Results of discussion.

git-svn-id: file:///svn/unbound/trunk@231 be551aaa-1e26-0410-a405-d3ace91eadb9

doc/Changelog

@@ -1,3 +1,6 @@
+5 April 2007: Wouter
+	- discussed packed rrset with Jelte.
+
 4 April 2007: Wouter
 	- moved to version 0.3.
 	- added util/data/dname.c

doc/TODO

@@ -3,3 +3,5 @@ o use real entropy to make random (ID, port) numbers more random.
 o in production mode, do not free memory on exit. In debug mode, test leaks.
 o profile memory allocation, and if performance issues, use special memory
   allocator. For example, with caches per thread.
+o #define BIT_... different on bigendian and smallendian systems so that
+  the htons on flags is not needed to send a message from the cache.

util/data/msgreply.h

@@ -51,7 +51,11 @@ struct alloc_cache;
  * different.
  */
 struct query_info {
-	/** salient data on the query: qname, in wireformat. */
+	/** 
+	 * Salient data on the query: qname, in wireformat. 
+	 * can be allocated or a pointer to outside buffer.
+	 * User has to keep track on the status of this.
+	 */
 	uint8_t* qname;
 	/** length of qname (including last 0 octet) */
 	size_t qnamesize;
@@ -89,9 +93,17 @@ struct reply_info {
 	uint8_t* reply;
 	/** the reply size */
 	size_t replysize;
-	/** the flags for the answer, host order. */
+
+	/** the flags for the answer, host byte order. */
 	uint16_t flags;
 
+	/** 
+	 * TTL of the entire reply (for negative caching).
+	 * only for use when there are 0 RRsets in this message.
+	 * if there are RRsets, check those instead.
+	 */
+	uint32_t ttl;
+
 	/** 
 	 * network order counts: qdcount ancount nscount arcount. 
 	 * so this is wireformat for the counts as they appear in the message.
@@ -100,14 +112,17 @@ struct reply_info {
 	 */
 	uint16_t counts[4];
 
-	/** Total number of rrsets in reply: ancount+nscount+arcount. */
+	/** Total number of rrsets in reply: ancount+nscount+arcount. 
+	 * Use the accessor function to get this value.
+	 */
 	size_t num_rrsets;
 
 	/** 
 	 * List of pointers (only) to the rrsets in the order in which 
-	 * They appear in the reply message.  
+	 * they appear in the reply message.  
-	 * number of elements is ancount+nscount+arcount.
+	 * Number of elements is ancount+nscount+arcount.
-	 * this is a pointer to that array. 
+	 * This is a pointer to that array. 
+	 * Use the accessor function for access.
 	 */
 	struct packed_rrset_key** rrsets;
 
@@ -117,6 +132,15 @@ struct reply_info {
 	 * These are sorted in ascending pointer, the locking order. So
 	 * this list can be locked (and id, ttl checked), to see if 
 	 * all the data is available and recent enough.
+	 *
+	 * This is defined as an array of size 1, so that the compiler 
+	 * associates the identifier with this position in the structure.
+	 * Array bound overflow on this array then gives access to the further
+	 * elements of the array, which are allocated after the main structure.
+	 *
+	 * It could be more pure to define as array of size 0, ref[0].
+	 * But ref[1] may be less confusing for compilers.
+	 * Use the accessor function for access.
 	 */
 	struct rrset_ref ref[1];
 };

util/data/packed_rrset.h

@@ -47,6 +47,26 @@
  * clearing the cache. */
 typedef uint64_t rrset_id_t;
 
+/**
+ * The identifying information for an RRset.
+ */
+struct packed_rrset_key {
+	/**
+	 * The domain name. If not null (for id=0) it is allocated, and
+	 * contains the wireformat domain name.
+	 * This dname is not canonicalized.
+	 * After the dname uint16_t type and uint16_t class is stored 
+	 * in wireformat.
+	 * Use accessor functions to get type and class values.
+	 */
+	uint8_t* dname;
+	/** 
+	 * Length of the domain name, including last 0 root octet. 
+	 * The value+sizeof(uint16_t)*2 is actually allocated. 
+	 */
+	size_t dname_len;
+};
+
 /**
  * This structure contains an RRset. A set of resource records that
  * share the same domain name, type and class.
@@ -55,7 +75,7 @@ typedef uint64_t rrset_id_t;
  * deleted, although the data can be. The id can be set to 0 to store and the
  * structure can be recycled with a new id.
  */
-struct packed_rrset_key {
+struct ub_packed_rrset_key {
 	/** 
 	 * entry into hashtable. Note the lock is never destroyed,
 	 *  even when this key is retired to the cache. 
@@ -71,20 +91,8 @@ struct packed_rrset_key {
 	 * the id (which needs a writelock on entry.lock).
 	 */
 	rrset_id_t id;
-
+	/** key data: dname, type and class */
-	/**
+	struct packed_rrset_key rk;
-	 * The domain name. If not null (for id=0) it is allocated, and
-	 * contains the wireformat domain name.
-	 * This dname is canonicalized.
-	 * After the dname uint16_t type and uint16_t class is stored 
-	 * in wireformat.
-	 */
-	uint8_t* dname;
-	/** 
-	 * Length of the domain name, including last 0 root octet. 
-	 * The value+sizeof(uint16_t)*2 is actually allocated. 
-	 */
-	size_t dname_len;
 };
 
 /**
@@ -113,11 +121,12 @@ struct packed_rrset_key {
  *	and rr_data starts with the rdlength.
  *	the ttl value to send changes due to time.
  */
-struct packed_rrset {
+struct packed_rrset_data {
-	/** TTL (in seconds like time()) of the rrset */
+	/** TTL (in seconds like time()) of the rrset.
+	 * Same for all RRs see rfc2181(5.2).  */
 	uint32_t ttl;
 	/** number of rrs. */
-	size_t num;
+	size_t count;
 	/** 
 	 * Array of pointers to every rr's rdata. 
 	 * The rr_data[i] rdata is stored in uncompressed wireformat. 
@@ -126,12 +135,22 @@ struct packed_rrset {
 	uint8_t** rr_data;
 	/** length of every rr's rdata, rr_len[i] is size of rr_data[i]. */
 	size_t* rr_len;
-	/** TTL of every rr (equal or bigger than the rrset ttl). */
-	uint32_t* rr_ttl;
 	/** if this rrset is signed with an RRSIG, it is stored here. */
 	uint8_t* rrsig_data;
 	/** length of rrsig rdata (only examine if rrsig_data is not null) */
 	size_t rrsig_len;
 };
 
+/**
+ * An RRset can be represented using both key and data together.
+ * Split into key and data structures to simplify implementation of
+ * caching schemes.
+ */
+struct packed_rrset {
+	/** domain name, type and class */
+	struct packed_rrset_key* k;
+	/** ttl, count and rdatas (and rrsig) */
+	struct packed_rrset_data* d;
+};
+
 #endif /* UTIL_DATA_PACKED_RRSET_H */