60 lines
1.2 KiB
Go
60 lines
1.2 KiB
Go
package multicast
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import (
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"log"
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"net"
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"net/netip"
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"time"
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"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
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)
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func Broadcast(
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selfVPNIP netip.Addr,
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pubKey wgtypes.Key,
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wgPort uint16,
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signKey *[64]byte,
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) {
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for {
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broadcastInner(selfVPNIP, pubKey, wgPort, signKey)
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time.Sleep(errorTimeout)
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}
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}
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func broadcastInner(selfVPNIP netip.Addr, pubKey wgtypes.Key, wgPort uint16, signKey *[64]byte) {
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addr := multicastAddr(selfVPNIP)
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conn, err := net.ListenMulticastUDP("udp", nil, addr)
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if err != nil {
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log.Printf("[MCBroadcast] bind: %v", err)
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return
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}
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defer conn.Close()
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buf := make([]byte, BufferSize)
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packet := Packet{
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PeerIP: selfVPNIP.As4()[3],
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WGPubKey: pubKey,
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WGPort: wgPort,
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}
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// Re-sign on each send so the timestamp is fresh; a stale timestamp would be
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// dropped by receivers' freshness gate.
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send := func() error {
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packet.Timestamp = time.Now().Unix()
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payload := packet.marshal(buf, signKey)
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_, err := conn.WriteToUDP(payload, addr)
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return err
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}
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if err := send(); err != nil {
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log.Printf("[MCBroadcast] write: %v", err)
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}
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for range time.Tick(broadcastInterval) {
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if err := send(); err != nil {
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log.Printf("[MCBroadcast] write: %v", err)
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return
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}
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}
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}
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