2 * Copyright 2016 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #include <folly/io/async/AsyncSocket.h>
19 #include <folly/ExceptionWrapper.h>
20 #include <folly/SocketAddress.h>
21 #include <folly/io/IOBuf.h>
22 #include <folly/Portability.h>
23 #include <folly/portability/Fcntl.h>
24 #include <folly/portability/Sockets.h>
25 #include <folly/portability/SysUio.h>
26 #include <folly/portability/Unistd.h>
31 #include <sys/types.h>
32 #include <boost/preprocessor/control/if.hpp>
35 using std::unique_ptr;
37 namespace fsp = folly::portability::sockets;
41 // static members initializers
42 const AsyncSocket::OptionMap AsyncSocket::emptyOptionMap;
44 const AsyncSocketException socketClosedLocallyEx(
45 AsyncSocketException::END_OF_FILE, "socket closed locally");
46 const AsyncSocketException socketShutdownForWritesEx(
47 AsyncSocketException::END_OF_FILE, "socket shutdown for writes");
49 // TODO: It might help performance to provide a version of BytesWriteRequest that
50 // users could derive from, so we can avoid the extra allocation for each call
51 // to write()/writev(). We could templatize TFramedAsyncChannel just like the
52 // protocols are currently templatized for transports.
54 // We would need the version for external users where they provide the iovec
55 // storage space, and only our internal version would allocate it at the end of
58 /* The default WriteRequest implementation, used for write(), writev() and
61 * A new BytesWriteRequest operation is allocated on the heap for all write
62 * operations that cannot be completed immediately.
64 class AsyncSocket::BytesWriteRequest : public AsyncSocket::WriteRequest {
66 static BytesWriteRequest* newRequest(AsyncSocket* socket,
67 WriteCallback* callback,
70 uint32_t partialWritten,
71 uint32_t bytesWritten,
72 unique_ptr<IOBuf>&& ioBuf,
75 // Since we put a variable size iovec array at the end
76 // of each BytesWriteRequest, we have to manually allocate the memory.
77 void* buf = malloc(sizeof(BytesWriteRequest) +
78 (opCount * sizeof(struct iovec)));
80 throw std::bad_alloc();
83 return new(buf) BytesWriteRequest(socket, callback, ops, opCount,
84 partialWritten, bytesWritten,
85 std::move(ioBuf), flags);
88 void destroy() override {
89 this->~BytesWriteRequest();
93 WriteResult performWrite() override {
94 WriteFlags writeFlags = flags_;
95 if (getNext() != nullptr) {
96 writeFlags = writeFlags | WriteFlags::CORK;
98 auto writeResult = socket_->performWrite(
99 getOps(), getOpCount(), writeFlags, &opsWritten_, &partialBytes_);
100 bytesWritten_ = writeResult.writeReturn > 0 ? writeResult.writeReturn : 0;
104 bool isComplete() override {
105 return opsWritten_ == getOpCount();
108 void consume() override {
109 // Advance opIndex_ forward by opsWritten_
110 opIndex_ += opsWritten_;
111 assert(opIndex_ < opCount_);
113 // If we've finished writing any IOBufs, release them
115 for (uint32_t i = opsWritten_; i != 0; --i) {
117 ioBuf_ = ioBuf_->pop();
121 // Move partialBytes_ forward into the current iovec buffer
122 struct iovec* currentOp = writeOps_ + opIndex_;
123 assert((partialBytes_ < currentOp->iov_len) || (currentOp->iov_len == 0));
124 currentOp->iov_base =
125 reinterpret_cast<uint8_t*>(currentOp->iov_base) + partialBytes_;
126 currentOp->iov_len -= partialBytes_;
128 // Increment the totalBytesWritten_ count by bytesWritten_;
129 assert(bytesWritten_ >= 0);
130 totalBytesWritten_ += uint32_t(bytesWritten_);
134 BytesWriteRequest(AsyncSocket* socket,
135 WriteCallback* callback,
136 const struct iovec* ops,
138 uint32_t partialBytes,
139 uint32_t bytesWritten,
140 unique_ptr<IOBuf>&& ioBuf,
142 : AsyncSocket::WriteRequest(socket, callback)
146 , ioBuf_(std::move(ioBuf))
148 , partialBytes_(partialBytes)
149 , bytesWritten_(bytesWritten) {
150 memcpy(writeOps_, ops, sizeof(*ops) * opCount_);
153 // private destructor, to ensure callers use destroy()
154 ~BytesWriteRequest() override = default;
156 const struct iovec* getOps() const {
157 assert(opCount_ > opIndex_);
158 return writeOps_ + opIndex_;
161 uint32_t getOpCount() const {
162 assert(opCount_ > opIndex_);
163 return opCount_ - opIndex_;
166 uint32_t opCount_; ///< number of entries in writeOps_
167 uint32_t opIndex_; ///< current index into writeOps_
168 WriteFlags flags_; ///< set for WriteFlags
169 unique_ptr<IOBuf> ioBuf_; ///< underlying IOBuf, or nullptr if N/A
171 // for consume(), how much we wrote on the last write
172 uint32_t opsWritten_; ///< complete ops written
173 uint32_t partialBytes_; ///< partial bytes of incomplete op written
174 ssize_t bytesWritten_; ///< bytes written altogether
176 struct iovec writeOps_[]; ///< write operation(s) list
179 AsyncSocket::AsyncSocket()
180 : eventBase_(nullptr),
181 writeTimeout_(this, nullptr),
182 ioHandler_(this, nullptr),
183 immediateReadHandler_(this) {
184 VLOG(5) << "new AsyncSocket()";
188 AsyncSocket::AsyncSocket(EventBase* evb)
190 writeTimeout_(this, evb),
191 ioHandler_(this, evb),
192 immediateReadHandler_(this) {
193 VLOG(5) << "new AsyncSocket(" << this << ", evb=" << evb << ")";
197 AsyncSocket::AsyncSocket(EventBase* evb,
198 const folly::SocketAddress& address,
199 uint32_t connectTimeout)
201 connect(nullptr, address, connectTimeout);
204 AsyncSocket::AsyncSocket(EventBase* evb,
205 const std::string& ip,
207 uint32_t connectTimeout)
209 connect(nullptr, ip, port, connectTimeout);
212 AsyncSocket::AsyncSocket(EventBase* evb, int fd)
214 writeTimeout_(this, evb),
215 ioHandler_(this, evb, fd),
216 immediateReadHandler_(this) {
217 VLOG(5) << "new AsyncSocket(" << this << ", evb=" << evb << ", fd="
222 state_ = StateEnum::ESTABLISHED;
225 // init() method, since constructor forwarding isn't supported in most
227 void AsyncSocket::init() {
228 assert(eventBase_ == nullptr || eventBase_->isInEventBaseThread());
230 state_ = StateEnum::UNINIT;
231 eventFlags_ = EventHandler::NONE;
234 maxReadsPerEvent_ = 16;
235 connectCallback_ = nullptr;
236 readCallback_ = nullptr;
237 writeReqHead_ = nullptr;
238 writeReqTail_ = nullptr;
239 shutdownSocketSet_ = nullptr;
240 appBytesWritten_ = 0;
241 appBytesReceived_ = 0;
244 AsyncSocket::~AsyncSocket() {
245 VLOG(7) << "actual destruction of AsyncSocket(this=" << this
246 << ", evb=" << eventBase_ << ", fd=" << fd_
247 << ", state=" << state_ << ")";
250 void AsyncSocket::destroy() {
251 VLOG(5) << "AsyncSocket::destroy(this=" << this << ", evb=" << eventBase_
252 << ", fd=" << fd_ << ", state=" << state_;
253 // When destroy is called, close the socket immediately
256 // Then call DelayedDestruction::destroy() to take care of
257 // whether or not we need immediate or delayed destruction
258 DelayedDestruction::destroy();
261 int AsyncSocket::detachFd() {
262 VLOG(6) << "AsyncSocket::detachFd(this=" << this << ", fd=" << fd_
263 << ", evb=" << eventBase_ << ", state=" << state_
264 << ", events=" << std::hex << eventFlags_ << ")";
265 // Extract the fd, and set fd_ to -1 first, so closeNow() won't
266 // actually close the descriptor.
267 if (shutdownSocketSet_) {
268 shutdownSocketSet_->remove(fd_);
272 // Call closeNow() to invoke all pending callbacks with an error.
274 // Update the EventHandler to stop using this fd.
275 // This can only be done after closeNow() unregisters the handler.
276 ioHandler_.changeHandlerFD(-1);
280 const folly::SocketAddress& AsyncSocket::anyAddress() {
281 static const folly::SocketAddress anyAddress =
282 folly::SocketAddress("0.0.0.0", 0);
286 void AsyncSocket::setShutdownSocketSet(ShutdownSocketSet* newSS) {
287 if (shutdownSocketSet_ == newSS) {
290 if (shutdownSocketSet_ && fd_ != -1) {
291 shutdownSocketSet_->remove(fd_);
293 shutdownSocketSet_ = newSS;
294 if (shutdownSocketSet_ && fd_ != -1) {
295 shutdownSocketSet_->add(fd_);
299 void AsyncSocket::setCloseOnExec() {
300 int rv = fcntl(fd_, F_SETFD, FD_CLOEXEC);
302 auto errnoCopy = errno;
303 throw AsyncSocketException(
304 AsyncSocketException::INTERNAL_ERROR,
305 withAddr("failed to set close-on-exec flag"),
310 void AsyncSocket::connect(ConnectCallback* callback,
311 const folly::SocketAddress& address,
313 const OptionMap &options,
314 const folly::SocketAddress& bindAddr) noexcept {
315 DestructorGuard dg(this);
316 assert(eventBase_->isInEventBaseThread());
320 // Make sure we're in the uninitialized state
321 if (state_ != StateEnum::UNINIT) {
322 return invalidState(callback);
325 connectTimeout_ = std::chrono::milliseconds(timeout);
326 connectStartTime_ = std::chrono::steady_clock::now();
327 // Make connect end time at least >= connectStartTime.
