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hyperhive/nix/vm-tests/hive-egress-antispoof.nix

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Nix

# `vmTests.<system>.hive-egress-antispoof`: the source check of
# ../host-modules/hive-egress.nix on a real agent bridge, with two nspawn
# containers on it that take their addresses from the hive's dnsmasq
# (../host-modules/hive-gateway/dnsmasq.nix' lease script, the real
# `hive-priv egress-load`, `egress-pin` and `egress-lease`). `hive-squid`
# cannot host this: its stand-in bridge is one NIC, so every agent shares one
# port.
#
# What it pins:
# - the default verdict is `drop`, and each container takes its first lease
# (DHCP from `0.0.0.0`, the reply, the first ARP and IP traffic) with it in
# place; each port is bound to its container's MAC and each lease is in the
# table, without the test adding either;
# - a container sending from its own address reaches the host and the other
# container (the control for every drop below);
# - another container's IPv4 address, another container's MAC, an IPv6 address
# that is not link-local and a DHCP message with another's `chaddr` are
# dropped, and each leaves a `hive-egress-spoof ` line that names the port;
# - a container that keeps talking across renewals of a 2-minute lease is
# never dropped, and its pair is still in `lease_v4` after the first lease
# and its margin would have ended;
# - a DHCP renewal, a link-local IPv6 packet and a restored MAC go through;
# - a pair deleted by hand comes back at the next renewal and rebind; a DHCP
# client message with the port's chaddr passes from any source address, to
# the broadcast or bridge address only; a two-hour wall-clock step keeps
# the pairs dnsmasq prunes; a release removes its pair;
# - a port with no bound MAC sends nothing, and the timer binds it again;
# - `antiSpoof = "log"`, reached by a reload of the unit, brings the bindings
# and the leases with the new table (nothing is dropped in between),
# lets the same spoofs through and logs them.
{ pkgs, hivePriv }:
let
bridge = "hive0";
gateway = "10.42.0.1";
# A DHCP DISCOVER by hand, with the `chaddr` given as the first argument,
# unicast to dnsmasq. A second argument names another destination, a third
# a source address, and a message with a source address leaves from port 68
# like a client's. The container shares the host's store, so it runs from
# there.
bootp = pkgs.writeText "bootp.pl" ''
use IO::Socket::INET;
use Socket;
my $mac = pack("H12", join("", split(/:/, $ARGV[0])));
my ($dest, $src) = ($ARGV[1] || "${gateway}", $ARGV[2]);
my @bind = $src ? (LocalAddr => $src, LocalPort => 68, ReuseAddr => 1) : ();
my $s = IO::Socket::INET->new(Proto => "udp", @bind) or die "socket: $!";
my $head = pack("C4 N n n a4 a4 a4 a4", 1, 1, 6, 0, 4660, 0, 0, "", "", "", "");
my $msg = $head . $mac . ("\0" x 10) . ("\0" x 192) . pack("H8", "63825363") . pack("C4", 53, 1, 1, 255);
$s->send($msg, 0, pack_sockaddr_in(67, inet_aton($dest))) or die "send: $!";
'';
hiveStubs =
{ lib, ... }:
{
options.services.hyperhive = {
deploy.hive-controller.package = lib.mkOption { type = lib.types.package; };
# Off: hive-priv.nix then adds only the link the pin command runs by.
deploy.hive-controller.enable = lib.mkOption {
type = lib.types.bool;
default = false;
};
swarm.forge.domain = lib.mkOption {
type = lib.types.str;
default = "forge.t.local";
};
network = {
enable = lib.mkOption {
type = lib.types.bool;
default = true;
};
bridgeIp = lib.mkOption {
type = lib.types.str;
default = gateway;
};
# Set by hive-egress.nix; nothing here opens it.
exposeHostPorts = lib.mkOption {
type = lib.types.listOf lib.types.port;
default = [ ];
};
bridgeName = lib.mkOption {
type = lib.types.str;
default = bridge;
};
};
};
config.services.hyperhive.deploy.hive-controller.package = hivePriv;
};
