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f-stack/freebsd/net/if_gre.c

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/*-
* Copyright (c) 1998 The NetBSD Foundation, Inc.
* Copyright (c) 2014 Andrey V. Elsukov <ae@FreeBSD.org>
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Heiko W.Rupp <hwr@pilhuhn.de>
*
* IPv6-over-GRE contributed by Gert Doering <gert@greenie.muc.de>
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*
* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/libkern.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mbuf.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/rmlock.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <net/ethernet.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/vnet.h>
#include <net/route.h>
#include <netinet/in.h>
#ifdef INET
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#endif
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/in6_var.h>
#include <netinet6/ip6_var.h>
#include <netinet6/scope6_var.h>
#endif
#include <netinet/ip_encap.h>
#include <net/bpf.h>
#include <net/if_gre.h>
#include <machine/in_cksum.h>
#include <security/mac/mac_framework.h>
#define GREMTU 1500
static const char grename[] = "gre";
static MALLOC_DEFINE(M_GRE, grename, "Generic Routing Encapsulation");
static VNET_DEFINE(struct mtx, gre_mtx);
#define V_gre_mtx VNET(gre_mtx)
#define GRE_LIST_LOCK_INIT(x) mtx_init(&V_gre_mtx, "gre_mtx", NULL, \
MTX_DEF)
#define GRE_LIST_LOCK_DESTROY(x) mtx_destroy(&V_gre_mtx)
#define GRE_LIST_LOCK(x) mtx_lock(&V_gre_mtx)
#define GRE_LIST_UNLOCK(x) mtx_unlock(&V_gre_mtx)
static VNET_DEFINE(LIST_HEAD(, gre_softc), gre_softc_list);
#define V_gre_softc_list VNET(gre_softc_list)
static struct sx gre_ioctl_sx;
SX_SYSINIT(gre_ioctl_sx, &gre_ioctl_sx, "gre_ioctl");
static int gre_clone_create(struct if_clone *, int, caddr_t);
static void gre_clone_destroy(struct ifnet *);
static VNET_DEFINE(struct if_clone *, gre_cloner);
#define V_gre_cloner VNET(gre_cloner)
static void gre_qflush(struct ifnet *);
static int gre_transmit(struct ifnet *, struct mbuf *);
static int gre_ioctl(struct ifnet *, u_long, caddr_t);
static int gre_output(struct ifnet *, struct mbuf *,
const struct sockaddr *, struct route *);
static void gre_updatehdr(struct gre_softc *);
static int gre_set_tunnel(struct ifnet *, struct sockaddr *,
struct sockaddr *);
static void gre_delete_tunnel(struct ifnet *);
SYSCTL_DECL(_net_link);
static SYSCTL_NODE(_net_link, IFT_TUNNEL, gre, CTLFLAG_RW, 0,
"Generic Routing Encapsulation");
#ifndef MAX_GRE_NEST
/*
* This macro controls the default upper limitation on nesting of gre tunnels.
* Since, setting a large value to this macro with a careless configuration
* may introduce system crash, we don't allow any nestings by default.
* If you need to configure nested gre tunnels, you can define this macro
* in your kernel configuration file. However, if you do so, please be
* careful to configure the tunnels so that it won't make a loop.
