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, 14 insertions, 76 deletions

diff --git a/sys/net80211/ieee80211_freebsd.c b/sys/net80211/ieee80211_freebsd.c
index 3af75df..9a8e941 100644
--- a/sys/net80211/ieee80211_freebsd.c
+++ b/sys/net80211/ieee80211_freebsd.c
@@ -69,58 +69,27 @@ static MALLOC_DEFINE(M_80211_COM, "80211com", "802.11 com state");
 static const char wlanname[] = "wlan";
 static struct if_clone *wlan_cloner;
 
-/*
- * Allocate/free com structure in conjunction with ifnet;
- * these routines are registered with if_register_com_alloc
- * below and are called automatically by the ifnet code
- * when the ifnet of the parent device is created.
- */
-static void *
-wlan_alloc(u_char type, struct ifnet *ifp)
-{
-	struct ieee80211com *ic;
-
-	ic = IEEE80211_MALLOC(sizeof(struct ieee80211com), M_80211_COM,
-	    IEEE80211_M_WAITOK | IEEE80211_M_ZERO);
-	ic->ic_ifp = ifp;
-
-	return (ic);
-}
-
-static void
-wlan_free(void *ic, u_char type)
-{
-	IEEE80211_FREE(ic, M_80211_COM);
-}
-
 static int
 wlan_clone_create(struct if_clone *ifc, int unit, caddr_t params)
 {
 	struct ieee80211_clone_params cp;
 	struct ieee80211vap *vap;
 	struct ieee80211com *ic;
-	struct ifnet *ifp;
 	int error;
 
 	error = copyin(params, &cp, sizeof(cp));
 	if (error)
 		return error;
-	ifp = ifunit(cp.icp_parent);
-	if (ifp == NULL)
+	ic = ieee80211_find_com(cp.icp_parent);
+	if (ic == NULL)
 		return ENXIO;
-	/* XXX move printfs to DIAGNOSTIC before release */
-	if (ifp->if_type != IFT_IEEE80211) {
-		if_printf(ifp, "%s: reject, not an 802.11 device\n", __func__);
-		return ENXIO;
-	}
 	if (cp.icp_opmode >= IEEE80211_OPMODE_MAX) {
-		if_printf(ifp, "%s: invalid opmode %d\n",
-		    __func__, cp.icp_opmode);
+		ic_printf(ic, "%s: invalid opmode %d\n", __func__,
+		    cp.icp_opmode);
 		return EINVAL;
 	}
-	ic = ifp->if_l2com;
 	if ((ic->ic_caps & ieee80211_opcap[cp.icp_opmode]) == 0) {
-		if_printf(ifp, "%s mode not supported\n",
+		ic_printf(ic, "%s mode not supported\n",
 		    ieee80211_opmode_name[cp.icp_opmode]);
 		return EOPNOTSUPP;
 	}
@@ -131,13 +100,13 @@ wlan_clone_create(struct if_clone *ifc, int unit, caddr_t params)
 	    (1)
 #endif
 	) {
-		if_printf(ifp, "TDMA not supported\n");
+		ic_printf(ic, "TDMA not supported\n");
 		return EOPNOTSUPP;
 	}
 	vap = ic->ic_vap_create(ic, wlanname, unit,
 			cp.icp_opmode, cp.icp_flags, cp.icp_bssid,
 			cp.icp_flags & IEEE80211_CLONE_MACADDR ?
-			    cp.icp_macaddr : (const uint8_t *)IF_LLADDR(ifp));
+			    cp.icp_macaddr : ic->ic_macaddr);
 
 	return (vap == NULL ? EIO : 0);
 }
@@ -528,17 +497,19 @@ ieee80211_process_callback(struct ieee80211_node *ni,
  *   (the callers will first need modifying.)
  */
 int
-ieee80211_parent_xmitpkt(struct ieee80211com *ic,
-	struct mbuf *m)
+ieee80211_parent_xmitpkt(struct ieee80211com *ic, struct mbuf *m)
 {
-	struct ifnet *parent = ic->ic_ifp;
+	int error;
+
 	/*
 	 * Assert the IC TX lock is held - this enforces the
 	 * processing -> queuing order is maintained
 	 */
 	IEEE80211_TX_LOCK_ASSERT(ic);
-
-	return (parent->if_transmit(parent, m));
+	error = ic->ic_transmit(ic, m);
+	if (error)
+		m_freem(m);
+	return (error);
 }
 
 /*
@@ -836,7 +807,6 @@ ieee80211_load_module(const char *modname)
 }
 
 static eventhandler_tag wlan_bpfevent;
-static eventhandler_tag wlan_ifllevent;
 
 static void
 bpf_track(void *arg, struct ifnet *ifp, int dlt, int attach)
@@ -864,33 +834,6 @@ bpf_track(void *arg, struct ifnet *ifp, int dlt, int attach)
 	}
 }
 
-static void
-wlan_iflladdr(void *arg __unused, struct ifnet *ifp)
-{
-	struct ieee80211com *ic = ifp->if_l2com;
-	struct ieee80211vap *vap, *next;
-
-	if (ifp->if_type != IFT_IEEE80211 || ic == NULL)
-		return;
-
-	IEEE80211_LOCK(ic);
-	TAILQ_FOREACH_SAFE(vap, &ic->ic_vaps, iv_next, next) {
-		/*
-		 * If the MAC address has changed on the parent and it was
-		 * copied to the vap on creation then re-sync.
-		 */
-		if (vap->iv_ic == ic &&
-		    (vap->iv_flags_ext & IEEE80211_FEXT_UNIQMAC) == 0) {
-			IEEE80211_ADDR_COPY(vap->iv_myaddr, IF_LLADDR(ifp));
-			IEEE80211_UNLOCK(ic);
-			if_setlladdr(vap->iv_ifp, IF_LLADDR(ifp),
-			    IEEE80211_ADDR_LEN);
-			IEEE80211_LOCK(ic);
-		}
-	}
-	IEEE80211_UNLOCK(ic);
-}
-
 /*
  * Module glue.
  *
@@ -905,17 +848,12 @@ wlan_modevent(module_t mod, int type, void *unused)
 			printf("wlan: <802.11 Link Layer>\n");
 		wlan_bpfevent = EVENTHANDLER_REGISTER(bpf_track,
 		    bpf_track, 0, EVENTHANDLER_PRI_ANY);
-		wlan_ifllevent = EVENTHANDLER_REGISTER(iflladdr_event,
-		    wlan_iflladdr, NULL, EVENTHANDLER_PRI_ANY);
 		wlan_cloner = if_clone_simple(wlanname, wlan_clone_create,
 		    wlan_clone_destroy, 0);
-		if_register_com_alloc(IFT_IEEE80211, wlan_alloc, wlan_free);
 		return 0;
 	case MOD_UNLOAD:
-		if_deregister_com_alloc(IFT_IEEE80211);
 		if_clone_detach(wlan_cloner);
 		EVENTHANDLER_DEREGISTER(bpf_track, wlan_bpfevent);
-		EVENTHANDLER_DEREGISTER(iflladdr_event, wlan_ifllevent);
 		return 0;
 	}
 	return EINVAL;