From: Daniel Borkmann <daniel@iogearbox.net>
To: brakmo <brakmo@fb.com>, netdev <netdev@vger.kernel.org>
Cc: Martin Lau <kafai@fb.com>, Alexei Starovoitov <ast@fb.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
Kernel Team <Kernel-team@fb.com>
Subject: Re: [PATCH v2 bpf-next 4/9] bpf: add bpf helper bpf_skb_ecn_set_ce
Date: Sat, 23 Feb 2019 02:14:26 +0100 [thread overview]
Message-ID: <fdcd5fbb-0f51-18f9-a13a-52e8009d082e@iogearbox.net> (raw)
In-Reply-To: <20190223010703.678070-5-brakmo@fb.com>
On 02/23/2019 02:06 AM, brakmo wrote:
> This patch adds a new bpf helper BPF_FUNC_skb_ecn_set_ce
> "int bpf_skb_ecn_set_ce(struct sk_buff *skb)". It is added to
> BPF_PROG_TYPE_CGROUP_SKB typed bpf_prog which currently can
> be attached to the ingress and egress path. The helper is needed
> because his type of bpf_prog cannot modify the skb directly.
>
> This helper is used to set the ECN field of ECN capable IP packets to ce
> (congestion encountered) in the IPv6 or IPv4 header of the skb. It can be
> used by a bpf_prog to manage egress or ingress network bandwdith limit
> per cgroupv2 by inducing an ECN response in the TCP sender.
> This works best when using DCTCP.
>
> Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
> ---
> include/uapi/linux/bpf.h | 10 +++++++++-
> net/core/filter.c | 14 ++++++++++++++
> 2 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 95b5058fa945..fc646f3eaf9b 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -2365,6 +2365,13 @@ union bpf_attr {
> * Make a tcp_sock enter CWR state.
> * Return
> * 0 on success, or a negative error in case of failure.
> + *
> + * int bpf_skb_ecn_set_ce(struct sk_buf *skb)
> + * Description
> + * Sets ECN of IP header to ce (congestion encountered) if
> + * current value is ect (ECN capable). Works with IPv6 and IPv4.
> + * Return
> + * 1 if set, 0 if not set.
> */
> #define __BPF_FUNC_MAPPER(FN) \
> FN(unspec), \
> @@ -2464,7 +2471,8 @@ union bpf_attr {
> FN(spin_unlock), \
> FN(sk_fullsock), \
> FN(tcp_sock), \
> - FN(tcp_enter_cwr),
> + FN(tcp_enter_cwr), \
> + FN(skb_ecn_set_ce),
>
> /* integer value in 'imm' field of BPF_CALL instruction selects which helper
> * function eBPF program intends to call
> diff --git a/net/core/filter.c b/net/core/filter.c
> index ca57ef25279c..955369c6ed30 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -5444,6 +5444,18 @@ static const struct bpf_func_proto bpf_tcp_enter_cwr_proto = {
> .ret_type = RET_INTEGER,
> .arg1_type = ARG_PTR_TO_TCP_SOCK,
> };
> +
> +BPF_CALL_1(bpf_skb_ecn_set_ce, struct sk_buff *, skb)
> +{
> + return INET_ECN_set_ce(skb);
Hm, but as mentioned last time, don't we have to ensure here that skb
is writable (aka skb->data private to us before writing into it)?
> +}
> +
> +static const struct bpf_func_proto bpf_skb_ecn_set_ce_proto = {
> + .func = bpf_skb_ecn_set_ce,
> + .gpl_only = false,
> + .ret_type = RET_INTEGER,
> + .arg1_type = ARG_PTR_TO_CTX,
> +};
> #endif /* CONFIG_INET */
>
> bool bpf_helper_changes_pkt_data(void *func)
> @@ -5610,6 +5622,8 @@ cg_skb_func_proto(enum bpf_func_id func_id, struct bpf_prog *prog)
> } else {
> return NULL;
> }
> + case BPF_FUNC_skb_ecn_set_ce:
> + return &bpf_skb_ecn_set_ce_proto;
> #endif
> default:
> return sk_filter_func_proto(func_id, prog);
>
Thanks,
Daniel
next prev parent reply other threads:[~2019-02-23 1:14 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-23 1:06 [PATCH v2 bpf-next 0/9] bpf: Network Resource Manager (NRM) brakmo
2019-02-23 1:06 ` [PATCH v2 bpf-next 1/9] bpf: Remove const from get_func_proto brakmo
2019-02-23 1:06 ` [PATCH v2 bpf-next 2/9] bpf: Add bpf helper bpf_tcp_enter_cwr brakmo
2019-02-24 1:32 ` Eric Dumazet
2019-02-24 3:08 ` Martin Lau
2019-02-24 4:44 ` Alexei Starovoitov
2019-02-24 18:00 ` Eric Dumazet
2019-02-25 23:14 ` Stanislav Fomichev
2019-02-26 1:30 ` Martin Lau
2019-02-26 3:32 ` Stanislav Fomichev
2019-02-23 1:06 ` [PATCH v2 bpf-next 3/9] bpf: Test bpf_tcp_enter_cwr in test_verifier brakmo
2019-02-23 1:06 ` [PATCH v2 bpf-next 4/9] bpf: add bpf helper bpf_skb_ecn_set_ce brakmo
2019-02-23 1:14 ` Daniel Borkmann [this message]
2019-02-23 7:30 ` Martin Lau
2019-02-25 10:10 ` Daniel Borkmann
2019-02-25 16:52 ` Eric Dumazet
2019-02-23 1:06 ` [PATCH v2 bpf-next 5/9] bpf: Add bpf helper bpf_tcp_check_probe_timer brakmo
2019-02-23 1:07 ` [PATCH v2 bpf-next 6/9] bpf: sync bpf.h to tools and update bpf_helpers.h brakmo
2019-02-23 1:07 ` [PATCH v2 bpf-next 7/9] bpf: Sample NRM BPF program to limit egress bw brakmo
2019-02-23 1:07 ` [PATCH v2 bpf-next 8/9] bpf: User program for testing NRM brakmo
2019-02-23 1:07 ` [PATCH v2 bpf-next 9/9] bpf: NRM test script brakmo
2019-02-23 3:03 ` [PATCH v2 bpf-next 0/9] bpf: Network Resource Manager (NRM) David Ahern
2019-02-23 18:39 ` Eric Dumazet
2019-02-23 20:40 ` Alexei Starovoitov
2019-02-23 20:43 ` Eric Dumazet
2019-02-23 23:25 ` Alexei Starovoitov
2019-02-24 2:58 ` David Ahern
2019-02-24 4:48 ` Alexei Starovoitov
2019-02-25 1:38 ` David Ahern
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