[openwrt/openwrt] dnsmasq: prevent upstream resolution of addresses

[LEDE Commits]

robimarko pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/38753dea6405fcc3b92994b0926d3bfd4760345f

commit 38753dea6405fcc3b92994b0926d3bfd4760345f
Author: Marko Zajc <marko at zajc.tel>
AuthorDate: Sat Apr 26 14:21:10 2025 +0200

    dnsmasq: prevent upstream resolution of addresses
    
    `list address` entries in /etc/config/dhcp are sometimes (I'm not sure
    about the exact conditions) passed to upstream resolver, bypassing local
    resolution. Adding them (minus the IP) to --local prevents this. In the
    configuration, this means that
    
        # /etc/config/dhcp
        list address '/hello.com/world.com/1.2.3.4'
        list address '/foo.com/bar.com/4.3.2.1'
    
    which previously translated into
    
        # /var/etc/dnsmasq.conf.*
        address=/hello.com/world.com/1.2.3.4
        address=/foo.com/bar.com/4.3.2.1
    
    now becomes
    
        # /var/etc/dnsmasq.conf.*
        address=/hello.com/world.com/1.2.3.4
        local=/hello.com/world.com/
        address=/foo.com/bar.com/4.3.2.1
        local=/foo.com/bar.com/
    
    This behaviour is controlled by the `address_as_local` boolean option, which
    defaults to false (old behaviour). openwrt/luci#7957 adds support for this flag
    to LuCI.
    
    A workaround for a small list of domains is to add them to `option local`,
    but this is very tedious to do for every `list address` entry and dnsmasq
    limits this option to 1024 characters.
    
    Signed-off-by: Marko Zajc <marko at zajc.tel>
    Link: https://github.com/openwrt/openwrt/pull/18610
    Signed-off-by: Robert Marko <robimarko at gmail.com>
---
 package/network/services/dnsmasq/files/dnsmasq.init | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/package/network/services/dnsmasq/files/dnsmasq.init b/package/network/services/dnsmasq/files/dnsmasq.init
index a0a644fcbd..61dc396707 100755
--- a/package/network/services/dnsmasq/files/dnsmasq.init
+++ b/package/network/services/dnsmasq/files/dnsmasq.init
@@ -170,7 +170,9 @@ append_rev_server() {
 }
 
 append_address() {
+	local address_as_local="$2"
 	xappend "--address=$1"
+	[ $address_as_local -gt 0 ] && xappend "--local=${1%/*}/"
 }
 
 append_connmark_allowlist() {
@@ -1036,7 +1038,10 @@ dnsmasq_start()
 	config_list_foreach "$cfg" "listen_address" append_listenaddress
 	config_list_foreach "$cfg" "server" append_server
 	config_list_foreach "$cfg" "rev_server" append_rev_server
-	config_list_foreach "$cfg" "address" append_address
+
+	local address_as_local
+	config_get address_as_local "$cfg" address_as_local 0
+	config_list_foreach "$cfg" "address" append_address "$address_as_local"
 
 	local connmark_allowlist_enable
 	config_get connmark_allowlist_enable "$cfg" connmark_allowlist_enable 0