From 95b814553b44c7eda165f17f462dd986cc8c438f Mon Sep 17 00:00:00 2001
From: Richard Fuchs <rfuchs@sipwise.com>
Date: Mon, 28 Sep 2020 13:13:11 -0400
Subject: [PATCH] TT#94201 add ICE=default option

Change-Id: If10e0aa284cc7cc5c1e69855733835bd5b52da31
---
 README.md                 | 22 +++++++++++++++-------
 daemon/call.c             |  7 ++++++-
 daemon/call_interfaces.c  |  5 +++++
 include/call_interfaces.h |  1 +
 4 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index ac5b59f45..9d00aed29 100644
--- a/README.md
+++ b/README.md
@@ -873,18 +873,26 @@ Optionally included keys are:
 
 * `ICE`
 
-	Contains a string, valid values are `remove`, `force` or `force-relay`.
-	With `remove`, any ICE attributes are
-	stripped from the SDP body. With `force`, ICE attributes are first stripped, then new attributes are
-	generated and inserted, which leaves the media proxy as the only ICE candidate. The default behavior
-	(no `ICE` key present at all) is: if no ICE attributes are present, a new set is generated and the
-	media proxy lists itself as ICE candidate; otherwise, the media proxy inserts itself as a
-	low-priority candidate.
+	Contains a string which must be one of the following values:
+
+	With `remove`, any ICE attributes are stripped from the SDP body.
+
+	With `force`, ICE attributes are first stripped, then new attributes are
+	generated and inserted, which leaves the media proxy as the only ICE candidate.
+
+	With `default`, the behaviour will be the same as with `force` if the incoming SDP already
+	had ICE attributes listed. If the incoming SDP did not contain ICE attributes, then no
+	ICE attributes are added.
 
 	With `force-relay`, existing ICE candidates are left in place except `relay`
 	type candidates, and *rtpengine* inserts itself as a `relay` candidate. It will also leave SDP
 	c= and m= lines unchanged.
 
+	The default behavior
+	(no `ICE` key present at all) is: if no ICE attributes are present, a new set is generated and the
+	media proxy lists itself as ICE candidate; otherwise, the media proxy inserts itself as a
+	low-priority candidate.
+
 	This flag operates independently of the `replace` flags.
 
 * `transport protocol`
diff --git a/daemon/call.c b/daemon/call.c
index d304851ee..11ac032b8 100644
--- a/daemon/call.c
+++ b/daemon/call.c
@@ -1242,7 +1242,12 @@ static void __ice_offer(const struct sdp_ng_flags *flags, struct call_media *thi
 	/* we offer ICE by default */
 	if (!MEDIA_ISSET(this, INITIALIZED))
 		MEDIA_SET(this, ICE);
-	if (flags->ice_remove)
+	// unless instructed not to
+	if (flags->ice_default) {
+		if (!MEDIA_ISSET(other, ICE))
+			MEDIA_CLEAR(this, ICE);
+	}
+	else if (flags->ice_remove)
 		MEDIA_CLEAR(this, ICE);
 
 	if (flags->passthrough_on) {
diff --git a/daemon/call_interfaces.c b/daemon/call_interfaces.c
index 7592708c6..19d0d7924 100644
--- a/daemon/call_interfaces.c
+++ b/daemon/call_interfaces.c
@@ -932,6 +932,11 @@ static void call_ng_process_flags(struct sdp_ng_flags *out, bencode_item_t *inpu
 			case CSH_LOOKUP("force"):
 				out->ice_force = 1;
 				break;
+			case CSH_LOOKUP("default"):
+				out->ice_default = 1;
+				out->ice_force = 1;
+				out->ice_remove = 1;
+				break;
 			case CSH_LOOKUP("force_relay"):
 			case CSH_LOOKUP("force-relay"):
 			case CSH_LOOKUP("force relay"):
diff --git a/include/call_interfaces.h b/include/call_interfaces.h
index 4e43dc58f..587fb959b 100644
--- a/include/call_interfaces.h
+++ b/include/call_interfaces.h
@@ -58,6 +58,7 @@ struct sdp_ng_flags {
 	    ice_remove:1,
 	    ice_force:1,
 	    ice_force_relay:1,
+	    ice_default:1,
 	    rtcp_mux_offer:1,
 	    rtcp_mux_require:1,
 	    rtcp_mux_demux:1,