The Tor Browser: netwerk/dns/nsDNSService2.cpp@ca08bd8f51b2 (annotated)

netwerk/dns/nsDNSService2.cpp@ca08bd8f51b2 (annotated)

netwerk/dns/nsDNSService2.cpp

Wed, 31 Dec 2014 06:55:46 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:55:46 +0100
changeset 1: ca08bd8f51b2
permissions: -rw-r--r--

Added tag TORBROWSER_REPLICA for changeset 6474c204b198

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* vim: set sw=4 ts=8 et tw=80 : */
 /* 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/. */
 #include "nsDNSService2.h"
 #include "nsIDNSRecord.h"
 #include "nsIDNSListener.h"
 #include "nsICancelable.h"
 #include "nsIPrefService.h"
 #include "nsIPrefBranch.h"
 #include "nsIServiceManager.h"
 #include "nsIXPConnect.h"
 #include "nsProxyRelease.h"
 #include "nsReadableUtils.h"
 #include "nsString.h"
 #include "nsAutoPtr.h"
 #include "nsNetCID.h"
 #include "nsError.h"
 #include "nsDNSPrefetch.h"
 #include "nsThreadUtils.h"
 #include "nsIProtocolProxyService.h"
 #include "prsystem.h"
 #include "prnetdb.h"
 #include "prmon.h"
 #include "prio.h"
 #include "plstr.h"
 #include "nsIOService.h"
 #include "nsCharSeparatedTokenizer.h"
 #include "nsNetAddr.h"
 #include "nsProxyRelease.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/VisualEventTracer.h"
 #include "mozilla/net/NeckoCommon.h"
 #include "mozilla/net/ChildDNSService.h"
 #include "mozilla/net/DNSListenerProxy.h"
 using namespace mozilla;
 using namespace mozilla::net;
 static const char kPrefDnsCacheEntries[]     = "network.dnsCacheEntries";
 static const char kPrefDnsCacheExpiration[]  = "network.dnsCacheExpiration";
 static const char kPrefDnsCacheGrace[]       = "network.dnsCacheExpirationGracePeriod";
 static const char kPrefIPv4OnlyDomains[]     = "network.dns.ipv4OnlyDomains";
 static const char kPrefDisableIPv6[]         = "network.dns.disableIPv6";
 static const char kPrefDisablePrefetch[]     = "network.dns.disablePrefetch";
 static const char kPrefDnsLocalDomains[]     = "network.dns.localDomains";
 static const char kPrefDnsNotifyResolution[] = "network.dns.notifyResolution";
 //-----------------------------------------------------------------------------
 class nsDNSRecord : public nsIDNSRecord
 {
 public:
     NS_DECL_THREADSAFE_ISUPPORTS
     NS_DECL_NSIDNSRECORD
     nsDNSRecord(nsHostRecord *hostRecord)
         : mHostRecord(hostRecord)
         , mIter(nullptr)
         , mIterGenCnt(-1)
         , mDone(false) {}
 private:
     virtual ~nsDNSRecord() {}
     nsRefPtr<nsHostRecord>  mHostRecord;
     NetAddrElement         *mIter;
     int                     mIterGenCnt; // the generation count of
                                          // mHostRecord->addr_info when we
                                          // start iterating
     bool                    mDone;
 };
 NS_IMPL_ISUPPORTS(nsDNSRecord, nsIDNSRecord)
 NS_IMETHODIMP
 nsDNSRecord::GetCanonicalName(nsACString &result)
 {
     // this method should only be called if we have a CNAME
     NS_ENSURE_TRUE(mHostRecord->flags & nsHostResolver::RES_CANON_NAME,
                    NS_ERROR_NOT_AVAILABLE);
     // if the record is for an IP address literal, then the canonical
     // host name is the IP address literal.
     const char *cname;
     {
         MutexAutoLock lock(mHostRecord->addr_info_lock);
         if (mHostRecord->addr_info)
             cname = mHostRecord->addr_info->mCanonicalName ?
