D22691.id65557.diff
No OneTemporary
Actions

Size

16 KB

Referenced Files

None

Subscribers

None

D22691.id65557.diff
View Options

	Index: sys/net/if.h
	===================================================================
	--- sys/net/if.h
	+++ sys/net/if.h
	@@ -160,9 +160,11 @@
	#define IFF_PPROMISC 0x20000 /* (n) user-requested promisc mode */
	#define IFF_MONITOR 0x40000 /* (n) user-requested monitor mode */
	#define IFF_STATICARP 0x80000 /* (n) static ARP */
	+#define IFF_DETACHING 0x100000 /* (n) interface is detaching */
	#define IFF_DYING 0x200000 /* (n) interface is winding down */
	#define IFF_RENAMING 0x400000 /* (n) interface is being renamed */
	#define IFF_NOGROUP 0x800000 /* (n) interface is not part of any groups */
	+#define IFF_VMOVING 0x1000000 /* (n) interface is changing vnets */


	/*
	Index: sys/net/if.c
	===================================================================
	--- sys/net/if.c
	+++ sys/net/if.c
	@@ -262,6 +262,9 @@
	static void if_input_default(struct ifnet , struct mbuf );
	static int if_requestencap_default(struct ifnet , struct if_encap_req );
	static void if_route(struct ifnet *, int flag, int fam);
	+static bool if_busy(struct ifnet *ifp, int setflags);
	+static void if_unbusy(struct ifnet *ifp);
	+static void if_busy_wait(struct ifnet *ifp);
	static int if_setflag(struct ifnet , int, int, int , int);
	static int if_transmit(struct ifnet ifp, struct mbuf m);
	static void if_unroute(struct ifnet *, int flag, int fam);
	@@ -274,6 +277,7 @@
	static int if_detach_internal(struct ifnet , int, struct if_clone *);
	static void if_siocaddmulti(void *, int);
	#ifdef VIMAGE
	+static int if_vmove_busied(struct ifnet , struct vnet );
	static int if_vmove(struct ifnet , struct vnet );
	#endif

	@@ -471,10 +475,60 @@
	{
	struct ifnet ifp, nifp;

	+ /*
	+ * We do a two pass approach here: first, we go through and busy up all
	+ * of the interfaces with the ifnet writelock held. This ensures the
	+ * list is stable while we determine what still needs to be detached and
	+ * busy up the rest. Any that are already attempting to if_detach()
	+ * will have been properly marked IFF_DETACHING, and we'll skip over
	+ * them here.
	+ */
	+ IFNET_WLOCK();
	+ CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
	+ if (ifp->if_home_vnet == ifp->if_vnet)
	+ continue;
	+ IF_BUSY_LOCK(ifp);
	+ if ((ifp->if_flags & IFF_DETACHING) == 0) {
	+ /*
	+ * If the interface needs to be moved back to the parent
	+ * vnet and it's not already in the process of
	+ * detaching, go ahead and busy it and mark it as such.
	+ *
	+ * This guarantees that the interface can't be destroyed
	+ * or moved while we're in the process of tearing down
	+ * the vnet. If it's already detaching, then it will be
	+ * a non-issue as it has to be leaving the vnet and we
	+ * can assume it will be gone in due time.
	+ */
	+ refcount_acquire(&ifp->if_busy_count);
	+ ifp->if_flags \|= IFF_DETACHING \| IFF_VMOVING;
	+ }
	+ IF_BUSY_UNLOCK(ifp);
	+ }
	+ IFNET_WUNLOCK();
	/* Return all inherited interfaces to their parent vnets. */
	CK_STAILQ_FOREACH_SAFE(ifp, &V_ifnet, if_link, nifp) {
	- if (ifp->if_home_vnet != ifp->if_vnet)
	- if_vmove(ifp, ifp->if_home_vnet);
	+ if (ifp->if_home_vnet == ifp->if_vnet)
	+ continue;
	+ /*
	+ * At this point, we have two possible scenarios for every ifnet
	+ * still here that needs re-homed: either we're re-homing it
	+ * because we marked it as such above, or someone else is
	+ * removing it. If we're re-homing it, IFF_VMOVING should
	+ * still be set from up above. If someone else is trying to
	+ * remove it, then they've unset IFF_VMOVING and are waiting for
	+ * us to drop the refcount. In that scenario, we don't need to
	+ * bother with an if_vmove() because the waiter is simply going
	+ * to drop it as soon as we let go of the reference.
	+ */
	+ IF_BUSY_LOCK(ifp);
	+ if ((ifp->if_flags & IFF_VMOVING) != 0) {
	+ IF_BUSY_UNLOCK(ifp);
	+ if_vmove_busied(ifp, ifp->if_home_vnet);
	+ } else {
	+ IF_BUSY_UNLOCK(ifp);
	+ }
	+ if_unbusy(ifp);
	}
	}
	/*
	@@ -561,6 +615,7 @@
	}

