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freebsd-skq/sys/net/if_gre.c
bz f4689a8d0f gre(4) was using a field in the softc to detect possible recursion. 
On MP systems this is not a usable solution anymore and could easily
lead to false positives triggering enough logging that even  using
the console was no longer usable (multiple parallel ping -f can do).

Switch to the suggested solution of using mbuf tags to carry per
packet state between gre_output() invocations.  Contrary to the
proposed solution modelled after gif(4) only allocate one mbuf tag
per packet rather than per packet and per gre_output() pass through.

As the sysctl to control the possible valid (gre in gre) nestings does
no sanity checks, make sure to always allocate space in the mbuf tag
for at least one, and at most 255 possible gre interfaces to detect
loops in addition to the counter.

Submitted by:	Cristian KLEIN (cristi net.utcluj.ro) (original version)
PR:		kern/114714
Reviewed by:	Cristian KLEIN (cristi net.utcluj.ro)
Reviewed bu:	Wooseog Choi (ben_choi hotmail.com)
Sponsored by:	Sandvine Incorporated
MFC after:	1 week
2011-06-18 09:34:03 +00:00

981 lines
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/* $NetBSD: if_gre.c,v 1.49 2003/12/11 00:22:29 itojun Exp $ */
/* $FreeBSD$ */
/*-
* Copyright (c) 1998 The NetBSD Foundation, Inc.
* 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.
*/
/*
* Encapsulate L3 protocols into IP
* See RFC 2784 (successor of RFC 1701 and 1702) for more details.
* If_gre is compatible with Cisco GRE tunnels, so you can
* have a NetBSD box as the other end of a tunnel interface of a Cisco
* router. See gre(4) for more details.
* Also supported: IP in IP encaps (proto 55) as of RFC 2004
*/
#include "opt_atalk.h"
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/jail.h>
#include <sys/kernel.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/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_clone.h>
#include <net/if_types.h>
#include <net/route.h>
#include <net/vnet.h>
#ifdef INET
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_gre.h>
#include <netinet/ip_var.h>
#include <netinet/ip_encap.h>
#else
#error "Huh? if_gre without inet?"
#endif
#include <net/bpf.h>
#include <net/if_gre.h>
/*
* It is not easy to calculate the right value for a GRE MTU.
* We leave this task to the admin and use the same default that
* other vendors use.
*/
#define GREMTU 1476
#define GRENAME "gre"
#define MTAG_COOKIE_GRE 1307983903
#define MTAG_GRE_NESTING 1
struct mtag_gre_nesting {
uint16_t count;
uint16_t max;
struct ifnet *ifp[];
};
/*
* gre_mtx protects all global variables in if_gre.c.
* XXX: gre_softc data not protected yet.
*/
struct mtx gre_mtx;
static MALLOC_DEFINE(M_GRE, GRENAME, "Generic Routing Encapsulation");
struct gre_softc_head gre_softc_list;
static int gre_clone_create(struct if_clone *, int, caddr_t);
static void gre_clone_destroy(struct ifnet *);
static int gre_ioctl(struct ifnet *, u_long, caddr_t);
static int gre_output(struct ifnet *, struct mbuf *, struct sockaddr *,
struct route *ro);