*/
#define MAX_GRE_NEST 1
#endif
static VNET_DEFINE(int, max_gre_nesting) = MAX_GRE_NEST;
#define V_max_gre_nesting VNET(max_gre_nesting)
SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW | CTLFLAG_VNET,
&VNET_NAME(max_gre_nesting), 0, "Max nested tunnels");
static void
vnet_gre_init(const void *unused __unused)
{
LIST_INIT(&V_gre_softc_list);
GRE_LIST_LOCK_INIT();
V_gre_cloner = if_clone_simple(grename, gre_clone_create,
gre_clone_destroy, 0);
}
VNET_SYSINIT(vnet_gre_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
vnet_gre_init, NULL);
static void
vnet_gre_uninit(const void *unused __unused)
{
if_clone_detach(V_gre_cloner);
GRE_LIST_LOCK_DESTROY();
}
VNET_SYSUNINIT(vnet_gre_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
vnet_gre_uninit, NULL);
static int
gre_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
struct gre_softc *sc;
sc = malloc(sizeof(struct gre_softc), M_GRE, M_WAITOK | M_ZERO);
sc->gre_fibnum = curthread->td_proc->p_fibnum;
GRE2IFP(sc) = if_alloc(IFT_TUNNEL);
GRE_LOCK_INIT(sc);
GRE2IFP(sc)->if_softc = sc;
if_initname(GRE2IFP(sc), grename, unit);
GRE2IFP(sc)->if_mtu = sc->gre_mtu = GREMTU;
GRE2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
GRE2IFP(sc)->if_output = gre_output;
GRE2IFP(sc)->if_ioctl = gre_ioctl;
GRE2IFP(sc)->if_transmit = gre_transmit;
GRE2IFP(sc)->if_qflush = gre_qflush;
GRE2IFP(sc)->if_capabilities |= IFCAP_LINKSTATE;
GRE2IFP(sc)->if_capenable |= IFCAP_LINKSTATE;
if_attach(GRE2IFP(sc));
bpfattach(GRE2IFP(sc), DLT_NULL, sizeof(u_int32_t));
GRE_LIST_LOCK();
LIST_INSERT_HEAD(&V_gre_softc_list, sc, gre_list);
GRE_LIST_UNLOCK();
return (0);
}
static void
gre_clone_destroy(struct ifnet *ifp)
{
struct gre_softc *sc;
sx_xlock(&gre_ioctl_sx);
sc = ifp->if_softc;
gre_delete_tunnel(ifp);
GRE_LIST_LOCK();
LIST_REMOVE(sc, gre_list);
GRE_LIST_UNLOCK();
bpfdetach(ifp);
if_detach(ifp);
ifp->if_softc = NULL;
sx_xunlock(&gre_ioctl_sx);
if_free(ifp);
GRE_LOCK_DESTROY(sc);
free(sc, M_GRE);
}
static int
gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
GRE_RLOCK_TRACKER;
struct ifreq *ifr = (struct ifreq *)data;
struct sockaddr *src, *dst;
struct gre_softc *sc;
#ifdef INET
struct sockaddr_in *sin = NULL;
#endif
#ifdef INET6
struct sockaddr_in6 *sin6 = NULL;
#endif
uint32_t opt;
int error;
switch (cmd) {
case SIOCSIFMTU:
/* XXX: */
if (ifr->ifr_mtu < 576)
return (EINVAL);
break;
case SIOCSIFADDR:
ifp->if_flags |= IFF_UP;
case SIOCSIFFLAGS:
case SIOCADDMULTI:
case SIOCDELMULTI:
return (0);
case GRESADDRS:
case GRESADDRD:
case GREGADDRS:
case GREGADDRD:
case GRESPROTO:
case GREGPROTO:
return (EOPNOTSUPP);
}
src = dst = NULL;
sx_xlock(&gre_ioctl_sx);
sc = ifp->if_softc;
if (sc == NULL) {
error = ENXIO;
goto end;
}
error = 0;
switch (cmd) {
case SIOCSIFMTU:
GRE_WLOCK(sc);
sc->gre_mtu = ifr->ifr_mtu;
gre_updatehdr(sc);
GRE_WUNLOCK(sc);
goto end;
case SIOCSIFPHYADDR:
#ifdef INET6
case SIOCSIFPHYADDR_IN6:
#endif
error = EINVAL;
switch (cmd) {
#ifdef INET
case SIOCSIFPHYADDR:
src = (struct sockaddr *)
