diff options
Diffstat (limited to 'net/wireless')
| -rw-r--r-- | net/wireless/reg.c | 225 |
1 files changed, 221 insertions, 4 deletions
diff --git a/net/wireless/reg.c b/net/wireless/reg.c index 77d0bb6..a5c2d3a 100644 --- a/net/wireless/reg.c +++ b/net/wireless/reg.c @@ -485,6 +485,178 @@ static bool freq_in_rule_band(const struct ieee80211_freq_range *freq_range, } /* + * 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 + * though and to help us with this we use this helper to find the + * actual subband end channel. These type of country IE triplet + * scenerios are handled then, all yielding two regulaotry rules from + * parsing a country IE: + * + * [1] + * [2] + * [36] + * [40] + * + * [1] + * [2-4] + * [5-12] + * [36] + * [40-44] + * + * [1-4] + * [5-7] + * [36-44] + * [48-64] + * + * [36-36] + * [40-40] + * [44-44] + * [48-48] + * [52-52] + * [56-56] + * [60-60] + * [64-64] + * [100-100] + * [104-104] + * [108-108] + * [112-112] + * [116-116] + * [120-120] + * [124-124] + * [128-128] + * [132-132] + * [136-136] + * [140-140] + * + * Returns 0 if the IE has been found to be invalid in the middle + * somewhere. + */ +static int max_subband_chan(int orig_cur_chan, + int orig_end_channel, + s8 orig_max_power, + u8 **country_ie, + u8 *country_ie_len) +{ + 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 + * its not immediate and we don't process any channels + */ + if (*country_ie_len == 1) { + *country_ie += 1; + *country_ie_len -= 1; + return orig_end_channel; + } + + /* Move to the next triplet and then start search */ + *country_ie += 3; + *country_ie_len -= 3; + + if (orig_cur_chan <= 14) + band = IEEE80211_BAND_2GHZ; + else + band = IEEE80211_BAND_5GHZ; + + 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 >= + IEEE80211_COUNTRY_EXTENSION_ID) { + *country_ie -= 3; + *country_ie_len += 3; + break; + } + + if (triplet->chans.first_channel == 0) { + *country_ie += 1; + *country_ie_len -= 1; + if (*country_ie_len != 0) + return 0; + break; + } + + /* Monitonically increasing channel order */ + if (triplet->chans.first_channel <= end_subband_chan) + return 0; + + /* 2 GHz */ + if (triplet->chans.first_channel <= 14) { + end_channel = triplet->chans.first_channel + + triplet->chans.num_channels - 1; + } + 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 (orig_max_power != triplet->chans.max_power) { + *country_ie -= 3; + *country_ie_len += 3; + break; + } + + cur_channel = triplet->chans.first_channel; + + /* The key is finding the right next expected channel */ + if (band == IEEE80211_BAND_2GHZ) + next_expected_chan = end_subband_chan + 1; + else + next_expected_chan = end_subband_chan + 4; + + if (cur_channel != next_expected_chan) { + *country_ie -= 3; + *country_ie_len += 3; + break; + } + + end_subband_chan = end_channel; + + /* Move to the next one */ + *country_ie += 3; + *country_ie_len -= 3; + + /* + * Padding needs to be dealt with if we processed + * some channels. + */ + if (*country_ie_len == 1) { + *country_ie += 1; + *country_ie_len -= 1; + break; + } + + /* If seen, the IE is invalid */ + if (*country_ie_len == 2) + return 0; + } + + if (end_subband_chan == orig_end_channel) { + *country_ie = triplets_start; + *country_ie_len = len_at_triplet; + return orig_end_channel; + } + + return end_subband_chan; +} + +/* * 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 @@ -552,6 +724,19 @@ static struct ieee80211_regdomain *country_ie_2_rd( continue; } + /* + * APs can add padding to make length divisible + * by two, required by the spec. + */ + if (triplet->chans.first_channel == 0) { + country_ie++; + country_ie_len--; + /* This is expected to be at the very end only */ + if (country_ie_len != 0) + return NULL; + break; + } + /* 2 GHz */ if (triplet->chans.first_channel <= 14) end_channel = triplet->chans.first_channel + @@ -570,6 +755,20 @@ static struct ieee80211_regdomain *country_ie_2_rd( (4 * (triplet->chans.num_channels - 1)); cur_channel = triplet->chans.first_channel; + + /* + * Enhancement for APs that send a triplet for every channel + * 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, + triplet->chans.max_power, + &country_ie, + &country_ie_len); + if (!end_channel) + return NULL; + cur_sub_max_channel = end_channel; /* Basic sanity check */ @@ -600,10 +799,13 @@ static struct ieee80211_regdomain *country_ie_2_rd( last_sub_max_channel = cur_sub_max_channel; - country_ie += 3; - country_ie_len -= 3; num_rules++; + if (country_ie_len >= 3) { + country_ie += 3; + country_ie_len -= 3; + } + /* * Note: this is not a IEEE requirement but * simply a memory requirement @@ -646,6 +848,12 @@ static struct ieee80211_regdomain *country_ie_2_rd( continue; } + if (triplet->chans.first_channel == 0) { + country_ie++; + country_ie_len--; + break; + } + reg_rule = &rd->reg_rules[i]; freq_range = ®_rule->freq_range; power_rule = ®_rule->power_rule; @@ -660,6 +868,12 @@ static struct ieee80211_regdomain *country_ie_2_rd( end_channel = triplet->chans.first_channel + (4 * (triplet->chans.num_channels - 1)); + end_channel = max_subband_chan(triplet->chans.first_channel, + end_channel, + triplet->chans.max_power, + &country_ie, + &country_ie_len); + /* * The +10 is since the regulatory domain expects * the actual band edge, not the center of freq for @@ -682,10 +896,13 @@ static struct ieee80211_regdomain *country_ie_2_rd( power_rule->max_antenna_gain = DBI_TO_MBI(100); power_rule->max_eirp = DBM_TO_MBM(triplet->chans.max_power); - country_ie += 3; - country_ie_len -= 3; i++; + if (country_ie_len >= 3) { + country_ie += 3; + country_ie_len -= 3; + } + BUG_ON(i > NL80211_MAX_SUPP_REG_RULES); } |