Dear all,

I want to receive UDP-packets from a multicast message. The system currently 
can receive unicast messages.

To receive multicast messages I've set the following settings in lwipopts.h
  #define LWIP_IGMP                       1
  #define MEMP_NUM_IGMP_GROUP             8

Also in the initialize function I've set the right flag
  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_UP | 
NETIF_FLAG_IGMP | NETIF_FLAG_ETHERNET;

The initializing of the IGMP-group is as follows
 uint16 port;
  ip_addr_t groupAddress;

  getParamatersFromTransmissionGroup (group, &port, &groupAddress);
  __udpSocket = udp_new ();
  MF_ASSERT (__udpSocket != NULL);

  err_t err = udp_bind (__udpSocket, IP_ADDR_ANY, port);
  MF_ASSERT (err == ERR_OK);

  err = igmp_joingroup (&localAddr, &groupAddress);
  MF_ASSERT (err == ERR_OK);

  udp_recv (__udpSocket, data_received, this);

When I send data directly to the IP address assigned in LWIP I get to the 
breakpoint in data_received.
However when I change the destination IP address to the one configured in 
groupAddress, I get no data at all.

I've made some tests in Wireshark where I captured the packets. The test system 
consists of three devices
192.168.172.1 > Router
192.168.172.20 > Computer with Wireshark
192.168.172.113 > LWIP Device
I've attached the capturefile done in Wireshark, In this file you can see the 
LWIP device responds to a query.
If you need any more information, please reply to this mail.

Met vriendelijke groet, Best regards,

Ricardo Schoof | R&D Engineer

Attachment: capture.pcapng
Description: capture.pcapng

_______________________________________________
lwip-users mailing list
[email protected]
https://lists.nongnu.org/mailman/listinfo/lwip-users

Reply via email to