snapshot work

lib/dns/include/dns/message.h

@@ -66,26 +66,28 @@ ISC_LANG_BEGINDECLS
 #define DNS_MESSAGE_OPCODE_SHIFT	    11
 #define DNS_MESSAGE_RCODE_MASK		0x000fU
 
+/*
+ * Ordering here matters.  DNS_SECTION_ANY must be the lowest and negative,
+ * and DNS_SECTION_MAX must be one greater than the last used section.
+ */
 typedef int dns_section_t;
-#define DNS_SECTION_ANY			(-1) /* XXX good idea? */
+#define DNS_SECTION_ANY			(-1)
 #define DNS_SECTION_QUESTION		0
 #define DNS_SECTION_ANSWER		1
 #define DNS_SECTION_AUTHORITY		2
 #define DNS_SECTION_ADDITIONAL		3
 #define DNS_SECTION_OPT			4 /* pseudo-section */
 #define DNS_SECTION_TSIG		5 /* pseudo-section */
+#define DNS_SECTION_MAX			6
 
 /*
- * "helper" type, which consists of a block of some type, and is linkable.
- * For it to work, sizeof(dns_msgblock_t) must be a multiple of the pointer
- * size, or the allocated elements will not be alligned correctly.
+ * These tell the message library how the created dns_message_t will be used.
  */
+#define DNS_MESSAGE_INTENT_UNKNOWN	0 /* internal use only */
+#define DNS_MESSAGE_INTENT_PARSE	1 /* parsing messages */
+#define DNS_MESSAGE_INTENT_RENDER	2 /* rendering */
+
 typedef struct dns_msgblock dns_msgblock_t;
-struct dns_msgblock {
-	unsigned int			length;
-	unsigned int			remaining;
-	ISC_LINK(dns_msgblock_t)	link;
-}; /* dynamically sized */
 
 typedef struct {
 	unsigned int			magic;
@@ -101,26 +103,23 @@ typedef struct {
 	unsigned int			aucount;
 	unsigned int			adcount;
 
-	dns_namelist_t			question;
-	dns_namelist_t			answer;
-	dns_namelist_t			authority;
-	dns_namelist_t			additional;
+	/* 4 real, 2 pseudo */
+	dns_namelist_t			sections[DNS_SECTION_MAX];
+	dns_name_t		       *cursors[DNS_SECTION_MAX];
 
-	unsigned int			handled_question : 1;
-	unsigned int			handled_answer : 1;
-	unsigned int			handled_authority : 1;
-	unsigned int			handled_additional : 1;
+	int				state;
 	unsigned int			from_to_wire : 2;
+	unsigned int			reserved;
 
 	isc_mem_t		       *mctx;
-	isc_dynbuffer_t		       *scratchpad;
+	ISC_LIST(isc_dynbuffer_t)	scratchpad;
 	ISC_LIST(dns_msgblock_t)	names;
 	ISC_LIST(dns_msgblock_t)	rdatas;
 	ISC_LIST(dns_msgblock_t)	rdatalists;
 } dns_message_t;
 
 dns_result_t
-dns_message_init(isc_mem_t *mctx, dns_message_t *msg);
+dns_message_create(isc_mem_t *mctx, dns_message_t **msg, unsigned int intent);
 /*
  * Initialize msg structure.  Must be called on a new (or reused) structure.
  *
@@ -130,14 +129,15 @@ dns_message_init(isc_mem_t *mctx, dns_message_t *msg);
  * Requires:
  *	'mctx' be a valid memory context.
  *
- *	'msg' be invalid.
+ *	'msg' be non-null and '*msg' be NULL.
+ *
+ *	'intent' must be one of DNS_MESSAGE_INTENT_PARSE or
+ *	DNS_MESSAGE_INTENT_RENDER.
  *
  * Ensures:
- *	The data in "msg" is set to indicate an unused and empty msg
+ *	The data in "*msg" is set to indicate an unused and empty msg
  *	structure.
  *
- *	Some bit of internal scratchpad memory is allocated.
- *
  * Returns:
  *	DNS_R_NOMEMORY		- out of memory
  *	DNS_R_SUCCESS		- success
@@ -160,7 +160,7 @@ dns_message_reset(dns_message_t *msg);
  */
 
