1. Network Programming with Sockets
Reading: Chapter 27
Fall 2004
FSU CIS 5930 Internet Protocols

2. FSU CIS 5930 Internet Protocols
Sockets
A common/popular network programming interface to access transport protocols
Data structures
Functions
Fall 2004
FSU CIS 5930 Internet Protocols

3. FSU CIS 5930 Internet Protocols
Socket addresses
typedef unsigned short sa_family_t;
struct sockaddr {
sa_family_t sa_family;
char sa_data[14]; };
struct in_addr {
__u32 s_addr;
struct sockaddr_in {
sa_family_t sin_family; /* Address family */
unsigned short int sin_port; /* Port number */
struct in_addr sin_addr; /* Internet address */
/* Pad to size of `struct sockaddr'. */
unsigned char __pad[__SOCK_SIZE__ - sizeof(short int) –
sizeof(unsigned short int) –
sizeof(struct in_addr)];
Fall 2004
FSU CIS 5930 Internet Protocols

4. Socket operations Fall 2004 FSU CIS 5930 Internet Protocols socket()
listen()
bind()
accept()
close()
connect()
Connection establishment
Data exchange
Server
Client
read()
recv()
recvfrom()
readv()
recvmsg()
write()
send()
sendto()
writev()
sendmsg()
Fall 2004
FSU CIS 5930 Internet Protocols

5. Byte ordering methods Little-endian vs. big-endian Functions
htonl(), htons(), ntohl(), ntohs()
Most significant byte 0xAA
Least significant byte 0xBB
Least significant byte
0xBB
Most significant byte 0xAA
0x1000
0x1001
Big-Endian (Network-Byte-Order)
Little-Endian
Memory address
Fall 2004
FSU CIS 5930 Internet Protocols

6. Functions to handle Internet addresses
Dotted decimal notation vs. Internet address (in_addr)
inet_addr(), inet_aton(), inet_ntoa(), inet_ntop(), inet_pton()
Others
getpeername(), get the IP address of the peer
gethostname(), get name of local host
gethostbyname(), get host IP address, given name
Fall 2004
FSU CIS 5930 Internet Protocols