-// Copyright (C) 2011 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2012 Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.
-#include <netinet/in.h>
-#include <sys/socket.h>
-#include <unistd.h> // for some IPC/network system calls
-#include <errno.h>
-
-#include <boost/shared_array.hpp>
-
#include <config.h>
-#include <log/dummylog.h>
-
#include <asio.hpp>
#include <asio/error.hpp>
+
+#include "sync_udp_server.h"
+#include "logger.h"
+
+#include <dns/message.h>
+#include <util/buffer.h>
+
#include <asiolink/dummy_io_cb.h>
#include <asiolink/udp_endpoint.h>
#include <asiolink/udp_socket.h>
-#include "sync_udp_server.h"
-#include "logger.h"
-#include <dns/opcode.h>
+#include <boost/bind.hpp>
-using namespace asio;
-using asio::ip::udp;
-using isc::log::dlog;
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <unistd.h> // for some IPC/network system calls
+#include <errno.h>
using namespace std;
-using namespace isc::dns;
-using namespace isc::util;
+using namespace boost;
using namespace isc::asiolink;
namespace isc {
namespace asiodns {
-/*
- * Some of the member variables here are shared_ptrs and some are
- * auto_ptrs. There will be one instance of Data for the lifetime
- * of packet. The variables that are state only for a single packet
- * use auto_ptr, as it is more lightweight. In the case of shared
- * configuration (eg. the callbacks, socket), we use shared_ptrs.
- */
-struct SyncUDPServer::Data {
- /*
- * Constructors from parameters passed to UDPServer constructor.
- * This instance will not be used to retrieve and answer the actual
- * query, it will only hold parameters until we wait for the
- * first packet. But we do initialize the socket in here.
- */
- Data(io_service& io_service, const ip::address& addr, const uint16_t port,
- SimpleCallback* checkin, DNSLookup* lookup, DNSAnswer* answer) :
- io_(io_service), done_(false),
- checkin_callback_(checkin),lookup_callback_(lookup),
- answer_callback_(answer)
- {
- // We must use different instantiations for v4 and v6;
- // otherwise ASIO will bind to both
- udp proto = addr.is_v4() ? udp::v4() : udp::v6();
- socket_.reset(new udp::socket(io_service, proto));
- socket_->set_option(socket_base::reuse_address(true));
- if (addr.is_v6()) {
- socket_->set_option(asio::ip::v6_only(true));
- }
- socket_->bind(udp::endpoint(addr, port));
- }
- Data(io_service& io_service, int fd, int af, SimpleCallback* checkin,
- DNSLookup* lookup, DNSAnswer* answer) :
- io_(io_service), done_(false),
- checkin_callback_(checkin),lookup_callback_(lookup),
- answer_callback_(answer)
- {
- if (af != AF_INET && af != AF_INET6) {
- isc_throw(InvalidParameter, "Address family must be either AF_INET "
- "or AF_INET6, not " << af);
- }
- LOG_DEBUG(logger, DBGLVL_TRACE_BASIC, ASIODNS_FD_ADD_UDP).arg(fd);
- try {
- socket_.reset(new udp::socket(io_service));
- socket_->assign(af == AF_INET6 ? udp::v6() : udp::v4(), fd);
- } catch (const std::exception& exception) {
- // Whatever the thing throws, it is something from ASIO and we
- // convert it
- isc_throw(IOError, exception.what());
- }
+SyncUDPServer::SyncUDPServer(asio::io_service& io_service,
+ const asio::ip::address& addr,
+ const uint16_t port,
+ asiolink::SimpleCallback* checkin,
+ DNSLookup* lookup, DNSAnswer* answer) :
+ io_(io_service), checkin_callback_(checkin), lookup_callback_(lookup),
+ answer_callback_(answer)
+{
+ // We must use different instantiations for v4 and v6;
+ // otherwise ASIO will bind to both
+ asio::ip::udp proto = addr.is_v4() ? asio::ip::udp::v4() :
+ asio::ip::udp::v6();
+ socket_.reset(new asio::ip::udp::socket(io_service, proto));
+ socket_->set_option(asio::socket_base::reuse_address(true));
+ if (addr.is_v6()) {
+ socket_->set_option(asio::ip::v6_only(true));
}
+ socket_->bind(asio::ip::udp::endpoint(addr, port));
+}
- /*
- * Copy constructor. Default one would probably do, but it is unnecessary
- * to copy many of the member variables every time we fork to handle
- * another packet.
- *
- * We also allocate data for receiving the packet here.