 void
-dns_message_destroy(dns_message_t *msg);
+dns_message_destroy(dns_message_t **msg);
 /*
  * Destroy all state in the message.
  *
@@ -221,7 +221,7 @@ dns_message_renderbegin(dns_message_t *msg, isc_buffer_t *buffer);
 
 dns_result_t
 dns_message_renderreserve(dns_message_t *msg, isc_buffer_t *buffer,
-			  int space);
+			  unsigned int space);
 /*
  * Reserve "space" bytes in the given buffer.
  *
@@ -235,6 +235,21 @@ dns_message_renderreserve(dns_message_t *msg, isc_buffer_t *buffer,
  *	DNS_R_NOSPACE		-- not enough free space in the buffer.
  */
 
+dns_result_t
+dns_message_renderrelease(dns_message_t *msg, unsigned int space);
+/*
+ * Release "space" bytes in the given buffer that was previously reserved.
+ *
+ * Requires:
+ *
+ *	'msg' be valid.
+ *
+ * Returns:
+ *
+ *	DNS_R_SUCCESS		-- all is well.
+ *	DNS_R_NOSPACE		-- trying to release more than was reserved.
+ */
+
 dns_result_t
 dns_message_rendersection(dns_message_t *msg, isc_buffer_t *buffer,
 			  dns_section_t section, unsigned int priority,
@@ -306,13 +321,16 @@ dns_message_nextname(dns_message_t *msg, dns_section_t section);
  *
  *	'section' be a valid section.
  *
+ *	dns_message_firstname() must have been called on this section,
+ *	and the result was DNS_R_SUCCESS.
+ *
  * Returns:
  *
  *	DNS_R_SUCCESS		-- All is well.
  *	DNS_R_NOMORE		-- No names in given section.
  */
 
-dns_result_t
+void
 dns_message_currentname(dns_message_t *msg, dns_section_t section,
 			dns_name_t **name);
 /*
@@ -327,10 +345,9 @@ dns_message_currentname(dns_message_t *msg, dns_section_t section,
  *
  *	'section' be a valid section.
  *
- * Returns:
- *
- *	DNS_R_SUCCESS		-- All is well.
- *	DNS_R_NOMORE		-- No names in given section.
+ *	dns_message_firstname() must have been called on this section,
+ *	and the result of it and any dns_message_nextname() calls was
+ *	DNS_R_SUCCESS.
  */
 
 dns_result_t
@@ -377,21 +394,31 @@ dns_message_movename(dns_message_t *msg, dns_name_t *name,
  *
  *	'msg' be valid.
  *
- *	'name' must be a member of the section it is to be moved from.
+ *	'name' must be in 'fromsection'.
  *
  *	'fromsection' must be a valid section.
  *
  *	'tosection' must be a valid section, and be renderable.
+ *
+ *	'fromsection' and 'tosection' cannot be the same section.
  */
 
-dns_result_t
-dns_message_addname(dns_message_t *msg, dns_section_t section,
-		    dns_name_t *name);
+void
+dns_message_addname(dns_message_t *msg, dns_name_t *name,
+		    dns_section_t section);
 /*
  * Adds the name to the given section.
  *
  * Caller must ensure that the name does not already exist.  This condition
  * is NOT checked for by this function.
+ *
+ * Requires:
+ *
+ *	'msg' be valid, and be a renderable message.
+ *
+ *	'name' be a valid name.
+ *
+ *	'section' be a named section.
  */
 
 ISC_LANG_ENDDECLS

lib/dns/message.c

@@ -25,31 +25,73 @@
 #include <string.h>
 
 #include <isc/assertions.h>
+#include <isc/boolean.h>
+#include <isc/region.h>
 
 #include <dns/message.h>
 #include <dns/rdataset.h>
+#include <dns/rdata.h>
+#include <dns/rdataclass.h>
+#include <dns/rdatatype.h>
+#include <dns/rdatalist.h>
+#include <dns/compress.h>
 
