Linux下select函数实现的聊天服务器

Linux下select函数实现的聊天服务器 佟强 http://blog.youkuaiyun.com/microtong

Windows下的图形客户端：

基于WSAAsyncSelect模型实现的聊天室图形客户端

http://blog.youkuaiyun.com/microtong/archive/2009/12/12/4990175.aspx

Window下的命令行客户端：

http://blog.youkuaiyun.com/microtong/archive/2009/12/12/4990138.aspx

消息缓冲区类MessageBuffer，接收线程将受到的消息放入缓冲区，发送线程从缓冲区中取出消息

MessageBuffer.h

//MessageBuffer.h #ifndef _MESSAGE_BUF_INCLUDE_ #define _MESSAGE_BUF_INCLUDE_ #include <pthread.h> #define MESSAGE_COUNT 16 #define MESSAGE_LENGTH 2048 class MessageBuffer{ private: pthread_mutex_t mutex;//访问缓冲的互斥量 pthread_cond_t condition;//访问缓冲区的条件变量 //消息缓冲区，循环队列 char buf[MESSAGE_COUNT][MESSAGE_LENGTH]; int rear; //循环队列的队尾 int front; //循环队列的队首 public: bool toStop; //构造函数 MessageBuffer(); //析构函数 virtual ~MessageBuffer(); //将消息放入消息缓冲区，当缓冲区满时阻塞，toStop=true时返回-1 int PutMessage(const char *message); //从消息缓冲区中获得消息，当缓冲区空时阻塞，toStop=true时返回-1 int GetMessage(char *mbuf, int buflen); }; #endif

MessageBuffer.cpp

//MessageBuffer.cpp #include <stdio.h> #include <string.h> #include <time.h> #include <pthread.h> #include "MessageBuffer.h" MessageBuffer::MessageBuffer() { toStop = false; pthread_mutex_init(&mutex,NULL);//初始化互斥量 pthread_cond_init(&condition,NULL);//初始化条件变量 rear = 0; //队尾指针指向0 front = 0; //队首指针指向0 printf("A MessageBuffer intance created.\n"); } MessageBuffer::~MessageBuffer(){ pthread_mutex_destroy(&mutex); pthread_cond_destroy(&condition); printf("A MessageBuffer instance destroyed.\n"); } //将消息放入消息缓冲区 int MessageBuffer::PutMessage(const char *message){ struct timespec t; //等待互斥量 pthread_mutex_lock(&mutex); while(!toStop && (rear+1)%MESSAGE_COUNT==front){ t.tv_sec = time(NULL)+1; t.tv_nsec = 0; pthread_cond_timedwait(&condition,&mutex,&t); } if(toStop){ pthread_cond_broadcast(&condition); pthread_mutex_unlock(&mutex); return -1; } int messageLen = strlen(message); int copyLen = messageLen>=MESSAGE_LENGTH?MESSAGE_LENGTH-1:messageLen; memcpy(buf[rear],message,copyLen); buf[rear][copyLen]='\0'; rear = (rear+1)%MESSAGE_COUNT; pthread_cond_signal(&condition); pthread_mutex_unlock(&mutex); return 0; } //从消息缓冲区中获得消息 int MessageBuffer::GetMessage(char *mbuf, int buflen){ struct timespec t; pthread_mutex_lock(&mutex); while(!toStop && rear==front){ t.tv_sec = time(NULL)+1; t.tv_nsec = 0; pthread_cond_timedwait(&condition,&mutex,&t); } if(toStop){ pthread_cond_broadcast(&condition); pthread_mutex_unlock(&mutex); return -1; } int messageLen = strlen(buf[front]); int copyLen = messageLen>=buflen ? buflen-1 : messageLen; memcpy(mbuf,buf[front],copyLen); mbuf[copyLen]='\0'; front = (front+1)%MESSAGE_COUNT; pthread_cond_signal(&condition); pthread_mutex_unlock(&mutex); return 0; }

