Sockaddr we dont need to deal with sockaddr

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Unformatted text preview: don’t need to deal with sockaddr structures structures since we will only deal with a real protocol family. • We can use sockaddr_in structures. sockaddr_in structures. TCP/IP TCP/IP Addresses 30 sa_data ECEN 602 Socket Programming sin_len AF_INET sa_len sa_family sin_zero sin_addr sin_port sockaddr_in sockaddr 31 ECEN 602 Socket Programming • bind returns 0 if successful or -1 on error. int bind( int sockfd, const const struct sockaddr *myaddr, int int addrlen); const! bind() • The bind() system call is used to assign an address to an existing socket. Assigning Assigning an address to a socket 32 ECEN 602 Socket Programming bind( mysock, (struct sockaddr*) &myaddr, sizeof(myaddr) ); • calling bind() assigns the address bind() specified by the sockaddr structure to sockaddr the socket descriptor. • You can give bind() a sockaddr_in bind() sockaddr_in structure: bind() bind() 33 ECEN 602 Socket Programming err=bind(mysock, (sockaddr *) &myaddr, sizeof(myaddr)); mysock = socket(PF_INET,SOCK_STREAM,0); myaddr.sin_family = AF_INET; myaddr.sin_port = htons( portnum ); myaddr.sin_addr = htonl( ipaddress); int mysock,err; struct sockaddr_in myaddr; bind() bind() Example 34 ECEN 602 Socket Programming – Client can ask the O.S. to assign any any available port number. – Client can bind to a specific port. – Server would like to bind to a well known address address (port number). bind() • There are a number of uses for bind(): Uses Uses for bind() bind() 35 ECEN 602 Socket Programming myaddr.port = htons(0); • Clients typically don’t care what port they are assigned. • When you call bind you can tell it to assign assign you any available port: Client Client Port 36 ECEN 602 Socket Programming • specify the IP address as: INADDR_ANY, INADDR_ANY this this tells the OS to take care of things. • Th...
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This document was uploaded on 01/29/2014.

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