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fune/netwerk/dns/nsHostResolver.cpp

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/* vim:set ts=4 sw=2 sts=2 et cin: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#if defined(HAVE_RES_NINIT)
# include <sys/types.h>
# include <netinet/in.h>
# include <arpa/inet.h>
# include <arpa/nameser.h>
# include <resolv.h>
# define RES_RETRY_ON_FAILURE
#endif
#include <stdlib.h>
#include <ctime>
#include "nsHostResolver.h"
#include "nsError.h"
#include "nsISupportsBase.h"
#include "nsISupportsUtils.h"
#include "nsIThreadManager.h"
#include "nsComponentManagerUtils.h"
#include "nsNetUtil.h"
#include "nsPrintfCString.h"
#include "nsXPCOMCIDInternal.h"
#include "prthread.h"
#include "prerror.h"
#include "prtime.h"
#include "mozilla/Logging.h"
#include "PLDHashTable.h"
#include "plstr.h"
#include "nsQueryObject.h"
#include "nsURLHelper.h"
#include "nsThreadUtils.h"
#include "nsThreadPool.h"
#include "GetAddrInfo.h"
#include "TRR.h"
#include "TRRQuery.h"
#include "TRRService.h"
#include "ODoHService.h"
#include "mozilla/Atomics.h"
#include "mozilla/HashFunctions.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/Telemetry.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/Preferences.h"
#include "mozilla/StaticPrefs_network.h"
// Put DNSLogging.h at the end to avoid LOG being overwritten by other headers.
#include "DNSLogging.h"
#define IS_ADDR_TYPE(_type) ((_type) == nsIDNSService::RESOLVE_TYPE_DEFAULT)
#define IS_OTHER_TYPE(_type) ((_type) != nsIDNSService::RESOLVE_TYPE_DEFAULT)
using namespace mozilla;
using namespace mozilla::net;
// None of our implementations expose a TTL for negative responses, so we use a
// constant always.
static const unsigned int NEGATIVE_RECORD_LIFETIME = 60;
//----------------------------------------------------------------------------
// Use a persistent thread pool in order to avoid spinning up new threads all
// the time. In particular, thread creation results in a res_init() call from
// libc which is quite expensive.
//
// The pool dynamically grows between 0 and MAX_RESOLVER_THREADS in size. New
// requests go first to an idle thread. If that cannot be found and there are
// fewer than MAX_RESOLVER_THREADS currently in the pool a new thread is created
// for high priority requests. If the new request is at a lower priority a new
// thread will only be created if there are fewer than HighThreadThreshold
// currently outstanding. If a thread cannot be created or an idle thread
// located for the request it is queued.
//
// When the pool is greater than HighThreadThreshold in size a thread will be
// destroyed after ShortIdleTimeoutSeconds of idle time. Smaller pools use
// LongIdleTimeoutSeconds for a timeout period.
#define HighThreadThreshold MAX_RESOLVER_THREADS_FOR_ANY_PRIORITY
#define LongIdleTimeoutSeconds 300 // for threads 1 -> HighThreadThreshold
#define ShortIdleTimeoutSeconds \
60 // for threads HighThreadThreshold+1 -> MAX_RESOLVER_THREADS
static_assert(
HighThreadThreshold <= MAX_RESOLVER_THREADS,
"High Thread Threshold should be less equal Maximum allowed thread");
//----------------------------------------------------------------------------
namespace mozilla::net {
LazyLogModule gHostResolverLog("nsHostResolver");
} // namespace mozilla::net
//----------------------------------------------------------------------------
#if defined(RES_RETRY_ON_FAILURE)
// this class represents the resolver state for a given thread. if we
// encounter a lookup failure, then we can invoke the Reset method on an
// instance of this class to reset the resolver (in case /etc/resolv.conf
// for example changed). this is mainly an issue on GNU systems since glibc
// only reads in /etc/resolv.conf once per thread. it may be an issue on
// other systems as well.
class nsResState {
public:
nsResState()
// initialize mLastReset to the time when this object
// is created. this means that a reset will not occur
// if a thread is too young. the alternative would be
// to initialize this to the beginning of time, so that
// the first failure would cause a reset, but since the
// thread would have just started up, it likely would
// already have current /etc/resolv.conf info.
: mLastReset(PR_IntervalNow()) {}
bool Reset() {
// reset no more than once per second
if (PR_IntervalToSeconds(PR_IntervalNow() - mLastReset) < 1) {
return false;
}
mLastReset = PR_IntervalNow();
auto result = res_ninit(&_res);
LOG(("nsResState::Reset() > 'res_ninit' returned %d", result));
return (result == 0);
}
private:
PRIntervalTime mLastReset;
};
#endif // RES_RETRY_ON_FAILURE
//----------------------------------------------------------------------------
static const char kPrefGetTtl[] = "network.dns.get-ttl";
static const char kPrefNativeIsLocalhost[] = "network.dns.native-is-localhost";
static const char kPrefThreadIdleTime[] =
"network.dns.resolver-thread-extra-idle-time-seconds";
static bool sGetTtlEnabled = false;
mozilla::Atomic<bool, mozilla::Relaxed> gNativeIsLocalhost;
static void DnsPrefChanged(const char* aPref, void* aSelf) {
MOZ_ASSERT(NS_IsMainThread(),
"Should be getting pref changed notification on main thread!");
MOZ_ASSERT(aSelf);
if (!strcmp(aPref, kPrefGetTtl)) {
#ifdef DNSQUERY_AVAILABLE
sGetTtlEnabled = Preferences::GetBool(kPrefGetTtl);
#endif
} else if (!strcmp(aPref, kPrefNativeIsLocalhost)) {
gNativeIsLocalhost = Preferences::GetBool(kPrefNativeIsLocalhost);
}
}
NS_IMPL_ISUPPORTS0(nsHostResolver)
nsHostResolver::nsHostResolver(uint32_t maxCacheEntries,
uint32_t defaultCacheEntryLifetime,
uint32_t defaultGracePeriod)
: mMaxCacheEntries(maxCacheEntries),
mDefaultCacheLifetime(defaultCacheEntryLifetime),
mDefaultGracePeriod(defaultGracePeriod),
mIdleTaskCV(mLock, "nsHostResolver.mIdleTaskCV") {
mCreationTime = PR_Now();
mLongIdleTimeout = TimeDuration::FromSeconds(LongIdleTimeoutSeconds);
mShortIdleTimeout = TimeDuration::FromSeconds(ShortIdleTimeoutSeconds);
}
nsHostResolver::~nsHostResolver() = default;
nsresult nsHostResolver::Init() MOZ_NO_THREAD_SAFETY_ANALYSIS {
MOZ_ASSERT(NS_IsMainThread());
if (NS_FAILED(GetAddrInfoInit())) {
return NS_ERROR_FAILURE;
}
LOG(("nsHostResolver::Init this=%p", this));
mShutdown = false;
mNCS = NetworkConnectivityService::GetSingleton();
// The preferences probably haven't been loaded from the disk yet, so we
// need to register a callback that will set up the experiment once they
// are. We also need to explicitly set a value for the props otherwise the
// callback won't be called.
{
DebugOnly<nsresult> rv = Preferences::RegisterCallbackAndCall(
&DnsPrefChanged, kPrefGetTtl, this);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
"Could not register DNS TTL pref callback.");
rv = Preferences::RegisterCallbackAndCall(&DnsPrefChanged,
kPrefNativeIsLocalhost, this);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
"Could not register DNS pref callback.");
}
#if defined(HAVE_RES_NINIT)
// We want to make sure the system is using the correct resolver settings,
// so we force it to reload those settings whenever we startup a subsequent
// nsHostResolver instance. We assume that there is no reason to do this
// for the first nsHostResolver instance since that is usually created
// during application startup.
static int initCount = 0;
if (initCount++ > 0) {
auto result = res_ninit(&_res);
LOG(("nsHostResolver::Init > 'res_ninit' returned %d", result));
}
#endif
// We can configure the threadpool to keep threads alive for a while after
// the last ThreadFunc task has been executed.
int32_t poolTimeoutSecs = Preferences::GetInt(kPrefThreadIdleTime, 60);
uint32_t poolTimeoutMs;
if (poolTimeoutSecs < 0) {
// This means never shut down the idle threads
poolTimeoutMs = UINT32_MAX;
} else {
// We clamp down the idle time between 0 and one hour.
