2005-05-01 13:10:17 +02:00
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#include "resolv.h"
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#include "string.h"
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#include "dns.h"
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#include "nic.h"
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#include "nmb.h"
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/*
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* Convert a standard NUL-terminated string to an NBNS query name.
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*
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* Returns a pointer to the character following the constructed NBNS
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* query name.
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*
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*/
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static inline char * nbns_make_name ( char *dest, const char *name ) {
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char nb_name[16];
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char c;
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int i;
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2005-05-24 01:47:54 +02:00
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uint16_t *d;
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2005-05-01 13:10:17 +02:00
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*(dest++) = 32; /* Length is always 32 */
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/* Name encoding is as follows: pad the name with spaces to
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* length 15, and add a NUL. Take this 16-byte string, split
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* it into nibbles and add 0x41 to each nibble to form a byte
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* of the resulting name string.
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*/
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memset ( nb_name, ' ', 15 );
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nb_name[15] = '\0';
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memcpy ( nb_name, name, strlen ( name ) ); /* Do not copy NUL */
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2005-05-24 01:47:54 +02:00
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d = ( uint16_t * ) dest;
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2005-05-01 13:10:17 +02:00
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for ( i = 0 ; i < 16 ; i++ ) {
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c = nb_name[i];
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2005-05-24 01:47:54 +02:00
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*( d++ ) = htons ( ( ( c | ( c << 4 ) ) & 0x0f0f ) + 0x4141 );
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2005-05-01 13:10:17 +02:00
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}
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2005-05-24 01:47:54 +02:00
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dest = ( char * ) d;
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2005-05-01 13:10:17 +02:00
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*(dest++) = 0; /* Terminating 0-length name component */
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return dest;
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}
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/*
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* Resolve a name using NMB
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*
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*/
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static int nmb_resolv ( struct in_addr *addr, const char *name ) {
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struct dns_query query;
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struct dns_query_info *query_info;
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struct dns_header *reply;
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struct dns_rr_info *rr_info;
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struct dns_rr_info_nb *rr_info_nb;
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struct sockaddr_in nameserver;
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DBG ( "NMB resolving %s\n", name );
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/* Set up the query data */
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2006-04-24 17:42:49 +02:00
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nameserver.sin_addr.s_addr = INADDR_BROADCAST;
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2005-05-01 13:10:17 +02:00
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nameserver.sin_port = NBNS_UDP_PORT;
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memset ( &query, 0, sizeof ( query ) );
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query.dns.id = htons ( 1 );
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query.dns.flags = htons ( DNS_FLAG_QUERY | DNS_FLAG_OPCODE_QUERY |
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DNS_FLAG_RD | DNS_FLAG_BROADCAST );
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query.dns.qdcount = htons ( 1 );
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query_info = ( void * ) nbns_make_name ( query.payload, name );
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query_info->qtype = htons ( DNS_TYPE_NB );
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query_info->qclass = htons ( DNS_CLASS_IN );
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/* Issue query, wait for reply */
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reply = dns_query ( &query,
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( ( ( char * ) query_info )
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+ sizeof ( *query_info )
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- ( ( char * ) &query ) ),
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&nameserver );
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if ( ! reply ) {
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DBG ( "NMB got no response via %@ (port %d)\n",
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nameserver.sin_addr.s_addr,
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nameserver.sin_port );
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return 0;
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}
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/* Search through response for useful answers. */
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rr_info = dns_find_rr ( &query, reply );
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if ( ! rr_info ) {
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DBG ( "NMB got invalid response\n" );
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return 0;
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}
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/* Check type of response */
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if ( ntohs ( rr_info->type ) != DNS_TYPE_NB ) {
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DBG ( "NMB got answer type %hx (wanted %hx)\n",
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ntohs ( rr_info->type ), DNS_TYPE_NB );
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return 0;
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}
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/* Read response */
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rr_info_nb = ( struct dns_rr_info_nb * ) rr_info;
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*addr = rr_info_nb->nb_address;
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DBG ( "NMB found address %@\n", addr->s_addr );
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return 1;
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}
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2006-04-24 20:31:37 +02:00
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struct resolver nmb_resolver __resolver = {
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2005-05-01 13:10:17 +02:00
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.name = "NMB",
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.resolv = nmb_resolv,
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};
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