feat: Enhance resolveDefault to handle Stage 2 failures and fallback to Stage 3 A queries

README.md

@@ -1,4 +1,4 @@
-# ekekDNSHelper
+# ekDNSHelper
 
 A cross-platform CLI tool that resolves hostnames against DNS servers and writes the resulting IP-to-hostname mappings into the local hosts file. It manages a clearly delimited block within the hosts file so it can cleanly add and remove only its own entries.
 
@@ -6,7 +6,7 @@ By default, ekdns performs **smart resolution**: it discovers the authoritative
 
 Built as a single static binary with no runtime dependencies.
 
-**Copyright (c) 2024 Emberkom LLC**
+**Copyright (c) 2026 Emberkom LLC**
 
 ## Features
 

build.ps1

@@ -78,12 +78,14 @@ if (-not (Test-Path $OutputDir)) {
     Write-Host "Created output directory: $OutputDir" -ForegroundColor Green
 }
 
-# Build flags
-$ldflags = ""
+# Build flags — always inject version and copyright year; release builds also strip debug symbols.
+$buildYear = (Get-Date).Year
+$injectedFlags = "-X main.version=$gitTag -X main.copyrightYear=$buildYear"
 if ($Release) {
-    $ldflags = "-s -w"
+    $ldflags = "-s -w $injectedFlags"
     Write-Host "Building RELEASE version (optimized, no debug symbols)..." -ForegroundColor Green
 } else {
+    $ldflags = $injectedFlags
     Write-Host "Building DEBUG version (with debug symbols)..." -ForegroundColor Yellow
 }
 

hostfile/hostfile.go

@@ -11,6 +11,13 @@ import (
 const (
 	StartMarker = "# ekDNSHelper <<-> START CONFIG"
 	EndMarker   = "# ekDNSHelper <->> END CONFIG"
+
+	// Legacy markers from the pre-rename "DNSHelper" era.
+	// ParseManagedBlock recognises these so that hosts files written by
+	// the old binary are detected, parsed, and silently upgraded to the
+	// current markers on the next write.
+	LegacyStartMarker = "# DNSHelper <<-> START CONFIG"
+	LegacyEndMarker   = "# DNSHelper <->> END CONFIG"
 )
 
 // DNSEntry represents a single IP-to-hostname mapping.

hostfile/managed.go

@@ -17,13 +17,17 @@ func ParseManagedBlock(lines []string) (prefix, managed, postfix []string, hasMa
 	endCount := 0
 
 	for i, line := range lines {
-		if strings.Contains(line, "ekDNSHelper <<-> START CONFIG") {
+		// Recognise both current and legacy markers so that hosts files
+		// written by the old "DNSHelper" binary are parsed correctly.
+		if strings.Contains(line, "ekDNSHelper <<-> START CONFIG") ||
+			strings.Contains(line, "DNSHelper <<-> START CONFIG") {
 			startCount++
 			if startIdx == -1 {
 				startIdx = i
 			}
 		}
-		if strings.Contains(line, "ekDNSHelper <->> END CONFIG") {
+		if strings.Contains(line, "ekDNSHelper <->> END CONFIG") ||
+			strings.Contains(line, "DNSHelper <->> END CONFIG") {
 			endCount++
 			if endIdx == -1 {
 				endIdx = i
@@ -57,6 +61,19 @@ func ParseManagedBlock(lines []string) (prefix, managed, postfix []string, hasMa
 	return prefix, managed, postfix, true, nil
 }
 
