sdp: Negotiate extmap-allow-mixed (#604)

haaspors · web-flow · commit 23bbc1fb7eb9 · 2024-08-18T05:27:07.000-07:00
This allows both one-byte and two-byte headers
diff --git a/sdp/src/description/media.rs b/sdp/src/description/media.rs
@@ -65,6 +65,11 @@ pub struct MediaDescription {
 }
 
 impl MediaDescription {
+    /// Returns whether an attribute exists
+    pub fn has_attribute(&self, key: &str) -> bool {
+        self.attributes.iter().any(|a| a.key == key)
+    }
+
     /// attribute returns the value of an attribute and if it exists
     pub fn attribute(&self, key: &str) -> Option<Option<&str>> {
         for a in &self.attributes {
diff --git a/sdp/src/description/session.rs b/sdp/src/description/session.rs
@@ -30,6 +30,7 @@ pub const ATTR_KEY_RECV_ONLY: &str = "recvonly";
 pub const ATTR_KEY_SEND_ONLY: &str = "sendonly";
 pub const ATTR_KEY_SEND_RECV: &str = "sendrecv";
 pub const ATTR_KEY_EXT_MAP: &str = "extmap";
+pub const ATTR_KEY_EXTMAP_ALLOW_MIXED: &str = "extmap-allow-mixed";
 
 /// Constants for semantic tokens used in JSEP
 pub const SEMANTIC_TOKEN_LIP_SYNCHRONIZATION: &str = "LS";
@@ -409,6 +410,11 @@ impl SessionDescription {
         Err(Error::CodecNotFound)
     }
 
+    /// Returns whether an attribute exists
+    pub fn has_attribute(&self, key: &str) -> bool {
+        self.attributes.iter().any(|a| a.key == key)
+    }
+
     /// Attribute returns the value of an attribute and if it exists
     pub fn attribute(&self, key: &str) -> Option<&String> {
         for a in &self.attributes {
diff --git a/webrtc/src/peer_connection/peer_connection_internal.rs b/webrtc/src/peer_connection/peer_connection_internal.rs
@@ -771,6 +771,7 @@ impl PeerConnectionInternal {
         let params = PopulateSdpParams {
             media_description_fingerprint: self.setting_engine.sdp_media_level_fingerprints,
             is_icelite: self.setting_engine.candidates.ice_lite,
+            extmap_allow_mixed: true,
             connection_role: DEFAULT_DTLS_ROLE_OFFER.to_connection_role(),
             ice_gathering_state: self.ice_gathering_state(),
             match_bundle_group: None,
@@ -804,8 +805,12 @@ impl PeerConnectionInternal {
         let remote_description = self.remote_description().await;
         let mut media_sections = vec![];
         let mut already_have_application_media_section = false;
+        let mut extmap_allow_mixed = false;
+
         if let Some(remote_description) = remote_description.as_ref() {
             if let Some(parsed) = &remote_description.parsed {
+                extmap_allow_mixed = parsed.has_attribute(ATTR_KEY_EXTMAP_ALLOW_MIXED);
+
                 for media in &parsed.media_descriptions {
                     if let Some(mid_value) = get_mid_value(media) {
                         if mid_value.is_empty() {
@@ -830,6 +835,8 @@ impl PeerConnectionInternal {
                             continue;
                         }
 
+                        let extmap_allow_mixed = media.has_attribute(ATTR_KEY_EXTMAP_ALLOW_MIXED);
+
                         if let Some(t) = find_by_mid(mid_value, &mut local_transceivers).await {
                             t.sender().await.set_negotiated();
                             let media_transceivers = vec![t];
@@ -843,6 +850,7 @@ impl PeerConnectionInternal {
                                 transceivers: media_transceivers,
                                 rid_map: get_rids(media),
                                 offered_direction: (!include_unmatched).then(|| direction),
+                                extmap_allow_mixed,
                                 ..Default::default()
                             });
                         } else {
@@ -896,6 +904,7 @@ impl PeerConnectionInternal {
         let params = PopulateSdpParams {
             media_description_fingerprint: self.setting_engine.sdp_media_level_fingerprints,
             is_icelite: self.setting_engine.candidates.ice_lite,
+            extmap_allow_mixed,
             connection_role,
             ice_gathering_state: self.ice_gathering_state(),
             match_bundle_group,
diff --git a/webrtc/src/peer_connection/sdp/mod.rs b/webrtc/src/peer_connection/sdp/mod.rs
@@ -462,6 +462,10 @@ pub(crate) async fn add_transceiver_sdp(
         .with_property_attribute(ATTR_KEY_RTCPMUX.to_owned())
         .with_property_attribute(ATTR_KEY_RTCPRSIZE.to_owned());
 
