Add file receiving via Jingle

This currently follows the same rules as HTTP file download for
accepting files.

5 files changed, 731 insertions, 268 deletions

diff --git a/xmpp-vala/src/module/xep/0047_in_band_bytestreams.vala b/xmpp-vala/src/module/xep/0047_in_band_bytestreams.vala
index 0e1dd6be..ea9d5f72 100644
--- a/xmpp-vala/src/module/xep/0047_in_band_bytestreams.vala
+++ b/xmpp-vala/src/module/xep/0047_in_band_bytestreams.vala
@@ -7,56 +7,111 @@ namespace Xmpp.Xep.InBandBytestreams {
 private const string NS_URI = "http://jabber.org/protocol/ibb";
 private const int SEQ_MODULUS = 65536;
 
-public class Module : XmppStreamModule {
+public class Module : XmppStreamModule, Iq.Handler {
     public static Xmpp.ModuleIdentity<Module> IDENTITY = new Xmpp.ModuleIdentity<Module>(NS_URI, "0047_in_band_bytestreams");
 
     public override void attach(XmppStream stream) {
         stream.add_flag(new Flag());
+        stream.get_module(Iq.Module.IDENTITY).register_for_namespace(NS_URI, this);
     }
     public override void detach(XmppStream stream) { }
 
     public void on_iq_set(XmppStream stream, Iq.Stanza iq) {
-        StanzaNode? data = iq.stanza.get_subnode("data", NS_URI);
-        string? sid = data != null ? data.get_attribute("sid") : null;
-        if (data == null || sid == null) {
-            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.bad_request("missing data node or sid")));
+        // the iq module ensures that there's only one child node
+        StanzaNode? node = null;
+        node = (node != null) ? node : iq.stanza.get_subnode("open", NS_URI);
+        node = (node != null) ? node : iq.stanza.get_subnode("data", NS_URI);
+        node = (node != null) ? node : iq.stanza.get_subnode("close", NS_URI);
+        if (node == null) {
+            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.bad_request("unknown IBB action")));
             return;
         }
-        Connection? conn = stream.get_flag(Flag.IDENTITY).get_connection(sid);
-        if (conn == null) {
-            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.item_not_found()));
+        string? sid = node.get_attribute("sid");
+        if (sid == null) {
+            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.bad_request("missing sid")));
             return;
         }
-
-        int seq = data.get_attribute_int("seq");
-        // TODO(hrxi): return an error on malformed base64 (need to do this
-        // according to the xep)
-        uint8[] content = Base64.decode(data.get_string_content());
-        if (seq < 0 || seq != conn.remote_seq) {
-            // TODO(hrxi): send an error and close the connection
-            return;
+        Connection? conn = stream.get_flag(Flag.IDENTITY).get_connection(sid);
+        if (node.name == "open") {
+            if (conn == null) {
+                stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.not_acceptable("unexpected IBB connection")));
+                return;
+            }
+            if (conn.state != WAITING_FOR_CONNECT) {
+                stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.bad_request("IBB open for already open connection")));
+                return;
+            }
+            conn.handle_open(stream, node, iq);
+        } else {
+            if (conn == null || conn.state != Connection.State.CONNECTED) {
+                stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.item_not_found()));
+                return;
+            }
+            if (node.name == "close") {
+                conn.handle_close(stream, node, iq);
+            } else {
+                conn.handle_data(stream, node, iq);
+            }
         }
-        conn.remote_seq = (conn.remote_seq + 1) % SEQ_MODULUS;
-
-        stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.result(iq));
-        conn.on_data(stream, content);
     }
 
     public override string get_ns() { return NS_URI; }
     public override string get_id() { return IDENTITY.id; }
 }
 
-public class Connection {
-    // TODO(hrxi): implement half-open states
+public class Connection : IOStream {
+    // TODO(hrxi): Fix reference cycle
+    public class Input : InputStream {
+        private Connection connection;
+        public Input(Connection connection) {
+            this.connection = connection;
+        }
+        public override ssize_t read(uint8[] buffer, Cancellable? cancellable = null) throws IOError {
+            throw new IOError.NOT_SUPPORTED("can't do non-async reads on in-band bytestreams");
+        }
+        public override async ssize_t read_async(uint8[]? buffer, int io_priority = GLib.Priority.DEFAULT, Cancellable? cancellable = null) throws IOError {
+            return yield connection.read_async(buffer, io_priority, cancellable);
+        }
+        public override bool close(Cancellable? cancellable = null) throws IOError {
+            return connection.close_read(cancellable);
+        }
+        public override async bool close_async(int io_priority = GLib.Priority.DEFAULT, Cancellable? cancellable = null) throws IOError {
+            return yield connection.close_read_async(io_priority, cancellable);
+        }
+    }
+    public class Output : OutputStream {
+        private Connection connection;
+        public Output(Connection connection) {
+            this.connection = connection;
+        }
+        public override ssize_t write(uint8[] buffer, Cancellable? cancellable = null) throws IOError {
+            throw new IOError.NOT_SUPPORTED("can't do non-async writes on in-band bytestreams");
+        }
+        public override async ssize_t write_async(uint8[]? buffer, int io_priority = GLib.Priority.DEFAULT, Cancellable? cancellable = null) throws IOError {
+            return yield connection.write_async(buffer, io_priority, cancellable);
+        }
+        public override bool close(Cancellable? cancellable = null) throws IOError {
+            return connection.close_write(cancellable);
+        }
+        public override async bool close_async(int io_priority = GLib.Priority.DEFAULT, Cancellable? cancellable = null) throws IOError {
+            return yield connection.close_write_async(io_priority, cancellable);
+        }
+    }
+
+    private Input input;
+    private Output output;
+    public override InputStream input_stream { get { return input; } }
+    public override OutputStream output_stream { get { return output; } }
+
     public enum State {
-        UNCONNECTED,
+        WAITING_FOR_CONNECT,
         CONNECTING,
         CONNECTED,
         DISCONNECTING,
         DISCONNECTED,
         ERROR,
     }
-    State state = UNCONNECTED;
+    public State state { get; private set; }
     Jid receiver_full_jid;
     public string sid { get; private set; }
     int block_size;
@@ -64,76 +119,161 @@ public class Connection {
     int remote_ack = 0;
     internal int remote_seq = 0;
 
-    public signal void on_error(XmppStream stream, string error);
-    public signal void on_data(XmppStream stream, uint8[] data);
-    public signal void on_ready(XmppStream stream);
+    bool input_closed = false;
+    bool output_closed = false;
 
-    public Connection(Jid receiver_full_jid, string sid, int block_size) {
+    // ERROR
+    string? error = null;
+
+    XmppStream stream;
+
+    SourceFunc? read_callback = null;
+    SourceFunc? write_callback = null;
+    // Need `Bytes` instead of `uint8[]` because the latter doesn't work in
+    // parameter position of `LinkedList`.
+    LinkedList<Bytes> received = new LinkedList<Bytes>();
+
+    private Connection(XmppStream stream, Jid receiver_full_jid, string sid, int block_size, bool initiate) {
+        this.stream = stream;
         this.receiver_full_jid = receiver_full_jid;
         this.sid = sid;
         this.block_size = block_size;
-    }
+        this.state = initiate ? State.CONNECTING : State.WAITING_FOR_CONNECT;
 