 #define MESSAGE_MAGIC		0x4d534740U	/* MSG@ */
-#define VALID_MESSAGE_MAGIC(magic)  ((magic) == MESSAGE_MAGIC)
+#define VALID_MESSAGE(msg)	(((msg)->magic) == MESSAGE_MAGIC)
+
+#define VALID_NAMED_SECTION(s)  (((s) > DNS_SECTION_ANY) \
+				 && ((s) < DNS_SECTION_MAX))
+#define VALID_SECTION(s)	(((s) >= DNS_SECTION_ANY) \
+				 && ((s) < DNS_SECTION_MAX))
+
+/*
+ * This is the size of each individual scratchpad buffer, and the numbers
+ * of various block allocations used within the server.
+ */
+#define SCRATCHPAD_SIZE		768
+#define NAME_COUNT		 16
+#define RDATA_COUNT		 32
+#define RDATALIST_COUNT		 32
+
+/*
+ * internal state stuff.
+ */
+#define TO_FROM_UNKNOWN		0
+#define TO_FROM_FROMWIRE	1
+#define TO_FROM_TOWIRE		2
+
+/*
+ * "helper" type, which consists of a block of some type, and is linkable.
+ * For it to work, sizeof(dns_msgblock_t) must be a multiple of the pointer
+ * size, or the allocated elements will not be alligned correctly.
+ */
+struct dns_msgblock {
+	unsigned int			length;
+	unsigned int			remaining;
+	ISC_LINK(dns_msgblock_t)	link;
+}; /* dynamically sized */
 
 static inline void
-dns_msgblock_free(isc_mem_t *, dns_msgblock_t *);
-#define dns_msgblock_get(block, type) \
-	((type *)dns_msgblock__get(block, sizeof(type)))
+msgblock_free(isc_mem_t *, dns_msgblock_t *);
+#define msgblock_get(block, type) \
+	(((type) *)msgblock_internalget(block, sizeof(type)))
 
 static inline void *
-dns_msgblock__get(dns_msgblock_t *, unsigned int);
+msgblock_internalget(dns_msgblock_t *, unsigned int);
+
+static inline void
+msgblock_reset(dns_msgblock_t *, unsigned int);
 
 static inline dns_msgblock_t *
-dns_msgblock_allocate(isc_mem_t *, unsigned int, unsigned int);
+msgblock_allocate(isc_mem_t *, unsigned int, unsigned int);
 
 /*
  * Allocate a new dns_msgblock_t, and return a pointer to it.  If no memory
  * is free, return NULL.
  */
 static inline dns_msgblock_t *
-dns_msgblock_allocate(isc_mem_t *mctx, unsigned int sizeof_type,
-		      unsigned int count)
+msgblock_allocate(isc_mem_t *mctx, unsigned int sizeof_type,
+		  unsigned int count)
 {
 	dns_msgblock_t *block;
 	unsigned int length;
@@ -73,7 +115,7 @@ dns_msgblock_allocate(isc_mem_t *mctx, unsigned int sizeof_type,
  * NULL.
  */
 static inline void *
-dns_msgblock__get(dns_msgblock_t *block, unsigned int sizeof_type)
+msgblock_internalget(dns_msgblock_t *block, unsigned int sizeof_type)
 {
 	void *ptr;
 
@@ -89,11 +131,414 @@ dns_msgblock__get(dns_msgblock_t *block, unsigned int sizeof_type)
 	return (ptr);
 }
 
