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 auto timeout = connectTimeout_.count();
494 // Start a timer in case the connection takes too long.
495 if (!writeTimeout_.scheduleTimeout(uint32_t(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 ssize_t 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);
728 auto writeResult = performWrite(
729 vec, uint32_t(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(
773 uint32_t(count - countWritten),
775 uint32_t(bytesWritten),
778 } catch (const std::exception& ex) {
779 // we mainly expect to catch std::bad_alloc here
780 AsyncSocketException tex(AsyncSocketException::INTERNAL_ERROR,
781 withAddr(string("failed to append new WriteRequest: ") + ex.what()));
782 return failWrite(__func__, callback, size_t(bytesWritten), tex);
785 if (writeReqTail_ == nullptr) {
786 assert(writeReqHead_ == nullptr);
787 writeReqHead_ = writeReqTail_ = req;
789 writeReqTail_->append(req);
793 // Register for write events if are established and not currently
794 // waiting on write events
796 assert(state_ == StateEnum::ESTABLISHED);
797 assert((eventFlags_ & EventHandler::WRITE) == 0);
798 if (!updateEventRegistration(EventHandler::WRITE, 0)) {
799 assert(state_ == StateEnum::ERROR);
802 if (sendTimeout_ > 0) {
803 // Schedule a timeout to fire if the write takes too long.
804 if (!writeTimeout_.scheduleTimeout(sendTimeout_)) {
805 AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
806 withAddr("failed to schedule send timeout"));
807 return failWrite(__func__, ex);
813 void AsyncSocket::writeRequest(WriteRequest* req) {
814 if (writeReqTail_ == nullptr) {
815 assert(writeReqHead_ == nullptr);
816 writeReqHead_ = writeReqTail_ = req;
819 writeReqTail_->append(req);
824 void AsyncSocket::close() {
825 VLOG(5) << "AsyncSocket::close(): this=" << this << ", fd_=" << fd_
826 << ", state=" << state_ << ", shutdownFlags="
827 << std::hex << (int) shutdownFlags_;
829 // close() is only different from closeNow() when there are pending writes
830 // that need to drain before we can close. In all other cases, just call
833 // Note that writeReqHead_ can be non-nullptr even in STATE_CLOSED or
834 // STATE_ERROR if close() is invoked while a previous closeNow() or failure
835 // is still running. (e.g., If there are multiple pending writes, and we
836 // call writeError() on the first one, it may call close(). In this case we
837 // will already be in STATE_CLOSED or STATE_ERROR, but the remaining pending
838 // writes will still be in the queue.)
840 // We only need to drain pending writes if we are still in STATE_CONNECTING
841 // or STATE_ESTABLISHED
842 if ((writeReqHead_ == nullptr) ||
843 !(state_ == StateEnum::CONNECTING ||
844 state_ == StateEnum::ESTABLISHED)) {
849 // Declare a DestructorGuard to ensure that the AsyncSocket cannot be
850 // destroyed until close() returns.
851 DestructorGuard dg(this);
852 assert(eventBase_->isInEventBaseThread());
854 // Since there are write requests pending, we have to set the
855 // SHUT_WRITE_PENDING flag, and wait to perform the real close until the
856 // connect finishes and we finish writing these requests.
858 // Set SHUT_READ to indicate that reads are shut down, and set the
859 // SHUT_WRITE_PENDING flag to mark that we want to shutdown once the
860 // pending writes complete.
861 shutdownFlags_ |= (SHUT_READ | SHUT_WRITE_PENDING);
863 // If a read callback is set, invoke readEOF() immediately to inform it that
864 // the socket has been closed and no more data can be read.
866 // Disable reads if they are enabled
867 if (!updateEventRegistration(0, EventHandler::READ)) {
868 // We're now in the error state; callbacks have been cleaned up
869 assert(state_ == StateEnum::ERROR);
870 assert(readCallback_ == nullptr);
872 ReadCallback* callback = readCallback_;
873 readCallback_ = nullptr;
879 void AsyncSocket::closeNow() {
880 VLOG(5) << "AsyncSocket::closeNow(): this=" << this << ", fd_=" << fd_
881 << ", state=" << state_ << ", shutdownFlags="
882 << std::hex << (int) shutdownFlags_;
883 DestructorGuard dg(this);
884 assert(eventBase_ == nullptr || eventBase_->isInEventBaseThread());
887 case StateEnum::ESTABLISHED:
888 case StateEnum::CONNECTING:
889 case StateEnum::FAST_OPEN: {
890 shutdownFlags_ |= (SHUT_READ | SHUT_WRITE);
891 state_ = StateEnum::CLOSED;
893 // If the write timeout was set, cancel it.
894 writeTimeout_.cancelTimeout();
896 // If we are registered for I/O events, unregister.
897 if (eventFlags_ != EventHandler::NONE) {
898 eventFlags_ = EventHandler::NONE;
899 if (!updateEventRegistration()) {
900 // We will have been moved into the error state.
901 assert(state_ == StateEnum::ERROR);
906 if (immediateReadHandler_.isLoopCallbackScheduled()) {
907 immediateReadHandler_.cancelLoopCallback();
911 ioHandler_.changeHandlerFD(-1);
915 invokeConnectErr(socketClosedLocallyEx);
917 failAllWrites(socketClosedLocallyEx);
920 ReadCallback* callback = readCallback_;
921 readCallback_ = nullptr;
926 case StateEnum::CLOSED:
927 // Do nothing. It's possible that we are being called recursively
928 // from inside a callback that we invoked inside another call to close()
929 // that is still running.
931 case StateEnum::ERROR:
932 // Do nothing. The error handling code has performed (or is performing)
935 case StateEnum::UNINIT:
936 assert(eventFlags_ == EventHandler::NONE);
937 assert(connectCallback_ == nullptr);
938 assert(readCallback_ == nullptr);
939 assert(writeReqHead_ == nullptr);
940 shutdownFlags_ |= (SHUT_READ | SHUT_WRITE);
941 state_ = StateEnum::CLOSED;
945 LOG(DFATAL) << "AsyncSocket::closeNow() (this=" << this << ", fd=" << fd_
946 << ") called in unknown state " << state_;
949 void AsyncSocket::closeWithReset() {
950 // Enable SO_LINGER, with the linger timeout set to 0.
951 // This will trigger a TCP reset when we close the socket.