&(((struct in_aliasreq *)data)->ifra_addr);
dst = (struct sockaddr *)
&(((struct in_aliasreq *)data)->ifra_dstaddr);
break;
#endif
#ifdef INET6
case SIOCSIFPHYADDR_IN6:
src = (struct sockaddr *)
&(((struct in6_aliasreq *)data)->ifra_addr);
dst = (struct sockaddr *)
&(((struct in6_aliasreq *)data)->ifra_dstaddr);
break;
#endif
default:
error = EAFNOSUPPORT;
goto end;
}
/* sa_family must be equal */
if (src->sa_family != dst->sa_family ||
src->sa_len != dst->sa_len)
goto end;
/* validate sa_len */
switch (src->sa_family) {
#ifdef INET
case AF_INET:
if (src->sa_len != sizeof(struct sockaddr_in))
goto end;
break;
#endif
#ifdef INET6
case AF_INET6:
if (src->sa_len != sizeof(struct sockaddr_in6))
goto end;
break;
#endif
default:
error = EAFNOSUPPORT;
goto end;
}
/* check sa_family looks sane for the cmd */
error = EAFNOSUPPORT;
switch (cmd) {
#ifdef INET
case SIOCSIFPHYADDR:
if (src->sa_family == AF_INET)
break;
goto end;
#endif
#ifdef INET6
case SIOCSIFPHYADDR_IN6:
if (src->sa_family == AF_INET6)
break;
goto end;
#endif
}
error = EADDRNOTAVAIL;
switch (src->sa_family) {
#ifdef INET
case AF_INET:
if (satosin(src)->sin_addr.s_addr == INADDR_ANY ||
satosin(dst)->sin_addr.s_addr == INADDR_ANY)
goto end;
break;
#endif
#ifdef INET6
case AF_INET6:
if (IN6_IS_ADDR_UNSPECIFIED(&satosin6(src)->sin6_addr)
||
IN6_IS_ADDR_UNSPECIFIED(&satosin6(dst)->sin6_addr))
goto end;
/*
* Check validity of the scope zone ID of the
* addresses, and convert it into the kernel
* internal form if necessary.
*/
error = sa6_embedscope(satosin6(src), 0);
if (error != 0)
goto end;
error = sa6_embedscope(satosin6(dst), 0);
if (error != 0)
goto end;
#endif
}
error = gre_set_tunnel(ifp, src, dst);
break;
case SIOCDIFPHYADDR:
gre_delete_tunnel(ifp);
break;
case SIOCGIFPSRCADDR:
case SIOCGIFPDSTADDR:
#ifdef INET6
case SIOCGIFPSRCADDR_IN6:
case SIOCGIFPDSTADDR_IN6:
#endif
if (sc->gre_family == 0) {
error = EADDRNOTAVAIL;
break;
}
GRE_RLOCK(sc);
switch (cmd) {
#ifdef INET
case SIOCGIFPSRCADDR:
case SIOCGIFPDSTADDR:
if (sc->gre_family != AF_INET) {
error = EADDRNOTAVAIL;
break;
}
sin = (struct sockaddr_in *)&ifr->ifr_addr;
memset(sin, 0, sizeof(*sin));
sin->sin_family = AF_INET;
sin->sin_len = sizeof(*sin);
break;
#endif
#ifdef INET6
case SIOCGIFPSRCADDR_IN6:
case SIOCGIFPDSTADDR_IN6:
if (sc->gre_family != AF_INET6) {
error = EADDRNOTAVAIL;
break;
}
sin6 = (struct sockaddr_in6 *)
&(((struct in6_ifreq *)data)->ifr_addr);
memset(sin6, 0, sizeof(*sin6));
sin6->sin6_family = AF_INET6;
sin6->sin6_len = sizeof(*sin6);
break;
#endif
}
if (error == 0) {
switch (cmd) {
#ifdef INET
case SIOCGIFPSRCADDR:
sin->sin_addr = sc->gre_oip.ip_src;
break;
case SIOCGIFPDSTADDR:
sin->sin_addr = sc->gre_oip.ip_dst;
break;
#endif
#ifdef INET6
case SIOCGIFPSRCADDR_IN6:
sin6->sin6_addr = sc->gre_oip6.ip6_src;
break;
case SIOCGIFPDSTADDR_IN6:
sin6->sin6_addr = sc->gre_oip6.ip6_dst;
break;
#endif
}
}
GRE_RUNLOCK(sc);
if (error != 0)
break;
switch (cmd) {
#ifdef INET
case SIOCGIFPSRCADDR:
