Re: [PATCH] ipv4: Add option to get TCP_FASTOPEN to getsockopt()
From: Neal Cardwell <ncardwell@google.com>
Date: 2014-04-15 00:43:29
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On Mon, Apr 14, 2014 at 1:39 PM, Kenjiro Nakayama [off-list ref] wrote:
quoted hunk
TCP_FASTOPEN option can be set via setsockopt(), but the value cannot be gotten via getsockopt(). This patch adds the option to getsockopt(). Sighned-off-by: Kenjiro Nakayama [off-list ref] Add option to get TCP_FASTOPEN to getsockopt() --- net/ipv4/tcp.c | 5 +++++ 1 file changed, 5 insertions(+)diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 4bd6d52..6ccdbcc 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c@@ -2916,6 +2916,11 @@ static int do_tcp_getsockopt(struct sock *sk, int level, case TCP_USER_TIMEOUT: val = jiffies_to_msecs(icsk->icsk_user_timeout); break; + + case TCP_FASTOPEN: + val = sysctl_tcp_fastopen; + break; + case TCP_TIMESTAMP: val = tcp_time_stamp + tp->tsoffset; break; --1.9.0
Hi, Please cc the Linux network development mailing list at netdev@vger.kernel.org (cc-ed) for Linux networking patches like this. I don't think this is the implementation we'd want for a getsockopt() for TCP_FASTOPEN. I imagine that since the setsockopt(TCP_FASTOPEN) enables Fast Open on a listening socket with a given backlog, if we add a corresponding getsockopt() then it should return that Fast Open backlog if Fast Open is enabled on the listening socket, or 0 otherwise. That is, basically it would be querying whether fastopen_init_queue() has been run and returning fastopenq->max_qlen if so. That way setsockopt(TCP_FASTOPEN, getsockopt(TCP_FASTOPEN)) will be a NOP in most cases, as one would expect. neal