From 05dd8ff90a3eb38a5bb08638a4dc2a31c0344de3 Mon Sep 17 00:00:00 2001
From: Lubos Slovak <lubos.slovak@nic.cz>
Date: Thu, 23 Sep 2010 15:07:52 +0200
Subject: [PATCH] Rewrite of the answering algorithm (ns_answer()).
There are probably multiple bugs, needs a lot of testing and
revision of the algorithm.
However, it should mirror the current state of the flowchart
(230910-my).
---
samples/example.com.zone | 2 +
src/server/name-server.c | 238 +++++++++++++++++++--------------------
2 files changed, 119 insertions(+), 121 deletions(-)
diff --git a/samples/example.com.zone b/samples/example.com.zone
index 9eb06114e..bb4ccabc2 100644
--- a/samples/example.com.zone
+++ b/samples/example.com.zone
@@ -50,6 +50,8 @@ sub4 NS ns.example.com.
d.example.com. CNAME non-existing.example.com.
e.example.com. DNAME bogus25.com.
+f.example.com. CNAME e.example.com.
+g.example.com. CNAME www.bogus25.com.
f.g A 10.0.0.20
h.i.j.k A 10.0.0.21
diff --git a/src/server/name-server.c b/src/server/name-server.c
index b26303bad..d2f75ddb2 100644
--- a/src/server/name-server.c
+++ b/src/server/name-server.c
@@ -201,38 +201,11 @@ size_t ns_rrset_size( ldns_rr_list *rrset )
return size;
}
-/*----------------------------------------------------------------------------*/
-
-//const zn_node *ns_find_node_in_zone( const zdb_zone *zone, ldns_rdf **qname,
-// uint *labels )
-//{
-// const zn_node *node = NULL;
-// // search for the name and strip labels until nothing left
-// while ((*labels) > 0 &&
-// (node = zdb_find_name_in_zone(zone, *qname)) == NULL) {
-// debug_ns("Name %s not found, stripping leftmost label.\n",
-// ldns_rdf2str(*qname));
-// /* TODO: optimize!!!
-// * 1) do not copy the name!
-// * 2) implementation of ldns_dname_left_chop() is inefficient
-// */
-// ldns_rdf *new_qname = ldns_dname_left_chop(*qname);
-// ldns_rdf_deep_free(*qname);
-// *qname = new_qname;
-// --(*labels);
-// assert(*qname != NULL || (*labels) == 0);
-// }
-// assert((ldns_dname_label_count(*qname) == 0 && (*labels) == 0)
-// || (ldns_dname_label_count(*qname) > 0 && (*labels) > 0));
-
-// return node;
-//}
-
/*----------------------------------------------------------------------------*/
/*!
* @todo Check return values from push functions!
*/
-void ns_follow_cname( const zn_node **node, const ldns_rdf **qname,
+void ns_follow_cname( const zn_node **node, ldns_rdf **qname,
ldns_pkt *pkt, ldns_pkt_section section,
ldns_rr_list *copied_rrs )
{
@@ -268,7 +241,7 @@ void ns_follow_cname( const zn_node **node, const ldns_rdf **qname,
(*node) = zn_get_ref_cname(*node);
// save the new name which should be used for replacing wildcard
- *qname = ldns_rr_rdf(cname_rr, 0);
+ *qname = ldns_rdf_clone(ldns_rr_rdf(cname_rr, 0));
assert(ldns_rdf_get_type(*qname) == LDNS_RDF_TYPE_DNAME);
} while (*node != NULL && zn_has_cname(*node));
}
@@ -357,7 +330,7 @@ void ns_put_additional( const zn_node *node, ldns_pkt *response,
int count = ldns_pkt_ancount(response);
for (int i = 0; i < count; ++i) {
ldns_rr *rr = ldns_rr_list_rr(ldns_pkt_answer(response), i);
- const ldns_rdf *name;
+ ldns_rdf *name;
switch (ldns_rr_get_type(rr)) {
case LDNS_RR_TYPE_MX:
@@ -512,19 +485,6 @@ void ns_answer_from_node( const zn_node *node, const zdb_zone *zone,
ldns_pkt *response, ldns_rr_list *copied_rrs )
{
debug_ns("Putting answers from found node to the response...\n");
- if (zn_has_cname(node) > 0) {
- // resolve the cname chain and copy all CNAME records to the answer
- ns_follow_cname(&node, &qname, response, LDNS_SECTION_ANSWER,
- copied_rrs);
- // node is now set to the canonical name node (if found)
- if (node == NULL) {
- // TODO: add SOA
- //ns_put_authority_soa(zone, response);
- //ldns_pkt_set_rcode(response, LDNS_RCODE_NXDOMAIN);
- return;
- }
- }
- //assert(ldns_dname_compare(node->owner, qname) == 0);
ns_put_answer(node, qname, qtype, response, copied_rrs);
if (ldns_pkt_ancount(response) == 0) { // if NODATA response, put SOA
ns_put_authority_soa(zone, response);
@@ -620,12 +580,39 @@ void ns_process_dname( ldns_rr_list *dname_rrset, const ldns_rdf *qname,
copied_rrs);
ns_try_put_rrset(synth_cname, LDNS_SECTION_ANSWER, 1, response);
ldns_rr_list_free(synth_cname);
- ldns_pkt_set_rcode(response, LDNS_RCODE_NOERROR);
// do not search for the name in new zone (out-of-bailiwick)
}
/*----------------------------------------------------------------------------*/
+const zn_node *ns_strip_and_find( const zdb_zone *zone, ldns_rdf **qname,
+ uint *labels )
+{
+ const zn_node *node = NULL;
+ // search for the name and strip labels until nothing left
+ do {
+ debug_ns("Name %s not found, stripping leftmost label.\n",
+ ldns_rdf2str(*qname));
+ /* TODO: optimize!!!