328 connectEndTime_ = connectStartTime_;
331 state_ = StateEnum::CONNECTING;
332 connectCallback_ = callback;
334 sockaddr_storage addrStorage;
335 sockaddr* saddr = reinterpret_cast<sockaddr*>(&addrStorage);
339 // Technically the first parameter should actually be a protocol family
340 // constant (PF_xxx) rather than an address family (AF_xxx), but the
341 // distinction is mainly just historical. In pretty much all
342 // implementations the PF_foo and AF_foo constants are identical.
343 fd_ = fsp::socket(address.getFamily(), SOCK_STREAM, 0);
345 auto errnoCopy = errno;
346 throw AsyncSocketException(
347 AsyncSocketException::INTERNAL_ERROR,
348 withAddr("failed to create socket"),
351 if (shutdownSocketSet_) {
352 shutdownSocketSet_->add(fd_);
354 ioHandler_.changeHandlerFD(fd_);
358 // Put the socket in non-blocking mode
359 int flags = fcntl(fd_, F_GETFL, 0);
361 auto errnoCopy = errno;
362 throw AsyncSocketException(
363 AsyncSocketException::INTERNAL_ERROR,
364 withAddr("failed to get socket flags"),
367 int rv = fcntl(fd_, F_SETFL, flags | O_NONBLOCK);
369 auto errnoCopy = errno;
370 throw AsyncSocketException(
371 AsyncSocketException::INTERNAL_ERROR,
372 withAddr("failed to put socket in non-blocking mode"),
376 #if !defined(MSG_NOSIGNAL) && defined(F_SETNOSIGPIPE)
377 // iOS and OS X don't support MSG_NOSIGNAL; set F_SETNOSIGPIPE instead
378 rv = fcntl(fd_, F_SETNOSIGPIPE, 1);
380 auto errnoCopy = errno;
381 throw AsyncSocketException(
382 AsyncSocketException::INTERNAL_ERROR,
383 "failed to enable F_SETNOSIGPIPE on socket",
388 // By default, turn on TCP_NODELAY
389 // If setNoDelay() fails, we continue anyway; this isn't a fatal error.
390 // setNoDelay() will log an error message if it fails.
391 if (address.getFamily() != AF_UNIX) {
392 (void)setNoDelay(true);
395 VLOG(5) << "AsyncSocket::connect(this=" << this << ", evb=" << eventBase_
396 << ", fd=" << fd_ << ", host=" << address.describe().c_str();
399 if (bindAddr != anyAddress()) {
401 if (setsockopt(fd_, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one))) {
402 auto errnoCopy = errno;
404 throw AsyncSocketException(
405 AsyncSocketException::NOT_OPEN,
406 "failed to setsockopt prior to bind on " + bindAddr.describe(),
410 bindAddr.getAddress(&addrStorage);
412 if (bind(fd_, saddr, bindAddr.getActualSize()) != 0) {
413 auto errnoCopy = errno;
415 throw AsyncSocketException(
416 AsyncSocketException::NOT_OPEN,
417 "failed to bind to async socket: " + bindAddr.describe(),
422 // Apply the additional options if any.
423 for (const auto& opt: options) {
424 rv = opt.first.apply(fd_, opt.second);
426 auto errnoCopy = errno;
427 throw AsyncSocketException(
428 AsyncSocketException::INTERNAL_ERROR,
429 withAddr("failed to set socket option"),
434 // Perform the connect()
435 address.getAddress(&addrStorage);
438 state_ = StateEnum::FAST_OPEN;
439 tfoAttempted_ = true;
441 if (socketConnect(saddr, addr_.getActualSize()) < 0) {
446 // If we're still here the connect() succeeded immediately.
447 // Fall through to call the callback outside of this try...catch block
448 } catch (const AsyncSocketException& ex) {
449 return failConnect(__func__, ex);
450 } catch (const std::exception& ex) {
451 // shouldn't happen, but handle it just in case
452 VLOG(4) << "AsyncSocket::connect(this=" << this << ", fd=" << fd_
453 << "): unexpected " << typeid(ex).name() << " exception: "
455 AsyncSocketException tex(AsyncSocketException::INTERNAL_ERROR,
456 withAddr(string("unexpected exception: ") +
458 return failConnect(__func__, tex);
461 // The connection succeeded immediately
462 // The read callback may not have been set yet, and no writes may be pending
463 // yet, so we don't have to register for any events at the moment.
464 VLOG(8) << "AsyncSocket::connect succeeded immediately; this=" << this;
465 assert(readCallback_ == nullptr);
466 assert(writeReqHead_ == nullptr);
467 if (state_ != StateEnum::FAST_OPEN) {
468 state_ = StateEnum::ESTABLISHED;
470 invokeConnectSuccess();
473 int AsyncSocket::socketConnect(const struct sockaddr* saddr, socklen_t len) {
474 int rv = fsp::connect(fd_, saddr, len);
476 auto errnoCopy = errno;
477 if (errnoCopy == EINPROGRESS) {
478 scheduleConnectTimeout();
479 registerForConnectEvents();
481 throw AsyncSocketException(
482 AsyncSocketException::NOT_OPEN,
483 "connect failed (immediately)",
490 void AsyncSocket::scheduleConnectTimeout() {
491 // Connection in progress.
492 int timeout = connectTimeout_.count();
494 // Start a timer in case the connection takes too long.
495 if (!writeTimeout_.scheduleTimeout(timeout)) {
496 throw AsyncSocketException(
497 AsyncSocketException::INTERNAL_ERROR,
498 withAddr("failed to schedule AsyncSocket connect timeout"));
503 void AsyncSocket::registerForConnectEvents() {
504 // Register for write events, so we'll
505 // be notified when the connection finishes/fails.
506 // Note that we don't register for a persistent event here.
507 assert(eventFlags_ == EventHandler::NONE);
508 eventFlags_ = EventHandler::WRITE;
509 if (!ioHandler_.registerHandler(eventFlags_)) {
510 throw AsyncSocketException(
511 AsyncSocketException::INTERNAL_ERROR,
512 withAddr("failed to register AsyncSocket connect handler"));
516 void AsyncSocket::connect(ConnectCallback* callback,
517 const string& ip, uint16_t port,
519 const OptionMap &options) noexcept {
520 DestructorGuard dg(this);
522 connectCallback_ = callback;
523 connect(callback, folly::SocketAddress(ip, port), timeout, options);
524 } catch (const std::exception& ex) {
525 AsyncSocketException tex(AsyncSocketException::INTERNAL_ERROR,
527 return failConnect(__func__, tex);
531 void AsyncSocket::cancelConnect() {
532 connectCallback_ = nullptr;
533 if (state_ == StateEnum::CONNECTING || state_ == StateEnum::FAST_OPEN) {
538 void AsyncSocket::setSendTimeout(uint32_t milliseconds) {
539 sendTimeout_ = milliseconds;
540 assert(eventBase_ == nullptr || eventBase_->isInEventBaseThread());
542 // If we are currently pending on write requests, immediately update
543 // writeTimeout_ with the new value.
544 if ((eventFlags_ & EventHandler::WRITE) &&
545 (state_ != StateEnum::CONNECTING && state_ != StateEnum::FAST_OPEN)) {
546 assert(state_ == StateEnum::ESTABLISHED);
547 assert((shutdownFlags_ & SHUT_WRITE) == 0);
548 if (sendTimeout_ > 0) {
549 if (!writeTimeout_.scheduleTimeout(sendTimeout_)) {
550 AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
551 withAddr("failed to reschedule send timeout in setSendTimeout"));
552 return failWrite(__func__, ex);
555 writeTimeout_.cancelTimeout();
560 void AsyncSocket::setReadCB(ReadCallback *callback) {
561 VLOG(6) << "AsyncSocket::setReadCallback() this=" << this << ", fd=" << fd_
562 << ", callback=" << callback << ", state=" << state_;
564 // Short circuit if callback is the same as the existing readCallback_.
566 // Note that this is needed for proper functioning during some cleanup cases.
567 // During cleanup we allow setReadCallback(nullptr) to be called even if the
568 // read callback is already unset and we have been detached from an event
569 // base. This check prevents us from asserting
570 // eventBase_->isInEventBaseThread() when eventBase_ is nullptr.
571 if (callback == readCallback_) {
575 /* We are removing a read callback */
576 if (callback == nullptr &&
577 immediateReadHandler_.isLoopCallbackScheduled()) {
578 immediateReadHandler_.cancelLoopCallback();
581 if (shutdownFlags_ & SHUT_READ) {
582 // Reads have already been shut down on this socket.
584 // Allow setReadCallback(nullptr) to be called in this case, but don't
585 // allow a new callback to be set.
587 // For example, setReadCallback(nullptr) can happen after an error if we
588 // invoke some other error callback before invoking readError(). The other
589 // error callback that is invoked first may go ahead and clear the read
590 // callback before we get a chance to invoke readError().