+// lineMatchesHostname parses a hosts-file line ("IP<whitespace>hostname [aliases...]")
+// and returns true if any hostname field (including aliases) matches,
+// using case-insensitive comparison per RFC 4343.
+func lineMatchesHostname(line, hostname string) bool {
+	fields := strings.Fields(line)
+	for _, f := range fields[1:] {
+		if strings.EqualFold(f, hostname) {
+			return true
+		}
+	}
+	return false
+}
+
 // AddEntries removes existing entries for the same hostnames as the new entries,
 // then appends the new entries. Returns deduplicated managed content lines.
 func AddEntries(existing []string, entries []DNSEntry) []string {
@@ -71,7 +88,7 @@ func AddEntries(existing []string, entries []DNSEntry) []string {
 	for _, line := range existing {
 		keep := true
 		for h := range hostnames {
-			if strings.Contains(line, h) {
+			if lineMatchesHostname(line, h) {
 				keep = false
 				break
 			}
@@ -101,7 +118,7 @@ func RemoveByHostname(existing []string, hostnames []string) []string {
 	for _, line := range existing {
 		shouldRemove := false
 		for _, host := range hostnames {
-			if strings.Contains(line, host) {
+			if lineMatchesHostname(line, host) {
 				shouldRemove = true
 				break
 			}

hostfile/managed_test.go

@@ -159,6 +159,134 @@ func TestParseManagedBlock_CorruptDuplicateMarkers(t *testing.T) {
 	}
 }
 
+// ---------------------------------------------------------------------------
+// ParseManagedBlock — legacy marker tests
+// ---------------------------------------------------------------------------
+
+func TestParseManagedBlock_LegacyMarkers(t *testing.T) {
+	lines := []string{
+		"127.0.0.1 localhost",
+		hostfile.LegacyStartMarker,
+		"1.1.1.1\thost1",
+		"2.2.2.2\thost2",
+		hostfile.LegacyEndMarker,
+		"# trailing comment",
+	}
+	prefix, managed, postfix, has, err := hostfile.ParseManagedBlock(lines)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !has {
+		t.Fatal("expected HasManagedBlock=true for legacy markers")
+	}
+	if len(prefix) != 1 || prefix[0] != "127.0.0.1 localhost" {
+		t.Errorf("unexpected prefix: %v", prefix)
+	}
+	if len(managed) != 2 {
+		t.Errorf("expected 2 managed lines, got %v", managed)
+	}
+	if len(postfix) != 1 || postfix[0] != "# trailing comment" {
+		t.Errorf("unexpected postfix: %v", postfix)
+	}
+}
+
+func TestParseManagedBlock_LegacyStartMarkerAtLine0(t *testing.T) {
+	lines := []string{
+		hostfile.LegacyStartMarker,
+		"1.1.1.1\thost1",
+		hostfile.LegacyEndMarker,
+	}
+	prefix, managed, postfix, has, err := hostfile.ParseManagedBlock(lines)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !has {
+		t.Fatal("expected HasManagedBlock=true")
+	}
+	if len(prefix) != 0 {
+		t.Errorf("expected empty prefix, got %v", prefix)
+	}
+	if len(managed) != 1 || managed[0] != "1.1.1.1\thost1" {
+		t.Errorf("unexpected managed: %v", managed)
+	}
+	if len(postfix) != 0 {
+		t.Errorf("expected empty postfix, got %v", postfix)
+	}
+}
+
+func TestParseManagedBlock_LegacyCorruptStartWithoutEnd(t *testing.T) {
+	lines := []string{
+		"127.0.0.1 localhost",
+		hostfile.LegacyStartMarker,
+		"1.1.1.1\thost1",
+	}
+	_, _, _, _, err := hostfile.ParseManagedBlock(lines)
+	if err == nil {
+		t.Fatal("expected error for legacy start marker without end marker")
+	}
+}
+
+func TestParseManagedBlock_LegacyCorruptEndWithoutStart(t *testing.T) {
+	lines := []string{
+		"127.0.0.1 localhost",
+		"1.1.1.1\thost1",
+		hostfile.LegacyEndMarker,
+	}
+	_, _, _, _, err := hostfile.ParseManagedBlock(lines)
+	if err == nil {
+		t.Fatal("expected error for legacy end marker without start marker")
+	}
+}
+
+func TestParseManagedBlock_MixedOldStartNewEnd(t *testing.T) {
+	// Legacy start with current end — still a valid block (both substrings match).
+	lines := []string{
+		"127.0.0.1 localhost",
+		hostfile.LegacyStartMarker,
+		"1.1.1.1\thost1",
+		hostfile.EndMarker,
+	}
+	_, managed, _, has, err := hostfile.ParseManagedBlock(lines)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !has {
+		t.Fatal("expected HasManagedBlock=true for mixed markers")
+	}
+	if len(managed) != 1 {
+		t.Errorf("expected 1 managed line, got %v", managed)
+	}
+}
+
+func TestParseManagedBlock_LegacyUpgradedOnWrite(t *testing.T) {
+	// Verify that a legacy block is parsed and then reassembled with current markers.
+	lines := []string{
+		"127.0.0.1 localhost",
+		hostfile.LegacyStartMarker,
+		"1.1.1.1\thost1",
+		hostfile.LegacyEndMarker,
+		"# trailing",
+	}
+	prefix, managed, postfix, _, err := hostfile.ParseManagedBlock(lines)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	result := hostfile.AssembleContent(prefix, managed, postfix)
+	// The reassembled output should use the current markers, not legacy.
+	found := false
+	for _, l := range result {
+		if l == hostfile.StartMarker {
+			found = true
+		}
+		if l == hostfile.LegacyStartMarker {
+			t.Fatal("reassembled content should not contain legacy start marker")
+		}
+	}
+	if !found {
+		t.Fatal("reassembled content should contain current start marker")
+	}
+}
+
 // ---------------------------------------------------------------------------
 // AddEntries tests
 // ---------------------------------------------------------------------------
@@ -201,6 +329,52 @@ func TestAddEntries_ReplacesExistingHostname(t *testing.T) {
 	}
 }
 
