diff mbox

[v2] ipv4: Add option to get TCP_FASTOPEN to getsockopt()

Message ID 87r44yixds.fsf@gmail.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Kenjiro Nakayama April 15, 2014, 12:35 p.m. UTC
Hi,

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 <nakayamakenjiro@gmail.com>

 	Add option to get TCP_FASTOPEN to getsockopt()
---
 net/ipv4/tcp.c | 7 +++++++
 1 file changed, 7 insertions(+)

--
1.9.0
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Comments

Eric Dumazet April 15, 2014, 1:52 p.m. UTC | #1
On Tue, 2014-04-15 at 21:35 +0900, Kenjiro Nakayama wrote:
> Hi,
> 
> 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 <nakayamakenjiro@gmail.com>
> 
>  	Add option to get TCP_FASTOPEN to getsockopt()
> ---
>  net/ipv4/tcp.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 4bd6d52..86186f4 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -2916,6 +2916,13 @@ 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 = icsk->icsk_accept_queue.fastopenq ?
> +		    icsk->icsk_accept_queue.fastopenq->max_qlen
> +		    : sysctl_tcp_fastopen;
> +		break;
> +
>  	case TCP_TIMESTAMP:
>  		val = tcp_time_stamp + tp->tsoffset;
>  		break;
> --
> 1.9.0

I have no idea why you keep using sysctl_tcp_fastopen in your patches.

It seems you only want your application to
read /proc/sys/net/ipv4/tcp_fastopen ?

And you don't have CONFIG_PROC_FS maybe, and you add a workaround ?

As already mentioned, even if sysctl_tcp_fastopen is set to one, it does
not mean this socket is fastopen enabled.

setsockopt()/getsockopt() for a given key should be symmetrical.

ie :

getsockopt(fd, SOL_TCP, TCP_FASTOPEN, &val, &len);
setsockopt(fd, SOL_TCP, TCP_FASTOPEN, &val, sizeof(val));

should be a no operation. Its obviously not the case with your proposal.

Please address Neal concerns, and add in the changelog what is this
option supposed to do _exactly_.

hint : max_qlen and sysctl_tcp_fastopen do not have the same units,
its like comparing apples and oranges.

Thanks



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Neal Cardwell April 15, 2014, 1:57 p.m. UTC | #2
On Tue, Apr 15, 2014 at 8:35 AM, Kenjiro Nakayama
<nakayamakenjiro@gmail.com> wrote:
> Hi,

Please omit the "Hi," at the top of the patch description, so the top
of the email can be used directly as a git commit description.

> 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 <nakayamakenjiro@gmail.com>

Typo: this should be "Signed-off-by:"

>         Add option to get TCP_FASTOPEN to getsockopt()

Likewise, please omit the extra descriptive text below the
"Signed-off-by:" footer.

(And, of course, please note Eric's remarks as well...)

thanks,
neal
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diff mbox

Patch

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 4bd6d52..86186f4 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2916,6 +2916,13 @@  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 = icsk->icsk_accept_queue.fastopenq ?
+		    icsk->icsk_accept_queue.fastopenq->max_qlen
+		    : sysctl_tcp_fastopen;
+		break;
+
 	case TCP_TIMESTAMP:
 		val = tcp_time_stamp + tp->tsoffset;
 		break;