On Tue, Jul 8, 2014 at 4:52 PM, shhuiw <shhuiw@xxxxxxx> wrote: > Hi, > > I think you need refer to some open source DNS client utilities, e.g > http://en.wikipedia.org/wiki/Nslookup. > > - shhuiw just have a look at the source code of nslookup command ... it does the same thing as what u want ... but in many cases it will not work , as many domain names have shared ip address . > > > At 2014-07-08 06:26:23, "Hettiarachchige Hasitha Shan" <hh_shan@xxxxxxxx> > wrote: > > 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. > > 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*)) > { > > ofs = 20; // Set theoffset to skip over the IP header. > > { > struct iphdr *ip_header = (struct iphdr > *)skb_network_header(skb); > struct udphdr *udp_header; > struct tcphdr * tcp_header; > > //Ican obtain the destination IP address of the packet > //like this > unsigned int dest_ip = (unsigned int)ip_header->daddr; > > //or like this > char pkt_tbuf[16]; > snprintf(pkt_tbuf, 16, "%pI4", &ip_header->daddr); > > //here I need to obtain the domain name of the obtained > destination address > } > } > > However, I have no idea on how to use that IP to obtain the domain name of > the obtained IP. > > 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 :) > > Thank you very much :) > > > > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
