Making a network gateway with a transparent proxy in v2ray docker image

.github/workflows/docker-push.yml

@@ -6,12 +6,14 @@ on:
   push:
     paths:
       - "v2ray.sh"
+      - "entrypoint.sh"
       - "Dockerfile"
       - ".github/workflows/docker-push.yml"
   pull_request:
     types: [opened, synchronize, reopened]
     paths:
       - "v2ray.sh"
+      - "entrypoint.sh"
       - "Dockerfile"
       - ".github/workflows/docker-push.yml"
 

Dockerfile

@@ -1,6 +1,8 @@
 FROM --platform=${TARGETPLATFORM} alpine:latest
 LABEL maintainer="V2Fly Community <dev@v2fly.org>"
 
+RUN apk add iptables
+
 WORKDIR /root
 ARG TARGETPLATFORM
 ARG TAG
@@ -15,4 +17,11 @@ RUN set -ex \
     && chmod +x /root/v2ray.sh \
     && /root/v2ray.sh "${TARGETPLATFORM}" "${TAG}"
 
-ENTRYPOINT ["/usr/bin/v2ray"]
+COPY entrypoint.sh /root/entrypoint.sh
+RUN chmod +x /root/entrypoint.sh
+
+ENV TPROXY false
+ENV DOKODEMO_DOOR_PORT 12345
+ENV BYPASS_SUBNETS ""
+
+ENTRYPOINT ["/root/entrypoint.sh"]

README.md

@@ -12,4 +12,203 @@ docker run --rm v2fly/v2fly-core help
 docker run --name v2ray v2fly/v2fly-core $v2ray_args (help, eun etc...)
 
