Re: [PATCH bpf-next v5 2/5] libbpf: Add bpf_link support for BPF_PROG_TYPE_SOCKMAP

[Yonghong Song <yonghong.song@linux.dev>]

On 4/6/24 11:49 AM, Andrii Nakryiko wrote:
> On Sat, Apr 6, 2024 at 9:04 AM Yonghong Song <yonghong.song@linux.dev> wrote:
>> Introduce a libbpf API function bpf_program__attach_sockmap()
>> which allow user to get a bpf_link for their corresponding programs.
>>
>> Acked-by: Andrii Nakryiko <andrii@kernel.org>
>> Acked-by: Eduard Zingerman <eddyz87@gmail.com>
>> Reviewed-by: John Fastabend <john.fastabend@gmail.com>
>> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
>> ---
>>   tools/lib/bpf/libbpf.c         | 7 +++++++
>>   tools/lib/bpf/libbpf.h         | 2 ++
>>   tools/lib/bpf/libbpf.map       | 5 +++++
>>   tools/lib/bpf/libbpf_version.h | 2 +-
>>   4 files changed, 15 insertions(+), 1 deletion(-)
>>
> I feel like I mentioned this before, but maybe not. Besides there
> high-level attach APIs, please also add bpf_link_create() support, it
> should be very straightforward, just follow the pattern for other link
> types.

I checked bpf_link_create() in bpf.c. bpf_link_create() works now
without any additional change sicne it does not need to set anything
in option arguments. I will add a test to use bpf_link_create()
for one of sk_msg or sk_skb programs.

>
> You'll also get a conflict in libbpf.map given I just applied another
> libbpf patches (ring_buffer__consume_n). So please rebase.

Ack.

>
> pw-bot: cr
>
>> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
>> index b091154bc5b5..97eb6e5dd7c8 100644
>> --- a/tools/lib/bpf/libbpf.c
>> +++ b/tools/lib/bpf/libbpf.c
>> @@ -149,6 +149,7 @@ static const char * const link_type_name[] = {
>>          [BPF_LINK_TYPE_TCX]                     = "tcx",
>>          [BPF_LINK_TYPE_UPROBE_MULTI]            = "uprobe_multi",
>>          [BPF_LINK_TYPE_NETKIT]                  = "netkit",
>> +       [BPF_LINK_TYPE_SOCKMAP]                 = "sockmap",
>>   };
>>
>>   static const char * const map_type_name[] = {
>> @@ -12533,6 +12534,12 @@ bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd)
>>          return bpf_program_attach_fd(prog, netns_fd, "netns", NULL);
>>   }
>>
>> +struct bpf_link *
>> +bpf_program__attach_sockmap(const struct bpf_program *prog, int map_fd)
>> +{
>> +       return bpf_program_attach_fd(prog, map_fd, "sockmap", NULL);
>> +}
>> +
>>   struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex)
>>   {
>>          /* target_fd/target_ifindex use the same field in LINK_CREATE */
>> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
>> index f88ab50c0229..4c7ada03bf4f 100644
>> --- a/tools/lib/bpf/libbpf.h
>> +++ b/tools/lib/bpf/libbpf.h
>> @@ -795,6 +795,8 @@ bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd);
>>   LIBBPF_API struct bpf_link *
>>   bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd);
>>   LIBBPF_API struct bpf_link *
>> +bpf_program__attach_sockmap(const struct bpf_program *prog, int map_fd);
>> +LIBBPF_API struct bpf_link *
>>   bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex);
>>   LIBBPF_API struct bpf_link *
>>   bpf_program__attach_freplace(const struct bpf_program *prog,
>> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
>> index 51732ecb1385..2d0ca3e8ec18 100644
>> --- a/tools/lib/bpf/libbpf.map
>> +++ b/tools/lib/bpf/libbpf.map
>> @@ -416,3 +416,8 @@ LIBBPF_1.4.0 {
>>                  btf__new_split;
>>                  btf_ext__raw_data;
>>   } LIBBPF_1.3.0;
>> +
>> +LIBBPF_1.5.0 {
>> +       global:
>> +               bpf_program__attach_sockmap;
>> +} LIBBPF_1.4.0;
>> diff --git a/tools/lib/bpf/libbpf_version.h b/tools/lib/bpf/libbpf_version.h
>> index e783a47da815..d6e5eff967cb 100644
>> --- a/tools/lib/bpf/libbpf_version.h
>> +++ b/tools/lib/bpf/libbpf_version.h
>> @@ -4,6 +4,6 @@
>>   #define __LIBBPF_VERSION_H
>>
>>   #define LIBBPF_MAJOR_VERSION 1
>> -#define LIBBPF_MINOR_VERSION 4
>> +#define LIBBPF_MINOR_VERSION 5
>>
>>   #endif /* __LIBBPF_VERSION_H */
>> --
>> 2.43.0
>>