mac80211: make rx radiotap header more flexible
authorBruno Randolf <br1@einfach.org>
Thu, 8 May 2008 17:22:43 +0000 (19:22 +0200)
committerJohn W. Linville <linville@tuxdriver.com>
Wed, 14 May 2008 20:29:49 +0000 (16:29 -0400)
use hw flags and rx flags to determine which fields are present in the header
and use all available information from the driver.

make sure radiotap header starts at a naturally aligned address (mod 8) for
all radiotap fields.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
net/mac80211/rx.c

index 474f13662c8428bb83386f8bdda140811c1a66e6..1159a43a3df6921a4f27eb37a87fb2ac74982d0d 100644 (file)
@@ -77,6 +77,134 @@ static inline int should_drop_frame(struct ieee80211_rx_status *status,
        return 0;
 }
 
+static int
+ieee80211_rx_radiotap_len(struct ieee80211_local *local,
+                         struct ieee80211_rx_status *status)
+{
+       int len;
+
+       /* always present fields */
+       len = sizeof(struct ieee80211_radiotap_header) + 9;
+
+       if (status->flag & RX_FLAG_TSFT)
+               len += 8;
+       if (local->hw.flags & IEEE80211_HW_SIGNAL_DB ||
+           local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
+               len += 1;
+       if (local->hw.flags & IEEE80211_HW_NOISE_DBM)
+               len += 1;
+
+       if (len & 1) /* padding for RX_FLAGS if necessary */
+               len++;
+
+       /* make sure radiotap starts at a naturally aligned address */
+       if (len % 8)
+               len = roundup(len, 8);
+
+       return len;
+}
+
+/**
+ * ieee80211_add_rx_radiotap_header - add radiotap header
+ *
+ * add a radiotap header containing all the fields which the hardware provided.
+ */
+static void
+ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
+                                struct sk_buff *skb,
+                                struct ieee80211_rx_status *status,
+                                struct ieee80211_rate *rate,
+                                int rtap_len)
+{
+       struct ieee80211_radiotap_header *rthdr;
+       unsigned char *pos;
+
+       rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
+       memset(rthdr, 0, rtap_len);
+
+       /* radiotap header, set always present flags */
+       rthdr->it_present =
+               cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
+                           (1 << IEEE80211_RADIOTAP_RATE) |
+                           (1 << IEEE80211_RADIOTAP_CHANNEL) |
+                           (1 << IEEE80211_RADIOTAP_ANTENNA) |
+                           (1 << IEEE80211_RADIOTAP_RX_FLAGS));
+       rthdr->it_len = cpu_to_le16(rtap_len);
+
+       pos = (unsigned char *)(rthdr+1);
+
+       /* the order of the following fields is important */
+
+       /* IEEE80211_RADIOTAP_TSFT */
+       if (status->flag & RX_FLAG_TSFT) {
+               *(__le64 *)pos = cpu_to_le64(status->mactime);
+               rthdr->it_present |=
+                       cpu_to_le32(1 << IEEE80211_RADIOTAP_TSFT);
+               pos += 8;
+       }
+
+       /* IEEE80211_RADIOTAP_FLAGS */
+       if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
+               *pos |= IEEE80211_RADIOTAP_F_FCS;
+       pos++;
+
+       /* IEEE80211_RADIOTAP_RATE */
+       *pos = rate->bitrate / 5;
+       pos++;
+
+       /* IEEE80211_RADIOTAP_CHANNEL */
+       *(__le16 *)pos = cpu_to_le16(status->freq);
+       pos += 2;
+       if (status->band == IEEE80211_BAND_5GHZ)
+               *(__le16 *)pos = cpu_to_le16(IEEE80211_CHAN_OFDM |
+                                            IEEE80211_CHAN_5GHZ);
+       else
+               *(__le16 *)pos = cpu_to_le16(IEEE80211_CHAN_DYN |
+                                            IEEE80211_CHAN_2GHZ);
+       pos += 2;
+
+       /* IEEE80211_RADIOTAP_DBM_ANTSIGNAL */
+       if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
+               *pos = status->signal;
+               rthdr->it_present |=
+                       cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
+               pos++;
+       }
+
+       /* IEEE80211_RADIOTAP_DBM_ANTNOISE */
+       if (local->hw.flags & IEEE80211_HW_NOISE_DBM) {
+               *pos = status->noise;
+               rthdr->it_present |=
+                       cpu_to_le32(1 << IEEE80211_RADIOTAP_DBM_ANTNOISE);
+               pos++;
+       }
+
+       /* IEEE80211_RADIOTAP_LOCK_QUALITY is missing */
+
+       /* IEEE80211_RADIOTAP_ANTENNA */
+       *pos = status->antenna;
+       pos++;
+
+       /* IEEE80211_RADIOTAP_DB_ANTSIGNAL */
+       if (local->hw.flags & IEEE80211_HW_SIGNAL_DB) {
+               *pos = status->signal;
+               rthdr->it_present |=
+                       cpu_to_le32(1 << IEEE80211_RADIOTAP_DB_ANTSIGNAL);
+               pos++;
+       }
+
+       /* IEEE80211_RADIOTAP_DB_ANTNOISE is not used */
+
+       /* IEEE80211_RADIOTAP_RX_FLAGS */
+       /* ensure 2 byte alignment for the 2 byte field as required */
+       if ((pos - (unsigned char *)rthdr) & 1)
+               pos++;
+       /* FIXME: when radiotap gets a 'bad PLCP' flag use it here */
+       if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
+               *(__le16 *)pos |= cpu_to_le16(IEEE80211_RADIOTAP_F_RX_BADFCS);
+       pos += 2;
+}
+
 /*
  * This function copies a received frame to all monitor interfaces and
  * returns a cleaned-up SKB that no longer includes the FCS nor the
@@ -89,17 +217,6 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 {
        struct ieee80211_sub_if_data *sdata;
        int needed_headroom = 0;
-       struct ieee80211_radiotap_header *rthdr;
-       __le64 *rttsft = NULL;
-       struct ieee80211_rtap_fixed_data {
-               u8 flags;
-               u8 rate;
-               __le16 chan_freq;
-               __le16 chan_flags;
-               u8 antsignal;
-               u8 padding_for_rxflags;
-               __le16 rx_flags;
-       } __attribute__ ((packed)) *rtfixed;
        struct sk_buff *skb, *skb2;
        struct net_device *prev_dev = NULL;
        int present_fcs_len = 0;
@@ -116,8 +233,8 @@ 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
-               /* room for radiotap header, always present fields and TSFT */
-               needed_headroom = sizeof(*rthdr) + sizeof(*rtfixed) + 8;
+               /* room for the radiotap header based on driver features */
+               needed_headroom = ieee80211_rx_radiotap_len(local, status);
 
