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<body class='hmmessage'><div dir='ltr'>I have a requirement to obtain the domain name from the destination IP from an outgoing packet. I am successful in capturing and obtaining the destination IP packets using the `netfilter` hook as shown below. <br><br> unsigned int hook_func_out(unsigned int hooknum, struct sk_buff * skb, const struct net_device *in, const struct net_device *out, int (*okfn)(struct sk_buff*)) <br> {<br> <br> ofs = 20; // Set theoffset to skip over the IP header.<br> <br> { <br> struct iphdr *ip_header = (struct iphdr *)skb_network_header(skb); <br> struct udphdr *udp_header; <br> struct tcphdr * tcp_header;<br> <br> //Ican obtain the destination IP address of the packet <br> //like this<br> unsigned int dest_ip = (unsigned int)ip_header->daddr;<br> <br> //or like this <br> char pkt_tbuf[16]; <br> snprintf(pkt_tbuf, 16, "%pI4", &ip_header->daddr);<br><br> //here I need to obtain the domain name of the obtained destination address<br> }<br> }<br><br>However, I have no idea on how to use that IP to obtain the domain name of the obtained IP. <br><br>I tried many sources (https://www.google.com/search?client=ubuntu&channel=fs&q=linux+kernel+programming+domain+name+from+IP+&ie=utf-8&oe=utf-8) but did find any related information on the subject and will be really grateful if you experts would provide any sample code/ references to perform this task :) <br><br>Thank you very much :)<br> </div></body>
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