add scripts

customize.sh

@@ -0,0 +1,6 @@
+#!/system/bin/sh
+
+# prepare data directory
+. $MODPATH/utils.sh
+
+set_perm $MODPATH/system/bin/mydns 0 0 777

default.conf

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+# upstream servers (may be specified several times)
+upstream_server=8.8.8.8
+upstream_server=8.8.4.4
+# args directly passed to dnsmasq executable
+dnsmasq_args=--domain-needed --bogus-priv --cache-size=1000
+# port of the local server
+server_port=5353
+# port for outgoing connections made by server
+output_port=5354

post-fs-data.sh

@@ -0,0 +1,11 @@
+#!/system/bin/sh
+MODDIR=${0%/*}
+. $MODDIR/utils.sh
+
+# point the script back to module directory
+# (in case mount point gets changed)
+sed -i "s|=.*MODDIR_PLACEHOLDER|=$MODDIR # MODDIR_PLACEHOLDER|" "$MODDIR/system/bin/mydns"
+
+# generate resolv.conf
+upstream_servers=$(load_cfg_val upstream_server)
+write_resolv_conf

service.sh

@@ -0,0 +1,41 @@
+#!/system/bin/sh
+# Do NOT assume where your module will be located.
+# ALWAYS use $MODDIR if you need to know where this script
+# and module is placed.
+# This will make sure your module will still work
+# if Magisk change its mount point in the future
+MODDIR=${0%/*}
+. $MODDIR/utils.sh
+
+# This script will be executed in late_start service mode
+
+add_iptables_redirect() {
+  local protocol=$1
+  local address=$2
+  local dest_port=$3
+  local src_port=$4
+
+  local command="iptables -A OUTPUT -w -t nat -p $protocol --dport 53 -j DNAT --to-destination $address:$dest_port"
+  if [ "$src_port" != "" ]; then
+    command="$command --sport $src_port --destination $address"
+  fi
+  eval "$command"
+  echo "$command" | sed "s/-A/-D/" >> "$RESTORE_IPTABLES"
+}
+
+# clear restore file
+echo -n > "$RESTORE_IPTABLES"
+
+load_config
+
+# only output_port will be able to communicate with outer world
+for server in $upstream_servers; do
+  add_iptables_redirect tcp $server 53 $output_port
+  add_iptables_redirect udp $server 53 $output_port
+done
+
+# redirect all outgoing connections to local server
+add_iptables_redirect tcp 127.0.0.1 $server_port
+add_iptables_redirect udp 127.0.0.1 $server_port
+
+run_dnsmasq

system/bin/mydns

@@ -0,0 +1,86 @@
+#!/system/bin/sh
+
+if [ "$ASH_STANDALONE" = "" ]; then
+  ASH_STANDALONE=1 /data/adb/magisk/busybox ash "$0" "$1"
+  exit
+fi
+
+MODDIR=MODDIR_PLACEHOLDER
+. $MODDIR/utils.sh
+
+start() {
+  sh $MODDIR/service.sh </dev/null &>/dev/null &
+}
+
+stop() {
+  sh $RESTORE_IPTABLES
+  kill $(cat $PIDFILE)
+  rm -f $PIDFILE
+}
+
+check_running() {
+  if [ -f $PIDFILE ]; then
+    return 0
+  else
+    return 1
+  fi
+}
+
+case "$1" in
+  "start")
+    if check_running; then
+      echo "The service is already running."
+    else
+      start
+    fi
+    ;;
+  "stop")
+    if check_running; then
+      stop
+    else
+      echo "The service is not running."
+    fi
+    ;;
+  "restart")
+    if check_running; then
+      stop && start
+    else
+      echo "The service is not running."
+    fi
+    ;;
+  "config")
+    if [ "$EDITOR" = "" ]; then
+      EDITOR=nano
+    fi
+    temp_dir=$(mktemp -d)
+    temp_conf="$temp_dir/$(basename $CONFIG)"
+    cp $CONFIG "$temp_conf"
+    if [ "$(command -v "$EDITOR")" = "" ]; then
+      echo "Editor '$EDITOR' not found."
+      echo "Point to your text editor via EDITOR variable."
+    else
+      "$EDITOR" "$temp_conf"
+      load_config "$temp_conf"
+      if check_config; then
+        cp "$temp_conf" $CONFIG
+        write_resolv_conf
+        echo "Config was updated."
+      else
+        echo "Config was not updated."
+      fi
+    fi
+    rm -r "$temp_dir"
+    ;;
+  *)
+    echo -n "Status: "
+    if check_running; then
+      echo "running"
+      echo "Resources consumed:"
+      top -b -n 2 -d 0.2 | grep -E "^ *$(cat $PIDFILE) " | tail -1 \
+        | awk '{"nproc" | getline n; print "CPU " $8 * n "%\nRAM " $6 "%"}'
+    else
+      echo "stopped"
+    fi
+    echo "Available commands: start, restart, stop, config"
+    ;;
+esac

