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freebsd-dev/sys/net/if_loop.c
Alexander V. Chernikov 36402a681f Finish r275196: do not dereference rtentry in if_output() routines. 
The only piece of information that is required is rt_flags subset.

In particular, if_loop() requires RTF_REJECT and RTF_BLACKHOLE flags
  to check if this particular mbuf needs to be dropped (and what
  error should be returned).
Note that if_loop() will always return EHOSTUNREACH for "reject" routes
  regardless of RTF_HOST flag existence. This is due to upcoming routing
  changes where RTF_HOST value won't be available as lookup result.

All other functions require RTF_GATEWAY flag to check if they need
  to return EHOSTUNREACH instead of EHOSTDOWN error.

There are 11 places where non-zero 'struct route' is passed to if_output().
For most of the callers (forwarding, bpf, arp) does not care about exact
  error value. In fact, the only place where this result is propagated
  is ip_output(). (ip6_output() passes NULL route to nd6_output_ifp()).

Given that, add 3 new 'struct route' flags (RT_REJECT, RT_BLACKHOLE and
  RT_IS_GW) and inline function (rt_update_ro_flags()) to copy necessary
  rte flags to ro_flags. Call this function in ip_output() after looking up/
  verifying rte.

Reviewed by:	ae
2016-01-09 16:34:37 +00:00

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/*-
* 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_inet.h"
#include "opt_inet6.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 <net/if.h>
#include <net/if_var.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 INET6
#ifndef INET
#include <netinet/in.h>
#endif
#include <netinet6/in6_var.h>
#include <netinet/ip6.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
#define LO_CSUM_FEATURES (CSUM_IP | CSUM_TCP | CSUM_UDP | CSUM_SCTP)
#define LO_CSUM_FEATURES6 (CSUM_TCP_IPV6 | CSUM_UDP_IPV6 | CSUM_SCTP_IPV6)
#define LO_CSUM_SET (CSUM_DATA_VALID | CSUM_DATA_VALID_IPV6 | \
CSUM_PSEUDO_HDR | \
CSUM_IP_CHECKED | CSUM_IP_VALID | \
CSUM_SCTP_VALID)
int loioctl(struct ifnet *, u_long, caddr_t);
int looutput(struct ifnet *ifp, struct mbuf *m,
const struct sockaddr *dst, struct route *ro);
static int lo_clone_create(struct if_clone *, int, caddr_t);
static void lo_clone_destroy(struct ifnet *);
VNET_DEFINE(struct ifnet *, loif); /* Used externally */
#ifdef VIMAGE
static VNET_DEFINE(struct if_clone *, lo_cloner);
#define V_lo_cloner VNET(lo_cloner)
#endif
static struct if_clone *lo_cloner;
static const char loname[] = "lo";
static void
lo_clone_destroy(struct ifnet *ifp)
{
#ifndef VIMAGE
/* XXX: destroying lo0 will lead to panics. */
KASSERT(V_loif != ifp, ("%s: destroying lo0", __func__));
#endif
bpfdetach(ifp);
if_detach(ifp);
if_free(ifp);
}
static int
lo_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
struct ifnet *ifp;
ifp = if_alloc(IFT_LOOP);
if (ifp == NULL)
return (ENOSPC);
if_initname(ifp, loname, 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;
ifp->if_capabilities = ifp->if_capenable =
IFCAP_HWCSUM | IFCAP_HWCSUM_IPV6;
ifp->if_hwassist = LO_CSUM_FEATURES | LO_CSUM_FEATURES6;
if_attach(ifp);
bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
if (V_loif == NULL)
V_loif = ifp;
return (0);
}
static void
vnet_loif_init(const void *unused __unused)
{
#ifdef VIMAGE
lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
1);
V_lo_cloner = lo_cloner;
