/*-
* Copyright (c) 2014 Andrey V. Elsukov <ae@FreeBSD.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#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/bpf.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>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_encap.h>
#include <machine/in_cksum.h>
#include <security/mac/mac_framework.h>
#define MEMTU 1500
static const char mename[] = "me";
static MALLOC_DEFINE(M_IFME, mename, "Minimal Encapsulation for IP");
static VNET_DEFINE(struct mtx, me_mtx);
#define V_me_mtx VNET(me_mtx)
/* Minimal forwarding header RFC 2004 */
struct mobhdr {
uint8_t mob_proto; /* protocol */
uint8_t mob_flags; /* flags */
#define MOB_FLAGS_SP 0x80 /* source present */
uint16_t mob_csum; /* header checksum */
struct in_addr mob_dst; /* original destination address */
struct in_addr mob_src; /* original source addr (optional) */
} __packed;
struct me_softc {
struct ifnet *me_ifp;
LIST_ENTRY(me_softc) me_list;
struct rmlock me_lock;
u_int me_fibnum;
const struct encaptab *me_ecookie;
struct in_addr me_src;
struct in_addr me_dst;
};
#define ME2IFP(sc) ((sc)->me_ifp)
#define ME_READY(sc) ((sc)->me_src.s_addr != 0)
#define ME_LOCK_INIT(sc) rm_init(&(sc)->me_lock, "me softc")
#define ME_LOCK_DESTROY(sc) rm_destroy(&(sc)->me_lock)
#define ME_RLOCK_TRACKER struct rm_priotracker me_tracker
#define ME_RLOCK(sc) rm_rlock(&(sc)->me_lock, &me_tracker)
#define ME_RUNLOCK(sc) rm_runlock(&(sc)->me_lock, &me_tracker)
#define ME_RLOCK_ASSERT(sc) rm_assert(&(sc)->me_lock, RA_RLOCKED)
#define ME_WLOCK(sc) rm_wlock(&(sc)->me_lock)
#define ME_WUNLOCK(sc) rm_wunlock(&(sc)->me_lock)
#define ME_WLOCK_ASSERT(sc) rm_assert(&(sc)->me_lock, RA_WLOCKED)
#define ME_LIST_LOCK_INIT(x) mtx_init(&V_me_mtx, "me_mtx", NULL, MTX_DEF)
#define ME_LIST_LOCK_DESTROY(x) mtx_destroy(&V_me_mtx)
#define ME_LIST_LOCK(x) mtx_lock(&V_me_mtx)
#define ME_LIST_UNLOCK(x) mtx_unlock(&V_me_mtx)
static VNET_DEFINE(LIST_HEAD(, me_softc), me_softc_list);
#define V_me_softc_list VNET(me_softc_list)
static struct sx me_ioctl_sx;
SX_SYSINIT(me_ioctl_sx, &me_ioctl_sx, "me_ioctl");
static int me_clone_create(struct if_clone *, int, caddr_t);
static void me_clone_destroy(struct ifnet *);
static VNET_DEFINE(struct if_clone *, me_cloner);
#define V_me_cloner VNET(me_cloner)
static void me_qflush(struct ifnet *);
static int me_transmit(struct ifnet *, struct mbuf *);
static int me_ioctl(struct ifnet *, u_long, caddr_t);
static int me_output(struct ifnet *, struct mbuf *,
const struct sockaddr *, struct route *);
static int me_input(struct mbuf **, int *, int);
static int me_set_tunnel(struct ifnet *, struct sockaddr_in *,
struct sockaddr_in *);
static void me_delete_tunnel(struct ifnet *);
SYSCTL_DECL(_net_link);
static SYSCTL_NODE(_net_link, IFT_TUNNEL, me, CTLFLAG_RW, 0,
"Minimal Encapsulation for IP (RFC 2004)");
#ifndef MAX_ME_NEST
#define MAX_ME_NEST 1
#endif
static VNET_DEFINE(int, max_me_nesting) = MAX_ME_NEST;
#define V_max_me_nesting VNET(max_me_nesting)
SYSCTL_INT(_net_link_me, OID_AUTO, max_nesting, CTLFLAG_RW | CTLFLAG_VNET,
&VNET_NAME(max_me_nesting), 0, "Max nested tunnels");
extern struct domain inetdomain;
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 = me_input,
.pr_output = rip_output,