                 mHostRecord->addr_info->mCanonicalName :
                 mHostRecord->addr_info->mHostName;
         else
             cname = mHostRecord->host;
         result.Assign(cname);
     }
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSRecord::GetNextAddr(uint16_t port, NetAddr *addr)
 {
     if (mDone) {
         return NS_ERROR_NOT_AVAILABLE;
     }
     mHostRecord->addr_info_lock.Lock();
     if (mHostRecord->addr_info) {
         if (mIterGenCnt != mHostRecord->addr_info_gencnt) {
             // mHostRecord->addr_info has changed, restart the iteration.
             mIter = nullptr;
             mIterGenCnt = mHostRecord->addr_info_gencnt;
         }
         bool startedFresh = !mIter;
         do {
             if (!mIter) {
                 mIter = mHostRecord->addr_info->mAddresses.getFirst();
             } else {
                 mIter = mIter->getNext();
             }
         }
         while (mIter && mHostRecord->Blacklisted(&mIter->mAddress));
         if (!mIter && startedFresh) {
             // If everything was blacklisted we want to reset the blacklist (and
             // likely relearn it) and return the first address. That is better
             // than nothing.
             mHostRecord->ResetBlacklist();
             mIter = mHostRecord->addr_info->mAddresses.getFirst();
         }
         if (mIter) {
             memcpy(addr, &mIter->mAddress, sizeof(NetAddr));
         }
         mHostRecord->addr_info_lock.Unlock();
         if (!mIter) {
             mDone = true;
             return NS_ERROR_NOT_AVAILABLE;
         }
     }
     else {
         mHostRecord->addr_info_lock.Unlock();
         if (!mHostRecord->addr) {
             // Both mHostRecord->addr_info and mHostRecord->addr are null.
             // This can happen if mHostRecord->addr_info expired and the
             // attempt to reresolve it failed.
             return NS_ERROR_NOT_AVAILABLE;
         }
         memcpy(addr, mHostRecord->addr, sizeof(NetAddr));
         mDone = true;
     }
     // set given port
     port = htons(port);
     if (addr->raw.family == AF_INET) {
         addr->inet.port = port;
     }
     else if (addr->raw.family == AF_INET6) {
         addr->inet6.port = port;
     }
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSRecord::GetScriptableNextAddr(uint16_t port, nsINetAddr * *result)
 {
     NetAddr addr;
     nsresult rv = GetNextAddr(port, &addr);
     if (NS_FAILED(rv)) return rv;
     NS_ADDREF(*result = new nsNetAddr(&addr));
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSRecord::GetNextAddrAsString(nsACString &result)
 {
     NetAddr addr;
     nsresult rv = GetNextAddr(0, &addr);
     if (NS_FAILED(rv)) return rv;
     char buf[kIPv6CStrBufSize];
     if (NetAddrToString(&addr, buf, sizeof(buf))) {
         result.Assign(buf);
         return NS_OK;
     }
     NS_ERROR("NetAddrToString failed unexpectedly");
     return NS_ERROR_FAILURE; // conversion failed for some reason
 }
 NS_IMETHODIMP
 nsDNSRecord::HasMore(bool *result)
 {
     if (mDone) {
         *result = false;
         return NS_OK;
     }
     NetAddrElement *iterCopy = mIter;
     NetAddr addr;
     *result = NS_SUCCEEDED(GetNextAddr(0, &addr));
     mIter = iterCopy;
     mDone = false;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSRecord::Rewind()
 {
     mIter = nullptr;
     mIterGenCnt = -1;
     mDone = false;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSRecord::ReportUnusable(uint16_t aPort)
 {
     // right now we don't use the port in the blacklist
     MutexAutoLock lock(mHostRecord->addr_info_lock);
     // Check that we are using a real addr_info (as opposed to a single
     // constant address), and that the generation count is valid. Otherwise,
     // ignore the report.
