From: sdf@google.com
To: Andrey Ignatov <rdna@fb.com>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net,
ast@kernel.org, daniel@iogearbox.net
Subject: Re: [PATCH bpf-next 4/4] bpf: allow any port in bpf_bind helper
Date: Tue, 5 May 2020 10:09:12 -0700 [thread overview]
Message-ID: <20200505170912.GE241848@google.com> (raw)
In-Reply-To: <20200505160205.GC241848@google.com>
On 05/05, Stanislav Fomichev wrote:
> On 05/04, Andrey Ignatov wrote:
> > Stanislav Fomichev <sdf@google.com> [Mon, 2020-05-04 10:34 -0700]:
> > > [...]
> > > diff --git a/net/core/filter.c b/net/core/filter.c
> > > index fa9ddab5dd1f..fc5161b9ff6a 100644
> > > --- a/net/core/filter.c
> > > +++ b/net/core/filter.c
> > > @@ -4527,29 +4527,24 @@ BPF_CALL_3(bpf_bind, struct
> bpf_sock_addr_kern *, ctx, struct sockaddr *, addr,
> > > struct sock *sk = ctx->sk;
> > > int err;
> > >
> > > - /* Binding to port can be expensive so it's prohibited in the
> helper.
> > > - * Only binding to IP is supported.
> > > - */
> > > err = -EINVAL;
> > > if (addr_len < offsetofend(struct sockaddr, sa_family))
> > > return err;
> > > if (addr->sa_family == AF_INET) {
> > > if (addr_len < sizeof(struct sockaddr_in))
> > > return err;
> > > - if (((struct sockaddr_in *)addr)->sin_port != htons(0))
> > > - return err;
> > > return __inet_bind(sk, addr, addr_len,
> > > + BIND_FROM_BPF |
> > > BIND_FORCE_ADDRESS_NO_PORT);
> >
> > Should BIND_FORCE_ADDRESS_NO_PORT be passed only if port is zero?
> > Passing non zero port and BIND_FORCE_ADDRESS_NO_PORT at the same time
> > looks confusing (even though it works).
> Makes sense, will remove it here, thx.
Looking at it some more, I think we need to always have that
BIND_FORCE_ADDRESS_NO_PORT. Otherwise, it might regress your
usecase with zero port:
if (snum || !(inet->bind_address_no_port ||
(flags & BIND_FORCE_ADDRESS_NO_PORT)))
If snum == 0 we want to have either the flag on or
IP_BIND_ADDRESS_NO_PORT being set on the socket to prevent the port
allocation a bind time.
If snum != 0, BIND_FORCE_ADDRESS_NO_PORT doesn't matter and the port
is passed as an argument. We don't need to search for a free one, just
to confirm it's not used.
Am I missing something?
next prev parent reply other threads:[~2020-05-05 17:09 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-04 17:34 [PATCH bpf-next 0/4] bpf: allow any port in bpf_bind helper Stanislav Fomichev
2020-05-04 17:34 ` [PATCH bpf-next 1/4] selftests/bpf: generalize helpers to control backround listener Stanislav Fomichev
2020-05-05 6:23 ` Andrii Nakryiko
2020-05-05 16:08 ` sdf
2020-05-05 18:50 ` Andrii Nakryiko
2020-05-04 17:34 ` [PATCH bpf-next 2/4] selftests/bpf: adopt accept_timeout from sockmap_listen Stanislav Fomichev
2020-05-04 17:34 ` [PATCH bpf-next 3/4] net: refactor arguments of inet{,6}_bind Stanislav Fomichev
2020-05-05 18:16 ` Martin KaFai Lau
2020-05-05 18:19 ` Stanislav Fomichev
2020-05-04 17:34 ` [PATCH bpf-next 4/4] bpf: allow any port in bpf_bind helper Stanislav Fomichev
2020-05-04 23:22 ` Andrey Ignatov
2020-05-05 16:02 ` sdf
2020-05-05 17:09 ` sdf [this message]
2020-05-05 17:33 ` Andrey Ignatov
2020-05-05 17:43 ` sdf
2020-05-05 18:20 ` Andrey Ignatov
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