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|
/* $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_atalk.h"
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_ipx.h"
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/mac.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/socket.h>
#include <sys/fcntl.h>
#include <sys/filio.h>
#include <sys/sockio.h>
#include <sys/ttycom.h>
#include <sys/poll.h>
#include <sys/selinfo.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/malloc.h>
#include <sys/random.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/netisr.h>
#include <net/route.h>
#ifdef INET
#include <netinet/in.h>
#endif
#include <net/bpf.h>
#include <net/if_tun.h>
#include <sys/queue.h>
/*
* tun_list is protected by global tunmtx. Other mutable fields are
* protected by tun->tun_mtx, or by their owning subsystem. tun_dev is
* static for the duration of a tunnel interface.
*/
struct tun_softc {
TAILQ_ENTRY(tun_softc) tun_list;
struct cdev *tun_dev;
u_short tun_flags; /* misc flags */
#define TUN_OPEN 0x0001
#define TUN_INITED 0x0002
#define TUN_RCOLL 0x0004
#define TUN_IASET 0x0008
#define TUN_DSTADDR 0x0010
#define TUN_LMODE 0x0020
#define TUN_RWAIT 0x0040
#define TUN_ASYNC 0x0080
#define TUN_IFHEAD 0x0100
#define TUN_READY (TUN_OPEN | TUN_INITED)
/*
* XXXRW: tun_pid is used to exclusively lock /dev/tun. Is this
* actually needed? Can we just return EBUSY if already open?
* Problem is that this involved inherent races when a tun device
* is handed off from one process to another, as opposed to just
* being slightly stale informationally.
*/
pid_t tun_pid; /* owning pid */
struct ifnet tun_if; /* the interface */
struct sigio *tun_sigio; /* information for async I/O */
struct selinfo tun_rsel; /* read select */
struct mtx tun_mtx; /* protect mutable softc fields */
};
#define TUNDEBUG if (tundebug) if_printf
#define TUNNAME "tun"
/*
* All mutable global variables in if_tun are locked using tunmtx, with
* the exception of tundebug, which is used unlocked, and tunclones,
* which is static after setup.
*/
static struct mtx tunmtx;
static MALLOC_DEFINE(M_TUN, TUNNAME, "Tunnel Interface");
static int tundebug = 0;
static struct clonedevs *tunclones;
static TAILQ_HEAD(,tun_softc) tunhead = TAILQ_HEAD_INITIALIZER(tunhead);
SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, "");
static void tunclone(void *arg, char *name, int namelen, struct cdev **dev);
static void tuncreate(struct cdev *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;
static struct cdevsw tun_cdevsw = {
.d_version = D_VERSION,
.d_flags = D_PSEUDO | D_NEEDGIANT,
.d_open = tunopen,
.d_close = tunclose,
.d_read = tunread,
.d_write = tunwrite,
.d_ioctl = tunioctl,
.d_poll = tunpoll,
.d_name = TUNNAME,
};
static void
tunclone(void *arg, char *name, int namelen, struct cdev **dev)
{
int u, i;
if (*dev != NULL)
return;
if (strcmp(name, TUNNAME) == 0) {
u = -1;
} else if (dev_stdclone(name, NULL, TUNNAME, &u) != 1)
return; /* Don't recognise the name */
if (u != -1 && u > IF_MAXUNIT)
return; /* Unit number too high */
/* find any existing device, or allocate new unit number */
i = clone_create(&tunclones, &tun_cdevsw, &u, dev, 0);
if (i) {
/* No preexisting struct cdev *, create one */
*dev = make_dev(&tun_cdevsw, unit2minor(u),
UID_UUCP, GID_DIALER, 0600, "tun%d", u);
if (*dev != NULL) {
dev_ref(*dev);
(*dev)->si_flags |= SI_CHEAPCLONE;
}
}
}
static void
tun_destroy(struct tun_softc *tp)
{
struct cdev *dev;
/* Unlocked read. */
KASSERT((tp->tun_flags & TUN_OPEN) == 0,
("tununits is out of sync - unit %d", tp->tun_if.if_dunit));
dev = tp->tun_dev;
bpfdetach(&tp->tun_if);
if_detach(&tp->tun_if);
destroy_dev(dev);
mtx_destroy(&tp->tun_mtx);
free(tp, M_TUN);
}
static int
tunmodevent(module_t mod, int type, void *data)
