Change KPI of how device drivers that provide wireless connectivity interact

with the net80211 stack.

Historical background: originally wireless devices created an interface,
just like Ethernet devices do. Name of an interface matched the name of
the driver that created. Later, wlan(4) layer was introduced, and the
wlanX interfaces become the actual interface, leaving original ones as
"a parent interface" of wlanX. Kernelwise, the KPI between net80211 layer
and a driver became a mix of methods that pass a pointer to struct ifnet
as identifier and methods that pass pointer to struct ieee80211com. From
user point of view, the parent interface just hangs on in the ifconfig
list, and user can't do anything useful with it.

Now, the struct ifnet goes away. The struct ieee80211com is the only
KPI between a device driver and net80211. Details:

- The struct ieee80211com is embedded into drivers softc.
- Packets are sent via new ic_transmit method, which is very much like
  the previous if_transmit.
- Bringing parent up/down is done via new ic_parent method, which notifies
  driver about any changes: number of wlan(4) interfaces, number of them
  in promisc or allmulti state.
- Device specific ioctls (if any) are received on new ic_ioctl method.
- Packets/errors accounting are done by the stack. In certain cases, when
  driver experiences errors and can not attribute them to any specific
  interface, driver updates ic_oerrors or ic_ierrors counters.

Details on interface configuration with new world order:
- A sequence of commands needed to bring up wireless DOESN"T change.
- /etc/rc.conf parameters DON'T change.
- List of devices that can be used to create wlan(4) interfaces is
  now provided by net.wlan.devices sysctl.

Most drivers in this change were converted by me, except of wpi(4),
that was done by Andriy Voskoboinyk. Big thanks to Kevin Lo for testing
changes to at least 8 drivers. Thanks to Olivier Cochard, gjb@, mmoll@,
op@ and lev@, who also participated in testing. Details here:

https://wiki.freebsd.org/projects/ifnet/net80211

Still, drivers: ndis, wtap, mwl, ipw, bwn, wi, upgt, uath were not
tested. Changes to mwl, ipw, bwn, wi, upgt are trivial and chances
of problems are low. The wtap wasn't compilable even before this change.
But the ndis driver is complex, and it is likely to be broken with this
commit. Help with testing and debugging it is appreciated.

Differential Revision:	D2655, D2740
Sponsored by:	Nginx, Inc.
Sponsored by:	Netflix

1 files changed, 109 insertions, 173 deletions

diff --git a/sys/net80211/ieee80211.c b/sys/net80211/ieee80211.c
index 3902227e8c43..39e03eaff93f 100644
--- a/sys/net80211/ieee80211.c
+++ b/sys/net80211/ieee80211.c
@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/kernel.h>
 #include <sys/socket.h>
+#include <sys/sbuf.h>
 
 #include <machine/stdarg.h>
 
@@ -91,8 +92,6 @@ static	void ieee80211_syncflag_ext_locked(struct ieee80211com *ic, int flag);
 static	int ieee80211_media_setup(struct ieee80211com *ic,
 		struct ifmedia *media, int caps, int addsta,
 		ifm_change_cb_t media_change, ifm_stat_cb_t media_stat);
-static	void ieee80211com_media_status(struct ifnet *, struct ifmediareq *);
-static	int ieee80211com_media_change(struct ifnet *);
 static	int media_status(enum ieee80211_opmode,
 		const struct ieee80211_channel *);
 static uint64_t ieee80211_get_counter(struct ifnet *, ift_counter);
@@ -121,7 +120,7 @@ static const struct ieee80211_rateset ieee80211_rateset_11g =
  * all available channels as active, and pick
  * a default channel if not already specified.
  */
-static void
+void
 ieee80211_chan_init(struct ieee80211com *ic)
 {
 #define	DEFAULTRATES(m, def) do { \
@@ -238,29 +237,6 @@ null_update_promisc(struct ieee80211com *ic)
 	ic_printf(ic, "need promiscuous mode update callback\n");
 }
 