     if (mHostRecord->addr_info &&
         mIterGenCnt == mHostRecord->addr_info_gencnt &&
         mIter) {
         mHostRecord->ReportUnusable(&mIter->mAddress);
     }
     return NS_OK;
 }
 //-----------------------------------------------------------------------------
 class nsDNSAsyncRequest MOZ_FINAL : public nsResolveHostCallback
                                   , public nsICancelable
 {
 public:
     NS_DECL_THREADSAFE_ISUPPORTS
     NS_DECL_NSICANCELABLE
     nsDNSAsyncRequest(nsHostResolver   *res,
                       const nsACString &host,
                       nsIDNSListener   *listener,
                       uint16_t          flags,
                       uint16_t          af)
         : mResolver(res)
         , mHost(host)
         , mListener(listener)
         , mFlags(flags)
         , mAF(af) {}
     ~nsDNSAsyncRequest() {}
     void OnLookupComplete(nsHostResolver *, nsHostRecord *, nsresult);
     // Returns TRUE if the DNS listener arg is the same as the member listener
     // Used in Cancellations to remove DNS requests associated with a
     // particular hostname and nsIDNSListener
     bool EqualsAsyncListener(nsIDNSListener *aListener);
     size_t SizeOfIncludingThis(mozilla::MallocSizeOf) const;
     nsRefPtr<nsHostResolver> mResolver;
     nsCString                mHost; // hostname we're resolving
     nsCOMPtr<nsIDNSListener> mListener;
     uint16_t                 mFlags;
     uint16_t                 mAF;
 };
 void
 nsDNSAsyncRequest::OnLookupComplete(nsHostResolver *resolver,
                                     nsHostRecord   *hostRecord,
                                     nsresult        status)
 {
     // need to have an owning ref when we issue the callback to enable
     // the caller to be able to addref/release multiple times without
     // destroying the record prematurely.
     nsCOMPtr<nsIDNSRecord> rec;
     if (NS_SUCCEEDED(status)) {
         NS_ASSERTION(hostRecord, "no host record");
         rec = new nsDNSRecord(hostRecord);
         if (!rec)
             status = NS_ERROR_OUT_OF_MEMORY;
     }
     MOZ_EVENT_TRACER_DONE(this, "net::dns::lookup");
     mListener->OnLookupComplete(this, rec, status);
     mListener = nullptr;
     // release the reference to ourselves that was added before we were
     // handed off to the host resolver.
     NS_RELEASE_THIS();
 }
 bool
 nsDNSAsyncRequest::EqualsAsyncListener(nsIDNSListener *aListener)
 {
     return (aListener == mListener);
 }
 size_t
 nsDNSAsyncRequest::SizeOfIncludingThis(MallocSizeOf mallocSizeOf) const
 {
     size_t n = mallocSizeOf(this);
     // The following fields aren't measured.
     // - mHost, because it's a non-owning pointer
     // - mResolver, because it's a non-owning pointer
     // - mListener, because it's a non-owning pointer
     return n;
 }
 NS_IMPL_ISUPPORTS(nsDNSAsyncRequest, nsICancelable)
 NS_IMETHODIMP
 nsDNSAsyncRequest::Cancel(nsresult reason)
 {
     NS_ENSURE_ARG(NS_FAILED(reason));
     mResolver->DetachCallback(mHost.get(), mFlags, mAF, this, reason);
     return NS_OK;
 }
 //-----------------------------------------------------------------------------
 class nsDNSSyncRequest : public nsResolveHostCallback
 {
 public:
     nsDNSSyncRequest(PRMonitor *mon)
         : mDone(false)
         , mStatus(NS_OK)
         , mMonitor(mon) {}
     virtual ~nsDNSSyncRequest() {}
     void OnLookupComplete(nsHostResolver *, nsHostRecord *, nsresult);
     bool EqualsAsyncListener(nsIDNSListener *aListener);
     size_t SizeOfIncludingThis(mozilla::MallocSizeOf) const;
     bool                   mDone;
     nsresult               mStatus;
     nsRefPtr<nsHostRecord> mHostRecord;
 private:
     PRMonitor             *mMonitor;
 };
 void
 nsDNSSyncRequest::OnLookupComplete(nsHostResolver *resolver,
                                    nsHostRecord   *hostRecord,
                                    nsresult        status)
 {
     // store results, and wake up nsDNSService::Resolve to process results.
     PR_EnterMonitor(mMonitor);
     mDone = true;
     mStatus = status;
     mHostRecord = hostRecord;
     PR_Notify(mMonitor);
     PR_ExitMonitor(mMonitor);
 }
 bool
 nsDNSSyncRequest::EqualsAsyncListener(nsIDNSListener *aListener)
 {
     // Sync request: no listener to compare
     return false;
 }
 size_t
 nsDNSSyncRequest::SizeOfIncludingThis(MallocSizeOf mallocSizeOf) const
 {
     size_t n = mallocSizeOf(this);
     // The following fields aren't measured.
