tcp_server和tcp_client

tcp_server代碼如下：

#include<stdio.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<sys/types.h>
#include<string.h>

static void usage(const char *proc)
{
    printf("Usage: %s [local_ip] [local_port]\n",proc);
}

int startup(const char *ip,int port)
{
    int sock = socket(AF_INET,SOCK_STREAM, 0);
        if(sock < 0){
            perror("socket");
            exit(2);
        }

    struct sockaddr_in local;
    local.sin_family = AF_INET;
    local.sin_port = htons(port);
    local.sin_addr.s_addr = inet_addr(ip);

    if(bind(sock, (struct sockaddr*)&local, sizeof(local))<0){
        perror("bind");
        exit(3);
    }
    if(listen(sock, 10)<0){
        perror("listen");
        exit(4);
    }
    return sock;
}

// ./tcp_server ip port
int main(int argc, char *argv[])
{
    if(argc != 3){
        usage(argv[0]);
        return 1;
    }
int listen_sock = startup(argv[1],atoi(argv[2]));

while(1){
    struct sockaddr_in client;
    socklen_t len = sizeof(client);

    int new_sock = accept(listen_sock,\
            (struct sockaddr*)&client, &len);
    if(new_sock < 0){
        perror("accept");
        continue;
    }
    printf("get a new cilent, %s:%d\n",\
            inet_ntoa(client.sin_addr), ntohs(client.sin_port));

    while(1){
        char buf[1024];
        ssize_t s = read(new_sock, buf, sizeof(buf)-1);
        if(s>0){
            buf[s] = 0;
            printf("client: %s\n", buf);
            write(new_sock, buf, strlen(buf));
        }else if(s == 0){
            close(new_sock);
            printf("client quit...\n");
            break;
        }else{
            perror("read");
            close(new_sock);
            break;
        }
    }
}
}

****

tcp_client代碼如下：

#include<stdio.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<sys/types.h>
#include<string.h>

static void usage(const char *proc)
{
    printf("Usage:%s[server_ip][server_port]\n",proc);
}
//./tcp client server-ip server-port
int main(int argc,char *argv[])
{
    if(argc !=3){
    usage(argv[0]);
    return 1;
    }

    int sock = socket(AF_INET,SOCK_STREAM,0);
    if(sock<0){
    perror("socket");
    return 1;
    }
    struct sockaddr_in server;
    server.sin_family = AF_INET;
    server.sin_port = htons(atoi(argv[2]));
    server.sin_addr.s_addr = inet_addr(argv[1]);
    if(connect(sock,(struct sockaddr*)&server,\
                sizeof(server))<0){
        perror("connect");
        return 2;
    }
    char buf[1024];
    while(1){
        printf("Please Enter# ");
        fflush(stdout);
        ssize_t s = read(0,buf,sizeof(buf)-1);
        if(s>0){
        buf[s-1] = 0;
        write(sock, buf, strlen(buf));
        s = read(sock, buf, sizeof(buf)-1);
        if(s>0){
        buf[s] = 0;
        printf("server echo# %s\n",buf);
        }
        }
    }
}

client終止時自動關閉socket描述符，server的tcp 連接收到client發的FIN段後處於TIME_WITE狀態。