From: Yonghong Song <yhs@fb.com>
To: Kumar Kartikeya Dwivedi <memxor@gmail.com>, <bpf@vger.kernel.org>
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Martin KaFai Lau" <kafai@fb.com>,
"Song Liu" <songliubraving@fb.com>,
"John Fastabend" <john.fastabend@gmail.com>,
"KP Singh" <kpsingh@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
netdev@vger.kernel.org
Subject: Re: [PATCH bpf-next v3 2/3] libbpf: add low level TC-BPF API
Date: Tue, 20 Apr 2021 23:58:01 -0700 [thread overview]
Message-ID: <27b90b27-ce90-7b2c-23be-24cbc0781fbe@fb.com> (raw)
In-Reply-To: <20210420193740.124285-3-memxor@gmail.com>
On 4/20/21 12:37 PM, Kumar Kartikeya Dwivedi wrote:
> This adds functions that wrap the netlink API used for adding,
> manipulating, and removing traffic control filters. These functions
> operate directly on the loaded prog's fd, and return a handle to the
> filter using an out parameter named id.
>
> The basic featureset is covered to allow for attaching and removal of
> filters. Some additional features like TCA_BPF_POLICE and TCA_RATE for
> the API have been omitted. These can added on top later by extending the
"later" => "layer"?
> bpf_tc_opts struct.
>
> Support for binding actions directly to a classifier by passing them in
> during filter creation has also been omitted for now. These actions have
> an auto clean up property because their lifetime is bound to the filter
> they are attached to. This can be added later, but was omitted for now
> as direct action mode is a better alternative to it, which is enabled by
> default.
>
> An API summary:
>
> bpf_tc_attach may be used to attach, and replace SCHED_CLS bpf
> classifier. The protocol is always set as ETH_P_ALL. The replace option
> in bpf_tc_opts is used to control replacement behavior. Attachment
> fails if filter with existing attributes already exists.
>
> bpf_tc_detach may be used to detach existing SCHED_CLS filter. The
> bpf_tc_attach_id object filled in during attach must be passed in to the
> detach functions for them to remove the filter and its attached
> classififer correctly.
>
> bpf_tc_get_info is a helper that can be used to obtain attributes
> for the filter and classififer.
>
> Examples:
>
> struct bpf_tc_attach_id id = {};
> struct bpf_object *obj;
> struct bpf_program *p;
> int fd, r;
>
> obj = bpf_object_open("foo.o");
> if (IS_ERR_OR_NULL(obj))
> return PTR_ERR(obj);
>
> p = bpf_object__find_program_by_title(obj, "classifier");
Please use bpf_object__find_program_by_name() API.
bpf_object__find_program_by_title() is not recommended as now
libbpf supports multiple programs within the same section.
> if (IS_ERR_OR_NULL(p))
> return PTR_ERR(p);
>
> if (bpf_object__load(obj) < 0)
> return -1;
>
> fd = bpf_program__fd(p);
>
> r = bpf_tc_attach(fd, if_nametoindex("lo"),
> BPF_TC_CLSACT_INGRESS,
> NULL, &id);
> if (r < 0)
> return r;
>
> ... which is roughly equivalent to:
> # tc qdisc add dev lo clsact
> # tc filter add dev lo ingress bpf obj foo.o sec classifier da
>
> ... as direct action mode is always enabled.
>
> To replace an existing filter:
>
> DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .handle = id.handle,
> .priority = id.priority, .replace = true);
> r = bpf_tc_attach(fd, if_nametoindex("lo"),
> BPF_TC_CLSACT_INGRESS,
> &opts, &id);
> if (r < 0)
> return r;
>
> To obtain info of a particular filter, the example above can be extended
> as follows:
>
> struct bpf_tc_info info = {};
>
> r = bpf_tc_get_info(if_nametoindex("lo"),
> BPF_TC_CLSACT_INGRESS,
> &id, &info);
> if (r < 0)
> return r;
>
> ... where id corresponds to the bpf_tc_attach_id filled in during an
> attach operation.
