Index: net/dns/dns_client.cc |
diff --git a/net/dns/dns_client.cc b/net/dns/dns_client.cc |
index de60cc33fee98c30b3c7844035b1bbb3443bacf0..501d5dc1fd3524b1ccc12f39c176456fe0b5a71b 100644 |
--- a/net/dns/dns_client.cc |
+++ b/net/dns/dns_client.cc |
@@ -2,89 +2,512 @@ |
// Use of this source code is governed by a BSD-style license that can be |
// found in the LICENSE file. |
-#include "net/dns/dns_client.h" |
+#include <deque> |
+#include <string> |
+#include <vector> |
#include "base/bind.h" |
+#include "base/memory/ref_counted.h" |
+#include "base/memory/scoped_ptr.h" |
+#include "base/memory/weak_ptr.h" |
+#include "base/message_loop.h" |
+#include "base/rand_util.h" |
+#include "base/stl_util.h" |
#include "base/string_piece.h" |
+#include "base/threading/non_thread_safe.h" |
+#include "base/timer.h" |
+#include "net/base/completion_callback.h" |
+#include "net/base/dns_util.h" |
+#include "net/base/io_buffer.h" |
+#include "net/base/ip_endpoint.h" |
#include "net/base/net_errors.h" |
+#include "net/base/net_log.h" |
+#include "net/dns/dns_client.h" |
mmenke
2012/01/13 16:44:37
This should go first, above the other includes, pe
|
+#include "net/dns/dns_protocol.h" |
+#include "net/dns/dns_query.h" |
#include "net/dns/dns_response.h" |
#include "net/dns/dns_session.h" |
-#include "net/dns/dns_transaction.h" |
#include "net/socket/client_socket_factory.h" |
+#include "net/udp/datagram_client_socket.h" |
namespace net { |
-DnsClient::Request::Request(const base::StringPiece& qname, |
- uint16 qtype, |
- const RequestCallback& callback) |
- : qname_(qname.data(), qname.size()), |
- qtype_(qtype), |
- callback_(callback) { |
+namespace { |
+ |
+// Count labels in the fully-qualified name in DNS format. |
+int CountLabels(const std::string& name) { |
+ size_t count = 0; |
+ for (size_t i = 0; i < name.size() && name[i]; i+= name[i] + 1) |
cbentzel
2012/01/13 13:39:54
Nit: space between i and +=
|
+ ++count; |
+ return count; |
} |
-DnsClient::Request::~Request() {} |
+class StartParameters : public NetLog::EventParameters { |
+ public: |
+ StartParameters(const std::string& hostname, |
+ uint16 qtype, |
+ const NetLog::Source& source) |
+ : hostname_(hostname), qtype_(qtype), source_(source) {} |
-// Implementation of DnsClient that uses DnsTransaction to serve requests. |
-class DnsClientImpl : public DnsClient { |
+ virtual Value* ToValue() const { |
mmenke
2012/01/13 16:44:37
nit: OVERRIDE
|
+ DictionaryValue* dict = new DictionaryValue(); |
+ dict->SetString("hostname", hostname_); |
+ dict->SetInteger("query_type", qtype_); |
+ dict->Set("source_dependency", source_.ToValue()); |
+ return dict; |
+ } |
+ |
+ private: |
+ std::string hostname_; |
+ uint16 qtype_; |
mmenke
2012/01/13 16:44:37
nit: Both of these can be const
|
+ const NetLog::Source source_; |
+}; |
+ |
+class ResponseParameters : public NetLog::EventParameters { |
+ public: |
+ ResponseParameters(int rcode, int answer_count, const NetLog::Source& source) |
+ : rcode_(rcode), answer_count_(answer_count), source_(source) {} |
+ |
+ virtual Value* ToValue() const { |
mmenke
2012/01/13 16:44:37