-    public void connect(XmppStream stream) {
-        assert(state == UNCONNECTED);
-        state = CONNECTING;
-
-        StanzaNode open = new StanzaNode.build("open", NS_URI)
-            .add_self_xmlns()
-            .put_attribute("block-size", block_size.to_string())
-            .put_attribute("sid", sid);
+        input = new Input(this);
+        output = new Output(this);
+    }
 
-        Iq.Stanza iq = new Iq.Stanza.set(open) { to=receiver_full_jid };
-        stream.get_module(Iq.Module.IDENTITY).send_iq(stream, iq, (stream, iq) => {
-            assert(state == CONNECTING);
-            if (!iq.is_error()) {
-                state = CONNECTED;
-                stream.get_flag(Flag.IDENTITY).add_connection(this);
-                on_ready(stream);
-            } else {
-                set_error(stream, "connection failed");
-            }
-        });
+    public void set_read_calllback(SourceFunc callback) throws IOError {
+        if (read_callback != null) {
+            throw new IOError.PENDING("only one async read is permitted at a time on an in-band bytestream");
+        }
+        read_callback = callback;
+    }
+    public void set_write_calllback(SourceFunc callback) throws IOError {
+        if (write_callback != null) {
+            throw new IOError.PENDING("only one async write is permitted at a time on an in-band bytestream");
+        }
+        write_callback = callback;
+    }
+    public void trigger_read_callback() {
+        if (read_callback != null) {
+            Idle.add((owned) read_callback);
+            read_callback = null;
+        }
+    }
+    public void trigger_write_callback() {
+        if (write_callback != null) {
+            Idle.add((owned) write_callback);
+            write_callback = null;
+        }
     }
 
-    void set_error(XmppStream stream, string error) {
-        // TODO(hrxi): Send disconnect?
-        state = ERROR;
-        on_error(stream, error);
+    public async ssize_t read_async(uint8[]? buffer, int io_priority = GLib.Priority.DEFAULT, Cancellable? cancellable = null) throws IOError {
+        // TODO(hrxi): cancellable?
+        // TODO(hrxi): io_priority?
+        while (true) {
+            if (input_closed) {
+                return 0;
+            }
+            Bytes? chunk = received.poll();
+            if (chunk != null) {
+                int read = int.min(buffer.length, chunk.length);
+                for (int i = 0; i < read; i++) {
+                    buffer[i] = chunk[i];
+                }
+                if (buffer.length < chunk.length) {
+                    received.offer_head(chunk[buffer.length:chunk.length]);
+                }
+                return read;
+            }
+            if (state == DISCONNECTED) {
+                return 0;
+            }
+            set_read_calllback(read_async.callback);
+            yield;
+        }
     }
 
-    public void send(XmppStream stream, uint8[] bytes) {
+    public async ssize_t write_async(uint8[]? buffer, int io_priority = GLib.Priority.DEFAULT, Cancellable? cancellable = null) throws IOError {
+        while (state == WAITING_FOR_CONNECT || state == CONNECTING) {
+            set_write_calllback(write_async.callback);
+            yield;
+        }
+        throw_if_closed();
         assert(state == CONNECTED);
-        // TODO(hrxi): rate-limiting/merging?
+        // TODO(hrxi): merging?
         int seq = local_seq;
         local_seq = (local_seq + 1) % SEQ_MODULUS;
+        if (buffer.length > block_size) {
+            buffer = buffer[0:block_size];
+        }
         StanzaNode data = new StanzaNode.build("data", NS_URI)
             .add_self_xmlns()
             .put_attribute("sid", sid)
             .put_attribute("seq", seq.to_string())
-            .put_node(new StanzaNode.text(Base64.encode(bytes)));
+            .put_node(new StanzaNode.text(Base64.encode(buffer)));
         Iq.Stanza iq = new Iq.Stanza.set(data) { to=receiver_full_jid };
+        set_write_calllback(write_async.callback);
         stream.get_module(Iq.Module.IDENTITY).send_iq(stream, iq, (stream, iq) => {
             if (iq.is_error()) {
-                set_error(stream, "sending failed");
-                return;
-            }
-            if (remote_ack != seq) {
-                set_error(stream, "out of order acks");
-                return;
-            }
-            remote_ack = (remote_ack + 1) % SEQ_MODULUS;
-            if (local_seq == remote_ack) {
-                on_ready(stream);
+                set_error("sending failed");
+            } else if (remote_ack != seq) {
+                set_error("out of order acks");
+            } else {
+                remote_ack = (remote_ack + 1) % SEQ_MODULUS;
+                if (local_seq == remote_ack) {
+                    trigger_write_callback();
+                }
             }
         });
+        yield;
+        throw_if_error();
+        return buffer.length;
     }
 
