From e3ac047b23c34609cb247d9c4becb416ae5e2b73 Mon Sep 17 00:00:00 2001
From: alessio <alessio@isc.org>
Date: Tue, 5 Nov 2024 09:36:24 +0100
Subject: [PATCH] Pack structures more tightly

---
 lib/dns/include/dns/name.h      | 10 +++++++---
 lib/dns/include/dns/rdata.h     |  9 +++++----
 lib/dns/include/dns/rdataslab.h | 29 ++++++++++++-----------------
 lib/dns/name.c                  |  5 ++---
 lib/dns/nsec3.c                 |  2 +-
 lib/dns/zone.c                  |  4 ++--
 6 files changed, 29 insertions(+), 30 deletions(-)

diff --git a/lib/dns/include/dns/name.h b/lib/dns/include/dns/name.h
index 740fb9c3f9..76a0e0eaaa 100644
--- a/lib/dns/include/dns/name.h
+++ b/lib/dns/include/dns/name.h
@@ -97,9 +97,11 @@ ISC_LANG_BEGINDECLS
  */
 struct dns_name {
 	unsigned int   magic;
-	unsigned char *ndata;
-	unsigned int   length;
-	unsigned int   labels;
+#pragma pack(push, 1)
+	uint8_t   length;
+	uint8_t   labels;
+#pragma pack(pop)
+#pragma pack(push, 2)
 	struct dns_name_attrs {
 		bool absolute	  : 1; /*%< Used by name.c */
 		bool readonly	  : 1; /*%< Used by name.c */
@@ -116,6 +118,8 @@ struct dns_name {
 		bool update	  : 1; /*%< Used by client. */
 		bool hasupdaterec : 1; /*%< Used by client. */
 	} attributes;
+#pragma pack(pop)
+	unsigned char *ndata;
 	unsigned char *offsets;
 	isc_buffer_t  *buffer;
 	ISC_LINK(dns_name_t) link;
diff --git a/lib/dns/include/dns/rdata.h b/lib/dns/include/dns/rdata.h
index 36f79c8edd..2d2200655b 100644
--- a/lib/dns/include/dns/rdata.h
+++ b/lib/dns/include/dns/rdata.h
@@ -109,17 +109,18 @@ ISC_LANG_BEGINDECLS
  * purpose the client desires.
  */
 struct dns_rdata {
-	unsigned char	*data;
-	unsigned int	 length;
 	dns_rdataclass_t rdclass;
 	dns_rdatatype_t	 type;
-	unsigned int	 flags;
+	uint16_t	 length;
+	uint16_t	 flags;
+	unsigned char	*data;
 	ISC_LINK(dns_rdata_t) link;
 };
 
+// *data, len , rdclass, type, flags, link
 #define DNS_RDATA_INIT                                           \
 	{                                                        \
-		NULL, 0, 0, 0, 0, { (void *)(-1), (void *)(-1) } \
+		0, 0, 0, 0, NULL, { (void *)(-1), (void *)(-1) } \
 	}
 
 #define DNS_RDATA_CHECKINITIALIZED
diff --git a/lib/dns/include/dns/rdataslab.h b/lib/dns/include/dns/rdataslab.h
index 4a0d58a542..7eb70e7c58 100644
--- a/lib/dns/include/dns/rdataslab.h
+++ b/lib/dns/include/dns/rdataslab.h
@@ -68,31 +68,27 @@ struct dns_slabheader_proof {
 };
 
 struct dns_slabheader {
-	/*%
-	 * Locked by the owning node's lock.
-	 */
-	uint32_t	      serial;
-	dns_ttl_t	      ttl;
-	dns_typepair_t	      type;
-	atomic_uint_least16_t attributes;
-	dns_trust_t	      trust;
+	// 2
+	_Atomic(uint16_t) attributes;		// Locked by the owning node's lock.
+	dns_trust_t	      trust;		// Locked by the owning node's lock.
+	// 4
+	uint32_t	      serial;		// Locked by the owning node's lock.
+	dns_ttl_t	      ttl;		// Locked by the owning node's lock.
+	dns_typepair_t	      type;		// Locked by the owning node's lock.
 