+    if media_section.extmap_allow_mixed {
+        media = media.with_property_attribute(ATTR_KEY_EXTMAP_ALLOW_MIXED.to_owned());
+    }
+
     let codecs = t.get_codecs().await;
     for codec in &codecs {
         let name = codec
@@ -772,11 +776,13 @@ pub(crate) struct MediaSection {
     pub(crate) data: bool,
     pub(crate) rid_map: Vec<SimulcastRid>,
     pub(crate) offered_direction: Option<RTCRtpTransceiverDirection>,
+    pub(crate) extmap_allow_mixed: bool,
 }
 
 pub(crate) struct PopulateSdpParams {
     pub(crate) media_description_fingerprint: bool,
     pub(crate) is_icelite: bool,
+    pub(crate) extmap_allow_mixed: bool,
     pub(crate) connection_role: ConnectionRole,
     pub(crate) ice_gathering_state: RTCIceGatheringState,
     pub(crate) match_bundle_group: Option<String>,
@@ -876,6 +882,11 @@ pub(crate) async fn populate_sdp(
         d = d.with_value_attribute(ATTR_KEY_GROUP.to_owned(), bundle_value);
     }
 
+    if params.extmap_allow_mixed {
+        // RFC 8285 6.
+        d = d.with_property_attribute(ATTR_KEY_EXTMAP_ALLOW_MIXED.to_owned());
+    }
+
     Ok(d)
 }
 
diff --git a/webrtc/src/peer_connection/sdp/sdp_test.rs b/webrtc/src/peer_connection/sdp/sdp_test.rs
@@ -581,6 +581,7 @@ async fn fingerprint_test(
     let params = PopulateSdpParams {
         media_description_fingerprint: sdpmedia_description_fingerprints,
         is_icelite: false,
+        extmap_allow_mixed: false,
         connection_role: ConnectionRole::Active,
         ice_gathering_state: RTCIceGatheringState::New,
         match_bundle_group: None,
@@ -777,6 +778,7 @@ async fn test_populate_sdp() -> Result<()> {
         let params = PopulateSdpParams {
             media_description_fingerprint: se.sdp_media_level_fingerprints,
             is_icelite: se.candidates.ice_lite,
+            extmap_allow_mixed: true,
             connection_role: DEFAULT_DTLS_ROLE_OFFER.to_connection_role(),
             ice_gathering_state: RTCIceGatheringState::Complete,
             match_bundle_group: None,
@@ -882,6 +884,7 @@ async fn test_populate_sdp() -> Result<()> {
         let params = PopulateSdpParams {
             media_description_fingerprint: se.sdp_media_level_fingerprints,
             is_icelite: se.candidates.ice_lite,
+            extmap_allow_mixed: true,
             connection_role: DEFAULT_DTLS_ROLE_OFFER.to_connection_role(),
             ice_gathering_state: RTCIceGatheringState::Complete,
             match_bundle_group: None,
@@ -962,6 +965,7 @@ async fn test_populate_sdp() -> Result<()> {
         let params = PopulateSdpParams {
             media_description_fingerprint: se.sdp_media_level_fingerprints,
             is_icelite: se.candidates.ice_lite,
+            extmap_allow_mixed: true,
             connection_role: DEFAULT_DTLS_ROLE_OFFER.to_connection_role(),
             ice_gathering_state: RTCIceGatheringState::Complete,
             match_bundle_group: None,
@@ -981,6 +985,8 @@ async fn test_populate_sdp() -> Result<()> {
             offer_sdp.attribute(ATTR_KEY_GROUP),
             Some(&"BUNDLE video".to_owned())
         );
+
+        assert!(offer_sdp.has_attribute(ATTR_KEY_EXTMAP_ALLOW_MIXED));
     }
 
     //"Bundle matched"
@@ -1057,6 +1063,7 @@ async fn test_populate_sdp() -> Result<()> {
         let params = PopulateSdpParams {
             media_description_fingerprint: se.sdp_media_level_fingerprints,
             is_icelite: se.candidates.ice_lite,
+            extmap_allow_mixed: true,
             connection_role: DEFAULT_DTLS_ROLE_OFFER.to_connection_role(),
             ice_gathering_state: RTCIceGatheringState::Complete,
             match_bundle_group: Some("audio".to_owned()),
@@ -1122,6 +1129,7 @@ async fn test_populate_sdp() -> Result<()> {
         let params = PopulateSdpParams {
             media_description_fingerprint: se.sdp_media_level_fingerprints,
             is_icelite: se.candidates.ice_lite,
+            extmap_allow_mixed: true,
             connection_role: DEFAULT_DTLS_ROLE_OFFER.to_connection_role(),
             ice_gathering_state: RTCIceGatheringState::Complete,
             match_bundle_group: Some("".to_owned()),
@@ -1231,6 +1239,7 @@ async fn test_populate_sdp_reject() -> Result<()> {
     let params = PopulateSdpParams {
         media_description_fingerprint: se.sdp_media_level_fingerprints,
         is_icelite: se.candidates.ice_lite,
+        extmap_allow_mixed: true,
         connection_role: DEFAULT_DTLS_ROLE_OFFER.to_connection_role(),
         ice_gathering_state: RTCIceGatheringState::Complete,
         match_bundle_group: None,