	IF_ADDR_LOCK_INIT(ifp);
	+ IF_BUSY_LOCK_INIT(ifp);
	TASK_INIT(&ifp->if_linktask, 0, do_link_state_change, ifp);
	TASK_INIT(&ifp->if_addmultitask, 0, if_siocaddmulti, ifp);
	ifp->if_afdata_initialized = 0;
	@@ -607,7 +662,7 @@
	if_free_internal(struct ifnet *ifp)
	{

	- KASSERT((ifp->if_flags & IFF_DYING),
	+ KASSERT((ifp->if_flags & IFF_DYING) && (ifp->if_flags & IFF_DETACHING),
	("if_free_internal: interface not dying"));

	if (if_com_free[ifp->if_alloctype] != NULL)
	@@ -619,6 +674,7 @@
	#endif /* MAC */
	IF_AFDATA_DESTROY(ifp);
	IF_ADDR_LOCK_DESTROY(ifp);
	+ IF_BUSY_LOCK_DESTROY(ifp);
	ifq_delete(&ifp->if_snd);

	for (int i = 0; i < IFCOUNTERS; i++)
	@@ -1058,6 +1114,22 @@
	if_detach(struct ifnet *ifp)
	{

	+ /*
	+ * Grab the ifnet writelock as well as the interface busy lock here to
	+ * serialize parts of vnet shutdown with interface detach. If we win
	+ * here over vnet_sysuninit_shutdown, then we'll proceed to detach and
	+ * vnet_shutdown will be properly set before we do something we regret.
	+ * If we lose here, the interface will be busy'd as it gets removed from
	+ * the vnet and then we'll swoop in and finish the process.
	+ */
	+ IFNET_WLOCK();
	+ IF_BUSY_LOCK(ifp);
	+ ifp->if_flags \|= IFF_DETACHING;
	+ ifp->if_flags &= ~IFF_VMOVING;
	+ IF_BUSY_UNLOCK(ifp);
	+ IFNET_WUNLOCK();
	+
	+ if_busy_wait(ifp);
	CURVNET_SET_QUIET(ifp->if_vnet);
	if_detach_internal(ifp, 0, NULL);
	CURVNET_RESTORE();
	@@ -1082,6 +1154,16 @@
	struct ifnet *iter;
	int found = 0;

	+ KASSERT((ifp->if_flags & IFF_DETACHING) != 0,
	+ ("%s: detach flag not set", __func__));
	+ if (!vmove) {
	+ KASSERT(ifp->if_busy_count == 0,
	+ ("%s: busy threads still present", __func__));
	+ KASSERT((ifp->if_flags & IFF_VMOVING) == 0,
	+ ("%s: detach while ifnet changing vnets", __func__));
	+ KASSERT((ifp->if_flags & IFF_DYING) == 0,
	+ ("%s: out of order detach/free", __func__));
	+ }
	IFNET_WLOCK();
	CK_STAILQ_FOREACH(iter, &V_ifnet, if_link)
	if (iter == ifp) {
	@@ -1250,15 +1332,8 @@
	}

	#ifdef VIMAGE
	-/*
	- * if_vmove() performs a limited version of if_detach() in current
	- * vnet and if_attach()es the ifnet to the vnet specified as 2nd arg.
	- * An attempt is made to shrink if_index in current vnet, find an
	- * unused if_index in target vnet and calls if_grow() if necessary,
	- * and finally find an unused if_xname for the target vnet.
	- */
	static int
	-if_vmove(struct ifnet ifp, struct vnet new_vnet)
	+if_vmove_busied(struct ifnet ifp, struct vnet new_vnet)
	{
	struct if_clone *ifc;
	#ifdef DEV_BPF
	@@ -1268,7 +1343,7 @@
	int rc;

	#ifdef DEV_BPF
	- /*
	+ /*
	* if_detach_internal() will call the eventhandler to notify
	* interface departure. That will detach if_bpf. We need to
	* safe the dlt and hdrlen so we can re-attach it later.
	@@ -1283,7 +1358,19 @@
	*/
	rc = if_detach_internal(ifp, 1, &ifc);
	if (rc != 0)
	- return (rc);
	+ goto out;
	+
	+ /*
	+ * We could defer clearing IFF_DETACHING until the end, but
	+ * IFF_VMOVING is sufficient for keeping the interface 'busy' until
	+ * death or ioctls are invoked, and this keeps if_flags looking somewhat
	+ * correct for what's happening right now- we've exited the detach phase
	+ * of if_vmove, and we're now attaching to the new vnet.
	+ */
	+ IF_BUSY_LOCK(ifp);
	+ if ((ifp->if_flags & IFF_VMOVING) != 0)
	+ ifp->if_flags &= ~IFF_DETACHING;
	+ IF_BUSY_UNLOCK(ifp);