591 if (callback != nullptr) {
592 return invalidState(callback);
594 assert((eventFlags_ & EventHandler::READ) == 0);
595 readCallback_ = nullptr;
599 DestructorGuard dg(this);
600 assert(eventBase_->isInEventBaseThread());
602 switch ((StateEnum)state_) {
603 case StateEnum::CONNECTING:
604 case StateEnum::FAST_OPEN:
605 // For convenience, we allow the read callback to be set while we are
606 // still connecting. We just store the callback for now. Once the
607 // connection completes we'll register for read events.
608 readCallback_ = callback;
610 case StateEnum::ESTABLISHED:
612 readCallback_ = callback;
613 uint16_t oldFlags = eventFlags_;
615 eventFlags_ |= EventHandler::READ;
617 eventFlags_ &= ~EventHandler::READ;
620 // Update our registration if our flags have changed
621 if (eventFlags_ != oldFlags) {
622 // We intentionally ignore the return value here.
623 // updateEventRegistration() will move us into the error state if it
624 // fails, and we don't need to do anything else here afterwards.
625 (void)updateEventRegistration();
629 checkForImmediateRead();
633 case StateEnum::CLOSED:
634 case StateEnum::ERROR:
635 // We should never reach here. SHUT_READ should always be set
636 // if we are in STATE_CLOSED or STATE_ERROR.
638 return invalidState(callback);
639 case StateEnum::UNINIT:
640 // We do not allow setReadCallback() to be called before we start
642 return invalidState(callback);
645 // We don't put a default case in the switch statement, so that the compiler
646 // will warn us to update the switch statement if a new state is added.
647 return invalidState(callback);
650 AsyncSocket::ReadCallback* AsyncSocket::getReadCallback() const {
651 return readCallback_;
654 void AsyncSocket::write(WriteCallback* callback,
655 const void* buf, size_t bytes, WriteFlags flags) {
657 op.iov_base = const_cast<void*>(buf);
659 writeImpl(callback, &op, 1, unique_ptr<IOBuf>(), flags);
662 void AsyncSocket::writev(WriteCallback* callback,
666 writeImpl(callback, vec, count, unique_ptr<IOBuf>(), flags);
669 void AsyncSocket::writeChain(WriteCallback* callback, unique_ptr<IOBuf>&& buf,
671 constexpr size_t kSmallSizeMax = 64;
672 size_t count = buf->countChainElements();
673 if (count <= kSmallSizeMax) {
674 // suppress "warning: variable length array 'vec' is used [-Wvla]"
676 FOLLY_GCC_DISABLE_WARNING(vla);
677 iovec vec[BOOST_PP_IF(FOLLY_HAVE_VLA, count, kSmallSizeMax)];
680 writeChainImpl(callback, vec, count, std::move(buf), flags);
682 iovec* vec = new iovec[count];
683 writeChainImpl(callback, vec, count, std::move(buf), flags);
688 void AsyncSocket::writeChainImpl(WriteCallback* callback, iovec* vec,
689 size_t count, unique_ptr<IOBuf>&& buf, WriteFlags flags) {
690 size_t veclen = buf->fillIov(vec, count);
691 writeImpl(callback, vec, veclen, std::move(buf), flags);
694 void AsyncSocket::writeImpl(WriteCallback* callback, const iovec* vec,
695 size_t count, unique_ptr<IOBuf>&& buf,
697 VLOG(6) << "AsyncSocket::writev() this=" << this << ", fd=" << fd_
698 << ", callback=" << callback << ", count=" << count
699 << ", state=" << state_;
700 DestructorGuard dg(this);
701 unique_ptr<IOBuf>ioBuf(std::move(buf));
702 assert(eventBase_->isInEventBaseThread());
704 if (shutdownFlags_ & (SHUT_WRITE | SHUT_WRITE_PENDING)) {
705 // No new writes may be performed after the write side of the socket has
708 // We could just call callback->writeError() here to fail just this write.
709 // However, fail hard and use invalidState() to fail all outstanding
710 // callbacks and move the socket into the error state. There's most likely
711 // a bug in the caller's code, so we abort everything rather than trying to
712 // proceed as best we can.
713 return invalidState(callback);
716 uint32_t countWritten = 0;
717 uint32_t partialWritten = 0;
718 int bytesWritten = 0;
719 bool mustRegister = false;
720 if ((state_ == StateEnum::ESTABLISHED || state_ == StateEnum::FAST_OPEN) &&
722 if (writeReqHead_ == nullptr) {
723 // If we are established and there are no other writes pending,
724 // we can attempt to perform the write immediately.
725 assert(writeReqTail_ == nullptr);
726 assert((eventFlags_ & EventHandler::WRITE) == 0);
729 performWrite(vec, count, flags, &countWritten, &partialWritten);
730 bytesWritten = writeResult.writeReturn;
731 if (bytesWritten < 0) {
732 auto errnoCopy = errno;
733 if (writeResult.exception) {
734 return failWrite(__func__, callback, 0, *writeResult.exception);
736 AsyncSocketException ex(
737 AsyncSocketException::INTERNAL_ERROR,
738 withAddr("writev failed"),
740 return failWrite(__func__, callback, 0, ex);
741 } else if (countWritten == count) {
742 // We successfully wrote everything.
743 // Invoke the callback and return.
745 callback->writeSuccess();
748 } else { // continue writing the next writeReq
749 if (bufferCallback_) {
750 bufferCallback_->onEgressBuffered();
754 // Writes might put the socket back into connecting state
755 // if TFO is enabled, and using TFO fails.
756 // This means that write timeouts would not be active, however
757 // connect timeouts would affect this stage.
761 } else if (!connecting()) {
762 // Invalid state for writing
763 return invalidState(callback);
766 // Create a new WriteRequest to add to the queue
769 req = BytesWriteRequest::newRequest(this, callback, vec + countWritten,
770 count - countWritten, partialWritten,
771 bytesWritten, std::move(ioBuf), flags);
772 } catch (const std::exception& ex) {
773 // we mainly expect to catch std::bad_alloc here
774 AsyncSocketException tex(AsyncSocketException::INTERNAL_ERROR,
775 withAddr(string("failed to append new WriteRequest: ") + ex.what()));
776 return failWrite(__func__, callback, bytesWritten, tex);
779 if (writeReqTail_ == nullptr) {
780 assert(writeReqHead_ == nullptr);
781 writeReqHead_ = writeReqTail_ = req;
783 writeReqTail_->append(req);
787 // Register for write events if are established and not currently
788 // waiting on write events
790 assert(state_ == StateEnum::ESTABLISHED);
791 assert((eventFlags_ & EventHandler::WRITE) == 0);
792 if (!updateEventRegistration(EventHandler::WRITE, 0)) {
793 assert(state_ == StateEnum::ERROR);
796 if (sendTimeout_ > 0) {
797 // Schedule a timeout to fire if the write takes too long.
798 if (!writeTimeout_.scheduleTimeout(sendTimeout_)) {
799 AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
800 withAddr("failed to schedule send timeout"));
801 return failWrite(__func__, ex);
807 void AsyncSocket::writeRequest(WriteRequest* req) {
808 if (writeReqTail_ == nullptr) {
809 assert(writeReqHead_ == nullptr);
810 writeReqHead_ = writeReqTail_ = req;
813 writeReqTail_->append(req);
818 void AsyncSocket::close() {
819 VLOG(5) << "AsyncSocket::close(): this=" << this << ", fd_=" << fd_
820 << ", state=" << state_ << ", shutdownFlags="
821 << std::hex << (int) shutdownFlags_;
823 // close() is only different from closeNow() when there are pending writes
824 // that need to drain before we can close. In all other cases, just call
827 // Note that writeReqHead_ can be non-nullptr even in STATE_CLOSED or
828 // STATE_ERROR if close() is invoked while a previous closeNow() or failure
829 // is still running. (e.g., If there are multiple pending writes, and we
830 // call writeError() on the first one, it may call close(). In this case we
831 // will already be in STATE_CLOSED or STATE_ERROR, but the remaining pending
832 // writes will still be in the queue.)
834 // We only need to drain pending writes if we are still in STATE_CONNECTING
835 // or STATE_ESTABLISHED
836 if ((writeReqHead_ == nullptr) ||
837 !(state_ == StateEnum::CONNECTING ||
838 state_ == StateEnum::ESTABLISHED)) {
843 // Declare a DestructorGuard to ensure that the AsyncSocket cannot be
844 // destroyed until close() returns.
845 DestructorGuard dg(this);
846 assert(eventBase_->isInEventBaseThread());
848 // Since there are write requests pending, we have to set the
849 // SHUT_WRITE_PENDING flag, and wait to perform the real close until the
850 // connect finishes and we finish writing these requests.
852 // Set SHUT_READ to indicate that reads are shut down, and set the
853 // SHUT_WRITE_PENDING flag to mark that we want to shutdown once the
854 // pending writes complete.
855 shutdownFlags_ |= (SHUT_READ | SHUT_WRITE_PENDING);
857 // If a read callback is set, invoke readEOF() immediately to inform it that
858 // the socket has been closed and no more data can be read.
