实现TCP的C代码封装（含代码）

tcp_socket.h：

#ifndef TCP_SCOKET_H
#define TCP_SCOKET_H

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define MAX_CONNECT_NUM 10

int tcp_init(const char* ip, int port);
int tcp_accept(int sfd);
int tcp_connect(const char* ip, int port);
int tcp_nonblocking_recv(int conn_sockfd, 
                         void *rx_buf, 
                         int buf_len, 
                         int timeval_sec, 
                         int timeval_usec);
int tcp_blocking_recv(int conn_sockfd, void *rx_buf, uint16_t buf_len);
int tcp_send(int conn_sockfd, uint8_t *tx_buf, uint16_t buf_len);
void tcp_close(int sockfd);

#endif

tcp_socket.c：

#include "tcp_socket.h"

int tcp_init(const char* ip, int port)
{
    int optval = 1; 
    int server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd < 0)
    {
        perror("socket");
        return -1;
    }

    /* 解除端口占用 */
    if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &optval, sizeof(optval)) < 0)
 {
  perror("setsockoptn");
  return -1;
 }

    struct sockaddr_in server_addr;
    bzero(&server_addr, sizeof(struct sockaddr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(port);
    if (NULL == ip)
    {
        server_addr.sin_addr.s_addr = htonl(INADDR_ANY); 
    }
    else
    {
        server_addr.sin_addr.s_addr = inet_addr(ip); 
    }

    if (bind(server_fd, (struct sockaddr*)&server_addr,sizeof(struct sockaddr)) < 0)
    {
        perror("bind");
        close(server_fd);
        return -1;
    }

    if(listen(server_fd, MAX_CONNECT_NUM) < 0)
    {
        perror("listen");
        close(server_fd);
        return -1;
    }

    return server_fd;
}

int tcp_accept(int server_fd)
{
    struct sockaddr_in client_addr = {0};
    int addrlen = sizeof(struct sockaddr);
    int new_fd = accept(server_fd, (struct sockaddr*) &client_addr, &addrlen);
    if(new_fd < 0)
    {
        perror("accept");
        close(server_fd);
        return -1;
    }
    
    return new_fd;
}

int tcp_connect(const char *ip, int port)
{
    int server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd < 0)
    {
        perror("socket");
        return -1;
    }

    struct sockaddr_in server_addr;
    bzero(&server_addr, sizeof(struct sockaddr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(port);
    server_addr.sin_addr.s_addr = inet_addr(ip);

    if (connect(server_fd, (struct sockaddr*)&server_addr, sizeof(struct sockaddr)) < 0)
    {
        perror("connect");
        close(server_fd);
        return -1;
    }

    return server_fd;
}

int tcp_nonblocking_recv(int conn_sockfd, void *rx_buf, int buf_len, int timeval_sec, int timeval_usec)
{
 fd_set readset;
 struct timeval timeout = {0, 0};
 int maxfd = 0;
 int fp0 = 0;
 int recv_bytes = 0;
 int ret = 0;
 
 timeout.tv_sec = timeval_sec;
 timeout.tv_usec = timeval_usec;
 FD_ZERO(&readset);           
 FD_SET(conn_sockfd, &readset);         

 maxfd = conn_sockfd > fp0 ? (conn_sockfd+1) : (fp0+1);    

 ret = select(maxfd, &readset, NULL, NULL, &timeout); 
 if (ret > 0) 
    {
  if (FD_ISSET(conn_sockfd, &readset)) 
        {
   if ((recv_bytes = recv(conn_sockfd, rx_buf, buf_len, MSG_DONTWAIT))== -1) 
            {
    perror("recv");
    return -1;
   }
  }
 } 
    else 
    {
  return -1;
 }
 
 return recv_bytes;
}

int tcp_blocking_recv(int conn_sockfd, void *rx_buf, uint16_t buf_len)
{
    return recv(conn_sockfd, rx_buf, buf_len, 0);
}

int tcp_send(int conn_sockfd, uint8_t *tx_buf, uint16_t buf_len)
{
    return send(conn_sockfd, tx_buf, buf_len, 0);
}

void tcp_close(int sockfd)
{
    close(sockfd);
}

x下面测试代码：

#include "tcp_socket.h"

int main(int argc, char **argv)
{
    printf("==================tcp server==================n");
    int server_fd = tcp_init(NULL, 4321);
    if (server_fd < 0)
    {
        printf("tcp_init error!n");
        exit(EXIT_FAILURE);
    }

    int client_fd = tcp_accept(server_fd);
    if (client_fd < 0)
    {
        printf("tcp_accept error!n");
        exit(EXIT_FAILURE);
    }

    while (1)
    {
        char buf[128] = {0};
        
        int recv_len = tcp_blocking_recv(client_fd, buf, sizeof(buf));
        if (recv_len <= 0)
        {
            printf("recv error!n");
            tcp_close(client_fd);
            tcp_close(server_fd);
            exit(EXIT_FAILURE);
        }
        printf("recv : %sn", buf);

        int send_len = tcp_send(client_fd, buf, strlen(buf));
        if (send_len <= 0)
        {
            printf("send error!n");
            tcp_close(client_fd);
            tcp_close(server_fd);
            exit(EXIT_FAILURE);  
        }
        else
        {
            printf("send success! send: %s, send_len: %dn", buf, send_len);
        }
    }
    tcp_close(server_fd);

    return 0;
}

tcp_client.c：

#include "tcp_socket.h"

int main(int argc, char **argv)
{
    printf("==================tcp cient==================n");
    if (argc < 3)
    {
        printf("usage:./tcp_client ip portn");
        exit(EXIT_FAILURE);
    }

    char ip_buf[32] = {0};
    int port = 0;

    memcpy(ip_buf, argv[1], strlen(argv[1]));
    port = atoi(argv[2]);

    int server_fd = tcp_connect(ip_buf, port);
    if (server_fd < 0)
    {
        printf("tcp_connect error!n");
        exit(EXIT_FAILURE);
    }

    while (1)
    {
        char buf[128] = {0};
        if (scanf("%s", buf))
        {
            int send_len = tcp_send(server_fd, buf, strlen(buf));
            if (send_len <= 0)
            {
                printf("tcp_send error!n");
                tcp_close(server_fd);
                exit(EXIT_FAILURE);  
            }
            else
            {
                printf("send success! send: %s, send_len: %dn", buf, send_len);
            }

            bzero(buf, sizeof(buf));
            int recv_len = tcp_blocking_recv(server_fd, buf, sizeof(buf));
            if (recv_len <= 0)
            {
                printf("tcp_blocking_recv error!n");
                tcp_close(server_fd);
                exit(EXIT_FAILURE);
            }
            printf("recv : %sn", buf);
        } 
    }

    return 0;
}