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Tue, 28 Apr 2020 11:31:37 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk ([45.145.92.2]) by smtp.gmail.com with ESMTPSA id d23sm14692884ljg.90.2020.04.28.11.31.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2020 11:31:36 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 87A941814FF; Tue, 28 Apr 2020 20:31:35 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Andrii Nakryiko Cc: Andrii Nakryiko , bpf , Networking , Alexei Starovoitov , Daniel Borkmann , Kernel Team Subject: Re: [PATCH v2 bpf-next 04/10] bpf: add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link In-Reply-To: References: <20200428054944.4015462-1-andriin@fb.com> <20200428054944.4015462-5-andriin@fb.com> <87mu6wvt6t.fsf@toke.dk> X-Clacks-Overhead: GNU Terry Pratchett Date: Tue, 28 Apr 2020 20:31:35 +0200 Message-ID: <87v9ljv4vs.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Andrii Nakryiko writes: > On Tue, Apr 28, 2020 at 2:46 AM Toke H=C3=B8iland-J=C3=B8rgensen wrote: >> >> Andrii Nakryiko writes: >> >> > Add ability to fetch bpf_link details through BPF_OBJ_GET_INFO_BY_FD c= ommand. >> > Also enhance show_fdinfo to potentially include bpf_link type-specific >> > information (similarly to obj_info). >> > >> > Also introduce enum bpf_link_type stored in bpf_link itself and expose= it in >> > UAPI. bpf_link_tracing also now will store and return bpf_attach_type. >> > >> > Signed-off-by: Andrii Nakryiko >> > --- >> > include/linux/bpf-cgroup.h | 2 - >> > include/linux/bpf.h | 10 +- >> > include/linux/bpf_types.h | 6 ++ >> > include/uapi/linux/bpf.h | 28 ++++++ >> > kernel/bpf/btf.c | 2 + >> > kernel/bpf/cgroup.c | 45 ++++++++- >> > kernel/bpf/syscall.c | 164 +++++++++++++++++++++++++++++---- >> > kernel/bpf/verifier.c | 2 + >> > tools/include/uapi/linux/bpf.h | 31 +++++++ >> > 9 files changed, 266 insertions(+), 24 deletions(-) >> > >> > diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h >> > index d2d969669564..ab95824a1d99 100644 >> > --- a/include/linux/bpf-cgroup.h >> > +++ b/include/linux/bpf-cgroup.h >> > @@ -57,8 +57,6 @@ struct bpf_cgroup_link { >> > enum bpf_attach_type type; >> > }; >> > >> > -extern const struct bpf_link_ops bpf_cgroup_link_lops; >> > - >> > struct bpf_prog_list { >> > struct list_head node; >> > struct bpf_prog *prog; >> > diff --git a/include/linux/bpf.h b/include/linux/bpf.h >> > index 875d1f0af803..701c4387c711 100644 >> > --- a/include/linux/bpf.h >> > +++ b/include/linux/bpf.h >> > @@ -1026,9 +1026,11 @@ extern const struct file_operations bpf_prog_fo= ps; >> > extern const struct bpf_verifier_ops _name ## _verifier_ops; >> > #define BPF_MAP_TYPE(_id, _ops) \ >> > extern const struct bpf_map_ops _ops; >> > +#define BPF_LINK_TYPE(_id, _name) >> > #include >> > #undef BPF_PROG_TYPE >> > #undef BPF_MAP_TYPE >> > +#undef BPF_LINK_TYPE >> > >> > extern const struct bpf_prog_ops bpf_offload_prog_ops; >> > extern const struct bpf_verifier_ops tc_cls_act_analyzer_ops; >> > @@ -1086,6 +1088,7 @@ int bpf_prog_new_fd(struct bpf_prog *prog); >> > struct bpf_link { >> > atomic64_t refcnt; >> > u32 id; >> > + enum bpf_link_type type; >> > const struct bpf_link_ops *ops; >> > struct bpf_prog *prog; >> > struct work_struct work; >> > @@ -1103,9 +1106,14 @@ struct bpf_link_ops { >> > void (*dealloc)(struct bpf_link *link); >> > int (*update_prog)(struct bpf_link *link, struct bpf_prog *new_p= rog, >> > struct bpf_prog *old_prog); >> > + void (*show_fdinfo)(const struct bpf_link *link, struct seq_file= *seq); >> > + int (*fill_link_info)(const struct bpf_link *link, >> > + struct bpf_link_info *info, >> > + const struct bpf_link_info *uinfo, >> > + u32 info_len); >> > }; >> > >> > -void bpf_link_init(struct bpf_link *link, >> > +void bpf_link_init(struct bpf_link *link, enum bpf_link_type type, >> > const struct bpf_link_ops *ops, struct bpf_prog *prog= ); >> > int bpf_link_prime(struct bpf_link *link, struct bpf_link_primer *pri= mer); >> > int bpf_link_settle(struct bpf_link_primer *primer); >> > diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h >> > index ba0c2d56f8a3..8345cdf553b8 100644 >> > --- a/include/linux/bpf_types.h >> > +++ b/include/linux/bpf_types.h >> > @@ -118,3 +118,9 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops) >> > #if defined(CONFIG_BPF_JIT) >> > BPF_MAP_TYPE(BPF_MAP_TYPE_STRUCT_OPS, bpf_struct_ops_map_ops) >> > #endif >> > + >> > +BPF_LINK_TYPE(BPF_LINK_TYPE_RAW_TRACEPOINT, raw_tracepoint) >> > +BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing) >> > +#ifdef CONFIG_CGROUP_BPF >> > +BPF_LINK_TYPE(BPF_LINK_TYPE_CGROUP, cgroup) >> > +#endif >> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h >> > index 7e6541fceade..0eccafae55bb 100644 >> > --- a/include/uapi/linux/bpf.h >> > +++ b/include/uapi/linux/bpf.h >> > @@ -222,6 +222,15 @@ enum bpf_attach_type { >> > >> > #define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE >> > >> > +enum bpf_link_type { >> > + BPF_LINK_TYPE_UNSPEC =3D 0, >> > + BPF_LINK_TYPE_RAW_TRACEPOINT =3D 1, >> > + BPF_LINK_TYPE_TRACING =3D 2, >> > + BPF_LINK_TYPE_CGROUP =3D 3, >> > + >> > + MAX_BPF_LINK_TYPE, >> > +}; >> > + >> > /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command >> > * >> > * NONE(default): No further bpf programs allowed in the subtree. >> > @@ -3612,6 +3621,25 @@ struct bpf_btf_info { >> > __u32 id; >> > } __attribute__((aligned(8))); >> > >> > +struct bpf_link_info { >> > + __u32 type; >> > + __u32 id; >> > + __u32 prog_id; >> > + union { >> > + struct { >> > + __aligned_u64 tp_name; /* in/out: tp_name buffer= ptr */ >> > + __u32 tp_name_len; /* in/out: tp_name buffer= len */ >> > + } raw_tracepoint; >> > + struct { >> > + __u32 attach_type; >> > + } tracing; >> >> On the RFC I asked whether we could get the attach target here as well. >> You said you'd look into it; what happened to that? :) >> > > Right, sorry, forgot to mention this. I did take a look, but tracing > links are quite diverse, so I didn't see one clear way to structure > such "target" information, so I'd say we should push it into a > separate patch/discussion. E.g., fentry/fexit/fmod_exit are attached > to kernel functions (how do we represent that), freplace are attached > to another BPF program (this is a bit clearer how to represent, but > how do we combine that with fentry/fexit info?). LSM is also attached > to kernel function, but who knows, maybe we want slightly more > extended semantics for it. Either way, I don't see one best way to > structure this information and would want to avoid blocking on this > for this series. Also bpf_link_info is extensible, so it's not a > problem to extend it in follow up patches. > > Does it make sense? Yup, fair enough, I can live with deferring this to a later series :) -Toke