TOC

• mp0 intro to socket programming
• mp1 http server
• mp2 tcp
• mp3 routing algorithm
• mp4 csma

MP0

Remember, any thing is a file under Unix.

Step by Step

0. On every step do error checking on return value and perror() it.
1. getaddrinfo() Fill the struct addrinfo
2. socket() Get the file descriptor
3. bind() Associate the socket with a port on your local machine
4. connect() Connect to a remote host.
5. listen() Wait for incoming connections and set backlog
6. accept() Handle the connections and get new socket descriptor(fork a new socket for every connection).
7. send() and recv() Talk to me, baby and be careful about the return value.
8. sendto() and recvfrom() Talk to me, DGRAM-style.Used for unconnected datagram sockets
9. close() and shutdown() Shutdown() change socket's usability while close() free a socket descriptor.
10. getpeername() and gethostname() Who are you? Who am I?

Struct

struct	function	notes
struct addrinfo	getaddrinfo() and freeaddrinfo()	struct sockaddr *ai_addr
struct sockaddr		can be cast into/back sockaddr_in or sockaddr_in6
struct sockaddr_in	inet_pton(AF_INET, ipv4 string, struct sockaddr_in *) and its brother inet_ntop	struct in_addr sin_addr
struct sockaddr_in6	inet_pton(AF_INET6, ipv6 string, struct sockaddr_in6 *) and its brother inet_ntop	struct in6_addr sin6_addr
struct sockaddr_storage		check ss_familt and cast it to according socket address struct

Notes

1. If you see something like this: Makefile:66: *** missing separator. Stop. Makefile expect command is indented by tab other than space, so you maybe use \t or use tab.
2. TCP and UDP can use same port.

MP1

• Use strlen() instead of sizeof().
• CRLF = CR LF
• HTTP Response
  • Request line, such as GET /logo.gif HTTP/1.1 or Status line, such as HTTP/1.1 200 OK,
  • Headers
  • An empty line
  • Optional HTTP message body data

The request/status line and headers must all end with <CR><LF> (that is, a carriage return followed by a line feed). The empty line must consist of only and no other whitespace.

• Don't set const too small