一、要求
- 通過一個服務器實現最多5個客戶之間的信息羣發。
- 服務器顯示客戶的登錄與退出；
- 客戶連接後首先發送客戶名稱，之後發送羣聊信息；
- 客戶輸入bye代表退出，在線客戶能顯示其他客戶的登錄於退出。
二、提示
1. 服務器端
主線程：
定義一個全局客戶信息表ent，每個元素對應一個客戶，存儲：socket描述符、客戶名、客戶IP、客戶端口、狀態（初值爲0）。主線程循環接收客戶連接請求，在ent中查詢狀態爲0的元素，如果不存在狀態爲0的元素（即連接數超過最大連接數），向客戶發送EXIT標誌； 否則，修改客戶信息表中該元素的socket描述符、客戶IP、客戶端口號，狀態爲1（表示socket可用）；同時創建一個通信線程並將客戶索引號index傳遞給通信線程。
通信線程：
首先向客戶端發送OK標誌;循環接收客戶發來信息，若信息長度爲0，表示客戶端已關閉，向所有在線客戶發送該用戶退出；若信息爲用戶名，修改全局客戶信息表ent中index客戶的用戶名name，並顯示該用戶登錄；若信息爲退出，修改全局客戶信息表ent中index客戶狀態爲0，並顯示該用戶退出，終止線程；同時查詢全局客戶信息表ent，向狀態爲1的客戶發送接收的信息。
2. 客戶端
根據用戶從終端輸入的服務器IP地址及端口號連接到相應的服務器；連接成功後，接收服務端發來的信息，若爲EXIT，則達到最大用戶量，退出；若爲OK，可以通訊，首先先發送客戶名稱；主進程循環從終端輸入信息，並將信息發送給服務器；當發送給服務器爲bye後，程序退出。同時創建一個線程負責接收服務器發來的信息，並顯示，當接收的長度小於等於0時終止線程；
三、程序
客戶端與服務端的頭文件：
ifndef _GCS_H
#define _GCS_H
#include <netinet/in.h>
#define MSGLEN 1024
#define OK 1
#define EXIT 2
#define MSG 3
#define USER 4
struct CLIENTMSG {
int op;
char user[20];
char buf[MSGLEN];
};
struct CLIENTS {
int sockfd;
int port;
char user[20];
struct sockaddr_in client;
int stat;
};
struct CLIENTS ent[5];
#endif
服務端：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ipc.h>
#include <pthread.h>
#include "group_chat_system.h"
extern struct CLIENTS ent[5];
void* func(void *arg);
void sever_process(int index);
int main(int argc, char **argv)
{
int sever_fd,client_fd;
struct sockaddr_in sever,client;
char ip[20];
int port,clientlen;
unsigned char i,index;
struct CLIENTMSG clientMSG;
pthread_t tid;
int *arg;
for(i=0; i<5; i++) {
ent[i].stat = 0;
}
/***************創建服務器sockfd************/
if((sever_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket error");
exit(errno);
}
/***************輸入ip與端口*****************/
printf("please input ip:");
scanf("%s", ip);
printf("\nplease input port:");
scanf("%d", &port);
printf("\n");
/******************bind***********************/
bzero(&sever, sizeof(sever));
sever.sin_family = AF_INET;
sever.sin_port = htons(port);
sever.sin_addr.s_addr= inet_addr(ip);
if(bind(sever_fd, (struct sockaddr*)&sever, sizeof(struct sockaddr)) == -1) {
perror("bind error");
exit(errno);
}
/******************listen***********************/
if(listen(sever_fd, 5) == -1) {
perror("listen error");
exit(errno);
}
while(1) {
clientlen = sizeof(client);
if((client_fd = accept(sever_fd, (struct sockaddr*)&client, &clientlen)) == -1) {
perror("accept error");
exit(errno);
}
printf("accept ok\n");
index = 5;
for(i=0; i<5; i++) {
if(ent[i].stat ==0){
index = i;
break;
}
}
if(index <= 4) {
printf("client_fd : %d\n", client_fd);
ent[index].sockfd = client_fd;
ent[index].port = port;
ent[index].client = client;
ent[index].stat = 1;
arg = malloc(sizeof(int));
*arg = index;
pthread_create(&tid, NULL, func, (void*)arg);
} else {
printf("the client already has 5\n");
bzero(&clientMSG, sizeof(clientMSG));
clientMSG.op = EXIT;
send(client_fd, &clientMSG, sizeof(clientMSG), 0);
close(client_fd);
}
}
close(sever_fd);
return 0;
}
void *func(void *arg)
{
int *info;
info = (int *)arg;
sever_process(*info);
pthread_exit(NULL);
}
void sever_process(int index)
{
struct CLIENTMSG sendMSG;
struct CLIENTMSG recvMSG;
int len,i;
/*首先發送邋OK標誌*/
sendMSG.op = OK;
send(ent[index].sockfd, &sendMSG, sizeof(sendMSG), 0);
while(1) {
bzero(&sendMSG, sizeof(sendMSG));
bzero(&recvMSG, sizeof(recvMSG));
len = recv(ent[index].sockfd, &recvMSG, sizeof(recvMSG), 0);
if(len == 0) {
sendMSG.op = EXIT;
for(i=0; i<5; i++) {
if(ent[i].stat == 1)
send(ent[i].sockfd, &sendMSG, sizeof(sendMSG), 0);
}
}
if(len > 0) {
if(recvMSG.op == USER) {
bcopy(recvMSG.user, ent[index].user, strlen(recvMSG.user));