case SIOCGIFPDSTADDR:
error = prison_if(curthread->td_ucred,
(struct sockaddr *)sin);
if (error != 0)
memset(sin, 0, sizeof(*sin));
break;
#endif
#ifdef INET6
case SIOCGIFPSRCADDR_IN6:
case SIOCGIFPDSTADDR_IN6:
error = prison_if(curthread->td_ucred,
(struct sockaddr *)sin6);
if (error == 0)
error = sa6_recoverscope(sin6);
if (error != 0)
memset(sin6, 0, sizeof(*sin6));
#endif
}
break;
case SIOCGTUNFIB:
ifr->ifr_fib = sc->gre_fibnum;
break;
case SIOCSTUNFIB:
if ((error = priv_check(curthread, PRIV_NET_GRE)) != 0)
break;
if (ifr->ifr_fib >= rt_numfibs)
error = EINVAL;
else
sc->gre_fibnum = ifr->ifr_fib;
break;
case GRESKEY:
if ((error = priv_check(curthread, PRIV_NET_GRE)) != 0)
break;
if ((error = copyin(ifr->ifr_data, &opt, sizeof(opt))) != 0)
break;
if (sc->gre_key != opt) {
GRE_WLOCK(sc);
sc->gre_key = opt;
gre_updatehdr(sc);
GRE_WUNLOCK(sc);
}
break;
case GREGKEY:
error = copyout(&sc->gre_key, ifr->ifr_data,
sizeof(sc->gre_key));
break;
case GRESOPTS:
if ((error = priv_check(curthread, PRIV_NET_GRE)) != 0)
break;
if ((error = copyin(ifr->ifr_data, &opt, sizeof(opt))) != 0)
break;
if (opt & ~GRE_OPTMASK)
error = EINVAL;
else {
if (sc->gre_options != opt) {
GRE_WLOCK(sc);
sc->gre_options = opt;
gre_updatehdr(sc);
GRE_WUNLOCK(sc);
}
}
break;
case GREGOPTS:
error = copyout(&sc->gre_options, ifr->ifr_data,
sizeof(sc->gre_options));
break;
default:
error = EINVAL;
break;
}
end:
sx_xunlock(&gre_ioctl_sx);
return (error);
}
static void
gre_updatehdr(struct gre_softc *sc)
{
struct grehdr *gh = NULL;
uint32_t *opts;
uint16_t flags;
GRE_WLOCK_ASSERT(sc);
switch (sc->gre_family) {
#ifdef INET
case AF_INET:
sc->gre_hlen = sizeof(struct greip);
sc->gre_oip.ip_v = IPPROTO_IPV4;
sc->gre_oip.ip_hl = sizeof(struct ip) >> 2;
sc->gre_oip.ip_p = IPPROTO_GRE;
gh = &sc->gre_gihdr->gi_gre;
break;
#endif
#ifdef INET6
case AF_INET6:
sc->gre_hlen = sizeof(struct greip6);
sc->gre_oip6.ip6_vfc = IPV6_VERSION;
sc->gre_oip6.ip6_nxt = IPPROTO_GRE;
gh = &sc->gre_gi6hdr->gi6_gre;
break;
#endif
default:
return;
}
flags = 0;
opts = gh->gre_opts;
if (sc->gre_options & GRE_ENABLE_CSUM) {
flags |= GRE_FLAGS_CP;
sc->gre_hlen += 2 * sizeof(uint16_t);
*opts++ = 0;
}
if (sc->gre_key != 0) {
flags |= GRE_FLAGS_KP;
sc->gre_hlen += sizeof(uint32_t);
*opts++ = htonl(sc->gre_key);
}
if (sc->gre_options & GRE_ENABLE_SEQ) {
flags |= GRE_FLAGS_SP;
sc->gre_hlen += sizeof(uint32_t);
*opts++ = 0;
} else
sc->gre_oseq = 0;
gh->gre_flags = htons(flags);
GRE2IFP(sc)->if_mtu = sc->gre_mtu - sc->gre_hlen;
}
static void
gre_detach(struct gre_softc *sc)
{
sx_assert(&gre_ioctl_sx, SA_XLOCKED);
if (sc->gre_ecookie != NULL)
encap_detach(sc->gre_ecookie);
sc->gre_ecookie = NULL;
}
static int
gre_set_tunnel(struct ifnet *ifp, struct sockaddr *src,
struct sockaddr *dst)
{
struct gre_softc *sc, *tsc;
#ifdef INET6
struct ip6_hdr *ip6;
#endif
#ifdef INET
struct ip *ip;
#endif
void *hdr;
int error;
sx_assert(&gre_ioctl_sx, SA_XLOCKED);
GRE_LIST_LOCK();
sc = ifp->if_softc;
LIST_FOREACH(tsc, &V_gre_softc_list, gre_list) {
