From: Florian Westphal <fw@strlen.de>
To: Paolo Abeni <pabeni@redhat.com>
Cc: Florian Westphal <fw@strlen.de>, mptcp@lists.linux.dev
Subject: Re: [PATCH mptcp-next] mptcp: ignore unsupported msg flags
Date: Thu, 15 Apr 2021 10:27:00 +0200 [thread overview]
Message-ID: <20210415082700.GH14932@breakpoint.cc> (raw)
In-Reply-To: <d75da6f043ccb23b6dc0ef422cd25614427593ac.camel@redhat.com>
Paolo Abeni <pabeni@redhat.com> wrote:
> The intent of this patch is ignoring the unsupported flags. For sendmsg
> that is all of them except MSG_MORE, MSG_DONTWAIT, MSG_NOSIGNAL:
>
> MSG_OOB
> MSG_PEEK
> MSG_DONTROUTE
> MSG_TRYHARD
> MSG_CTRUNC
> MSG_PROBE
> MSG_TRUNC
> MSG_EOR
> MSG_FIN
> MSG_SYN
> MSG_CONFIRM
> MSG_RST
> MSG_ERRQUEUE
> MSG_WAITFORONE
> MSG_SENDPAGE_NOPOLICY
> MSG_SENDPAGE_NOTLAST
> MSG_BATCH
> MSG_EOF
> MSG_NO_SHARED_FRAGS
> MSG_SENDPAGE_DECRYPTED
> MSG_ZEROCOPY
> MSG_FASTOPEN
> MSG_CMSG_CLOEXEC
Looks like TCP ignores all of them except fastopen:
sendto(5, "foo\n", 4, 0, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_OOB, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_PEEK, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_DONTROUTE, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_CTRUNC, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_PROBE, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_TRUNC, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_DONTWAIT, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_EOR, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_WAITALL, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_FIN, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_SYN, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_CONFIRM, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_RST, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_ERRQUEUE, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_NOSIGNAL, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_MORE, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_WAITFORONE, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_SENDPAGE_NOTLAST, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_BATCH, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_NO_SHARED_FRAGS, NULL, 0) = 4
sendto(5, "foo\n", 4, 0x100000 /* MSG_??? */, NULL, 0) = 4
sendto(5, "foo\n", 4, 0x200000 /* MSG_??? */, NULL, 0) = 4
sendto(5, "foo\n", 4, 0x400000 /* MSG_??? */, NULL, 0) = 4
sendto(5, "foo\n", 4, 0x800000 /* MSG_??? */, NULL, 0) = 4
sendto(5, "foo\n", 4, 0x1000000 /* MSG_??? */, NULL, 0) = 4
sendto(5, "foo\n", 4, 0x2000000 /* MSG_??? */, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_ZEROCOPY, NULL, 0) = 4
sendto(5, "foo\n", 4, 0x8000000 /* MSG_??? */, NULL, 0) = 4
sendto(5, "foo\n", 4, 0x10000000 /* MSG_??? */, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_FASTOPEN, NULL, 0) = -1 EISCONN (Transport
endpoint is already connected)
sendto(5, "foo\n", 4, MSG_CMSG_CLOEXEC, NULL, 0) = 4
sendto(5, "foo\n", 4, MSG_CMSG_COMPAT, NULL, 0) = 4
(fd 4 is a established tcp socket, after successful connect()).
> should we define a 'bail on use' mask with a subset of the above? The
> candidates I see are:
> MSG_TRUNC
> MSG_PEEK
> MSG_OOB
Looks like we only need to handle FASTOPEN.
next prev parent reply other threads:[~2021-04-15 8:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 15:23 [PATCH mptcp-next] mptcp: ignore unsupported msg flags Paolo Abeni
2021-04-14 15:51 ` Florian Westphal
2021-04-14 16:07 ` Paolo Abeni
2021-04-15 8:27 ` Florian Westphal [this message]
2021-04-15 9:33 ` Paolo Abeni
2021-04-15 9:44 ` Florian Westphal
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