IFC_SIMPLE_DECLARE(gre, 0);
static int gre_compute_route(struct gre_softc *sc);
static void greattach(void);
#ifdef INET
extern struct domain inetdomain;
static const struct protosw in_gre_protosw = {
.pr_type = SOCK_RAW,
.pr_domain = &inetdomain,
.pr_protocol = IPPROTO_GRE,
.pr_flags = PR_ATOMIC|PR_ADDR,
.pr_input = gre_input,
.pr_output = (pr_output_t *)rip_output,
.pr_ctlinput = rip_ctlinput,
.pr_ctloutput = rip_ctloutput,
.pr_usrreqs = &rip_usrreqs
};
static const struct protosw in_mobile_protosw = {
.pr_type = SOCK_RAW,
.pr_domain = &inetdomain,
.pr_protocol = IPPROTO_MOBILE,
.pr_flags = PR_ATOMIC|PR_ADDR,
.pr_input = gre_mobile_input,
.pr_output = (pr_output_t *)rip_output,
.pr_ctlinput = rip_ctlinput,
.pr_ctloutput = rip_ctloutput,
.pr_usrreqs = &rip_usrreqs
};
#endif
SYSCTL_DECL(_net_link);
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 int max_gre_nesting = MAX_GRE_NEST;
SYSCTL_INT(_net_link_gre, OID_AUTO, max_nesting, CTLFLAG_RW,
&max_gre_nesting, 0, "Max nested tunnels");
/* ARGSUSED */
static void
greattach(void)
{
mtx_init(&gre_mtx, "gre_mtx", NULL, MTX_DEF);
LIST_INIT(&gre_softc_list);
if_clone_attach(&gre_cloner);
}
static int
gre_clone_create(ifc, unit, params)
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);
GRE2IFP(sc) = if_alloc(IFT_TUNNEL);
if (GRE2IFP(sc) == NULL) {
free(sc, M_GRE);
return (ENOSPC);
}
GRE2IFP(sc)->if_softc = sc;
if_initname(GRE2IFP(sc), ifc->ifc_name, unit);
GRE2IFP(sc)->if_snd.ifq_maxlen = ifqmaxlen;
GRE2IFP(sc)->if_addrlen = 0;
GRE2IFP(sc)->if_hdrlen = 24; /* IP + GRE */
GRE2IFP(sc)->if_mtu = GREMTU;
GRE2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
GRE2IFP(sc)->if_output = gre_output;
GRE2IFP(sc)->if_ioctl = gre_ioctl;
sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY;
sc->g_proto = IPPROTO_GRE;
GRE2IFP(sc)->if_flags |= IFF_LINK0;
sc->encap = NULL;
sc->gre_fibnum = curthread->td_proc->p_fibnum;
sc->wccp_ver = WCCP_V1;
sc->key = 0;
if_attach(GRE2IFP(sc));
bpfattach(GRE2IFP(sc), DLT_NULL, sizeof(u_int32_t));
mtx_lock(&gre_mtx);
LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list);
mtx_unlock(&gre_mtx);
return (0);
}
static void
gre_clone_destroy(ifp)
struct ifnet *ifp;
{
struct gre_softc *sc = ifp->if_softc;
mtx_lock(&gre_mtx);
LIST_REMOVE(sc, sc_list);
mtx_unlock(&gre_mtx);
#ifdef INET
if (sc->encap != NULL)
encap_detach(sc->encap);
#endif
bpfdetach(ifp);
if_detach(ifp);
if_free(ifp);
free(sc, M_GRE);
}
/*
* The output routine. Takes a packet and encapsulates it in the protocol
* given by sc->g_proto. See also RFC 1701 and RFC 2004
*/
static int
gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
struct route *ro)
{
int error = 0;
struct gre_softc *sc = ifp->if_softc;
struct greip *gh;
struct ip *ip;
struct m_tag *mtag;
struct mtag_gre_nesting *gt;
size_t len;
u_short gre_ip_id = 0;
uint8_t gre_ip_tos = 0;
u_int16_t etype = 0;
struct mobile_h mob_h;
u_int32_t af;
int extra = 0, max;
/*
* gre may cause infinite recursion calls when misconfigured. High
* nesting level may cause stack exhaustion. We'll prevent this by
* detecting loops and by introducing upper limit.