- */
- Data(const Data& other) :
- io_(other.io_), socket_(other.socket_), done_(false),
- checkin_callback_(other.checkin_callback_),
- lookup_callback_(other.lookup_callback_),
- answer_callback_(other.answer_callback_)
- {
- // Instantiate the data buffer and endpoint that will
- // be used by the asynchronous receive call.
- data_.reset(new char[MAX_LENGTH]);
- sender_.reset(new udp::endpoint());
+SyncUDPServer::SyncUDPServer(asio::io_service& io_service, const int fd,
+ const int af, asiolink::SimpleCallback* checkin,
+ DNSLookup* lookup, DNSAnswer* answer) :
+ io_(io_service), checkin_callback_(checkin), lookup_callback_(lookup),
+ answer_callback_(answer)
+{
+ if (af != AF_INET && af != AF_INET6) {
+ isc_throw(InvalidParameter, "Address family must be either AF_INET "
+ "or AF_INET6, not " << af);
}
+ LOG_DEBUG(logger, DBGLVL_TRACE_BASIC, ASIODNS_FD_ADD_UDP).arg(fd);
+ try {
+ socket_.reset(new asio::ip::udp::socket(io_service));
+ socket_->assign(af == AF_INET6 ? asio::ip::udp::v6() :
+ asio::ip::udp::v4(), fd);
+ } catch (const std::exception& exception) {
+ // Whatever the thing throws, it is something from ASIO and we
+ // convert it
+ isc_throw(IOError, exception.what());
+ }
+}
- // The ASIO service object
- asio::io_service& io_;
-
- // Class member variables which are dynamic, and changes to which
- // need to accessible from both sides of a coroutine fork or from
- // outside of the coroutine (i.e., from an asynchronous I/O call),
- // should be declared here as pointers and allocated in the
- // constructor or in the coroutine. This allows state information
- // to persist when an individual copy of the coroutine falls out
- // scope while waiting for an event, *so long as* there is another
- // object that is referencing the same data. As a side-benefit, using
- // pointers also reduces copy overhead for coroutine objects.
- //
- // Note: Currently these objects are allocated by "new" in the
- // constructor, or in the function operator while processing a query.
- // Repeated allocations from the heap for every incoming query is
- // clearly a performance issue; this must be optimized in the future.
- // The plan is to have a structure pre-allocate several "Data"
- // objects which can be pulled off a free list and placed on an in-use
- // list whenever a query comes in. This will serve the dual purpose
- // of improving performance and guaranteeing that state information
- // will *not* be destroyed when any one instance of the coroutine
- // falls out of scope while waiting for an event.
- //
- // Socket used to for listen for queries. Created in the
- // constructor and stored in a shared_ptr because socket objects
- // are not copyable.
- boost::shared_ptr<asio::ip::udp::socket> socket_;
-
- // The ASIO-internal endpoint object representing the client
- std::auto_ptr<asio::ip::udp::endpoint> sender_;
-
- // \c IOMessage and \c Message objects to be passed to the
- // DNS lookup and answer providers
- std::auto_ptr<asiolink::IOMessage> io_message_;
-
- // The original query as sent by the client
- isc::dns::MessagePtr query_message_;
-
- // The response message we are building
- isc::dns::MessagePtr answer_message_;
-
- // The buffer into which the response is written
- isc::util::OutputBufferPtr respbuf_;
-
- // The buffer into which the query packet is written
- boost::shared_array<char> data_;
-
- // State information that is entirely internal to a given instance
- // of the coroutine can be declared here.
- size_t bytes_;
- bool done_;
-
-
- // Callback functions provided by the caller
- const SimpleCallback* checkin_callback_;
- const DNSLookup* lookup_callback_;
- const DNSAnswer* answer_callback_;
-
- std::auto_ptr<IOEndpoint> peer_;
- std::auto_ptr<IOSocket> iosock_;
-};
-
-/// The following functions implement the \c UDPServer class.
-///
-/// The constructor. It just creates new internal state object
-/// and lets it handle the initialization.
-SyncUDPServer::SyncUDPServer(io_service& io_service, const ip::address& addr,
- const uint16_t port, SimpleCallback* checkin,
- DNSLookup* lookup, DNSAnswer* answer) :
- data_(new Data(io_service, addr, port, checkin, lookup, answer))
-{ }
-
-SyncUDPServer::SyncUDPServer(io_service& io_service, int fd, int af,
- SimpleCallback* checkin, DNSLookup* lookup,
- DNSAnswer* answer) :
- data_(new Data(io_service, fd, af, checkin, lookup, answer))
-{ }
-
-/// The function operator is implemented with the "stackless coroutine"
-/// pattern; see internal/coroutine.h for details.
void
-SyncUDPServer::operator()(asio::error_code ec, size_t length) {
- /// Because the coroutine reentry block is implemented as
- /// a switch statement, inline variable declarations are not
- /// permitted. Certain variables used below can be declared here.