客户类Clients，用于维护套接字socket和套接字地址struct sockaddr_in之间的对应关系，并维护用户的姓名。

Clients.h

//Clients.h #ifndef _CLIENTS_INCLUDE_ #define _CLIENTS_INCLUDE_ #include <sys/types.h> #include <netinet/in.h> #include <pthread.h> #define NAME_LEN 50 #define MAX_CLIENT 30 typedef struct client_info{ int sock; struct sockaddr_in clientAddr; char name[NAME_LEN]; }CLIENT_INFO; class Clients{ private: pthread_mutex_t mutex; CLIENT_INFO client[MAX_CLIENT]; int clientCount; int IPtoString(unsigned long ip, char *buf, int buflen); int Search(int sock); public: Clients();//构造函数 virtual ~Clients();//析构函数 int GetClientCount(); bool PutClient(int sock,const struct sockaddr_in &clientAddr); void RemoveClient(int sock); bool GetAddrBySocket(int sock,struct sockaddr_in *addr); bool PutName(int sock,const char *name, int namelen); bool GetName(int sock, char *name, int namelen); int GetAllSocket(int* sockArray, int arrayLen ); }; #endif

Clients.cpp

//Clients.cpp #include <stdio.h> #include <string.h> #include <arpa/inet.h> #include "Clients.h" Clients::Clients() { pthread_mutex_init(&mutex, NULL); clientCount = 0; printf("Clients created.\n"); } Clients::~Clients() { pthread_mutex_destroy(&mutex); printf("Clients destroyed.\n"); } int Clients::Search(int sock){ int index = -1; for(int i=0; i<clientCount; i++) { if(client[i].sock==sock){ index = i; break; } } return index; } int Clients::IPtoString(unsigned long ip,char *buf,int buflen){ unsigned char *p = (unsigned char*)&ip; if(buflen<16){ return -1; } sprintf(buf,"%u.%u.%u.%u",*p,*(p+1),*(p+2),*(p+3)); return strlen(buf); } int Clients::GetClientCount(){ return clientCount; } bool Clients::PutClient(int sock,const struct sockaddr_in &clientAddr) { if(clientCount==MAX_CLIENT){ return false; } pthread_mutex_lock(&mutex); client[clientCount].sock = sock; client[clientCount].clientAddr = clientAddr; int buflen = sizeof(client[clientCount].name); int pos = IPtoString(clientAddr.sin_addr.s_addr,client[clientCount].name,buflen); sprintf(&client[clientCount].name[pos],":%d",ntohs(clientAddr.sin_port)); clientCount++; pthread_mutex_unlock(&mutex); return true; } void Clients::RemoveClient(int sock){ pthread_mutex_lock(&mutex); int index = Search(sock); if(index!=-1){ for(int i=index; i<clientCount-1; i++){ client[i] = client[i+1]; } clientCount--; } pthread_mutex_unlock(&mutex); } bool Clients::GetAddrBySocket(int sock,struct sockaddr_in *addr){ pthread_mutex_lock(&mutex); int index = Search(sock); if(index!=-1){ memcpy(addr,&client[index].clientAddr,sizeof(struct sockaddr_in)); } pthread_mutex_unlock(&mutex); return index!=-1; } bool Clients::PutName(int sock,const char *name,int namelen) { pthread_mutex_lock(&mutex); int index = Search(sock); if(index!=-1){ int copyLen = namelen>=NAME_LEN ? NAME_LEN-1:namelen; memcpy(client[index].name,name,copyLen); client[index].name[copyLen]='\0'; } pthread_mutex_unlock(&mutex); return index!=-1; } bool Clients::GetName(int sock, char *name, int namelen) { pthread_mutex_lock(&mutex); int index = Search(sock); if(index!=-1){ int msgLen = strlen(client[index].name); int copyLen = (msgLen<namelen)? msgLen:(namelen-1); memcpy(name,client[index].name,copyLen); name[copyLen]='\0'; } pthread_mutex_unlock(&mutex); return index!=-1; } int Clients::GetAllSocket(int* sockArray, int arrayLen ) { pthread_mutex_lock(&mutex); int copyCount = arrayLen>clientCount ? clientCount : arrayLen; for(int i=0; i<copyCount; i++){ sockArray[i] = client[i].sock; } pthread_mutex_unlock(&mutex); return copyCount; }

