freebsd-skq/sys/net/if_loop.c
Sam Leffler 9c855a36c1 Introduce the notion of "persistent mbuf tags"; these are tags that stay
with an mbuf until it is reclaimed.  This is in contrast to tags that
vanish when an mbuf chain passes through an interface.  Persistent tags
are used, for example, by MAC labels.

Add an m_tag_delete_nonpersistent function to strip non-persistent tags
from mbufs and use it to strip such tags from packets as they pass through
the loopback interface and when turned around by icmp.  This fixes problems
with "tag leakage".

Pointed out by:	Jonathan Stone
Reviewed by:	Robert Watson
2003-10-29 05:40:07 +00:00

433 lines
9.6 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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/mac.h>
#include <sys/malloc.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 <net/if.h>
#include <net/if_types.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/bpf.h>
#include <net/bpfdesc.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
#ifdef TINY_LOMTU
#define LOMTU (1024+512)
#elif defined(LARGE_LOMTU)
#define LOMTU 131072
#else
#define LOMTU 16384
#endif
#define LONAME "lo"
struct lo_softc {
struct ifnet sc_if; /* network-visible interface */
LIST_ENTRY(lo_softc) sc_next;
};
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);
int lo_clone_create(struct if_clone *, int);
void lo_clone_destroy(struct ifnet *);
struct ifnet *loif = NULL; /* Used externally */
static MALLOC_DEFINE(M_LO, LONAME, "Loopback Interface");
static LIST_HEAD(lo_list, lo_softc) lo_list;
struct if_clone lo_cloner = IF_CLONE_INITIALIZER(LONAME,
lo_clone_create, lo_clone_destroy, 1, IF_MAXUNIT);
void
lo_clone_destroy(ifp)
struct ifnet *ifp;
{
struct lo_softc *sc;
sc = ifp->if_softc;
/* XXX: destroying lo0 will lead to panics. */
KASSERT(loif != ifp, ("%s: destroying lo0", __func__));
bpfdetach(ifp);
if_detach(ifp);
LIST_REMOVE(sc, sc_next);
free(sc, M_LO);
}
int
lo_clone_create(ifc, unit)
struct if_clone *ifc;
int unit;
{
struct lo_softc *sc;
MALLOC(sc, struct lo_softc *, sizeof(*sc), M_LO, M_WAITOK | M_ZERO);
sc->sc_if.if_name = LONAME;
sc->sc_if.if_unit = unit;
sc->sc_if.if_mtu = LOMTU;
sc->sc_if.if_flags = IFF_LOOPBACK | IFF_MULTICAST;
sc->sc_if.if_ioctl = loioctl;
sc->sc_if.if_output = looutput;
sc->sc_if.if_type = IFT_LOOP;
sc->sc_if.if_snd.ifq_maxlen = ifqmaxlen;
sc->sc_if.if_softc = sc;
if_attach(&sc->sc_if);
bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
LIST_INSERT_HEAD(&lo_list, sc, sc_next);
if (loif == NULL)
loif = &sc->sc_if;
return (0);
}
static int
loop_modevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
LIST_INIT(&lo_list);
if_clone_attach(&lo_cloner);
break;
case MOD_UNLOAD:
printf("loop module unload - not possible for this module type\n");
return EINVAL;
}
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(ifp, m, dst, rt)
struct ifnet *ifp;
register struct mbuf *m;
struct sockaddr *dst;
register struct rtentry *rt;
{
#ifdef INET6
struct mbuf *n;
#endif
M_ASSERTPKTHDR(m); /* check if we have the packet header */
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);
}
#ifdef INET6
/*
* KAME requires that the packet to be contiguous on the
* mbuf. We need to make that sure.
* this kind of code should be avoided.
*
* XXX: KAME may no longer need contiguous packets. Once
* that has been verified, the following code _should_ be
* removed.
*/
if (m && m->m_next != NULL) {
n = m_defrag(m, M_DONTWAIT);
if (n == NULL) {
m_freem(m);
return (ENOBUFS);
} else {
m = n;
}
}
#endif
ifp->if_opackets++;
ifp->if_obytes += m->m_pkthdr.len;
#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(ifp, m, af, hlen)
struct ifnet *ifp;
struct mbuf *m;
int af;
int hlen;
{
int isr;
M_ASSERTPKTHDR(m);
m_tag_delete_nonpersistent(m);
m->m_pkthdr.rcvif = ifp;
/* BPF write needs to be handled specially */
if (af == AF_UNSPEC) {
KASSERT(m->m_len >= sizeof(int), ("if_simloop: m_len"));
af = *(mtod(m, int *));
m->m_len -= sizeof(int);
m->m_pkthdr.len -= sizeof(int);
m->m_data += sizeof(int);
}
/* Let BPF see incoming packet */
if (ifp->if_bpf) {
struct mbuf m0, *n = m;
if (ifp->if_bpf->bif_dlt == DLT_NULL) {
/*
* We need to prepend the address family as
* a four byte field. Cons up a dummy header
* to pacify bpf. This is safe because bpf
* will only read from the mbuf (i.e., it won't
* try to free it or keep a pointer a to it).
*/
m0.m_next = m;
m0.m_len = 4;
m0.m_data = (char *)&af;
n = &m0;
}
BPF_MTAP(ifp, n);
}
/* Strip away media header */
if (hlen > 0) {
m_adj(m, hlen);
#if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
/* The alpha doesn't like unaligned data.
* 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);
mtod(m,vm_offset_t) -= (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_dispatch(isr, m);
return (0);
}
/* ARGSUSED */
static void
lortrequest(cmd, rt, info)
int cmd;
struct rtentry *rt;
struct rt_addrinfo *info;
{
RT_LOCK_ASSERT(rt);
if (rt) {
rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; /* for ISO */
/*
* For optimal performance, the send and receive buffers
* should be at least twice the MTU plus a little more for
* overhead.
*/
rt->rt_rmx.rmx_recvpipe =
rt->rt_rmx.rmx_sendpipe = 3 * LOMTU;
}
}
/*
* Process an ioctl request.
*/
/* ARGSUSED */
int
loioctl(ifp, cmd, data)
register struct ifnet *ifp;
u_long cmd;
caddr_t data;
{
register struct ifaddr *ifa;
register struct ifreq *ifr = (struct ifreq *)data;
register int error = 0;
switch (cmd) {
case SIOCSIFADDR:
ifp->if_flags |= IFF_UP | IFF_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);
}