WIP: Implement XEP-0320: Use of DTLS-SRTP in Jingle Sessions

src/base/QXmppConstants.cpp

@@ -135,6 +135,8 @@ const char* ns_message_correct = "urn:xmpp:message-correct:0";
 const char* ns_mam = "urn:xmpp:mam:2";
 // XEP-0319: Last User Interaction in Presence
 const char* ns_idle = "urn:xmpp:idle:1";
+// XEP-0320: Use of DTLS-SRTP in Jingle Sessions
+const char* ns_jingle_dtls = "urn:xmpp:jingle:apps:dtls:0";
 // XEP-0333: Chat Markers
 const char* ns_chat_markers = "urn:xmpp:chat-markers:0";
 // XEP-0334: Message Processing Hints

src/base/QXmppConstants_p.h

@@ -147,6 +147,8 @@ extern const char* ns_message_correct;
 extern const char* ns_mam;
 // XEP-0319: Last User Interaction in Presence
 extern const char* ns_idle;
+// XEP-0320: Use of DTLS-SRTP in Jingle Sessions
+extern const char* ns_jingle_dtls;
 // XEP-0333: Char Markers
 extern const char* ns_chat_markers;
 // XEP-0334: Message Processing Hints:

src/base/QXmppJingleIq.cpp

@@ -34,7 +34,6 @@
 static const int RTP_COMPONENT = 1;
 
 static const char *ns_jingle_rtp_info = "urn:xmpp:jingle:apps:rtp:info:1";
-static const char *ns_jingle_dtls = "urn:xmpp:jingle:apps:dtls:0";
 
 static const char *jingle_actions[] = {
     "content-accept",

src/client/QXmppCall.cpp

@@ -113,18 +113,9 @@ void QXmppCallPrivate::padAdded(GstPad *pad)
     if (nameParts.size() < 4) {
         return;
     }
-    if (nameParts[0] == QLatin1String("send") &&
-        nameParts[1] == QLatin1String("rtp") &&
+    if (nameParts[0] == QLatin1String("recv") ||
+        nameParts[1] == QLatin1String("rtp") ||
         nameParts[2] == QLatin1String("src")) {
-        if (nameParts.size() != 4) {
-            return;
-        }
-        int sessionId = nameParts[3].toInt();
-        auto stream = findStreamById(sessionId);
-        stream->d->addRtpSender(pad);
-    } else if (nameParts[0] == QLatin1String("recv") ||
-               nameParts[1] == QLatin1String("rtp") ||
-               nameParts[2] == QLatin1String("src")) {
         if (nameParts.size() != 6) {
             return;
         }
@@ -331,6 +322,10 @@ void QXmppCallPrivate::handleRequest(const QXmppJingleIq &iq)
             return;
         }
 
+        if (useDtls && content.transportFingerprintSetup() == QLatin1String("passive")) {
+            stream->d->toDtlsClientMode();
+        }
+
         // check for call establishment
         setState(QXmppCall::ActiveState);
 
@@ -401,7 +396,8 @@ void QXmppCallPrivate::handleRequest(const QXmppJingleIq &iq)
         iq.setType(QXmppIq::Set);
         iq.setAction(QXmppJingleIq::ContentAccept);
         iq.setSid(q->sid());
-        iq.addContent(localContent(stream));
+        iq.addContent(localContent(stream, QLatin1String("active")));
+        stream->d->toDtlsClientMode();
         sendRequest(iq);
 
     } else if (iq.action() == QXmppJingleIq::TransportInfo) {
@@ -435,7 +431,7 @@ QXmppCallStream *QXmppCallPrivate::createStream(const QString &media, const QStr
         return nullptr;
     }
 
-    QXmppCallStream *stream = new QXmppCallStream(pipeline, rtpbin, media, creator, name, ++nextId);
+    QXmppCallStream *stream = new QXmppCallStream(pipeline, rtpbin, media, creator, name, ++nextId, useDtls);
 
     // Fill local payload payload types
     auto &codecs = media == AUDIO_MEDIA ? audioCodecs : videoCodecs;
@@ -470,7 +466,7 @@ QXmppCallStream *QXmppCallPrivate::createStream(const QString &media, const QStr
     return stream;
 }
 