{
static eventhandler_tag tag;
struct tun_softc *tp;
switch (type) {
case MOD_LOAD:
mtx_init(&tunmtx, "tunmtx", NULL, MTX_DEF);
clone_setup(&tunclones);
tag = EVENTHANDLER_REGISTER(dev_clone, tunclone, 0, 1000);
if (tag == NULL)
return (ENOMEM);
break;
case MOD_UNLOAD:
EVENTHANDLER_DEREGISTER(dev_clone, tag);
mtx_lock(&tunmtx);
while ((tp = TAILQ_FIRST(&tunhead)) != NULL) {
TAILQ_REMOVE(&tunhead, tp, tun_list);
mtx_unlock(&tunmtx);
tun_destroy(tp);
mtx_lock(&tunmtx);
}
mtx_unlock(&tunmtx);
clone_cleanup(&tunclones);
mtx_destroy(&tunmtx);
break;
default:
return EOPNOTSUPP;
}
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;
struct mbuf *m;
if (ALTQ_IS_ENABLED(&ifp->if_snd)) {
IFQ_LOCK(&ifp->if_snd);
IFQ_POLL_NOLOCK(&ifp->if_snd, m);
if (m == NULL) {
IFQ_UNLOCK(&ifp->if_snd);
return;
}
IFQ_UNLOCK(&ifp->if_snd);
}
mtx_lock(&tp->tun_mtx);
if (tp->tun_flags & TUN_RWAIT) {
tp->tun_flags &= ~TUN_RWAIT;
wakeup(tp);
}
if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio) {
mtx_unlock(&tp->tun_mtx);
pgsigio(&tp->tun_sigio, SIGIO, 0);
} else
mtx_unlock(&tp->tun_mtx);
selwakeuppri(&tp->tun_rsel, PZERO + 1);
}
static void
tuncreate(struct cdev *dev)
{
struct tun_softc *sc;
struct ifnet *ifp;
dev->si_flags &= ~SI_CHEAPCLONE;
MALLOC(sc, struct tun_softc *, sizeof(*sc), M_TUN, M_WAITOK | M_ZERO);
mtx_init(&sc->tun_mtx, "tun_mtx", NULL, MTX_DEF);
sc->tun_flags = TUN_INITED;
sc->tun_dev = dev;
mtx_lock(&tunmtx);
TAILQ_INSERT_TAIL(&tunhead, sc, tun_list);
mtx_unlock(&tunmtx);
ifp = &sc->tun_if;
if_initname(ifp, TUNNAME, dev2unit(dev));
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_softc = sc;
IFQ_SET_MAXLEN(&ifp->if_snd, ifqmaxlen);
ifp->if_snd.ifq_drv_maxlen = 0;
IFQ_SET_READY(&ifp->if_snd);
if_attach(ifp);
bpfattach(ifp, DLT_NULL, sizeof(u_int));
dev->si_drv1 = sc;
}
static int
tunopen(struct cdev *dev, int flag, int mode, struct thread *td)
{
struct ifnet *ifp;
struct tun_softc *tp;
/*
* XXXRW: Non-atomic test and set of dev->si_drv1 requires
* synchronization.
*/
tp = dev->si_drv1;
if (!tp) {
tuncreate(dev);
tp = dev->si_drv1;
}
/*
* XXXRW: This use of tun_pid is subject to error due to the
* fact that a reference to the tunnel can live beyond the
* death of the process that created it. Can we replace this
* with a simple busy flag?
*/
mtx_lock(&tp->tun_mtx);
if (tp->tun_pid != 0 && tp->tun_pid != td->td_proc->p_pid) {
mtx_unlock(&tp->tun_mtx);
return (EBUSY);
}
tp->tun_pid = td->td_proc->p_pid;
tp->tun_flags |= TUN_OPEN;
mtx_unlock(&tp->tun_mtx);
ifp = &tp->tun_if;
TUNDEBUG(ifp, "open\n");
return (0);
}
/*
* tunclose - close the device - mark i/f down & delete
* routing info
*/
static int
tunclose(struct cdev *dev, int foo, int bar, struct thread *td)
{
struct tun_softc *tp;
struct ifnet *ifp;
int s;
tp = dev->si_drv1;
ifp = &tp->tun_if;
mtx_lock(&tp->tun_mtx);
tp->tun_flags &= ~TUN_OPEN;
tp->tun_pid = 0;
/*
* junk all pending output
*/
s = splimp();
IFQ_PURGE(&ifp->if_snd);
splx(s);
mtx_unlock(&tp->tun_mtx);
if (ifp->if_flags & IFF_UP) {
s = splimp();
if_down(ifp);
splx(s);
}
if (ifp->if_flags & IFF_RUNNING) {
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)
/* Unlocked read. */
rtinit(ifa, (int)RTM_DELETE,
tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0);
ifp->if_flags &= ~IFF_RUNNING;
splx(s);
}
funsetown(&tp->tun_sigio);
selwakeuppri(&tp->tun_rsel, PZERO + 1);
TUNDEBUG (ifp, "closed\n");
return (0);
}
static int
tuninit(struct ifnet *ifp)
{
struct tun_softc *tp = ifp->if_softc;
struct ifaddr *ifa;
int error = 0;
TUNDEBUG(ifp, "tuninit\n");
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;
mtx_lock(&tp->tun_mtx);
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;
mtx_unlock(&tp->tun_mtx);
}
#endif
}
}
return (error);
}
/*
* Process an ioctl request.
