[client] Fix 'Could not set destination IP.' in hostname resolution in '-P icmp' mode

[mrash]

It seems that hostname resolution is not working when SPA packets are spoofed. Here is the command line to trigger the problem:

fwknop -A tcp/22 -a 127.0.0.2 -D --verbose --verbose -P icmp --icmp-type 8 --icmp-code 0 -Q 1.2.3.4

[fjoncourt]

Hi Michael,

Same problem when the spoof string is an hostname. But reading the man page, it only waits for an ipv4 string.
I am going to fix the above issue.

[mrash]

Excellent, I've assigned this to the fwknop-2.5 release milestone.

[fjoncourt]

Done (check last commit). I have added a test for this. I have not touched the spoof string. If it makes sense to set a hostname instead of an ip address, then it should also be resolved.
I think I will add a constant somewhere to specify AF_INET as the default protocol for resolving hostname. If the default behavior comes to change to AF_INET6 it will be easy to update.

[mrash]

Merged, thanks!