discovery: self announce

Signed-off-by: Maciek Borzecki <maciek.borzecki@gmail.com>

discovery/announce.go

@@ -0,0 +1,45 @@
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//        http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+package discovery
+
+import (
+	"context"
+	"net"
+
+	"github.com/pkg/errors"
+
+	"github.com/bboozzoo/mconnect/protocol/packet"
+)
+
+func Announce(ctx context.Context, identity packet.Identity) error {
+	p := packet.New("kdeconnect.identity", identity)
+	data, err := packet.Marshal(p)
+	if err != nil {
+		return errors.Wrapf(err, "failed to marshal packet")
+	}
+
+	addr := net.UDPAddr{
+		Port: 1716,
+		IP:   net.ParseIP("255.255.255.255"),
+	}
+	c, err := net.DialUDP("udp", nil, &addr)
+	if err != nil {
+		return errors.Wrapf(err, "failed to open UDP socket")
+	}
+	defer c.Close()
+
+	_, err = c.Write(data)
+	if err != nil {
+		return errors.Wrapf(err, "failed to send identity packet")
+	}
+	return nil
+}