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From: Martin KaFai Lau <kafai@fb.com>
To: Joe Stringer <joe@wand.net.nz>
Cc: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>,
	<daniel@iogearbox.net>, <ast@kernel.org>,
	<eric.dumazet@gmail.com>, <lmb@cloudflare.com>
Subject: Re: [PATCHv2 bpf-next 1/5] bpf: Add socket assign support
Date: Wed, 25 Mar 2020 23:23:17 -0700	[thread overview]
Message-ID: <20200326062317.ofhr2o7azamwhaxf@kafai-mbp> (raw)
In-Reply-To: <20200325055745.10710-2-joe@wand.net.nz>

On Tue, Mar 24, 2020 at 10:57:41PM -0700, Joe Stringer wrote:
> Add support for TPROXY via a new bpf helper, bpf_sk_assign().
> 
> This helper requires the BPF program to discover the socket via a call
> to bpf_sk*_lookup_*(), then pass this socket to the new helper. The
> helper takes its own reference to the socket in addition to any existing
> reference that may or may not currently be obtained for the duration of
> BPF processing. For the destination socket to receive the traffic, the
> traffic must be routed towards that socket via local route. The
> simplest example route is below, but in practice you may want to route
> traffic more narrowly (eg by CIDR):
> 
>   $ ip route add local default dev lo
> 
> This patch avoids trying to introduce an extra bit into the skb->sk, as
> that would require more invasive changes to all code interacting with
> the socket to ensure that the bit is handled correctly, such as all
> error-handling cases along the path from the helper in BPF through to
> the orphan path in the input. Instead, we opt to use the destructor
> variable to switch on the prefetch of the socket.
> 
> Signed-off-by: Joe Stringer <joe@wand.net.nz>
> ---
> v2: Use skb->destructor to determine socket prefetch usage instead of
>       introducing a new metadata_dst
>     Restrict socket assign to same netns as TC device
>     Restrict assigning reuseport sockets
>     Adjust commit wording
> v1: Initial version
> ---
>  include/net/sock.h             |  7 +++++++
>  include/uapi/linux/bpf.h       | 25 ++++++++++++++++++++++++-
>  net/core/filter.c              | 31 +++++++++++++++++++++++++++++++
>  net/core/sock.c                |  9 +++++++++
>  net/ipv4/ip_input.c            |  3 ++-
>  net/ipv6/ip6_input.c           |  3 ++-
>  net/sched/act_bpf.c            |  2 ++
>  tools/include/uapi/linux/bpf.h | 25 ++++++++++++++++++++++++-
>  8 files changed, 101 insertions(+), 4 deletions(-)
> 

[ ... ]

> diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
> index 46f47e58b3be..6c7ed8fcc909 100644
> --- a/net/sched/act_bpf.c
> +++ b/net/sched/act_bpf.c
> @@ -53,6 +53,8 @@ static int tcf_bpf_act(struct sk_buff *skb, const struct tc_action *act,
>  		bpf_compute_data_pointers(skb);
>  		filter_res = BPF_PROG_RUN(filter, skb);
>  	}
> +	if (filter_res != TC_ACT_OK)
Should skb_sk_is_prefetched() be checked also?

> +		skb_orphan(skb);
>  	rcu_read_unlock();
>  
>  	/* A BPF program may overwrite the default action opcode.

  reply	other threads:[~2020-03-26  6:23 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25  5:57 [PATCHv2 bpf-next 0/5] Add bpf_sk_assign eBPF helper Joe Stringer
2020-03-25  5:57 ` [PATCHv2 bpf-next 1/5] bpf: Add socket assign support Joe Stringer
2020-03-26  6:23   ` Martin KaFai Lau [this message]
2020-03-26  6:31     ` Joe Stringer
2020-03-26 10:24   ` Lorenz Bauer
2020-03-26 22:52     ` Joe Stringer
2020-03-27  2:40       ` Joe Stringer
2020-03-25  5:57 ` [PATCHv2 bpf-next 2/5] bpf: Prefetch established socket destinations Joe Stringer
2020-03-26 21:11   ` Alexei Starovoitov
2020-03-26 21:45     ` Joe Stringer
2020-03-25  5:57 ` [PATCHv2 bpf-next 3/5] net: Track socket refcounts in skb_steal_sock() Joe Stringer
2020-03-25  5:57 ` [PATCHv2 bpf-next 4/5] bpf: Don't refcount LISTEN sockets in sk_assign() Joe Stringer
2020-03-25 10:29   ` Lorenz Bauer
2020-03-25 20:46     ` Joe Stringer
2020-03-26 10:20       ` Lorenz Bauer
2020-03-26 21:37         ` Joe Stringer
2020-03-25  5:57 ` [PATCHv2 bpf-next 5/5] selftests: bpf: add test for sk_assign Joe Stringer
2020-03-25 10:35   ` Lorenz Bauer
2020-03-25 20:55     ` Joe Stringer
2020-03-26  6:25       ` Martin KaFai Lau
2020-03-26  6:38         ` Joe Stringer
2020-03-26 23:39           ` Joe Stringer
2020-03-25 18:17   ` Yonghong Song
2020-03-25 21:20     ` Joe Stringer
2020-03-25 22:00       ` Yonghong Song
2020-03-25 23:07         ` Joe Stringer
2020-03-26 10:13     ` Lorenz Bauer
2020-03-26 21:07       ` call for bpf progs. " Alexei Starovoitov
2020-03-26 23:14         ` Yonghong Song
2020-03-27 10:02         ` Lorenz Bauer
2020-03-27 16:08           ` Alexei Starovoitov
2020-03-27 19:06         ` Joe Stringer
2020-03-27 20:16           ` Daniel Borkmann
2020-03-27 22:24             ` Alexei Starovoitov
2020-03-28  0:17           ` Andrii Nakryiko
2020-03-26  2:04   ` Andrii Nakryiko
2020-03-26  2:16   ` Andrii Nakryiko
2020-03-26  5:28     ` Joe Stringer
2020-03-26  6:31       ` Martin KaFai Lau
2020-03-26 19:36       ` Andrii Nakryiko
2020-03-26 21:38         ` Joe Stringer

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