nit: OVERRIDE
|
+ DictionaryValue* dict = new DictionaryValue(); |
+ dict->SetInteger("rcode", rcode_); |
+ dict->SetInteger("answer_count", answer_count_); |
+ dict->Set("source_dependency", source_.ToValue()); |
+ return dict; |
+ } |
+ |
+ private: |
+ int rcode_; |
+ int answer_count_; |
mmenke
2012/01/13 16:44:37
nit: Both of these can be const
|
+ const NetLog::Source source_; |
+}; |
+ |
+// ---------------------------------------------------------------------------- |
+ |
+// A single asynchronous DNS exchange over UDP, which consists of sending out a |
+// DNS query, waiting for a response, and returning the response that it |
+// matches. Logging is done in the socket and in the outer DnsTransaction. |
+class DnsUDPAttempt { |
+ public: |
+ DnsUDPAttempt(scoped_ptr<DatagramClientSocket> socket, |
+ const IPEndPoint& server, |
+ scoped_ptr<DnsQuery> query, |
+ const CompletionCallback& callback) |
+ : next_state_(STATE_NONE), |
+ socket_(socket.Pass()), |
+ server_(server), |
+ query_(query.Pass()), |
+ callback_(callback) { |
+ } |
+ |
+ // Starts the attempt. Returns ERR_IO_PENDING if cannot complete synchronously |
+ // and calls |callback| upon completion. |
+ int Start() { |
+ DCHECK_EQ(STATE_NONE, next_state_); |
+ next_state_ = STATE_CONNECT; |
+ return DoLoop(OK); |
+ } |
+ |
+ const DnsQuery* query() { |
mmenke
2012/01/13 16:44:37
nit: const
|
+ return query_.get(); |
+ } |
+ |
+ const DatagramClientSocket* socket() const { |
+ return socket_.get(); |
+ } |
+ |
+ // Returns the response or NULL if has not received a matching response from |
+ // the server. |
+ const DnsResponse* response() const { |
+ return (response_.get() != NULL && response_->Parser().IsValid()) ? |
+ response_.get() : NULL; |
+ } |
+ |
+ private: |
+ enum State { |
+ STATE_CONNECT, |
+ STATE_SEND_QUERY, |
+ STATE_SEND_QUERY_COMPLETE, |
+ STATE_READ_RESPONSE, |
+ STATE_READ_RESPONSE_COMPLETE, |
+ STATE_NONE, |
+ }; |
+ |
+ int DoLoop(int result) { |
+ DCHECK_NE(STATE_NONE, next_state_); |
+ int rv = result; |
+ do { |
+ State state = next_state_; |
+ next_state_ = STATE_NONE; |
+ switch (state) { |
+ case STATE_CONNECT: |
+ rv = DoConnect(); |
+ break; |
+ case STATE_SEND_QUERY: |
+ rv = DoSendQuery(); |
+ break; |
+ case STATE_SEND_QUERY_COMPLETE: |
+ rv = DoSendQueryComplete(rv); |
+ break; |
+ case STATE_READ_RESPONSE: |
+ rv = DoReadResponse(); |
+ break; |
+ case STATE_READ_RESPONSE_COMPLETE: |
+ rv = DoReadResponseComplete(rv); |
+ break; |
+ default: |
+ NOTREACHED(); |
+ break; |
+ } |
+ } while (rv != ERR_IO_PENDING && next_state_ != STATE_NONE); |
+ |
+ return rv; |
+ } |
+ |
+ int DoConnect() { |
+ next_state_ = STATE_SEND_QUERY; |
+ return socket_->Connect(server_); |
+ } |
+ |
+ int DoSendQuery() { |
+ next_state_ = STATE_SEND_QUERY_COMPLETE; |
+ return socket_->Write(query_->io_buffer(), |
+ query_->io_buffer()->size(), |
+ base::Bind(&DnsUDPAttempt::OnIOComplete, |
+ base::Unretained(this))); |
+ } |
+ |
+ int DoSendQueryComplete(int rv) { |
+ if (rv < 0) |
+ return rv; |
+ |
+ // Writing to UDP should not result in a partial datagram. |