-
- CORO_REENTER (this) {
- do {
- /*
- * This is preparation for receiving a packet. We get a new
- * state object for the lifetime of the next packet to come.
- * It allocates the buffers to receive data into.
- */
- data_.reset(new Data(*data_));
-
- do {
- // Begin an asynchronous receive, then yield.
- // When the receive event is posted, the coroutine
- // will resume immediately after this point.
- CORO_YIELD data_->socket_->async_receive_from(
- buffer(data_->data_.get(), MAX_LENGTH), *data_->sender_,
- *this);
-
- // Abort on fatal errors
- // TODO: add log
- if (ec) {
- using namespace asio::error;
- if (ec.value() != would_block && ec.value() != try_again &&
- ec.value() != interrupted) {
- return;
- }
- }
-
- } while (ec || length == 0);
-
- data_->bytes_ = length;
-
- /*
- * We fork the coroutine now. One (the child) will keep
- * the current state and handle the packet, then die and
- * drop ownership of the state. The other (parent) will just
- * go into the loop again and replace the current state with
- * a new one for a new object.
- *
- * Actually, both of the coroutines will be a copy of this
- * one, but that's just internal implementation detail.
- */
- CORO_FORK data_->io_.post(SyncUDPServer(*this));
- } while (is_parent());
-
- // Create an \c IOMessage object to store the query.
- //
- // (XXX: It would be good to write a factory function
- // that would quickly generate an IOMessage object without
- // all these calls to "new".)
- data_->peer_.reset(new UDPEndpoint(*data_->sender_));
-
- // The UDP socket class has been extended with asynchronous functions
- // and takes as a template parameter a completion callback class. As
- // UDPServer does not use these extended functions (only those defined
- // in the IOSocket base class) - but needs a UDPSocket to get hold of
- // the underlying Boost UDP socket - DummyIOCallback is used. This
- // provides the appropriate operator() but is otherwise functionless.
- data_->iosock_.reset(
- new UDPSocket<DummyIOCallback>(*data_->socket_));
-
- data_->io_message_.reset(new IOMessage(data_->data_.get(),
- data_->bytes_, *data_->iosock_, *data_->peer_));
+SyncUDPServer::scheduleRead() {
+ socket_->async_receive_from(asio::buffer(data_, MAX_LENGTH), sender_,
+ boost::bind(&SyncUDPServer::handleRead, this,
+ _1, _2));
+}
- // Perform any necessary operations prior to processing an incoming
- // query (e.g., checking for queued configuration messages).
- //
- // (XXX: it may be a performance issue to check in for every single
- // incoming query; we may wish to throttle this in the future.)
- if (data_->checkin_callback_ != NULL) {
- (*data_->checkin_callback_)(*data_->io_message_);
+void
+SyncUDPServer::handleRead(const asio::error_code& ec, const size_t length) {
+ // Abort on fatal errors
+ if (ec) {
+ using namespace asio::error;
+ if (ec.value() != would_block && ec.value() != try_again &&
+ ec.value() != interrupted) {
+ return;
}
+ }
+ // Some kind of interrupt, spurious wakeup, or like that. Just try reading
+ // again.
+ if (ec || length == 0) {
+ scheduleRead();
+ return;
+ }
+ // OK, we have a real packet of data. Let's dig into it!
+
+ // XXX: This is taken (and ported) from UDPSocket class. What the hell does
+ // it really mean?
+
+ // The UDP socket class has been extended with asynchronous functions
+ // and takes as a template parameter a completion callback class. As
+ // UDPServer does not use these extended functions (only those defined
+ // in the IOSocket base class) - but needs a UDPSocket to get hold of
+ // the underlying Boost UDP socket - DummyIOCallback is used. This
+ // provides the appropriate operator() but is otherwise functionless.
+ UDPSocket<DummyIOCallback> socket(*socket_);
+ UDPEndpoint endpoint(sender_);
+ IOMessage message(data_, length, socket, endpoint);
+ if (checkin_callback_ != NULL) {
+ (*checkin_callback_)(message);
+ }
- // If we don't have a DNS Lookup provider, there's no point in
- // continuing; we exit the coroutine permanently.