953 struct linger optLinger = {1, 0};
954 if (setSockOpt(SOL_SOCKET, SO_LINGER, &optLinger) != 0) {
955 VLOG(2) << "AsyncSocket::closeWithReset(): error setting SO_LINGER "
956 << "on " << fd_ << ": errno=" << errno;
960 // Then let closeNow() take care of the rest
964 void AsyncSocket::shutdownWrite() {
965 VLOG(5) << "AsyncSocket::shutdownWrite(): this=" << this << ", fd=" << fd_
966 << ", state=" << state_ << ", shutdownFlags="
967 << std::hex << (int) shutdownFlags_;
969 // If there are no pending writes, shutdownWrite() is identical to
970 // shutdownWriteNow().
971 if (writeReqHead_ == nullptr) {
976 assert(eventBase_->isInEventBaseThread());
978 // There are pending writes. Set SHUT_WRITE_PENDING so that the actual
979 // shutdown will be performed once all writes complete.
980 shutdownFlags_ |= SHUT_WRITE_PENDING;
983 void AsyncSocket::shutdownWriteNow() {
984 VLOG(5) << "AsyncSocket::shutdownWriteNow(): this=" << this
985 << ", fd=" << fd_ << ", state=" << state_
986 << ", shutdownFlags=" << std::hex << (int) shutdownFlags_;
988 if (shutdownFlags_ & SHUT_WRITE) {
989 // Writes are already shutdown; nothing else to do.
993 // If SHUT_READ is already set, just call closeNow() to completely
994 // close the socket. This can happen if close() was called with writes
995 // pending, and then shutdownWriteNow() is called before all pending writes
997 if (shutdownFlags_ & SHUT_READ) {
1002 DestructorGuard dg(this);
1003 assert(eventBase_ == nullptr || eventBase_->isInEventBaseThread());
1005 switch (static_cast<StateEnum>(state_)) {
1006 case StateEnum::ESTABLISHED:
1008 shutdownFlags_ |= SHUT_WRITE;
1010 // If the write timeout was set, cancel it.
1011 writeTimeout_.cancelTimeout();
1013 // If we are registered for write events, unregister.
1014 if (!updateEventRegistration(0, EventHandler::WRITE)) {
1015 // We will have been moved into the error state.
1016 assert(state_ == StateEnum::ERROR);
1020 // Shutdown writes on the file descriptor
1021 shutdown(fd_, SHUT_WR);
1023 // Immediately fail all write requests
1024 failAllWrites(socketShutdownForWritesEx);
1027 case StateEnum::CONNECTING:
1029 // Set the SHUT_WRITE_PENDING flag.
1030 // When the connection completes, it will check this flag,
1031 // shutdown the write half of the socket, and then set SHUT_WRITE.
1032 shutdownFlags_ |= SHUT_WRITE_PENDING;
1034 // Immediately fail all write requests
1035 failAllWrites(socketShutdownForWritesEx);
1038 case StateEnum::UNINIT:
1039 // Callers normally shouldn't call shutdownWriteNow() before the socket
1040 // even starts connecting. Nonetheless, go ahead and set
1041 // SHUT_WRITE_PENDING. Once the socket eventually connects it will
1042 // immediately shut down the write side of the socket.
1043 shutdownFlags_ |= SHUT_WRITE_PENDING;
1045 case StateEnum::FAST_OPEN:
1046 // In fast open state we haven't call connected yet, and if we shutdown
1047 // the writes, we will never try to call connect, so shut everything down
1048 shutdownFlags_ |= SHUT_WRITE;
1049 // Immediately fail all write requests
1050 failAllWrites(socketShutdownForWritesEx);
1052 case StateEnum::CLOSED:
1053 case StateEnum::ERROR:
1054 // We should never get here. SHUT_WRITE should always be set
1055 // in STATE_CLOSED and STATE_ERROR.
1056 VLOG(4) << "AsyncSocket::shutdownWriteNow() (this=" << this
1057 << ", fd=" << fd_ << ") in unexpected state " << state_
1058 << " with SHUT_WRITE not set ("
1059 << std::hex << (int) shutdownFlags_ << ")";
1064 LOG(DFATAL) << "AsyncSocket::shutdownWriteNow() (this=" << this << ", fd="
1065 << fd_ << ") called in unknown state " << state_;
1068 bool AsyncSocket::readable() const {
1072 struct pollfd fds[1];
1074 fds[0].events = POLLIN;
1076 int rc = poll(fds, 1, 0);
1080 bool AsyncSocket::isPending() const {
1081 return ioHandler_.isPending();
1084 bool AsyncSocket::hangup() const {
1086 // sanity check, no one should ask for hangup if we are not connected.
