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resolved: cache - only allow putting a single question key at a time 

Only one key is allowed per transaction now, so let's simplify things and only allow putting
one question key into the cache at a time.
This commit is contained in:
Tom Gundersen 2015-09-04 01:01:27 +02:00
parent 36d9205d66
commit 8e427d9be9
3 changed files with 29 additions and 35 deletions
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60
src/resolve/resolved-dns-cache.c
View File

@ -403,7 +403,7 @@ static int dns_cache_put_negative(
int dns_cache_put(
DnsCache *c,
DnsQuestion *q,
DnsResourceKey *key,
int rcode,
DnsAnswer *answer,
unsigned max_rrs,
@ -411,16 +411,16 @@ int dns_cache_put(
int owner_family,
const union in_addr_union *owner_address) {
DnsResourceRecord *soa = NULL;
unsigned cache_keys, i;
int r;
assert(c);
if (q) {
/* First, if we were passed a question, delete all matching old RRs,
if (key) {
/* First, if we were passed a key, delete all matching old RRs,
* so that we only keep complete by_key in place. */
for (i = 0; i < q->n_keys; i++)
dns_cache_remove(c, q->keys[i]);
dns_cache_remove(c, key);
}
if (!answer)
@ -438,8 +438,8 @@ int dns_cache_put(
cache_keys = answer->n_rrs;
if (q)
cache_keys += q->n_keys;
if (key)
cache_keys ++;
/* Make some space for our new entries */
dns_cache_make_space(c, cache_keys);
@ -454,33 +454,29 @@ int dns_cache_put(
goto fail;
}
if (!q)
if (!key)
return 0;
/* Third, add in negative entries for all keys with no RR */
for (i = 0; i < q->n_keys; i++) {
DnsResourceRecord *soa = NULL;
/* Third, add in negative entries if the key has no RR */
r = dns_answer_contains(answer, key);
if (r < 0)
goto fail;
if (r > 0)
return 0;
r = dns_answer_contains(answer, q->keys[i]);
if (r < 0)
goto fail;
if (r > 0)
continue;
/* See https://tools.ietf.org/html/rfc2308, which
* say that a matching SOA record in the packet
* is used to to enable negative caching. */
/* See https://tools.ietf.org/html/rfc2308, which
* say that a matching SOA record in the packet
* is used to to enable negative caching. */
r = dns_answer_find_soa(answer, key, &soa);
if (r < 0)
goto fail;
if (r == 0)
return 0;
r = dns_answer_find_soa(answer, q->keys[i], &soa);
if (r < 0)
goto fail;
if (r == 0)
continue;
r = dns_cache_put_negative(c, q->keys[i], rcode, timestamp, MIN(soa->soa.minimum, soa->ttl), owner_family, owner_address);
if (r < 0)
goto fail;
}
r = dns_cache_put_negative(c, key, rcode, timestamp, MIN(soa->soa.minimum, soa->ttl), owner_family, owner_address);
if (r < 0)
goto fail;
return 0;
@ -488,10 +484,8 @@ fail:
/* Adding all RRs failed. Let's clean up what we already
* added, just in case */
if (q) {
for (i = 0; i < q->n_keys; i++)
dns_cache_remove(c, q->keys[i]);
}
if (key)
dns_cache_remove(c, key);
for (i = 0; i < answer->n_rrs; i++)
dns_cache_remove(c, answer->items[i].rr->key);

2
src/resolve/resolved-dns-cache.h
View File

@ -39,7 +39,7 @@ typedef struct DnsCache {
void dns_cache_flush(DnsCache *c);
void dns_cache_prune(DnsCache *c);
int dns_cache_put(DnsCache *c, DnsQuestion *q, int rcode, DnsAnswer *answer, unsigned max_rrs, usec_t timestamp, int owner_family, const union in_addr_union *owner_address);
int dns_cache_put(DnsCache *c, DnsResourceKey *key, int rcode, DnsAnswer *answer, unsigned max_rrs, usec_t timestamp, int owner_family, const union in_addr_union *owner_address);
int dns_cache_lookup(DnsCache *c, DnsResourceKey *key, int *rcode, DnsAnswer **answer);
int dns_cache_check_conflicts(DnsCache *cache, DnsResourceRecord *rr, int owner_family, const union in_addr_union *owner_address);

2
src/resolve/resolved-dns-transaction.c
View File

@ -458,7 +458,7 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
}
/* According to RFC 4795, section 2.9. only the RRs from the answer section shall be cached */
dns_cache_put(&t->scope->cache, p->question, DNS_PACKET_RCODE(p), p->answer, DNS_PACKET_ANCOUNT(p), 0, p->family, &p->sender);
dns_cache_put(&t->scope->cache, t->key, DNS_PACKET_RCODE(p), p->answer, DNS_PACKET_ANCOUNT(p), 0, p->family, &p->sender);
if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS)
dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);