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

src/include/errno.h

@@ -137,6 +137,7 @@
 #define EINVAL		0xdd	/**< Invalid argument */
 #define EIO		0xde	/**< Input/output error */
 #define EISCONN		0xdf	/**< Transport endpoint is already connected */
+#define ELOOP		0xf8	/**< Too many symbolic links */
 #define EMFILE		0xe0	/**< Too many open files */
 #define EMSGSIZE	0xe1	/**< Message too long */
 #define ENAMETOOLONG	0xe2	/**< File name too long */

src/include/dns.h → src/include/gpxe/dns.h

@@ -1,10 +1,16 @@
-#ifndef DNS_RESOLVER_H
-#define DNS_RESOLVER_H
+#ifndef _GPXE_DNS_H
+#define _GPXE_DNS_H
 
-#include "stdint.h"
+/** @file
+ *
+ * DNS protocol
+ *
+ */
+
+#include <stdint.h>
 #include <gpxe/in.h>
-#include "ip.h"
-#include "udp.h"
+#include <gpxe/async.h>
+#include <gpxe/retry.h>
 
 /*
  * Constants
@@ -33,7 +39,7 @@
 #define DNS_FLAG_RCODE_NX	( 0x03 << 0 )
 #define DNS_FLAG_RCODE(flags)	( (flags) & ( 0x0f << 0 ) )
 
-#define	DNS_UDP_PORT		53
+#define	DNS_PORT		53
 #define	DNS_MAX_RETRIES		3
 #define	DNS_MAX_CNAME_RECURSION	0x30
 
@@ -56,13 +62,11 @@ struct dns_query_info {
 } __attribute__ (( packed ));
 
 struct dns_query {
-	struct iphdr	ip;
-	struct udphdr	udp;
 	struct dns_header dns;
 	char		payload[ 256 + sizeof ( struct dns_query_info ) ];
 } __attribute__ (( packed ));
 
-struct dns_rr_info {
+struct dns_rr_info_common {
 	uint16_t	type;
 	uint16_t	class;
 	uint32_t	ttl;
@@ -70,23 +74,36 @@ struct dns_rr_info {
 } __attribute__ (( packed ));
 
 struct dns_rr_info_a {
-	struct dns_rr_info info;
+	struct dns_rr_info_common common;
 	struct in_addr in_addr;
 } __attribute__ (( packed ));
 
 struct dns_rr_info_cname {
-	struct dns_rr_info info;
-	char		cname[0];
+	struct dns_rr_info_common common;
+	char cname[0];
 } __attribute__ (( packed ));
 
-/*
- * Functions in dns.c (used by nmb.c)
- *
- */
-extern struct dns_header * dns_query ( struct dns_query *query,
-				       unsigned int query_len, 
-				       struct sockaddr_in *nameserver );
-extern struct dns_rr_info * dns_find_rr ( struct dns_query *query,
-					  struct dns_header *reply );
+union dns_rr_info {
+	struct dns_rr_info_common common;
+	struct dns_rr_info_a a;
+	struct dns_rr_info_cname cname;
+};
+
+struct dns_request {
+
+	struct sockaddr_tcpip *st;
+
+	struct async async;
+	struct dns_query query;
+	struct dns_query_info *qinfo;
+
+	unsigned int recursion;
+
+	struct udp_connection udp;
+	struct retry_timer timer;
+};
+
+extern int dns_resolv ( const char *name, struct sockaddr_tcpip *st,
+			struct async *parent );
 
