.\"     $OpenBSD: route.9,v 1.16 2015/11/23 17:53:57 jmc Exp $
.\"
.\" Copyright (c) 2011 Bret S. Lambert <blambert@openbsd.org>
.\" All rights reserved.
.\"
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.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
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.Dd $Mdocdate: November 23 2015 $
.Dt RT_LOOKUP 9
.Os
.Sh NAME
.Nm rt_lookup ,
.Nm rt_setgate ,
.Nm rtredirect ,
.Nm rtdeletemsg
.Nd kernel routing interface
.Sh SYNOPSIS
.In net/route.h
.Ft struct rtentry *
.Fn rt_lookup "struct sockaddr *dst" "struct sockaddr *mask" "u_int tableid"
.Ft int
.Fn rt_setgate "struct rtentry *rt0" "struct sockaddr *dst" \
"struct sockaddr *gate" "u_int tableid"
.Ft void
.Fn rtredirect "struct sockaddr *dst" "struct sockaddr *gateway" \
"struct sockaddr *netmask" "int flags" "struct sockaddr *src" \
"struct rtentry **rtp" "u_int rdomain"
.Ft int
.Fn rtdeletemsg "struct rtentry *rt" "u_int tableid"
.Sh DESCRIPTION
Routing entries describe the routes to be taken by packets in a router.
.Bl -tag -width Ds
.It Fn rt_lookup "struct sockaddr *dst" "struct sockaddr *mask" "u_int tableid"
Return pointer to routing entry corresponding to address
.Fa dst
with a mask of
.Fa mask
from table
.Fa tableid .
.It Fn rt_setgate "struct rtentry *rt0" "struct sockaddr *dst" \
"struct sockaddr *gate" "u_int tableid"
Set the address of the gateway for routes described by
.Fa rt0
to
.Fa gateway .
If memory must be allocated to hold the gateway address,
the address for which
.Fa rt0
describes routes will be copied from
.Fa dst .
.It Fn rtredirect "struct sockaddr *dst" "struct sockaddr *gateway" \
"struct sockaddr *netmask" "int flags" "struct sockaddr *src" \
"struct rtentry **rtp" "u_int rdomain"
Redirect routes to
.Fa dst
through
.Fa gateway ,
such as in response to an ICMP redirect message.
.Fa src
should be the address from which the redirect message was received.
If
.Fa rtp
is not NULL,
it will be populated by the routing entry corresponding to
.Fa dst .
.It Fn rtdeletemsg "struct rtentry *rt" "u_int tableid"
Delete routing table entry
.Fa rt
from table
.Fa tableid
and forward a notification message to all
.Fa AF_ROUTE
sockets.
.El
.Sh RETURN VALUES
.Fn rt_setgate
may fail with:
.Pp
.Bl -tag -width Er -compact
.It Bq Er ENOBUFS
Memory could not be allocated for the gateway.
.El
.Pp
.Fn rtdeletemsg
may fail with:
.Pp
.Bl -tag -width Er -compact
.It Bq Er EAFNOSUPPORT
The protocol used by
.Fa rt
is not supported by table with ID
.Fa tableid .
.It Bq Er ESRCH
No routing entry for
.Fa rt
could be found.
.It Bq Er ESRCH
.Fa rt
is a multipath routing entry that conflicts with an existing one.
.El
.Sh SEE ALSO
.Xr route 4 ,
.Xr route 8 ,
.Xr rt_timer_add 9 ,
.Xr rtable_add 9 ,
.Xr rtlabel_id2name 9 ,
.Xr rtrequest 9