860 // Disable reads if they are enabled
861 if (!updateEventRegistration(0, EventHandler::READ)) {
862 // We're now in the error state; callbacks have been cleaned up
863 assert(state_ == StateEnum::ERROR);
864 assert(readCallback_ == nullptr);
866 ReadCallback* callback = readCallback_;
867 readCallback_ = nullptr;
873 void AsyncSocket::closeNow() {
874 VLOG(5) << "AsyncSocket::closeNow(): this=" << this << ", fd_=" << fd_
875 << ", state=" << state_ << ", shutdownFlags="
876 << std::hex << (int) shutdownFlags_;
877 DestructorGuard dg(this);
878 assert(eventBase_ == nullptr || eventBase_->isInEventBaseThread());
881 case StateEnum::ESTABLISHED:
882 case StateEnum::CONNECTING:
883 case StateEnum::FAST_OPEN: {
884 shutdownFlags_ |= (SHUT_READ | SHUT_WRITE);
885 state_ = StateEnum::CLOSED;
887 // If the write timeout was set, cancel it.
888 writeTimeout_.cancelTimeout();
890 // If we are registered for I/O events, unregister.
891 if (eventFlags_ != EventHandler::NONE) {
892 eventFlags_ = EventHandler::NONE;
893 if (!updateEventRegistration()) {
894 // We will have been moved into the error state.
895 assert(state_ == StateEnum::ERROR);
900 if (immediateReadHandler_.isLoopCallbackScheduled()) {
901 immediateReadHandler_.cancelLoopCallback();
905 ioHandler_.changeHandlerFD(-1);
909 invokeConnectErr(socketClosedLocallyEx);
911 failAllWrites(socketClosedLocallyEx);
914 ReadCallback* callback = readCallback_;
915 readCallback_ = nullptr;
920 case StateEnum::CLOSED:
921 // Do nothing. It's possible that we are being called recursively
922 // from inside a callback that we invoked inside another call to close()
923 // that is still running.
925 case StateEnum::ERROR:
926 // Do nothing. The error handling code has performed (or is performing)
929 case StateEnum::UNINIT:
930 assert(eventFlags_ == EventHandler::NONE);
931 assert(connectCallback_ == nullptr);
932 assert(readCallback_ == nullptr);
933 assert(writeReqHead_ == nullptr);
934 shutdownFlags_ |= (SHUT_READ | SHUT_WRITE);
935 state_ = StateEnum::CLOSED;
939 LOG(DFATAL) << "AsyncSocket::closeNow() (this=" << this << ", fd=" << fd_
940 << ") called in unknown state " << state_;
943 void AsyncSocket::closeWithReset() {
944 // Enable SO_LINGER, with the linger timeout set to 0.
945 // This will trigger a TCP reset when we close the socket.
947 struct linger optLinger = {1, 0};
948 if (setSockOpt(SOL_SOCKET, SO_LINGER, &optLinger) != 0) {
949 VLOG(2) << "AsyncSocket::closeWithReset(): error setting SO_LINGER "
950 << "on " << fd_ << ": errno=" << errno;
954 // Then let closeNow() take care of the rest
958 void AsyncSocket::shutdownWrite() {
959 VLOG(5) << "AsyncSocket::shutdownWrite(): this=" << this << ", fd=" << fd_
960 << ", state=" << state_ << ", shutdownFlags="
961 << std::hex << (int) shutdownFlags_;
963 // If there are no pending writes, shutdownWrite() is identical to
964 // shutdownWriteNow().
965 if (writeReqHead_ == nullptr) {
970 assert(eventBase_->isInEventBaseThread());
972 // There are pending writes. Set SHUT_WRITE_PENDING so that the actual
973 // shutdown will be performed once all writes complete.
974 shutdownFlags_ |= SHUT_WRITE_PENDING;
977 void AsyncSocket::shutdownWriteNow() {
978 VLOG(5) << "AsyncSocket::shutdownWriteNow(): this=" << this
979 << ", fd=" << fd_ << ", state=" << state_
980 << ", shutdownFlags=" << std::hex << (int) shutdownFlags_;
982 if (shutdownFlags_ & SHUT_WRITE) {
983 // Writes are already shutdown; nothing else to do.
987 // If SHUT_READ is already set, just call closeNow() to completely
988 // close the socket. This can happen if close() was called with writes
989 // pending, and then shutdownWriteNow() is called before all pending writes
991 if (shutdownFlags_ & SHUT_READ) {
996 DestructorGuard dg(this);
997 assert(eventBase_ == nullptr || eventBase_->isInEventBaseThread());
999 switch (static_cast<StateEnum>(state_)) {
1000 case StateEnum::ESTABLISHED:
1002 shutdownFlags_ |= SHUT_WRITE;
1004 // If the write timeout was set, cancel it.
1005 writeTimeout_.cancelTimeout();
1007 // If we are registered for write events, unregister.
1008 if (!updateEventRegistration(0, EventHandler::WRITE)) {
1009 // We will have been moved into the error state.
1010 assert(state_ == StateEnum::ERROR);
1014 // Shutdown writes on the file descriptor
1015 shutdown(fd_, SHUT_WR);
1017 // Immediately fail all write requests
1018 failAllWrites(socketShutdownForWritesEx);
1021 case StateEnum::CONNECTING:
1023 // Set the SHUT_WRITE_PENDING flag.
1024 // When the connection completes, it will check this flag,
1025 // shutdown the write half of the socket, and then set SHUT_WRITE.
1026 shutdownFlags_ |= SHUT_WRITE_PENDING;
1028 // Immediately fail all write requests
1029 failAllWrites(socketShutdownForWritesEx);
1032 case StateEnum::UNINIT:
1033 // Callers normally shouldn't call shutdownWriteNow() before the socket
1034 // even starts connecting. Nonetheless, go ahead and set
1035 // SHUT_WRITE_PENDING. Once the socket eventually connects it will
1036 // immediately shut down the write side of the socket.
1037 shutdownFlags_ |= SHUT_WRITE_PENDING;
1039 case StateEnum::FAST_OPEN:
1040 // In fast open state we haven't call connected yet, and if we shutdown
1041 // the writes, we will never try to call connect, so shut everything down
1042 shutdownFlags_ |= SHUT_WRITE;
1043 // Immediately fail all write requests
1044 failAllWrites(socketShutdownForWritesEx);
1046 case StateEnum::CLOSED:
1047 case StateEnum::ERROR:
1048 // We should never get here. SHUT_WRITE should always be set
1049 // in STATE_CLOSED and STATE_ERROR.
1050 VLOG(4) << "AsyncSocket::shutdownWriteNow() (this=" << this
1051 << ", fd=" << fd_ << ") in unexpected state " << state_
1052 << " with SHUT_WRITE not set ("
1053 << std::hex << (int) shutdownFlags_ << ")";
1058 LOG(DFATAL) << "AsyncSocket::shutdownWriteNow() (this=" << this << ", fd="
1059 << fd_ << ") called in unknown state " << state_;
1062 bool AsyncSocket::readable() const {
1066 struct pollfd fds[1];
1068 fds[0].events = POLLIN;
1070 int rc = poll(fds, 1, 0);
1074 bool AsyncSocket::isPending() const {
1075 return ioHandler_.isPending();
1078 bool AsyncSocket::hangup() const {
1080 // sanity check, no one should ask for hangup if we are not connected.
