1.\" Copyright (c) 2008 Cisco Systems. All rights reserved. 2.\" Author: Julian Elischer 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. 9.\" 2. Neither the name of the Cisco Systems nor the names of its employees 10.\" may be used to endorse or promote products derived from this software 11.\" without specific prior written permission. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.Dd January 10, 2025 26.Dt SETFIB 2 27.Os 28.Sh NAME 29.Nm setfib 30.Nd set the default FIB (routing table) for the calling process 31.Sh LIBRARY 32.Lb libc 33.Sh SYNOPSIS 34.In sys/socket.h 35.Ft int 36.Fn setfib "int fib" 37.Sh DESCRIPTION 38The 39.Fn setfib 40system call sets the associated FIB (routing table) for all sockets opened 41subsequent to the call, to be that of the argument 42.Fa fib . 43The 44.Fa fib 45argument 46must be greater than or equal to 0 47and less than the current system maximum which 48may be retrieved by the 49.Va net.fibs 50sysctl. 51The system maximum is set in the kernel configuration file with 52.Bd -ragged -offset indent 53.Cd "options ROUTETABLES=" Ns Em N 54.Ed 55.Pp 56or in 57.Pa /boot/loader.conf 58or 59.Pa /etc/sysctl.conf 60with 61.Pp 62.Dl net.fibs= Ns Qq Em N 63.Pp 64where 65.Em N 66is an integer smaller than 65536. 67Note that the number of FIBs may be increased after booting, but cannot be 68reduced. 69.Pp 70The maximum of 65536 is due to the implementation storing 71the FIB number in a 16-bit field in the 72.Xr mbuf 9 73packet header, however it is not suggested that one use such a large number 74as memory is allocated for every FIB regardless of whether it is used, and 75there are places where all FIBs are iterated over. 76.Pp 77The default FIB of the process will be applied to all protocol families 78that support multiple FIBs, and ignored by those that do not. 79The default FIB for a process may be overridden for a socket with the use 80of the 81.Dv SO_SETFIB 82socket option. 83.Sh RETURN VALUES 84.Rv -std setfib 85.Sh ERRORS 86The 87.Fn setfib 88system call 89will fail and no action will be taken and return 90.Er EINVAL 91if the 92.Fa fib 93argument is greater than the current system maximum. 94.Sh SEE ALSO 95.Xr setfib 1 , 96.Xr setsockopt 2 97.Sh STANDARDS 98The 99.Fn setfib 100system call is a 101.Fx 102extension however similar extensions 103have been added to many other 104.Ux 105style kernels. 106.Sh HISTORY 107The 108.Fn setfib 109function appeared in 110.Fx 7.1 . 111