don't reset interface

README.md

@@ -6,7 +6,6 @@ It wraps `iptables`, `dnsmasq` etc. stuff. Use in one command, restore in one co
 
 [Linux-Router News & Developer Notes 📰](https://github.com/garywill/linux-router/issues/28) | [More tools and projects 🛠️](https://garywill.github.io) | [🍻 Buy me a coffee ❤️](https://github.com/garywill/receiving/blob/master/receiving_methods.md)
 
-
 ## Features
 
 Basic features:
@@ -62,31 +61,6 @@ Internet----(eth0/wlan0)-Linux-(eth1)------Another PC
 Internet----(eth0/wlan0)-Linux-(virtual interface)-----VM/container
 ```
 
-## Install
-
-1-file-script. Release on [Linux-router repo on Github](https://github.com/garywill/linux-router). Just download and run the bash script (meet the dependencies). In this case use without installation.
-
-> I'm currently not packaging for any distro. If you do, open a PR and add the link (can be with a version badge) to list here
-
-| Linux distro |                                                                                                            |
-| ------------ | ---------------------------------------------------------------------------------------------------------- |
-| Any          | download [1-file-script](https://raw.githubusercontent.com/garywill/linux-router/master/lnxrouter) and run without installation |
-
-### Dependencies
-
-- bash
-- procps or procps-ng
-- iproute2
-- dnsmasq
-- iptables (or nftables with `iptables-nft` translation linked)
-- WiFi hotspot dependencies
-  - hostapd
-  - iw
-  - iwconfig (you only need this if 'iw' can not recognize your adapter)
-  - haveged (optional)
-
-
-
 ## Usage
 
 ### Provide Internet to an interface
@@ -118,13 +92,13 @@ sudo lnxrouter -i eth1 -o isp5  --no-dns  --dhcp-dns 1.1.1.1  -6 --dhcp-dns6 [26
 > In this case of usage, it's recommended to:
 > 
 > 1. Stop serving local DNS
-> 2. Tell clients which DNS to use ISP5's DNS. (Or, a safe public DNS, like above example)
+> 2. Tell clients which DNS to use (ISP5's DNS. Or, a safe public DNS, like above example)
 
 > Also, read *Notice 1*
 
 </details>
 
-### Create LAN without providing Internet
+### LAN without Internet
 
 <details>
 
@@ -164,7 +138,7 @@ sudo lnxrouter -i lxcbr5
 
 ### Transparent proxy
 
-All clients' Internet traffic go through, for example, Tor (notice this example is NOT an anonymity use)
+All clients' Internet traffic go through, for example, Tor
 
 <details>
 
@@ -181,10 +155,6 @@ TransPort [fd00:5:6:7::1]:9040
 DNSPort [fd00:5:6:7::1]:9053
 ```
 
-> **Warn**: Tor's anonymity relies on a purpose-made browser. Using Tor like this (sharing Tor's network to LAN clients) will NOT ensure anonymity.
-> 
-> Although we use Tor as example here, Linux-router does NOT ensure nor is NOT aiming at anonymity.
-
 </details>
 
 ### Clients-in-sandbox network
@@ -203,7 +173,7 @@ sudo lnxrouter -i eth1 \
 
 </details>
 
-> Linux-router comes with no warranty. Use on your own risk
+> This script comes with no warrenty. Use on your own risk
 
 ### Use as transparent proxy for LXD
 
@@ -347,28 +317,26 @@ Options:
     -d                      DNS server will take into account /etc/hosts
     -e <hosts_file>         DNS server will take into account additional 
                             hosts file
-    --dns-nocache           DNS server no cache
 
     --mac <MAC>             Set MAC address
     --random-mac            Use random MAC address
 
     --tp <port>             Transparent proxy,
-                            redirect non-LAN TCP and UDP(not tested) traffic to
+                            redirect non-LAN TCP and UDP traffic to port.
-                            port. (usually used with '--dns')
+                            (usually used with '--dns')
 