+static inline void
+msgblock_reset(dns_msgblock_t *block, unsigned int count)
+{
+	block->remaining = count;
+}
+
 /*
  * Release memory associated with a message block.
  */
 static inline void
-dns_msgblock_free(isc_mem_t *mctx, dns_msgblock_t *block)
+msgblock_free(isc_mem_t *mctx, dns_msgblock_t *block)
 {
 	isc_mem_put(mctx, block, block->length);
 }
+
+/*
+ * Init elements to default state.  Used both when allocating a new element
+ * and when resetting one.
+ */
+static inline void
+msginit(dns_message_t *m)
+{
+	m->id = 0;
+	m->flags = 0;
+	m->rcode = 0;
+	m->opcode = 0;
+	m->class = 0;
+	m->qcount = 0;
+	m->ancount = 0;
+	m->aucount = 0;
+	m->adcount = 0;
+	m->state = DNS_SECTION_ANY;  /* indicate nothing parsed or rendered */
+}
+
+/*
+ * Free all but one (or everything) for this message.  This is used by
+ * both dns_message_reset() and dns_message_parse().
+ */
+static void
+msgreset(dns_message_t *msg, isc_boolean_t everything)
+{
+	dns_msgblock_t *msgblock, *next_msgblock;
+	isc_dynbuffer_t *dynbuf, *next_dynbuf;
+	dns_rdataset_t *rds, *next_rds;
+	dns_name_t *name, *next_name;
+	unsigned int i;
+
+	/*
+	 * Clean up name lists by calling the rdataset disassociate function.
+	 */
+	for (i = 0 ; i < DNS_SECTION_MAX ; i++) {
+		name = ISC_LIST_HEAD(msg->sections[i]);
+		while (name != NULL) {
+			next_name = ISC_LIST_NEXT(name, link);
+			ISC_LIST_UNLINK(msg->sections[i], name, link);
+
+			rds = ISC_LIST_HEAD(name->list);
+			while (rds != NULL) {
+				next_rds = ISC_LIST_NEXT(rds, link);
+				ISC_LIST_UNLINK(name->list, rds, link);
+
+				dns_rdataset_disassociate(rds);
+				rds = next_rds;
+			}
+		}
+	}
+
+	/*
+	 * Clean up linked lists.
+	 */
+
+	dynbuf = ISC_LIST_HEAD(msg->scratchpad);
+	INSIST(dynbuf != NULL);
+	if (everything == ISC_FALSE) {
+		isc_dynbuffer_reset(dynbuf);
+		dynbuf = ISC_LIST_NEXT(dynbuf, link);
+	}
+	while (dynbuf != NULL) {
+		next_dynbuf = ISC_LIST_NEXT(dynbuf, link);
+		ISC_LIST_UNLINK(msg->scratchpad, dynbuf, link);
+		isc_dynbuffer_free(msg->mctx, &dynbuf);
+		dynbuf = next_dynbuf;
+	}
+
+	msgblock = ISC_LIST_HEAD(msg->names);
+	INSIST(msgblock != NULL);
+	if (everything == ISC_FALSE) {
+		msgblock_reset(msgblock, NAME_COUNT);
+		msgblock = ISC_LIST_NEXT(msgblock, link);
+	}
+	while (msgblock != NULL) {
+		next_msgblock = ISC_LIST_NEXT(msgblock, link);
+		ISC_LIST_UNLINK(msg->names, msgblock, link);
+		msgblock_free(msg->mctx, msgblock);
+		msgblock = next_msgblock;
+	}
+
+	msgblock = ISC_LIST_HEAD(msg->rdatas);
+	INSIST(msgblock != NULL);
+	if (everything == ISC_FALSE) {
+		msgblock_reset(msgblock, RDATA_COUNT);
+		msgblock = ISC_LIST_NEXT(msgblock, link);
+	}
+	while (msgblock != NULL) {
+		next_msgblock = ISC_LIST_NEXT(msgblock, link);
+		ISC_LIST_UNLINK(msg->rdatas, msgblock, link);
