vendor: add j-keck/arping

vendor/github.com/j-keck/arping/arping_linux.go

@@ -0,0 +1,38 @@
+package arping
+
+import (
+	"net"
+	"syscall"
+	"time"
+)
+
+var sock int
+var toSockaddr syscall.SockaddrLinklayer
+
+func initialize(iface net.Interface) error {
+	toSockaddr = syscall.SockaddrLinklayer{Ifindex: iface.Index}
+
+	// 1544 = htons(ETH_P_ARP)
+	const proto = 1544
+	var err error
+	sock, err = syscall.Socket(syscall.AF_PACKET, syscall.SOCK_RAW, proto)
+	return err
+}
+
+func send(request arpDatagram) (time.Time, error) {
+	return time.Now(), syscall.Sendto(sock, request.MarshalWithEthernetHeader(), 0, &toSockaddr)
+}
+
+func receive() (arpDatagram, time.Time, error) {
+	buffer := make([]byte, 128)
+	n, _, err := syscall.Recvfrom(sock, buffer, 0)
+	if err != nil {
+		return arpDatagram{}, time.Now(), err
+	}
+	// skip 14 bytes ethernet header
+	return parseArpDatagram(buffer[14:n]), time.Now(), nil
+}
+
+func deinitialize() error {
+	return syscall.Close(sock)
+}