Add initial support for DTLS-SRTP

5 files changed, 716 insertions, 6 deletions

diff --git a/plugins/ice/CMakeLists.txt b/plugins/ice/CMakeLists.txt
index 90fe5b7d..38025aa0 100644
--- a/plugins/ice/CMakeLists.txt
+++ b/plugins/ice/CMakeLists.txt
@@ -2,6 +2,7 @@ find_packages(ICE_PACKAGES REQUIRED
     Gee
     GLib
     GModule
+    GnuTLS
     GObject
     GTK3
     Nice
@@ -9,8 +10,9 @@ find_packages(ICE_PACKAGES REQUIRED
 
 vala_precompile(ICE_VALA_C
 SOURCES
-    src/plugin.vala
+    src/dtls_srtp.vala
     src/module.vala
+    src/plugin.vala
     src/transport_parameters.vala
     src/util.vala
     src/register_plugin.vala
@@ -18,6 +20,7 @@ CUSTOM_VAPIS
     ${CMAKE_BINARY_DIR}/exports/xmpp-vala.vapi
     ${CMAKE_BINARY_DIR}/exports/dino.vapi
     ${CMAKE_BINARY_DIR}/exports/qlite.vapi
+    ${CMAKE_BINARY_DIR}/exports/crypto.vapi
 PACKAGES
     ${ICE_PACKAGES}
 OPTIONS
@@ -26,7 +29,7 @@ OPTIONS
 
 add_definitions(${VALA_CFLAGS} -DG_LOG_DOMAIN="ice")
 add_library(ice SHARED ${ICE_VALA_C})
-target_link_libraries(ice libdino ${ICE_PACKAGES})
+target_link_libraries(ice libdino crypto-vala ${ICE_PACKAGES})
 set_target_properties(ice PROPERTIES PREFIX "")
 set_target_properties(ice PROPERTIES LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/plugins/)
 
diff --git a/plugins/ice/src/dtls_srtp.vala b/plugins/ice/src/dtls_srtp.vala
new file mode 100644
index 00000000..a21c242b
--- /dev/null
+++ b/plugins/ice/src/dtls_srtp.vala
@@ -0,0 +1,247 @@
+using GnuTLS;
+
+public class DtlsSrtp {
+
+    public signal void send_data(uint8[] data);
+
+    private X509.Certificate[] own_cert;
+    private X509.PrivateKey private_key;
+    private Cond buffer_cond = new Cond();
+    private Mutex buffer_mutex = new Mutex();
+    private Gee.LinkedList<Bytes> buffer_queue = new Gee.LinkedList<Bytes>();
+    private uint pull_timeout = uint.MAX;
+    private string peer_fingerprint;
+
+    private Crypto.Srtp.Session encrypt_session;
+    private Crypto.Srtp.Session decrypt_session;
+
+    public static DtlsSrtp setup() throws GLib.Error {
+        var obj = new DtlsSrtp();
+        obj.generate_credentials();
+        return obj;
+    }
+
+    internal string get_own_fingerprint(DigestAlgorithm digest_algo) {
+        return format_certificate(own_cert[0], digest_algo);
+    }
+
+    public void set_peer_fingerprint(string fingerprint) {
+        this.peer_fingerprint = fingerprint;
+    }
+
+    public uint8[] process_incoming_data(uint component_id, uint8[] data) {
+        if (decrypt_session != null) {
+            if (component_id == 1) return decrypt_session.decrypt_rtp(data);
+            if (component_id == 2) return decrypt_session.decrypt_rtcp(data);
+        } else if (component_id == 1) {
+            on_data_rec(data);
+        }
+        return null;
+    }
+
+    public uint8[] process_outgoing_data(uint component_id, uint8[] data) {
+        if (encrypt_session != null) {
+            if (component_id == 1) return encrypt_session.encrypt_rtp(data);
+            if (component_id == 2) return encrypt_session.encrypt_rtcp(data);
+        }
+        return null;
+    }
+
+    public void on_data_rec(owned uint8[] data) {
+        buffer_mutex.lock();
+        buffer_queue.add(new Bytes.take(data));
+        buffer_cond.signal();
+        buffer_mutex.unlock();
+    }
+
+    private void generate_credentials() throws GLib.Error {
+        int err = 0;
+
+        private_key = X509.PrivateKey.create();
+        err = private_key.generate(PKAlgorithm.RSA, 2048);
+        throw_if_error(err);
+
+        var start_time = new DateTime.now_local().add_days(1);
+        var end_time = start_time.add_days(2);
+
+        X509.Certificate cert = X509.Certificate.create();
+        cert.set_key(private_key);
+        cert.set_version(1);
+        cert.set_activation_time ((time_t) start_time.to_unix ());
+        cert.set_expiration_time ((time_t) end_time.to_unix ());
+
+        uint32 serial = 1;
+        cert.set_serial(&serial, sizeof(uint32));
+
+        cert.sign(cert, private_key);
+
+        own_cert = new X509.Certificate[] { (owned)cert };
+    }
+
+    public async void setup_dtls_connection(bool server) {
+        InitFlags server_or_client = server ? InitFlags.SERVER : InitFlags.CLIENT;