聊天室服务器主程序Server.cpp

/*server.c*/ #include <stdio.h> #include <string.h> #include <stdlib.h> #include <sys/types.h> #include <netinet/in.h> #include <sys/socket.h> #include <sys/select.h> #include <pthread.h> #include <unistd.h> #include <netdb.h> #include <arpa/inet.h> #include "MessageBuffer.h" #include "Clients.h" using namespace std; #define SERVER_PORT 8000 #define BUFFER_SIZE 4096 #ifndef MAX_CLIENT #define MAX_CLIENT 30 #endif #ifndef NAME_LEN #define NAME_LEN 50 #endif MessageBuffer messageBuffer; Clients clients; void* ListenThread(void*); void* RecvThread(void*); void* SendThread(void*); void ProcessMessage(int sock,char buf[],int bufsize,int bytes); bool toStop=false; int main(int argc,char* argv[]) { if(argc!=2){ printf("Usage: %s PortNumber\n",argv[0]); return -1; } unsigned short port; if((port = atoi(argv[1]))==0){ printf("incorrect port number.\n"); return -1; } int s; struct sockaddr_in serverAddr; s = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); if(s==-1){ fprintf(stderr,"create socket failed.\n"); return -1; } bzero(&serverAddr,sizeof(struct sockaddr_in)); serverAddr.sin_family = AF_INET; serverAddr.sin_port = htons(port); serverAddr.sin_addr.s_addr = htonl(INADDR_ANY); if(bind(s,(struct sockaddr*)&serverAddr,sizeof(serverAddr))==-1){ fprintf(stderr,"bind socket to port %d failed.\n",port); return -1; } if(listen(s,SOMAXCONN)==-1){ fprintf(stderr,"listen failed.\n"); return -1; } printf("Server is listening on "); char hostname[255]; if(gethostname(hostname,sizeof(hostname))){ printf("gethostname() failed.\n"); return -1; } struct hostent* pHost = gethostbyname(hostname); if(pHost){ for(int i=0; pHost->h_addr_list[i]; i++){ printf("%s ",inet_ntoa(*(in_addr*)pHost->h_addr_list[i])); } } printf("\nport: %d\n",port); pthread_t tListenId; if(pthread_create(&tListenId,NULL,ListenThread,&s)){ printf("failed to create listen thread.\n"); return -1; } pthread_t tRecvId; if(pthread_create(&tRecvId,NULL,RecvThread,NULL)){ printf("failed to create recv thread.\n"); return -1; } pthread_t tSendId; if(pthread_create(&tSendId,NULL,SendThread,NULL)){ printf("failed to create send thread.\n"); return -1; } while(getchar()!='q'); toStop = true; messageBuffer.toStop = true; pthread_join(tListenId,NULL); pthread_join(tRecvId,NULL); pthread_join(tSendId,NULL); close(s); int sock[MAX_CLIENT]; int count = clients.GetAllSocket(sock,MAX_CLIENT); for(int i=0;i<count;i++){ close(sock[i]); } printf("server stopped.\n"); return 0; } void* ListenThread(void*ps){ int s=*(int*)ps; fd_set listenSet; int sock; struct sockaddr_in clientAddr; struct timeval timeout; while(!toStop){ FD_ZERO(&listenSet); FD_SET(s,&listenSet); timeout.tv_sec = 5; timeout.tv_usec = 0; int ret = select(s+1,&listenSet,NULL,NULL,&timeout); if(toStop){ printf("ListenThread: exit.\n"); return NULL; } if(ret==-1){ printf("ListenThread: select() failed!\n"); }else if(ret==0){ printf("ListenThread: select() time out.\n"); }else{ if(FD_ISSET(s,&listenSet)){ socklen_t addrlen = sizeof(struct sockaddr_in); memset(&clientAddr,0,sizeof(struct sockaddr_in)); if((sock=accept(s,(struct sockaddr*)&clientAddr,&addrlen))==-1){ fprintf(stderr,"accept failed.\n"); } if(!clients.PutClient(sock,clientAddr)){ printf("max client limited. MAX_CLIENT=%d\n",MAX_CLIENT); close(sock); } printf("accept a connection from %s:%u\n", inet_ntoa(*(struct in_addr*)&(clientAddr.sin_addr.s_addr)), ntohs(clientAddr.sin_port)); printf("new socket is: %u\n",sock); } } } return NULL; } void* RecvThread(void*){ fd_set readSet; int sock[MAX_CLIENT]; char buf[BUFFER_SIZE]; struct timeval timeout; while(!toStop){ int count = clients.GetAllSocket(sock,MAX_CLIENT); if(count==0){ sleep(2); if(toStop){ printf("RecvThread: exit.