90 lines
1.5 KiB
Go
90 lines
1.5 KiB
Go
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package tendrils
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import (
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"net"
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"time"
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"golang.org/x/net/icmp"
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"golang.org/x/net/ipv4"
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)
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func (t *Tendrils) pingNode(node *Node) {
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t.nodes.mu.RLock()
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var ips []string
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for _, iface := range node.Interfaces {
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for ipStr := range iface.IPs {
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ip := net.ParseIP(ipStr)
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if ip != nil && ip.To4() != nil {
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ips = append(ips, ipStr)
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}
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}
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}
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t.nodes.mu.RUnlock()
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if len(ips) == 0 {
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return
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}
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for _, ipStr := range ips {
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reachable := t.pingIP(ipStr)
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if reachable {
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t.errors.ClearUnreachable(node, ipStr)
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} else {
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t.errors.SetUnreachable(node, ipStr)
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}
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}
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}
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func (t *Tendrils) pingIP(ipStr string) bool {
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conn, err := icmp.ListenPacket("ip4:icmp", "0.0.0.0")
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if err != nil {
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return false
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}
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defer conn.Close()
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conn.SetDeadline(time.Now().Add(500 * time.Millisecond))
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ip := net.ParseIP(ipStr)
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seq := uint16(time.Now().UnixNano() & 0xFFFF)
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msg := icmp.Message{
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Type: ipv4.ICMPTypeEcho,
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Code: 0,
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Body: &icmp.Echo{
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ID: int(seq),
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Seq: 1,
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Data: []byte("tendrils"),
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},
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}
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msgBytes, err := msg.Marshal(nil)
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if err != nil {
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return false
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}
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_, err = conn.WriteTo(msgBytes, &net.IPAddr{IP: ip})
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if err != nil {
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return false
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}
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buf := make([]byte, 1500)
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for {
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n, peer, err := conn.ReadFrom(buf)
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if err != nil {
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return false
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}
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parsed, err := icmp.ParseMessage(1, buf[:n])
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if err != nil {
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continue
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}
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if parsed.Type == ipv4.ICMPTypeEchoReply {
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if ipAddr, ok := peer.(*net.IPAddr); ok {
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if ipAddr.IP.String() == ipStr {
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return true
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}
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}
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}
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}
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}
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