-    public void close(XmppStream stream) {
-        assert(state == CONNECTED);
+    public bool close_read(Cancellable? cancellable = null) {
+        input_closed = true;
+        if (!output_closed) {
+            return true;
+        }
+        return close_impl(cancellable);
+    }
+    public async bool close_read_async(int io_priority = GLib.Priority.DEFAULT, Cancellable? cancellable = null) throws IOError {
+        input_closed = true;
+        if (!output_closed) {
+            return true;
+        }
+        return yield close_async_impl(io_priority, cancellable);
+    }
+    public bool close_write(Cancellable? cancellable = null) {
+        output_closed = true;
+        if (!input_closed) {
+            return true;
+        }
+        return close_impl(cancellable);
+    }
+    public async bool close_write_async(int io_priority = GLib.Priority.DEFAULT, Cancellable? cancellable = null) throws IOError {
+        output_closed = true;
+        if (!input_closed) {
+            return true;
+        }
+        return yield close_async_impl(io_priority, cancellable);
+    }
+    delegate void OnClose(bool success);
+    private bool close_impl(Cancellable? cancellable = null, OnClose? on_close = null) {
+        if (state == DISCONNECTING || state == DISCONNECTED || state == ERROR) {
+            on_close(true);
+            return true;
+        }
+        if (state == WAITING_FOR_CONNECT) {
+            state = DISCONNECTED;
+            stream.get_flag(Flag.IDENTITY).remove_connection(this);
+            trigger_read_callback();
+            on_close(true);
+            return true;
+        }
         state = DISCONNECTING;
-        // TODO(hrxi): should not do this, might still receive data
-        stream.get_flag(Flag.IDENTITY).remove_connection(this);
         StanzaNode close = new StanzaNode.build("close", NS_URI)
             .add_self_xmlns()
             .put_attribute("sid", sid);
@@ -141,11 +281,136 @@ public class Connection {
         stream.get_module(Iq.Module.IDENTITY).send_iq(stream, iq, (stream, iq) => {
             assert(state == DISCONNECTING);
             if (iq.is_error()) {
-                set_error(stream, "disconnecting failed");
-                return;
+                set_error("disconnecting failed");
+            } else {
+                state = DISCONNECTED;
             }
-            state = DISCONNECTED;
+            stream.get_flag(Flag.IDENTITY).remove_connection(this);
+            trigger_read_callback();
+            on_close(!iq.is_error());
         });
+        return true;
+    }
+    private async bool close_async_impl(int io_priority = GLib.Priority.DEFAULT, Cancellable? cancellable = null) throws IOError {
+        SourceFunc callback = close_async_impl.callback;
+        close_impl(cancellable, () => { Idle.add((owned) callback); });
+        yield;
+        throw_if_error();
+        return true;
+    }
+
+    public static Connection create(XmppStream stream, Jid receiver_full_jid, string sid, int block_size, bool initiate) {
+        Connection conn = new Connection(stream, receiver_full_jid, sid, block_size, initiate);
+        if (initiate) {
+            StanzaNode open = new StanzaNode.build("open", NS_URI)
+                .add_self_xmlns()
+                .put_attribute("block-size", block_size.to_string())
+                .put_attribute("sid", sid);
+
+            Iq.Stanza iq = new Iq.Stanza.set(open) { to=receiver_full_jid };
+            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, iq, (stream, iq) => {
+                if (conn.state != CONNECTING) {
+                    assert(conn.state != CONNECTED);
+                    return;
+                }
+                if (!iq.is_error()) {
+                    conn.state = CONNECTED;
+                    stream.get_flag(Flag.IDENTITY).add_connection(conn);
+                    conn.trigger_write_callback();
+                } else {
+                    conn.set_error("connection failed");
+                }
+            });
+        } else {
+            stream.get_flag(Flag.IDENTITY).add_connection(conn);
+        }
+        return conn;
+    }
+
+    void throw_if_error() throws IOError {
+        if (state == ERROR) {
+            throw new IOError.FAILED(error);
+        }
+    }
+
+    void throw_if_closed() throws IOError {
+        throw_if_error();
+        if (state == DISCONNECTING || state == DISCONNECTED) {
+            throw new IOError.CLOSED("can't read/write on a closed connection");
+        }
+    }
+
+    void set_error(string error) {
+        if (state != WAITING_FOR_CONNECT && state != DISCONNECTING && state != DISCONNECTED && state != ERROR) {
+            close_async.begin();
+        }
+        state = ERROR;
+        this.error = error;
+        stream.get_flag(Flag.IDENTITY).remove_connection(this);
+    }
+
+    public void handle_open(XmppStream stream, StanzaNode open, Iq.Stanza iq) {
+        assert(state == WAITING_FOR_CONNECT);
+        int block_size = open.get_attribute_int("block-size");
+        string? stanza = open.get_attribute("stanza");
+        if (block_size < 0 || (stanza != null && stanza != "iq" && stanza != "message")) {
+            set_error("invalid open");
+            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.bad_request("missing block_size or invalid stanza")));
+            return;
+        }
+        if (stanza != null && stanza != "iq") {
+            set_error("invalid open");
+            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.feature_not_implemented("cannot use message stanzas for IBB")));
+            return;
+        }
+        if (block_size > this.block_size) {
+            set_error("invalid open");
+            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.build(ErrorStanza.TYPE_CANCEL, ErrorStanza.CONDITION_RESOURCE_CONSTRAINT, "opening a connection with a greater than negotiated/acceptable block size", null)));
+            return;
+        }
+        this.block_size = block_size;
+        state = CONNECTED;
+        stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.result(iq));
+        trigger_write_callback();
+    }
+    public void handle_data(XmppStream stream, StanzaNode data, Iq.Stanza iq) {
+        assert(state == CONNECTED);
+        if (input_closed) {
+            set_error("unexpected data");
+            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.not_allowed("unexpected data")));
+            return;
+        }
+        int seq = data.get_attribute_int("seq");
+        // TODO(hrxi): return an error on malformed base64 (need to do this
+        // according to the xep)
+        uint8[] content = Base64.decode(data.get_string_content());
+        if (content.length > block_size) {
+            set_error("data longer than negotiated block size");
+            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.bad_request("data longer than negotiated block size")));
+            return;
+        }
+        if (seq < 0 || seq != remote_seq) {
+            set_error("out of order data packets");
+            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.build(ErrorStanza.TYPE_CANCEL, ErrorStanza.CONDITION_UNEXPECTED_REQUEST, "out of order data packets", null)));
+            return;
+        }
+        remote_seq = (remote_seq + 1) % SEQ_MODULUS;
+
+        stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.result(iq));
+        if (content.length != 0) {
+            received.offer(new Bytes.take(content));
+            trigger_read_callback();
+        }
+    }
+    public void handle_close(XmppStream stream, StanzaNode close, Iq.Stanza iq) {
+        assert(state == CONNECTED);
+        stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.result(iq));
+        stream.get_flag(Flag.IDENTITY).remove_connection(this);
+        input_closed = true;
+        output_closed = true;
+        state = DISCONNECTED;
+
+        trigger_read_callback();
     }
 }
 
diff --git a/xmpp-vala/src/module/xep/0048_bookmarks/conference.vala b/xmpp-vala/src/module/xep/0048_bookmarks/conference.vala
index c00d8f86..7f80490b 100644
--- a/xmpp-vala/src/module/xep/0048_bookmarks/conference.vala
+++ b/xmpp-vala/src/module/xep/0048_bookmarks/conference.vala
@@ -36,7 +36,7 @@ public class Conference : Object {
     public string? nick {
         get {
             StanzaNode? nick_node = stanza_node.get_subnode(NODE_NICK);
-            return nick_node == null? null : nick_node.get_string_content();
+            return nick_node == null ? null : nick_node.get_string_content();
         }
         set {
             StanzaNode? nick_node = stanza_node.get_subnode(NODE_NICK);
@@ -56,7 +56,7 @@ public class Conference : Object {
     public string? password {
         get {
             StanzaNode? password_node = stanza_node.get_subnode(NODE_PASSWORD);
-            return password_node == null? null : password_node.get_string_content();
+            return password_node == null ? null : password_node.get_string_content();
         }
         set {
             StanzaNode? password_node = stanza_node.get_subnode(NODE_PASSWORD);
diff --git a/xmpp-vala/src/module/xep/0166_jingle.vala b/xmpp-vala/src/module/xep/0166_jingle.vala
index 5c086399..7413ff4f 100644
--- a/xmpp-vala/src/module/xep/0166_jingle.vala
+++ b/xmpp-vala/src/module/xep/0166_jingle.vala
@@ -7,9 +7,28 @@ namespace Xmpp.Xep.Jingle {
 private const string NS_URI = "urn:xmpp:jingle:1";
 private const string ERROR_NS_URI = "urn:xmpp:jingle:errors:1";
 
