Release 2.6.1: resolve AWG endpoint hostnames to IP before connect.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/protocols/awg/conf_test.go

@@ -2,6 +2,7 @@ package awg
 
 import (
 	"encoding/base64"
+	"net"
 	"testing"
 )
 
@@ -139,6 +140,81 @@ func TestDecodeKeyURLSafe(t *testing.T) {
 	}
 }
 
+func TestResolveEndpointPrefersIPv4(t *testing.T) {
+	got, err := resolveEndpointWith("peer.example:41421", func(host string) ([]net.IP, error) {
+		if host != "peer.example" {
+			t.Fatalf("host %q", host)
+		}
+		return []net.IP{
+			net.ParseIP("2001:db8::1"),
+			net.ParseIP("203.0.113.44"),
+		}, nil
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "203.0.113.44:41421" {
+		t.Fatalf("got %q", got)
+	}
+}
+
+func TestResolveEndpointAlreadyIP(t *testing.T) {
+	got, err := resolveEndpointWith("203.0.113.10:51820", func(string) ([]net.IP, error) {
+		t.Fatal("lookup should not run for IP")
+		return nil, nil
+	})
+	if err != nil || got != "203.0.113.10:51820" {
+		t.Fatalf("%q %v", got, err)
+	}
+}
+
+func TestResolveEndpointDNSError(t *testing.T) {
+	_, err := resolveEndpointWith("missing.invalid:41421", func(string) ([]net.IP, error) {
+		return nil, &net.DNSError{Err: "no such host", Name: "missing.invalid", IsNotFound: true}
+	})
+	if err == nil || !stringsContains(err.Error(), "не удалось разрешить DNS") {
+		t.Fatalf("expected Russian DNS error, got %v", err)
+	}
+}
+
+func TestToIPCResolvesEndpoint(t *testing.T) {
+	old := lookupIP
+	lookupIP = func(host string) ([]net.IP, error) {
+		return []net.IP{net.ParseIP("198.51.100.9")}, nil
+	}
+	defer func() { lookupIP = old }()
+
+	c := Conf{
+		PrivateKey: "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=",
+		PublicKey:  "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEE=",
+		Address:    []string{"10.8.0.2/32"},
+		Endpoint:   "peer.example:41421",
+	}
+	ipc, err := c.ToIPC()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !stringsContains(ipc, "endpoint=198.51.100.9:41421") {
+		t.Fatalf("ipc missing resolved endpoint: %s", ipc)
+	}
+}
+
+func TestConfResolveEndpointMutates(t *testing.T) {
+	old := lookupIP
+	lookupIP = func(string) ([]net.IP, error) {
+		return []net.IP{net.ParseIP("198.51.100.1")}, nil
+	}
+	defer func() { lookupIP = old }()
+
+	c := Conf{Endpoint: "host.example:41421"}
+	if err := c.ResolveEndpoint(); err != nil {
+		t.Fatal(err)
+	}
+	if c.Endpoint != "198.51.100.1:41421" {
+		t.Fatalf("endpoint %q", c.Endpoint)
+	}
+}
+
 func containsAll(s string, parts ...string) bool {
 	for _, p := range parts {
 		if !stringsContains(s, p) {