UDP简介
UDP与TCP相比，UDP是没有链接的协议，可以把他比作电子邮件，收信方不需要确认就可以接收邮件（不需要握手），这一点以TCP协议不同。下面简单介绍GitHub上的开源项目TCP-Socket
结果是这样的
$ ./server &$ ./client 127.0.0.1this is a testthis is a test
服务器端代码server.c
#include <stdio.h>#include <stdlib.h>#include <sys/socket.h>#include <string.h>#include <sys/types.h>#include <netinet/ip.h>const int SERV_PORT = 6000;const int MAXLINE = 2048;void dg_echo(int sockfd , struct sockaddr *pcliaddr , socklen_t clilen){int n;socklen_t len;char mesg[MAXLINE];for( ; ;){len = clilen;if((n = recvfrom(sockfd , mesg , MAXLINE , 0 , pcliaddr , &len)) <0){perror("recvfrom error");exit(1);}//ifif((n = sendto(sockfd , mesg , n , 0 , pcliaddr , len)) < 0){perror("sendto error");exit(1);}//if}//for}int main(int argc , char **argv){int sockfd;struct sockaddr_in servaddr , cliaddr;bzero(&servaddr , sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_addr.s_addr = htonl(INADDR_ANY);servaddr.sin_port = htons(SERV_PORT);if((sockfd = socket(AF_INET , SOCK_DGRAM , 0)) < 0){perror("socket error");exit(1);}//ifif(bind(sockfd , (struct sockaddr *)&servaddr , sizeof(servaddr))){perror("bind error");exit(1);}//ifdg_echo(sockfd , (struct sockaddr *)&cliaddr , sizeof(cliaddr));}
客户端代码client.c
#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/socket.h>#include <netinet/in.h>const int SERV_PORT = 6000;const int MAXLINE = 2048;void dg_cli(FILE *fp , int sockfd , const struct sockaddr *pservaddr , socklen_t servlen){int n;char sendline[MAXLINE] , recvline[MAXLINE+1];while(fgets(sendline , MAXLINE , fp) != NULL){if(sendto(sockfd , sendline , strlen(sendline) , 0 , pservaddr , servlen) < 0){perror("sendto error");exit(1);}//ifif( ( n = recvfrom(sockfd , recvline , MAXLINE , 0 , NULL , NULL)) < 0){perror("recvfrom error");exit(1);}//ifrecvline[n] = '\0';fputs(recvline , stdout);}//while}int main(int argc , char **argv){int sockfd , t;struct sockaddr_in servaddr;if(argc != 2){perror("usage: udpcli <IPaddress>");exit(1);}//ifbzero(&servaddr , sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_port = htons(SERV_PORT);if((t = inet_pton(AF_INET , argv[1], &servaddr.sin_addr)) <= 0){perror("inet_pton error");exit(1);}//ifif((sockfd = socket(AF_INET , SOCK_DGRAM , 0)) < 0){perror("socket error");exit(1);}//ifdg_cli(stdin , sockfd , (struct sockaddr *)&servaddr , sizeof(servaddr)) ;exit(0);}
Makefile
ALL:gcc server.c -o server -lmgcc client.c -o client -lm
代码来自GitHub帐号，此为学习笔记，源代码请查看GitHub