+        debug("Setting up DTLS connection. We're %s", server_or_client.to_string());
+
+        CertificateCredentials cert_cred = CertificateCredentials.create();
+        int err = cert_cred.set_x509_key(own_cert, private_key);
+        throw_if_error(err);
+
+        Session? session = Session.create(server_or_client | InitFlags.DATAGRAM);
+        session.enable_heartbeat(1);
+        session.set_srtp_profile_direct("SRTP_AES128_CM_HMAC_SHA1_80");
+        session.set_credentials(GnuTLS.CredentialsType.CERTIFICATE, cert_cred);
+        session.server_set_request(CertificateRequest.REQUEST);
+        session.set_priority_from_string("NORMAL:!VERS-TLS-ALL:+VERS-DTLS-ALL:+CTYPE-CLI-X509");
+
+        session.set_transport_pointer(this);
+        session.set_pull_function(pull_function);
+        session.set_pull_timeout_function(pull_timeout_function);
+        session.set_push_function(push_function);
+        session.set_verify_function(verify_function);
+
+        Thread<int> thread = new Thread<int> (null, () => {
+            DateTime maximum_time = new DateTime.now_utc().add_seconds(20);
+            do {
+                err = session.handshake();
+
+                DateTime current_time = new DateTime.now_utc();
+                if (maximum_time.compare(current_time) < 0) {
+                    warning("DTLS handshake timeouted");
+                    return -1;
+                }
+            } while (err < 0 && !((ErrorCode)err).is_fatal());
+            Idle.add(setup_dtls_connection.callback);
+            return err;
+        });
+        yield;
+        err = thread.join();
+
+        uint8[] km = new uint8[150];
+        Datum? client_key, client_salt, server_key, server_salt;
+        session.get_srtp_keys(km, km.length, out client_key, out client_salt, out server_key, out server_salt);
+        if (client_key == null || client_salt == null || server_key == null || server_salt == null) {
+            warning("SRTP client/server key/salt null");
+        }
+
+        Crypto.Srtp.Session encrypt_session = new Crypto.Srtp.Session(Crypto.Srtp.Encryption.AES_CM, Crypto.Srtp.Authentication.HMAC_SHA1, 10, Crypto.Srtp.Prf.AES_CM, 0);
+        Crypto.Srtp.Session decrypt_session = new Crypto.Srtp.Session(Crypto.Srtp.Encryption.AES_CM, Crypto.Srtp.Authentication.HMAC_SHA1, 10, Crypto.Srtp.Prf.AES_CM, 0);
+
+        if (server) {
+            encrypt_session.setkey(server_key.extract(), server_salt.extract());
+            decrypt_session.setkey(client_key.extract(), client_salt.extract());
+        } else {
+            encrypt_session.setkey(client_key.extract(), client_salt.extract());
+            decrypt_session.setkey(server_key.extract(), server_salt.extract());
+        }
+
+        this.encrypt_session = (owned)encrypt_session;
+        this.decrypt_session = (owned)decrypt_session;
+    }
+
+    private static ssize_t pull_function(void* transport_ptr, uint8[] buffer) {
+        DtlsSrtp self = transport_ptr as DtlsSrtp;
+
+        self.buffer_mutex.lock();
+        while (self.buffer_queue.size == 0) {
+            self.buffer_cond.wait(self.buffer_mutex);
+        }
+        owned Bytes data = self.buffer_queue.remove_at(0);
+        self.buffer_mutex.unlock();
+
+        uint8[] data_uint8 = Bytes.unref_to_data(data);
+        Memory.copy(buffer, data_uint8, data_uint8.length);
+
+        // The callback should return 0 on connection termination, a positive number indicating the number of bytes received, and -1 on error.
+        return (ssize_t)data.length;
+    }
+
+    private static int pull_timeout_function(void* transport_ptr, uint ms) {
+        DtlsSrtp self = transport_ptr as DtlsSrtp;
+
+        DateTime current_time = new DateTime.now_utc();
+        current_time.add_seconds(ms/1000);
+        int64 end_time = current_time.to_unix();
+
+        self.buffer_mutex.lock();
+        while (self.buffer_queue.size == 0) {
+            self.buffer_cond.wait_until(self.buffer_mutex, end_time);
+
+            DateTime new_current_time = new DateTime.now_utc();
+            if (new_current_time.compare(current_time) > 0) {
+                break;
+            }
+        }
+        self.buffer_mutex.unlock();
+
+        // The callback should return 0 on timeout, a positive number if data can be received, and -1 on error.
