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FROM alpine:3.17

RUN apk add --no-cache \
    bash \
    bind-tools \
    iptables \
    ip6tables \
    openvpn

COPY . /usr/local/bin

ENV KILL_SWITCH=on

ENTRYPOINT [ "entry.sh" ]

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#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

# Block all traffic not going through tun0 interface
iptables --insert OUTPUT \
    ! --out-interface tun0 \
    --match addrtype ! --dst-type LOCAL \
    ! --destination "$(ip -4 -oneline addr show dev eth0 | awk 'NR == 1 { print $4 }')" \
    --jump REJECT

# Create static routes for allowed subnets
default_gateway=$(ip -4 route | awk '$1 == "default" { print $3 }')
for subnet in ${1//,/ }; do
    ip route add "$subnet" via "$default_gateway"
    iptables --insert OUTPUT --destination "$subnet" --jump ACCEPT
done

# Whitelist OpenVPN server addresses
global_port=$(awk '$1 == "port" { print $2 }' "${config:?"config file not found by kill switch"}")
global_protocol=$(awk '$1 == "proto" { print $2 }' "${config:?"config file not found by kill switch"}")
remotes=$(awk '$1 == "remote" { print $2, $3, $4 }' "${config:?"config file not found by kill switch"}")
ip_regex='^(([1-9]?[0-9]|1[0-9][0-9]|2([0-4][0-9]|5[0-5]))\.){3}([1-9]?[0-9]|1[0-9][0-9]|2([0-4][0-9]|5[0-5]))$'
while IFS= read -r line; do
    # Process each remote entry
    IFS=" " read -ra remote <<< "${line%%\#*}"
    address=${remote[0]}
    port=${remote[1]:-${global_port:-1194}}
    protocol=${remote[2]:-${global_protocol:-udp}}

    # Allow IP addresses and handle domain resolution
    if [[ $address =~ $ip_regex ]]; then
        iptables --insert OUTPUT --destination "$address" --protocol "$protocol" --destination-port "$port" --jump ACCEPT
    else
        for ip in $(dig -4 +short "$address"); do
            iptables --insert OUTPUT --destination "$ip" --protocol "$protocol" --destination-port "$port" --jump ACCEPT
            echo "$ip $address" >> /etc/hosts
        done
    fi
done <<< "$remotes"

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#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

cleanup() {
    kill TERM "$openvpn_pid"
    exit 0
}

is_enabled() {
    [[ ${1,,} =~ ^(true|t|yes|y|1|on|enable|enabled)$ ]]
}

# Either a specific file name or a pattern.
if [[ $CONFIG_FILE ]]; then
    config_file=$(find /config -name "$CONFIG_FILE" 2> /dev/null | sort | shuf -n 1)
else
    config_file=$(find /config -name '*.conf' -o -name '*.ovpn' 2> /dev/null | sort | shuf -n 1)
fi

if [[ -z $config_file ]]; then
    echo "no openvpn configuration file found" >&2
    exit 1
fi

echo "using openvpn configuration file: $config_file"

openvpn_args=(
    "--config" "$config_file"
    "--cd" "/config"
)

if is_enabled "$KILL_SWITCH"; then
    openvpn_args+=("--route-up" "/usr/local/bin/killswitch.sh $ALLOWED_SUBNETS")
fi

# Docker secret that contains the credentials for accessing the VPN.
if [[ $AUTH_SECRET ]]; then
    openvpn_args+=("--auth-user-pass" "/run/secrets/$AUTH_SECRET")
fi

openvpn "${openvpn_args[@]}" &
openvpn_pid=$!

trap cleanup TERM

wait $openvpn_pid

1

  docker compose build

1

  docker compose up -d

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services:
  openvpn-client:
    image: openvpn-client:latest  # ghcr.io/wfg/openvpn-client
    build:
      context: ./
      dockerfile: Dockerfile
    container_name: openvpn-client
    cap_add:
      - NET_ADMIN
    environment:
      # - HTTP_PROXY=on
      - SOCKS_PROXY=on
    devices:
      - /dev/net/tun:/dev/net/tun
    volumes:
      - ./local:/config
      - ./local:/data/vpn
    ports:
      # - 8080:8080  # HTTP_PROXY port
      - 1080:1080  # SOCKS_PROXY port
    restart: unless-stopped

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proxies:
	- { name: OpenVPN, server: 127.0.0.1, port: 1080, type: socks5 }

rules:
	- IP-CIDR,192.168.142.0/24,OpenVPN
	- IP-CIDR,10.10.10.0/24,OpenVPN
	- IP-CIDR,172.16.0.0/24,OpenVPN

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    - { name: 'CNKI', type: socks5, server: 10.10.10.45, port: 57080}
    - 'DOMAIN-SUFFIX,cnki.net,CNKI'