- if (data_->lookup_callback_ == NULL) {
- CORO_YIELD return;
- }
+ // If we don't have a DNS Lookup provider, there's no point in
+ // continuing; we exit the coroutine permanently.
+ if (lookup_callback_ == NULL) {
+ scheduleRead();
+ return;
+ }
- // Instantiate objects that will be needed by the
- // asynchronous DNS lookup and/or by the send call.
- data_->respbuf_.reset(new OutputBuffer(0));
- data_->query_message_.reset(new Message(Message::PARSE));
- data_->answer_message_.reset(new Message(Message::RENDER));
+ // TODO: Can any of these be put to the object and reused?
+ isc::util::OutputBufferPtr output(new isc::util::OutputBuffer(0));
+ isc::dns::MessagePtr
+ query(new isc::dns::Message(isc::dns::Message::PARSE));
+ isc::dns::MessagePtr
+ answer(new isc::dns::Message(isc::dns::Message::RENDER));
- // Schedule a DNS lookup, and yield. When the lookup is
- // finished, the coroutine will resume immediately after
- // this point.
- CORO_YIELD data_->io_.post(AsyncLookup<SyncUDPServer>(*this));
+ // Mark that we don't have an answer yet.
+ done_ = false;
+ resume_called_ = false;
- // The 'done_' flag indicates whether we have an answer
- // to send back. If not, exit the coroutine permanently.
- if (!data_->done_) {
- CORO_YIELD return;
- }
+ // Call the actual lookup
+ (*lookup_callback_)(message, query, answer, output, this);
- // Call the DNS answer provider to render the answer into
- // wire format
- (*data_->answer_callback_)(*data_->io_message_, data_->query_message_,
- data_->answer_message_, data_->respbuf_);
+ if (!resume_called_) {
+ isc_throw(isc::Unexpected,
+ "No resume called from the lookup callback");
+ }
+
+ if (done_) {
+ // Good, there's an answer.
+ // Call the answer callback to render it.
+ (*answer_callback_)(message, query, answer, output);
- // Begin an asynchronous send, and then yield. When the
- // send completes, we will resume immediately after this point
- // (though we have nothing further to do, so the coroutine
- // will simply exit at that time).
- CORO_YIELD data_->socket_->async_send_to(
- buffer(data_->respbuf_->getData(), data_->respbuf_->getLength()),
- *data_->sender_, *this);
+ socket_->send_to(asio::buffer(output->getData(), output->getLength()),
+ sender_);
}
+
+ // And schedule handling another socket.
+ scheduleRead();
}
-/// Call the DNS lookup provider. (Expected to be called by the
-/// AsyncLookup<UDPServer> handler.)
void
-SyncUDPServer::asyncLookup() {
- (*data_->lookup_callback_)(*data_->io_message_,
- data_->query_message_, data_->answer_message_, data_->respbuf_, this);
+SyncUDPServer::operator()(asio::error_code, size_t) {
+ // To start the server, we just schedule reading of data when they
+ // arrive.
+ scheduleRead();
}
/// Stop the UDPServer
/// for it won't be scheduled by io service not matter it is
/// submit to io serice before or after close call. And we will
//. get bad_descriptor error
- data_->socket_->close();
+ socket_->close();
}
/// Post this coroutine on the ASIO service queue so that it will
/// whether there is an answer to return to the client.
void
SyncUDPServer::resume(const bool done) {
- data_->done_ = done;
- data_->io_.post(*this);
+ resume_called_ = true;
+ done_ = done;
}
bool
SyncUDPServer::hasAnswer() {
- return (data_->done_);
+ return (done_);
}
} // namespace asiodns
-// Copyright (C) 2011 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2012 Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
#error "asio.hpp must be included before including this, see asiolink.h as to why"
#endif
+#include "dns_answer.h"
+#include "dns_lookup.h"
+#include "dns_server.h"
+
#include <asiolink/simple_callback.h>
-#include <asiodns/dns_answer.h>
-#include <asiodns/dns_lookup.h>
-#include <asiodns/dns_server.h>
+#include <exceptions.h>
-#include <coroutine.h>
+#include <boost/noncopyable.hpp>
namespace isc {
namespace asiodns {
-//
-// Asynchronous UDP server coroutine
-//
+/// \brief An UDP server that doesn't asynchronous lookup handlers.
///
-/// \brief This class implements the coroutine to handle UDP
-/// DNS query event. As such, it is both a \c DNSServer and
-/// a \c coroutine
-///
-class SyncUDPServer : public virtual DNSServer, public virtual coroutine {
+/// That means, the lookup handler must provide the answer right away.