+        return 1;
+    }
+
+    private static ssize_t push_function(void* transport_ptr, uint8[] buffer) {
+        DtlsSrtp self = transport_ptr as DtlsSrtp;
+        self.send_data(buffer);
+
+        // The callback should return a positive number indicating the bytes sent, and -1 on error.
+        return (ssize_t)buffer.length;
+    }
+
+    private static int verify_function(Session session) {
+        DtlsSrtp self = session.get_transport_pointer() as DtlsSrtp;
+        try {
+            bool valid = self.verify_peer_cert(session);
+            if (!valid) {
+                warning("DTLS certificate invalid. Aborting handshake.");
+                return 1;
+            }
+        } catch (Error e) {
+            warning("Error during DTLS certificate validation: %s. Aborting handshake.", e.message);
+            return 1;
+        }
+
+        // The callback function should return 0 for the handshake to continue or non-zero to terminate.
+        return 0;
+    }
+
+    private bool verify_peer_cert(Session session) throws GLib.Error {
+        unowned Datum[] cert_datums = session.get_peer_certificates();
+        if (cert_datums.length == 0) {
+            warning("No peer certs");
+            return false;
+        }
+        if (cert_datums.length > 1) warning("More than one peer cert");
+
+        X509.Certificate peer_cert = X509.Certificate.create();
+        peer_cert.import(ref cert_datums[0], CertificateFormat.DER);
+
+        string peer_fp_str = format_certificate(peer_cert, DigestAlgorithm.SHA256);
+        if (peer_fp_str.down() != this.peer_fingerprint.down()) {
+            warning("First cert in peer cert list doesn't equal advertised one %s vs %s", peer_fp_str, this.peer_fingerprint);
+            return false;
+        }
+
+        return true;
+    }
+
+    private string format_certificate(X509.Certificate certificate, DigestAlgorithm digest_algo) {
+        uint8[] buf = new uint8[512];
+        size_t buf_out_size = 512;
+        certificate.get_fingerprint(digest_algo, buf, ref buf_out_size);
+
+        var sb = new StringBuilder();
+        for (int i = 0; i < buf_out_size; i++) {
+            sb.append("%02x".printf(buf[i]));
+            if (i < buf_out_size - 1) {
+                sb.append(":");
+            }
+        }
+        return sb.str;
+    }
+
+    private uint8[] uint8_pt_to_a(uint8* data, uint size) {
+        uint8[size] ret = new uint8[size];
+        for (int i = 0; i < size; i++) {
+            ret[i] = data[i];
+        }
+        return ret;
+    }
+}
\ No newline at end of file
diff --git a/plugins/ice/src/transport_parameters.vala b/plugins/ice/src/transport_parameters.vala
index a8172678..5b6431c2 100644
--- a/plugins/ice/src/transport_parameters.vala
+++ b/plugins/ice/src/transport_parameters.vala
@@ -9,9 +9,11 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
     private bool we_want_connection;
     private bool remote_credentials_set;
     private Map<uint8, DatagramConnection> connections = new HashMap<uint8, DatagramConnection>();
+    private DtlsSrtp? dtls_srtp;
 
     private class DatagramConnection : Jingle.DatagramConnection {
         private Nice.Agent agent;
+        private DtlsSrtp? dtls_srtp;
         private uint stream_id;
         private string? error;
         private ulong sent;
@@ -20,8 +22,9 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
         private ulong recv_reported;
         private ulong datagram_received_id;
 
-        public DatagramConnection(Nice.Agent agent, uint stream_id, uint8 component_id) {
+        public DatagramConnection(Nice.Agent agent, DtlsSrtp? dtls_srtp, uint stream_id, uint8 component_id) {
             this.agent = agent;
+            this.dtls_srtp = dtls_srtp;
             this.stream_id = stream_id;
             this.component_id = component_id;
             this.datagram_received_id = this.datagram_received.connect((datagram) => {
@@ -41,7 +44,12 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
 
         public override void send_datagram(Bytes datagram) {
             if (this.agent != null && is_component_ready(agent, stream_id, component_id)) {
-                agent.send(stream_id, component_id, datagram.get_data());
+                uint8[] encrypted_data = null;
+                if (dtls_srtp != null) {
+                    encrypted_data = dtls_srtp.process_outgoing_data(component_id, datagram.get_data());
+                    if (encrypted_data == null) return;
+                }
+                agent.send(stream_id, component_id, encrypted_data ?? datagram.get_data());
                 sent += datagram.length;
                 if (sent > sent_reported + 100000) {
                     debug("Sent %lu bytes via stream %u component %u", sent, stream_id, component_id);
@@ -55,6 +63,20 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
         base(components, local_full_jid, peer_full_jid, node);