+ if (rv != query_->io_buffer()->size()) |
+ return ERR_MSG_TOO_BIG; |
+ |
+ next_state_ = STATE_READ_RESPONSE; |
+ return OK; |
+ } |
+ |
+ int DoReadResponse() { |
+ next_state_ = STATE_READ_RESPONSE_COMPLETE; |
+ response_.reset(new DnsResponse()); |
+ return socket_->Read(response_->io_buffer(), |
+ response_->io_buffer()->size(), |
+ base::Bind(&DnsUDPAttempt::OnIOComplete, |
+ base::Unretained(this))); |
+ } |
+ |
+ int DoReadResponseComplete(int rv) { |
+ DCHECK_NE(ERR_IO_PENDING, rv); |
+ if (rv < 0) |
+ return rv; |
+ |
+ DCHECK(rv); |
+ if (!response_->InitParse(rv, *query_)) |
+ return ERR_DNS_MALFORMED_RESPONSE; |
+ if (response_->flags() & dns_protocol::kFlagTC) |
+ return ERR_DNS_SERVER_REQUIRES_TCP; |
+ if (response_->rcode() != dns_protocol::kRcodeNOERROR && |
+ response_->rcode() != dns_protocol::kRcodeNXDOMAIN) { |
+ return ERR_DNS_SERVER_FAILED; |
+ } |
+ if (response_->answer_count() == 0) |
+ return ERR_NAME_NOT_RESOLVED; |
+ |
+ return OK; |
+ } |
+ |
+ void OnIOComplete(int rv) { |
+ rv = DoLoop(rv); |
+ if (rv != ERR_IO_PENDING) |
+ callback_.Run(rv); |
+ } |
+ |
+ State next_state_; |
+ |
+ scoped_ptr<DatagramClientSocket> socket_; |
+ IPEndPoint server_; |
+ scoped_ptr<DnsQuery> query_; |
+ |
+ scoped_ptr<DnsResponse> response_; |
+ |
+ CompletionCallback callback_; |
mmenke
2012/01/13 16:44:37
nit: DISALLOW_COPY_AND_ASSIGN
|
+}; |
+ |
+// ---------------------------------------------------------------------------- |
+ |
+// Implements DnsTransaction. Configuration is supplied by DnsSession. |
+// The suffix list is built according to the DnsConfig from the session. |
+// The timeout for each DnsUDPAttempt is given by DnsSession::NextTimeout. |
+// The first server to attempt on each query is given by |
+// DnsSession::NextFirstServerIndex, and the order is round-robin afterwards. |
+// Each server is attempted DnsConfig::attempts times. |
+class DnsTransactionImpl : public DnsTransaction, |
+ public base::NonThreadSafe, |
+ public base::SupportsWeakPtr<DnsTransactionImpl> { |
public: |
- class RequestImpl : public Request { |
- public: |
- RequestImpl(const base::StringPiece& qname, |
- uint16 qtype, |
- const RequestCallback& callback, |
- DnsSession* session, |
- const BoundNetLog& net_log) |
- : Request(qname, qtype, callback), |
- session_(session), |
- net_log_(net_log) { |
+ DnsTransactionImpl(DnsSession* session, |
+ const std::string& hostname, |
+ uint16 qtype, |
+ const DnsClient::CallbackType& callback, |
+ const BoundNetLog& source_net_log) |
+ : session_(session), |
+ hostname_(hostname), |
+ qtype_(qtype), |
+ callback_(callback), |
+ net_log_(BoundNetLog::Make(session->net_log(), |
+ NetLog::SOURCE_DNS_TRANSACTION)), |
+ successful_attempt_(NULL) { |
cbentzel
2012/01/13 13:39:54
first_server_index_ should be initialized - yeah,
|
+ DCHECK(session_); |
+ DCHECK(!hostname_.empty()); |
+ DCHECK(!callback_.is_null()); |
+ |
cbentzel
2012/01/13 13:39:54
Should this check if qtype is one of the known typ
|
+ net_log_.BeginEvent(NetLog::TYPE_DNS_TRANSACTION, make_scoped_refptr( |
+ new StartParameters(hostname_, qtype_, source_net_log.source()))); |
