call_monologue *monologue, sdp_ng_flags *flags)
 {
 	const char *err = NULL;
 	GString *s = NULL;
+	const struct transport_protocol *prtp = NULL;
 
 	err = "Need at least one media";
 	if (!monologue->medias->len)
@@ -3741,6 +3755,25 @@ int sdp_create(str *out, struct call_monologue *monologue, sdp_ng_flags *flags)
 		if (!rtp_ps->selected_sfd)
 			goto err;
 
+		prtp = NULL;
+		if (media->protocol && media->protocol->srtp)
+			prtp = &transport_protocols[media->protocol->rtp_proto];
+
+		if (prtp) {
+			if (MEDIA_ISSET(media, LEGACY_OSRTP) && !MEDIA_ISSET(media, LEGACY_OSRTP_REV))
+				/* generate rejected m= line for accepted legacy OSRTP */
+				sdp_out_add_osrtp_media(s, media, prtp, 0);
+			else if(flags->osrtp_offer_legacy && (flags->opmode == OP_OFFER || flags->opmode == OP_REQUEST)) {
+				const struct transport_protocol *proto = media->protocol;
+				media->protocol = prtp;
+
+				sdp_out_add_osrtp_media(s, media, prtp, rtp_ps->selected_sfd->socket.local.port);
+				handle_sdp_media_attributes(s, media, rtp_ps, rtp_ps_link, flags);
+
+				media->protocol = proto;
+			}
+		}
+
 		/* set: media type, port, protocol (e.g. RTP/SAVP) */
 		err = "Unknown media protocol";
 		if (media->protocol)
@@ -3761,6 +3794,10 @@ int sdp_create(str *out, struct call_monologue *monologue, sdp_ng_flags *flags)
 		g_string_append_printf(s, "\r\n");
 
 		handle_sdp_media_attributes(s, media, rtp_ps, rtp_ps_link, flags);
+
+		if (prtp && MEDIA_ISSET(media, LEGACY_OSRTP) && MEDIA_ISSET(media, LEGACY_OSRTP_REV))
+			/* generate rejected m= line for accepted legacy OSRTP */
+			sdp_out_add_osrtp_media(s, media, prtp, 0);
 	}
 
 	/* The SDP version gets increased in case: