freebsd-dev/sys/net/if_tun.c
Brian Somers a48de39daf Close a race where we were releasing the unit resource at the start
of tunclose() rather than the end, and tunopen() grabbed that unit
before tunclose() finished (one process is allocating it while another
is freeing it!).

It may be worth hanging some sort of rw mutex around all specinfo
calls where d_close and the detach handler get a write lock and all
other functions get a read lock.  This would guarantee certain levels
of ``atomicity'' (is that a word?) that people may expect (I believe
Solaris does something like this).
2001-06-20 10:06:28 +00:00

823 lines
18 KiB
C

/* $NetBSD: if_tun.c,v 1.14 1994/06/29 06:36:25 cgd Exp $ */
/*
* Copyright (c) 1988, Julian Onions <jpo@cs.nott.ac.uk>
* Nottingham University 1987.
*
* This source may be freely distributed, however I would be interested
* in any changes that are made.
*
* This driver takes packets off the IP i/f and hands them up to a
* user process to have its wicked way with. This driver has it's
* roots in a similar driver written by Phil Cockcroft (formerly) at
* UCL. This driver is based much more on read/write/poll mode of
* operation though.
*
* $FreeBSD$
*/
#include "opt_inet.h"
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/socket.h>
#include <sys/filio.h>
#include <sys/sockio.h>
#include <sys/ttycom.h>
#include <sys/poll.h>
#include <sys/signalvar.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/conf.h>
#include <sys/uio.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <machine/bus.h> /* XXX Shouldn't really be required ! */
#include <sys/rman.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/route.h>
#include <net/intrq.h>
#ifdef INET
#include <netinet/in.h>
#endif
#include <net/bpf.h>
#include <net/if_tunvar.h>
#include <net/if_tun.h>
#define TUNDEBUG if (tundebug) printf
#define TUNNAME "tun"
#define TUN_MAXUNIT 0x7fff /* ifp->if_unit is only 15 bits */
static MALLOC_DEFINE(M_TUN, TUNNAME, "Tunnel Interface");
static int tundebug = 0;
static struct tun_softc *tunhead = NULL;
static struct rman tununits[1];
static udev_t tunbasedev = NOUDEV;
SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, "");
static void tunclone(void *arg, char *name, int namelen, dev_t *dev);
static void tuncreate(dev_t dev);
static int tunifioctl(struct ifnet *, u_long, caddr_t);
static int tuninit(struct ifnet *);
static int tunmodevent(module_t, int, void *);
static int tunoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
struct rtentry *rt);
static void tunstart(struct ifnet *);
static d_open_t tunopen;
static d_close_t tunclose;
static d_read_t tunread;
static d_write_t tunwrite;
static d_ioctl_t tunioctl;
static d_poll_t tunpoll;
#define CDEV_MAJOR 52
static struct cdevsw tun_cdevsw = {
/* open */ tunopen,
/* close */ tunclose,
/* read */ tunread,
/* write */ tunwrite,
/* ioctl */ tunioctl,
/* poll */ tunpoll,
/* mmap */ nommap,
/* strategy */ nostrategy,
/* name */ TUNNAME,
/* maj */ CDEV_MAJOR,
/* dump */ nodump,
/* psize */ nopsize,
/* flags */ 0,
};
static void
tunclone(void *arg, char *name, int namelen, dev_t *dev)
{
struct resource *r;
int err;
int u;
if (*dev != NODEV)
return;
if (strcmp(name, TUNNAME) == 0) {
r = rman_reserve_resource(tununits, 0, TUN_MAXUNIT, 1,
RF_ALLOCATED | RF_ACTIVE, NULL);
u = rman_get_start(r);
err = rman_release_resource(r);
KASSERT(err == 0, ("Unexpected failure releasing resource"));
*dev = makedev(CDEV_MAJOR, unit2minor(u));
if ((*dev)->si_flags & SI_NAMED)
return; /* Already make_dev()d */
} else if (dev_stdclone(name, NULL, TUNNAME, &u) != 1)
return; /* Don't recognise the name */
*dev = make_dev(&tun_cdevsw, unit2minor(u),
UID_ROOT, GID_WHEEL, 0600, "tun%d", u);
/*
* All devices depend on tunbasedev so that we can simply
* destroy_dev() this device at module unload time to get
* rid of all our make_dev()d resources.
*/
if (tunbasedev == NOUDEV)
tunbasedev = (*dev)->si_udev;
else {
(*dev)->si_flags |= SI_CHEAPCLONE;
dev_depends(udev2dev(tunbasedev, 0), *dev);
}
}
static int
tunmodevent(module_t mod, int type, void *data)
{
static eventhandler_tag tag;
struct tun_softc *tp;
dev_t dev;
int err;
switch (type) {
case MOD_LOAD:
tag = EVENTHANDLER_REGISTER(dev_clone, tunclone, 0, 1000);
if (tag == NULL)
return (ENOMEM);
if (!devfs_present) {
err = cdevsw_add(&tun_cdevsw);
if (err != 0) {
EVENTHANDLER_DEREGISTER(dev_clone, tag);
return (err);
}
}
tununits->rm_type = RMAN_ARRAY;
tununits->rm_descr = "open if_tun units";
err = rman_init(tununits);
if (err != 0) {
cdevsw_remove(&tun_cdevsw);
EVENTHANDLER_DEREGISTER(dev_clone, tag);
return (err);
}
err = rman_manage_region(tununits, 0, TUN_MAXUNIT);
if (err != 0) {
printf("%s: tununits: rman_manage_region: Failed %d\n",
TUNNAME, err);
rman_fini(tununits);
cdevsw_remove(&tun_cdevsw);
EVENTHANDLER_DEREGISTER(dev_clone, tag);
return (err);
}
break;
case MOD_UNLOAD:
err = rman_fini(tununits);
if (err != 0)
return (err);
EVENTHANDLER_DEREGISTER(dev_clone, tag);
while (tunhead != NULL) {
KASSERT((tunhead->tun_flags & TUN_OPEN) == 0,
("tununits is out of sync - unit %d",
tunhead->tun_if.if_unit));
tp = tunhead;
dev = makedev(tun_cdevsw.d_maj,
unit2minor(tp->tun_if.if_unit));
KASSERT(dev->si_drv1 == tp, ("Bad makedev result"));
tunhead = tp->next;
bpfdetach(&tp->tun_if);
if_detach(&tp->tun_if);
KASSERT(dev->si_flags & SI_NAMED, ("Missing make_dev"));
FREE(tp, M_TUN);
}
/*
* Destroying tunbasedev results in all of our make_dev()s
* conveniently going away.
*/
if (tunbasedev != NOUDEV)
destroy_dev(udev2dev(tunbasedev, 0));
if (!devfs_present)
cdevsw_remove(&tun_cdevsw);
break;
}
return 0;
}
static moduledata_t tun_mod = {
"if_tun",
tunmodevent,
0
};
DECLARE_MODULE(if_tun, tun_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
static void
tunstart(struct ifnet *ifp)
{
struct tun_softc *tp = ifp->if_softc;
if (tp->tun_flags & TUN_RWAIT) {
tp->tun_flags &= ~TUN_RWAIT;
wakeup((caddr_t)tp);
}
if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio)
pgsigio(tp->tun_sigio, SIGIO, 0);
selwakeup(&tp->tun_rsel);
}
static void
tuncreate(dev_t dev)
{
struct tun_softc *sc;
struct ifnet *ifp;
if (!(dev->si_flags & SI_NAMED))
dev = make_dev(&tun_cdevsw, minor(dev),
UID_UUCP, GID_DIALER, 0600, "tun%d", dev2unit(dev));
MALLOC(sc, struct tun_softc *, sizeof(*sc), M_TUN, M_WAITOK | M_ZERO);
sc->tun_flags = TUN_INITED;
sc->next = tunhead;
tunhead = sc;
ifp = &sc->tun_if;
ifp->if_unit = dev2unit(dev);
ifp->if_name = TUNNAME;
ifp->if_mtu = TUNMTU;
ifp->if_ioctl = tunifioctl;
ifp->if_output = tunoutput;
ifp->if_start = tunstart;
ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST;
ifp->if_type = IFT_PPP;
ifp->if_snd.ifq_maxlen = ifqmaxlen;
ifp->if_softc = sc;
if_attach(ifp);
bpfattach(ifp, DLT_NULL, sizeof(u_int));
dev->si_drv1 = sc;
}
static int
tunopen(dev_t dev, int flag, int mode, struct proc *p)
{
struct resource *r;
struct ifnet *ifp;
struct tun_softc *tp;
int unit;
unit = dev2unit(dev);
if (unit > TUN_MAXUNIT)
return (ENXIO);
r = rman_reserve_resource(tununits, unit, unit, 1,
RF_ALLOCATED | RF_ACTIVE, NULL);
if (r == NULL)
return (EBUSY);
dev->si_flags &= ~SI_CHEAPCLONE;
tp = dev->si_drv1;
if (!tp) {
tuncreate(dev);
tp = dev->si_drv1;
}
KASSERT(!(tp->tun_flags & TUN_OPEN), ("Resource & flags out-of-sync"));
tp->r_unit = r;
tp->tun_pid = p->p_pid;
ifp = &tp->tun_if;
tp->tun_flags |= TUN_OPEN;
TUNDEBUG("%s%d: open\n", ifp->if_name, ifp->if_unit);
return (0);
}
/*
* tunclose - close the device - mark i/f down & delete
* routing info
*/
static int
tunclose(dev_t dev, int foo, int bar, struct proc *p)
{
struct tun_softc *tp;
struct ifnet *ifp;
int s;
int err;
tp = dev->si_drv1;
ifp = &tp->tun_if;
KASSERT(tp->r_unit, ("Unit %d not marked open", ifp->if_unit));
tp->tun_flags &= ~TUN_OPEN;
tp->tun_pid = 0;
/*
* junk all pending output
*/
IF_DRAIN(&ifp->if_snd);
if (ifp->if_flags & IFF_UP) {
s = splimp();
if_down(ifp);
splx(s);
}
if (ifp->if_flags & IFF_RUNNING) {
register struct ifaddr *ifa;
s = splimp();
/* find internet addresses and delete routes */
TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link)
if (ifa->ifa_addr->sa_family == AF_INET)
rtinit(ifa, (int)RTM_DELETE,
tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0);
ifp->if_flags &= ~IFF_RUNNING;
splx(s);
}
funsetown(tp->tun_sigio);
selwakeup(&tp->tun_rsel);
TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit);
err = rman_release_resource(tp->r_unit);
KASSERT(err == 0, ("Unit %d failed to release", ifp->if_unit));
return (0);
}
static int
tuninit(struct ifnet *ifp)
{
struct tun_softc *tp = ifp->if_softc;
register struct ifaddr *ifa;
int error = 0;
TUNDEBUG("%s%d: tuninit\n", ifp->if_name, ifp->if_unit);
ifp->if_flags |= IFF_UP | IFF_RUNNING;
getmicrotime(&ifp->if_lastchange);
for (ifa = TAILQ_FIRST(&ifp->if_addrhead); ifa;
ifa = TAILQ_NEXT(ifa, ifa_link)) {
if (ifa->ifa_addr == NULL)
error = EFAULT;
/* XXX: Should maybe return straight off? */
else {
#ifdef INET
if (ifa->ifa_addr->sa_family == AF_INET) {
struct sockaddr_in *si;
si = (struct sockaddr_in *)ifa->ifa_addr;
if (si->sin_addr.s_addr)
tp->tun_flags |= TUN_IASET;
si = (struct sockaddr_in *)ifa->ifa_dstaddr;
if (si && si->sin_addr.s_addr)
tp->tun_flags |= TUN_DSTADDR;
}
#endif
}
}
return (error);
}
/*
* Process an ioctl request.
