tls: rx: factor out writing ContentType to cmsg

cmsg can be filled in during rx_list processing or normal
receive. Consolidate the code.

We don't need to keep the boolean to track if the cmsg was
created. 0 is an invalid content type.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tls/tls_sw.c

@@ -1635,6 +1635,29 @@ static bool tls_sw_advance_skb(struct sock *sk, struct sk_buff *skb,
 	return true;
 }
 
+static int tls_record_content_type(struct msghdr *msg, struct tls_msg *tlm,
+				   u8 *control)
+{
+	int err;
+
+	if (!*control) {
+		*control = tlm->control;
+		if (!*control)
+			return -EBADMSG;
+
+		err = put_cmsg(msg, SOL_TLS, TLS_GET_RECORD_TYPE,
+			       sizeof(*control), control);
+		if (*control != TLS_RECORD_TYPE_DATA) {
+			if (err || msg->msg_flags & MSG_CTRUNC)
+				return -EIO;
+		}
+	} else if (*control != tlm->control) {
+		return 0;
+	}
+
+	return 1;
+}
+
 /* This function traverses the rx_list in tls receive context to copies the
  * decrypted records into the buffer provided by caller zero copy is not
  * true. Further, the records are removed from the rx_list if it is not a peek
@@ -1643,31 +1666,23 @@ static bool tls_sw_advance_skb(struct sock *sk, struct sk_buff *skb,
 static int process_rx_list(struct tls_sw_context_rx *ctx,
 			   struct msghdr *msg,
 			   u8 *control,
-			   bool *cmsg,
 			   size_t skip,
 			   size_t len,
 			   bool zc,
 			   bool is_peek)
 {
 	struct sk_buff *skb = skb_peek(&ctx->rx_list);
-	u8 ctrl = *control;
-	u8 msgc = *cmsg;
 	struct tls_msg *tlm;
 	ssize_t copied = 0;
-
-	/* Set the record type in 'control' if caller didn't pass it */
-	if (!ctrl && skb) {
-		tlm = tls_msg(skb);
-		ctrl = tlm->control;
-	}
+	int err;
 
 	while (skip && skb) {
 		struct strp_msg *rxm = strp_msg(skb);
 		tlm = tls_msg(skb);
 
-		/* Cannot process a record of different type */
-		if (ctrl != tlm->control)
-			return 0;
+		err = tls_record_content_type(msg, tlm, control);
+		if (err <= 0)
+			return err;
 
 		if (skip < rxm->full_len)
 			break;
@@ -1683,27 +1698,12 @@ static int process_rx_list(struct tls_sw_context_rx *ctx,
 
 		tlm = tls_msg(skb);
 
-		/* Cannot process a record of different type */
-		if (ctrl != tlm->control)
-			return 0;
-
-		/* Set record type if not already done. For a non-data record,
-		 * do not proceed if record type could not be copied.
-		 */
-		if (!msgc) {
-			int cerr = put_cmsg(msg, SOL_TLS, TLS_GET_RECORD_TYPE,
-					    sizeof(ctrl), &ctrl);
-			msgc = true;
-			if (ctrl != TLS_RECORD_TYPE_DATA) {
-				if (cerr || msg->msg_flags & MSG_CTRUNC)
-					return -EIO;
-
-				*cmsg = msgc;
-			}
-		}
+		err = tls_record_content_type(msg, tlm, control);
+		if (err <= 0)
+			return err;
 
 		if (!zc || (rxm->full_len - skip) > len) {
-			int err = skb_copy_datagram_msg(skb, rxm->offset + skip,
+			err = skb_copy_datagram_msg(skb, rxm->offset + skip,
 						    msg, chunk);
 			if (err < 0)
 				return err;
@@ -1740,7 +1740,6 @@ static int process_rx_list(struct tls_sw_context_rx *ctx,
 		skb = next_skb;
 	}
 
-	*control = ctrl;
 	return copied;
 }
 
@@ -1762,7 +1761,6 @@ int tls_sw_recvmsg(struct sock *sk,
 	struct tls_msg *tlm;
 	struct sk_buff *skb;
 	ssize_t copied = 0;
-	bool cmsg = false;
 	int target, err = 0;
 	long timeo;
 	bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
@@ -1779,8 +1777,7 @@ int tls_sw_recvmsg(struct sock *sk,
 	bpf_strp_enabled = sk_psock_strp_enabled(psock);
 
 	/* Process pending decrypted records. It must be non-zero-copy */
-	err = process_rx_list(ctx, msg, &control, &cmsg, 0, len, false,
-			      is_peek);
+	err = process_rx_list(ctx, msg, &control, 0, len, false, is_peek);
 	if (err < 0) {
 		tls_err_abort(sk, err);
 		goto end;
@@ -1852,25 +1849,9 @@ int tls_sw_recvmsg(struct sock *sk,
 		 * is known just after record is dequeued from stream parser.
 		 * For tls1.3, we disable async.
 		 */
-
-		if (!control)
-			control = tlm->control;
-		else if (control != tlm->control)
-			goto recv_end;
-
-		if (!cmsg) {
-			int cerr;
-
-			cerr = put_cmsg(msg, SOL_TLS, TLS_GET_RECORD_TYPE,
-					sizeof(control), &control);
-			cmsg = true;
-			if (control != TLS_RECORD_TYPE_DATA) {
-				if (cerr || msg->msg_flags & MSG_CTRUNC) {
-					err = -EIO;
+		err = tls_record_content_type(msg, tlm, &control);
+		if (err <= 0)
 			goto recv_end;
-				}
-			}
-		}
 
 		if (async) {
 			/* TLS 1.2-only, to_decrypt must be text length */
@@ -1953,10 +1934,10 @@ int tls_sw_recvmsg(struct sock *sk,
 
 		/* Drain records from the rx_list & copy if required */
 		if (is_peek || is_kvec)
-			err = process_rx_list(ctx, msg, &control, &cmsg, copied,
+			err = process_rx_list(ctx, msg, &control, copied,
 					      decrypted, false, is_peek);
 		else
-			err = process_rx_list(ctx, msg, &control, &cmsg, 0,
+			err = process_rx_list(ctx, msg, &control, 0,
 					      decrypted, true, is_peek);
 		if (err < 0) {
 			tls_err_abort(sk, err);