Fix an undefined behaviour if the desired ratectl algo is not available.

This can happen if the algos are built as modules but are not loaded. If
the selected ratectl algo is not available, try to load it (The load
module functions does nothing currently). Add a dummy ratectl algo which
always selects the first available rate. Use that one if the desired algo
is not available.

MFC after:	1 week

3 files changed, 133 insertions, 1 deletions

diff --git a/sys/net80211/ieee80211_ratectl.c b/sys/net80211/ieee80211_ratectl.c
index 2e8eb7e..ea3d8d4 100644
--- a/sys/net80211/ieee80211_ratectl.c
+++ b/sys/net80211/ieee80211_ratectl.c
@@ -39,6 +39,14 @@ __FBSDID("$FreeBSD$");
 
 static const struct ieee80211_ratectl *ratectls[IEEE80211_RATECTL_MAX];
 
+static const char *ratectl_modnames[IEEE80211_RATECTL_MAX] = {
+	[IEEE80211_RATECTL_AMRR]	= "wlan_amrr",
+	[IEEE80211_RATECTL_RSSADAPT]	= "wlan_rssadapt",
+	[IEEE80211_RATECTL_ONOE]	= "wlan_onoe",
+	[IEEE80211_RATECTL_SAMPLE]	= "wlan_sample",
+	[IEEE80211_RATECTL_NONE]	= "wlan_none",
+};
+
 MALLOC_DEFINE(M_80211_RATECTL, "80211ratectl", "802.11 rate control");
 
 void
@@ -62,5 +70,15 @@ ieee80211_ratectl_set(struct ieee80211vap *vap, int type)
 {
 	if (type >= IEEE80211_RATECTL_MAX)
 		return;
+	if (ratectls[type] == NULL) {
+		ieee80211_load_module(ratectl_modnames[type]);
+		if (ratectls[type] == NULL) {
+			IEEE80211_DPRINTF(vap, IEEE80211_MSG_RATECTL,
+			    "%s: unable to load algo %u, module %s\n",
+			    __func__, type, ratectl_modnames[type]);
+			vap->iv_rate = ratectls[IEEE80211_RATECTL_NONE];
+			return;
+		}
+	}
 	vap->iv_rate = ratectls[type];
 }
diff --git a/sys/net80211/ieee80211_ratectl.h b/sys/net80211/ieee80211_ratectl.h
index 73b4f32..87b2698 100644
--- a/sys/net80211/ieee80211_ratectl.h
+++ b/sys/net80211/ieee80211_ratectl.h
@@ -26,10 +26,11 @@
  */
 
 enum ieee80211_ratealgs {
-	IEEE80211_RATECTL_AMRR 		= 0,
+	IEEE80211_RATECTL_AMRR		= 0,
 	IEEE80211_RATECTL_RSSADAPT	= 1,
 	IEEE80211_RATECTL_ONOE		= 2,
 	IEEE80211_RATECTL_SAMPLE	= 3,
+	IEEE80211_RATECTL_NONE		= 4,
 	IEEE80211_RATECTL_MAX
 };
 
diff --git a/sys/net80211/ieee80211_ratectl_none.c b/sys/net80211/ieee80211_ratectl_none.c
new file mode 100644
index 0000000..0979e9d
--- /dev/null
+++ b/sys/net80211/ieee80211_ratectl_none.c
@@ -0,0 +1,113 @@
+/*-
+ * Copyright (c) 2010 Bernhard Schmidt <bschmidt@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "opt_wlan.h"
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/socket.h>
+#include <sys/sysctl.h>
+
+#include <net/if.h>
+#include <net/if_media.h>
+
+#ifdef INET
+#include <netinet/in.h>
+#include <netinet/if_ether.h>
+#endif
+
+#include <net80211/ieee80211_var.h>
+#include <net80211/ieee80211_ratectl.h>
+
+static void
+none_init(struct ieee80211vap *vap)
+{
+}
+
+static void
+none_deinit(struct ieee80211vap *vap)
+{
+	free(vap->iv_rs, M_80211_RATECTL);
+}
+
+static void
+none_node_init(struct ieee80211_node *ni)
+{
+}
+
+static void
+none_node_deinit(struct ieee80211_node *ni)
+{
+}
+
+static int
+none_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
+{
+	int rix = 0;
+
+	ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
+	return rix;
+}
+
+static void
+none_tx_complete(const struct ieee80211vap *vap,
+    const struct ieee80211_node *ni, int ok,
+    void *arg1, void *arg2 __unused)
+{
+}
+
+static void
+none_tx_update(const struct ieee80211vap *vap, const struct ieee80211_node *ni,
+    void *arg1, void *arg2, void *arg3)
+{
+}
+
+static void
+none_setinterval(const struct ieee80211vap *vap, int msecs)
+{
+}
+
+/* number of references from net80211 layer */
+static	int nrefs = 0;
+
+static const struct ieee80211_ratectl none = {
+	.ir_name	= "none",
+	.ir_attach	= NULL,
+	.ir_detach	= NULL,
+	.ir_init	= none_init,
+	.ir_deinit	= none_deinit,
+	.ir_node_init	= none_node_init,
+	.ir_node_deinit	= none_node_deinit,
+	.ir_rate	= none_rate,
+	.ir_tx_complete	= none_tx_complete,
+	.ir_tx_update	= none_tx_update,
+	.ir_setinterval	= none_setinterval,
+};
+IEEE80211_RATECTL_MODULE(ratectl_none, 1);
+IEEE80211_RATECTL_ALG(none, IEEE80211_RATECTL_NONE, none);