feat: update current remote description with fingerprint

DOC.md

@@ -278,6 +278,24 @@ Return value: the length of the string copied in buffer (including the terminati
 
 If `buffer` is `NULL`, the description is not copied but the size is still returned.
 
+#### rtcGetCurrentRemoteDescription
+
+```
+int rtcGetCurrentRemoteDescription(int pc, char *buffer, int size)
+```
+
+Retrieves the currently negotiated remote description in SDP format.
+
+Arguments:
+
+- `pc`: the Peer Connection identifier
+- `buffer`: a user-supplied buffer to store the description
+- `size`: the size of `buffer`
+
+Return value: the length of the string copied in buffer (including the terminating null character) or a negative error code
+
+If `buffer` is `NULL`, the description is not copied but the size is still returned.
+
 #### rtcGetLocalDescriptionType
 
 ```

include/rtc/peerconnection.hpp

@@ -84,6 +84,7 @@ class RTC_CPP_EXPORT PeerConnection final : CheshireCat<impl::PeerConnection> {
  bool hasMedia() const;
  optional<Description> localDescription() const;
  optional<Description> remoteDescription() const;
+ optional<Description> currentRemoteDescription() const;
  size_t remoteMaxMessageSize() const;
  optional<string> localAddress() const;
  optional<string> remoteAddress() const;

include/rtc/rtc.h

@@ -216,6 +216,7 @@ RTC_C_EXPORT int rtcAddRemoteCandidate(int pc, const char *cand, const char *mid
 
 RTC_C_EXPORT int rtcGetLocalDescription(int pc, char *buffer, int size);
 RTC_C_EXPORT int rtcGetRemoteDescription(int pc, char *buffer, int size);
+RTC_C_EXPORT int rtcGetCurrentRemoteDescription(int pc, char *buffer, int size);
 
 RTC_C_EXPORT int rtcGetLocalDescriptionType(int pc, char *buffer, int size);
 RTC_C_EXPORT int rtcGetRemoteDescriptionType(int pc, char *buffer, int size);

src/capi.cpp

@@ -609,6 +609,17 @@ int rtcGetRemoteDescription(int pc, char *buffer, int size) {
  });
 }
 
+int rtcGetCurrentRemoteDescription(int pc, char *buffer, int size) {
+ return wrap([&] {
+ auto peerConnection = getPeerConnection(pc);
+
+ if (auto desc = peerConnection->currentRemoteDescription())
+ return copyAndReturn(string(*desc), buffer, size);
+ else
+ return RTC_ERR_NOT_AVAIL;
+ });
+}
+
 int rtcGetLocalDescriptionType(int pc, char *buffer, int size) {
  return wrap([&] {
  auto peerConnection = getPeerConnection(pc);

src/impl/peerconnection.cpp

@@ -118,6 +118,11 @@ optional<Description> PeerConnection::remoteDescription() const {
  return mRemoteDescription;
 }
 
+optional<Description> PeerConnection::currentRemoteDescription() const {
+ std::lock_guard lock(mCurrentRemoteDescriptionMutex);
+ return mCurrentRemoteDescription;
+}
+
 size_t PeerConnection::remoteMaxMessageSize() const {
  const size_t localMax = config.maxMessageSize.value_or(DEFAULT_LOCAL_MAX_MESSAGE_SIZE);
 
@@ -239,7 +244,7 @@ shared_ptr<DtlsTransport> PeerConnection::initDtlsTransport() {
  throw std::logic_error("No underlying ICE transport for DTLS transport");
 
  auto certificate = mCertificate.get();
- auto verifierCallback = weak_bind(&PeerConnection::checkFingerprint, this, _1);
+ auto verifierCallback = weak_bind(&PeerConnection::checkFingerprint, this, _1, fingerprintAlgorithm);
  auto dtlsStateChangeCallback =
  [this, weak_this = weak_from_this()](DtlsTransport::State transportState) {
  auto shared_this = weak_this.lock();
@@ -439,17 +444,21 @@ void PeerConnection::rollbackLocalDescription() {
  }
 }
 
-bool PeerConnection::checkFingerprint(const std::string &fingerprint) const {
+bool PeerConnection::checkFingerprint(const std::string &fingerprint, const CertificateFingerprint::Algorithm algorithm) {
  std::lock_guard lock(mRemoteDescriptionMutex);
  if (!mRemoteDescription || !mRemoteDescription->fingerprint())
  return false;
 
- if (config.disableFingerprintVerification)
- return true;
-
  auto expectedFingerprint = mRemoteDescription->fingerprint()->value;
- if (expectedFingerprint  == fingerprint) {
+ if (config.disableFingerprintVerification || expectedFingerprint == fingerprint) {
  PLOG_VERBOSE << "Valid fingerprint \"" << fingerprint << "\"";
+
+ if (mCurrentRemoteDescription) {
