[openwrt/openwrt] 6in4: Support fqdn as remote tunnel endpoint

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/6b5aea74293fe93e8abac411f9d974e8876e3252

commit 6b5aea74293fe93e8abac411f9d974e8876e3252
Author: Aleksandr V. Piskunov <aleksandr.v.piskunov at gmail.com>
AuthorDate: Tue Jul 16 16:44:35 2024 +0300

    6in4: Support fqdn as remote tunnel endpoint
    
    Same as fqdn support in GRE (commit a79f3d11b3) and IPIP (commit 311682905e)
    
    Signed-off-by: Aleksandr V. Piskunov <aleksandr.v.piskunov at gmail.com>
    Link: https://github.com/openwrt/openwrt/pull/15961
    Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 package/network/ipv6/6in4/Makefile      |  2 +-
 package/network/ipv6/6in4/files/6in4.sh | 15 ++++++++++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/package/network/ipv6/6in4/Makefile b/package/network/ipv6/6in4/Makefile
index edbb7d71a0..3c7dd4609b 100644
--- a/package/network/ipv6/6in4/Makefile
+++ b/package/network/ipv6/6in4/Makefile
@@ -16,7 +16,7 @@ include $(INCLUDE_DIR)/package.mk
 define Package/6in4
   SECTION:=net
   CATEGORY:=Network
-  DEPENDS:=@IPV6 +kmod-sit +uclient-fetch
+  DEPENDS:=@IPV6 +kmod-sit +uclient-fetch +resolveip
   TITLE:=IPv6-in-IPv4 configuration support
   MAINTAINER:=Jo-Philipp Wich <jo at mein.io>
   PKGARCH:=all
diff --git a/package/network/ipv6/6in4/files/6in4.sh b/package/network/ipv6/6in4/files/6in4.sh
index 99b2b76312..e500c6dec8 100755
--- a/package/network/ipv6/6in4/files/6in4.sh
+++ b/package/network/ipv6/6in4/files/6in4.sh
@@ -44,6 +44,7 @@ proto_6in4_setup() {
 	local cfg="$1"
 	local iface="$2"
 	local link="6in4-$cfg"
+	local remoteip
 
 	local mtu ttl tos ipaddr peeraddr ip6addr ip6prefix ip6prefixes tunlink tunnelid username password updatekey device
 	json_get_vars mtu ttl tos ipaddr peeraddr ip6addr tunlink tunnelid username password updatekey device
@@ -52,11 +53,23 @@ proto_6in4_setup() {
 	[ -n "$device" ] && link="$device"
 
 	[ -z "$peeraddr" ] && {
-		proto_notify_error "$cfg" "MISSING_ADDRESS"
+		proto_notify_error "$cfg" "MISSING_PEER_ADDRESS"
 		proto_block_restart "$cfg"
 		return
 	}
 
+	remoteip=$(resolveip -t 10 -4 "$peeraddr")
+
+	if [ -z "$remoteip" ]; then
+		proto_notify_error "$cfg" "PEER_RESOLVE_FAIL"
+		return
+	fi
+
+	for ip in $remoteip; do
+		peeraddr=$ip
+		break
+	done
+
 	( proto_add_host_dependency "$cfg" "$peeraddr" "$tunlink" )
 
 	[ -z "$ipaddr" ] && {