xref: /freebsd/lib/libsys/setfib.2 (revision a970610a3af63b3f4df5b69d91c6b4093a00ed8f)
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25.Dd March 19, 2012
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
58with
59.Pp
60.Dl net.fibs= Ns Qq Em N
61.Pp
62where
63.Em N
64is an integer.
65This maximum is capped at 65536 due to the implementation storing
66the fib number in a 16-bit field in the
67.Xr mbuf 9
68packet header, however it is not suggested that one use such a large number
69as memory is allocated for every FIB regardless of whether it is used, and
70there are places where all FIBs are iterated over.
71.Pp
72The default FIB of the process will be applied to all protocol families
73that support multiple FIBs, and ignored by those that do not.
74The default FIB for a process may be overridden for a socket with the use
75of the
76.Dv SO_SETFIB
77socket option.
78.Sh RETURN VALUES
79.Rv -std setfib
80.Sh ERRORS
81The
82.Fn setfib
83system call
84will fail and no action will be taken and return
85.Er EINVAL
86if the
87.Fa fib
88argument is greater than the current system maximum.
89.Sh SEE ALSO
90.Xr setfib 1 ,
91.Xr setsockopt 2
92.Sh STANDARDS
93The
94.Fn setfib
95system call is a
96.Fx
97extension however similar extensions
98have been added to many other
99.Ux
100style kernels.
101.Sh HISTORY
102The
103.Fn setfib
104function appeared in
105.Fx 7.1 .
106