+ * 1) do not copy the name!
+ * 2) implementation of ldns_dname_left_chop() is inefficient
+ */
+ ldns_rdf *new_qname = ldns_dname_left_chop(*qname);
+ ldns_rdf_deep_free(*qname);
+ *qname = new_qname;
+ --(*labels);
+ assert(*qname != NULL || (*labels) == 0);
+ node = zdb_find_name_in_zone(zone, *qname);
+ } while ((*labels) > 0 && node == NULL);
+
+ assert((ldns_dname_label_count(*qname) == 0 && (*labels) == 0)
+ || (ldns_dname_label_count(*qname) > 0 && (*labels) > 0));
+
+ return node;
+}
+
+/*----------------------------------------------------------------------------*/
+
void ns_answer( zdb_database *zdb, const ldns_rr *question, ldns_pkt *response,
ldns_rr_list *copied_rrs )
{
@@ -648,92 +635,101 @@ void ns_answer( zdb_database *zdb, const ldns_rr *question, ldns_pkt *response,
debug_ns("Found zone for QNAME %s\n", ldns_rdf2str(zone->zone_name));
debug_ns("Size of response packet: %u\n", ldns_pkt_size(response));
- // find proper zone node
- uint labels = ldns_dname_label_count(qname);
- uint labels_found = labels;
- const zn_node *node;
+ //const zn_node *node = ns_find_node_in_zone(zone, &qname, &labels_found);
+ const zn_node *node = zdb_find_name_in_zone(zone, qname);
+ int cname = 0;
- while (labels_found > 0 &&
- (node = zdb_find_name_in_zone(zone, qname)) == NULL) {
-search:
- debug_ns("Name %s not found, stripping leftmost label.\n",
- ldns_rdf2str(qname));
- /* TODO: optimize!!!
- * 1) do not copy the name!
- * 2) implementation of ldns_dname_left_chop() is inefficient
- */
- ldns_rdf *new_qname = ldns_dname_left_chop(qname);
- ldns_rdf_deep_free(qname);
- qname = new_qname;
- --labels_found;
- assert(qname != NULL || labels_found == 0);
- }
- assert((ldns_dname_label_count(qname) == 0 && labels_found == 0)
- || (ldns_dname_label_count(qname) > 0 && labels_found > 0));
-
- // if the name was not found in the zone something is wrong (SERVFAIL)
- if (labels_found == 0) {
- log_error("Name %s not found in zone %s! Returning SERVFAIL\n",
- ldns_rdf2str(ldns_rr_owner(question)),
- ldns_rdf2str(zone->zone_name));
- ldns_pkt_set_rcode(response, LDNS_RCODE_SERVFAIL);
- ldns_rdf_deep_free(qname);
- return;
- }
- assert(node != NULL);
+ while (1) {
+ uint labels = ldns_dname_label_count(qname);
+ uint labels_found = labels;
- // if the node is delegation point (no matter if whole QNAME was found)
- if (zn_is_delegation_point(node)) {
- ns_referral(node, response, copied_rrs);
- debug_ns("Size of response packet: %u\n", ldns_pkt_size(response));
- ldns_rdf_deep_free(qname);
- return;
- }
+ // whole QNAME not found
+ if (node == NULL) {
+ node = ns_strip_and_find(zone, &qname, &labels_found);
+
+ if (labels_found == 0) {
+ if (cname == 0) {
+ log_error("Name %s not found in zone %s! SERVFAIL.\n",
+ ldns_rdf2str(ldns_rr_owner(question)),
+ ldns_rdf2str(zone->zone_name));
+ ldns_pkt_set_rcode(response, LDNS_RCODE_SERVFAIL);
+ break;
+ } else {
+ ldns_pkt_set_rcode(response, LDNS_RCODE_NOERROR);
+ break;
+ }
+ }
+ assert(node != NULL);
+ }
- if (labels_found == labels) { // whole QNAME found
- debug_ns("All labels matched.\n");
- // if an empty non-terminal, continue the search
- if (zn_is_empty(node) == 0) {
- goto search;
+ // if the node is delegation point (no matter if whole QNAME was found)
