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authorLennart Poettering <lennart@poettering.net>2015-12-29 19:27:09 +0100
committerLennart Poettering <lennart@poettering.net>2015-12-29 21:42:10 +0100
commit6af47493de0ef2b66d4c3fbcdd4a2e12fec4bfba (patch)
tree0147fc5ea46ffcdaac2e9bd69ae96e0fa15db7eb
parent6f717d0817573a76c3e586eae02793d8b23a0581 (diff)
resolved: add comments referencing various RFCs to various places
-rw-r--r--src/resolve/resolved-dns-cache.c3
-rw-r--r--src/resolve/resolved-dns-dnssec.c10
-rw-r--r--src/resolve/resolved-dns-rr.c4
-rw-r--r--src/resolve/resolved-dns-rr.h18
4 files changed, 25 insertions, 10 deletions
diff --git a/src/resolve/resolved-dns-cache.c b/src/resolve/resolved-dns-cache.c
index 3193985542..1c7dd56b3b 100644
--- a/src/resolve/resolved-dns-cache.c
+++ b/src/resolve/resolved-dns-cache.c
@@ -26,7 +26,8 @@
#include "resolved-dns-packet.h"
#include "string-util.h"
-/* Never cache more than 4K entries */
+/* Never cache more than 4K entries. RFC 1536, Section 5 suggests to
+ * leave DNS caches unbounded, but that's crazy. */
#define CACHE_MAX 4096
/* We never keep any item longer than 2h in our cache */
diff --git a/src/resolve/resolved-dns-dnssec.c b/src/resolve/resolved-dns-dnssec.c
index a3aa90e98d..3f5226de0d 100644
--- a/src/resolve/resolved-dns-dnssec.c
+++ b/src/resolve/resolved-dns-dnssec.c
@@ -458,7 +458,15 @@ static int dnssec_rrsig_expired(DnsResourceRecord *rrsig, usec_t realtime) {
static int algorithm_to_gcrypt_md(uint8_t algorithm) {
- /* Translates a DNSSEC signature algorithm into a gcrypt digest identifier */
+ /* Translates a DNSSEC signature algorithm into a gcrypt
+ * digest identifier.
+ *
+ * Note that we implement all algorithms listed as "Must
+ * implement" and "Recommended to Implement" in RFC6944. We
+ * don't implement any algorithms that are listed as
+ * "Optional" or "Must Not Implement". Specifically, we do not
+ * implement RSAMD5, DSASHA1, DH, DSA-NSEC3-SHA1, and
+ * GOST-ECC. */
switch (algorithm) {
diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index 89645b064c..274e857586 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -311,6 +311,9 @@ int dns_resource_key_to_string(const DnsResourceKey *key, char **ret) {
const char *c, *t;
char *s;
+ /* If we cannot convert the CLASS/TYPE into a known string,
+ use the format recommended by RFC 3597, Section 5. */
+
c = dns_class_to_string(key->class);
if (!c) {
sprintf(cbuf, "CLASS%u", key->class);
@@ -1021,6 +1024,7 @@ const char *dns_resource_record_to_string(DnsResourceRecord *rr) {
if (!t)
return NULL;
+ /* Format as documented in RFC 3597, Section 5 */
r = asprintf(&s, "%s \\# %zu %s", k, rr->generic.size, t);
if (r < 0)
return NULL;
diff --git a/src/resolve/resolved-dns-rr.h b/src/resolve/resolved-dns-rr.h
index 317be0efbe..cee3978969 100644
--- a/src/resolve/resolved-dns-rr.h
+++ b/src/resolve/resolved-dns-rr.h
@@ -157,6 +157,7 @@ struct DnsResourceRecord {
char *exchange;
} mx;
+ /* https://tools.ietf.org/html/rfc1876 */
struct {
uint8_t version;
uint8_t size;
@@ -167,14 +168,6 @@ struct DnsResourceRecord {
uint32_t altitude;
} loc;
- struct {
- uint16_t key_tag;
- uint8_t algorithm;
- uint8_t digest_type;
- void *digest;
- size_t digest_size;
- } ds;
-
/* https://tools.ietf.org/html/rfc4255#section-3.1 */
struct {
uint8_t algorithm;
@@ -212,6 +205,15 @@ struct DnsResourceRecord {
Bitmap *types;
} nsec;
+ /* https://tools.ietf.org/html/rfc4034#section-5.1 */
+ struct {
+ uint16_t key_tag;
+ uint8_t algorithm;
+ uint8_t digest_type;
+ void *digest;
+ size_t digest_size;
+ } ds;
+
struct {
uint8_t algorithm;
uint8_t flags;