feat(init.d/podkop): add secure DNS probe domain configuration

podkop/files/etc/init.d/podkop

@@ -149,6 +149,7 @@ main() {
     sing_box_dns
     sing_box_dns_rule_fakeip
     sing_box_rule_dns
+    sing_box_add_secure_dns_probe_domain
     sing_box_cache_file
     process_socks5
 
@@ -727,6 +728,37 @@ sing_box_rule_dns() {
     }' $SING_BOX_CONFIG >/tmp/sing-box-config-tmp.json && mv /tmp/sing-box-config-tmp.json $SING_BOX_CONFIG
 }
 
+sing_box_add_secure_dns_probe_domain() {
+    local domain="example.com"
+    local override_address="neverssl.com"
+
+    log "Configure DNS probe domain ${domain}"
+
+    jq \
+    --arg domain "$domain" \
+    --arg override "$override_address" \
+    '.dns.rules |= map(
+        if .server == "fakeip-server" then
+            {
+                "server": .server,
+                "domain": $domain,
+                "rule_set": .rule_set
+            }
+        else
+            .
+        end
+    ) |
+    .route.rules |= . + [
+        {
+            "domain": $domain,
+            "action": "route-options",
+            "override_address": $override
+        }
+    ]' "$SING_BOX_CONFIG" >/tmp/sing-box-config-tmp.json && mv /tmp/sing-box-config-tmp.json "$SING_BOX_CONFIG"
+
+    log "DNS probe domain ${domain} configured with override to ${override_address}"
+}
+
 sing_box_config_check() {
     if ! sing-box -c $SING_BOX_CONFIG check >/dev/null 2>&1; then
         log "Sing-box configuration is invalid"