        if (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)
                present_fcs_len = FCS_LEN;
@@ -163,55 +280,9 @@ 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));
-               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));
-               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 */
-               rtfixed->rx_flags = 0;
-               if (status->flag &
-                   (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
-                       rtfixed->rx_flags |=
-                               cpu_to_le16(IEEE80211_RADIOTAP_F_RX_BADFCS);
-
-               rtfixed->rate = rate->bitrate / 5;
-
-               rtfixed->chan_freq = cpu_to_le16(status->freq);
-
-               if (status->band == IEEE80211_BAND_5GHZ)
-                       rtfixed->chan_flags =
-                               cpu_to_le16(IEEE80211_CHAN_OFDM |
-                                           IEEE80211_CHAN_5GHZ);
-               else
-                       rtfixed->chan_flags =
-                               cpu_to_le16(IEEE80211_CHAN_DYN |
-                                           IEEE80211_CHAN_2GHZ);
-
-               rtfixed->antsignal = status->signal;
-               rthdr->it_len = cpu_to_le16(rtap_len);
-       }
+       if (!(status->flag & RX_FLAG_RADIOTAP))
+               ieee80211_add_rx_radiotap_header(local, skb, status, rate,
+                                                needed_headroom);
 
        skb_reset_mac_header(skb);
        skb->ip_summed = CHECKSUM_UNNECESSARY;