Added initial implementation of low-level DNS packetization

and parsing functions in PJLIB-UTIL/dns.h. Errors codes
added for DNS formatting related errors.



git-svn-id: http://svn.pjsip.org/repos/pjproject/trunk@745 74dad513-b988-da41-8d7b-12977e46ad98

3 files changed, 340 insertions, 12 deletions

diff --git a/pjlib-util/include/pjlib-util.h b/pjlib-util/include/pjlib-util.h
index 33f8e0d3..741578fd 100644
--- a/pjlib-util/include/pjlib-util.h
+++ b/pjlib-util/include/pjlib-util.h
@@ -19,6 +19,7 @@
 #ifndef __PJLIB_UTIL_H__
 #define __PJLIB_UTIL_H__
 
+#include <pjlib-util/dns.h>
 #include <pjlib-util/errno.h>
 #include <pjlib-util/getopt.h>
 #include <pjlib-util/md5.h>
diff --git a/pjlib-util/include/pjlib-util/dns.h b/pjlib-util/include/pjlib-util/dns.h
new file mode 100644
index 00000000..cb6a28f2
--- /dev/null
+++ b/pjlib-util/include/pjlib-util/dns.h
@@ -0,0 +1,290 @@
+/* $Id$ */
+/* 
+ * Copyright (C) 2003-2006 Benny Prijono <benny@prijono.org>
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
+ */
+#ifndef __PJLIB_UTIL_DNS_H__
+#define __PJLIB_UTIL_DNS_H__
+
+
+/**
+ * @file dns.h
+ * @brief Asynchronous DNS Name Resolution/resolver
+ */
+#include <pj/types.h>
+
+
+PJ_BEGIN_DECL
+
+
+/**
+ * @defgroup PJ_DNS_RESOLVER Asynchronous DNS Name Resolution/resolver
+ * @ingroup PJ
+ * @{
+ *
+ * This module provides services to performing asynchronous DNS resolution.
+ */
+
+/**
+ * This enumeration describes standard DNS record types as described by
+ * RFC 1035.
+ */
+typedef enum pj_dns_type
+{
+    PJ_DNS_TYPE_A	= 1,    /**< Host address (A) record.		    */
+    PJ_DNS_TYPE_NS	= 2,    /**< Authoritative name server (NS)	    */
+    PJ_DNS_TYPE_MD	= 3,    /**< Mail destination (MD) record.	    */
+    PJ_DNS_TYPE_MF	= 4,    /**< Mail forwarder (MF) record.	    */
+    PJ_DNS_TYPE_CNAME	= 5,	/**< Canonical name (CNAME) record.	    */
+    PJ_DNS_TYPE_SOA	= 6,    /**< Marks start of zone authority.	    */
+    PJ_DNS_TYPE_MB	= 7,    /**< Mailbox domain name (MB).		    */
+    PJ_DNS_TYPE_MG	= 8,    /**< Mail group member (MG).		    */
+    PJ_DNS_TYPE_MR	= 9,    /**< Mail rename domain name.		    */
+    PJ_DNS_TYPE_NULL	= 10,	/**< NULL RR.				    */
+    PJ_DNS_TYPE_WKS	= 11,	/**< Well known service description	    */
+    PJ_DNS_TYPE_PTR	= 12,	/**< Domain name pointer.		    */
+    PJ_DNS_TYPE_HINFO	= 13,	/**< Host information.			    */
+    PJ_DNS_TYPE_MINFO	= 14,	/**< Mailbox or mail list information.	    */
+    PJ_DNS_TYPE_MX	= 15,	/**< Mail exchange record.		    */
+    PJ_DNS_TYPE_TXT	= 16,	/**< Text string.			    */
+    PJ_DNS_TYPE_RP	= 17,	/**< Responsible person.		    */
+    PJ_DNS_TYPE_AFSB	= 18,	/**< AFS cell database.			    */
+    PJ_DNS_TYPE_X25	= 19,	/**< X.25 calling address.		    */
+    PJ_DNS_TYPE_ISDN	= 20,	/**< ISDN calling address.		    */
+    PJ_DNS_TYPE_RT	= 21,	/**< Router.				    */
+    PJ_DNS_TYPE_NSAP	= 22,	/**< NSAP address.			    */
+    PJ_DNS_TYPE_NSAP_PTR= 23,	/**< NSAP reverse address.		    */
+    PJ_DNS_TYPE_SIG	= 24,	/**< Signature.				    */
+    PJ_DNS_TYPE_KEY	= 25,	/**< Key.				    */
+    PJ_DNS_TYPE_PX	= 26,	/**< X.400 mail mapping.		    */
+    PJ_DNS_TYPE_GPOS	= 27,	/**< Geographical position (withdrawn)	    */
+    PJ_DNS_TYPE_AAAA	= 28,	/**< IPv6 address.			    */
+    PJ_DNS_TYPE_LOC	= 29,	/**< Location.				    */
+    PJ_DNS_TYPE_NXT	= 30,	/**< Next valid name in the zone.	    */
+    PJ_DNS_TYPE_EID	= 31,	/**< Endpoint idenfitier.		    */
+    PJ_DNS_TYPE_NIMLOC	= 32,	/**< Nimrod locator.			    */
