Add support for kernel 4.15

[petrosagg]

Here is the current error in case it's helpful:

[petrosagg@bach ~]$ cat /var/lib/dkms/jool/3.5.6/build/make.log
DKMS make.log for jool-3.5.6 for kernel 4.15.3-2-ARCH (x86_64)
Fri Feb 23 22:11:34 UTC 2018
make: Entering directory '/usr/lib/modules/4.15.3-2-ARCH/build'
  CC [M]  /var/lib/dkms/jool/3.5.6/build/mod/stateful/pool4/empty.o
  CC [M]  /var/lib/dkms/jool/3.5.6/build/mod/stateful/pool4/db.o
  CC [M]  /var/lib/dkms/jool/3.5.6/build/mod/stateful/pool4/rfc6056.o
  CC [M]  /var/lib/dkms/jool/3.5.6/build/mod/stateful/bib/db.o
  CC [M]  /var/lib/dkms/jool/3.5.6/build/mod/stateful/bib/entry.o
  CC [M]  /var/lib/dkms/jool/3.5.6/build/mod/stateful/bib/pkt_queue.o
  CC [M]  /var/lib/dkms/jool/3.5.6/build/mod/stateful/timer.o
  CC [M]  /var/lib/dkms/jool/3.5.6/build/mod/stateful/fragment_db.o
  CC [M]  /var/lib/dkms/jool/3.5.6/build/mod/stateful/determine_incoming_tuple.o
  CC [M]  /var/lib/dkms/jool/3.5.6/build/mod/stateful/filtering_and_updating.o
/var/lib/dkms/jool/3.5.6/build/mod/stateful/timer.c: In function 'timer_init':
/var/lib/dkms/jool/3.5.6/build/mod/stateful/timer.c:31:2: error: implicit declaration of function 'init_timer'; did you mean 'init_timers'? [-Werror=implicit-function-declaration]
  init_timer(&timer);
  ^~~~~~~~~~
  init_timers
/var/lib/dkms/jool/3.5.6/build/mod/stateful/timer.c:32:17: error: assignment from incompatible pointer type [-Werror=incompatible-pointer-types]
  timer.function = timer_function;
                 ^
/var/lib/dkms/jool/3.5.6/build/mod/stateful/timer.c:34:7: error: 'struct timer_list' has no member named 'data'
  timer.data = 0;
       ^
cc1: some warnings being treated as errors
make[1]: *** [scripts/Makefile.build:316: /var/lib/dkms/jool/3.5.6/build/mod/stateful/timer.o] Error 1
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:1508: _module_/var/lib/dkms/jool/3.5.6/build/mod/stateful] Error 2
make: Leaving directory '/usr/lib/modules/4.15.3-2-ARCH/build'

[ydahhrk]

Here is the current error in case it's helpful:

Thanks :). Wasn't even sure if it crashed or not. I always just upload the issue and worry later.

Is this important for you? Fixing kernel support doesn't usually take long, but since people rarely complains about it, I postpone it until I'm not in the middle of something. But changing my plan is no problem if it benefits someone.

[petrosagg]

No, this is just a test home network. I've downgraded to 4.14 for now :)

[ydahhrk]

Tested in the linux-4.15.3.tar.xz version of the kernel that can be downloaded from kernel.org.