init

pinger.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"errors"
+	"net"
+	"time"
+
+	"github.com/miekg/dns"
+	probing "github.com/prometheus-community/pro-bing"
+)
+
+type PingResult struct {
+	RTT   time.Duration
+	Alive bool
+	Err   error
+	IP    string
+}
+
+type PingOptions struct {
+	Timeout     time.Duration
+	Size        int
+	DisableIPv6 bool
+	DNSServer   string
+}
+
+func resolveWithCustomDNS(server, host string) (string, error) {
+	c := new(dns.Client)
+	m := new(dns.Msg)
+	m.SetQuestion(dns.Fqdn(host), dns.TypeA)
+
+	resp, _, err := c.Exchange(m, server)
+	if err != nil {
+		return "", err
+	}
+
+	for _, ans := range resp.Answer {
+		if a, ok := ans.(*dns.A); ok {
+			return a.A.String(), nil
+		}
+	}
+
+	return "", errors.New("no A record found")
+}
+
+func resolveHost(host, dnsServer string, disableIPv6 bool) (string, error) {
+	if ip := net.ParseIP(host); ip != nil {
+		return host, nil
+	}
+
+	if dnsServer != "" {
+		if _, _, err := net.SplitHostPort(dnsServer); err != nil {
+			dnsServer = net.JoinHostPort(dnsServer, "53")
+		}
+		return resolveWithCustomDNS(dnsServer, host)
+	}
+
+	if disableIPv6 {
+		ips, err := net.LookupIP(host)
+		if err != nil {
+			return "", err
+		}
+		for _, ip := range ips {
+			if ip.To4() != nil {
+				return ip.String(), nil
+			}
+		}
+		return "", errors.New("no IPv4 address found")
+	}
+
+	ip, err := net.ResolveIPAddr("ip", host)
+	if err != nil {
+		return "", err
+	}
+	return ip.IP.String(), nil
+}
+
+func doPing(host string, opts PingOptions) PingResult {
+	ip, err := resolveHost(host, opts.DNSServer, opts.DisableIPv6)
+	if err != nil {
+		return PingResult{Alive: false, Err: err}
+	}
+
+	pinger, err := probing.NewPinger(ip)
+	if err != nil {
+		return PingResult{Alive: false, Err: err, IP: ip}
+	}
+
+	if opts.DisableIPv6 {
+		pinger.SetNetwork("ip4")
+	}
+
+	pinger.Count = 1
+	pinger.Timeout = opts.Timeout
+	pinger.Size = opts.Size
+
+	// falls du im Container kein CAP_NET_RAW gibst:
+	pinger.SetPrivileged(false) // oder aus Config
+	// wenn du CAP_NET_RAW vergibst:
+	// pinger.SetPrivileged(true)
+
+	if err := pinger.Run(); err != nil {
+		return PingResult{Alive: false, Err: err, IP: ip}
+	}
+
+	stats := pinger.Statistics()
+	if stats.PacketsRecv < 1 {
+		return PingResult{Alive: false, Err: errors.New("no reply"), IP: ip}
+	}
+
+	return PingResult{
+		RTT:   stats.AvgRtt,
+		Alive: true,
+		IP:    ip,
+	}
+
+}