feat(netdetect): detect WAN interface, gateways and addresses

2026-10-15 14:29:19 +03:30
parent 150a78bdde
commit 83871815c2
2 changed files with 314 additions and 0 deletions
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: MIT
+
+package netdetect
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"prx/internal/execx"
+)
+
+func fake(handler func(name string, args []string) (string, error)) *execx.Fake {
+	return &execx.Fake{Handler: func(name string, args []string, _ []byte) (execx.Result, error) {
+		out, err := handler(name, args)
+		if err != nil {
+			return execx.Result{}, err
+		}
+		return execx.Result{Stdout: []byte(out)}, nil
+	}}
+}
+
+func TestDetect(t *testing.T) {
+	r := fake(func(name string, args []string) (string, error) {
+		joined := strings.Join(args, " ")
+		switch {
+		case joined == "-j route show default":
+			return `[{"dst":"default","gateway":"192.168.1.1","dev":"wlan0","metric":600}]`, nil
+		case joined == "-6 -j route show default":
+			return `[]`, nil
+		case joined == "-j addr show dev wlan0":
+			return `[{"ifname":"wlan0","addr_info":[
+				{"family":"inet","local":"192.168.1.100","prefixlen":24,"scope":"global"},
+				{"family":"inet6","local":"fe80::abcd","prefixlen":64,"scope":"link"}]}]`, nil
+		}
+		return "", nil
+	})
+
+	wan, err := Detect(context.Background(), r, "", "", "")
+	if err != nil {
+		t.Fatalf("Detect: %v", err)
+	}
+	if wan.Interface != "wlan0" {
+		t.Errorf("interface = %q", wan.Interface)
+	}
+	if wan.Gateway4 != "192.168.1.1" {
+		t.Errorf("gateway4 = %q", wan.Gateway4)
+	}
+	if wan.Gateway6 != "" {
+		t.Errorf("gateway6 = %q, want empty", wan.Gateway6)
+	}
+	if len(wan.Local4) != 1 || wan.Local4[0] != "192.168.1.100" {
+		t.Errorf("local4 = %v", wan.Local4)
+	}
+	if len(wan.Local6) != 0 {
+		t.Errorf("local6 = %v, want none (link-local excluded)", wan.Local6)
+	}
+}
+
+func TestDetectPrefersLowestMetric(t *testing.T) {
+	r := fake(func(_ string, args []string) (string, error) {
+		joined := strings.Join(args, " ")
+		if joined == "-j route show default" {
+			return `[{"dst":"default","gateway":"10.0.0.1","dev":"eth9","metric":900},
+			         {"dst":"default","gateway":"192.168.1.1","dev":"wlan0","metric":100}]`, nil
+		}
+		if strings.Contains(joined, "addr show dev wlan0") {
+			return `[{"ifname":"wlan0","addr_info":[{"family":"inet","local":"192.168.1.100","prefixlen":24,"scope":"global"}]}]`, nil
+		}
+		return `[]`, nil
+	})
+	wan, err := Detect(context.Background(), r, "", "", "")
+	if err != nil {
+		t.Fatalf("Detect: %v", err)
+	}
+	if wan.Interface != "wlan0" || wan.Gateway4 != "192.168.1.1" {
+		t.Fatalf("picked %s/%s, want wlan0/192.168.1.1", wan.Interface, wan.Gateway4)
+	}
+}
+
+func TestDetectOverride(t *testing.T) {
+	r := fake(func(_ string, args []string) (string, error) {
+		if strings.Join(args, " ") == "-j route show default" {
+			return `[{"dst":"default","gateway":"192.168.1.1","dev":"wlan0","metric":100}]`, nil
+		}
+		if strings.Contains(strings.Join(args, " "), "addr show dev wlan0") {
+			return `[{"ifname":"wlan0","addr_info":[{"family":"inet","local":"192.168.1.100","prefixlen":24,"scope":"global"}]}]`, nil
+		}
+		return `[]`, nil
+	})
+	wan, err := Detect(context.Background(), r, "wlan0", "10.9.9.9", "")
+	if err != nil {
+		t.Fatalf("Detect: %v", err)
+	}
+	if wan.Gateway4 != "10.9.9.9" {
+		t.Fatalf("gateway override not applied: %q", wan.Gateway4)
+	}
+}
+
+func TestDetectNoDefaultRoute(t *testing.T) {
+	r := fake(func(_ string, _ []string) (string, error) { return `[]`, nil })
+	if _, err := Detect(context.Background(), r, "", "", ""); err == nil {
+		t.Fatal("expected error when no default route exists")
+	}
+}
+
+func TestDetectIPv6OnlyUplink(t *testing.T) {
+	r := fake(func(_ string, args []string) (string, error) {
+		joined := strings.Join(args, " ")
+		switch {
+		case joined == "-j route show default":
+			return `[]`, nil
+		case joined == "-6 -j route show default":
+			return `[{"dst":"default","gateway":"2001:db8::1","dev":"eth0","metric":100}]`, nil
+		case joined == "-j addr show dev eth0":
+			return `[{"ifname":"eth0","addr_info":[{"family":"inet6","local":"2001:db8::5","prefixlen":64,"scope":"global"}]}]`, nil
+		}
+		return `[]`, nil
+	})
+	wan, err := Detect(context.Background(), r, "", "", "")
+	if err != nil {
+		t.Fatalf("Detect: %v", err)
+	}
+	if wan.Interface != "eth0" || wan.Gateway4 != "" || wan.Gateway6 != "2001:db8::1" {
+		t.Fatalf("ipv6-only detection = %+v", wan)
+	}
+}