Luis R. Rodriguez a écrit :
On Sat, Jan 2, 2010 at 10:04 AM, Luis R. Rodriguez <mcgrof@xxxxxxxxx> wrote:
The issue should be that a frequency rule is being created for each
channel and although 40 MHz is being specified as max bandwidth
logistically only 20 MHz fits into that frequency rule. So what the
intersection needs to learn is how to merge rules or at least
understand them together. It may be easier to parse insaneIEs like the
ones your AP generates and re-generate one with actual ranges with
contiguity channels merged. And then use that one for the
intersection.
I have a patch in mind now for this, can you please apply this patch
on iw, scan and send me the output of the scan for your AP?
Luis
Here is the result for the said AP :
BSS 00:15:6d:e8:88:84 (on wlan0)
TSF: 627428313658 usec (7d, 06:17:08)
freq: 5180
beacon interval: 100
capability: ESS Privacy ShortSlotTime (0x0411)
signal: -76.00 dBm
last seen: 7604 ms ago
SSID: BEN_nsm5
Supported rates: 6.0* 9.0 12.0* 18.0 24.0* 36.0 48.0 54.0
DS Parameter set: channel 36
Country: FR Environment: Indoor only
Country IE triplets:
Channels [36 - 36]
Channels [40 - 40]
Channels [44 - 44]
Channels [48 - 48]
Channels [52 - 52]
Channels [56 - 56]
Channels [60 - 60]
Channels [64 - 64]
Channels [100 - 100]
Channels [104 - 104]
Channels [108 - 108]
Channels [112 - 112]
Channels [116 - 116]
Channels [120 - 120]
Channels [124 - 124]
Channels [128 - 128]
Channels [132 - 132]
Channels [136 - 136]
Channels [140 - 140]
Power constraint: 0 dB
RSN: * Version: 1
* Group cipher: CCMP
* Pairwise ciphers: CCMP
* Authentication suites: PSK
* Capabilities: (0x0000)
WMM: * Parameter version 1
* u-APSD
* BE: CW 15-1023, AIFSN 3
* BK: CW 15-1023, AIFSN 7
* VI: CW 7-15, AIFSN 2, TXOP 3008 usec
* VO: acm CW 3-7, AIFSN 2, TXOP 1504 usec
HT capabilities:
Capabilities: 0x4e
HT20/HT40
SM Power Save disabled
RX HT40 SGI
No RX STBC
Max AMSDU length: 7935 bytes
No DSSS/CCK HT40
Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
Minimum RX AMPDU time spacing: 1/2 usec (0x02)
HT RX MCS rate indexes supported: 0-15
HT TX MCS rate indexes are undefined
iw version 0.9.18-11-g89ea706-dirty
As a quick patch, I have commented 2 lines "bw_flags =
IEEE80211_CHAN_NO_HT40" in net/wireless/reg.c
I'll try to do a patch for the kernel that does the following action :
- parse the max_power field
- merge rules if the max_power field is the same for both rules
- use max_bandwidth_khz as a capability feature (ie it could be larger
than end_freq - start_freq)
- when trying to enable HT40, we might obey 2 reg rules (if they have
not been merge). In this case, we should intersect rules again.
Does this logic is fine?
Regards,
Benoit
commit b716fd7e8506eaff946f1429f048c258a03249ba
Author: Benoit Papillault <benoit.papillault@xxxxxxx>
Date: Thu Dec 31 10:58:14 2009 +0100
mac80211: quick fix to allow HT40 with a country IE
This patch fixes an issue to connect to an HT40 AP sending country IE for
all channels. Doing this way, each channel is 20 MHz only and as such, current
code would disallow HT40 operation. This can be seen in ht40allow_map
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 87ea60d..bb141c8 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -999,10 +999,10 @@ static void handle_channel(struct wiphy *wiphy, enum ieee80211_band band,
power_rule = ®_rule->power_rule;
freq_range = ®_rule->freq_range;
-
+ /*
if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(40))
bw_flags = IEEE80211_CHAN_NO_HT40;
-
+ */
if (last_request->initiator == NL80211_REGDOM_SET_BY_DRIVER &&
request_wiphy && request_wiphy == wiphy &&
request_wiphy->flags & WIPHY_FLAG_STRICT_REGULATORY) {
@@ -1318,10 +1318,10 @@ static void handle_channel_custom(struct wiphy *wiphy,
power_rule = ®_rule->power_rule;
freq_range = ®_rule->freq_range;
-
+ /*
if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(40))
bw_flags = IEEE80211_CHAN_NO_HT40;
-
+ */
chan->flags |= map_regdom_flags(reg_rule->flags) | bw_flags;
chan->max_antenna_gain = (int) MBI_TO_DBI(power_rule->max_antenna_gain);
chan->max_power = (int) MBM_TO_DBM(power_rule->max_eirp);
