76 lines
1.5 KiB
Go
76 lines
1.5 KiB
Go
package node
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import (
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"encoding/binary"
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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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)
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func localBroadcaster() {
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var (
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buf1 = make([]byte, bufferSize)
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buf2 = make([]byte, bufferSize)
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)
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time.Sleep(4 * time.Second)
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doBroadcast(buf1, buf2)
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for range time.Tick(32 * time.Second) {
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doBroadcast(buf1, buf2)
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}
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}
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func doBroadcast(buf1, buf2 []byte) {
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ifaces, err := net.Interfaces()
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if err != nil {
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log.Printf("Failed to list interfaces: %v", err)
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return
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}
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for _, iface := range ifaces {
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if iface.Flags&net.FlagUp == 0 || iface.Flags&net.FlagRunning == 0 {
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continue
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}
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if iface.Flags&net.FlagPointToPoint != 0 {
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continue
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}
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if iface.Flags&net.FlagBroadcast == 0 {
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continue
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}
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addrs, err := iface.Addrs()
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if err != nil {
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log.Printf("Failed to get interface addresses: %v", err)
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continue
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}
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for _, addr := range addrs {
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ipNet, ok := addr.(*net.IPNet)
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if !ok {
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continue
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}
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ip4 := ipNet.IP.To4()
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if ip4 == nil {
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continue
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}
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ip, ok := lastAddr(ipNet)
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if !ok {
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log.Printf("Failed to find broadcast address: %v", ipNet)
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continue
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}
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log.Printf("Broadcasting on address: %v", ip)
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//addr := netip.AddrPortFrom(ip, 456)
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}
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}
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}
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// works when the n is a prefix, otherwise...
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func lastAddr(n *net.IPNet) (netip.Addr, bool) {
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ip := make(net.IP, len(n.IP.To4()))
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binary.BigEndian.PutUint32(ip, binary.BigEndian.Uint32(n.IP.To4())|
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^binary.BigEndian.Uint32(net.IP(n.Mask).To4()))
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return netip.AddrFromSlice(ip)
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}
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