   WiFi hotspot options:
     --ap <wifi interface> <SSID>
                             Create WiFi access point
     -p, --password <password>   
                             WiFi password
-    --qr                    Show WiFi QR code in terminal (need qrencode)
+    --qr                    Show WiFi QR code in terminal
 
     --hidden                Hide access point (not broadcast SSID)
     --no-virt               Do not create virtual interface
                             Using this you can't use same wlan interface
                             for both Internet and AP
-    --virt-name <name>      Set name of virtual interface
+    -c <channel>            Channel number (default: 1)
-    -c <channel>            Specify channel (default: use current, or 1 / 36)
     --country <code>        Set two-letter country code for regularity
                             (example: US)
     --freq-band <GHz>       Set frequency band: 2.4 or 5 (default: 2.4)
@@ -382,28 +350,13 @@ Options:
                             (defaults to /etc/hostapd/hostapd.accept)
     --hostapd-debug <level> 1 or 2. Passes -d or -dd to hostapd
     --isolate-clients       Disable wifi communication between clients
+
+    --ieee80211n            Enable IEEE 802.11n (HT)
+    --ieee80211ac           Enable IEEE 802.11ac (VHT)
+    --ht_capab <HT>         HT capabilities (default: [HT40+])
+    --vht_capab <VHT>       VHT capabilities
+
     --no-haveged            Do not run haveged automatically when needed
-    --hs20                  Enable Hotspot 2.0
-
-    WiFi 4 (802.11n) configs:
-    --wifi4                 Enable IEEE 802.11n (HT)
-    --req-ht                Require station HT (High Throughput) mode
-    --ht-capab <HT caps>    HT capabilities (default: [HT40+])
-
-    WiFi 5 (802.11ac) configs:
-    --wifi5                 Enable IEEE 802.11ac (VHT)
-    --req-vht               Require station VHT (Very High Thoughtput) mode
-    --vht-capab <VHT caps>  VHT capabilities
-    
-    --vht-ch-width <index>  Index of VHT channel width:
-                                0 for 20MHz or 40MHz (default)
-                                1 for 80MHz
-                                2 for 160MHz
-                                3 for 80+80MHz (Non-contigous 160MHz)    
-    --vht-seg0-ch <channel> Channel index of VHT center frequency for primary 
-                            segment. Use with '--vht-ch-width'
-    --vht-seg1-ch <channel> Channel index of VHT center frequency for secondary
-                            (second 80MHz) segment. Use with '--vht-ch-width 3'
 
   Instance managing:
     --daemon                Run in background
@@ -415,7 +368,15 @@ Options:
     --stop <id>             Stop a running instance
         For <id> you can use PID or subnet interface name.
         You can get them with '--list-running'
+```
 
+</details>
+
+## Notice
+
+<details>
+
+```
     Notice 1:   This script assume your host's default policy won't forward
                 packets, so the script won't explictly ban forwarding in any
                 mode. In some unexpected case (eg. mistaken configurations) may
@@ -436,35 +397,19 @@ On exit of a linux-router instance, script **will do cleanup**, i.e. undo most c
 5. The wifi device which is used to create hotspot is `rfkill unblock`ed
 6. WiFi country code, if user assigns
 