-public errordomain CreateConnectionError {
+public errordomain IqError {
     BAD_REQUEST,
     NOT_ACCEPTABLE,
+    NOT_IMPLEMENTED,
+    OUT_OF_ORDER,
+}
+
+void send_iq_error(IqError iq_error, XmppStream stream, Iq.Stanza iq) {
+    ErrorStanza error;
+    if (iq_error is IqError.BAD_REQUEST) {
+        error = new ErrorStanza.bad_request(iq_error.message);
+    } else if (iq_error is IqError.NOT_ACCEPTABLE) {
+        error = new ErrorStanza.not_acceptable(iq_error.message);
+    } else if (iq_error is IqError.NOT_IMPLEMENTED) {
+        error = new ErrorStanza.feature_not_implemented(iq_error.message);
+    } else if (iq_error is IqError.OUT_OF_ORDER) {
+        StanzaNode out_of_order = new StanzaNode.build("out-of-order", ERROR_NS_URI).add_self_xmlns();
+        error = new ErrorStanza.build(ErrorStanza.TYPE_MODIFY, ErrorStanza.CONDITION_UNEXPECTED_REQUEST, iq_error.message, out_of_order);
+    } else {
+        assert_not_reached();
+    }
+    stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, error));
 }
 
 public errordomain Error {
@@ -21,9 +40,28 @@ public errordomain Error {
     TRANSPORT_ERROR,
 }
 
+StanzaNode get_single_node_anyns(StanzaNode parent, string node_name) throws IqError {
+    StanzaNode? result = null;
+    foreach (StanzaNode child in parent.get_all_subnodes()) {
+        if (child.name == node_name) {
+            if (result != null) {
+                throw new IqError.BAD_REQUEST(@"multiple $(node_name) nodes");
+            }
+            result = child;
+        }
+    }
+    if (result == null) {
+        throw new IqError.BAD_REQUEST(@"missing $(node_name) node");
+    }
+    return result;
+}
+
 public class Module : XmppStreamModule, Iq.Handler {
     public static Xmpp.ModuleIdentity<Module> IDENTITY = new Xmpp.ModuleIdentity<Module>(NS_URI, "0166_jingle");
 
+    private HashMap<string, ContentType> content_types = new HashMap<string, ContentType>();
+    private HashMap<string, Transport> transports = new HashMap<string, Transport>();
+
     public override void attach(XmppStream stream) {
         stream.add_flag(new Flag());
         stream.get_module(ServiceDiscovery.Module.IDENTITY).add_feature(stream, NS_URI);
@@ -31,11 +69,35 @@ public class Module : XmppStreamModule, Iq.Handler {
     }
     public override void detach(XmppStream stream) { }
 
-    public void add_transport(XmppStream stream, Transport transport) {
-        stream.get_flag(Flag.IDENTITY).add_transport(transport);
+    public void register_content_type(ContentType content_type) {
+        content_types[content_type.content_type_ns_uri()] = content_type;
+    }
+    public ContentType? get_content_type(string ns_uri) {
+        if (!content_types.has_key(ns_uri)) {
+            return null;
+        }
+        return content_types[ns_uri];
+    }
+    public void register_transport(Transport transport) {
+        transports[transport.transport_ns_uri()] = transport;
+    }
+    public Transport? get_transport(string ns_uri) {
+        if (!transports.has_key(ns_uri)) {
+            return null;
+        }
+        return transports[ns_uri];
     }
     public Transport? select_transport(XmppStream stream, TransportType type, Jid receiver_full_jid) {
-        return stream.get_flag(Flag.IDENTITY).select_transport(stream, type, receiver_full_jid);
+        foreach (Transport transport in transports.values) {
+            if (transport.transport_type() != type) {
+                continue;
+            }
+            // TODO(hrxi): prioritization
+            if (transport.is_transport_available(stream, receiver_full_jid)) {
+                return transport;
+            }
+        }
+        return null;
     }
 
     private bool is_jingle_available(XmppStream stream, Jid full_jid) {
@@ -59,13 +121,14 @@ public class Module : XmppStreamModule, Iq.Handler {
         if (my_jid == null) {
             throw new Error.GENERAL("Couldn't determine own JID");
         }
-        Session session = new Session(random_uuid(), type, receiver_full_jid);
+        TransportParameters transport_params = transport.create_transport_parameters();
+        Session session = new Session.initiate_sent(random_uuid(), type, transport_params, receiver_full_jid, content_name);
         StanzaNode content = new StanzaNode.build("content", NS_URI)
             .put_attribute("creator", "initiator")
             .put_attribute("name", content_name)
             .put_attribute("senders", senders.to_string())
             .put_node(description)
-            .put_node(transport.to_transport_stanza_node());
+            .put_node(transport_params.to_transport_stanza_node());
         StanzaNode jingle = new StanzaNode.build("jingle", NS_URI)
             .add_self_xmlns()
             .put_attribute("action", "session-initiate")
@@ -75,21 +138,84 @@ public class Module : XmppStreamModule, Iq.Handler {
         Iq.Stanza iq = new Iq.Stanza.set(jingle) { to=receiver_full_jid };
 
         stream.get_module(Iq.Module.IDENTITY).send_iq(stream, iq, (stream, iq) => {
+            // TODO(hrxi): handle errors
             stream.get_flag(Flag.IDENTITY).add_session(session);
         });
 
         return session;
     }
 
+    public void handle_session_initiate(XmppStream stream, string sid, StanzaNode jingle, Iq.Stanza iq) throws IqError {
+        Gee.List<StanzaNode> contents = jingle.get_subnodes("content");
+        if (contents.size == 0) {
+            throw new IqError.BAD_REQUEST("missing content node");
+        }
+        if (contents.size > 1) {
+            throw new IqError.NOT_IMPLEMENTED("can't process multiple content nodes");
+        }
+        StanzaNode content = contents[0];
+        string? name = content.get_attribute("name");
+        StanzaNode description = get_single_node_anyns(content, "description");
+        StanzaNode transport_node = get_single_node_anyns(content, "transport");
+        if (name == null) {
+            throw new IqError.BAD_REQUEST("missing name");
+        }
+
+        Transport? transport = get_transport(transport_node.ns_uri);
+        TransportParameters? transport_params = null;
+        if (transport != null) {
+            transport_params = transport.parse_transport_parameters(transport_node);
+        } else {
+            // terminate the session below
+        }
+
+        ContentType? content_type = get_content_type(description.ns_uri);
+        if (content_type == null) {
+            // TODO(hrxi): how do we signal an unknown content type?
+            throw new IqError.NOT_IMPLEMENTED("unknown content type");
+        }
+        ContentParameters content_params = content_type.parse_content_parameters(description);
+
+        TransportType type = content_type.content_type_transport_type();
+        Session session = new Session.initiate_received(sid, type, transport_params, iq.from, name);
+        stream.get_flag(Flag.IDENTITY).add_session(session);
+        stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.result(iq));
+
+        if (transport == null || transport.transport_type() != type) {
+            StanzaNode reason = new StanzaNode.build("reason", NS_URI)
+                .put_node(new StanzaNode.build("unsupported-transports", NS_URI));
+            session.terminate(stream, reason);
+            return;
+        }
+
+        content_params.on_session_initiate(stream, session);
+    }
+
     public void on_iq_set(XmppStream stream, Iq.Stanza iq) {
+        try {
+            handle_iq_set(stream, iq);
+        } catch (IqError e) {
+            send_iq_error(e, stream, iq);
+        }
+    }
+
+    public void handle_iq_set(XmppStream stream, Iq.Stanza iq) throws IqError {
         StanzaNode? jingle = iq.stanza.get_subnode("jingle", NS_URI);
         string? sid = jingle != null ? jingle.get_attribute("sid") : null;
         string? action = jingle != null ? jingle.get_attribute("action") : null;
         if (jingle == null || sid == null || action == null) {
-            stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.bad_request("missing jingle node, sid or action")));
-            return;
+            throw new IqError.BAD_REQUEST("missing jingle node, sid or action");
         }
         Session? session = stream.get_flag(Flag.IDENTITY).get_session(sid);
+        if (action == "session-initiate") {
+            if (session != null) {
+                // TODO(hrxi): Info leak if other clients use predictable session IDs?
+                stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.build(ErrorStanza.TYPE_MODIFY, ErrorStanza.CONDITION_CONFLICT, "session ID already in use", null)));
+                return;
+            }
+            handle_session_initiate(stream, sid, jingle, iq);
+            return;
+        }
         if (session == null) {
             StanzaNode unknown_session = new StanzaNode.build("unknown-session", ERROR_NS_URI).add_self_xmlns();
             stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.error(iq, new ErrorStanza.item_not_found(unknown_session)));
@@ -125,62 +251,118 @@ public enum Senders {
 }
 