1090 #ifdef POLLRDHUP // Linux-only
1091 struct pollfd fds[1];
1093 fds[0].events = POLLRDHUP|POLLHUP;
1096 return (fds[0].revents & (POLLRDHUP|POLLHUP)) != 0;
1102 bool AsyncSocket::good() const {
1104 (state_ == StateEnum::CONNECTING || state_ == StateEnum::FAST_OPEN ||
1105 state_ == StateEnum::ESTABLISHED) &&
1106 (shutdownFlags_ == 0) && (eventBase_ != nullptr));
1109 bool AsyncSocket::error() const {
1110 return (state_ == StateEnum::ERROR);
1113 void AsyncSocket::attachEventBase(EventBase* eventBase) {
1114 VLOG(5) << "AsyncSocket::attachEventBase(this=" << this << ", fd=" << fd_
1115 << ", old evb=" << eventBase_ << ", new evb=" << eventBase
1116 << ", state=" << state_ << ", events="
1117 << std::hex << eventFlags_ << ")";
1118 assert(eventBase_ == nullptr);
1119 assert(eventBase->isInEventBaseThread());
1121 eventBase_ = eventBase;
1122 ioHandler_.attachEventBase(eventBase);
1123 writeTimeout_.attachEventBase(eventBase);
1125 evbChangeCb_->evbAttached(this);
1129 void AsyncSocket::detachEventBase() {
1130 VLOG(5) << "AsyncSocket::detachEventBase(this=" << this << ", fd=" << fd_
1131 << ", old evb=" << eventBase_ << ", state=" << state_
1132 << ", events=" << std::hex << eventFlags_ << ")";
1133 assert(eventBase_ != nullptr);
1134 assert(eventBase_->isInEventBaseThread());
1136 eventBase_ = nullptr;
1137 ioHandler_.detachEventBase();
1138 writeTimeout_.detachEventBase();
1140 evbChangeCb_->evbDetached(this);
1144 bool AsyncSocket::isDetachable() const {
1145 DCHECK(eventBase_ != nullptr);
1146 DCHECK(eventBase_->isInEventBaseThread());
1148 return !ioHandler_.isHandlerRegistered() && !writeTimeout_.isScheduled();
1151 void AsyncSocket::getLocalAddress(folly::SocketAddress* address) const {
1152 if (!localAddr_.isInitialized()) {
1153 localAddr_.setFromLocalAddress(fd_);
1155 *address = localAddr_;
1158 void AsyncSocket::getPeerAddress(folly::SocketAddress* address) const {
1159 if (!addr_.isInitialized()) {
1160 addr_.setFromPeerAddress(fd_);
1165 bool AsyncSocket::getTFOSucceded() const {
1166 return detail::tfo_succeeded(fd_);
1169 int AsyncSocket::setNoDelay(bool noDelay) {
1171 VLOG(4) << "AsyncSocket::setNoDelay() called on non-open socket "
1172 << this << "(state=" << state_ << ")";
1177 int value = noDelay ? 1 : 0;
1178 if (setsockopt(fd_, IPPROTO_TCP, TCP_NODELAY, &value, sizeof(value)) != 0) {
1179 int errnoCopy = errno;
1180 VLOG(2) << "failed to update TCP_NODELAY option on AsyncSocket "
1181 << this << " (fd=" << fd_ << ", state=" << state_ << "): "
1182 << strerror(errnoCopy);
1189 int AsyncSocket::setCongestionFlavor(const std::string &cname) {
1191 #ifndef TCP_CONGESTION
1192 #define TCP_CONGESTION 13
1196 VLOG(4) << "AsyncSocket::setCongestionFlavor() called on non-open "
1197 << "socket " << this << "(state=" << state_ << ")";
1207 socklen_t(cname.length() + 1)) != 0) {
1208 int errnoCopy = errno;
1209 VLOG(2) << "failed to update TCP_CONGESTION option on AsyncSocket "
1210 << this << "(fd=" << fd_ << ", state=" << state_ << "): "
1211 << strerror(errnoCopy);
1218 int AsyncSocket::setQuickAck(bool quickack) {
1220 VLOG(4) << "AsyncSocket::setQuickAck() called on non-open socket "
1221 << this << "(state=" << state_ << ")";
1226 #ifdef TCP_QUICKACK // Linux-only
1227 int value = quickack ? 1 : 0;
1228 if (setsockopt(fd_, IPPROTO_TCP, TCP_QUICKACK, &value, sizeof(value)) != 0) {
1229 int errnoCopy = errno;
1230 VLOG(2) << "failed to update TCP_QUICKACK option on AsyncSocket"
1231 << this << "(fd=" << fd_ << ", state=" << state_ << "): "
1232 << strerror(errnoCopy);
1242 int AsyncSocket::setSendBufSize(size_t bufsize) {
1244 VLOG(4) << "AsyncSocket::setSendBufSize() called on non-open socket "
1245 << this << "(state=" << state_ << ")";
1249 if (setsockopt(fd_, SOL_SOCKET, SO_SNDBUF, &bufsize, sizeof(bufsize)) !=0) {
1250 int errnoCopy = errno;
1251 VLOG(2) << "failed to update SO_SNDBUF option on AsyncSocket"
1252 << this << "(fd=" << fd_ << ", state=" << state_ << "): "
1253 << strerror(errnoCopy);
1260 int AsyncSocket::setRecvBufSize(size_t bufsize) {
1262 VLOG(4) << "AsyncSocket::setRecvBufSize() called on non-open socket "
1263 << this << "(state=" << state_ << ")";
1267 if (setsockopt(fd_, SOL_SOCKET, SO_RCVBUF, &bufsize, sizeof(bufsize)) !=0) {
1268 int errnoCopy = errno;
1269 VLOG(2) << "failed to update SO_RCVBUF option on AsyncSocket"
1270 << this << "(fd=" << fd_ << ", state=" << state_ << "): "
1271 << strerror(errnoCopy);
1278 int AsyncSocket::setTCPProfile(int profd) {
1280 VLOG(4) << "AsyncSocket::setTCPProfile() called on non-open socket "
1281 << this << "(state=" << state_ << ")";
1285 if (setsockopt(fd_, SOL_SOCKET, SO_SET_NAMESPACE, &profd, sizeof(int)) !=0) {
1286 int errnoCopy = errno;
1287 VLOG(2) << "failed to set socket namespace option on AsyncSocket"
1288 << this << "(fd=" << fd_ << ", state=" << state_ << "): "
1289 << strerror(errnoCopy);
1296 void AsyncSocket::ioReady(uint16_t events) noexcept {
1297 VLOG(7) << "AsyncSocket::ioRead() this=" << this << ", fd" << fd_
1298 << ", events=" << std::hex << events << ", state=" << state_;
1299 DestructorGuard dg(this);
1300 assert(events & EventHandler::READ_WRITE);
1301 assert(eventBase_->isInEventBaseThread());
1303 uint16_t relevantEvents = events & EventHandler::READ_WRITE;
1304 if (relevantEvents == EventHandler::READ) {
1306 } else if (relevantEvents == EventHandler::WRITE) {
1308 } else if (relevantEvents == EventHandler::READ_WRITE) {
1309 EventBase* originalEventBase = eventBase_;
1310 // If both read and write events are ready, process writes first.
1313 // Return now if handleWrite() detached us from our EventBase
1314 if (eventBase_ != originalEventBase) {
1318 // Only call handleRead() if a read callback is still installed.
1319 // (It's possible that the read callback was uninstalled during
1321 if (readCallback_) {
1325 VLOG(4) << "AsyncSocket::ioRead() called with unexpected events "
1326 << std::hex << events << "(this=" << this << ")";
1331 AsyncSocket::ReadResult
1332 AsyncSocket::performRead(void** buf, size_t* buflen, size_t* /* offset */) {
1333 VLOG(5) << "AsyncSocket::performRead() this=" << this << ", buf=" << *buf
1334 << ", buflen=" << *buflen;
1338 recvFlags |= MSG_PEEK;
1341 ssize_t bytes = recv(fd_, *buf, *buflen, MSG_DONTWAIT | recvFlags);
1343 if (errno == EAGAIN || errno == EWOULDBLOCK) {
1344 // No more data to read right now.
