nfp: tls: make use of kernel-driven TX resync

When TCP stream gets out of sync (driver stops receiving skbs
with expected TCP sequence numbers) request a TX resync from
the kernel.

We try to distinguish retransmissions from missed transmissions
by comparing the sequence number to expected - if it's further
than the expected one - we probably missed packets.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/crypto/crypto.h

@@ -13,7 +13,6 @@ struct nfp_net_tls_offload_ctx {
 	 */
 
 	u32 next_seq;
-	bool out_of_sync;
 };
 
 #ifdef CONFIG_TLS_DEVICE

drivers/net/ethernet/netronome/nfp/crypto/tls.c

@@ -390,25 +390,30 @@ nfp_net_tls_resync(struct net_device *netdev, struct sock *sk, u32 seq,
 	struct nfp_net_tls_offload_ctx *ntls;
 	struct nfp_crypto_req_update *req;
 	struct sk_buff *skb;
+	gfp_t flags;
 
-	if (WARN_ON_ONCE(direction != TLS_OFFLOAD_CTX_DIR_RX))
-		return;
-
-	skb = nfp_net_tls_alloc_simple(nn, sizeof(*req), GFP_ATOMIC);
+	flags = direction == TLS_OFFLOAD_CTX_DIR_TX ? GFP_KERNEL : GFP_ATOMIC;
+	skb = nfp_net_tls_alloc_simple(nn, sizeof(*req), flags);
 	if (!skb)
 		return;
 
-	ntls = tls_driver_ctx(sk, TLS_OFFLOAD_CTX_DIR_RX);
+	ntls = tls_driver_ctx(sk, direction);
 	req = (void *)skb->data;
 	req->ep_id = 0;
-	req->opcode = NFP_NET_CRYPTO_OP_TLS_1_2_AES_GCM_128_DEC;
+	req->opcode = nfp_tls_1_2_dir_to_opcode(direction);
 	memset(req->resv, 0, sizeof(req->resv));
 	memcpy(req->handle, ntls->fw_handle, sizeof(ntls->fw_handle));
 	req->tcp_seq = cpu_to_be32(seq);
 	memcpy(req->rec_no, rcd_sn, sizeof(req->rec_no));
 
-	nfp_ccm_mbox_post(nn, skb, NFP_CCM_TYPE_CRYPTO_UPDATE,
-			  sizeof(struct nfp_crypto_reply_simple));
+	if (direction == TLS_OFFLOAD_CTX_DIR_TX) {
+		nfp_net_tls_communicate_simple(nn, skb, "sync",
+					       NFP_CCM_TYPE_CRYPTO_UPDATE);
+		ntls->next_seq = seq;
+	} else {
+		nfp_ccm_mbox_post(nn, skb, NFP_CCM_TYPE_CRYPTO_UPDATE,
+				  sizeof(struct nfp_crypto_reply_simple));
+	}
 }
 
 static const struct tlsdev_ops nfp_net_tls_ops = {

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

@@ -829,6 +829,7 @@ nfp_net_tls_tx(struct nfp_net_dp *dp, struct nfp_net_r_vector *r_vec,
 {
 	struct nfp_net_tls_offload_ctx *ntls;
 	struct sk_buff *nskb;
+	bool resync_pending;
 	u32 datalen, seq;
 
 	if (likely(!dp->ktls_tx))
@@ -839,7 +840,8 @@ nfp_net_tls_tx(struct nfp_net_dp *dp, struct nfp_net_r_vector *r_vec,
 	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 (unlikely(ntls->next_seq != seq || ntls->out_of_sync)) {
+	resync_pending = tls_offload_tx_resync_pending(skb->sk);
+	if (unlikely(resync_pending || ntls->next_seq != seq)) {
 		/* Pure ACK out of order already */
 		if (!datalen)
 			return skb;
@@ -869,8 +871,8 @@ nfp_net_tls_tx(struct nfp_net_dp *dp, struct nfp_net_r_vector *r_vec,
 		}
 
 		/* jump forward, a TX may have gotten lost, need to sync TX */
-		if (!ntls->out_of_sync && seq - ntls->next_seq < U32_MAX / 4)
-			ntls->out_of_sync = true;
+		if (!resync_pending && seq - ntls->next_seq < U32_MAX / 4)
+			tls_offload_tx_resync_request(nskb->sk);
 
 		*nr_frags = 0;
 		return nskb;