poolTimeoutMs =
mozilla::clamped<uint32_t>(poolTimeoutSecs * 1000, 0, 3600 * 1000);
}
nsCOMPtr<nsIThreadPool> threadPool = new nsThreadPool();
MOZ_ALWAYS_SUCCEEDS(threadPool->SetThreadLimit(MAX_RESOLVER_THREADS));
MOZ_ALWAYS_SUCCEEDS(threadPool->SetIdleThreadLimit(MAX_RESOLVER_THREADS));
MOZ_ALWAYS_SUCCEEDS(threadPool->SetIdleThreadTimeout(poolTimeoutMs));
MOZ_ALWAYS_SUCCEEDS(
threadPool->SetThreadStackSize(nsIThreadManager::kThreadPoolStackSize));
MOZ_ALWAYS_SUCCEEDS(threadPool->SetName("DNS Resolver"_ns));
mResolverThreads = ToRefPtr(std::move(threadPool));
return NS_OK;
}
void nsHostResolver::ClearPendingQueue(
LinkedList<RefPtr<nsHostRecord>>& aPendingQ) {
// loop through pending queue, erroring out pending lookups.
if (!aPendingQ.isEmpty()) {
for (const RefPtr<nsHostRecord>& rec : aPendingQ) {
rec->Cancel();
if (rec->IsAddrRecord()) {
CompleteLookup(rec, NS_ERROR_ABORT, nullptr, rec->pb, rec->originSuffix,
rec->mTRRSkippedReason, nullptr);
} else {
mozilla::net::TypeRecordResultType empty(Nothing{});
CompleteLookupByType(rec, NS_ERROR_ABORT, empty, 0, rec->pb);
}
}
}
}
//
// FlushCache() is what we call when the network has changed. We must not
// trust names that were resolved before this change. They may resolve
// differently now.
//
// This function removes all existing resolved host entries from the hash.
// Names that are in the pending queues can be left there. Entries in the
// cache that have 'Resolve' set true but not 'OnQueue' are being resolved
// right now, so we need to mark them to get re-resolved on completion!
void nsHostResolver::FlushCache(bool aTrrToo) {
MutexAutoLock lock(mLock);
mQueue.FlushEvictionQ(mRecordDB, lock);
// Refresh the cache entries that are resolving RIGHT now, remove the rest.
for (auto iter = mRecordDB.Iter(); !iter.Done(); iter.Next()) {
nsHostRecord* record = iter.UserData();
// Try to remove the record, or mark it for refresh.
// By-type records are from TRR. We do not need to flush those entry
// when the network has change, because they are not local.
if (record->IsAddrRecord()) {
RefPtr<AddrHostRecord> addrRec = do_QueryObject(record);
MOZ_ASSERT(addrRec);
if (addrRec->RemoveOrRefresh(aTrrToo)) {
mQueue.MaybeRemoveFromQ(record, lock);
LOG(("Removing (%s) Addr record from mRecordDB", record->host.get()));
iter.Remove();
}
} else if (aTrrToo) {
// remove by type records
LOG(("Removing (%s) type record from mRecordDB", record->host.get()));
iter.Remove();
}
}
}
void nsHostResolver::Shutdown() {
LOG(("Shutting down host resolver.\n"));
{
DebugOnly<nsresult> rv =
Preferences::UnregisterCallback(&DnsPrefChanged, kPrefGetTtl, this);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
"Could not unregister DNS TTL pref callback.");
}
LinkedList<RefPtr<nsHostRecord>> pendingQHigh, pendingQMed, pendingQLow,
evictionQ;
{
MutexAutoLock lock(mLock);
mShutdown = true;
if (mNumIdleTasks) {
mIdleTaskCV.NotifyAll();
}
mQueue.ClearAll(
[&](nsHostRecord* aRec) {
mLock.AssertCurrentThreadOwns();
if (aRec->IsAddrRecord()) {
CompleteLookupLocked(aRec, NS_ERROR_ABORT, nullptr, aRec->pb,
aRec->originSuffix, aRec->mTRRSkippedReason,
nullptr, lock);
} else {
mozilla::net::TypeRecordResultType empty(Nothing{});
CompleteLookupByTypeLocked(aRec, NS_ERROR_ABORT, empty, 0, aRec->pb,
lock);
}
},
lock);
for (const auto& data : mRecordDB.Values()) {
data->Cancel();
}
// empty host database
mRecordDB.Clear();
mNCS = nullptr;
}
// Shutdown the resolver threads, but with a timeout of 2 seconds (prefable).
// If the timeout is exceeded, any stuck threads will be leaked.
mResolverThreads->ShutdownWithTimeout(
StaticPrefs::network_dns_resolver_shutdown_timeout_ms());
{
mozilla::DebugOnly<nsresult> rv = GetAddrInfoShutdown();
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "Failed to shutdown GetAddrInfo");
}
}
nsresult nsHostResolver::GetHostRecord(const nsACString& host,
const nsACString& aTrrServer,
uint16_t type, uint16_t flags,
uint16_t af, bool pb,
const nsCString& originSuffix,
nsHostRecord** result) {
MutexAutoLock lock(mLock);
nsHostKey key(host, aTrrServer, type, flags, af, pb, originSuffix);
RefPtr<nsHostRecord> rec =
mRecordDB.LookupOrInsertWith(key, [&] { return InitRecord(key); });
if (rec->IsAddrRecord()) {
RefPtr<AddrHostRecord> addrRec = do_QueryObject(rec);
if (addrRec->addr) {
return NS_ERROR_FAILURE;
}
}
if (rec->mResolving) {
return NS_ERROR_FAILURE;
}
*result = rec.forget().take();
return NS_OK;
}
nsHostRecord* nsHostResolver::InitRecord(const nsHostKey& key) {
if (IS_ADDR_TYPE(key.type)) {
return new AddrHostRecord(key);
}
return new TypeHostRecord(key);
}
already_AddRefed<nsHostRecord> nsHostResolver::InitLoopbackRecord(
const nsHostKey& key, nsresult* aRv) {
MOZ_ASSERT(aRv);
MOZ_ASSERT(IS_ADDR_TYPE(key.type));
*aRv = NS_ERROR_FAILURE;
RefPtr<nsHostRecord> rec = InitRecord(key);
nsTArray<NetAddr> addresses;
NetAddr addr;
if (key.af == PR_AF_INET || key.af == PR_AF_UNSPEC) {
MOZ_RELEASE_ASSERT(NS_SUCCEEDED(addr.InitFromString("127.0.0.1"_ns)));
addresses.AppendElement(addr);
}
if (key.af == PR_AF_INET6 || key.af == PR_AF_UNSPEC) {
MOZ_RELEASE_ASSERT(NS_SUCCEEDED(addr.InitFromString("::1"_ns)));
addresses.AppendElement(addr);
}
RefPtr<AddrInfo> ai =
new AddrInfo(rec->host, DNSResolverType::Native, 0, std::move(addresses));
RefPtr<AddrHostRecord> addrRec = do_QueryObject(rec);
MutexAutoLock lock(addrRec->addr_info_lock);
addrRec->addr_info = ai;
addrRec->SetExpiration(TimeStamp::NowLoRes(), mDefaultCacheLifetime,
mDefaultGracePeriod);
addrRec->negative = false;
*aRv = NS_OK;
return rec.forget();
}
nsresult nsHostResolver::ResolveHost(const nsACString& aHost,
const nsACString& aTrrServer,
int32_t aPort, uint16_t type,
const OriginAttributes& aOriginAttributes,
uint16_t flags, uint16_t af,
nsResolveHostCallback* aCallback) {
nsAutoCString host(aHost);
NS_ENSURE_TRUE(!host.IsEmpty(), NS_ERROR_UNEXPECTED);
nsAutoCString originSuffix;
aOriginAttributes.CreateSuffix(originSuffix);
LOG(("Resolving host [%s]<%s>%s%s type %d. [this=%p]\n", host.get(),
originSuffix.get(), flags & RES_BYPASS_CACHE ? " - bypassing cache" : "",
flags & RES_REFRESH_CACHE ? " - refresh cache" : "", type, this));
// ensure that we are working with a valid hostname before proceeding. see
// bug 304904 for details.
if (!net_IsValidHostName(host)) {
return NS_ERROR_UNKNOWN_HOST;
}
// By-Type requests use only TRR. If TRR is disabled we can return
// immediately.
if (IS_OTHER_TYPE(type) && Mode() == nsIDNSService::MODE_TRROFF) {
return NS_ERROR_UNKNOWN_HOST;
}
// Used to try to parse to an IP address literal.
NetAddr tempAddr;
if (IS_OTHER_TYPE(type) && (NS_SUCCEEDED(tempAddr.InitFromString(host)))) {
// For by-type queries the host cannot be IP literal.
return NS_ERROR_UNKNOWN_HOST;
}
RefPtr<nsResolveHostCallback> callback(aCallback);
// if result is set inside the lock, then we need to issue the
// callback before returning.
