mac80211: conditionally include timestamp in radiotap information

This makes mac80211 include the low-level MAC timestamp
in the radiotap header if the driver indicated (by a new
RX flag) that the timestamp is valid.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 0d67b331ee7252cd140ff65ecab2e64e65aa95ed..3bd970f29f29d1fbe81a73d4dcf7bdc4cbb8fff0 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -350,6 +350,8 @@ struct ieee80211_tx_control {
  *     the frame.
  * @RX_FLAG_FAILED_PLCP_CRC: Set this flag if the PCLP check failed on
  *     the frame.
+ * @RX_FLAG_TSFT: The timestamp passed in the RX status (@mactime field)
+ *     is valid.
  */
 enum mac80211_rx_flags {
        RX_FLAG_MMIC_ERROR      = 1<<0,
@@ -359,6 +361,7 @@ enum mac80211_rx_flags {
        RX_FLAG_IV_STRIPPED     = 1<<4,
        RX_FLAG_FAILED_FCS_CRC  = 1<<5,
        RX_FLAG_FAILED_PLCP_CRC = 1<<6,
+       RX_FLAG_TSFT            = 1<<7,
 };
 
 /**

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index c542fc1c983d25564ef27fad45a1c0a39fed8435..9cd59ecbcd674ddefd4cf6c3da13d3651bd6cfa6 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -79,8 +79,9 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
        struct ieee80211_sub_if_data *sdata;
        struct ieee80211_rate *rate;
        int needed_headroom = 0;
-       struct ieee80211_rtap_hdr {
-               struct ieee80211_radiotap_header hdr;
+       struct ieee80211_radiotap_header *rthdr;
+       __le64 *rttsft = NULL;
+       struct ieee80211_rtap_fixed_data {
                u8 flags;
                u8 rate;
                __le16 chan_freq;
@@ -88,7 +89,7 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
                u8 antsignal;
                u8 padding_for_rxflags;
                __le16 rx_flags;
-       } __attribute__ ((packed)) *rthdr;
+       } __attribute__ ((packed)) *rtfixed;
        struct sk_buff *skb, *skb2;
        struct net_device *prev_dev = NULL;
        int present_fcs_len = 0;
@@ -105,7 +106,8 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
        if (status->flag & RX_FLAG_RADIOTAP)
                rtap_len = ieee80211_get_radiotap_len(origskb->data);
        else
-               needed_headroom = sizeof(*rthdr);
+               /* room for radiotap header, always present fields and TSFT */
+               needed_headroom = sizeof(*rthdr) + sizeof(*rtfixed) + 8;
 
        if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
                present_fcs_len = FCS_LEN;
@@ -133,7 +135,7 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
                 * them allocate enough headroom to start with.
                 */
                if (skb_headroom(skb) < needed_headroom &&
-                   pskb_expand_head(skb, sizeof(*rthdr), 0, GFP_ATOMIC)) {
+                   pskb_expand_head(skb, needed_headroom, 0, GFP_ATOMIC)) {
                        dev_kfree_skb(skb);
                        return NULL;
                }
@@ -152,42 +154,56 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 
        /* if necessary, prepend radiotap information */
        if (!(status->flag & RX_FLAG_RADIOTAP)) {
+               rtfixed = (void *) skb_push(skb, sizeof(*rtfixed));
+               rtap_len = sizeof(*rthdr) + sizeof(*rtfixed);
+               if (status->flag & RX_FLAG_TSFT) {
+                       rttsft = (void *) skb_push(skb, sizeof(*rttsft));
+                       rtap_len += 8;
+               }
                rthdr = (void *) skb_push(skb, sizeof(*rthdr));
                memset(rthdr, 0, sizeof(*rthdr));
-               rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
-               rthdr->hdr.it_present =
+               memset(rtfixed, 0, sizeof(*rtfixed));
+               rthdr->it_present =
                        cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
                                    (1 << IEEE80211_RADIOTAP_RATE) |
                                    (1 << IEEE80211_RADIOTAP_CHANNEL) |
                                    (1 << IEEE80211_RADIOTAP_DB_ANTSIGNAL) |
                                    (1 << IEEE80211_RADIOTAP_RX_FLAGS));
-               rthdr->flags = local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS ?
-                              IEEE80211_RADIOTAP_F_FCS : 0;
+               rtfixed->flags = 0;
+               if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
+                       rtfixed->flags |= IEEE80211_RADIOTAP_F_FCS;
+
+               if (rttsft) {
+                       *rttsft = cpu_to_le64(status->mactime);
+                       rthdr->it_present |=
+                               cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
+               }
 
                /* FIXME: when radiotap gets a 'bad PLCP' flag use it here */
-               rthdr->rx_flags = 0;
+               rtfixed->rx_flags = 0;
                if (status->flag &
                    (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
-                       rthdr->rx_flags |=
+                       rtfixed->rx_flags |=
                                cpu_to_le16(IEEE80211_RADIOTAP_F_RX_BADFCS);
 
                rate = ieee80211_get_rate(local, status->phymode,
                                          status->rate);
                if (rate)
-                       rthdr->rate = rate->rate / 5;
+                       rtfixed->rate = rate->rate / 5;
 
-               rthdr->chan_freq = cpu_to_le16(status->freq);
+               rtfixed->chan_freq = cpu_to_le16(status->freq);
 
                if (status->phymode == MODE_IEEE80211A)
-                       rthdr->chan_flags =
+                       rtfixed->chan_flags =
                                cpu_to_le16(IEEE80211_CHAN_OFDM |
                                            IEEE80211_CHAN_5GHZ);
                else
-                       rthdr->chan_flags =
+                       rtfixed->chan_flags =
                                cpu_to_le16(IEEE80211_CHAN_DYN |
                                            IEEE80211_CHAN_2GHZ);
 
-               rthdr->antsignal = status->ssi;
+               rtfixed->antsignal = status->ssi;
+               rthdr->it_len = cpu_to_le16(rtap_len);
        }
 
        skb_set_mac_header(skb, 0);