Fix fragmentation test

The assumptions on which this test was based were violated by the
introduction of fast datapath. A new rule is required to block fast
datapath traffic, to ensure that sleeve is selected for forwarding; the
rules must also be moved from the FORWARD chain to INPUT as the router
now runs in the host netns (NB we use INPUT instead of OUTPUT as the
latter results in sleeve receiving an 'operation not permitted' udpv4
write error when it tries to send a packet that is too big, rather than
the packet just being silently dropped as required)

test/105_frag_2_test.sh

@@ -8,7 +8,8 @@ C2=10.2.1.71
 # 700 = Linux's minimum PMTU (552) + weave framing overheads
 # (currently about 60, but we leave some margin). That way the PMTUs
 # seen by containers is still >= 552.
-drop_large_udp_packets="FORWARD -p udp --destination-port 6783 -m length '!' --length 0:700 -j DROP"
+drop_large_sleeve_packets="INPUT -p udp --destination-port 6783 -m length '!' --length 0:700 -j DROP"
+drop_large_fastdp_packets="INPUT -p udp --destination-port 6784 -m length '!' --length 0:700 -j DROP"
 
 start_suite "PMTU discovery and packet fragmentation"
 
@@ -18,7 +19,8 @@ weave_on $HOST2 launch
 start_container $HOST1 $C1/24 --name=c1
 start_container $HOST2 $C2/24 --name=c2
 
-run_on $HOST2 "sudo iptables -I $drop_large_udp_packets"
+run_on $HOST1 "sudo iptables -I $drop_large_sleeve_packets"
+run_on $HOST1 "sudo iptables -I $drop_large_fastdp_packets"
 assert_raises "weave_on $HOST2 connect $HOST1"
 sleep 35 # give weave time to discover the PMTU
 
@@ -28,6 +30,7 @@ sleep 35 # give weave time to discover the PMTU
 exec_on $HOST2 c2 $PING -s 10000 $C1 1>/dev/null 2>&1 || true
 assert_raises "exec_on $HOST2 c2 $PING -s 10000 $C1"
 
-run_on $HOST2 "sudo iptables -D $drop_large_udp_packets"
+run_on $HOST1 "sudo iptables -D $drop_large_fastdp_packets"
+run_on $HOST1 "sudo iptables -D $drop_large_sleeve_packets"
 
 end_suite