netdev - Re: [PATCH v2 bpf-next 0/7] Add __sk_buff->sk, bpf_tcp_sock, BPF_FUNC_tcp_sock and BPF_FUNC_sk

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Date:   Mon, 11 Feb 2019 15:56:17 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>,
        Martin KaFai Lau <kafai@...com>
Cc:     netdev@...r.kernel.org, Alexei Starovoitov <ast@...com>,
        kernel-team@...com, Lawrence Brakmo <brakmo@...com>
Subject: Re: [PATCH v2 bpf-next 0/7] Add __sk_buff->sk, bpf_tcp_sock,
 BPF_FUNC_tcp_sock and BPF_FUNC_sk_fullsock

On 02/11/2019 04:55 AM, Alexei Starovoitov wrote:
> On Sat, Feb 09, 2019 at 11:22:20PM -0800, Martin KaFai Lau wrote:
>> This series adds __sk_buff->sk, "struct bpf_tcp_sock",
>> BPF_FUNC_sk_fullsock and BPF_FUNC_tcp_sock.  Together, they provide
>> a common way to expose the members of "struct tcp_sock" and
>> "struct bpf_sock" for the bpf_prog to access.
>>
>> The patch series first adds a bpf_sock pointer to __sk_buff
>> and a new helper BPF_FUNC_sk_fullsock.
>>
>> It then adds BPF_FUNC_tcp_sock to get a bpf_tcp_sock
>> pointer from a bpf_sock pointer.
>>
>> The current use case is to allow a cg_skb_bpf_prog to provide
>> per cgroup traffic policing/shaping.
>>
>> Please see individual patch for details.
>>
>> v2:
>> - Patch 1 depends on
>>   commit d623876646be ("bpf: Fix narrow load on a bpf_sock returned from sk_lookup()")
>>   in the bpf branch.
>> - Add sk_to_full_sk() to bpf_sk_fullsock() and bpf_tcp_sock()
>>   such that there is a way to access the listener's sk and tcp_sk
>>   when __sk_buff->sk is a request_sock.
>>   The comments in the uapi bpf.h is updated accordingly.
>> - bpf_ctx_range_till() is used in bpf_sock_common_is_valid_access()
>>   in patch 1.  Saved a few lines.
>> - Patch 2 is new in v2 and it adds "state", "dst_ip4", "dst_ip6" and
>>   "dst_port" to the bpf_sock.  Narrow load is allowed on them.
>>   The "state" (i.e. sk_state) has already been used in
>>   INET_DIAG (e.g. ss -t) and getsockopt(TCP_INFO).
>> - While at it in the new patch 2, also allow narrow load on some
>>   existing fields of the bpf_sock, which are "family", "type", "protocol"
>>   and "src_port".  Only allow loading from first byte for now.
>>   i.e. does not allow narrow load starting from the 2nd byte.
>> - Add some narrow load tests to the test_verifier's sock.c
> 
> Daniel,
> I believe this new revision addresses your concerns exactly as we discussed.
> So I pushed it to bpf-next.
> please double check that it's what you expected.
> We can always revert.
> Thanks everyone!

Yep, looks better, thanks!