         this.we_want_connection = (node == null);
         this.agent = agent;
+
+        if (this.peer_fingerprint != null || !incoming) {
+            dtls_srtp = DtlsSrtp.setup();
+            dtls_srtp.send_data.connect((data) => {
+                agent.send(stream_id, 1, data);
+            });
+            this.own_fingerprint = dtls_srtp.get_own_fingerprint(GnuTLS.DigestAlgorithm.SHA256);
+            if (incoming) {
+                dtls_srtp.set_peer_fingerprint(this.peer_fingerprint);
+            } else {
+                dtls_srtp.setup_dtls_connection(true);
+            }
+        }
+
         agent.candidate_gathering_done.connect(on_candidate_gathering_done);
         agent.initial_binding_request_received.connect(on_initial_binding_request_received);
         agent.component_state_changed.connect(on_component_state_changed);
@@ -112,6 +134,12 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
     public override void handle_transport_accept(StanzaNode transport) throws Jingle.IqError {
         debug("on_transport_accept from %s", peer_full_jid.to_string());
         base.handle_transport_accept(transport);
+
+        if (dtls_srtp != null && peer_fingerprint != null) {
+            dtls_srtp.set_peer_fingerprint(this.peer_fingerprint);
+        } else {
+            dtls_srtp = null;
+        }
     }
 
     public override void handle_transport_info(StanzaNode transport) throws Jingle.IqError {
@@ -163,9 +191,16 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
             int new_candidates = agent.set_remote_candidates(stream_id, i, candidates);
             debug("Initiated component %u with %i remote candidates", i, new_candidates);
 
-            connections[i] = new DatagramConnection(agent, stream_id, i);
+            connections[i] = new DatagramConnection(agent, dtls_srtp, stream_id, i);
             content.set_transport_connection(connections[i], i);
         }
+
+        if (incoming && dtls_srtp != null) {
+            Jingle.DatagramConnection rtp_datagram = (Jingle.DatagramConnection) content.get_transport_connection(1);
+            rtp_datagram.notify["ready"].connect(() => {
+                dtls_srtp.setup_dtls_connection(false);
+            });
+        }
         base.create_transport_connection(stream, content);
     }
 
@@ -194,12 +229,17 @@ public class Dino.Plugins.Ice.TransportParameters : JingleIceUdp.IceUdpTransport
 
     private void on_recv(Nice.Agent agent, uint stream_id, uint component_id, uint8[] data) {
         if (stream_id != this.stream_id) return;
+        uint8[] decrypt_data = null;
+        if (dtls_srtp != null) {
+            decrypt_data = dtls_srtp.process_incoming_data(component_id, data);
+            if (decrypt_data == null) return;
+        }
         may_consider_ready(stream_id, component_id);
         if (connections.has_key((uint8) component_id)) {
             if (!connections[(uint8) component_id].ready) {
                 debug("on_recv stream %u component %u when state %s", stream_id, component_id, agent.get_component_state(stream_id, component_id).to_string());
             }
-            connections[(uint8) component_id].datagram_received(new Bytes(data));
+            connections[(uint8) component_id].datagram_received(new Bytes(decrypt_data ?? data));
         } else {
             debug("on_recv stream %u component %u length %u", stream_id, component_id, data.length);
         }
diff --git a/plugins/ice/vapi/gnutls.vapi b/plugins/ice/vapi/gnutls.vapi
new file mode 100644
index 00000000..a8f75e14
--- /dev/null
+++ b/plugins/ice/vapi/gnutls.vapi
@@ -0,0 +1,419 @@
+[CCode (cprefix = "gnutls_", lower_case_cprefix = "gnutls_", cheader_filename = "gnutls/gnutls.h")]
+namespace GnuTLS {
+
+    public int global_init();
+
+    [CCode (cname = "gnutls_pull_func", has_target = false)]
+    public delegate ssize_t PullFunc(void* transport_ptr, [CCode (ctype = "void*", array_length_type="size_t")] uint8[] array);
+
+    [CCode (cname = "gnutls_pull_timeout_func", has_target = false)]
+    public delegate int PullTimeoutFunc(void* transport_ptr, uint ms);
+
+    [CCode (cname = "gnutls_push_func", has_target = false)]
+    public delegate ssize_t PushFunc(void* transport_ptr, [CCode (ctype = "void*", array_length_type="size_t")] uint8[] array);
+
+    [CCode (cname = "gnutls_certificate_verify_function", has_target = false)]
+    public delegate int VerifyFunc(Session session);
+
+    [Compact]
+    [CCode (cname = "struct gnutls_session_int", free_function = "gnutls_deinit")]
+    public class Session {
+
+        public static Session? create(int con_end) throws GLib.Error {
+            Session result;
+            var ret = init(out result, con_end);
+            throw_if_error(ret);
+            return result;
+        }
+
+        [CCode (cname = "gnutls_init")]
+        private static int init(out Session session, int con_end);
+