-#endif /* DNS_RESOLVER_H */
+#endif /* _GPXE_DNS_H */

src/include/nmb.h

@@ -1,7 +1,7 @@
 #ifndef NMB_H
 #define NMB_H
 
-#include "dns.h"
+#include <gpxe/dns.h>
 
 /*
  * NetBIOS name query packets are basically the same as DNS packets,

src/net/udp/dns.c

@@ -0,0 +1,463 @@
+/*
+ * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * Portions copyright (C) 2004 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 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.
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <byteswap.h>
+#include <gpxe/async.h>
+#include <gpxe/udp.h>
+#include <gpxe/dhcp.h>
+#include <gpxe/dns.h>
+
+/** @file
+ *
+ * DNS protocol
+ *
+ */
+
+/**
+ * Compare DNS reply name against the query name from the original request
+ *
+ * @v dns		DNS request
+ * @v reply		DNS reply
+ * @v rname		Reply name
+ * @ret	zero		Names match
+ * @ret non-zero	Names do not match
+ */
+static int dns_name_cmp ( struct dns_request *dns, struct dns_header *reply, 
+			  const char *rname ) {
+	const char *qname = dns->query.payload;
+	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 (possibly compressed) DNS name
+ *
+ * @v name		DNS name
+ * @ret name		Next DNS name
+ */
+static 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 an RR in a reply packet corresponding to our query
+ *
+ * @v dns		DNS request
+ * @v reply		DNS reply
+ * @ret rr		DNS RR, or NULL if not found
+ */
+static union dns_rr_info * dns_find_rr ( struct dns_request *dns,
+					 struct dns_header *reply ) {
+	int i, cmp;
+	const char *p = ( ( char * ) reply ) + sizeof ( struct dns_header );
+	union dns_rr_info *rr_info;
+
+	/* 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 ( dns, reply, p );
+		p = dns_skip_name ( p );
+		rr_info = ( ( union dns_rr_info * ) p );
+		if ( cmp == 0 )
+			return rr_info;
+		p += ( sizeof ( rr_info->common ) +
+		       ntohs ( rr_info->common.rdlength ) );
+	}
+
+	return NULL;
+}
+
+/**
+ * Convert a standard NUL-terminated string to a DNS name
+ *
+ * @v string		Name as a NUL-terminated string
+ * @v buf		Buffer in which to place DNS name
+ * @ret next		Byte following constructed DNS name
+ *
+ * DNS names consist of "<length>element" pairs.
+ */
+static char * dns_make_name ( const char *string, char *buf ) {
+	char *length_byte = buf++;
+	char c;
+
+	while ( ( c = *(string++) ) ) {
+		if ( c == '.' ) {
+			*length_byte = buf - length_byte - 1;
+			length_byte = buf;
+		}
+		*(buf++) = c;
+	}
+	*length_byte = buf - length_byte - 1;
+	*(buf++) = '\0';
+	return buf;
+}
+
+/**
+ * Convert an uncompressed DNS name to a NUL-terminated string
+ *
+ * @v name		DNS name
+ * @ret string		NUL-terminated string
+ *
+ * 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
+ *
+ * @v reply		DNS replay
+ * @v name		DNS name
+ * @v buf		Buffer into which to decompress DNS name
+ * @ret next		Byte following decompressed DNS name
+ */
+static char * dns_decompress_name ( struct dns_header *reply,
+				    const char *name, char *buf ) {
+	int i, len;
+
+	do {
+		/* Obtain next section of name */
+		while ( ( *name ) & 0xc0 ) {
+			name = ( ( char * ) reply +
+				 ( ntohs ( *((uint16_t *)name) ) & ~0xc000 ) );
+		}
+		/* Copy data */
+		len = *name;
+		for ( i = len + 1 ; i > 0 ; i-- ) {
+			*(buf++) = *(name++);
+		}
+	} while ( len );
+	return buf;
+}
+
+/**
+ * Mark DNS request as complete
+ *
+ * @v dns		DNS request
+ * @v rc		Return status code
+ */