+ |
+ int rv = PrepareSearch(); |
cbentzel
2012/01/13 13:39:54
Not really sure if I like having all this in the c
szym
2012/01/13 15:43:40
Do you mean move PrepareSearch to Start? I'd rathe
cbentzel
2012/01/13 18:12:59
I did mean do it in DnsClient::CreateTransaction,
|
+ if (rv == OK) |
+ rv = StartQuery(); |
+ if (rv != ERR_IO_PENDING) { |
+ DCHECK_NE(OK, rv); |
+ DCHECK_NE(ERR_NAME_NOT_RESOLVED, rv); |
+ // Unexpected synchronous completion. Use WeakPtr in case the user |
+ // destroys the transaction before the task is executed. |
+ MessageLoop::current()->PostTask( |
+ FROM_HERE, |
+ base::Bind(&DnsTransactionImpl::DoCallback, AsWeakPtr(), rv)); |
} |
+ } |
- virtual int Start() OVERRIDE { |
- transaction_.reset(new DnsTransaction( |
- session_, |
- qname(), |
- qtype(), |
- base::Bind(&RequestImpl::OnComplete, base::Unretained(this)), |
- net_log_)); |
- return transaction_->Start(); |
+ virtual ~DnsTransactionImpl() { |
+ STLDeleteElements(&attempts_); |
+ if (!callback_.is_null()) { |
+ net_log_.AddEvent(NetLog::TYPE_CANCELLED, NULL); |
+ net_log_.EndEventWithNetErrorCode(NetLog::TYPE_DNS_TRANSACTION, |
+ ERR_ABORTED); |
} |
+ } |
+ |
+ virtual const std::string& GetHostname() const OVERRIDE { |
+ DCHECK(CalledOnValidThread()); |
+ return hostname_; |
+ } |
- void OnComplete(DnsTransaction* transaction, int rv) { |
- DCHECK_EQ(transaction_.get(), transaction); |
- // TODO(szym): |
- // - handle retransmissions here instead of DnsTransaction |
- // - handle rcode and flags here instead of DnsTransaction |
- // - update RTT in DnsSession |
- // - perform suffix search |
- // - handle DNS over TCP |
- DoCallback(rv, (rv == OK) ? transaction->response() : NULL); |
+ virtual uint16 GetType() const OVERRIDE { |
+ DCHECK(CalledOnValidThread()); |
+ return qtype_; |
+ } |
+ |
+ private: |
+ // Prepares |qnames_| according to the DnsConfig. |
+ int PrepareSearch() { |
+ const DnsConfig& config = session_->config(); |
+ |
+ std::string hostname; |
cbentzel
2012/01/13 13:39:54
It would be nice to use a better variable name tha
szym
2012/01/13 15:43:40
I could use dotted_hostname for the other case.
|
+ if (!DNSDomainFromDot(hostname_, &hostname)) |
+ return ERR_INVALID_ARGUMENT; |
+ |
+ if (hostname_[hostname_.size() - 1] == '.') { |
+ // It's a fully-qualified name, no suffix search. |
+ qnames_.push_back(hostname); |
+ return OK; |
} |
- private: |
- scoped_refptr<DnsSession> session_; |
- BoundNetLog net_log_; |
- scoped_ptr<DnsTransaction> transaction_; |
- }; |
+ // Set true when |hostname| is put on the list. |
+ bool had_hostname = false; |
+ |
+ int ndots = CountLabels(hostname) - 1; |
+ if (ndots >= config.ndots) { |
+ qnames_.push_back(hostname); |
+ had_hostname = true; |
+ } |
+ |
+ std::string qname; |
+ for (size_t i = 0; i < config.search.size(); ++i) { |
+ // Ignore invalid (too long) combinations. |
+ if (!DNSDomainFromDot(hostname_ + "." + config.search[i], &qname)) |
+ continue; |
+ if (qname.size() == hostname.size()) { |
cbentzel
2012/01/13 13:39:54
Interesting - is an empty suffix allowed? Or is th
szym
2012/01/13 15:43:40
