Re: How do we determine IP Address of interface the packet arrived on

On Wed, Sep 24, 2014 at 10:19:34AM +0530, Maninder Singh wrote:

Hi,

Each time a packet arrives at a router in a subnet during transit, I need to determine the IP address of the incoming interface of the router for that packet. I have a netfilter kernel module running at each router but I dont understand which data structure will give me thw IP address. Can someone please suggest how shall I get that?

An interface can have more than one IP address, so your question is a little strange. However, you can find out all the IPv4 addresses a particular device has by iterating through dev->ip_ptr->ifa_list. Hope this helps, Vlad