1 / 17

Network Programming

Network Programming. By J. H. Wang Nov. 21, 2011. Outline. Introduction to network programming Socket programming BSD Socket WinSock Java Socket Exercises. Introduction. Internet TCP/IP protocol stack Client-server model What do you need: client or server? Programming experience

vlora
Télécharger la présentation

Network Programming

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Network Programming By J. H. Wang Nov. 21, 2011

  2. Outline • Introduction to network programming • Socket programming • BSD Socket • WinSock • Java Socket • Exercises

  3. Introduction • Internet • TCP/IP protocol stack • Client-server model • What do you need: client or server? • Programming experience • C, C++, Java, … • Tools needed • C/C++/Java Compiler • Packet sniffers

  4. What’s a Socket • Source IP, port • Destination IP, port • Protocol • TCP • UDP • Connection method • Connection-oriented: SOCK_STREAM • Connectionless: SOCK_DGRAM

  5. Socket Programming • UNIX BSD socket (in C) • Windows socket (in Dev-C++) • Java socket API • Perl, Python, …

  6. Berkeley Socket • General functions • open(), connect(), close(), send(), recv(), … • Functions for servers • bind(), listen(), accept() • select(), FD_SET, FD_CLR, FD_ISSET, …

  7. An Example BSD Socket Program – a simple client (1/2) • #include <sys/socket.h>#include <netinet/in.h> // for struct sockaddr_in#include <netdb.h> // for gethostbyname()struct sockaddr_in dest;struct in_addr in;struct hostent *phe;char host[1000];int fd, port = 80;dest.sin_family=AF_INET;dest.sin_port = htons(port);if (phe = gethostbyname(host)) bcopy(phe->h_addr, (char *)&dest.sin_addr, phe->h_length);

  8. An Example BSD Socket Program – a simple client (2/2) • fd = socket(PF_INET, SOCK_STREAM, 0);in.s_addr = dest.sin_addr.s_addr;connect(fd, (struct sockaddr *)&dest, sizeof(dest));send(fd, msg, strlen(msg), 0);…recv(fd, buf, sizeof(buf), 0);…close(fd);

  9. Windows Socket • WSAStartup(), WSACleanup() • socket(), connect(), close() • send(), recv() • …

  10. An Example WinSock Client (1/2) • #include <winsock.h>SOCKET fd;SOCKADDR_IN dest;WSADATA WSAdata;struct hostent FAR *ent;int port = 80;WSAStartup(0x1010, &WSAdata);fd = socket(PF_INET, SOCK_STREAM, 0);dest.sin_family = PF_INET;dest.sin_port = htons(port);ent = gethostbyname(hostname);

  11. An Example WinSock Client (2/2) • connect(fd, (LPSOCKADDR)&dest, sizeof(SOCKADDR));send(fd, msg, strlen(msg), 0);…recv(fd, buf, sizeof(buf), 0);…close(fd);WSACleanup();

  12. Java Socket • java.net.Socket • new • getInputStream • getOutputStream • close • java.net.ServerSocket • new • accept • close

  13. An Example Java Socket Client (1/2) • import java.net.Socket;import java.net.InetSocketAddress;import java.io.BufferedOutputStream;import java.io.BufferedInputStream;public class SockClient { private String address = hostname; private int port = 80; public SockClient() { Socket client = new Socket(); InetSocketAddress isa = new InetSocketAddress(this.address, this.port);

  14. An Example Java Socket Client (2/2) • try { client.connect(isa, 10000); BufferedOutputStream out = new BufferedOutputStream(client.getOutputStream()); BufferedInputStream out = new BufferedInputStream(client.getInputStream());out.write(…);in.read(...);in.close();out.close();client.close();} catch () {}

  15. Response Parsing • Protocol dependent • browser • HTTP over TCP: connection-oriented • Byte ordering • Buffer management

  16. Programming Exercises • Packet sending/receiving • {Source, destination} (IP, port number) • Protocol • A simple HTTP client • To get a Web page at any URL • To display the page content

  17. Thanks for Your Attention!

More Related