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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.
This commit is contained in:
Lennart Poettering 2016-01-08 02:33:54 +01:00
parent 6a1a5eec43
commit a1a3f73a57
4 changed files with 11 additions and 8 deletions
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3
src/basic/fd-util.h
View File

@ -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)

3
src/resolve/resolved-bus.c
View File

@ -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");

12
src/resolve/resolved-dns-transaction.c
View File

@ -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",

1
src/resolve/resolved-dns-transaction.h
View File

@ -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,