MFC r225837:

MFC r225837:

 Pass the fibnum where we need filtering of the message on the
 rtsock allowing routing daemons to filter routing updates on an
 rtsock per FIB.

 Adjust raw_input() and split it into wrapper and a new function
 taking an optional callback argument even though we only have one
 consumer [1] to keep the hackish flags local to rtsock.c.

 PR:		kern/134931
 Submitted by:	multiple (see PR)
 Suggested by:	rwatson [1]
 Reviewed by:	rwatson

git-svn-id: svn://svn.freebsd.org/base/stable/8@225975 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f