240-426 Unix Network Programming

Unix Network Programming
Computer Engineering: 240-426

Assignment 1 due date: December 26, 2003
Assignment 2 due date: March 1, 2004

Lecture 1:

Introduction to the Subject

Teaching methods, etc.

Assessment

Books

Review of Unix & System Calls

Lecture 2:

Unix I/O
System Calls
File Descriptors

Lecture 3:

Unix Device I/O
Pipes & other IPC
Protocols
The ISO Reference Model
ISORM Layers
Unix & network layers

Lecture 4:

Addressing
Link Level Addressing
Individual and Group Addresses
Network Addressing
Addressing for various protocols
IP addressing
Transport Addressing

Lecture 5:

Address Families
Connection Oriented and
Connectionless communications
Some Terminology
Client Network Process outline
Server Network Process outline
Creating a socket

Lecture 6:

Socket Addresses
Socket address storage
Various protocol sockaddrs

Lecture 7:

Number Representation
Network Byte Order
Conversion between Network Order and Host Order
Obtaining Addresses
The History
-- HOSTS.TXT and /etc/hosts
-- gethostbyname() and where it originated
-- extension to handle DNS queries
-- gethostbyname2() for IPv6, and why

Lecture 8:

gethostbyname() revision
-- and example usage
gethostbyname() and IPv6
gethostbyname2()
Becoming more portable
getaddrinfo() & friends
The addrinfo strcuture
Example getaddrinfo() for a client
Example getaddrinfo() for server
-- using the getaddrinfo hints

Lecture 9:

Manipulating addresses
getnameinfo()
inet_ntop() & inet_pton()
gethostbyadd4r() and IPv6
Accepting Connections
listen()
accept()
sample usage

Lecture 10:

Remaining pieces of simple client/server
closing sockets
-- close() & shutdown()
data transfer
-- read() & write()
-- recv() & send()
The Internet Daemon
Assignment 1 (copy available in PDF format)

Lecture 11:

Multiplexing I/O
-- the reason
-- operations that block
Traditional OS asynchronous I/O
Original unix method
-- fork() & one process per operation
-- limitations
ioctl solutions
-- FIONREAD
-- FIONBIO
-- FIOASYNC
requirement to eventually block
select()
File descriptor sets
-- operations upon them
-- introduction to select()

Lecture 12 & Lecture 13:

select() and how it works
-- Its disadvantages
poll() as an alternative to select
-- data structures
-- calling sequence & function
poll events
Working client/server examples
- client (trivial send & receive)
- simple server (one client at a time)
- simple forking server (fork for multiple clients)
- Demonstration of deadlock
- multiplexed server (select - avoids deadlocks)

Gzip'd Tarball of client & servers

Lecture 14

Datagrams, and their properties
sending datagrams: sendto()
Example of sendto()
Receiving datagrams: recvfrom()
Example datagram server
Dealing with the nature of datagrams
-- packet loss, duplication, reordering
Server behaviour
Client behaviour
Example datagram client
Connected datagram sockets
Datagram system call restrictions

Lecture 15

Revision for mid-term examination

Lecture 16

The Protocols
-- TCP UDP IP (and sockets)
Socket & protocol options
-- getsockopt()
-- getsockopt()
Some socket options

Lecture 17

Socket options for IP
Socket options for TCP
Socket options for UDP
Out of Band Data (intro)

Lecture 18

Out of Band Data
TCP Urgent Data
Unix facilities for dealing with OOB
Sending OOB data
Receiving OOB data

Lecture 19

Example of a network server
-- code walkthrough
C code available here

Lecture 20

Processing Unix Signals
Causes & types of signals
-- different default behaviours
Catching Signals
Signal Handlers
Caught signal inheritance (fork/exec)
Defined signal "handler" names
-- default, ignore & error return

Lecture 21

Signal Handler Functions
Interruptable system calls
Race Conditions
-- internal to library functions
Safe signal handler code
Catching Signals
Avoiding Race Conditions
Inapplicability of semaphores & critical regions to interrupt routines
Blocking Signals

Lecture 22

Assignment 2 (copy available in PDF format)

Lecture 23

Other IPC forms
Shared memory, mmap and shm
mmap interface & mapped files
Semaphores
System V messages
Pseudo Terminals
-- rationale & function
Pseudo terminal operations
Allocating a pty
Cloning devices