wifi: mac80211_hwsim: move timestamp writing later in the datapath

By delegating writing the timestamp into beacons and probe responses, we
can remove the abs_bcn_ts from the global data and still avoid any time
offset issues. This also seems conceptually closer to "real" hardware
where the timestamp will be written late in the TX path.

Move sending the SKB to the monitor interface to happen later, so that
the frame timestamp has the value filled in by mac80211_hwsim.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20260504101829.ad4d77d85e0d.I86810bbbf9b171acc6dbf07f9904ce1686b5167a@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/virtual/mac80211_hwsim_i.h b/drivers/net/wireless/virtual/mac80211_hwsim_i.h
index 741eb08f8a85134e2d053a5457fdc3ed421d95c5..b4d0a3869619e6c72604d4623847666858570eab 100644 (file)
--- a/drivers/net/wireless/virtual/mac80211_hwsim_i.h
+++ b/drivers/net/wireless/virtual/mac80211_hwsim_i.h
@@ -104,8 +104,6 @@ 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;
 
        /* Stats */
        u64 tx_pkts;

diff --git a/drivers/net/wireless/virtual/mac80211_hwsim_main.c b/drivers/net/wireless/virtual/mac80211_hwsim_main.c
index 3bda5532ab62f844c04b2e2502d206428f5f394b..5bf6541498ec75161b28a73e8c1f377f95c99193 100644 (file)
--- a/drivers/net/wireless/virtual/mac80211_hwsim_main.c
+++ b/drivers/net/wireless/virtual/mac80211_hwsim_main.c
@@ -1523,6 +1523,43 @@ static inline u16 trans_tx_rate_flags_ieee2hwsim(struct ieee80211_tx_rate *rate)
        return result;
 }
 
+static void mac80211_hwsim_write_tsf(struct mac80211_hwsim_data *data,
+                                    struct sk_buff *skb, u64 sim_time)
+{
+       struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+       struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+       struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *)skb->data;
+       struct ieee80211_rate *txrate;
+       /* TODO: get MCS */
+       int bitrate = 100;
+
+       txrate = ieee80211_get_tx_rate(data->hw, info);
+       if (txrate)
+               bitrate = txrate->bitrate;
+
+       if (skb->len >= offsetofend(typeof(*mgmt), u.probe_resp.timestamp) &&
+           ieee80211_is_probe_resp(hdr->frame_control)) {
+               mgmt->u.probe_resp.timestamp =
+                       cpu_to_le64(sim_time + data->tsf_offset +
+                                   24 * 8 * 10 / bitrate);
+       } else if (skb->len >= offsetofend(typeof(*mgmt), u.beacon.timestamp) &&
+                  ieee80211_is_beacon(mgmt->frame_control)) {
+               mgmt->u.beacon.timestamp = cpu_to_le64(sim_time +
+                                                      data->tsf_offset +
+                                                      24 * 8 * 10 /
+                                                      bitrate);
+       } else if (skb->len >= offsetofend(struct ieee80211_ext,
+                                          u.s1g_beacon.timestamp) &&
+                  ieee80211_is_s1g_beacon(mgmt->frame_control)) {
+               struct ieee80211_ext *ext = (void *)mgmt;
+
+               ext->u.s1g_beacon.timestamp = cpu_to_le32(sim_time +
+                                                         data->tsf_offset +
+                                                         10 * 8 * 10 /
+                                                         bitrate);
+       }
+}
+
 static void mac80211_hwsim_tx_frame_nl(struct ieee80211_hw *hw,
                                       struct sk_buff *my_skb,
                                       int dst_portid,
@@ -1538,6 +1575,7 @@ static void mac80211_hwsim_tx_frame_nl(struct ieee80211_hw *hw,
        struct hwsim_tx_rate tx_attempts[IEEE80211_TX_MAX_RATES];
        struct hwsim_tx_rate_flag tx_attempts_flags[IEEE80211_TX_MAX_RATES];
        uintptr_t cookie;
+       u64 sim_tsf;
 
        if (data->ps != PS_DISABLED)
                hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PM);
@@ -1550,6 +1588,9 @@ static void mac80211_hwsim_tx_frame_nl(struct ieee80211_hw *hw,
                }
        }
 
