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MQTTClient.cpp
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MQTTClient.cpp
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// We need our implementation
#include <Network/Clients/MQTT.hpp>
#if MQTTUseAuth == 1
/** Used to track reentrancy in the AUTH recursive scheme */
enum AuthReentrancy
{
FromConnect = 0x80000000,
AuthMask = 0x7FFFFFFF,
};
#endif
#if MQTTOnlyBSDSocket != 1
#pragma message("This configuration is not supported and depends on external code in tests folder that is not exported upon install")
// We need socket declaration
#include "Network/Socket.hpp"
// We need SSL socket declaration too
//#include "../../../include/Network/SSLSocket.hpp"
// We need FastLock too
#include "Threading/Lock.hpp"
#else
// We need BSD socket here
#include <sys/socket.h>
// We need gethostbyname or getaddrinfo
#include <netdb.h>
// We need TCP_NODELAY
#include <netinet/tcp.h>
// We need std::atomic too
#include <atomic>
#if MQTTUseTLS == 1
// We need MBedTLS code
#include <mbedtls/certs.h>
#include <mbedtls/ctr_drbg.h>
#include <mbedtls/entropy.h>
#include <mbedtls/error.h>
#include <mbedtls/net_sockets.h>
#include <mbedtls/platform.h>
#include <mbedtls/ssl.h>
#endif
#endif
// We need StackHeapBuffer to avoid stressing the heap allocator when it's not required
#include <Platform/StackHeapBuffer.hpp>
#if MQTTDumpCommunication == 1
// We need hexDump
#include "Utils/Dump.hpp"
#endif
// This is the maximum allocation that'll be performed on the stack before it's being replaced by heap allocation
// This also means that the stack size for the thread using such function must be larger than this value
#define StackSizeAllocationLimit 512
namespace Network { namespace Client {
#if MQTTOnlyBSDSocket != 1
/* The socket class we are using for socket operations.
There's a default implementation for Berkeley socket and (Open)SSL socket in the ClassPath, but
you can implement any library you want, like, for example, lwIP, so change this if you do */
typedef Network::Socket::BerkeleySocket Socket;
#if MQTTUseTLS == 1
/* The SSL socket we are using (when using SSL/TLS connection).
There's a default implementation for (Open/Libre)SSL socket in ClassPath, but you can implement
one class with, for example, MBEDTLS here if you want. Change this if you do */
typedef Network::Socket::SSL_TLS SSLSocket;
/** The SSL context to (re)use. If you need to skip negotiating, you'll need to modify this context */
typedef SSLSocket::SSLContext SSLContext;
#endif
/** The scoped lock class we are using */
typedef Threading::ScopedLock ScopedLock;
struct MQTTv5::Impl
{
/** The multithread protection for this object */
Threading::Lock lock;
/** This client socket */
Socket * socket;
/** The DER encoded certificate (if provided) */
const DynamicBinDataView * brokerCert;
#if MQTTUseTLS == 1
/** The SSL context (if any used) */
SSLContext * sslContext;
#endif
/** This client unique identifier */
DynamicString clientID;
/** The message received callback to use */
MessageReceived * cb;
/** The default timeout in milliseconds */
uint32 timeoutMs;
/** The last communication time in second */
uint32 lastCommunication;
/** The publish current default identifier allocator */
uint16 publishCurrentId;
/** The keep alive delay in seconds */
uint16 keepAlive;
/** The reading state. Because data on a TCP stream is
a stream, we have to remember what state we are currently following while parsing data */
enum RecvState
{
Ready = 0,
GotType,
GotLength,
GotCompletePacket,
} recvState;
/** The receiving buffer size */
uint32 recvBufferSize;
/** The maximum packet size the server is willing to accept */
uint32 maxPacketSize;
/** The available data in the buffer */
uint32 available;
/** The receiving data buffer */
uint8 * recvBuffer;
/** The receiving VBInt size for the packet header */
uint8 packetExpectedVBSize;
#if MQTTUseAuth == 1
/** Used to track the origin of the AUTH exchange */
uint32 authSource;
#endif
uint16 allocatePacketID()
{
return ++publishCurrentId;
}
Impl(const char * clientID, MessageReceived * callback, const DynamicBinDataView * brokerCert)
: socket(0), brokerCert(brokerCert),
#if MQTTUseTLS == 1
sslContext(0),
#endif
#if MQTTUseAuth == 1
authSource(0),
#endif
clientID(clientID), cb(callback), timeoutMs(3000), lastCommunication(0), publishCurrentId(0), keepAlive(300),
recvState(Ready), recvBufferSize(max(callback->maxPacketSize(), 8U)), maxPacketSize(65535), available(0), recvBuffer((uint8*)::malloc(recvBufferSize)), packetExpectedVBSize(Protocol::MQTT::Common::VBInt(recvBufferSize).getSize())
{}
~Impl() { delete socket; socket = 0; ::free(recvBuffer); recvBuffer = 0; recvBufferSize = 0; }
inline void setTimeout(uint32 timeout) { timeoutMs = timeout; }
bool shouldPing()
{
return (((uint32)time(NULL) - lastCommunication) >= keepAlive);
}
int send(const char * buffer, const uint32 length)
{
if (!socket) return -1;
#if MQTTDumpCommunication == 1
// Dump the packet to send
String packetDump;
Utils::hexDump(packetDump, (const uint8*)buffer, length, 16, true, true);
Protocol::MQTT::V5::FixedHeader header;
header.raw = buffer[0];
Logger::log(Logger::Dump, "> Sending packet: %s(R:%d,Q:%d,D:%d)%s", Protocol::MQTT::V5::Helper::getControlPacketName((Protocol::MQTT::Common::ControlPacketType)(uint8)header.type), header.retain, header.QoS, header.dup, (const char*)packetDump);
#endif
return socket->sendReliably(buffer, (int)length, timeoutMs);
}
bool hasValidLength() const
{
Protocol::MQTT::Common::VBInt l;
return l.readFrom(recvBuffer + 1, available - 1) != Protocol::MQTT::Common::BadData;
}
/** Receive a control packet from the socket in the given time.