printf("user %s login form ip: %s port: %d\n", ent[index].user, inet_ntoa(ent[index].client.sin_addr), ntohs(ent[index].client.sin_port));
sendMSG.op = USER;
}
if(recvMSG.op == EXIT) {
//printf("recv exit\n");
sendMSG.op = EXIT;
bcopy(ent[index].user, sendMSG.user, strlen(recvMSG.user));
for(i=0; i<5; i++) {
if(ent[i].stat == 1)
send(ent[i].sockfd, &sendMSG, sizeof(sendMSG), 0);
}
break;
}
if(recvMSG.op == MSG) {
//printf("recv msg\n");
//printf("%s: %s", recvMSG.user,recvMSG.buf);
sendMSG.op= MSG;
}
bcopy(recvMSG.user, sendMSG.user, strlen(recvMSG.user));
bcopy(recvMSG.buf, sendMSG.buf, strlen(recvMSG.buf));
for(i=0; i<5; i++) {
//printf("\n%d: %s\n", sendMSG.op, sendMSG.user);
if(ent[i].stat == 1) {
if(strncmp(ent[i].user, sendMSG.user, strlen(sendMSG.user)))
send(ent[i].sockfd, &sendMSG, sizeof(sendMSG), 0);
}
}
}
}
}
客戶端：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ipc.h>
#include <pthread.h>
#include "group_chat_system.h"
struct client_arg {
int sockfd;
struct CLIENTMSG clientMSG;
};
struct client_arg *arg;
void *func(void* arg);
void client_process(int sockfd, struct CLIENTMSG clientMSG);
int main(int argc, char **argv)
{
int sockfd;
struct sockaddr_in sever;
char ip[20];
unsigned int port,len;
struct CLIENTMSG sendMSG;
pthread_t tid;
if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket error");
exit(1);
}
printf("please input ip:");
scanf("%s", ip);
printf("\nplease input port:");
scanf("%d", &port);
printf("\n");
bzero(&sever, sizeof(sever));
sever.sin_family = AF_INET;
sever.sin_port = htons(port);
inet_aton(ip, &sever.sin_addr);
if(connect(sockfd, (struct sockaddr*)&sever, sizeof(struct sockaddr)) == -1) {
perror("connect error");
exit(errno);
}
len = recv(sockfd, &sendMSG, sizeof(sendMSG), 0);
if(len > 0){
if(sendMSG.op == EXIT) {
printf("exceed the numble of users\n");
}
if(sendMSG.op == OK) {
bzero(&sendMSG, sizeof(sendMSG));
printf("please input client name: ");
fgets(sendMSG.user, MSGLEN, stdin);
//scanf("%s", sendMSG.user);
sendMSG.op = USER;
send(sockfd, &sendMSG, sizeof(sendMSG), 0);
arg = (struct client_arg*)malloc(sizeof(struct client_arg));
arg->sockfd = sockfd;
pthread_create(&tid, NULL, func, (void*)arg);
while(1) {
// bzero(&sendMSG, sizeof(sendMSG));
sendMSG.op = MSG;
//printf("waiting...");
fgets(sendMSG.buf, MSGLEN, stdin);
//scanf("%s", sendMSG.buf);
//printf("%s: %s %d\n", sendMSG.user,sendMSG.buf, sendMSG.op);
if(!strncasecmp(sendMSG.buf, "bye", 3)) {
sendMSG.op = EXIT;
send(sockfd, &sendMSG, sizeof(sendMSG), 0);
break;
}
send(sockfd, &sendMSG, sizeof(sendMSG), 0);
}
}
pthread_cancel(tid);
}
close(sockfd);
return 0;
}
void *func(void* arg)
{
struct client_arg *info;
info = (struct client_arg*)arg;
client_process(info->sockfd, info->clientMSG);
free(arg);
pthread_exit(NULL);
}
void client_process(int sockfd, struct CLIENTMSG clientMSG)
{
int len;
while(1) {
bzero(&clientMSG, sizeof(clientMSG));
len = recv(sockfd, &clientMSG, sizeof(clientMSG), 0);
if(len > 0) {
if(clientMSG.op==USER){
printf("the user %s is login.\n",clientMSG.user);
}else if(clientMSG.op == EXIT){
printf("the user %s is logout.\n",clientMSG.user);
}else if(clientMSG.op == MSG){
printf("%s: %s\n",clientMSG.user,clientMSG.buf);
}
}
}
}
makefile:
main:sever.o client.o
gcc sever.o -o sever -lpthread
gcc client.o -o client -lpthread
sever.o:sever.c
gcc -c sever.c group_chat_system.h
gcc -c client.c group_chat_system.h
clean:
rm *.o sever client
四、測試
運行服務端：
運行客戶端：（3個）
測試成功。
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