+    PJ_DNS_TYPE_SRV	= 33,	/**< Server selection (SRV) record.	    */
+    PJ_DNS_TYPE_ATMA	= 34,	/**< DNS ATM address record.		    */
+    PJ_DNS_TYPE_NAPTR	= 35,	/**< DNS Naming authority pointer record.   */
+    PJ_DNS_TYPE_KX	= 36,	/**< DNS key exchange record.		    */
+    PJ_DNS_TYPE_CERT	= 37,	/**< DNS certificate record.		    */
+    PJ_DNS_TYPE_A6	= 38,	/**< DNS IPv6 address (experimental)	    */
+    PJ_DNS_TYPE_DNAME	= 39,	/**< DNS non-terminal name redirection rec. */
+
+    PJ_DNS_TYPE_OPT	= 41,	/**< DNS options - contains EDNS metadata.  */
+    PJ_DNS_TYPE_APL	= 42,	/**< DNS Address Prefix List (APL) record.  */
+    PJ_DNS_TYPE_DS	= 43,	/**< DNS Delegation Signer (DS)		    */
+    PJ_DNS_TYPE_SSHFP	= 44,	/**< DNS SSH Key Fingerprint		    */
+    PJ_DNS_TYPE_IPSECKEY= 45,	/**< DNS IPSEC Key.			    */
+    PJ_DNS_TYPE_RRSIG	= 46,	/**< DNS Resource Record signature.	    */
+    PJ_DNS_TYPE_NSEC	= 47,	/**< DNS Next Secure Name.		    */
+    PJ_DNS_TYPE_DNSKEY	= 48	/**< DNSSEC Key.			    */
+} pj_dns_type;
+
+
+
+/**
+ * Standard DNS header, according to RFC 1035, which will be present in
+ * both DNS query and DNS response. 
+ *
+ * Note that all values seen by application would be in
+ * host by order. The library would convert them to network
+ * byte order as necessary.
+ */
+typedef struct pj_dns_hdr
+{
+    pj_uint16_t  id;	    /**< Transaction ID.	    */
+    pj_uint16_t  flags;	    /**< Flags.			    */
+    pj_uint16_t  qdcount;   /**< Nb. of queries.	    */
+    pj_uint16_t  anscount;  /**< Nb. of res records	    */
+    pj_uint16_t  nscount;   /**< Nb. of NS records.	    */
+    pj_uint16_t  arcount;   /**< Nb. of additional records  */
+} pj_dns_hdr;
+
+/** Create RCODE flag */
+#define PJ_DNS_SET_RCODE(c)	((pj_uint16_t)((c) & 0x0F))
+
+/** Create RA (Recursion Available) bit */
+#define PJ_DNS_SET_RA(on)	((pj_uint16_t)((on) << 7))
+
+/** Create RD (Recursion Desired) bit */
+#define PJ_DNS_SET_RD(on)	((pj_uint16_t)((on) << 8))
+
+/** Create TC (Truncated) bit */
+#define PJ_DNS_SET_TC(on)	((pj_uint16_t)((on) << 9))
+
+/** Create AA (Authoritative Answer) bit */
+#define PJ_DNS_SET_AA(on)	((pj_uint16_t)((on) << 10))
+
+/** Create four bits opcode */
+#define PJ_DNS_SET_OPCODE(o)	((pj_uint16_t)((o)  << 11))
+
+/** Create query/response bit */
+#define PJ_DNS_SET_QR(on)	((pj_uint16_t)((on) << 15))
+
+
+/** Get RCODE value */
+#define PJ_DNS_GET_RCODE(val)	(((val) & PJ_DNS_SET_RCODE(0x0F)) >> 0)
+
+/** Get RA bit */
+#define PJ_DNS_GET_RA(val)	(((val) & PJ_DNS_SET_RA(1)) >> 7)
+
+/** Get RD bit */
+#define PJ_DNS_GET_RD(val)	(((val) & PJ_DNS_SET_RD(1)) >> 8)
+
+/** Get TC bit */
+#define PJ_DNS_GET_TC(val)	(((val) & PJ_DNS_SET_TC(1)) >> 9)
+
+/** Get AA bit */
+#define PJ_DNS_GET_AA(val)	(((val) & PJ_DNS_SET_AA(1)) >> 10)
+
+/** Get OPCODE value */
+#define PJ_DNS_GET_OPCODE(val)	(((val) & PJ_DNS_SET_OPCODE(0x0F)) >> 11)
+
+/** Get QR bit */
+#define PJ_DNS_GET_QR(val)	(((val) & PJ_DNS_SET_QR(1)) >> 15)
+
+
+
+/**
+ * This constants describes record types in the DNS packet.
+ */
+typedef enum pj_dns_rec_type
+{
+    DNS_QUERY_REC,  /**< The record is a query record	    */
+    DNS_RR_REC,	    /**< The record is resource record	    */
+    DNS_NS_REC,	    /**< The record is name server record   */
+    DNS_REC_AR,	    /**< The record is additional RR.	    */
+} pj_dns_rec_type;
+
+
+/**
+ * This structure describes a Resource Record parsed from the DNS response.
+ * All integral values are in host byte order.
+ */
+typedef struct pj_dns_parsed_rr
+{
+    pj_str_t	 name;	    /**< The domain name which this rec pertains.   */
