Hello.

I need a little help with mbedtls 2.16.3. I'm using it under x86-64 with asio-standalone.

Here's a standard situation: - I call mbedtls_ssl_write() to write let's say 8192 bytes of payload - it calls my own bio_send() with (8192+21) bytes as len parameter - bio_send() returns len=(8192+21), indicating transport data correctly written - mbedtls_ssl_write() returns 8192, indicating payload send GOOD: next I use this value to shift application buffer (erase first 8192 bytes), then send next chunk

BUT after some time of running this situation happens: - once again, a call to mbedtls_ssl_write() to write let's say 8192 bytes of payload - it calls bio_send() with smaller number, about 5500 bytes as len parameter (?? but OK) - bio_send() returns len=5500, indicating transport data correctly written - mbedtls_ssl_write() returns 8192 (??? why not 5500 ???), indicating payload send BAD: next I use this value to shift application buffer (erase first 8192 bytes), this leads to data loss of (8192-5500)=2692 bytes and ruins protocol

As you can see, mbedtls_ssl_write() incorrectly reports about sent application data (8192 instead of 5500) - is this a bug? How can such situation happen under normal operation?

Thanks in advance.