mac80211: add per-chain signal information to radiotap

When per-chain signal information is available, don't add
the antenna field once but instead add a radiotap namespace
for each chain containing the chain/antenna number and the
signal strength on that chain.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>

1 files changed, 52 insertions, 17 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 23dbcfc69b3b..c9f2ca43856a 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -87,11 +87,13 @@ ieee80211_rx_radiotap_space(struct ieee80211_local *local,
         int len;
 
         /* always present fields */
-        len = sizeof(struct ieee80211_radiotap_header) + 9;
+        len = sizeof(struct ieee80211_radiotap_header) + 8;
 
-        /* allocate extra bitmap */
+        /* allocate extra bitmaps */
         if (status->vendor_radiotap_len)
                 len += 4;
+        if (status->chains)
+                len += 4 * hweight8(status->chains);
 
         if (ieee80211_have_rx_timestamp(status)) {
                 len = ALIGN(len, 8);
@@ -100,6 +102,10 @@ ieee80211_rx_radiotap_space(struct ieee80211_local *local,
         if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM)
                 len += 1;
 
+        /* antenna field, if we don't have per-chain info */
+        if (!status->chains)
+                len += 1;
+
         /* padding for RX_FLAGS if necessary */
         len = ALIGN(len, 2);
 
@@ -116,6 +122,11 @@ ieee80211_rx_radiotap_space(struct ieee80211_local *local,
                 len += 12;
         }
 
+        if (status->chains) {
+                /* antenna and antenna signal fields */
+                len += 2 * hweight8(status->chains);
+        }
+
         if (status->vendor_radiotap_len) {
                 if (WARN_ON_ONCE(status->vendor_radiotap_align == 0))
                         status->vendor_radiotap_align = 1;
@@ -145,8 +156,11 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
         struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
         struct ieee80211_radiotap_header *rthdr;
         unsigned char *pos;
+        __le32 *it_present;
+        u32 it_present_val;
         u16 rx_flags = 0;
-        int mpdulen;
+        int mpdulen, chain;
+        unsigned long chains = status->chains;
 
         mpdulen = skb->len;
         if (!(has_fcs && (local->hw.flags & IEEE80211_HW_RX_INCLUDES_FCS)))
@@ -154,25 +168,39 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 
         rthdr = (struct ieee80211_radiotap_header *)skb_push(skb, rtap_len);
         memset(rthdr, 0, rtap_len);
+        it_present = &rthdr->it_present;
 
         /* radiotap header, set always present flags */
-        rthdr->it_present =
-                cpu_to_le32((1 << IEEE80211_RADIOTAP_FLAGS) |
-                            (1 << IEEE80211_RADIOTAP_CHANNEL) |
-                            (1 << IEEE80211_RADIOTAP_ANTENNA) |
-                            (1 << IEEE80211_RADIOTAP_RX_FLAGS));
         rthdr->it_len = cpu_to_le16(rtap_len + status->vendor_radiotap_len);
+        it_present_val = BIT(IEEE80211_RADIOTAP_FLAGS) |
+                         BIT(IEEE80211_RADIOTAP_CHANNEL) |
+                         BIT(IEEE80211_RADIOTAP_RX_FLAGS);
+
+        if (!status->chains)
+                it_present_val |= BIT(IEEE80211_RADIOTAP_ANTENNA);
 
-        pos = (unsigned char *)(rthdr + 1);
+        for_each_set_bit(chain, &chains, IEEE80211_MAX_CHAINS) {
+                it_present_val |=
+                        BIT(IEEE80211_RADIOTAP_EXT) |
+                        BIT(IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE);
+                put_unaligned_le32(it_present_val, it_present);
+                it_present++;
+                it_present_val = BIT(IEEE80211_RADIOTAP_ANTENNA) |
+                                 BIT(IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
+        }
 
         if (status->vendor_radiotap_len) {
-                rthdr->it_present |=
-                        cpu_to_le32(BIT(IEEE80211_RADIOTAP_VENDOR_NAMESPACE)) |
-                        cpu_to_le32(BIT(IEEE80211_RADIOTAP_EXT));
-                put_unaligned_le32(status->vendor_radiotap_bitmap, pos);
-                pos += 4;
+                it_present_val |= BIT(IEEE80211_RADIOTAP_VENDOR_NAMESPACE) |
+                                  BIT(IEEE80211_RADIOTAP_EXT);
+                put_unaligned_le32(it_present_val, it_present);
+                it_present++;
+                it_present_val = status->vendor_radiotap_bitmap;
         }
 
+        put_unaligned_le32(it_present_val, it_present);
+
+        pos = (void *)(it_present + 1);
+
         /* the order of the following fields is important */
 
         /* IEEE80211_RADIOTAP_TSFT */
@@ -242,9 +270,11 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 
         /* IEEE80211_RADIOTAP_LOCK_QUALITY is missing */
 
-        /* IEEE80211_RADIOTAP_ANTENNA */
-        *pos = status->antenna;
-        pos++;
+        if (!status->chains) {
+                /* IEEE80211_RADIOTAP_ANTENNA */
+                *pos = status->antenna;
+                pos++;
+        }
 
         /* IEEE80211_RADIOTAP_DB_ANTNOISE is not used */
 
@@ -341,6 +371,11 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
                 pos += 2;
         }
 
+        for_each_set_bit(chain, &chains, IEEE80211_MAX_CHAINS) {
+                *pos++ = status->chain_signal[chain];
+                *pos++ = chain;
+        }
+
         if (status->vendor_radiotap_len) {
                 /* ensure 2 byte alignment for the vendor field as required */
                 if ((pos - (u8 *)rthdr) & 1)