On Wed, 2009-01-07 at 17:43 -0800, Luis R. Rodriguez wrote: > 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 I think you should give the full link, regardless of how long it is. It's just on the 802 docserver, no? > 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. Seems sane to me. > Signed-off-by: Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx> Acked-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> > --- > net/wireless/reg.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 files changed, 75 insertions(+), 2 deletions(-) > > diff --git a/net/wireless/reg.c b/net/wireless/reg.c > index 3d56a1d..bea98ed 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 > @@ -753,11 +778,19 @@ static u32 map_regdom_flags(u32 rd_flags) > * 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(struct wiphy *wiphy, u32 center_freq, u32 *bandwidth, > const struct ieee80211_reg_rule **reg_rule) > { > int i; > + bool band_rule_found = false; > const struct ieee80211_regdomain *regd; > u32 max_bandwidth = 0; > > @@ -780,7 +813,15 @@ static int freq_reg_info(struct wiphy *wiphy, u32 center_freq, u32 *bandwidth, > rr = ®d->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; > @@ -788,6 +829,9 @@ static int freq_reg_info(struct wiphy *wiphy, u32 center_freq, u32 *bandwidth, > } > } > > + if (!band_rule_found) > + return -ERANGE; > + > return !max_bandwidth; > } > > @@ -812,8 +856,37 @@ static void handle_channel(struct wiphy *wiphy, enum ieee80211_band band, > &max_bandwidth, ®_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; > } >
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