\n"); return NULL; } continue; } FD_ZERO(&readSet); int maxfd=0; for(int i=0;i<count;i++){ printf("--%d",sock[i]); FD_SET(sock[i],&readSet); if(sock[i]>maxfd){ maxfd = sock[i]; } } printf("\n"); timeout.tv_sec = 2; timeout.tv_usec = 0; int ret = select(maxfd+1,&readSet,NULL,NULL,&timeout); if(toStop){ printf("RecvThread: exit.\n"); return NULL; } if(ret==-1){ printf("RecvThread: select() failed!\n"); }else if(ret==0){ printf("RecvThread: select() time out.\n"); }else{ for(int i=0; i<count; i++){ if(FD_ISSET(sock[i],&readSet)){ int bytes=recv(sock[i],buf,sizeof(buf)-1,0); if(bytes==-1){ printf("RecvThread: recv failed.\n"); clients.RemoveClient(sock[i]); close(sock[i]); }else if(bytes==0){ printf("RecvThread: socket closed by the other side.\n"); clients.RemoveClient(sock[i]); close(sock[i]); }else{ ProcessMessage(sock[i],buf,sizeof(buf),bytes); } } } } } return NULL; } void* SendThread(void*){ fd_set writeSet; int sock[MAX_CLIENT]; char buf[BUFFER_SIZE]; struct timeval timeout; while(!toStop){ int ret = messageBuffer.GetMessage(buf,sizeof(buf)); printf("get a message from buffer.\n"); if(ret==-1){ printf("SendThread: exit.\n"); return NULL; } int count = clients.GetAllSocket(sock,MAX_CLIENT); FD_ZERO(&writeSet); int maxfd = 0; for(int i=0;i<count;i++){ FD_SET(sock[i],&writeSet); if(sock[i]>maxfd){ maxfd = sock[i]; } } timeout.tv_sec = 2; timeout.tv_usec = 0; ret = select(maxfd+1,NULL,&writeSet,NULL,&timeout); if(toStop){ printf("SendThread: exit.\n"); return NULL; } if(ret==-1){ printf("SendThread: select() failed!\n"); }else if(ret==0){ printf("SendThread: select() time out.\n"); }else{ for(int i=0;i<count;i++){ if(FD_ISSET(sock[i],&writeSet)){ int messageLen = strlen(buf); int bytes = send(sock[i],buf,messageLen,0); if(bytes==-1){ printf("SendThread: send() failed.\n"); }else if(bytes!=messageLen){ printf("SendThread: send message trunked."); }else{ //do nothing } } } } } return NULL; } void ProcessMessage(int sock,char buf[],int bufsize,int bytes){ struct sockaddr_in clientAddr; if(!clients.GetAddrBySocket(sock,&clientAddr)){ printf("ProcessMessage: can not find socket address.\n"); return; } char ipString[16]; unsigned char *ip = (unsigned char*)&clientAddr.sin_addr.s_addr; sprintf(ipString,"%u.%u.%u.%u",*ip,*(ip+1),*(ip+2),*(ip+3)); unsigned short port = ntohs(clientAddr.sin_port); buf[bytes]='\0'; printf("Message from %s:%d: %s\n",ipString,port,buf); const char* CMD_BYE="bye"; if(strcmp(buf,CMD_BYE)==0){ send(sock,CMD_BYE,strlen(CMD_BYE),0); clients.RemoveClient(sock); close(sock); printf("%s:%u disconnected.\n", ipString, port); return; }else{ char bufWithName[BUFFER_SIZE+NAME_LEN]; char cmdname[5]; char name[NAME_LEN]; memcpy(cmdname, buf, 4); cmdname[4] = '\0'; const char* CMD_NAME="name"; if(strcmp(cmdname,CMD_NAME)==0){ char newname[NAME_LEN]; int nameLen = strlen(buf+5); int copyLen; if(nameLen>=NAME_LEN){ copyLen = NAME_LEN-1; }else{ copyLen = nameLen; } memcpy(newname,buf+5,copyLen); newname[copyLen]='\0'; clients.GetName(sock,name,sizeof(name)); sprintf(bufWithName,"%s change name to %s",name,newname); clients.PutName(sock,newname,strlen(newname)); messageBuffer.PutMessage(bufWithName); }else{ clients.GetName(sock,name,sizeof(name)); sprintf(bufWithName,"%s: %s",name,buf); messageBuffer.PutMessage(bufWithName); } } }

编译脚本文件compile

g++ -c MessageBuffer.cpp
g++ -c Clients.cpp
g++ -c Server.cpp
g++ -lpthread -o server MessageBuffer.o Clients.o Server.o

chmod +x compile

./compile 就可以编译并链接

运行服务器

./server 8000

注意Linux下的防火墙iptables服务是否已经启动，如果启动了，需要在/etc/sysconfig/iptables中加入例外端口8000，并重启启动防火墙

/etc/init.d/iptables restart

佟强的高级网络编程课件 http://www.oakcms.cn/network