 docker run -d --name v2ray -v /path/to/config.json:/etc/v2fly/config.json -p 10086:10086 v2fly/v2fly-core run -c /etc/v2fly/config.json 
+```
+---
+# Gateway mode
+You can use v2ray as a network gateway for serving a proxied network to another container or other devices in the network. 
+
+For running the container in gateway mode you need to make some changes in you v2ray config file.
+
+1. Add an additional inbound with the dokodemo-door protocol for listening on the 12345 port (like example)
+2. Add a mark of 255 to all the outbounds
+
+### Example of config file for gateway mode
+```json
+{
+  "inbounds": [
+    {
+      "port": 1080, 
+      "protocol": "socks",
+      "sniffing": {
+        "enabled": true,
+        "destOverride": ["http", "tls"]
+      },
+      "settings": {
+        "auth": "noauth"
+      }
+    }, 
+    {
+      "tag":"transparent",
+      "port": 12345,
+      "protocol": "dokodemo-door",
+      "settings": {
+        "network": "tcp,udp",
+        "followRedirect": true
+      },
+      "sniffing": {
+        "enabled": true,
+        "destOverride": [
+          "http",
+          "tls"
+        ]
+      },
+      "streamSettings": {  // it's necessary
+        "sockopt": {
+          "tproxy": "tproxy",
+          "mark":255
+        }
+      }
+    }
+  ],
+  "outbounds": [
+    {
+      "tag": "proxy-1",
+      "protocol": "vmess",
+      "settings": {
+        "vnext": [
+          ...
+        ]
+      },
+      "streamSettings": {  
+        "sockopt": {        // You should add these settings for all of the outbounds
+          "mark": 255
+        }
+      }
+    },
+    {
+      "tag": "direct",
+      "protocol": "freedom",
+      "settings": {
+        "domainStrategy": "UseIP"
+      },
+      "streamSettings": {
+        "sockopt": {        // Even for freedom 
+          "mark": 255
+        }
+      }      
+    },
+    {
+      "tag": "block",
+      "protocol": "blackhole",
+      "settings": {
+        "response": {
+          "type": "http"
+        }
+      }
+    },
+    {
+      "tag": "dns-out",
+      "protocol": "dns",
+      "streamSettings": {
+        "sockopt": {
+          "mark": 255
+        }
+      }  
+    }
+  ],
+  "dns": {
+    "servers": [
+      ...
+    ]
+  },
+  "routing": {
+    "domainStrategy": "IPOnDemand",
+    "rules": [
+      {
+        "type": "field",
+        "inboundTag": [
+          "transparent"
+        ],
+        "port": 53,
+        "network": "udp",
+        "outboundTag": "dns-out" 
+      },    
+      { // Directly connect to port 123 UDP traffic (NTP protocol)
+        "type": "field",
+        "inboundTag": [
+          "transparent"
+        ],
+        "port": 123,
+        "network": "udp",
+        "outboundTag": "direct" 
+      },    
+      ...
+    ]
+  }
+}
+
+```
+
+Please read [this topic](https://guide.v2fly.org/app/tproxy.html) for more details.
+
+
+### Example of a home network gateway with docker compose
+```yaml
+version: '3.4'
+services:
+  v2ray:
+    image: v2fly/v2fly-core
+    cap_add:
+      - NET_ADMIN # Required in gateway mode
+    volumes:
+      - ./testConfig.json:/etc/v2ray/config.json
+    environment:
+      - TPROXY=true # Active the gateway mode
+    command: ['run','-c','/etc/v2ray/config.json']
+    networks:
+      vlan:
+        ipv4_address: 192.168.1.254 # The IP address of this container which other devices can use this IP as a gateway.
+
+networks:
+  vlan:
+    driver: macvlan
+    driver_opts:
+      parent: ens3 # The ethernet adaptor in the host system 
+    ipam:
+      driver: default
+      config:
+        - subnet: 192.168.1.0/24  # Home network subnet
+          gateway: 192.168.1.1 # Home network gateway (your router ip)
+
+```
+
+
+###  Example of a gateway for other containers with docker compose
+```yaml
+version: '3.4'
+services:
+  v2ray:
+    image: v2fly/v2fly-core
+    cap_add:
+      - NET_ADMIN # Required in gateway mode
+    volumes:
+      - ./testConfig.json:/etc/v2ray/config.json
+    environment:
+      - TPROXY=true # Active the gateway mode
+    command: ['run','-c','/etc/v2ray/config.json']
+    networks:
+      bridgenetwork:
+        ipv4_address: 192.168.30.1
+
+  test-conatiner:
+    image: weibeld/ubuntu-networking
+    depends_on:
+      - v2ray
+    stdin_open: true
+    privileged: true
+    networks:
+      bridgenetwork:
+
+    command: >          # Adding the v2ray container IP as a default gateway
+      sh -c "ip route del default &&
+      ip route add default via 192.168.30.1 &&
+      tail -f /dev/null"
