Calling nrf_send on TLS socket with large payload closing socket with errno -52 ENETRESET

RE: Calling nrf_send on TLS socket with large payload closing socket with errno -52 ENETRESET

Håkon Alseth — Mon, 16 Sep 2019 07:30:55 GMT

Hi,

[quote][/quote]

I have been digging around the NRFX documentation and headers and seen no mention of an upper limit to nrf_send, or how to adjust any buffers.

What is imposing this limit? Is there a way to know if our call to send is about to hit it before it kills our socket? How can I work around it?

This is lacking from our documentation.

The bsd_limits.h file shows 4k on a AT level: https://github.com/NordicPlayground/nrfxlib/blob/master/bsdlib/include/bsd_limits.h#L47

However, does not state anything about IP and TLS. I'll report this internally.

Just to confirm your suspicions; as per v1.0.x, the limit for TLS data is 2k.

Kind regards

Håkon

RE: Calling nrf_send on TLS socket with large payload closing socket with errno -52 ENETRESET

jbrzozoski — Fri, 13 Sep 2019 18:27:44 GMT

Here's a super-simple workaround. This patch is specific to MQTT, but the basic idea should work with any application. Just break one big send into lots of smaller ones...

This really is a bug in nrf_send, though...

diff --git a/subsys/net/lib/mqtt/mqtt_transport_socket_tls.c b/subsys/net/lib/mqtt/mqtt_transport_socket_tls.c
index 3ca6265760..97b3eeb366 100644
--- a/subsys/net/lib/mqtt/mqtt_transport_socket_tls.c
+++ b/subsys/net/lib/mqtt/mqtt_transport_socket_tls.c
@@ -120,7 +120,7 @@ int mqtt_client_tls_write(struct mqtt_client *client, const u8_t *data,

        while (offset < datalen) {
                ret = send(client->transport.tls.sock, data + offset,
-                          datalen - offset, 0);
+                          MIN(1024,(datalen - offset)), 0);
                if (ret < 0) {
                        return -errno;
                }