基於tcp的簡單socket通訊

socket即ip+port，當然這是最直接的理解，網路的通訊都離不開使用到socket，下面的聊天程式是基於tcp的簡單通訊過程，伺服器端建立兩個socket描述符，一個用於在伺服器端監聽，另一個用來接收用戶端串連的請求。用戶端使用connect函數向伺服器發出串連請求，這裡麵包含了tcp的三向交握過程，串連完成之後就是cs間的相互連信了。

/****************************************************//*server.c*//*@2013-03-23*//****************************************************/#include<sys/socket.h>//提供socket函數及資料結構#include<sys/types.h>//資料類型定義#include<stdio.h>#include<stdlib.h>#include<string.h>#include<netinet/in.h>//定義資料結構sockaddr_in#include<arpa/inet.h>//提供ip地址轉換函式#define BUFSIZE 100int srv_sockfd,client_sockfd;//通訊端描述符char recvBuf[BUFSIZE],sendBuf[BUFSIZE];struct sockaddr_in srv_addr;//伺服器通訊端地址struct sockaddr_in client_addr;//建立tcp通訊端int tcpServer(){    memset(&srv_addr,0,sizeof(srv_addr));    srv_addr.sin_family = AF_INET;    srv_addr.sin_addr.s_addr = INADDR_ANY;    srv_addr.sin_port = htons(8889);    if((srv_sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)    {        perror("socket creation failed");        return 1;    }    //設定通訊端選項，避免地址使用錯誤    int on=1;    if((setsockopt(srv_sockfd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(int))) < 0)    {        perror("setsockopt failed");        return 1;    }        //綁定通訊端到伺服器的網路地址上    if((bind(srv_sockfd,(struct sockaddr *)&srv_addr,sizeof(struct sockaddr))) <0)    {        perror("bind failed");        return 1;    }    //建立監聽隊列    listen(srv_sockfd,5);    //等待用戶端連結請求int sin_size=sizeof(struct sockaddr_in);    client_sockfd = accept(srv_sockfd,(struct sockaddr *)&client_addr,(socklen_t *)&sin_size);        if(client_sockfd < 0)    {        perror("accept failed");        return 1;    }    return client_sockfd;}//通訊過程int communicate(int sockfd){    while(1)    {        if(( recv(sockfd,recvBuf,BUFSIZE,0)) < 0)       {           perror("recv failed");           return 1;       }       if(recvBuf[0] == 'q'&& recvBuf[1] == '\0')//保證只是輸入q時候才結束聊天       {           send(sockfd,"q",strlen("q")+1,0);           printf("Chat end!\n");           break;       }       printf("%s : %s\n",inet_ntoa(client_addr.sin_addr),recvBuf);      //發送資料給用戶端       printf("I :");       scanf("%s",sendBuf);       if((send(sockfd,sendBuf,BUFSIZE,0)) < 0)       {           perror("send failed");           return 1;       }    }    return 0;}int main(){    printf("Waiting for connection...\n");   int clientfd= tcpServer();   if(clientfd != 1)   {       printf("welcome %s to connect\n",inet_ntoa(srv_addr.sin_addr));       communicate(clientfd);       close(client_sockfd);       close(srv_sockfd);   }    return 0;}

/****************************************************//*client.c*//*@2013-03-23*//****************************************************/#include<sys/types.h>#include<sys/socket.h>#include<netinet/in.h>#include<arpa/inet.h>#include<stdio.h>#include<stdlib.h>#include<string.h>#include<unistd.h>#define BUFSIZE 100char sendBuf[BUFSIZE];char recvBuf[BUFSIZE];struct sockaddr_in srv_addr;//伺服器端網路地址int client_sockfd;//用戶端通訊端描述符int re;//建立tcp通訊端並串連伺服器int tcpClient(){    client_sockfd = socket(AF_INET,SOCK_STREAM,0);    srv_addr.sin_family = AF_INET;    srv_addr.sin_addr.s_addr = inet_addr("127.0.0.1");    srv_addr.sin_port = htons(8889);    int len = sizeof(srv_addr);    //與伺服器連結   if(( re = connect(client_sockfd,(struct sockaddr *)&srv_addr,len)) < 0)   {       perror("connect failed");       return 1;   }   return client_sockfd;}//開始通訊int communicate(int sockfd){    while(1)    {        printf("I :");        scanf("%s",sendBuf);        if((send(client_sockfd,sendBuf,BUFSIZE,0)) < 0)        {            perror("send failed");            return 1;        }        //等待接收資料        if((recv(client_sockfd,recvBuf,BUFSIZE,0)) < 0)        {            perror("recv failed");            return 1;        }        if(recvBuf[0] == 'q'&& recvBuf[1] == '\0')//保證只是輸入q的時候才結束聊天        {            send(client_sockfd,"q",strlen("q")+1,0);            printf("Chat end!\n");            break;        }        printf("%s : %s\n",inet_ntoa(srv_addr.sin_addr),recvBuf);    }}int main(){    int clientfd = tcpClient();    if(clientfd != 1)    {        printf("success connect to %s...\n",inet_ntoa(srv_addr.sin_addr));        communicate(clientfd);        close(client_sockfd);    }    return 0;}