Design Flaws in doscan
----------------------

Despite its small size, doscan contains several design flaws which are
somewhat hard to address at this point.

  * Error reporting is rather poor.  The reporting engine in
    src/result.{h,cc} has hardly been modified since the switch from C
    to C++.  A complete rewrite is necessary for more accurate
    reporting of errors.

  * Scanning modules are harder to write than expected.  The
    single-threaded, non-blocking I/O design of doscan is certainly
    quite performant (as it minimizes context switches), but it's too
    hard to write moderately complex protocol modules.  The HTTP
    client/server code is a bad example.  The current interfaces are
    also somewhat error-prone (unbounded memory allocation can occur
    if the protocol module is not written carefully).

  * The connect() rate limiting needs a complete overhaul.  It's
    likely that we stress the network more than necessary because we
    do not adequately distribute connect() calls in time.

And finally, C++ is an unsafe programming language.  Buffer overflows
lurk at almost every corner.