From 449d27b00ea822dabe6be42a7ee72cabebee3001 Mon Sep 17 00:00:00 2001
From: Steven Kreitzer <skre@skre.me>
Date: Wed, 11 Dec 2024 10:05:49 -0600
Subject: [PATCH] fix: allow ipv4-mapped ipv6 addresses

Signed-off-by: Steven Kreitzer <skre@skre.me>
---
 source/source.go      | 21 +++++----------------
 source/source_test.go |  1 +
 2 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/source/source.go b/source/source.go
index 132f40dcd9..012cf82739 100644
--- a/source/source.go
+++ b/source/source.go
@@ -21,7 +21,7 @@ import (
 	"context"
 	"fmt"
 	"math"
-	"net"
+	"net/netip"
 	"reflect"
 	"strconv"
 	"strings"
@@ -255,11 +255,12 @@ func getTargetsFromTargetAnnotation(annotations map[string]string) endpoint.Targ
 }
 
 // suitableType returns the DNS resource record type suitable for the target.
-// In this case type A for IPs and type CNAME for everything else.
+// In this case type A/AAAA for IPs and type CNAME for everything else.
 func suitableType(target string) string {
-	if net.ParseIP(target) != nil && net.ParseIP(target).To4() != nil {
+	netIP, err := netip.ParseAddr(target)
+	if err == nil && netIP.Is4() {
 		return endpoint.RecordTypeA
-	} else if net.ParseIP(target) != nil && net.ParseIP(target).To16() != nil {
+	} else if err == nil && netIP.Is6() {
 		return endpoint.RecordTypeAAAA
 	}
 	return endpoint.RecordTypeCNAME
@@ -276,14 +277,8 @@ func endpointsForHostname(hostname string, targets endpoint.Targets, ttl endpoin
 	for _, t := range targets {
 		switch suitableType(t) {
 		case endpoint.RecordTypeA:
-			if isIPv6String(t) {
-				continue
-			}
 			aTargets = append(aTargets, t)
 		case endpoint.RecordTypeAAAA:
-			if !isIPv6String(t) {
-				continue
-			}
 			aaaaTargets = append(aaaaTargets, t)
 		default:
 			cnameTargets = append(cnameTargets, t)
@@ -387,9 +382,3 @@ func waitForDynamicCacheSync(ctx context.Context, factory dynamicInformerFactory
 	}
 	return nil
 }
-
-// isIPv6String returns if ip is IPv6.
-func isIPv6String(ip string) bool {
-	netIP := net.ParseIP(ip)
-	return netIP != nil && netIP.To4() == nil
-}
diff --git a/source/source_test.go b/source/source_test.go
index 417a3c14e5..17a3c4a7fb 100644
--- a/source/source_test.go
+++ b/source/source_test.go
@@ -85,6 +85,7 @@ func TestSuitableType(t *testing.T) {
 	}{
 		{"8.8.8.8", "", "A"},
 		{"2001:db8::1", "", "AAAA"},
+		{"::ffff:c0a8:101", "", "AAAA"},
 		{"foo.example.org", "", "CNAME"},
 		{"bar.eu-central-1.elb.amazonaws.com", "", "CNAME"},
 	} {