diff options
| -rw-r--r-- | src/resolve/resolved-dns-query.c | 33 | ||||
| -rw-r--r-- | src/resolve/resolved-link.c | 11 |
2 files changed, 35 insertions, 9 deletions
diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c index 8570251528..14ae68395f 100644 --- a/src/resolve/resolved-dns-query.c +++ b/src/resolve/resolved-dns-query.c @@ -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; diff --git a/src/resolve/resolved-link.c b/src/resolve/resolved-link.c index 6ac7c5be98..341cb5aea2 100644 --- a/src/resolve/resolved-link.c +++ b/src/resolve/resolved-link.c @@ -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)) { |