#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
#
# Testing For TCP/UDP/SCTP(4/6) NAT.
# TOPO: CLIENT_NS (link0)<--->(link1) HOST/ROUTER (link2)<--->(link3) SERVER_NS

CLIENT_NS="client-ns"
CLIENT_IP4="198.51.100.1"
CLIENT_GW4="198.51.100.2"
CLIENT_IP6="2001:db8:1::1"
CLIENT_GW6="2001:db8:1::2"

SERVER_NS="server-ns"
SERVER_IP4="203.0.113.1"
SERVER_GW4="203.0.113.2"
SERVER_IP6="2001:db8:2::1"
SERVER_GW6="2001:db8:2::2"

setup() {
	ip netns add $CLIENT_NS
	ip netns add $SERVER_NS
	ip link add link1 type veth peer name link0 netns $CLIENT_NS
	ip link add link2 type veth peer name link3 netns $SERVER_NS

	ip net exec $CLIENT_NS ip link set link0 up
	ip net exec $CLIENT_NS ip addr add $CLIENT_IP4/24 dev link0
	ip net exec $CLIENT_NS ip addr add $CLIENT_IP6/64 dev link0 nodad
	ip net exec $CLIENT_NS ip route add $SERVER_IP4 dev link0 via $CLIENT_GW4
	ip net exec $CLIENT_NS ip route add $SERVER_IP6 dev link0 via $CLIENT_GW6

	ip link set link1 up
	ip link set link2 up
	ip addr add $CLIENT_GW4/24 dev link1
	ip addr add $CLIENT_GW6/64 dev link1 nodad
	ip addr add $SERVER_GW4/24 dev link2
	ip addr add $SERVER_GW6/64 dev link2 nodad
	iptables -t nat -A POSTROUTING -o link2 -j MASQUERADE
	ip6tables -t nat -A POSTROUTING -o link2 -j MASQUERADE

	ip net exec $SERVER_NS ip link set link3 up
	ip net exec $SERVER_NS ip addr add $SERVER_IP4/24 dev link3
	ip net exec $SERVER_NS ip addr add $SERVER_IP6/64 dev link3 nodad

	IP4_FWD=`cat /proc/sys/net/ipv4/ip_forward`
	IP6_FWD=`cat /proc/sys/net/ipv6/conf/all/forwarding`
	sysctl -w net.ipv4.ip_forward=1 2>&1 >/dev/null
	sysctl -w net.ipv6.conf.all.forwarding=1 2>&1 >/dev/null
	modprobe sctp
}

cleanup() {
	sysctl -w net.ipv4.ip_forward=$IP4_FWD 2>&1 >/dev/null
	sysctl -w net.ipv6.conf.all.forwarding=$IP6_FWD 2>&1 >/dev/null
	ip link del link1
	ip link del link2
	ip netns del "$CLIENT_NS"
	ip netns del "$SERVER_NS"
}

testup() {
	local ipaddr="$1"
	local proto="$2"

	ip net exec $SERVER_NS nc -l $proto -p 1234 2>&1 >/dev/null &
	disown
	echo -n "msg1" | ip net exec $CLIENT_NS nc $ipaddr 1234 -p 4321 $proto

	ip net exec $SERVER_NS nc -l $proto -p 1234 2>&1 >/dev/null &
	disown
	echo -n "msg2" | ip net exec $CLIENT_NS nc $ipaddr 1234 -p 4321 $proto

	RET=$?
	ip net exec $SERVER_NS pkill nc
	return $RET
}

if ! nc --version &> /dev/null; then
	echo "SKIP: Could not run test without nc tool"
	exit 4
fi

trap cleanup EXIT
setup &&
testup $SERVER_IP4 && echo "TCP4 NAT: PASS" &&
testup $SERVER_IP6 && echo "TCP6 NAT: PASS" &&
testup $SERVER_IP4 "--udp" && echo "UDP4 NAT: PASS" &&
testup $SERVER_IP6 "--udp" && echo "UDP6 NAT: PASS" &&
testup $SERVER_IP4 "--sctp" && echo "SCTP4 NAT: PASS" &&
testup $SERVER_IP6 "--sctp" && echo "SCTP6 NAT: PASS"
exit $?