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From: Martin KaFai Lau <kafai@fb.com>
To: David Laight <David.Laight@aculab.com>
Cc: "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	David Miller <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	"kernel-team@fb.com" <kernel-team@fb.com>,
	Paolo Abeni <pabeni@redhat.com>
Subject: Re: [PATCH bpf-next 01/14] net: Change sock_setsockopt from taking sock ptr to sk ptr
Date: Wed, 27 Jul 2022 13:42:06 -0700	[thread overview]
Message-ID: <20220727204206.fhiamb66c3sljhg4@kafai-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <a9a3e00db4764ffcaf3324046d736b76@AcuMS.aculab.com>

On Wed, Jul 27, 2022 at 08:11:26AM +0000, David Laight wrote:
> From: Martin KaFai Lau
> > Sent: 27 July 2022 07:09
> > 
> > A latter patch refactors bpf_setsockopt(SOL_SOCKET) with the
> > sock_setsockopt() to avoid code duplication and code
> > drift between the two duplicates.
> > 
> > The current sock_setsockopt() takes sock ptr as the argument.
> > The very first thing of this function is to get back the sk ptr
> > by 'sk = sock->sk'.
> > 
> > bpf_setsockopt() could be called when the sk does not have
> > a userspace owner.  Meaning sk->sk_socket is NULL.  For example,
> > when a passive tcp connection has just been established.  Thus,
> > it cannot use the sock_setsockopt(sk->sk_socket) or else it will
> > pass a NULL sock ptr.
> 
> I'm intrigued, I've some code that uses sock_create_kern() to create
> sockets without a userspace owner - I'd have though bpf is doing
> much the same.
> 
> I end up doing:
>         if (level == SOL_SOCKET)
>                 err = sock_setsockopt(sock, level, optname, koptval, optlen);
>         else
>                 err = sock->ops->setsockopt(sock, level, optname, koptval,
>                                             optlen);
> to set options.
> (This code used to use kern_setsockopt() - but that got removed.)
> 
> I'd have though bpf would need similar code??
By no userspace owner, I was referring a sk has not been accept()-ed by
the userspace yet instead of a 'struct socket *sock' created for
the kernel internal use.  After another thought, that tcp_sock
is sort of owned by the listen sk,  I will rephrase the commit
message to avoid the confusion.

bpf prog does not have a 'sock' ptr because the sock
has not been created yet.

  reply	other threads:[~2022-07-27 20:42 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-27  6:08 [PATCH bpf-next 00/14] bpf: net: Remove duplicated codes from bpf_setsockopt() Martin KaFai Lau
2022-07-27  6:09 ` [PATCH bpf-next 01/14] net: Change sock_setsockopt from taking sock ptr to sk ptr Martin KaFai Lau
2022-07-27  8:11   ` David Laight
2022-07-27 20:42     ` Martin KaFai Lau [this message]
2022-07-27  8:16   ` Eric Dumazet
2022-07-27 18:50     ` Martin KaFai Lau
2022-07-27  6:09 ` [PATCH bpf-next 02/14] bpf: net: Avoid sock_setsockopt() taking sk lock when called from bpf Martin KaFai Lau
2022-07-27  8:36   ` David Laight
2022-07-27 20:05     ` Martin KaFai Lau
2022-07-27 16:47   ` sdf
2022-07-27 18:37     ` Martin KaFai Lau
2022-07-27 20:39       ` Stanislav Fomichev
2022-07-27 21:21         ` Martin KaFai Lau
2022-07-27 21:38           ` Stanislav Fomichev
2022-07-28  0:45             ` Martin KaFai Lau
2022-07-28  1:49               ` Jakub Kicinski
2022-07-28 16:31                 ` Martin KaFai Lau
2022-07-28 16:56                   ` Jakub Kicinski
2022-07-28 17:20                     ` Martin KaFai Lau
2022-07-28 17:40                       ` Jakub Kicinski
2022-07-29 10:04                     ` David Laight
2022-07-29 19:06                       ` Martin KaFai Lau
2022-07-27  6:09 ` [PATCH bpf-next 03/14] bpf: net: Consider optval.is_bpf before capable check in sock_setsockopt() Martin KaFai Lau
2022-07-27 16:54   ` sdf
2022-07-27 18:47     ` Martin KaFai Lau
2022-07-27  6:09 ` [PATCH bpf-next 04/14] bpf: net: Avoid do_tcp_setsockopt() taking sk lock when called from bpf Martin KaFai Lau
2022-07-27  6:09 ` [PATCH bpf-next 05/14] bpf: net: Avoid do_ip_setsockopt() " Martin KaFai Lau
2022-07-27  6:09 ` [PATCH bpf-next 06/14] bpf: net: Avoid do_ipv6_setsockopt() " Martin KaFai Lau
2022-07-27  6:09 ` [PATCH bpf-next 07/14] bpf: Embed kernel CONFIG check into the if statement in bpf_setsockopt Martin KaFai Lau
2022-07-27  6:09 ` [PATCH bpf-next 08/14] bpf: Change bpf_setsockopt(SOL_SOCKET) to reuse sock_setsockopt() Martin KaFai Lau
2022-07-27  6:09 ` [PATCH bpf-next 09/14] bpf: Refactor bpf specific tcp optnames to a new function Martin KaFai Lau
2022-07-27  6:09 ` [PATCH bpf-next 10/14] bpf: Change bpf_setsockopt(SOL_TCP) to reuse do_tcp_setsockopt() Martin KaFai Lau
2022-07-27  6:10 ` [PATCH bpf-next 11/14] bpf: Change bpf_setsockopt(SOL_IP) to reuse do_ip_setsockopt() Martin KaFai Lau
2022-07-27  6:10 ` [PATCH bpf-next 12/14] bpf: Change bpf_setsockopt(SOL_IPV6) to reuse do_ipv6_setsockopt() Martin KaFai Lau
2022-07-27  6:10 ` [PATCH bpf-next 13/14] bpf: Add a few optnames to bpf_setsockopt Martin KaFai Lau
2022-07-27  6:10 ` [PATCH bpf-next 14/14] selftests/bpf: bpf_setsockopt tests Martin KaFai Lau
2022-07-27 17:14 ` [PATCH bpf-next 00/14] bpf: net: Remove duplicated codes from bpf_setsockopt() Jakub Kicinski
2022-07-27 20:42   ` Martin KaFai Lau

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