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1a75e3b20f
Some virtual if drivers has (ab)used ifa ifa_rtrequest hook to enforce route MTU to be not bigger that interface MTU. While ifa_rtrequest hooking might be an option in some situation, it is not feasible to do MTU checks there: generic (or per-domain) routing code is perfectly capable of doing this. We currrently have 3 places where MTU is altered: 1) route addition. In this case domain overrides radix _addroute callback (in[6]_addroute) and all necessary checks/fixes are/can be done there. 2) route change (especially, GW change). In this case, there are no explicit per-domain calls, but one can override rte by setting ifa_rtrequest hook to domain handler (inet6 does this). 3) ifconfig ifaceX mtu YYYY In this case, we have no callbacks, but ip[6]_output performes runtime checks and decreases rt_mtu if necessary. Generally, the goals are to be able to handle all MTU changes in control plane, not in runtime part, and properly deal with increased interface MTU. This commit changes the following: * removes hooks setting MTU from drivers side * adds proper per-doman MTU checks for case 1) * adds generic MTU check for case 2) * The latter is done by using new dom_ifmtu callback since if_mtu denotes L3 interface MTU, e.g. maximum trasmitted _packet_ size. However, IPv6 mtu might be different from if_mtu one (e.g. default 1280) for some cases, so we need an abstract way to know maximum MTU size for given interface and domain. * moves rt_setmetrics() before MTU/ifa_rtrequest hooks since it copies user-supplied data which must be checked. * removes RT_LOCK_ASSERT() from other ifa_rtrequest hooks to be able to use this functions on new non-inserted rte. More changes will follow soon. MFC after: 1 month Sponsored by: Yandex LLC
245 lines
5.9 KiB
C
245 lines
5.9 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* From: @(#)if_loop.c 8.1 (Berkeley) 6/10/93
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* $FreeBSD$
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*/
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/*
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* Discard interface driver for protocol testing and timing.
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* (Based on the loopback.)
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/sockio.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/if_clone.h>
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#include <net/if_types.h>
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#include <net/route.h>
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#include <net/bpf.h>
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#include <net/vnet.h>
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#ifdef TINY_DSMTU
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#define DSMTU (1024+512)
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#else
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#define DSMTU 65532
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#endif
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struct disc_softc {
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struct ifnet *sc_ifp;
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};
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static int discoutput(struct ifnet *, struct mbuf *,
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const struct sockaddr *, struct route *);
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static int discioctl(struct ifnet *, u_long, caddr_t);
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static int disc_clone_create(struct if_clone *, int, caddr_t);
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static void disc_clone_destroy(struct ifnet *);
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static const char discname[] = "disc";
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static MALLOC_DEFINE(M_DISC, discname, "Discard interface");
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static VNET_DEFINE(struct if_clone *, disc_cloner);
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#define V_disc_cloner VNET(disc_cloner)
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static int
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disc_clone_create(struct if_clone *ifc, int unit, caddr_t params)
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{
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struct ifnet *ifp;
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struct disc_softc *sc;
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sc = malloc(sizeof(struct disc_softc), M_DISC, M_WAITOK | M_ZERO);
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ifp = sc->sc_ifp = if_alloc(IFT_LOOP);
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if (ifp == NULL) {
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free(sc, M_DISC);
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return (ENOSPC);
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}
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ifp->if_softc = sc;
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if_initname(ifp, discname, unit);
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ifp->if_mtu = DSMTU;
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/*
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* IFF_LOOPBACK should not be removed from disc's flags because
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* it controls what PF-specific routes are magically added when
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* a network address is assigned to the interface. Things just
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* won't work as intended w/o such routes because the output
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* interface selection for a packet is totally route-driven.
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* A valid alternative to IFF_LOOPBACK can be IFF_BROADCAST or
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* IFF_POINTOPOINT, but it would result in different properties
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* of the interface.
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*/
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ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
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ifp->if_drv_flags = IFF_DRV_RUNNING;
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ifp->if_ioctl = discioctl;
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ifp->if_output = discoutput;
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ifp->if_hdrlen = 0;
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ifp->if_addrlen = 0;
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ifp->if_snd.ifq_maxlen = 20;
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if_attach(ifp);
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bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
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return (0);
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}
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static void
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disc_clone_destroy(struct ifnet *ifp)
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{
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struct disc_softc *sc;
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sc = ifp->if_softc;
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bpfdetach(ifp);
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if_detach(ifp);
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if_free(ifp);
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free(sc, M_DISC);
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}
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static void
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vnet_disc_init(const void *unused __unused)
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{
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V_disc_cloner = if_clone_simple(discname, disc_clone_create,
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disc_clone_destroy, 0);
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}
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VNET_SYSINIT(vnet_disc_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
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vnet_disc_init, NULL);
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static void
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vnet_disc_uninit(const void *unused __unused)
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{
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if_clone_detach(V_disc_cloner);
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}
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VNET_SYSUNINIT(vnet_disc_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
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vnet_disc_uninit, NULL);
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static int
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disc_modevent(module_t mod, int type, void *data)
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{
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switch (type) {
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case MOD_LOAD:
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case MOD_UNLOAD:
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break;
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default:
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return (EOPNOTSUPP);
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}
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return (0);
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}
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static moduledata_t disc_mod = {
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"if_disc",
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disc_modevent,
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NULL
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};
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DECLARE_MODULE(if_disc, disc_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
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static int
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discoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
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struct route *ro)
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{
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u_int32_t af;
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M_ASSERTPKTHDR(m);
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/* BPF writes need to be handled specially. */
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if (dst->sa_family == AF_UNSPEC)
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bcopy(dst->sa_data, &af, sizeof(af));
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else
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af = dst->sa_family;
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if (bpf_peers_present(ifp->if_bpf))
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bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
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m->m_pkthdr.rcvif = ifp;
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if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
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if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
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m_freem(m);
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return (0);
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}
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/*
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* Process an ioctl request.
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*/
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static int
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discioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
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{
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struct ifreq *ifr = (struct ifreq *)data;
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int error = 0;
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switch (cmd) {
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case SIOCSIFADDR:
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ifp->if_flags |= IFF_UP;
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/*
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* Everything else is done at a higher level.
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*/
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break;
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case SIOCADDMULTI:
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case SIOCDELMULTI:
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if (ifr == 0) {
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error = EAFNOSUPPORT; /* XXX */
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break;
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}
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switch (ifr->ifr_addr.sa_family) {
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#ifdef INET
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case AF_INET:
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break;
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#endif
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#ifdef INET6
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case AF_INET6:
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break;
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#endif
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default:
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error = EAFNOSUPPORT;
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break;
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}
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break;
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case SIOCSIFMTU:
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ifp->if_mtu = ifr->ifr_mtu;
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break;
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default:
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error = EINVAL;
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}
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return (error);
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}
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