Return first local IP address

local_ip.c

#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>

/**
 * Local IP address
 *
 * @param buf - buffer to take ip address
 * @param len - length of buffer
 */
char *local_ip( char *buf, int len )
{
	char hn[256];
	struct hostent *he;

	if( gethostname( hn, sizeof( hn ) ) )
		return NULL;

	if( !(he = gethostbyname( hn )) )
		return NULL;

	strncpy(
		buf,
		inet_ntoa( *((struct in_addr *)*he->h_addr_list) ),
		len );

	return buf;
}