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authorLuis R. Rodriguez <lrodriguez@atheros.com>2009-01-08 04:43:36 +0300
committerJohn W. Linville <linville@tuxdriver.com>2009-01-17 01:08:24 +0300
commit0c7dc45d21de6ae212b5ccb7cdff5beff795ccf0 (patch)
treed8b8f72105da3cd3dc07e9499ddc0da7a61d75f6 /net
parenta92a3ce72483d7f0902dff8a3be8cdcee215a37c (diff)
downloadlinux-0c7dc45d21de6ae212b5ccb7cdff5beff795ccf0.tar.xz
cfg80211: Fix regression with 11d on bands
This fixes a regression on disallowing bands introduced with the new 802.11d support. The issue is that IEEE-802.11 allows APs to send a subset of what a country regulatory domain defines. This was clarified in this document: http://tinyurl.com/11d-clarification As such it is possible, and this is what is done in practice, that a single band 2.4 GHz AP will only send 2.4 GHz band regulatory information through the 802.11 country information element and then the current intersection with what CRDA provided yields a regulatory domain with no 5 GHz information -- even though that country may actually allow 5 GHz operation. We correct this by only applying the intersection rules on a channel if the the intersection yields a regulatory rule on the same band the channel is on. Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net')
-rw-r--r--net/wireless/reg.c82
1 files changed, 79 insertions, 3 deletions
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index af805b0e1579..5f6d20d98eeb 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -421,6 +421,31 @@ static u32 freq_max_bandwidth(const struct ieee80211_freq_range *freq_range,
return 0;
}
+/**
+ * freq_in_rule_band - tells us if a frequency is in a frequency band
+ * @freq_range: frequency rule we want to query
+ * @freq_khz: frequency we are inquiring about
+ *
+ * This lets us know if a specific frequency rule is or is not relevant to
+ * a specific frequency's band. Bands are device specific and artificial
+ * definitions (the "2.4 GHz band" and the "5 GHz band"), however it is
+ * safe for now to assume that a frequency rule should not be part of a
+ * frequency's band if the start freq or end freq are off by more than 2 GHz.
+ * This resolution can be lowered and should be considered as we add
+ * regulatory rule support for other "bands".
+ **/
+static bool freq_in_rule_band(const struct ieee80211_freq_range *freq_range,
+ u32 freq_khz)
+{
+#define ONE_GHZ_IN_KHZ 1000000
+ if (abs(freq_khz - freq_range->start_freq_khz) <= (2 * ONE_GHZ_IN_KHZ))
+ return true;
+ if (abs(freq_khz - freq_range->end_freq_khz) <= (2 * ONE_GHZ_IN_KHZ))
+ return true;
+ return false;
+#undef ONE_GHZ_IN_KHZ
+}
+
/* Converts a country IE to a regulatory domain. A regulatory domain
* structure has a lot of information which the IE doesn't yet have,
* so for the other values we use upper max values as we will intersect
@@ -748,12 +773,23 @@ static u32 map_regdom_flags(u32 rd_flags)
* this value to the maximum allowed bandwidth.
* @reg_rule: the regulatory rule which we have for this frequency
*
- * Use this function to get the regulatory rule for a specific frequency.
+ * Use this function to get the regulatory rule for a specific frequency on
+ * a given wireless device. If the device has a specific regulatory domain
+ * it wants to follow we respect that unless a country IE has been received
+ * and processed already.
+ *
+ * Returns 0 if it was able to find a valid regulatory rule which does
+ * apply to the given center_freq otherwise it returns non-zero. It will
+ * also return -ERANGE if we determine the given center_freq does not even have
+ * a regulatory rule for a frequency range in the center_freq's band. See
+ * freq_in_rule_band() for our current definition of a band -- this is purely
+ * subjective and right now its 802.11 specific.
*/
static int freq_reg_info(u32 center_freq, u32 *bandwidth,
const struct ieee80211_reg_rule **reg_rule)
{
int i;
+ bool band_rule_found = false;
u32 max_bandwidth = 0;
if (!cfg80211_regdomain)
@@ -767,7 +803,15 @@ static int freq_reg_info(u32 center_freq, u32 *bandwidth,
rr = &cfg80211_regdomain->reg_rules[i];
fr = &rr->freq_range;
pr = &rr->power_rule;
+
+ /* We only need to know if one frequency rule was
+ * was in center_freq's band, that's enough, so lets
+ * not overwrite it once found */
+ if (!band_rule_found)
+ band_rule_found = freq_in_rule_band(fr, center_freq);
+
max_bandwidth = freq_max_bandwidth(fr, center_freq);
+
if (max_bandwidth && *bandwidth <= max_bandwidth) {
*reg_rule = rr;
*bandwidth = max_bandwidth;
@@ -775,6 +819,9 @@ static int freq_reg_info(u32 center_freq, u32 *bandwidth,
}
}
+ if (!band_rule_found)
+ return -ERANGE;
+
return !max_bandwidth;
}
@@ -799,8 +846,37 @@ static void handle_channel(struct wiphy *wiphy, enum ieee80211_band band,
&max_bandwidth, &reg_rule);
if (r) {
- flags |= IEEE80211_CHAN_DISABLED;
- chan->flags = flags;
+ /* This means no regulatory rule was found in the country IE
+ * with a frequency range on the center_freq's band, since
+ * IEEE-802.11 allows for a country IE to have a subset of the
+ * regulatory information provided in a country we ignore
+ * disabling the channel unless at least one reg rule was
+ * found on the center_freq's band. For details see this
+ * clarification:
+ *
+ * http://tinyurl.com/11d-clarification
+ */
+ if (r == -ERANGE &&
+ last_request->initiator == REGDOM_SET_BY_COUNTRY_IE) {
+#ifdef CONFIG_CFG80211_REG_DEBUG
+ printk(KERN_DEBUG "cfg80211: Leaving channel %d MHz "
+ "intact on %s - no rule found in band on "
+ "Country IE\n",
+ chan->center_freq, wiphy_name(wiphy));
+#endif
+ } else {
+ /* In this case we know the country IE has at least one reg rule
+ * for the band so we respect its band definitions */
+#ifdef CONFIG_CFG80211_REG_DEBUG
+ if (last_request->initiator == REGDOM_SET_BY_COUNTRY_IE)
+ printk(KERN_DEBUG "cfg80211: Disabling "
+ "channel %d MHz on %s due to "
+ "Country IE\n",
+ chan->center_freq, wiphy_name(wiphy));
+#endif
+ flags |= IEEE80211_CHAN_DISABLED;
+ chan->flags = flags;
+ }
return;
}