From: Jakub Sitnicki <jakub@cloudflare.com>
To: Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Lorenz Bauer <lmb@cloudflare.com>,
kernel-team@cloudflare.com, netdev@vger.kernel.org,
bpf@vger.kernel.org
Subject: Re: [PATCH 0/5] Return fds from privileged sockhash/sockmap lookup
Date: Wed, 11 Mar 2020 14:44:32 +0100 [thread overview]
Message-ID: <87y2s7xayn.fsf@cloudflare.com> (raw)
In-Reply-To: <20200310174711.7490-1-lmb@cloudflare.com>
On Tue, Mar 10, 2020 at 06:47 PM CET, Lorenz Bauer wrote:
> We want to use sockhash and sockmap to build the control plane for
> our upcoming BPF socket dispatch work. We realised that it's
> difficult to resize or otherwise rebuild these maps if needed,
> because there is no way to get at their contents. This patch set
> allows a privileged user to retrieve fds from these map types,
> which removes this obstacle.
Since it takes just a few lines of code to get an FD for a sock:
fd = get_unused_fd_flags(O_CLOEXEC);
if (unlikely(fd < 0))
return fd;
fd_install(fd, get_file(sk->sk_socket->file));
... I can't help but wonder where's the catch?
IOW, why wasn't this needed so far?
How does Cilium avoid resizing & rebuilding sockmaps?
Just asking out of curiosity.
[...]
next prev parent reply other threads:[~2020-03-11 13:44 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-10 17:47 [PATCH 0/5] Return fds from privileged sockhash/sockmap lookup Lorenz Bauer
2020-03-10 17:47 ` [PATCH 1/5] bpf: add map_copy_value hook Lorenz Bauer
2020-03-10 17:47 ` [PATCH 2/5] bpf: convert queue and stack map to map_copy_value Lorenz Bauer
2020-03-11 14:00 ` Jakub Sitnicki
2020-03-11 22:31 ` John Fastabend
2020-03-10 17:47 ` [PATCH 3/5] bpf: convert sock map and hash " Lorenz Bauer
2020-03-11 13:55 ` Jakub Sitnicki
2020-03-10 17:47 ` [PATCH 4/5] bpf: sockmap, sockhash: return file descriptors from privileged lookup Lorenz Bauer
2020-03-11 23:27 ` John Fastabend
2020-03-17 10:17 ` Lorenz Bauer
2020-03-17 15:18 ` Jakub Sitnicki
2020-03-17 18:16 ` John Fastabend
2020-03-10 17:47 ` [PATCH 5/5] bpf: sockmap, sockhash: test looking up fds Lorenz Bauer
2020-03-11 13:52 ` Jakub Sitnicki
2020-03-11 17:24 ` Lorenz Bauer
2020-03-11 13:44 ` Jakub Sitnicki [this message]
2020-03-11 22:40 ` [PATCH 0/5] Return fds from privileged sockhash/sockmap lookup John Fastabend
2020-03-12 1:58 ` Alexei Starovoitov
2020-03-12 9:16 ` Lorenz Bauer
2020-03-12 17:58 ` Alexei Starovoitov
2020-03-12 19:32 ` John Fastabend
2020-03-13 11:03 ` Lorenz Bauer
2020-03-13 10:48 ` Lorenz Bauer
2020-03-14 2:58 ` Alexei Starovoitov
2020-03-17 9:55 ` Lorenz Bauer
2020-03-17 19:05 ` John Fastabend
2020-03-20 15:12 ` Lorenz Bauer
2020-04-07 3:08 ` Alexei Starovoitov
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