Re: [PATCH bpf-next v3] selftests/bpf: fix compilation failure when CONFIG_NET_FOU!=y

[Andrii Nakryiko]

On Tue, Jul 23, 2024 at 12:10 AM Artem Savkov <asavkov@xxxxxxxxxx> wrote:
>
> Without CONFIG_NET_FOU bpf selftests are unable to build because of
> missing definitions. Add ___local versions of struct bpf_fou_encap and
> enum bpf_fou_encap_type to fix the issue.
>
> Signed-off-by: Artem Savkov <asavkov@xxxxxxxxxx>
>
> ---
> v3: swith from using BPF_NO_KFUNC_PROTOTYPES to casting to keep kfunc
> prototype intact.
>
> v2: added BPF_NO_KFUNC_PROTOTYPES define to avoid issues when
> CONFIG_NET_FOU is set.
> ---
>  .../selftests/bpf/progs/test_tunnel_kern.c    | 26 ++++++++++++++-----
>  1 file changed, 20 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
> index 3f5abcf3ff136..fcff3010d8a60 100644
> --- a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
> +++ b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
> @@ -26,6 +26,18 @@
>   */
>  #define ASSIGNED_ADDR_VETH1 0xac1001c8
>
> +struct bpf_fou_encap___local {
> +       __be16 sport;
> +       __be16 dport;
> +};
> +
> +enum bpf_fou_encap_type___local {
> +       FOU_BPF_ENCAP_FOU___local,
> +       FOU_BPF_ENCAP_GUE___local,
> +};

both of the above are internal kernel types (not UAPI ones), so I
added preserve_access_index to the struct and ...

> +
> +struct bpf_fou_encap;
> +
>  int bpf_skb_set_fou_encap(struct __sk_buff *skb_ctx,
>                           struct bpf_fou_encap *encap, int type) __ksym;
>  int bpf_skb_get_fou_encap(struct __sk_buff *skb_ctx,
> @@ -745,7 +757,7 @@ SEC("tc")
>  int ipip_gue_set_tunnel(struct __sk_buff *skb)
>  {
>         struct bpf_tunnel_key key = {};
> -       struct bpf_fou_encap encap = {};
> +       struct bpf_fou_encap___local encap = {};
>         void *data = (void *)(long)skb->data;
>         struct iphdr *iph = data;
>         void *data_end = (void *)(long)skb->data_end;
> @@ -769,7 +781,8 @@ int ipip_gue_set_tunnel(struct __sk_buff *skb)
>         encap.sport = 0;
>         encap.dport = bpf_htons(5555);
>
> -       ret = bpf_skb_set_fou_encap(skb, &encap, FOU_BPF_ENCAP_GUE);
> +       ret = bpf_skb_set_fou_encap(skb, (struct bpf_fou_encap *)&encap,
> +                                   FOU_BPF_ENCAP_GUE___local);
>         if (ret < 0) {
>                 log_err(ret);
>                 return TC_ACT_SHOT;
> @@ -782,7 +795,7 @@ SEC("tc")
>  int ipip_fou_set_tunnel(struct __sk_buff *skb)
>  {
>         struct bpf_tunnel_key key = {};
> -       struct bpf_fou_encap encap = {};
> +       struct bpf_fou_encap___local encap = {};
>         void *data = (void *)(long)skb->data;
>         struct iphdr *iph = data;
>         void *data_end = (void *)(long)skb->data_end;
> @@ -806,7 +819,8 @@ int ipip_fou_set_tunnel(struct __sk_buff *skb)
>         encap.sport = 0;
>         encap.dport = bpf_htons(5555);
>
> -       ret = bpf_skb_set_fou_encap(skb, &encap, FOU_BPF_ENCAP_FOU);
> +       ret = bpf_skb_set_fou_encap(skb, (struct bpf_fou_encap *)&encap,
> +                                   FOU_BPF_ENCAP_FOU___local);


use bpf_core_enum_value() here for getting enum value in CO-RE-relocatable way

(also fixed spaces vs tabs issue that were pointed out)

pushed to bpf-next


>         if (ret < 0) {
>                 log_err(ret);
>                 return TC_ACT_SHOT;
> @@ -820,7 +834,7 @@ int ipip_encap_get_tunnel(struct __sk_buff *skb)
>  {
>         int ret;
>         struct bpf_tunnel_key key = {};
> -       struct bpf_fou_encap encap = {};
> +       struct bpf_fou_encap___local encap = {};
>
>         ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
>         if (ret < 0) {
> @@ -828,7 +842,7 @@ int ipip_encap_get_tunnel(struct __sk_buff *skb)
>                 return TC_ACT_SHOT;
>         }
>
> -       ret = bpf_skb_get_fou_encap(skb, &encap);
> +       ret = bpf_skb_get_fou_encap(skb, (struct bpf_fou_encap *)&encap);
>         if (ret < 0) {
>                 log_err(ret);
>                 return TC_ACT_SHOT;
> --
> 2.45.2
>