UDP通信、本地套接字

#include <sys/types.h>
#include <sys/socket >
ssize_t sendto(int sockfd, const void *buf, size_t len, int flags,const struct sockaddr *dest_addr, socklen_t addrlen);- 参数：- sockfd : 通信的fd- buf : 要发送的数据- len : 发送数据的长度- flags : 0- dest_addr : 通信的另外一端的地址信息- addrlen : 地址的内存大小ssize_t recvfrom(int sockfd, void *buf, size_t len, int flags,struct sockaddr *src_addr, socklen_t *addrlen);- 参数：- sockfd : 通信的fd- buf : 接收数据的数组- len : 数组的大小- flags : 0- src_addr : 用来保存另外一端的地址信息，不需要可以指定为NULL- addrlen : 地址的内存大小

udp_server.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>int main() {// 1.创建一个通信的socketint fd = socket(PF_INET,SOCK_DGRAM,0);if(fd == -1) {perror("socket");exit(-1);}// 2.绑定struct sockaddr_in saddr;saddr.sin_family = AF_INET;saddr.sin_port = htons(9999);saddr.sin_addr.s_addr = INADDR_ANY;int ret = bind(fd,(struct sockaddr*)&saddr,sizeof(saddr));if(ret == -1) {perror("bind");exit(-1);}// 3.通信 while (1) {char recvbuf[128] = {0};char ipbuf[16] = {0};struct sockaddr_in caddr;int len = sizeof(caddr);// 接收数据int num = recvfrom(fd,recvbuf,sizeof(recvbuf),0,(struct sockaddr*)&caddr,&len);if(num == -1) {perror("recvfrom");exit(-1);}inet_ntop(AF_INET,(struct sockaddr*)&caddr.sin_addr.s_addr,ipbuf,sizeof(ipbuf));printf("Client IP : %s,Port : %d\n",ipbuf,ntohs(caddr.sin_port));printf("client say : %s\n",recvbuf);// 发送数据sendto(fd,recvbuf,strlen(recvbuf) + 1,0,(struct sockaddr*)&caddr,sizeof(caddr));}close(fd);return 0;
}

udp_client.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>int main() {// 1.创建一个通信的socketint fd = socket(PF_INET,SOCK_DGRAM,0);if(fd == -1) {perror("socket");exit(-1);}// 服务器的地址信息struct sockaddr_in saddr;saddr.sin_family = AF_INET;saddr.sin_port = htons(9999);inet_pton(AF_INET,"127.0.0.1",&saddr.sin_addr.s_addr);int num = 0;// 3.通信 while (1) {// 发送数据char sendBuf[128] = {0};sprintf(sendBuf,"hello,i am client %d \n",num++);sendto(fd,sendBuf,strlen(sendBuf) + 1,0,(struct sockaddr*)&saddr,sizeof(saddr));// 接收数据int num = recvfrom(fd,sendBuf,sizeof(sendBuf),0,NULL,NULL);printf("server say : %s\n",sendBuf);sleep(1);}close(fd);return 0;
}

heheda@heheda:~/Linux/lesson37$ gcc udp_server.c -o server
heheda@heheda:~/Linux/lesson37$ ./server
Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 0 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 1 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 2 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 3 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 4 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 0 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 5 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 1 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 6 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 2 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 7 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 3 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 8 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 4 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 9 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 5 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 10 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 6 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 11 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 7 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 12 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 8 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 13 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 9 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 14 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 10 Client IP : 127.0.0.1,Port : 34127
client say : hello,i am client 15 Client IP : 127.0.0.1,Port : 53230
client say : hello,i am client 11