freebsd-dev/sys/net/if_loop.c
Robert Watson 3dc85f8d63 Do invoke mac_ifnet_check_transmit() and mac_ifnet_create_mbuf()
in the loopback and synthetic loopback code so that packets are
access control checked and relabeled.  Previously, the MAC
Framework enforced that packets sent over the loopback weren't
relabeled, but this will allow policies to make explicit choices
about how and whether to relabel packets on the loopback.  Also,
for SIMPLEX devices, this produces more consistent behavior for
looped back packets to the local MAC address by labeling those
packets as coming from the interface.

Discussed with:	csjp
Obtained from:	TrustedBSD Project
2009-01-10 23:50:23 +00:00

398 lines
8.7 KiB
C

/*-
* 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.
* 4. 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.
*
* @(#)if_loop.c 8.2 (Berkeley) 1/9/95
* $FreeBSD$
*/
/*
* Loopback interface driver for protocol testing and timing.
*/
#include "opt_atalk.h"
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_ipx.h"
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <machine/bus.h>
#include <sys/rman.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <sys/vimage.h>
#include <net/if.h>
#include <net/if_clone.h>
#include <net/if_types.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/bpf.h>
#include <net/vnet.h>
#ifdef INET
#include <netinet/in.h>
#include <netinet/in_var.h>
#endif
#ifdef IPX
#include <netipx/ipx.h>
#include <netipx/ipx_if.h>
#endif
#ifdef INET6
#ifndef INET
#include <netinet/in.h>
#endif
#include <netinet6/in6_var.h>
#include <netinet/ip6.h>
#endif
#ifdef NETATALK
#include <netatalk/at.h>
#include <netatalk/at_var.h>
#endif
#include <security/mac/mac_framework.h>
#ifdef TINY_LOMTU
#define LOMTU (1024+512)
#elif defined(LARGE_LOMTU)
#define LOMTU 131072
#else
#define LOMTU 16384
#endif
int loioctl(struct ifnet *, u_long, caddr_t);
static void lortrequest(int, struct rtentry *, struct rt_addrinfo *);
int looutput(struct ifnet *ifp, struct mbuf *m,
struct sockaddr *dst, struct rtentry *rt);
static int lo_clone_create(struct if_clone *, int, caddr_t);
static void lo_clone_destroy(struct ifnet *);
#ifdef VIMAGE_GLOBALS
struct ifnet *loif; /* Used externally */
#endif
IFC_SIMPLE_DECLARE(lo, 1);
static void
lo_clone_destroy(struct ifnet *ifp)
{
#ifdef INVARIANTS
INIT_VNET_NET(ifp->if_vnet);
#endif
/* XXX: destroying lo0 will lead to panics. */
KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
bpfdetach(ifp);
if_detach(ifp);
if_free(ifp);
}
static int
lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
INIT_VNET_NET(curvnet);
struct ifnet *ifp;
ifp = if_alloc(IFT_LOOP);
if (ifp == NULL)
return (ENOSPC);
if_initname(ifp, ifc->ifc_name, unit);
ifp->if_mtu = LOMTU;
ifp->if_flags = IFF_LOOPBACK | IFF_MULTICAST;
ifp->if_ioctl = loioctl;
ifp->if_output = looutput;
ifp->if_snd.ifq_maxlen = ifqmaxlen;
if_attach(ifp);
bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
if (V_loif == NULL)
V_loif = ifp;
return (0);
}
static int
loop_modevent(module_t mod, int type, void *data)
{
INIT_VNET_NET(curvnet);
switch (type) {
case MOD_LOAD:
V_loif = NULL;
if_clone_attach(&lo_cloner);
break;
case MOD_UNLOAD:
printf("loop module unload - not possible for this module type\n");
return (EINVAL);
default:
return (EOPNOTSUPP);
}
return (0);
}
static moduledata_t loop_mod = {
"loop",
loop_modevent,
0
};
DECLARE_MODULE(loop, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
int
looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
struct rtentry *rt)
{
u_int32_t af;
#ifdef MAC
int error;
#endif
M_ASSERTPKTHDR(m); /* check if we have the packet header */
#ifdef MAC
error = mac_ifnet_check_transmit(ifp, m);