*/
static 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;
mtx_lock(&tp->tun_mtx);
if (tp->tun_pid)
sprintf(ifs->ascii + strlen(ifs->ascii),
"\tOpened by PID %d\n", tp->tun_pid);
mtx_unlock(&tp->tun_mtx);
break;
case SIOCSIFADDR:
error = tuninit(ifp);
TUNDEBUG(ifp, "address set, error=%d\n", error);
break;
case SIOCSIFDSTADDR:
error = tuninit(ifp);
TUNDEBUG(ifp, "destination address set, error=%d\n", error);
break;
case SIOCSIFMTU:
ifp->if_mtu = ifr->ifr_mtu;
TUNDEBUG(ifp, "mtu set\n");
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.
*/
static int
tunoutput(
struct ifnet *ifp,
struct mbuf *m0,
struct sockaddr *dst,
struct rtentry *rt)
{
struct tun_softc *tp = ifp->if_softc;
u_short cached_tun_flags;
int error;
TUNDEBUG (ifp, "tunoutput\n");
#ifdef MAC
error = mac_check_ifnet_transmit(ifp, m0);
if (error) {
m_freem(m0);
return (error);
}
#endif
/* Could be unlocked read? */
mtx_lock(&tp->tun_mtx);
cached_tun_flags = tp->tun_flags;
mtx_unlock(&tp->tun_mtx);
if ((cached_tun_flags & TUN_READY) != TUN_READY) {
TUNDEBUG (ifp, "not ready 0%o\n", tp->tun_flags);
m_freem (m0);
return (EHOSTDOWN);
}
if ((ifp->if_flags & IFF_UP) != IFF_UP) {
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) {
uint32_t af = dst->sa_family;
bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m0);
}
/* prepend sockaddr? this may abort if the mbuf allocation fails */
if (cached_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 (cached_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);
}
}
IFQ_HANDOFF(ifp, m0, error);
if (error) {
ifp->if_collisions++;
return (ENOBUFS);
}
ifp->if_opackets++;
return (0);
}
/*
* the cdevsw interface is now pretty minimal.
*/
static int
tunioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *td)
{
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(td)) != 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:
mtx_lock(&tp->tun_mtx);
if (*(int *)data) {
tp->tun_flags |= TUN_LMODE;
tp->tun_flags &= ~TUN_IFHEAD;
} else
tp->tun_flags &= ~TUN_LMODE;
mtx_unlock(&tp->tun_mtx);
break;
case TUNSIFHEAD:
mtx_lock(&tp->tun_mtx);
if (*(int *)data) {
tp->tun_flags |= TUN_IFHEAD;
tp->tun_flags &= ~TUN_LMODE;
} else
tp->tun_flags &= ~TUN_IFHEAD;
mtx_unlock(&tp->tun_mtx);
break;
case TUNGIFHEAD:
/* Could be unlocked read? */
mtx_lock(&tp->tun_mtx);
*(int *)data = (tp->tun_flags & TUN_IFHEAD) ? 1 : 0;
mtx_unlock(&tp->tun_mtx);
break;
case TUNSIFMODE:
/* deny this if UP */
if (tp->tun_if.if_flags & IFF_UP)
return(EBUSY);
switch (*(int *)data & ~IFF_MULTICAST) {
case IFF_POINTOPOINT:
case IFF_BROADCAST:
tp->tun_if.if_flags &=
~(IFF_BROADCAST|IFF_POINTOPOINT|IFF_MULTICAST);
tp->tun_if.if_flags |= *(int *)data;
break;
default:
return(EINVAL);
}
break;
case TUNSIFPID:
mtx_lock(&tp->tun_mtx);
tp->tun_pid = curthread->td_proc->p_pid;
mtx_unlock(&tp->tun_mtx);
break;
case FIONBIO:
break;
case FIOASYNC:
mtx_lock(&tp->tun_mtx);
if (*(int *)data)
tp->tun_flags |= TUN_ASYNC;
else
tp->tun_flags &= ~TUN_ASYNC;
mtx_unlock(&tp->tun_mtx);
break;
case FIONREAD:
s = splimp();
if (!IFQ_IS_EMPTY(&tp->tun_if.if_snd)) {
struct mbuf *mb;
IFQ_LOCK(&tp->tun_if.if_snd);
IFQ_POLL_NOLOCK(&tp->tun_if.if_snd, mb);
for( *(int *)data = 0; mb != 0; mb = mb->m_next)
*(int *)data += mb->m_len;
IFQ_UNLOCK(&tp->tun_if.if_snd);