	/*
	* Unlink the ifnet from ifindex_table[] in current vnet, and shrink
	@@ -1327,7 +1414,53 @@
	#endif

	CURVNET_RESTORE();
	- return (0);
	+out:
	+ /*
	+ * Either we failed or the interface is no longer visible in the current
	+ * vnet, so we can go ahead and drop IFF_DETACHED and IFF_VMOVING. If
	+ * IFF_VMOVING is no longer set, then if_detach() came along and
	+ * solidifed the detaching. We may have already cleared IFF_DETACHING
	+ * up above, but we're blocked from doing further vnet moves and
	+ * if_detach would have cleared IFF_VMOVING, so we can go ahead and
	+ * unconditionally clear it -- we'll need to clear it anyways if we're
	+ * in the error path.
	+ */
	+ IF_BUSY_LOCK(ifp);
	+ if ((ifp->if_flags & IFF_VMOVING) != 0)
	+ ifp->if_flags &= ~(IFF_DETACHING \| IFF_VMOVING);
	+ IF_BUSY_UNLOCK(ifp);
	+ return (rc);
	+}
	+
	+/*
	+ * if_vmove() performs a limited version of if_detach() in current
	+ * vnet and if_attach()es the ifnet to the vnet specified as 2nd arg.
	+ * An attempt is made to shrink if_index in current vnet, find an
	+ * unused if_index in target vnet and calls if_grow() if necessary,
	+ * and finally find an unused if_xname for the target vnet.
	+ *
	+ * The caller may indicate that it's already busied thet interface prior
	+ * to entry. If it has done so, assume it's ok to proceed with the move.
	+ * The caller will handle unbusy.
	+ */
	+static int
	+if_vmove(struct ifnet ifp, struct vnet new_vnet)
	+{
	+ int error;
	+
	+ /*
	+ * Busy the ifnet, taking into account whether this is a vnet shutdown
	+ * or not. We don't let detach block us if we're in the middle of
	+ * shutdown so that we don't end up with a vnet that still has
	+ * interfaces in it; if_detach will specifically handle the case that
	+ * the ifnet in question will be getting re-homed as it's shutting down.
	+ */
	+ if (!if_busy(ifp, IFF_DETACHING \| IFF_VMOVING))
	+ return (EBUSY);
	+
	+ error = if_vmove_busied(ifp, new_vnet);
	+ if_unbusy(ifp);
	+ return (error);
	}

	/*
	@@ -2414,6 +2547,43 @@
	return (ifp);
	}

	+#define IFF_BUSY_FLAGS (IFF_DETACHING \| IFF_DYING \| IFF_VMOVING)
	+
	+/*
	+ * Busy the interface, if it's not already detaching/dying. The caller may
	+ * request, via setflags, flags to set on the ifp while we're still holding the
	+ * busy lock if we've succeeded. The caller is responsible for clearing any
	+ * temporary flags that were set.
	+ */
	+static bool
	+if_busy(struct ifnet *ifp, int setflags)
	+{
	+
	+ IF_BUSY_LOCK(ifp);
	+ if ((ifp->if_flags & IFF_BUSY_FLAGS) != 0) {
	+ IF_BUSY_UNLOCK(ifp);
	+ return (false);
	+ }
	+ refcount_acquire(&ifp->if_busy_count);
	+ ifp->if_flags \|= setflags;
	+ IF_BUSY_UNLOCK(ifp);
	+ return (true);
	+}
	+
	+static void
	+if_unbusy(struct ifnet *ifp)
	+{
	+
	+ refcount_release(&ifp->if_busy_count);
	+}
	+
	+static void
	+if_busy_wait(struct ifnet *ifp)
	+{
	+
	+ refcount_wait(&ifp->if_busy_count, "ifbusy", 0);
	+}
	+
	static void *
	ifr_buffer_get_buffer(void *data)
	{
	@@ -2486,8 +2656,8 @@
	/*
	* Hardware specific interface ioctls.
	*/
	-int
	-ifhwioctl(u_long cmd, struct ifnet ifp, caddr_t data, struct thread td)
	+static int
	+ifhwioctl_internal(u_long cmd, struct ifnet ifp, caddr_t data, struct thread td)
	{
	struct ifreq *ifr;
	int error = 0, do_ifup = 0;
	@@ -2499,6 +2669,14 @@
	struct ifaddr *ifa;
	struct sockaddr_dl *sdl;