*/
mtag = m_tag_locate(m, MTAG_COOKIE_GRE, MTAG_GRE_NESTING, NULL);
if (mtag != NULL) {
struct ifnet **ifp2;
gt = (struct mtag_gre_nesting *)(mtag + 1);
gt->count++;
if (gt->count > min(gt->max,max_gre_nesting)) {
printf("%s: hit maximum recursion limit %u on %s\n",
__func__, gt->count - 1, ifp->if_xname);
m_freem(m);
error = EIO; /* is there better errno? */
goto end;
}
ifp2 = gt->ifp;
for (max = gt->count - 1; max > 0; max--) {
if (*ifp2 == ifp)
break;
ifp2++;
}
if (*ifp2 == ifp) {
printf("%s: detected loop with nexting %u on %s\n",
__func__, gt->count-1, ifp->if_xname);
m_freem(m);
error = EIO; /* is there better errno? */
goto end;
}
*ifp2 = ifp;
} else {
/*
* Given that people should NOT increase max_gre_nesting beyond
* their real needs, we allocate once per packet rather than
* allocating an mtag once per passing through gre.
*
* Note: the sysctl does not actually check for saneness, so we
* limit the maximum numbers of possible recursions here.
*/
max = imin(max_gre_nesting, 256);
/* If someone sets the sysctl <= 0, we want at least 1. */
max = imax(max, 1);
len = sizeof(struct mtag_gre_nesting) +
max * sizeof(struct ifnet *);
mtag = m_tag_alloc(MTAG_COOKIE_GRE, MTAG_GRE_NESTING, len,
M_NOWAIT);
if (mtag == NULL) {
m_freem(m);
error = ENOMEM;
goto end;
}
gt = (struct mtag_gre_nesting *)(mtag + 1);
bzero(gt, len);
gt->count = 1;
gt->max = max;
*gt->ifp = ifp;
m_tag_prepend(m, mtag);
}
if (!((ifp->if_flags & IFF_UP) &&
(ifp->if_drv_flags & IFF_DRV_RUNNING)) ||
sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) {
m_freem(m);
error = ENETDOWN;
goto end;
}
gh = NULL;
ip = NULL;
/* 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 (bpf_peers_present(ifp->if_bpf)) {
af = dst->sa_family;
bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
}
m->m_flags &= ~(M_BCAST|M_MCAST);
if (sc->g_proto == IPPROTO_MOBILE) {
if (dst->sa_family == AF_INET) {
struct mbuf *m0;
int msiz;
ip = mtod(m, struct ip *);
/*
* RFC2004 specifies that fragmented diagrams shouldn't
* be encapsulated.
*/
if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
_IF_DROP(&ifp->if_snd);
m_freem(m);
error = EINVAL; /* is there better errno? */
goto end;
}
memset(&mob_h, 0, MOB_H_SIZ_L);
mob_h.proto = (ip->ip_p) << 8;
mob_h.odst = ip->ip_dst.s_addr;
ip->ip_dst.s_addr = sc->g_dst.s_addr;
/*
* If the packet comes from our host, we only change
* the destination address in the IP header.
* Else we also need to save and change the source
*/
if (in_hosteq(ip->ip_src, sc->g_src)) {
msiz = MOB_H_SIZ_S;
} else {
mob_h.proto |= MOB_H_SBIT;
mob_h.osrc = ip->ip_src.s_addr;
ip->ip_src.s_addr = sc->g_src.s_addr;
msiz = MOB_H_SIZ_L;
}
mob_h.proto = htons(mob_h.proto);
mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz);
if ((m->m_data - msiz) < m->m_pktdat) {
/* need new mbuf */
MGETHDR(m0, M_DONTWAIT, MT_DATA);
if (m0 == NULL) {
_IF_DROP(&ifp->if_snd);
m_freem(m);
error = ENOBUFS;
goto end;
}
m0->m_next = m;
m->m_data += sizeof(struct ip);
m->m_len -= sizeof(struct ip);
m0->m_pkthdr.len = m->m_pkthdr.len + msiz;
m0->m_len = msiz + sizeof(struct ip);