1084 #ifdef POLLRDHUP // Linux-only
1085 struct pollfd fds[1];
1087 fds[0].events = POLLRDHUP|POLLHUP;
1090 return (fds[0].revents & (POLLRDHUP|POLLHUP)) != 0;
1096 bool AsyncSocket::good() const {
1098 (state_ == StateEnum::CONNECTING || state_ == StateEnum::FAST_OPEN ||
1099 state_ == StateEnum::ESTABLISHED) &&
1100 (shutdownFlags_ == 0) && (eventBase_ != nullptr));
1103 bool AsyncSocket::error() const {
1104 return (state_ == StateEnum::ERROR);
1107 void AsyncSocket::attachEventBase(EventBase* eventBase) {
1108 VLOG(5) << "AsyncSocket::attachEventBase(this=" << this << ", fd=" << fd_
1109 << ", old evb=" << eventBase_ << ", new evb=" << eventBase
1110 << ", state=" << state_ << ", events="
1111 << std::hex << eventFlags_ << ")";
1112 assert(eventBase_ == nullptr);
1113 assert(eventBase->isInEventBaseThread());
1115 eventBase_ = eventBase;
1116 ioHandler_.attachEventBase(eventBase);
1117 writeTimeout_.attachEventBase(eventBase);
1120 void AsyncSocket::detachEventBase() {
1121 VLOG(5) << "AsyncSocket::detachEventBase(this=" << this << ", fd=" << fd_
1122 << ", old evb=" << eventBase_ << ", state=" << state_
1123 << ", events=" << std::hex << eventFlags_ << ")";
1124 assert(eventBase_ != nullptr);
1125 assert(eventBase_->isInEventBaseThread());
1127 eventBase_ = nullptr;
1128 ioHandler_.detachEventBase();
1129 writeTimeout_.detachEventBase();
1132 bool AsyncSocket::isDetachable() const {
1133 DCHECK(eventBase_ != nullptr);
1134 DCHECK(eventBase_->isInEventBaseThread());
1136 return !ioHandler_.isHandlerRegistered() && !writeTimeout_.isScheduled();
1139 void AsyncSocket::getLocalAddress(folly::SocketAddress* address) const {
1140 if (!localAddr_.isInitialized()) {
1141 localAddr_.setFromLocalAddress(fd_);
1143 *address = localAddr_;
1146 void AsyncSocket::getPeerAddress(folly::SocketAddress* address) const {
1147 if (!addr_.isInitialized()) {
1148 addr_.setFromPeerAddress(fd_);
1153 bool AsyncSocket::getTFOSucceded() const {
1154 return detail::tfo_succeeded(fd_);
1157 int AsyncSocket::setNoDelay(bool noDelay) {
1159 VLOG(4) << "AsyncSocket::setNoDelay() called on non-open socket "
1160 << this << "(state=" << state_ << ")";
1165 int value = noDelay ? 1 : 0;
1166 if (setsockopt(fd_, IPPROTO_TCP, TCP_NODELAY, &value, sizeof(value)) != 0) {
1167 int errnoCopy = errno;
1168 VLOG(2) << "failed to update TCP_NODELAY option on AsyncSocket "
1169 << this << " (fd=" << fd_ << ", state=" << state_ << "): "
1170 << strerror(errnoCopy);
1177 int AsyncSocket::setCongestionFlavor(const std::string &cname) {
1179 #ifndef TCP_CONGESTION
1180 #define TCP_CONGESTION 13
1184 VLOG(4) << "AsyncSocket::setCongestionFlavor() called on non-open "
1185 << "socket " << this << "(state=" << state_ << ")";
1190 if (setsockopt(fd_, IPPROTO_TCP, TCP_CONGESTION, cname.c_str(),
1191 cname.length() + 1) != 0) {
1192 int errnoCopy = errno;
1193 VLOG(2) << "failed to update TCP_CONGESTION option on AsyncSocket "
1194 << this << "(fd=" << fd_ << ", state=" << state_ << "): "
1195 << strerror(errnoCopy);
1202 int AsyncSocket::setQuickAck(bool quickack) {
1204 VLOG(4) << "AsyncSocket::setQuickAck() called on non-open socket "
1205 << this << "(state=" << state_ << ")";
1210 #ifdef TCP_QUICKACK // Linux-only
1211 int value = quickack ? 1 : 0;
1212 if (setsockopt(fd_, IPPROTO_TCP, TCP_QUICKACK, &value, sizeof(value)) != 0) {
1213 int errnoCopy = errno;
1214 VLOG(2) << "failed to update TCP_QUICKACK option on AsyncSocket"
1215 << this << "(fd=" << fd_ << ", state=" << state_ << "): "
1216 << strerror(errnoCopy);
1226 int AsyncSocket::setSendBufSize(size_t bufsize) {
1228 VLOG(4) << "AsyncSocket::setSendBufSize() called on non-open socket "
1229 << this << "(state=" << state_ << ")";
1233 if (setsockopt(fd_, SOL_SOCKET, SO_SNDBUF, &bufsize, sizeof(bufsize)) !=0) {
1234 int errnoCopy = errno;
1235 VLOG(2) << "failed to update SO_SNDBUF option on AsyncSocket"
1236 << this << "(fd=" << fd_ << ", state=" << state_ << "): "
1237 << strerror(errnoCopy);
1244 int AsyncSocket::setRecvBufSize(size_t bufsize) {
1246 VLOG(4) << "AsyncSocket::setRecvBufSize() called on non-open socket "
1247 << this << "(state=" << state_ << ")";
1251 if (setsockopt(fd_, SOL_SOCKET, SO_RCVBUF, &bufsize, sizeof(bufsize)) !=0) {
1252 int errnoCopy = errno;
1253 VLOG(2) << "failed to update SO_RCVBUF option on AsyncSocket"
1254 << this << "(fd=" << fd_ << ", state=" << state_ << "): "
1255 << strerror(errnoCopy);
1262 int AsyncSocket::setTCPProfile(int profd) {
1264 VLOG(4) << "AsyncSocket::setTCPProfile() called on non-open socket "
1265 << this << "(state=" << state_ << ")";
1269 if (setsockopt(fd_, SOL_SOCKET, SO_SET_NAMESPACE, &profd, sizeof(int)) !=0) {
1270 int errnoCopy = errno;
1271 VLOG(2) << "failed to set socket namespace option on AsyncSocket"
1272 << this << "(fd=" << fd_ << ", state=" << state_ << "): "
1273 << strerror(errnoCopy);
1280 void AsyncSocket::ioReady(uint16_t events) noexcept {
1281 VLOG(7) << "AsyncSocket::ioRead() this=" << this << ", fd" << fd_
1282 << ", events=" << std::hex << events << ", state=" << state_;
1283 DestructorGuard dg(this);
1284 assert(events & EventHandler::READ_WRITE);
1285 assert(eventBase_->isInEventBaseThread());
1287 uint16_t relevantEvents = events & EventHandler::READ_WRITE;
1288 if (relevantEvents == EventHandler::READ) {
1290 } else if (relevantEvents == EventHandler::WRITE) {
1292 } else if (relevantEvents == EventHandler::READ_WRITE) {
1293 EventBase* originalEventBase = eventBase_;
1294 // If both read and write events are ready, process writes first.
1297 // Return now if handleWrite() detached us from our EventBase
1298 if (eventBase_ != originalEventBase) {
1302 // Only call handleRead() if a read callback is still installed.
1303 // (It's possible that the read callback was uninstalled during
1305 if (readCallback_) {
1309 VLOG(4) << "AsyncSocket::ioRead() called with unexpected events "
1310 << std::hex << events << "(this=" << this << ")";
1315 AsyncSocket::ReadResult
1316 AsyncSocket::performRead(void** buf, size_t* buflen, size_t* /* offset */) {
1317 VLOG(5) << "AsyncSocket::performRead() this=" << this << ", buf=" << *buf
1318 << ", buflen=" << *buflen;
1322 recvFlags |= MSG_PEEK;
1325 ssize_t bytes = recv(fd_, *buf, *buflen, MSG_DONTWAIT | recvFlags);
1327 if (errno == EAGAIN || errno == EWOULDBLOCK) {
1328 // No more data to read right now.
1329 return ReadResult(READ_BLOCKING);
1331 return ReadResult(READ_ERROR);
1334 appBytesReceived_ += bytes;
1335 return ReadResult(bytes);
1339 void AsyncSocket::prepareReadBuffer(void** buf, size_t* buflen) {
1340 // no matter what, buffer should be preapared for non-ssl socket
1341 CHECK(readCallback_);
1342 readCallback_->getReadBuffer(buf, buflen);
1345 void AsyncSocket::handleRead() noexcept {
1346 VLOG(5) << "AsyncSocket::handleRead() this=" << this << ", fd=" << fd_
1347 << ", state=" << state_;
1348 assert(state_ == StateEnum::ESTABLISHED);
1349 assert((shutdownFlags_ & SHUT_READ) == 0);
1350 assert(readCallback_ != nullptr);
1351 assert(eventFlags_ & EventHandler::READ);
1354 // - a read attempt would block
1355 // - readCallback_ is uninstalled
1356 // - the number of loop iterations exceeds the optional maximum
1357 // - this AsyncSocket is moved to another EventBase
1359 // When we invoke readDataAvailable() it may uninstall the readCallback_,
1360 // which is why need to check for it here.
1362 // The last bullet point is slightly subtle. readDataAvailable() may also
1363 // detach this socket from this EventBase. However, before
1364 // readDataAvailable() returns another thread may pick it up, attach it to
1365 // a different EventBase, and install another readCallback_. We need to
1366 // exit immediately after readDataAvailable() returns if the eventBase_ has
1367 // changed. (The caller must perform some sort of locking to transfer the
1368 // AsyncSocket between threads properly. This will be sufficient to ensure
1369 // that this thread sees the updated eventBase_ variable after
1370 // readDataAvailable() returns.)
1371 uint16_t numReads = 0;
1372 EventBase* originalEventBase = eventBase_;
1373 while (readCallback_ && eventBase_ == originalEventBase) {
1374 // Get the buffer to read into.
1375 void* buf = nullptr;
1376 size_t buflen = 0, offset = 0;
1378 prepareReadBuffer(&buf, &buflen);
1379 VLOG(5) << "prepareReadBuffer() buf=" << buf << ", buflen=" << buflen;
1380 } catch (const AsyncSocketException& ex) {
1381 return failRead(__func__, ex);
1382 } catch (const std::exception& ex) {
1383 AsyncSocketException tex(AsyncSocketException::BAD_ARGS,
1384 string("ReadCallback::getReadBuffer() "
1385 "threw exception: ") +
1387 return failRead(__func__, tex);
1389 AsyncSocketException ex(AsyncSocketException::BAD_ARGS,
1390 "ReadCallback::getReadBuffer() threw "
1391 "non-exception type");
1392 return failRead(__func__, ex);
1394 if (!isBufferMovable_ && (buf == nullptr || buflen == 0)) {
1395 AsyncSocketException ex(AsyncSocketException::BAD_ARGS,
1396 "ReadCallback::getReadBuffer() returned "
1398 return failRead(__func__, ex);
1402 auto readResult = performRead(&buf, &buflen, &offset);
1403 auto bytesRead = readResult.readReturn;
1404 VLOG(4) << "this=" << this << ", AsyncSocket::handleRead() got "
1405 << bytesRead << " bytes";
1406 if (bytesRead > 0) {
1407 if (!isBufferMovable_) {
1408 readCallback_->readDataAvailable(bytesRead);
1410 CHECK(kOpenSslModeMoveBufferOwnership);
1411 VLOG(5) << "this=" << this << ", AsyncSocket::handleRead() got "
1412 << "buf=" << buf << ", " << bytesRead << "/" << buflen
1413 << ", offset=" << offset;
1414 auto readBuf = folly::IOBuf::takeOwnership(buf, buflen);
1415 readBuf->trimStart(offset);
1416 readBuf->trimEnd(buflen - offset - bytesRead);
1417 readCallback_->readBufferAvailable(std::move(readBuf));
1420 // Fall through and continue around the loop if the read
1421 // completely filled the available buffer.
