select实现多路复用(BSD SOCKET)

/*server.cpp*/

#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <errno.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#define MYPORT 2000 // the port users will be connecting to#define BACKLOG 5 // how many pending connections queue will hold#define BUF_SIZE 200typedef struct sockaddr_in my_sockaddr_in;typedef struct _cust_{ int fd; // accepted connection fd my_sockaddr_in* client_addr;}custConn;custConn fd_A[BACKLOG];void distribution(int id, char * mess){ int i; for (i = 0; i < BACKLOG; i++) { if(i != id && fd_A[i].fd > 0) { send(fd_A[i].fd, mess, strlen(mess) + 1, 0); } }}int main(void) {int sock_fd, new_fd; // listen on sock_fd, new connection on new_fdmy_sockaddr_in server_addr; // server address informationmy_sockaddr_in* pClient_addr; // connector's address informationsocklen_t sin_size;int yes = 1;char buf[BUF_SIZE];char content[BUF_SIZE + 100];int ret;if ((sock_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {perror("socket");exit(1);}if (setsockopt(sock_fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {perror("setsockopt");exit(1);}server_addr.sin_family = AF_INET; // host byte orderserver_addr.sin_port = htons(MYPORT); // short, network byte orderserver_addr.sin_addr.s_addr = INADDR_ANY; // automatically fill with my IPmemset(server_addr.sin_zero, '/0', sizeof(server_addr.sin_zero));if (bind(sock_fd, (struct sockaddr *) &server_addr, sizeof(server_addr)) == -1) {perror("bind");exit(1);}if (listen(sock_fd, BACKLOG) == -1) {perror("listen");exit(1);}printf("listen port %d/n", MYPORT);fd_set fdsr;int maxsock; int i;struct timeval tv;sin_size = sizeof(my_sockaddr_in);maxsock = sock_fd;while (1){// initialize file descriptor setFD_ZERO(&fdsr);FD_SET(sock_fd, &fdsr);// timeout settingtv.tv_sec = 1;tv.tv_usec = 0;// add active connection to fd setfor (i = 0; i < BACKLOG; i++) {if (fd_A[i].fd != 0) {FD_SET(fd_A[i].fd, &fdsr);}}ret = select(maxsock + 1, &fdsr, NULL, NULL, &tv);if (ret < 0){perror("select");break;}else if (ret == 0){ //timeoutcontinue;}// check every fd in the setfor (i = 0; i < BACKLOG; i++){if (fd_A[i].fd > 0 && FD_ISSET(fd_A[i].fd, &fdsr)){ memset(buf, 0x00, BUF_SIZE);ret = recv(fd_A[i].fd, buf, sizeof(buf), 0);if (ret <= 0){ //client closeprintf("client[%d] offline/n", i);close(fd_A[i].fd); //notice other user memset(content, 0x00, BUF_SIZE); sprintf(content, "%s offline", inet_ntoa((fd_A[i].client_addr)->sin_addr)); distribution(i, content); //clear fd_setFD_CLR(fd_A[i].fd, &fdsr);fd_A[i].fd = 0;}else{ // receive data printf("client[%d] send:%s/n", i, buf); memset(content, 0x00, BUF_SIZE + 100);sprintf(content, "%s say: %s", inet_ntoa((fd_A[i].client_addr)->sin_addr), buf);distribution(i, content);}}}// check whether a new connection comesif (FD_ISSET(sock_fd, &fdsr)){ pClient_addr = new my_sockaddr_in;new_fd = accept(sock_fd, (struct sockaddr *) pClient_addr, &sin_size);if (new_fd <= 0) {perror("accept");continue;} printf("new connection %s:%d socket:%d ", inet_ntoa(pClient_addr->sin_addr), ntohs( pClient_addr->sin_port), new_fd);//new connection int id; for(id = 0; id < BACKLOG; id++) { //find idle id if(fd_A[id].fd == 0) break; } printf("id: %d/n", id);if (id == BACKLOG){printf("but, max connections arrive, reject./n");send(new_fd, "bye", 4, 0);close(new_fd);continue;}//new user fd_A[id].fd = new_fd;/*save new socket*/ fd_A[id].client_addr = pClient_addr; if (new_fd > maxsock)//select need max maxsock = new_fd; //welcome this user send(new_fd, "welcome!", 9, 0); //notice other user memset(content, 0x00, BUF_SIZE + 100); sprintf(content, "%s online", inet_ntoa(pClient_addr->sin_addr)); distribution(id, content);}}//end while// close other connectionsfor (i = 0; i < BACKLOG; i++) {if (fd_A[i].fd != 0) {close(fd_A[i].fd);delete fd_A[i].client_addr;}}exit(0);}

 

/*client.cpp*/

 

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <netdb.h>#define PORT 2000#define MAXSIZE 100int main(int argc, char * argv[]) { if (argc != 2) { printf("error./n"); exit(1); } int listenfd, num; struct hostent * he; struct sockaddr_in server; if ((he = gethostbyname(argv[1])) == NULL) { perror("gethostbyname"); exit(1); } if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) { perror("socket"); exit(1); } memset(&server, 0x00, sizeof(server)); server.sin_family = AF_INET; server.sin_port = htons(PORT); server.sin_addr = *((struct in_addr *) he->h_addr); if (connect(listenfd, (struct sockaddr *) &server, sizeof(server)) == -1) { perror("connect"); exit(1); } char buf[MAXSIZE]; int length; fd_set fdsr; int maxsock, ret; struct timeval tv; maxsock = listenfd; while(true) { // initialize file descriptor set FD_ZERO(&fdsr); FD_SET(0, &fdsr); FD_SET(listenfd, &fdsr); // timeout setting tv.tv_sec = 1; tv.tv_usec = 0; ret = select(maxsock + 1, &fdsr, NULL, NULL, &tv); if (ret < 0) { perror("select"); break; } else if (ret == 0) { continue; } //check socket read if (FD_ISSET(listenfd, &fdsr)) { memset(buf, 0x00, sizeof(buf)); length = recv(listenfd, buf, MAXSIZE, 0); if (length > 0) { printf("-> %s/n", buf); memset(buf, 0x00, sizeof(buf)); } } //check input if (FD_ISSET(0, &fdsr) && getchar() != EOF) { scanf("%s", buf); if(strcmp(buf, "exit") == 0) break; if ((length = send(listenfd, buf, sizeof(buf), 0)) == -1) { perror("send data:"); //close(socketfd); return -1; } } } close(listenfd); return 0;}