-QXmppJingleIq::Content QXmppCallPrivate::localContent(QXmppCallStream *stream) const
+QXmppJingleIq::Content QXmppCallPrivate::localContent(QXmppCallStream *stream, QString dtlsSetup) const
 {
     QXmppJingleIq::Content content;
     content.setCreator(stream->creator());
@@ -487,6 +483,13 @@ QXmppJingleIq::Content QXmppCallPrivate::localContent(QXmppCallStream *stream) c
     content.setTransportPassword(stream->d->connection->localPassword());
     content.setTransportCandidates(stream->d->connection->localCandidates());
 
+    // encryption
+    if (useDtls) {
+        content.setTransportFingerprint(stream->d->digest);
+        content.setTransportFingerprintHash("sha-256");
+        content.setTransportFingerprintSetup(dtlsSetup);
+    }
+
     return content;
 }
 
@@ -514,7 +517,7 @@ bool QXmppCallPrivate::sendInvite()
     iq.setAction(QXmppJingleIq::SessionInitiate);
     iq.setInitiator(ownJid);
     iq.setSid(sid);
-    iq.addContent(localContent(stream));
+    iq.addContent(localContent(stream, QLatin1String("actpass")));
     return sendRequest(iq);
 }
 
@@ -562,13 +565,14 @@ void QXmppCallPrivate::terminate(QXmppJingleIq::Reason::Type reasonType)
     QTimer::singleShot(5000, q, SLOT(terminated()));
 }
 
-QXmppCall::QXmppCall(const QString &jid, QXmppCall::Direction direction, QXmppCallManager *parent)
+QXmppCall::QXmppCall(const QString &jid, QXmppCall::Direction direction, bool useDtls, QXmppCallManager *parent)
     : QXmppLoggable(parent)
 {
     d = new QXmppCallPrivate(this);
     d->direction = direction;
     d->jid = jid;
     d->ownJid = parent->client()->configuration().jid();
+    d->useDtls = true;
     d->manager = parent;
 }
 
@@ -593,7 +597,8 @@ void QXmppCall::accept()
         iq.setAction(QXmppJingleIq::SessionAccept);
         iq.setResponder(d->ownJid);
         iq.setSid(d->sid);
-        iq.addContent(d->localContent(stream));
+        iq.addContent(d->localContent(stream, QLatin1String("active")));
+        stream->d->toDtlsClientMode();
         d->sendRequest(iq);
 
         // notify user
@@ -680,7 +685,7 @@ void QXmppCall::localCandidatesChanged()
     iq.setType(QXmppIq::Set);
     iq.setAction(QXmppJingleIq::TransportInfo);
     iq.setSid(d->sid);
-    iq.addContent(d->localContent(stream));
+    iq.addContent(d->localContent(stream, QLatin1String()));
     d->sendRequest(iq);
 }
 
@@ -734,6 +739,13 @@ void QXmppCall::addVideo()
     iq.setType(QXmppIq::Set);
     iq.setAction(QXmppJingleIq::ContentAdd);
     iq.setSid(d->sid);
-    iq.addContent(d->localContent(stream));
+    iq.addContent(d->localContent(stream, QLatin1String("actpass")));
     d->sendRequest(iq);
 }
+
+// Returns if the call is encrypted
+
+bool QXmppCall::isEncrypted() const
+{
+    return d->useDtls;
+}

src/client/QXmppCall.h

@@ -75,6 +75,8 @@ class QXMPP_EXPORT QXmppCall : public QXmppLoggable
     QXmppCallStream *audioStream() const;
     QXmppCallStream *videoStream() const;
 
+    bool isEncrypted() const;
+
 signals:
     /// \brief This signal is emitted when a call is connected.
     ///
@@ -108,7 +110,7 @@ private slots:
     void terminated();
 
 private:
-    QXmppCall(const QString &jid, QXmppCall::Direction direction, QXmppCallManager *parent);
+    QXmppCall(const QString &jid, QXmppCall::Direction direction, bool useDtls, QXmppCallManager *parent);
 
     QXmppCallPrivate *d;
     friend class QXmppCallManager;

src/client/QXmppCallManager.cpp

@@ -29,6 +29,7 @@
 #include "QXmppClient.h"
 #include "QXmppConstants_p.h"
 #include "QXmppJingleIq.h"
+#include "QXmppRosterManager.h"
 #include "QXmppStun.h"
 #include "QXmppUtils.h"
 
