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resolved: replace DNS_TRANSACTION_RESOURCES by DNS_TRANSACTION_ERRNO 

Whenever we encounter an OS error we did not expect, we so far put the transaction into DNS_TRANSACTION_RESOURCES
state. Rename this state to DNS_TRANSACTION_ERRNO, and save + propagate the actual system error to the caller. This
should make error messages triggered by system errors much more readable by the user.
This commit is contained in:
Lennart Poettering 2016-01-22 17:22:23 +01:00
parent f25f9e8d60
commit 7cc6ed7ba6
5 changed files with 73 additions and 49 deletions
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4
src/resolve/resolved-bus.c
View File

@ -43,8 +43,8 @@ static int reply_query_state(DnsQuery *q) {
case DNS_TRANSACTION_INVALID_REPLY:
return sd_bus_reply_method_errorf(q->request, BUS_ERROR_INVALID_REPLY, "Received invalid reply");
case DNS_TRANSACTION_RESOURCES:
return sd_bus_reply_method_errorf(q->request, BUS_ERROR_NO_RESOURCES, "Not enough resources");
case DNS_TRANSACTION_ERRNO:
return sd_bus_reply_method_errnof(q->request, q->answer_errno, "Lookup failed due to system error: %m");
case DNS_TRANSACTION_ABORTED:
return sd_bus_reply_method_errorf(q->request, BUS_ERROR_ABORTED, "Query aborted");

31
src/resolve/resolved-dns-query.c
View File

@ -182,7 +182,7 @@ static DnsTransactionState dns_query_candidate_state(DnsQueryCandidate *c) {
assert(c);
if (c->error_code != 0)
return DNS_TRANSACTION_RESOURCES;
return DNS_TRANSACTION_ERRNO;
SET_FOREACH(t, c->transactions, i) {
@ -324,6 +324,7 @@ static void dns_query_reset_answer(DnsQuery *q) {
q->answer = dns_answer_unref(q->answer);
q->answer_rcode = 0;
q->answer_dnssec_result = _DNSSEC_RESULT_INVALID;
q->answer_errno = 0;
q->answer_authenticated = false;
q->answer_protocol = _DNS_PROTOCOL_INVALID;
q->answer_family = AF_UNSPEC;
@ -670,7 +671,10 @@ int dns_query_go(DnsQuery *q) {
if (found == DNS_SCOPE_NO) {
DnsTransactionState state = DNS_TRANSACTION_NO_SERVERS;
dns_query_synthesize_reply(q, &state);
r = dns_query_synthesize_reply(q, &state);
if (r < 0)
return r;
dns_query_complete(q, state);
return 1;
}
@ -748,7 +752,10 @@ static void dns_query_accept(DnsQuery *q, DnsQueryCandidate *c) {
assert(q);
if (!c) {
dns_query_synthesize_reply(q, &state);
r = dns_query_synthesize_reply(q, &state);
if (r < 0)
goto fail;
dns_query_complete(q, state);
return;
}
@ -760,12 +767,11 @@ static void dns_query_accept(DnsQuery *q, DnsQueryCandidate *c) {
case DNS_TRANSACTION_SUCCESS: {
/* We found a successfuly reply, merge it into the answer */
r = dns_answer_extend(&q->answer, t->answer);
if (r < 0) {
dns_query_complete(q, DNS_TRANSACTION_RESOURCES);
return;
}
if (r < 0)
goto fail;
q->answer_rcode = t->answer_rcode;
q->answer_errno = 0;
if (t->answer_authenticated) {
has_authenticated = true;
@ -796,6 +802,7 @@ static void dns_query_accept(DnsQuery *q, DnsQueryCandidate *c) {
q->answer = dns_answer_unref(q->answer);
q->answer_rcode = t->answer_rcode;
q->answer_dnssec_result = t->answer_dnssec_result;
q->answer_errno = t->answer_errno;
state = t->state;
break;
@ -813,8 +820,16 @@ static void dns_query_accept(DnsQuery *q, DnsQueryCandidate *c) {
dns_search_domain_unref(q->answer_search_domain);
q->answer_search_domain = dns_search_domain_ref(c->search_domain);
dns_query_synthesize_reply(q, &state);
r = dns_query_synthesize_reply(q, &state);
if (r < 0)
goto fail;
dns_query_complete(q, state);
return;
fail:
q->answer_errno = -r;
dns_query_complete(q, DNS_TRANSACTION_ERRNO);
}
void dns_query_ready(DnsQuery *q) {

