net80211: stub SIOCS80211SCAN, make ifconfig scan instant.

The following removes the functionality of the SIOCS80211SCAN ioctl.
After long discussions with stps@, mpi@, and deraadt@ we decided that
this was the correct way of fixing ifconfig scan from blocking the
network stack.

The kernel will continue scanning in the background and filling the
nodes array, but ifconfig scan commands will now basically do just a
SIOCG80211ALLNODES and pretty print the array. So the output stays the
same but is instant.

In fact, when the interface is freshly brought up, if you type fast
enough, you can see the array being filled by running multiple ifconfig
scans in sequence.

The SIOCS80211SCAN ioctl stays for now as wi(4), pgt(4) and malo(4)
still need it around. But not for long...

Another change that this introduces is the fact that ifconfig scan no
longer plays with UP and DOWN. If the interface is down it complains and
exits. This is needed in order to maintain the nodes list.

Works on iwm(4), iwn(4), urtwn(4), run(4) and athn(4).

Tested by mpi@, landry@, florian@, thanks!
OK mpi@.

12 files changed, 26 insertions, 100 deletions

diff --git a/sys/dev/ic/athn.c b/sys/dev/ic/athn.c
index 54f1e668f7d..9e8b2924c70 100644
--- a/sys/dev/ic/athn.c
+++ b/sys/dev/ic/athn.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: athn.c,v 1.98 2017/07/03 09:21:09 kevlo Exp $	*/
+/*	$OpenBSD: athn.c,v 1.99 2018/04/26 12:50:07 pirofti Exp $	*/
 
 /*-
  * Copyright (c) 2009 Damien Bergamini <damien.bergamini@free.fr>
@@ -2917,8 +2917,6 @@ athn_stop(struct ifnet *ifp, int disable)
 	ifq_clr_oactive(&ifp->if_snd);
 
 	timeout_del(&sc->scan_to);
-	/* In case we were scanning, release the scan "lock". */
-	ic->ic_scan_lock = IEEE80211_SCAN_UNLOCKED;
 
 	ieee80211_new_state(ic, IEEE80211_S_INIT, -1);
 
diff --git a/sys/dev/ic/bwfm.c b/sys/dev/ic/bwfm.c
index 8a2f1beaddd..b7dabd17743 100644
--- a/sys/dev/ic/bwfm.c
+++ b/sys/dev/ic/bwfm.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bwfm.c,v 1.41 2018/02/11 05:33:12 patrick Exp $ */
+/* $OpenBSD: bwfm.c,v 1.42 2018/04/26 12:50:07 pirofti Exp $ */
 /*
  * Copyright (c) 2010-2016 Broadcom Corporation
  * Copyright (c) 2016,2017 Patrick Wildt <patrick@blueri.se>
@@ -463,9 +463,6 @@ bwfm_stop(struct ifnet *ifp)
 	ifp->if_flags &= ~IFF_RUNNING;
 	ifq_clr_oactive(&ifp->if_snd);
 
-	/* In case we were scanning, release the scan "lock". */
-	ic->ic_scan_lock = IEEE80211_SCAN_UNLOCKED;
-
 	ieee80211_new_state(ic, IEEE80211_S_INIT, -1);
 
 	bwfm_fwvar_cmd_set_int(sc, BWFM_C_DOWN, 1);
diff --git a/sys/dev/pci/if_ipw.c b/sys/dev/pci/if_ipw.c
index 57532466efd..9897738a8a8 100644
--- a/sys/dev/pci/if_ipw.c
+++ b/sys/dev/pci/if_ipw.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ipw.c,v 1.121 2017/10/26 15:00:28 mpi Exp $	*/
+/*	$OpenBSD: if_ipw.c,v 1.122 2018/04/26 12:50:07 pirofti Exp $	*/
 
 /*-
  * Copyright (c) 2004-2008
@@ -2024,9 +2024,6 @@ ipw_stop(struct ifnet *ifp, int disable)
 	for (i = 0; i < IPW_NTBD; i++)
 		ipw_release_sbd(sc, &sc->stbd_list[i]);
 
