J. David Lee
1d3cc1f959
Co-authored-by: jdl <jdl@desktop> Co-authored-by: jdl <jdl@crumpington.com> Reviewed-on: #3
71 lines
1.4 KiB
Go
71 lines
1.4 KiB
Go
package peer
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import (
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"log"
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"net"
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"sync/atomic"
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"time"
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)
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func runMCReader(
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rt *atomic.Pointer[routingTable],
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handleControlMsg func(destIP byte, msg any),
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) {
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for {
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runMCReaderInner(rt, handleControlMsg)
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time.Sleep(broadcastErrorTimeoutInterval)
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}
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}
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func runMCReaderInner(
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rt *atomic.Pointer[routingTable],
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handleControlMsg func(destIP byte, msg any),
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) {
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var (
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raw = newBuf()
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buf = newBuf()
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logf = func(s string, args ...any) {
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log.Printf("[MCReader] "+s, args...)
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}
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)
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conn, err := net.ListenMulticastUDP("udp", nil, multicastAddr)
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if err != nil {
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logf("Failed to bind to multicast address: %v", err)
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return
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}
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for {
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conn.SetReadDeadline(time.Now().Add(32 * time.Second))
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n, remoteAddr, err := conn.ReadFromUDPAddrPort(raw[:bufferSize])
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if err != nil {
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logf("Failed to read from UDP port): %v", err)
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return
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}
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raw = raw[:n]
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h, ok := headerFromLocalDiscoveryPacket(raw)
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if !ok {
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logf("Failed to open discovery packet?")
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continue
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}
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peer := rt.Load().Peers[h.SourceIP]
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if peer.PubSignKey == nil {
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logf("No signing key for peer %d.", h.SourceIP)
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continue
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}
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if !verifyLocalDiscoveryPacket(raw, buf, peer.PubSignKey) {
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logf("Invalid signature from peer: %d", h.SourceIP)
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continue
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}
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msg := controlMsg[packetLocalDiscovery]{
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SrcIP: h.SourceIP,
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SrcAddr: remoteAddr,
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}
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handleControlMsg(h.SourceIP, msg)
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}
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}
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