freebsd-dev/sys/net/if_disc.c
Zhenlei Huang 62e1a437f3 routing: Allow using IPv6 next-hops for IPv4 routes (RFC 5549).
Implement kernel support for RFC 5549/8950.

* Relax control plane restrictions and allow specifying IPv6 gateways
 for IPv4 routes. This behavior is controlled by the
 net.route.rib_route_ipv6_nexthop sysctl (on by default).

* Always pass final destination in ro->ro_dst in ip_forward().

* Use ro->ro_dst to exract packet family inside if_output() routines.
 Consistently use RO_GET_FAMILY() macro to handle ro=NULL case.

* Pass extracted family to nd6_resolve() to get the LLE with proper encap.
 It leverages recent lltable changes committed in c541bd368f.

Presence of the functionality can be checked using ipv4_rfc5549_support feature(3).
Example usage:
  route add -net 192.0.0.0/24 -inet6 fe80::5054:ff:fe14:e319%vtnet0

Differential Revision: https://reviews.freebsd.org/D30398
MFC after:	2 weeks
2021-08-22 22:56:08 +00:00

247 lines
6.0 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1982, 1986, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93
* $FreeBSD$
*/
/*
* Discard interface driver for protocol testing and timing.
* (Based on the loopback.)
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_clone.h>
#include <net/if_types.h>
#include <net/route.h>
#include <net/bpf.h>
#include <net/vnet.h>
#include "opt_inet.h"
#include "opt_inet6.h"
#ifdef TINY_DSMTU
#define DSMTU (1024+512)
#else
#define DSMTU 65532
#endif
struct disc_softc {
struct ifnet *sc_ifp;
};
static int discoutput(struct ifnet *, struct mbuf *,
const struct sockaddr *, struct route *);
static int discioctl(struct ifnet *, u_long, caddr_t);
static int disc_clone_create(struct if_clone *, int, caddr_t);
static void disc_clone_destroy(struct ifnet *);
static const char discname[] = "disc";
static MALLOC_DEFINE(M_DISC, discname, "Discard interface");
VNET_DEFINE_STATIC(struct if_clone *, disc_cloner);
#define V_disc_cloner VNET(disc_cloner)
static int
disc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
struct ifnet *ifp;
struct disc_softc *sc;
sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
if (ifp == NULL) {
free(sc, M_DISC);
return (ENOSPC);
}
ifp->if_softc = sc;
if_initname(ifp, discname, unit);
ifp->if_mtu = DSMTU;
/*
* IFF_LOOPBACK should not be removed from disc's flags because
* it controls what PF-specific routes are magically added when
* a network address is assigned to the interface. Things just
* won't work as intended w/o such routes because the output
* interface selection for a packet is totally route-driven.
* A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or
* IFF_POINTOPOINT, but it would result in different properties
* of the interface.
*/
ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
ifp->if_drv_flags = IFF_DRV_RUNNING;
ifp->if_ioctl = discioctl;
ifp->if_output = discoutput;
ifp->if_hdrlen = 0;
ifp->if_addrlen = 0;
ifp->if_snd.ifq_maxlen = 20;
if_attach(ifp);
bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
return (0);
}
static void
disc_clone_destroy(struct ifnet *ifp)
{
struct disc_softc *sc;
sc = ifp->if_softc;
bpfdetach(ifp);
if_detach(ifp);
if_free(ifp);
free(sc, M_DISC);
}
static void
vnet_disc_init(const void *unused __unused)
{
V_disc_cloner = if_clone_simple(discname, disc_clone_create,
disc_clone_destroy, 0);
}
VNET_SYSINIT(vnet_disc_init, SI_SUB_PSEUDO, SI_ORDER_ANY,
vnet_disc_init, NULL);
static void
vnet_disc_uninit(const void *unused __unused)
{
if_clone_detach(V_disc_cloner);
}
VNET_SYSUNINIT(vnet_disc_uninit, SI_SUB_INIT_IF, SI_ORDER_ANY,
vnet_disc_uninit, NULL);
static int
disc_modevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
case MOD_UNLOAD:
break;
default:
return (EOPNOTSUPP);
}
return (0);
}
static moduledata_t disc_mod = {
"if_disc",
disc_modevent,
NULL
};
DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
static int
discoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
struct route *ro)
{
u_int32_t af;
M_ASSERTPKTHDR(m);
/* BPF writes need to be handled specially. */
if (dst->sa_family == AF_UNSPEC)
bcopy(dst->sa_data, &af, sizeof(af));
else
af = RO_GET_FAMILY(ro, dst);
if (bpf_peers_present(ifp->if_bpf))
bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
m->m_pkthdr.rcvif = ifp;
if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
m_freem(m);
return (0);
}
/*
* Process an ioctl request.
*/
static int
discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
struct ifreq *ifr = (struct ifreq *)data;
int error = 0;
switch (cmd) {
case SIOCSIFADDR:
ifp->if_flags |= IFF_UP;
/*
* Everything else is done at a higher level.
*/
break;
case SIOCADDMULTI:
case SIOCDELMULTI:
if (ifr == NULL) {
error = EAFNOSUPPORT; /* XXX */
break;
}
switch (ifr->ifr_addr.sa_family) {
#ifdef INET
case AF_INET:
break;
#endif
#ifdef INET6
case AF_INET6:
break;
#endif
default:
error = EAFNOSUPPORT;
break;
}
break;
case SIOCSIFMTU:
ifp->if_mtu = ifr->ifr_mtu;
break;
default:
error = EINVAL;
}
return (error);
}