wireguard-tools/contrib/ncat-client-server/client.sh

#!/bin/bash
set -e
[[ $UID == 0 ]] || { echo "You must be root to run this."; exit 1; }
umask 077
trap 'rm -f /tmp/wg_private_key' EXIT INT TERM
exec 3<>/dev/tcp/demo.wireguard.io/42912
wg genkey | tee /tmp/wg_private_key | wg pubkey >&3
IFS=: read -r status server_pubkey server_port internal_ip <&3
[[ $status == OK ]]
ip link del dev wg0 2>/dev/null || true
ip link add dev wg0 type wireguard
wg set wg0 private-key /tmp/wg_private_key peer "$server_pubkey" allowed-ips 0.0.0.0/0 endpoint "demo.wireguard.io:$server_port" persistent-keepalive 25
ip address add "$internal_ip"/24 dev wg0
ip link set up dev wg0
if [ "$1" == "default-route" ]; then
	host="$(wg show wg0 endpoints | sed -n 's/.*\t\(.*\):.*/\1/p')"
	ip route add $(ip route get $host | sed '/ via [0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}/{s/^\(.* via [0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\).*/\1/}' | head -n 1) 2>/dev/null || true
	ip route add 0/1 dev wg0
	ip route add 128/1 dev wg0
fi