+ What is tapip?
   A mutlithreaded TCP/IP stack based on linux tap device

+ Dependence?
  linux tun/tap device (/dev/net/tun exists if supported)
  pthreads

+ How to run?
  Quick start:
    $ make
    # ./tapip                    (run as root)
    [net shell]: ping 10.0.0.2   (ping linux kernel TCP/IP stack)
    (waiting icmp echo reply...)
    [net shell]: help            (see all embedded commands)
    ...

  More information for hacking TCP/UDP/IP/ICMP:
    See doc/net_topology, and select a script from doc/test to do.

+ Socket Api?
  _socket,_read,_write,_send,_recv,_connect,_bind,_close and _listen
   are provided now.
  Three socket types(SOCK_STREAM, SOCK_DGRAM, SOCK_RAW) can be used.
  You can use these apis to write applications working on tapip.
  Good examples are app/ping.c and app/snc.c.

+ How to implement?
   I refer to xinu and Linux 2.6.11 TCP/IP stack
    and use linux tap device to simulate net device(for l2).
   A small shell is embedded in tapip.
   So this is just user-mode TCP/IP stack :)

+ Any use?
  A toy!
  Tapip makes it easy to hack TCP/IP stack, just compiling it to run.
  It can also do some network test: arp snooping, proxy, and NAT!
  I think the most important is that tapip helps me learn TCP/IP, and
   understand linux TCP/IP stack.

+ Author?
  Xiaochen Wang <wangxiaochen0@gmail.com>