RRSets: allow TTL updates over DDNS

src/knot/updates/apply.c

@@ -20,6 +20,7 @@
 #include "knot/updates/changesets.h"
 #include "knot/zone/zone.h"
 #include "knot/zone/zonefile.h"
+#include "knot/common/log.h"
 #include "libknot/libknot.h"
 #include "libknot/internal/lists.h"
 #include "libknot/internal/macros.h"
@@ -303,11 +304,8 @@ static int add_rr(const zone_contents_t *zone, zone_node_t *node,
 
 		if (ret == KNOT_ETTL) {
 			// Handle possible TTL errors.
-			log_ttl_error(zone, node, rr);
-			if (!master) {
-				// TTL errors fatal only for master.
-				return KNOT_EOK;
-			}
+			log_zone_notice(zone->apex->owner, "TTL mismatch, value updated");
+			return KNOT_EOK;
 		}
 	}
 

src/knot/zone/node.c

@@ -76,10 +76,8 @@ static bool ttl_error(struct rr_data *node_data, const knot_rrset_t *rrset)
 		return false;
 	}
 
-	const uint32_t inserted_ttl = knot_rdata_ttl(knot_rdataset_at(&rrset->rrs, 0));
-	// Get first RR from node.
-	const knot_rdata_t *node_rdata = knot_rdataset_at(&node_data->rrs, 0);
-	const uint32_t node_ttl = knot_rdata_ttl(node_rdata);
+	const uint32_t inserted_ttl = knot_rdataset_ttl(&rrset->rrs);
+	const uint32_t node_ttl = knot_rdataset_ttl(&node_data->rrs);
 	// Return error if TTLs don't match.
 	return inserted_ttl != node_ttl;
 }
@@ -179,6 +177,11 @@ int node_add_rrset(zone_node_t *node, const knot_rrset_t *rrset, mm_ctx_t *mm)
 		if (node->rrs[i].type == rrset->type) {
 			struct rr_data *node_data = &node->rrs[i];
 			const bool ttl_err = ttl_error(node_data, rrset);
+			if (ttl_err) {
+				knot_rdataset_set_ttl(&node_data->rrs,
+				                      knot_rdataset_ttl(&rrset->rrs));
+			}
+
 			int ret = knot_rdataset_merge(&node_data->rrs,
 			                              &rrset->rrs, mm);
 			if (ret != KNOT_EOK) {

src/libknot/rdataset.c

@@ -201,6 +201,21 @@ size_t knot_rdataset_size(const knot_rdataset_t *rrs)
 	return total_size;
 }
 
+_public_
+uint32_t knot_rdataset_ttl(const knot_rdataset_t *rrs)
+{
+	return knot_rdata_ttl(knot_rdataset_at(rrs, 0));
+}
+
+_public_
+void knot_rdataset_set_ttl(knot_rdataset_t *rrs, uint32_t ttl)
+{
+	for (uint16_t i = 0; i < rrs->rr_count; ++i) {
+		knot_rdata_t *rrset_rr = knot_rdataset_at(rrs, i);
+		knot_rdata_set_ttl(rrset_rr, ttl);
+	}
+}
+
 _public_
 int knot_rdataset_add(knot_rdataset_t *rrs, const knot_rdata_t *rr, mm_ctx_t *mm)
 {

src/libknot/rdataset.h

@@ -80,6 +80,21 @@ knot_rdata_t *knot_rdataset_at(const knot_rdataset_t *rrs, size_t pos);
  */
 size_t knot_rdataset_size(const knot_rdataset_t *rrs);
 
+/*!
+ * \brief Returns the common TTL of the RR set.
+ * \note Actually returns the TTL of the first RR.
+ * \param rrs  RR array.
+ * \return TTL.
+ */
+uint32_t knot_rdataset_ttl(const knot_rdataset_t *rrs);
+
+/*!
+ * \brief Sets TTL of all the RRs in the RR set.
+ * \param rrs  RR array.
+ * \param ttl  TTL to set.
+ */
+void knot_rdataset_set_ttl(knot_rdataset_t *rrs, uint32_t ttl);
+
 /* ----------------------- RRs RR manipulation ------------------------------ */
 
