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// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
package netmon
import (
"io"
"net/netip"
"os/exec"
"testing"
"go4.org/mem"
"tailscale.com/util/lineiter"
"tailscale.com/version"
)
func TestLikelyHomeRouterIPSyscallExec(t *testing.T) {
syscallIP, _, syscallOK := likelyHomeRouterIPBSDFetchRIB()
netstatIP, netstatIf, netstatOK := likelyHomeRouterIPDarwinExec()
if syscallOK != netstatOK || syscallIP != netstatIP {
t.Errorf("syscall() = %v, %v, netstat = %v, %v",
syscallIP, syscallOK,
netstatIP, netstatOK,
)
}
if !syscallOK {
return
}
def, err := defaultRoute()
if err != nil {
t.Errorf("defaultRoute() error: %v", err)
}
if def.InterfaceName != netstatIf {
t.Errorf("syscall default route interface %s differs from netstat %s", def.InterfaceName, netstatIf)
}
}
/*
Parse out 10.0.0.1 and en0 from:
$ netstat -r -n -f inet
Routing tables
Internet:
Destination Gateway Flags Netif Expire
default 10.0.0.1 UGSc en0
default link#14 UCSI utun2
10/16 link#4 UCS en0 !
10.0.0.1/32 link#4 UCS en0 !
...
*/
func likelyHomeRouterIPDarwinExec() (ret netip.Addr, netif string, ok bool) {
if version.IsMobile() {
// Don't try to do subprocesses on iOS. Ends up with log spam like:
// kernel: "Sandbox: IPNExtension(86580) deny(1) process-fork"
// This is why we have likelyHomeRouterIPDarwinSyscall.
return ret, "", false
}
cmd := exec.Command("/usr/sbin/netstat", "-r", "-n", "-f", "inet")
stdout, err := cmd.StdoutPipe()
if err != nil {
return
}
if err := cmd.Start(); err != nil {
return
}
defer cmd.Wait()
defer io.Copy(io.Discard, stdout) // clear the pipe to prevent hangs
var f []mem.RO
for lr := range lineiter.Reader(stdout) {
lineb, err := lr.Value()
if err != nil {
break
}
line := mem.B(lineb)
if !mem.Contains(line, mem.S("default")) {
continue
}
f = mem.AppendFields(f[:0], line)
if len(f) < 4 || !f[0].EqualString("default") {
continue
}
ipm, flagsm, netifm := f[1], f[2], f[3]
if !mem.Contains(flagsm, mem.S("G")) {
continue
}
if mem.Contains(flagsm, mem.S("I")) {
continue
}
ip, err := netip.ParseAddr(string(mem.Append(nil, ipm)))
if err == nil && ip.IsPrivate() {
ret = ip
netif = netifm.StringCopy()
// We've found what we're looking for.
break
}
}
return ret, netif, ret.IsValid()
}
func TestFetchRoutingTable(t *testing.T) {
// Issue 1345: this used to be flaky on darwin.
for range 20 {
_, err := fetchRoutingTable()
if err != nil {
t.Fatal(err)
}
}
}
func TestUpdateLastKnownDefaultRouteInterface(t *testing.T) {
// Pick some interface on the machine
interfaces, err := netInterfaces()
if err != nil || len(interfaces) == 0 {
t.Fatalf("netInterfaces() error: %v", err)
}
// Set it as our last known default route interface
ifName := interfaces[0].Name
UpdateLastKnownDefaultRouteInterface(ifName)
// And make sure we can get it back
route, err := OSDefaultRoute()
if err != nil {
t.Fatalf("OSDefaultRoute() error: %v", err)
}
want, got := ifName, route.InterfaceName
if want != got {
t.Errorf("OSDefaultRoute() = %q, want %q", got, want)
}
}
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