code.dwrz.net

commit 60e4d329c8deae3336cd72bc6b02027be8dbb4c0
parent 067012781ca8481713ae66ac1fcf29e56d7d5016
Author: dwrz <dwrz@dwrz.net>
Date:   Fri, 14 Oct 2022 00:33:20 +0000

Add digip pkg

Diffstat:
A
pkg/digip/digip.go
 | 
85
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
pkg/digip/digip_test.go
 | 
54
++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 139 insertions(+), 0 deletions(-)
diff --git a/pkg/digip/digip.go b/pkg/digip/digip.go
@@ -0,0 +1,85 @@
+package digip
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"os/exec"
+	"strings"
+)
+
+type Version string
+
+const (
+	V4 = "-4"
+	V6 = "-6"
+)
+
+type Record string
+
+const (
+	A    = "A"
+	AAAA = "AAAA"
+)
+
+// dig -4 TXT +short o-o.myaddr.l.google.com @ns1.google.com
+// dig -6 TXT +short o-o.myaddr.l.google.com @ns1.google.com
+func Google(ctx context.Context, v Version) (net.IP, error) {
+	cmd := exec.CommandContext(
+		ctx,
+		"dig",
+		"TXT",
+		"+short",
+		string(v),
+		"o-o.myaddr.l.google.com",
+		"@ns1.google.com",
+	)
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		return nil, fmt.Errorf("dig failed: %v", err)
+	}
+	if string(output) == "" {
+		return nil, fmt.Errorf("dig failed: no output")
+	}
+	if len(output) < 2 {
+		return nil, fmt.Errorf(
+			"dig failed: unexpected output: %s", string(output),
+		)
+	}
+
+	// Google returns the IP with quotes.
+	// We need to trim the quotes.
+	trimmed := strings.TrimSpace(string(output))
+	ip := net.ParseIP(trimmed[1 : len(trimmed)-1])
+
+	return ip, nil
+}
+
+// dig A +short myip.opendns.com @resolver1.opendns.com
+// dig AAAA +short myip.opendns.com @resolver1.opendns.com
+func OpenDNS(ctx context.Context, r Record) (net.IP, error) {
+	cmd := exec.CommandContext(
+		ctx,
+		"dig",
+		"+short",
+		string(r),
+		"myip.opendns.com",
+		"@resolver1.opendns.com",
+	)
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		return nil, fmt.Errorf("dig failed: %v", err)
+	}
+	if string(output) == "" {
+		return nil, fmt.Errorf("dig failed: no output")
+	}
+	if len(output) < 2 {
+		return nil, fmt.Errorf(
+			"dig failed: unexpected output: %s", string(output),
+		)
+	}
+
+	ip := net.ParseIP(strings.TrimSpace(string(output)))
+
+	return ip, nil
+}
diff --git a/pkg/digip/digip_test.go b/pkg/digip/digip_test.go
@@ -0,0 +1,54 @@
+package digip
+
+import (
+	"context"
+	"testing"
+)
+
+func TestGoogleV4(t *testing.T) {
+	ctx := context.Background()
+
+	ip, err := Google(ctx, V4)
+	if err != nil {
+		t.Errorf("google v4 failed: %v", err)
+		return
+	}
+
+	t.Logf("got ip: %s", ip)
+}
+
+func TestGoogleV6(t *testing.T) {
+	ctx := context.Background()
+
+	ip, err := Google(ctx, V6)
+	if err != nil {
+		t.Errorf("google v6 failed: %v", err)
+		return
+	}
+
+	t.Logf("got ip: %s", ip)
+}
+
+func TestOpenDNSV4(t *testing.T) {
+	ctx := context.Background()
+
+	ip, err := OpenDNS(ctx, A)
+	if err != nil {
+		t.Errorf("opendns A failed: %v", err)
+		return
+	}
+
+	t.Logf("got ip: %s", ip)
+}
+
+func TestOpenDNSV6(t *testing.T) {
+	ctx := context.Background()
+
+	ip, err := OpenDNS(ctx, AAAA)
+	if err != nil {
+		t.Errorf("opendns AAAA failed: %v", err)
+		return
+	}
+
+	t.Logf("got ip: %s", ip)
+}