#else
lo_cloner = if_clone_simple(loname, lo_clone_create, lo_clone_destroy,
1);
#endif
}
VNET_SYSINIT(vnet_loif_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
vnet_loif_init, NULL);
#ifdef VIMAGE
static void
vnet_loif_uninit(const void *unused __unused)
{
if_clone_detach(V_lo_cloner);
V_loif = NULL;
}
VNET_SYSUNINIT(vnet_loif_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
vnet_loif_uninit, NULL);
#endif
static int
loop_modevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
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 = {
"if_lo",
loop_modevent,
0
};
DECLARE_MODULE(if_lo, loop_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
int
looutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
struct route *ro)
{
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 (ro != NULL && ro->ro_flags & (RT_REJECT|RT_BLACKHOLE)) {
m_freem(m);
return (ro->ro_flags & RT_BLACKHOLE ? 0 : EHOSTUNREACH);
}
if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
/* BPF writes need to be handled specially. */
if (dst->sa_family == AF_UNSPEC || dst->sa_family == pseudo_AF_HDRCMPLT)
bcopy(dst->sa_data, &af, sizeof(af));
else
af = dst->sa_family;
#if 1 /* XXX */
switch (af) {
case AF_INET:
if (ifp->if_capenable & IFCAP_RXCSUM) {
m->m_pkthdr.csum_data = 0xffff;
m->m_pkthdr.csum_flags = LO_CSUM_SET;
}
m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES;
break;
case AF_INET6:
#if 0
/*
* XXX-BZ for now always claim the checksum is good despite
* any interface flags. This is a workaround for 9.1-R and
* a proper solution ought to be sought later.
*/
if (ifp->if_capenable & IFCAP_RXCSUM_IPV6) {
m->m_pkthdr.csum_data = 0xffff;
m->m_pkthdr.csum_flags = LO_CSUM_SET;
}
#else
m->m_pkthdr.csum_data = 0xffff;
m->m_pkthdr.csum_flags = LO_CSUM_SET;
#endif
m->m_pkthdr.csum_flags &= ~LO_CSUM_FEATURES6;
break;
default:
printf("looutput: af=%d unexpected\n", af);
m_freem(m);
return (EAFNOSUPPORT);
}
#endif
return (if_simloop(ifp, m, af, 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)
{
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
default:
printf("if_simloop: can't handle af=%d\n", af);
m_freem(m);
return (EAFNOSUPPORT);
}
if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
netisr_queue(isr, m); /* mbuf is free'd on failure. */
return (0);
}
/*
* Process an ioctl request.
*/
/* ARGSUSED */
int
loioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
struct ifreq *ifr = (struct ifreq *)data;
int error = 0, mask;
switch (cmd) {
case SIOCSIFADDR:
ifp->if_flags |= IFF_UP;
ifp->if_drv_flags |= IFF_DRV_RUNNING;
/*
* 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;
case SIOCSIFCAP:
mask = ifp->if_capenable ^ ifr->ifr_reqcap;
if ((mask & IFCAP_RXCSUM) != 0)
ifp->if_capenable ^= IFCAP_RXCSUM;
if ((mask & IFCAP_TXCSUM) != 0)
ifp->if_capenable ^= IFCAP_TXCSUM;
if ((mask & IFCAP_RXCSUM_IPV6) != 0) {
#if 0
ifp->if_capenable ^= IFCAP_RXCSUM_IPV6;
#else
error = EOPNOTSUPP;
break;
#endif
}
if ((mask & IFCAP_TXCSUM_IPV6) != 0) {
#if 0
ifp->if_capenable ^= IFCAP_TXCSUM_IPV6;
#else
error = EOPNOTSUPP;
break;
#endif
}
ifp->if_hwassist = 0;
if (ifp->if_capenable & IFCAP_TXCSUM)
ifp->if_hwassist = LO_CSUM_FEATURES;
#if 0
if (ifp->if_capenable & IFCAP_TXCSUM_IPV6)
ifp->if_hwassist |= LO_CSUM_FEATURES6;
#endif
break;
default:
error = EINVAL;
}
return (error);
}
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