From 4d36ec58239eec44d77839ef6c25108efcbbb58c Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 27 Oct 2009 20:59:55 +0100 Subject: [PATCH] mac80211: split hardware scan by band There's currently a very odd bug in mac80211 -- a hardware scan that is done while the hardware is really operating on 2.4 GHz will include CCK rates in the probe request frame, even on 5 GHz (if the driver uses the mac80211 IEs). Vice versa, if the hardware is operating on 5 GHz the 2.4 GHz probe requests will not include CCK rates even though they should. Fix this by splitting up cfg80211 scan requests by band -- recalculating the IEs every time -- and requesting only per-band scans from the driver. Apparently this bug hasn't been a problem yet, but it is imaginable that some older access points get confused if confronted with such behaviour. Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/ieee80211_i.h | 8 ++-- net/mac80211/scan.c | 96 ++++++++++++++++++++++++++++---------- net/mac80211/util.c | 8 ++-- 3 files changed, 80 insertions(+), 32 deletions(-) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 60c2822802f0..6365079e6375 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -667,10 +667,9 @@ struct ieee80211_local { unsigned long scanning; struct cfg80211_ssid scan_ssid; struct cfg80211_scan_request *int_scan_req; - struct cfg80211_scan_request *scan_req; + struct cfg80211_scan_request *scan_req, *hw_scan_req; struct ieee80211_channel *scan_channel; - const u8 *orig_ies; - int orig_ies_len; + enum ieee80211_band hw_scan_band; int scan_channel_idx; int scan_ies_len; @@ -1050,7 +1049,8 @@ void ieee80211_send_auth(struct ieee80211_sub_if_data *sdata, u8 *extra, size_t extra_len, const u8 *bssid, const u8 *key, u8 key_len, u8 key_idx); int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer, - const u8 *ie, size_t ie_len); + const u8 *ie, size_t ie_len, + enum ieee80211_band band); void ieee80211_send_probe_req(struct ieee80211_sub_if_data *sdata, u8 *dst, const u8 *ssid, size_t ssid_len, const u8 *ie, size_t ie_len); diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index 1a643fe5250e..c46ac01e2a8f 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -187,6 +187,39 @@ ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) return RX_QUEUED; } +/* return false if no more work */ +static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) +{ + struct cfg80211_scan_request *req = local->scan_req; + enum ieee80211_band band; + int i, ielen, n_chans; + + do { + if (local->hw_scan_band == IEEE80211_NUM_BANDS) + return false; + + band = local->hw_scan_band; + n_chans = 0; + for (i = 0; i < req->n_channels; i++) { + if (req->channels[i]->band == band) { + local->hw_scan_req->channels[n_chans] = + req->channels[i]; + n_chans++; + } + } + + local->hw_scan_band++; + } while (!n_chans); + + local->hw_scan_req->n_channels = n_chans; + + ielen = ieee80211_build_preq_ies(local, (u8 *)local->hw_scan_req->ie, + req->ie, req->ie_len, band); + local->hw_scan_req->ie_len = ielen; + + return true; +} + /* * inform AP that we will go to sleep so that it will buffer the frames * while we scan @@ -247,13 +280,6 @@ static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data *sdata) } } -static void ieee80211_restore_scan_ies(struct ieee80211_local *local) -{ - kfree(local->scan_req->ie); - local->scan_req->ie = local->orig_ies; - local->scan_req->ie_len = local->orig_ies_len; -} - void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) { struct ieee80211_local *local = hw_to_local(hw); @@ -272,15 +298,22 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) return; } - if (test_bit(SCAN_HW_SCANNING, &local->scanning)) - ieee80211_restore_scan_ies(local); + was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); + if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) { + ieee80211_queue_delayed_work(&local->hw, + &local->scan_work, 0); + mutex_unlock(&local->scan_mtx); + return; + } + + kfree(local->hw_scan_req); + local->hw_scan_req = NULL; if (local->scan_req != local->int_scan_req) cfg80211_scan_done(local->scan_req, aborted); local->scan_req = NULL; local->scan_sdata = NULL; - was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning); local->scanning = 0; local->scan_channel = NULL; @@ -392,19 +425,23 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, if (local->ops->hw_scan) { u8 *ies; - int ielen; - ies = kmalloc(2 + IEEE80211_MAX_SSID_LEN + - local->scan_ies_len + req->ie_len, GFP_KERNEL); - if (!ies) + local->hw_scan_req = kmalloc( + sizeof(*local->hw_scan_req) + + req->n_channels * sizeof(req->channels[0]) + + 2 + IEEE80211_MAX_SSID_LEN + local->scan_ies_len + + req->ie_len, GFP_KERNEL); + if (!local->hw_scan_req) return -ENOMEM; - ielen = ieee80211_build_preq_ies(local, ies, - req->ie, req->ie_len); - local->orig_ies = req->ie; - local->orig_ies_len = req->ie_len; - req->ie = ies; - req->ie_len = ielen; + local->hw_scan_req->ssids = req->ssids; + local->hw_scan_req->n_ssids = req->n_ssids; + ies = (u8 *)local->hw_scan_req + + sizeof(*local->hw_scan_req) + + req->n_channels * sizeof(req->channels[0]); + local->hw_scan_req->ie = ies; + + local->hw_scan_band = 0; } local->scan_req = req; @@ -436,16 +473,17 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, ieee80211_recalc_idle(local); mutex_unlock(&local->scan_mtx); - if (local->ops->hw_scan) - rc = drv_hw_scan(local, local->scan_req); - else + if (local->ops->hw_scan) { + WARN_ON(!ieee80211_prep_hw_scan(local)); + rc = drv_hw_scan(local, local->hw_scan_req); + } else rc = ieee80211_start_sw_scan(local); mutex_lock(&local->scan_mtx); if (rc) { - if (local->ops->hw_scan) - ieee80211_restore_scan_ies(local); + kfree(local->hw_scan_req); + local->hw_scan_req = NULL; local->scanning = 0; ieee80211_recalc_idle(local); @@ -654,6 +692,14 @@ void ieee80211_scan_work(struct work_struct *work) return; } + if (local->hw_scan_req) { + int rc = drv_hw_scan(local, local->hw_scan_req); + mutex_unlock(&local->scan_mtx); + if (rc) + ieee80211_scan_completed(&local->hw, true); + return; + } + if (local->scan_req && !local->scanning) { struct cfg80211_scan_request *req = local->scan_req; int rc; diff --git a/net/mac80211/util.c b/net/mac80211/util.c index aeb65b3d2295..aedbaaa067e6 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -872,13 +872,14 @@ void ieee80211_send_auth(struct ieee80211_sub_if_data *sdata, } int ieee80211_build_preq_ies(struct ieee80211_local *local, u8 *buffer, - const u8 *ie, size_t ie_len) + const u8 *ie, size_t ie_len, + enum ieee80211_band band) { struct ieee80211_supported_band *sband; u8 *pos, *supp_rates_len, *esupp_rates_len = NULL; int i; - sband = local->hw.wiphy->bands[local->hw.conf.channel->band]; + sband = local->hw.wiphy->bands[band]; pos = buffer; @@ -966,7 +967,8 @@ void ieee80211_send_probe_req(struct ieee80211_sub_if_data *sdata, u8 *dst, memcpy(pos, ssid, ssid_len); pos += ssid_len; - skb_put(skb, ieee80211_build_preq_ies(local, pos, ie, ie_len)); + skb_put(skb, ieee80211_build_preq_ies(local, pos, ie, ie_len, + local->hw.conf.channel->band)); ieee80211_tx_skb(sdata, skb, 0); } -- 2.34.1