[strongSwan] IPsec in unstable network

[Zesen Qian]

Hello list,
I 'm using strongswan in an unstable network, by 'unstable' I mean there
may be 5 minutes out of an hour, that I cannot connect to the server.
Most of the time I can establish the connection smoothly, but after
several hours or several days, I lost the connection to server. 

charon.log: https://bpaste.net/show/63b9d0e1dfc6
ipsec.statusall: https://bpaste.net/show/ec586241759a

At this point I cannot ping hosts on the other side of tunnel, however
if I do a ipsec stop && ipsec start, the tunnel is up and everything
works again.

Any comment is appreciated.

-- 
Zesen Qian (钱泽森)