} 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(struct cdev *dev, struct uio *uio, int flag)
{
struct tun_softc *tp = dev->si_drv1;
struct ifnet *ifp = &tp->tun_if;
struct mbuf *m;
int error=0, len, s;
TUNDEBUG (ifp, "read\n");
mtx_lock(&tp->tun_mtx);
if ((tp->tun_flags & TUN_READY) != TUN_READY) {
mtx_unlock(&tp->tun_mtx);
TUNDEBUG (ifp, "not ready 0%o\n", tp->tun_flags);
return (EHOSTDOWN);
}
tp->tun_flags &= ~TUN_RWAIT;
mtx_unlock(&tp->tun_mtx);
s = splimp();
do {
IFQ_DEQUEUE(&ifp->if_snd, m);
if (m == NULL) {
if (flag & O_NONBLOCK) {
splx(s);
return (EWOULDBLOCK);
}
mtx_lock(&tp->tun_mtx);
tp->tun_flags |= TUN_RWAIT;
mtx_unlock(&tp->tun_mtx);
if((error = tsleep(tp, PCATCH | (PZERO + 1),
"tunread", 0)) != 0) {
splx(s);
return (error);
}
}
} while (m == NULL);
splx(s);
while (m && uio->uio_resid > 0 && error == 0) {
len = min(uio->uio_resid, m->m_len);
if (len != 0)
error = uiomove(mtod(m, void *), len, uio);
m = m_free(m);
}
if (m) {
TUNDEBUG(ifp, "Dropping mbuf\n");
m_freem(m);
}
return (error);
}
/*
* the cdevsw write interface - an atomic write is a packet - or else!
*/
static int
tunwrite(struct cdev *dev, struct uio *uio, int flag)
{
struct tun_softc *tp = dev->si_drv1;
struct ifnet *ifp = &tp->tun_if;
struct mbuf *m;
int error = 0;
uint32_t family;
int isr;
TUNDEBUG(ifp, "tunwrite\n");
if ((ifp->if_flags & IFF_UP) != IFF_UP)
/* ignore silently */
return (0);
if (uio->uio_resid == 0)
return (0);
if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) {
TUNDEBUG(ifp, "len=%d!\n", uio->uio_resid);
return (EIO);
}
if ((m = m_uiotombuf(uio, M_DONTWAIT, 0)) == NULL) {
ifp->if_ierrors++;
return (error);
}
m->m_pkthdr.rcvif = ifp;
#ifdef MAC
mac_create_mbuf_from_ifnet(ifp, m);
#endif
/* Could be unlocked read? */
mtx_lock(&tp->tun_mtx);
if (tp->tun_flags & TUN_IFHEAD) {
mtx_unlock(&tp->tun_mtx);
if (m->m_len < sizeof(family) &&
(m = m_pullup(m, sizeof(family))) == NULL)
return (ENOBUFS);
family = ntohl(*mtod(m, u_int32_t *));
m_adj(m, sizeof(family));
} else {
mtx_unlock(&tp->tun_mtx);
family = AF_INET;
}
BPF_MTAP2(ifp, &family, sizeof(family), m);
switch (family) {
#ifdef INET
case AF_INET:
isr = NETISR_IP;
break;
#endif
#ifdef INET6
case AF_INET6:
isr = NETISR_IPV6;
break;
#endif
#ifdef IPX
case AF_IPX:
isr = NETISR_IPX;
break;
#endif
#ifdef NETATALK
case AF_APPLETALK:
isr = NETISR_ATALK2;
break;
#endif
default:
m_freem(m);
return (EAFNOSUPPORT);
}
/* First chunk of an mbuf contains good junk */
if (harvest.point_to_point)
random_harvest(m, 16, 3, 0, RANDOM_NET);
ifp->if_ibytes += m->m_pkthdr.len;
ifp->if_ipackets++;
netisr_dispatch(isr, m);
return (0);
}
/*
* 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(struct cdev *dev, int events, struct thread *td)
{
int s;
struct tun_softc *tp = dev->si_drv1;
struct ifnet *ifp = &tp->tun_if;
int revents = 0;
struct mbuf *m;
s = splimp();
TUNDEBUG(ifp, "tunpoll\n");
if (events & (POLLIN | POLLRDNORM)) {
IFQ_LOCK(&ifp->if_snd);
IFQ_POLL_NOLOCK(&ifp->if_snd, m);
if (m != NULL) {
TUNDEBUG(ifp, "tunpoll q=%d\n", ifp->if_snd.ifq_len);
revents |= events & (POLLIN | POLLRDNORM);
} else {
TUNDEBUG(ifp, "tunpoll waiting\n");
selrecord(td, &tp->tun_rsel);
}
IFQ_UNLOCK(&ifp->if_snd);
}
if (events & (POLLOUT | POLLWRNORM))
revents |= events & (POLLOUT | POLLWRNORM);
splx(s);
return (revents);
}
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