RefPtr<nsHostRecord> result;
nsresult status = NS_OK, rv = NS_OK;
{
MutexAutoLock lock(mLock);
if (mShutdown) {
return NS_ERROR_NOT_INITIALIZED;
}
// check to see if there is already an entry for this |host|
// in the hash table. if so, then check to see if we can't
// just reuse the lookup result. otherwise, if there are
// any pending callbacks, then add to pending callbacks queue,
// and return. otherwise, add ourselves as first pending
// callback, and proceed to do the lookup.
Maybe<nsCString> originHost;
if (StaticPrefs::network_dns_port_prefixed_qname_https_rr() &&
type == nsIDNSService::RESOLVE_TYPE_HTTPSSVC && aPort != -1 &&
aPort != 443) {
originHost = Some(host);
host = nsPrintfCString("_%d._https.%s", aPort, host.get());
LOG((" Using port prefixed host name [%s]", host.get()));
}
bool excludedFromTRR = false;
if (TRRService::Get() && TRRService::Get()->IsExcludedFromTRR(host)) {
flags |= RES_DISABLE_TRR;
excludedFromTRR = true;
if (!aTrrServer.IsEmpty()) {
return NS_ERROR_UNKNOWN_HOST;
}
}
nsHostKey key(host, aTrrServer, type, flags, af,
(aOriginAttributes.mPrivateBrowsingId > 0), originSuffix);
// Check if we have a localhost domain, if so hardcode to loopback
if (IS_ADDR_TYPE(type) && IsLoopbackHostname(host)) {
nsresult rv;
RefPtr<nsHostRecord> result = InitLoopbackRecord(key, &rv);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
MOZ_ASSERT(result);
aCallback->OnResolveHostComplete(this, result, NS_OK);
return NS_OK;
}
RefPtr<nsHostRecord> rec =
mRecordDB.LookupOrInsertWith(key, [&] { return InitRecord(key); });
RefPtr<AddrHostRecord> addrRec = do_QueryObject(rec);
MOZ_ASSERT(rec, "Record should not be null");
MOZ_ASSERT((IS_ADDR_TYPE(type) && rec->IsAddrRecord() && addrRec) ||
(IS_OTHER_TYPE(type) && !rec->IsAddrRecord()));
if (IS_OTHER_TYPE(type) && originHost) {
RefPtr<TypeHostRecord> typeRec = do_QueryObject(rec);
typeRec->mOriginHost = std::move(originHost);
}
if (excludedFromTRR) {
rec->RecordReason(TRRSkippedReason::TRR_EXCLUDED);
}
if (!(flags & RES_BYPASS_CACHE) &&
rec->HasUsableResult(TimeStamp::NowLoRes(), flags)) {
result = FromCache(rec, host, type, status, lock);
} else if (addrRec && addrRec->addr) {
// if the host name is an IP address literal and has been
// parsed, go ahead and use it.
LOG((" Using cached address for IP Literal [%s].\n", host.get()));
result = FromCachedIPLiteral(rec);
} else if (addrRec && NS_SUCCEEDED(tempAddr.InitFromString(host))) {
// try parsing the host name as an IP address literal to short
// circuit full host resolution. (this is necessary on some
// platforms like Win9x. see bug 219376 for more details.)
LOG((" Host is IP Literal [%s].\n", host.get()));
result = FromIPLiteral(addrRec, tempAddr);
} else if (mQueue.PendingCount() >= MAX_NON_PRIORITY_REQUESTS &&
!IsHighPriority(flags) && !rec->mResolving) {
LOG(
(" Lookup queue full: dropping %s priority request for "
"host [%s].\n",
IsMediumPriority(flags) ? "medium" : "low", host.get()));
if (IS_ADDR_TYPE(type)) {
Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2, METHOD_OVERFLOW);
}
// This is a lower priority request and we are swamped, so refuse it.
rv = NS_ERROR_DNS_LOOKUP_QUEUE_FULL;
// Check if the offline flag is set.
} else if (flags & RES_OFFLINE) {
LOG((" Offline request for host [%s]; ignoring.\n", host.get()));
rv = NS_ERROR_OFFLINE;
// We do not have a valid result till here.
// A/AAAA request can check for an alternative entry like AF_UNSPEC.
// Otherwise we need to start a new query.
} else if (!rec->mResolving) {
result =
FromUnspecEntry(rec, host, aTrrServer, originSuffix, type, flags, af,
aOriginAttributes.mPrivateBrowsingId > 0, status);
// If this is a by-type request or if no valid record was found
// in the cache or this is an AF_UNSPEC request, then start a
// new lookup.
if (!result) {
LOG((" No usable record in cache for host [%s] type %d.", host.get(),
type));
if (flags & RES_REFRESH_CACHE) {
rec->Invalidate();
}
// Add callback to the list of pending callbacks.
rec->mCallbacks.insertBack(callback);
rec->flags = flags;
rv = NameLookup(rec, lock);
if (IS_ADDR_TYPE(type)) {
Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2,
METHOD_NETWORK_FIRST);
}
if (NS_FAILED(rv) && callback->isInList()) {
callback->remove();
} else {
LOG(
(" DNS lookup for host [%s] blocking "
"pending 'getaddrinfo' or trr query: "
"callback [%p]",
host.get(), callback.get()));
}
}
} else {
LOG(
(" Host [%s] is being resolved. Appending callback "
"[%p].",
host.get(), callback.get()));
rec->mCallbacks.insertBack(callback);
// Only A/AAAA records are place in a queue. The queues are for
// the native resolver, therefore by-type request are never put
// into a queue.
if (addrRec && addrRec->onQueue()) {
Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2,
METHOD_NETWORK_SHARED);
// Consider the case where we are on a pending queue of
// lower priority than the request is being made at.
// In that case we should upgrade to the higher queue.
if (IsHighPriority(flags) && !IsHighPriority(rec->flags)) {
// Move from (low|med) to high.
mQueue.MoveToAnotherPendingQ(rec, flags, lock);
rec->flags = flags;
ConditionallyCreateThread(rec);
} else if (IsMediumPriority(flags) && IsLowPriority(rec->flags)) {
// Move from low to med.
mQueue.MoveToAnotherPendingQ(rec, flags, lock);
rec->flags = flags;
mIdleTaskCV.Notify();
}
}
}
if (result && callback->isInList()) {
callback->remove();
}
} // lock
if (result) {
callback->OnResolveHostComplete(this, result, status);
}
return rv;
}
already_AddRefed<nsHostRecord> nsHostResolver::FromCache(
nsHostRecord* aRec, const nsACString& aHost, uint16_t aType,
nsresult& aStatus, const MutexAutoLock& aLock) {
LOG((" Using cached record for host [%s].\n",
nsPromiseFlatCString(aHost).get()));
// put reference to host record on stack...
RefPtr<nsHostRecord> result = aRec;
if (IS_ADDR_TYPE(aType)) {
Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2, METHOD_HIT);
}
// For entries that are in the grace period
// or all cached negative entries, use the cache but start a new
// lookup in the background
ConditionallyRefreshRecord(aRec, aHost, aLock);
if (aRec->negative) {
LOG((" Negative cache entry for host [%s].\n",
nsPromiseFlatCString(aHost).get()));
if (IS_ADDR_TYPE(aType)) {
Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2, METHOD_NEGATIVE_HIT);
}
aStatus = NS_ERROR_UNKNOWN_HOST;
}
return result.forget();
}
already_AddRefed<nsHostRecord> nsHostResolver::FromCachedIPLiteral(
nsHostRecord* aRec) {
Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2, METHOD_LITERAL);
RefPtr<nsHostRecord> result = aRec;
return result.forget();
}
already_AddRefed<nsHostRecord> nsHostResolver::FromIPLiteral(
AddrHostRecord* aAddrRec, const NetAddr& aAddr) {
// ok, just copy the result into the host record, and be
// done with it! ;-)
aAddrRec->addr = MakeUnique<NetAddr>(aAddr);
Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2, METHOD_LITERAL);
// put reference to host record on stack...
RefPtr<nsHostRecord> result = aAddrRec;
return result.forget();
}
already_AddRefed<nsHostRecord> nsHostResolver::FromUnspecEntry(
nsHostRecord* aRec, const nsACString& aHost, const nsACString& aTrrServer,
const nsACString& aOriginSuffix, uint16_t aType, uint16_t aFlags,
uint16_t af, bool aPb, nsresult& aStatus) {
RefPtr<nsHostRecord> result = nullptr;
// If this is an IPV4 or IPV6 specific request, check if there is
// an AF_UNSPEC entry we can use. Otherwise, hit the resolver...