-static int
-null_transmit(struct ifnet *ifp, struct mbuf *m)
-{
-	m_freem(m);
-	if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
-	return EACCES;		/* XXX EIO/EPERM? */
-}
-
-static int
-null_output(struct ifnet *ifp, struct mbuf *m,
-	const struct sockaddr *dst, struct route *ro)
-{
-	if_printf(ifp, "discard raw packet\n");
-	return null_transmit(ifp, m);
-}
-
-static void
-null_input(struct ifnet *ifp, struct mbuf *m)
-{
-	if_printf(ifp, "if_input should not be called\n");
-	m_freem(m);
-}
-
 static void
 null_update_chw(struct ieee80211com *ic)
 {
@@ -281,19 +257,43 @@ ic_printf(struct ieee80211com *ic, const char * fmt, ...)
 	return (retval);
 }
 
+static LIST_HEAD(, ieee80211com) ic_head = LIST_HEAD_INITIALIZER(ic_head);
+static struct mtx ic_list_mtx;
+MTX_SYSINIT(ic_list, &ic_list_mtx, "ieee80211com list", MTX_DEF);
+
+static int
+sysctl_ieee80211coms(SYSCTL_HANDLER_ARGS)
+{
+	struct ieee80211com *ic;
+	struct sbuf *sb;
+	char *sp;
+	int error;
+
+	sb = sbuf_new_auto();
+	sp = "";
+	mtx_lock(&ic_list_mtx);
+	LIST_FOREACH(ic, &ic_head, ic_next) {
+		sbuf_printf(sb, "%s%s", sp, ic->ic_name);
+		sp = " ";
+	}
+	mtx_unlock(&ic_list_mtx);
+	sbuf_finish(sb);
+	error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
+	sbuf_delete(sb);
+	return (error);
+}
+
+SYSCTL_PROC(_net_wlan, OID_AUTO, devices,
+    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
+    sysctl_ieee80211coms, "A", "names of available 802.11 devices");
+
 /*
  * Attach/setup the common net80211 state.  Called by
  * the driver on attach to prior to creating any vap's.
  */
 void
-ieee80211_ifattach(struct ieee80211com *ic,
-	const uint8_t macaddr[IEEE80211_ADDR_LEN])
+ieee80211_ifattach(struct ieee80211com *ic)
 {
-	struct ifnet *ifp = ic->ic_ifp;
-	struct sockaddr_dl *sdl;
-	struct ifaddr *ifa;
-
-	KASSERT(ifp->if_type == IFT_IEEE80211, ("if_type %d", ifp->if_type));
 
 	IEEE80211_LOCK_INIT(ic, ic->ic_name);
 	IEEE80211_TX_LOCK_INIT(ic, ic->ic_name);
@@ -311,7 +311,7 @@ ieee80211_ifattach(struct ieee80211com *ic,
 	 * available channels as active, and pick a default
 	 * channel if not already specified.
 	 */
-	ieee80211_media_init(ic);
+	ieee80211_chan_init(ic);
 
 	ic->ic_update_mcast = null_update_mcast;
 	ic->ic_update_promisc = null_update_promisc;
@@ -336,28 +336,9 @@ ieee80211_ifattach(struct ieee80211com *ic,
 
 	ieee80211_sysctl_attach(ic);
 
-	ifp->if_addrlen = IEEE80211_ADDR_LEN;
-	ifp->if_hdrlen = 0;
-
-	CURVNET_SET(vnet0);
-
-	if_attach(ifp);
-
-	ifp->if_mtu = IEEE80211_MTU_MAX;
-	ifp->if_broadcastaddr = ieee80211broadcastaddr;
-	ifp->if_output = null_output;
-	ifp->if_input = null_input;	/* just in case */
-	ifp->if_resolvemulti = NULL;	/* NB: callers check */
-
-	ifa = ifaddr_byindex(ifp->if_index);
-	KASSERT(ifa != NULL, ("%s: no lladdr!\n", __func__));
-	sdl = (struct sockaddr_dl *)ifa->ifa_addr;
-	sdl->sdl_type = IFT_ETHER;		/* XXX IFT_IEEE80211? */
-	sdl->sdl_alen = IEEE80211_ADDR_LEN;
-	IEEE80211_ADDR_COPY(LLADDR(sdl), macaddr);
-	ifa_free(ifa);
-
-	CURVNET_RESTORE();
+	mtx_lock(&ic_list_mtx);
+	LIST_INSERT_HEAD(&ic_head, ic, ic_next);
+	mtx_unlock(&ic_list_mtx);
 }
 