+func TestAddEntries_DoesNotClobberSubdomains(t *testing.T) {
+	// Regression: substring matching would cause adding "example.com" to
+	// incorrectly remove "sub.example.com" entries.
+	existing := []string{
+		"1.1.1.1\tsub.example.com",
+		"2.2.2.2\tother.example.com",
+	}
+	entries := []hostfile.DNSEntry{{IP: "9.9.9.9", Hostname: "example.com"}}
+	result := hostfile.AddEntries(existing, entries)
+	if len(result) != 3 {
+		t.Fatalf("expected 3 entries (2 existing + 1 new), got %d: %v", len(result), result)
+	}
+	for _, line := range result {
+		if line == "1.1.1.1\tsub.example.com" || line == "2.2.2.2\tother.example.com" || line == "9.9.9.9\texample.com" {
+			continue
+		}
+		t.Errorf("unexpected line: %q", line)
+	}
+}
+
+func TestAddEntries_MatchesAliasColumn(t *testing.T) {
+	// A hosts-file line can have aliases: "IP primary alias1 alias2"
+	// Replacing "alias1" should remove the entire line.
+	existing := []string{"1.1.1.1\tprimary\talias1"}
+	entries := []hostfile.DNSEntry{{IP: "9.9.9.9", Hostname: "alias1"}}
+	result := hostfile.AddEntries(existing, entries)
+	for _, line := range result {
+		if strings.Contains(line, "primary") {
+			t.Errorf("line with alias1 should have been removed, but found: %q", line)
+		}
+	}
+}
+
+func TestAddEntries_CaseInsensitive(t *testing.T) {
+	// RFC 4343: hostnames are case-insensitive.
+	existing := []string{"1.1.1.1\tHost1.Example.COM"}
+	entries := []hostfile.DNSEntry{{IP: "9.9.9.9", Hostname: "host1.example.com"}}
+	result := hostfile.AddEntries(existing, entries)
+	if len(result) != 1 {
+		t.Fatalf("expected 1 entry (old replaced), got %d: %v", len(result), result)
+	}
+	if result[0] != "9.9.9.9\thost1.example.com" {
+		t.Errorf("expected new entry, got %q", result[0])
+	}
+}
+
 func TestAddEntries_Deduplicates(t *testing.T) {
 	existing := []string{"1.1.1.1\thost1"}
 	entries := []hostfile.DNSEntry{
@@ -332,6 +506,54 @@ func TestRemoveByHostname_RegressionNoDuplicates(t *testing.T) {
 	}
 }
 