*/
int
tunifioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
struct ifreq *ifr = (struct ifreq *)data;
struct tun_softc *tp = ifp->if_softc;
struct ifstat *ifs;
int error = 0, s;
s = splimp();
switch(cmd) {
case SIOCGIFSTATUS:
ifs = (struct ifstat *)data;
if (tp->tun_pid)
sprintf(ifs->ascii + strlen(ifs->ascii),
"\tOpened by PID %d\n", tp->tun_pid);
break;
case SIOCSIFADDR:
error = tuninit(ifp);
TUNDEBUG("%s%d: address set, error=%d\n",
ifp->if_name, ifp->if_unit, error);
break;
case SIOCSIFDSTADDR:
error = tuninit(ifp);
TUNDEBUG("%s%d: destination address set, error=%d\n",
ifp->if_name, ifp->if_unit, error);
break;
case SIOCSIFMTU:
ifp->if_mtu = ifr->ifr_mtu;
TUNDEBUG("%s%d: mtu set\n", ifp->if_name, ifp->if_unit);
break;
case SIOCSIFFLAGS:
case SIOCADDMULTI:
case SIOCDELMULTI:
break;
default:
error = EINVAL;
}
splx(s);
return (error);
}
/*
* tunoutput - queue packets from higher level ready to put out.
*/
int
tunoutput(
struct ifnet *ifp,
struct mbuf *m0,
struct sockaddr *dst,
struct rtentry *rt)
{
struct tun_softc *tp = ifp->if_softc;
TUNDEBUG ("%s%d: tunoutput\n", ifp->if_name, ifp->if_unit);
if ((tp->tun_flags & TUN_READY) != TUN_READY) {
TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name,
ifp->if_unit, tp->tun_flags);
m_freem (m0);
return EHOSTDOWN;
}
/* BPF write needs to be handled specially */
if (dst->sa_family == AF_UNSPEC) {
dst->sa_family = *(mtod(m0, int *));
m0->m_len -= sizeof(int);
m0->m_pkthdr.len -= sizeof(int);
m0->m_data += sizeof(int);
}
if (ifp->if_bpf) {
/*
* 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 to it).
*/
struct mbuf m;
uint32_t af = dst->sa_family;
m.m_next = m0;
m.m_len = 4;
m.m_data = (char *)&af;
bpf_mtap(ifp, &m);
}
/* prepend sockaddr? this may abort if the mbuf allocation fails */
if (tp->tun_flags & TUN_LMODE) {
/* allocate space for sockaddr */
M_PREPEND(m0, dst->sa_len, M_DONTWAIT);
/* if allocation failed drop packet */
if (m0 == NULL) {
ifp->if_iqdrops++;
ifp->if_oerrors++;
return (ENOBUFS);
} else {
bcopy(dst, m0->m_data, dst->sa_len);
}
}
if (tp->tun_flags & TUN_IFHEAD) {
/* Prepend the address family */
M_PREPEND(m0, 4, M_DONTWAIT);
/* if allocation failed drop packet */
if (m0 == NULL) {
ifp->if_iqdrops++;
ifp->if_oerrors++;
return ENOBUFS;
} else
*(u_int32_t *)m0->m_data = htonl(dst->sa_family);
} else {
#ifdef INET
if (dst->sa_family != AF_INET)
#endif
{
m_freem(m0);
return EAFNOSUPPORT;
}
}
if (! IF_HANDOFF(&ifp->if_snd, m0, ifp)) {
ifp->if_collisions++;
return ENOBUFS;
}
ifp->if_opackets++;
return 0;
}
/*
* the cdevsw interface is now pretty minimal.