+		msgblock_free(msg->mctx, msgblock);
+		msgblock = next_msgblock;
+	}
+
+	if (msg->from_to_wire == DNS_MESSAGE_INTENT_PARSE) {
+		msgblock = ISC_LIST_HEAD(msg->rdatalists);
+		INSIST(msgblock != NULL);
+		if (everything == ISC_FALSE) {
+			msgblock_reset(msgblock, RDATALIST_COUNT);
+			msgblock = ISC_LIST_NEXT(msgblock, link);
+		}
+		while (msgblock != NULL) {
+			next_msgblock = ISC_LIST_NEXT(msgblock, link);
+			ISC_LIST_UNLINK(msg->rdatalists, msgblock, link);
+			msgblock_free(msg->mctx, msgblock);
+			msgblock = next_msgblock;
+		}
+	}
+
+	/*
+	 * Set other bits to normal default values.
+	 */
+	msginit(msg);
+}
+
+dns_result_t
+dns_message_create(isc_mem_t *mctx, dns_message_t **msg, unsigned int intent)
+{
+	dns_message_t *m;
+	isc_result_t iresult;
+	dns_msgblock_t *msgblock;
+	isc_dynbuffer_t *dynbuf;
+	unsigned int i;
+
+	REQUIRE(mctx != NULL);
+	REQUIRE(msg != NULL);
+	REQUIRE(*msg == NULL);
+	REQUIRE(intent == DNS_MESSAGE_INTENT_PARSE
+		|| intent == DNS_MESSAGE_INTENT_RENDER);
+
+	m = isc_mem_get(mctx, sizeof(dns_message_t));
+	if (m == NULL)
+		return(DNS_R_NOMEMORY);
+
+	m->magic = MESSAGE_MAGIC;
+	m->from_to_wire = intent;
+	msginit(m);
+	for (i = 0 ; i < DNS_SECTION_MAX ; i++)
+		ISC_LIST_INIT(m->sections[i]);
+	m->mctx = mctx;
+	ISC_LIST_INIT(m->scratchpad);
+	ISC_LIST_INIT(m->names);
+	ISC_LIST_INIT(m->rdatas);
+	ISC_LIST_INIT(m->rdatalists);
+
+	dynbuf = NULL;
+	iresult = isc_dynbuffer_allocate(mctx, &dynbuf, SCRATCHPAD_SIZE,
+					 ISC_BUFFERTYPE_BINARY);
+	if (iresult != ISC_R_SUCCESS)
+		goto cleanup1;
+	ISC_LIST_APPEND(m->scratchpad, dynbuf, link);
+
+	msgblock = msgblock_allocate(mctx, sizeof(dns_name_t),
+				     NAME_COUNT);
+	if (msgblock == NULL)
+		goto cleanup2;
+	ISC_LIST_APPEND(m->names, msgblock, link);
+
+	msgblock = msgblock_allocate(mctx, sizeof(dns_rdata_t),
+				     RDATA_COUNT);
+	if (msgblock == NULL)
+		goto cleanup3;
+	ISC_LIST_APPEND(m->rdatas, msgblock, link);
+
+	if (intent == DNS_MESSAGE_INTENT_PARSE) {
+		msgblock = msgblock_allocate(mctx, sizeof(dns_rdatalist_t),
+					     RDATALIST_COUNT);
+		if (msgblock == NULL)
+			goto cleanup4;
+		ISC_LIST_APPEND(m->rdatalists, msgblock, link);
+	}
+
+	return (DNS_R_SUCCESS);
+
+	/*
+	 * Cleanup for error returns.
+	 */
+ cleanup4:
+	msgblock = ISC_LIST_HEAD(m->rdatas);
+	msgblock_free(mctx, msgblock);
+ cleanup3:
+	msgblock = ISC_LIST_HEAD(m->names);
+	msgblock_free(mctx, msgblock);
+ cleanup2:
+	dynbuf = ISC_LIST_HEAD(m->scratchpad);
+	isc_dynbuffer_free(mctx, &dynbuf);
+ cleanup1:
+	m->magic = 0;
+	isc_mem_put(mctx, m, sizeof(dns_message_t));
+
+	return (DNS_R_NOMEMORY);
+}
+
+void
+dns_message_reset(dns_message_t *msg)
+{
+	msgreset(msg, ISC_FALSE);
+}
+
+void
+dns_message_destroy(dns_message_t **xmsg)
+{
+	dns_message_t *msg;
+
+	REQUIRE(xmsg != NULL);