+func TestRemoveByHostname_DoesNotClobberSubdomains(t *testing.T) {
+	// Regression: substring matching would remove "sub.example.com" when
+	// only "example.com" was requested for removal.
+	existing := []string{
+		"1.1.1.1\texample.com",
+		"2.2.2.2\tsub.example.com",
+		"3.3.3.3\tmy-example.com",
+	}
+	result := hostfile.RemoveByHostname(existing, []string{"example.com"})
+	if len(result) != 2 {
+		t.Fatalf("expected 2 remaining entries, got %d: %v", len(result), result)
+	}
+	if result[0] != "2.2.2.2\tsub.example.com" {
+		t.Errorf("expected sub.example.com to remain, got %q", result[0])
+	}
+	if result[1] != "3.3.3.3\tmy-example.com" {
+		t.Errorf("expected my-example.com to remain, got %q", result[1])
+	}
+}
+
+func TestRemoveByHostname_MatchesAliasColumn(t *testing.T) {
+	existing := []string{
+		"1.1.1.1\tprimary\talias1",
+		"2.2.2.2\thost2",
+	}
+	result := hostfile.RemoveByHostname(existing, []string{"alias1"})
+	if len(result) != 1 {
+		t.Fatalf("expected 1 remaining entry, got %d: %v", len(result), result)
+	}
+	if result[0] != "2.2.2.2\thost2" {
+		t.Errorf("expected host2 to remain, got %q", result[0])
+	}
+}
+
+func TestRemoveByHostname_CaseInsensitive(t *testing.T) {
+	existing := []string{
+		"1.1.1.1\tHost1.Example.COM",
+		"2.2.2.2\thost2",
+	}
+	result := hostfile.RemoveByHostname(existing, []string{"host1.example.com"})
+	if len(result) != 1 {
+		t.Fatalf("expected 1 remaining entry, got %d: %v", len(result), result)
+	}
+	if result[0] != "2.2.2.2\thost2" {
+		t.Errorf("expected host2 to remain, got %q", result[0])
+	}
+}
+
 // ---------------------------------------------------------------------------
 // RemoveAll tests (T018)
 // ---------------------------------------------------------------------------

main.go

@@ -14,10 +14,14 @@ import (
 	"ekdns/resolver"
 )
 
+// version and copyrightYear are set at build time via -ldflags.
+var version = "dev"
+var copyrightYear = "2024"
+
 func main() {
 	// Banner (always printed to stdout).
-	fmt.Println("ekDNSHelper v1.0")
-	fmt.Println("Copyright (c) 2024 Emberkom LLC")
+	fmt.Printf("ekDNSHelper %s\n", version)
+	fmt.Printf("Copyright (c) %s Emberkom LLC\n", copyrightYear)
 	fmt.Println("")
 
 	if len(os.Args) < 2 {

resolver/modes.go

@@ -85,11 +85,19 @@ func resolveDefault(hostname string, pool []string, localResolvers []string, con
 	if authority != nil {
 		fmt.Fprintf(w, "[dns] Selected authority: %s → %s\n",
 			authority.Zone, strings.Join(authority.Nameservers, ", "))
-		return resolveAuthoritative(ctx, authority, hostname, pool, localResolvers, config, depth, w)
+		ips, err := resolveAuthoritative(ctx, authority, hostname, pool, localResolvers, config, depth, w)
+		if err == nil {
+			return ips, nil
+		}
+		// Stage 2 failed (e.g. sub-zone delegation referral not followed) —
+		// fall through to Stage 3 parallel A fallback.
+		fmt.Fprintf(w, "[dns] Stage 2 failed: %v\n", err)
+		fmt.Fprintf(w, "[dns] Falling back to Stage 3 parallel A queries\n")
+	} else {
+		fmt.Fprintf(w, "[dns] Stage 1: No NS records found at any level\n")
 	}
 
-	// Stage 3: No NS records found — fall back to parallel A queries.
-	fmt.Fprintf(w, "[dns] Stage 1: No NS records found at any level\n")
+	// Stage 3: Fall back to parallel recursive A queries.
 	ips, err := ParallelAFallback(ctx, w, pool, hostname, timeout)
 	if err != nil {
 		return nil, addPrivateTLDHint(hostname, err)