android_direct.sh

#!/bin/sh

PROXY_HOST=$(ifconfig en0 | grep "inet " | awk '{print $2}')
PROXY_PORT=8080

function adb_shell {
  cmd="$1"
  adb shell "${cmd}"
}

function sh_sudo {
  cmd="$1"
  adb_shell "/system/bin/su -c \"${cmd}\""
}

function enable_forward {
  sh_sudo "echo 1 > /proc/sys/net/ipv4/ip_forward"
}

function disable_forward {
  sh_sudo "echo 0 > /proc/sys/net/ipv4/ip_forward"
}

function redirect_port {
  dport=$1
  proxy_host=$2
  proxy_port=$3
  sh_sudo "iptables -t nat -A PREROUTING -p tcp --dport ${dport} -j DNAT --to-destination ${proxy_host}:${proxy_port}"
}

function iptable_flush {
  sh_sudo "iptables --flush"
}
# test
iptable_flush
enable_forward
redirect_port 80 ${PROXY_HOST} ${PROXY_PORT}
redirect_port 443 ${PROXY_HOST} ${PROXY_PORT}