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

@ -83,6 +83,7 @@ struct DnsQuery {
DnsProtocol answer_protocol;
int answer_family;
DnsSearchDomain *answer_search_domain;
int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
/* Bus client information */
sd_bus_message *request;

83
src/resolve/resolved-dns-transaction.c
View File

@ -24,6 +24,7 @@
#include "af-list.h"
#include "alloc-util.h"
#include "dns-domain.h"
#include "errno-list.h"
#include "fd-util.h"
#include "random-util.h"
#include "resolved-dns-cache.h"
@ -43,6 +44,7 @@ static void dns_transaction_reset_answer(DnsTransaction *t) {
t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID;
t->answer_authenticated = false;
t->answer_nsec_ttl = (uint32_t) -1;
t->answer_errno = 0;
}
static void dns_transaction_flush_dnssec_transactions(DnsTransaction *t) {
@ -285,6 +287,7 @@ void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) {
DnsZoneItem *z;
DnsTransaction *d;
Iterator i;
const char *st;
assert(t);
assert(!DNS_TRANSACTION_IS_LIVE(state));
@ -304,13 +307,18 @@ void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) {
* should hence not attempt to access the query or transaction
* after calling this function. */
if (state == DNS_TRANSACTION_ERRNO)
st = errno_to_name(t->answer_errno);
else
st = dns_transaction_state_to_string(state);
log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s).",
t->id,
dns_transaction_key_string(t),
dns_protocol_to_string(t->scope->protocol),
t->scope->link ? t->scope->link->name : "*",
t->scope->family == AF_UNSPEC ? "*" : af_to_name(t->scope->family),
dns_transaction_state_to_string(state),
st,
t->answer_source < 0 ? "none" : dns_transaction_source_to_string(t->answer_source),
t->answer_authenticated ? "authenticated" : "unsigned");
@ -393,8 +401,10 @@ static void dns_transaction_retry(DnsTransaction *t) {
dns_scope_next_dns_server(t->scope);
r = dns_transaction_go(t);
if (r < 0)
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
if (r < 0) {
t->answer_errno = -r;
dns_transaction_complete(t, DNS_TRANSACTION_ERRNO);
}
}
static int dns_transaction_maybe_restart(DnsTransaction *t) {
@ -449,7 +459,8 @@ static int on_stream_complete(DnsStream *s, int error) {
return 0;
}
if (error != 0) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
t->answer_errno = error;
dns_transaction_complete(t, DNS_TRANSACTION_ERRNO);
return 0;
}
@ -664,20 +675,16 @@ static void dns_transaction_process_dnssec(DnsTransaction *t) {
/* Are there ongoing DNSSEC transactions? If so, let's wait for them. */
r = dns_transaction_dnssec_ready(t);
if (r < 0) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return;
}
if (r < 0)
goto fail;
if (r == 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */
return;
/* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better
* restart the lookup immediately. */
r = dns_transaction_maybe_restart(t);
if (r < 0) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return;
}
if (r < 0)
goto fail;
if (r > 0) /* Transaction got restarted... */
return;
@ -688,10 +695,8 @@ static void dns_transaction_process_dnssec(DnsTransaction *t) {
dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY);
return;
}
if (r < 0) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return;
}
if (r < 0)
goto fail;
if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER &&
t->scope->dnssec_mode == DNSSEC_YES) {
@ -719,6 +724,12 @@ static void dns_transaction_process_dnssec(DnsTransaction *t) {
dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);
else
dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE);
return;
fail:
t->answer_errno = -r;