-	/* in case we were scanning, release the scan "lock" */
-	ic->ic_scan_lock = IEEE80211_SCAN_UNLOCKED;
-
 	ieee80211_new_state(ic, IEEE80211_S_INIT, -1);
 }
 
diff --git a/sys/dev/pci/if_iwi.c b/sys/dev/pci/if_iwi.c
index f60f9113333..2652cd5df5b 100644
--- a/sys/dev/pci/if_iwi.c
+++ b/sys/dev/pci/if_iwi.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_iwi.c,v 1.137 2017/10/26 15:00:28 mpi Exp $	*/
+/*	$OpenBSD: if_iwi.c,v 1.138 2018/04/26 12:50:07 pirofti Exp $	*/
 
 /*-
  * Copyright (c) 2004-2008
@@ -2291,9 +2291,6 @@ iwi_stop(struct ifnet *ifp, int disable)
 	ifp->if_flags &= ~IFF_RUNNING;
 	ifq_clr_oactive(&ifp->if_snd);
 
-	/* in case we were scanning, release the scan "lock" */
-	ic->ic_scan_lock = IEEE80211_SCAN_UNLOCKED;
-
 	ieee80211_new_state(ic, IEEE80211_S_INIT, -1);
 
 	iwi_stop_master(sc);
diff --git a/sys/dev/pci/if_iwm.c b/sys/dev/pci/if_iwm.c
index fa3c1c82cc8..150cb4dcef6 100644
--- a/sys/dev/pci/if_iwm.c
+++ b/sys/dev/pci/if_iwm.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_iwm.c,v 1.226 2018/02/28 14:39:35 stsp Exp $	*/
+/*	$OpenBSD: if_iwm.c,v 1.227 2018/04/26 12:50:07 pirofti Exp $	*/
 
 /*
  * Copyright (c) 2014, 2016 genua gmbh <info@genua.de>
@@ -6708,9 +6708,6 @@ iwm_stop(struct ifnet *ifp)
 		sc->sc_cmd_resp_pkt[i] = NULL;
 		sc->sc_cmd_resp_len[i] = 0;
 	}
-	if (ic->ic_scan_lock & IEEE80211_SCAN_REQUEST)
-		wakeup(&ic->ic_scan_lock);
-	ic->ic_scan_lock = IEEE80211_SCAN_UNLOCKED;
 	ifp->if_flags &= ~IFF_RUNNING;
 	ifq_clr_oactive(&ifp->if_snd);
 
diff --git a/sys/dev/pci/if_iwn.c b/sys/dev/pci/if_iwn.c
index d26fb6a5e64..fb9ac9434b8 100644
--- a/sys/dev/pci/if_iwn.c
+++ b/sys/dev/pci/if_iwn.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_iwn.c,v 1.201 2018/02/25 12:40:06 stsp Exp $	*/
+/*	$OpenBSD: if_iwn.c,v 1.202 2018/04/26 12:50:07 pirofti Exp $	*/
 
 /*-
  * Copyright (c) 2007-2010 Damien Bergamini <damien.bergamini@free.fr>
@@ -6633,11 +6633,6 @@ iwn_stop(struct ifnet *ifp, int disable)
 	ifp->if_flags &= ~IFF_RUNNING;
 	ifq_clr_oactive(&ifp->if_snd);
 
-	/* In case we were scanning, release the scan "lock". */
-	if (ic->ic_scan_lock & IEEE80211_SCAN_REQUEST)
-		wakeup(&ic->ic_scan_lock);
-	ic->ic_scan_lock = IEEE80211_SCAN_UNLOCKED;
-
 	ieee80211_new_state(ic, IEEE80211_S_INIT, -1);
 
