demo

刺骨的言语ヽ痛彻心扉 2022-05-19 01:13 218阅读 0赞

#include <stdio.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <string.h>
    
    #include <arpa/inet.h>
    
    #define SERVER_PORT 3333
    #define BUFF_LEN 1024
    
    int glbNum = 0;
    char glbBuf[2][16]={'\0'};
    int  glbPort[2] ={0};
    int  dir_num[2] = {0};
    
    void handle_udp_msg(int fd)
    {
        int  a = 2;
        char buf[BUFF_LEN]; 
        socklen_t len;
        int count;
        struct sockaddr_in clent_addr; 
        while(1)
        {
            if(dir_num[0] && dir_num[1])
            {
                break;
            }
        
            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
            if(count == -1)
            {
                printf("recieve data fail!\n");
                return;
            }
            /*不加#include <arpa/inet.h> 会错误！*/
            //printf("client addr:%s, %d\n", inet_ntoa(clent_addr.sin_addr), ntohs(clent_addr.sin_port));
            printf("client:%s\n",buf);  //打印client发过来的信息
            if(glbNum<2)
            {
                memset(buf, 0, BUFF_LEN);
                sprintf(buf, "%s","xintiao");
                //sprintf(buf, "%s,%d\n", inet_ntoa(clent_addr.sin_addr), ntohs(clent_addr.sin_port));  //回复client
                printf("server:%s",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
                
                char tmp_ip[16]={'\0'};
                snprintf(tmp_ip, 16,"%s",  inet_ntoa(clent_addr.sin_addr));
                int tmp_ip_len = strlen(tmp_ip);
                int tmp_port = ntohs(clent_addr.sin_port);
    
                if(glbNum == 0)
                {
    
                    snprintf(glbBuf[glbNum],16,  "%s", tmp_ip);  
                    glbPort[glbNum] = tmp_port;
                    glbNum++;
                }
                else
                {
                    if(!memcmp(glbBuf[0], tmp_ip, tmp_ip_len) && glbPort[0] == tmp_port)
                    {
                        ;
                    }
                    else
                    {
                        sprintf(glbBuf[glbNum], "%s", tmp_ip);  
                        glbPort[glbNum] = tmp_port;
                        glbNum++;
                    }
                }
    
                sleep(1);
            }
            else
            {
               printf("client addr:%s, %d\n", inet_ntoa(clent_addr.sin_addr), ntohs(clent_addr.sin_port));
               if(glbPort[0] != ntohs(clent_addr.sin_port))
               {
                  sprintf(buf, "%s:%d\n", glbBuf[0], glbPort[0]);
                  printf("server:%s",buf);  //打印自己发送的信息给
                  sendto(fd, buf, BUFF_LEN, 0, (struct sockaddr*)&clent_addr, len);
                  dir_num[0] = 1;
               }
               else
               {
                  sprintf(buf, "%s:%d\n", glbBuf[1], glbPort[1]);
                  printf("server:%s",buf);  //打印自己发送的信息给
                  sendto(fd, buf, BUFF_LEN, 0, (struct sockaddr*)&clent_addr, len);
                  dir_num[1]=1;
               }
            }
            sleep(1);
        }    
    }
    
    
    /*
        server:
                socket-->bind-->recvfrom-->sendto-->close
    */
    
    int main(int argc, char* argv[])
    {
        int server_fd, ret;
        struct sockaddr_in ser_addr; 
    
        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); 
        ser_addr.sin_port = htons(SERVER_PORT);
    
        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 <sys/ioctl.h>
    #include <arpa/inet.h>
    #include <unistd.h>
    #include <fcntl.h>
    #include <errno.h>
    #include <stdlib.h>
    
    #define SERVER_PORT 3333
    #define BUFF_LEN 512
    #define SERVER_IP "175.25.***.***"
    #define PORT   6666
    
    void udp_msg_to_third(char *ip, int port)
    {
        int client_fd;
        struct sockaddr_in ser_addr;   
        socklen_t len;
        struct sockaddr_in src;
    
        client_fd = socket(AF_INET, SOCK_DGRAM, 0);
        if(client_fd < 0)
        {
            printf("create socket fail!\n");
            return;
        }
    
        memset(&ser_addr, 0, sizeof(ser_addr));
        ser_addr.sin_family = AF_INET;
        ser_addr.sin_addr.s_addr = inet_addr(ip);
        ser_addr.sin_port = htons(port);  //注意网络序转换
    
        
        struct sockaddr_in thisAddr;  
      
        thisAddr.sin_family = AF_INET;  
        thisAddr.sin_port = htons(PORT);  
        thisAddr.sin_addr.s_addr = htonl(INADDR_ANY);  
    
        if (bind(client_fd,(struct sockaddr_in *)&thisAddr,sizeof(thisAddr)) < 0) {  
            return ;  
        }  
    
        //设置非阻塞模式
        unsigned long ul = 1;  
        ioctl(client_fd, FIONBIO, (unsigned long*)&ul);  
    
    
        while(1)
        {
            char buf[BUFF_LEN] = "i believe you come here clinet1!\n";
            len = sizeof(ser_addr);
            printf("client:%s\n",buf);  //打印自己发送的信息
            int res =sendto(client_fd, buf, BUFF_LEN, 0, (struct sockaddr*)&ser_addr, len);
            if (res < 0) {  
                printf("while sending package to C1 , sendto() failed\n");  
                return ;  
            }else {  
                printf("successfully send package to C1\n");  
            }  
    
            memset(buf, 0, BUFF_LEN);
            res = recvfrom(client_fd, buf, BUFF_LEN, 0, (struct sockaddr*)&src, &len);  //接收来自server的信息
    
            if (len =EAGAIN ) {  
                continue;//未收到回应  
            }else {  
                printf("C1 IP:[%s],PORT:[%d]\n",inet_ntoa(src.sin_addr)  
                    ,ntohs(src.sin_port));  
                printf("C1 says:%s\n", buf);   
            }  
            sleep(5); 
        }
            
        close(client_fd);  
    }
    
    
    void udp_msg_sender(int fd, struct sockaddr* dst)
    {
    
        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
            sendto(fd, buf, BUFF_LEN, 0, dst, len);
            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:%s\n",buf);
    
           if(memcmp(buf, "xintiao", 7))
           {
               char* str = buf;
               int str_len = strlen(buf);
               char* s = strchr(buf, ':');
               char ip[16]={'\0'};
               strncpy(ip, buf, s-str);
               s = s+ 1;
               str_len = str_len -(s-str);
               char port[8]={'\0'};
               strncpy(port, s, str_len);
               printf("ip=%s, port=%d\n", ip, atoi(port));
               close(fd);
               udp_msg_to_third(ip, atoi(port));
           }
           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;
    
        client_fd = socket(AF_INET, SOCK_DGRAM, 0);
        if(client_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 = inet_addr(SERVER_IP);
        //ser_addr.sin_addr.s_addr = htonl(INADDR_ANY);  //注意网络序转换
        ser_addr.sin_port = htons(SERVER_PORT);  //注意网络序转换
    
        struct sockaddr_in thisAddr;  
      
        thisAddr.sin_family = AF_INET;  
        thisAddr.sin_port = htons(PORT);  
        thisAddr.sin_addr.s_addr = htonl(INADDR_ANY);  
    
        //客户端绑定固定端口
        if (bind(client_fd,(struct sockaddr_in *)&thisAddr,sizeof(thisAddr))<0) {  
            return -1;  
        }  
    
        udp_msg_sender(client_fd, (struct sockaddr*)&ser_addr);
    
        close(client_fd);
    
        return 0;
    }