	+ /*
	+ * We can't assert that we're not detaching because the procedure is to
	+ * mark us as detaching then wait for the different "management" paths
	+ * to exit before proceeding with the detach. We should have properly
	+ * increased the refcount, at least.
	+ */
	+ KASSERT(ifp->if_busy_count > 0,
	+ ("%s: mgmt refcount not increased", __func__));
	ifr = (struct ifreq *)data;
	switch (cmd) {
	case SIOCGIFINDEX:
	@@ -2902,6 +3080,23 @@
	return (error);
	}

	+/*
	+ * Hardware specific interface ioctls.
	+ */
	+int
	+ifhwioctl(u_long cmd, struct ifnet ifp, caddr_t data, struct thread td)
	+{
	+ int error;
	+
	+ if (!if_busy(ifp, 0))
	+ return (ENXIO);
	+
	+ error = ifhwioctl_internal(cmd, ifp, data, td);
	+
	+ if_unbusy(ifp);
	+ return (error);
	+}
	+
	#ifdef COMPAT_FREEBSD32
	struct ifconf32 {
	int32_t ifc_len;
	@@ -2972,7 +3167,7 @@
	switch (cmd) {
	case SIOCGIFCONF:
	error = ifconf(cmd, data);
	- goto out_noref;
	+ goto out_notbusy;

	#ifdef COMPAT_FREEBSD32
	case SIOCGIFCONF32:
	@@ -2987,7 +3182,7 @@
	error = ifconf(SIOCGIFCONF, (void *)&ifc);
	if (error == 0)
	ifc32->ifc_len = ifc.ifc_len;
	- goto out_noref;
	+ goto out_notbusy;
	}
	#endif
	}
	@@ -3012,7 +3207,7 @@
	if (error == 0)
	error = if_vmove_reclaim(td, ifr->ifr_name,
	ifr->ifr_jid);
	- goto out_noref;
	+ goto out_notbusy;
	#endif
	case SIOCIFCREATE:
	case SIOCIFCREATE2:
	@@ -3021,20 +3216,20 @@
	error = if_clone_create(ifr->ifr_name,
	sizeof(ifr->ifr_name), cmd == SIOCIFCREATE2 ?
	ifr_data_get_ptr(ifr) : NULL);
	- goto out_noref;
	+ goto out_notbusy;
	case SIOCIFDESTROY:
	error = priv_check(td, PRIV_NET_IFDESTROY);
	if (error == 0)
	error = if_clone_destroy(ifr->ifr_name);
	- goto out_noref;
	+ goto out_notbusy;

	case SIOCIFGCLONERS:
	error = if_clone_list((struct if_clonereq *)data);
	- goto out_noref;
	+ goto out_notbusy;

	case CASE_IOC_IFGROUPREQ(SIOCGIFGMEMB):
	error = if_getgroupmembers((struct ifgroupreq *)data);
	- goto out_noref;
	+ goto out_notbusy;

	#if defined(INET) \|\| defined(INET6)
	case SIOCSVH:
	@@ -3043,24 +3238,34 @@
	error = EPROTONOSUPPORT;
	else
	error = (*carp_ioctl_p)(ifr, cmd, td);
	- goto out_noref;
	+ goto out_notbusy;
	#endif
	}

	- ifp = ifunit_ref(ifr->ifr_name);
	+ /*
	+ * Don't increment the refcount; we'll do administrative refcounting as
	+ * we want to ensure that we're no longer busy before
	+ * if_detach/if_free may proceed.
	+ */
	+ ifp = ifunit(ifr->ifr_name);
	if (ifp == NULL) {
	error = ENXIO;
	- goto out_noref;
	+ goto out_notbusy;
	+ }
	+
	+ if (!if_busy(ifp, 0)) {
	+ error = ENXIO;
	+ goto out_notbusy;
	}

	- error = ifhwioctl(cmd, ifp, data, td);
	+ error = ifhwioctl_internal(cmd, ifp, data, td);
	if (error != ENOIOCTL)
	- goto out_ref;
	+ goto out_busy;

	oif_flags = ifp->if_flags;
	if (so->so_proto == NULL) {
	error = EOPNOTSUPP;
	- goto out_ref;
	+ goto out_busy;
	}