# A container that takes its address by DHCP, as the agents do.
container = {
autoStart = true;
privateNetwork = true;
hostBridge = bridge;
config =
{ lib, pkgs, ... }:
{
system.stateVersion = "25.11";
networking.useDHCP = lib.mkForce true;
networking.dhcpcd.extraConfig = "noipv4ll";
networking.dhcpcd.wait = "ipv4";
networking.firewall.allowedUDPPorts = [ 68 ];
environment.systemPackages = [
pkgs.perl
pkgs.socat
];
};
};
in
pkgs.testers.runNixOSTest {
name = "hive-egress-antispoof";
nodes.host =
{ config, lib, ... }:
{
imports = [
hiveStubs
../host-modules/hive-egress.nix
../host-modules/hive-priv.nix
];
virtualisation.memorySize = 2048;
# Explicit: the tests below are about what `drop` does.
services.hyperhive.deploy.hive-controller.egress.antiSpoof = "drop";
networking.bridges.${bridge}.interfaces = [ ];
networking.interfaces.${bridge}.ipv4.addresses = [
{
address = gateway;
prefixLength = 24;
}
];
# The test's own datagram listener, and dnsmasq's DHCP port.
networking.firewall.interfaces.${bridge} = {
allowedUDPPorts = [
67
9999
];
};
services.dnsmasq = {
enable = true;
resolveLocalQueries = false;
settings = {
interface = bridge;
bind-interfaces = true;
port = 0;
# dnsmasq's shortest lease: the test runs through renewals in minutes.
dhcp-range = "10.42.0.2,10.42.0.254,2m";
dhcp-leasefile = "/var/lib/dnsmasq/dnsmasq.leases";
dhcp-script = toString config.services.hyperhive.network.egress.leaseScript;
script-on-renewal = true;
log-dhcp = true;
};
};
systemd.services.dnsmasq = {
wants = [ "network-addresses-${bridge}.service" ];
after = [ "network-addresses-${bridge}.service" ];
};
environment.systemPackages = [ pkgs.socat ];
containers.a = container;
containers.b = container;
specialisation.logmode.configuration = {
services.hyperhive.deploy.hive-controller.egress.antiSpoof = lib.mkForce "log";
};
};
testScript = ''
import re
import shlex
TABLE = "bridge hive_egress"
def ct(name, cmd):
return host.succeed(f"nixos-container run {name} -- sh -c {shlex.quote(cmd)}").strip()
def ct_ok(name, cmd):
return host.execute(f"nixos-container run {name} -- sh -c {shlex.quote(cmd)}")[0] == 0
def mac(name):
return ct(name, "cat /sys/class/net/eth0/address")
def ipv4(name):
out = ct(name, "ip -4 -o addr show dev eth0 scope global")
found = re.search(r"inet (10\.42\.0\.\d+)/", out)
assert found, out
return found.group(1)
def spoof_lines(pattern=""):
out = host.succeed("journalctl -k -o cat --no-pager | grep 'hive-egress-spoof ' || true")
return [line for line in out.splitlines() if re.search(pattern, line)]
def udp_reaches_host(name, src, v6=False):
"""One datagram from the container, sent from `src`. True when the host got it."""
host.succeed("rm -f /tmp/rx")
host.succeed(
"systemd-run --unit=rx --collect "
f"timeout 6 sh -c 'socat -u UDP{6 if v6 else 4}-RECV:9999 - > /tmp/rx'"
)
host.sleep(1)
if v6:
ll = host.succeed("ip -6 -o addr show dev ${bridge} scope link").split()[3].split("/")[0]
target = f"UDP6-SENDTO:[{ll}%eth0]:9999,bind=[{src}]"
else:
target = f"UDP4-SENDTO:${gateway}:9999,bind={src}"
ct_ok(name, f"echo hi | socat -u - {target}")
host.sleep(1)
got = host.succeed("cat /tmp/rx").strip() == "hi"
host.execute("systemctl stop rx.service")
return got
def acks_of_cmd(mac_addr):
return "$(journalctl -u dnsmasq -o cat --no-pager | grep -c 'DHCPACK(${bridge}) .* " + mac_addr + "')"
def acks_of(mac_addr):
return int(host.succeed("echo " + acks_of_cmd(mac_addr)).strip())
def stale_dels():
return host.succeed("journalctl -u dnsmasq -o cat --no-pager | grep -c 'egress-lease: del .* skipped (stale)' || true").strip()
host.start()
host.wait_for_unit("multi-user.target")
host.wait_for_unit("dnsmasq.service")
host.wait_for_unit("hive-egress.service")