>
> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
> ---
> tools/lib/bpf/libbpf.h | 44 ++++++
> tools/lib/bpf/libbpf.map | 3 +
> tools/lib/bpf/netlink.c | 319 ++++++++++++++++++++++++++++++++++++++-
> 3 files changed, 360 insertions(+), 6 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index bec4e6a6e31d..b4ed6a41ea70 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -16,6 +16,8 @@
> #include <stdbool.h>
> #include <sys/types.h> // for size_t
> #include <linux/bpf.h>
> +#include <linux/pkt_sched.h>
> +#include <linux/tc_act/tc_bpf.h>
>
> #include "libbpf_common.h"
>
> @@ -775,6 +777,48 @@ LIBBPF_API int bpf_linker__add_file(struct bpf_linker *linker, const char *filen
> LIBBPF_API int bpf_linker__finalize(struct bpf_linker *linker);
> LIBBPF_API void bpf_linker__free(struct bpf_linker *linker);
>
> +/* Convenience macros for the clsact attach hooks */
> +#define BPF_TC_CLSACT_INGRESS TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS)
> +#define BPF_TC_CLSACT_EGRESS TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS)
> +
> +struct bpf_tc_opts {
> + size_t sz;
> + __u32 handle;
> + __u32 class_id;
> + __u16 priority;
> + bool replace;
> + size_t :0;
Did you see any error without "size_t :0"?
> +};
> +
> +#define bpf_tc_opts__last_field replace
> +
> +/* Acts as a handle for an attached filter */
> +struct bpf_tc_attach_id {
> + __u32 handle;
> + __u16 priority;
> +};
> +
[...]
next prev parent reply other threads:[~2021-04-21 6:58 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-20 19:37 [PATCH bpf-next v3 0/3] Add TC-BPF API Kumar Kartikeya Dwivedi
2021-04-20 19:37 ` [PATCH bpf-next v3 1/3] libbpf: add helpers for preparing netlink attributes Kumar Kartikeya Dwivedi
2021-04-21 6:37 ` Yonghong Song
2021-04-20 19:37 ` [PATCH bpf-next v3 2/3] libbpf: add low level TC-BPF API Kumar Kartikeya Dwivedi
2021-04-21 6:58 ` Yonghong Song [this message]
2021-04-21 17:06 ` Kumar Kartikeya Dwivedi
2021-04-22 1:56 ` Yonghong Song
2021-04-21 18:19 ` Andrii Nakryiko
2021-04-21 19:48 ` Toke Høiland-Jørgensen
2021-04-21 23:14 ` Daniel Borkmann
2021-04-22 9:08 ` Toke Høiland-Jørgensen
2021-04-22 11:51 ` Daniel Borkmann
2021-04-22 12:46 ` Toke Høiland-Jørgensen
2021-04-21 22:59 ` Daniel Borkmann
2021-04-21 23:08 ` Kumar Kartikeya Dwivedi
2021-04-21 23:21 ` Daniel Borkmann
2021-04-21 23:30 ` Kumar Kartikeya Dwivedi
2021-04-21 23:41 ` Daniel Borkmann
2021-04-22 9:47 ` Shaun Crampton
2021-04-22 11:26 ` Daniel Borkmann
2021-04-22 3:43 ` Andrii Nakryiko
2021-04-22 15:35 ` Daniel Borkmann
2021-04-22 18:28 ` Andrii Nakryiko
2021-04-20 19:37 ` [PATCH bpf-next v3 3/3] libbpf: add selftests for " Kumar Kartikeya Dwivedi
2021-04-21 7:01 ` Yonghong Song
2021-04-21 18:24 ` Andrii Nakryiko
2021-04-21 19:56 ` Kumar Kartikeya Dwivedi
2021-04-21 20:38 ` Toke Høiland-Jørgensen
2021-04-21 22:41 ` Daniel Borkmann
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=27b90b27-ce90-7b2c-23be-24cbc0781fbe@fb.com \
--to=yhs@fb.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=brouer@redhat.com \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=kpsingh@kernel.org \
--cc=kuba@kernel.org \
--cc=memxor@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=songliubraving@fb.com \
--cc=toke@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).