ipsec doesn't route TCP with 4.11 kernel

[Don Bowman <db@donbowman.ca>]

I'm not sure how to describe this.

4.11rc2 worked, after that, no.

My ipsec tunnel comes up ok. ICMP works. UDP works. But TCP, the
sender [which is the ipsec client] does not reach the destination.

Its not a routing rule issue (since ICMP/UDP work).
Its not a traffic selector just selecting TCP (I think) since ipsec
status shows just a subnet, no protocol.

Using tcpdump:
# iptables -t mangle -I PREROUTING -m policy --pol ipsec --dir in -j
NFLOG --nflog-group 5
# iptables -t mangle -I POSTROUTING -m policy --pol ipsec --dir out -j
NFLOG --nflog-group 5
# tcpdump -s 0 -n -i nflog:5

I see that it thinks it is sending the TCP packet, but the server end
does not receive.

Does anyone have any suggestion to try?

strongswan is 5.5.1 [on ubuntu 17.04]
kernel is 4.11.0-041100rc8-generic

My rightsubnet is
rightsubnet = 192.168.128.0/17,10.0.0.0/8

so no specific protocol selected, the result is:
CHILD_SA sv{1} established with SPIs c05f1b6c_i 0d58815a_o and TS
192.168.130.4/32 === 10.0.0.0/8 192.168.128.0/17

I tried changing charondebug net=3, but i'm not sure how to interpret
the output:

Apr 25 21:06:34 office charon: 04[NET] received packet: from
64.7.137.180[4500] to 172.16.0.8[4500] (80 bytes)
Apr 25 21:06:34 office charon: 04[ENC] parsed INFORMATIONAL request 4 [ ]
Apr 25 21:06:34 office charon: 04[ENC] generating INFORMATIONAL response 4 [ ]
Apr 25 21:06:34 office charon: 04[NET] sending packet: from
172.16.0.8[4500] to 64.7.137.180[4500] (80 bytes)