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gecko-dev/netwerk/dns/nsHostResolver.h

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/* vim:set ts=4 sw=4 sts=4 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/. */
#ifndef nsHostResolver_h__
#define nsHostResolver_h__
#include "nscore.h"
#include "prnetdb.h"
#include "PLDHashTable.h"
#include "mozilla/CondVar.h"
#include "mozilla/Mutex.h"
#include "nsISupportsImpl.h"
#include "nsIDNSListener.h"
#include "nsIDNSService.h"
#include "nsTArray.h"
#include "GetAddrInfo.h"
#include "mozilla/net/DNS.h"
#include "mozilla/net/DashboardTypes.h"
#include "mozilla/Atomics.h"
#include "mozilla/LinkedList.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/UniquePtr.h"
#include "nsRefPtrHashtable.h"
#include "nsIThreadPool.h"
class nsHostResolver;
class nsResolveHostCallback;
namespace mozilla { namespace net {
class TRR;
enum ResolverMode {
MODE_NATIVEONLY, // 0 - TRR OFF (by default)
MODE_PARALLEL, // 1 - race and use the first response
MODE_TRRFIRST, // 2 - fallback to native on TRR failure
MODE_TRRONLY, // 3 - don't even fallback
MODE_SHADOW, // 4 - race for stats, but always use native result
MODE_TRROFF // 5 - identical to MODE_NATIVEONLY but explicitly selected
};
} }
#define TRR_DISABLED(x) (((x) == MODE_NATIVEONLY) || ((x) == MODE_TRROFF))
extern mozilla::Atomic<bool, mozilla::Relaxed> gNativeIsLocalhost;
#define MAX_RESOLVER_THREADS_FOR_ANY_PRIORITY 3
#define MAX_RESOLVER_THREADS_FOR_HIGH_PRIORITY 5
#define MAX_NON_PRIORITY_REQUESTS 150
#define MAX_RESOLVER_THREADS (MAX_RESOLVER_THREADS_FOR_ANY_PRIORITY + \
MAX_RESOLVER_THREADS_FOR_HIGH_PRIORITY)
struct nsHostKey
{
const nsCString host;
uint16_t type;
uint16_t flags;
uint16_t af;
bool pb;
const nsCString originSuffix;
explicit nsHostKey(const nsACString& host, uint16_t type, uint16_t flags,
uint16_t af, bool pb, const nsACString& originSuffix);
bool operator==(const nsHostKey& other) const;
size_t SizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
PLDHashNumber Hash() const;
};
/**
* nsHostRecord - ref counted object type stored in host resolver cache.
*/
class nsHostRecord :
public mozilla::LinkedListElement<RefPtr<nsHostRecord>>,
public nsHostKey
{
typedef mozilla::Mutex Mutex;
public:
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(nsHostRecord)
/* a fully resolved host record has either a non-null |addr_info| or |addr|
* field. if |addr_info| is null, it implies that the |host| is an IP
* address literal. in which case, |addr| contains the parsed address.
* otherwise, if |addr_info| is non-null, then it contains one or many
* IP addresses corresponding to the given host name. if both |addr_info|
* and |addr| are null, then the given host has not yet been fully resolved.
* |af| is the address family of the record we are querying for.
*/
/* the lock protects |addr_info| and |addr_info_gencnt| because they
* are mutable and accessed by the resolver worker thread and the
* nsDNSService2 class. |addr| doesn't change after it has been
* assigned a value. only the resolver worker thread modifies
* nsHostRecord (and only in nsHostResolver::CompleteLookup);
* the other threads just read it. therefore the resolver worker
* thread doesn't need to lock when reading |addr_info|.
*/
Mutex addr_info_lock;
int addr_info_gencnt; /* generation count of |addr_info| */
mozilla::net::AddrInfo *addr_info;
mozilla::UniquePtr<mozilla::net::NetAddr> addr;
bool negative; /* True if this record is a cache of a failed lookup.
Negative cache entries are valid just like any other
(though never for more than 60 seconds), but a use
of that negative entry forces an asynchronous refresh. */
enum ExpirationStatus {
EXP_VALID,
EXP_GRACE,
EXP_EXPIRED,
};
ExpirationStatus CheckExpiration(const mozilla::TimeStamp& now) const;
// When the record began being valid. Used mainly for bookkeeping.
mozilla::TimeStamp mValidStart;
// When the record is no longer valid (it's time of expiration)
mozilla::TimeStamp mValidEnd;
// When the record enters its grace period. This must be before mValidEnd.
