diff options
| author | Chris Kuethe <ckuethe@cvs.openbsd.org> | 2008-05-02 06:49:33 +0000 |
|---|---|---|
| committer | Chris Kuethe <ckuethe@cvs.openbsd.org> | 2008-05-02 06:49:33 +0000 |
| commit | ac62022e3319b58cd03e552240772872ff219a70 (patch) | |
| tree | 11d64a9c749b3f2f1d31c20967ddf7faef658b0f /lib | |
| parent | 7f740532bb7e0e07efa3aea9fae9139a1f135642 (diff) | |
Make the SO_TIMESTAMP sockopt work. When set, this allows the user to
get a timestamp of when the datagram was accepted (by udp(4), for
example) rather than having to take a timestamp with gettimeofday(2)
when recv(2) returns - possibly several hundreds of microseconds later.
May be of use to those interested in precision network timing schemes
or QoS for media applications. Tested on alpha, amd64, i386 and sparc64.
manpage suggestions from jmc, ok deraadt
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/libc/sys/getsockopt.2 | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/lib/libc/sys/getsockopt.2 b/lib/libc/sys/getsockopt.2 index f92210225d4..85204ce56e3 100644 --- a/lib/libc/sys/getsockopt.2 +++ b/lib/libc/sys/getsockopt.2 @@ -1,4 +1,4 @@ -.\" $OpenBSD: getsockopt.2,v 1.22 2007/05/31 19:19:32 jmc Exp $ +.\" $OpenBSD: getsockopt.2,v 1.23 2008/05/02 06:49:31 ckuethe 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 31 2007 $ +.Dd $Mdocdate: May 2 2008 $ .Dt GETSOCKOPT 2 .Os .Sh NAME @@ -147,6 +147,7 @@ and set with .It Dv SO_RCVLOWAT Ta "set minimum count for input" .It Dv SO_SNDTIMEO Ta "set timeout value for output" .It Dv SO_RCVTIMEO Ta "set timeout value for input" +.It Dv SO_TIMESTAMP Ta "enables reception of a timestamp with datagrams" .It Dv SO_TYPE Ta "get the type of the socket (get only)" .It Dv SO_ERROR Ta "get and clear error on the socket (get only)" .El @@ -287,6 +288,23 @@ or with the error .Er EWOULDBLOCK if no data were received. .Pp +If the +.Dv SO_TIMESTAMP +option is enabled on a +.Dv SOCK_DGRAM +socket, the +.Xr recvmsg 2 +call will return a timestamp corresponding to when the datagram was +received. +The msg_control field in the msghdr structure points to a buffer +that contains a cmsghdr structure followed by a struct timeval. +The cmsghdr fields have the following values: +.Bd -literal -offset indent +cmsg_len = CMSG_LEN(sizeof(struct timeval)) +cmsg_level = SOL_SOCKET +cmsg_type = SCM_TIMESTAMP +.Ed +.Pp Finally, .Dv SO_TYPE and |