cvs commit: src/sys/kern uipc_socket.c

[Maxim Konovalov]

On Thu, 15 Sep 2005, 13:16+0100, Robert Watson wrote:

>
> On Thu, 15 Sep 2005, Maxim Konovalov wrote:
>
> > maxim       2005-09-15 11:45:37 UTC
> >
> >  FreeBSD src repository
> >
> >  Modified files:
> >    sys/kern             uipc_socket.c
> >  Log:
> >  o Return ENOTCONN when shutdown(2) on non-connected socket.
> >
> >  PR:             kern/84761
> >  Submitted by:   James Juran
> >  R-test:         tools/regression/sockets/shutdown
> >  MFC after:      1 month
>
> Are you sure this is the right thing to do?  I've seen shutdown used
> in several applications on non-connection-oriented sockets in order
> to indicate no messages will be received, so not to allow received
> packets to consume space.  Typical use is in the context of a raw IP
> or IPv6 socket, where raw packets will be sent but never received,
> and the socket will otherwise collect the normal random network
> detrious.
>
> For example, rtsold(8) uses shutdown(2) on its IPv6 raw socket to
> indicate it is send-only, so received packets should not be stored
> in the socket buffer since they will never be read.  It does,
> however, contain the not unusual bug that it is called with an
> argument of 0, assuming that that will be the value SHUT_RD.  I'm
> fairly sure we used to have other examples of shutdown(2) being used
> in this way in the tree but don't see any others in a casual glance.
>
> While POSIX mentions behavior for full-duplex connections, it does
> not specify for sockets that are not connection-oriented, so as I
> read it, the behavior we provide is permitted.

Linux 2.4.21 return ENOTSUP for SOCK_RAW and ENOTCONN for
non-connected SOCK_DGRAM.  Solaris 9 returns ENOTCONN for
non-connected SOCK_RAW and they don't allow shutdown(2) on
non-connected sockets.  Anyhow, I'll backout this code.

-- 
Maxim Konovalov