Protean Protocol Prototyping Library (PROTOLIB)

OVERVIEW

Protolib is not so much a library as it is a toolkit. The goal of the Protolib is to provide a set of simple, cross-platform C++ classes that allow development of network protocols and applications that can run on different platforms and in network simulation environments. Although Protolib is principally for research purposes, the code has been constructed to provide robust, efficient performance and adaptability to real applications.

Currently Protolib supports most Unix platforms (including MacOS X) and WIN32 platforms. The most recent version also supports building Protolib-based code for the ns-2 simulation environment. The OPNET simulation tool has also been supported in the past and could be once again with a small amount of effort.

CLASSES:

ProtoAddress: Network address container class with support for IPv4, IPv6, and "SIM" address types. Also includes functions for name/address resolution.

ProtoSocket: Network socket container class that provides consistent interface for use of operating system (or simulation environment) transport sockets. Provides support for asynchronous notification to ProtoSocket::Listeners. The ProtoSocket class may be used stand-alone, or with other classes described below. A ProtoSocket may be instantiated as either a UDP or TCP socket.

ProtoTimer: This is a generic timer class which will notify a ProtoTimer::Listener upon timeout.

ProtoTimerMgr: This class manages ProtoTimer instances when they are "activated". The ProtoDispatcher (below) derives from this to manage ProtoTimers for an application. (The ProtoSimAgent base class contains a ProtoTimerMgr to similarly manage timers for a simulation instance).

ProtoList: Basic linked list data structure, but is a ProtoIterable that enables the list to be updated within ProtoList::Iterator loops, etc. A template class ProtoListTemplate is provided to make it easy to create lists of user-defined ProtoList::Item subclass types.

ProtoTree: Flexible implementation of a Patricia tree data structure. Includes a ProtoTree::Item which may be derived from or used as a container for whatever data structures and application may require. A template class ProtoListTemplate is provided to make it easy to create lists of user-defined ProtoList::Item subclass types. Also ProtoSortedTree is provided as a threaded Patricia tree that allows multiple entries for the same key value with controls to allow sorting and closest match search even for items indexed with numeric (int, double, etc) vslues.

ProtoQueue: A slightly heavier weight derivation from the basic ProtoList and ProtoTree data structures. Unlike ProtoList::Item or ProtoTree::Item instances that are limited to exclusive inclusion in a single list or tree, ProtoQueue:Item instances may be members of multiple ProtoQueues. Queue variants include ProtoSimpleQueue - linked list usable for FIFO, stack, etc ProtoIndexedQueue - ProtoTree of queue items indexed by a key ProtoSortedQueue - ProtoSortedTree of queue items. Again, template classes are provided these to make it easy to create and manage user-derived ProtoQueue::Item types.

ProtoRouteTable: Class based on the ProtoTree Patricia tree to store routing table information. Uses the ProtoAddress class to store network routing addresses. It's a pretty dumbed-down routing table at the moment, but may be enhanced in the future. Example use of the ProtoTree.

ProtoRouteMgr: Base class for providing a consistent interface to manage operating system (or other) routing engines.

ProtoPipe: Socket-like mechanism (with both datagram and stream support) useful for interprocess communications (uses Unix domain sockets on Unix, other stuff on Win32 & WinCE)

ProtoCap: Interface class for raw MAC-layer packet capture. Platform implementations of this class vary including a "pcap" based implementation.

ProtoDetour: Inbound/outbound packet interception class. Platform implementations vary ... works with firewall stuff. Win32 version based around NDIS intermediate driver in progress.

ProtoDispatcher: This class provides a core around which Unix and Win32 applications using Protolib can be implemented. It's "Run()" method provides a "main loop" which uses the "select()" system call on Unix and the similar "MsgWaitForMultipleObjectsEx()" system call on Win32. It is planned to eventually provide some built-in support for threading in the future (e.g. the ProtoDispatcher::Run() method might execute in a thread, dispatching events to a parent thread).

ProtoApp: Provides a base class for implementing Protolib-based command-line applications. Note that "ProtoApp" and "ProtoSimAgent" are designed such that subclasses can be derived from either to reuse the same code in either a real-world applications or as an "agent" (entity) within a network simulation environment (e.g. ns-2, OPNET). A "background" command is included for Win32 to launch the app without a terminal window.

ProtoSimAgent: Base class for simulation agent derivations. Currently an ns-2 agent base class is derived from this, but it is possible that other simulation environments (e.g. OPNET, Qualnet) might be supported in a similar fashion.

NsProtoSimAgent: Simulation agent base class for creating ns-2 instantiations of Protolib-based network protocols and applications.

ProtoExample: Example class which derives either from ProtoApp or NsProtoSimAgent, depending upon compile-time macro definitions. It provides equivalent functionality in either the simulation environment or as a real-world command-line application. It demonstrates the use/operation of ProtoSocket based UDP transmission/reception, a ProtoTimer, and an example ProtoSocket-based TCP client-server exchange. (NOTE: TCP operation is not yet supported in the simulation environment. This will completed in coming months. I plan to extend ns-2 TCP agents to support actual transfer of user data to support this.)

NsProtoTCPSocketAgent: TCP implementation of the NSSocketProxy class for providing TCP support within Protolib.
This class provides a hub for interfacing with the underlying TCP toolkit for providing access to the TCP support. NsProtoTCPSocketAgent essentially auto-detects which sockets it should be (i.e. a client or a server) and then instantiates the underlying implementations in order to provide that behaviour, which are either a TCPSocketAgent or a TCPServerSocketAgent:

TCPSocketAgent: The TCP socket agent implementation that can be used for clients and that can be used as the socket responsible for the server-side of the connection after a call to accept.

TCPServerSocketAgent: The TCP server implementation that only implements part of the TCP protocol (by listening for the initial SYN connection requests from clients).
The server simply acts as a broker for assigning TCPSocketAgents when clients request connections, either by creating the sockets itself or by sending an ACCEPT event to the application in order for it to create the socket and call the accept function manually. The latter approach is the norm.

OTHER:

The Protolib code also includes some simple, general purpose debugging routines which can output to "stderr" or optionally log to a specified file. See "protoDebug.h" for details.

There are also some supporting classes not described here and some work to be done. Also, more complete documentation, including Doxygen-based code documentation and a "Developer's Guide" with examples needs to be provided.