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80 lines
2.1 KiB
80 lines
2.1 KiB
// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package discovery
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import (
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"context"
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"net"
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"github.com/pkg/errors"
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"github.com/bboozzoo/mconnect/logger"
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"github.com/bboozzoo/mconnect/protocol/packet"
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)
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type Listener struct {
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conn *net.UDPConn
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}
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func NewListener() (*Listener, error) {
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addr := net.UDPAddr{
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Port: 1716,
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}
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conn, err := net.ListenUDP("udp", &addr)
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if err != nil {
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return nil, err
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}
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listener := &Listener{
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conn: conn,
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}
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return listener, nil
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}
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// Discovery conveys the received discovery information
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type Discovery struct {
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// Packet is the original packet received
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Packet *packet.Packet
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// Identity is the parsed identity data
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Identity *packet.Identity
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// From is the address the packet was received from
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From *net.UDPAddr
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}
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// Receive blocks waiting to receive a discovery packet. Once received, it will
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// parse the packet and return a result.
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func (l *Listener) Receive(ctx context.Context) (*Discovery, error) {
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log := logger.FromContext(ctx)
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buf := make([]byte, 4096)
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count, addr, err := l.conn.ReadFromUDP(buf)
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if err != nil {
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return nil, errors.Wrap(err, "failed to receive a packet")
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}
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log.Debugf("got %v bytes from %v", count, addr)
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log.Debugf("data:\n%s", string(buf))
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var p packet.Packet
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if err := packet.Unmarshal(buf, &p); err != nil {
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return nil, errors.Wrap(err, "failed to parse packet")
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}
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identity, err := p.AsIdentity()
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if err != nil {
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return nil, errors.Wrap(err, "failed to parse as identity packet")
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}
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discovery := &Discovery{
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Packet: &p,
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Identity: identity,
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From: addr,
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}
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return discovery, nil
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}
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