net/tls: Add force_resync for driver resync

This patch adds a field to the tls rx offload context which enables
drivers to force a send_resync call.

This field can be used by drivers to request a resync at the next
possible tls record. It is beneficial for hardware that provides the
resync sequence number asynchronously. In such cases, the packet that
triggered the resync does not contain the information required for a
resync. Instead, the driver requests resync for all the following
TLS record until the asynchronous notification with the resync request
TCP sequence arrives.

A following series for mlx5e ConnectX-6DX TLS RX offload support will
use this mechanism.

Signed-off-by: Boris Pismenny <[e-mail]>
Signed-off-by: Tariq Toukan <[e-mail]>
Reviewed-by: Maxim Mikityanskiy <[e-mail]>
Reviewed-by: Saeed Mahameed <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/tls.h

···
 #endif
 
 /* The TLS context is valid until sk_destruct is called */
+#define RESYNC_REQ (1 << 0)
+#define RESYNC_REQ_FORCE (1 << 1)
 static inline void tls_offload_rx_resync_request(struct sock *sk, __be32 seq)
 {
 	struct tls_context *tls_ctx = tls_get_ctx(sk);
 	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
 
-	atomic64_set(&rx_ctx->resync_req, ((u64)ntohl(seq) << 32) | 1);
+	atomic64_set(&rx_ctx->resync_req, ((u64)ntohl(seq) << 32) | RESYNC_REQ);
+}
+
+static inline void tls_offload_rx_force_resync_request(struct sock *sk)
+{
+	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
+
+	atomic64_set(&rx_ctx->resync_req, RESYNC_REQ | RESYNC_REQ_FORCE);
 }
 
 static inline void

net/tls/tls_device.c

···
 {
 	struct tls_context *tls_ctx = tls_get_ctx(sk);
 	struct tls_offload_context_rx *rx_ctx;
+	bool is_req_pending, is_force_resync;
 	u8 rcd_sn[TLS_MAX_REC_SEQ_SIZE];
-	u32 sock_data, is_req_pending;
 	struct tls_prot_info *prot;
 	s64 resync_req;
+	u32 sock_data;
 	u32 req_seq;
 
 	if (tls_ctx->rx_conf != TLS_HW)
···
 		resync_req = atomic64_read(&rx_ctx->resync_req);
 		req_seq = resync_req >> 32;
 		seq += TLS_HEADER_SIZE - 1;
-		is_req_pending = resync_req;
+		is_req_pending = resync_req & RESYNC_REQ;
+		is_force_resync = resync_req & RESYNC_REQ_FORCE;
 
-		if (likely(!is_req_pending) || req_seq != seq ||
+		if (likely(!is_req_pending) ||
+		    (!is_force_resync && req_seq != seq) ||
 		    !atomic64_try_cmpxchg(&rx_ctx->resync_req, &resync_req, 0))
 			return;
 		break;