From f1eb217ed282104ba7b6ee26f53fd0e019e7d1ae Mon Sep 17 00:00:00 2001
From: Olivier Poitrey <rs@nextdns.io>
Date: Sat, 7 Oct 2023 03:02:04 +0200
Subject: [PATCH] Add UDM content filtering feature detection

---
 install.sh            | 19 +++++++++++++++++++
 router/ubios/setup.go |  8 ++++++++
 2 files changed, 27 insertions(+)

diff --git a/install.sh b/install.sh
index fe108bda..45cf49cc 100755
--- a/install.sh
+++ b/install.sh
@@ -98,8 +98,23 @@ uninstall() {
     fi
 }
 
+precheck() {
+    if [ -e "/data/unifi" ] && [ -f "/run/dnsfilter/dnsfilter" ]; then
+        log_warn "UDM Content Filtering feature is enabled. Please disable it to use NextDNS."
+        log_warn ""
+        log_warn "  To disable it, go to Settings > Network"
+        log_warn "  For each network, set the Content Filtering feature to None."
+        log_warn ""
+        while [ -f "/run/dnsfilter/dnsfilter" ]; do
+            sleep 1
+        done
+        log_info "Content Filtering feature successfuly disabled."
+    fi
+}
+
 configure() {
     log_debug "Start configure"
+    precheck
     args=""
     add_arg() {
         for value in $2; do
@@ -666,6 +681,10 @@ log_info() {
     printf "INFO: %s\n" "$*" >&2
 }
 
+log_warn() {
+    printf "\033[33mWARN: %s\033[0m\n" "$*" >&2
+}
+
 log_error() {
     printf "\033[31mERROR: %s\033[0m\n" "$*" >&2
 }
diff --git a/router/ubios/setup.go b/router/ubios/setup.go
index 93942ae9..99cae7d0 100644
--- a/router/ubios/setup.go
+++ b/router/ubios/setup.go
@@ -28,6 +28,9 @@ func New() (*Router, bool) {
 }
 
 func (r *Router) Configure(c *config.Config) error {
+	if dnsFilterEnabled() {
+		return fmt.Errorf(`UDM "Content Filtering" feature is enabled. Please disable it to use NextDNS.`)
+	}
 	c.Listens = []string{net.JoinHostPort("localhost", r.ListenPort)}
 	r.ClientReporting = c.ReportClientInfo
 	if c.CacheSize == "0" || c.CacheSize == "" {
@@ -55,6 +58,11 @@ func (r *Router) setupDNSMasq() error {
 	return killDNSMasq()
 }
 
+func dnsFilterEnabled() bool {
+	_, err := os.Stat("/run/dnsfilter/dnsfilter")
+	return err == nil
+}
+
 func killDNSMasq() error {
 	b, err := os.ReadFile("/run/dnsmasq.pid")
 	if err != nil {