.pr_ctlinput = rip_ctlinput,
.pr_ctloutput = rip_ctloutput,
.pr_usrreqs = &rip_usrreqs
};
static void
vnet_me_init(const void *unused __unused)
{
LIST_INIT(&V_me_softc_list);
ME_LIST_LOCK_INIT();
V_me_cloner = if_clone_simple(mename, me_clone_create,
me_clone_destroy, 0);
}
VNET_SYSINIT(vnet_me_init, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
vnet_me_init, NULL);
static void
vnet_me_uninit(const void *unused __unused)
{
if_clone_detach(V_me_cloner);
ME_LIST_LOCK_DESTROY();
}
VNET_SYSUNINIT(vnet_me_uninit, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY,
vnet_me_uninit, NULL);
static int
me_clone_create(struct if_clone *ifc, int unit, caddr_t params)
{
struct me_softc *sc;
sc = malloc(sizeof(struct me_softc), M_IFME, M_WAITOK | M_ZERO);
sc->me_fibnum = curthread->td_proc->p_fibnum;
ME2IFP(sc) = if_alloc(IFT_TUNNEL);
ME_LOCK_INIT(sc);
ME2IFP(sc)->if_softc = sc;
if_initname(ME2IFP(sc), mename, unit);
ME2IFP(sc)->if_mtu = MEMTU - sizeof(struct mobhdr);
ME2IFP(sc)->if_flags = IFF_POINTOPOINT|IFF_MULTICAST;
ME2IFP(sc)->if_output = me_output;
ME2IFP(sc)->if_ioctl = me_ioctl;
ME2IFP(sc)->if_transmit = me_transmit;
ME2IFP(sc)->if_qflush = me_qflush;
ME2IFP(sc)->if_capabilities |= IFCAP_LINKSTATE;
ME2IFP(sc)->if_capenable |= IFCAP_LINKSTATE;
if_attach(ME2IFP(sc));
bpfattach(ME2IFP(sc), DLT_NULL, sizeof(u_int32_t));
ME_LIST_LOCK();
LIST_INSERT_HEAD(&V_me_softc_list, sc, me_list);
ME_LIST_UNLOCK();
return (0);
}
static void
me_clone_destroy(struct ifnet *ifp)
{
struct me_softc *sc;
sx_xlock(&me_ioctl_sx);
sc = ifp->if_softc;
me_delete_tunnel(ifp);
ME_LIST_LOCK();
LIST_REMOVE(sc, me_list);
ME_LIST_UNLOCK();
bpfdetach(ifp);
if_detach(ifp);
ifp->if_softc = NULL;
sx_xunlock(&me_ioctl_sx);
if_free(ifp);
ME_LOCK_DESTROY(sc);
free(sc, M_IFME);
}
static int
me_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
ME_RLOCK_TRACKER;
struct ifreq *ifr = (struct ifreq *)data;
struct sockaddr_in *src, *dst;
struct me_softc *sc;
int error;
switch (cmd) {
case SIOCSIFMTU:
if (ifr->ifr_mtu < 576)
return (EINVAL);
ifp->if_mtu = ifr->ifr_mtu - sizeof(struct mobhdr);
return (0);
case SIOCSIFADDR:
ifp->if_flags |= IFF_UP;
case SIOCSIFFLAGS:
case SIOCADDMULTI:
case SIOCDELMULTI:
return (0);
}
sx_xlock(&me_ioctl_sx);
sc = ifp->if_softc;
if (sc == NULL) {
error = ENXIO;
goto end;
}
error = 0;
switch (cmd) {
case SIOCSIFPHYADDR:
src = (struct sockaddr_in *)
&(((struct in_aliasreq *)data)->ifra_addr);
dst = (struct sockaddr_in *)
&(((struct in_aliasreq *)data)->ifra_dstaddr);
if (src->sin_family != dst->sin_family ||
src->sin_family != AF_INET ||
src->sin_len != dst->sin_len ||
src->sin_len != sizeof(struct sockaddr_in)) {
error = EINVAL;
break;
}
if (src->sin_addr.s_addr == INADDR_ANY ||
dst->sin_addr.s_addr == INADDR_ANY) {
error = EADDRNOTAVAIL;
break;
}
error = me_set_tunnel(ifp, src, dst);
break;
case SIOCDIFPHYADDR:
me_delete_tunnel(ifp);
break;
case SIOCGIFPSRCADDR:
case SIOCGIFPDSTADDR:
ME_RLOCK(sc);
if (!ME_READY(sc)) {
error = EADDRNOTAVAIL;
ME_RUNLOCK(sc);
break;
}
src = (struct sockaddr_in *)&ifr->ifr_addr;
memset(src, 0, sizeof(*src));
src->sin_family = AF_INET;
src->sin_len = sizeof(*src);
switch (cmd) {
case SIOCGIFPSRCADDR:
src->sin_addr = sc->me_src;
break;
case SIOCGIFPDSTADDR:
