From: Daniel Borkmann <daniel@iogearbox•net>
To: Alexei Starovoitov <alexei.starovoitov@gmail•com>,
Tom Herbert <tom@herbertland•com>
Cc: Brenden Blanco <bblanco@plumgrid•com>,
"David S. Miller" <davem@davemloft•net>,
Linux Kernel Network Developers <netdev@vger•kernel.org>,
Jamal Hadi Salim <jhs@mojatatu•com>,
Saeed Mahameed <saeedm@dev•mellanox.co.il>,
Martin KaFai Lau <kafai@fb•com>,
Jesper Dangaard Brouer <brouer@redhat•com>,
Ari Saha <as754m@att•com>, Or Gerlitz <gerlitz.or@gmail•com>,
john fastabend <john.fastabend@gmail•com>,
Hannes Frederic Sowa <hannes@stressinduktion•org>,
Thomas Graf <tgraf@suug•ch>,
Tariq Toukan <ttoukan.linux@gmail•com>,
Aaron Yue <haoxuany@fb•com>
Subject: Re: [PATCH v10 12/12] bpf: add sample for xdp forwarding and rewrite
Date: Thu, 04 Aug 2016 01:18:36 +0200 [thread overview]
Message-ID: <57A27BCC.4000608@iogearbox.net> (raw)
In-Reply-To: <20160803223632.GA42605@ast-mbp.thefacebook.com>
On 08/04/2016 12:36 AM, Alexei Starovoitov wrote:
> On Wed, Aug 03, 2016 at 12:06:55PM -0700, Tom Herbert wrote:
[...]
>> This is not at all obvious to XDP programmer. The type of ctx
>> structure is xdp_md and the definition of that structure in
>> uapi/linux/bpf.h says that the fields in the that structure are __u32.
>> So when I, as a user naive the inner workings of the verifier, read
>> this code it sure looks like we are upcasting a 32 bit value to a 64
>> bit value-- that does not seem right at all and the compiler
>> apparently concurs my point of view. If the code ends up being correct
>> anyway, then the obvious answer to have an explicit cast that points
>> out the special nature of this cast. Blindly casting to u32 to long
>> for the purposes of assigning to a pointer is only going to confuse
>> more people as it has me.
>
> Agree. Would be nice to have few helpers. The question is whether
> they belong in bpf.h. Probably not, since they're not kernel abi.
Yeah, fully agree, they don't belong into uapi.
> For the same reasons we didn't include instruction building macros
> like BPF_ALU64_REG and instead kept them in samples/bpf/libbpf.h
+1
> Here probably four static inline functions are needed. Two for __sk_buff
> and two for xpd_md. That should make xdp*_kern.c examples a bit easier
> to read.
Yeah, all these bits should go into some library headers that the test
cases make use of (and make them easier to parse for developers).
next prev parent reply other threads:[~2016-08-03 23:19 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-19 19:16 [PATCH v10 00/12] Add driver bpf hook for early packet drop and forwarding Brenden Blanco
2016-07-19 19:16 ` [PATCH v10 01/12] bpf: add bpf_prog_add api for bulk prog refcnt Brenden Blanco
2016-07-19 21:46 ` Alexei Starovoitov
2016-07-19 19:16 ` [PATCH v10 02/12] bpf: add XDP prog type for early driver filter Brenden Blanco
2016-07-19 21:33 ` Alexei Starovoitov
2016-07-19 19:16 ` [PATCH v10 03/12] net: add ndo to setup/query xdp prog in adapter rx Brenden Blanco
2016-07-19 19:16 ` [PATCH v10 04/12] rtnl: add option for setting link xdp prog Brenden Blanco
2016-07-20 8:38 ` Daniel Borkmann
2016-07-20 17:35 ` Brenden Blanco
2016-07-19 19:16 ` [PATCH v10 05/12] net/mlx4_en: add support for fast rx drop bpf program Brenden Blanco
2016-07-19 21:41 ` Alexei Starovoitov
2016-07-20 9:07 ` Daniel Borkmann
2016-07-20 17:33 ` Brenden Blanco
2016-07-24 11:56 ` Jesper Dangaard Brouer
2016-07-24 16:57 ` Tom Herbert
2016-07-24 20:34 ` Daniel Borkmann
2016-07-19 19:16 ` [PATCH v10 06/12] Add sample for adding simple drop program to link Brenden Blanco
2016-07-19 21:44 ` Alexei Starovoitov
2016-07-19 19:16 ` [PATCH v10 07/12] net/mlx4_en: add page recycle to prepare rx ring for tx support Brenden Blanco
2016-07-19 21:49 ` Alexei Starovoitov
2016-07-25 7:35 ` Eric Dumazet
2016-08-03 17:45 ` order-0 vs order-N driver allocation. Was: " Alexei Starovoitov
2016-08-04 16:19 ` Jesper Dangaard Brouer
2016-08-05 0:30 ` Alexander Duyck
2016-08-05 3:55 ` Alexei Starovoitov
2016-08-05 15:15 ` Alexander Duyck
2016-08-05 15:33 ` David Laight
2016-08-05 16:00 ` Alexander Duyck
2016-08-05 7:15 ` Eric Dumazet
2016-08-08 2:15 ` Alexei Starovoitov
2016-08-08 8:01 ` Jesper Dangaard Brouer
2016-08-08 18:34 ` Alexei Starovoitov
2016-08-09 12:14 ` Jesper Dangaard Brouer
2016-07-19 19:16 ` [PATCH v10 08/12] bpf: add XDP_TX xdp_action for direct forwarding Brenden Blanco
2016-07-19 21:53 ` Alexei Starovoitov
2016-07-19 19:16 ` [PATCH v10 09/12] net/mlx4_en: break out tx_desc write into separate function Brenden Blanco
2016-07-19 19:16 ` [PATCH v10 10/12] net/mlx4_en: add xdp forwarding and data write support Brenden Blanco
2016-07-19 19:16 ` [PATCH v10 11/12] bpf: enable direct packet data write for xdp progs Brenden Blanco
2016-07-19 21:59 ` Alexei Starovoitov
2016-07-19 19:16 ` [PATCH v10 12/12] bpf: add sample for xdp forwarding and rewrite Brenden Blanco
2016-07-19 22:05 ` Alexei Starovoitov
2016-07-20 17:38 ` Brenden Blanco
2016-07-27 18:25 ` Jesper Dangaard Brouer
2016-08-03 17:01 ` Tom Herbert
2016-08-03 17:11 ` Alexei Starovoitov
2016-08-03 17:29 ` Tom Herbert
2016-08-03 18:29 ` David Miller
2016-08-03 18:29 ` Brenden Blanco
2016-08-03 18:31 ` David Miller
2016-08-03 19:06 ` Tom Herbert
2016-08-03 22:36 ` Alexei Starovoitov
2016-08-03 23:18 ` Daniel Borkmann [this message]
2016-07-20 5:09 ` [PATCH v10 00/12] Add driver bpf hook for early packet drop and forwarding David Miller
[not found] ` <6a09ce5d-f902-a576-e44e-8e1e111ae26b@gmail.com>
2016-07-20 14:08 ` Brenden Blanco
2016-07-20 19:14 ` David Miller
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