+       sim_tsf = mac80211_hwsim_get_sim_tsf();
+       mac80211_hwsim_write_tsf(data, my_skb, sim_tsf);
+
        skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_ATOMIC);
        if (skb == NULL)
                goto nla_put_failure;
@@ -1781,7 +1822,11 @@ 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;
-       u64 sim_tsf;
+       u64 sim_tsf = mac80211_hwsim_get_sim_tsf();
+
+       mac80211_hwsim_write_tsf(data, skb, sim_tsf);
+
+       mac80211_hwsim_monitor_rx(hw, skb, chan);
 
        memset(&rx_status, 0, sizeof(rx_status));
        rx_status.flag |= RX_FLAG_MACTIME_START;
@@ -1824,20 +1869,9 @@ static bool mac80211_hwsim_tx_frame_no_nl(struct ieee80211_hw *hw,
        skb_ext_reset(skb);
        nf_reset_ct(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)) {
+           ieee80211_is_probe_resp(hdr->frame_control))
                rx_status.boottime_ns = ktime_get_boottime_ns();
-               sim_tsf = data->abs_bcn_ts;
-       } else {
-               sim_tsf = mac80211_hwsim_get_sim_tsf();
-       }
 
        /* Copy skb to all enabled radios that are on the current frequency */
        spin_lock(&hwsim_radio_lock);
@@ -2137,27 +2171,6 @@ static void mac80211_hwsim_tx(struct ieee80211_hw *hw,
                        return;
        }
 
-       if (skb->len >= 24 + 8 &&
-           ieee80211_is_probe_resp(hdr->frame_control)) {
-               /* fake header transmission time */
-               struct ieee80211_mgmt *mgmt;
-               struct ieee80211_rate *txrate;
-               /* TODO: get MCS */
-               int bitrate = 100;
-               u64 ts;
-
-               mgmt = (struct ieee80211_mgmt *)skb->data;
-               txrate = ieee80211_get_tx_rate(hw, txi);
-               if (txrate)
-                       bitrate = txrate->bitrate;
-               ts = mac80211_hwsim_get_sim_tsf();
-               mgmt->u.probe_resp.timestamp =
-                       cpu_to_le64(ts + data->tsf_offset +
-                                   24 * 8 * 10 / bitrate);
-       }
-
-       mac80211_hwsim_monitor_rx(hw, skb, channel);
-
        /* wmediumd mode check */
        _portid = READ_ONCE(data->wmediumd);
 
@@ -2291,8 +2304,6 @@ static void mac80211_hwsim_tx_frame(struct ieee80211_hw *hw,
                                       ARRAY_SIZE(txi->control.rates));
        }
 
-       mac80211_hwsim_monitor_rx(hw, skb, chan);
-
        if (_portid || hwsim_virtio_enabled)
                return mac80211_hwsim_tx_frame_nl(hw, skb, _portid, chan);
 
@@ -2310,10 +2321,6 @@ static void __mac80211_hwsim_beacon_tx(struct ieee80211_bss_conf *link_conf,
 {
        struct hwsim_vif_priv *vp = (void *)vif->drv_priv;
        struct ieee80211_tx_info *info;
-       struct ieee80211_rate *txrate;
-       struct ieee80211_mgmt *mgmt;
-       /* TODO: get MCS */
-       int bitrate = 100;
 
        if (vp->skip_beacons[link_conf->link_id]) {
                vp->skip_beacons[link_conf->link_id]--;
@@ -2327,27 +2334,6 @@ static void __mac80211_hwsim_beacon_tx(struct ieee80211_bss_conf *link_conf,
                                       info->control.rates,
                                       ARRAY_SIZE(info->control.rates));
 
-       txrate = ieee80211_get_tx_rate(hw, info);
-       if (txrate)
-               bitrate = txrate->bitrate;
-
-       mgmt = (struct ieee80211_mgmt *) skb->data;
-       /* fake header transmission time */
-       data->abs_bcn_ts = mac80211_hwsim_get_sim_tsf();
-       if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
-               struct ieee80211_ext *ext = (void *) mgmt;
-
-               ext->u.s1g_beacon.timestamp = cpu_to_le32(data->abs_bcn_ts +
-                                                         data->tsf_offset +
-                                                         10 * 8 * 10 /
-                                                         bitrate);
-       } else {
-               mgmt->u.beacon.timestamp = cpu_to_le64(data->abs_bcn_ts +
-                                                      data->tsf_offset +
-                                                      24 * 8 * 10 /
-                                                      bitrate);
-       }
-
        mac80211_hwsim_tx_frame(hw, skb,
                        rcu_dereference(link_conf->chanctx_conf)->def.chan);
 }
@@ -6033,6 +6019,8 @@ static int hwsim_tx_info_frame_received_nl(struct sk_buff *skb_2,
        if (!found)
                goto out;
 
+       mac80211_hwsim_monitor_rx(data2->hw, skb, data2->channel);
+
        /* Tx info received because the frame was broadcasted on user space,
         so we get all the necessary info: tx attempts and skb control buff */