Initial commit after restructure

network/environment/location.go

@@ -0,0 +1,115 @@
+// Copyright Safing ICS Technologies GmbH. Use of this source code is governed by the AGPL license that can be found in the LICENSE file.
+
+package environment
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"github.com/Safing/safing-core/network/netutils"
+	"time"
+
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv4"
+)
+
+// TODO: reference forking
+// TODO: Create IPv6 version of GetApproximateInternetLocation
+
+// GetApproximateInternetLocation returns the IP-address of the nearest ping-answering internet node
+func GetApproximateInternetLocation() (net.IP, error) {
+	// TODO: first check if we have a public IP
+	// net.InterfaceAddrs()
+
+	// Traceroute example
+
+	var dst net.IPAddr
+	dst.IP = net.IPv4(8, 8, 8, 8)
+
+	c, err := net.ListenPacket("ip4:1", "0.0.0.0") // ICMP for IPv4
+	if err != nil {
+		return nil, err
+	}
+	defer c.Close()
+
+	p := ipv4.NewPacketConn(c)
+	err = p.SetControlMessage(ipv4.FlagTTL|ipv4.FlagSrc|ipv4.FlagDst|ipv4.FlagInterface, true)
+	if err != nil {
+		return nil, err
+	}
+
+	wm := icmp.Message{
+		Type: ipv4.ICMPTypeEcho, Code: 0,
+		Body: &icmp.Echo{
+			ID: os.Getpid() & 0xffff,
+			// TODO: think of something better and not suspicious
+			Data: []byte("HELLO-R-U-THERE"),
+		},
+	}
+	rb := make([]byte, 1500)
+
+next:
+	for i := 1; i <= 64; i++ { // up to 64 hops
+	repeat:
+		for j := 1; j <= 5; j++ {
+			wm.Body.(*icmp.Echo).Seq = i
+
+			wb, err := wm.Marshal(nil)
+			if err != nil {
+				return nil, err
+			}
+
+			err = p.SetTTL(i)
+			if err != nil {
+				return nil, err
+			}
+
+			_, err = p.WriteTo(wb, nil, &dst)
+			if err != nil {
+				return nil, err
+			}
+
+			err = p.SetReadDeadline(time.Now().Add(10 * time.Millisecond))
+			if err != nil {
+				return nil, err
+			}
+
+			// n, cm, peer, err := p.ReadFrom(rb)
+			// readping:
+			for {
+
+				n, _, peer, err := p.ReadFrom(rb)
+				if err != nil {
+					if err, ok := err.(net.Error); ok && err.Timeout() {
+						continue repeat
+					}
+					return nil, err
+				}
+
+				rm, err := icmp.ParseMessage(1, rb[:n])
+				if err != nil {
+					log.Fatal(err)
+				}
+
+				switch rm.Type {
+				case ipv4.ICMPTypeTimeExceeded:
+					ip := net.ParseIP(peer.String())
+					if ip == nil {
+						return nil, errors.New(fmt.Sprintf("failed to parse IP: %s", peer.String()))
+					}
+					if !netutils.IPIsLocal(ip) {
+						return ip, nil
+					}
+					continue next
+				case ipv4.ICMPTypeEchoReply:
+					continue next
+				default:
+					// log.Tracef("unknown ICMP message: %+v\n", rm)
+				}
+			}
+		}
+	}
+	return nil, nil
+}