     // - mHostRecord, because it's a non-owning pointer
     // Measurement of the following members may be added later if DMD finds it
     // is worthwhile:
     // - mMonitor
     return n;
 }
 class NotifyDNSResolution: public nsRunnable
 {
 public:
     NotifyDNSResolution(nsMainThreadPtrHandle<nsIObserverService> &aObs,
                         const nsACString &aHostname)
         : mObs(aObs)
         , mHostname(aHostname)
     {
         MOZ_ASSERT(mObs);
     }
     NS_IMETHOD Run()
     {
         MOZ_ASSERT(NS_IsMainThread());
         mObs->NotifyObservers(nullptr,
                               "dns-resolution-request",
                               NS_ConvertUTF8toUTF16(mHostname).get());
         return NS_OK;
     }
 private:
     nsMainThreadPtrHandle<nsIObserverService> mObs;
     nsCString                                 mHostname;
 };
 //-----------------------------------------------------------------------------
 nsDNSService::nsDNSService()
     : mLock("nsDNSServer.mLock")
     , mFirstTime(true)
     , mOffline(false)
 {
 }
 nsDNSService::~nsDNSService()
 {
 }
 NS_IMPL_ISUPPORTS(nsDNSService, nsIDNSService, nsPIDNSService, nsIObserver,
                   nsIMemoryReporter)
 /******************************************************************************
  * nsDNSService impl:
  * singleton instance ctor/dtor methods
  ******************************************************************************/
 static nsDNSService *gDNSService;
 nsIDNSService*
 nsDNSService::GetXPCOMSingleton()
 {
     if (IsNeckoChild()) {
         return ChildDNSService::GetSingleton();
     }
     return GetSingleton();
 }
 nsDNSService*
 nsDNSService::GetSingleton()
 {
     NS_ASSERTION(!IsNeckoChild(), "not a parent process");
     if (gDNSService) {
         NS_ADDREF(gDNSService);
         return gDNSService;
     }
     gDNSService = new nsDNSService();
     if (gDNSService) {
         NS_ADDREF(gDNSService);
         if (NS_FAILED(gDNSService->Init())) {
               NS_RELEASE(gDNSService);
         }
     }
     return gDNSService;
 }
 NS_IMETHODIMP
 nsDNSService::Init()
 {
     if (mResolver)
         return NS_OK;
     NS_ENSURE_TRUE(!mResolver, NS_ERROR_ALREADY_INITIALIZED);
     // prefs
     uint32_t maxCacheEntries  = 400;
     uint32_t maxCacheLifetime = 120; // seconds
     uint32_t lifetimeGracePeriod = 60; // seconds
     bool     disableIPv6      = false;
     bool     disablePrefetch  = false;
     bool     disableDNS       = false;
     int      proxyType        = nsIProtocolProxyService::PROXYCONFIG_DIRECT;
     bool     notifyResolution = false;
     nsAdoptingCString ipv4OnlyDomains;
     nsAdoptingCString localDomains;
     // read prefs
     nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
     if (prefs) {
         int32_t val;
         if (NS_SUCCEEDED(prefs->GetIntPref(kPrefDnsCacheEntries, &val)))
             maxCacheEntries = (uint32_t) val;
         if (NS_SUCCEEDED(prefs->GetIntPref(kPrefDnsCacheExpiration, &val)))
             maxCacheLifetime = val;
         if (NS_SUCCEEDED(prefs->GetIntPref(kPrefDnsCacheGrace, &val)))
             lifetimeGracePeriod = val;
         // ASSUMPTION: pref branch does not modify out params on failure
         prefs->GetBoolPref(kPrefDisableIPv6, &disableIPv6);
         prefs->GetCharPref(kPrefIPv4OnlyDomains, getter_Copies(ipv4OnlyDomains));
         prefs->GetCharPref(kPrefDnsLocalDomains, getter_Copies(localDomains));
         prefs->GetBoolPref(kPrefDisablePrefetch, &disablePrefetch);
         // If a manual proxy is in use, disable prefetch implicitly
         prefs->GetIntPref("network.proxy.type", &proxyType);
         // If the user wants remote DNS, we should fail any lookups that still
         // make it here.
