2 .\" Copyright (c) 2000 Alfred Perlstein
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26 .\" $FreeBSD: src/share/man/man9/accf_http.9,v 1.1.2.6 2002/07/02 01:03:59 brian Exp $
27 .\" $DragonFly: src/share/man/man9/accf_http.9,v 1.3 2006/07/22 23:52:23 swildner Exp $
34 .Nd "buffer incoming connections until a certain complete HTTP requests arrive"
37 .Cd options ACCEPT_FILTER_HTTP
40 This is a filter to be placed on a socket that will be using
42 to receive incoming HTTP connections.
44 It prevents the application from receiving the connected descriptor via
46 until either a full HTTP/1.0 or HTTP/1.1 HEAD or GET request has
47 been buffered by the kernel.
49 If something other than a HTTP/1.0 or
50 HTTP/1.1 HEAD or GET request is received the kernel will
51 allow the application to receive the connection descriptor
57 is such that a server will not have to context switch several times
58 before performing the initial parsing of the request.
59 This effectively reduces the amount of required CPU utilization
60 to handle incoming requests by keeping active
61 processes in preforking servers such as Apache low
62 and reducing the size of the filedescriptor set that needs
63 to be managed by interfaces such as
72 kernel option is also a module that can be enabled at runtime via
74 if the INET option has been compiled into the kernel.
76 Assuming ACCEPT_FILTER_HTTP has been included in the kernel config
79 has been loaded, this will enable the http accept filter
82 .Bd -literal -offset 0i
83 struct accept_filter_arg afa;
85 bzero(&afa, sizeof(afa));
86 strcpy(afa.af_name, "httpready");
87 setsockopt(sok, SOL_SOCKET, SO_ACCEPTFILTER, &afa, sizeof(afa));
93 The accept filter mechanism and the
94 accf_http filter were introduced in
97 This manual page and the filter were written by
98 .An Alfred Perlstein .