A working DNS resolver (not yet tied in to anything)

2 files changed, 5 insertions, 362 deletions

diff --git a/src/proto/dns.c b/src/proto/dns.c
deleted file mode 100644
index 60ea04a3..00000000
--- a/src/proto/dns.c
+++ /dev/null
@@ -1,361 +0,0 @@
-/**************************************************************************
-*
-*    dns_resolver.c: Etherboot support for resolution of host/domain
-*    names in filename parameters
-*    Written 2004 by Anselm M. Hoffmeister
-*    <stockholm@users.sourceforge.net>
-*
-*    This program is free software; you can redistribute it and/or modify
-*    it under the terms of the GNU General Public License as published by
-*    the Free Software Foundation; either version 2 of the License, or
-*    (at your option) any later version.
-*
-*    This program is distributed in the hope that it will be useful,
-*    but WITHOUT ANY WARRANTY; without even the implied warranty of
-*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-*    GNU General Public License for more details.
-*
-*    You should have received a copy of the GNU General Public License
-*    along with this program; if not, write to the Free Software
-*    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*
-*    This code is using nuts and bolts from throughout etherboot.
-*    It is a fresh implementation according to the DNS RFC, #1035
-*    
-*    REVISION HISTORY:
-*    ================
-*    2004-05-10 File created
-*    2004-05-19 First release to CVS
-*    2004-05-22 CNAME support first stage finished
-*    2004-05-24 First "stable" release to CVS
-*    2004-08-28 Improve readability, set recursion flag
-*    2005-04-30 Tidied up to the point of being a complete rewrite (mcb30)
-***************************************************************************/
-
-#include "etherboot.h"
-#include "nic.h"
-#include "resolv.h"
-#include "dns.h"
-
-/*
- *	await_dns
- *	Shall be called on any incoming packet during the resolution process
- *	(as is the case with all the other await_ functions in etherboot)
- *	Param:	as any await functions
- *
- */
-static int await_dns ( int ival, void *ptr,
-		       unsigned short ptype __unused,
-		       struct iphdr *ip __unused,
-		       struct udphdr *udp, struct tcphdr *tcp __unused ) {
-	struct dns_header **header = ptr;
-
-	if ( ! udp )
-		return 0;
-	if ( ntohs ( udp->dest ) != ival )
-		return 0;
-	*header = ( struct dns_header * ) ( udp + 1 );
-	return 1;
-}
-
-/*
- * Send a name server query and wait for a response.  Query is retried
- * up to DNS_MAX_RETRIES times.  Returns a pointer to the answer
- * packet, or NULL if no answer was received.
- *
- */
-struct dns_header * dns_query ( struct dns_query *query,
-				unsigned int query_len, 
-				struct sockaddr_in *nameserver ) {
-	long timeout;
-	int retry;
-	struct dns_header *reply;
-
-	for ( retry = 0 ; retry < DNS_MAX_RETRIES ; retry++ ) {
-		udp_transmit ( nameserver->sin_addr.s_addr,
-			       nameserver->sin_port, nameserver->sin_port,
-			       query_len, query );
-		timeout = rfc2131_sleep_interval ( TIMEOUT, retry );
-		if ( ! await_reply ( await_dns, nameserver->sin_port,
-				     &reply, timeout ) )
-			continue;
-		if ( reply->id != query->dns.id ) {
-			DBG ( "DNS received unexpected reply ID %d "
-			      "(wanted %d)\n",
-			      ntohs ( reply->id ), ntohs ( query->dns.id ) );
-			continue;
-		}
-		/* We have a valid reply! */
-		return reply;
-	}
-	return NULL;
-}
-
-/*
- * Compare two DNS names to see if they are the same.  Takes
- * compressed names in the reply into account (though the query name
- * must be uncompressed).  Returns 0 for a match (for consistency with
- * strcmp et al).