if (tsc == sc || tsc->gre_family != src->sa_family)
continue;
#ifdef INET
if (tsc->gre_family == AF_INET &&
tsc->gre_oip.ip_src.s_addr ==
satosin(src)->sin_addr.s_addr &&
tsc->gre_oip.ip_dst.s_addr ==
satosin(dst)->sin_addr.s_addr) {
GRE_LIST_UNLOCK();
return (EADDRNOTAVAIL);
}
#endif
#ifdef INET6
if (tsc->gre_family == AF_INET6 &&
IN6_ARE_ADDR_EQUAL(&tsc->gre_oip6.ip6_src,
&satosin6(src)->sin6_addr) &&
IN6_ARE_ADDR_EQUAL(&tsc->gre_oip6.ip6_dst,
&satosin6(dst)->sin6_addr)) {
GRE_LIST_UNLOCK();
return (EADDRNOTAVAIL);
}
#endif
}
GRE_LIST_UNLOCK();
switch (src->sa_family) {
#ifdef INET
case AF_INET:
hdr = ip = malloc(sizeof(struct greip) +
3 * sizeof(uint32_t), M_GRE, M_WAITOK | M_ZERO);
ip->ip_src = satosin(src)->sin_addr;
ip->ip_dst = satosin(dst)->sin_addr;
break;
#endif
#ifdef INET6
case AF_INET6:
hdr = ip6 = malloc(sizeof(struct greip6) +
3 * sizeof(uint32_t), M_GRE, M_WAITOK | M_ZERO);
ip6->ip6_src = satosin6(src)->sin6_addr;
ip6->ip6_dst = satosin6(dst)->sin6_addr;
break;
#endif
default:
return (EAFNOSUPPORT);
}
if (sc->gre_family != 0)
gre_detach(sc);
GRE_WLOCK(sc);
if (sc->gre_family != 0)
free(sc->gre_hdr, M_GRE);
sc->gre_family = src->sa_family;
sc->gre_hdr = hdr;
sc->gre_oseq = 0;
sc->gre_iseq = UINT32_MAX;
gre_updatehdr(sc);
GRE_WUNLOCK(sc);
error = 0;
switch (src->sa_family) {
#ifdef INET
case AF_INET:
error = in_gre_attach(sc);
break;
#endif
#ifdef INET6
case AF_INET6:
error = in6_gre_attach(sc);
break;
#endif
}
if (error == 0) {
ifp->if_drv_flags |= IFF_DRV_RUNNING;
if_link_state_change(ifp, LINK_STATE_UP);
}
return (error);
}
static void
gre_delete_tunnel(struct ifnet *ifp)
{
struct gre_softc *sc = ifp->if_softc;
int family;
GRE_WLOCK(sc);
family = sc->gre_family;
sc->gre_family = 0;
GRE_WUNLOCK(sc);
if (family != 0) {
gre_detach(sc);
free(sc->gre_hdr, M_GRE);
}
ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
if_link_state_change(ifp, LINK_STATE_DOWN);
}
int
gre_input(struct mbuf **mp, int *offp, int proto)
{
struct gre_softc *sc;
struct grehdr *gh;
struct ifnet *ifp;
struct mbuf *m;
uint32_t *opts;
#ifdef notyet
uint32_t key;
#endif
uint16_t flags;
int hlen, isr, af;
m = *mp;
sc = encap_getarg(m);
KASSERT(sc != NULL, ("encap_getarg returned NULL"));
ifp = GRE2IFP(sc);
hlen = *offp + sizeof(struct grehdr) + 4 * sizeof(uint32_t);
if (m->m_pkthdr.len < hlen)
goto drop;
if (m->m_len < hlen) {
m = m_pullup(m, hlen);
if (m == NULL)
goto drop;
}
gh = (struct grehdr *)mtodo(m, *offp);
flags = ntohs(gh->gre_flags);
if (flags & ~GRE_FLAGS_MASK)
goto drop;
opts = gh->gre_opts;
hlen = 2 * sizeof(uint16_t);
if (flags & GRE_FLAGS_CP) {
/* reserved1 field must be zero */
if (((uint16_t *)opts)[1] != 0)
goto drop;
if (in_cksum_skip(m, m->m_pkthdr.len, *offp) != 0)
goto drop;
hlen += 2 * sizeof(uint16_t);
opts++;
}
if (flags & GRE_FLAGS_KP) {
#ifdef notyet
/*
* XXX: The current implementation uses the key only for outgoing
* packets. But we can check the key value here, or even in the
* encapcheck function.
