net/macsec: Add MACsec skb_metadata_dst Rx Data path support

Like in the Tx changes, if there are more than one MACsec device with
the same MAC address as in the packet's destination MAC, the packet will
be forward only to this device and not neccessarly to the desired one.

Offloading device drivers will mark offloaded MACsec SKBs with the
corresponding SCI in the skb_metadata_dst so the macsec rx handler will
know to which port to divert those skbs, instead of wrongly solely
relaying on dst MAC address comparison.
Signed-off-by: Lior Nahmanson <liorna@nvidia.com>
Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macsec.c

@@ -1025,11 +1025,13 @@ static enum rx_handler_result handle_not_macsec(struct sk_buff *skb)
 	/* Deliver to the uncontrolled port by default */
 	enum rx_handler_result ret = RX_HANDLER_PASS;
 	struct ethhdr *hdr = eth_hdr(skb);
+	struct metadata_dst *md_dst;
 	struct macsec_rxh_data *rxd;
 	struct macsec_dev *macsec;
 
 	rcu_read_lock();
 	rxd = macsec_data_rcu(skb->dev);
+	md_dst = skb_metadata_dst(skb);
 
 	list_for_each_entry_rcu(macsec, &rxd->secys, secys) {
 		struct sk_buff *nskb;
@@ -1040,6 +1042,10 @@ static enum rx_handler_result handle_not_macsec(struct sk_buff *skb)
 		 * the SecTAG, so we have to deduce which port to deliver to.
 		 */
 		if (macsec_is_offloaded(macsec) && netif_running(ndev)) {
+			if (md_dst && md_dst->type == METADATA_MACSEC &&
+			    (!find_rx_sc(&macsec->secy, md_dst->u.macsec_info.sci)))
+				continue;
+
 			if (ether_addr_equal_64bits(hdr->h_dest,
 						    ndev->dev_addr)) {
 				/* exact match, divert skb to this port */