m0->m_data += max_linkhdr;
memcpy(mtod(m0, caddr_t), (caddr_t)ip,
sizeof(struct ip));
m = m0;
} else { /* we have some space left in the old one */
m->m_data -= msiz;
m->m_len += msiz;
m->m_pkthdr.len += msiz;
bcopy(ip, mtod(m, caddr_t),
sizeof(struct ip));
}
ip = mtod(m, struct ip *);
memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz);
ip->ip_len = ntohs(ip->ip_len) + msiz;
} else { /* AF_INET */
_IF_DROP(&ifp->if_snd);
m_freem(m);
error = EINVAL;
goto end;
}
} else if (sc->g_proto == IPPROTO_GRE) {
switch (dst->sa_family) {
case AF_INET:
ip = mtod(m, struct ip *);
gre_ip_tos = ip->ip_tos;
gre_ip_id = ip->ip_id;
if (sc->wccp_ver == WCCP_V2) {
extra = sizeof(uint32_t);
etype = WCCP_PROTOCOL_TYPE;
} else {
etype = ETHERTYPE_IP;
}
break;
#ifdef INET6
case AF_INET6:
gre_ip_id = ip_newid();
etype = ETHERTYPE_IPV6;
break;
#endif
#ifdef NETATALK
case AF_APPLETALK:
etype = ETHERTYPE_ATALK;
break;
#endif
default:
_IF_DROP(&ifp->if_snd);
m_freem(m);
error = EAFNOSUPPORT;
goto end;
}
/* Reserve space for GRE header + optional GRE key */
int hdrlen = sizeof(struct greip) + extra;
if (sc->key)
hdrlen += sizeof(uint32_t);
M_PREPEND(m, hdrlen, M_DONTWAIT);
} else {
_IF_DROP(&ifp->if_snd);
m_freem(m);
error = EINVAL;
goto end;
}
if (m == NULL) { /* mbuf allocation failed */
_IF_DROP(&ifp->if_snd);
error = ENOBUFS;
goto end;
}
M_SETFIB(m, sc->gre_fibnum); /* The envelope may use a different FIB */
gh = mtod(m, struct greip *);
if (sc->g_proto == IPPROTO_GRE) {
uint32_t *options = gh->gi_options;
memset((void *)gh, 0, sizeof(struct greip) + extra);
gh->gi_ptype = htons(etype);
gh->gi_flags = 0;
/* Add key option */
if (sc->key)
{
gh->gi_flags |= htons(GRE_KP);
*(options++) = htonl(sc->key);
}
}
gh->gi_pr = sc->g_proto;
if (sc->g_proto != IPPROTO_MOBILE) {
gh->gi_src = sc->g_src;
gh->gi_dst = sc->g_dst;
((struct ip*)gh)->ip_v = IPPROTO_IPV4;
((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2;
((struct ip*)gh)->ip_ttl = GRE_TTL;
((struct ip*)gh)->ip_tos = gre_ip_tos;
((struct ip*)gh)->ip_id = gre_ip_id;
gh->gi_len = m->m_pkthdr.len;
}
ifp->if_opackets++;
ifp->if_obytes += m->m_pkthdr.len;
/*
* Send it off and with IP_FORWARD flag to prevent it from
* overwriting the ip_id again. ip_id is already set to the
* ip_id of the encapsulated packet.
*/
error = ip_output(m, NULL, &sc->route, IP_FORWARDING,
(struct ip_moptions *)NULL, (struct inpcb *)NULL);
end:
if (error)
ifp->if_oerrors++;
return (error);
}
static int
gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
struct ifreq *ifr = (struct ifreq *)data;
struct if_laddrreq *lifr = (struct if_laddrreq *)data;
struct in_aliasreq *aifr = (struct in_aliasreq *)data;
struct gre_softc *sc = ifp->if_softc;
int s;
struct sockaddr_in si;
struct sockaddr *sa = NULL;
int error, adj;
struct sockaddr_in sp, sm, dp, dm;
uint32_t key;
error = 0;
adj = 0;
s = splnet();
switch (cmd) {
case SIOCSIFADDR:
ifp->if_flags |= IFF_UP;
break;
case SIOCSIFDSTADDR:
break;
case SIOCSIFFLAGS:
/*
* XXXRW: Isn't this priv_check() redundant to the ifnet
* layer check?