*/
key = ntohl(*opts);
#endif
hlen += sizeof(uint32_t);
opts++;
}
#ifdef notyet
} else
key = 0;
if (sc->gre_key != 0 && (key != sc->gre_key || key != 0))
goto drop;
#endif
if (flags & GRE_FLAGS_SP) {
#ifdef notyet
seq = ntohl(*opts);
#endif
hlen += sizeof(uint32_t);
}
switch (ntohs(gh->gre_proto)) {
case ETHERTYPE_WCCP:
/*
* For WCCP skip an additional 4 bytes if after GRE header
* doesn't follow an IP header.
*/
if (flags == 0 && (*(uint8_t *)gh->gre_opts & 0xF0) != 0x40)
hlen += sizeof(uint32_t);
/* FALLTHROUGH */
case ETHERTYPE_IP:
isr = NETISR_IP;
af = AF_INET;
break;
case ETHERTYPE_IPV6:
isr = NETISR_IPV6;
af = AF_INET6;
break;
default:
goto drop;
}
m_adj(m, *offp + hlen);
m_clrprotoflags(m);
m->m_pkthdr.rcvif = ifp;
M_SETFIB(m, ifp->if_fib);
#ifdef MAC
mac_ifnet_create_mbuf(ifp, m);
#endif
BPF_MTAP2(ifp, &af, sizeof(af), m);
if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
if ((ifp->if_flags & IFF_MONITOR) != 0)
m_freem(m);
else
netisr_dispatch(isr, m);
return (IPPROTO_DONE);
drop:
if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
m_freem(m);
return (IPPROTO_DONE);
}
#define MTAG_GRE 1307983903
static int
gre_check_nesting(struct ifnet *ifp, struct mbuf *m)
{
struct m_tag *mtag;
int count;
count = 1;
mtag = NULL;
while ((mtag = m_tag_locate(m, MTAG_GRE, 0, mtag)) != NULL) {
if (*(struct ifnet **)(mtag + 1) == ifp) {
log(LOG_NOTICE, "%s: loop detected\n", ifp->if_xname);
return (EIO);
}
count++;
}
if (count > V_max_gre_nesting) {
log(LOG_NOTICE,
"%s: if_output recursively called too many times(%d)\n",
ifp->if_xname, count);
return (EIO);
}
mtag = m_tag_alloc(MTAG_GRE, 0, sizeof(struct ifnet *), M_NOWAIT);
if (mtag == NULL)
return (ENOMEM);
*(struct ifnet **)(mtag + 1) = ifp;
m_tag_prepend(m, mtag);
return (0);
}
static int
gre_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
struct route *ro)
{
uint32_t af;
int error;
#ifdef MAC
error = mac_ifnet_check_transmit(ifp, m);
if (error != 0)
goto drop;
#endif
if ((ifp->if_flags & IFF_MONITOR) != 0 ||
(ifp->if_flags & IFF_UP) == 0) {
error = ENETDOWN;
goto drop;
}
error = gre_check_nesting(ifp, m);
if (error != 0)
goto drop;
m->m_flags &= ~(M_BCAST|M_MCAST);
if (dst->sa_family == AF_UNSPEC)
bcopy(dst->sa_data, &af, sizeof(af));
else
af = dst->sa_family;
BPF_MTAP2(ifp, &af, sizeof(af), m);
m->m_pkthdr.csum_data = af; /* save af for if_transmit */
return (ifp->if_transmit(ifp, m));
drop:
m_freem(m);
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
return (error);
}
static void
gre_setseqn(struct grehdr *gh, uint32_t seq)
{