+    pj_uint16_t	 type;	    /**< RR type code.				    */
+    pj_uint16_t	 class_;    /**< Class of data (normally 1, for IN).	    */
+    pj_uint32_t	 ttl;	    /**< Time to live.				    */
+    pj_uint16_t	 rdlength;  /**< Resource data length.			    */
+    void	*data;	    /**< Pointer to the raw resource data.	    */
+    
+    /** For resource types that are recognized/supported by this library,
+     *  the parsed resource data will be placed in this rdata union.
+     */
+    union rdata
+    {
+	/** SRV Resource Data (PJ_DNS_TYPE_SRV, 33) */
+	struct srv {
+	    pj_uint16_t	prio;	/**< Target priority (lower is higher).	    */
+	    pj_uint16_t weight;	/**< Weight/proportion			    */
+	    pj_uint16_t port;	/**< Port number of the service		    */
+	    pj_str_t	target;	/**< Target name.			    */
+	} srv;
+
+	/** CNAME Resource Data (PJ_DNS_TYPE_CNAME, 5) */
+	struct cname {
+	    pj_str_t	name;	/**< Primary canonical name for an alias.   */
+	} cname;
+
+	/** NS Resource Data (PJ_DNS_TYPE_NS, 2) */
+	struct ns {
+	    pj_str_t	name;	/**< Primary name server.		    */
+	} ns;
+
+	/** PTR Resource Data (PJ_DNS_TYPE_PTR, 12) */
+	struct ptr {
+	    pj_str_t	name;	/**< PTR name.				    */
+	} ptr;
+
+	/** A Resource Data (PJ_DNS_TYPE_A, 1) */
+	struct a {
+	    pj_str_t	ip_addr;/**< IP host address string.		    */
+	} a;
+
+    } rdata;
+
+} pj_dns_parsed_rr;
+
+
+/**
+ * This structure describes the response parsed from the raw DNS response.
+ * Note that all integral values in the parsed response are represented in
+ * host byte order.
+ */
+typedef struct pj_dns_parsed_response
+{
+    pj_dns_hdr	      hdr;  /**< Pointer to DNS hdr, in host byte order */
+    pj_dns_parsed_rr *ans;  /**< Array of DNS RR answer.		*/
+    pj_dns_parsed_rr *ns;   /**< Array of NS record in the answer.	*/
+    pj_dns_parsed_rr *arr;  /**< Array of additional RR answer.		*/
+} pj_dns_parsed_response;
+
+
+/**
+ * Create DNS query packet to resolve the specified names.
+ *
+ * @param packet	The buffer to put the DNS query packet.
+ * @param size		On input, it specifies the size of the buffer.
+ *			On output, it will be filled with the actual size of
+ *			the DNS query packet.
+ * @param id		DNS query ID to associate DNS response with the
+ *			query.
+ * @param qtype		DNS type of record to be queried.
+ * @param name		Name to be queried from the DNS server.
+ *
+ * @return		PJ_SUCCESS on success, or the appropriate error code.
+ */
+PJ_DECL(pj_status_t) pj_dns_make_query(void *packet,
+				       unsigned *size,
+				       pj_uint16_t id,
+				       pj_dns_type qtype,
+				       const pj_str_t *name);
+
+/**
+ * Parse raw DNS response packet into DNS response structure.
+ *
+ * @param pool		Pool to allocate memory for the parsed response.
+ * @param packet
+ * @param size
+ * @param p_res
+ *
+ * @return		PJ_SUCCESS on success, or the appropriate error code.
+ */
+PJ_DECL(pj_status_t) pj_dns_parse_response(pj_pool_t *pool,
+					   const void *packet,
+					   unsigned size,
+					   pj_dns_parsed_response **p_res);
+
+/**
+ * Dump DNS response to standard log.
+ *
+ * @param res		The DNS response.
+ */
+PJ_DECL(void) pj_dns_dump_response(const pj_dns_parsed_response *res);
+
+
+/**
+ * @}
+ */
+
+PJ_END_DECL
+
+
+#endif	/* __PJLIB_UTIL_DNS_H__ */
+
diff --git a/pjlib-util/include/pjlib-util/errno.h b/pjlib-util/include/pjlib-util/errno.h
index 29deecfe..45e25f97 100644
--- a/pjlib-util/include/pjlib-util/errno.h
+++ b/pjlib-util/include/pjlib-util/errno.h
@@ -25,6 +25,7 @@
 