-	unsigned int heap_index;
-	/*%<
-	 * Used for TTL-based cache cleaning.
-	 */
-
-	isc_stdtime_t resign;
+	_Atomic(uint16_t) count;
 	unsigned int  resign_lsb : 1;
 
-	atomic_uint_fast16_t count;
+	isc_stdtime_t resign;
+	unsigned int heap_index;
 	/*%<
 	 * Monotonically increased every time this rdataset is bound so that
 	 * it is used as the base of the starting point in DNS responses
 	 * when the "cyclic" rrset-order is required.
 	 */
 
-	atomic_uint_fast32_t last_refresh_fail_ts;
+	isc_stdtime_t last_used;
+	_Atomic(uint32_t) last_refresh_fail_ts;
 
 	dns_slabheader_proof_t *noqname;
 	dns_slabheader_proof_t *closest;
@@ -122,7 +118,6 @@ struct dns_slabheader {
 	 * this rdataset, if any.
 	 */
 
-	isc_stdtime_t last_used;
 	ISC_LINK(struct dns_slabheader) link;
 
 	/*%
diff --git a/lib/dns/name.c b/lib/dns/name.c
index 32770402ba..3ee12464a7 100644
--- a/lib/dns/name.c
+++ b/lib/dns/name.c
@@ -107,8 +107,7 @@ dns_name_isvalid(const dns_name_t *name) {
 		return (false);
 	}
 
-	if (name->length > DNS_NAME_MAXWIRE ||
-	    name->labels > DNS_NAME_MAXLABELS)
+	if (name->labels > DNS_NAME_MAXLABELS)
 	{
 		return (false);
 	}
@@ -616,7 +615,7 @@ dns_name_getlabel(const dns_name_t *name, unsigned int n, dns_label_t *label) {
 	SETUP_OFFSETS(name, offsets, odata);
 
 	label->base = &name->ndata[offsets[n]];
-	if (n == name->labels - 1) {
+	if (n == (unsigned int) name->labels - 1) {
 		label->length = name->length - offsets[n];
 	} else {
 		label->length = offsets[n + 1] - offsets[n];
diff --git a/lib/dns/nsec3.c b/lib/dns/nsec3.c
index e92557e002..ae283e5825 100644
--- a/lib/dns/nsec3.c
+++ b/lib/dns/nsec3.c
@@ -995,7 +995,7 @@ void
 dns_nsec3param_toprivate(dns_rdata_t *src, dns_rdata_t *target,
 			 dns_rdatatype_t privatetype, unsigned char *buf,
 			 size_t buflen) {
-	REQUIRE(buflen >= src->length + 1);
+	REQUIRE(buflen >= (unsigned int) src->length + 1);
 
 	REQUIRE(DNS_RDATA_INITIALIZED(target));
 
diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 828f61161c..5b35a85a30 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -17192,7 +17192,7 @@ getprivate:
 			{
 				next = ISC_LIST_NEXT(nsec3p, link);
 
-				if (nsec3p->length == rdata.length + 1 &&
+				if (nsec3p->length == (unsigned int) rdata.length + 1 &&
 				    memcmp(rdata.data, nsec3p->data + 1,
 					   nsec3p->length - 1) == 0)
 				{
@@ -23773,7 +23773,7 @@ rss_post(void *arg) {
 			dns_rdata_init(&rdata);
 			dns_rdataset_current(&nrdataset, &rdata);
 
-			if (np->length == (rdata.length + 1) &&
+			if (np->length == ((unsigned int) rdata.length + 1) &&
 			    memcmp(rdata.data, np->data + 1, np->length - 1) ==
 				    0)
 			{