+ if (zn_is_delegation_point(node)) {
+ ns_referral(node, response, copied_rrs);
+ debug_ns("Size of response packet: %u\n", ldns_pkt_size(response));
+ break;
}
- ns_answer_from_node(node, zone, qname, ldns_rr_get_type(question),
- response, copied_rrs);
- } else { // only part of QNAME found
- debug_ns("Found node with name: %s (rest of QNAME: %s).\n",
- ldns_rdf2str(node->owner), ldns_rdf2str(qname));
-
- // check if DNAME is present
- ldns_rr_list *dname_rrset = NULL;
- if ((dname_rrset = zn_find_rrset(node, LDNS_RR_TYPE_DNAME)) != NULL) {
- ns_process_dname(dname_rrset, ldns_rr_owner(question), response,
- copied_rrs);
- } else {
- // try to find a wildcard child
- ldns_rdf *wildcard = ldns_dname_new_frm_str("*");
- if (ldns_dname_cat(wildcard, qname) != LDNS_STATUS_OK) {
- log_error("Unknown error occured.\n");
- ldns_pkt_set_rcode(response, LDNS_RCODE_SERVFAIL);
- ldns_rdf_deep_free(wildcard);
- ldns_rdf_deep_free(qname);
- return; // need some return value??
- }
- const zn_node *wildcard_node =
- zdb_find_name_in_zone(zone, wildcard);
- if (wildcard_node != NULL) {
- debug_ns("Found wildcard node %s, answering.\n", ldns_rdf2str(
- wildcard_node->owner));
- ns_answer_from_node(
- wildcard_node, zone, ldns_rr_owner(question),
- ldns_rr_get_type(question), response, copied_rrs);
+ if (labels_found < labels) {
+ // check if DNAME is present
+ ldns_rr_list *dname_rrset = NULL;
+ if ((dname_rrset = zn_find_rrset(node, LDNS_RR_TYPE_DNAME))
+ != NULL) {
+ ns_process_dname(dname_rrset, ldns_rr_owner(question), response,
+ copied_rrs);
} else {
- // return NXDOMAIN
- ldns_pkt_set_rcode(response, LDNS_RCODE_NXDOMAIN);
+ debug_ns("Trying to find wildcard child of node %s.\n",
+ ldns_rdf2str(qname));
+ // try to find a wildcard child
+ ldns_rdf *wildcard = ldns_dname_new_frm_str("*");
+ if (ldns_dname_cat(wildcard, qname) != LDNS_STATUS_OK) {
+ log_error("Unknown error occured.\n");
+ ldns_pkt_set_rcode(response, LDNS_RCODE_SERVFAIL);
+ ldns_rdf_deep_free(wildcard);
+ break; // need some return value??
+ }
+
+ const zn_node *wildcard_node =
+ zdb_find_name_in_zone(zone, wildcard);
ldns_rdf_deep_free(wildcard);
+
+ debug_ns("Found node: %p\n", wildcard_node);
+
+ if (wildcard_node == NULL) {
+ if (cname == 0) {
+ // return NXDOMAIN
+ ldns_pkt_set_rcode(response, LDNS_RCODE_NXDOMAIN);
+ } else {
+ ldns_pkt_set_rcode(response, LDNS_RCODE_NOERROR);
+ }
+ break;
+ } else {
+ node = wildcard_node;
+ debug_ns("Node's owner: %s\n", ldns_rdf2str(node->owner));
+ }
+ }
+ }
+
+ if (zn_has_cname(node)) {
+ ldns_rdf *act_name = qname;
+ ns_follow_cname(&node, &act_name, response, LDNS_SECTION_ANSWER,
+ copied_rrs);
+ if (act_name != qname) {
ldns_rdf_deep_free(qname);
- return;
+ qname = act_name;
+ }
+ cname = 1;
+ if (node == NULL) {
+ continue; // hm, infinite loop better than goto? :)
+ }
+ } else {
+ if (ldns_dname_is_wildcard(node->owner)) {
+ ldns_rdf_deep_free(qname);
+ qname = ldns_rdf_clone(ldns_rr_owner(question));
}
- ldns_rdf_deep_free(wildcard);
+ ns_answer_from_node(node, zone, qname,
+ ldns_rr_get_type(question), response, copied_rrs);
+ ldns_pkt_set_rcode(response, LDNS_RCODE_NOERROR);
+ break;
}
}
--
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