 public interface Transport : Object {
+    public abstract string transport_ns_uri();
     public abstract bool is_transport_available(XmppStream stream, Jid full_jid);
     public abstract TransportType transport_type();
+    public abstract TransportParameters create_transport_parameters();
+    public abstract TransportParameters parse_transport_parameters(StanzaNode transport) throws IqError;
+}
+
+public interface TransportParameters : Object {
+    public abstract string transport_ns_uri();
     public abstract StanzaNode to_transport_stanza_node();
-    public abstract Connection? create_transport_connection(XmppStream stream, Jid peer_full_jid, StanzaNode content) throws CreateConnectionError;
+    public abstract void update_transport(StanzaNode transport) throws IqError;
+    public abstract IOStream create_transport_connection(XmppStream stream, Jid peer_full_jid, Role role);
+}
+
+public enum Role {
+    INITIATOR,
+    RESPONDER;
+
+    public string to_string() {
+        switch (this) {
+            case INITIATOR: return "initiator";
+            case RESPONDER: return "responder";
+        }
+        assert_not_reached();
+    }
+}
+
+public interface ContentType : Object {
+    public abstract string content_type_ns_uri();
+    public abstract TransportType content_type_transport_type();
+    public abstract ContentParameters parse_content_parameters(StanzaNode description) throws IqError;
+}
+
+public interface ContentParameters : Object {
+    public abstract void on_session_initiate(XmppStream stream, Session session);
 }
 
+
 public class Session {
+    // INITIATE_SENT -> ACTIVE -> ENDED
+    // INITIATE_RECEIVED -> ACTIVE -> ENDED
     public enum State {
-        PENDING,
+        INITIATE_SENT,
+        INITIATE_RECEIVED,
         ACTIVE,
         ENDED,
     }
 
     public State state { get; private set; }
-    Connection? conn;
 
     public string sid { get; private set; }
     public Type type_ { get; private set; }
     public Jid peer_full_jid { get; private set; }
+    public string content_name { get; private set; }
 
-    public Session(string sid, Type type, Jid peer_full_jid) {
-        this.state = PENDING;
-        this.conn = null;
+    // INITIATE_SENT | INITIATE_RECEIVED
+    TransportParameters? transport = null;
+
+    // ACTIVE
+    public IOStream? conn { get; private set; }
+
+    // Only interesting in INITIATE_SENT.
+    // Signals that the session has been accepted by the peer.
+    public signal void accepted(XmppStream stream);
+
+    public Session.initiate_sent(string sid, Type type, TransportParameters transport, Jid peer_full_jid, string content_name) {
+        this.state = INITIATE_SENT;
         this.sid = sid;
         this.type_ = type;
         this.peer_full_jid = peer_full_jid;
+        this.content_name = content_name;
+        this.transport = transport;
+        this.conn = null;
     }
 
-    public signal void on_error(XmppStream stream, Error error);
-    public signal void on_data(XmppStream stream, uint8[] data);
-    // Signals that the stream is ready to send (more) data.
-    public signal void on_ready(XmppStream stream);
-
-    private void handle_error(XmppStream stream, Error error) {
-        if (state == PENDING || state == ACTIVE) {
-            StanzaNode reason = new StanzaNode.build("reason", NS_URI)
-                .put_node(new StanzaNode.build("general-error", NS_URI)) // TODO(hrxi): Is this the right error?
-                .put_node(new StanzaNode.build("text", NS_URI)
-                    .put_node(new StanzaNode.text(error.message))
-                );
-            terminate(stream, reason);
-        }
+    public Session.initiate_received(string sid, Type type, TransportParameters? transport, Jid peer_full_jid, string content_name) {
+        this.state = INITIATE_RECEIVED;
+        this.sid = sid;
+        this.type_ = type;
+        this.peer_full_jid = peer_full_jid;
+        this.content_name = content_name;
+        this.transport = transport;
+        this.conn = null;
     }
 
