linux_socket_tcp基础代码_linux tcp socket代码-优快云博客

本文链接：https://blog.youkuaiyun.com/u013127035/article/details/107085814

本文提供了一个TCP套接字编程的详细示例，包括服务器端和客户端代码。通过使用socket、bind、listen、accept等函数，展示了如何创建一个简单的聊天应用，服务器接收并转换客户端发送的消息。

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#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h> // for struct sockaddr_in 
#include <netinet/ip.h> /* superset of previous */
#include <arpa/inet.h>  //for  inet_pton
#include<stdio.h>
#include<ctype.h>
#include<string.h>
#include <unistd.h>

#define SPORT 6666
#define SIP "127.0.0.1"
int main(void)
{
    int sfd = socket(AF_INET,SOCK_STREAM,0);
    if(sfd<0)
    {
        printf("创建套接字失败\n");
        return -1;
    }
    int nfd = 0;
    int ret = 0;
    struct sockaddr_in addr;
    struct sockaddr_in caddr;
    memset(&caddr,0,sizeof(caddr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(SPORT);
    int num = 0;
    ret = inet_pton(AF_INET,SIP,&addr.sin_addr);
    /* inet_pton 这个地方自己老是掉进去,就是这个传入参数,目前我将struct socdaddr_in 中的sin-addr传进去,绑定端口就会成功.*/
    socklen_t clen = sizeof(caddr);
    int n = 0;
    char buf[BUFSIZ];
    memset(buf,0,BUFSIZ); 
    //addr.sin_addr.s_addr=htonl(INADDR_ANY);
    char tmp[128];
    ret = bind(sfd,(struct sockaddr *)&addr,sizeof(addr));
    if(ret <0)
    {
        printf("绑定端口失败\n");
        return -1;
    }
    listen(sfd,128);
    nfd = accept(sfd,(struct sockaddr*)&caddr,&clen);
    printf("客户端端口:%d \n",ntohs(caddr.sin_port));
    inet_ntop(AF_INET,&caddr.sin_addr,tmp,128);
    printf("客户端ip:%s \n",tmp);
    /*这个地方:accept之后,接收到一个客户端连接,之后就会往下走,所以要想实现高并发,
    这个地方需要针对accept 采用多线程多进程 */
    while(1)
    {
        n = read(nfd,buf,sizeof(buf));
        for(int i = 0; i < n;i++)
        {
            buf[i] = toupper(buf[i]);
        }

        write(nfd,buf,n);
    }

    close(nfd);
    close(sfd);
    return 0;
}

客户端代码：

#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/in.h> // for struct sockaddr_in 
#include <netinet/ip.h> /* superset of previous */
#include <arpa/inet.h>  //for  inet_pton
#include<stdio.h>
#include<ctype.h>
#include<string.h>
#include <unistd.h>

#define SPORT 6666
#define SIP "127.0.0.1"
int main(void)
{
    int sfd = socket(AF_INET,SOCK_STREAM,0);
    if(sfd<0)
    {
        printf("创建套接字失败\n");
        return -1;
    }
    char buf[BUFSIZ];
    bzero(buf,BUFSIZ);
    int ret = 0;
    int n = 0;
    struct sockaddr_in addr;
    bzero(&addr,sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(SPORT);
    ret = inet_pton(AF_INET,SIP,&addr.sin_addr);

    connect(sfd,(struct sockaddr*)&addr,sizeof(addr));
    while(1)
    {
        fgets(buf,sizeof(buf),stdin);
        write(sfd,buf,strlen(buf));
        n = read(sfd,buf,strlen(buf));
        write(stdout,buf,n);
    }

    close(sfd);
    return 0;
}