1345 return ReadResult(READ_BLOCKING);
1347 return ReadResult(READ_ERROR);
1350 appBytesReceived_ += bytes;
1351 return ReadResult(bytes);
1355 void AsyncSocket::prepareReadBuffer(void** buf, size_t* buflen) {
1356 // no matter what, buffer should be preapared for non-ssl socket
1357 CHECK(readCallback_);
1358 readCallback_->getReadBuffer(buf, buflen);
1361 void AsyncSocket::handleRead() noexcept {
1362 VLOG(5) << "AsyncSocket::handleRead() this=" << this << ", fd=" << fd_
1363 << ", state=" << state_;
1364 assert(state_ == StateEnum::ESTABLISHED);
1365 assert((shutdownFlags_ & SHUT_READ) == 0);
1366 assert(readCallback_ != nullptr);
1367 assert(eventFlags_ & EventHandler::READ);
1370 // - a read attempt would block
1371 // - readCallback_ is uninstalled
1372 // - the number of loop iterations exceeds the optional maximum
1373 // - this AsyncSocket is moved to another EventBase
1375 // When we invoke readDataAvailable() it may uninstall the readCallback_,
1376 // which is why need to check for it here.
1378 // The last bullet point is slightly subtle. readDataAvailable() may also
1379 // detach this socket from this EventBase. However, before
1380 // readDataAvailable() returns another thread may pick it up, attach it to
1381 // a different EventBase, and install another readCallback_. We need to
1382 // exit immediately after readDataAvailable() returns if the eventBase_ has
1383 // changed. (The caller must perform some sort of locking to transfer the
1384 // AsyncSocket between threads properly. This will be sufficient to ensure
1385 // that this thread sees the updated eventBase_ variable after
1386 // readDataAvailable() returns.)
1387 uint16_t numReads = 0;
1388 EventBase* originalEventBase = eventBase_;
1389 while (readCallback_ && eventBase_ == originalEventBase) {
1390 // Get the buffer to read into.
1391 void* buf = nullptr;
1392 size_t buflen = 0, offset = 0;
1394 prepareReadBuffer(&buf, &buflen);
1395 VLOG(5) << "prepareReadBuffer() buf=" << buf << ", buflen=" << buflen;
1396 } catch (const AsyncSocketException& ex) {
1397 return failRead(__func__, ex);
1398 } catch (const std::exception& ex) {
1399 AsyncSocketException tex(AsyncSocketException::BAD_ARGS,
1400 string("ReadCallback::getReadBuffer() "
1401 "threw exception: ") +
1403 return failRead(__func__, tex);
1405 AsyncSocketException ex(AsyncSocketException::BAD_ARGS,
1406 "ReadCallback::getReadBuffer() threw "
1407 "non-exception type");
1408 return failRead(__func__, ex);
1410 if (!isBufferMovable_ && (buf == nullptr || buflen == 0)) {
1411 AsyncSocketException ex(AsyncSocketException::BAD_ARGS,
1412 "ReadCallback::getReadBuffer() returned "
1414 return failRead(__func__, ex);
1418 auto readResult = performRead(&buf, &buflen, &offset);
1419 auto bytesRead = readResult.readReturn;
1420 VLOG(4) << "this=" << this << ", AsyncSocket::handleRead() got "
1421 << bytesRead << " bytes";
1422 if (bytesRead > 0) {
1423 if (!isBufferMovable_) {
1424 readCallback_->readDataAvailable(bytesRead);
1426 CHECK(kOpenSslModeMoveBufferOwnership);
1427 VLOG(5) << "this=" << this << ", AsyncSocket::handleRead() got "
1428 << "buf=" << buf << ", " << bytesRead << "/" << buflen
1429 << ", offset=" << offset;
1430 auto readBuf = folly::IOBuf::takeOwnership(buf, buflen);
1431 readBuf->trimStart(offset);
1432 readBuf->trimEnd(buflen - offset - bytesRead);
1433 readCallback_->readBufferAvailable(std::move(readBuf));
1436 // Fall through and continue around the loop if the read
1437 // completely filled the available buffer.
1438 // Note that readCallback_ may have been uninstalled or changed inside
1439 // readDataAvailable().
1440 if (size_t(bytesRead) < buflen) {
1443 } else if (bytesRead == READ_BLOCKING) {
1444 // No more data to read right now.
1446 } else if (bytesRead == READ_ERROR) {
1447 readErr_ = READ_ERROR;
1448 if (readResult.exception) {
1449 return failRead(__func__, *readResult.exception);
1451 auto errnoCopy = errno;
1452 AsyncSocketException ex(
1453 AsyncSocketException::INTERNAL_ERROR,
1454 withAddr("recv() failed"),
1456 return failRead(__func__, ex);
1458 assert(bytesRead == READ_EOF);
1459 readErr_ = READ_EOF;
1461 shutdownFlags_ |= SHUT_READ;
1462 if (!updateEventRegistration(0, EventHandler::READ)) {
1463 // we've already been moved into STATE_ERROR
1464 assert(state_ == StateEnum::ERROR);
1465 assert(readCallback_ == nullptr);
1469 ReadCallback* callback = readCallback_;
1470 readCallback_ = nullptr;
1471 callback->readEOF();
1474 if (maxReadsPerEvent_ && (++numReads >= maxReadsPerEvent_)) {
1475 if (readCallback_ != nullptr) {
1476 // We might still have data in the socket.
1477 // (e.g. see comment in AsyncSSLSocket::checkForImmediateRead)
1478 scheduleImmediateRead();
1486 * This function attempts to write as much data as possible, until no more data
1489 * - If it sends all available data, it unregisters for write events, and stops
1490 * the writeTimeout_.
1492 * - If not all of the data can be sent immediately, it reschedules
1493 * writeTimeout_ (if a non-zero timeout is set), and ensures the handler is
1494 * registered for write events.
1496 void AsyncSocket::handleWrite() noexcept {
1497 VLOG(5) << "AsyncSocket::handleWrite() this=" << this << ", fd=" << fd_
1498 << ", state=" << state_;
1499 DestructorGuard dg(this);
1501 if (state_ == StateEnum::CONNECTING) {
1507 assert(state_ == StateEnum::ESTABLISHED);
1508 assert((shutdownFlags_ & SHUT_WRITE) == 0);
1509 assert(writeReqHead_ != nullptr);
1511 // Loop until we run out of write requests,
1512 // or until this socket is moved to another EventBase.
1513 // (See the comment in handleRead() explaining how this can happen.)
