[lwip-devel] [bug #52836] altcp_write error because of invalid sndbuf available returned

[David GIRAULT]

URL:
  <http://savannah.nongnu.org/bugs/?52836>

                 Summary: altcp_write error because of invalid sndbuf
available returned
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: dgirault
            Submitted on: Mon 08 Jan 2018 02:12:42 PM UTC
                Category: apps
                Severity: 3 - Normal
              Item Group: None
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None
            lwIP version: git head

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Details:

While using MQTT over an SSL connexion, using MQTT_OUTPUT_RINGBUF_SIZE ==
8192, we got error when altcp_write() when our MQTT message reach 2*MSS.

mbedTLS version of altcp API use altcp_default_sndbuf() which return
tcp_sendbuf(), but when writing using this max value on a altcp_mbedtls
socket, this return an error because the generated ciphered version of the
message is greater than the tcp_sndbuf() of lower TCP socket.

This patch add a new altcp_mbedtls_sndbuf() implementation that take care of
record header and more data added by TLS to data to be sent.



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File Attachments:


-------------------------------------------------------
Date: Mon 08 Jan 2018 02:12:42 PM UTC  Name: altcp_mbedtls_sndbuf.patch  Size:
2KiB   By: dgirault

<http://savannah.nongnu.org/bugs/download.php?file_id=42870>

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