Return-path: Received: from mail-pb0-f54.google.com ([209.85.160.54]:52939 "EHLO mail-pb0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751911Ab3AGWsp (ORCPT ); Mon, 7 Jan 2013 17:48:45 -0500 Received: by mail-pb0-f54.google.com with SMTP id wz12so10909619pbc.27 for ; Mon, 07 Jan 2013 14:48:44 -0800 (PST) From: Thomas Pedersen To: johannes@sipsolutions.net Cc: devel@lists.open80211s.org, linux-wireless@vger.kernel.org, Thomas Pedersen Subject: [PATCH v3] mac80211_hwsim: fix beacon timestamp and mactime Date: Mon, 7 Jan 2013 14:48:07 -0800 Message-Id: <1357598887-7617-1-git-send-email-thomas@cozybit.com> (sfid-20130107_234849_178452_5F7AA741) Sender: linux-wireless-owner@vger.kernel.org List-ID: Set the beacon timestamp once during "transmission" so the monitor interface also gets a timestamped beacon. Also use a common base between TX timestamp and RX mactime. This eliminates "TX" path delay, which shows up as a constant error in Toffset. Get the global TSF once before iterating over all RX HWs, so they all set a mactime with the same time base. Signed-off-by: Thomas Pedersen --- v2: respin cleanly (Johannes) v3: refactor (Johannes) drivers/net/wireless/mac80211_hwsim.c | 57 ++++++++++++++++++++++----------- 1 file changed, 39 insertions(+), 18 deletions(-) diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c index c918cdb..2bc3945 100644 --- a/drivers/net/wireless/mac80211_hwsim.c +++ b/drivers/net/wireless/mac80211_hwsim.c @@ -363,6 +363,8 @@ struct mac80211_hwsim_data { /* difference between this hw's clock and the real clock, in usecs */ s64 tsf_offset; s64 bcn_delta; + /* absolute beacon transmission time. Used to cover up "tx" delay. */ + u64 abs_bcn_ts; }; @@ -410,15 +412,19 @@ static netdev_tx_t hwsim_mon_xmit(struct sk_buff *skb, return NETDEV_TX_OK; } +static inline u64 mac80211_hwsim_get_tsf_raw(void) +{ + return ktime_to_us(ktime_get_real()); +} + static __le64 __mac80211_hwsim_get_tsf(struct mac80211_hwsim_data *data) { - struct timeval tv = ktime_to_timeval(ktime_get_real()); - u64 now = tv.tv_sec * USEC_PER_SEC + tv.tv_usec; + u64 now = mac80211_hwsim_get_tsf_raw(); return cpu_to_le64(now + data->tsf_offset); } static u64 mac80211_hwsim_get_tsf(struct ieee80211_hw *hw, - struct ieee80211_vif *vif) + struct ieee80211_vif *vif) { struct mac80211_hwsim_data *data = hw->priv; return le64_to_cpu(__mac80211_hwsim_get_tsf(data)); @@ -705,7 +711,7 @@ static bool mac80211_hwsim_tx_frame_no_nl(struct ieee80211_hw *hw, struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); struct ieee80211_rx_status rx_status; - struct ieee80211_rate *txrate = ieee80211_get_tx_rate(hw, info); + u64 now; memset(&rx_status, 0, sizeof(rx_status)); rx_status.flag |= RX_FLAG_MACTIME_START; @@ -731,11 +737,23 @@ static bool mac80211_hwsim_tx_frame_no_nl(struct ieee80211_hw *hw, secpath_reset(skb); nf_reset(skb); + /* + * Get absolute mactime here so all HWs RX at the "same time", and + * absolute TX time for beacon mactime so the timestamp matches. + * Giving beacons a different mactime than non-beacons looks messy, but + * it helps the Toffset be exact and a ~10us mactime discrepancy + * probably doesn't really matter. + */ + if (ieee80211_is_beacon(hdr->frame_control) || + ieee80211_is_probe_resp(hdr->frame_control)) + now = data->abs_bcn_ts; + else + now = mac80211_hwsim_get_tsf_raw(); + /* Copy skb to all enabled radios that are on the current frequency */ spin_lock(&hwsim_radio_lock); list_for_each_entry(data2, &hwsim_radios, list) { struct sk_buff *nskb; - struct ieee80211_mgmt *mgmt; struct tx_iter_data tx_iter_data = { .receive = false, .channel = chan, @@ -787,17 +805,7 @@ static bool mac80211_hwsim_tx_frame_no_nl(struct ieee80211_hw *hw, if (mac80211_hwsim_addr_match(data2, hdr->addr1)) ack = true; - /* set bcn timestamp relative to receiver mactime */ - rx_status.mactime = - le64_to_cpu(__mac80211_hwsim_get_tsf(data2)); - mgmt = (struct ieee80211_mgmt *) nskb->data; - if (ieee80211_is_beacon(mgmt->frame_control) || - ieee80211_is_probe_resp(mgmt->frame_control)) - mgmt->u.beacon.timestamp = cpu_to_le64( - rx_status.mactime + - (data->tsf_offset - data2->tsf_offset) + - 24 * 8 * 10 / txrate->bitrate); - + rx_status.mactime = now + data2->tsf_offset; #if 0 /* * Don't enable this code by default as the OUI 00:00:00 @@ -987,7 +995,11 @@ static void mac80211_hwsim_tx_frame(struct ieee80211_hw *hw, static void mac80211_hwsim_beacon_tx(void *arg, u8 *mac, struct ieee80211_vif *vif) { - struct ieee80211_hw *hw = arg; + struct mac80211_hwsim_data *data = arg; + struct ieee80211_hw *hw = data->hw; + struct ieee80211_tx_info *info; + struct ieee80211_rate *txrate; + struct ieee80211_mgmt *mgmt; struct sk_buff *skb; hwsim_check_magic(vif); @@ -1000,6 +1012,15 @@ static void mac80211_hwsim_beacon_tx(void *arg, u8 *mac, skb = ieee80211_beacon_get(hw, vif); if (skb == NULL) return; + info = IEEE80211_SKB_CB(skb); + txrate = ieee80211_get_tx_rate(hw, info); + + mgmt = (struct ieee80211_mgmt *) skb->data; + /* fake header transmission time */ + data->abs_bcn_ts = mac80211_hwsim_get_tsf_raw(); + mgmt->u.beacon.timestamp = cpu_to_le64(data->abs_bcn_ts + + data->tsf_offset + + 24 * 8 * 10 / txrate->bitrate); mac80211_hwsim_tx_frame(hw, skb, rcu_dereference(vif->chanctx_conf)->def.chan); @@ -1023,7 +1044,7 @@ mac80211_hwsim_beacon(struct hrtimer *timer) ieee80211_iterate_active_interfaces_atomic( hw, IEEE80211_IFACE_ITER_NORMAL, - mac80211_hwsim_beacon_tx, hw); + mac80211_hwsim_beacon_tx, data); /* beacon at new TBTT + beacon interval */ if (data->bcn_delta) { -- 1.7.10.4