wifi: mac80211: add support for driver adding radiotap TLVs

The new TLV format enables adding TLVs after the fixed
fields in radiotap, as part of the radiotap header.
Support this and move vendor data to the TLV format,
allowing a reuse of the RX_FLAG_RADIOTAP_VENDOR_DATA as
the new RX_FLAG_RADIOTAP_TLV_AT_END flag.

Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230301115906.b18fd5da8477.I576400ec40a7b35ef97a3b09a99b3a49e9174786@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 27 insertions, 55 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index f63ed6b91d9b..0255c5745e1c 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -55,7 +55,7 @@ static struct sk_buff *ieee80211_clean_skb(struct sk_buff *skb,
 	/* After pulling radiotap header, clear all flags that indicate
 	 * info in skb->data.
 	 */
-	status->flag &= ~(RX_FLAG_RADIOTAP_VENDOR_DATA |
+	status->flag &= ~(RX_FLAG_RADIOTAP_TLV_AT_END |
 			  RX_FLAG_RADIOTAP_LSIG |
 			  RX_FLAG_RADIOTAP_HE_MU |
 			  RX_FLAG_RADIOTAP_HE);
@@ -126,9 +126,6 @@ ieee80211_rx_radiotap_hdrlen(struct ieee80211_local *local,
 	/* allocate extra bitmaps */
 	if (status->chains)
 		len += 4 * hweight8(status->chains);
-	/* vendor presence bitmap */
-	if (status->flag & RX_FLAG_RADIOTAP_VENDOR_DATA)
-		len += 4;
 
 	if (ieee80211_have_rx_timestamp(status)) {
 		len = ALIGN(len, 8);
@@ -190,34 +187,28 @@ ieee80211_rx_radiotap_hdrlen(struct ieee80211_local *local,
 		len += 2 * hweight8(status->chains);
 	}
 
-	if (status->flag & RX_FLAG_RADIOTAP_VENDOR_DATA) {
-		struct ieee80211_vendor_radiotap *rtap;
-		int vendor_data_offset = 0;
+	if (status->flag & RX_FLAG_RADIOTAP_TLV_AT_END) {
+		int tlv_offset = 0;
 
 		/*
 		 * The position to look at depends on the existence (or non-
 		 * existence) of other elements, so take that into account...
 		 */
 		if (status->flag & RX_FLAG_RADIOTAP_HE)
-			vendor_data_offset +=
+			tlv_offset +=
 				sizeof(struct ieee80211_radiotap_he);
 		if (status->flag & RX_FLAG_RADIOTAP_HE_MU)
-			vendor_data_offset +=
+			tlv_offset +=
 				sizeof(struct ieee80211_radiotap_he_mu);
 		if (status->flag & RX_FLAG_RADIOTAP_LSIG)
-			vendor_data_offset +=
+			tlv_offset +=
 				sizeof(struct ieee80211_radiotap_lsig);
 
-		rtap = (void *)&skb->data[vendor_data_offset];
+		/* ensure 4 byte alignment for TLV */
+		len = ALIGN(len, 4);
 
-		/* alignment for fixed 6-byte vendor data header */
-		len = ALIGN(len, 2);
-		/* vendor data header */
-		len += 6;
-		if (WARN_ON(rtap->align == 0))
-			rtap->align = 1;
-		len = ALIGN(len, rtap->align);
-		len += rtap->len + rtap->pad;
+		/* TLVs until the mac header */
+		len += skb_mac_header(skb) - &skb->data[tlv_offset];
 	}
 
 	return len;
@@ -313,9 +304,9 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 	u32 it_present_val;
 	u16 rx_flags = 0;
 	u16 channel_flags = 0;
+	u32 tlvs_len = 0;
 	int mpdulen, chain;
 	unsigned long chains = status->chains;
-	struct ieee80211_vendor_radiotap rtap = {};
 	struct ieee80211_radiotap_he he = {};
 	struct ieee80211_radiotap_he_mu he_mu = {};
 	struct ieee80211_radiotap_lsig lsig = {};
@@ -336,18 +327,17 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 		skb_pull(skb, sizeof(lsig));
 	}
 
