Initial commit

part1.sh

+#/bin/bash
+
+ssh R1 << 'EOF'
+
+apt update && apt install -y tcpdump
+
+echo 1 > /proc/sys/net/ipv4/ip_forward
+
+dhclient -v eth0
+
+ip addr add 10.0.0.1/24 dev eth1
+
+ip link set eth1 up
+
+cat > /root/nat.nft << 'ENDNAT'
+#!/usr/sbin/nft -f
+
+flush ruleset
+
+table ip nat {
+	chain masq {
+		type nat hook postrouting priority 100;
+		oifname "eth0" counter masquerade
+	}
+}
+ENDNAT
+
+nft -f /root/nat.nft
+EOF
+
+ssh H1 << 'EOF'
+
+apt update && install -y tcpdump
+
+ip addr add 10.0.0.2/24 dev eth0
+ 
+ip link set eth0 up
+
+ip route add default via 10.0.0.1 dev eth0
+EOF

part2.sh

+#!/bin/bash
+
+ssh R1 << 'EOF'
+
+set -e
+
+ip netns del ns2 2>/dev/null || true
+ip link del veth0 2>/dev/null || true
+ip link del veth1 2>/dev/null || true
+
+
+ip netns add ns2
+
+ip link add veth1 type veth peer name veth1-ns
+ip link add veth0 type veth peer name veth0-ns
+
+ip link set veth1-ns netns ns2
+ip link set veth0-ns netns ns2
+
+ip link set veth1 up
+ip link set veth0 up
+
+
+ip netns exec ns2 ip link set lo up
+ip netns exec ns2 ip link set veth1-ns name veth1
+ip netns exec ns2 ip link set veth0-ns name veth0
+ip netns exec ns2 ip link set veth1 up
+ip netns exec ns2 ip link set veth0 up
+
+ip addr add 192.168.1.1/24 dev veth1
+ip netns exec ns2 ip addr add 192.168.1.2/24 dev veth1
+
+ip addr add 192.168.0.1/24 dev veth0
+ip netns exec ns2 ip addr add 192.168.0.2/24 dev veth0
+
+ip netns exec ns2  echo 1 > /proc/sys/net/ipv4/ip_forward
+
+ip netns exec ns2 bash -c cat > /root/nat-r2.nft << 'ENDNAT'
+
+flush ruleset
+
+table ip nat {
+	chain masq {
+		type nat hook postrouting priority 100;
+		oifname "veth0" counter masquerade
+	}
+}
+ENDNAT
+
+nft -f /root/nat-r2.nft
+
+ip netns exec ns2 ip route add 10.0.0.0/24 via 192.168.1.1
+ip netns exec ns2 ip route add default via 192.168.0.1
+
+ip route delete default || true
+ip route add default via 192.168.1.1
+
+echo 100 custom >> /etc/iproute2/rt_tables
+ip rule add iif veth0 table custom
+ip route add default via 172.21.1.1 table custom
+
+EOF

part3.sh

+#!/bin/bash
+
+ssh H1 << 'EOF'
+set -e
+
+ip addr flush dev eth0
+ip addr add 10.0.0.2/24 dev eth0
+ip link set eth0 up
+
+ip route del default 2>/dev/null || true
+ip route add default via 10.0.0.254
+
+EOF
+
+ssh R1 << 'EOF'
+set -e
+
+ip netns del ns2 2>/dev/null || true
+ip link del br0 2>/dev/null || true
+ip link del br1 2>/dev/null || true
+ip link del veth1 2>/dev/null || true
+ip link del veth0 2>/dev/null || true
+
+nft flush ruleset 2>/dev/null || true
+
+ip link add br0 type bridge
+ip link set br0 up
+
+ip link add br1 type bridge
+ip link set br1 up
+
+
+ip link add veth0 type veth peer name veth0-ns
+ip link add veth1 type veth peer name veth1-ns
+
+ip netns add ns2
+ip link set veth0-ns netns ns2
+ip link set veth1-ns netns ns2
+
+ip link set eth0 up
+ip link set eth0 master br0
+
+ip link set eth1 up
+ip link set eth1 master br1
+
+ip link set veth0 up
+ip link set veth0 master br0
+
+ip link set veth1 up
+ip link set veth1 master br1
+
+ip netns exec ns2 ip link set veth0-ns name eth0
+ip netns exec ns2 ip link set eth0 up
+
+ip netns exec ns2 ip link set veth1-ns name eth1
+ip netns exec ns2 ip link set eth1 up
+
+ip addr add 172.21.1.100/24 dev br0
+ip addr add 10.0.0.254/24 dev br1
+
+ip netns exec ns2  echo 1 > /proc/sys/net/ipv4/ip_forward
+
+ip route del default via 172.21.1.1 dev br0 2>/dev/null || true
+ip route add default via 172.21.1.1 dev br0
+
+ip netns exec ns2 bash -c cat > /root/nat-r2.nft << 'ENDNFT'
+#!/usr/sbin/nft -f
+flush ruleset
+
+table ip nat {
+    chain masq {
+        type nat hook postrouting priority 100;
+        oifname "br0" counter masquerade
+    }
+}
+ENDNFT
+
+nft -f /root/nat-r2.nft
+EOF
\ No newline at end of file

