使用AF_INET实现UDP点对点通信示例
此示例程序实现AF_INET实现UDP点对点通信示例，即采用AF_INET协议，数据传送方式为UDP数据报方式，主要功能是发送方向接收方发送一条简单的消息“hello world!”.
服务器端要先运行，然后运行客户端程序
客户端程序代码：
#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <errno.h>#include <arpa/inet.h>int main(int argc,char *argv[]){struct sockaddr_in s_addr;int sock;int addr_len;int len;char buff[128];if((sock=socket(AF_INET,SOCK_DGRAM,0))==-1){perror("socket");exit(1);}elseprintf("sock init done\n");s_addr.sin_family = AF_INET;s_addr.sin_port = htons(7838);if(argv[1])s_addr.sin_addr.s_addr = inet_addr(argv[1]);else{printf("input server ip\n");exit(0);}addr_len = sizeof(s_addr);strcpy(buff,"hello,world");len=sendto(sock,buff,strlen(buff),0,(struct sockaddr *)&s_addr,addr_len);if(len<0){perror("sendto");exit(1);}printf("send sucess");return 0;}
服务器端程序代码：
#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <errno.h>#include <arpa/inet.h>int main(){struct sockaddr_in s_addr;struct sockaddr_in c_addr;int sock;socklen_t addr_len;int len;char buff[128];if((sock=socket(AF_INET,SOCK_DGRAM,0))==-1){perror("socket");exit(1);}elseprintf("create socket\n");memset(&s_addr,0,sizeof(s_addr));s_addr.sin_family = AF_INET;s_addr.sin_port = htons(7838);s_addr.sin_addr.s_addr=INADDR_ANY;if(bind(sock,(struct sockaddr *)&s_addr,sizeof(s_addr))==-1){perror("bind");exit(1);}elseprintf("bind address to sock.\n\r");addr_len=sizeof(c_addr);while(1){len = recvfrom(sock,buff,sizeof(buff)-1,0,(struct sockaddr *)&c_addr,&addr_len);if(len<0){perror("recvfrom");exit(1);}buff[len]='\0';printf("receive come from %s:%d message:%s\n\r",inet_ntoa(c_addr.sin_addr),ntohs(c_addr.sin_port),buff);}return 0;}