# `drop` is set explicitly on the host above, loaded before either container
# exists: the first lease of each container below is taken with it in place.
assert "counter drop" in host.succeed(f"nft list chain {TABLE} spoof"), "antiSpoof = drop is loaded"
for name in ("a", "b"):
host.wait_for_unit(f"container@{name}.service")
host.wait_until_succeeds(
f"nixos-container run {name} -- sh -c 'ip -4 -o addr show dev eth0 | grep -q \"inet 10.42.0.\"'"
)
MAC_A, MAC_B = mac("a"), mac("b")
IP_A, IP_B = ipv4("a"), ipv4("b")
assert MAC_A != MAC_B and IP_A != IP_B
T0 = int(host.succeed("date +%s").strip())
with subtest("each port is bound to its container's MAC and each lease is loaded, with no help from the test"):
host.wait_until_succeeds(f"nft list set {TABLE} port_mac | grep -q '\"vb-a\" . {MAC_A}'")
host.wait_until_succeeds(f"nft list set {TABLE} port_mac | grep -q '\"vb-b\" . {MAC_B}'")
host.wait_until_succeeds(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_A} . {IP_A}'")
host.wait_until_succeeds(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_B} . {IP_B}'")
assert not spoof_lines(), spoof_lines()
with subtest("a container sending from its own address reaches the host and the other container"):
assert ct_ok("a", "ping -c1 -W2 ${gateway}")
assert ct_ok("a", f"ping -c1 -W2 {IP_B}")
assert ct_ok("b", f"ping -c1 -W2 {IP_A}")
assert udp_reaches_host("a", IP_A), "control: a datagram from a's own address arrives"
assert not spoof_lines(), spoof_lines()
with subtest("a container that keeps talking across renewals is never dropped, and its pair outlives the first lease and its margin"):
# The leases run 2 minutes and the pair outlives its lease by 300
# seconds (LEASE_MARGIN_SECS in hive-priv's egress.rs). The pairs were
# loaded before T0, so `T0 + 420` is the latest the first load alone
# would have kept them; the loop runs past it, and only the refresh at
# each renewal keeps them in the set.
def now():
return int(host.succeed("date +%s").strip())
def ack_count(ip):
return host.succeed("journalctl -u dnsmasq -o cat --no-pager").count("DHCPACK(${bridge}) " + ip)
while now() < T0 + 450:
assert ct_ok("a", "ping -c1 -W2 ${gateway}"), "a's traffic is dropped while it renews"
assert ct_ok("b", "ping -c1 -W2 ${gateway}"), "b's traffic is dropped while it renews"
host.sleep(15)
assert not spoof_lines(), spoof_lines()
assert ack_count(IP_A) >= 4 and ack_count(IP_B) >= 4, "each container renewed several times"
host.succeed(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_A} . {IP_A}'")
host.succeed(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_B} . {IP_B}'")
assert udp_reaches_host("a", IP_A), "a's own address still reaches the host after its first lease ended"
with subtest("another container's IPv4 address is dropped, and the line names the port"):
ct("a", f"ip addr add {IP_B}/24 dev eth0")
assert not udp_reaches_host("a", IP_B), "a datagram from b's address must not arrive"
host.wait_until_succeeds("journalctl -k -o cat --no-pager | grep -E 'hive-egress-spoof .*IN=vb-a .*SRC=" + IP_B.replace(".", "\\.") + " '")
assert not spoof_lines(r"IN=vb-b "), "b sent nothing wrong"
ct("a", f"ip addr del {IP_B}/24 dev eth0")
assert udp_reaches_host("a", IP_A), "a's own address still works"
with subtest("an IPv6 address that is not link-local is dropped, a link-local one is not"):
ct("a", "ip -6 addr add fd00::bad/64 dev eth0 nodad")