1514 EventBase* originalEventBase = eventBase_;
1515 while (writeReqHead_ != nullptr && eventBase_ == originalEventBase) {
1516 auto writeResult = writeReqHead_->performWrite();
1517 if (writeResult.writeReturn < 0) {
1518 if (writeResult.exception) {
1519 return failWrite(__func__, *writeResult.exception);
1521 auto errnoCopy = errno;
1522 AsyncSocketException ex(
1523 AsyncSocketException::INTERNAL_ERROR,
1524 withAddr("writev() failed"),
1526 return failWrite(__func__, ex);
1527 } else if (writeReqHead_->isComplete()) {
1528 // We finished this request
1529 WriteRequest* req = writeReqHead_;
1530 writeReqHead_ = req->getNext();
1532 if (writeReqHead_ == nullptr) {
1533 writeReqTail_ = nullptr;
1534 // This is the last write request.
1535 // Unregister for write events and cancel the send timer
1536 // before we invoke the callback. We have to update the state properly
1537 // before calling the callback, since it may want to detach us from
1539 if (eventFlags_ & EventHandler::WRITE) {
1540 if (!updateEventRegistration(0, EventHandler::WRITE)) {
1541 assert(state_ == StateEnum::ERROR);
1544 // Stop the send timeout
1545 writeTimeout_.cancelTimeout();
1547 assert(!writeTimeout_.isScheduled());
1549 // If SHUT_WRITE_PENDING is set, we should shutdown the socket after
1550 // we finish sending the last write request.
1552 // We have to do this before invoking writeSuccess(), since
1553 // writeSuccess() may detach us from our EventBase.
1554 if (shutdownFlags_ & SHUT_WRITE_PENDING) {
1555 assert(connectCallback_ == nullptr);
1556 shutdownFlags_ |= SHUT_WRITE;
1558 if (shutdownFlags_ & SHUT_READ) {
1559 // Reads have already been shutdown. Fully close the socket and
1560 // move to STATE_CLOSED.
1562 // Note: This code currently moves us to STATE_CLOSED even if
1563 // close() hasn't ever been called. This can occur if we have
1564 // received EOF from the peer and shutdownWrite() has been called
1565 // locally. Should we bother staying in STATE_ESTABLISHED in this
1566 // case, until close() is actually called? I can't think of a
1567 // reason why we would need to do so. No other operations besides
1568 // calling close() or destroying the socket can be performed at
1570 assert(readCallback_ == nullptr);
1571 state_ = StateEnum::CLOSED;
1573 ioHandler_.changeHandlerFD(-1);
1577 // Reads are still enabled, so we are only doing a half-shutdown
1578 shutdown(fd_, SHUT_WR);
1583 // Invoke the callback
1584 WriteCallback* callback = req->getCallback();
1587 callback->writeSuccess();
1589 // We'll continue around the loop, trying to write another request
1592 if (bufferCallback_) {
1593 bufferCallback_->onEgressBuffered();
1595 writeReqHead_->consume();
1596 // Stop after a partial write; it's highly likely that a subsequent write
1597 // attempt will just return EAGAIN.
1599 // Ensure that we are registered for write events.
1600 if ((eventFlags_ & EventHandler::WRITE) == 0) {
1601 if (!updateEventRegistration(EventHandler::WRITE, 0)) {
1602 assert(state_ == StateEnum::ERROR);
1607 // Reschedule the send timeout, since we have made some write progress.
1608 if (sendTimeout_ > 0) {
1609 if (!writeTimeout_.scheduleTimeout(sendTimeout_)) {
1610 AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
1611 withAddr("failed to reschedule write timeout"));
1612 return failWrite(__func__, ex);
1618 if (!writeReqHead_ && bufferCallback_) {
1619 bufferCallback_->onEgressBufferCleared();
1623 void AsyncSocket::checkForImmediateRead() noexcept {
1624 // We currently don't attempt to perform optimistic reads in AsyncSocket.
1625 // (However, note that some subclasses do override this method.)
1627 // Simply calling handleRead() here would be bad, as this would call
1628 // readCallback_->getReadBuffer(), forcing the callback to allocate a read
1629 // buffer even though no data may be available. This would waste lots of
1630 // memory, since the buffer will sit around unused until the socket actually
1631 // becomes readable.
1633 // Checking if the socket is readable now also seems like it would probably
1634 // be a pessimism. In most cases it probably wouldn't be readable, and we
1635 // would just waste an extra system call. Even if it is readable, waiting to
1636 // find out from libevent on the next event loop doesn't seem that bad.
1639 void AsyncSocket::handleInitialReadWrite() noexcept {
1640 // Our callers should already be holding a DestructorGuard, but grab
1641 // one here just to make sure, in case one of our calling code paths ever
1643 DestructorGuard dg(this);
1644 // If we have a readCallback_, make sure we enable read events. We
1645 // may already be registered for reads if connectSuccess() set
1646 // the read calback.
1647 if (readCallback_ && !(eventFlags_ & EventHandler::READ)) {
1648 assert(state_ == StateEnum::ESTABLISHED);
1649 assert((shutdownFlags_ & SHUT_READ) == 0);
1650 if (!updateEventRegistration(EventHandler::READ, 0)) {
1651 assert(state_ == StateEnum::ERROR);
1654 checkForImmediateRead();
1655 } else if (readCallback_ == nullptr) {
1656 // Unregister for read events.
1657 updateEventRegistration(0, EventHandler::READ);
1660 // If we have write requests pending, try to send them immediately.
1661 // Since we just finished accepting, there is a very good chance that we can
1662 // write without blocking.
1664 // However, we only process them if EventHandler::WRITE is not already set,
1665 // which means that we're already blocked on a write attempt. (This can
1666 // happen if connectSuccess() called write() before returning.)
1667 if (writeReqHead_ && !(eventFlags_ & EventHandler::WRITE)) {
1668 // Call handleWrite() to perform write processing.
1670 } else if (writeReqHead_ == nullptr) {
1671 // Unregister for write event.