DNSDomainFromDot always appends the root domain at
|
+ if (had_hostname) |
cbentzel
2012/01/13 13:39:54
Do you want to make this more generic in the loop
szym
2012/01/13 15:43:40
I think it'd make sense to do this filtering at th
|
+ continue; |
+ had_hostname = true; |
+ } |
+ qnames_.push_back(qname); |
+ } |
+ |
+ if (!had_hostname) |
+ qnames_.push_back(hostname); |
+ |
+ return OK; |
+ } |
+ |
+ void DoCallback(int rv) { |
+ if (callback_.is_null()) |
+ return; |
+ DCHECK_NE(ERR_IO_PENDING, rv); |
+ DCHECK(rv != OK || successful_attempt_ != NULL); |
+ |
+ DnsClient::CallbackType callback = callback_; |
+ callback_.Reset(); |
+ net_log_.EndEventWithNetErrorCode(NetLog::TYPE_DNS_TRANSACTION, rv); |
+ callback.Run(this, |
+ rv, |
+ successful_attempt_ ? successful_attempt_->response() : NULL); |
+ } |
+ |
+ // Makes another attempt at the current name, |qnames_.front()|, using the |
+ // next nameserver. |
+ int MakeAttempt() { |
+ int attempt_number = attempts_.size(); |
+ |
+ scoped_ptr<DatagramClientSocket> socket( |
+ session_->socket_factory()->CreateDatagramClientSocket( |
+ DatagramSocket::RANDOM_BIND, |
+ base::Bind(&base::RandInt), |
+ net_log_.net_log(), |
+ net_log_.source())); |
+ |
+ uint16 id = session_->NextQueryId(); |
+ scoped_ptr<DnsQuery> query; |
+ if (attempts_.empty()) { |
+ query.reset(new DnsQuery(id, qnames_.front(), qtype_)); |
+ } else { |
+ query.reset(attempts_[0]->query()->CloneWithNewId(id)); |
cbentzel
2012/01/13 13:39:54
Note to self: See if this any easier.
|
+ } |
+ |
+ net_log_.AddEvent(NetLog::TYPE_DNS_TRANSACTION_ATTEMPT, make_scoped_refptr( |
+ new NetLogSourceParameter("socket", socket->NetLog().source()))); |
mmenke
2012/01/13 16:44:37
Think it would be a little clearer if you also log
szym
2012/01/13 17:17:42
The reason why I don't include attempt_number is b
mmenke
2012/01/13 17:22:58
I was just thinking that it would be clearer for t
|
+ |
+ const DnsConfig& config = session_->config(); |
+ |
+ int server_index = first_server_index_ + |
cbentzel
2012/01/13 13:39:54
You should check for 0 length config.nameservers,
szym
2012/01/13 15:43:40
If |config.nameservers| is empty, the config is in
cbentzel
2012/01/13 18:12:59
What if the config changed while the DnsTransactio
szym
2012/01/13 20:06:17
DnsConfig is const in DnsSession, so DnsTransactio
|
+ (attempt_number % config.nameservers.size()); |
+ DnsUDPAttempt* attempt = new DnsUDPAttempt( |
+ socket.Pass(), |
+ config.nameservers[server_index], |
+ query.Pass(), |
+ base::Bind(&DnsTransactionImpl::OnAttemptComplete, |
+ base::Unretained(this), |
+ attempt_number)); |
+ |
+ base::TimeDelta timeout = session_->NextTimeout(attempt_number); |
+ timer_.Start(FROM_HERE, timeout, this, &DnsTransactionImpl::OnTimeout); |
+ attempts_.push_back(attempt); |
+ return attempt->Start(); |
+ } |
+ |
+ // Begins query for the current name. Makes the first attempt. |
+ int StartQuery() { |
+ std::string dotted_qname = DNSDomainToString(qnames_.front()); |
+ net_log_.BeginEvent( |
+ NetLog::TYPE_DNS_TRANSACTION_QUERY, |
mmenke
2012/01/13 17:16:24
Where do you log the corresponding end event?
