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From: Paolo Abeni <>
To: Paul Moore <>, Florian Westphal <>
Cc: Stephen Smalley <>,,,
Subject: Re: [MPTCP] Re: [RFC PATCH] selinux: handle MPTCP consistently with TCP
Date: Fri, 04 Dec 2020 11:04:36 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Thu, 2020-12-03 at 21:24 -0500, Paul Moore wrote:
> On Thu, Dec 3, 2020 at 6:54 PM Florian Westphal <> wrote:
> > Paul Moore <> wrote:
> > > I'm not very well versed in MPTCP, but this *seems* okay to me, minus
> > > the else-crud chunk.  Just to confirm my understanding, while MPTCP
> > > allows one TCP connection/stream to be subdivided and distributed
> > > across multiple interfaces, it does not allow multiple TCP streams to
> > > be multiplexed on a single connection, yes?
> > 
> > Its the latter.  The application sees a TCP interface (socket), but
> > data may be carried over multiple individual tcp streams on the wire.
> Hmm, that may complicate things a bit from a SELinux perspective.  Maybe not.
> Just to make sure I understand, with MPTCP, a client that
> traditionally opened multiple TCP sockets to talk to a server would
> now just open a single MPTCP socket and create multiple sub-flows
> instead of multiple TCP sockets?

I expect most clients will not be updated specifically for MPTCP,
except changing the protocol number at socket creation time - and we
would like to avoid even that.

If a given application creates multiple sockets, it will still do that
with MPTCP. The kernel, according to the configuration provided by the
user-space and/or by the peer, may try to create additional subflows
for each MPTCP sockets, using different local or remote address and/or
port number. Each subflow is represented inside the kernel as a TCP
'struct sock' with specific ULP operations. No related 'struct socket'
is exposed to user-space.



  reply	other threads:[~2020-12-04 10:06 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
     [not found] ` <>
     [not found]   ` <>
2020-12-03 23:30     ` [MPTCP] Re: [RFC PATCH] selinux: handle MPTCP consistently with TCP Paul Moore
2020-12-03 23:54       ` Florian Westphal
2020-12-04  2:24         ` Paul Moore
2020-12-04 10:04           ` Paolo Abeni [this message]
2020-12-04 23:22             ` Paul Moore
2020-12-08 15:35               ` Paolo Abeni
2020-12-08 23:35                 ` Paul Moore
2020-12-09 10:02                   ` Paolo Abeni
2020-12-10  2:43                     ` Paul Moore

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