客户端停止发送数据?

我正在尝试将模拟数据从客户端发送到服务器,并使用UDP进行完美连接。我每发三次邮件就会引起一次包裹丢失。如果我取消对recv部分的注释,它只会在发送一次后停止!我不知道为什么。我包含了双方的代码,并注释掉了recv部分。

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

#define PORT     8080
#define MAXLINE 1024

// Driver code
int main() {
    int sockfd;
    char buffer[MAXLINE];
    char *hello = "Hello from server";
    struct sockaddr_in servaddr, cliaddr;

    // Creating socket file descriptor
    if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) {
        perror("socket creation failed");
        exit(EXIT_FAILURE);
    }

    memset(&servaddr, 0, sizeof(servaddr));
    memset(&cliaddr, 0, sizeof(cliaddr));

    // Filling server information
    servaddr.sin_family    = AF_INET; // IPv4
    servaddr.sin_addr.s_addr = INADDR_ANY;
    servaddr.sin_port = htons(PORT);

    // Bind the socket with the server address
    if ( bind(sockfd, (const struct sockaddr *)&servaddr,
            sizeof(servaddr)) < 0 )
    {
        perror("bind failed");
        exit(EXIT_FAILURE);
    }

    int len, n;
    while(1){

        n = recvfrom(sockfd, (char *)buffer, MAXLINE,
            0, ( struct sockaddr *) &cliaddr,
            &len);
        printf("Client : %s\n", buffer);
        bzero(buffer,sizeof(buffer));
        sendto(sockfd, (const char *)hello, strlen(hello),
            0, (const struct sockaddr *) &cliaddr,
            len);
    }

    return 0;
}

客户:

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

#define PORT     8080
#define MAXLINE 1024

// Driver code
int main() {
    int sockfd;
    char buffer[MAXLINE];
    char *hello = "PING";
    char *pocketLoss = "Pocket Loss";
    struct sockaddr_in     servaddr;
    int worked = 0;
    int notWorked = 0;
    // Creating socket file descriptor
    if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) {
        perror("socket creation failed");
        exit(EXIT_FAILURE);
    }

    memset(&servaddr, 0, sizeof(servaddr));

    // Filling server information
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(PORT);
    servaddr.sin_addr.s_addr = INADDR_ANY;

    int n, len;
    int counter = 0;
    while(1){
        if(counter%3 != 0){
            sendto(sockfd, (const char *)hello, strlen(hello),
                0, (const struct sockaddr *) &servaddr,
                sizeof(servaddr));
            sleep(2);
            worked = worked + 1;
        }else{
            sendto(sockfd, (const char *)pocketLoss, strlen(pocketLoss),
                0, (const struct sockaddr *) &servaddr,
                sizeof(servaddr));
            sleep(2);
            notWorked = notWorked + 1;
        }
        counter = counter + 1;
        printf("STTTILL");
        n = recvfrom(sockfd, buffer, MAXLINE, 0, NULL, NULL);
    }

    printf("%d %d\n",worked,notWorked);
    buffer[n] = '\0';
    printf("Server : %s\n", buffer);
    close(sockfd);
    return 0;
}