尽管tcpdump上显示流量，但连接到同一交换机的其他设备的多播recv仍然无法正常工作

我正在尝试从连接到与我的桌面相同的交换机的嵌入式设备接收多播数据，并且无法在下面的我的recv应用程序上接收多播消息 . 当我对连接到交换机的接口执行tcpdump或运行Wireshark时，我看到数据包显示但由于某种原因它们不在我的应用程序中 .

我正在使用INADDR_ANY作为接口地址 . 有人可以解释为什么消息将在Wireshark / Tcpdump上但应用程序没有收到？

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

#define UDP_PORT 5403
#define UDP_GROUP "225.0.0.1"
#define MAX_BUFFER_SIZE 256

int main(int argc, char *argv[])
{
     struct sockaddr_in addr;
     int fd, nbytes;
     socklen_t addrlen;
     struct ip_mreq mreq;
     char msgbuf[MAX_BUFFER_SIZE];
     u_int reuse_port = 1;

     // Create a socket
     fd = socket(AF_INET,SOCK_DGRAM,0);
     if (fd < 0)
     {
        perror("create socket failed");
        return -1;
     }

     // allow multiple sockets to use the same PORT number
     if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &reuse_port, sizeof(reuse_port)) < 0)
     {
        perror("Reusing port number failed");
        return -1;
     }

     // set up destination address
     memset(&addr, 0, sizeof(addr));
     addr.sin_family = AF_INET;
     addr.sin_addr.s_addr = htonl(INADDR_ANY);
     addr.sin_port = htons(UDP_PORT);
     if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0)
     {
        perror("bind");
        return -1;
     }

     // Set the recvfrom timeout after 1 s
     struct timeval tv;
     tv.tv_sec = 2;
     tv.tv_usec = 0;
     if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)) < 0)
     {
         perror("Error setting recvfrom timeout\n");
         return -1;
     }

     // use setsockopt() to request that the kernel join a multicast group
     mreq.imr_multiaddr.s_addr = inet_addr(UDP_GROUP);
     mreq.imr_interface.s_addr = htonl(INADDR_ANY);
     if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
     {
        perror("setsockopt");
        return -1;
     }

     addrlen = sizeof(addr);
     printf("Begin recvfrom(...) infinite loop\n");
     while (true)
     {
         nbytes = recvfrom(fd, msgbuf, MAX_BUFFER_SIZE, 0, (struct sockaddr *)&addr, &addrlen);
         if (nbytes < 0)
         {
            printf("recvfrom timeout\n");
         }
         else
         {
            printf("message received: %s\n", msgbuf);
         }
     }
     return 1;
}