1422 // Note that readCallback_ may have been uninstalled or changed inside
1423 // readDataAvailable().
1424 if (size_t(bytesRead) < buflen) {
1427 } else if (bytesRead == READ_BLOCKING) {
1428 // No more data to read right now.
1430 } else if (bytesRead == READ_ERROR) {
1431 readErr_ = READ_ERROR;
1432 if (readResult.exception) {
1433 return failRead(__func__, *readResult.exception);
1435 auto errnoCopy = errno;
1436 AsyncSocketException ex(
1437 AsyncSocketException::INTERNAL_ERROR,
1438 withAddr("recv() failed"),
1440 return failRead(__func__, ex);
1442 assert(bytesRead == READ_EOF);
1443 readErr_ = READ_EOF;
1445 shutdownFlags_ |= SHUT_READ;
1446 if (!updateEventRegistration(0, EventHandler::READ)) {
1447 // we've already been moved into STATE_ERROR
1448 assert(state_ == StateEnum::ERROR);
1449 assert(readCallback_ == nullptr);
1453 ReadCallback* callback = readCallback_;
1454 readCallback_ = nullptr;
1455 callback->readEOF();
1458 if (maxReadsPerEvent_ && (++numReads >= maxReadsPerEvent_)) {
1459 if (readCallback_ != nullptr) {
1460 // We might still have data in the socket.
1461 // (e.g. see comment in AsyncSSLSocket::checkForImmediateRead)
1462 scheduleImmediateRead();
1470 * This function attempts to write as much data as possible, until no more data
1473 * - If it sends all available data, it unregisters for write events, and stops
1474 * the writeTimeout_.
1476 * - If not all of the data can be sent immediately, it reschedules
1477 * writeTimeout_ (if a non-zero timeout is set), and ensures the handler is
1478 * registered for write events.
1480 void AsyncSocket::handleWrite() noexcept {
1481 VLOG(5) << "AsyncSocket::handleWrite() this=" << this << ", fd=" << fd_
1482 << ", state=" << state_;
1483 DestructorGuard dg(this);
1485 if (state_ == StateEnum::CONNECTING) {
1491 assert(state_ == StateEnum::ESTABLISHED);
1492 assert((shutdownFlags_ & SHUT_WRITE) == 0);
1493 assert(writeReqHead_ != nullptr);
1495 // Loop until we run out of write requests,
1496 // or until this socket is moved to another EventBase.
1497 // (See the comment in handleRead() explaining how this can happen.)
1498 EventBase* originalEventBase = eventBase_;
1499 while (writeReqHead_ != nullptr && eventBase_ == originalEventBase) {
1500 auto writeResult = writeReqHead_->performWrite();
1501 if (writeResult.writeReturn < 0) {
1502 if (writeResult.exception) {
1503 return failWrite(__func__, *writeResult.exception);
1505 auto errnoCopy = errno;
1506 AsyncSocketException ex(
1507 AsyncSocketException::INTERNAL_ERROR,
1508 withAddr("writev() failed"),
1510 return failWrite(__func__, ex);
1511 } else if (writeReqHead_->isComplete()) {
1512 // We finished this request
1513 WriteRequest* req = writeReqHead_;
1514 writeReqHead_ = req->getNext();
1516 if (writeReqHead_ == nullptr) {
1517 writeReqTail_ = nullptr;
1518 // This is the last write request.
1519 // Unregister for write events and cancel the send timer
1520 // before we invoke the callback. We have to update the state properly
1521 // before calling the callback, since it may want to detach us from
1523 if (eventFlags_ & EventHandler::WRITE) {
1524 if (!updateEventRegistration(0, EventHandler::WRITE)) {
1525 assert(state_ == StateEnum::ERROR);
1528 // Stop the send timeout
1529 writeTimeout_.cancelTimeout();
1531 assert(!writeTimeout_.isScheduled());
1533 // If SHUT_WRITE_PENDING is set, we should shutdown the socket after
1534 // we finish sending the last write request.
1536 // We have to do this before invoking writeSuccess(), since
1537 // writeSuccess() may detach us from our EventBase.
1538 if (shutdownFlags_ & SHUT_WRITE_PENDING) {
1539 assert(connectCallback_ == nullptr);
1540 shutdownFlags_ |= SHUT_WRITE;
1542 if (shutdownFlags_ & SHUT_READ) {
1543 // Reads have already been shutdown. Fully close the socket and
1544 // move to STATE_CLOSED.
1546 // Note: This code currently moves us to STATE_CLOSED even if
1547 // close() hasn't ever been called. This can occur if we have
1548 // received EOF from the peer and shutdownWrite() has been called
1549 // locally. Should we bother staying in STATE_ESTABLISHED in this
1550 // case, until close() is actually called? I can't think of a
1551 // reason why we would need to do so. No other operations besides
1552 // calling close() or destroying the socket can be performed at
1554 assert(readCallback_ == nullptr);
1555 state_ = StateEnum::CLOSED;
1557 ioHandler_.changeHandlerFD(-1);
1561 // Reads are still enabled, so we are only doing a half-shutdown
1562 shutdown(fd_, SHUT_WR);
1567 // Invoke the callback
1568 WriteCallback* callback = req->getCallback();
1571 callback->writeSuccess();
1573 // We'll continue around the loop, trying to write another request
1576 if (bufferCallback_) {
1577 bufferCallback_->onEgressBuffered();
1579 writeReqHead_->consume();
1580 // Stop after a partial write; it's highly likely that a subsequent write
1581 // attempt will just return EAGAIN.
1583 // Ensure that we are registered for write events.
1584 if ((eventFlags_ & EventHandler::WRITE) == 0) {
1585 if (!updateEventRegistration(EventHandler::WRITE, 0)) {
1586 assert(state_ == StateEnum::ERROR);
1591 // Reschedule the send timeout, since we have made some write progress.
1592 if (sendTimeout_ > 0) {
1593 if (!writeTimeout_.scheduleTimeout(sendTimeout_)) {
1594 AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
1595 withAddr("failed to reschedule write timeout"));
1596 return failWrite(__func__, ex);
1602 if (!writeReqHead_ && bufferCallback_) {
1603 bufferCallback_->onEgressBufferCleared();
1607 void AsyncSocket::checkForImmediateRead() noexcept {
1608 // We currently don't attempt to perform optimistic reads in AsyncSocket.
1609 // (However, note that some subclasses do override this method.)
1611 // Simply calling handleRead() here would be bad, as this would call
1612 // readCallback_->getReadBuffer(), forcing the callback to allocate a read
1613 // buffer even though no data may be available. This would waste lots of
1614 // memory, since the buffer will sit around unused until the socket actually
1615 // becomes readable.
1617 // Checking if the socket is readable now also seems like it would probably
1618 // be a pessimism. In most cases it probably wouldn't be readable, and we
1619 // would just waste an extra system call. Even if it is readable, waiting to
1620 // find out from libevent on the next event loop doesn't seem that bad.
1623 void AsyncSocket::handleInitialReadWrite() noexcept {
1624 // Our callers should already be holding a DestructorGuard, but grab
1625 // one here just to make sure, in case one of our calling code paths ever
1627 DestructorGuard dg(this);
1628 // If we have a readCallback_, make sure we enable read events. We
1629 // may already be registered for reads if connectSuccess() set
1630 // the read calback.
1631 if (readCallback_ && !(eventFlags_ & EventHandler::READ)) {
1632 assert(state_ == StateEnum::ESTABLISHED);
1633 assert((shutdownFlags_ & SHUT_READ) == 0);
1634 if (!updateEventRegistration(EventHandler::READ, 0)) {
1635 assert(state_ == StateEnum::ERROR);
1638 checkForImmediateRead();
1639 } else if (readCallback_ == nullptr) {
1640 // Unregister for read events.
1641 updateEventRegistration(0, EventHandler::READ);
1644 // If we have write requests pending, try to send them immediately.
1645 // Since we just finished accepting, there is a very good chance that we can
1646 // write without blocking.
1648 // However, we only process them if EventHandler::WRITE is not already set,
1649 // which means that we're already blocked on a write attempt. (This can
1650 // happen if connectSuccess() called write() before returning.)
1651 if (writeReqHead_ && !(eventFlags_ & EventHandler::WRITE)) {
1652 // Call handleWrite() to perform write processing.
1654 } else if (writeReqHead_ == nullptr) {
1655 // Unregister for write event.