*/
static int
tunioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
{
int s;
int error;
struct tun_softc *tp = dev->si_drv1;
struct tuninfo *tunp;
switch (cmd) {
case TUNSIFINFO:
tunp = (struct tuninfo *)data;
if (tunp->mtu < IF_MINMTU)
return (EINVAL);
if (tp->tun_if.if_mtu != tunp->mtu && (error = suser(p)) != 0)
return (error);
tp->tun_if.if_mtu = tunp->mtu;
tp->tun_if.if_type = tunp->type;
tp->tun_if.if_baudrate = tunp->baudrate;
break;
case TUNGIFINFO:
tunp = (struct tuninfo *)data;
tunp->mtu = tp->tun_if.if_mtu;
tunp->type = tp->tun_if.if_type;
tunp->baudrate = tp->tun_if.if_baudrate;
break;
case TUNSDEBUG:
tundebug = *(int *)data;
break;
case TUNGDEBUG:
*(int *)data = tundebug;
break;
case TUNSLMODE:
if (*(int *)data) {
tp->tun_flags |= TUN_LMODE;
tp->tun_flags &= ~TUN_IFHEAD;
} else
tp->tun_flags &= ~TUN_LMODE;
break;
case TUNSIFHEAD:
if (*(int *)data) {
tp->tun_flags |= TUN_IFHEAD;
tp->tun_flags &= ~TUN_LMODE;
} else
tp->tun_flags &= ~TUN_IFHEAD;
break;
case TUNGIFHEAD:
*(int *)data = (tp->tun_flags & TUN_IFHEAD) ? 1 : 0;
break;
case TUNSIFMODE:
/* deny this if UP */
if (tp->tun_if.if_flags & IFF_UP)
return(EBUSY);
switch (*(int *)data) {
case IFF_POINTOPOINT:
tp->tun_if.if_flags |= IFF_POINTOPOINT;
tp->tun_if.if_flags &= ~IFF_BROADCAST;
break;
case IFF_BROADCAST:
tp->tun_if.if_flags &= ~IFF_POINTOPOINT;
tp->tun_if.if_flags |= IFF_BROADCAST;
break;
default:
return(EINVAL);
}
break;
case TUNSIFPID:
tp->tun_pid = curproc->p_pid;
break;
case FIONBIO:
break;
case FIOASYNC:
if (*(int *)data)
tp->tun_flags |= TUN_ASYNC;
else
tp->tun_flags &= ~TUN_ASYNC;
break;
case FIONREAD:
s = splimp();
if (tp->tun_if.if_snd.ifq_head) {
struct mbuf *mb = tp->tun_if.if_snd.ifq_head;
for( *(int *)data = 0; mb != 0; mb = mb->m_next)
*(int *)data += mb->m_len;
} else
*(int *)data = 0;
splx(s);
break;
case FIOSETOWN:
return (fsetown(*(int *)data, &tp->tun_sigio));
case FIOGETOWN:
*(int *)data = fgetown(tp->tun_sigio);
return (0);
/* This is deprecated, FIOSETOWN should be used instead. */
case TIOCSPGRP:
return (fsetown(-(*(int *)data), &tp->tun_sigio));
/* This is deprecated, FIOGETOWN should be used instead. */
case TIOCGPGRP:
*(int *)data = -fgetown(tp->tun_sigio);
return (0);
default:
return (ENOTTY);
}
return (0);
}
/*
* The cdevsw read interface - reads a packet at a time, or at
* least as much of a packet as can be read.
*/
static int
tunread(dev_t dev, struct uio *uio, int flag)
{
struct tun_softc *tp = dev->si_drv1;
struct ifnet *ifp = &tp->tun_if;
struct mbuf *m, *m0;
int error=0, len, s;
TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit);
if ((tp->tun_flags & TUN_READY) != TUN_READY) {
TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name,
ifp->if_unit, tp->tun_flags);
return EHOSTDOWN;
}
tp->tun_flags &= ~TUN_RWAIT;
s = splimp();
do {
IF_DEQUEUE(&ifp->if_snd, m0);
if (m0 == 0) {
if (flag & IO_NDELAY) {
splx(s);
return EWOULDBLOCK;
}
tp->tun_flags |= TUN_RWAIT;
if((error = tsleep((caddr_t)tp, PCATCH | (PZERO + 1),
"tunread", 0)) != 0) {
splx(s);
return error;
}
}
} while (m0 == 0);
splx(s);
while (m0 && uio->uio_resid > 0 && error == 0) {
len = min(uio->uio_resid, m0->m_len);
if (len == 0)
break;
error = uiomove(mtod(m0, caddr_t), len, uio);
MFREE(m0, m);
m0 = m;
}
if (m0) {
TUNDEBUG("Dropping mbuf\n");
m_freem(m0);
}
return error;
}
/*
* the cdevsw write interface - an atomic write is a packet - or else!