-## Meet contributor(s) and become one of them
+## Dependencies
 
-Visit [**my homepage** 🏡](https://garywill.github.io) to see **more tools and projects** 🛠️.
+- bash
-
+- procps or procps-ng
-> [❤️ Buy me a coffee](https://github.com/garywill/receiving/blob/master/receiving_methods.md) , this project took me lots of time! ([❤️ 扫码领红包并打赏一个!](https://github.com/garywill/receiving/blob/master/receiving_methods.md))
+- iproute2
-> 
+- dnsmasq
-> 🥂 ( ^\_^) o自自o (^_^ ) 🍻
+- iptables (or nftables with `iptables-nft` translation linked)
-
+- WiFi hotspot dependencies
-🤝 Bisides, thank [create_ap](https://github.com/oblique/create_ap) by [oblique](https://github.com/oblique). This script was forked from create\_ap. Now they are quite different. (See `history` branch for how I modified create_ap). 🤝 Also thank those who contributed to that project.
+  - hostapd
-
+  - iw
-👨‍💻 You can be contributor, too! 
+  - iwconfig (you only need this if 'iw' can not recognize your adapter)
-
+  - haveged (optional)
-- 🍃 There're some TO-DOs listed, in both [readme TODO](#todo) and [in the code file](https://github.com/garywill/linux-router/search?q=TODO&type=code)
+  - qrencode (optional)
-- 🍃 Also some [unfulfilled enhancements in the Issues](https://github.com/garywill/linux-router/issues?q=is%3Aissue+is%3Aopen+label%3Aenhancement)
-- 🙋‍♂️ Contributions are not limited to coding. There're [some posts and questions](https://github.com/garywill/linux-router/issues) that need more people to answer
-
-## Notice
-
-<details>
-
-```
-    Notice 1:   This script assume your host's default policy won't forward
-                packets, so the script won't explictly ban forwarding in any
-                mode. In some unexpected case (eg. mistaken configurations) may
-                cause unwanted packets leakage between 2 networks, which you
-                should be aware of if you want isolated network
-```
-
-</details>
 
 ## TODO
 
@@ -536,4 +481,14 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 </details>
 
+## Meet developer(s) and become one of them
 
+Visit [**my homepage** 🏡](https://garywill.github.io) to see **more tools and projects** 🛠️.
+
+> [❤️ Buy me a coffee](https://github.com/garywill/receiving/blob/master/receiving_methods.md) , this project took me lots of time! ([❤️ 扫码领红包并打赏一个!](https://github.com/garywill/receiving/blob/master/receiving_methods.md))
+> 
+> 🥂 ( ^\_^) o自自o (^_^ ) 🍻
+
+🤝 Bisides, thank [create_ap](https://github.com/oblique/create_ap) by [oblique](https://github.com/oblique). This script was forked from create\_ap. Now they are quite different. (See `history` branch for how I modified create_ap). 🤝 Also thank those who contributed to that project.
+
+👨‍💻 You can be contributor, too! 🍃 There're some TO-DOs listed, at both [above](#todo) and [in the code file](https://github.com/garywill/linux-router/search?q=TODO&type=code). 🍃 Also some [unfulfilled enhancements in the Issues](https://github.com/garywill/linux-router/issues?q=is%3Aissue+is%3Aopen+label%3Aenhancement). Your name can be here!

lnxrouter

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-VERSION=0.7.1b
+VERSION=0.6.6
 PROGNAME="$(basename $0)"
 
 export LC_ALL=C
@@ -67,28 +67,26 @@ Options:
     -d                      DNS server will take into account /etc/hosts
     -e <hosts_file>         DNS server will take into account additional 
                             hosts file
-    --dns-nocache           DNS server no cache
     
     --mac <MAC>             Set MAC address
     --random-mac            Use random MAC address
  
     --tp <port>             Transparent proxy,
-                            redirect non-LAN TCP and UDP(not tested) traffic to
+                            redirect non-LAN TCP and UDP traffic to port.
-                            port. (usually used with '--dns')
+                            (usually used with '--dns')
     
   WiFi hotspot options:
     --ap <wifi interface> <SSID>
                             Create WiFi access point
     -p, --password <password>   
                             WiFi password
-    --qr                    Show WiFi QR code in terminal (need qrencode)
+    --qr                    Show WiFi QR code in terminal
     