+        [CCode (cname = "gnutls_transport_set_push_function")]
+        public void set_push_function(PushFunc func);
+
+        [CCode (cname = "gnutls_transport_set_pull_function")]
+        public void set_pull_function(PullFunc func);
+
+        [CCode (cname = "gnutls_transport_set_pull_timeout_function")]
+        public void set_pull_timeout_function(PullTimeoutFunc func);
+
+        [CCode (cname = "gnutls_transport_set_ptr")]
+        public void set_transport_pointer(void* ptr);
+
+        [CCode (cname = "gnutls_transport_get_ptr")]
+        public void* get_transport_pointer();
+
+        [CCode (cname = "gnutls_heartbeat_enable")]
+        public int enable_heartbeat(uint type);
+
+        [CCode (cname = "gnutls_certificate_server_set_request")]
+        public void server_set_request(CertificateRequest req);
+
+        [CCode (cname = "gnutls_credentials_set")]
+        public int set_credentials_(CredentialsType type, void* cred);
+        [CCode (cname = "gnutls_credentials_set_")]
+        public void set_credentials(CredentialsType type, void* cred) throws GLib.Error {
+            int err = set_credentials_(type, cred);
+            throw_if_error(err);
+        }
+
+        [CCode (cname = "gnutls_priority_set_direct")]
+        public int set_priority_from_string_(string priority, out unowned string err_pos = null);
+        [CCode (cname = "gnutls_priority_set_direct_")]
+        public void set_priority_from_string(string priority, out unowned string err_pos = null) throws GLib.Error {
+            int err = set_priority_from_string_(priority, out err_pos);
+            throw_if_error(err);
+        }
+
+        [CCode (cname = "gnutls_srtp_set_profile_direct")]
+        public int set_srtp_profile_direct_(string profiles, out unowned string err_pos = null);
+        [CCode (cname = "gnutls_srtp_set_profile_direct_")]
+        public void set_srtp_profile_direct(string profiles, out unowned string err_pos = null) throws GLib.Error {
+            int err = set_srtp_profile_direct_(profiles, out err_pos);
+            throw_if_error(err);
+        }
+
+        [CCode (cname = "gnutls_transport_set_int")]
+        public void transport_set_int(int fd);
+
+        [CCode (cname = "gnutls_handshake")]
+        public int handshake();
+
+        [CCode (cname = "gnutls_srtp_get_keys")]
+        public int get_srtp_keys_(void *key_material, uint32 key_material_size, out Datum client_key, out Datum client_salt, out Datum server_key, out Datum server_salt);
+        [CCode (cname = "gnutls_srtp_get_keys_")]
+        public void get_srtp_keys(void *key_material, uint32 key_material_size, out Datum client_key, out Datum client_salt, out Datum server_key, out Datum server_salt) throws GLib.Error {
+            get_srtp_keys_(key_material, key_material_size, out client_key, out client_salt, out server_key, out server_salt);
+        }
+
+        [CCode (cname = "gnutls_certificate_get_peers", array_length_type = "unsigned int")]
+        public unowned Datum[]? get_peer_certificates();
+
+        [CCode (cname = "gnutls_session_set_verify_function")]
+        public void set_verify_function(VerifyFunc func);
+    }
+
+    [Compact]
+    [CCode (cname = "struct gnutls_certificate_credentials_st", free_function = "gnutls_certificate_free_credentials", cprefix = "gnutls_certificate_")]
+    public class CertificateCredentials {
+
+        [CCode (cname = "gnutls_certificate_allocate_credentials")]
+        private static int allocate(out CertificateCredentials credentials);
+
+        public static CertificateCredentials create() throws GLib.Error {
+            CertificateCredentials result;
+            var ret = allocate (out result);
+            throw_if_error(ret);
+            return result;
+        }
+
+        public void get_x509_crt(uint index, [CCode (array_length_type = "unsigned int")] out unowned X509.Certificate[] x509_ca_list);
+
+        public int set_x509_key(X509.Certificate[] cert_list, X509.PrivateKey key);
+    }
+
+    [CCode (cheader_filename = "gnutls/x509.h", cprefix = "GNUTLS_")]
+    namespace X509 {
+
+        [Compact]
+        [CCode (cname = "struct gnutls_x509_crt_int", cprefix = "gnutls_x509_crt_", free_function = "gnutls_x509_crt_deinit")]
+        public class Certificate {
+
+            [CCode (cname = "gnutls_x509_crt_init")]
+            private static int init (out Certificate cert);
+            public static Certificate create() throws GLib.Error {
+                Certificate result;
+                var ret = init (out result);
+                throw_if_error(ret);
+                return result;
+            }
+
+            [CCode (cname = "gnutls_x509_crt_import")]
+            public int import_(ref Datum data, CertificateFormat format);
+            [CCode (cname = "gnutls_x509_crt_import_")]
+            public void import(ref Datum data, CertificateFormat format) throws GLib.Error {