*/
if ((error = priv_check(curthread, PRIV_NET_SETIFFLAGS)) != 0)
break;
if ((ifr->ifr_flags & IFF_LINK0) != 0)
sc->g_proto = IPPROTO_GRE;
else
sc->g_proto = IPPROTO_MOBILE;
if ((ifr->ifr_flags & IFF_LINK2) != 0)
sc->wccp_ver = WCCP_V2;
else
sc->wccp_ver = WCCP_V1;
goto recompute;
case SIOCSIFMTU:
/*
* XXXRW: Isn't this priv_check() redundant to the ifnet
* layer check?
*/
if ((error = priv_check(curthread, PRIV_NET_SETIFMTU)) != 0)
break;
if (ifr->ifr_mtu < 576) {
error = EINVAL;
break;
}
ifp->if_mtu = ifr->ifr_mtu;
break;
case SIOCGIFMTU:
ifr->ifr_mtu = GRE2IFP(sc)->if_mtu;
break;
case SIOCADDMULTI:
/*
* XXXRW: Isn't this priv_checkr() redundant to the ifnet
* layer check?
*/
if ((error = priv_check(curthread, PRIV_NET_ADDMULTI)) != 0)
break;
if (ifr == 0) {
error = EAFNOSUPPORT;
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 SIOCDELMULTI:
/*
* XXXRW: Isn't this priv_check() redundant to the ifnet
* layer check?
*/
if ((error = priv_check(curthread, PRIV_NET_DELIFGROUP)) != 0)
break;
if (ifr == 0) {
error = EAFNOSUPPORT;
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 GRESPROTO:
/*
* XXXRW: Isn't this priv_check() redundant to the ifnet
* layer check?
*/
if ((error = priv_check(curthread, PRIV_NET_GRE)) != 0)
break;
sc->g_proto = ifr->ifr_flags;
switch (sc->g_proto) {
case IPPROTO_GRE:
ifp->if_flags |= IFF_LINK0;
break;
case IPPROTO_MOBILE:
ifp->if_flags &= ~IFF_LINK0;
break;
default:
error = EPROTONOSUPPORT;
break;
}
goto recompute;
case GREGPROTO:
ifr->ifr_flags = sc->g_proto;
break;
case GRESADDRS:
case GRESADDRD:
error = priv_check(curthread, PRIV_NET_GRE);
if (error)
return (error);
/*
* set tunnel endpoints, compute a less specific route
* to the remote end and mark if as up
*/
sa = &ifr->ifr_addr;
if (cmd == GRESADDRS)
sc->g_src = (satosin(sa))->sin_addr;
if (cmd == GRESADDRD)
sc->g_dst = (satosin(sa))->sin_addr;
recompute:
#ifdef INET
if (sc->encap != NULL) {
encap_detach(sc->encap);
sc->encap = NULL;
}
#endif
if ((sc->g_src.s_addr != INADDR_ANY) &&
(sc->g_dst.s_addr != INADDR_ANY)) {
bzero(&sp, sizeof(sp));
bzero(&sm, sizeof(sm));
bzero(&dp, sizeof(dp));
bzero(&dm, sizeof(dm));
sp.sin_len = sm.sin_len = dp.sin_len = dm.sin_len =
sizeof(struct sockaddr_in);
sp.sin_family = sm.sin_family = dp.sin_family =
dm.sin_family = AF_INET;
sp.sin_addr = sc->g_src;
dp.sin_addr = sc->g_dst;
sm.sin_addr.s_addr = dm.sin_addr.s_addr =
INADDR_BROADCAST;
#ifdef INET
sc->encap = encap_attach(AF_INET, sc->g_proto,
sintosa(&sp), sintosa(&sm), sintosa(&dp),
sintosa(&dm), (sc->g_proto == IPPROTO_GRE) ?