	/*
	@@ -3086,9 +3291,9 @@
	#endif
	}

	-out_ref:
	- if_rele(ifp);
	-out_noref:
	+out_busy:
	+ if_unbusy(ifp);
	+out_notbusy:
	#ifdef COMPAT_FREEBSD32
	if (ifmrp != NULL) {
	KASSERT((cmd == SIOCGIFMEDIA \|\| cmd == SIOCGIFXMEDIA),
	Index: sys/net/if_tuntap.c
	===================================================================
	--- sys/net/if_tuntap.c
	+++ sys/net/if_tuntap.c
	@@ -190,9 +190,6 @@
	static TAILQ_HEAD(,tuntap_softc) tunhead = TAILQ_HEAD_INITIALIZER(tunhead);
	SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, "");

	-static struct sx tun_ioctl_sx;
	-SX_SYSINIT(tun_ioctl_sx, &tun_ioctl_sx, "tun_ioctl");
	-
	SYSCTL_DECL(_net_link);
	/* tun */
	static SYSCTL_NODE(_net_link, OID_AUTO, tun, CTLFLAG_RW, 0,
	@@ -641,9 +638,6 @@
	bpfdetach(TUN2IFP(tp));
	if_detach(TUN2IFP(tp));
	}
	- sx_xlock(&tun_ioctl_sx);
	- TUN2IFP(tp)->if_softc = NULL;
	- sx_xunlock(&tun_ioctl_sx);
	free_unr(tp->tun_drv->unrhdr, TUN2IFP(tp)->if_dunit);
	if_free(TUN2IFP(tp));
	mtx_destroy(&tp->tun_mtx);
	@@ -1011,14 +1005,8 @@
	* from dying until we've created the alias (that will then be
	* subsequently destroyed).
	*/
	- sx_xlock(&tun_ioctl_sx);
	tp = ifp->if_softc;
	- if (tp == NULL) {
	- sx_xunlock(&tun_ioctl_sx);
	- return;
	- }
	error = tun_busy(tp);
	- sx_xunlock(&tun_ioctl_sx);
	if (error != 0)
	return;
	if (tp->tun_alias != NULL) {
	@@ -1324,12 +1312,7 @@
	bool l2tun;

	ifmr = NULL;
	- sx_xlock(&tun_ioctl_sx);
	tp = ifp->if_softc;
	- if (tp == NULL) {
	- error = ENXIO;
	- goto bad;
	- }
	l2tun = (tp->tun_flags & TUN_L2) != 0;
	switch(cmd) {
	case SIOCGIFSTATUS:
	@@ -1391,8 +1374,6 @@
	error = EINVAL;
	}
	}
	-bad:
	- sx_xunlock(&tun_ioctl_sx);
	return (error);
	}

	Index: sys/net/if_var.h
	===================================================================
	--- sys/net/if_var.h
	+++ sys/net/if_var.h
	@@ -423,6 +423,13 @@
	struct debugnet_methods *if_debugnet_methods;
	struct epoch_context if_epoch_ctx;

	+ /*
	+ * Bits for serializing management operations (ioctl/destroy/vmove)
	+ * and ensuring order.
	+ */
	+ struct mtx if_busy_lock;
	+ u_int if_busy_count;
	+
	/*
	* Spare fields to be added before branching a stable branch, so
	* that structure can be enhanced without changing the kernel
	@@ -450,6 +457,12 @@
	#define NET_EPOCH_WAIT() epoch_wait_preempt(net_epoch_preempt)
	#define NET_EPOCH_ASSERT() MPASS(in_epoch(net_epoch_preempt))

	+#define IF_BUSY_LOCK_INIT(if) mtx_init(&(if)->if_busy_lock, "if_busy_lock", NULL, MTX_DEF)
	+#define IF_BUSY_LOCK_DESTROY(if) mtx_destroy(&(if)->if_busy_lock)
	+#define IF_BUSY_LOCK(if) mtx_lock(&(if)->if_busy_lock)
	+#define IF_BUSY_UNLOCK(if) mtx_unlock(&(if)->if_busy_lock)
	+#define IF_BUSY_LOCK_ASSERT(if) mtx_assert(&(if)->if_busy_lock, MA_OWNED)
	+
	#ifdef _KERNEL
	/* interface link layer address change event */
	typedef void (iflladdr_event_handler_t)(void , struct ifnet *);

File Metadata

Mime Type: text/plain
Expires: Thu, May 21, 8:57 AM (20 h, 3 m)
Storage Engine: blob
Storage Format: Raw Data
Storage Handle: 33382938
Default Alt Text: D22691.id65557.diff (16 KB)

D22691.id65557.diffNo OneTemporaryActions

D22691.id65557.diffView Options

File Metadata

Event Timeline

D22691.id65557.diff
No OneTemporary
Actions

D22691.id65557.diff
View Options