[tls] Group transmit and receive state in TLS connection structure

The TLS connection structure has grown to become unmanageably large as
new features and support for new TLS protocol versions have been added
over time.

Split out the portions of struct tls_connection that are specific to
transmit and receive operations into separate structures, and simplify
some structure field names.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/tls.h

@@ -250,6 +250,14 @@ struct tls_cipherspec {
 	void *fixed_iv;
 };
 
+/** A TLS cipher specification pair */
+struct tls_cipherspec_pair {
+	/** Current cipher specification */
+	struct tls_cipherspec active;
+	/** Next cipher specification */
+	struct tls_cipherspec pending;
+};
+
 /** A TLS signature and hash algorithm identifier */
 struct tls_signature_hash_id {
 	/** Hash algorithm */
@@ -340,6 +348,36 @@ struct tls_session {
 	struct list_head conn;
 };
 
+/** TLS transmit state */
+struct tls_tx {
+	/** Cipher specifications */
+	struct tls_cipherspec_pair cipherspec;
+	/** Sequence number */
+	uint64_t seq;
+	/** Pending transmissions */
+	unsigned int pending;
+	/** Transmit process */
+	struct process process;
+};
+
+/** TLS receive state */
+struct tls_rx {
+	/** Cipher specifications */
+	struct tls_cipherspec_pair cipherspec;
+	/** Sequence number */
+	uint64_t seq;
+	/** State machine current state */
+	enum tls_rx_state state;
+	/** Current received record header */
+	struct tls_header header;
+	/** Current received record header (static I/O buffer) */
+	struct io_buffer iobuf;
+	/** List of received data buffers */
+	struct list_head data;
+	/** Received handshake fragment */
+	struct io_buffer *handshake;
+};
+
 /** A TLS connection */
 struct tls_connection {
 	/** Reference counter */
@@ -365,14 +403,6 @@ struct tls_connection {
 
 	/** Protocol version */
 	uint16_t version;
-	/** Current TX cipher specification */
-	struct tls_cipherspec tx_cipherspec;
-	/** Next TX cipher specification */
-	struct tls_cipherspec tx_cipherspec_pending;
-	/** Current RX cipher specification */
-	struct tls_cipherspec rx_cipherspec;
-	/** Next RX cipher specification */
-	struct tls_cipherspec rx_cipherspec_pending;
 	/** Master secret */
 	uint8_t master_secret[48];
 	/** Server random bytes */
@@ -410,25 +440,10 @@ struct tls_connection {
 	/** Certificate validation pending operation */
 	struct pending_operation validation;
 
-	/** TX sequence number */
-	uint64_t tx_seq;
-	/** TX pending transmissions */
-	unsigned int tx_pending;
-	/** TX process */
-	struct process process;
-
-	/** RX sequence number */
-	uint64_t rx_seq;
-	/** RX state */
-	enum tls_rx_state rx_state;
-	/** Current received record header */
-	struct tls_header rx_header;
-	/** Current received record header (static I/O buffer) */
-	struct io_buffer rx_header_iobuf;
-	/** List of received data buffers */
-	struct list_head rx_data;
-	/** Received handshake fragment */
-	struct io_buffer *rx_handshake;
+	/** Transmit state */
+	struct tls_tx tx;
+	/** Receive state */
+	struct tls_rx rx;
 };
 
 /** RX I/O buffer size