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resolved: follow more closely the recommend timeouts and TTLs from the LLMNR spec

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This commit is contained in:
Lennart Poettering
2014-07-30 01:47:48 +02:00
parent d2f47562d5
commit 0c903ae7db
2 changed files with 35 additions and 9 deletions
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src/resolve/resolved-dns-query.c
+29 -4
View File
@@ -24,12 +24,27 @@
#include "resolved-dns-query.h"
#include "resolved-dns-domain.h"
#define TRANSACTION_TIMEOUT_USEC (5 * USEC_PER_SEC)
/* After how much time to repeat classic DNS requests */
#define DNS_TRANSACTION_TIMEOUT_USEC (5 * USEC_PER_SEC)
/* After how much time to repeat LLMNR requests, see RFC 4795 Section 7 */
#define LLMNR_TRANSACTION_TIMEOUT_USEC (1 * USEC_PER_SEC)
/* How long to wait for the query in total */
#define QUERY_TIMEOUT_USEC (30 * USEC_PER_SEC)
#define ATTEMPTS_MAX 8
/* Maximum attempts to send DNS requests, across all DNS servers */
#define DNS_TRANSACTION_ATTEMPTS_MAX 8
/* Maximum attempts to send LLMNR requests, see RFC 4795 Section 2.7 */
#define LLMNR_TRANSACTION_ATTEMPTS_MAX 3
#define CNAME_MAX 8
#define QUERIES_MAX 2048
#define TRANSACTION_TIMEOUT_USEC(p) ((t)->scope->protocol == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_TIMEOUT_USEC : DNS_TRANSACTION_TIMEOUT_USEC)
#define TRANSACTION_ATTEMPTS_MAX(p) ((t)->scope->protocol == DNS_PROTOCOL_LLMNR ? LLMNR_TRANSACTION_ATTEMPTS_MAX : DNS_TRANSACTION_ATTEMPTS_MAX)
static int dns_query_transaction_go(DnsQueryTransaction *t);
DnsQueryTransaction* dns_query_transaction_free(DnsQueryTransaction *t) {
@@ -411,10 +426,13 @@ static int dns_query_make_packet(DnsQueryTransaction *t) {
}
static int dns_query_transaction_go(DnsQueryTransaction *t) {
bool had_stream;
int r;
assert(t);
had_stream = !!t->stream;
dns_query_transaction_stop(t);
log_debug("Beginning transaction on scope %s on %s/%s",
@@ -422,7 +440,14 @@ static int dns_query_transaction_go(DnsQueryTransaction *t) {
t->scope->link ? t->scope->link->name : "*",
t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family));
if (t->n_attempts >= ATTEMPTS_MAX) {
if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t)) {
dns_query_transaction_complete(t, DNS_QUERY_ATTEMPTS_MAX);
return 0;
}
if (t->scope->protocol == DNS_PROTOCOL_LLMNR && had_stream) {
/* If we already tried via a stream, then we don't
* retry on LLMNR. See RFC 4795, Section 2.7. */
dns_query_transaction_complete(t, DNS_QUERY_ATTEMPTS_MAX);
return 0;
}
@@ -482,7 +507,7 @@ static int dns_query_transaction_go(DnsQueryTransaction *t) {
return dns_query_transaction_go(t);
}
r = sd_event_add_time(t->scope->manager->event, &t->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + TRANSACTION_TIMEOUT_USEC, 0, on_transaction_timeout, t);
r = sd_event_add_time(t->scope->manager->event, &t->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + TRANSACTION_TIMEOUT_USEC(t), 0, on_transaction_timeout, t);
if (r < 0)
return r;
src/resolve/resolved-link.c
+6 -5
View File
@@ -25,7 +25,8 @@
#include "strv.h"
#include "resolved-link.h"
#define DEFAULT_TTL (10)
/* RFC 4795 Section 2.8. suggests a TTL of 30s by default */
#define LLMNR_DEFAULT_TTL (30)
static void link_address_add_rrs(LinkAddress *a);
@@ -354,7 +355,7 @@ static void link_address_add_rrs(LinkAddress *a) {
}
a->llmnr_address_rr->a.in_addr = a->in_addr.in;
a->llmnr_address_rr->ttl = DEFAULT_TTL;
a->llmnr_address_rr->ttl = LLMNR_DEFAULT_TTL;
}
if (!a->llmnr_ptr_rr) {
@@ -362,7 +363,7 @@ static void link_address_add_rrs(LinkAddress *a) {
if (r < 0)
goto fail;
a->llmnr_ptr_rr->ttl = DEFAULT_TTL;
a->llmnr_ptr_rr->ttl = LLMNR_DEFAULT_TTL;
}
if (link_address_relevant(a)) {
@@ -397,7 +398,7 @@ static void link_address_add_rrs(LinkAddress *a) {
}
a->llmnr_address_rr->aaaa.in6_addr = a->in_addr.in6;
a->llmnr_address_rr->ttl = DEFAULT_TTL;
a->llmnr_address_rr->ttl = LLMNR_DEFAULT_TTL;
}
if (!a->llmnr_ptr_rr) {
@@ -405,7 +406,7 @@ static void link_address_add_rrs(LinkAddress *a) {
if (r < 0)
goto fail;
a->llmnr_ptr_rr->ttl = DEFAULT_TTL;
a->llmnr_ptr_rr->ttl = LLMNR_DEFAULT_TTL;
}
if (link_address_relevant(a)) {