testing: Add ikev2/per-cpu-sas-encap-transport scenario

Tests transport mode and UDP encapsulation with random source ports.
Interestingly, the responder always uses the same SA to respond (maybe
due to the cache on the policy).

testing/tests/ikev2/per-cpu-sas-encap-transport/pretest.dat

@@ -0,0 +1,14 @@
+sun::iptables-restore < /etc/iptables.rules
+moon::iptables-restore < /etc/iptables.rules
+sun::systemctl start strongswan
+moon::systemctl start strongswan
+sun::expect-connection gw-gw
+moon::expect-connection gw-gw
+# allow UDP encap from any source to 4500
+moon::iptables -A INPUT  -i eth0 -p udp --dport 4500 -j ACCEPT
+moon::iptables -A OUTPUT -o eth0 -p udp --dport 4500 -j ACCEPT
+sun:: iptables -A INPUT  -i eth0 -p udp --dport 4500 -j ACCEPT
+sun:: iptables -A OUTPUT -o eth0 -p udp --dport 4500 -j ACCEPT
+# trigger the creation of the fallback SA, use -I so no UDP socket is used to
+# determine the source address and trigger the acqurie (this packet is lost)
+moon::ping -c 1 -W 1 -I PH_IP_MOON PH_IP_SUN