Network Programming CSC- 341

1. Network ProgrammingCSC- 341 Instructor: Junaid Tariq, Lecturer, Department of Computer Science

2. 12 Lecture Network Programming

3. Part 2 Sockets IntroductionChapter 3

4. Byte Manipulation Functions • #include <strings.h> void bzero(void *dest, size_t nbytes); /* sets the specified no of bytes to zero */ void bcopy(const void *src, void *dest, size_t nbytes); /* byte by byte copy from source to destination */ int bcmp(const void *ptr1, const void *ptr2, size_t nbytes); /* return 0 if equal, nonzero if unequal */

5. BZERO

6. BCOPY

7. BCMP

8. Byte Manipulation Functions Cont. • #include <string.h> void *memset(void *dest, int c, size_t len); /* sets specified no of bytes to ‘c’ */ void *memcpy(void *dest, const void *src, size_t nbytes); /* byte string copy from source to destination but undefined if source and destination buffers overlap*/ int memcmp(const void *ptr1, const void *ptr2, size_t nbytes); /* ptr1 < ptr2 : less than 0 (for first unequal bytes) ptr1 > ptr2 : greater than 0 (for first unequal bytes) ptr1 = ptr2 : than 0 Each bytes is considered as unsigned char */

9. 3.6 inet_aton,inet_addr, inet_ntoa functions • Convert internet address between ASCII string and network byte ordered binary values(as stored in socket address structure) • Used for IPv4 addresses conversion • For both IPv4 and IPv6 we have : inet_pton , inet_ntop

10. #include<arpa/inet.h> For ASCII to network binary: int inet_aton(const char *strptr, struct in_addr *addrptr); /* return : 1 if successful,0 on error */ For ASCII to network binary: in_addr_t inet_addr(const char *strptr); /* return : 32bit binary network byte ordered IPv4 address; INADDR_NONE (32 one-bits) if error */ For network binary to ASCII: char *inet_ntoa(struct in_addr inaddr); /*return pointer to dotted-decimal string*/

11. ATON & NTOA

12. 3.7 inet_pton,inet_ntopfunction • Both IPv4,IPv6 address conversion • p : presentation(string) n : numeric(binary) • #include<arpa/inet.h> int inet_pton(int family, const char *strptr, void *addrptr); /* return: 1 if OK, 0 if input not a valid presentation format, -1 if family not supported */ const char *inet_ntop(int family, const void *addrptr, char *strpt, size_t len); /* return : pointer to result if OK, NULL if length allocated for string is smaller then required size, 16 for IPv4 dotted decimal and 46 for IPv6 hex*/ /* len : size of the destination string allocated by the caller*/

13. PTON & NTOP