+static void dns_done ( struct dns_request *dns, int rc ) {
+
+	/* Stop the retry timer */
+	stop_timer ( &dns->timer );
+
+	/* Close UDP connection */
+	udp_close ( &dns->udp );
+
+	/* Mark async operation as complete */
+	async_done ( &dns->async, rc );
+}
+
+/**
+ * Send next packet in DNS request
+ *
+ * @v dns		DNS request
+ */
+static void dns_send_packet ( struct dns_request *dns ) {
+	static unsigned int qid = 0;
+
+	/* Increment query ID */
+	dns->query.dns.id = htons ( ++qid );
+
+	DBGC ( dns, "DNS %p sending query ID %d\n", dns, qid );
+
+	/* Start retransmission timer */
+	start_timer ( &dns->timer );
+
+	/* Send the data */
+	udp_send ( &dns->udp, &dns->query,
+		   ( ( ( void * ) dns->qinfo ) - ( ( void * ) &dns->query )
+		     + sizeof ( dns->qinfo ) ) );
+}
+
+/**
+ * Handle DNS retransmission timer expiry
+ *
+ * @v timer		Retry timer
+ * @v fail		Failure indicator
+ */
+static void dns_timer_expired ( struct retry_timer *timer, int fail ) {
+	struct dns_request *dns =
+		container_of ( timer, struct dns_request, timer );
+
+	if ( fail ) {
+		dns_done ( dns, -ETIMEDOUT );
+	} else {
+		dns_send_packet ( dns );
+	}
+}
+
+/**
+ * Receive new data
+ *
+ * @v udp		UDP connection
+ * @v data		Received data
+ * @v len		Length of received data
+ * @v st_src		Partially-filled source address
+ * @v st_dest		Partially-filled destination address
+ */
+static int dns_newdata ( struct udp_connection *conn, void *data, size_t len,
+			 struct sockaddr_tcpip *st_src __unused,
+			 struct sockaddr_tcpip *st_dest __unused ) {
+	struct dns_request *dns =
+		container_of ( conn, struct dns_request, udp );
+	struct dns_header *reply = data;
+	union dns_rr_info *rr_info;
+	struct sockaddr_in *sin;
+	unsigned int qtype = dns->qinfo->qtype;
+
+	/* Sanity check */
+	if ( len < sizeof ( *reply ) ) {
+		DBGC ( dns, "DNS %p received underlength packet length %zd\n",
+		       dns, len );
+		return -EINVAL;
+	}
+
+	/* Check reply ID matches query ID */
+	if ( reply->id != dns->query.dns.id ) {
+		DBGC ( dns, "DNS %p received unexpected reply ID %d "
+		       "(wanted %d)\n", dns, ntohs ( reply->id ),
+		       ntohs ( dns->query.dns.id ) );
+		return -EINVAL;
+	}
+
+	DBGC ( dns, "DNS %p received reply ID %d\n", dns, ntohs ( reply->id ));
+
+	/* Stop the retry timer.  After this point, each code path
+	 * must either restart the timer by calling dns_send_packet(),
+	 * or mark the DNS operation as complete by calling
+	 * dns_done()
+	 */
+	stop_timer ( &dns->timer );
+
+	/* 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 ( dns, reply ) ) ) {
+		switch ( rr_info->common.type ) {
+
+		case htons ( DNS_TYPE_A ):
+
+			/* Found the target A record */
+			DBGC ( dns, "DNS %p found address %s\n",
+			       dns, inet_ntoa ( rr_info->a.in_addr ) );
+			sin = ( struct sockaddr_in * ) dns->st;
+			sin->sin_family = AF_INET;
+			sin->sin_addr = rr_info->a.in_addr;
+
+			/* Mark operation as complete */
+			dns_done ( dns, 0 );
+			return 0;
+
+		case htons ( DNS_TYPE_CNAME ):
+
+			/* Found a CNAME record; update query and recurse */
+			DBGC ( dns, "DNS %p found CNAME\n", dns );
+			dns->qinfo = ( void * ) dns_decompress_name ( reply,
+							 rr_info->cname.cname,
+							 dns->query.payload );
+			dns->qinfo->qtype = htons ( DNS_TYPE_A );
+			dns->qinfo->qclass = htons ( DNS_CLASS_IN );
+			
+			/* Terminate the operation if we recurse too far */
+			if ( ++dns->recursion > DNS_MAX_CNAME_RECURSION ) {
