Currently, to send early data the client application calls mbedtls_ssl_set_early_data() before the handshake begins, with a pointer to the early data buffer. Once set, the early data buffer cannot be changed during the handshake, limiting the client application to a single early data payload and reducing the opportunity to take full advantage of early data.
Consider a streaming app for example, where real-time data is generated simultaneously with the handshake. The new API will support streaming early data throughout the duration of the handshake in accordance with the standard:
Clients are permitted to "stream" 0-RTT data until they receive the server's Finished, only then sending the EndOfEarlyData message, followed by the rest of the handshake.
Status
DRAFT, solicit feedback on design.
Requires Backporting
NO
Additional comments
Credit to @zhihan for setting the foundation for this work, and @lhuang04 for offering feedback.
I left the existing early data API untouched for now, anticipating it will eventually be removed. The new API can be enabled thru mbedtls_ssl_conf_early_data().
This branch is based off #386 in order to enable adding tests for the early data rejected case.
Description
This PR adds a new API for sending early data, building off the work done in https://github.com/hannestschofenig/mbedtls/pull/369.
Background
Currently, to send early data the client application calls
mbedtls_ssl_set_early_data()before the handshake begins, with a pointer to the early data buffer. Once set, the early data buffer cannot be changed during the handshake, limiting the client application to a single early data payload and reducing the opportunity to take full advantage of early data.Consider a streaming app for example, where real-time data is generated simultaneously with the handshake. The new API will support streaming early data throughout the duration of the handshake in accordance with the standard:
Status
DRAFT, solicit feedback on design.
Requires Backporting
NO
Additional comments
mbedtls_ssl_conf_early_data().Todos
Steps to test or reproduce
ssl-opt.sh -f 'early data'