ネットワーク・プログラミング（C言語）
Network Programming in C

第8回 12月4日
Lecture 8, December 4: Getting Caught Up

Outline of This Lecture

• Apologies
• Where you ought to be
• Structure of your system
• Homework

Apologies

I must apologize and take responsibility for several issues:

• Being slow to adapt to class experience level
• Behind in returning homeworks
• Compatibility problems among Linux, BSD, Mac, and cygwin

Where You Ought to Be

By now, you are supposed to be comfortable with the following tools:

• The C language
• Your C compiler
• A debugger
• make
• A wire analyzer (such as WireShark)

And the following concepts:

• Fundamentals of programming:
  • loops, recursion and control flow
  • data types and structures (structs, pointers, linked lists)
  • procedures, functions, and modular programming
  • memory management
• Fundamentals of software engineering:
  • Coding for maintainability: comments, simplicity, readability
  • Unit test
  • Regression testing
  • Version control, collaborative tools
• TCP/IP networking:
  • IPv4 and IPv6 addressing
  • TCP (stream, or connection-oriented) data transfer
  • UDP (datagram) data transfer
  • DNS
  • Sockets
  • Network byte order
  • Mixed binary and ASCII (text) data handling

...that's a lot for one semester.

Structure of Your System

By now, you should have a complete system fairly well under way. It should consist of the following:

• A makefile
• TCP server
• TCP client
• UDP server
• UDP client
• Basic library routines (mylib.c)
• A library of networking routines (networking.c)
• Module test files, mylibtest.c and networkingtest.c

宿題 10/9
Homework From Lecture 2

1. Begin your term project. Create three source files with the following functions:
   • hotpotato.c:
     main()
   • mylib.c:
     SleepALittle()
   • networking.c:
     OpenConnectionToServer()
   Compile and run your program. main() should call both SleepALittle() and OpenConnectionToServer(). The other two functions can be dummy functions for now.
2. Above, we defined the function MakeElementList(). Write a program including the function FreeElementList(), using the library function free().

宿題 10/16
Homework From Lecture 3

1. Last week, you were supposed to create three source files and link them together for your program. This week, we are going to add unit test. We need two more source code files:
   • mylibtest.c
   • networkingtest.c
   Each of those should include a main() function that calls each function in the corresponding source file to test that it works. Now you must compile three separate programs: hotpotato, mylibtest, and networkingtest. Show that each one runs.
2. The homework "answer" at the top of this page does not actually work. Please copy that to your computer, and debug it. (You may also want to use this as an opportunity to try a source code control system, such as RCS, and my preference is that you send me the solution to this problem as a diff or rcsdiff from the existing program.)

宿題 10/23
Homework From Lecture 4

1. Take the above program, and edit where the comments are to print out information about the connections, using getnameinfo(), getpeerinfo(), and gai_strerror().
2. Test for errors from the system calls in the above code. Use perror() where appropriate.
3. Modify the above server so that it calls fork() and creates a second process after accepting the connection. The parent should close() the connection socket and return to waiting for a new connection, while the child should close the initial socket, process the connection, then exit.
4. Learn to use a wire monitoring tool, such as Wireshark or tcpdump. Capture the packets of two connections to your server to show that both connections are being processed at the same time.