Copyright (c) 2015 The NetBSD Foundation, Inc.
All rights reserved.
This code is derived from software contributed to The NetBSD Foundation
by Christos Zoulas.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
.Dd January 22, 2015 .Dt LIBBLACKLIST 3 .Os .Sh NAME .Nm blacklist_open , .Nm blacklist_close , .Nm blacklist_r , .Nm blacklist , .Nm blacklist_sa .Nm blacklist_sa_r , .Nd Blacklistd notification library .Sh LIBRARY .Lb libblacklist .Sh SYNOPSIS n blacklist.h .Ft struct blacklist * .Fn blacklist_open "void" .Ft void .Fn blacklist_close "struct blacklist *cookie" .Ft int .Fn blacklist "int action" "int fd" "const char *msg" .Ft int .Fn blacklist_r "struct blacklist *cookie" "int action" "int fd" "const char *msg" .Ft int .Fn blacklist_sa "int action" "int fd" "const struct sockaddr *sa" "socklen_t salen" "const char *msg" .Ft int .Fn blacklist_sa_r "struct blacklist *cookie" "int action" "int fd" "const struct sockaddr *sa" "socklen_t salen" "const char *msg" .Sh DESCRIPTION These functions can be used by daemons to notify .Xr blacklistd 8 about successful and failed remote connections so that blacklistd can block or release port access to prevent Denial of Service attacks.
p The function .Fn blacklist_open creates a the necessary state to communicate with .Xr blacklistd 8 and returns a pointer to it, or .Dv NULL on failure.
p The .Fn blacklist_close function frees all memory and resources used.
p The .Fn blacklist function sends a message to .Xr blacklistd 8 , with an .Ar action argument specifying .Dv 1 for a failed connection or .Dv 0 for a successful connection, a file descriptor .Ar fd specifying the accepted file descriptor connected to the client, and an optional message in the .Ar msg argument.
p The .Fn blacklist_r function is more efficient because it keeps the blacklist state around.
p The .Fn blacklist_sa and .Fn blacklist_sa_r functions can be used with unconnected sockets, where .Xr getpeername 2 will not work, the server will pass the peer name in the message.
p All functions log errors to .Xr syslogd 8 . .Sh RETURN VALUES The function .Fn bl_open returns a cookie on success and .Dv NULL on failure setting errno to an appropriate value.
p The .Fn bl_send function returns .Dv 0 on success and .Dv -1 on failure setting errno to an appropriate value. .Sh SEE ALSO .Xr blacklistd.conf 5 , .Xr blacklistd 8 .Sh AUTHORS .An Christos Zoulas