selftests: netfilter: add selftest for directional zone support

Add a script to exercise NAT port clash resolution with directional zones.

Add net namespaces that use the same IP address and connect them to a
gateway.

Gateway uses policy routing based on iif/mark and conntrack zones to
isolate the client namespaces.  In server direction, same zone with NAT
to single address is used.

Then, connect to a server from each client netns, using identical
connection id, i.e.  saddr:sport -> daddr:dport.

Expectation is for all connections to succeeed: NAT gatway is
supposed to do port reallocation for each of the (clashing) connections.

This is based on the description/use case provided in the commit message of
beb5cbd91fb55d ("netfilter: nf_conntrack: add direction support for zones").

Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/tools/testing/selftests/netfilter/nft_nat_zones.sh b/tools/testing/selftests/netfilter/nft_nat_zones.sh
new file mode 100755 (executable)
index 0000000..b9ab373
--- /dev/null
+++ b/tools/testing/selftests/netfilter/nft_nat_zones.sh
@@ -0,0 +1,309 @@
+#!/bin/bash
+#
+# Test connection tracking zone and NAT source port reallocation support.
+#
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
+# Don't increase too much, 2000 clients should work
+# just fine but script can then take several minutes with
+# KASAN/debug builds.
+maxclients=100
+
+have_iperf=1
+ret=0
+
+# client1---.
+#            veth1-.
+#                  |
+#               NAT Gateway --veth0--> Server
+#                  | |
+#            veth2-' |
+# client2---'        |
+#  ....              |
+# clientX----vethX---'
+
+# All clients share identical IP address.
+# NAT Gateway uses policy routing and conntrack zones to isolate client
+# namespaces.  Each client connects to Server, each with colliding tuples:
+#   clientsaddr:10000 -> serveraddr:dport
+#   NAT Gateway is supposed to do port reallocation for each of the
+#   connections.
+
+sfx=$(mktemp -u "XXXXXXXX")
+gw="ns-gw-$sfx"
+cl1="ns-cl1-$sfx"
+cl2="ns-cl2-$sfx"
+srv="ns-srv-$sfx"
+
+v4gc1=$(sysctl -n net.ipv4.neigh.default.gc_thresh1 2>/dev/null)
+v4gc2=$(sysctl -n net.ipv4.neigh.default.gc_thresh2 2>/dev/null)
+v4gc3=$(sysctl -n net.ipv4.neigh.default.gc_thresh3 2>/dev/null)
+v6gc1=$(sysctl -n net.ipv6.neigh.default.gc_thresh1 2>/dev/null)
+v6gc2=$(sysctl -n net.ipv6.neigh.default.gc_thresh2 2>/dev/null)
+v6gc3=$(sysctl -n net.ipv6.neigh.default.gc_thresh3 2>/dev/null)
+
+cleanup()
+{
+       ip netns del $gw
+       ip netns del $srv
+       for i in $(seq 1 $maxclients); do
+               ip netns del ns-cl$i-$sfx 2>/dev/null
+       done
+
+       sysctl -q net.ipv4.neigh.default.gc_thresh1=$v4gc1 2>/dev/null
+       sysctl -q net.ipv4.neigh.default.gc_thresh2=$v4gc2 2>/dev/null
+       sysctl -q net.ipv4.neigh.default.gc_thresh3=$v4gc3 2>/dev/null
+       sysctl -q net.ipv6.neigh.default.gc_thresh1=$v6gc1 2>/dev/null
+       sysctl -q net.ipv6.neigh.default.gc_thresh2=$v6gc2 2>/dev/null
+       sysctl -q net.ipv6.neigh.default.gc_thresh3=$v6gc3 2>/dev/null
+}
+
+nft --version > /dev/null 2>&1
+if [ $? -ne 0 ];then
+       echo "SKIP: Could not run test without nft tool"
+       exit $ksft_skip
+fi
+
+ip -Version > /dev/null 2>&1
+if [ $? -ne 0 ];then
+       echo "SKIP: Could not run test without ip tool"
+       exit $ksft_skip
+fi
+
+conntrack -V > /dev/null 2>&1
+if [ $? -ne 0 ];then
+       echo "SKIP: Could not run test without conntrack tool"
+       exit $ksft_skip
+fi
+
+iperf3 -v >/dev/null 2>&1
+if [ $? -ne 0 ];then
+       have_iperf=0
+fi
+
+ip netns add "$gw"
+if [ $? -ne 0 ];then
+       echo "SKIP: Could not create net namespace $gw"
+       exit $ksft_skip
+fi
+ip -net "$gw" link set lo up
+
+trap cleanup EXIT
+
