Implementation of draft-ubbink-dnsop-backend-serial-zoneversion

dname.c

@@ -717,3 +717,41 @@ dname_make_from_packet_buffered(struct dname_buffer* dname,
 	assert(wirelen == dname->dname.name_size);
 	return wirelen;
 }
+
+dname_type*
+label_plus_dname(const char* label, const dname_type* dname)
+{
+	static struct {
+		dname_type dname;
+		uint8_t bytes[MAXDOMAINLEN + 128 /* max number of labels */];
+	} ATTR_PACKED name;
+	size_t i, ll;
+
+	if (!label || !dname || dname->label_count > 127)
+		return NULL;
+	ll = strlen(label);
+	if ((int)dname->name_size + ll + 1 > MAXDOMAINLEN)
+		return NULL;
+
+	/* In reversed order and first copy with memmove, so we can nest.
+	 * i.e. label_plus_dname(label1, label_plus_dname(label2, dname))
+	 */
+	memmove(name.bytes + dname->label_count
+			+ 1 /* label_count increases by one */
+			+ 1 /* label type/length byte for label */ + ll,
+		((char*)dname) + sizeof(dname_type) + dname->label_count,
+		dname->name_size);
+	memcpy(name.bytes + dname->label_count
+			+ 1 /* label_count increases by one */
+			+ 1 /* label type/length byte for label */, label, ll);
+	name.bytes[dname->label_count + 1] = ll; /* label type/length byte */
+	name.bytes[dname->label_count] = 0; /* first label follows last
+	                                     * label_offsets element */
+	for (i = 0; i < dname->label_count; i++)
+		name.bytes[i] = ((uint8_t*)(void*)dname)[sizeof(dname_type)+i]
+			+ 1 /* label type/length byte for label */ + ll;
+	name.dname.label_count = dname->label_count + 1 /* label_count incr. */;
+	name.dname.name_size   = dname->name_size   + ll
+	                                            + 1 /* label length */;
+	return &name.dname;
+}

dname.h

@@ -448,4 +448,7 @@ int dname_make_buffered(struct dname_buffer* dname, uint8_t *name,
 int dname_make_from_packet_buffered(struct dname_buffer* dname,
 	buffer_type *packet, int allow_pointers, int normalize);
 
+/** return (static) dname with label prepended to dname */
+dname_type* label_plus_dname(const char* label,const dname_type* dname);
+
 #endif /* DNAME_H */

edns.c

@@ -71,6 +71,8 @@ edns_init_record(edns_record_type *edns)
 	edns->dnssec_ok = 0;
 	edns->nsid = 0;
 	edns->zoneversion = 0;
+	edns->backend_version_rr = NULL;
+	edns->backend_version_len = 0;
 	edns->padding = 0;
 	edns->cookie_status = COOKIE_NOT_PRESENT;
 	edns->cookie_len = 0;

edns.h

@@ -13,6 +13,7 @@
 #include "buffer.h"
 struct nsd;
 struct query;
+struct rr;
 
 #define OPT_LEN 9U                      /* Length of the NSD EDNS response record minus 2 */
 #define OPT_RDATA 2                     /* holds the rdata length comes after OPT_LEN */
@@ -25,7 +26,8 @@ struct query;
 #define DNSSEC_OK_MASK  0x8000U         /* do bit mask */
 
 /* https://iana.org/assignments/dns-parameters/#zoneversion-type-values */
-#define ZONEVERSION_SOA_SERIAL 0
+#define ZONEVERSION_SOA_SERIAL     0
+#define ZONEVERSION_BACKEND_SERIAL 247 /* BACKEND-SERIAL ZONEVERSION type */
 