-    delegate void SendIq(Iq.Stanza iq);
-    public void handle_iq_set(XmppStream stream, string action, StanzaNode jingle, Iq.Stanza iq) {
-        SendIq send_iq = (iq) => stream.get_module(Iq.Module.IDENTITY).send_iq(stream, iq);
-        if (state != PENDING || action != "session-accept") {
-            return;
-        }
-        StanzaNode? content = jingle.get_subnode("content");
-        if (content == null) {
-            // TODO(hrxi): here and below, should we terminate the session?
-            send_iq(new Iq.Stanza.error(iq, new ErrorStanza.bad_request("no content element")));
-            return;
+    public void handle_iq_set(XmppStream stream, string action, StanzaNode jingle, Iq.Stanza iq) throws IqError {
+        switch (action) {
+            case "session-accept":
+                if (state != INITIATE_SENT) {
+                    throw new IqError.OUT_OF_ORDER("got session-accept while not waiting for one");
+                }
+                handle_session_accept(stream, jingle, iq);
+                break;
+            case "session-terminate":
+                handle_session_terminate(stream, jingle, iq);
+                break;
+            case "content-accept":
+            case "content-add":
+            case "content-modify":
+            case "content-reject":
+            case "content-remove":
+            case "security-info":
+            case "transport-accept":
+            case "transport-info":
+            case "transport-reject":
+            case "transport-replace":
+                throw new IqError.NOT_IMPLEMENTED(@"$(action) is not implemented");
+            default:
+                throw new IqError.BAD_REQUEST("invalid action");
         }
+    }
+    void handle_session_accept(XmppStream stream, StanzaNode jingle, Iq.Stanza iq) throws IqError {
         string? responder_str = jingle.get_attribute("responder");
         Jid responder;
         if (responder_str != null) {
@@ -190,38 +372,64 @@ public class Session {
             // TODO(hrxi): more sanity checking, perhaps replace who we're talking to
         }
         if (!responder.is_full()) {
-            send_iq(new Iq.Stanza.error(iq, new ErrorStanza.bad_request("invalid responder JID")));
-            return;
+            throw new IqError.BAD_REQUEST("invalid responder JID");
         }
-        try {
-            conn = stream.get_flag(Flag.IDENTITY).create_connection(stream, type_, peer_full_jid, content);
-        } catch (CreateConnectionError e) {
-            if (e is CreateConnectionError.BAD_REQUEST) {
-                send_iq(new Iq.Stanza.error(iq, new ErrorStanza.bad_request(e.message)));
-            } else if (e is CreateConnectionError.NOT_ACCEPTABLE) {
-                send_iq(new Iq.Stanza.error(iq, new ErrorStanza.not_acceptable(e.message)));
-            }
-            return;
+        Gee.List<StanzaNode> contents = jingle.get_subnodes("content");
+        if (contents.size == 0) {
+            // TODO(hrxi): here and below, should we terminate the session?
+            throw new IqError.BAD_REQUEST("missing content node");
         }
-        send_iq(new Iq.Stanza.result(iq));
-        if (conn == null) {
-            terminate(stream, new StanzaNode.build("reason", NS_URI)
-                .put_node(new StanzaNode.build("unsupported-transports", NS_URI)));
-            return;
+        if (contents.size > 1) {
+            throw new IqError.NOT_IMPLEMENTED("can't process multiple content nodes");
+        }
+        StanzaNode content = contents[0];
+        StanzaNode description = get_single_node_anyns(content, "description");
+        StanzaNode transport_node = get_single_node_anyns(content, "transport");
+        if (transport_node.ns_uri != transport.transport_ns_uri()) {
+            throw new IqError.BAD_REQUEST("session-accept with unnegotiated transport method");
         }
-        conn.on_error.connect((stream, error) => on_error(stream, error));
-        conn.on_data.connect((stream, data) => on_data(stream, data));
-        conn.on_ready.connect((stream) => on_ready(stream));
-        on_error.connect((stream, error) => handle_error(stream, error));
-        conn.connect(stream);
+        transport.update_transport(transport_node);
+        conn = transport.create_transport_connection(stream, peer_full_jid, Role.INITIATOR);
+        transport = null;
+        stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.result(iq));
         state = ACTIVE;
+        accepted(stream);
+    }
+    void handle_session_terminate(XmppStream stream, StanzaNode jingle, Iq.Stanza iq) throws IqError {
+        stream.get_module(Iq.Module.IDENTITY).send_iq(stream, new Iq.Stanza.result(iq));
+        // TODO(hrxi): also handle presence type=unavailable
     }
 
-    public void send(XmppStream stream, uint8[] data) {
-        if (state != ACTIVE) {
+    public void accept(XmppStream stream, StanzaNode description) {
+        if (state != INITIATE_RECEIVED) {
+            return; // TODO(hrxi): what to do?
+        }
+        StanzaNode jingle = new StanzaNode.build("jingle", NS_URI)
+            .add_self_xmlns()
+            .put_attribute("action", "session-accept")
+            .put_attribute("sid", sid)
+            .put_node(new StanzaNode.build("content", NS_URI)
+                .put_attribute("creator", "initiator")
+                .put_attribute("name", content_name)
+                .put_node(description)
+                .put_node(transport.to_transport_stanza_node())
+            );
+        Iq.Stanza iq = new Iq.Stanza.set(jingle) { to=peer_full_jid };
+        stream.get_module(Iq.Module.IDENTITY).send_iq(stream, iq);
+
+        conn = transport.create_transport_connection(stream, peer_full_jid, Role.RESPONDER);
+        transport = null;
+
+        state = ACTIVE;
+    }
+
+    public void reject(XmppStream stream) {
+        if (state != INITIATE_RECEIVED) {
             return; // TODO(hrxi): what to do?
         }
-        conn.send(stream, data);
+        StanzaNode reason = new StanzaNode.build("reason", NS_URI)
+            .put_node(new StanzaNode.build("decline", NS_URI));
+        terminate(stream, reason);
     }
 
     public void set_application_error(XmppStream stream, StanzaNode? application_reason = null) {
@@ -237,16 +445,16 @@ public class Session {
         if (state != ACTIVE) {
             return; // TODO(hrxi): what to do?
         }
-        conn.close(stream);
+        conn.close();
     }
 
     public void terminate(XmppStream stream, StanzaNode reason) {
-        if (state != PENDING && state != ACTIVE) {
+        if (state != INITIATE_SENT && state != INITIATE_RECEIVED && state != ACTIVE) {
             // TODO(hrxi): what to do?
             return;
         }
-        if (conn != null) {
-            conn.close(stream);
+        if (state == ACTIVE) {
+            conn.close();
         }
 
         StanzaNode jingle = new StanzaNode.build("jingle", NS_URI)
@@ -264,56 +472,14 @@ public class Session {
     }
 }
 
-public abstract class Connection {
-    public Jid? peer_full_jid { get; private set; }
-
-    public Connection(Jid peer_full_jid) {
-        this.peer_full_jid = peer_full_jid;
-    }
-
-    public signal void on_error(XmppStream stream, Error error);
-    public signal void on_data(XmppStream stream, uint8[] data);
-    public signal void on_ready(XmppStream stream);
-
-    public abstract void connect(XmppStream stream);
-    public abstract void send(XmppStream stream, uint8[] data);
-    public abstract void close(XmppStream stream);
-}
-
 public class Flag : XmppStreamFlag {
     public static FlagIdentity<Flag> IDENTITY = new FlagIdentity<Flag>(NS_URI, "jingle");
 
-    private Gee.List<Transport> transports = new ArrayList<Transport>();
     private HashMap<string, Session> sessions = new HashMap<string, Session>();
 
-    public void add_transport(Transport transport) { transports.add(transport); }
-    public Transport? select_transport(XmppStream stream, TransportType type, Jid receiver_full_jid) {
-        foreach (Transport transport in transports) {
-            if (transport.transport_type() != type) {
-                continue;
-            }
-            // TODO(hrxi): prioritization
-            if (transport.is_transport_available(stream, receiver_full_jid)) {
-                return transport;
-            }
-        }
-        return null;
-    }
     public void add_session(Session session) {
         sessions[session.sid] = session;
     }
-    public Connection? create_connection(XmppStream stream, Type type, Jid peer_full_jid, StanzaNode content) throws CreateConnectionError {
-        foreach (Transport transport in transports) {
-            if (transport.transport_type() != type) {
-                continue;
-            }
-            Connection? conn = transport.create_transport_connection(stream, peer_full_jid, content);
-            if (conn != null) {
-                return conn;
-            }
-        }
-        return null;
-    }
     public Session? get_session(string sid) {
         return sessions.has_key(sid) ? sessions[sid] : null;
     }
diff --git a/xmpp-vala/src/module/xep/0234_jingle_file_transfer.vala b/xmpp-vala/src/module/xep/0234_jingle_file_transfer.vala
index cd249017..57222bae 100644
--- a/xmpp-vala/src/module/xep/0234_jingle_file_transfer.vala
+++ b/xmpp-vala/src/module/xep/0234_jingle_file_transfer.vala
@@ -6,19 +6,27 @@ namespace Xmpp.Xep.JingleFileTransfer {
 
 private const string NS_URI = "urn:xmpp:jingle:apps:file-transfer:5";
 