RefPtr<AddrHostRecord> addrRec = do_QueryObject(aRec);
if (addrRec && !(aFlags & RES_BYPASS_CACHE) &&
((af == PR_AF_INET) || (af == PR_AF_INET6))) {
// Check for an AF_UNSPEC entry.
const nsHostKey unspecKey(aHost, aTrrServer,
nsIDNSService::RESOLVE_TYPE_DEFAULT, aFlags,
PR_AF_UNSPEC, aPb, aOriginSuffix);
RefPtr<nsHostRecord> unspecRec = mRecordDB.Get(unspecKey);
TimeStamp now = TimeStamp::NowLoRes();
if (unspecRec && unspecRec->HasUsableResult(now, aFlags)) {
MOZ_ASSERT(unspecRec->IsAddrRecord());
RefPtr<AddrHostRecord> addrUnspecRec = do_QueryObject(unspecRec);
MOZ_ASSERT(addrUnspecRec);
MOZ_ASSERT(addrUnspecRec->addr_info || addrUnspecRec->negative,
"Entry should be resolved or negative.");
LOG((" Trying AF_UNSPEC entry for host [%s] af: %s.\n",
PromiseFlatCString(aHost).get(),
(af == PR_AF_INET) ? "AF_INET" : "AF_INET6"));
// We need to lock in case any other thread is reading
// addr_info.
MutexAutoLock lock(addrRec->addr_info_lock);
addrRec->addr_info = nullptr;
addrRec->addr_info_gencnt++;
if (unspecRec->negative) {
aRec->negative = unspecRec->negative;
aRec->CopyExpirationTimesAndFlagsFrom(unspecRec);
} else if (addrUnspecRec->addr_info) {
MutexAutoLock lock(addrUnspecRec->addr_info_lock);
if (addrUnspecRec->addr_info) {
// Search for any valid address in the AF_UNSPEC entry
// in the cache (not blocklisted and from the right
// family).
nsTArray<NetAddr> addresses;
for (const auto& addr : addrUnspecRec->addr_info->Addresses()) {
if ((af == addr.inet.family) &&
!addrUnspecRec->Blocklisted(&addr)) {
addresses.AppendElement(addr);
}
}
if (!addresses.IsEmpty()) {
addrRec->addr_info = new AddrInfo(
addrUnspecRec->addr_info->Hostname(),
addrUnspecRec->addr_info->CanonicalHostname(),
addrUnspecRec->addr_info->ResolverType(),
addrUnspecRec->addr_info->TRRType(), std::move(addresses));
addrRec->addr_info_gencnt++;
aRec->CopyExpirationTimesAndFlagsFrom(unspecRec);
}
}
}
// Now check if we have a new record.
if (aRec->HasUsableResult(now, aFlags)) {
result = aRec;
if (aRec->negative) {
aStatus = NS_ERROR_UNKNOWN_HOST;
}
Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2, METHOD_HIT);
ConditionallyRefreshRecord(aRec, aHost, lock);
} else if (af == PR_AF_INET6) {
// For AF_INET6, a new lookup means another AF_UNSPEC
// lookup. We have already iterated through the
// AF_UNSPEC addresses, so we mark this record as
// negative.
LOG(
(" No AF_INET6 in AF_UNSPEC entry: "
"host [%s] unknown host.",
nsPromiseFlatCString(aHost).get()));
result = aRec;
aRec->negative = true;
aStatus = NS_ERROR_UNKNOWN_HOST;
Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2,
METHOD_NEGATIVE_HIT);
}
}
}
return result.forget();
}
void nsHostResolver::DetachCallback(
const nsACString& host, const nsACString& aTrrServer, uint16_t aType,
const OriginAttributes& aOriginAttributes, uint16_t flags, uint16_t af,
nsResolveHostCallback* aCallback, nsresult status) {
RefPtr<nsHostRecord> rec;
RefPtr<nsResolveHostCallback> callback(aCallback);
{
MutexAutoLock lock(mLock);
nsAutoCString originSuffix;
aOriginAttributes.CreateSuffix(originSuffix);
nsHostKey key(host, aTrrServer, aType, flags, af,
(aOriginAttributes.mPrivateBrowsingId > 0), originSuffix);
RefPtr<nsHostRecord> entry = mRecordDB.Get(key);
if (entry) {
// walk list looking for |callback|... we cannot assume
// that it will be there!
for (nsResolveHostCallback* c : entry->mCallbacks) {
if (c == callback) {
rec = entry;
c->remove();
break;
}
}
}
}
// complete callback with the given status code; this would only be done if
// the record was in the process of being resolved.
if (rec) {
callback->OnResolveHostComplete(this, rec, status);
}
}
nsresult nsHostResolver::ConditionallyCreateThread(nsHostRecord* rec) {
if (mNumIdleTasks) {
// wake up idle tasks to process this lookup
mIdleTaskCV.Notify();
} else if ((mActiveTaskCount < HighThreadThreshold) ||
(IsHighPriority(rec->flags) &&
mActiveTaskCount < MAX_RESOLVER_THREADS)) {
nsCOMPtr<nsIRunnable> event = mozilla::NewRunnableMethod(
"nsHostResolver::ThreadFunc", this, &nsHostResolver::ThreadFunc);
mActiveTaskCount++;
nsresult rv =
mResolverThreads->Dispatch(event, nsIEventTarget::DISPATCH_NORMAL);
if (NS_FAILED(rv)) {
mActiveTaskCount--;
}
} else {
LOG((" Unable to find a thread for looking up host [%s].\n",
rec->host.get()));
}
return NS_OK;
}
nsresult nsHostResolver::TrrLookup_unlocked(nsHostRecord* rec, TRR* pushedTRR) {
MutexAutoLock lock(mLock);
return TrrLookup(rec, lock, pushedTRR);
}
void nsHostResolver::MaybeRenewHostRecord(nsHostRecord* aRec) {
MutexAutoLock lock(mLock);
MaybeRenewHostRecordLocked(aRec, lock);
}
void nsHostResolver::MaybeRenewHostRecordLocked(nsHostRecord* aRec,
const MutexAutoLock& aLock) {
mQueue.MaybeRenewHostRecord(aRec, aLock);
}
bool nsHostResolver::TRRServiceEnabledForRecord(nsHostRecord* aRec) {
MOZ_ASSERT(aRec, "Record must not be empty");
MOZ_ASSERT(aRec->mEffectiveTRRMode != nsIRequest::TRR_DEFAULT_MODE,
"effective TRR mode must be computed before this call");
if (!TRRService::Get()) {
aRec->RecordReason(TRRSkippedReason::TRR_NO_GSERVICE);
return false;
}
// We always try custom resolvers.
if (!aRec->mTrrServer.IsEmpty()) {
return true;
}
nsIRequest::TRRMode reqMode = aRec->mEffectiveTRRMode;
if (TRRService::Get()->Enabled(reqMode)) {
return true;
}
if (NS_IsOffline()) {
// If we are in the NOT_CONFIRMED state _because_ we lack connectivity,
// then we should report that the browser is offline instead.
aRec->RecordReason(TRRSkippedReason::TRR_IS_OFFLINE);
return false;
}
auto hasConnectivity = [this]() -> bool {
mLock.AssertCurrentThreadOwns();
if (!mNCS) {
return true;
}
nsINetworkConnectivityService::ConnectivityState ipv4 = mNCS->GetIPv4();
nsINetworkConnectivityService::ConnectivityState ipv6 = mNCS->GetIPv6();
if (ipv4 == nsINetworkConnectivityService::OK ||
ipv6 == nsINetworkConnectivityService::OK) {
return true;
}
if (ipv4 == nsINetworkConnectivityService::UNKNOWN ||
ipv6 == nsINetworkConnectivityService::UNKNOWN) {
// One of the checks hasn't completed yet. Optimistically assume we'll
// have network connectivity.
return true;
}
return false;
};
if (!hasConnectivity()) {
aRec->RecordReason(TRRSkippedReason::TRR_NO_CONNECTIVITY);
return false;
}
bool isConfirmed = TRRService::Get()->IsConfirmed();
if (!isConfirmed) {
aRec->RecordReason(TRRSkippedReason::TRR_NOT_CONFIRMED);
}
return isConfirmed;
}
// returns error if no TRR resolve is issued
// it is impt this is not called while a native lookup is going on
nsresult nsHostResolver::TrrLookup(nsHostRecord* aRec,
const MutexAutoLock& aLock, TRR* pushedTRR) {
if (Mode() == nsIDNSService::MODE_TRROFF ||
StaticPrefs::network_dns_disabled()) {
return NS_ERROR_UNKNOWN_HOST;
}
LOG(("TrrLookup host:%s af:%" PRId16, aRec->host.get(), aRec->af));
RefPtr<nsHostRecord> rec(aRec);
mLock.AssertCurrentThreadOwns();
RefPtr<AddrHostRecord> addrRec;
RefPtr<TypeHostRecord> typeRec;
if (rec->IsAddrRecord()) {
addrRec = do_QueryObject(rec);
MOZ_ASSERT(addrRec);
} else {
typeRec = do_QueryObject(rec);
MOZ_ASSERT(typeRec);
}
MOZ_ASSERT(!rec->mResolving);
if (!TRRServiceEnabledForRecord(aRec)) {
return NS_ERROR_UNKNOWN_HOST;
}
MaybeRenewHostRecordLocked(rec, aLock);
RefPtr<TRRQuery> query = new TRRQuery(this, rec);
bool useODoH = gODoHService->Enabled() &&
!((rec->flags & nsIDNSService::RESOLVE_DISABLE_ODOH));
nsresult rv = query->DispatchLookup(pushedTRR, useODoH);
if (NS_FAILED(rv)) {
rec->RecordReason(TRRSkippedReason::TRR_DID_NOT_MAKE_QUERY);
return rv;
}
{
auto lock = rec->mTRRQuery.Lock();
MOZ_ASSERT(!lock.ref(), "TRR already in progress");
lock.ref() = query;
}
rec->mResolving++;
rec->mTrrAttempts++;
return NS_OK;
}
nsresult nsHostResolver::NativeLookup(nsHostRecord* aRec,
const MutexAutoLock& aLock) {
if (StaticPrefs::network_dns_disabled()) {
return NS_ERROR_UNKNOWN_HOST;
}
LOG(("NativeLookup host:%s af:%" PRId16, aRec->host.get(), aRec->af));
// Only A/AAAA request are resolve natively.