// If a record is in its grace period (and not expired), it will be used
// but a request to refresh it will be made.
mozilla::TimeStamp mGraceStart;
// When the lookups of this record started and their durations
mozilla::TimeStamp mTrrStart;
mozilla::TimeStamp mNativeStart;
mozilla::TimeDuration mTrrDuration;
mozilla::TimeDuration mNativeDuration;
// Convenience function for setting the timestamps above (mValidStart,
// mValidEnd, and mGraceStart). valid and grace are durations in seconds.
void SetExpiration(const mozilla::TimeStamp& now, unsigned int valid,
unsigned int grace);
void CopyExpirationTimesAndFlagsFrom(const nsHostRecord *aFromHostRecord);
// Checks if the record is usable (not expired and has a value)
bool HasUsableResult(const mozilla::TimeStamp& now, uint16_t queryFlags = 0) const;
// Mark hostrecord as not usable
void Invalidate();
// hold addr_info_lock when calling the blacklist functions
bool Blacklisted(mozilla::net::NetAddr *query);
void ResetBlacklist();
void ReportUnusable(mozilla::net::NetAddr *addr);
size_t SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
enum DnsPriority {
DNS_PRIORITY_LOW,
DNS_PRIORITY_MEDIUM,
DNS_PRIORITY_HIGH,
};
static DnsPriority GetPriority(uint16_t aFlags);
bool RemoveOrRefresh(); // Mark records currently being resolved as needed
// to resolve again.
bool IsTRR() { return mTRRUsed; }
void ResolveComplete();
void Cancel();
mozilla::net::ResolverMode mResolverMode;
nsTArray<nsCString> mRequestByTypeResult;
Mutex mRequestByTypeResultLock;
private:
friend class nsHostResolver;
explicit nsHostRecord(const nsHostKey& key);
mozilla::LinkedList<RefPtr<nsResolveHostCallback>> mCallbacks;
nsAutoPtr<mozilla::net::AddrInfo> mFirstTRR; // partial TRR storage
nsresult mFirstTRRresult;
uint16_t mResolving; // counter of outstanding resolving calls
uint8_t mTRRSuccess; // number of successful TRR responses
uint8_t mNativeSuccess; // number of native lookup responses
uint16_t mNative : 1; // true if this record is being resolved "natively",
// which means that it is either on the pending queue
// or owned by one of the worker threads. */
uint16_t mTRRUsed : 1; // TRR was used on this record
uint16_t mNativeUsed : 1;
uint16_t onQueue : 1; // true if pending and on the queue (not yet given to getaddrinfo())
uint16_t usingAnyThread : 1; // true if off queue and contributing to mActiveAnyThreadCount
uint16_t mDoomed : 1; // explicitly expired
uint16_t mDidCallbacks : 1;
uint16_t mGetTtl : 1;
// when the results from this resolve is returned, it is not to be
// trusted, but instead a new resolve must be made!
uint16_t mResolveAgain : 1;
enum {
INIT, STARTED, OK, FAILED
} mTrrAUsed, mTrrAAAAUsed;
Mutex mTrrLock; // lock when accessing the mTrrA[AAA] pointers
RefPtr<mozilla::net::TRR> mTrrA;
RefPtr<mozilla::net::TRR> mTrrAAAA;
RefPtr<mozilla::net::TRR> mTrrTxt;
// The number of times ReportUnusable() has been called in the record's
// lifetime.
uint32_t mBlacklistedCount;
// a list of addresses associated with this record that have been reported
// as unusable. the list is kept as a set of strings to make it independent
// of gencnt.
nsTArray<nsCString> mBlacklistedItems;
~nsHostRecord();
};
/**
* This class is used to notify listeners when a ResolveHost operation is
* complete. Classes that derive it must implement threadsafe nsISupports
* to be able to use RefPtr with this class.
*/
class nsResolveHostCallback
: public mozilla::LinkedListElement<RefPtr<nsResolveHostCallback>>
, public nsISupports
{
public:
/**
* OnResolveHostComplete
*
* this function is called to complete a host lookup initiated by
* nsHostResolver::ResolveHost. it may be invoked recursively from
* ResolveHost or on an unspecified background thread.
*
* NOTE: it is the responsibility of the implementor of this method
* to handle the callback in a thread safe manner.
*
* @param resolver
* nsHostResolver object associated with this result
* @param record
* the host record containing the results of the lookup
* @param status
* if successful, |record| contains non-null results
*/
virtual void OnResolveHostComplete(nsHostResolver *resolver,
nsHostRecord *record,
nsresult status) = 0;
/**
* EqualsAsyncListener
*
* Determines if the listener argument matches the listener member var.
* For subclasses not implementing a member listener, should return false.
* For subclasses having a member listener, the function should check if
* they are the same. Used for cases where a pointer to an object
* implementing nsResolveHostCallback is unknown, but a pointer to
* the original listener is known.
