Linux下C语言实现TCP通信

来源：互联网发布：徐水网络互动平台编辑：程序博客网时间：2024/05/03 11:42

TCP编程：
写一个tcp的服务端，一个tcp客户端。
客户端连接到服务端，然后每隔2s向服务端发送消息：

#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <netdb.h>#define SERVER_IP "127.10.10.11"#define PORT 12345#define MAXDATASIZE 512int main(){    int fd;    int num;    char recebuf[MAXDATASIZE];    char sendbuff[200];    int number = 1;    struct hostent *he;   //the struct that will get information about remote host    struct sockaddr_in  server;    if ((fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)    {        printf("create socket error!\n");        exit(1);    }    bzero(&server, sizeof(server));    server.sin_family = AF_INET;    server.sin_port = htons(PORT);    //server.sin_addr = *((struct in_addr *)he->h_addr);    server.sin_addr.s_addr = inet_addr(SERVER_IP);    //start to conncet     if(connect(fd, (struct sockaddr *)&server, sizeof(server)) == -1)    {        printf("connect error\n");        exit(1);    }    while(1)    {    //start to send message    snprintf(sendbuff, sizeof(sendbuff), "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n                                          <request id=\"%d\" type=\"connect\">\n                                          <say>I am client!</say>\n                                          </request>"                                        ,number);    //printf("%s\n", sendbuff);    num = send(fd, sendbuff, sizeof(sendbuff), 0);    if(num == -1)    {        printf("send message error\n");    }    //start to receive message     num = recv(fd, recebuf, MAXDATASIZE, 0);    if(num == -1)    {        printf("receive message error\n");        exit(-1);    }    recebuf[num] = '\0';    printf("\n\n接收到的回复是：\n");    printf("%s\n\n", recebuf);    sleep(2);    number++;    }    close(fd);    return 0;}

下面是服务器代码：

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <sys/time.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <netdb.h>#include <arpa/inet.h>#define PORT 12345#define MAXDATASIZE 512#define BACKLOG 1void setresponse(char rece[], char send[]){    char str1[] = "request";    char str2[] == "client";    char dest1[] = "response";    char dest2[] = "server";    int i1 = 0, i2 = 0;    int j1 = 0, j2 = 0;    int flag_send = 0;    int flag_dest1 = 0, flag_dest2 = 0;    //match the str request    while(rece[i1] != '\0')    {        if(rece[i1] == str1[j1])        {            i1++;            j1++;            if(str1[j1] == '\0')            {                break;            }        }        else        {            i1++;            j1 = 0;        }    }    //match the str client    while(rece[i2] != '\0')    {        if(rece[i2] == str2[j1])        {            i2++;            j2++;            if(str2[j2] == '\0')            {                break;            }        }        else        {            i2++;            j2 = 0;        }    }    //start to conncet the str before response    while(flag_send < (i1-j1))    {        send[flag_send] = rece[flag_send];        flag_send++;    }    // start to connect the str response    while(dest1[flag_dest1] != '\0')    {        send[flag_send] = dest1[flag_dest1];        flag_dest1++;        flag_send++;    }    //start to connect the str between response and server    while(i1 < (i2-j2))    {        send[flag_send] = rece[i1+1];        i1++;        flag_send++;    }    // start to connect the str server    while(dest2[flag_dest2] != '\0')    {        send[flag_send] = dest2[flag_dest2];        flag_dest2++;        flag_send++;    }    //start to connect the str after server    while(rece[i2] != '\0')    {        send[flag_send] = rece[i2];        flag_send++;        i2++;    }    send[flag_send] = '\0';}int main(){    char recebuf[MAXDATASIZE];    char sendbuff[200];    int listenfd, connectfd;    struct sockaddr_in server; //server's address information    struct sockaddr_in client;  // client's address information    socklen_t addrlen;    /*create tcp socket*/    if((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)    {        printf("create socket failed\n");        exit(1);    }    //set socket options    int opt = SO_REUSEADDR;    setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));    bzero(&server, sizeof(server));    server.sin_family = AF_INET;    server.sin_port = htons(PORT);    server.sin_addr.s_addr = htonl(INADDR_ANY);    //bind socket    if(bind(listenfd, (struct sockaddr *)&server, sizeof(server)) == -1)    {        printf("bind error\n");        exit(1);    }    //listen scoket    if(listen(listenfd, BACKLOG) == -1)    {        printf("listen error\n");        exit(1);    }    addrlen = sizeof(client);    while(1)    {        //conncet the socket        if((connectfd = accept(listenfd, (struct sockaddr *)&client, &addrlen)) == -1)        {            printf("accept error\n");            exit(1);        }        struct timeval tv;        gettimeofday(&tv, NULL);        printf("you got a connnetion from client's ip %s, port %d at time %ld.%ld\n", inet_ntoa(client.sin_addr), htons(client.sin_port),            tv.tv_sec, tv.tv_usec);        int iret = -1;        while(1)        {            iret = recv(connectfd, recebuf, MAXDATASIZE, 0);            if(iret > 0)            {                printf("%s\n", recebuf);            }            else            {                close(connectfd);                break;            }            setresponse(recebuf, sendbuff);            send(connectfd, recebuf, iret, 0);        }           }    close(listenfd);    return 0;}

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