 	/* Power OFF hardware. */
diff --git a/sys/dev/pci/if_wpi.c b/sys/dev/pci/if_wpi.c
index 214f1944ca3..e6b6330d717 100644
--- a/sys/dev/pci/if_wpi.c
+++ b/sys/dev/pci/if_wpi.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_wpi.c,v 1.142 2018/01/31 12:36:13 stsp Exp $	*/
+/*	$OpenBSD: if_wpi.c,v 1.143 2018/04/26 12:50:07 pirofti Exp $	*/
 
 /*-
  * Copyright (c) 2006-2008
@@ -3319,9 +3319,6 @@ wpi_stop(struct ifnet *ifp, int disable)
 	ifp->if_flags &= ~IFF_RUNNING;
 	ifq_clr_oactive(&ifp->if_snd);
 
-	/* In case we were scanning, release the scan "lock". */
-	ic->ic_scan_lock = IEEE80211_SCAN_UNLOCKED;
-
 	ieee80211_new_state(ic, IEEE80211_S_INIT, -1);
 
 	/* Power OFF hardware. */
diff --git a/sys/dev/usb/if_rsu.c b/sys/dev/usb/if_rsu.c
index fb70699874e..de65aaa91f5 100644
--- a/sys/dev/usb/if_rsu.c
+++ b/sys/dev/usb/if_rsu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_rsu.c,v 1.42 2018/01/31 12:36:13 stsp Exp $	*/
+/*	$OpenBSD: if_rsu.c,v 1.43 2018/04/26 12:50:07 pirofti Exp $	*/
 
 /*-
  * Copyright (c) 2010 Damien Bergamini <damien.bergamini@free.fr>
@@ -2313,9 +2313,6 @@ rsu_stop(struct ifnet *ifp)
 	ifp->if_flags &= ~IFF_RUNNING;
 	ifq_clr_oactive(&ifp->if_snd);
 
-	/* In case we were scanning, release the scan "lock". */
-	ic->ic_scan_lock = IEEE80211_SCAN_UNLOCKED;
-
 	s = splusb();
 	ieee80211_new_state(ic, IEEE80211_S_INIT, -1);
 	/* Wait for all async commands to complete. */
diff --git a/sys/net80211/ieee80211.c b/sys/net80211/ieee80211.c
index da43082d70c..6a00e5a0a22 100644
--- a/sys/net80211/ieee80211.c
+++ b/sys/net80211/ieee80211.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211.c,v 1.66 2018/04/20 09:40:36 jmatthew Exp $	*/
+/*	$OpenBSD: ieee80211.c,v 1.67 2018/04/26 12:50:07 pirofti Exp $	*/
 /*	$NetBSD: ieee80211.c,v 1.19 2004/06/06 05:45:29 dyoung Exp $	*/
 
 /*-
@@ -143,7 +143,6 @@ ieee80211_channel_init(struct ifnet *ifp)
 	if ((ic->ic_modecaps & (1<<ic->ic_curmode)) == 0)
 		ic->ic_curmode = IEEE80211_MODE_AUTO;
 	ic->ic_des_chan = IEEE80211_CHAN_ANYC;	/* any channel is ok */
-	ic->ic_scan_lock = IEEE80211_SCAN_UNLOCKED;
 }
 
 void
diff --git a/sys/net80211/ieee80211_ioctl.c b/sys/net80211/ieee80211_ioctl.c
index 4c8fb30f2b0..d934bb49a62 100644
--- a/sys/net80211/ieee80211_ioctl.c
+++ b/sys/net80211/ieee80211_ioctl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211_ioctl.c,v 1.59 2018/02/19 08:59:52 mpi Exp $	*/
+/*	$OpenBSD: ieee80211_ioctl.c,v 1.60 2018/04/26 12:50:07 pirofti Exp $	*/
 /*	$NetBSD: ieee80211_ioctl.c,v 1.15 2004/05/06 02:58:16 dyoung Exp $	*/
 
