From a557c018f559886566a1d4f541d70edbcd50f37b Mon Sep 17 00:00:00 2001
From: Sam Leffler <sam@FreeBSD.org>
Date: Fri, 23 Nov 2007 05:57:20 +0000
Subject: [PATCH] add ieee80211_find_channel_byieee to lookup a channel by ieee
 channel #

Reviewed by:	thompsa
MFC after:	1 week
---
 sys/net80211/ieee80211.c     | 26 ++++++++++++++++++++++++++
 sys/net80211/ieee80211_var.h |  2 ++
 2 files changed, 28 insertions(+)

diff --git a/sys/net80211/ieee80211.c b/sys/net80211/ieee80211.c
index 33b83d591f22..38acb546fb6e 100644
--- a/sys/net80211/ieee80211.c
+++ b/sys/net80211/ieee80211.c
@@ -440,6 +440,32 @@ ieee80211_find_channel(struct ieee80211com *ic, int freq, int flags)
 	return NULL;
 }
 
+/*
+ * Locate a channel given a channel number+flags.  We cache
+ * the previous lookup to optimize switching between two
+ * channels--as happens with dynamic turbo.
+ */
+struct ieee80211_channel *
+ieee80211_find_channel_byieee(struct ieee80211com *ic, int ieee, int flags)
+{
+	struct ieee80211_channel *c;
+	int i;
+
+	flags &= IEEE80211_CHAN_ALLTURBO;
+	c = ic->ic_prevchan;
+	if (c != NULL && c->ic_ieee == ieee &&
+	    (c->ic_flags & IEEE80211_CHAN_ALLTURBO) == flags)
+		return c;
+	/* brute force search */
+	for (i = 0; i < ic->ic_nchans; i++) {
+		c = &ic->ic_channels[i];
+		if (c->ic_ieee == ieee &&
+		    (c->ic_flags & IEEE80211_CHAN_ALLTURBO) == flags)
+			return c;
+	}
+	return NULL;
+}
+
 static void
 addmedia(struct ieee80211com *ic, int mode, int mword)
 {
diff --git a/sys/net80211/ieee80211_var.h b/sys/net80211/ieee80211_var.h
index cd8403074b3d..3171ceff4794 100644
--- a/sys/net80211/ieee80211_var.h
+++ b/sys/net80211/ieee80211_var.h
@@ -422,6 +422,8 @@ int	ieee80211_chan2ieee(struct ieee80211com *,
 u_int	ieee80211_ieee2mhz(u_int, u_int);
 struct ieee80211_channel *ieee80211_find_channel(struct ieee80211com *,
 		int freq, int flags);
+struct ieee80211_channel *ieee80211_find_channel_byieee(struct ieee80211com *,
+		int ieee, int flags);
 int	ieee80211_setmode(struct ieee80211com *, enum ieee80211_phymode);
 enum ieee80211_phymode ieee80211_chan2mode(const struct ieee80211_channel *);