Hi Alyssa,
On Fri, Dec 20, 2024 at 12:10:02AM +0100, Alyssa Ross wrote:
> Since iptables commit 810f8568 (libxtables: xtoptions: Implement
> XTTYPE_ETHERMACMASK), nftables failed to build for musl libc:
>
> In file included from /nix/store/bvffdqfhyxvx66bqlqqdmjmkyklkafv6-musl-1.2.5-dev/include/netinet/et…
> from /nix/store/kz6fymqpgbrj6330s6wv4idcf9pwsqs4-iptables-1.8.10-de…
> from src/xt.c:30:
> /nix/store/bvffdqfhyxvx66bqlqqdmjmkyklkafv6-musl-1.2.5-dev/include/netinet/if_ether.h:115:8: error: redefinition of 'struct ethhdr'
> 115 | struct ethhdr {
> | ^~~~~~
> In file included from ./include/linux/netfilter_bridge.h:8,
> from ./include/linux/netfilter_bridge/ebtables.h:1,
> from src/xt.c:27:
> /nix/store/bvffdqfhyxvx66bqlqqdmjmkyklkafv6-musl-1.2.5-dev/include/linux/if_ether.h:173:8: note: originally defined here
> 173 | struct ethhdr {
> | ^~~~~~
>
> The fix is to use libc's version of if_ether.h before any kernel
> headers, which takes care of conflicts with the kernel's struct ethhdr
> definition by defining __UAPI_DEF_ETHHDR, which will tell the kernel's
> header not to define its own version.
What I don't like about this is how musl tries to force projects to not
include linux/if_ether.h directly. From the project's view, this is a
workaround not a fix.
> Signed-off-by: Alyssa Ross <hi@xxxxxxxxx>
> ---
> A similar fix would solve the problem properly in iptables, which was
> worked around with 76fce228 ("configure: Determine if musl is used for build").
> The __UAPI_DEF_ETHHDR is supposed to be set by netinet/if_ether.h,
> rather than manually by users.
Why does 76fce228 not work for you?
Cheers, Phil
