| listen.2 (108028) | listen.2 (108087) |
|---|---|
| 1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 16 unchanged lines hidden (view full) --- 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" From: @(#)listen.2 8.2 (Berkeley) 12/11/93 | 1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. --- 16 unchanged lines hidden (view full) --- 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" From: @(#)listen.2 8.2 (Berkeley) 12/11/93 |
| 33.\" $FreeBSD: head/lib/libc/sys/listen.2 108028 2002-12-18 09:22:32Z ru $ | 33.\" $FreeBSD: head/lib/libc/sys/listen.2 108087 2002-12-19 09:40:28Z ru $ |
| 34.\" 35.Dd May 8, 2002 36.Dt LISTEN 2 37.Os 38.Sh NAME 39.Nm listen 40.Nd listen for connections on a socket 41.Sh LIBRARY --- 17 unchanged lines hidden (view full) --- 59.Fn listen 60system call applies only to sockets of type 61.Dv SOCK_STREAM 62or 63.Dv SOCK_SEQPACKET . 64.Pp 65The 66.Fa backlog | 34.\" 35.Dd May 8, 2002 36.Dt LISTEN 2 37.Os 38.Sh NAME 39.Nm listen 40.Nd listen for connections on a socket 41.Sh LIBRARY --- 17 unchanged lines hidden (view full) --- 59.Fn listen 60system call applies only to sockets of type 61.Dv SOCK_STREAM 62or 63.Dv SOCK_SEQPACKET . 64.Pp 65The 66.Fa backlog |
| 67parameter defines the maximum length the queue of | 67argument defines the maximum length the queue of |
| 68pending connections may grow to. 69If a connection 70request arrives with the queue full the client may 71receive an error with an indication of 72.Er ECONNREFUSED , 73or, in the case of TCP, the connection will be 74silently dropped. 75.Pp 76Note that before 77.Fx 4.5 78and the introduction of the syncache, 79the 80.Fa backlog | 68pending connections may grow to. 69If a connection 70request arrives with the queue full the client may 71receive an error with an indication of 72.Er ECONNREFUSED , 73or, in the case of TCP, the connection will be 74silently dropped. 75.Pp 76Note that before 77.Fx 4.5 78and the introduction of the syncache, 79the 80.Fa backlog |
| 81parameter also determined the length of the incomplete | 81argument also determined the length of the incomplete |
| 82connection queue, which held TCP sockets in the process 83of completing TCP's 3-way handshake. 84These incomplete connections 85are now held entirely in the syncache, which is unaffected by 86queue lengths. 87Inflated 88.Fa backlog 89values to help handle denial --- 21 unchanged lines hidden (view full) --- 111.Xr accept 2 Ns ed . 112If this secondary queue is full and a 113new connection comes in, the oldest socket which has not yet met 114its accept filter criteria will be terminated. 115.Pp 116This secondary queue, like the primary listen queue, is sized 117according to the 118.Fa backlog | 82connection queue, which held TCP sockets in the process 83of completing TCP's 3-way handshake. 84These incomplete connections 85are now held entirely in the syncache, which is unaffected by 86queue lengths. 87Inflated 88.Fa backlog 89values to help handle denial --- 21 unchanged lines hidden (view full) --- 111.Xr accept 2 Ns ed . 112If this secondary queue is full and a 113new connection comes in, the oldest socket which has not yet met 114its accept filter criteria will be terminated. 115.Pp 116This secondary queue, like the primary listen queue, is sized 117according to the 118.Fa backlog |
| 119parameter. | 119argument. |
| 120.Sh RETURN VALUES 121.Rv -std listen 122.Sh ERRORS 123The 124.Fn listen 125system call 126will fail if: 127.Bl -tag -width Er --- 30 unchanged lines hidden --- | 120.Sh RETURN VALUES 121.Rv -std listen 122.Sh ERRORS 123The 124.Fn listen 125system call 126will fail if: 127.Bl -tag -width Er --- 30 unchanged lines hidden --- |