tailscale/net/netutil/netutil_test.go
Anton Tolchanov 8cc5c51888 health: warn about reverse path filtering and exit nodes
When reverse path filtering is in strict mode on Linux, using an exit
node blocks all network connectivity. This change adds a warning about
this to `tailscale status` and the logs.

Example in `tailscale status`:

```
- not connected to home DERP region 22
- The following issues on your machine will likely make usage of exit nodes impossible: [interface "eth0" has strict reverse-path filtering enabled], please set rp_filter=2 instead of rp_filter=1; see https://github.com/tailscale/tailscale/issues/3310
```

Example in the logs:
```
2024/02/21 21:17:07 health("overall"): error: multiple errors:
	not in map poll
	The following issues on your machine will likely make usage of exit nodes impossible: [interface "eth0" has strict reverse-path filtering enabled], please set rp_filter=2 instead of rp_filter=1; see https://github.com/tailscale/tailscale/issues/3310
```

Updates #3310

Signed-off-by: Anton Tolchanov <anton@tailscale.com>
2024-02-27 00:43:01 +00:00

77 lines
1.4 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package netutil
import (
"io"
"net"
"runtime"
"testing"
)
type conn struct {
net.Conn
}
func TestOneConnListener(t *testing.T) {
c1 := new(conn)
a1 := dummyAddr("a1")
// Two Accepts
ln := NewOneConnListener(c1, a1)
if got := ln.Addr(); got != a1 {
t.Errorf("Addr = %#v; want %#v", got, a1)
}
c, err := ln.Accept()
if err != nil {
t.Fatal(err)
}
if c != c1 {
t.Fatalf("didn't get c1; got %p", c)
}
c, err = ln.Accept()
if err != io.EOF {
t.Errorf("got %v; want EOF", err)
}
if c != nil {
t.Errorf("unexpected non-nil Conn")
}
// Close before Accept
ln = NewOneConnListener(c1, a1)
ln.Close()
_, err = ln.Accept()
if err != io.EOF {
t.Fatalf("got %v; want EOF", err)
}
// Implicit addr
ln = NewOneConnListener(c1, nil)
if ln.Addr() == nil {
t.Errorf("nil Addr")
}
}
func TestIPForwardingEnabledLinux(t *testing.T) {
if runtime.GOOS != "linux" {
t.Skipf("skipping on %s", runtime.GOOS)
}
got, err := ipForwardingEnabledLinux(ipv4, "some-not-found-interface")
if err != nil {
t.Fatal(err)
}
if got {
t.Errorf("got true; want false")
}
}
func TestCheckReversePathFiltering(t *testing.T) {
if runtime.GOOS != "linux" {
t.Skipf("skipping on %s", runtime.GOOS)
}
warn, err := CheckReversePathFiltering(nil)
t.Logf("err: %v", err)
t.Logf("warnings: %v", warn)
}