mac80211: support A-MPDU status reporting

Support getting A-MPDU status information from the
drivers and reporting it to userspace via radiotap
in the standard fields.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 0cb4ede..78bf6c7 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -60,7 +60,9 @@
 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 
-	if (status->flag & (RX_FLAG_FAILED_FCS_CRC | RX_FLAG_FAILED_PLCP_CRC))
+	if (status->flag & (RX_FLAG_FAILED_FCS_CRC |
+			    RX_FLAG_FAILED_PLCP_CRC |
+			    RX_FLAG_AMPDU_IS_ZEROLEN))
 		return 1;
 	if (unlikely(skb->len < 16 + present_fcs_len))
 		return 1;
@@ -91,6 +93,13 @@
 	if (status->flag & RX_FLAG_HT) /* HT info */
 		len += 3;
 
+	if (status->flag & RX_FLAG_AMPDU_DETAILS) {
+		/* padding */
+		while (len & 3)
+			len++;
+		len += 8;
+	}
+
 	return len;
 }
 
@@ -215,6 +224,37 @@
 		pos++;
 		*pos++ = status->rate_idx;
 	}
+
+	if (status->flag & RX_FLAG_AMPDU_DETAILS) {
+		u16 flags = 0;
+
+		/* ensure 4 byte alignment */
+		while ((pos - (u8 *)rthdr) & 3)
+			pos++;
+		rthdr->it_present |=
+			cpu_to_le32(1 << IEEE80211_RADIOTAP_AMPDU_STATUS);
+		put_unaligned_le32(status->ampdu_reference, pos);
+		pos += 4;
+		if (status->flag & RX_FLAG_AMPDU_REPORT_ZEROLEN)
+			flags |= IEEE80211_RADIOTAP_AMPDU_REPORT_ZEROLEN;
+		if (status->flag & RX_FLAG_AMPDU_IS_ZEROLEN)
+			flags |= IEEE80211_RADIOTAP_AMPDU_IS_ZEROLEN;
+		if (status->flag & RX_FLAG_AMPDU_LAST_KNOWN)
+			flags |= IEEE80211_RADIOTAP_AMPDU_LAST_KNOWN;
+		if (status->flag & RX_FLAG_AMPDU_IS_LAST)
+			flags |= IEEE80211_RADIOTAP_AMPDU_IS_LAST;
+		if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_ERROR)
+			flags |= IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_ERR;
+		if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_KNOWN)
+			flags |= IEEE80211_RADIOTAP_AMPDU_DELIM_CRC_KNOWN;
+		put_unaligned_le16(flags, pos);
+		pos += 2;
+		if (status->flag & RX_FLAG_AMPDU_DELIM_CRC_KNOWN)
+			*pos++ = status->ampdu_delimiter_crc;
+		else
+			*pos++ = 0;
+		*pos++ = 0;
+	}
 }
 
 /*