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Linux socket 学习

TCP server

服务端建立步骤一般为：socket->bind->listen->accept

#include <stdio.h>      /* stdin, stdout, stderr */#include <string.h>     /* memset, strerror */#include <sys/types.h>  /* socket, bind, listen, send */#include <sys/socket.h> /* socket, bind, listen, send */#include <netinet/in.h> /* sin_family, sin_port, sin_addr (man in.h) */#include <arpa/inet.h>  /* inet_pton, htons (man inet.h) */#include <errno.h>      /* errno */#define BUFSIZE 1024#define IP      "127.0.0.1"#define PORT    8888#define LISTENQ 5/*  * gcc tcp_server.c -o server  * $ ./server * */int main(int argc, char *argv[]){    int    srv_sockfd;    int    cli_sockfd;    size_t len;    size_t sin_size;    struct sockaddr_in srv_addr;    struct sockaddr_in cli_addr;    char   buf[BUFSIZE];    memset(&srv_addr, 0, sizeof(srv_addr));    srv_addr.sin_family = AF_INET;    inet_pton(AF_INET, IP, &srv_addr.sin_addr);    srv_addr.sin_port = htons(PORT);    /* TCP: socket套接字 */    if ((srv_sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {        fprintf(stderr, "create socket fail, %s.\n", strerror(errno));        return 1;    }    /* bind地址 */    if (bind(srv_sockfd, (struct sockaddr*)&srv_addr,         sizeof(struct sockaddr)) < 0)     {        fprintf(stderr, "create bind fail, %s.\n", strerror(errno));        return 1;    }    /* listen接口 */    listen(srv_sockfd, LISTENQ);    sin_size = sizeof(struct sockaddr_in);    /* 等待客户端连接请求 */    if ((cli_sockfd = accept(srv_sockfd, (struct sockaddr*)&cli_addr,         &sin_size)) < 0)    {        fprintf(stderr, "create accept fail, %s.\n", strerror(errno));        return 1;    }    fprintf(stdout, "accept client %s\n", inet_ntoa(cli_addr.sin_addr));    sprintf(buf, "Hello client, ip:%s\n", inet_ntoa(cli_addr.sin_addr));    len = send(cli_sockfd, buf, strlen(buf), 0);    /* 接受客户端数据 */    memset(&buf, 0, sizeof(char) * BUFSIZE);    while((len = recv(cli_sockfd, buf, BUFSIZE, 0)) > 0) {        buf[len] = '\0';        fprintf(stdout, "%s\n", buf);        if (send(cli_sockfd, buf, len, 0) < 0) { /* 原样发回 */            fprintf(stderr, "create accept fail, %s.\n", strerror(errno));            return 1;        }    }    close(cli_sockfd);    close(srv_sockfd);    return 0;}

TCP client

客户端建立步骤一般为：socket->connect

#include <stdio.h>      /* stdin, stdout, stderr */#include <string.h>     /* memset, strerror */#include <sys/types.h>  /* socket, bind, listen, send */#include <sys/socket.h> /* socket, bind, listen, send */#include <netinet/in.h> /* sin_family, sin_port, sin_addr (man in.h) */#include <arpa/inet.h>  /* inet_pton, htons (man inet.h) */#include <errno.h>      /* errno */#define BUFSIZE 1024#define IP      "127.0.0.1"#define PORT    8888#define LISTENQ 5/*  * gcc tcp_client.c -o client  * $ ./client * */int main(int argc, char *argv[]){    int    cli_sockfd;    size_t len;    struct sockaddr_in srv_addr;    char   buf[BUFSIZE];    memset(&srv_addr, 0, sizeof(srv_addr));    srv_addr.sin_family = AF_INET;    inet_pton(AF_INET, IP, &srv_addr.sin_addr);    srv_addr.sin_port = htons(PORT);    /* TCP: socket套接字 */    if ((cli_sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {        fprintf(stderr, "create socket fail, %s.\n", strerror(errno));        return 1;    }    /* connect server */    if (connect(cli_sockfd, (struct sockaddr*)&srv_addr,         sizeof(struct sockaddr)) < 0)    {        fprintf(stderr, "create connect fail, %s.\n", strerror(errno));        return 1;    }    fprintf(stdout, "connected to server\n");    len = recv(cli_sockfd, buf, BUFSIZE, 0);    buf[len] = '\0';    fprintf(stdout, "%s\n", buf);    while(1) {        fprintf(stdout, "Enter string to send:");        scanf("%s", buf);        len = send(cli_sockfd, buf, strlen(buf), 0);        len = recv(cli_sockfd, buf, BUFSIZE, 0);        buf[len] = '\0';        fprintf(stdout, "received:%s\n", buf);    }    close(cli_sockfd);    return 0;}

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参考资料

[1] http://blog.csdn.net/piaojun_pj/article/details/5920888
[2] http://blog.sina.com.cn/s/blog_50571b1f010082pg.html