nfp: tls: undo TLS sequence tracking when dropping the frame

If driver has to drop the TLS frame it needs to undo the TCP
sequence tracking changes, otherwise device will receive
segments out of order and drop them.
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NDirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -893,6 +893,28 @@ nfp_net_tls_tx(struct nfp_net_dp *dp, struct nfp_net_r_vector *r_vec,
 	return skb;
 }
 
+static void nfp_net_tls_tx_undo(struct sk_buff *skb, u64 tls_handle)
+{
+#ifdef CONFIG_TLS_DEVICE
+	struct nfp_net_tls_offload_ctx *ntls;
+	u32 datalen, seq;
+
+	if (!tls_handle)
+		return;
+	if (WARN_ON_ONCE(!skb->sk || !tls_is_sk_tx_device_offloaded(skb->sk)))
+		return;
+
+	datalen = skb->len - (skb_transport_offset(skb) + tcp_hdrlen(skb));
+	seq = ntohl(tcp_hdr(skb)->seq);
+
+	ntls = tls_driver_ctx(skb->sk, TLS_OFFLOAD_CTX_DIR_TX);
+	if (ntls->next_seq == seq + datalen)
+		ntls->next_seq = seq;
+	else
+		WARN_ON_ONCE(1);
+#endif
+}
+
 static void nfp_net_tx_xmit_more_flush(struct nfp_net_tx_ring *tx_ring)
 {
 	wmb();
@@ -1102,6 +1124,7 @@ static int nfp_net_tx(struct sk_buff *skb, struct net_device *netdev)
 	u64_stats_update_begin(&r_vec->tx_sync);
 	r_vec->tx_errors++;
 	u64_stats_update_end(&r_vec->tx_sync);
+	nfp_net_tls_tx_undo(skb, tls_handle);
 	dev_kfree_skb_any(skb);
 	return NETDEV_TX_OK;
 }