*/
static int
tunwrite(dev_t dev, struct uio *uio, int flag)
{
struct tun_softc *tp = dev->si_drv1;
struct ifnet *ifp = &tp->tun_if;
struct mbuf *top, **mp, *m;
int error=0, tlen, mlen;
uint32_t family;
TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit);
if (uio->uio_resid == 0)
return 0;
if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) {
TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit,
uio->uio_resid);
return EIO;
}
tlen = uio->uio_resid;
/* get a header mbuf */
MGETHDR(m, M_DONTWAIT, MT_DATA);
if (m == NULL)
return ENOBUFS;
mlen = MHLEN;
top = 0;
mp = &top;
while (error == 0 && uio->uio_resid > 0) {
m->m_len = min(mlen, uio->uio_resid);
error = uiomove(mtod (m, caddr_t), m->m_len, uio);
*mp = m;
mp = &m->m_next;
if (uio->uio_resid > 0) {
MGET (m, M_DONTWAIT, MT_DATA);
if (m == 0) {
error = ENOBUFS;
break;
}
mlen = MLEN;
}
}
if (error) {
if (top)
m_freem (top);
ifp->if_ierrors++;
return error;
}
top->m_pkthdr.len = tlen;
top->m_pkthdr.rcvif = ifp;
if (ifp->if_bpf) {
if (tp->tun_flags & TUN_IFHEAD) {
/*
* Conveniently, we already have a 4-byte address
* family prepended to our packet !
* Inconveniently, it's in the wrong byte order !
*/
if ((top = m_pullup(top, sizeof(family))) == NULL)
return ENOBUFS;
*mtod(top, u_int32_t *) =
ntohl(*mtod(top, u_int32_t *));
bpf_mtap(ifp, top);
*mtod(top, u_int32_t *) =
htonl(*mtod(top, u_int32_t *));
} else {
/*
* 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 to it).
*/
struct mbuf m;
uint32_t af = AF_INET;
m.m_next = top;
m.m_len = 4;
m.m_data = (char *)&af;
bpf_mtap(ifp, &m);
}
}
if (tp->tun_flags & TUN_IFHEAD) {
if (top->m_len < sizeof(family) &&
(top = m_pullup(top, sizeof(family))) == NULL)
return ENOBUFS;
family = ntohl(*mtod(top, u_int32_t *));
m_adj(top, sizeof(family));
} else
family = AF_INET;
ifp->if_ibytes += top->m_pkthdr.len;
ifp->if_ipackets++;
return family_enqueue(family, top);
}
/*
* tunpoll - the poll interface, this is only useful on reads
* really. The write detect always returns true, write never blocks
* anyway, it either accepts the packet or drops it.
*/
static int
tunpoll(dev_t dev, int events, struct proc *p)
{
int s;
struct tun_softc *tp = dev->si_drv1;
struct ifnet *ifp = &tp->tun_if;
int revents = 0;
s = splimp();
TUNDEBUG("%s%d: tunpoll\n", ifp->if_name, ifp->if_unit);
if (events & (POLLIN | POLLRDNORM)) {
if (ifp->if_snd.ifq_len > 0) {
TUNDEBUG("%s%d: tunpoll q=%d\n", ifp->if_name,
ifp->if_unit, ifp->if_snd.ifq_len);
revents |= events & (POLLIN | POLLRDNORM);
} else {
TUNDEBUG("%s%d: tunpoll waiting\n", ifp->if_name,
ifp->if_unit);
selrecord(p, &tp->tun_rsel);
}
}
if (events & (POLLOUT | POLLWRNORM))
revents |= events & (POLLOUT | POLLWRNORM);
splx(s);
return (revents);
}