http://www.binarytides.com/c-code-to-perform-ip-whois/
http://www.oschina.net/code/snippet_12_9390
/*
* @brief
* Whois client program
*
* @details
* This program shall fetch whois data for a IPv4 address.
*
* @author Silver Moon ( [email protected] )
* */
#include<stdio.h> //scanf , printf
#include<string.h> //strtok
#include<stdlib.h> //realloc
#include<sys/socket.h> //socket
#include<netinet/in.h> //sockaddr_in
#include<arpa/inet.h> //getsockname
#include<netdb.h> //hostent
#include<unistd.h> //close
int
main(
int
argc ,
char
*argv[])
{
char
ip[100] , *data = NULL;
printf
(
"Enter ip address to whois : "
);
scanf
(
"%s"
, ip);
get_whois(ip , &data);
printf
(
"\n\n"
);
puts
(data);
free
(data);
return
0;
}
/**
Get the whois content of an ip
by selecting the correct server
*/
void
get_whois(
char
*ip ,
char
**data)
{
char
*wch = NULL, *pch , *response = NULL;
if
(whois_query(
"whois.iana.org"
, ip , &response))
{
printf
(
"Whois query failed"
);
}
pch =
strtok
(response ,
"\n"
);
while
(pch != NULL)
{
//Check if whois line
wch =
strstr
(pch ,
"whois."
);
if
(wch != NULL)
{
break
;
}
//Next line please
pch =
strtok
(NULL ,
"\n"
);
}
if
(wch != NULL)
{
printf
(
"\nWhois server is : %s"
, wch);
whois_query(wch , ip , data);
}
else
{
*data =
malloc
(100);
strcpy
(*data ,
"No whois data"
);
}
return
;
}
/*
* Perform a whois query to a server and record the response
* */
int
whois_query(
char
*server ,
char
*query ,
char
**response)
{
char
ip[32] , message[100] , buffer[1500];
int
sock , read_size , total_size = 0;
struct
sockaddr_in dest;
sock = socket(AF_INET , SOCK_STREAM , IPPROTO_TCP);
//Prepare connection structures :)
memset
( &dest , 0 ,
sizeof
(dest) );
dest.sin_family = AF_INET;
printf
(
"\nResolving %s..."
, server);
if
(hostname_to_ip(server , ip))
{
printf
(
"Failed"
);
return
1;
}
printf
(
"%s"
, ip);
dest.sin_addr.s_addr = inet_addr( ip );
dest.sin_port = htons( 43 );
//Now connect to remote server
if
(connect( sock , (
const
struct
sockaddr*) &dest ,
sizeof
(dest) ) < 0)
{
perror
(
"connect failed"
);
}
//Now send some data or message
printf
(
"\nQuerying for ... %s ..."
, query);
sprintf
(message ,
"%s\r\n"
, query);
if
( send(sock , message ,
strlen
(message) , 0) < 0)
{
perror
(
"send failed"
);
}
//Now receive the response
while
( (read_size = recv(sock , buffer ,
sizeof
(buffer) , 0) ) )
{
*response =
realloc
(*response , read_size + total_size);
if
(*response == NULL)
{
printf
(
"realloc failed"
);
}
memcpy
(*response + total_size , buffer , read_size);
total_size += read_size;
}
printf
(
"Done"
);
fflush
(stdout);
*response =
realloc
(*response , total_size + 1);
*(*response + total_size) =
'\0'
;
close(sock);
return
0;
}
/*
* @brief
* Get the ip address of a given hostname
*
* */
int
hostname_to_ip(
char
* hostname ,
char
* ip)
{
struct
hostent *he;
struct
in_addr **addr_list;
int
i;
if
( (he = gethostbyname( hostname ) ) == NULL)
{
// get the host info
herror(
"gethostbyname"
);
return
1;
}
addr_list = (
struct
in_addr **) he->h_addr_list;
for
(i = 0; addr_list[i] != NULL; i++)
{
//Return the first one;
strcpy
(ip , inet_ntoa(*addr_list[i]) );
return
0;
}
return
0;
}