67 lines
1.4 KiB
Go
67 lines
1.4 KiB
Go
package peer
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import (
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"encoding/binary"
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"fmt"
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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 RunMCReader(g Globals, hp *HolePunch, netName string) {
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for {
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if err := runMCReaderInner(g, hp, netName); err != nil {
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log.Printf("[MCReader] %v", err)
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}
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time.Sleep(broadcastErrorTimeoutInterval)
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}
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}
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func runMCReaderInner(g Globals, hp *HolePunch, netName string) error {
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conn, err := net.ListenMulticastUDP("udp", nil, multicastAddr)
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if err != nil {
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return fmt.Errorf("bind: %w", err)
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}
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defer conn.Close()
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buf := make([]byte, 64)
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for {
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conn.SetReadDeadline(time.Now().Add(32 * time.Second))
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n, src, err := conn.ReadFromUDPAddrPort(buf)
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if err != nil {
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return fmt.Errorf("read: %w", err)
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}
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if n != beaconLen {
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continue
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}
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handleBeacon(g, hp, netName, buf[:n], src)
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}
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}
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func handleBeacon(g Globals, hp *HolePunch, netName string, beacon []byte, src netip.AddrPort) {
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peerIPByte := beacon[0]
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if peerIPByte == g.LocalPeerIP {
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return
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}
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pubKey, err := wgtypes.NewKey(beacon[1:33])
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if err != nil {
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return
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}
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// Skip relay peers: probing would replace their /24 AllowedIPs with empty.
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if state, err := loadNetworkState(netName); err == nil {
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if p := state.Peers[peerIPByte]; p != nil && p.Relay {
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return
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}
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}
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wgPort := binary.BigEndian.Uint16(beacon[33:35])
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endpoint := netip.AddrPortFrom(src.Addr().Unmap(), wgPort)
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hp.OnEndpointLearned(peerIPByte, pubKey, endpoint, false)
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}
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