[RFC 3/4] nvme/host/tcp: set max record size in the tls context

[Wilfred Mallawa <wilfred.opensource@gmail.com>]

From: Wilfred Mallawa <wilfred.mallawa@wdc.com>

During a tls handshake, a host may specify the tls record size limit
using the tls "record_size_limit" extension. Currently, the NVMe TCP
host driver does not specify this value to the tls layer.

This patch adds support for setting the tls record size limit into the
tls context, such that outgoing records may not exceed this limit
specified by the endpoint.

Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
---
 drivers/nvme/host/tcp.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 65ceadb4ffed..84a55736f269 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1677,6 +1677,7 @@ static void nvme_tcp_tls_done(void *data, int status, key_serial_t pskid,
 			      size_t tls_record_size_limit)
 {
 	struct nvme_tcp_queue *queue = data;
+	struct tls_context *tls_ctx = tls_get_ctx(queue->sock->sk);
 	struct nvme_tcp_ctrl *ctrl = queue->ctrl;
 	int qid = nvme_tcp_queue_id(queue);
 	struct key *tls_key;
@@ -1700,6 +1701,20 @@ static void nvme_tcp_tls_done(void *data, int status, key_serial_t pskid,
 			ctrl->ctrl.tls_pskid = key_serial(tls_key);
 		key_put(tls_key);
 		queue->tls_err = 0;
+
+		/* Endpoint has specified a maximum tls record size limit */
+		if (tls_record_size_limit > TLS_MAX_PAYLOAD_SIZE) {
+			dev_err(ctrl->ctrl.device,
+				"queue %d: invalid tls max record size limit: %zd\n",
+				nvme_tcp_queue_id(queue), tls_record_size_limit);
+			queue->tls_err = -EINVAL;
+			goto out_complete;
+		} else if (tls_record_size_limit > 0) {
+			tls_ctx->tls_record_size_limit = (u32)tls_record_size_limit;
+			dev_dbg(ctrl->ctrl.device,
+				"queue %d: target specified tls_record_size_limit %u\n",
+				nvme_tcp_queue_id(queue), tls_ctx->tls_record_size_limit);
+		}
 	}
 
 out_complete:
-- 
2.50.1