+                int err = import_(ref data, format);
+                throw_if_error(err);
+            }
+
+            [CCode (cname = "gnutls_x509_crt_set_version")]
+            public int set_version_(uint version);
+            [CCode (cname = "gnutls_x509_crt_set_version_")]
+            public void set_version(uint version) throws GLib.Error {
+                int err = set_version_(version);
+                throw_if_error(err);
+            }
+
+            [CCode (cname = "gnutls_x509_crt_set_key")]
+            public int set_key_(PrivateKey key);
+            [CCode (cname = "gnutls_x509_crt_set_key_")]
+            public void set_key(PrivateKey key) throws GLib.Error {
+                int err = set_key_(key);
+                throw_if_error(err);
+            }
+
+            [CCode (cname = "gnutls_x509_crt_set_activation_time")]
+            public int set_activation_time_(time_t act_time);
+            [CCode (cname = "gnutls_x509_crt_set_activation_time_")]
+            public void set_activation_time(time_t act_time) throws GLib.Error {
+                int err = set_activation_time_(act_time);
+                throw_if_error(err);
+            }
+
+            [CCode (cname = "gnutls_x509_crt_set_expiration_time")]
+            public int set_expiration_time_(time_t exp_time);
+            [CCode (cname = "gnutls_x509_crt_set_expiration_time_")]
+            public void set_expiration_time(time_t exp_time) throws GLib.Error {
+                int err = set_expiration_time_(exp_time);
+                throw_if_error(err);
+            }
+
+            [CCode (cname = "gnutls_x509_crt_set_serial")]
+            public int set_serial_(void* serial, size_t serial_size);
+            [CCode (cname = "gnutls_x509_crt_set_serial_")]
+            public void set_serial(void* serial, size_t serial_size) throws GLib.Error {
+                int err = set_serial_(serial, serial_size);
+                throw_if_error(err);
+            }
+
+            [CCode (cname = "gnutls_x509_crt_sign")]
+            public int sign_(Certificate issuer, PrivateKey issuer_key);
+            [CCode (cname = "gnutls_x509_crt_sign_")]
+            public void sign(Certificate issuer, PrivateKey issuer_key) throws GLib.Error {
+                int err = sign_(issuer, issuer_key);
+                throw_if_error(err);
+            }
+
+            [CCode (cname = "gnutls_x509_crt_get_fingerprint")]
+            public int get_fingerprint_(DigestAlgorithm algo, void* buf, ref size_t buf_size);
+            [CCode (cname = "gnutls_x509_crt_get_fingerprint_")]
+            public void get_fingerprint(DigestAlgorithm algo, void* buf, ref size_t buf_size) throws GLib.Error {
+                int err = get_fingerprint_(algo, buf, ref buf_size);
+                throw_if_error(err);
+            }
+        }
+
+        [Compact]
+        [CCode (cname = "struct gnutls_x509_privkey_int", cprefix = "gnutls_x509_privkey_", free_function = "gnutls_x509_privkey_deinit")]
+        public class PrivateKey {
+            private static int init (out PrivateKey key);
+            public static PrivateKey create () throws GLib.Error {
+                PrivateKey result;
+                var ret = init (out result);
+                throw_if_error(ret);
+                return result;
+            }
+
+            public int generate(PKAlgorithm algo, uint bits, uint flags = 0);
+        }
+
+    }
+
+    [CCode (cname = "gnutls_certificate_request_t", cprefix = "GNUTLS_CERT_", has_type_id = false)]
+    public enum CertificateRequest {
+        IGNORE,
+        REQUEST,
+        REQUIRE
+    }
+
+    [CCode (cname = "gnutls_pk_algorithm_t", cprefix = "GNUTLS_PK_", has_type_id = false)]
+    public enum PKAlgorithm {
+        UNKNOWN,
+        RSA,
+        DSA;
+    }
+
+    [CCode (cname = "gnutls_digest_algorithm_t", cprefix = "GNUTLS_DIG_", has_type_id = false)]
+    public enum DigestAlgorithm {
+        NULL,
+        MD5,
+        SHA1,
+        RMD160,
+        MD2,
+        SHA224,
+        SHA256,
+        SHA384,
+        SHA512;
+    }
+
+    [Flags]
+    [CCode (cname = "gnutls_init_flags_t", cprefix = "GNUTLS_", has_type_id = false)]
+    public enum InitFlags {
+        SERVER,
+        CLIENT,
+        DATAGRAM
+    }
+
+    [CCode (cname = "gnutls_credentials_type_t", cprefix = "GNUTLS_CRD_", has_type_id = false)]
+    public enum CredentialsType {
+        CERTIFICATE,
+        ANON,
+        SRP,
+        PSK,
+        IA
+    }
+
+    [CCode (cname = "gnutls_x509_crt_fmt_t", cprefix = "GNUTLS_X509_FMT_", has_type_id = false)]
+    public enum CertificateFormat {
+        DER,
+        PEM
+    }
+
+    [Flags]
+    [CCode (cname = "gnutls_certificate_status_t", cprefix = "GNUTLS_CERT_", has_type_id = false)]
+    public enum CertificateStatus {
+        INVALID,             // will be set if the certificate was not verified.
