xref: /freebsd-13.1/lib/libc/sys/setfib.2 (revision a9a393b3)
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25.\" $FreeBSD$
26.\"
27.Dd March 19, 2012
28.Dt SETFIB 2
29.Os
30.Sh NAME
31.Nm setfib
32.Nd set the default FIB (routing table) for the calling process
33.Sh LIBRARY
34.Lb libc
35.Sh SYNOPSIS
36.In sys/socket.h
37.Ft int
38.Fn setfib "int fib"
39.Sh DESCRIPTION
40The
41.Fn setfib
42system call sets the associated fib for all sockets opened
43subsequent to the call, to be that of the argument
44.Fa fib .
45The
46.Fa fib
47argument
48must be greater than or equal to 0
49and less than the current system maximum which
50may be retrieved by the
51.Va net.fibs
52sysctl.
53The system maximum is set in the kernel configuration file with
54.Bd -ragged -offset indent
55.Cd "options ROUTETABLES=" Ns Em N
56.Ed
57.Pp
58or in
59.Pa /boot/loader.conf
60with
61.Pp
62.Dl net.fibs= Ns Qq Em N
63.Pp
64where
65.Em N
66is an integer.
67This maximum is capped at 65536 due to the implementation storing
68the fib number in a 16-bit field in the
69.Xr mbuf 9
70packet header, however it is not suggested that one use such a large number
71as memory is allocated for every FIB regardless of whether it is used, and
72there are places where all FIBs are iterated over.
73.Pp
74The default fib of the process will be applied to all protocol families
75that support multiple fibs, and ignored by those that do not.
76The default fib for a process may be overridden for a socket with the use
77of the
78.Dv SO_SETFIB
79socket option.
80.Sh RETURN VALUES
81.Rv -std setfib
82.Sh ERRORS
83The
84.Fn setfib
85system call
86will fail and no action will be taken and return
87.Er EINVAL
88if the
89.Fa fib
90argument is greater than the current system maximum.
91.Sh SEE ALSO
92.Xr setfib 1 ,
93.Xr setsockopt 2
94.Sh STANDARDS
95The
96.Fn setfib
97system call is a
98.Fx
99extension however similar extensions
100have been added to many other
101.Ux
102style kernels.
103.Sh HISTORY
104The
105.Fn setfib
106function appeared in
107.Fx 7.1 .
108