     --hidden                Hide access point (not broadcast SSID)
     --no-virt               Do not create virtual interface
                             Using this you can't use same wlan interface
                             for both Internet and AP
-    --virt-name <name>      Set name of virtual interface
+    -c <channel>            Channel number (default: 1)
-    -c <channel>            Specify channel (default: use current, or 1 / 36)
     --country <code>        Set two-letter country code for regularity
                             (example: US)
     --freq-band <GHz>       Set frequency band: 2.4 or 5 (default: 2.4)
@@ -102,28 +100,13 @@ Options:
                             (defaults to /etc/hostapd/hostapd.accept)
     --hostapd-debug <level> 1 or 2. Passes -d or -dd to hostapd
     --isolate-clients       Disable wifi communication between clients
+    
+    --ieee80211n            Enable IEEE 802.11n (HT)
+    --ieee80211ac           Enable IEEE 802.11ac (VHT)
+    --ht_capab <HT>         HT capabilities (default: [HT40+])
+    --vht_capab <VHT>       VHT capabilities
+    
     --no-haveged            Do not run haveged automatically when needed
-    --hs20                  Enable Hotspot 2.0
-
-    WiFi 4 (802.11n) configs:
-    --wifi4                 Enable IEEE 802.11n (HT)
-    --req-ht                Require station HT (High Throughput) mode
-    --ht-capab <HT caps>    HT capabilities (default: [HT40+])
-
-    WiFi 5 (802.11ac) configs:
-    --wifi5                 Enable IEEE 802.11ac (VHT)
-    --req-vht               Require station VHT (Very High Thoughtput) mode
-    --vht-capab <VHT caps>  VHT capabilities
-    
-    --vht-ch-width <index>  Index of VHT channel width:
-                                0 for 20MHz or 40MHz (default)
-                                1 for 80MHz
-                                2 for 160MHz
-                                3 for 80+80MHz (Non-contigous 160MHz)    
-    --vht-seg0-ch <channel> Channel index of VHT center frequency for primary 
-                            segment. Use with '--vht-ch-width'
-    --vht-seg1-ch <channel> Channel index of VHT center frequency for secondary
-                            (second 80MHz) segment. Use with '--vht-ch-width 3'
 
   Instance managing:
     --daemon                Run in background
@@ -173,7 +156,6 @@ define_global_variables(){
     SHOW_DNS_QUERY=0  # log dns
     ETC_HOSTS=0
     ADDN_HOSTS=
-    DNS_NOCACHE=
     CONN_IFACE=    # which interface user choose to use to create network
     INTERNET_IFACE= # which interface to get Internet from
     THISHOSTNAME=   # this host's name the DNS tells clients 
@@ -194,19 +176,13 @@ define_global_variables(){
     HIDDEN=0 # hidden wifi hotspot
     WIFI_IFACE=
     CHANNEL=default 
-    HOTSPOT20=0 # For enabling Hotspot 2.0
     WPA_VERSION=2
     MAC_FILTER=0
     MAC_FILTER_ACCEPT=/etc/hostapd/hostapd.accept
     IEEE80211N=0
-    REQUIREHT=0
     IEEE80211AC=0
-    REQUIREVHT=0
     HT_CAPAB='[HT40+]'
     VHT_CAPAB=
-    VHTCHANNELWIDTH=0
-    VHTSEG0CHINDEX=0
-    VHTSEG1CHINDEX=0
     DRIVER=nl80211
     NO_VIRT=0 # not use virtual interface
     COUNTRY=
@@ -219,7 +195,6 @@ define_global_variables(){
     
     # script variables
     VWIFI_IFACE=  # virtual wifi interface name, if created
-    VIRT_NAME= # name to use for virtual interface if --virt-name is used
     AP_IFACE=     # can be VWIFI_IFACE or WIFI_IFACE
     USE_IWCONFIG=0  # some device can't use iw
     
@@ -347,10 +322,6 @@ parse_user_options(){
                 ADDN_HOSTS="$1"
                 shift
                 ;;
-            --dns-nocache)
-                shift
-                DNS_NOCACHE=1
-                ;;
             
             --isolate-clients)
                 shift
@@ -394,10 +365,6 @@ parse_user_options(){
                 CHANNEL="$1"
                 shift
                 ;;
-            --hs20)
-                shift
-                HOTSPOT20=1
-                ;;
             -w)
                 shift
                 WPA_VERSION="$1"
@@ -405,47 +372,24 @@ parse_user_options(){
                 shift
                 ;;
 