assert not udp_reaches_host("a", "fd00::bad", v6=True)
host.wait_until_succeeds("journalctl -k -o cat --no-pager | grep -E 'hive-egress-spoof .*IN=vb-a .*SRC=fd00:0*:0*:0*:0*:0*:0*:0*bad '")
ll_a = ct("a", "ip -6 -o addr show dev eth0 scope link").split()[3].split("/")[0]
assert udp_reaches_host("a", ll_a, v6=True), "control: a link-local source goes through"
ct("a", "ip -6 addr del fd00::bad/64 dev eth0")
with subtest("another container's MAC is dropped, and the restored MAC works again"):
ct("a", f"ip link set dev eth0 address {MAC_B}")
assert not ct_ok("a", "ping -c1 -W2 ${gateway}")
host.wait_until_succeeds("journalctl -k -o cat --no-pager | grep -E 'hive-egress-spoof .*IN=vb-a .*MAC=[0-9a-f:]*" + MAC_B + ":'")
ct("a", f"ip link set dev eth0 address {MAC_A}")
assert ct_ok("a", "ping -c1 -W2 ${gateway}"), "the port stays bound to the MAC it had"
assert ct_ok("b", "ping -c1 -W2 ${gateway}"), "b was never affected"
with subtest("another container's MAC and IPv4 address together are dropped, so the leased pair alone is no credential"):
# A static neighbour entry for the host, so the datagram needs no ARP:
# only the check of the port's MAC is left between it and the host.
host_mac = host.succeed("cat /sys/class/net/${bridge}/address").strip()
ct("a", f"ip neigh replace ${gateway} lladdr {host_mac} dev eth0 nud permanent")
ct("a", f"ip link set dev eth0 address {MAC_B}")
ct("a", f"ip addr add {IP_B}/24 dev eth0")
seen = len(spoof_lines(r"IN=vb-a "))
assert not udp_reaches_host("a", IP_B), "b's MAC and address from a's port must not arrive"
assert len(spoof_lines(r"IN=vb-a ")) > seen, "and it is logged against a's port"
ct("a", f"ip addr del {IP_B}/24 dev eth0")
ct("a", f"ip link set dev eth0 address {MAC_A}")
ct("a", "ip neigh del ${gateway} dev eth0")
assert ct_ok("a", "ping -c1 -W2 ${gateway}"), "a works again with its own pair"
with subtest("a DHCP message with another container's chaddr is dropped, one with its own is answered, and a renewal works"):
def discovers(mac_addr):
out = host.succeed("journalctl -u dnsmasq -o cat --no-pager")
return len(re.findall(r"DHCPDISCOVER\(${bridge}\) " + mac_addr, out))
before_b, before_a = discovers(MAC_B), discovers(MAC_A)
ct("a", f"perl ${bootp} {MAC_B}")
ct("a", f"perl ${bootp} {MAC_A}")
host.wait_until_succeeds(f"journalctl -u dnsmasq -o cat --no-pager | grep -c 'DHCPDISCOVER(${bridge}) {MAC_A}' | grep -qv '^{before_a}$'")
assert discovers(MAC_A) == before_a + 1, "the message with a's own chaddr reached dnsmasq"
assert discovers(MAC_B) == before_b, "the message with b's chaddr did not"
host.wait_until_succeeds("journalctl -k -o cat --no-pager | grep -E 'hive-egress-spoof .*IN=vb-a .*DPT=67 '")
acks = host.succeed("journalctl -u dnsmasq -o cat --no-pager").count("DHCPACK(${bridge}) " + IP_A)
ct("a", "dhcpcd --rebind eth0")
host.wait_until_succeeds(
"test $(journalctl -u dnsmasq -o cat --no-pager | grep -c 'DHCPACK(${bridge}) " + IP_A + "') -gt " + str(acks)
)
assert ipv4("a") == IP_A, "the renewal kept the address"
host.wait_until_succeeds(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_A} . {IP_A}'")
assert ct_ok("a", "ping -c1 -W2 ${gateway}")
with subtest("a port with no bound MAC sends nothing, and the timer binds it again"):
host.succeed(f"nft flush set {TABLE} port_mac")
assert not ct_ok("a", "ping -c1 -W2 ${gateway}")
assert not ct_ok("b", "ping -c1 -W2 ${gateway}")
