Kernel module compilation error on 4.19

[dongjuanyong]

CC [M] /home/build/openwrt/lede/build_dir/target-x86_64_musl/wifidog-ng-/main.o
/home/build/openwrt/lede/build_dir/target-x86_64_musl/wifidog-ng-/main.c: In function 'wd_nf_nat_setup_info':
/home/build/openwrt/lede/build_dir/target-x86_64_musl/wifidog-ng-/main.c:41:34: error: passing argument 2 of 'nf_nat_setup_info' from incompatible pointer type [-Werror=incompatible-pointer-types]
return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
^
In file included from /home/build/openwrt/lede/build_dir/target-x86_64_musl/wifidog-ng-/main.c:16:0:
./include/net/netfilter/nf_nat.h:41:14: note: expected 'const struct nf_nat_range2 *' but argument is of type 'struct nf_nat_range *'
unsigned int nf_nat_setup_info(struct nf_conn *ct,
^~~~~~~~~~~~~~~~~
/home/build/openwrt/lede/build_dir/target-x86_64_musl/wifidog-ng-/main.c: In function 'wifidog_hook':
/home/build/openwrt/lede/build_dir/target-x86_64_musl/wifidog-ng-/main.c:120:12: error: implicit declaration of function 'nf_nat_ipv4_in'; did you mean 'nf_nat_setup_info'? [-Werror=implicit-function-declaration]
return nf_nat_ipv4_in(priv, skb, state, wd_nf_nat_setup_info);
^~~~~~~~~~~~~~
nf_nat_setup_info
cc1: some warnings being treated as errors

"nf_nat_range" has been changed to "nf_nat_range2" since kernel 4.18, as well as "nf_nat_ipv4_in".

[zhaojh329]

Can you make a PR?

[dongjuanyong]

Sorry, I didn't look into the linux kernel so much and could not make it.
Since a lot of codes changed (this commit), I think it maybe need some hardwork.
Thanks for your great work and good luck.