MOZ_ASSERT(aRec->IsAddrRecord());
mLock.AssertCurrentThreadOwns();
RefPtr<nsHostRecord> rec(aRec);
RefPtr<AddrHostRecord> addrRec;
addrRec = do_QueryObject(rec);
MOZ_ASSERT(addrRec);
addrRec->mNativeStart = TimeStamp::Now();
// Add rec to one of the pending queues, possibly removing it from mEvictionQ.
MaybeRenewHostRecordLocked(aRec, aLock);
mQueue.InsertRecord(rec, rec->flags, aLock);
addrRec->StoreNative(true);
addrRec->StoreNativeUsed(true);
addrRec->mResolving++;
nsresult rv = ConditionallyCreateThread(rec);
LOG((" DNS thread counters: total=%d any-live=%d idle=%d pending=%d\n",
static_cast<uint32_t>(mActiveTaskCount),
static_cast<uint32_t>(mActiveAnyThreadCount),
static_cast<uint32_t>(mNumIdleTasks), mQueue.PendingCount()));
return rv;
}
// static
nsIDNSService::ResolverMode nsHostResolver::Mode() {
if (TRRService::Get()) {
return TRRService::Get()->Mode();
}
// If we don't have a TRR service just return MODE_TRROFF so we don't make
// any TRR requests by mistake.
return nsIDNSService::MODE_TRROFF;
}
nsIRequest::TRRMode nsHostRecord::TRRMode() {
return nsIDNSService::GetTRRModeFromFlags(flags);
}
// static
void nsHostResolver::ComputeEffectiveTRRMode(nsHostRecord* aRec) {
nsIDNSService::ResolverMode resolverMode = nsHostResolver::Mode();
nsIRequest::TRRMode requestMode = aRec->TRRMode();
// For domains that are excluded from TRR or when parental control is enabled,
// we fallback to NativeLookup. This happens even in MODE_TRRONLY. By default
// localhost and local are excluded (so we cover *.local hosts) See the
// network.trr.excluded-domains pref.
if (!TRRService::Get()) {
aRec->RecordReason(TRRSkippedReason::TRR_NO_GSERVICE);
aRec->mEffectiveTRRMode = requestMode;
return;
}
if (!aRec->mTrrServer.IsEmpty()) {
aRec->mEffectiveTRRMode = nsIRequest::TRR_ONLY_MODE;
return;
}
if (TRRService::Get()->IsExcludedFromTRR(aRec->host)) {
aRec->RecordReason(TRRSkippedReason::TRR_EXCLUDED);
aRec->mEffectiveTRRMode = nsIRequest::TRR_DISABLED_MODE;
return;
}
if (StaticPrefs::network_dns_skipTRR_when_parental_control_enabled() &&
TRRService::Get()->ParentalControlEnabled()) {
aRec->RecordReason(TRRSkippedReason::TRR_PARENTAL_CONTROL);
aRec->mEffectiveTRRMode = nsIRequest::TRR_DISABLED_MODE;
return;
}
if (resolverMode == nsIDNSService::MODE_TRROFF) {
aRec->RecordReason(TRRSkippedReason::TRR_OFF_EXPLICIT);
aRec->mEffectiveTRRMode = nsIRequest::TRR_DISABLED_MODE;
return;
}
if (requestMode == nsIRequest::TRR_DISABLED_MODE) {
aRec->RecordReason(TRRSkippedReason::TRR_REQ_MODE_DISABLED);
aRec->mEffectiveTRRMode = nsIRequest::TRR_DISABLED_MODE;
return;
}
if ((requestMode == nsIRequest::TRR_DEFAULT_MODE &&
resolverMode == nsIDNSService::MODE_NATIVEONLY)) {
aRec->RecordReason(TRRSkippedReason::TRR_MODE_NOT_ENABLED);
aRec->mEffectiveTRRMode = nsIRequest::TRR_DISABLED_MODE;
return;
}
if (requestMode == nsIRequest::TRR_DEFAULT_MODE &&
resolverMode == nsIDNSService::MODE_TRRFIRST) {
aRec->mEffectiveTRRMode = nsIRequest::TRR_FIRST_MODE;
return;
}
if (requestMode == nsIRequest::TRR_DEFAULT_MODE &&
resolverMode == nsIDNSService::MODE_TRRONLY) {
aRec->mEffectiveTRRMode = nsIRequest::TRR_ONLY_MODE;
return;
}
aRec->mEffectiveTRRMode = requestMode;
}
// Kick-off a name resolve operation, using native resolver and/or TRR
nsresult nsHostResolver::NameLookup(nsHostRecord* rec,
const mozilla::MutexAutoLock& aLock) {
LOG(("NameLookup host:%s af:%" PRId16, rec->host.get(), rec->af));
mLock.AssertCurrentThreadOwns();
if (rec->flags & RES_IP_HINT) {
LOG(("Skip lookup if RES_IP_HINT is set\n"));
return NS_ERROR_UNKNOWN_HOST;
}
nsresult rv = NS_ERROR_UNKNOWN_HOST;
if (rec->mResolving) {
LOG(("NameLookup %s while already resolving\n", rec->host.get()));
return NS_OK;
}
// Make sure we reset the reason each time we attempt to do a new lookup
// so we don't wrongly report the reason for the previous one.
rec->Reset();
ComputeEffectiveTRRMode(rec);
if (!rec->mTrrServer.IsEmpty()) {
LOG(("NameLookup: %s use trr:%s", rec->host.get(), rec->mTrrServer.get()));
if (rec->mEffectiveTRRMode != nsIRequest::TRR_ONLY_MODE) {
return NS_ERROR_UNKNOWN_HOST;
}
if (rec->flags & RES_DISABLE_TRR) {
LOG(("TRR with server and DISABLE_TRR flag. Returning error."));
return NS_ERROR_UNKNOWN_HOST;
}
return TrrLookup(rec, aLock);
}
LOG(("NameLookup: %s effectiveTRRmode: %d flags: %X", rec->host.get(),
rec->mEffectiveTRRMode, rec->flags));
if (rec->flags & RES_DISABLE_TRR) {
rec->RecordReason(TRRSkippedReason::TRR_DISABLED_FLAG);
}
bool serviceNotReady = !TRRServiceEnabledForRecord(rec);
if (rec->mEffectiveTRRMode != nsIRequest::TRR_DISABLED_MODE &&
!((rec->flags & RES_DISABLE_TRR)) && !serviceNotReady) {
rv = TrrLookup(rec, aLock);
}
if (rec->mEffectiveTRRMode == nsIRequest::TRR_DISABLED_MODE ||
(rec->mEffectiveTRRMode == nsIRequest::TRR_FIRST_MODE &&
(rec->flags & RES_DISABLE_TRR || serviceNotReady || NS_FAILED(rv)))) {
if (!rec->IsAddrRecord()) {
return rv;
}
#ifdef DEBUG
// If we use this branch then the mTRRUsed flag should not be set
// Even if we did call TrrLookup above, the fact that it failed sync-ly
// means that we didn't actually succeed in opening the channel.
