Yonghong Song wrote:
> libbpf is used as a submodule in bcc.
> When importing latest libbpf repo in bcc, I observed the
> following compilation errors when compiling on ubuntu 16.04.
> .../netlink.c:416:23: error: ‘TC_H_CLSACT’ undeclared (first use in this function)
> *parent = TC_H_MAKE(TC_H_CLSACT,
> ^
> .../netlink.c:418:9: error: ‘TC_H_MIN_INGRESS’ undeclared (first use in this function)
> TC_H_MIN_INGRESS : TC_H_MIN_EGRESS);
> ^
> .../netlink.c:418:28: error: ‘TC_H_MIN_EGRESS’ undeclared (first use in this function)
> TC_H_MIN_INGRESS : TC_H_MIN_EGRESS);
> ^
> .../netlink.c: In function ‘__get_tc_info’:
> .../netlink.c:522:11: error: ‘TCA_BPF_ID’ undeclared (first use in this function)
> if (!tbb[TCA_BPF_ID])
> ^
>
> In ubuntu 16.04, TCA_BPF_* enumerator looks like below
> enum {
> TCA_BPF_UNSPEC,
> TCA_BPF_ACT,
> ...
> TCA_BPF_NAME,
> TCA_BPF_FLAGS,
> __TCA_BPF_MAX,
> };
> #define TCA_BPF_MAX (__TCA_BPF_MAX - 1)
> while in latest bpf-next, the enumerator looks like
> enum {
> TCA_BPF_UNSPEC,
> ...
> TCA_BPF_FLAGS,
> TCA_BPF_FLAGS_GEN,
> TCA_BPF_TAG,
> TCA_BPF_ID,
> __TCA_BPF_MAX,
> };
>
> In this patch, TCA_BPF_ID is defined as a macro with proper value and this
> works regardless of whether TCA_BPF_ID is defined in uapi header or not.
> TCA_BPF_MAX is also adjusted in a similar way.
>
> Fixes: 715c5ce454a6 ("libbpf: Add low level TC-BPF management API")
> Cc: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
> Signed-off-by: Yonghong Song <yhs@xxxxxx>
> ---
Looks better thanks. Now even compiling on systems with out of date
uapi headers should be fine and running on newer kernels will still
work as expected. Thanks.
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
> diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
> index 39f25e09b51e..37cb6b50f4b3 100644
> --- a/tools/lib/bpf/netlink.c
> +++ b/tools/lib/bpf/netlink.c
> @@ -22,6 +22,29 @@
> #define SOL_NETLINK 270
> #endif
>
> +#ifndef TC_H_CLSACT
> +#define TC_H_CLSACT TC_H_INGRESS
> +#endif
> +
> +#ifndef TC_H_MIN_INGRESS
> +#define TC_H_MIN_INGRESS 0xFFF2U
> +#endif
> +
> +#ifndef TC_H_MIN_EGRESS
> +#define TC_H_MIN_EGRESS 0xFFF3U
> +#endif
> +
> +/* TCA_BPF_ID is an enumerator value in uapi/linux/pkt_cls.h.
> + * Declare it as a macro here so old system can still work
> + * without TCA_BPF_ID defined in pkt_cls.h.
> + */
> +#define TCA_BPF_ID 11
I guess compiler is smart enough to see TCA_BPF_ID is the
same value as in headers so it wont throw a redefined warning.
> +
> +#ifdef TCA_BPF_MAX
> +#undef TCA_BPF_MAX
> +#endif
> +#define TCA_BPF_MAX 11
> +
> typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb);
>
> typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, libbpf_dump_nlmsg_t,
> --
> 2.30.2
>