if (error) {
m_freem(m);
return (error);
}
#endif
if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
m_freem(m);
return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
}
ifp->if_opackets++;
ifp->if_obytes += m->m_pkthdr.len;
/* BPF writes need to be handled specially. */
if (dst->sa_family == AF_UNSPEC) {
bcopy(dst->sa_data, &af, sizeof(af));
dst->sa_family = af;
}
#if 1 /* XXX */
switch (dst->sa_family) {
case AF_INET:
case AF_INET6:
case AF_IPX:
case AF_APPLETALK:
break;
default:
printf("looutput: af=%d unexpected\n", dst->sa_family);
m_freem(m);
return (EAFNOSUPPORT);
}
#endif
return (if_simloop(ifp, m, dst->sa_family, 0));
}
/*
* if_simloop()
*
* This function is to support software emulation of hardware loopback,
* i.e., for interfaces with the IFF_SIMPLEX attribute. Since they can't
* hear their own broadcasts, we create a copy of the packet that we
* would normally receive via a hardware loopback.
*
* This function expects the packet to include the media header of length hlen.
*/
int
if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen)
{
INIT_VNET_NET(ifp->if_vnet);
int isr;
M_ASSERTPKTHDR(m);
m_tag_delete_nonpersistent(m);
m->m_pkthdr.rcvif = ifp;
#ifdef MAC
mac_ifnet_create_mbuf(ifp, m);
#endif
/*
* Let BPF see incoming packet in the following manner:
* - Emulated packet loopback for a simplex interface
* (net/if_ethersubr.c)
* -> passes it to ifp's BPF
* - IPv4/v6 multicast packet loopback (netinet(6)/ip(6)_output.c)
* -> not passes it to any BPF
* - Normal packet loopback from myself to myself (net/if_loop.c)
* -> passes to lo0's BPF (even in case of IPv6, where ifp!=lo0)
*/
if (hlen > 0) {
if (bpf_peers_present(ifp->if_bpf)) {
bpf_mtap(ifp->if_bpf, m);
}
} else {
if (bpf_peers_present(V_loif->if_bpf)) {
if ((m->m_flags & M_MCAST) == 0 || V_loif == ifp) {
/* XXX beware sizeof(af) != 4 */
u_int32_t af1 = af;
/*
* We need to prepend the address family.
*/
bpf_mtap2(V_loif->if_bpf, &af1, sizeof(af1), m);
}
}
}
/* Strip away media header */
if (hlen > 0) {
m_adj(m, hlen);
#ifndef __NO_STRICT_ALIGNMENT
/*
* Some archs do not like unaligned data, so
* we move data down in the first mbuf.
*/
if (mtod(m, vm_offset_t) & 3) {
KASSERT(hlen >= 3, ("if_simloop: hlen too small"));
bcopy(m->m_data,
(char *)(mtod(m, vm_offset_t)
- (mtod(m, vm_offset_t) & 3)),
m->m_len);
m->m_data -= (mtod(m,vm_offset_t) & 3);
}
#endif
}
/* Deliver to upper layer protocol */
switch (af) {
#ifdef INET
case AF_INET:
isr = NETISR_IP;
break;
#endif
#ifdef INET6
case AF_INET6:
m->m_flags |= M_LOOP;
isr = NETISR_IPV6;
break;
#endif
#ifdef IPX
case AF_IPX:
isr = NETISR_IPX;
break;
#endif
#ifdef NETATALK
case AF_APPLETALK:
isr = NETISR_ATALK2;
break;
#endif
default:
printf("if_simloop: can't handle af=%d\n", af);
m_freem(m);
return (EAFNOSUPPORT);
}
ifp->if_ipackets++;
ifp->if_ibytes += m->m_pkthdr.len;
netisr_queue(isr, m); /* mbuf is free'd on failure. */
return (0);
}
/* ARGSUSED */
static void
lortrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
{
RT_LOCK_ASSERT(rt);
rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
}
/*
* Process an ioctl request.
*/
/* ARGSUSED */
int
loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
struct ifaddr *ifa;
struct ifreq *ifr = (struct ifreq *)data;
int error = 0;
switch (cmd) {
case SIOCSIFADDR:
ifp->if_flags |= IFF_UP;
ifp->if_drv_flags |= IFF_DRV_RUNNING;
ifa = (struct ifaddr *)data;
ifa->ifa_rtrequest = lortrequest;
/*
* Everything else is done at a higher level.
*/
break;
case SIOCADDMULTI:
case SIOCDELMULTI:
if (ifr == 0) {
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;
case SIOCSIFFLAGS:
break;
default:
error = EINVAL;
}
return (error);
}