RefPtr<AddrHostRecord> addrRec = do_QueryObject(rec);
MOZ_ASSERT(addrRec && addrRec->mResolverType == DNSResolverType::Native);
#endif
rv = NativeLookup(rec, aLock);
}
return rv;
}
nsresult nsHostResolver::ConditionallyRefreshRecord(
nsHostRecord* rec, const nsACString& host, const MutexAutoLock& aLock) {
if ((rec->CheckExpiration(TimeStamp::NowLoRes()) != nsHostRecord::EXP_VALID ||
rec->negative) &&
!rec->mResolving && rec->RefreshForNegativeResponse()) {
LOG((" Using %s cache entry for host [%s] but starting async renewal.",
rec->negative ? "negative" : "positive", host.BeginReading()));
NameLookup(rec, aLock);
if (rec->IsAddrRecord() && !rec->negative) {
// negative entries are constantly being refreshed, only
// track positive grace period induced renewals
Telemetry::Accumulate(Telemetry::DNS_LOOKUP_METHOD2, METHOD_RENEWAL);
}
}
return NS_OK;
}
bool nsHostResolver::GetHostToLookup(AddrHostRecord** result) {
bool timedOut = false;
TimeDuration timeout;
TimeStamp epoch, now;
MutexAutoLock lock(mLock);
timeout = (mNumIdleTasks >= HighThreadThreshold) ? mShortIdleTimeout
: mLongIdleTimeout;
epoch = TimeStamp::Now();
while (!mShutdown) {
// remove next record from Q; hand over owning reference. Check high, then
// med, then low
#define SET_GET_TTL(var, val) (var)->StoreGetTtl(sGetTtlEnabled && (val))
RefPtr<AddrHostRecord> addrRec = mQueue.Dequeue(true, lock);
if (addrRec) {
SET_GET_TTL(addrRec, false);
addrRec.forget(result);
return true;
}
if (mActiveAnyThreadCount < HighThreadThreshold) {
addrRec = mQueue.Dequeue(false, lock);
if (addrRec) {
MOZ_ASSERT(IsMediumPriority(addrRec->flags) ||
IsLowPriority(addrRec->flags));
mActiveAnyThreadCount++;
addrRec->StoreUsingAnyThread(true);
SET_GET_TTL(addrRec, true);
addrRec.forget(result);
return true;
}
}
// Determining timeout is racy, so allow one cycle through checking the
// queues before exiting.
if (timedOut) {
break;
}
// wait for one or more of the following to occur:
// (1) the pending queue has a host record to process
// (2) the shutdown flag has been set
// (3) the thread has been idle for too long
mNumIdleTasks++;
mIdleTaskCV.Wait(timeout);
mNumIdleTasks--;
now = TimeStamp::Now();
if (now - epoch >= timeout) {
timedOut = true;
} else {
// It is possible that CondVar::Wait() was interrupted and returned
// early, in which case we will loop back and re-enter it. In that
// case we want to do so with the new timeout reduced to reflect
// time already spent waiting.
timeout -= now - epoch;
epoch = now;
}
}
// tell thread to exit...
return false;
}
void nsHostResolver::PrepareRecordExpirationAddrRecord(
AddrHostRecord* rec) const {
// NOTE: rec->addr_info_lock is already held by parent
MOZ_ASSERT(((bool)rec->addr_info) != rec->negative);
mLock.AssertCurrentThreadOwns();
if (!rec->addr_info) {
rec->SetExpiration(TimeStamp::NowLoRes(), NEGATIVE_RECORD_LIFETIME, 0);
LOG(("Caching host [%s] negative record for %u seconds.\n", rec->host.get(),
NEGATIVE_RECORD_LIFETIME));
return;
}
unsigned int lifetime = mDefaultCacheLifetime;
unsigned int grace = mDefaultGracePeriod;
unsigned int ttl = mDefaultCacheLifetime;
if (sGetTtlEnabled || rec->addr_info->IsTRROrODoH()) {
if (rec->addr_info && rec->addr_info->TTL() != AddrInfo::NO_TTL_DATA) {
ttl = rec->addr_info->TTL();
}
lifetime = ttl;
grace = 0;
}
rec->SetExpiration(TimeStamp::NowLoRes(), lifetime, grace);
LOG(("Caching host [%s] record for %u seconds (grace %d).", rec->host.get(),
lifetime, grace));
}
static bool different_rrset(AddrInfo* rrset1, AddrInfo* rrset2) {
if (!rrset1 || !rrset2) {
return true;
}
LOG(("different_rrset %s\n", rrset1->Hostname().get()));
if (rrset1->ResolverType() != rrset2->ResolverType()) {
return true;
}
if (rrset1->TRRType() != rrset2->TRRType()) {
return true;
}
if (rrset1->Addresses().Length() != rrset2->Addresses().Length()) {
LOG(("different_rrset true due to length change\n"));
return true;
}
nsTArray<NetAddr> orderedSet1 = rrset1->Addresses().Clone();
nsTArray<NetAddr> orderedSet2 = rrset2->Addresses().Clone();
orderedSet1.Sort();
orderedSet2.Sort();
bool eq = orderedSet1 == orderedSet2;
if (!eq) {
LOG(("different_rrset true due to content change\n"));
} else {
LOG(("different_rrset false\n"));
}
return !eq;
}
void nsHostResolver::AddToEvictionQ(nsHostRecord* rec,
const MutexAutoLock& aLock) {
mQueue.AddToEvictionQ(rec, mMaxCacheEntries, mRecordDB, aLock);
}
// After a first lookup attempt with TRR in mode 2, we may:
// - If network.trr.retry_on_recoverable_errors is false, retry with native.
// - If network.trr.retry_on_recoverable_errors is true:
// - Retry with native if the first attempt failed because we got NXDOMAIN, an
// unreachable address (TRR_DISABLED_FLAG), or we skipped TRR because
// Confirmation failed.
// - Trigger a "RetryTRR" Confirmation which will start a fresh
// connection for TRR, and then retry the lookup with TRR.
// - If the second attempt failed, fallback to native if
// network.trr.strict_native_fallback is false.
// Returns true if we retried with either TRR or Native.
bool nsHostResolver::MaybeRetryTRRLookup(
AddrHostRecord* aAddrRec, nsresult aFirstAttemptStatus,
TRRSkippedReason aFirstAttemptSkipReason, const MutexAutoLock& aLock) {
if (NS_SUCCEEDED(aFirstAttemptStatus) ||
aAddrRec->mEffectiveTRRMode != nsIRequest::TRR_FIRST_MODE ||
aFirstAttemptStatus == NS_ERROR_DEFINITIVE_UNKNOWN_HOST) {
return false;
}
MOZ_ASSERT(!aAddrRec->mResolving);
if (!StaticPrefs::network_trr_retry_on_recoverable_errors()) {
LOG(("nsHostResolver::MaybeRetryTRRLookup retrying with native"));
return NS_SUCCEEDED(NativeLookup(aAddrRec, aLock));
}
if (IsFailedConfirmationOrNoConnectivity(aFirstAttemptSkipReason) ||
IsNonRecoverableTRRSkipReason(aFirstAttemptSkipReason) ||
IsBlockedTRRRequest(aFirstAttemptSkipReason)) {
LOG(
("nsHostResolver::MaybeRetryTRRLookup retrying with native in strict "
"mode, skip reason was %d",
static_cast<uint32_t>(aFirstAttemptSkipReason)));
return NS_SUCCEEDED(NativeLookup(aAddrRec, aLock));
}
if (aAddrRec->mTrrAttempts > 1) {
if (!StaticPrefs::network_trr_strict_native_fallback()) {
LOG(
("nsHostResolver::MaybeRetryTRRLookup retry failed. Using "
"native."));
return NS_SUCCEEDED(NativeLookup(aAddrRec, aLock));
}
if (aFirstAttemptSkipReason == TRRSkippedReason::TRR_TIMEOUT &&
StaticPrefs::network_trr_strict_native_fallback_allow_timeouts()) {
LOG(
("nsHostResolver::MaybeRetryTRRLookup retry timed out. Using "
"native."));
return NS_SUCCEEDED(NativeLookup(aAddrRec, aLock));
}
LOG(("nsHostResolver::MaybeRetryTRRLookup mTrrAttempts>1, not retrying."));
return false;
}
LOG(
("nsHostResolver::MaybeRetryTRRLookup triggering Confirmation and "
"retrying with TRR, skip reason was %d",
static_cast<uint32_t>(aFirstAttemptSkipReason)));
TRRService::Get()->RetryTRRConfirm();
{
// Clear out the old query
auto trrQuery = aAddrRec->mTRRQuery.Lock();
trrQuery.ref() = nullptr;
}
if (NS_SUCCEEDED(TrrLookup(aAddrRec, aLock, nullptr /* pushedTRR */))) {
aAddrRec->NotifyRetryingTrr();
return true;
}
return false;
}
//
// CompleteLookup() checks if the resolving should be redone and if so it
// returns LOOKUP_RESOLVEAGAIN, but only if 'status' is not NS_ERROR_ABORT.