@@ -43,6 +44,21 @@ QXmppCallManagerPrivate::QXmppCallManagerPrivate(QXmppCallManager *qq)
 {
     // Initialize GStreamer
     gst_init(nullptr, nullptr);
+
+    supportsDtls = true;
+    GstElementFactory *factory;
+    factory = gst_element_factory_find("dtlssrtpenc");
+    if (!factory) {
+        supportsDtls = false;
+    } else {
+        g_object_unref(factory);
+    }
+    factory = gst_element_factory_find("dtlssrtpdec");
+    if (!factory) {
+        supportsDtls = false;
+    } else {
+        g_object_unref(factory);
+    }
 }
 
 QXmppCall *QXmppCallManagerPrivate::findCall(const QString &sid) const
@@ -80,12 +96,17 @@ QXmppCallManager::~QXmppCallManager()
 /// \cond
 QStringList QXmppCallManager::discoveryFeatures() const
 {
-    return QStringList()
+    QStringList features;
+    features
         << ns_jingle      // XEP-0166 : Jingle
         << ns_jingle_rtp  // XEP-0167 : Jingle RTP Sessions
         << ns_jingle_rtp_audio
         << ns_jingle_rtp_video
         << ns_jingle_ice_udp;  // XEP-0176 : Jingle ICE-UDP Transport Method
+    if (d->supportsDtls) {
+        features << ns_jingle_dtls;  // XEP-0320: Use of DTLS-SRTP in Jingle Sessions
+    }
+    return features;
 }
 
 bool QXmppCallManager::handleStanza(const QDomElement &element)
@@ -136,7 +157,12 @@ QXmppCall *QXmppCallManager::call(const QString &jid)
         return nullptr;
     }
 
-    QXmppCall *call = new QXmppCall(jid, QXmppCall::OutgoingDirection, this);
+    /* Determine support for XEP-0320: Use of DTLS-SRTP in Jingle Sessions */
+    QXmppRosterManager *rosterManager = client()->findExtension<QXmppRosterManager>();
+    QXmppPresence presence = rosterManager->getPresence(QXmppUtils::jidToBareJid(jid), QXmppUtils::jidToResource(jid));
+    bool remoteSupportsDtls = presence.capabilityExt().contains(ns_jingle_dtls);
+
+    QXmppCall *call = new QXmppCall(jid, QXmppCall::OutgoingDirection, remoteSupportsDtls && d->supportsDtls, this);
     QXmppCallStream *stream = call->d->createStream("audio", "initiator", "microphone");
     call->d->streams << stream;
     call->d->sid = QXmppUtils::generateStanzaHash();
@@ -247,14 +273,23 @@ void QXmppCallManager::_q_jingleIqReceived(const QXmppJingleIq &iq)
         return;
 
     if (iq.action() == QXmppJingleIq::SessionInitiate) {
+        const QXmppJingleIq::Content content = iq.contents().isEmpty() ? QXmppJingleIq::Content() : iq.contents().first();
+
         // build call
-        QXmppCall *call = new QXmppCall(iq.from(), QXmppCall::IncomingDirection, this);
+        bool useDtls = !content.transportFingerprint().isEmpty();
+        QXmppCall *call = new QXmppCall(iq.from(), QXmppCall::IncomingDirection, useDtls, this);
         call->d->sid = iq.sid();
 
-        const QXmppJingleIq::Content content = iq.contents().isEmpty() ? QXmppJingleIq::Content() : iq.contents().first();
+        if (useDtls && !d->supportsDtls) {
+            call->d->terminate(QXmppJingleIq::Reason::FailedApplication);
+            return;
+        }
+
         QXmppCallStream *stream = call->d->createStream(content.descriptionMedia(), content.creator(), content.name());
-        if (!stream)
+        if (!stream) {
+            call->d->terminate(QXmppJingleIq::Reason::FailedApplication);
             return;
+        }
         call->d->streams << stream;
 
         // send ack

src/client/QXmppCallManager_p.h

@@ -55,6 +55,8 @@ class QXmppCallManagerPrivate
     QString turnUser;
     QString turnPassword;
 
+    bool supportsDtls;
+
 private:
     QXmppCallManager *q;
 };