-            --wifi4|--ieee80211n)
+            --ieee80211n)
                 shift
                 IEEE80211N=1
                 ;;
-            --req-ht|--require-ht)
+            --ieee80211ac)
-                shift
-                REQUIREHT=1
-                ;;
-            --wifi5|--ieee80211ac)
                 shift
                 IEEE80211AC=1
                 ;;
-            --req-vht|--require-vht)
+            --ht_capab)
-                shift
-                REQUIREVHT=1
-                ;;
-            --ht-capab)
                 shift
                 HT_CAPAB="$1"
                 shift
                 ;;
-            --vht-capab)
+            --vht_capab)
                 shift
                 VHT_CAPAB="$1"
                 shift
                 ;;
-            --vht-ch-width|--vht-channel-width)
-                shift
-                VHTCHANNELWIDTH="$1"
-                shift
-                ;;
-            --vht-seg0-ch|--vht-seg0-channel)
-                shift
-                VHTSEG0CHINDEX="$1"
-                shift
-                ;;
-            --vht-seg1-ch|--vht-seg1-channel)
-                shift
-                VHTSEG1CHINDEX="$1"
-                shift
-                ;;
             --driver)
                 shift
                 DRIVER="$1"
@@ -455,11 +399,6 @@ parse_user_options(){
                 shift
                 NO_VIRT=1
                 ;;
-            --virt-name)
-                shift
-                VIRT_NAME="$1"
-                shift
-                ;;
 
             --country)
                 shift
@@ -566,10 +505,6 @@ is_interface() {
     [[ -d "/sys/class/net/${1}" ]]
 }
 
-is_vface_name_allocated(){
-    is_interface "$1" || [[ -f "$COMMON_CONFDIR/vfaces/${1}" ]]
-}
-
 get_interface_phy_device() { # only for wifi interface
     local x
     for x in /sys/class/ieee80211/*; do
@@ -716,19 +651,20 @@ get_interface_pci_info() {  # pci id / model / virtual
     # TODO current driver
 }
 
+
 alloc_new_vface_name() { # only for wifi
     local i=0
-    local v_iface_name="$VIRT_NAME"
+    local v_iface_name=
-    if [[ -z $VIRT_NAME ]]; then
     while :; do
         v_iface_name="x$i${WIFI_IFACE}"
-            i=$((i + 1))
+        if ! is_interface ${v_iface_name} && [[ ! -f $COMMON_CONFDIR/vfaces/${v_iface_name} ]]; then
-            is_vface_name_allocated ${v_iface_name} || break
-        done
-    fi
             mkdir -p $COMMON_CONFDIR/vfaces
             touch $COMMON_CONFDIR/vfaces/${v_iface_name}
             echo "${v_iface_name}"
+            return
+        fi
+        i=$((i + 1))
+    done
 }
 
 dealloc_vface_name() {
@@ -1085,7 +1021,7 @@ allow_dhcp() {
 # TODO: use 'DNAT' instead of '--to-ports' to support other IP
 start_redsocks() {
     echo
-    echo "iptables: transparent proxy non-LAN TCP and UDP(not tested) traffic to port ${TP_PORT}"
+    echo "iptables: transparent proxy non-LAN TCP/UDP traffic to port ${TP_PORT}"
     if [[ $NO4 -eq 0 ]]; then
         iptb 4 n nat N lrt${$}${SUBNET_IFACE}-TP || die
         iptb 4 n nat A lrt${$}${SUBNET_IFACE}-TP -d 0.0.0.0/8 -j RETURN || die
@@ -1183,10 +1119,6 @@ backup_interface_status() {
     # nm managing status is saved when nm_set_unmanaged()
 }
 restore_interface_status() {
-    # virtual wifi interface will be destroyed, so no need to restore status
-    # don't use [[ $VWIFI_IFACE ]] to judge, if creating virtual wifi failed, VWIFI_IFACE is empty
-    [[ "$WIFI_IFACE" && "$NO_VIRT" -eq 0 ]] && return
-    
     restore_ipv6_bits
 
     if [[ -n "$OLD_MACADDR" && "$(get_interface_mac $SUBNET_IFACE)" != "$OLD_MACADDR" ]] ; then
@@ -1196,7 +1128,6 @@ restore_interface_status() {
     
     nm_restore_manage
     
-    [[ $SUBNET_IFACE_ORIGINAL_UP_STATUS -eq 1 ]] && ip link set up dev ${SUBNET_IFACE} && echo "Restore ${SUBNET_IFACE} to link up"
 }
 #---------------------------------------
 