nsHostResolver::LookupStatus nsHostResolver::CompleteLookup(
nsHostRecord* rec, nsresult status, AddrInfo* aNewRRSet, bool pb,
const nsACString& aOriginsuffix, TRRSkippedReason aReason,
mozilla::net::TRR* aTRRRequest) {
MutexAutoLock lock(mLock);
return CompleteLookupLocked(rec, status, aNewRRSet, pb, aOriginsuffix,
aReason, aTRRRequest, lock);
}
nsHostResolver::LookupStatus nsHostResolver::CompleteLookupLocked(
nsHostRecord* rec, nsresult status, AddrInfo* aNewRRSet, bool pb,
const nsACString& aOriginsuffix, TRRSkippedReason aReason,
mozilla::net::TRR* aTRRRequest, const mozilla::MutexAutoLock& aLock) {
MOZ_ASSERT(rec);
MOZ_ASSERT(rec->pb == pb);
MOZ_ASSERT(rec->IsAddrRecord());
RefPtr<AddrHostRecord> addrRec = do_QueryObject(rec);
MOZ_ASSERT(addrRec);
RefPtr<AddrInfo> newRRSet(aNewRRSet);
MOZ_ASSERT(NS_FAILED(status) || newRRSet->Addresses().Length() > 0);
DNSResolverType type =
newRRSet ? newRRSet->ResolverType() : DNSResolverType::Native;
if (NS_FAILED(status)) {
newRRSet = nullptr;
}
if (addrRec->LoadResolveAgain() && (status != NS_ERROR_ABORT) &&
type == DNSResolverType::Native) {
LOG(("nsHostResolver record %p resolve again due to flushcache\n",
addrRec.get()));
addrRec->StoreResolveAgain(false);
return LOOKUP_RESOLVEAGAIN;
}
MOZ_ASSERT(addrRec->mResolving);
addrRec->mResolving--;
LOG((
"nsHostResolver::CompleteLookup %s %p %X resolver=%d stillResolving=%d\n",
addrRec->host.get(), aNewRRSet, (unsigned int)status, (int)type,
int(addrRec->mResolving)));
if (type != DNSResolverType::Native) {
if (NS_FAILED(status) && status != NS_ERROR_UNKNOWN_HOST &&
status != NS_ERROR_DEFINITIVE_UNKNOWN_HOST) {
// the errors are not failed resolves, that means
// something else failed, consider this as *TRR not used*
// for actually trying to resolve the host
addrRec->mResolverType = DNSResolverType::Native;
}
if (NS_FAILED(status)) {
if (aReason != TRRSkippedReason::TRR_UNSET) {
addrRec->RecordReason(aReason);
} else {
// Unknown failed reason.
addrRec->RecordReason(TRRSkippedReason::TRR_FAILED);
}
} else {
addrRec->mTRRSuccess = true;
addrRec->RecordReason(TRRSkippedReason::TRR_OK);
}
if (MaybeRetryTRRLookup(addrRec, status, aReason, aLock)) {
MOZ_ASSERT(addrRec->mResolving);
return LOOKUP_OK;
}
if (!addrRec->mTRRSuccess) {
// no TRR success
newRRSet = nullptr;
}
if (NS_FAILED(status)) {
// This is the error that consumers expect.
status = NS_ERROR_UNKNOWN_HOST;
}
} else { // native resolve completed
if (addrRec->LoadUsingAnyThread()) {
mActiveAnyThreadCount--;
addrRec->StoreUsingAnyThread(false);
}
addrRec->mNativeSuccess = static_cast<bool>(newRRSet);
if (addrRec->mNativeSuccess) {
addrRec->mNativeDuration = TimeStamp::Now() - addrRec->mNativeStart;
}
}
addrRec->OnCompleteLookup();
// update record fields. We might have a addrRec->addr_info already if a
// previous lookup result expired and we're reresolving it or we get
// a late second TRR response.
if (!mShutdown) {
MutexAutoLock lock(addrRec->addr_info_lock);
RefPtr<AddrInfo> old_addr_info;
if (different_rrset(addrRec->addr_info, newRRSet)) {
LOG(("nsHostResolver record %p new gencnt\n", addrRec.get()));
old_addr_info = addrRec->addr_info;
addrRec->addr_info = std::move(newRRSet);
addrRec->addr_info_gencnt++;
} else {
if (addrRec->addr_info && newRRSet) {
auto builder = addrRec->addr_info->Build();
builder.SetTTL(newRRSet->TTL());
// Update trr timings
builder.SetTrrFetchDuration(newRRSet->GetTrrFetchDuration());
builder.SetTrrFetchDurationNetworkOnly(
newRRSet->GetTrrFetchDurationNetworkOnly());
addrRec->addr_info = builder.Finish();
}
old_addr_info = std::move(newRRSet);
}
addrRec->negative = !addrRec->addr_info;
PrepareRecordExpirationAddrRecord(addrRec);
}
if (LOG_ENABLED()) {
MutexAutoLock lock(addrRec->addr_info_lock);
if (addrRec->addr_info) {
for (const auto& elem : addrRec->addr_info->Addresses()) {
char buf[128];
elem.ToStringBuffer(buf, sizeof(buf));
LOG(("CompleteLookup: %s has %s\n", addrRec->host.get(), buf));
}
} else {
LOG(("CompleteLookup: %s has NO address\n", addrRec->host.get()));
}
}
// get the list of pending callbacks for this lookup, and notify
// them that the lookup is complete.
mozilla::LinkedList<RefPtr<nsResolveHostCallback>> cbs =
std::move(rec->mCallbacks);
LOG(("nsHostResolver record %p calling back dns users status:%X\n",
addrRec.get(), int(status)));
for (nsResolveHostCallback* c = cbs.getFirst(); c;
c = c->removeAndGetNext()) {
c->OnResolveHostComplete(this, rec, status);
}
if (!addrRec->mResolving && !mShutdown) {
{
auto trrQuery = addrRec->mTRRQuery.Lock();
if (trrQuery.ref()) {
addrRec->mTrrDuration = trrQuery.ref()->Duration();
}
trrQuery.ref() = nullptr;
}
addrRec->ResolveComplete();
AddToEvictionQ(rec, aLock);
}
#ifdef DNSQUERY_AVAILABLE
// Unless the result is from TRR, resolve again to get TTL
bool hasNativeResult = false;
{
MutexAutoLock lock(addrRec->addr_info_lock);
if (addrRec->addr_info && !addrRec->addr_info->IsTRROrODoH()) {
hasNativeResult = true;
}
}
if (hasNativeResult && !mShutdown && !addrRec->LoadGetTtl() &&
!rec->mResolving && sGetTtlEnabled) {
LOG(("Issuing second async lookup for TTL for host [%s].",
addrRec->host.get()));
addrRec->flags = (addrRec->flags & ~RES_PRIORITY_MEDIUM) | RES_PRIORITY_LOW;
DebugOnly<nsresult> rv = NativeLookup(rec, aLock);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv),
"Could not issue second async lookup for TTL.");
}
#endif
return LOOKUP_OK;
}
nsHostResolver::LookupStatus nsHostResolver::CompleteLookupByType(
nsHostRecord* rec, nsresult status,
mozilla::net::TypeRecordResultType& aResult, uint32_t aTtl, bool pb) {
MutexAutoLock lock(mLock);
return CompleteLookupByTypeLocked(rec, status, aResult, aTtl, pb, lock);
}
nsHostResolver::LookupStatus nsHostResolver::CompleteLookupByTypeLocked(
nsHostRecord* rec, nsresult status,
mozilla::net::TypeRecordResultType& aResult, uint32_t aTtl, bool pb,
const mozilla::MutexAutoLock& aLock) {
MOZ_ASSERT(rec);
MOZ_ASSERT(rec->pb == pb);
MOZ_ASSERT(!rec->IsAddrRecord());
RefPtr<TypeHostRecord> typeRec = do_QueryObject(rec);
MOZ_ASSERT(typeRec);
MOZ_ASSERT(typeRec->mResolving);
typeRec->mResolving--;
{
auto lock = rec->mTRRQuery.Lock();
lock.ref() = nullptr;
}
uint32_t duration = static_cast<uint32_t>(
(TimeStamp::Now() - typeRec->mStart).ToMilliseconds());
if (NS_FAILED(status)) {
LOG(("nsHostResolver::CompleteLookupByType record %p [%s] status %x\n",
typeRec.get(), typeRec->host.get(), (unsigned int)status));
typeRec->SetExpiration(
TimeStamp::NowLoRes(),
StaticPrefs::network_dns_negative_ttl_for_type_record(), 0);
MOZ_ASSERT(aResult.is<TypeRecordEmpty>());
status = NS_ERROR_UNKNOWN_HOST;
typeRec->negative = true;
Telemetry::Accumulate(Telemetry::DNS_BY_TYPE_FAILED_LOOKUP_TIME, duration);
} else {
size_t recordCount = 0;
if (aResult.is<TypeRecordTxt>()) {