 /*-
@@ -670,42 +670,7 @@ ieee80211_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 			ifp->if_mtu = ifr->ifr_mtu;
 		break;
 	case SIOCS80211SCAN:
-		if ((error = suser(curproc)) != 0)
-			break;
-#ifndef IEEE80211_STA_ONLY
-		if (ic->ic_opmode == IEEE80211_M_HOSTAP)
-			break;
-#endif
-		if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) !=
-		    (IFF_UP | IFF_RUNNING)) {
-			error = ENETDOWN;
-			break;
-		}
-		if ((ic->ic_scan_lock & IEEE80211_SCAN_REQUEST) == 0) {
-			if (ic->ic_scan_lock & IEEE80211_SCAN_LOCKED)
-				ic->ic_scan_lock |= IEEE80211_SCAN_RESUME;
-			ic->ic_scan_lock |= IEEE80211_SCAN_REQUEST;
-			if (ic->ic_state != IEEE80211_S_SCAN) {
-				ieee80211_clean_cached(ic);
-				if (ic->ic_opmode == IEEE80211_M_STA &&
-				    ic->ic_state == IEEE80211_S_RUN &&
-				    IFM_MODE(ic->ic_media.ifm_cur->ifm_media)
-				    == IFM_AUTO) {
-					/* 
-					 * We're already associated to an AP.
-					 * Make the scanning loop start off in
-					 * auto mode so all supported bands
-					 * get scanned.
-					 */
-					ieee80211_setmode(ic,
-					    IEEE80211_MODE_AUTO);
-				}
-				ieee80211_new_state(ic, IEEE80211_S_SCAN, -1);
-			}
-		}
-		/* Let the userspace process wait for completion */
-		error = tsleep(&ic->ic_scan_lock, PCATCH, "80211scan",
-		    hz * IEEE80211_SCAN_TIMEOUT);
+		/* Disabled. SIOCG80211ALLNODES is enough. */
 		break;
 	case SIOCG80211NODE:
 		nr = (struct ieee80211_nodereq *)data;
@@ -769,6 +734,12 @@ ieee80211_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 		break;
 #endif
 	case SIOCG80211ALLNODES:
+		if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) !=
+		    (IFF_UP | IFF_RUNNING)) {
+			error = ENETDOWN;
+			break;
+		}
+
 		na = (struct ieee80211_nodereq_all *)data;
 		na->na_nodes = i = 0;
 		ni = RBT_MIN(ieee80211_tree, &ic->ic_tree);
diff --git a/sys/net80211/ieee80211_node.c b/sys/net80211/ieee80211_node.c
index ae923d5beef..2f911dc5325 100644
--- a/sys/net80211/ieee80211_node.c
+++ b/sys/net80211/ieee80211_node.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211_node.c,v 1.126 2018/02/06 22:14:52 phessler Exp $	*/
+/*	$OpenBSD: ieee80211_node.c,v 1.127 2018/04/26 12:50:07 pirofti Exp $	*/
 /*	$NetBSD: ieee80211_node.c,v 1.14 2004/05/09 09:18:47 dyoung Exp $	*/
 
 /*-
@@ -245,10 +245,6 @@ ieee80211_begin_scan(struct ifnet *ifp)
 {
 	struct ieee80211com *ic = (void *)ifp;
 
-	if (ic->ic_scan_lock & IEEE80211_SCAN_LOCKED)
-		return;
-	ic->ic_scan_lock |= IEEE80211_SCAN_LOCKED;
-
 	/*
 	 * In all but hostap mode scanning starts off in
 	 * an active mode before switching to passive.
@@ -709,7 +705,7 @@ ieee80211_end_scan(struct ifnet *ifp)
 					break;
 		}
 		ieee80211_create_ibss(ic, &ic->ic_channels[i]);
-		goto wakeup;
+		return;
 	}
 #endif
 	if (ni == NULL) {
@@ -721,7 +717,7 @@ ieee80211_end_scan(struct ifnet *ifp)
 		    (ic->ic_flags & IEEE80211_F_IBSSON) &&
 		    ic->ic_des_esslen != 0) {
 			ieee80211_create_ibss(ic, ic->ic_ibss_chan);
-			goto wakeup;
+			return;
 		}
 #endif
 		/*
@@ -735,14 +731,8 @@ ieee80211_end_scan(struct ifnet *ifp)
 		 */
 		if (ieee80211_next_mode(ifp) == IEEE80211_MODE_AUTO ||
 		    (ic->ic_caps & IEEE80211_C_SCANALLBAND)) {
-			if (ic->ic_scan_lock & IEEE80211_SCAN_REQUEST &&
-			    ic->ic_scan_lock & IEEE80211_SCAN_RESUME) {
-				ic->ic_scan_lock = IEEE80211_SCAN_LOCKED;
-				/* Return from a user-initiated scan. */
-				wakeup(&ic->ic_scan_lock);
-			} else if (ic->ic_scan_lock & IEEE80211_SCAN_REQUEST)
-				goto wakeup;
 			ic->ic_scan_count++;
+			return;
 		}
 
