On Sat, Jan 16, 2010 at 01:55:21AM -0800, Benoit PAPILLAULT wrote:
> Luis R. Rodriguez a écrit :
> > In practice APs do not send country IE channel triplets for channels
> > the AP is not operating on and if they were to do so they would have
> > to use the regulatory extension which we currently do not process.
> > No AP has been seen in practice that does this though so just drop
> > those country IEs.
> >
> > Additionally it has been noted the first series of country IE
> > channels triplets are specific to the band the AP sends. Propagate
> > the band on which the country IE was found on reject the country
> > IE then if the triplets are ever oustide of the band.
> >
> > Although we now won't process country IE information with multiple
> > band information we leave the intersection work as is as it is
> > technically possible for someone to want to eventually process these
> > type of country IEs with regulatory extensions.
> >
> > Cc: Jouni Malinen <jouni.malinen@xxxxxxxxxxx>
> > Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx>
> > ---
> >
> > This goes out tested now.
> >
> > net/wireless/reg.c | 74 ++++++++++++++++++++++++++++++++++++++--------------
> > net/wireless/reg.h | 11 +++++++
> > net/wireless/sme.c | 1 +
> > 3 files changed, 66 insertions(+), 20 deletions(-)
> >
> > diff --git a/net/wireless/reg.c b/net/wireless/reg.c
> > index 5b03ca7..7242121 100644
> > --- a/net/wireless/reg.c
> > +++ b/net/wireless/reg.c
> > @@ -485,6 +485,34 @@ static bool freq_in_rule_band(const struct ieee80211_freq_range *freq_range,
> > }
> >
> > /*
> > + * This is a work around for sanity checking ieee80211_channel_to_frequency()'s
> > + * work. ieee80211_channel_to_frequency() can for example currently provide a
> > + * 2 GHz channel when in fact a 5 GHz channel was desired. An example would be
> > + * an AP providing channel 8 on a country IE triplet when it sent this on the
> > + * 5 GHz band, that channel is designed to be channel 8 on 5 GHz, not a 2 GHz
> > + * channel.
> > + *
> > + * This can be removed once ieee80211_channel_to_frequency() takes in a band.
> > + */
> > +static bool chan_in_band(int chan, enum ieee80211_band band)
> > +{
> > + int center_freq = ieee80211_channel_to_frequency(chan);
> > +
> > + switch (band) {
> > + case IEEE80211_BAND_2GHZ:
> > + if (center_freq <= 2484)
> > + return true;
> > + return false;
> > + case IEEE80211_BAND_5GHZ:
> > + if (center_freq >= 5005)
> > + return true;
> > + return false;
> > + default:
> > + return false;
> > + }
> > +}
> > +
> > +/*
> > * Some APs may send a country IE triplet for each channel they
> > * support and while this is completely overkill and silly we still
> > * need to support it. We avoid making a single rule for each channel
> > @@ -532,7 +560,8 @@ static bool freq_in_rule_band(const struct ieee80211_freq_range *freq_range,
> > * Returns 0 if the IE has been found to be invalid in the middle
> > * somewhere.
> > */
> > -static int max_subband_chan(int orig_cur_chan,
> > +static int max_subband_chan(enum ieee80211_band band,
> > + int orig_cur_chan,
> > int orig_end_channel,
> > s8 orig_max_power,
> > u8 **country_ie,
> > @@ -541,7 +570,6 @@ static int max_subband_chan(int orig_cur_chan,
> > u8 *triplets_start = *country_ie;
> > u8 len_at_triplet = *country_ie_len;
> > int end_subband_chan = orig_end_channel;
> > - enum ieee80211_band band;
> >
> > /*
> > * We'll deal with padding for the caller unless
> > @@ -557,17 +585,14 @@ static int max_subband_chan(int orig_cur_chan,
> > *country_ie += 3;
> > *country_ie_len -= 3;
> >
> > - if (orig_cur_chan <= 14)
> > - band = IEEE80211_BAND_2GHZ;
> > - else
> > - band = IEEE80211_BAND_5GHZ;
> > + if (!chan_in_band(orig_cur_chan, band))
> > + return 0;
> >
> > while (*country_ie_len >= 3) {
> > int end_channel = 0;
> > struct ieee80211_country_ie_triplet *triplet =
> > (struct ieee80211_country_ie_triplet *) *country_ie;
> > int cur_channel = 0, next_expected_chan;
> > - enum ieee80211_band next_band = IEEE80211_BAND_2GHZ;
> >
> > /* means last triplet is completely unrelated to this one */
> > if (triplet->ext.reg_extension_id >=
> > @@ -592,6 +617,9 @@ static int max_subband_chan(int orig_cur_chan,
> > if (triplet->chans.first_channel <= end_subband_chan)
> > return 0;
> >
> > + if (!chan_in_band(triplet->chans.first_channel, band))
> > + return 0;
> > +
> > /* 2 GHz */
> > if (triplet->chans.first_channel <= 14) {
> > end_channel = triplet->chans.first_channel +
> > @@ -600,14 +628,10 @@ static int max_subband_chan(int orig_cur_chan,
> > else {
> > end_channel = triplet->chans.first_channel +
> > (4 * (triplet->chans.num_channels - 1));
> > - next_band = IEEE80211_BAND_5GHZ;
> > }
> >
> > - if (band != next_band) {
> > - *country_ie -= 3;
> > - *country_ie_len += 3;
> > - break;
> > - }
> > + if (!chan_in_band(end_channel, band))
> > + return 0;
> >
> > if (orig_max_power != triplet->chans.max_power) {
> > *country_ie -= 3;
> > @@ -666,6 +690,7 @@ static int max_subband_chan(int orig_cur_chan,
> > * with our userspace regulatory agent to get lower bounds.