 /* See RFC 8467 */
 #define PADDING_BLOCK_SZ 468
@@ -68,6 +70,8 @@ struct edns_record
 	int                dnssec_ok;
 	int                nsid;
 	int                zoneversion;
+	struct rr*         backend_version_rr;
+	size_t             backend_version_len;
 	int                padding;
 	cookie_status_type cookie_status;
 	size_t             cookie_len;

query.c

@@ -1813,6 +1813,8 @@ void
 query_add_optional(query_type *q, nsd_type *nsd, uint32_t *now_p)
 {
 	struct edns_data *edns = &nsd->edns_ipv4;
+	domain_type *match, *closest_encloser;
+	rrset_type *rrset;
 #if defined(INET6)
 	if (q->client_addr.ss_family == AF_INET6) {
 		edns = &nsd->edns_ipv6;
@@ -1836,11 +1838,42 @@ query_add_optional(query_type *q, nsd_type *nsd, uint32_t *now_p)
 				6 + ( q->edns.ede_text_len
 			            ? q->edns.ede_text_len : 0);
 
-		if(q->edns.zoneversion
-		&& q->zone
-		&& q->zone->soa_rrset
-		&& q->zone->soa_rrset->rr_count >= 1
-		&& q->zone->soa_rrset->rrs[0]->rdlength >= 20 /* 5x 32bit numbers */ +2*sizeof(void*) /* two pointers to domain names */)
+		if(!q->edns.zoneversion || !q->zone)
+			; /* pass */
+		else if(namedb_lookup( nsd->db
+		                     , label_plus_dname("_backend-version"
+		                                       , domain_dname_const(q->zone->apex))
+				     , &match, &closest_encloser)
+		     && (rrset = domain_find_rrset(match, q->zone, TYPE_TXT))
+		     && rrset->rr_count == 1) {
+			uint8_t *rdp = rrset->rrs[0]->rdata;
+			uint8_t *eo_rd = rrset->rrs[0]->rdata
+			               + rrset->rrs[0]->rdlength;
+			while (rdp < eo_rd) {
+				q->edns.backend_version_len += *rdp;
+				rdp += *rdp + 1;
+			}
+			if(rdp == eo_rd) {
+				q->edns.backend_version_rr = rrset->rrs[0];
+				q->edns.opt_reserved_space += sizeof(uint16_t)
+							   +  sizeof(uint16_t)
+							   +  sizeof(uint8_t)
+							   +  sizeof(uint8_t)
+							   +  q->edns.backend_version_len;
+
+			} else if(q->zone->soa_rrset
+			       && q->zone->soa_rrset->rr_count >= 1
+			       && q->zone->soa_rrset->rrs[0]->rdlength >= 20+2*sizeof(void*)) {
+				q->edns.opt_reserved_space += sizeof(uint16_t)
+							   +  sizeof(uint16_t)
+							   +  sizeof(uint8_t)
+							   +  sizeof(uint8_t)
+							   +  sizeof(uint32_t);
+			}
+		}
+		else if(q->zone->soa_rrset
+		     && q->zone->soa_rrset->rr_count >= 1
+		     && q->zone->soa_rrset->rrs[0]->rdlength >= 20 /* 5x 32bit numbers */ +2*sizeof(void*) /* two pointers to domain names */)
 			q->edns.opt_reserved_space += sizeof(uint16_t)
 			                           +  sizeof(uint16_t)
 			                           +  sizeof(uint8_t)
@@ -1875,11 +1908,32 @@ query_add_optional(query_type *q, nsd_type *nsd, uint32_t *now_p)
 				/* nsid payload */
 				buffer_write(q->packet, nsd->nsid, nsd->nsid_len);
 			}
-			if(q->edns.zoneversion
-			&& q->zone
-			&& q->zone->soa_rrset
-			&& q->zone->soa_rrset->rr_count >= 1
-			&& q->zone->soa_rrset->rrs[0]->rdlength >= 20+2*sizeof(void*) /* 5x4 bytes and 2 pointers to domains */ ) {
+			if(!q->edns.zoneversion || !q->zone)
+				; /* pass */
+			else if(q->edns.backend_version_rr) {
+				uint8_t *rdp = q->edns.backend_version_rr->rdata;
+				uint8_t *eo_rd = q->edns.backend_version_rr->rdata
+					       + q->edns.backend_version_rr->rdlength;
+
+				buffer_write_u16(q->packet, ZONEVERSION_CODE);
+				buffer_write_u16( q->packet
+				                , sizeof(uint8_t)
+						+ sizeof(uint8_t)
+						+ q->edns.backend_version_len);
+				buffer_write_u8(q->packet,
+				    domain_dname(q->zone->apex)->label_count - 1);
+				buffer_write_u8( q->packet
+				               , ZONEVERSION_BACKEND_SERIAL);
+				while (rdp < eo_rd) {
+					buffer_write(q->packet, rdp+1, *rdp);
+					q->edns.backend_version_len += *rdp;
+					rdp += *rdp + 1;
+				}
+				assert(rdp == eo_rd);
+
+			} else if(q->zone->soa_rrset
+			       && q->zone->soa_rrset->rr_count >= 1
+			       && q->zone->soa_rrset->rrs[0]->rdlength >= 20+2*sizeof(void*) /* 5x4 bytes and 2 pointers to domains */ ) {
 				uint32_t serial = 0;
 				buffer_write_u16(q->packet, ZONEVERSION_CODE);
 				buffer_write_u16( q->packet