 		/*
@@ -819,13 +809,13 @@ ieee80211_end_scan(struct ifnet *ifp)
 			if (ic->ic_bgscan_fail < IEEE80211_BGSCAN_FAIL_MAX)
 				ic->ic_bgscan_fail++;
 			ic->ic_flags &= ~IEEE80211_F_BGSCAN;
-			goto wakeup;
+			return;
 		}
 	
 		arg = malloc(sizeof(*arg), M_DEVBUF, M_NOWAIT | M_ZERO);
 		if (arg == NULL) {
 			ic->ic_flags &= ~IEEE80211_F_BGSCAN;
-			goto wakeup;
+			return;
 		}
 
 		ic->ic_bgscan_fail = 0;
@@ -838,7 +828,7 @@ ieee80211_end_scan(struct ifnet *ifp)
 		    IEEE80211_FC0_SUBTYPE_DEAUTH,
 		    IEEE80211_REASON_AUTH_LEAVE) != 0) {
 			ic->ic_flags &= ~IEEE80211_F_BGSCAN;
-			goto wakeup;
+			return;
 		}
 
 		/* Prevent dispatch of additional data frames to hardware. */
@@ -854,19 +844,11 @@ ieee80211_end_scan(struct ifnet *ifp)
 		ic->ic_bss->ni_unref_arg_size = sizeof(*arg);
 		ic->ic_bss->ni_unref_cb = ieee80211_node_switch_bss;
 		/* F_BGSCAN flag gets cleared in ieee80211_node_join_bss(). */
-		goto wakeup;
+		return;
 	} else if (selbs == NULL)
 		goto notfound;
 
 	ieee80211_node_join_bss(ic, selbs);
-
- wakeup:
-	if (ic->ic_scan_lock & IEEE80211_SCAN_REQUEST) {
-		/* Return from a user-initiated scan. */
-		wakeup(&ic->ic_scan_lock);
-	}
-
-	ic->ic_scan_lock = IEEE80211_SCAN_UNLOCKED;
 }
 
 /*
diff --git a/sys/net80211/ieee80211_var.h b/sys/net80211/ieee80211_var.h
index 5b9e11179dd..63bedcef508 100644
--- a/sys/net80211/ieee80211_var.h
+++ b/sys/net80211/ieee80211_var.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211_var.h,v 1.84 2018/02/05 08:44:13 stsp Exp $	*/
+/*	$OpenBSD: ieee80211_var.h,v 1.85 2018/04/26 12:50:07 pirofti Exp $	*/
 /*	$NetBSD: ieee80211_var.h,v 1.7 2004/05/06 03:07:10 dyoung Exp $	*/
 
 /*-
@@ -240,7 +240,6 @@ struct ieee80211com {
 	u_char			ic_chan_scan[howmany(IEEE80211_CHAN_MAX,NBBY)];
 	struct mbuf_queue	ic_mgtq;
 	struct mbuf_queue	ic_pwrsaveq;
-	u_int			ic_scan_lock;	/* user-initiated scan */
 	u_int8_t		ic_scan_count;	/* count scans */
 	u_int32_t		ic_flags;	/* state flags */
 	u_int32_t		ic_xflags;	/* more flags */