extmod/asyncio: Add ssl support with SSLContext.

This adds asyncio ssl support with SSLContext and the corresponding
tests in `tests/net_inet` and `tests/multi_net`.

Note that not doing the handshake on connect will delegate the handshake to
the following `mbedtls_ssl_read/write` calls.  However if the handshake
fails when a client certificate is required and not presented by the peer,
it needs to be notified of this handshake error (otherwise it will hang
until timeout if any).  Finally at MicroPython side raise the proper
mbedtls error code and message.

Signed-off-by: Carlos Gil <carlosgilglez@gmail.com>

1 files changed, 77 insertions, 0 deletions

diff --git a/tests/multi_net/asyncio_tls_server_client_readline.py b/tests/multi_net/asyncio_tls_server_client_readline.py
new file mode 100644
index 0000000000..28add38f5d
--- /dev/null
+++ b/tests/multi_net/asyncio_tls_server_client_readline.py
@@ -0,0 +1,77 @@
+# Test asyncio TCP server and client with TLS, using readline() to read data.
+
+try:
+    import os
+    import asyncio
+    import ssl
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+PORT = 8000
+
+# These are test certificates. See tests/README.md for details.
+cert = cafile = "multi_net/rsa_cert.der"
+key = "multi_net/rsa_key.der"
+
+try:
+    os.stat(cafile)
+    os.stat(key)
+except OSError:
+    print("SKIP")
+    raise SystemExit
+
+
+async def handle_connection(reader, writer):
+    data = await reader.readline()
+    print("echo:", data)
+    data2 = await reader.readline()
+    print("echo:", data2)
+    writer.write(data + data2)
+    await writer.drain()
+
+    print("close")
+    writer.close()
+    await writer.wait_closed()
+
+    print("done")
+    ev.set()
+
+
+async def tcp_server():
+    global ev
+
+    server_ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
+    server_ctx.load_cert_chain(cert, key)
+    ev = asyncio.Event()
+    server = await asyncio.start_server(handle_connection, "0.0.0.0", PORT, ssl=server_ctx)
+    print("server running")
+    multitest.next()
+    async with server:
+        await asyncio.wait_for(ev.wait(), 10)
+
+
+async def tcp_client(message):
+    client_ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
+    client_ctx.verify_mode = ssl.CERT_REQUIRED
+    client_ctx.load_verify_locations(cafile=cafile)
+    reader, writer = await asyncio.open_connection(
+        IP, PORT, ssl=client_ctx, server_hostname="micropython.local"
+    )
+    print("write:", message)
+    writer.write(message)
+    await writer.drain()
+    data = await reader.readline()
+    print("read:", data)
+    data2 = await reader.readline()
+    print("read:", data2)
+
+
+def instance0():
+    multitest.globals(IP=multitest.get_network_ip())
+    asyncio.run(tcp_server())
+
+
+def instance1():
+    multitest.next()
+    asyncio.run(tcp_client(b"client data\nclient data2\n"))