6.7.3. tcp socket

socket tcp通信过程如下

6.7.3.1. TCP服务器

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <string.h>
#include <arpa/inet.h>

int main(int argc, char *argv[])
{
    int server_fd, client_fd;
    struct sockaddr_in server_addr;
    struct sockaddr_in client_addr;
    // 1. init server addr
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    server_addr.sin_port = htons(8888);
    int client_addr_len = sizeof(client_addr);
    // 2. create socket
    server_fd = socket(AF_INET, SOCK_STREAM, 0);
    // 3. bind server_addr to server_fd
    bind(server_fd, (struct sockaddr*)&server_addr, sizeof(server_addr));
    // 4. listen server_fd, max listen client num = 10
    listen(server_fd, 10);
    printf("TCP server is listening...\n");
    // 5. accept client connect
    char send_msg[] = "hello client";
    while(1) {
        client_fd = accept(server_fd, (struct sockaddr*)&client_addr, &client_addr_len);
        // 6. send data
        send(client_fd, send_msg, sizeof(send_msg), 0);
        printf("Write %s to client done...\n", send_msg);
        close(client_fd);
    }
    // 8. close server fd
    close(server_fd);
    return 0;
}

6.7.3.2. TCP客户端

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

int main(int argc, char *argv[])
{
    if(argc < 2) {
        printf("Usage: ./tcp_client localhost\n");
        exit(1);
    }
    int server_fd = 0;
    // 1. init client addr
    struct sockaddr_in client_addr;
    client_addr.sin_family = AF_INET;
    struct hostent *myhost = gethostbyname(argv[1]);
    client_addr.sin_addr = (*((struct in_addr*)(myhost->h_addr)));
    client_addr.sin_port = htons(8888);
    // 2. create socket
    server_fd = socket(AF_INET, SOCK_STREAM, 0);
    // 3. connect server
    connect(server_fd, (struct sockaddr*)&client_addr, sizeof(client_addr));
    // 4. recv msg from server
    char msg_buf[100] = { 0 };
    recv(server_fd, msg_buf, 100, 0);
    printf("Client get server msg: %s\n", msg_buf);
    close(server_fd);
}