@@ -1219,12 +1150,7 @@ kill_processes() { # for this instance
 _cleanup() {
     local x
 
-    ip addr flush ${SUBNET_IFACE}
-    
     rm -rf $CONFDIR
-    
-    ip link set down dev ${SUBNET_IFACE}
-    
     if [[ $VWIFI_IFACE ]]; then # the subnet interface (virtual wifi interface) will be removed
         iw dev ${VWIFI_IFACE} del
         dealloc_vface_name $VWIFI_IFACE
@@ -1271,7 +1197,7 @@ cleanup() {
     #kill -9 -$pgid
 }
 
-# NOTE function die() is designed NOT to be used before init_trap() executed
+# NOTE function die() is designed not to be used before init_trap() executed
 die() { # SIGUSR2
     echo "Error occured"
     [[ -n "$1" ]] && echo -e "\nERROR: $1\n" >&2
@@ -1554,7 +1480,7 @@ daemonizing_check(){
 check_wifi_settings() {
 
     if ! ( which iw > /dev/null 2>&1 && iw dev $WIFI_IFACE info > /dev/null 2>&1 ); then
-        echo "WARN: Can't use 'iw' to operate interfce '$WIFI_IFACE', trying 'iwconfig' (not as good as 'iw') ... (Did you spell the interface name right?)" >&2
+        echo "WARN: Can't use 'iw' to operate interfce '$WIFI_IFACE', trying 'iwconfig' (not as good as 'iw') ..." >&2
         USE_IWCONFIG=1
     fi
     
@@ -1570,6 +1496,14 @@ check_wifi_settings() {
         exit 1
     fi
 
+    if [[ $CHANNEL == default ]]; then
+        if [[ $FREQ_BAND == 2.4 ]]; then
+            CHANNEL=1
+        else
+            CHANNEL=36
+        fi
+    fi
+
     if [[ $FREQ_BAND != 5 && $CHANNEL -gt 14 ]]; then
         echo "Channel number is greater than 14, assuming 5GHz frequency band"
         FREQ_BAND=5
@@ -1625,18 +1559,6 @@ check_wifi_settings() {
         fi
         echo "WARN: If AP doesn't work, read https://github.com/oblique/create_ap/blob/master/howto/realtek.md" >&2
     fi
-
-    if [[ -z $VIRT_NAME ]]; then
-        if [[ ${#WIFI_IFACE} -gt 13 ]]; then
-            echo "WARN: $WIFI_IFACE has ${#WIFI_IFACE} characters which might be too long. If AP doesn't work, see --virt-name and https://github.com/garywill/linux-router/issues/44" >&2
-        fi
-    elif [[ ${#VIRT_NAME} -gt 15 ]]; then
-        echo "WARN: option --virt-name $VIRT_NAME has ${#VIRT_NAME} characters which might be too long, consider making it shorter in case of errors" >&2
-    fi
-
-    if [[ ! -z $VIRT_NAME ]] && is_vface_name_allocated $VIRT_NAME; then
-      echo "WARN: interface $VIRT_NAME aleady exists, this will cause an error"
-    fi
 }
 
 check_if_new_mac_valid() {
@@ -1664,15 +1586,13 @@ decide_target_interface() {
 
 decide_ip_addresses() {
     if [[ ! -n $GATEWAY ]]; then
-        GATEWAY="$(generate_random_ip4)"
+        echo
-        echo "Use random LAN IPv4 address $GATEWAY"
     elif [[ ! "$GATEWAY" =~ "." ]]; then
         GATEWAY="192.168.${GATEWAY}.1"
     fi
 
