VPP/HostStack/TLS
From fd.io
TLS App
TLS service is offered by the stack to other client applications via a custom builtin application. The TLS application implements a special transport type that allows it to behave as an application, from the underlying TCP transport perspective, but also as a transport, from the client application perspective. The app does not directly implement the TLS protocol, i.e., the record layer, handshaking protocols and the cryptographic computations and suites, instead it relies on the mbedtls library.