域名信息查询

/*

* @brief

* Whois client program

*

* @details

* This program shall fetch whois data for a IPv4 address.

*

* @author Silver Moon ( m00n.silv3r@gmail.com )

* */

#include //scanf , printf

#include //strtok

#include //realloc

#include //socket

#include //sockaddr_in

#include //getsockname

#include //hostent

#include //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;

}

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