+	REQUIRE(VALID_MESSAGE(*xmsg));
+
+	msg = *xmsg;
+	*xmsg = NULL;
+
+	msgreset(msg, ISC_TRUE);
+	msg->magic = 0;
+	isc_mem_put(msg->mctx, msg, sizeof(dns_message_t));
+}
+
+dns_result_t
+dns_message_parse(dns_message_t *msg, void *buffer, size_t buflen)
+{
+
+	REQUIRE(VALID_MESSAGE(msg));
+	REQUIRE(buffer != NULL);
+	REQUIRE(buflen > 0); /* XXXMLG Should be >= header length... */
+
+	/* XXX implement */
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+dns_result_t
+dns_message_renderbegin(dns_message_t *msg, isc_buffer_t *buffer)
+{
+	REQUIRE(VALID_MESSAGE(msg));
+	REQUIRE(buffer != NULL);
+
+	/* XXX implement */
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+dns_result_t
+dns_message_renderrelease(dns_message_t *msg, unsigned int space)
+{
+	REQUIRE(VALID_MESSAGE(msg));
+
+	if (msg->reserved < space)
+		return (DNS_R_NOSPACE);
+
+	msg->reserved -= space;
+
+	return (DNS_R_SUCCESS);
+}
+
+dns_result_t
+dns_message_renderreserve(dns_message_t *msg, isc_buffer_t *buffer,
+			  unsigned int space)
+{
+	isc_region_t r;
+
+	REQUIRE(VALID_MESSAGE(msg));
+	REQUIRE(buffer != NULL);
+
+	/*
+	 * "space" can be positive or negative.  If it is negative we are
+	 * removing our reservation of space.  If it is positive, we are
+	 * requesting more space to be reserved.
+	 */
+
+	isc_buffer_available(buffer, &r);
+	if (r.length < (space + msg->reserved))
+		return (DNS_R_NOSPACE);
+
+	msg->reserved += space;
+
+	return (DNS_R_SUCCESS);
+}
+
+dns_result_t
+dns_message_rendersection(dns_message_t *msg, isc_buffer_t *buffer,
+			  dns_section_t section, unsigned int priority,
+			  unsigned int flags)
+{
+	REQUIRE(VALID_MESSAGE(msg));
+	REQUIRE(buffer != NULL);
+	REQUIRE(VALID_NAMED_SECTION(section));
+
+	/* XXX implement */
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+dns_result_t
+dns_message_renderend(dns_message_t *msg, isc_buffer_t *buffer)
+{
+	REQUIRE(VALID_MESSAGE(msg));
+	REQUIRE(buffer != NULL);
+
+	/* XXX implement */
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+dns_result_t
+dns_message_firstname(dns_message_t *msg, dns_section_t section)
+{
+	REQUIRE(VALID_MESSAGE(msg));
+	REQUIRE(VALID_NAMED_SECTION(section));
+
+	msg->cursors[section] = ISC_LIST_HEAD(msg->sections[section]);
+
+	if (msg->cursors[section] == NULL)
+		return (DNS_R_NOMORE);
+
+	return (ISC_R_SUCCESS);
+}
+
+dns_result_t
+dns_message_nextname(dns_message_t *msg, dns_section_t section)
+{
+	
+	REQUIRE(VALID_MESSAGE(msg));
+	REQUIRE(VALID_NAMED_SECTION(section));
+	REQUIRE(msg->cursors[section] != NULL);
+	
+	msg->cursors[section] = ISC_LIST_NEXT(msg->cursors[section], link);
+
+	if (msg->cursors[section] == NULL)
+		return (DNS_R_NOMORE);
+
+	return (ISC_R_SUCCESS);
+}
+
+void
+dns_message_currentname(dns_message_t *msg, dns_section_t section,
+			dns_name_t **name)
+{