*
* @param aListener
* nsIDNSListener object associated with the original request
*/
virtual bool EqualsAsyncListener(nsIDNSListener *aListener) = 0;
virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf) const = 0;
protected:
virtual ~nsResolveHostCallback() = default;
};
class AHostResolver
{
public:
AHostResolver() = default;
virtual ~AHostResolver() = default;
NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
enum LookupStatus {
LOOKUP_OK,
LOOKUP_RESOLVEAGAIN,
};
virtual LookupStatus CompleteLookup(nsHostRecord *, nsresult, mozilla::net::AddrInfo *, bool pb) = 0;
virtual LookupStatus CompleteLookupByType(nsHostRecord *, nsresult,
const nsTArray<nsCString> *aResult,
uint32_t aTtl, bool pb) = 0;
virtual nsresult GetHostRecord(const nsACString &host,
uint16_t flags, uint16_t af, bool pb,
const nsCString &originSuffix,
nsHostRecord **result)
{
return NS_ERROR_FAILURE;
}
virtual nsresult TrrLookup_unlocked(nsHostRecord *, mozilla::net::TRR *pushedTRR = nullptr)
{
return NS_ERROR_FAILURE;
}
};
/**
* nsHostResolver - an asynchronous host name resolver.
*/
class nsHostResolver : public nsISupports, public AHostResolver
{
typedef mozilla::CondVar CondVar;
typedef mozilla::Mutex Mutex;
public:
NS_DECL_THREADSAFE_ISUPPORTS
/**
* creates an addref'd instance of a nsHostResolver object.
*/
static nsresult Create(uint32_t maxCacheEntries, // zero disables cache
uint32_t defaultCacheEntryLifetime, // seconds
uint32_t defaultGracePeriod, // seconds
nsHostResolver **resolver);
/**
* Set (new) cache limits.
*/
void SetCacheLimits(uint32_t maxCacheEntries, // zero disables cache
uint32_t defaultCacheEntryLifetime, // seconds
uint32_t defaultGracePeriod); // seconds
/**
* puts the resolver in the shutdown state, which will cause any pending
* callbacks to be detached. any future calls to ResolveHost will fail.
*/
void Shutdown();
/**
* resolve the given hostname and originAttributes asynchronously. the caller
* can synthesize a synchronous host lookup using a lock and a cvar. as noted
* above the callback will occur re-entrantly from an unspecified thread. the
* host lookup cannot be canceled (cancelation can be layered above this by
* having the callback implementation return without doing anything).
*/
nsresult ResolveHost(const nsACString &hostname,
uint16_t type,
const mozilla::OriginAttributes &aOriginAttributes,
uint16_t flags,
uint16_t af,
nsResolveHostCallback *callback);
/**
* removes the specified callback from the nsHostRecord for the given
* hostname, originAttributes, flags, and address family. these parameters
* should correspond to the parameters passed to ResolveHost. this function
* executes the callback if the callback is still pending with the given status.
*/
void DetachCallback(const nsACString &hostname,
uint16_t type,
const mozilla::OriginAttributes &aOriginAttributes,
uint16_t flags,
uint16_t af,
nsResolveHostCallback *callback,
nsresult status);
/**
* Cancels an async request associated with the hostname, originAttributes, flags,
* address family and listener. Cancels first callback found which matches
* these criteria. These parameters should correspond to the parameters
* passed to ResolveHost. If this is the last callback associated with the
* host record, it is removed from any request queues it might be on.
*/
void CancelAsyncRequest(const nsACString &host,
uint16_t type,
const mozilla::OriginAttributes &aOriginAttributes,
uint16_t flags,
uint16_t af,
nsIDNSListener *aListener,
nsresult status);
/**
* values for the flags parameter passed to ResolveHost and DetachCallback
* that may be bitwise OR'd together.
*
* NOTE: in this implementation, these flags correspond exactly in value
* to the flags defined on nsIDNSService.
*/
enum {
RES_BYPASS_CACHE = nsIDNSService::RESOLVE_BYPASS_CACHE,
RES_CANON_NAME = nsIDNSService::RESOLVE_CANONICAL_NAME,
RES_PRIORITY_MEDIUM = nsIDNSService::RESOLVE_PRIORITY_MEDIUM,
RES_PRIORITY_LOW = nsIDNSService::RESOLVE_PRIORITY_LOW,
RES_SPECULATE = nsIDNSService::RESOLVE_SPECULATE,
//RES_DISABLE_IPV6 = nsIDNSService::RESOLVE_DISABLE_IPV6, // Not used
RES_OFFLINE = nsIDNSService::RESOLVE_OFFLINE,
//RES_DISABLE_IPv4 = nsIDNSService::RESOLVE_DISABLE_IPV4, // Not Used
RES_ALLOW_NAME_COLLISION = nsIDNSService::RESOLVE_ALLOW_NAME_COLLISION,
RES_DISABLE_TRR = nsIDNSService::RESOLVE_DISABLE_TRR,
RES_REFRESH_CACHE = nsIDNSService::RESOLVE_REFRESH_CACHE
};
size_t SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
/**
* Flush the DNS cache.
