W7500(P) Get destination IP of received UDP packet

Question

Hi all, When receiving an UDP message with the recvfrom() method, the IP and port of the sender are obtained through the 8 byte header (IP sender, port sender and msg length). Now I want to know the desination IP from the IPV4 header of the packet, is this possible? I need to detect if the UDP message was a broadcast message (IP 255.255.255.255) or an unicast message. Thanks in advance! Rob

Kei · Answer

Hi, Rob. As you already know, the UDP Header itself does not have an IP address. The IP Header has that information. Since the W7500 chip uses the H / W TOE, this information is handled at the H / W level. Among them, it uploads information that user often needs. But, Destination ip address information of received UDP packet is not provided. However, there is a way to distinguish. On the W7500, you can block Unicast, BroadCast, and Multicast through the socket settings. Refer to below link.(datasheet) [url]http://wizwiki.net/wiki/lib/exe/fetch.php?media=products:w7500:w7500_rm_v106.pdf[/url] To do this, refer to the Sn_MR Register in the Datasheet, pages 59-61. In other words, you only need to open two sockets and only non-blocking Unicast and Broadcast respectively. If you do so, you can only receive unicast packets for A sockets and broadcast packets for B sockets, so you can see what kind of cast the received packet is. I hope this helps. Best Regard, Kei.