-public errordomain Error {
-    FILE_INACCESSIBLE,
-}
-
-public class Module : XmppStreamModule {
+public class Module : Jingle.ContentType, XmppStreamModule {
     public static Xmpp.ModuleIdentity<Module> IDENTITY = new Xmpp.ModuleIdentity<Module>(NS_URI, "0234_jingle_file_transfer");
 
     public override void attach(XmppStream stream) {
-        stream.add_flag(new Flag());
         stream.get_module(ServiceDiscovery.Module.IDENTITY).add_feature(stream, NS_URI);
+        stream.get_module(Jingle.Module.IDENTITY).register_content_type(this);
     }
     public override void detach(XmppStream stream) { }
 
+    public string content_type_ns_uri() {
+        return NS_URI;
+    }
+    public Jingle.TransportType content_type_transport_type() {
+        return Jingle.TransportType.STREAMING;
+    }
+    public Jingle.ContentParameters parse_content_parameters(StanzaNode description) throws Jingle.IqError {
+        return Parameters.parse(this, description);
+    }
+
+    public signal void file_incoming(XmppStream stream, FileTransfer file_transfer);
+
     public bool is_available(XmppStream stream, Jid full_jid) {
         bool? has_feature = stream.get_flag(ServiceDiscovery.Flag.IDENTITY).has_entity_feature(full_jid, NS_URI);
         if (has_feature == null || !(!)has_feature) {
@@ -27,25 +35,7 @@ public class Module : XmppStreamModule {
         return stream.get_module(Jingle.Module.IDENTITY).is_available(stream, Jingle.TransportType.STREAMING, full_jid);
     }
 
-    public void offer_file(XmppStream stream, Jid receiver_full_jid, string path) throws Error {
-        File file = File.new_for_path(path);
-        FileInputStream input_stream;
-        int64 size;
-        try {
-            input_stream = file.read();
-        } catch (GLib.Error e) {
-            throw new Error.FILE_INACCESSIBLE(@"could not open the file \"$path\" for reading: $(e.message)");
-        }
-        try {
-            size = input_stream.query_info(FileAttribute.STANDARD_SIZE).get_size();
-        } catch (GLib.Error e) {
-            throw new Error.FILE_INACCESSIBLE(@"could not read the size: $(e.message)");
-        }
-
-        offer_file_stream(stream, receiver_full_jid, input_stream, file.get_basename(), size);
-    }
-
-    public void offer_file_stream(XmppStream stream, Jid receiver_full_jid, InputStream input_stream, string basename, int64 size) {
+    public async void offer_file_stream(XmppStream stream, Jid receiver_full_jid, InputStream input_stream, string basename, int64 size) throws IOError {
         StanzaNode description = new StanzaNode.build("description", NS_URI)
             .add_self_xmlns()
             .put_node(new StanzaNode.build("file", NS_URI)
@@ -53,48 +43,88 @@ public class Module : XmppStreamModule {
                 .put_node(new StanzaNode.build("size", NS_URI).put_node(new StanzaNode.text(size.to_string()))));
                 // TODO(hrxi): Add the mandatory hash field
 
-        Jingle.Session? session = stream.get_module(Jingle.Module.IDENTITY)
+        Jingle.Session session = stream.get_module(Jingle.Module.IDENTITY)
             .create_session(stream, Jingle.TransportType.STREAMING, receiver_full_jid, Jingle.Senders.INITIATOR, "a-file-offer", description); // TODO(hrxi): Why "a-file-offer"?
 
-        FileTransfer transfer = new FileTransfer(input_stream);
-        session.on_ready.connect(transfer.send_data);
-        stream.get_flag(Flag.IDENTITY).add_file_transfer(transfer);
+        SourceFunc callback = offer_file_stream.callback;
+        session.accepted.connect((stream) => {
+            session.conn.input_stream.close();
+            Idle.add((owned) callback);
+        });
+        yield;
+
+        // TODO(hrxi): catch errors
+        yield session.conn.output_stream.splice_async(input_stream, OutputStreamSpliceFlags.CLOSE_SOURCE|OutputStreamSpliceFlags.CLOSE_TARGET);
     }
 
     public override string get_ns() { return NS_URI; }
     public override string get_id() { return IDENTITY.id; }
 }
 
-public class FileTransfer : Object {
-    InputStream input_stream;
-    public FileTransfer(InputStream input_stream) {
-        this.input_stream = input_stream;
+public class Parameters : Jingle.ContentParameters, Object {
+    Module parent;
+    string? media_type;
+    public string? name { get; private set; }
+    public int64 size { get; private set; }
+    public StanzaNode original_description { get; private set; }
+    public Parameters(Module parent, StanzaNode original_description, string? media_type, string? name, int64? size) {
+        this.parent = parent;
+        this.original_description = original_description;
+        this.media_type = media_type;
+        this.name = name;
+        this.size = size;
     }
-    public void send_data(Jingle.Session session, XmppStream stream) {
-        uint8 buffer[4096];
-        ssize_t read;
-        try {
-            if((read = input_stream.read(buffer)) != 0) {
-                session.send(stream, buffer[0:read]);
-            } else {
-                session.close_connection(stream);
+    public static Parameters parse(Module parent, StanzaNode description) throws Jingle.IqError {
+        Gee.List<StanzaNode> files = description.get_subnodes("file", NS_URI);
+        if (files.size != 1) {
+            throw new Jingle.IqError.BAD_REQUEST("there needs to be exactly one file node");
+        }
+        StanzaNode file = files[0];
+        StanzaNode? media_type_node = file.get_subnode("media-type", NS_URI);
+        StanzaNode? name_node = file.get_subnode("name", NS_URI);
+        StanzaNode? size_node = file.get_subnode("size", NS_URI);
+        string? media_type = media_type_node != null ? media_type_node.get_string_content() : null;
+        string? name = name_node != null ? name_node.get_string_content() : null;
+        string? size_raw = size_node != null ? size_node.get_string_content() : null;
+        // TODO(hrxi): For some reason, the ?:-expression does not work due to a type error.
+        //int64? size = size_raw != null ? int64.parse(size_raw) : null; // TODO(hrxi): this has no error handling
+        int64 size = -1;
+        if (size_raw != null) {
+            size = int64.parse(size_raw);
+            if (size < 0) {
+                throw new Jingle.IqError.BAD_REQUEST("negative file size is invalid");
             }
-        } catch (GLib.IOError e) {
-            session.set_application_error(stream);
         }
-        // TODO(hrxi): remove file transfer
+
+        return new Parameters(parent, description, media_type, name, size);
+    }
+    void on_session_initiate(XmppStream stream, Jingle.Session session) {
+        parent.file_incoming(stream, new FileTransfer(session, this));
     }
 }
 