+				DBGC ( dns, "DNS %p recursion exceeded\n",
+				       dns );
+				dns_done ( dns, -ELOOP );
+				return 0;
+			}
+			break;
+
+		default:
+			DBGC ( dns, "DNS %p got unknown record type %d\n",
+			       dns, ntohs ( rr_info->common.type ) );
+			break;
+		}
+	}
+	
+	/* Determine what to do next based on the type of query we
+	 * issued and the reponse we received
+	 */
+	switch ( qtype ) {
+
+	case htons ( DNS_TYPE_A ):
+		/* We asked for an A record and got nothing;
+		 * try the CNAME.
+		 */
+		DBGC ( dns, "DNS %p found no A record; trying CNAME\n", dns );
+		dns->qinfo->qtype = htons ( DNS_TYPE_CNAME );
+		dns_send_packet ( dns );
+		return 0;
+
+	case htons ( DNS_TYPE_CNAME ):
+		/* We asked for a CNAME record.  If we got a response
+		 * (i.e. if the next A query is already set up), then
+		 * issue it, otherwise abort.
+		 */
+		if ( dns->qinfo->qtype == htons ( DNS_TYPE_A ) ) {
+			dns_send_packet ( dns );
+			return 0;
+		} else {
+			DBGC ( dns, "DNS %p found no CNAME record\n", dns );
+			dns_done ( dns, -ENXIO );
+			return 0;
+		}
+
+	default:
+		assert ( 0 );
+		dns_done ( dns, -EINVAL );
+		return 0;
+	}
+}
+
+/** DNS UDP operations */
+struct udp_operations dns_udp_operations = {
+	.newdata = dns_newdata,
+};
+
+/**
+ * Reap asynchronous operation
+ *
+ * @v async		Asynchronous operation
+ */
+static void dns_reap ( struct async *async ) {
+	struct dns_request *dns =
+		container_of ( async, struct dns_request, async );
+
+	free ( dns );
+}
+
+/** DNS asynchronous operations */
+static struct async_operations dns_async_operations = {
+	.reap = dns_reap,
+};
+
+/**
+ * Resolve name using DNS
+ *
+ */
+int dns_resolv ( const char *name, struct sockaddr_tcpip *st,
+		 struct async *parent ) {
+	struct dns_request *dns;
+	union {
+		struct sockaddr_tcpip st;
+		struct sockaddr_in sin;
+	} nameserver;
+	int rc;
+
+	/* Allocate DNS structure */
+	dns = malloc ( sizeof ( *dns ) );
+	if ( ! dns ) {
+		rc = -ENOMEM;
+		goto err;
+	}
+	memset ( dns, 0, sizeof ( *dns ) );
+	dns->st = st;
+	dns->timer.expired = dns_timer_expired;
+	dns->udp.udp_op = &dns_udp_operations;
+
+	/* Create query */
+	dns->query.dns.flags = htons ( DNS_FLAG_QUERY | DNS_FLAG_OPCODE_QUERY |
+				       DNS_FLAG_RD );
+	dns->query.dns.qdcount = htons ( 1 );
+	dns->qinfo = ( void * ) dns_make_name ( name, dns->query.payload );
+	dns->qinfo->qtype = htons ( DNS_TYPE_A );
+	dns->qinfo->qclass = htons ( DNS_CLASS_IN );
+
+	/* Open UDP connection */
+	memset ( &nameserver, 0, sizeof ( nameserver ) );
+	nameserver.sin.sin_family = AF_INET;
+	nameserver.sin.sin_port = htons ( DNS_PORT );
+#warning "DHCP-DNS hack"
+	struct dhcp_option *option =
+		find_global_dhcp_option ( DHCP_DNS_SERVERS );
+	if ( ! option ) {
+		DBGC ( dns, "DNS %p no name servers\n", dns );
+		rc = -ENXIO;
+		goto err;
+	}
+	dhcp_ipv4_option ( option, &nameserver.sin.sin_addr );
+	DBGC ( dns, "DNS %p using nameserver %s\n", dns, 
+	       inet_ntoa ( nameserver.sin.sin_addr ) );
+	udp_connect ( &dns->udp, &nameserver.st );
+	if ( ( rc = udp_open ( &dns->udp, 0 ) ) != 0 )
+		goto err;
+
+	dns_send_packet ( dns );
+
+	async_init ( &dns->async, &dns_async_operations, parent );
+	return 0;	
+
+ err:
+	DBGC ( dns, "DNS %p could not create request: %s\n", 
+	       dns, strerror ( rc ) );
+	free ( dns );
+	return rc;
+}

src/proto/dns.c

@@ -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,
-};

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