On 10/03/2018 07:32 AM, Joe Stringer wrote:
> Stephen Rothwell reports the following link failure with IPv6 as module:
>
> x86_64-linux-gnu-ld: net/core/filter.o: in function `sk_lookup':
> (.text+0x19219): undefined reference to `__udp6_lib_lookup'
>
> Fix the build by only enabling the IPv6 socket lookup if IPv6 support is
> compiled into the kernel.
>
> Signed-off-by: Joe Stringer <j...@wand.net.nz>
> ---
> net/core/filter.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 591c698bc517..30c6b2d3ef16 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -4838,7 +4838,7 @@ struct sock *sk_lookup(struct net *net, struct
> bpf_sock_tuple *tuple,
> sk = __udp4_lib_lookup(net, src4, tuple->ipv4.sport,
> dst4, tuple->ipv4.dport,
> dif, sdif, &udp_table, skb);
> -#if IS_ENABLED(CONFIG_IPV6)
> +#if IS_REACHABLE(CONFIG_IPV6)
> } else {
> struct in6_addr *src6 = (struct in6_addr *)&tuple->ipv6.saddr;
> struct in6_addr *dst6 = (struct in6_addr *)&tuple->ipv6.daddr;
>
Applied as a quick fix, thanks Joe, but ideally this should also work when ipv6
is compiled as a module. There's the ipv6_bpf_stub, which does that job for
other
helpers that would call into v6 code out of the builtin filter.c, so I think we
should follow the same approach here as well. See commit d74bad4e74ee ("bpf:
Hooks for sys_connect").
Thanks,
Daniel
