-first netjail setup with NATs integrated

Signed-off-by: TheJackiMonster <thejackimonster@gmail.com>

contrib/scripts/netjail/netjail_core.sh

@@ -0,0 +1,100 @@
+#!/bin/sh
+# 
+
+JAILOR=${SUDO_USER:?must run in sudo}
+
+# running with `sudo` is required to be
+# able running the actual commands as the
+# original user.
+
+export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+
+netjail_check() {
+	NODE_COUNT=$1
+
+	FD_COUNT=$(($(ls /proc/self/fd | wc -w) - 4))
+
+	# quit if `$FD_COUNT < ($LOCAL_M * $GLOBAL_N * 2)`:
+	# the script also requires `sudo -C ($FD_COUNT + 4)`
+	# so you need 'Defaults closefrom_override' in the
+	# sudoers file.
+
+	if [ $FD_COUNT -lt $(($NODE_COUNT * 2)) ]; then
+		echo "File descriptors do not match requirements!" >&2
+		exit 1
+	fi
+}
+
+netjail_print_name() {
+	printf "%s%02x%02x" $1 $2 ${3:-0}
+}
+
+netjail_bridge() {
+	BRIDGE=$1
+
+	ip link add $BRIDGE type bridge
+	ip link set dev $BRIDGE up
+}
+
+netjail_bridge_clear() {
+	BRIDGE=$1
+
+	ip link delete $BRIDGE
+}
+
+netjail_node() {
+	NODE=$1
+
+	ip netns add $NODE
+}
+
+netjail_node_clear() {
+	NODE=$1
+
+	ip netns delete $NODE
+}
+
+netjail_node_link_bridge() {
+	NODE=$1
+	BRIDGE=$2
+	ADDRESS=$3
+	MASK=$4
+	
+	LINK_IF="$NODE-$BRIDGE-0"
+	LINK_BR="$NODE-$BRIDGE-1"
+
+	ip link add $LINK_IF type veth peer name $LINK_BR
+	ip link set $LINK_IF netns $NODE
+	ip link set $LINK_BR master $BRIDGE
+
+	ip -n $NODE addr add "$ADDRESS/$MASK" dev $LINK_IF
+	ip -n $NODE link set $LINK_IF up
+	ip -n $NODE link set up dev lo
+
+	ip link set $LINK_BR up
+}
+
+netjail_node_add_nat() {
+	NODE=$1
+	ADDRESS=$2
+	MASK=$3
+
+	ip netns exec $NODE iptables -t nat -A POSTROUTING -s "$ADDRESS/$MASK" -j MASQUERADE
+}
+
+netjail_node_add_default() {
+	NODE=$1
+	ADDRESS=$2
+
+	ip -n $NODE route add default via $ADDRESS
+}
+
+netjail_node_exec() {
+	NODE=$1
+	FD_IN=$2
+	FD_OUT=$3
+	shift 3
+
+	unshare -fp --kill-child -- ip netns exec $NODE sudo -u $JAILOR -- $@ 1>& $FD_OUT 0<& $FD_IN
+}
+

contrib/scripts/netjail/netjail_setup_internet.sh

@@ -0,0 +1,81 @@
+#!/bin/sh
+. "./netjail_core.sh"
+
+set -eu
+set -x
+
+export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
+
+LOCAL_M=$1
+GLOBAL_N=$2
+
+# TODO: stunserver? ..and globally known peer?
+
+shift 2
+
+netjail_check $(($LOCAL_M * $GLOBAL_N))
+
+LOCAL_GROUP="192.168.15"
+GLOBAL_GROUP="92.68.150"
+
+echo "Start [local: $LOCAL_GROUP.0/24, global: $GLOBAL_GROUP.0/24]"
+
+NETWORK_NET=$(netjail_print_name "n" $GLOBAL_N $LOCAL_M)
+
+netjail_bridge $NETWORK_NET
+
+for N in $(seq $GLOBAL_N); do
+	ROUTER=$(netjail_print_name "R" $N)
+
+	netjail_node $ROUTER 
+	netjail_node_link_bridge $ROUTER $NETWORK_NET "$GLOBAL_GROUP.$N" 24
+
+	ROUTER_NET=$(netjail_print_name "r" $N)
+
+	netjail_bridge $ROUTER_NET
+	
+	for M in $(seq $LOCAL_M); do
+		NODE=$(netjail_print_name "N" $N $M)
+
+		netjail_node $NODE
+		netjail_node_link_bridge $NODE $ROUTER_NET "$LOCAL_GROUP.$M" 24
+	done
+
+	ROUTER_ADDR="$LOCAL_GROUP.$(($LOCAL_M+1))"
+
+	netjail_node_link_bridge $ROUTER $ROUTER_NET $ROUTER_ADDR 24
+	netjail_node_add_nat $ROUTER $ROUTER_ADDR 24
+	
+	for M in $(seq $LOCAL_M); do
+		NODE=$(netjail_print_name "N" $N $M)
+		
+		netjail_node_add_default $NODE $ROUTER_ADDR
+	done
+done
+
+for N in $(seq $GLOBAL_N); do
+	for M in $(seq $LOCAL_M); do
+		NODE=$(netjail_print_name "N" $N $M)
+		INDEX=$(($LOCAL_M * ($N - 1) + $M - 1))
+
+		FD_X=$(($INDEX * 2 + 3 + 0))
+		FD_Y=$(($INDEX * 2 + 3 + 1))
+
+		netjail_node_exec $NODE $FD_X $FD_Y $@ &
+	done
+done
+
+wait
+
+for N in $(seq $GLOBAL_N); do
+	for M in $(seq $LOCAL_M); do
+		netjail_node_clear $(netjail_print_name "N" $N $M)
+	done
+	
+	netjail_bridge_clear $(netjail_print_name "r" $N)
+	netjail_node_clear $(netjail_print_name "R" $N)
+done
+
+netjail_bridge_clear $NETWORK_NET
+
+echo "Done"