+ip netns add "$srv"
+if [ $? -ne 0 ];then
+       echo "SKIP: Could not create server netns $srv"
+       exit $ksft_skip
+fi
+
+ip link add veth0 netns "$gw" type veth peer name eth0 netns "$srv"
+ip -net "$gw" link set veth0 up
+ip -net "$srv" link set lo up
+ip -net "$srv" link set eth0 up
+
+sysctl -q net.ipv6.neigh.default.gc_thresh1=512  2>/dev/null
+sysctl -q net.ipv6.neigh.default.gc_thresh2=1024 2>/dev/null
+sysctl -q net.ipv6.neigh.default.gc_thresh3=4096 2>/dev/null
+sysctl -q net.ipv4.neigh.default.gc_thresh1=512  2>/dev/null
+sysctl -q net.ipv4.neigh.default.gc_thresh2=1024 2>/dev/null
+sysctl -q net.ipv4.neigh.default.gc_thresh3=4096 2>/dev/null
+
+for i in $(seq 1 $maxclients);do
+  cl="ns-cl$i-$sfx"
+
+  ip netns add "$cl"
+  if [ $? -ne 0 ];then
+     echo "SKIP: Could not create client netns $cl"
+     exit $ksft_skip
+  fi
+  ip link add veth$i netns "$gw" type veth peer name eth0 netns "$cl" > /dev/null 2>&1
+  if [ $? -ne 0 ];then
+    echo "SKIP: No virtual ethernet pair device support in kernel"
+    exit $ksft_skip
+  fi
+done
+
+for i in $(seq 1 $maxclients);do
+  cl="ns-cl$i-$sfx"
+  echo netns exec "$cl" ip link set lo up
+  echo netns exec "$cl" ip link set eth0 up
+  echo netns exec "$cl" sysctl -q net.ipv4.tcp_syn_retries=2
+  echo netns exec "$gw" ip link set veth$i up
+  echo netns exec "$gw" sysctl -q net.ipv4.conf.veth$i.arp_ignore=2
+  echo netns exec "$gw" sysctl -q net.ipv4.conf.veth$i.rp_filter=0
+
+  # clients have same IP addresses.
+  echo netns exec "$cl" ip addr add 10.1.0.3/24 dev eth0
+  echo netns exec "$cl" ip addr add dead:1::3/64 dev eth0
+  echo netns exec "$cl" ip route add default via 10.1.0.2 dev eth0
+  echo netns exec "$cl" ip route add default via dead:1::2 dev eth0
+
+  # NB: same addresses on client-facing interfaces.
+  echo netns exec "$gw" ip addr add 10.1.0.2/24 dev veth$i
+  echo netns exec "$gw" ip addr add dead:1::2/64 dev veth$i
+
+  # gw: policy routing
+  echo netns exec "$gw" ip route add 10.1.0.0/24 dev veth$i table $((1000+i))
+  echo netns exec "$gw" ip route add dead:1::0/64 dev veth$i table $((1000+i))
+  echo netns exec "$gw" ip route add 10.3.0.0/24 dev veth0 table $((1000+i))
+  echo netns exec "$gw" ip route add dead:3::0/64 dev veth0 table $((1000+i))
+  echo netns exec "$gw" ip rule add fwmark $i lookup $((1000+i))
+done | ip -batch /dev/stdin
+
+ip -net "$gw" addr add 10.3.0.1/24 dev veth0
+ip -net "$gw" addr add dead:3::1/64 dev veth0
+
+ip -net "$srv" addr add 10.3.0.99/24 dev eth0
+ip -net "$srv" addr add dead:3::99/64 dev eth0
+
+ip netns exec $gw nft -f /dev/stdin<<EOF
+table inet raw {
+       map iiftomark {
+               type ifname : mark
+       }
+
+       map iiftozone {
+               typeof iifname : ct zone
+       }
+
+       set inicmp {
+               flags dynamic
+               type ipv4_addr . ifname . ipv4_addr
+       }
+       set inflows {
+               flags dynamic
+               type ipv4_addr . inet_service . ifname . ipv4_addr . inet_service
+       }
+
+       set inflows6 {
+               flags dynamic
+               type ipv6_addr . inet_service . ifname . ipv6_addr . inet_service
+       }
+
+       chain prerouting {
+               type filter hook prerouting priority -64000; policy accept;
+               ct original zone set meta iifname map @iiftozone
+               meta mark set meta iifname map @iiftomark
+
+               tcp flags & (syn|ack) == ack add @inflows { ip saddr . tcp sport . meta iifname . ip daddr . tcp dport counter }
+               add @inflows6 { ip6 saddr . tcp sport . meta iifname . ip6 daddr . tcp dport counter }
+               ip protocol icmp add @inicmp { ip saddr . meta iifname . ip daddr counter }
+       }
+
+       chain nat_postrouting {
