.\" $OpenBSD: rtalloc.9,v 1.3 2014/12/05 16:55:53 schwarze Exp $
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.\" Copyright (c) 2014 Martin Pieuchot
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.Dd $Mdocdate: December 5 2014 $
.Dt RTALLOC 9
.Os
.Sh NAME
.Nm rtalloc ,
.Nm rtalloc_mpath ,
.Nm rtfree
.Nd routing entry interface
.Sh SYNOPSIS
.In sys/types.h
.In sys/socket.h
.In net/route.h
.Ft struct rtentry *
.Fn rtalloc "struct sockaddr *dst" "int flags" "unsigned int rtableid"
.Ft struct rtentry *
.Fn rtalloc_mpath "struct sockaddr *dst" "uint32_t *src" "unsigned int rtableid"
.Ft void
.Fn rtfree "struct rtentry *rt"
.Sh DESCRIPTION
The
.Fn rtalloc
function looks in the routing table
.Fa rtableid
for an entry matching
.Fa dst .
The following
.Fa flags
can be specified:
.Bl -tag -width RT_RESOLVE -offset indent
.It Dv RT_REPORT
Notify the routing sockets if the lookup fails.
.It Dv RT_RESOLVE
Allocate and return a cloned entry for
.Fa dst
if it does not exist and the lookup returned a cloning entry.
.El
.Pp
The
.Fn rtalloc_mpath
function does the same as
.Fn rtalloc
with the
.Dv RT_REPORT
and
.Dv RT_RESOLVE
.Fa flags ,
but selects a multipath routing entry corresponding to
.Fa src
when possible.
.Pp
The
.Fn rtfree
function releases a reference to the routing entry
.Fa rt ,
freeing it if the reference count drops to 0.
.Sh CONTEXT
.Fn rtalloc ,
.Fn rtalloc_mpath ,
and
.Fn rtfree
can be called during autoconf, from process context, or from interrupt context.
.Sh SEE ALSO
.Xr route 4 ,
.Xr rtrequest1 9