part4.sh

+#!/bin/bash
+
+ssh -tt H1 << 'EOF'
+set -e
+
+ip addr flush dev eth0
+ip addr add 10.0.0.2/24 dev eth0
+ip link set eth0 up
+
+ip route del default 2>/dev/null || true
+ip route add default via 10.0.0.254
+
+EOF
+
+ssh -tt R1 << 'EOF'
+set -e
+
+ip netns add ns2
+ip netns add ns3
+
+ip link add br0 type bridge
+ip link set br0 up
+
+ip link add br1 type bridge
+ip link set br1 up
+
+ip addr add 172.21.1.100/24 dev br0
+ip addr add 10.0.0.254/24 dev br1
+
+ip link set eth1 up
+ip link set eth1 master br1
+
+ip link set eth0 up
+ip link set eth0 master br0
+
+ip link add veth0-r1 type veth peer name veth0-ns2
+ip link add veth1-r1 type veth peer name veth0-ns3
+ip link add veth1-ns2 type veth peer name veth1-ns3
+
+ip link set veth0-r1 up
+ip link set veth0-r1 master br0
+
+ip link set veth1-r1 up
+ip link set veth1-r1 master br1
+
+ip link set veth0-ns2 netns ns2
+ip link set veth1-ns2 netns ns2
+
+ip link set veth0-ns3 netns ns3
+ip link set veth1-ns3 netns ns3
+
+# -----------------------------------------------
+
+ip netns exec ns3 ip link set veth0-ns3 name eth0
+ip netns exec ns3 ip link set veth1-ns3 name eth1
+
+ip netns exec ns3 ip link set eth0 up
+ip netns exec ns3 ip link set eth1 up
+
+ip netns exec ns3 ip addr add 192.168.32.2/24 dev eth1
+ip netns exec ns3 ip addr add 10.0.0.254/24 dev eth0
+
+ip netns exec ns3 ip route add default via 192.168.32.1 dev eth1
+
+# ------------------------------------------------
+
+ip netns exec ns2 ip link set veth0-ns2 name eth0
+ip netns exec ns2 ip link set veth1-ns2 name eth1
+
+ip netns exec ns2 ip link set eth0 up
+ip netns exec ns2 ip link set eth1 up
+
+ip netns exec ns2 ip addr add 192.168.32.1/24 dev eth1
+ip netns exec ns2 ip addr add 172.21.1.100/24 dev eth0
+
+ip netns exec ns2 ip route add 10.0.0.0/24 via 192.168.32.2 dev eth1
+ip netns exec ns2 ip route add default via 172.21.1.1 dev eth0
+
+# --------------------------------------------------
+
+ip netns exec ns2  echo 1 > /proc/sys/net/ipv4/ip_forward
+ip netns exec ns3  echo 1 > /proc/sys/net/ipv4/ip_forward
+
+ip netns exec ns2 bash -c cat > /root/nat-r2.nft << 'ENDNFT'
+#!/usr/sbin/nft -f
+flush ruleset
+
+table ip nat {
+    chain masq {
+        type nat hook postrouting priority 100;
+        oifname "br0" counter masquerade
+    }
+}
+ENDNFT
+
+nft -f /root/nat-r2.nft
+EOF
\ No newline at end of file