1672 updateEventRegistration(0, EventHandler::WRITE);
1676 void AsyncSocket::handleConnect() noexcept {
1677 VLOG(5) << "AsyncSocket::handleConnect() this=" << this << ", fd=" << fd_
1678 << ", state=" << state_;
1679 assert(state_ == StateEnum::CONNECTING);
1680 // SHUT_WRITE can never be set while we are still connecting;
1681 // SHUT_WRITE_PENDING may be set, be we only set SHUT_WRITE once the connect
1683 assert((shutdownFlags_ & SHUT_WRITE) == 0);
1685 // In case we had a connect timeout, cancel the timeout
1686 writeTimeout_.cancelTimeout();
1687 // We don't use a persistent registration when waiting on a connect event,
1688 // so we have been automatically unregistered now. Update eventFlags_ to
1690 assert(eventFlags_ == EventHandler::WRITE);
1691 eventFlags_ = EventHandler::NONE;
1693 // Call getsockopt() to check if the connect succeeded
1695 socklen_t len = sizeof(error);
1696 int rv = getsockopt(fd_, SOL_SOCKET, SO_ERROR, &error, &len);
1698 auto errnoCopy = errno;
1699 AsyncSocketException ex(
1700 AsyncSocketException::INTERNAL_ERROR,
1701 withAddr("error calling getsockopt() after connect"),
1703 VLOG(4) << "AsyncSocket::handleConnect(this=" << this << ", fd="
1704 << fd_ << " host=" << addr_.describe()
1705 << ") exception:" << ex.what();
1706 return failConnect(__func__, ex);
1710 AsyncSocketException ex(AsyncSocketException::NOT_OPEN,
1711 "connect failed", error);
1712 VLOG(1) << "AsyncSocket::handleConnect(this=" << this << ", fd="
1713 << fd_ << " host=" << addr_.describe()
1714 << ") exception: " << ex.what();
1715 return failConnect(__func__, ex);
1718 // Move into STATE_ESTABLISHED
1719 state_ = StateEnum::ESTABLISHED;
1721 // If SHUT_WRITE_PENDING is set and we don't have any write requests to
1722 // perform, immediately shutdown the write half of the socket.
1723 if ((shutdownFlags_ & SHUT_WRITE_PENDING) && writeReqHead_ == nullptr) {
1724 // SHUT_READ shouldn't be set. If close() is called on the socket while we
1725 // are still connecting we just abort the connect rather than waiting for
1727 assert((shutdownFlags_ & SHUT_READ) == 0);
1728 shutdown(fd_, SHUT_WR);
1729 shutdownFlags_ |= SHUT_WRITE;
1732 VLOG(7) << "AsyncSocket " << this << ": fd " << fd_
1733 << "successfully connected; state=" << state_;
1735 // Remember the EventBase we are attached to, before we start invoking any
1736 // callbacks (since the callbacks may call detachEventBase()).
1737 EventBase* originalEventBase = eventBase_;
1739 invokeConnectSuccess();
1740 // Note that the connect callback may have changed our state.
1741 // (set or unset the read callback, called write(), closed the socket, etc.)
1742 // The following code needs to handle these situations correctly.
1744 // If the socket has been closed, readCallback_ and writeReqHead_ will
1745 // always be nullptr, so that will prevent us from trying to read or write.
1747 // The main thing to check for is if eventBase_ is still originalEventBase.
1748 // If not, we have been detached from this event base, so we shouldn't
1749 // perform any more operations.
1750 if (eventBase_ != originalEventBase) {
1754 handleInitialReadWrite();
1757 void AsyncSocket::timeoutExpired() noexcept {
1758 VLOG(7) << "AsyncSocket " << this << ", fd " << fd_ << ": timeout expired: "
1759 << "state=" << state_ << ", events=" << std::hex << eventFlags_;
1760 DestructorGuard dg(this);
1761 assert(eventBase_->isInEventBaseThread());
1763 if (state_ == StateEnum::CONNECTING) {
1764 // connect() timed out
1765 // Unregister for I/O events.
1766 if (connectCallback_) {
1767 AsyncSocketException ex(
1768 AsyncSocketException::TIMED_OUT, "connect timed out");
1769 failConnect(__func__, ex);
1771 // we faced a connect error without a connect callback, which could
1772 // happen due to TFO.
1773 AsyncSocketException ex(
1774 AsyncSocketException::TIMED_OUT, "write timed out during connection");
1775 failWrite(__func__, ex);
1778 // a normal write operation timed out
1779 AsyncSocketException ex(AsyncSocketException::TIMED_OUT, "write timed out");
1780 failWrite(__func__, ex);
1784 ssize_t AsyncSocket::tfoSendMsg(int fd, struct msghdr* msg, int msg_flags) {
1785 return detail::tfo_sendmsg(fd, msg, msg_flags);
1788 AsyncSocket::WriteResult
1789 AsyncSocket::sendSocketMessage(int fd, struct msghdr* msg, int msg_flags) {
1790 ssize_t totalWritten = 0;
1791 if (state_ == StateEnum::FAST_OPEN) {
1792 sockaddr_storage addr;
1793 auto len = addr_.getAddress(&addr);
1794 msg->msg_name = &addr;
1795 msg->msg_namelen = len;
1796 totalWritten = tfoSendMsg(fd_, msg, msg_flags);
1797 if (totalWritten >= 0) {
1798 tfoFinished_ = true;
1799 state_ = StateEnum::ESTABLISHED;
1800 // We schedule this asynchrously so that we don't end up
1801 // invoking initial read or write while a write is in progress.
1802 scheduleInitialReadWrite();
1803 } else if (errno == EINPROGRESS) {
1804 VLOG(4) << "TFO falling back to connecting";
1805 // A normal sendmsg doesn't return EINPROGRESS, however
1806 // TFO might fallback to connecting if there is no
1808 state_ = StateEnum::CONNECTING;
1810 scheduleConnectTimeout();
1811 registerForConnectEvents();
1812 } catch (const AsyncSocketException& ex) {
1814 WRITE_ERROR, folly::make_unique<AsyncSocketException>(ex));
1816 // Let's fake it that no bytes were written and return an errno.
1819 } else if (errno == EOPNOTSUPP) {
1820 // Try falling back to connecting.
1821 VLOG(4) << "TFO not supported";
1822 state_ = StateEnum::CONNECTING;
1824 int ret = socketConnect((const sockaddr*)&addr, len);
1826 // connect succeeded immediately
1827 // Treat this like no data was written.
1828 state_ = StateEnum::ESTABLISHED;
1829 scheduleInitialReadWrite();
1831 // If there was no exception during connections,
1832 // we would return that no bytes were written.
1835 } catch (const AsyncSocketException& ex) {
1837 WRITE_ERROR, folly::make_unique<AsyncSocketException>(ex));
1839 } else if (errno == EAGAIN) {
1840 // Normally sendmsg would indicate that the write would block.