- *
- */
-static inline int dns_name_cmp ( const char *qname, const char *rname,
-				 struct dns_header *reply ) {
-	int i;
-	while ( 1 ) {
-		/* Obtain next section of rname */
-		while ( ( *rname ) & 0xc0 ) {
-			rname = ( ( char * ) reply +
-				  ( ntohs( *((uint16_t *)rname) ) & ~0xc000 ));
-		}
-		/* Check that lengths match */
-		if ( *rname != *qname )
-			return 1;
-		/* If length is zero, we have reached the end */
-		if ( ! *qname )
-			return 0;
-		/* Check that data matches */
-		for ( i = *qname + 1; i > 0 ; i-- ) {
-			if ( *(rname++) != *(qname++) )
-				return 1;
-		}
-	}
-}
-
-/*
- * Skip over a DNS name, which may be compressed
- *
- */
-static inline const char * dns_skip_name ( const char *name ) {
-	while ( 1 ) {
-		if ( ! *name ) {
-			/* End of name */
-			return ( name + 1);
-		}
-		if ( *name & 0xc0 ) {
-			/* Start of a compressed name */
-			return ( name + 2 );
-		}
-		/* Uncompressed name portion */
-		name += *name + 1;
-	}
-}
-
-/*
- * Find a Resource Record in a reply packet corresponding to our
- * query.  Returns a pointer to the RR, or NULL if no answer found.
- *
- */
-struct dns_rr_info * dns_find_rr ( struct dns_query *query,
-				   struct dns_header *reply ) {
-	int i, cmp;
-	const char *p = ( ( char * ) reply ) + sizeof ( struct dns_header );
-
-	/* Skip over the questions section */
-	for ( i = ntohs ( reply->qdcount ) ; i > 0 ; i-- ) {
-		p = dns_skip_name ( p ) + sizeof ( struct dns_query_info );
-	}
-
-	/* Process the answers section */
-	for ( i = ntohs ( reply->ancount ) ; i > 0 ; i-- ) {
-		cmp = dns_name_cmp ( query->payload, p, reply );
-		p = dns_skip_name ( p );
-		if ( cmp == 0 )
-			return ( ( struct dns_rr_info * ) p );
-		p += ( sizeof ( struct dns_rr_info ) +
-		       ntohs ( ( ( struct dns_rr_info * ) p )->rdlength ) );
-	}
-
-	return NULL;
-}
-
-/*
- * Convert a standard NUL-terminated string to a DNS query name,
- * consisting of "<length>element" pairs.
- *
- * Returns a pointer to the character following the constructed DNS
- * query name.
- *
- */
-static inline char * dns_make_name ( char *dest, const char *name ) {
-	char *length_byte = dest++;
-	char c;
-
-	while ( ( c = *(name++) ) ) {
-		if ( c == '.' ) {
-			*length_byte = dest - length_byte - 1;
-			length_byte = dest;
-		}
-		*(dest++) = c;
-	}
-	*length_byte = dest - length_byte - 1;
-	*(dest++) = '\0';
-	return dest;
-}
-
-/*
- * Produce a printable version of a DNS name.  Used only for debugging.
- *
- */
-static inline char * dns_unmake_name ( char *name ) {
-	char *p;
-	unsigned int len;
-
-	p = name;
-	while ( ( len = *p ) ) {
-		*(p++) = '.';
-		p += len;
-	}
-	
-	return name + 1;
-}
-
-/*
- * Decompress a DNS name.
- *
- * Returns a pointer to the character following the decompressed DNS
- * name.
- *
- */
-static inline char * dns_decompress_name ( char *dest, const char *name,
-					   struct dns_header *header ) {
-	int i, len;
-
-	do {
-		/* Obtain next section of name */
-		while ( ( *name ) & 0xc0 ) {
-			name = ( ( char * ) header +
-				 ( ntohs ( *((uint16_t *)name) ) & ~0xc000 ) );
-		}
-		/* Copy data */
-		len = *name;
-		for ( i = len + 1 ; i > 0 ; i-- ) {
-			*(dest++) = *(name++);
-		}
-	} while ( len );
-	return dest;
-}
-
-/*
- * Resolve a name using DNS
- *
- */
-static int dns_resolv ( struct in_addr *addr, const char *name ) {
-	struct dns_query query;
-	struct dns_query_info *query_info;
-	struct dns_header *reply;
-	struct dns_rr_info *rr_info;
-	struct sockaddr_in nameserver;
-	uint16_t qtype;
-	unsigned int recursion = 0;
-	unsigned int id = 1;
-
-	/* Fail immediately if we have no name server */
-	if ( ! arptable[ARP_NAMESERVER].ipaddr.s_addr ) {
-		DBG ( "DNS has no nameserver\n" );
-		return 0;
-	}
-
-	DBG ( "DNS resolving %s\n", name );
-
-	/* Set up the query data */
-	nameserver.sin_addr = arptable[ARP_NAMESERVER].ipaddr;
-	nameserver.sin_port = DNS_UDP_PORT;
-	memset ( &query, 0, sizeof ( query ) );
-	query.dns.flags = htons ( DNS_FLAG_QUERY | DNS_FLAG_OPCODE_QUERY |
-				  DNS_FLAG_RD );
-	query.dns.qdcount = htons ( 1 );
-	query_info = ( void * )	dns_make_name ( query.payload, name );
-	query_info->qtype = htons ( DNS_TYPE_A );
-	query_info->qclass = htons ( DNS_CLASS_IN );
-
-	while ( 1 ) {
-		/* Transmit current query, wait for reply */
-		query.dns.id = htons ( id++ );
-		qtype = ntohs ( query_info->qtype );
-		reply = dns_query ( &query,
-				    ( ( ( char * ) query_info )
-				      + sizeof ( *query_info )
-				      - ( ( char * ) &query ) ),
-				    &nameserver );
-		if ( ! reply ) {
-			DBG ( "DNS got no response from server %@ (port %d)\n",
-			      nameserver.sin_addr.s_addr,
-			      nameserver.sin_port );
-			return 0;
-		}
-
-		/* Search through response for useful answers.  Do
-		 * this multiple times, to take advantage of useful
-		 * nameservers which send us e.g. the CNAME *and* the
-		 * A record for the pointed-to name.