|
+ make_scoped_refptr(new NetLogStringParameter("qname", dotted_qname))); |
+ |
+ first_server_index_ = session_->NextFirstServerIndex(); |
+ |
+ STLDeleteElements(&attempts_); |
+ return MakeAttempt(); |
+ } |
+ |
+ void OnAttemptComplete(int attempt_number, int rv) { |
+ timer_.Stop(); |
+ |
+ const DnsUDPAttempt* attempt = attempts_[attempt_number]; |
+ |
+ net_log_.AddEvent( |
+ NetLog::TYPE_DNS_TRANSACTION_RESPONSE, |
+ make_scoped_refptr( |
+ new NetLogSourceParameter("socket", |
+ attempt->socket()->NetLog().source()))); |
+ |
+ switch (rv) { |
+ case ERR_NAME_NOT_RESOLVED: |
+ // Try next suffix. |
+ qnames_.pop_front(); |
+ if (qnames_.empty()) |
+ rv = ERR_NAME_NOT_RESOLVED; |
+ else |
+ rv = StartQuery(); |
+ break; |
+ case OK: |
+ successful_attempt_ = attempt; |
+ break; |
+ default: |
+ // TODO(szym): Some nameservers could fail and we should just ignore |
+ // them. |
+ break; |
+ } |
+ if (rv != ERR_IO_PENDING) |
+ DoCallback(rv); |
+ } |
+ |
+ void OnTimeout() { |
+ const DnsConfig& config = session_->config(); |
+ if (attempts_.size() == config.attempts * config.nameservers.size()) { |
+ DoCallback(ERR_DNS_TIMED_OUT); |
+ return; |
+ } |
+ int rv = MakeAttempt(); |
+ if (rv != ERR_IO_PENDING) |
+ DoCallback(rv); |
+ } |
+ |
+ scoped_refptr<DnsSession> session_; |
+ std::string hostname_; |
+ uint16 qtype_; |
+ // Set to NULL once the transaction completes. |
cbentzel
2012/01/13 13:39:54
Nit: perhaps null instead of NULL - NULL implies p
|
+ DnsClient::CallbackType callback_; |
+ |
+ BoundNetLog net_log_; |
+ |
+ // Search list of fully-qualified DNS names to query next (in DNS format). |
+ std::deque<std::string> qnames_; |
cbentzel
2012/01/13 13:39:54
deque not really needed here, since just doing pus
szym
2012/01/13 15:43:40
Need qnames_.pop_front().
|
+ |
+ // List of attempts for the current name. |
+ std::vector<DnsUDPAttempt*> attempts_; |
+ // The one of the |attempts_| that succeeded first. |
mmenke
2012/01/13 16:44:37
Nit: This is the member of |attempts_| that succe
|
+ const DnsUDPAttempt* successful_attempt_; |
+ |
+ // Index of the first server to try on each search query. |
+ int first_server_index_; |
+ |
+ base::OneShotTimer<DnsTransactionImpl> timer_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(DnsTransactionImpl); |
+}; |
+ |
+// ---------------------------------------------------------------------------- |
+ |
+// Implementation of DnsClient that returns instances of DnsTransactionImpl. |
+class DnsClientImpl : public DnsClient { |
mmenke
2012/01/13 16:44:37
Is there a compelling reason to keep DnsClient and
szym
2012/01/13 17:17:42
The reason I'd keep them separate is so that we ca
mmenke
2012/01/13 17:22:58
Ah, right. Sounds good to me.
|
+ public: |
explicit DnsClientImpl(DnsSession* session) { |
session_ = session; |
} |
- virtual Request* CreateRequest( |
- const base::StringPiece& qname, |
+ virtual scoped_ptr<DnsTransaction> CreateTransaction( |
+ const std::string& hostname, |
uint16 qtype, |
- const RequestCallback& callback, |
+ const CallbackType& callback, |
const BoundNetLog& source_net_log) OVERRIDE { |
- return new RequestImpl(qname, qtype, callback, session_, source_net_log); |
+ return scoped_ptr<DnsTransaction>(new DnsTransactionImpl(session_, |
+ hostname, |
+ qtype, |
+ callback, |
+ source_net_log)); |
} |
private: |
scoped_refptr<DnsSession> session_; |
}; |
+} // namespace |
+ |
// static |
-DnsClient* DnsClient::CreateClient(DnsSession* session) { |
- return new DnsClientImpl(session); |
+scoped_ptr<DnsClient> DnsClient::CreateClient(DnsSession* session) { |
+ return scoped_ptr<DnsClient>(new DnsClientImpl(session)); |
} |
} // namespace net |