#!/bin/bash

# First, let's identify your network interfaces
ip addr show

# Create a new routing table for the second interface
echo "200 steam2" >> /etc/iproute2/rt_tables

# Assuming eth0 is your ethernet and wlan0 is your WiFi
# Replace these with your actual interface names from ip addr show
ETH="eth0"
WIFI="wlan0"

# Get the gateway IPs for both interfaces
ETH_GATEWAY=$(ip route show dev $ETH | grep default | awk '{print $3}')
WIFI_GATEWAY=$(ip route show dev $WIFI | grep default | awk '{print $3}')

# Add routes for the second interface
ip route add default via $WIFI_GATEWAY dev $WIFI table steam2

# Add rules to use both routing tables
ip rule add from $(ip addr show dev $ETH | grep inet | awk '{print $2}') table main
ip rule add from $(ip addr show dev $WIFI | grep inet | awk '{print $2}') table steam2

# Enable IP forwarding
echo 1 > /proc/sys/net/ipv4/ip_forward

# Configure source routing
cat > /etc/sysctl.d/90-steam-routing.conf << EOF
net.ipv4.conf.all.rp_filter=2
net.ipv4.conf.default.rp_filter=2
net.ipv4.conf.$ETH.rp_filter=2
net.ipv4.conf.$WIFI.rp_filter=2
EOF

# Apply sysctl settings
sysctl -p /etc/sysctl.d/90-steam-routing.conf

# Save the current iptables rules
iptables-save > /root/iptables.backup

# Add marking rules for Steam traffic
iptables -t mangle -A OUTPUT -p tcp --dport 27015:27050 -j MARK --set-mark 0x2
iptables -t mangle -A OUTPUT -p udp --dport 27015:27050 -j MARK --set-mark 0x2

# Save the new iptables rules
iptables-save > /etc/iptables/rules.v4