Convert source IP address from struct iphdr* to string equivalent using Linux netfilter

I want to convert the source & destination IP addresses from a packet captured using netfilter to char *.

In my netfilter hook function, I have:

sock_buff = skb; // argument 2 of hook function

// ip_header is struct iphdr*
ip_header = (struct iphdr *)skb_network_header(sock_buff);

// now how to convert ip_header->saddr & ip_header->daddr to char *
// ip_header->saddr & ip_header->daddr are of type __be32

Thanks.