&in_gre_protosw : &in_mobile_protosw, sc);
if (sc->encap == NULL)
printf("%s: unable to attach encap\n",
if_name(GRE2IFP(sc)));
#endif
if (sc->route.ro_rt != 0) /* free old route */
RTFREE(sc->route.ro_rt);
if (gre_compute_route(sc) == 0)
ifp->if_drv_flags |= IFF_DRV_RUNNING;
else
ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
}
break;
case GREGADDRS:
memset(&si, 0, sizeof(si));
si.sin_family = AF_INET;
si.sin_len = sizeof(struct sockaddr_in);
si.sin_addr.s_addr = sc->g_src.s_addr;
sa = sintosa(&si);
error = prison_if(curthread->td_ucred, sa);
if (error != 0)
break;
ifr->ifr_addr = *sa;
break;
case GREGADDRD:
memset(&si, 0, sizeof(si));
si.sin_family = AF_INET;
si.sin_len = sizeof(struct sockaddr_in);
si.sin_addr.s_addr = sc->g_dst.s_addr;
sa = sintosa(&si);
error = prison_if(curthread->td_ucred, sa);
if (error != 0)
break;
ifr->ifr_addr = *sa;
break;
case SIOCSIFPHYADDR:
/*
* XXXRW: Isn't this priv_check() redundant to the ifnet
* layer check?
*/
if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
break;
if (aifr->ifra_addr.sin_family != AF_INET ||
aifr->ifra_dstaddr.sin_family != AF_INET) {
error = EAFNOSUPPORT;
break;
}
if (aifr->ifra_addr.sin_len != sizeof(si) ||
aifr->ifra_dstaddr.sin_len != sizeof(si)) {
error = EINVAL;
break;
}
sc->g_src = aifr->ifra_addr.sin_addr;
sc->g_dst = aifr->ifra_dstaddr.sin_addr;
goto recompute;
case SIOCSLIFPHYADDR:
/*
* XXXRW: Isn't this priv_check() redundant to the ifnet
* layer check?
*/
if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
break;
if (lifr->addr.ss_family != AF_INET ||
lifr->dstaddr.ss_family != AF_INET) {
error = EAFNOSUPPORT;
break;
}
if (lifr->addr.ss_len != sizeof(si) ||
lifr->dstaddr.ss_len != sizeof(si)) {
error = EINVAL;
break;
}
sc->g_src = (satosin(&lifr->addr))->sin_addr;
sc->g_dst =
(satosin(&lifr->dstaddr))->sin_addr;
goto recompute;
case SIOCDIFPHYADDR:
/*
* XXXRW: Isn't this priv_check() redundant to the ifnet
* layer check?
*/
if ((error = priv_check(curthread, PRIV_NET_SETIFPHYS)) != 0)
break;
sc->g_src.s_addr = INADDR_ANY;
sc->g_dst.s_addr = INADDR_ANY;
goto recompute;
case SIOCGLIFPHYADDR:
if (sc->g_src.s_addr == INADDR_ANY ||
sc->g_dst.s_addr == INADDR_ANY) {
error = EADDRNOTAVAIL;
break;
}
memset(&si, 0, sizeof(si));
si.sin_family = AF_INET;
si.sin_len = sizeof(struct sockaddr_in);
si.sin_addr.s_addr = sc->g_src.s_addr;
error = prison_if(curthread->td_ucred, (struct sockaddr *)&si);
if (error != 0)
break;
memcpy(&lifr->addr, &si, sizeof(si));
si.sin_addr.s_addr = sc->g_dst.s_addr;
error = prison_if(curthread->td_ucred, (struct sockaddr *)&si);
if (error != 0)
break;
memcpy(&lifr->dstaddr, &si, sizeof(si));
break;
case SIOCGIFPSRCADDR:
#ifdef INET6
case SIOCGIFPSRCADDR_IN6:
#endif
if (sc->g_src.s_addr == INADDR_ANY) {
error = EADDRNOTAVAIL;
break;
}
memset(&si, 0, sizeof(si));
si.sin_family = AF_INET;
si.sin_len = sizeof(struct sockaddr_in);
si.sin_addr.s_addr = sc->g_src.s_addr;
error = prison_if(curthread->td_ucred, (struct sockaddr *)&si);
if (error != 0)
break;
bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
break;
case SIOCGIFPDSTADDR:
#ifdef INET6
case SIOCGIFPDSTADDR_IN6:
#endif
if (sc->g_dst.s_addr == INADDR_ANY) {
error = EADDRNOTAVAIL;
break;
}
memset(&si, 0, sizeof(si));
si.sin_family = AF_INET;
si.sin_len = sizeof(struct sockaddr_in);
si.sin_addr.s_addr = sc->g_dst.s_addr;
error = prison_if(curthread->td_ucred, (struct sockaddr *)&si);