+		REVOKED,             // in X.509 this will be set only if CRLs are checked
+		SIGNER_NOT_FOUND,
+        SIGNER_NOT_CA,
+        INSECURE_ALGORITHM
+    }
+
+    [SimpleType]
+    [CCode (cname = "gnutls_datum_t", has_type_id = false)]
+    public struct Datum {
+        public uint8* data;
+        public uint size;
+
+        public uint8[] extract() {
+            uint8[size] ret = new uint8[size];
+            for (int i = 0; i < size; i++) {
+                ret[i] = data[i];
+            }
+            return ret;
+        }
+    }
+
+    // Gnutls error codes. The mapping to a TLS alert is also shown in comments.
+    [CCode (cname = "int", cprefix = "GNUTLS_E_", lower_case_cprefix = "gnutls_error_", has_type_id = false)]
+    public enum ErrorCode {
+        SUCCESS,
+        UNKNOWN_COMPRESSION_ALGORITHM,
+        UNKNOWN_CIPHER_TYPE,
+        LARGE_PACKET,
+        UNSUPPORTED_VERSION_PACKET, // GNUTLS_A_PROTOCOL_VERSION
+        UNEXPECTED_PACKET_LENGTH, // GNUTLS_A_RECORD_OVERFLOW
+        INVALID_SESSION,
+        FATAL_ALERT_RECEIVED,
+        UNEXPECTED_PACKET, // GNUTLS_A_UNEXPECTED_MESSAGE
+        WARNING_ALERT_RECEIVED,
+        ERROR_IN_FINISHED_PACKET,
+        UNEXPECTED_HANDSHAKE_PACKET,
+        UNKNOWN_CIPHER_SUITE, // GNUTLS_A_HANDSHAKE_FAILURE
+        UNWANTED_ALGORITHM,
+        MPI_SCAN_FAILED,
+        DECRYPTION_FAILED, // GNUTLS_A_DECRYPTION_FAILED, GNUTLS_A_BAD_RECORD_MAC
+        MEMORY_ERROR,
+        DECOMPRESSION_FAILED, // GNUTLS_A_DECOMPRESSION_FAILURE
+        COMPRESSION_FAILED,
+        AGAIN,
+        EXPIRED,
+        DB_ERROR,
+        SRP_PWD_ERROR,
+        INSUFFICIENT_CREDENTIALS,
+        HASH_FAILED,
+        BASE64_DECODING_ERROR,
+        MPI_PRINT_FAILED,
+        REHANDSHAKE, // GNUTLS_A_NO_RENEGOTIATION
+        GOT_APPLICATION_DATA,
+        RECORD_LIMIT_REACHED,
+        ENCRYPTION_FAILED,
+        PK_ENCRYPTION_FAILED,
+        PK_DECRYPTION_FAILED,
+        PK_SIGN_FAILED,
+        X509_UNSUPPORTED_CRITICAL_EXTENSION,
+        KEY_USAGE_VIOLATION,
+        NO_CERTIFICATE_FOUND, // GNUTLS_A_BAD_CERTIFICATE
+        INVALID_REQUEST,
+        SHORT_MEMORY_BUFFER,
+        INTERRUPTED,
+        PUSH_ERROR,
+        PULL_ERROR,
+        RECEIVED_ILLEGAL_PARAMETER, // GNUTLS_A_ILLEGAL_PARAMETER
+        REQUESTED_DATA_NOT_AVAILABLE,
+        PKCS1_WRONG_PAD,
+        RECEIVED_ILLEGAL_EXTENSION,
+        INTERNAL_ERROR,
+        DH_PRIME_UNACCEPTABLE,
+        FILE_ERROR,
+        TOO_MANY_EMPTY_PACKETS,
+        UNKNOWN_PK_ALGORITHM,
+        // returned if libextra functionality was requested but
+        // gnutls_global_init_extra() was not called.