 /*
@@ -369,16 +350,11 @@ ieee80211_ifattach(struct ieee80211com *ic,
 void
 ieee80211_ifdetach(struct ieee80211com *ic)
 {
-	struct ifnet *ifp = ic->ic_ifp;
 	struct ieee80211vap *vap;
 
-	/*
-	 * This detaches the main interface, but not the vaps.
-	 * Each VAP may be in a separate VIMAGE.
-	 */
-	CURVNET_SET(ifp->if_vnet);
-	if_detach(ifp);
-	CURVNET_RESTORE();
+	mtx_lock(&ic_list_mtx);
+	LIST_REMOVE(ic, ic_next);
+	mtx_unlock(&ic_list_mtx);
 
 	/*
 	 * The VAP is responsible for setting and clearing
@@ -402,8 +378,6 @@ ieee80211_ifdetach(struct ieee80211com *ic)
 	ieee80211_power_detach(ic);
 	ieee80211_node_detach(ic);
 
-	/* XXX VNET needed? */
-	ifmedia_removeall(&ic->ic_media);
 	counter_u64_free(ic->ic_ierrors);
 	counter_u64_free(ic->ic_oerrors);
 
@@ -412,6 +386,20 @@ ieee80211_ifdetach(struct ieee80211com *ic)
 	IEEE80211_LOCK_DESTROY(ic);
 }
 
+struct ieee80211com *
+ieee80211_find_com(const char *name)
+{
+	struct ieee80211com *ic;
+
+	mtx_lock(&ic_list_mtx);
+	LIST_FOREACH(ic, &ic_head, ic_next)
+		if (strcmp(ic->ic_name, name) == 0)
+			break;
+	mtx_unlock(&ic_list_mtx);
+
+	return (ic);
+}
+
 /*
  * Default reset method for use with the ioctl support.  This
  * method is invoked after any state change in the 802.11
@@ -460,8 +448,7 @@ ieee80211_get_counter(struct ifnet *ifp, ift_counter cnt)
 int
 ieee80211_vap_setup(struct ieee80211com *ic, struct ieee80211vap *vap,
     const char name[IFNAMSIZ], int unit, enum ieee80211_opmode opmode,
-    int flags, const uint8_t bssid[IEEE80211_ADDR_LEN],
-    const uint8_t macaddr[IEEE80211_ADDR_LEN])
+    int flags, const uint8_t bssid[IEEE80211_ADDR_LEN])
 {
 	struct ifnet *ifp;
 
@@ -490,6 +477,7 @@ ieee80211_vap_setup(struct ieee80211com *ic, struct ieee80211vap *vap,
 	vap->iv_htextcaps = ic->ic_htextcaps;
 	vap->iv_opmode = opmode;
 	vap->iv_caps |= ieee80211_opcap[opmode];
+	vap->iv_myaddr = ic->ic_macaddr;
 	switch (opmode) {
 	case IEEE80211_M_WDS:
 		/*
@@ -556,8 +544,6 @@ ieee80211_vap_setup(struct ieee80211com *ic, struct ieee80211vap *vap,
 	 */
 	vap->iv_reset = default_reset;
 
-	IEEE80211_ADDR_COPY(vap->iv_myaddr, macaddr);
-
 	ieee80211_sysctl_vattach(vap);
 	ieee80211_crypto_vattach(vap);
 	ieee80211_node_vattach(vap);
@@ -581,8 +567,8 @@ ieee80211_vap_setup(struct ieee80211com *ic, struct ieee80211vap *vap,
  * from this call the vap is ready for use.
  */
 int
-ieee80211_vap_attach(struct ieee80211vap *vap,
-	ifm_change_cb_t media_change, ifm_stat_cb_t media_stat)
+ieee80211_vap_attach(struct ieee80211vap *vap, ifm_change_cb_t media_change,
+    ifm_stat_cb_t media_stat, const uint8_t macaddr[IEEE80211_ADDR_LEN])
 {
 	struct ifnet *ifp = vap->iv_ifp;
 	struct ieee80211com *ic = vap->iv_ic;
@@ -610,7 +596,8 @@ ieee80211_vap_attach(struct ieee80211vap *vap,
 	if (maxrate)
 		ifp->if_baudrate = IF_Mbps(maxrate);
 