     if [[ $IPV6 -eq 1 && ! -n $PREFIX6 ]]; then
-        PREFIX6="$(generate_random_lan_ip6_prefix)"
+        echo
-        echo "Use random LAN IPv6 address ${PREFIX6}${IID6}"
     elif [[ ! "$PREFIX6" =~ ":" ]]; then
         PREFIX6="fd00:0:0:${PREFIX6}::"
     fi
@@ -1688,21 +1608,20 @@ prepare_wifi_interface() {
     
     if [[ $NO_VIRT -eq 0 ]]; then
     ## Will generate virtual wifi interface
-    
-        # TODO move this to check_wifi_settings() ?
         if is_interface_wifi_connected ${WIFI_IFACE}; then
             WIFI_IFACE_FREQ=$(iw dev ${WIFI_IFACE} link | grep -i freq | awk '{print $2}')
             WIFI_IFACE_CHANNEL=$(ieee80211_frequency_to_channel ${WIFI_IFACE_FREQ})
-            
+            echo "${WIFI_IFACE} already in channel ${WIFI_IFACE_CHANNEL} (${WIFI_IFACE_FREQ} MHz)"
-            echo "${WIFI_IFACE} already working in channel ${WIFI_IFACE_CHANNEL} (${WIFI_IFACE_FREQ} MHz)"
+            if is_5ghz_frequency $WIFI_IFACE_FREQ; then
-            
+                FREQ_BAND=5
-            if [[ $CHANNEL == default ]]; then
+            else
-                echo "Use wifi adapter current channel $WIFI_IFACE_CHANNEL as target channel"
+                FREQ_BAND=2.4
-                CHANNEL=$WIFI_IFACE_CHANNEL
             fi
-            
             if [[ $WIFI_IFACE_CHANNEL -ne $CHANNEL ]]; then
-                echo "WARN: Wifi adapter already working in channel ${WIFI_IFACE_CHANNEL}, which is different than target channel $CHANNEL" >&2
+                echo "Channel fallback to ${WIFI_IFACE_CHANNEL}"
+                CHANNEL=$WIFI_IFACE_CHANNEL
+            else
+                echo
             fi
         fi
 
@@ -1715,28 +1634,13 @@ prepare_wifi_interface() {
             echo "${VWIFI_IFACE} created"
         else
             VWIFI_IFACE=
-            if [[ ! -z ${VIRT_NAME} ]] && [[ ${#VIRT_NAME} -gt 15 ]]; then
-              die "Failed creating virtual WiFi interface. This is likely because you have set a long name for your virtual interface using --virt-name, try making it shorter'"
-            elif [[ -z ${VIRT_NAME} ]] && [[ ${#WIFI_IFACE} -gt 13 ]]; then
-              die "Failed creating virtual WiFi interface. This is likely because your interface name is too long. Try using '--virt-name <shorter interface name>'"
-            else
             die "Failed creating virtual WiFi interface. Maybe your WiFi adapter does not fully support virtual interfaces. Try again with '--no-virt'"
         fi
-        fi
         
         AP_IFACE=${VWIFI_IFACE}
     else # no virtual wifi interface, use wifi device interface itself
         AP_IFACE=${WIFI_IFACE}
     fi
-    
-    if [[ $CHANNEL == default ]]; then
-        echo "Channel not specified, use default"
-        if [[ $FREQ_BAND == 2.4 ]]; then
-            CHANNEL=1
-        else
-            CHANNEL=36
-        fi
-    fi
 }
 
 decide_subnet_interface() {
@@ -1798,10 +1702,6 @@ write_hostapd_conf() {
 		EOF
     fi
 
-    if [[ $HOTSPOT20 -eq 1 ]]; then
-        echo "hs20=1" >> "$CONFDIR/hostapd.conf"
-    fi
-
     if [[ $IEEE80211N -eq 1 ]]; then
         cat <<- EOF >> "$CONFDIR/hostapd.conf"
 			ieee80211n=1
@@ -1809,40 +1709,14 @@ write_hostapd_conf() {
 		EOF
     fi
 
