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!