         prefs->GetBoolPref("network.proxy.socks_remote_dns", &disableDNS);
         prefs->GetBoolPref(kPrefDnsNotifyResolution, &notifyResolution);
     }
     if (mFirstTime) {
         mFirstTime = false;
         // register as prefs observer
         if (prefs) {
             prefs->AddObserver(kPrefDnsCacheEntries, this, false);
             prefs->AddObserver(kPrefDnsCacheExpiration, this, false);
             prefs->AddObserver(kPrefDnsCacheGrace, this, false);
             prefs->AddObserver(kPrefIPv4OnlyDomains, this, false);
             prefs->AddObserver(kPrefDnsLocalDomains, this, false);
             prefs->AddObserver(kPrefDisableIPv6, this, false);
             prefs->AddObserver(kPrefDisablePrefetch, this, false);
             prefs->AddObserver(kPrefDnsNotifyResolution, this, false);
             // Monitor these to see if there is a change in proxy configuration
             // If a manual proxy is in use, disable prefetch implicitly
             prefs->AddObserver("network.proxy.", this, false);
         }
         nsresult rv;
         nsCOMPtr<nsIObserverService> observerService =
             do_GetService("@mozilla.org/observer-service;1", &rv);
         if (NS_SUCCEEDED(rv)) {
             observerService->AddObserver(this, "last-pb-context-exited", false);
         }
     }
     nsDNSPrefetch::Initialize(this);
     // Don't initialize the resolver if we're in offline mode.
     // Later on, the IO service will reinitialize us when going online.
     if (gIOService->IsOffline() && !gIOService->IsComingOnline())
         return NS_OK;
     nsCOMPtr<nsIIDNService> idn = do_GetService(NS_IDNSERVICE_CONTRACTID);
     nsCOMPtr<nsIObserverService> obs =
         do_GetService(NS_OBSERVERSERVICE_CONTRACTID);
     nsRefPtr<nsHostResolver> res;
     nsresult rv = nsHostResolver::Create(maxCacheEntries,
                                          maxCacheLifetime,
                                          lifetimeGracePeriod,
                                          getter_AddRefs(res));
     if (NS_SUCCEEDED(rv)) {
         // now, set all of our member variables while holding the lock
         MutexAutoLock lock(mLock);
         mResolver = res;
         mIDN = idn;
         mIPv4OnlyDomains = ipv4OnlyDomains; // exchanges buffer ownership
         mDisableIPv6 = disableIPv6;
         mDisableDNS = disableDNS;
         // Disable prefetching either by explicit preference or if a manual proxy is configured
         mDisablePrefetch = disablePrefetch || (proxyType == nsIProtocolProxyService::PROXYCONFIG_MANUAL);
         mLocalDomains.Clear();
         if (localDomains) {
             nsAdoptingString domains;
             domains.AssignASCII(nsDependentCString(localDomains).get());
             nsCharSeparatedTokenizer tokenizer(domains, ',',
                                                nsCharSeparatedTokenizerTemplate<>::SEPARATOR_OPTIONAL);
             while (tokenizer.hasMoreTokens()) {
                 const nsSubstring& domain = tokenizer.nextToken();
                 mLocalDomains.PutEntry(nsDependentCString(NS_ConvertUTF16toUTF8(domain).get()));
             }
         }
         mNotifyResolution = notifyResolution;
         if (mNotifyResolution) {
             mObserverService =
               new nsMainThreadPtrHolder<nsIObserverService>(obs);
         }
     }
     RegisterWeakMemoryReporter(this);
     return rv;
 }
 NS_IMETHODIMP
 nsDNSService::Shutdown()
 {
     UnregisterWeakMemoryReporter(this);
     nsRefPtr<nsHostResolver> res;
     {
         MutexAutoLock lock(mLock);
         res = mResolver;
         mResolver = nullptr;
     }
     if (res)
         res->Shutdown();
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSService::GetOffline(bool *offline)
 {
     *offline = mOffline;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSService::SetOffline(bool offline)
 {
     mOffline = offline;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSService::GetPrefetchEnabled(bool *outVal)
 {
     *outVal = !mDisablePrefetch;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSService::SetPrefetchEnabled(bool inVal)
 {
     mDisablePrefetch = !inVal;
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSService::AsyncResolve(const nsACString  &hostname,
                            uint32_t           flags,
                            nsIDNSListener    *listener,
                            nsIEventTarget    *target_,
                            nsICancelable    **result)
 {
     // grab reference to global host resolver and IDN service.  beware
     // simultaneous shutdown!!