1841 // However in the fast open case, it would indicate that sendmsg
1842 // fell back to a connect. This is a return code from connect()
1843 // instead, and is an error condition indicating no fds available.
1846 folly::make_unique<AsyncSocketException>(
1847 AsyncSocketException::UNKNOWN, "No more free local ports"));
1850 totalWritten = ::sendmsg(fd, msg, msg_flags);
1852 return WriteResult(totalWritten);
1855 AsyncSocket::WriteResult AsyncSocket::performWrite(
1859 uint32_t* countWritten,
1860 uint32_t* partialWritten) {
1861 // We use sendmsg() instead of writev() so that we can pass in MSG_NOSIGNAL
1862 // We correctly handle EPIPE errors, so we never want to receive SIGPIPE
1863 // (since it may terminate the program if the main program doesn't explicitly
1866 msg.msg_name = nullptr;
1867 msg.msg_namelen = 0;
1868 msg.msg_iov = const_cast<iovec *>(vec);
1869 msg.msg_iovlen = std::min<size_t>(count, kIovMax);
1870 msg.msg_control = nullptr;
1871 msg.msg_controllen = 0;
1874 int msg_flags = MSG_DONTWAIT;
1876 #ifdef MSG_NOSIGNAL // Linux-only
1877 msg_flags |= MSG_NOSIGNAL;
1878 if (isSet(flags, WriteFlags::CORK)) {
1879 // MSG_MORE tells the kernel we have more data to send, so wait for us to
1880 // give it the rest of the data rather than immediately sending a partial
1881 // frame, even when TCP_NODELAY is enabled.
1882 msg_flags |= MSG_MORE;
1885 if (isSet(flags, WriteFlags::EOR)) {
1886 // marks that this is the last byte of a record (response)
1887 msg_flags |= MSG_EOR;
1889 auto writeResult = sendSocketMessage(fd_, &msg, msg_flags);
1890 auto totalWritten = writeResult.writeReturn;
1891 if (totalWritten < 0) {
1892 bool tryAgain = (errno == EAGAIN);
1894 // Apple has a bug where doing a second write on a socket which we
1895 // have opened with TFO causes an ENOTCONN to be thrown. However the
1896 // socket is really connected, so treat ENOTCONN as a EAGAIN until
1897 // this bug is fixed.
1898 tryAgain |= (errno == ENOTCONN);
1900 if (!writeResult.exception && tryAgain) {
1901 // TCP buffer is full; we can't write any more data right now.
1903 *partialWritten = 0;
1904 return WriteResult(0);
1908 *partialWritten = 0;
1912 appBytesWritten_ += totalWritten;
1914 uint32_t bytesWritten;
1916 for (bytesWritten = uint32_t(totalWritten), n = 0; n < count; ++n) {
1917 const iovec* v = vec + n;
1918 if (v->iov_len > bytesWritten) {
1919 // Partial write finished in the middle of this iovec
1921 *partialWritten = bytesWritten;
1922 return WriteResult(totalWritten);
1925 bytesWritten -= uint32_t(v->iov_len);
1928 assert(bytesWritten == 0);
1930 *partialWritten = 0;
1931 return WriteResult(totalWritten);
1935 * Re-register the EventHandler after eventFlags_ has changed.
1937 * If an error occurs, fail() is called to move the socket into the error state
1938 * and call all currently installed callbacks. After an error, the
1939 * AsyncSocket is completely unregistered.
1941 * @return Returns true on succcess, or false on error.
1943 bool AsyncSocket::updateEventRegistration() {
1944 VLOG(5) << "AsyncSocket::updateEventRegistration(this=" << this
1945 << ", fd=" << fd_ << ", evb=" << eventBase_ << ", state=" << state_
1946 << ", events=" << std::hex << eventFlags_;
1947 assert(eventBase_->isInEventBaseThread());
1948 if (eventFlags_ == EventHandler::NONE) {
1949 ioHandler_.unregisterHandler();
1953 // Always register for persistent events, so we don't have to re-register
1954 // after being called back.
1955 if (!ioHandler_.registerHandler(eventFlags_ | EventHandler::PERSIST)) {
1956 eventFlags_ = EventHandler::NONE; // we're not registered after error
1957 AsyncSocketException ex(AsyncSocketException::INTERNAL_ERROR,
1958 withAddr("failed to update AsyncSocket event registration"));
1959 fail("updateEventRegistration", ex);
1966 bool AsyncSocket::updateEventRegistration(uint16_t enable,
1968 uint16_t oldFlags = eventFlags_;
1969 eventFlags_ |= enable;
1970 eventFlags_ &= ~disable;
1971 if (eventFlags_ == oldFlags) {
1974 return updateEventRegistration();
1978 void AsyncSocket::startFail() {
1979 // startFail() should only be called once
1980 assert(state_ != StateEnum::ERROR);
1981 assert(getDestructorGuardCount() > 0);
1982 state_ = StateEnum::ERROR;
1983 // Ensure that SHUT_READ and SHUT_WRITE are set,
1984 // so all future attempts to read or write will be rejected
1985 shutdownFlags_ |= (SHUT_READ | SHUT_WRITE);
1987 if (eventFlags_ != EventHandler::NONE) {
1988 eventFlags_ = EventHandler::NONE;
1989 ioHandler_.unregisterHandler();
1991 writeTimeout_.cancelTimeout();
1994 ioHandler_.changeHandlerFD(-1);
1999 void AsyncSocket::invokeAllErrors(const AsyncSocketException& ex) {
2000 invokeConnectErr(ex);
2003 if (readCallback_) {
2004 ReadCallback* callback = readCallback_;
2005 readCallback_ = nullptr;
2006 callback->readErr(ex);
2010 void AsyncSocket::finishFail() {
2011 assert(state_ == StateEnum::ERROR);
2012 assert(getDestructorGuardCount() > 0);
2014 AsyncSocketException ex(
2015 AsyncSocketException::INTERNAL_ERROR,
2016 withAddr("socket closing after error"));
2017 invokeAllErrors(ex);
2020 void AsyncSocket::finishFail(const AsyncSocketException& ex) {
2021 assert(state_ == StateEnum::ERROR);
2022 assert(getDestructorGuardCount() > 0);
2023 invokeAllErrors(ex);
2026 void AsyncSocket::fail(const char* fn, const AsyncSocketException& ex) {
2027 VLOG(4) << "AsyncSocket(this=" << this << ", fd=" << fd_ << ", state="
2028 << state_ << " host=" << addr_.describe()
