convert pppoe test to a derivation

* move shell script to a runCommand
* multicast needs special options to run on loopback
 (nix-build sandbox disables non-local network interfaces)

ci.nix

@@ -1,4 +1,5 @@
 {
   smoke = import ./tests/smoke/test.nix;
   pseudofiles = import ./tests/pseudofiles/test.nix;
+  pppoe = import ./tests/pppoe/test.nix;
 }

scripts/run-qemu.sh

@@ -18,8 +18,8 @@ qemu-system-mips \
     -echr 16 \
     -append "default console=ttyS0,38400n8 panic=10 oops=panic init=$INIT loglevel=8 root=/dev/vda" \
     -drive file=$2,format=raw,readonly=on,if=virtio \
-    -netdev socket,id=access,mcast=230.0.0.1:1234 \
+    -netdev socket,id=access,mcast=230.0.0.1:1234,localaddr=127.0.0.1 \
     -device virtio-net-pci,disable-legacy=on,disable-modern=off,netdev=access,mac=ba:ad:1d:ea:21:02 \
-    -netdev socket,id=lan,mcast=230.0.0.1:1235 \
+    -netdev socket,id=lan,mcast=230.0.0.1:1235,localaddr=127.0.0.1 \
     -device virtio-net-pci,disable-legacy=on,disable-modern=off,netdev=lan,mac=ba:ad:1d:ea:21:01 \
     -kernel $1 -display none $flags     ${QEMU_OPTIONS}

tests/pppoe/run.sh

@@ -1,31 +0,0 @@
-#!/usr/bin/env sh
-
-cleanup(){
-    if test -e foo.pid && test -d /proc/`cat foo.pid` ; then
-	echo "killing qemu"
-	kill `cat foo.pid`
-    fi
-}
-trap cleanup EXIT
-fatal(){
-    err=$?
-    echo "FAIL: command $(eval echo $BASH_COMMAND) exited with code $err"
-    exit $err
-}
-trap fatal ERR
-
-NIXPKGS_ALLOW_UNSUPPORTED_SYSTEM=1 nix-build '<liminix>' -I liminix-config=./configuration.nix --arg device "import <liminix/devices/qemu>" -A outputs.default $*
-
-if ! ( echo "cont" | socat - unix-connect:../support/ppp-server/qemu-monitor); then
-    echo "need pppoe server running"
-    exit 1
-fi
-
-../../scripts/run-qemu.sh --background foo.sock result/vmlinux result/squashfs
-nix-shell -p expect --run "expect getaddress.expect"
-
-set -o pipefail
-response=$(nix-shell -p python3Packages.scapy --run 'python ./test-dhcp-service.py' )
-
-echo "$response"
-echo "$response" | nix-shell -p jq --run "jq -e 'select((.router ==  \"192.168.19.1\") and (.server_id==\"192.168.19.1\"))'"

tests/pppoe/test-dhcp-service.py

@@ -66,10 +66,9 @@ sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
 sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, MULTICAST_TTL)
 
 sock.bind((MCAST_GRP, MCAST_PORT))
-host = socket.gethostbyname(socket.gethostname())
+sock.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_IF, socket.inet_aton('127.0.0.1'))
-sock.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_IF, socket.inet_aton(host))
 sock.setsockopt(socket.SOL_IP, socket.IP_ADD_MEMBERSHIP,
-                socket.inet_aton(MCAST_GRP) + socket.inet_aton(host))
+                socket.inet_aton(MCAST_GRP) + socket.inet_aton('127.0.0.1'))
 
 endtime = time.time() + TIMEOUT
 sock.sendto(payload, (MCAST_GRP, MCAST_PORT))
@@ -77,8 +76,8 @@ sock.sendto(payload, (MCAST_GRP, MCAST_PORT))
 while time.time() < endtime:
   try:
     data, addr = sock.recvfrom(1024)
-  except socket.error:
+  except socket.error as e:
-    print('Exception')
+    print('recv exception: ', e)
   else:
     reply = Ether(data)
     if is_dhcp_offer(reply):

tests/pppoe/test.nix

@@ -0,0 +1,61 @@
+{
+  liminix
+, nixpkgs
+}:
+let img = (import liminix {
+      device = import "${liminix}/devices/qemu/";
+      liminix-config = ./configuration.nix;
+    }).outputs.default;
+    pkgs = import <nixpkgs> {};
+    ros = pkgs.callPackage ../support/ppp-server {};
+    run-qemu = pkgs.writeShellScriptBin "run-qemu" ''
+      export PATH="${pkgs.lib.makeBinPath [pkgs.qemu]}:$PATH"
+      ${builtins.readFile ../../scripts/run-qemu.sh}
+    '';
+
+in pkgs.runCommand "check" {
+  nativeBuildInputs = with pkgs; [
+    python3Packages.scapy
+    expect
+    jq
+    socat
+    ros.routeros
+    run-qemu
+  ] ;
+} ''
+serverstatedir=$(mktemp -d -t routeros-XXXXXX)
+# python scapy drags in matplotlib which doesn't enjoy running in
+# a sandbox with no $HOME, hence this environment variable
+export MPLCONFIGDIR=$(mktemp -d -t routeros-XXXXXX)
+
+killpid(){
+  if test -e $1 && test -d /proc/`cat $1` ; then
+    pid=$(cat $1)
+    kill $pid
+  fi
+}
+
+cleanup(){
+  killpid $serverstatedir/pid
+  test -n "$MPLCONFIGDIR" && test -d "$MPLCONFIGDIR" && rm -rf "$MPLCONFIGDIR"
+  killpid foo.pid
+}
+trap cleanup EXIT
+
+fatal(){
+  err=$?
+  echo "FAIL: command $(eval echo $BASH_COMMAND) exited with code $err"
+  exit $err
+}
+trap fatal ERR
+
+routeros $serverstatedir
+
+run-qemu --background foo.sock ${img}/vmlinux ${img}/squashfs
+expect ${./getaddress.expect}
+
+set -o pipefail
+response=$(python ${./test-dhcp-service.py})
+echo "$response" | jq -e 'select((.router ==  "192.168.19.1") and (.server_id=="192.168.19.1"))'
+echo $response > $out
+''