if (error != 0)
break;
bcopy(&si, &ifr->ifr_addr, sizeof(ifr->ifr_addr));
break;
case GRESKEY:
error = priv_check(curthread, PRIV_NET_GRE);
if (error)
break;
error = copyin(ifr->ifr_data, &key, sizeof(key));
if (error)
break;
/* adjust MTU for option header */
if (key == 0 && sc->key != 0) /* clear */
adj += sizeof(key);
else if (key != 0 && sc->key == 0) /* set */
adj -= sizeof(key);
if (ifp->if_mtu + adj < 576) {
error = EINVAL;
break;
}
ifp->if_mtu += adj;
sc->key = key;
break;
case GREGKEY:
error = copyout(&sc->key, ifr->ifr_data, sizeof(sc->key));
break;
default:
error = EINVAL;
break;
}
splx(s);
return (error);
}
/*
* computes a route to our destination that is not the one
* which would be taken by ip_output(), as this one will loop back to
* us. If the interface is p2p as a--->b, then a routing entry exists
* If we now send a packet to b (e.g. ping b), this will come down here
* gets src=a, dst=b tacked on and would from ip_output() sent back to
* if_gre.
* Goal here is to compute a route to b that is less specific than
* a-->b. We know that this one exists as in normal operation we have
* at least a default route which matches.
*/
static int
gre_compute_route(struct gre_softc *sc)
{
struct route *ro;
ro = &sc->route;
memset(ro, 0, sizeof(struct route));
((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
ro->ro_dst.sa_family = AF_INET;
ro->ro_dst.sa_len = sizeof(ro->ro_dst);
/*
* toggle last bit, so our interface is not found, but a less
* specific route. I'd rather like to specify a shorter mask,
* but this is not possible. Should work though. XXX
* XXX MRT Use a different FIB for the tunnel to solve this problem.
*/
if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0) {
((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr ^=
htonl(0x01);
}
#ifdef DIAGNOSTIC
printf("%s: searching for a route to %s", if_name(GRE2IFP(sc)),
inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr));
#endif
rtalloc_fib(ro, sc->gre_fibnum);
/*
* check if this returned a route at all and this route is no
* recursion to ourself
*/
if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) {
#ifdef DIAGNOSTIC
if (ro->ro_rt == NULL)
printf(" - no route found!\n");
else
printf(" - route loops back to ourself!\n");
#endif
return EADDRNOTAVAIL;
}
/*
* now change it back - else ip_output will just drop
* the route and search one to this interface ...
*/
if ((GRE2IFP(sc)->if_flags & IFF_LINK1) == 0)
((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst;
#ifdef DIAGNOSTIC
printf(", choosing %s with gateway %s", if_name(ro->ro_rt->rt_ifp),
inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr));
printf("\n");
#endif
return 0;
}
/*
* do a checksum of a buffer - much like in_cksum, which operates on
* mbufs.
*/
u_int16_t
gre_in_cksum(u_int16_t *p, u_int len)
{
u_int32_t sum = 0;
int nwords = len >> 1;
while (nwords-- != 0)
sum += *p++;
if (len & 1) {
union {
u_short w;
u_char c[2];
} u;
u.c[0] = *(u_char *)p;
u.c[1] = 0;
sum += u.w;
}
/* end-around-carry */
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16);
return (~sum);
}
static int
gremodevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
greattach();
break;
case MOD_UNLOAD:
if_clone_detach(&gre_cloner);
mtx_destroy(&gre_mtx);
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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