> > */
> > static struct ieee80211_regdomain *country_ie_2_rd(
> > + enum ieee80211_band band,
> > u8 *country_ie,
> > u8 country_ie_len,
> > u32 *checksum)
> > @@ -743,8 +768,11 @@ static struct ieee80211_regdomain *country_ie_2_rd(
> > if (triplet->chans.num_channels == 0)
> > return NULL;
> >
> > + if (!chan_in_band(triplet->chans.first_channel, band))
> > + return NULL;
> > +
> > /* 2 GHz */
> > - if (triplet->chans.first_channel <= 14)
> > + if (band == IEEE80211_BAND_2GHZ)
> > end_channel = triplet->chans.first_channel +
> > triplet->chans.num_channels - 1;
> > else
> > @@ -767,7 +795,8 @@ static struct ieee80211_regdomain *country_ie_2_rd(
> > * or for whatever reason sends triplets with multiple channels
> > * separated when in fact they should be together.
> > */
> > - end_channel = max_subband_chan(cur_channel,
> > + end_channel = max_subband_chan(band,
> > + cur_channel,
> > end_channel,
> > triplet->chans.max_power,
> > &country_ie,
> > @@ -775,6 +804,9 @@ static struct ieee80211_regdomain *country_ie_2_rd(
> > if (!end_channel)
> > return NULL;
> >
> > + if (!chan_in_band(end_channel, band))
> > + return NULL;
> > +
> > cur_sub_max_channel = end_channel;
> >
> > /* Basic sanity check */
> > @@ -867,14 +899,15 @@ static struct ieee80211_regdomain *country_ie_2_rd(
> > reg_rule->flags = flags;
> >
> > /* 2 GHz */
> > - if (triplet->chans.first_channel <= 14)
> > + if (band == IEEE80211_BAND_2GHZ)
> > end_channel = triplet->chans.first_channel +
> > triplet->chans.num_channels -1;
> > else
> > end_channel = triplet->chans.first_channel +
> > (4 * (triplet->chans.num_channels - 1));
> >
> > - end_channel = max_subband_chan(triplet->chans.first_channel,
> > + end_channel = max_subband_chan(band,
> > + triplet->chans.first_channel,
> > end_channel,
> > triplet->chans.max_power,
> > &country_ie,
> > @@ -1981,8 +2014,9 @@ static bool reg_same_country_ie_hint(struct wiphy *wiphy,
> > * therefore cannot iterate over the rdev list here.
> > */
> > void regulatory_hint_11d(struct wiphy *wiphy,
> > - u8 *country_ie,
> > - u8 country_ie_len)
> > + enum ieee80211_band band,
> > + u8 *country_ie,
> > + u8 country_ie_len)
> > {
> > struct ieee80211_regdomain *rd = NULL;
> > char alpha2[2];
> > @@ -2028,7 +2062,7 @@ void regulatory_hint_11d(struct wiphy *wiphy,
> > wiphy_idx_valid(last_request->wiphy_idx)))
> > goto out;
> >
> > - rd = country_ie_2_rd(country_ie, country_ie_len, &checksum);
> > + rd = country_ie_2_rd(band, country_ie, country_ie_len, &checksum);
> > if (!rd) {
> > REG_DBG_PRINT("cfg80211: Ignoring bogus country IE\n");
> > goto out;
> > diff --git a/net/wireless/reg.h b/net/wireless/reg.h
> > index 3362c7c..3018508 100644
> > --- a/net/wireless/reg.h
> > +++ b/net/wireless/reg.h
> > @@ -41,14 +41,25 @@ int regulatory_hint_found_beacon(struct wiphy *wiphy,
> > * regulatory_hint_11d - hints a country IE as a regulatory domain
> > * @wiphy: the wireless device giving the hint (used only for reporting
> > * conflicts)
> > + * @band: the band on which the country IE was received on. This determines
> > + * the band we'll process the country IE channel triplets for.
> > * @country_ie: pointer to the country IE
> > * @country_ie_len: length of the country IE
> > *
> > * We will intersect the rd with the what CRDA tells us should apply
> > * for the alpha2 this country IE belongs to, this prevents APs from
> > * sending us incorrect or outdated information against a country.
> > + *
> > + * The AP is expected to provide Country IE channel triplets for the
> > + * band it is on. It is technically possible for APs to send channel
> > + * country IE triplets even for channels outside of the band they are
> > + * in but for that they would have to use the regulatory extension
> > + * in combination with a triplet but this behaviour is currently
> > + * not observed. For this reason if a triplet is seen with channel
> > + * information for a band the BSS is not present in it will be ignored.
> > */
> > void regulatory_hint_11d(struct wiphy *wiphy,
> > + enum ieee80211_band band,
> > u8 *country_ie,
> > u8 country_ie_len);
> >
> > diff --git a/net/wireless/sme.c b/net/wireless/sme.c
> > index 2333d78..2ce5e16 100644
> > --- a/net/wireless/sme.c
> > +++ b/net/wireless/sme.c
> > @@ -454,6 +454,7 @@ void __cfg80211_connect_result(struct net_device *dev, const u8 *bssid,
> > * - and country_ie[1] which is the IE length
> > */
> > regulatory_hint_11d(wdev->wiphy,
> > + bss->channel->band,
> > country_ie + 2,
> > country_ie[1]);
> > }
> >
>
> I think the channel conversion could be improved (we could directly
> compare the channel number with valid values as defined in
> IEEE802.11-2007 without converting them to a center frequency), but it
> could be done in a latter patch. So far :
Well so channel conversion really needs more work than that
actually, it should eventually address regulatory extension
stuff, which I've been avoiding for long now.
Luis
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