1 / 9

Advanced Sockets

This course, led by Prof. Aleksandar Kuzmanovic and TA John Otto, provides an introduction to advanced sockets and networking principles. Learn about handling incoming connections, blocking functions, and the select call for managing multiple clients simultaneously. The lecture covers practical examples and code snippets to enhance your understanding of networking concepts. Geet Duggal offers support via office hours. Improve your server skills and efficiency in dealing with various sockets with this comprehensive guide.

elma
Download Presentation

Advanced Sockets

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. Introduction to Networking Instructor: Prof. Aleksandar Kuzmanovic Advanced Sockets John Otto TA , Intro to Networking Jan 24, 2007 Recital 3

  2. Homework grader • Geet Duggal, geet@geetduggal.com. • Office hours on Tuesdays between 4 and 6

  3. The problem You are a server and you want to listen for incoming connections as well as keep reading from the connections you already have. • Blocking • "block" is techie jargon for "sleep". • Lots of functions block. • accept() blocks. • All the recv() functions block

  4. The select call Enables you to deal with many clients at the same time HOW ? Monitors several sockets at the same time. tell you which ones are ready for reading, which are ready for writing,

  5. Synopsis of select() • #include <sys/time.h> • #include <sys/types.h> • #include <unistd.h> • int select(int numfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout); • It'll tell you which ones are ready for reading, which are ready for writing, and which sockets have raised exceptions, if you really want to know that.

  6. Manipulate sets • Each set is of the type fd_set. The following macros operate on this type: • FD_ZERO(fd_set *set) -- clears a file descriptor set • FD_SET(int fd, fd_set *set) -- adds fd to the set • FD_CLR(int fd, fd_set *set) -- removes fd from the set • FD_ISSET(int fd, fd_set *set) -- tests to see if fd is in the set • Example - when select() returns, readfds will be modified to reflect which of the file descriptors you selected is ready for reading. Test them with the macro FD_ISSET(),

  7. THE CODE A multi-person chat server

  8. DEMO A multi-person chat server

  9. Important Points • Accepting new connections via select • Client closes connection • Select returns “socket ready to read” • recv() will return 0.

More Related