setfib(2) set the default FIB (routing table) for the calling process.


Lb libc


In sys/socket.h Ft int Fn setfib int fib


The Fn setfib system call sets the associated fib for all sockets opened subsequent to the call, to be that of the argument Fa fib . The Fa fib argument must be greater than or equal to 0 and less than the current system maximum which may be retrieved by the net.fibs sysctl. The system maximum is set in the kernel configuration file with

or in /boot/loader.conf with

net.fibs= Qq N

where N is an integer. This maximum is capped at 65536 due to the implementation storing the fib number in a 16-bit field in the mbuf(9) packet header, however it is not suggested that one use such a large number as memory is allocated for every FIB regardless of whether it is used, and there are places where all FIBs are iterated over.

The default fib of the process will be applied to all protocol families that support multiple fibs, and ignored by those that do not. The default fib for a process may be overridden for a socket with the use of the SO_SETFIB socket option.


Rv -std setfib


The Fn setfib system call will fail and no action will be taken and return Er EINVAL if the Fa fib argument is greater than the current system maximum.


The Fn setfib system call is a Fx extension however similar extensions have been added to many other UNIX style kernels.


The Fn setfib function appeared in Fx 7.1 .