+
+        INIT_LIBEXTRA,
+        LIBRARY_VERSION_MISMATCH,
+        // returned if you need to generate temporary RSA
+        // parameters. These are needed for export cipher suites.
+
+        NO_TEMPORARY_RSA_PARAMS,
+        LZO_INIT_FAILED,
+        NO_COMPRESSION_ALGORITHMS,
+        NO_CIPHER_SUITES,
+        OPENPGP_GETKEY_FAILED,
+        PK_SIG_VERIFY_FAILED,
+        ILLEGAL_SRP_USERNAME,
+        SRP_PWD_PARSING_ERROR,
+        NO_TEMPORARY_DH_PARAMS,
+        // For certificate and key stuff
+
+        ASN1_ELEMENT_NOT_FOUND,
+        ASN1_IDENTIFIER_NOT_FOUND,
+        ASN1_DER_ERROR,
+        ASN1_VALUE_NOT_FOUND,
+        ASN1_GENERIC_ERROR,
+        ASN1_VALUE_NOT_VALID,
+        ASN1_TAG_ERROR,
+        ASN1_TAG_IMPLICIT,
+        ASN1_TYPE_ANY_ERROR,
+        ASN1_SYNTAX_ERROR,
+        ASN1_DER_OVERFLOW,
+        OPENPGP_UID_REVOKED,
+        CERTIFICATE_ERROR,
+        CERTIFICATE_KEY_MISMATCH,
+        UNSUPPORTED_CERTIFICATE_TYPE, // GNUTLS_A_UNSUPPORTED_CERTIFICATE
+        X509_UNKNOWN_SAN,
+        OPENPGP_FINGERPRINT_UNSUPPORTED,
+        X509_UNSUPPORTED_ATTRIBUTE,
+        UNKNOWN_HASH_ALGORITHM,
+        UNKNOWN_PKCS_CONTENT_TYPE,
+        UNKNOWN_PKCS_BAG_TYPE,
+        INVALID_PASSWORD,
+        MAC_VERIFY_FAILED, // for PKCS #12 MAC
+        CONSTRAINT_ERROR,
+        WARNING_IA_IPHF_RECEIVED,
+        WARNING_IA_FPHF_RECEIVED,
+        IA_VERIFY_FAILED,
+        UNKNOWN_ALGORITHM,
+        BASE64_ENCODING_ERROR,
+        INCOMPATIBLE_CRYPTO_LIBRARY,
+        INCOMPATIBLE_LIBTASN1_LIBRARY,
+        OPENPGP_KEYRING_ERROR,
+        X509_UNSUPPORTED_OID,
+        RANDOM_FAILED,
+        BASE64_UNEXPECTED_HEADER_ERROR,
+        OPENPGP_SUBKEY_ERROR,
+        CRYPTO_ALREADY_REGISTERED,
+        HANDSHAKE_TOO_LARGE,
+        UNIMPLEMENTED_FEATURE,
+        APPLICATION_ERROR_MAX, // -65000
+        APPLICATION_ERROR_MIN; // -65500
+
+        [CCode (cname = "gnutls_error_is_fatal")]
+        public bool is_fatal();
+
+        [CCode (cname = "gnutls_perror")]
+        public void print();
+
+        [CCode (cname = "gnutls_strerror")]
+        public unowned string to_string();
+    }
+
+    public void throw_if_error(int err_int) throws GLib.Error {
+        ErrorCode error = (ErrorCode)err_int;
+        if (error != ErrorCode.SUCCESS) {
+            throw new GLib.Error(-1, error, "%s%s", error.to_string(), error.is_fatal() ? " fatal" : "");
+        }
+    }
+}
\ No newline at end of file
diff --git a/plugins/rtp/CMakeLists.txt b/plugins/rtp/CMakeLists.txt
index 5311fac3..8ce2a7c6 100644
--- a/plugins/rtp/CMakeLists.txt
+++ b/plugins/rtp/CMakeLists.txt
@@ -2,6 +2,7 @@ find_packages(RTP_PACKAGES REQUIRED
     Gee
     GLib
     GModule
+    GnuTLS
     GObject
     GTK3
     Gst