     nsRefPtr<nsHostResolver> res;
     nsCOMPtr<nsIIDNService> idn;
     nsCOMPtr<nsIEventTarget> target = target_;
     bool localDomain = false;
     {
         MutexAutoLock lock(mLock);
         if (mDisablePrefetch && (flags & RESOLVE_SPECULATE))
             return NS_ERROR_DNS_LOOKUP_QUEUE_FULL;
         res = mResolver;
         idn = mIDN;
         localDomain = mLocalDomains.GetEntry(hostname);
     }
     if (mNotifyResolution) {
         NS_DispatchToMainThread(new NotifyDNSResolution(mObserverService,
                                                         hostname));
     }
     PRNetAddr tempAddr;
     if (mDisableDNS) {
         // Allow IP lookups through, but nothing else.
         if (PR_StringToNetAddr(hostname.BeginReading(), &tempAddr) != PR_SUCCESS) {
             return NS_ERROR_UNKNOWN_PROXY_HOST; // XXX: NS_ERROR_NOT_IMPLEMENTED?
         }
     }
     if (!res)
         return NS_ERROR_OFFLINE;
     if (mOffline)
         flags |= RESOLVE_OFFLINE;
     const nsACString *hostPtr = &hostname;
     if (localDomain) {
         hostPtr = &(NS_LITERAL_CSTRING("localhost"));
     }
     nsresult rv;
     nsAutoCString hostACE;
     if (idn && !IsASCII(*hostPtr)) {
         if (IsUTF8(*hostPtr) &&
             NS_SUCCEEDED(idn->ConvertUTF8toACE(*hostPtr, hostACE))) {
             hostPtr = &hostACE;
         } else {
             return NS_ERROR_FAILURE;
         }
     }
     // make sure JS callers get notification on the main thread
     nsCOMPtr<nsIXPConnectWrappedJS> wrappedListener = do_QueryInterface(listener);
     if (wrappedListener && !target) {
         nsCOMPtr<nsIThread> mainThread;
         NS_GetMainThread(getter_AddRefs(mainThread));
         target = do_QueryInterface(mainThread);
     }
     if (target) {
       listener = new DNSListenerProxy(listener, target);
     }
     uint16_t af = GetAFForLookup(*hostPtr, flags);
     nsDNSAsyncRequest *req =
             new nsDNSAsyncRequest(res, *hostPtr, listener, flags, af);
     if (!req)
         return NS_ERROR_OUT_OF_MEMORY;
     NS_ADDREF(*result = req);
     MOZ_EVENT_TRACER_NAME_OBJECT(req, hostname.BeginReading());
     MOZ_EVENT_TRACER_WAIT(req, "net::dns::lookup");
     // addref for resolver; will be released when OnLookupComplete is called.
     NS_ADDREF(req);
     rv = res->ResolveHost(req->mHost.get(), flags, af, req);
     if (NS_FAILED(rv)) {
         NS_RELEASE(req);
         NS_RELEASE(*result);
     }
     return rv;
 }
 NS_IMETHODIMP
 nsDNSService::CancelAsyncResolve(const nsACString  &aHostname,
                                  uint32_t           aFlags,
                                  nsIDNSListener    *aListener,
                                  nsresult           aReason)
 {
     // grab reference to global host resolver and IDN service.  beware
     // simultaneous shutdown!!