+               type nat hook postrouting priority 0; policy accept;
+                ct mark set meta mark meta oifname veth0 masquerade
+       }
+
+       chain mangle_prerouting {
+               type filter hook prerouting priority -100; policy accept;
+               ct direction reply meta mark set ct mark
+       }
+}
+EOF
+
+( echo add element inet raw iiftomark \{
+       for i in $(seq 1 $((maxclients-1))); do
+               echo \"veth$i\" : $i,
+       done
+       echo \"veth$maxclients\" : $maxclients \}
+       echo add element inet raw iiftozone \{
+       for i in $(seq 1 $((maxclients-1))); do
+               echo \"veth$i\" : $i,
+       done
+       echo \"veth$maxclients\" : $maxclients \}
+) | ip netns exec $gw nft -f /dev/stdin
+
+ip netns exec "$gw" sysctl -q net.ipv4.conf.all.forwarding=1 > /dev/null
+ip netns exec "$gw" sysctl -q net.ipv6.conf.all.forwarding=1 > /dev/null
+ip netns exec "$gw" sysctl -q net.ipv4.conf.all.rp_filter=0 >/dev/null
+
+# useful for debugging: allows to use 'ping' from clients to gateway.
+ip netns exec "$gw" sysctl -q net.ipv4.fwmark_reflect=1 > /dev/null
+ip netns exec "$gw" sysctl -q net.ipv6.fwmark_reflect=1 > /dev/null
+
+for i in $(seq 1 $maxclients); do
+  cl="ns-cl$i-$sfx"
+  ip netns exec $cl ping -i 0.5 -q -c 3 10.3.0.99 > /dev/null 2>&1 &
+  if [ $? -ne 0 ]; then
+     echo FAIL: Ping failure from $cl 1>&2
+     ret=1
+     break
+  fi
+done
+
+wait
+
+for i in $(seq 1 $maxclients); do
+   ip netns exec $gw nft get element inet raw inicmp "{ 10.1.0.3 . \"veth$i\" . 10.3.0.99 }" | grep -q "{ 10.1.0.3 . \"veth$i\" . 10.3.0.99 counter packets 3 bytes 252 }"
+   if [ $? -ne 0 ];then
+      ret=1
+      echo "FAIL: counter icmp mismatch for veth$i" 1>&2
+      ip netns exec $gw nft get element inet raw inicmp "{ 10.1.0.3 . \"veth$i\" . 10.3.0.99 }" 1>&2
+      break
+   fi
+done
+
+ip netns exec $gw nft get element inet raw inicmp "{ 10.3.0.99 . \"veth0\" . 10.3.0.1 }" | grep -q "{ 10.3.0.99 . \"veth0\" . 10.3.0.1 counter packets $((3 * $maxclients)) bytes $((252 * $maxclients)) }"
+if [ $? -ne 0 ];then
+    ret=1
+    echo "FAIL: counter icmp mismatch for veth0: { 10.3.0.99 . \"veth0\" . 10.3.0.1 counter packets $((3 * $maxclients)) bytes $((252 * $maxclients)) }"
+    ip netns exec $gw nft get element inet raw inicmp "{ 10.3.99 . \"veth0\" . 10.3.0.1 }" 1>&2
+fi
+
+if  [ $ret -eq 0 ]; then
+       echo "PASS: ping test from all $maxclients namespaces"
+fi
+
+if [ $have_iperf -eq 0 ];then
+       echo "SKIP: iperf3 not installed"
+       if [ $ret -ne 0 ];then
+           exit $ret
+       fi
+       exit $ksft_skip
+fi
+
+ip netns exec $srv iperf3 -s > /dev/null 2>&1 &
+iperfpid=$!
+sleep 1
+
+for i in $(seq 1 $maxclients); do
+  if [ $ret -ne 0 ]; then
+     break
+  fi
+  cl="ns-cl$i-$sfx"
+  ip netns exec $cl iperf3 -c 10.3.0.99 --cport 10000 -n 1 > /dev/null
+  if [ $? -ne 0 ]; then
+     echo FAIL: Failure to connect for $cl 1>&2
+     ip netns exec $gw conntrack -S 1>&2
+     ret=1
+  fi
+done
+if [ $ret -eq 0 ];then
+       echo "PASS: iperf3 connections for all $maxclients net namespaces"
+fi
+
+kill $iperfpid
+wait
+
+for i in $(seq 1 $maxclients); do
+   ip netns exec $gw nft get element inet raw inflows "{ 10.1.0.3 . 10000 . \"veth$i\" . 10.3.0.99 . 5201 }" > /dev/null
+   if [ $? -ne 0 ];then
+      ret=1
+      echo "FAIL: can't find expected tcp entry for veth$i" 1>&2
+      break
+   fi
+done
+if [ $ret -eq 0 ];then
+       echo "PASS: Found client connection for all $maxclients net namespaces"
+fi
+
+ip netns exec $gw nft get element inet raw inflows "{ 10.3.0.99 . 5201 . \"veth0\" . 10.3.0.1 . 10000 }" > /dev/null
+if [ $? -ne 0 ];then
+    ret=1
+    echo "FAIL: cannot find return entry on veth0" 1>&2
+fi
+
+exit $ret