 /*!

tests-extra/tests/ddns/ttl/test.py

@@ -15,15 +15,15 @@ t.link(zone, master, ddns=True)
 t.start()
 
 # Add new RR with different TTL to a RRSet that is already in the zone
-# The UPDATE should be REFUSED
+# The UPDATE should be accepted and all previous TTLs should change to be the same value
 
 check_log("Add RR with different TTL")
 up = master.update(zone)
 up.add("mail.example.com.", 1000, "A", "1.2.3.4")
-up.send("REFUSED")
+up.send("NOERROR")
 resp = master.dig("mail.example.com.", "A")
-resp.check_record(section="answer", rtype="A", ttl="3600", rdata="192.0.2.3")
-resp.check_record(section="answer", rtype="A", nordata="1.2.3.4")
+resp.check_record(section="answer", rtype="A", ttl="1000", rdata="192.0.2.3")
+resp.check_record(section="answer", rtype="A", ttl="1000", rdata="1.2.3.4")
 
 # Try to add two RRs belonging to one RRSet, but with different TTLs
 # The UPDATE should be REFUSED
@@ -35,7 +35,6 @@ up.add("test.example.com.", 1000, "A", "1.2.3.4")
 up.add("test.example.com.", 2000, "A", "2.3.4.5")
 up.send("REFUSED")
 resp = master.dig("test.example.com.", "A")
-resp.check(rcode="NXDOMAIN")
 
 # First, delete RRSet already in zone, then add new RR with different TTL
 # The UPDATE should be accepted and the new RR should be present in the zone
@@ -57,19 +56,18 @@ up.add("test2.example.com.", 3600, "A", "2.3.4.5")
 up.send("NOERROR")
 
 # Delete one of RRs in a zone RRSet, then add new RR with different TTL
-# The UPDATE should be REFUSED
-# This also tests rollback in case of deletion
+# The UPDATE should be accepted, old TTLs shall change to the new value
 
 check_log("Delete one RR from a RRSet + try to add RR with different TTL instead")
 up = master.update(zone)
 up.delete("test2.example.com.", "A", "1.2.3.4")
 up.add("test2.example.com.", 1000, "A", "3.4.5.6")
-up.send("REFUSED")
+up.send("NOERROR")
 resp = master.dig("test2.example.com.", "A")
-resp.check_record(section="answer", rtype="A", ttl="3600", rdata="1.2.3.4")
-resp.check_record(section="answer", rtype="A", nordata="3.4.5.6")
+resp.check_record(section="answer", rtype="A", nordata="1.2.3.4")
+resp.check_record(section="answer", rtype="A", ttl="1000", rdata="3.4.5.6")
 
-# Test for rollback - a lot of changes and a invalid RR
+# Test for rollback - a lot of changes and an invalid RR
 
 check_log("Rollback test: a lot of changes")
 up = master.update(zone)
@@ -87,12 +85,14 @@ up.delete("mail.example.com.", "A")
 # Remove whole node
 up.delete("dns1.example.com.", "ANY")
 # Add invalid RR so that the UPDATE is refused
-up.add("test2.example.com.", 1000, "A", "7.8.9.0")
-up.send("REFUSED")
+up.prereq_yx("notexisting.com.")
+up.delete("test2.notexisting.com.", "A", "7.8.9.0")
+up.send("NOTZONE")
 
 resp = master.dig("test2.example.com.", "ANY")
-resp.check_record(section="answer", rtype="A", ttl="3600", rdata="1.2.3.4")
-resp.check_record(section="answer", rtype="A", ttl="3600", rdata="2.3.4.5")
+resp.check_record(section="answer", rtype="A", nordata="1.2.3.4")
+resp.check_record(section="answer", rtype="A", ttl="1000", rdata="2.3.4.5")
+resp.check_record(section="answer", rtype="A", ttl="1000", rdata="3.4.5.6")
 resp.check_record(section="answer", rtype="MX", nordata="10 somewhere.com.")
 resp.check_record(section="answer", rtype="A", nordata="7.8.9.0")