src->sin_addr = sc->me_dst;
break;
}
ME_RUNLOCK(sc);
error = prison_if(curthread->td_ucred, sintosa(src));
if (error != 0)
memset(src, 0, sizeof(*src));
break;
case SIOCGTUNFIB:
ifr->ifr_fib = sc->me_fibnum;
break;
case SIOCSTUNFIB:
if ((error = priv_check(curthread, PRIV_NET_GRE)) != 0)
break;
if (ifr->ifr_fib >= rt_numfibs)
error = EINVAL;
else
sc->me_fibnum = ifr->ifr_fib;
break;
default:
error = EINVAL;
break;
}
end:
sx_xunlock(&me_ioctl_sx);
return (error);
}
static int
me_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
{
ME_RLOCK_TRACKER;
struct me_softc *sc;
struct ip *ip;
int ret;
sc = (struct me_softc *)arg;
if ((ME2IFP(sc)->if_flags & IFF_UP) == 0)
return (0);
M_ASSERTPKTHDR(m);
if (m->m_pkthdr.len < sizeof(struct ip) + sizeof(struct mobhdr) -
sizeof(struct in_addr))
return (0);
ret = 0;
ME_RLOCK(sc);
if (ME_READY(sc)) {
ip = mtod(m, struct ip *);
if (sc->me_src.s_addr == ip->ip_dst.s_addr &&
sc->me_dst.s_addr == ip->ip_src.s_addr)
ret = 32 * 2;
}
ME_RUNLOCK(sc);
return (ret);
}
static int
me_set_tunnel(struct ifnet *ifp, struct sockaddr_in *src,
struct sockaddr_in *dst)
{
struct me_softc *sc, *tsc;
sx_assert(&me_ioctl_sx, SA_XLOCKED);
ME_LIST_LOCK();
sc = ifp->if_softc;
LIST_FOREACH(tsc, &V_me_softc_list, me_list) {
if (tsc == sc || !ME_READY(tsc))
continue;
if (tsc->me_src.s_addr == src->sin_addr.s_addr &&
tsc->me_dst.s_addr == dst->sin_addr.s_addr) {
ME_LIST_UNLOCK();
return (EADDRNOTAVAIL);
}
}
ME_LIST_UNLOCK();
ME_WLOCK(sc);
sc->me_dst = dst->sin_addr;
sc->me_src = src->sin_addr;
ME_WUNLOCK(sc);
if (sc->me_ecookie == NULL)
sc->me_ecookie = encap_attach_func(AF_INET, IPPROTO_MOBILE,
me_encapcheck, &in_mobile_protosw, sc);
if (sc->me_ecookie != NULL) {
ifp->if_drv_flags |= IFF_DRV_RUNNING;
if_link_state_change(ifp, LINK_STATE_UP);
}
return (0);
}
static void
me_delete_tunnel(struct ifnet *ifp)
{
struct me_softc *sc = ifp->if_softc;
sx_assert(&me_ioctl_sx, SA_XLOCKED);
if (sc->me_ecookie != NULL)
encap_detach(sc->me_ecookie);
sc->me_ecookie = NULL;
ME_WLOCK(sc);
sc->me_src.s_addr = 0;
sc->me_dst.s_addr = 0;
ME_WUNLOCK(sc);
ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
if_link_state_change(ifp, LINK_STATE_DOWN);
}
static uint16_t
me_in_cksum(uint16_t *p, int nwords)
{
uint32_t sum = 0;
while (nwords-- > 0)
sum += *p++;
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16);
return (~sum);
}
int
me_input(struct mbuf **mp, int *offp, int proto)
{
struct me_softc *sc;
struct mobhdr *mh;
struct ifnet *ifp;
struct mbuf *m;
struct ip *ip;
int hlen;
m = *mp;
sc = encap_getarg(m);
KASSERT(sc != NULL, ("encap_getarg returned NULL"));
ifp = ME2IFP(sc);
/* checks for short packets */
hlen = sizeof(struct mobhdr);
if (m->m_pkthdr.len < sizeof(struct ip) + hlen)
hlen -= sizeof(struct in_addr);
if (m->m_len < sizeof(struct ip) + hlen)
m = m_pullup(m, sizeof(struct ip) + hlen);
if (m == NULL)
goto drop;
mh = (struct mobhdr *)mtodo(m, sizeof(struct ip));
/* check for wrong flags */
if (mh->mob_flags & (~MOB_FLAGS_SP)) {
m_freem(m);
goto drop;
}
if (mh->mob_flags) {
if (hlen != sizeof(struct mobhdr)) {
m_freem(m);
goto drop;
}
} else
hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
/* check mobile header checksum */
if (me_in_cksum((uint16_t *)mh, hlen / sizeof(uint16_t)) != 0) {