-public class Flag : XmppStreamFlag {
-    public static FlagIdentity<Flag> IDENTITY = new FlagIdentity<Flag>(NS_URI, "jingle_file_transfer");
+public class FileTransfer : Object {
+    Jingle.Session session;
+    Parameters parameters;
+
+    public Jid peer { get { return session.peer_full_jid; } }
+    public string? file_name { get { return parameters.name; } }
+    public int64 size { get { return parameters.size; } }
 
-    private Gee.List<FileTransfer> transfers = new ArrayList<FileTransfer>();
+    public InputStream? stream { get { return session.conn != null ? session.conn.input_stream : null; } }
 
-    public void add_file_transfer(FileTransfer transfer) { transfers.add(transfer); }
+    public FileTransfer(Jingle.Session session, Parameters parameters) {
+        this.session = session;
+        this.parameters = parameters;
+    }
 
-    public override string get_ns() { return NS_URI; }
-    public override string get_id() { return IDENTITY.id; }
+    public void accept(XmppStream stream) {
+        session.accept(stream, parameters.original_description);
+        session.conn.output_stream.close();
+    }
+    public void reject(XmppStream stream) {
+        session.reject(stream);
+    }
 }
 
 }
diff --git a/xmpp-vala/src/module/xep/0261_jingle_in_band_bytestreams.vala b/xmpp-vala/src/module/xep/0261_jingle_in_band_bytestreams.vala
index 57dbaaa3..dc2e8d7c 100644
--- a/xmpp-vala/src/module/xep/0261_jingle_in_band_bytestreams.vala
+++ b/xmpp-vala/src/module/xep/0261_jingle_in_band_bytestreams.vala
@@ -5,12 +5,13 @@ namespace Xmpp.Xep.JingleInBandBytestreams {
 
 private const string NS_URI = "urn:xmpp:jingle:transports:ibb:1";
 private const int DEFAULT_BLOCKSIZE = 4096;
+private const int MAX_BLOCKSIZE = 65535;
 
 public class Module : Jingle.Transport, XmppStreamModule {
     public static Xmpp.ModuleIdentity<Module> IDENTITY = new Xmpp.ModuleIdentity<Module>(NS_URI, "0261_jingle_in_band_bytestreams");
 
     public override void attach(XmppStream stream) {
-        stream.get_module(Jingle.Module.IDENTITY).add_transport(stream, this);
+        stream.get_module(Jingle.Module.IDENTITY).register_transport(this);
         stream.get_module(ServiceDiscovery.Module.IDENTITY).add_feature(stream, NS_URI);
     }
     public override void detach(XmppStream stream) { }
@@ -23,52 +24,53 @@ public class Module : Jingle.Transport, XmppStreamModule {
         return result != null && result;
     }
 
+    public string transport_ns_uri() {
+        return NS_URI;
+    }
     public Jingle.TransportType transport_type() {
         return Jingle.TransportType.STREAMING;
     }
-    public StanzaNode to_transport_stanza_node() {
-        return new StanzaNode.build("transport", NS_URI)
-            .add_self_xmlns()
-            .put_attribute("block-size", DEFAULT_BLOCKSIZE.to_string())
-            .put_attribute("sid", random_uuid());
+    public Jingle.TransportParameters create_transport_parameters() {
+        return new Parameters(random_uuid(), DEFAULT_BLOCKSIZE);
+    }
+    public Jingle.TransportParameters parse_transport_parameters(StanzaNode transport) throws Jingle.IqError {
+        return Parameters.parse(transport);
     }
+}
 
-    public Jingle.Connection? create_transport_connection(XmppStream stream, Jid peer_full_jid, StanzaNode content) throws Jingle.CreateConnectionError {
-        StanzaNode? transport = content.get_subnode("transport", NS_URI);
-        if (transport == null) {
-            return null;
-        }
+class Parameters : Jingle.TransportParameters, Object {
+    public string sid { get; private set; }
+    public int block_size { get; private set; }
+    public Parameters(string sid, int block_size) {
+        this.sid = sid;
+        this.block_size = block_size;
+    }
+    public static Parameters parse(StanzaNode transport) throws Jingle.IqError {
         string? sid = transport.get_attribute("sid");
         int block_size = transport.get_attribute_int("block-size");
-        if (sid == null || block_size <= 0) {
-            throw new Jingle.CreateConnectionError.BAD_REQUEST("Invalid IBB parameters");
-        }
-        if (block_size > DEFAULT_BLOCKSIZE) {
-            throw new Jingle.CreateConnectionError.NOT_ACCEPTABLE("Invalid IBB parameters: peer increased block size");
+        if (sid == null || block_size <= 0 || block_size > MAX_BLOCKSIZE) {
+            throw new Jingle.IqError.BAD_REQUEST("missing or invalid sid or blocksize");
         }
-        return new Connection(peer_full_jid, new InBandBytestreams.Connection(peer_full_jid, sid, block_size));
+        return new Parameters(sid, block_size);
     }
-}
-
-public class Connection : Jingle.Connection {
-    InBandBytestreams.Connection inner;
-
-    public Connection(Jid full_jid, InBandBytestreams.Connection inner) {
-        base(full_jid);
-        inner.on_error.connect((stream, error) => on_error(stream, new Jingle.Error.TRANSPORT_ERROR(error)));
-        inner.on_data.connect((stream, data) => on_data(stream, data));
-        inner.on_ready.connect((stream) => on_ready(stream));
-        this.inner = inner;
+    public string transport_ns_uri() {
+        return NS_URI;
     }
-
-    public override void connect(XmppStream stream) {
-        inner.connect(stream);
+    public StanzaNode to_transport_stanza_node() {
+        return new StanzaNode.build("transport", NS_URI)
+            .add_self_xmlns()
+            .put_attribute("block-size", block_size.to_string())
+            .put_attribute("sid", sid);
     }
-    public override void send(XmppStream stream, uint8[] data) {
-        inner.send(stream, data);
+    public void update_transport(StanzaNode transport) throws Jingle.IqError {
+        Parameters other = Parameters.parse(transport);
+        if (other.sid != sid || other.block_size > block_size) {
+            throw new Jingle.IqError.NOT_ACCEPTABLE("invalid IBB sid or block_size");
+        }
+        block_size = other.block_size;
     }
-    public override void close(XmppStream stream) {
-        inner.close(stream);
+    public IOStream create_transport_connection(XmppStream stream, Jid peer_full_jid, Jingle.Role role) {
+        return InBandBytestreams.Connection.create(stream, peer_full_jid, sid, block_size, role == Jingle.Role.INITIATOR);
     }
 }