1656 updateEventRegistration(0, EventHandler::WRITE);
1660 void AsyncSocket::handleConnect() noexcept {
1661 VLOG(5) << "AsyncSocket::handleConnect() this=" << this << ", fd=" << fd_
1662 << ", state=" << state_;
1663 assert(state_ == StateEnum::CONNECTING);
1664 // SHUT_WRITE can never be set while we are still connecting;
1665 // SHUT_WRITE_PENDING may be set, be we only set SHUT_WRITE once the connect
1667 assert((shutdownFlags_ & SHUT_WRITE) == 0);
1669 // In case we had a connect timeout, cancel the timeout
1670 writeTimeout_.cancelTimeout();
1671 // We don't use a persistent registration when waiting on a connect event,
1672 // so we have been automatically unregistered now. Update eventFlags_ to
1674 assert(eventFlags_ == EventHandler::WRITE);
1675 eventFlags_ = EventHandler::NONE;
1677 // Call getsockopt() to check if the connect succeeded
1679 socklen_t len = sizeof(error);
1680 int rv = getsockopt(fd_, SOL_SOCKET, SO_ERROR, &error, &len);
1682 auto errnoCopy = errno;
1683 AsyncSocketException ex(
1684 AsyncSocketException::INTERNAL_ERROR,
1685 withAddr("error calling getsockopt() after connect"),
1687 VLOG(4) << "AsyncSocket::handleConnect(this=" << this << ", fd="
1688 << fd_ << " host=" << addr_.describe()
1689 << ") exception:" << ex.what();
1690 return failConnect(__func__, ex);
1694 AsyncSocketException ex(AsyncSocketException::NOT_OPEN,
1695 "connect failed", error);
1696 VLOG(1) << "AsyncSocket::handleConnect(this=" << this << ", fd="
1697 << fd_ << " host=" << addr_.describe()
1698 << ") exception: " << ex.what();
1699 return failConnect(__func__, ex);
1702 // Move into STATE_ESTABLISHED
1703 state_ = StateEnum::ESTABLISHED;
1705 // If SHUT_WRITE_PENDING is set and we don't have any write requests to
1706 // perform, immediately shutdown the write half of the socket.
1707 if ((shutdownFlags_ & SHUT_WRITE_PENDING) && writeReqHead_ == nullptr) {
1708 // SHUT_READ shouldn't be set. If close() is called on the socket while we
1709 // are still connecting we just abort the connect rather than waiting for
1711 assert((shutdownFlags_ & SHUT_READ) == 0);
1712 shutdown(fd_, SHUT_WR);
1713 shutdownFlags_ |= SHUT_WRITE;
1716 VLOG(7) << "AsyncSocket " << this << ": fd " << fd_
1717 << "successfully connected; state=" << state_;
1719 // Remember the EventBase we are attached to, before we start invoking any
1720 // callbacks (since the callbacks may call detachEventBase()).
1721 EventBase* originalEventBase = eventBase_;
1723 invokeConnectSuccess();
1724 // Note that the connect callback may have changed our state.
1725 // (set or unset the read callback, called write(), closed the socket, etc.)
1726 // The following code needs to handle these situations correctly.
1728 // If the socket has been closed, readCallback_ and writeReqHead_ will
1729 // always be nullptr, so that will prevent us from trying to read or write.
1731 // The main thing to check for is if eventBase_ is still originalEventBase.
1732 // If not, we have been detached from this event base, so we shouldn't
1733 // perform any more operations.
1734 if (eventBase_ != originalEventBase) {
1738 handleInitialReadWrite();
1741 void AsyncSocket::timeoutExpired() noexcept {
1742 VLOG(7) << "AsyncSocket " << this << ", fd " << fd_ << ": timeout expired: "
1743 << "state=" << state_ << ", events=" << std::hex << eventFlags_;
1744 DestructorGuard dg(this);
1745 assert(eventBase_->isInEventBaseThread());
1747 if (state_ == StateEnum::CONNECTING) {
1748 // connect() timed out
1749 // Unregister for I/O events.
1750 if (connectCallback_) {
1751 AsyncSocketException ex(
1752 AsyncSocketException::TIMED_OUT, "connect timed out");
1753 failConnect(__func__, ex);
1755 // we faced a connect error without a connect callback, which could
1756 // happen due to TFO.
1757 AsyncSocketException ex(
1758 AsyncSocketException::TIMED_OUT, "write timed out during connection");
1759 failWrite(__func__, ex);
1762 // a normal write operation timed out
1763 AsyncSocketException ex(AsyncSocketException::TIMED_OUT, "write timed out");
1764 failWrite(__func__, ex);
1768 ssize_t AsyncSocket::tfoSendMsg(int fd, struct msghdr* msg, int msg_flags) {
1769 return detail::tfo_sendmsg(fd, msg, msg_flags);
1772 AsyncSocket::WriteResult
1773 AsyncSocket::sendSocketMessage(int fd, struct msghdr* msg, int msg_flags) {
1774 ssize_t totalWritten = 0;
1775 if (state_ == StateEnum::FAST_OPEN) {
1776 sockaddr_storage addr;
1777 auto len = addr_.getAddress(&addr);
1778 msg->msg_name = &addr;
1779 msg->msg_namelen = len;
1780 totalWritten = tfoSendMsg(fd_, msg, msg_flags);
1781 if (totalWritten >= 0) {
1782 tfoFinished_ = true;
1783 state_ = StateEnum::ESTABLISHED;
1784 // We schedule this asynchrously so that we don't end up
1785 // invoking initial read or write while a write is in progress.
1786 scheduleInitialReadWrite();
1787 } else if (errno == EINPROGRESS) {
1788 VLOG(4) << "TFO falling back to connecting";
1789 // A normal sendmsg doesn't return EINPROGRESS, however
1790 // TFO might fallback to connecting if there is no
1792 state_ = StateEnum::CONNECTING;
1794 scheduleConnectTimeout();
1795 registerForConnectEvents();
1796 } catch (const AsyncSocketException& ex) {
1798 WRITE_ERROR, folly::make_unique<AsyncSocketException>(ex));
1800 // Let's fake it that no bytes were written and return an errno.
1803 } else if (errno == EOPNOTSUPP) {
1804 // Try falling back to connecting.
1805 VLOG(4) << "TFO not supported";
1806 state_ = StateEnum::CONNECTING;
1808 int ret = socketConnect((const sockaddr*)&addr, len);
1810 // connect succeeded immediately
1811 // Treat this like no data was written.
1812 state_ = StateEnum::ESTABLISHED;
1813 scheduleInitialReadWrite();
1815 // If there was no exception during connections,
1816 // we would return that no bytes were written.
1819 } catch (const AsyncSocketException& ex) {
1821 WRITE_ERROR, folly::make_unique<AsyncSocketException>(ex));
1823 } else if (errno == EAGAIN) {
1824 // Normally sendmsg would indicate that the write would block.
1825 // However in the fast open case, it would indicate that sendmsg
1826 // fell back to a connect. This is a return code from connect()
1827 // instead, and is an error condition indicating no fds available.
1830 folly::make_unique<AsyncSocketException>(
1831 AsyncSocketException::UNKNOWN, "No more free local ports"));
1834 totalWritten = ::sendmsg(fd, msg, msg_flags);
1836 return WriteResult(totalWritten);
1839 AsyncSocket::WriteResult AsyncSocket::performWrite(
1843 uint32_t* countWritten,
1844 uint32_t* partialWritten) {
1845 // We use sendmsg() instead of writev() so that we can pass in MSG_NOSIGNAL
1846 // We correctly handle EPIPE errors, so we never want to receive SIGPIPE
1847 // (since it may terminate the program if the main program doesn't explicitly
1850 msg.msg_name = nullptr;
1851 msg.msg_namelen = 0;
1852 msg.msg_iov = const_cast<iovec *>(vec);
1853 msg.msg_iovlen = std::min<size_t>(count, kIovMax);
1854 msg.msg_control = nullptr;
1855 msg.msg_controllen = 0;
1858 int msg_flags = MSG_DONTWAIT;
1860 #ifdef MSG_NOSIGNAL // Linux-only
1861 msg_flags |= MSG_NOSIGNAL;
1862 if (isSet(flags, WriteFlags::CORK)) {
1863 // MSG_MORE tells the kernel we have more data to send, so wait for us to
1864 // give it the rest of the data rather than immediately sending a partial
1865 // frame, even when TCP_NODELAY is enabled.
1866 msg_flags |= MSG_MORE;
1869 if (isSet(flags, WriteFlags::EOR)) {
1870 // marks that this is the last byte of a record (response)
1871 msg_flags |= MSG_EOR;
1873 auto writeResult = sendSocketMessage(fd_, &msg, msg_flags);
1874 auto totalWritten = writeResult.writeReturn;
1875 if (totalWritten < 0) {
1876 bool tryAgain = (errno == EAGAIN);
1878 // Apple has a bug where doing a second write on a socket which we
1879 // have opened with TFO causes an ENOTCONN to be thrown. However the
1880 // socket is really connected, so treat ENOTCONN as a EAGAIN until
1881 // this bug is fixed.
1882 tryAgain |= (errno == ENOTCONN);
1884 if (!writeResult.exception && tryAgain) {
1885 // TCP buffer is full; we can't write any more data right now.
1887 *partialWritten = 0;
1888 return WriteResult(0);
1892 *partialWritten = 0;
1896 appBytesWritten_ += totalWritten;
1898 uint32_t bytesWritten;
1900 for (bytesWritten = totalWritten, n = 0; n < count; ++n) {
1901 const iovec* v = vec + n;
1902 if (v->iov_len > bytesWritten) {
1903 // Partial write finished in the middle of this iovec
1905 *partialWritten = bytesWritten;
1906 return WriteResult(totalWritten);
1909 bytesWritten -= v->iov_len;
1912 assert(bytesWritten == 0);
1914 *partialWritten = 0;
1915 return WriteResult(totalWritten);
1919 * Re-register the EventHandler after eventFlags_ has changed.
