Socket之UDP服务器代码框架

server

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


#define SERVER_PORT 8888
#define BUFF_LEN 1024

void handle_udp_msg(int fd)
{
    char buf[BUFF_LEN];  //接收缓冲区，1024字节
    socklen_t len;
    int count;
    struct sockaddr_in clent_addr;  //clent_addr用于记录发送方的地址信息
    while(1)
    {
        memset(buf, 0, BUFF_LEN);
        len = sizeof(clent_addr);
        count = recvfrom(fd, buf, BUFF_LEN, 0, (struct sockaddr*)&clent_addr, &len);  //recvfrom是拥塞函数，没有数据就一直拥塞
        printf("Client IP:%s\r\n",inet_ntoa(clent_addr.sin_addr));
        printf("Client port:%d\r\n",ntohs(clent_addr.sin_port));
        if(count == -1)
        {
            printf("recieve data fail!\n");
            return;
        }
        printf("client:%s\n",buf);  //打印client发过来的信息
        memset(buf, 0, BUFF_LEN);
        sprintf(buf, "I have recieved %d bytes data!\n", count);  //回复client
        printf("server:%s\n",buf);  //打印自己发送的信息给
        sendto(fd, buf, BUFF_LEN, 0, (struct sockaddr*)&clent_addr, len);  //发送信息给client，注意使用了clent_addr结构体指针
    }
}

/*
    server:
            socket-->bind-->recvfrom-->sendto-->close
*/

int main(int argc, char* argv[])
{
    int server_fd, ret;
    struct sockaddr_in ser_addr; 
    //creat socket
    server_fd = socket(AF_INET, SOCK_DGRAM, 0); //AF_INET:IPV4;SOCK_DGRAM:UDP
    if(server_fd < 0)
    {
        printf("create socket fail!\n");
        return -1;
    }

    memset(&ser_addr, 0, sizeof(ser_addr));
    ser_addr.sin_family = AF_INET;
    ser_addr.sin_addr.s_addr = htonl(INADDR_ANY); //IP地址，需要进行网络序转换，INADDR_ANY：本地地址
    ser_addr.sin_port = htons(SERVER_PORT);  //端口号，需要网络序转换

    ret = bind(server_fd, (struct sockaddr*)&ser_addr, sizeof(ser_addr));
    if(ret < 0)
    {
        printf("socket bind fail!\n");
        return -1;
    }

    handle_udp_msg(server_fd);   //处理接收到的数据

    close(server_fd);
    return 0;
}

client

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


#define SERVER_PORT 8888
#define BUFF_LEN 512



void udp_msg_sender(int fd, struct sockaddr* dst)
{
    int count=0;
    socklen_t len;
    struct sockaddr_in src;
    while(1)
    {
        char buf[BUFF_LEN] = "TEST UDP MSG!\n";
        len = sizeof(*dst);
        printf("client:%s\n",buf);  //打印自己发送的信息
        count=sendto(fd, buf, BUFF_LEN, 0, dst, len);//send message to server
        memset(buf, 0, BUFF_LEN);
        recvfrom(fd, buf, BUFF_LEN, 0, (struct sockaddr*)&src, &len);  //接收来自server的信息
        printf("Server_IP:%s\r\n",inet_ntoa(src.sin_addr));
        printf("Server_port:%d\r\n",ntohs(src.sin_port));
        printf("Send %d bytes data\n",count);
        printf("server:%s\n",buf);
        sleep(1);  //一秒发送一次消息
    }
}

/*
    client:
            socket-->sendto-->revcfrom-->close
*/

int main(int argc, char* argv[])
{
    int client_fd;
    struct sockaddr_in ser_addr;
    struct sockaddr_in cli_addr;
    //creat socket
    client_fd = socket(AF_INET, SOCK_DGRAM, 0);
    if(client_fd < 0)
    {
        printf("create socket fail!\n");
        return -1;
    }
    //配置要连接到主机信息
    memset(&ser_addr, 0, sizeof(ser_addr));
    ser_addr.sin_family = AF_INET;
    //ser_addr.sin_addr.s_addr=inet_addr("192.168.224.130");
    ser_addr.sin_addr.s_addr=inet_addr("127.0.0.1");
    //ser_addr.sin_addr.s_addr = htonl(INADDR_ANY);  //注意网络序转换//INADDR_ANY is local IP
    ser_addr.sin_port = htons(SERVER_PORT);  //注意网络序转换

    //配置客户端信息
    memset(&cli_addr, 0, sizeof(cli_addr));
    cli_addr.sin_family = AF_INET;
    //cli_addr.sin_addr.s_addr=inet_addr("192.168.224.130");
    cli_addr.sin_addr.s_addr=inet_addr("127.0.0.1");
    //cli_addr.sin_addr.s_addr = htonl(INADDR_ANY);  //注意网络序转换//INADDR_ANY is local IP
    cli_addr.sin_port = htons(9999);  //注意网络序转换
    bind(client_fd, (struct sockaddr*)&cli_addr, sizeof(cli_addr));

    //do job...
    udp_msg_sender(client_fd, (struct sockaddr*)&ser_addr);

    close(client_fd);

    return 0;
}