m_freem(m);
goto drop;
}
#ifdef MAC
mac_ifnet_create_mbuf(ifp, m);
#endif
ip = mtod(m, struct ip *);
ip->ip_dst = mh->mob_dst;
ip->ip_p = mh->mob_proto;
ip->ip_sum = 0;
ip->ip_len = htons(m->m_pkthdr.len - hlen);
if (mh->mob_flags)
ip->ip_src = mh->mob_src;
memmove(mtodo(m, hlen), ip, sizeof(struct ip));
m_adj(m, hlen);
m_clrprotoflags(m);
m->m_pkthdr.rcvif = ifp;
m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
M_SETFIB(m, ifp->if_fib);
hlen = AF_INET;
BPF_MTAP2(ifp, &hlen, sizeof(hlen), 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(NETISR_IP, m);
return (IPPROTO_DONE);
drop:
if_inc_counter(ifp, IFCOUNTER_IERRORS, 1);
return (IPPROTO_DONE);
}
#define MTAG_ME 1414491977
static int
me_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_ME, 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_me_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_ME, 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
me_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 = me_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;
if (af != AF_INET) {
error = EAFNOSUPPORT;
goto drop;
}
BPF_MTAP2(ifp, &af, sizeof(af), m);
return (ifp->if_transmit(ifp, m));
drop:
m_freem(m);
if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
return (error);
}
static int
me_transmit(struct ifnet *ifp, struct mbuf *m)
{
ME_RLOCK_TRACKER;
struct mobhdr mh;
struct me_softc *sc;
struct ip *ip;
int error, hlen, plen;
sc = ifp->if_softc;
if (sc == NULL) {
error = ENETDOWN;
m_freem(m);
goto drop;
}
if (m->m_len < sizeof(struct ip))
m = m_pullup(m, sizeof(struct ip));
if (m == NULL) {
error = ENOBUFS;
goto drop;
}
ip = mtod(m, struct ip *);
/* Fragmented datagramms shouldn't be encapsulated */
if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
error = EINVAL;
m_freem(m);
goto drop;
}
mh.mob_proto = ip->ip_p;
mh.mob_src = ip->ip_src;
mh.mob_dst = ip->ip_dst;
ME_RLOCK(sc);
if (!ME_READY(sc)) {
ME_RUNLOCK(sc);
error = ENETDOWN;
m_freem(m);
goto drop;
}
if (in_hosteq(sc->me_src, ip->ip_src)) {
hlen = sizeof(struct mobhdr) - sizeof(struct in_addr);
mh.mob_flags = 0;
} else {
hlen = sizeof(struct mobhdr);
mh.mob_flags = MOB_FLAGS_SP;
}
plen = m->m_pkthdr.len;
ip->ip_src = sc->me_src;
ip->ip_dst = sc->me_dst;
M_SETFIB(m, sc->me_fibnum);
ME_RUNLOCK(sc);
M_PREPEND(m, hlen, M_NOWAIT);
if (m == NULL) {
error = ENOBUFS;
goto drop;
}
if (m->m_len < sizeof(struct ip) + hlen)
m = m_pullup(m, sizeof(struct ip) + hlen);
if (m == NULL) {
error = ENOBUFS;
goto drop;
}
memmove(mtod(m, void *), mtodo(m, hlen), sizeof(struct ip));
ip = mtod(m, struct ip *);
ip->ip_len = htons(m->m_pkthdr.len);
ip->ip_p = IPPROTO_MOBILE;
ip->ip_sum = 0;
mh.mob_csum = 0;
mh.mob_csum = me_in_cksum((uint16_t *)&mh, hlen / sizeof(uint16_t));
bcopy(&mh, mtodo(m, sizeof(struct ip)), hlen);
error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
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
me_qflush(struct ifnet *ifp __unused)
{
}
static int
memodevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
case MOD_UNLOAD:
break;
default:
return (EOPNOTSUPP);
}
return (0);
}
static moduledata_t me_mod = {
"if_me",
memodevent,
0
};
DECLARE_MODULE(if_me, me_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
MODULE_VERSION(if_me, 1);