2029 << "): failed in " << fn << "(): "
2035 void AsyncSocket::failConnect(const char* fn, const AsyncSocketException& ex) {
2036 VLOG(5) << "AsyncSocket(this=" << this << ", fd=" << fd_ << ", state="
2037 << state_ << " host=" << addr_.describe()
2038 << "): failed while connecting in " << fn << "(): "
2042 invokeConnectErr(ex);
2046 void AsyncSocket::failRead(const char* fn, const AsyncSocketException& ex) {
2047 VLOG(5) << "AsyncSocket(this=" << this << ", fd=" << fd_ << ", state="
2048 << state_ << " host=" << addr_.describe()
2049 << "): failed while reading in " << fn << "(): "
2053 if (readCallback_ != nullptr) {
2054 ReadCallback* callback = readCallback_;
2055 readCallback_ = nullptr;
2056 callback->readErr(ex);
2062 void AsyncSocket::failWrite(const char* fn, const AsyncSocketException& ex) {
2063 VLOG(5) << "AsyncSocket(this=" << this << ", fd=" << fd_ << ", state="
2064 << state_ << " host=" << addr_.describe()
2065 << "): failed while writing in " << fn << "(): "
2069 // Only invoke the first write callback, since the error occurred while
2070 // writing this request. Let any other pending write callbacks be invoked in
2072 if (writeReqHead_ != nullptr) {
2073 WriteRequest* req = writeReqHead_;
2074 writeReqHead_ = req->getNext();
2075 WriteCallback* callback = req->getCallback();
2076 uint32_t bytesWritten = req->getTotalBytesWritten();
2079 callback->writeErr(bytesWritten, ex);
2086 void AsyncSocket::failWrite(const char* fn, WriteCallback* callback,
2087 size_t bytesWritten,
2088 const AsyncSocketException& ex) {
2089 // This version of failWrite() is used when the failure occurs before
2090 // we've added the callback to writeReqHead_.
2091 VLOG(4) << "AsyncSocket(this=" << this << ", fd=" << fd_ << ", state="
2092 << state_ << " host=" << addr_.describe()
2093 <<"): failed while writing in " << fn << "(): "
2097 if (callback != nullptr) {
2098 callback->writeErr(bytesWritten, ex);
2104 void AsyncSocket::failAllWrites(const AsyncSocketException& ex) {
2105 // Invoke writeError() on all write callbacks.
2106 // This is used when writes are forcibly shutdown with write requests
2107 // pending, or when an error occurs with writes pending.
2108 while (writeReqHead_ != nullptr) {
2109 WriteRequest* req = writeReqHead_;
2110 writeReqHead_ = req->getNext();
2111 WriteCallback* callback = req->getCallback();
2113 callback->writeErr(req->getTotalBytesWritten(), ex);
2119 void AsyncSocket::invalidState(ConnectCallback* callback) {
2120 VLOG(5) << "AsyncSocket(this=" << this << ", fd=" << fd_
2121 << "): connect() called in invalid state " << state_;
2124 * The invalidState() methods don't use the normal failure mechanisms,
2125 * since we don't know what state we are in. We don't want to call
2126 * startFail()/finishFail() recursively if we are already in the middle of
2130 AsyncSocketException ex(AsyncSocketException::ALREADY_OPEN,
2131 "connect() called with socket in invalid state");
2132 connectEndTime_ = std::chrono::steady_clock::now();
2133 if (state_ == StateEnum::CLOSED || state_ == StateEnum::ERROR) {
2135 callback->connectErr(ex);
2138 // We can't use failConnect() here since connectCallback_
2139 // may already be set to another callback. Invoke this ConnectCallback
2140 // here; any other connectCallback_ will be invoked in finishFail()
2143 callback->connectErr(ex);
2149 void AsyncSocket::invokeConnectErr(const AsyncSocketException& ex) {
2150 connectEndTime_ = std::chrono::steady_clock::now();
2151 if (connectCallback_) {
2152 ConnectCallback* callback = connectCallback_;
2153 connectCallback_ = nullptr;
2154 callback->connectErr(ex);
2158 void AsyncSocket::invokeConnectSuccess() {
2159 connectEndTime_ = std::chrono::steady_clock::now();
2160 if (connectCallback_) {
2161 ConnectCallback* callback = connectCallback_;
2162 connectCallback_ = nullptr;
2163 callback->connectSuccess();
2167 void AsyncSocket::invalidState(ReadCallback* callback) {
2168 VLOG(4) << "AsyncSocket(this=" << this << ", fd=" << fd_
2169 << "): setReadCallback(" << callback
2170 << ") called in invalid state " << state_;
2172 AsyncSocketException ex(AsyncSocketException::NOT_OPEN,
2173 "setReadCallback() called with socket in "
2175 if (state_ == StateEnum::CLOSED || state_ == StateEnum::ERROR) {
2177 callback->readErr(ex);
2182 callback->readErr(ex);
2188 void AsyncSocket::invalidState(WriteCallback* callback) {
2189 VLOG(4) << "AsyncSocket(this=" << this << ", fd=" << fd_
2190 << "): write() called in invalid state " << state_;
2192 AsyncSocketException ex(AsyncSocketException::NOT_OPEN,
2193 withAddr("write() called with socket in invalid state"));
2194 if (state_ == StateEnum::CLOSED || state_ == StateEnum::ERROR) {
2196 callback->writeErr(0, ex);
2201 callback->writeErr(0, ex);
2207 void AsyncSocket::doClose() {
2208 if (fd_ == -1) return;
2209 if (shutdownSocketSet_) {
2210 shutdownSocketSet_->close(fd_);
2217 std::ostream& operator << (std::ostream& os,
2218 const AsyncSocket::StateEnum& state) {
2219 os << static_cast<int>(state);
2223 std::string AsyncSocket::withAddr(const std::string& s) {
2224 // Don't use addr_ directly because it may not be initialized
2225 // e.g. if constructed from fd
2226 folly::SocketAddress peer, local;
2228 getPeerAddress(&peer);
2229 getLocalAddress(&local);
2230 } catch (const std::exception&) {
2235 return s + " (peer=" + peer.describe() + ", local=" + local.describe() + ")";
2238 void AsyncSocket::setBufferCallback(BufferCallback* cb) {
2239 bufferCallback_ = cb;