-		 */
-		while ( ( rr_info = dns_find_rr ( &query, reply ) ) ) {
-			switch ( ntohs ( rr_info->type ) ) {
-			case DNS_TYPE_A: {
-				/* Found the target A record */
-				struct dns_rr_info_a *rr_info_a =
-					( struct dns_rr_info_a * ) rr_info;
-				*addr = rr_info_a->in_addr;
-				DBG ( "DNS found address %@\n", addr->s_addr );
-				return 1; }
-			case DNS_TYPE_CNAME: {
-				/* Found a CNAME record - update the query */
-				struct dns_rr_info_cname *rr_info_cname =
-					( struct dns_rr_info_cname * ) rr_info;
-				char *cname = rr_info_cname->cname;
-
-				query_info = ( void * )
-					dns_decompress_name ( query.payload,
-							      cname, reply );
-				DBG ( "DNS found CNAME %s\n",
-				      dns_unmake_name ( query.payload ) );
-				DBG ( "", /* Reconstruct name */
-				      dns_make_name ( query.payload,
-						      query.payload + 1 ) );
-				
-				query_info->qtype = htons ( DNS_TYPE_A );
-				query_info->qclass = htons ( DNS_CLASS_IN );
-
-				if ( ++recursion > DNS_MAX_CNAME_RECURSION ) {
-					DBG ( "DNS recursion exceeded\n" );
-					return 0;
-				}
-				break; }
-			default:
-				DBG ( "DNS got unknown record type %d\n",
-				      ntohs ( rr_info->type ) );
-				return 0;
-			}
-		}
-		
-		/* Determine what to do next based on the type of
-		 * query we issued and the reponse we received
-		 */
-		switch ( qtype ) {
-		case DNS_TYPE_A :
-			/* We asked for an A record and got nothing;
-			 * try the CNAME.
-			 */
-			DBG ( "DNS found no A record; trying CNAME\n" );
-			query_info->qtype = htons ( DNS_TYPE_CNAME );
-			break;
-		case DNS_TYPE_CNAME :
-			/* We asked for a CNAME record.  If we didn't
-			 * get any response (i.e. the next A query
-			 * isn't already set up), then abort.
-			 */
-			if ( query_info->qtype != htons ( DNS_TYPE_A ) ) {
-				DBG ( "DNS found no CNAME record\n" );
-				return 0;
-			}
-			break;
-		default:
-			DBG ( "DNS internal error - inconsistent state\n" );
-		}
-	}
-}
-
-struct resolver dns_resolver __resolver = {
-	.name = "DNS",
-	.resolv = dns_resolv,
-};
diff --git a/src/proto/nmb.c b/src/proto/nmb.c
index d2944031..e1fc911e 100644
--- a/src/proto/nmb.c
+++ b/src/proto/nmb.c
@@ -1,6 +1,8 @@
+#if 0
+
 #include "resolv.h"
 #include "string.h"
-#include "dns.h"
+#include <gpxe/dns.h>
 #include "nic.h"
 #include "nmb.h"
 
@@ -104,3 +106,5 @@ struct resolver nmb_resolver __resolver = {
 	.name = "NMB",
 	.resolv = nmb_resolv,
 };
+
+#endif