[strongSwan] Interface address change not acted upon

[Martin Willi]

> whenever there is no usable address on eth0, charon dies again.
> Is this intended?

Of course not. If charon does not have a valid route, it should defer
any MOBIKE update:

> 192.168.0.1 disappeared from eth0
> no route found to reach 192.168.0.2, MOBIKE update deferred

If a usable address and a valid route appears, it should update the
tunnel using MOBIKE:

> 192.168.0.3 appeared on eth0
> requesting address change using MOBIKE
> generating INFORMATIONAL request 8 [ N(ADD_4_ADDR) N(ADD_4_ADDR) ]
> sending packet: from 192.168.0.3[4500] to 192.168.0.2[4500]

Please try to attach a debugger (ipsec start --attach-gdb), a backtrace
of the crash would help.

Regards
Martin