+networks:
+  bridgenetwork:
+    driver: bridge
+    ipam:
+      driver: default
+      config:
+        - subnet: "192.168.30.0/24"
+          gateway: "192.168.30.254"
 ```

entrypoint.sh

@@ -0,0 +1,72 @@
+#!/bin/sh
+
+
+setupTProxy() { 
+
+    local docker_network="$(ip -o addr show dev eth0 | awk '$3 == "inet" {print $4}')"
+    local default_gateway=$(ip -4 route | grep 'default via' | awk '{print $3}')
+    local dokodemo_port=12345
+
+    if [[ $DOKODEMO_DOOR_PORT ]]; then
+        dokodemo_port=$DOKODEMO_DOOR_PORT
+    fi
+
+    echo "
+--- Setting up the gateway iptables rules ----
+        dokodemo-door port: ${dokodemo_port}
+        Bypassed subnets: ${docker_network}, ${BYPASS_SUBNETS}
+        Default gateway: ${default_gateway}
+Pay attention: This gateway handles the TCP and UDP requests. The Dokodemo-door doesn't support ICMP packets!"
+
+    # Reference: https://guide.v2fly.org/app/tproxy.html#%E8%AE%BE%E7%BD%AE%E7%BD%91%E5%85%B3
+    # Set policy routing
+    ip rule add fwmark 1 table 100 
+    ip route add local 0.0.0.0/0 dev lo table 100
+    # Proxy LAN device
+    iptables -t mangle -N V2RAY
+    iptables -t mangle -A V2RAY -d 127.0.0.1/24 -j RETURN
+    iptables -t mangle -A V2RAY -d 224.0.0.0/4 -j RETURN 
+    iptables -t mangle -A V2RAY -d 255.255.255.255/32 -j RETURN 
+    iptables -t mangle -A V2RAY -d ${docker_network} -p tcp -j RETURN # Directly connect to the LAN to avoid SSH that cannot connect to the gateway when V2Ray cannot be started. If you configure other network segments (such as 10.x.x.x, etc.), modify it to your own
+    iptables -t mangle -A V2RAY -d ${docker_network} -p udp ! --dport 53 -j RETURN # Directly connected to the LAN, except port 53 (because V2Ray's DNS is used)
+    if [[ $BYPASS_SUBNETS ]]; then
+        for subnet in ${BYPASS_SUBNETS//,/ }; do
+            iptables -t mangle -A V2RAY -d "$subnet" -p tcp -j RETURN 
+            iptables -t mangle -A V2RAY -d "$subnet" -p udp ! --dport 53 -j RETURN 
+        done
+    fi
+    iptables -t mangle -A V2RAY -j RETURN -m mark --mark 0xff    # Directly connect to the traffic whose SO_MARK is 0xff (0xff is a hexadecimal number, which is equivalent to 255 in the above V2Ray configuration). The purpose of this rule is to solve the problem that v2ray takes up a lot of CPU（https://github.com/v2ray/v2ray-core/issues/2621）
+    iptables -t mangle -A V2RAY -p udp -j TPROXY --on-ip 127.0.0.1 --on-port ${dokodemo_port} --tproxy-mark 1 # Mark UDP as 1 and forward to port 12345
+    iptables -t mangle -A V2RAY -p tcp -j TPROXY --on-ip 127.0.0.1 --on-port ${dokodemo_port} --tproxy-mark 1 # Mark the TCP with 1 and forward it to port 12345
+    iptables -t mangle -A PREROUTING -j V2RAY # application rules
+
+    # proxy gateway native
+    iptables -t mangle -N V2RAY_MASK 
+    iptables -t mangle -A V2RAY_MASK -d 224.0.0.0/4 -j RETURN 
+    iptables -t mangle -A V2RAY_MASK -d 255.255.255.255/32 -j RETURN 
+    iptables -t mangle -A V2RAY_MASK -d ${docker_network} -p tcp -j RETURN # Direct LAN
+    iptables -t mangle -A V2RAY_MASK -d ${docker_network} -p udp ! --dport 53 -j RETURN # Directly connected to LAN, except port 53 (because V2Ray's DNS is used)
+    if [[ $BYPASS_SUBNETS ]]; then
+        for subnet in ${BYPASS_SUBNETS//,/ }; do
+            iptables -t mangle -A V2RAY_MASK -d "$subnet" -p tcp -j RETURN # Direct LAN
+            iptables -t mangle -A V2RAY_MASK -d "$subnet" -p udp ! --dport 53 -j RETURN # Directly connected to LAN, except port 53 (because V2Ray's DNS is used)
+        done
+    fi
+    iptables -t mangle -A V2RAY_MASK -j RETURN -m mark --mark 0xff    # Directly connect to traffic whose SO_MARK is 0xff (0xff is a hexadecimal number, which is equivalent to 255 in the above V2Ray configuration). The purpose of this rule is to avoid the loopback problem of proxy local (gateway) traffic
+    iptables -t mangle -A V2RAY_MASK -p udp -j MARK --set-mark 1   # Mark UDP, reroute
+    iptables -t mangle -A V2RAY_MASK -p tcp -j MARK --set-mark 1   # Mark TCP, reroute
+    iptables -t mangle -A OUTPUT -j V2RAY_MASK # application rules
+
+    # Create a new DIVERT rule to prevent existing connected packets from passing through TPROXY twice, theoretically, there is a certain performance improvement
+    iptables -t mangle -N DIVERT
+    iptables -t mangle -A DIVERT -j MARK --set-mark 1
+    iptables -t mangle -A DIVERT -j ACCEPT
+    iptables -t mangle -I PREROUTING -p tcp -m socket -j DIVERT
+}
+
+
+if [[ "$TPROXY" = "true" ]]; then
+    setupTProxy &
+fi
+
+/usr/bin/v2ray "$@"