[openwrt/openwrt] dnsmasq: include IPv6 local nameserver entry

[LEDE Commits]

dedeckeh pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/d7db32440fd5d5eee015896ec19e583513bb9bae

commit d7db32440fd5d5eee015896ec19e583513bb9bae
Author: Joel Johnson <mrjoel at lixil.net>
AuthorDate: Fri Aug 21 08:32:00 2020 -0600

    dnsmasq: include IPv6 local nameserver entry
    
    For IPv6 native connections when using IPv6 DNS lookups, there is no
    valid default resolver if ignoring WAN DHCP provided nameservers.
    
    This uses a runtime check to determine if IPv6 is supported on the host.
    
    Signed-off-by: Joel Johnson <mrjoel at lixil.net>
---
 package/network/services/dnsmasq/files/dnsmasq.init | 1 +
 1 file changed, 1 insertion(+)

diff --git a/package/network/services/dnsmasq/files/dnsmasq.init b/package/network/services/dnsmasq/files/dnsmasq.init
index 0fa3074f92..7ecc542b44 100644
--- a/package/network/services/dnsmasq/files/dnsmasq.init
+++ b/package/network/services/dnsmasq/files/dnsmasq.init
@@ -1066,6 +1066,7 @@ dnsmasq_start()
 			echo "search $DOMAIN" >> /tmp/resolv.conf
 		}
 		DNS_SERVERS="$DNS_SERVERS 127.0.0.1"
+		[ -e /proc/sys/net/ipv6 ] && DNS_SERVERS="$DNS_SERVERS ::1"
 		for DNS_SERVER in $DNS_SERVERS ; do
 			echo "nameserver $DNS_SERVER" >> /tmp/resolv.conf
 		done