-	if (status->flag & RX_FLAG_RADIOTAP_VENDOR_DATA) {
-		rtap = *(struct ieee80211_vendor_radiotap *)skb->data;
-		/* rtap.len and rtap.pad are undone immediately */
-		skb_pull(skb, sizeof(rtap) + rtap.len + rtap.pad);
+	if (status->flag & RX_FLAG_RADIOTAP_TLV_AT_END) {
+		/* data is pointer at tlv all other info was pulled off */
+		tlvs_len = skb_mac_header(skb) - skb->data;
 	}
 
 	mpdulen = skb->len;
 	if (!(has_fcs && ieee80211_hw_check(&local->hw, RX_INCLUDES_FCS)))
 		mpdulen += FCS_LEN;
 
-	rthdr = skb_push(skb, rtap_len);
-	memset(rthdr, 0, rtap_len - rtap.len - rtap.pad);
+	rthdr = skb_push(skb, rtap_len - tlvs_len);
+	memset(rthdr, 0, rtap_len - tlvs_len);
 	it_present = &rthdr->it_present;
 
 	/* radiotap header, set always present flags */
@@ -369,13 +359,8 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 				 BIT(IEEE80211_RADIOTAP_DBM_ANTSIGNAL);
 	}
 
-	if (status->flag & RX_FLAG_RADIOTAP_VENDOR_DATA) {
-		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 = rtap.present;
-	}
+	if (status->flag & RX_FLAG_RADIOTAP_TLV_AT_END)
+		it_present_val |= BIT(IEEE80211_RADIOTAP_TLV);
 
 	put_unaligned_le32(it_present_val, it_present);
 
@@ -706,22 +691,6 @@ ieee80211_add_rx_radiotap_header(struct ieee80211_local *local,
 		*pos++ = status->chain_signal[chain];
 		*pos++ = chain;
 	}
-
-	if (status->flag & RX_FLAG_RADIOTAP_VENDOR_DATA) {
-		/* ensure 2 byte alignment for the vendor field as required */
-		if ((pos - (u8 *)rthdr) & 1)
-			*pos++ = 0;
-		*pos++ = rtap.oui[0];
-		*pos++ = rtap.oui[1];
-		*pos++ = rtap.oui[2];
-		*pos++ = rtap.subns;
-		put_unaligned_le16(rtap.len, pos);
-		pos += 2;
-		/* align the actual payload as requested */
-		while ((pos - (u8 *)rthdr) & (rtap.align - 1))
-			*pos++ = 0;
-		/* data (and possible padding) already follows */
-	}
 }
 
 static struct sk_buff *
@@ -797,6 +766,13 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 	bool only_monitor = false;
 	unsigned int min_head_len;
 
+	if (WARN_ON_ONCE(status->flag & RX_FLAG_RADIOTAP_TLV_AT_END &&
+			 !skb_mac_header_was_set(origskb))) {
+		/* with this skb no way to know where frame payload starts */
+		dev_kfree_skb(origskb);
+		return NULL;
+	}
+
 	if (status->flag & RX_FLAG_RADIOTAP_HE)
 		rtap_space += sizeof(struct ieee80211_radiotap_he);
 
@@ -806,12 +782,8 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 	if (status->flag & RX_FLAG_RADIOTAP_LSIG)
 		rtap_space += sizeof(struct ieee80211_radiotap_lsig);
 
-	if (unlikely(status->flag & RX_FLAG_RADIOTAP_VENDOR_DATA)) {
-		struct ieee80211_vendor_radiotap *rtap =
-			(void *)(origskb->data + rtap_space);
-
-		rtap_space += sizeof(*rtap) + rtap->len + rtap->pad;
-	}
+	if (status->flag & RX_FLAG_RADIOTAP_TLV_AT_END)
+		rtap_space += skb_mac_header(origskb) - &origskb->data[rtap_space];
 
 	min_head_len = rtap_space;