uint32_t *opts;
uint16_t flags;
opts = gh->gre_opts;
flags = ntohs(gh->gre_flags);
KASSERT((flags & GRE_FLAGS_SP) != 0,
("gre_setseqn called, but GRE_FLAGS_SP isn't set "));
if (flags & GRE_FLAGS_CP)
opts++;
if (flags & GRE_FLAGS_KP)
opts++;
*opts = htonl(seq);
}
static int
gre_transmit(struct ifnet *ifp, struct mbuf *m)
{
GRE_RLOCK_TRACKER;
struct gre_softc *sc;
struct grehdr *gh;
uint32_t iaf, oaf, oseq;
int error, hlen, olen, plen;
int want_seq, want_csum;
plen = 0;
sc = ifp->if_softc;
if (sc == NULL) {
error = ENETDOWN;
m_freem(m);
goto drop;
}
GRE_RLOCK(sc);
if (sc->gre_family == 0) {
GRE_RUNLOCK(sc);
error = ENETDOWN;
m_freem(m);
goto drop;
}
iaf = m->m_pkthdr.csum_data;
oaf = sc->gre_family;
hlen = sc->gre_hlen;
want_seq = (sc->gre_options & GRE_ENABLE_SEQ) != 0;
if (want_seq)
oseq = sc->gre_oseq++; /* XXX */
else
oseq = 0; /* Make compiler happy. */
want_csum = (sc->gre_options & GRE_ENABLE_CSUM) != 0;
M_SETFIB(m, sc->gre_fibnum);
M_PREPEND(m, hlen, M_NOWAIT);
if (m == NULL) {
GRE_RUNLOCK(sc);
error = ENOBUFS;
goto drop;
}
bcopy(sc->gre_hdr, mtod(m, void *), hlen);
GRE_RUNLOCK(sc);
switch (oaf) {
#ifdef INET
case AF_INET:
olen = sizeof(struct ip);
break;
#endif
#ifdef INET6
case AF_INET6:
olen = sizeof(struct ip6_hdr);
break;
#endif
default:
error = ENETDOWN;
goto drop;
}
gh = (struct grehdr *)mtodo(m, olen);
switch (iaf) {
#ifdef INET
case AF_INET:
gh->gre_proto = htons(ETHERTYPE_IP);
break;
#endif
#ifdef INET6
case AF_INET6:
gh->gre_proto = htons(ETHERTYPE_IPV6);
break;
#endif
default:
error = ENETDOWN;
goto drop;
}
if (want_seq)
gre_setseqn(gh, oseq);
if (want_csum) {
*(uint16_t *)gh->gre_opts = in_cksum_skip(m,
m->m_pkthdr.len, olen);
}
plen = m->m_pkthdr.len - hlen;
switch (oaf) {
#ifdef INET
case AF_INET:
error = in_gre_output(m, iaf, hlen);
break;
#endif
#ifdef INET6
case AF_INET6:
error = in6_gre_output(m, iaf, hlen);
break;
#endif
default:
m_freem(m);
error = ENETDOWN;
}
drop:
if (error)
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
else {
if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
if_inc_counter(ifp, IFCOUNTER_OBYTES, plen);
}
return (error);
}
static void
gre_qflush(struct ifnet *ifp __unused)
{
}
static int
gremodevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
case MOD_UNLOAD:
break;
default:
return (EOPNOTSUPP);
}
return (0);
}
static moduledata_t gre_mod = {
"if_gre",
gremodevent,
0
};
DECLARE_MODULE(if_gre, gre_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
MODULE_VERSION(if_gre, 1);
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