     nsRefPtr<nsHostResolver> res;
     nsCOMPtr<nsIIDNService> idn;
     {
         MutexAutoLock lock(mLock);
         if (mDisablePrefetch && (aFlags & RESOLVE_SPECULATE))
             return NS_ERROR_DNS_LOOKUP_QUEUE_FULL;
         res = mResolver;
         idn = mIDN;
     }
     if (!res)
         return NS_ERROR_OFFLINE;
     nsCString hostname(aHostname);
     nsAutoCString hostACE;
     if (idn && !IsASCII(aHostname)) {
         if (IsUTF8(aHostname) &&
             NS_SUCCEEDED(idn->ConvertUTF8toACE(aHostname, hostACE))) {
             hostname = hostACE;
         } else {
             return NS_ERROR_FAILURE;
         }
     }
     uint16_t af = GetAFForLookup(hostname, aFlags);
     res->CancelAsyncRequest(hostname.get(), aFlags, af, aListener, aReason);
     return NS_OK;
 }
 NS_IMETHODIMP
 nsDNSService::Resolve(const nsACString &hostname,
                       uint32_t          flags,
                       nsIDNSRecord    **result)
 {
     // grab reference to global host resolver and IDN service.  beware
     // simultaneous shutdown!!
     nsRefPtr<nsHostResolver> res;
     nsCOMPtr<nsIIDNService> idn;
     bool localDomain = false;
     {
         MutexAutoLock lock(mLock);
         res = mResolver;
         idn = mIDN;
         localDomain = mLocalDomains.GetEntry(hostname);
     }
     if (mNotifyResolution) {
         NS_DispatchToMainThread(new NotifyDNSResolution(mObserverService,
                                                         hostname));
     }
     NS_ENSURE_TRUE(res, NS_ERROR_OFFLINE);
     if (mOffline)
         flags |= RESOLVE_OFFLINE;
     PRNetAddr tempAddr;
     if (mDisableDNS) {
         // Allow IP lookups through, but nothing else.
         if (PR_StringToNetAddr(hostname.BeginReading(), &tempAddr) != PR_SUCCESS) {
             return NS_ERROR_UNKNOWN_PROXY_HOST; // XXX: NS_ERROR_NOT_IMPLEMENTED?
         }
     }
     const nsACString *hostPtr = &hostname;
     if (localDomain) {
         hostPtr = &(NS_LITERAL_CSTRING("localhost"));
     }
     nsresult rv;
     nsAutoCString hostACE;
     if (idn && !IsASCII(*hostPtr)) {
         if (IsUTF8(*hostPtr) &&
             NS_SUCCEEDED(idn->ConvertUTF8toACE(*hostPtr, hostACE))) {
             hostPtr = &hostACE;
         } else {
             return NS_ERROR_FAILURE;
         }
     }
     //
     // sync resolve: since the host resolver only works asynchronously, we need
     // to use a mutex and a condvar to wait for the result.  however, since the
     // result may be in the resolvers cache, we might get called back recursively
     // on the same thread.  so, our mutex needs to be re-entrant.  in other words,
     // we need to use a monitor! ;-)
     //
     PRMonitor *mon = PR_NewMonitor();
     if (!mon)
         return NS_ERROR_OUT_OF_MEMORY;
     PR_EnterMonitor(mon);
     nsDNSSyncRequest syncReq(mon);
     uint16_t af = GetAFForLookup(*hostPtr, flags);
     rv = res->ResolveHost(PromiseFlatCString(*hostPtr).get(), flags, af, &syncReq);
     if (NS_SUCCEEDED(rv)) {
         // wait for result
         while (!syncReq.mDone)
             PR_Wait(mon, PR_INTERVAL_NO_TIMEOUT);
         if (NS_FAILED(syncReq.mStatus))
             rv = syncReq.mStatus;
         else {
             NS_ASSERTION(syncReq.mHostRecord, "no host record");
             nsDNSRecord *rec = new nsDNSRecord(syncReq.mHostRecord);
             if (!rec)
                 rv = NS_ERROR_OUT_OF_MEMORY;
             else
                 NS_ADDREF(*result = rec);
         }
     }
     PR_ExitMonitor(mon);
     PR_DestroyMonitor(mon);
     return rv;
 }
 NS_IMETHODIMP
 nsDNSService::GetMyHostName(nsACString &result)
 {
     char name[100];
     if (PR_GetSystemInfo(PR_SI_HOSTNAME, name, sizeof(name)) == PR_SUCCESS) {
         result = name;
         return NS_OK;
     }
     return NS_ERROR_FAILURE;
 }
 NS_IMETHODIMP
 nsDNSService::Observe(nsISupports *subject, const char *topic, const char16_t *data)
 {
     // we are only getting called if a preference has changed.