-	ether_ifattach(ifp, vap->iv_myaddr);
+	ether_ifattach(ifp, macaddr);
+	vap->iv_myaddr = IF_LLADDR(ifp);
 	/* hook output method setup by ether_ifattach */
 	vap->iv_output = ifp->if_output;
 	ifp->if_output = ieee80211_output;
@@ -626,8 +613,6 @@ ieee80211_vap_attach(struct ieee80211vap *vap,
 	ieee80211_syncflag_locked(ic, IEEE80211_F_BURST);
 	ieee80211_syncflag_ht_locked(ic, IEEE80211_FHT_HT);
 	ieee80211_syncflag_ht_locked(ic, IEEE80211_FHT_USEHT40);
-	ieee80211_syncifflag_locked(ic, IFF_PROMISC);
-	ieee80211_syncifflag_locked(ic, IFF_ALLMULTI);
 	IEEE80211_UNLOCK(ic);
 
 	return 1;
@@ -677,8 +662,10 @@ ieee80211_vap_detach(struct ieee80211vap *vap)
 	ieee80211_syncflag_ht_locked(ic, IEEE80211_FHT_USEHT40);
 	/* NB: this handles the bpfdetach done below */
 	ieee80211_syncflag_ext_locked(ic, IEEE80211_FEXT_BPF);
-	ieee80211_syncifflag_locked(ic, IFF_PROMISC);
-	ieee80211_syncifflag_locked(ic, IFF_ALLMULTI);
+	if (vap->iv_ifflags & IFF_PROMISC)
+		ieee80211_promisc(vap, false);
+	if (vap->iv_ifflags & IFF_ALLMULTI)
+		ieee80211_allmulti(vap, false);
 	IEEE80211_UNLOCK(ic);
 
 	ifmedia_removeall(&vap->iv_media);
@@ -703,49 +690,57 @@ ieee80211_vap_detach(struct ieee80211vap *vap)
 }
 
 /*
- * Synchronize flag bit state in the parent ifnet structure
- * according to the state of all vap ifnet's.  This is used,
- * for example, to handle IFF_PROMISC and IFF_ALLMULTI.
+ * Count number of vaps in promisc, and issue promisc on
+ * parent respectively.
  */
 void
-ieee80211_syncifflag_locked(struct ieee80211com *ic, int flag)
+ieee80211_promisc(struct ieee80211vap *vap, bool on)
 {
-	struct ifnet *ifp = ic->ic_ifp;
-	struct ieee80211vap *vap;
-	int bit, oflags;
+	struct ieee80211com *ic = vap->iv_ic;
 
-	IEEE80211_LOCK_ASSERT(ic);
+	/*
+	 * XXX the bridge sets PROMISC but we don't want to
+	 * enable it on the device, discard here so all the
+	 * drivers don't need to special-case it
+	 */
+	if (!(vap->iv_opmode == IEEE80211_M_MONITOR ||
+	      (vap->iv_opmode == IEEE80211_M_AHDEMO &&
+	       (vap->iv_caps & IEEE80211_C_TDMA) == 0)))
+			return;
 
