1 files changed, 90 insertions, 4 deletions

diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c
index f7cb84e2a6..c1cd650651 100644
--- a/src/resolve/resolved-dns-query.c
+++ b/src/resolve/resolved-dns-query.c
@@ -30,6 +30,7 @@
 
 #define CNAME_MAX 8
 #define QUERIES_MAX 2048
+#define AUXILIARY_QUERIES_MAX 64
 
 static void dns_query_stop(DnsQuery *q) {
         DnsTransaction *t;
@@ -48,6 +49,15 @@ DnsQuery *dns_query_free(DnsQuery *q) {
         if (!q)
                 return NULL;
 
+        while (q->auxiliary_queries)
+                dns_query_free(q->auxiliary_queries);
+
+        if (q->auxiliary_for) {
+                assert(q->auxiliary_for->n_auxiliary_queries > 0);
+                q->auxiliary_for->n_auxiliary_queries--;
+                LIST_REMOVE(auxiliary_queries, q->auxiliary_for->auxiliary_queries, q);
+        }
+
         dns_query_stop(q);
         set_free(q->transactions);
 
@@ -111,6 +121,29 @@ int dns_query_new(Manager *m, DnsQuery **ret, DnsQuestion *question, int ifindex
         return 0;
 }
 
+int dns_query_make_auxiliary(DnsQuery *q, DnsQuery *auxiliary_for) {
+        assert(q);
+        assert(auxiliary_for);
+
+        /* Ensure that that the query is not auxiliary yet, and
+         * nothing else is auxiliary to it either */
+        assert(!q->auxiliary_for);
+        assert(!q->auxiliary_queries);
+
+        /* Ensure that the unit we shall be made auxiliary for isn't
+         * auxiliary itself */
+        assert(!auxiliary_for->auxiliary_for);
+
+        if (auxiliary_for->n_auxiliary_queries >= AUXILIARY_QUERIES_MAX)
+                return -EAGAIN;
+
+        LIST_PREPEND(auxiliary_queries, auxiliary_for->auxiliary_queries, q);
+        q->auxiliary_for = auxiliary_for;
+
+        auxiliary_for->n_auxiliary_queries++;
+        return 0;
+}
+
 static void dns_query_complete(DnsQuery *q, DnsTransactionState state) {
         assert(q);
         assert(!IN_SET(state, DNS_TRANSACTION_NULL, DNS_TRANSACTION_PENDING));
@@ -622,7 +655,7 @@ int dns_query_go(DnsQuery *q) {
         assert(q->question);
         assert(q->question->n_keys > 0);
 
-        name = DNS_RESOURCE_KEY_NAME(q->question->keys[0]);
+        name = dns_question_name(q->question);
 
         LIST_FOREACH(scopes, s, q->manager->dns_scopes) {
                 DnsScopeMatch match;
@@ -831,12 +864,13 @@ void dns_query_ready(DnsQuery *q) {
         dns_query_complete(q, state);
 }
 
-int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) {
+static int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) {
         _cleanup_(dns_question_unrefp) DnsQuestion *nq = NULL;
         int r;
 
         assert(q);
 
+        q->n_cname_redirects ++;
         if (q->n_cname_redirects > CNAME_MAX)
                 return -ELOOP;
 
@@ -848,14 +882,66 @@ int dns_query_cname_redirect(DnsQuery *q, const DnsResourceRecord *cname) {
         q->question = nq;
         nq = NULL;
 
-        q->n_cname_redirects++;
-
         dns_query_stop(q);
         q->state = DNS_TRANSACTION_NULL;
 
         return 0;
 }
 
+int dns_query_process_cname(DnsQuery *q) {
+        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *cname = NULL;
+        DnsResourceRecord *rr;
+        int r;
+
+        assert(q);
+
+        if (q->state != DNS_TRANSACTION_SUCCESS)
+                return 0;
+
+        DNS_ANSWER_FOREACH(rr, q->answer) {
+
+                r = dns_question_matches_rr(q->question, rr);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        return 0; /* The answer matches directly, no need to follow cnames */
+
+                r = dns_question_matches_cname(q->question, rr);
+                if (r < 0)
+                        return r;
+                if (r > 0 && !cname)
+                        cname = dns_resource_record_ref(rr);
+        }
+
+        if (!cname)
+                return 0; /* No cname to follow */
+
+        if (q->flags & SD_RESOLVED_NO_CNAME)
+                return -ELOOP;
+
+        /* OK, let's actually follow the CNAME */
+        r = dns_query_cname_redirect(q, cname);
+        if (r < 0)
+                return r;
+
+        /* Let's see if the answer can already answer the new
+         * redirected question */
+        DNS_ANSWER_FOREACH(rr, q->answer) {
+                r = dns_question_matches_rr(q->question, rr);
+                if (r < 0)
+                        return r;
+                if (r > 0)
+                        return 0; /* It can answer it, yay! */
+        }
+
+        /* OK, it cannot, let's begin with the new query */
+        r = dns_query_go(q);
+        if (r < 0)
+                return r;
+
+        return 1; /* We return > 0, if we restarted the query for a new cname */
+}
+
 static int on_bus_track(sd_bus_track *t, void *userdata) {
         DnsQuery *q = userdata;