+ std::lock_guard lock(mCurrentRemoteDescriptionMutex);
+ // update current remote description with incoming fingerprint
+ mCurrentRemoteDescription->setFingerprint(CertificateFingerprint{algorithm, fingerprint});
+ }
+
  return true;
  }
 
@@ -1078,6 +1087,20 @@ void PeerConnection::processLocalCandidate(Candidate candidate) {
  &localCandidateCallback, std::move(candidate));
 }
 
+void PeerConnection::processCurrentRemoteDescription(Description description) {
+ {
+ // Set as current remote description
+ std::lock_guard lock(mCurrentRemoteDescriptionMutex);
+
+ std::vector<Candidate> existingCandidates;
+ if (mCurrentRemoteDescription)
+ existingCandidates = mCurrentRemoteDescription->extractCandidates();
+
+ mCurrentRemoteDescription.emplace(description);
+ mCurrentRemoteDescription->addCandidates(std::move(existingCandidates));
+ }
+}
+
 void PeerConnection::processRemoteDescription(Description description) {
  // Update the SSRC cache for existing tracks
  updateTrackSsrcCache(description);
@@ -1124,6 +1147,14 @@ void PeerConnection::processRemoteCandidate(Candidate candidate) {
  candidate.resolve(Candidate::ResolveMode::Simple);
  mRemoteDescription->addCandidate(candidate);
  }
+ {
+ // Set as remote candidate on current remote description too
+ std::lock_guard lock(mCurrentRemoteDescriptionMutex);
+ if (mCurrentRemoteDescription->hasCandidate(candidate))
+ return; // already in description, ignore
+
+ mCurrentRemoteDescription->addCandidate(candidate);
+ }
 
  if (candidate.isResolved()) {
  iceTransport->addRemoteCandidate(std::move(candidate));

src/impl/peerconnection.hpp

@@ -41,6 +41,7 @@ struct PeerConnection : std::enable_shared_from_this<PeerConnection> {
 
  optional<Description> localDescription() const;
  optional<Description> remoteDescription() const;
+ optional<Description> currentRemoteDescription() const;
  size_t remoteMaxMessageSize() const;
 
  shared_ptr<IceTransport> initIceTransport();
@@ -53,7 +54,7 @@ struct PeerConnection : std::enable_shared_from_this<PeerConnection> {
 
  void endLocalCandidates();
  void rollbackLocalDescription();
- bool checkFingerprint(const std::string &fingerprint) const;
+ bool checkFingerprint(const std::string &fingerprint, const CertificateFingerprint::Algorithm algorithm);
  void forwardMessage(message_ptr message);
  void forwardMedia(message_ptr message);
  void forwardBufferedAmount(uint16_t stream, size_t amount);
@@ -77,6 +78,7 @@ struct PeerConnection : std::enable_shared_from_this<PeerConnection> {
  void processLocalDescription(Description description);
  void processLocalCandidate(Candidate candidate);
  void processRemoteDescription(Description description);
+ void processCurrentRemoteDescription(Description description);
  void processRemoteCandidate(Candidate candidate);
  string localBundleMid() const;
 
@@ -135,8 +137,8 @@ struct PeerConnection : std::enable_shared_from_this<PeerConnection> {
 
  Processor mProcessor;
  optional<Description> mLocalDescription, mRemoteDescription;
- optional<Description> mCurrentLocalDescription;
- mutable std::mutex mLocalDescriptionMutex, mRemoteDescriptionMutex;
+ optional<Description> mCurrentLocalDescription, mCurrentRemoteDescription;
+ mutable std::mutex mLocalDescriptionMutex, mRemoteDescriptionMutex, mCurrentRemoteDescriptionMutex;
 
  shared_ptr<MediaHandler> mMediaHandler;
 

src/peerconnection.cpp

@@ -69,6 +69,10 @@ optional<Description> PeerConnection::remoteDescription() const {
  return impl()->remoteDescription();
 }
 
+optional<Description> PeerConnection::currentRemoteDescription() const {
+ return impl()->currentRemoteDescription();
+}
+
 size_t PeerConnection::remoteMaxMessageSize() const { return impl()->remoteMaxMessageSize(); }
 
 bool PeerConnection::hasMedia() const {
@@ -243,6 +247,7 @@ void PeerConnection::setRemoteDescription(Description description) {
  iceTransport->setRemoteDescription(description); // ICE transport might reject the description
 
  impl()->processRemoteDescription(std::move(description));
+ impl()->processCurrentRemoteDescription(std::move(description));
  impl()->changeSignalingState(newSignalingState);
  signalingLock.unlock();