# Nothing starts the pin unit by hand: the timer finds the unbound ports.
host.wait_until_succeeds("nixos-container run a -- ping -c1 -W2 ${gateway}")
host.wait_until_succeeds("nixos-container run b -- ping -c1 -W2 ${gateway}")
with subtest("a pair that left the set comes back at the container's next renewal and its next rebind, and nothing is dropped"):
# The renewal is a unicast REQUEST from the leased address, the rebind a
# broadcast one from it. Neither can match the pair: it is gone.
for verb in ("renew", "rebind"):
host.succeed(f"nft delete element {TABLE} lease_v4 {{ {MAC_A} . {IP_A} }}")
host.fail(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_A} . {IP_A}'")
assert not ct_ok("a", "ping -c1 -W2 ${gateway}"), "control: a is cut off without its pair"
assert ct_ok("b", "ping -c1 -W2 ${gateway}"), "control: b is not"
drops_before = len(spoof_lines(r"IN=vb-a .*DPT=67 "))
acks = ack_count(IP_A)
ct("a", f"dhcpcd --{verb} eth0")
host.wait_until_succeeds(f"test $(journalctl -u dnsmasq -o cat --no-pager | grep -c 'DHCPACK(${bridge}) {IP_A}') -gt {acks}", timeout=30)
host.wait_until_succeeds(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_A} . {IP_A}'", timeout=30)
assert ct_ok("a", "ping -c1 -W2 ${gateway}"), f"a reaches the host again after its {verb}"
assert len(spoof_lines(r"IN=vb-a .*DPT=67 ")) == drops_before, f"the {verb} was not dropped"
with subtest("a DHCP client message with the port's own chaddr passes from any source address to the broadcast or bridge address only"):
host_mac = host.succeed("cat /sys/class/net/${bridge}/address").strip()
ct("a", f"ip neigh replace ${gateway} lladdr {host_mac} dev eth0 nud permanent")
ct("a", f"ip neigh replace {IP_B} lladdr {MAC_B} dev eth0 nud permanent")
ct("a", f"ip addr add {IP_B}/24 dev eth0")
discovers_a = host.succeed("journalctl -u dnsmasq -o cat --no-pager").count("DHCPDISCOVER(${bridge}) " + MAC_A)
ct("a", f"perl ${bootp} {MAC_A} ${gateway} {IP_B}")
host.wait_until_succeeds(
"test $(journalctl -u dnsmasq -o cat --no-pager | grep -c 'DHCPDISCOVER(${bridge}) " + MAC_A + "') -gt " + str(discovers_a),
timeout=30,
)
seen = len(spoof_lines(r"IN=vb-a .*DST=" + IP_B.replace(".", r"\.") + " .*DPT=67 "))
ct("a", f"perl ${bootp} {MAC_A} {IP_B} {IP_B}")
host.wait_until_succeeds("journalctl -k -o cat --no-pager | grep -E 'hive-egress-spoof .*IN=vb-a .*DST=" + IP_B.replace(".", "\\.") + " .*DPT=67 '", timeout=30)
assert len(spoof_lines(r"IN=vb-a .*DST=" + IP_B.replace(".", r"\.") + " .*DPT=67 ")) > seen, "to another container's address it is dropped"
ct("a", f"ip addr del {IP_B}/24 dev eth0")
ct("a", f"ip neigh del {IP_B} dev eth0")
ct("a", "ip neigh del ${gateway} dev eth0")
with subtest("a step of the wall clock that makes dnsmasq prune every lease leaves the pairs in the set and the containers reaching the host"):
