Implement an idle timeout for the socket splicing. A new `sp_idle'

field of the `splice' structure can be used to specify a period of
inactivity after which splicing will be dissolved.  ETIMEDOUT error
retrieved with a SO_ERROR indicates the idle timeout expiration.
With comments from and OK bluhm.

2 files changed, 31 insertions, 10 deletions

diff --git a/lib/libc/sys/getsockopt.2 b/lib/libc/sys/getsockopt.2
index ecf38e1e6bd..9de91b68e69 100644
--- a/lib/libc/sys/getsockopt.2
+++ b/lib/libc/sys/getsockopt.2
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: getsockopt.2,v 1.32 2011/05/02 20:18:17 jmc Exp $
+.\"	$OpenBSD: getsockopt.2,v 1.33 2011/07/04 00:34:43 mikeb Exp $
 .\"	$NetBSD: getsockopt.2,v 1.7 1995/02/27 12:33:29 cgd Exp $
 .\"
 .\" Copyright (c) 1983, 1991, 1993
@@ -30,7 +30,7 @@
 .\"
 .\"     @(#)getsockopt.2	8.3 (Berkeley) 4/19/94
 .\"
-.Dd $Mdocdate: May 2 2011 $
+.Dd $Mdocdate: July 4 2011 $
 .Dt GETSOCKOPT 2
 .Os
 .Sh NAME
@@ -362,15 +362,19 @@ In the second form,
 is a
 .Vt struct splice
 with the drain socket in
-.Va sp_fd
-and a positive maximum number of bytes or 0 in
-.Va sp_max .
+.Va sp_fd ,
+a positive maximum number of bytes or 0 in
+.Va sp_max
+and an idle timeout
+.Va sp_idle
+in a form of a
+.Vt struct timeval .
 If \-1 is given as drain socket, the source socket
 .Fa s
 gets unspliced.
 Otherwise the spliced data transfer continues within the kernel
 until the optional maximum is reached, one of the connections
-terminates or an error occurs.
+terminates, idle timeout expires or an error occurs.
 A successful
 .Xr select 2 ,
 .Xr poll 2 ,
@@ -383,6 +387,11 @@ is available.
 The error status can be examined with
 .Dv SO_ERROR
 at the source socket.
+.Er ETIMEDOUT
+error is set if there was no data transfered between two sockets
+during the
+.Va sp_idle
+period of time.
 Note that if a maximum is given, it is only guaranteed that no more
 bytes are transferred.
 A short splice can happen but then a second call to splice will
diff --git a/share/man/man9/sosplice.9 b/share/man/man9/sosplice.9
index 7f865f479fd..c916b2bdaa5 100644
--- a/share/man/man9/sosplice.9
+++ b/share/man/man9/sosplice.9
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: sosplice.9,v 1.2 2011/03/12 18:31:41 bluhm Exp $
+.\"	$OpenBSD: sosplice.9,v 1.3 2011/07/04 00:34:43 mikeb Exp $
 .\"
 .\" Copyright (c) 2011 Alexander Bluhm <bluhm@openbsd.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: March 12 2011 $
+.Dd $Mdocdate: July 4 2011 $
 .Dt SOSPLICE 9
 .Os
 .Sh NAME
@@ -23,7 +23,7 @@
 .Nd splice two sockets for zero-copy data transfer
 .Sh SYNOPSIS
 .Ft int
-.Fn sosplice "struct socket *so" "int fd" "off_t max"
+.Fn sosplice "struct socket *so" "int fd" "off_t max" "struct timeval *tv"
 .Ft int
 .Fn somove "struct socket *so" "int wait"
 .Sh DESCRIPTION
@@ -41,6 +41,12 @@ is negative, an existing splicing gets dissolved.
 If
 .Fa max
 is positive, at most that many bytes will get transferred.
+If
+.Fa tv
+is not NULL, a
+.Xr timeout 9
+is scheduled to dissolve splicing in the case when no data can be
+transferred for the specified period of time.
 Socket splicing can be invoked from user-land via the
 .Xr setsockopt 2
 system-call at the
@@ -138,6 +144,11 @@ If that fails and the drain socket cannot send anymore, an
 .Er EPIPE
 error is set on the source socket.
 .Pp
+If the idle timeout was specified and no data was transferred
+for that period of time, splicing gets dissolved and an
+.Er ETIMEDOUT
+error is set on the source socket.
+.Pp
 Finally the socket splicing gets dissolved if the source socket
 cannot receive anymore and its receive buffer is empty; or if the
 drain socket cannot send anymore; or if the maximum has been reached;
@@ -200,7 +211,8 @@ locked.
 .El
 .Sh SEE ALSO
 .Xr setsockopt 2 ,
-.Xr options 4
+.Xr options 4 ,
+.Xr timeout 9
 .Sh HISTORY
 Socket splicing first appeared in
 .Ox 4.9 .