Linux C/C++网络编程基础 UDP简单实现

简单的linux下socket编程，分别基于TCP协议实现的简单程序

linux下socket编程可以概括为以下几个函数的运用：

• socket()
• bind()
• listen()
• connect()
• accept()
• read()
• write()
• close()函数

server端

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

#define BUFFSIZE 1024

int main(int argc, char *argv[])
{
    int server_sockfd = 0;
    int len = 0;
    int sin_size = 0;
    struct sockaddr_in server_addr;
    struct sockaddr_in client_addr;
    char buf[BUFFSIZE] = {0};

    bzero(&server_addr, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = INADDR_ANY;
    server_addr.sin_port = htons(8000);

    if((server_sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
    {
        perror("socket error!\n");
        return -1;
    }

    if(bind(server_sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) < 0)
    {
        perror("bind error!\n");
        return -1;
    }

    sin_size= sizeof(struct sockaddr_in);
    while(1)
    {
        if((len = recvfrom(server_sockfd, buf, BUFFSIZE, 0, (struct sockaddr*)&client_addr, &sin_size)) < 0)
        {
            perror("recvfrom error!\n");
            return -1;
        }

        printf("recv from: %s\n",inet_ntoa(client_addr.sin_addr));
        buf[len] = '\0';
        printf("recv is: %s\n",buf);
        if(len <= 0)
        {
            break;
        }
    }
    close(server_sockfd);

    return 0;
}

client端

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

#define BUFFSIZE 1024

int main(int argc, char *argv[])
{
    int client_sockfd = 0;
    int len = 0;
    struct sockaddr_in server_addr;
    int sin_size = 0;
    char buf[BUFFSIZE] = {0};
    bzero(&server_addr, sizeof(struct sockaddr_in));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    server_addr.sin_port = htons(8000);

    if((client_sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
    {
        perror("socket error!\n");
        return -1;
    }

    sin_size = sizeof(struct sockaddr_in);
    
    while(1)
    {
        scanf("%s",buf);
        if(!strcmp(buf,"quit"))
        {
            break;
        }
        
        if((len = sendto(client_sockfd, buf, strlen(buf), 0 ,(struct sockaddr*)&server_addr, sizeof(struct sockaddr))) < 0)
        {
            perror("sendto fail!\n");
            return -1;
        }
    }

    close(client_sockfd);

    return 0;
}