 /**
  * Start of error code relative to PJ_ERRNO_START_USER.
+ * This value is 320000.
  */
 #define PJLIB_UTIL_ERRNO_START    (PJ_ERRNO_START_USER + PJ_ERRNO_SPACE_SIZE*3)
 
@@ -36,57 +37,57 @@
  * @hideinitializer
  * Unable to resolve STUN server
  */
-#define PJLIB_UTIL_ESTUNRESOLVE	    (PJLIB_UTIL_ERRNO_START+1)
+#define PJLIB_UTIL_ESTUNRESOLVE	    (PJLIB_UTIL_ERRNO_START+1)	/* 320001 */
 /**
  * @hideinitializer
  * Unknown STUN message type.
  */
-#define PJLIB_UTIL_ESTUNINMSGTYPE   (PJLIB_UTIL_ERRNO_START+2)
+#define PJLIB_UTIL_ESTUNINMSGTYPE   (PJLIB_UTIL_ERRNO_START+2)	/* 320002 */
 /**
  * @hideinitializer
  * Invalid STUN message length.
  */
-#define PJLIB_UTIL_ESTUNINMSGLEN    (PJLIB_UTIL_ERRNO_START+3)
+#define PJLIB_UTIL_ESTUNINMSGLEN    (PJLIB_UTIL_ERRNO_START+3)	/* 320003 */
 /**
  * @hideinitializer
  * STUN attribute length error.
  */
-#define PJLIB_UTIL_ESTUNINATTRLEN   (PJLIB_UTIL_ERRNO_START+4)
+#define PJLIB_UTIL_ESTUNINATTRLEN   (PJLIB_UTIL_ERRNO_START+4)	/* 320004 */
 /**
  * @hideinitializer
  * Invalid STUN attribute type
  */
-#define PJLIB_UTIL_ESTUNINATTRTYPE  (PJLIB_UTIL_ERRNO_START+5)
+#define PJLIB_UTIL_ESTUNINATTRTYPE  (PJLIB_UTIL_ERRNO_START+5)	/* 320005 */
 /**
  * @hideinitializer
  * Invalid STUN server/socket index
  */
-#define PJLIB_UTIL_ESTUNININDEX     (PJLIB_UTIL_ERRNO_START+6)
+#define PJLIB_UTIL_ESTUNININDEX     (PJLIB_UTIL_ERRNO_START+6)	/* 320006 */
 /**
  * @hideinitializer
  * No STUN binding response in the message
  */
-#define PJLIB_UTIL_ESTUNNOBINDRES   (PJLIB_UTIL_ERRNO_START+7)
+#define PJLIB_UTIL_ESTUNNOBINDRES   (PJLIB_UTIL_ERRNO_START+7)	/* 320007 */
 /**
  * @hideinitializer
  * Received STUN error attribute
  */
-#define PJLIB_UTIL_ESTUNRECVERRATTR (PJLIB_UTIL_ERRNO_START+8)
+#define PJLIB_UTIL_ESTUNRECVERRATTR (PJLIB_UTIL_ERRNO_START+8)	/* 320008 */
 /**
  * @hideinitializer
  * No STUN mapped address attribute
  */
-#define PJLIB_UTIL_ESTUNNOMAP       (PJLIB_UTIL_ERRNO_START+9)
+#define PJLIB_UTIL_ESTUNNOMAP       (PJLIB_UTIL_ERRNO_START+9)	/* 320009 */
 /**
  * @hideinitializer
  * Received no response from STUN server
  */
-#define PJLIB_UTIL_ESTUNNOTRESPOND  (PJLIB_UTIL_ERRNO_START+10)
+#define PJLIB_UTIL_ESTUNNOTRESPOND  (PJLIB_UTIL_ERRNO_START+10)	/* 320010 */
 /**
  * @hideinitializer
  * Symetric NAT detected by STUN
  */
-#define PJLIB_UTIL_ESTUNSYMMETRIC   (PJLIB_UTIL_ERRNO_START+11)
+#define PJLIB_UTIL_ESTUNSYMMETRIC   (PJLIB_UTIL_ERRNO_START+11)	/* 320011 */
 