dns_transaction_complete(t, DNS_TRANSACTION_ERRNO);
}
void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
@ -862,10 +873,8 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
if (r < 0) {
/* On LLMNR, if we cannot connect to the host,
* we immediately give up */
if (t->scope->protocol != DNS_PROTOCOL_DNS) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return;
}
if (t->scope->protocol != DNS_PROTOCOL_DNS)
goto fail;
/* On DNS, couldn't send? Try immediately again, with a new server */
dns_transaction_retry(t);
@ -891,10 +900,8 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
/* See if we know things we didn't know before that indicate we better restart the lookup immediately. */
r = dns_transaction_maybe_restart(t);
if (r < 0) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return;
}
if (r < 0)
goto fail;
if (r > 0) /* Transaction got restarted... */
return;
@ -902,10 +909,8 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
/* Only consider responses with equivalent query section to the request */
r = dns_packet_is_reply_for(p, t->key);
if (r < 0) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return;
}
if (r < 0)
goto fail;
if (r == 0) {
dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY);
return;
@ -934,10 +939,8 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
* quickly. */
if (t->state != DNS_TRANSACTION_PENDING)
return;
if (r < 0) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return;
}
if (r < 0)
goto fail;
if (r > 0) {
/* There are DNSSEC transactions pending now. Update the state accordingly. */
t->state = DNS_TRANSACTION_VALIDATING;
@ -948,6 +951,11 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
}
dns_transaction_process_dnssec(t);
return;
fail:
t->answer_errno = -r;
dns_transaction_complete(t, DNS_TRANSACTION_ERRNO);
}
static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
@ -973,7 +981,8 @@ static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *use
return 0;
}
if (r < 0) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
dns_transaction_complete(t, DNS_TRANSACTION_ERRNO);
t->answer_errno = -r;
return 0;
}
@ -1482,10 +1491,8 @@ int dns_transaction_go(DnsTransaction *t) {
return 0;
}
if (r < 0) {
if (t->scope->protocol != DNS_PROTOCOL_DNS) {
dns_transaction_complete(t, DNS_TRANSACTION_RESOURCES);
return 0;
}
if (t->scope->protocol != DNS_PROTOCOL_DNS)
return r;
/* Couldn't send? Try immediately again, with a new server */
dns_scope_next_dns_server(t->scope);
@ -3001,7 +3008,7 @@ static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX]
[DNS_TRANSACTION_TIMEOUT] = "timeout",
[DNS_TRANSACTION_ATTEMPTS_MAX_REACHED] = "attempts-max-reached",
[DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply",
[DNS_TRANSACTION_RESOURCES] = "resources",
[DNS_TRANSACTION_ERRNO] = "errno",
[DNS_TRANSACTION_ABORTED] = "aborted",
[DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed",
[DNS_TRANSACTION_NO_TRUST_ANCHOR] = "no-trust-anchor",

3
src/resolve/resolved-dns-transaction.h
View File

@ -35,7 +35,7 @@ enum DnsTransactionState {
DNS_TRANSACTION_TIMEOUT,
DNS_TRANSACTION_ATTEMPTS_MAX_REACHED,
DNS_TRANSACTION_INVALID_REPLY,
DNS_TRANSACTION_RESOURCES,
DNS_TRANSACTION_ERRNO,
DNS_TRANSACTION_ABORTED,
DNS_TRANSACTION_DNSSEC_FAILED,
DNS_TRANSACTION_NO_TRUST_ANCHOR,
@ -84,6 +84,7 @@ struct DnsTransaction {
DnssecResult answer_dnssec_result;
DnsTransactionSource answer_source;
uint32_t answer_nsec_ttl;
int answer_errno; /* if state is DNS_TRANSACTION_ERRNO */
/* Indicates whether the primary answer is authenticated,
* i.e. whether the RRs from answer which directly match the