.\"     $OpenBSD: rtrequest.9,v 1.3 2019/07/12 16:57:45 mpi Exp $
.\"
.\" Copyright (c) 2011 Bret S. Lambert <blambert@openbsd.org>
.\" All rights reserved.
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" 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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.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: July 12 2019 $
.Dt RTREQUEST 9
.Os
.Sh NAME
.Nm rtrequest
.Nd add or remove entries from a routing table
.Sh SYNOPSIS
.In sys/types.h
.In net/route.h
.Ft int
.Fn rtrequest "int req" "struct rt_addrinfo *info" "u_int8_t prio" \
"struct rtentry **rtp" "u_int rtableid"
.Bd -literal
struct rt_addrinfo {
	int	rti_addrs;
	struct	sockaddr *rti_info[RTAX_MAX];
	int	rti_flags;
	struct	ifaddr *rti_ifa;
	struct	rt_msghdr *rti_rtm;
	u_char	rti_mpls;
};

#define RTAX_DST	0	/* destination sockaddr present */
#define RTAX_GATEWAY	1	/* gateway sockaddr present */
#define RTAX_NETMASK	2	/* netmask sockaddr present */
#define RTAX_IFP	4	/* interface name sockaddr present */
#define RTAX_IFA	5	/* interface addr sockaddr present */
#define RTAX_AUTHOR	6	/* sockaddr for author of redirect */
#define RTAX_BRD	7	/* for NEWADDR, broadcast or p-p dest */
#define RTAX_SRC	8	/* source sockaddr present */
#define RTAX_SRCMASK	9	/* source netmask present */
#define RTAX_LABEL	10	/* route label present */
#define RTAX_MAX	11	/* size of array to allocate */
.Ed
.Sh DESCRIPTION
The
.Fn rtrequest
function is used to add or remove entries from a specific routing table.
It takes the following arguments:
.Bl -tag -width rtableid
.It Fa req
One of the following actions to perform:
.Bl -tag -width RTM_RESOLVE -offset indent
.It Dv RTM_ADD
Add an entry to a given routing table.
.It Dv RTM_DELETE
Remove an entry from a given routing table.
In case of a cloning entry, all its children are deleted.
.It Dv RTM_RESOLVE
Add a cloned entry, based on the parent cloning entry pointed by
.Fa rtp ,
to a given routing table.
.El
.It Fa info
Describes the routing entry to add or remove.
.It Fa prio
Specifies the priority of the routing entry described by
.Fa info .
If it is
.Dv 0
and the requested action is
.Dv RTM_ADD
then a default priority based on the priority of the associated
interface is chosen.
.It Fa rtp
Must point to the cloning entry if the action is
.Dv RTM_RESOLVE .
In all cases when no error is returned and it is not
.Dv NULL ,
a pointer to the deleted or added entry is placed there.
The caller must take care of releasing the returned reference by
calling
.Xr rtfree 9 .
.It Fa rtableid
The ID of the routing table to modify.
.El
.Sh CONTEXT
.Fn rtrequest
can be called during autoconf, from process context, or from interrupt context.
.Sh RETURN VALUES
.Fn rtrequest
may fail with:
.Pp
.Bl -tag -width Er -compact
.It Bq Er EAFNOSUPPORT
The routing table with ID of
.Fa rtableid
does not exist or it does not support the protocol specified in
.Fa info .
.It Bq Er ESRCH
No routing entry corresponding to
.Fa info
could be found.
.It Bq Er ESRCH
Multipath routing entry with no gateway provided in
.Fa info .
.It Bq Er ESRCH
The entry could not be found in the routing table of ID
.Fa rtableid .
specified
.It Bq Er EINVAL
The entry pointed by
.Fa rtp
is not valid or does not point to a cloning entry in the
.Dv RTM_RESOLVE
case.
.It Bq Er EEXIST
Multipath routing entry conflicts with an existing one.
.It Bq Er EEXIST
The entry could not be entered into the routing table.
.It Bq Er ENOMEM
Space for MPLS protocol data could not be allocated.
.It Bq Er ENOBUFS
Space for a new routing entry could not be allocated.
.It Bq Er ENETUNREACH
An interface address corresponding to the routing entry described by
.Fa info
could not be found.
.El
.Sh SEE ALSO
.Xr rtfree 9