 
 
@@ -97,7 +98,43 @@
  * @hideinitializer
  * General invalid XML message.
  */
-#define PJLIB_UTIL_EINXML	    (PJLIB_UTIL_ERRNO_START+20)
+#define PJLIB_UTIL_EINXML	    (PJLIB_UTIL_ERRNO_START+20)	/* 320020 */
+
+
+
+/************************************************************
+ * DNS ERROR
+ ***********************************************************/
+/**
+ * @hideinitializer
+ * Outgoing DNS query packet buffer is too small.
+ * This error occurs when the user supplied buffer for creating DNS
+ * query (#pj_dns_make_query() function) is too small.
+ */
+#define PJLIB_UTIL_EDNSQRYTOOSMALL  (PJLIB_UTIL_ERRNO_START+40)	/* 320040 */
+/**
+ * @hideinitializer
+ * Invalid packet length in DNS response.
+ * This error occurs when the received DNS response packet does not
+ * match all the fields length.
+ */
+#define PJLIB_UTIL_EDNSINSIZE	    (PJLIB_UTIL_ERRNO_START+41)	/* 320041 */
+/**
+ * @hideinitializer
+ * Invalid class in DNS response.
+ * This error occurs when the received DNS response contains network
+ * class other than IN (Internet).
+ */
+#define PJLIB_UTIL_EDNSINCLASS	    (PJLIB_UTIL_ERRNO_START+42)	/* 320042 */
+/**
+ * @hideinitializer
+ * Invalid name pointer in DNS response.
+ * This error occurs when parsing the compressed names inside DNS
+ * response packet, when the name pointer points to an invalid address
+ * or the parsing has triggerred too much recursion.
+ */
+#define PJLIB_UTIL_EDNSINNAMEPTR    (PJLIB_UTIL_ERRNO_START+43)	/* 320043 */
+
 
 
 #endif	/* __PJLIB_UTIL_ERRNO_H__ */