script and README to start routeros configured for pppoe

tests/support/ppp-server/README.md

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+# ppp-server
+
+To test a router, we need an upstream connection. In this directory,
+find
+
+* run.sh, a script that will start a RouterOS image in qemu.
+  Login when prompted, username is "admin", blank password
+* routeros.config, a set of commands you can feed into routeros
+  to set up PPPoE
+
+To get the chr-7.5.img image, visit https://mikrotik.com/download and
+look in the section titled "Cloud Hosted Router" for "Raw disk image"
+
+You may need to open your firewall a bit to allow multicast packets
+so that the upstream and the liminix qemu instances may communicate
+
+config.networking.firewall.extraCommands = ''
+ip46tables -A nixos-fw -m pkttype --pkt-type multicast -p udp --dport 1234:1236 -j nixos-fw-accept
+'';
+
+## To connect to the routeros serial
+
+The Qemu instance running RouterOS is headless, but it creates
+two unix sockets for serial port and monitor.
+
+    socat -,raw,echo=0,icanon=0,isig=0,icrnl=0,escape=0x0f    tests/support/ppp-server/qemu-console
+
+    socat -,raw,echo=0,icanon=0,isig=0,icrnl=0,escape=0x0f    tests/support/ppp-server/qemu-monitor

tests/support/ppp-server/chr.sh

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+#!/usr/bin/env sh
+/nix/store/ydwiiagdhczynh2lbqh418rglibv93rv-qemu-host-cpu-only-7.0.0/bin/qemu-kvm \
+    -M q35  -display none \
+    -m 1024 \
+    -accel kvm \
+    -daemonize \
+    -serial unix:qemu-console,server,nowait  -monitor unix:qemu-monitor,server,nowait \
+    -drive file=chr-7.5.img,format=raw,if=virtio \
+    -netdev socket,id=access,mcast=230.0.0.1:1234 \
+    -device virtio-net-pci,disable-legacy=on,disable-modern=off,netdev=access,mac=ba:ad:1d:ea:11:02 \
+    -netdev socket,id=world,mcast=230.0.0.1:1236 \
+    -device virtio-net-pci,disable-legacy=on,disable-modern=off,netdev=world,mac=ba:ad:1d:ea:11:01

tests/support/ppp-server/routeros.config

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+# sep/23/2022 21:05:02 by RouterOS 7.5
+# software id =
+#
+# run "/export show-sensitive" to recreate this
+#
+/interface ethernet
+set [ find default-name=ether1 ] disable-running-check=no name=access
+set [ find default-name=ether2 ] disable-running-check=no name=world
+/disk
+set sata1 disabled=no
+/interface wireless security-profiles
+set [ find default=yes ] supplicant-identity=MikroTik
+/ip pool
+add name=pppoe-pool ranges=192.168.100.10-192.168.100.99
+/port
+set 0 name=serial0
+/ppp profile
+add local-address=192.168.100.1 name=pppoe-profile remote-address=pppoe-pool
+/interface pppoe-server server
+add default-profile=pppoe-profile disabled=no interface=access service-name=internet
+/ip dhcp-client
+add interface=*1
+/ppp secret
+add name=db123@a.1 password=NotReallyTheSecret profile=pppoe-profile service=pppoe