#include <netinet/in.h>
/* Internet address */
sruct in_addr {
uint32_t s_addr; /* address in network byte order */
};
struct sockaddr_in {
sa_familt_t sin_family; /* address family: AF_INET */
in_port_t sin_port; /* port in network byte order */
struct in_addr sin_addr; /* internet address */
};
#include <sys/socket.h>
struct sockaddr {
sa_family_t sa_family; /* address family, AF_xxx */
char sa_data[14]; /* 14 bytes of protocol address */
};
#include <sys/types.h>
#include <sys/socket.h>
/* application to kernel */
int bind(int sockfd, const struct sockaddr* addr, socklen_t addrlen);
int connect(int sockfd, const struct sockaddr* addr, socklen_t addrlen);
ssize_t sendto(int sockfd, const void* buf, size_t len, int flags,
const struct sockaddr* dest_addr, socklen_t addrlen);
/* kernel to application */
int accept(int sockfd, struct sockaddr* addr, socklen_t* addrlen);
ssize_t recvfrom(int sockfd, void* buf, size_t len, int flags,
struct sockaddr* src_addr, socklen_t* addrlen);
int getsockname(int sockfd, struct sockaddr* addr, socklen_t* addrlen);
int getpeername(int sockfd, struct sockaddr* addr, socklen_t* addrlen);
/* Check if little endian or big endian. */
#include <stdio.h>
int main() {
union {
short s;
char c[sizeof(short)];
} un;
un.s = 0x0102;
if (sizeof(short) == 2) {
if (un.c[0] == 1 && un.c[1] == 2)
printf("big-endian\n");
else if (un.c[0] == 2 && un.c[1] == 1)
printf("little-endian\n");
else
printf("unknown\n");
} else
printf("sizeof(short) = %d\n", sizeof(short));
return 0;
}
#include <arpa/inet.h>
uint32_t htonl(uint32_t hostlong);
uint16_t htons(uint16_t hostshort);
uint32_t ntohl(uint32_t netlong);
uint16_t htons(uint16_t netshort);
#include <string.h>
void bzero(void* s, size_t n);
void bcopy(const void* src, void* dest, size_t n);
int bcmp(const void* s1, const void* s2, size_t n);
void* memset(void* s, int c, size_t n);
int memcmp(const void* s1, const void* s2, size_t n);
void* memcpy(void* dest, const void* src, size_t n);
#include <arpa/inet.h>
int inet_aton(const char* cp, struct in_addr *inp);
in_addr_t inet_addr(const char* cp);
char* inet_ntoa(struct in_addr in);
int inet_pton(int af, const char* src, void* dst);
const char* inet_ntop(int af, const void* src, char* dst, socklen_t size);
#include <unistd.h>
ssize_t write(int fd, const void* buf, size_t count);
ssize_t read(int fd, void* buf, size_t count);
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
int fstat(int fd, struct stat* buf);
#include <unistd.h>
int pid_t fork(void);
#include <unistd.h>
extern char** environ;
int execl(const char* path, const char* arg, ...);
int execlp(const char* file, const char* arg, ...);
int execle(const char* path, const char* arg, ..., char* const envp[]);
int execv(const char* path, char* const argv[]); /* system call */
int execvp(const char* file, char* const argv[]);
int execvpe(const char* file, char* const argv[], char* const envp[]);
![Figure 1](http://serika00.info/wp-content/uploads/2013/07/1.png)
![Figure 2](http://serika00.info/wp-content/uploads/2013/07/2.png)