Linux C socket 基于 UDP

/*************************************************************************
    > File Name: server.c
    > Author: Stomach_ache
    > Mail: 1179998621@qq.com 
    > Created Time: 2014年02月25日 星期二 08时17分13秒
    > Propose: 
 ************************************************************************/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <linux/in.h>


#define KEY ("request!")
#define MAX_SIZE 1024


int 
main(int argc, char **argv)
{
int sfp;
struct sockaddr_in s_add, c_add;
int sin_size;
int recbytes;
char buffer[MAX_SIZE];
unsigned short portnum = 0x8888;

printf("Hello, welcome to my server! ");

//创建一个套接字，类型使用：SOCK_DGRAM，它的默认协议是UDP

sfp = socket(AF_INET, SOCK_DGRAM, 0);
if (-1 == sfp) {
printf("socket fail! ");
return -1;
}
printf("socket ok! ");

//好像比较推荐使用memset而不是bzero
bzero(&s_add, sizeof(struct sockaddr_in));
s_add.sin_family = AF_INET;
s_add.sin_addr.s_addr= htonl(INADDR_ANY);
s_add.sin_port = htons(portnum);

//套接字和地址绑定
if (-1 == bind(sfp, (struct sockaddr *)(&s_add), sizeof(struct sockaddr))) {
printf("bind fail! ");
return -1;
}
printf("bind ok! ");


int len = sizeof(c_add);


while (1) {


if (-1 == (recbytes = recvfrom(sfp, buffer, 1024, 0,
  (struct sockaddr*)&c_add,
  &len))) {
printf("read data fail! ");
return -1;
}
//printf("read ok! REC: ");
buffer[recbytes] = '';
/* printf("%s ", buffer); */
if (0 == strcmp(buffer, KEY)) {
printf("key is right! ");
if (-1 == sendto(sfp, "you are an idiot! ", 32, 0,
(struct sockaddr*)&c_add,
sizeof(c_add))) {
printf("write fail! ");
return -1;
}
printf("write ok! ");
}
/* close(nfp); */
}

close(sfp);
return 0;

}

/*************************************************************************
    > File Name: client.c
    > Author: Stomach_ache
    > Mail: 1179998621@qq.com 
    > Created Time: 2014年02月25日 星期二 08时42分12秒
    > Propose: 
 ************************************************************************/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <linux/in.h>
#include <sys/types.h>


#define KEY ("request!")
#define MAX_SIZE 1024
#define TIME_INTERVAL 3
int
main(int argc, char **argv) 
{
int cfd;
int recbytes;
int sin_size;
char buffer[MAX_SIZE] = {''};
struct sockaddr_in s_add;
unsigned short portnum = 0x8888;

printf("Hello, welcome to client! ");


cfd = socket(AF_INET, SOCK_DGRAM, 0);
if (-1 == cfd) {
printf("socket fail! ");
return -1;
}
printf("socket ok! ");


bzero(&s_add, sizeof(struct sockaddr_in));
s_add.sin_family = AF_INET;
s_add.sin_addr.s_addr = inet_addr("127.0.0.1");
s_add.sin_port = htons(portnum);


printf("s_addr = %#x, port : %#x ", s_add.sin_addr.s_addr, s_add.sin_port);

//客户端每隔3秒发送一次请求
while (1) {
   /* sleep(TIME_INTERVAL); */


if (-1 == sendto(cfd, KEY, sizeof(KEY), 0,
(struct sockaddr*)&s_add,
sizeof(s_add))) {
printf("write fail! ");
return -1;
}
printf("write ok! ");


   /* sleep(TIME_INTERVAL); */


char revmssg[MAX_SIZE];
int len = sizeof(s_add);
if (-1 == recvfrom(cfd, revmssg, MAX_SIZE, 0,
  (struct sockaddr*)&s_add,
  &len)) {
printf("read fail! ");
return -1;
}
printf("read ok! ");
printf("revmssg is: %s ", revmssg);
sleep(TIME_INTERVAL);
}


close(cfd);


return 0;
}