1921 * If an error occurs, fail() is called to move the socket into the error state
1922 * and call all currently installed callbacks. After an error, the
1923 * AsyncSocket is completely unregistered.
1925 * @return Returns true on succcess, or false on error.
1927 bool AsyncSocket::updateEventRegistration() {
1928 VLOG(5) << "AsyncSocket::updateEventRegistration(this=" << this
1929 << ", fd=" << fd_ << ", evb=" << eventBase_ << ", state=" << state_
1930 << ", events=" << std::hex << eventFlags_;
1931 assert(eventBase_->isInEventBaseThread());
1932 if (eventFlags_ == EventHandler::NONE) {
1933 ioHandler_.unregisterHandler();
1937 // Always register for persistent events, so we don't have to re-register
1938 // after being called back.
1939 if (!ioHandler_.registerHandler(eventFlags_ | EventHandler::PERSIST)) {
1940 eventFlags_ = EventHandler::NONE; // we're not registered after error
1941 AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
1942 withAddr("failed to update AsyncSocket event registration"));
1943 fail("updateEventRegistration", ex);
1950 bool AsyncSocket::updateEventRegistration(uint16_t enable,
1952 uint16_t oldFlags = eventFlags_;
1953 eventFlags_ |= enable;
1954 eventFlags_ &= ~disable;
1955 if (eventFlags_ == oldFlags) {
1958 return updateEventRegistration();
1962 void AsyncSocket::startFail() {
1963 // startFail() should only be called once
1964 assert(state_ != StateEnum::ERROR);
1965 assert(getDestructorGuardCount() > 0);
1966 state_ = StateEnum::ERROR;
1967 // Ensure that SHUT_READ and SHUT_WRITE are set,
1968 // so all future attempts to read or write will be rejected
1969 shutdownFlags_ |= (SHUT_READ | SHUT_WRITE);
1971 if (eventFlags_ != EventHandler::NONE) {
1972 eventFlags_ = EventHandler::NONE;
1973 ioHandler_.unregisterHandler();
1975 writeTimeout_.cancelTimeout();
1978 ioHandler_.changeHandlerFD(-1);
1983 void AsyncSocket::invokeAllErrors(const AsyncSocketException& ex) {
1984 invokeConnectErr(ex);
1987 if (readCallback_) {
1988 ReadCallback* callback = readCallback_;
1989 readCallback_ = nullptr;
1990 callback->readErr(ex);
1994 void AsyncSocket::finishFail() {
1995 assert(state_ == StateEnum::ERROR);
1996 assert(getDestructorGuardCount() > 0);
1998 AsyncSocketException ex(
1999 AsyncSocketException::INTERNAL_ERROR,
2000 withAddr("socket closing after error"));
2001 invokeAllErrors(ex);
2004 void AsyncSocket::finishFail(const AsyncSocketException& ex) {
2005 assert(state_ == StateEnum::ERROR);
2006 assert(getDestructorGuardCount() > 0);
2007 invokeAllErrors(ex);
2010 void AsyncSocket::fail(const char* fn, const AsyncSocketException& ex) {
2011 VLOG(4) << "AsyncSocket(this=" << this << ", fd=" << fd_ << ", state="
2012 << state_ << " host=" << addr_.describe()
2013 << "): failed in " << fn << "(): "
2019 void AsyncSocket::failConnect(const char* fn, const AsyncSocketException& ex) {
2020 VLOG(5) << "AsyncSocket(this=" << this << ", fd=" << fd_ << ", state="
2021 << state_ << " host=" << addr_.describe()
2022 << "): failed while connecting in " << fn << "(): "
2026 invokeConnectErr(ex);
2030 void AsyncSocket::failRead(const char* fn, const AsyncSocketException& ex) {
2031 VLOG(5) << "AsyncSocket(this=" << this << ", fd=" << fd_ << ", state="
2032 << state_ << " host=" << addr_.describe()
2033 << "): failed while reading in " << fn << "(): "
2037 if (readCallback_ != nullptr) {
2038 ReadCallback* callback = readCallback_;
2039 readCallback_ = nullptr;
2040 callback->readErr(ex);
2046 void AsyncSocket::failWrite(const char* fn, const AsyncSocketException& ex) {
2047 VLOG(5) << "AsyncSocket(this=" << this << ", fd=" << fd_ << ", state="
2048 << state_ << " host=" << addr_.describe()
2049 << "): failed while writing in " << fn << "(): "
2053 // Only invoke the first write callback, since the error occurred while
2054 // writing this request. Let any other pending write callbacks be invoked in
2056 if (writeReqHead_ != nullptr) {
2057 WriteRequest* req = writeReqHead_;
2058 writeReqHead_ = req->getNext();
2059 WriteCallback* callback = req->getCallback();
2060 uint32_t bytesWritten = req->getTotalBytesWritten();
2063 callback->writeErr(bytesWritten, ex);
2070 void AsyncSocket::failWrite(const char* fn, WriteCallback* callback,
2071 size_t bytesWritten,
2072 const AsyncSocketException& ex) {
2073 // This version of failWrite() is used when the failure occurs before
2074 // we've added the callback to writeReqHead_.
2075 VLOG(4) << "AsyncSocket(this=" << this << ", fd=" << fd_ << ", state="
2076 << state_ << " host=" << addr_.describe()
2077 <<"): failed while writing in " << fn << "(): "
2081 if (callback != nullptr) {
2082 callback->writeErr(bytesWritten, ex);
2088 void AsyncSocket::failAllWrites(const AsyncSocketException& ex) {
2089 // Invoke writeError() on all write callbacks.
2090 // This is used when writes are forcibly shutdown with write requests
2091 // pending, or when an error occurs with writes pending.
2092 while (writeReqHead_ != nullptr) {
2093 WriteRequest* req = writeReqHead_;
2094 writeReqHead_ = req->getNext();
2095 WriteCallback* callback = req->getCallback();
2097 callback->writeErr(req->getTotalBytesWritten(), ex);
2103 void AsyncSocket::invalidState(ConnectCallback* callback) {
2104 VLOG(5) << "AsyncSocket(this=" << this << ", fd=" << fd_
2105 << "): connect() called in invalid state " << state_;
2108 * The invalidState() methods don't use the normal failure mechanisms,
2109 * since we don't know what state we are in. We don't want to call
2110 * startFail()/finishFail() recursively if we are already in the middle of
2114 AsyncSocketException ex(AsyncSocketException::ALREADY_OPEN,
2115 "connect() called with socket in invalid state");
2116 connectEndTime_ = std::chrono::steady_clock::now();
2117 if (state_ == StateEnum::CLOSED || state_ == StateEnum::ERROR) {
2119 callback->connectErr(ex);
2122 // We can't use failConnect() here since connectCallback_
2123 // may already be set to another callback. Invoke this ConnectCallback
2124 // here; any other connectCallback_ will be invoked in finishFail()
2127 callback->connectErr(ex);
2133 void AsyncSocket::invokeConnectErr(const AsyncSocketException& ex) {
2134 connectEndTime_ = std::chrono::steady_clock::now();
2135 if (connectCallback_) {
2136 ConnectCallback* callback = connectCallback_;
2137 connectCallback_ = nullptr;
2138 callback->connectErr(ex);
2142 void AsyncSocket::invokeConnectSuccess() {
2143 connectEndTime_ = std::chrono::steady_clock::now();
2144 if (connectCallback_) {
2145 ConnectCallback* callback = connectCallback_;
2146 connectCallback_ = nullptr;
2147 callback->connectSuccess();
2151 void AsyncSocket::invalidState(ReadCallback* callback) {
2152 VLOG(4) << "AsyncSocket(this=" << this << ", fd=" << fd_
2153 << "): setReadCallback(" << callback
2154 << ") called in invalid state " << state_;
2156 AsyncSocketException ex(AsyncSocketException::NOT_OPEN,
2157 "setReadCallback() called with socket in "
2159 if (state_ == StateEnum::CLOSED || state_ == StateEnum::ERROR) {
2161 callback->readErr(ex);
2166 callback->readErr(ex);
2172 void AsyncSocket::invalidState(WriteCallback* callback) {
2173 VLOG(4) << "AsyncSocket(this=" << this << ", fd=" << fd_
2174 << "): write() called in invalid state " << state_;
2176 AsyncSocketException ex(AsyncSocketException::NOT_OPEN,
2177 withAddr("write() called with socket in invalid state"));
2178 if (state_ == StateEnum::CLOSED || state_ == StateEnum::ERROR) {
2180 callback->writeErr(0, ex);
2185 callback->writeErr(0, ex);
2191 void AsyncSocket::doClose() {
2192 if (fd_ == -1) return;
2193 if (shutdownSocketSet_) {
2194 shutdownSocketSet_->close(fd_);
2201 std::ostream& operator << (std::ostream& os,
2202 const AsyncSocket::StateEnum& state) {
2203 os << static_cast<int>(state);
2207 std::string AsyncSocket::withAddr(const std::string& s) {
2208 // Don't use addr_ directly because it may not be initialized
2209 // e.g. if constructed from fd
2210 folly::SocketAddress peer, local;
2212 getPeerAddress(&peer);
2213 getLocalAddress(&local);
2214 } catch (const std::exception&) {
2219 return s + " (peer=" + peer.describe() + ", local=" + local.describe() + ")";
2222 void AsyncSocket::setBufferCallback(BufferCallback* cb) {
2223 bufferCallback_ = cb;