xfrd-catalog-zones.c

@@ -27,9 +27,6 @@ static void vmake_catalog_consumer_invalid(
 	struct xfrd_catalog_consumer_zone *consumer_zone,
 	const char *format, va_list args);
 
-/** return (static) dname with label prepended to dname */
-static dname_type* label_plus_dname(const char* label,const dname_type* dname);
-
 /** delete the catalog member zone */
 static void catalog_del_consumer_member_zone(
 		struct xfrd_catalog_consumer_zone* consumer_zone,
@@ -304,44 +301,6 @@ make_catalog_consumer_valid(struct xfrd_catalog_consumer_zone *consumer_zone)
 	}
 }
 
-static dname_type*
-label_plus_dname(const char* label, const dname_type* dname)
-{
-	static struct {
-		dname_type dname;
-		uint8_t bytes[MAXDOMAINLEN + 128 /* max number of labels */];
-	} ATTR_PACKED name;
-	size_t i, ll;
-
-	if (!label || !dname || dname->label_count > 127)
-		return NULL;
-	ll = strlen(label);
-	if ((int)dname->name_size + ll + 1 > MAXDOMAINLEN)
-		return NULL;
-
-	/* In reversed order and first copy with memmove, so we can nest.
-	 * i.e. label_plus_dname(label1, label_plus_dname(label2, dname))
-	 */
-	memmove(name.bytes + dname->label_count
-			+ 1 /* label_count increases by one */
-			+ 1 /* label type/length byte for label */ + ll,
-		((char*)dname) + sizeof(dname_type) + dname->label_count,
-		dname->name_size);
-	memcpy(name.bytes + dname->label_count
-			+ 1 /* label_count increases by one */
-			+ 1 /* label type/length byte for label */, label, ll);
-	name.bytes[dname->label_count + 1] = ll; /* label type/length byte */
-	name.bytes[dname->label_count] = 0; /* first label follows last
-	                                     * label_offsets element */
-	for (i = 0; i < dname->label_count; i++)
-		name.bytes[i] = ((uint8_t*)(void*)dname)[sizeof(dname_type)+i]
-			+ 1 /* label type/length byte for label */ + ll;
-	name.dname.label_count = dname->label_count + 1 /* label_count incr. */;
-	name.dname.name_size   = dname->name_size   + ll
-	                                            + 1 /* label length */;
-	return &name.dname;
-}
-
 static void
 catalog_del_consumer_member_zone(
 		struct xfrd_catalog_consumer_zone* consumer_zone,