-    if [[ $REQUIREHT -eq 1 ]]; then
-        echo "require_ht=1" >> "$CONFDIR/hostapd.conf"
-    fi
-
     if [[ $IEEE80211AC -eq 1 ]]; then
         echo "ieee80211ac=1" >> "$CONFDIR/hostapd.conf"
     fi
 
-    if [[ $REQUIREVHT -eq 1 ]]; then
-        echo "require_vht=1" >> "$CONFDIR/hostapd.conf"
-    fi
-
     if [[ -n "$VHT_CAPAB" ]]; then
         echo "vht_capab=${VHT_CAPAB}" >> "$CONFDIR/hostapd.conf"
     fi
 
-	if [[ $VHTCHANNELWIDTH -gt 0 ]]; then
-		cat <<- EOF >> "$CONFDIR/hostapd.conf"
-			vht_oper_chwidth=${VHTCHANNELWIDTH}
-		EOF
-	fi
-
-	if [[ $VHTSEG0CHINDEX -gt 0 ]]; then
-		cat <<- EOF >> "$CONFDIR/hostapd.conf"
-			vht_oper_centr_freq_seg0_idx=${VHTSEG0CHINDEX}
-		EOF
-	fi
-
-	if [[ $VHTSEG1CHINDEX -gt 0 ]]; then
-		cat <<- EOF >> "$CONFDIR/hostapd.conf"
-			vht_oper_centr_freq_seg1_idx=${VHTSEG1CHINDEX}
-		EOF
-	fi
-
     if [[ $IEEE80211N -eq 1 ]] || [[ $IEEE80211AC -eq 1 ]]; then
         echo "wmm_enabled=1" >> "$CONFDIR/hostapd.conf"
     fi
@@ -1936,10 +1810,6 @@ write_dnsmasq_conf() {
 			no-poll
 		EOF
     fi
-    if [[ $DNS_NOCACHE -eq 1 ]]; then
-        echo "cache-size=0" >> "$CONFDIR/dnsmasq.conf"
-        echo "no-negcache" >> "$CONFDIR/dnsmasq.conf"
-    fi
     if [[ $IPV6 -eq 1 ]];then
         cat <<- EOF  >> "$CONFDIR/dnsmasq.conf"
 			listen-address=${GATEWAY6}
@@ -2069,6 +1939,10 @@ phead
 phead2
 echo
 
+echo
+echo "This is workaround for #31. Must use with '-g' and for wired interface !"
+echo
+
 echo "PID: $$"
 
 TARGET_IFACE="$(decide_target_interface)" || exit 1 # judge wired (-i CONN_IFACE) or wireless hotspot (--ap $WIFI_IFACE)
@@ -2123,24 +1997,15 @@ fi
 [[ $NO_DNSMASQ -eq 0 ]] && write_dnsmasq_conf
 #===========================
 
-# initialize subnet interface
-# take subnet interface down first
-ip link set down dev ${SUBNET_IFACE} || die "Failed setting ${SUBNET_IFACE} down"
-# flush old IPs of subnet interface
-ip addr flush ${SUBNET_IFACE} || die "Failed flush ${SUBNET_IFACE} IP"
 
 dealwith_mac # setting MAC should be after setting NM unmanaged
 
 [[ $WIFI_IFACE ]] && check_rfkill_unblock_wifi
 
-# bring subnet interface up
-ip link set up dev ${SUBNET_IFACE} || die "Failed bringing ${SUBNET_IFACE} up"
 
 # hostapd , haveged
 [[ $WIFI_IFACE ]] && run_wifi_ap_processes
 
-# add ipv4 address to subnet interface
-ip -4 addr add ${GATEWAY}/24 broadcast ${GATEWAY%.*}.255 dev ${SUBNET_IFACE} || die "Failed setting ${SUBNET_IFACE} IPv4 address"
 
 set_ipv6_bits