uninstall.sh

@@ -0,0 +1,6 @@
+#!/system/bin/sh
+MODDIR=${0%/*}
+
+. "$MODDIR/utils.sh"
+
+rm -fr "$DATADIR"

utils.sh

@@ -0,0 +1,88 @@
+if [ "$MODPATH" != "" ]; then
+  MODDIR=$MODPATH
+elif [ "$MODDIR" = "" ]; then
+  MODDIR=${0%/*}
+fi
+DATADIR=/data/mydns
+CONFIG=$DATADIR/mydns.conf
+PIDFILE=$DATADIR/dnsmasq.pid
+RESTORE_IPTABLES=$DATADIR/restore_iptables
+
+mkdir -p $DATADIR
+if [ ! -f $CONFIG ]; then
+  cp $MODDIR/default.conf $CONFIG
+fi
+
+if [ "$(command -v ui_print)" = "" ]; then
+  alias ui_print=echo
+fi
+
+DNSMASQ=$DATADIR/dnsmasq
+if [ ! -x $DNSMASQ ]; then
+  cp /data/data/com.termux/files/usr/bin/dnsmasq $DATADIR
+  if [ $? != 0 ]; then
+    ui_print "WARNING: dnsmasq not found in Termux."
+    ui_print "WARNING: Standard dnsmasq may cause abnormal CPU usage."
+    ui_print "WARNING: Install dnsmasq in Termux and reflash the module."
+    DNSMASQ=dnsmasq
+  fi
+fi
+
+load_cfg_val() {
+  if [ "$2" != "" ]; then
+    local file="$2"
+  else
+    local file="$CONFIG"
+  fi
+  sed -n "s|^$1=||p" "$file"
+}
+
+load_config() {
+  server_port=$(load_cfg_val server_port "$1")
+  output_port=$(load_cfg_val output_port "$1")
+  upstream_servers=$(load_cfg_val upstream_server "$1")
+  dnsmasq_args=$(load_cfg_val dnsmasq_args "$1")
+}
+
+check_config() {
+  local has_servers=0
+  local server
+  for server in $upstream_servers; do
+    has_servers=1
+    if ! echo ".$server" | grep -Eq '^(\.[0-9]{1,3}){4}$'; then
+      echo "'$server' doesn't look like a valid IP address."
+      return 1
+    fi
+  done
+  if [ $has_servers = 0 ]; then
+    echo "No upstream servers specified."
+    return 1
+  fi
+  local port
+  for port in "$server_port" "$output_port"; do
+    if ! echo "$port" | grep -Eq '^[0-9]+$'; then
+      echo "'$port' doesn't look like a valid port."
+      return 1
+    fi
+  done
+  if [ "$server_port" = "$output_port" ]; then
+    echo "server_port and output_port cannot be the same."
+    return 1
+  fi
+  if ! run_dnsmasq --test; then
+    return 1
+  fi
+  return 0
+}
+
+write_resolv_conf() {
+  echo -n > "$MODDIR/system/etc/resolv.conf"
+  local server
+  for server in $upstream_servers; do
+    echo "nameserver $server" >> "$MODDIR/system/etc/resolv.conf"
+  done
+}
+
+run_dnsmasq() {
+  $DNSMASQ --pid-file=$PIDFILE --port $server_port -Q $output_port $dnsmasq_args $1
+}