-	bit = 0;
-	TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next)
-		if (vap->iv_ifp->if_flags & flag) {
-			/*
-			 * XXX the bridge sets PROMISC but we don't want to
-			 * enable it on the device, discard here so all the
-			 * drivers don't need to special-case it
-			 */
-			if (flag == IFF_PROMISC &&
-			    !(vap->iv_opmode == IEEE80211_M_MONITOR ||
-			      (vap->iv_opmode == IEEE80211_M_AHDEMO &&
-			       (vap->iv_caps & IEEE80211_C_TDMA) == 0)))
-				continue;
-			bit = 1;
-			break;
-		}
-	oflags = ifp->if_flags;
-	if (bit)
-		ifp->if_flags |= flag;
-	else
-		ifp->if_flags &= ~flag;
-	if ((ifp->if_flags ^ oflags) & flag) {
-		/* XXX should we return 1/0 and let caller do this? */
-		if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
-			if (flag == IFF_PROMISC)
-				ieee80211_runtask(ic, &ic->ic_promisc_task);
-			else if (flag == IFF_ALLMULTI)
-				ieee80211_runtask(ic, &ic->ic_mcast_task);
-		}
+	IEEE80211_LOCK(ic);
+	if (on) {
+		if (++ic->ic_promisc == 1)
+			ieee80211_runtask(ic, &ic->ic_promisc_task);
+	} else {
+		KASSERT(ic->ic_promisc > 0, ("%s: ic %p not promisc",
+		    __func__, ic));
+		if (--ic->ic_promisc == 0)
+			ieee80211_runtask(ic, &ic->ic_promisc_task);
 	}
+	IEEE80211_UNLOCK(ic);
+}
+
+/*
+ * Count number of vaps in allmulti, and issue allmulti on
+ * parent respectively.
+ */
+void
+ieee80211_allmulti(struct ieee80211vap *vap, bool on)
+{
+	struct ieee80211com *ic = vap->iv_ic;
+
+	IEEE80211_LOCK(ic);
+	if (on) {
+		if (++ic->ic_allmulti == 1)
+			ieee80211_runtask(ic, &ic->ic_mcast_task);
+	} else {
+		KASSERT(ic->ic_allmulti > 0, ("%s: ic %p not allmulti",
+		    __func__, ic));
+		if (--ic->ic_allmulti == 0)
+			ieee80211_runtask(ic, &ic->ic_mcast_task);
+	}
+	IEEE80211_UNLOCK(ic);
 }
 
 /*
@@ -1234,39 +1229,6 @@ ieee80211_media_setup(struct ieee80211com *ic,
 	return maxrate;
 }
 
-void
-ieee80211_media_init(struct ieee80211com *ic)
-{
-	struct ifnet *ifp = ic->ic_ifp;
-	int maxrate;
-
-	/* NB: this works because the structure is initialized to zero */
-	if (!LIST_EMPTY(&ic->ic_media.ifm_list)) {
-		/*
-		 * We are re-initializing the channel list; clear
-		 * the existing media state as the media routines
-		 * don't suppress duplicates.
-		 */
-		ifmedia_removeall(&ic->ic_media);
-	}
-	ieee80211_chan_init(ic);
-
-	/*
-	 * Recalculate media settings in case new channel list changes
-	 * the set of available modes.
-	 */
-	maxrate = ieee80211_media_setup(ic, &ic->ic_media, ic->ic_caps, 1,
-		ieee80211com_media_change, ieee80211com_media_status);
-	/* NB: strip explicit mode; we're actually in autoselect */
-	ifmedia_set(&ic->ic_media,
-	    media_status(ic->ic_opmode, ic->ic_curchan) &~
-		(IFM_MMASK | IFM_IEEE80211_TURBO));
-	if (maxrate)
-		ifp->if_baudrate = IF_Mbps(maxrate);
-
-	/* XXX need to propagate new media settings to vap's */
-}
-
 /* XXX inline or eliminate? */
 const struct ieee80211_rateset *
 ieee80211_get_suprates(struct ieee80211com *ic, const struct ieee80211_channel *c)
@@ -1395,15 +1357,6 @@ media2mode(const struct ifmedia_entry *ime, uint32_t flags, uint16_t *mode)
 }
 
 /*
- * Handle a media change request on the underlying interface.
- */
-int
-ieee80211com_media_change(struct ifnet *ifp)
-{
-	return EINVAL;
-}
-
-/*
  * Handle a media change request on the vap interface.
  */
 int
@@ -1480,23 +1433,6 @@ media_status(enum ieee80211_opmode opmode, const struct ieee80211_channel *chan)
 	return status;
 }
 
-static void
-ieee80211com_media_status(struct ifnet *ifp, struct ifmediareq *imr)
-{
-	struct ieee80211com *ic = ifp->if_l2com;
-	struct ieee80211vap *vap;
-
-	imr->ifm_status = IFM_AVALID;
-	TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next)
-		if (vap->iv_ifp->if_flags & IFF_UP) {
-			imr->ifm_status |= IFM_ACTIVE;
-			break;
-		}
-	imr->ifm_active = media_status(ic->ic_opmode, ic->ic_curchan);
-	if (imr->ifm_status & IFM_ACTIVE)
-		imr->ifm_current = imr->ifm_active;
-}
-
 void
 ieee80211_media_status(struct ifnet *ifp, struct ifmediareq *imr)
 {