# The qemu guest has no suspend. A step of the wall clock is the same
# divergence: dnsmasq counts wall time and expires every lease, while
# the nft timeouts and the containers' leases count monotonic time.
assert ct_ok("a", "ping -c1 -W2 ${gateway}") and ct_ok("b", "ping -c1 -W2 ${gateway}")
drops_before = len(spoof_lines(r"IN=vb-[ab] "))
skipped = int(stale_dels())
host.succeed("date -s @$(( $(date +%s) + 7200 ))")
# Any DHCP packet makes dnsmasq prune: a DISCOVER with a's own chaddr.
ct("a", "perl ${bootp} " + MAC_A)
host.wait_until_succeeds("test $(journalctl -u dnsmasq -o cat --no-pager | grep -c 'egress-lease: del .* skipped (stale)') -ge " + str(skipped + 2), timeout=60)
host.succeed(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_A} . {IP_A}'")
host.succeed(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_B} . {IP_B}'")
assert ct_ok("a", "ping -c1 -W2 ${gateway}"), "a reaches the host after dnsmasq forgot its lease"
assert ct_ok("b", "ping -c1 -W2 ${gateway}"), "b reaches the host after dnsmasq forgot its lease"
assert not host.succeed("journalctl -u dnsmasq -o cat --no-pager | grep 'egress-lease: del .* applied' || true").strip(), "no delete was applied"
# Each container then renews against a dnsmasq that has forgotten its
# lease, and ends with a lease again. It keeps reaching the host.
acks_a, acks_b = acks_of(MAC_A), acks_of(MAC_B)
for name in ("a", "b"):
ct(name, "dhcpcd --renew eth0")
host.wait_until_succeeds(f"test {acks_of_cmd(MAC_A)} -gt {acks_a} && test {acks_of_cmd(MAC_B)} -gt {acks_b}", timeout=90)
IP_A, IP_B = ipv4("a"), ipv4("b")
host.wait_until_succeeds(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_A} . {IP_A}'", timeout=60)
host.wait_until_succeeds(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_B} . {IP_B}'", timeout=60)
assert len(spoof_lines(r"IN=vb-[ab] ")) == drops_before, "nothing of a or b was dropped"
with subtest("a release still removes the pair at once"):
# A fresh lease first: the release must name an expiry in the future.
acks = ack_count(IP_A)
ct("a", "dhcpcd --rebind eth0")
host.wait_until_succeeds(f"test $(journalctl -u dnsmasq -o cat --no-pager | grep -c 'DHCPACK(${bridge}) {IP_A}') -gt {acks}", timeout=30)
host.succeed(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_A} . {IP_A}'")
ct("a", "dhcpcd -k eth0")
host.wait_until_fails(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_A} . {IP_A}'", timeout=30)
host.succeed(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_B} . {IP_B}'")
host.wait_until_succeeds("journalctl -u dnsmasq -o cat --no-pager | grep -E 'egress-lease: del mac=" + MAC_A + " .* applied'", timeout=30)
# a asks again, as its container would after a restart.
ct("a", "systemctl restart dhcpcd")
host.wait_until_succeeds("nixos-container run a -- ping -c1 -W2 ${gateway}", timeout=60)
IP_A = ipv4("a")
host.wait_until_succeeds(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_A} . {IP_A}'", timeout=30)
with subtest("antiSpoof = log keeps the bindings and the leases, lets a spoofed datagram through and logs it"):
host.succeed("/run/current-system/specialisation/logmode/bin/switch-to-configuration test")
assert "counter accept" in host.succeed(f"nft list chain {TABLE} spoof"), "the table was reloaded in log mode"
# No waiting: the reload put the sets in with the table.
host.succeed(f"nft list set {TABLE} port_mac | grep -q '\"vb-a\" . {MAC_A}'")
host.succeed(f"nft list set {TABLE} lease_v4 | grep -q '{MAC_B} . {IP_B}'")
assert ct_ok("a", "ping -c1 -W2 ${gateway}"), "control: own address, right after the reload"
seen = len(spoof_lines())
ct("a", f"ip addr add {IP_B}/24 dev eth0")
assert udp_reaches_host("a", IP_B), "log mode lets the spoofed datagram through"
host.wait_until_succeeds("journalctl -k -o cat --no-pager | grep 'hive-egress-spoof ' | wc -l | grep -qv '^" + str(seen) + "$'")
assert spoof_lines(r"IN=vb-a .*SRC=" + IP_B.replace(".", r"\.") + " ")
'';
}