From a1a3f73a57da25dbd158ea71607b7d740b101f49 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 8 Jan 2016 02:33:54 +0100 Subject: [PATCH] resolved: when we get a TCP connection failure, try again Previously, when we couldn't connect to a DNS server via TCP we'd abort the whole transaction using a "connection-failure" state. This change removes that, and counts failed connections as "lost packet" events, so that we switch back to the UDP protocol again. --- src/basic/fd-util.h | 3 +++ src/resolve/resolved-bus.c | 3 --- src/resolve/resolved-dns-transaction.c | 12 ++++++++---- src/resolve/resolved-dns-transaction.h | 1 - 4 files changed, 11 insertions(+), 8 deletions(-) diff --git a/src/basic/fd-util.h b/src/basic/fd-util.h index 5ce1592eeb..973413ff42 100644 --- a/src/basic/fd-util.h +++ b/src/basic/fd-util.h @@ -73,3 +73,6 @@ int same_fd(int a, int b); void cmsg_close_all(struct msghdr *mh); bool fdname_is_valid(const char *s); + +#define ERRNO_IS_DISCONNECT(r) \ + IN_SET(r, ENOTCONN, ECONNRESET, ECONNREFUSED, ECONNABORTED, EPIPE) diff --git a/src/resolve/resolved-bus.c b/src/resolve/resolved-bus.c index 00095463dd..d7295ca39c 100644 --- a/src/resolve/resolved-bus.c +++ b/src/resolve/resolved-bus.c @@ -57,9 +57,6 @@ static int reply_query_state(DnsQuery *q) { case DNS_TRANSACTION_RESOURCES: return sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_RESOURCES, "Not enough resources"); - case DNS_TRANSACTION_CONNECTION_FAILURE: - return sd_bus_reply_method_errorf(q->request, BUS_ERROR_CONNECTION_FAILURE, "DNS server connection failure"); - case DNS_TRANSACTION_ABORTED: return sd_bus_reply_method_errorf(q->request, BUS_ERROR_ABORTED, "Query aborted"); diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c index 78fbb38309..e6e7aeec63 100644 --- a/src/resolve/resolved-dns-transaction.c +++ b/src/resolve/resolved-dns-transaction.c @@ -365,11 +365,16 @@ static int on_stream_complete(DnsStream *s, int error) { t->stream = dns_stream_free(t->stream); - if (IN_SET(error, ENOTCONN, ECONNRESET, ECONNREFUSED, ECONNABORTED, EPIPE)) { - dns_transaction_complete(t, DNS_TRANSACTION_CONNECTION_FAILURE); + if (ERRNO_IS_DISCONNECT(error)) { + usec_t usec; + + log_debug_errno(error, "Connection failure for DNS TCP stream, treating as lost packet: %m"); + assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); + dns_server_packet_lost(t->server, t->current_features, usec - t->start_usec); + + dns_transaction_retry(t); return 0; } - if (error != 0) { dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES); return 0; @@ -2727,7 +2732,6 @@ static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED] = "attempts-max-reached", [DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply", [DNS_TRANSACTION_RESOURCES] = "resources", - [DNS_TRANSACTION_CONNECTION_FAILURE] = "connection-failure", [DNS_TRANSACTION_ABORTED] = "aborted", [DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed", [DNS_TRANSACTION_NO_TRUST_ANCHOR] = "no-trust-anchor", diff --git a/src/resolve/resolved-dns-transaction.h b/src/resolve/resolved-dns-transaction.h index ede33f9547..0df7d01737 100644 --- a/src/resolve/resolved-dns-transaction.h +++ b/src/resolve/resolved-dns-transaction.h @@ -36,7 +36,6 @@ enum DnsTransactionState { DNS_TRANSACTION_ATTEMPTS_MAX_REACHED, DNS_TRANSACTION_INVALID_REPLY, DNS_TRANSACTION_RESOURCES, - DNS_TRANSACTION_CONNECTION_FAILURE, DNS_TRANSACTION_ABORTED, DNS_TRANSACTION_DNSSEC_FAILED, DNS_TRANSACTION_NO_TRUST_ANCHOR,