recordCount = aResult.as<TypeRecordTxt>().Length();
} else if (aResult.is<TypeRecordHTTPSSVC>()) {
recordCount = aResult.as<TypeRecordHTTPSSVC>().Length();
}
LOG(
("nsHostResolver::CompleteLookupByType record %p [%s], number of "
"records %zu\n",
typeRec.get(), typeRec->host.get(), recordCount));
MutexAutoLock typeLock(typeRec->mResultsLock);
typeRec->mResults = aResult;
typeRec->SetExpiration(TimeStamp::NowLoRes(), aTtl, mDefaultGracePeriod);
typeRec->negative = false;
Telemetry::Accumulate(Telemetry::DNS_BY_TYPE_SUCCEEDED_LOOKUP_TIME,
duration);
}
mozilla::LinkedList<RefPtr<nsResolveHostCallback>> cbs =
std::move(typeRec->mCallbacks);
LOG(
("nsHostResolver::CompleteLookupByType record %p calling back dns "
"users\n",
typeRec.get()));
for (nsResolveHostCallback* c = cbs.getFirst(); c;
c = c->removeAndGetNext()) {
c->OnResolveHostComplete(this, rec, status);
}
AddToEvictionQ(rec, aLock);
return LOOKUP_OK;
}
void nsHostResolver::CancelAsyncRequest(
const nsACString& host, const nsACString& aTrrServer, uint16_t aType,
const OriginAttributes& aOriginAttributes, uint16_t flags, uint16_t af,
nsIDNSListener* aListener, nsresult status)
{
MutexAutoLock lock(mLock);
nsAutoCString originSuffix;
aOriginAttributes.CreateSuffix(originSuffix);
// Lookup the host record associated with host, flags & address family
nsHostKey key(host, aTrrServer, aType, flags, af,
(aOriginAttributes.mPrivateBrowsingId > 0), originSuffix);
RefPtr<nsHostRecord> rec = mRecordDB.Get(key);
if (!rec) {
return;
}
for (RefPtr<nsResolveHostCallback> c : rec->mCallbacks) {
if (c->EqualsAsyncListener(aListener)) {
c->remove();
c->OnResolveHostComplete(this, rec.get(), status);
break;
}
}
// If there are no more callbacks, remove the hash table entry
if (rec->mCallbacks.isEmpty()) {
mRecordDB.Remove(*static_cast<nsHostKey*>(rec.get()));
// If record is on a Queue, remove it
mQueue.MaybeRemoveFromQ(rec, lock);
}
}
size_t nsHostResolver::SizeOfIncludingThis(MallocSizeOf mallocSizeOf) const {
MutexAutoLock lock(mLock);
size_t n = mallocSizeOf(this);
n += mRecordDB.ShallowSizeOfExcludingThis(mallocSizeOf);
for (const auto& entry : mRecordDB.Values()) {
n += entry->SizeOfIncludingThis(mallocSizeOf);
}
// The following fields aren't measured.
// - mHighQ, mMediumQ, mLowQ, mEvictionQ, because they just point to
// nsHostRecords that also pointed to by entries |mRecordDB|, and
// measured when |mRecordDB| is measured.
return n;
}
void nsHostResolver::ThreadFunc() {
LOG(("DNS lookup thread - starting execution.\n"));
#if defined(RES_RETRY_ON_FAILURE)
nsResState rs;
#endif
RefPtr<AddrHostRecord> rec;
RefPtr<AddrInfo> ai;
do {
if (!rec) {
RefPtr<AddrHostRecord> tmpRec;
if (!GetHostToLookup(getter_AddRefs(tmpRec))) {
break; // thread shutdown signal
}
// GetHostToLookup() returns an owning reference
MOZ_ASSERT(tmpRec);
rec.swap(tmpRec);
}
LOG1(("DNS lookup thread - Calling getaddrinfo for host [%s].\n",
rec->host.get()));
TimeStamp startTime = TimeStamp::Now();
bool getTtl = rec->LoadGetTtl();
TimeDuration inQueue = startTime - rec->mNativeStart;
uint32_t ms = static_cast<uint32_t>(inQueue.ToMilliseconds());
Telemetry::Accumulate(Telemetry::DNS_NATIVE_QUEUING, ms);
nsresult status =
GetAddrInfo(rec->host, rec->af, rec->flags, getter_AddRefs(ai), getTtl);
#if defined(RES_RETRY_ON_FAILURE)
if (NS_FAILED(status) && rs.Reset()) {
status = GetAddrInfo(rec->host, rec->af, rec->flags, getter_AddRefs(ai),
getTtl);
}
#endif
{ // obtain lock to check shutdown and manage inter-module telemetry
MutexAutoLock lock(mLock);
if (!mShutdown) {
TimeDuration elapsed = TimeStamp::Now() - startTime;
uint32_t millis = static_cast<uint32_t>(elapsed.ToMilliseconds());
if (NS_SUCCEEDED(status)) {
Telemetry::HistogramID histogramID;
if (!rec->addr_info_gencnt) {
// Time for initial lookup.
histogramID = Telemetry::DNS_LOOKUP_TIME;
} else if (!getTtl) {
// Time for renewal; categorized by expiration strategy.
histogramID = Telemetry::DNS_RENEWAL_TIME;
} else {
// Time to get TTL; categorized by expiration strategy.
histogramID = Telemetry::DNS_RENEWAL_TIME_FOR_TTL;
}
Telemetry::Accumulate(histogramID, millis);
} else {
Telemetry::Accumulate(Telemetry::DNS_FAILED_LOOKUP_TIME, millis);
}
}
}
LOG1(("DNS lookup thread - lookup completed for host [%s]: %s.\n",
rec->host.get(), ai ? "success" : "failure: unknown host"));
if (LOOKUP_RESOLVEAGAIN ==
CompleteLookup(rec, status, ai, rec->pb, rec->originSuffix,
rec->mTRRSkippedReason, nullptr)) {
// leave 'rec' assigned and loop to make a renewed host resolve
LOG(("DNS lookup thread - Re-resolving host [%s].\n", rec->host.get()));
} else {
rec = nullptr;
}
} while (true);
MutexAutoLock lock(mLock);
mActiveTaskCount--;
LOG(("DNS lookup thread - queue empty, task finished.\n"));
}
void nsHostResolver::SetCacheLimits(uint32_t aMaxCacheEntries,
uint32_t aDefaultCacheEntryLifetime,
uint32_t aDefaultGracePeriod) {
MutexAutoLock lock(mLock);
mMaxCacheEntries = aMaxCacheEntries;
mDefaultCacheLifetime = aDefaultCacheEntryLifetime;
mDefaultGracePeriod = aDefaultGracePeriod;
}
nsresult nsHostResolver::Create(uint32_t maxCacheEntries,
uint32_t defaultCacheEntryLifetime,
uint32_t defaultGracePeriod,
nsHostResolver** result) {
RefPtr<nsHostResolver> res = new nsHostResolver(
maxCacheEntries, defaultCacheEntryLifetime, defaultGracePeriod);
nsresult rv = res->Init();
if (NS_FAILED(rv)) {
return rv;
}
res.forget(result);
return NS_OK;
}
void nsHostResolver::GetDNSCacheEntries(nsTArray<DNSCacheEntries>* args) {
MutexAutoLock lock(mLock);
for (const auto& recordEntry : mRecordDB) {
// We don't pay attention to address literals, only resolved domains.
// Also require a host.
nsHostRecord* rec = recordEntry.GetWeak();
MOZ_ASSERT(rec, "rec should never be null here!");
if (!rec) {
continue;
}
// For now we only show A/AAAA records.
if (!rec->IsAddrRecord()) {
continue;
}
RefPtr<AddrHostRecord> addrRec = do_QueryObject(rec);
MOZ_ASSERT(addrRec);
if (!addrRec || !addrRec->addr_info) {
continue;
}
DNSCacheEntries info;
info.hostname = rec->host;
info.family = rec->af;
info.expiration =
(int64_t)(rec->mValidEnd - TimeStamp::NowLoRes()).ToSeconds();
if (info.expiration <= 0) {
// We only need valid DNS cache entries
continue;
}
{
MutexAutoLock lock(addrRec->addr_info_lock);
for (const auto& addr : addrRec->addr_info->Addresses()) {
char buf[kIPv6CStrBufSize];
if (addr.ToStringBuffer(buf, sizeof(buf))) {
info.hostaddr.AppendElement(buf);
}
}
info.TRR = addrRec->addr_info->IsTRROrODoH();
}
info.originAttributesSuffix = recordEntry.GetKey().originSuffix;
info.flags = nsPrintfCString("%u|0x%x|%u|%d|%s", rec->type, rec->flags,
rec->af, rec->pb, rec->mTrrServer.get());
args->AppendElement(std::move(info));
}
}
#undef LOG
#undef LOG_ENABLED
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