IP-address from sk_buff

c linux-kernel netfilter
Rohit picture Rohit · Feb 25, 2009 · Viewed 14.1k times · Source

I am writing a kernel module which registers a netfilter hook. I am trying to get the ip address of the caller by using the sk_buff->saddr member. Is there a way I can get the IP in human readable i.e. x.x.x.x format?

I found the function inet_ntop() but it doesn't seem to be available in kernel headers. How do I convert \xC0\xA8\x00\x01 to 192.168.0.1 ?

Answer

Cong Wang picture Cong Wang · Nov 16, 2012

You should use the %pI4 extended format specifiers provided by printk():

printk(KERN_DEBUG "IP addres = %pI4\n", &local_ip);

Related questions

Print TCP Packet Data

In TCP Communication, when the packet is being transferred from ethernet to network(IP) layer, I want to print the data present in that packet? I am working on linux. I got some information that it can be done with …

Read More
Using sk_buff to add an Ethernet frame header

I have a kernel module that captures outgoing Internet traffic(Netfilter hook: LOCAL_OUT) At this hook, there's still no Ethernet header. I built the Ethernet header and it's ready to use, but how can I attach it to the …

Read More
Is bool a native C type?

I've noticed that the Linux kernel code uses bool, but I thought that bool was a C++ type. Is bool a standard C extension (e.g., ISO C90) or a GCC extension?

Read More