+/// This allows for implementation with less overhead, compared with
+/// the UDPClass.
+class SyncUDPServer : public DNSServer, public boost::noncopyable {
public:
/// \brief Constructor
/// \param io_service the asio::io_service to work with
/// \param lookup the callbackprovider for DNS lookup events
/// \param answer the callbackprovider for DNS answer events
explicit SyncUDPServer(asio::io_service& io_service,
- const asio::ip::address& addr, const uint16_t port,
- isc::asiolink::SimpleCallback* checkin = NULL,
- DNSLookup* lookup = NULL,
- DNSAnswer* answer = NULL);
+ const asio::ip::address& addr, const uint16_t port,
+ isc::asiolink::SimpleCallback* checkin = NULL,
+ DNSLookup* lookup = NULL,
+ DNSAnswer* answer = NULL);
/// \brief Constructor
/// \param io_service the asio::io_service to work with
/// \throw isc::InvalidParameter if af is neither AF_INET nor AF_INET6
/// \throw isc::asiolink::IOError when a low-level error happens, like the
/// fd is not a valid descriptor.
- SyncUDPServer(asio::io_service& io_service, int fd, int af,
- isc::asiolink::SimpleCallback* checkin = NULL,
- DNSLookup* lookup = NULL, DNSAnswer* answer = NULL);
+ SyncUDPServer(asio::io_service& io_service, const int fd, const int af,
+ isc::asiolink::SimpleCallback* checkin = NULL,
+ DNSLookup* lookup = NULL, DNSAnswer* answer = NULL);
- /// \brief The function operator
- void operator()(asio::error_code ec = asio::error_code(),
+ /// \brief Start the SyncUDPServer.
+ ///
+ /// This is the function operator to keep interface with other server
+ /// classes. They need that because they're coroutines.
+ virtual void operator()(asio::error_code ec = asio::error_code(),
size_t length = 0);
/// \brief Calls the lookup callback
- void asyncLookup();
+ virtual void asyncLookup() {
+ isc_throw(Unexpected,
+ "SyncUDPServer doesn't support asyncLookup by design, use "
+ "UDPServer if you need it.");
+ }
/// \brief Stop the running server
/// \note once the server stopped, it can't restart
- void stop();
+ virtual void stop();
/// \brief Resume operation
///
+ /// Note that unlike other servers, this one expects it to be called
+ /// directly from the lookup callback. If it isn't, the server will
+ /// throw an Unexpected exception (probably to the event loop, which
+ /// would usually lead to termination of the program, but that's OK,
+ /// as it would be serious programmer error).
+ ///
/// \param done Set this to true if the lookup action is done and
/// we have an answer
- void resume(const bool done);
+ virtual void resume(const bool done);
/// \brief Check if we have an answer
///
/// \return true if we have an answer
- bool hasAnswer();
-
- /// \brief Returns the coroutine state value
- ///
- /// \return the coroutine state value
- int value() { return (get_value()); }
+ virtual bool hasAnswer();
/// \brief Clones the object
///
/// \return a newly allocated copy of this object
- DNSServer* clone() {
- SyncUDPServer* s = new SyncUDPServer(*this);
- return (s);
+ virtual DNSServer* clone() {
+ isc_throw(Unexpected, "SyncUDPServer can't be cloned.");
}
-
private:
- enum { MAX_LENGTH = 4096 };
-
- /**
- * \brief Internal state and data.
- *
- * We use the pimple design pattern, but not because we need to hide
- * internal data. This class and whole header is for private use anyway.
- * It turned out that SyncUDPServer is copied a lot, because it is a coroutine.
- * This way the overhead of copying is lower, we copy only one shared
- * pointer instead of about 10 of them.
- */
- struct Data;
- boost::shared_ptr<Data> data_;
+ static const size_t MAX_LENGTH = 4096;
+ uint8_t data_[MAX_LENGTH];
+ std::auto_ptr<asio::ip::udp::socket> socket_;
+ asio::io_service& io_;
+ asio::ip::udp::endpoint sender_;
+ const asiolink::SimpleCallback* checkin_callback_;
+ const DNSLookup* lookup_callback_;
+ const DNSAnswer* answer_callback_;
+ bool resume_called_, done_;
+
+ void scheduleRead();
+ void handleRead(const asio::error_code& ec, const size_t length);
};
} // namespace asiodns
projects / thirdparty / kea.git / commitdiff