*/
void FlushCache();
LookupStatus CompleteLookup(nsHostRecord *, nsresult, mozilla::net::AddrInfo *, bool pb) override;
LookupStatus CompleteLookupByType(nsHostRecord *, nsresult,
const nsTArray<nsCString> *aResult,
uint32_t aTtl, bool pb) override;
nsresult GetHostRecord(const nsACString &host,
uint16_t flags, uint16_t af, bool pb,
const nsCString &originSuffix,
nsHostRecord **result) override;
nsresult TrrLookup_unlocked(nsHostRecord *, mozilla::net::TRR *pushedTRR = nullptr) override;
private:
explicit nsHostResolver(uint32_t maxCacheEntries,
uint32_t defaultCacheEntryLifetime,
uint32_t defaultGracePeriod);
virtual ~nsHostResolver();
nsresult Init();
// In debug builds it asserts that the element is in the list.
void AssertOnQ(nsHostRecord *, mozilla::LinkedList<RefPtr<nsHostRecord>>&);
mozilla::net::ResolverMode Mode();
nsresult NativeLookup(nsHostRecord *);
nsresult TrrLookup(nsHostRecord *, mozilla::net::TRR *pushedTRR = nullptr);
// Kick-off a name resolve operation, using native resolver and/or TRR
nsresult NameLookup(nsHostRecord *);
bool GetHostToLookup(nsHostRecord **m);
// Removes the first element from the list and returns it AddRef-ed in aResult
// Should not be called for an empty linked list.
void DeQueue(mozilla::LinkedList<RefPtr<nsHostRecord>>& aQ, nsHostRecord **aResult);
// Cancels host records in the pending queue and also
// calls CompleteLookup with the NS_ERROR_ABORT result code.
void ClearPendingQueue(mozilla::LinkedList<RefPtr<nsHostRecord>>& aPendingQ);
nsresult ConditionallyCreateThread(nsHostRecord *rec);
/**
* Starts a new lookup in the background for entries that are in the grace
* period with a failed connect or all cached entries are negative.
*/
nsresult ConditionallyRefreshRecord(nsHostRecord *rec, const nsACString &host);
void AddToEvictionQ(nsHostRecord* rec);
void ThreadFunc();
enum {
METHOD_HIT = 1,
METHOD_RENEWAL = 2,
METHOD_NEGATIVE_HIT = 3,
METHOD_LITERAL = 4,
METHOD_OVERFLOW = 5,
METHOD_NETWORK_FIRST = 6,
METHOD_NETWORK_SHARED = 7
};
uint32_t mMaxCacheEntries;
uint32_t mDefaultCacheLifetime; // granularity seconds
uint32_t mDefaultGracePeriod; // granularity seconds
mutable Mutex mLock; // mutable so SizeOfIncludingThis can be const
CondVar mIdleTaskCV;
nsRefPtrHashtable<nsGenericHashKey<nsHostKey>, nsHostRecord> mRecordDB;
mozilla::LinkedList<RefPtr<nsHostRecord>> mHighQ;
mozilla::LinkedList<RefPtr<nsHostRecord>> mMediumQ;
mozilla::LinkedList<RefPtr<nsHostRecord>> mLowQ;
mozilla::LinkedList<RefPtr<nsHostRecord>> mEvictionQ;
uint32_t mEvictionQSize;
PRTime mCreationTime;
mozilla::TimeDuration mLongIdleTimeout;
mozilla::TimeDuration mShortIdleTimeout;
RefPtr<nsIThreadPool> mResolverThreads;
mozilla::Atomic<bool> mShutdown;
mozilla::Atomic<uint32_t> mNumIdleTasks;
mozilla::Atomic<uint32_t> mActiveTaskCount;
mozilla::Atomic<uint32_t> mActiveAnyThreadCount;
mozilla::Atomic<uint32_t> mPendingCount;
// Set the expiration time stamps appropriately.
void PrepareRecordExpiration(nsHostRecord* rec) const;
public:
/*
* Called by the networking dashboard via the DnsService2
*/
void GetDNSCacheEntries(nsTArray<mozilla::net::DNSCacheEntries> *);
};
#endif // nsHostResolver_h__
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