python: add initial support for Python

Signed-off-by: Shayne Sweeney <shayne@tailscale.com>

python/examples/echo.py

@@ -0,0 +1,42 @@
+# Copyright (c) Tailscale Inc & AUTHORS
+# SPDX-License-Identifier: BSD-3-Clause
+# TODO(shayne): proper select/poll/epoll + os.set_blocking(conn, False)
+import os
+import select
+from tailscale import TSNet
+
+def handler(conn):
+    while True:
+        r, _, _ = select.select([conn], [], [], 10)
+        if not conn in r:
+            os._exit(0)
+        data = os.read(conn, 2048)
+        print(data.decode(), end="")
+
+
+def main():
+    procs = []
+
+    ts = TSNet(ephemeral=True)
+    ts.up()
+
+    ln = ts.listen("tcp", ":1999")
+    while True:
+        while procs:
+            pid, exit_code = os.waitpid(-1, os.WNOHANG)
+            if pid == 0:
+                break
+            procs.remove(pid)
+
+        conn = ln.accept()
+        pid = os.fork()
+        if pid == 0:
+            return handler(conn)
+        procs.append(pid)
+
+    ln.close()
+    ts.close()
+
+
+if __name__ == "__main__":
+    main()