Hands-On Network Programming with C

TCP program flow

A TCP client program must first know the TCP server's address. This is often input by a user. In the case of a web browser, the server address is either input directly by the user into the address bar, or is known from the user clicking on a link. The TCP client takes this address (for example, http://example.com) and uses the getaddrinfo() function to resolve it into a struct addrinfo structure. The client then creates a socket using a call to socket(). The client then establishes the new TCP connection by calling connect(). At this point, the client can freely exchange data using send() and recv().

A TCP server listens for connections at a particular port number on a particular interface. The program must first initialize ...