Merge pull request 'readme with scripts' (#4) from readme into develop

Reviewed-on: #4

Makefile

@@ -1,7 +1,7 @@
 manual:
 	docker run --rm -v /tmp:/tmp -v ${PWD}:/app -w /app golang:1.15-buster go build -o /tmp/mpbl3p
-	rsync -p /tmp/mpbl3p 10.21.12.101:
-	rsync -p /tmp/mpbl3p 10.21.12.102:
+	rsync -p /tmp/mpbl3p 10.21.10.3:
+	rsync -p /tmp/mpbl3p 10.21.10.4:
 
 manual-bsd:
 	GOOS=freebsd go build -o /tmp/mpbl3p

README.md

@@ -4,15 +4,84 @@
 ### Linux
 #### Policy Based Routing
 
-    ip route flush 11
-    ip route add table 11 to 1.1.1.0/24 dev eth1
-    ip rule add from 1.1.1.4 table 11 priority 11
-    
     ip route flush 10
-    ip route add table 10 to 1.1.1.0/24 dev eth2
-    ip rule add from 1.1.1.5 table 10 priority 10
+    ip route add table 10 to 1.1.1.0/24 dev eth1
+    ip rule add from 1.1.1.4 table 10 priority 10
+
+    ip route flush 11
+    ip route add table 11 to 1.1.1.0/24 dev eth2
+    ip rule add from 1.1.1.5 table 11 priority 11
 
 #### ARP Flux
 
     sysctl -w net.ipv4.conf.all.arp_announce=1
-    sysctl -w net.ipv4.conf.all.arp_ignore=2
+    sysctl -w net.ipv4.conf.all.arp_ignore=1
+    
+See http://kb.linuxvirtualserver.org/wiki/Using_arp_announce/arp_ignore_to_disable_ARP
+    
+### Setup Scripts
+These are functional setup scripts that make the application run as intended on Linux. They should later be split into
+component parts, or incorporated into the main application.
+
+#### Remote Portal
+
+    #!/bin/bash
+    set -e
+    
+    # IPv4 Forwarding
+    sysctl -w net.ipv4.ip_forward=1
+    
+    # Tunnel addr/up
+    ip addr add 172.19.152.2/31 dev nc0
+    ip link set up nc0
+    
+    # Deliberately break local routing
+    ip rule add from all table local priority 20
+    ip rule del 0 || true
+    
+    # Route packets to the interface but for nc to this host
+    ip rule add to 1.1.1.3 dport 1234 table local priority 9
+    
+    # Route packets to the interface but not for nc via the tunnel
+    ip route flush 10
+    ip route add table 10 to 1.1.1.3 via 172.19.152.3 dev nc0
+    ip rule add to 1.1.1.3 table 10 priority 10
+    
+#### Local Portal
+
+    #!/bin/bash
+    set -e
+    
+    # Fix ARP
+    sysctl -w net.ipv4.conf.all.arp_announce=1
+    sysctl -w net.ipv4.conf.all.arp_ignore=1
+    
+    # IPv4 Forwarding
+    sysctl -w net.ipv4.ip_forward=1
+    
+    # Tunnel addr/up
+    ip addr add 172.19.152.3/31 dev nc0
+    ip link set up nc0
+    
+    # Fix routing out of the correct interfaces
+    ip route flush 10
+    ip route add table 10 to 1.1.1.0/24 dev eth1
+    ip rule add from 1.1.1.4 table 10 priority 10
+    
+    ip route flush 11
+    ip route add table 11 to 1.1.1.0/24 dev eth2
+    ip rule add from 1.1.1.5 table 11 priority 11
+    
+    # Route packets from the remote portal's address on the client interface via the tunnel
+    ip route flush 12
+    ip route add table 12 to 1.1.1.0/24 via 172.19.152.2 dev nc0
+    ip rule add from 1.1.1.3 iif eth3 table 12 priority 12
+    
+    # Route packets to the remote portal's address out of the client interface
+    ip route flush 13
+    ip route add table 13 to 1.1.1.3 dev eth3
+    ip rule add to 1.1.1.3 table 13 priority 13
+    
+#### Client
+
+No configuration needed. Simply set the IP to that of the remote server/32 with no gateway.