     NS_ASSERTION(strcmp(topic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID) == 0 ||
         strcmp(topic, "last-pb-context-exited") == 0,
         "unexpected observe call");
     //
     // Shutdown and this function are both only called on the UI thread, so we don't
     // have to worry about mResolver being cleared out from under us.
     //
     // NOTE Shutting down and reinitializing the service like this is obviously
     // suboptimal if Observe gets called several times in a row, but we don't
     // expect that to be the case.
     //
     if (mResolver) {
         Shutdown();
     }
     Init();
     return NS_OK;
 }
 uint16_t
 nsDNSService::GetAFForLookup(const nsACString &host, uint32_t flags)
 {
     if (mDisableIPv6 || (flags & RESOLVE_DISABLE_IPV6))
         return PR_AF_INET;
     MutexAutoLock lock(mLock);
     uint16_t af = PR_AF_UNSPEC;
     if (!mIPv4OnlyDomains.IsEmpty()) {
         const char *domain, *domainEnd, *end;
         uint32_t hostLen, domainLen;
         // see if host is in one of the IPv4-only domains
         domain = mIPv4OnlyDomains.BeginReading();
         domainEnd = mIPv4OnlyDomains.EndReading();
         nsACString::const_iterator hostStart;
         host.BeginReading(hostStart);
         hostLen = host.Length();
         do {
             // skip any whitespace
             while (*domain == ' ' || *domain == '\t')
                 ++domain;
             // find end of this domain in the string
             end = strchr(domain, ',');
             if (!end)
                 end = domainEnd;
             // to see if the hostname is in the domain, check if the domain
             // matches the end of the hostname.
             domainLen = end - domain;
             if (domainLen && hostLen >= domainLen) {
                 const char *hostTail = hostStart.get() + hostLen - domainLen;
                 if (PL_strncasecmp(domain, hostTail, domainLen) == 0) {
                     // now, make sure either that the hostname is a direct match or
                     // that the hostname begins with a dot.
                     if (hostLen == domainLen ||
                             *hostTail == '.' || *(hostTail - 1) == '.') {
                         af = PR_AF_INET;
                         break;
                     }
                 }
             }
             domain = end + 1;
         } while (*end);
     }
     if ((af != PR_AF_INET) && (flags & RESOLVE_DISABLE_IPV4))
         af = PR_AF_INET6;
     return af;
 }
 NS_IMETHODIMP
 nsDNSService::GetDNSCacheEntries(nsTArray<mozilla::net::DNSCacheEntries> *args)
 {
     NS_ENSURE_TRUE(mResolver, NS_ERROR_NOT_INITIALIZED);
     mResolver->GetDNSCacheEntries(args);
     return NS_OK;
 }
 static size_t
 SizeOfLocalDomainsEntryExcludingThis(nsCStringHashKey* entry,
                                      MallocSizeOf mallocSizeOf, void*)
 {
     return entry->GetKey().SizeOfExcludingThisMustBeUnshared(mallocSizeOf);
 }
 size_t
 nsDNSService::SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const
 {
     // Measurement of the following members may be added later if DMD finds it
     // is worthwhile:
     // - mIDN
     // - mLock
     size_t n = mallocSizeOf(this);
     n += mResolver->SizeOfIncludingThis(mallocSizeOf);
     n += mIPv4OnlyDomains.SizeOfExcludingThisMustBeUnshared(mallocSizeOf);
     n += mLocalDomains.SizeOfExcludingThis(SizeOfLocalDomainsEntryExcludingThis,
                                            mallocSizeOf);
     return n;
 }
 MOZ_DEFINE_MALLOC_SIZE_OF(DNSServiceMallocSizeOf)
 NS_IMETHODIMP
 nsDNSService::CollectReports(nsIHandleReportCallback* aHandleReport,
                              nsISupports* aData)
 {
     return MOZ_COLLECT_REPORT(
         "explicit/network/dns-service", KIND_HEAP, UNITS_BYTES,
         SizeOfIncludingThis(DNSServiceMallocSizeOf),
         "Memory used for the DNS service.");
 }

The Tor Browser / annotate

netwerk/dns/nsDNSService2.cpp@ca08bd8f51b2 (annotated)

netwerk/dns/nsDNSService2.cpp