From: Dan Fuhry <dan@fuhry.com>
Date: Thu, 12 Sep 2024 04:46:25 +0000 (-0400)
Subject: dns: exclude 169.254.0.0/16 from lookup results, too
X-Git-Url: https://go.fuhry.dev/?a=commitdiff_plain;h=7a15acd6330dd94c441b1f7c9028fd82c39d459b;p=runtime.git

dns: exclude 169.254.0.0/16 from lookup results, too
---

diff --git a/net/dns/dns_cache.go b/net/dns/dns_cache.go
index 0270b0d..4700e5b 100644
--- a/net/dns/dns_cache.go
+++ b/net/dns/dns_cache.go
@@ -23,6 +23,11 @@ var loopbackIPv4 = net.IPNet{
 	Mask: net.IPMask{255, 0, 0, 0},
 }
 
+var autoPrivateIPv4 = net.IPNet{
+	IP:   net.IP{169, 254, 0, 0},
+	Mask: net.IPMask{255, 255, 0, 0},
+}
+
 var localIPv6 = net.IPNet{
 	IP: net.IP{
 		0xfe, 0x80, 0x00, 0x00,
@@ -69,7 +74,7 @@ func ResolveDualStack(hostname string) (string, string, error) {
 	for _, rr := range msg.Answer {
 		switch a := rr.(type) {
 		case *dns.A:
-			if !loopbackIPv4.Contains(a.A) {
+			if !loopbackIPv4.Contains(a.A) && !autoPrivateIPv4.Contains(a.A) {
 				ip4 = a.A.String()
 			}
 		case *dns.AAAA: