1.server.c服務(wù)器端的代碼

#include<stdio.h>
#include<ctype.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netinet/in.h>
#include<unistd.h>
# define E_MSG(str, value) do{perror(str); return (value);} while(0);

int main(void){
    char buff[128];
    char IP[32];
    struct sockaddr_in serv, clie;
    socklen_t cli_len;

    int s_fd = socket(AF_INET, SOCK_STREAM, 0);
    if(s_fd == -1) E_MSG("socket", -1);
    //對(duì)serv變量的成員進(jìn)行初始化
    serv.sin_family = AF_INET;
    serv.sin_port = htons(8001);
    serv.sin_addr.s_addr = htonl(INADDR_ANY);
    int bb = bind(s_fd, (struct sockaddr *) &serv, sizeof(serv));
    if(bb == -1) E_MSG("bind", -1);
    //將s_fd設(shè)置為被動(dòng)鏈接僧凤，監(jiān)聽客戶端連接
    //將客戶端的連接放入到未決隊(duì)列中
    //此前要定義未決隊(duì)列的長度
    listen(s_fd, 5);
    while(1){
        cli_len = sizeof(clie);
        //從未決隊(duì)列中取出一個(gè)連接處理
        //返回這個(gè)連接的描述符瘪贱，使用該描述符和客戶端通信
        int c_fd = accept(s_fd, (struct sockaddr *)&clie, &cli_len);
        if(c_fd == -1) E_MSG("accept", -1);
        //到此時(shí)涡扼，三次握手成功怯伊，可以傳輸數(shù)據(jù)
        //從c_fd中讀取客戶端發(fā)來的數(shù)據(jù)
        //二進(jìn)制轉(zhuǎn)換成字符
        inet_ntop(AF_INET, &clie.sin_addr, IP, 32);
        printf("Cleint ip: %s\n", IP);
        int r = read(c_fd, buff, 128);
        int i;
        for(i = 0; i < r; i++){
            buff[i] = toupper(buff[i]);
        }
        //將處理結(jié)果回送
        write(c_fd, buff, r);
        close(c_fd);
    }
    return 0;
}

2.client.c

#include<stdio.h>
#include<string.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>

int main(void){
    char buff[128];
    struct sockaddr_in serv;
    char *msg = "hello sky walker...\n";
    //create an socket connection, return file descriptor;
    int fd = socket(AF_INET, SOCK_STREAM, 0);
    if(fd == -1) return -1;

    serv.sin_family = AF_INET;
    serv.sin_port = htons(8001);
    //二進(jìn)制轉(zhuǎn)換
    inet_pton(AF_INET, "127.0.0.1", &serv.sin_addr);
    //使用fd向服務(wù)器發(fā)起連接
    int c = connect(fd, (struct sockaddr *)&serv, sizeof(serv));
    if(c == -1) return -1;
    //三次握手成功岸霹，向服務(wù)器發(fā)送數(shù)據(jù)
    write(fd, msg, strlen(msg) + 1);
    //等待服務(wù)器回應(yīng)
    int r = read(fd, buff, 128);
    write(1, buff, r);
    close(fd);

    return 0;
}