summaryrefslogtreecommitdiff
path: root/src/resolve
diff options
context:
space:
mode:
authorDaniel Mack <daniel@zonque.org>2015-12-01 00:53:42 +0100
committerDaniel Mack <daniel@zonque.org>2015-12-08 16:51:41 +0100
commit7778dffff3d8bd7438fe19a248c16203668324c9 (patch)
tree85d0751d1764287abf73e3ec9376c8331b394004 /src/resolve
parent0afa57e2e7645f3a550729e4daadda419de179c5 (diff)
resolved: add dns_cache_export_to_packet()
This new functions exports cached records of type PTR, SRV and TXT into an existing DnsPacket. This is used in order to fill in known records to mDNS queries, for known answer supression.
Diffstat (limited to 'src/resolve')
-rw-r--r--src/resolve/resolved-dns-cache.c33
-rw-r--r--src/resolve/resolved-dns-cache.h3
-rw-r--r--src/resolve/resolved-dns-rr.h4
-rw-r--r--src/resolve/resolved-dns-transaction.c15
4 files changed, 55 insertions, 0 deletions
diff --git a/src/resolve/resolved-dns-cache.c b/src/resolve/resolved-dns-cache.c
index 2179a61890..6124ff659c 100644
--- a/src/resolve/resolved-dns-cache.c
+++ b/src/resolve/resolved-dns-cache.c
@@ -731,6 +731,39 @@ int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_
return 1;
}
+int dns_cache_export_shared_to_packet(DnsCache *cache, DnsPacket *p) {
+ unsigned ancount = 0;
+ Iterator iterator;
+ DnsCacheItem *i;
+ int r;
+
+ assert(cache);
+
+ HASHMAP_FOREACH(i, cache->by_key, iterator) {
+ DnsCacheItem *j;
+
+ LIST_FOREACH(by_key, j, i) {
+ _cleanup_free_ char *t = NULL;
+
+ if (!j->rr)
+ continue;
+
+ if (!dns_key_is_shared(j->rr->key))
+ continue;
+
+ r = dns_packet_append_rr(p, j->rr, NULL, NULL);
+ if (r < 0)
+ return r;
+
+ ancount ++;
+ }
+ }
+
+ DNS_PACKET_HEADER(p)->ancount = htobe16(ancount);
+
+ return 0;
+}
+
void dns_cache_dump(DnsCache *cache, FILE *f) {
Iterator iterator;
DnsCacheItem *i;
diff --git a/src/resolve/resolved-dns-cache.h b/src/resolve/resolved-dns-cache.h
index 5f91164785..0f28bbe543 100644
--- a/src/resolve/resolved-dns-cache.h
+++ b/src/resolve/resolved-dns-cache.h
@@ -32,6 +32,7 @@ typedef struct DnsCache {
} DnsCache;
#include "resolved-dns-answer.h"
+#include "resolved-dns-packet.h"
#include "resolved-dns-question.h"
#include "resolved-dns-rr.h"
@@ -45,3 +46,5 @@ int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_
void dns_cache_dump(DnsCache *cache, FILE *f);
bool dns_cache_is_empty(DnsCache *cache);
+
+int dns_cache_export_shared_to_packet(DnsCache *cache, DnsPacket *p);
diff --git a/src/resolve/resolved-dns-rr.h b/src/resolve/resolved-dns-rr.h
index 5cbb927681..5c2306ba96 100644
--- a/src/resolve/resolved-dns-rr.h
+++ b/src/resolve/resolved-dns-rr.h
@@ -250,6 +250,10 @@ int dns_resource_key_match_cname(const DnsResourceKey *key, const DnsResourceRec
int dns_resource_key_to_string(const DnsResourceKey *key, char **ret);
DEFINE_TRIVIAL_CLEANUP_FUNC(DnsResourceKey*, dns_resource_key_unref);
+static inline bool dns_key_is_shared(const DnsResourceKey *key) {
+ return IN_SET(key->type, DNS_TYPE_PTR);
+}
+
DnsResourceRecord* dns_resource_record_new(DnsResourceKey *key);
DnsResourceRecord* dns_resource_record_new_full(uint16_t class, uint16_t type, const char *name);
DnsResourceRecord* dns_resource_record_ref(DnsResourceRecord *rr);
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c
index dccb8000a2..90f07e6c4b 100644
--- a/src/resolve/resolved-dns-transaction.c
+++ b/src/resolve/resolved-dns-transaction.c
@@ -24,6 +24,7 @@
#include "dns-domain.h"
#include "fd-util.h"
#include "random-util.h"
+#include "resolved-dns-cache.h"
#include "resolved-dns-transaction.h"
#include "resolved-llmnr.h"
#include "string-table.h"
@@ -733,6 +734,7 @@ static int dns_transaction_prepare_next_attempt(DnsTransaction *t, usec_t ts) {
static int dns_transaction_make_packet_mdns(DnsTransaction *t) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
+ bool add_known_answers = false;
DnsTransaction *other;
unsigned qdcount;
usec_t ts;
@@ -754,6 +756,9 @@ static int dns_transaction_make_packet_mdns(DnsTransaction *t) {
qdcount = 1;
+ if (dns_key_is_shared(t->key))
+ add_known_answers = true;
+
/*
* For mDNS, we want to coalesce as many open queries in pending transactions into one single
* query packet on the wire as possible. To achieve that, we iterate through all pending transactions
@@ -808,11 +813,21 @@ static int dns_transaction_make_packet_mdns(DnsTransaction *t) {
other->next_attempt_after = ts;
qdcount ++;
+
+ if (dns_key_is_shared(other->key))
+ add_known_answers = true;
}
DNS_PACKET_HEADER(p)->qdcount = htobe16(qdcount);
DNS_PACKET_HEADER(p)->id = t->id;
+ /* Append known answer section if we're asking for any shared record */
+ if (add_known_answers) {
+ r = dns_cache_export_shared_to_packet(&t->scope->cache, p);
+ if (r < 0)
+ return r;
+ }
+
t->sent = p;
p = NULL;