@retval positive The number of bytes received
@retval 0 Protocol error, you should close the socket
@retval -1 Socket error
@retval -2 Timeout */
int receiveControlPacket(const bool lowLatency = false)
{
if (!socket) return -1;
// Depending on the current state, we need to fetch as many bytes as possible within the given timeoutMs
// This is a complex problem here because we want both to optimize for
// - latency (returns as fast as possible when we've received a complete packet)
// - blocking time (don't return immediately if the data is currently in transfer, need to wait for it to arrive)
// - minimal syscalls (don't call recv byte per byte as the overhead will be significant)
// - network queue (don't fetch more byte than necessary for getting a single control packet)
// - streaming usage (this can be called while a control packet was being received and we timed out)
// So the algorithm used here depends on the current receiving state
// If we haven't received packet length yet, we have to fetch the header very carefully
// Else, we can enter a more general receiving loop until we have all bytes from the control packet
int ret = 0;
Protocol::MQTT::Common::VBInt len;
#if MQTTLowLatency == 1
// In low latency mode, return as early as possible
if (lowLatency && !socket->select(true, false, 0)) return -2;
#endif
// We want to keep track of complete timeout time over multiple operations
Time::TimeOut timeout(timeoutMs);
switch (recvState)
{
case Ready:
case GotType:
{ // Here, make sure we only fetch the length first
// The minimal size is 2 bytes for PINGRESP, DISCONNECT and AUTH.
// Because of this, we can't really outsmart the system everytime
ret = socket->receiveReliably((char*)&recvBuffer[available], 2 - available, timeout);
if (ret > 0) available += ret;
// Deal with timeout first
if (timeout == 0) return -2;
// Deal with socket errors here
if (ret < 0 || available < 2) return -1;
// Depending on the packet type, let's wait for more data
if (recvBuffer[0] < 0xD0 || recvBuffer[1]) // Below ping response or packet size larger than 2 bytes
{
int querySize = (packetExpectedVBSize + 1) - available;
ret = socket->receiveReliably((char*)&recvBuffer[available], querySize, timeout);
if (ret > 0) available += ret;
// Deal with timeout first
if (timeout == 0) return -2;
// Deal with socket errors here
if (ret < 0) return ret;
}
recvState = GotLength;
break;
}
default: break;
}
// Here we should either have a valid control packet header
uint32 r = len.readFrom(&recvBuffer[1], available - 1);
if (r == Protocol::MQTT::Common::BadData)
return 0; // Close the socket here, the given data are wrong or not the right protocol
if (r == Protocol::MQTT::Common::NotEnoughData)
{
if (available >= (packetExpectedVBSize+1))
{ // The server sends us a packet that's larger than the expected maximum size,
// In MQTTv5 it's a protocol error, so let's disconnect
return 0;
}
// We haven't received enough data in the given timeout to make progress, let's report a timeout
recvState = GotType;
return -2;
}
uint32 remainingLength = len;
uint32 totalPacketSize = remainingLength + 1 + len.getSize();
ret = totalPacketSize == available ? 0 : socket->receiveReliably((char*)&recvBuffer[available], (totalPacketSize - available), timeout);
if (ret > 0) available += ret;
if (timeout == 0) return -2;
if (ret < 0) return ret;
// Ok, let's check if we have received the complete packet
if (available == totalPacketSize)
{
recvState = GotCompletePacket;
#if MQTTDumpCommunication == 1
// Dump the packet received
String packetDump;
Utils::hexDump(packetDump, recvBuffer, available, 16, true, true);
Protocol::MQTT::V5::FixedHeader header;
header.raw = recvBuffer[0];
Logger::log(Logger::Dump, "< Received packet: %s(R:%d,Q:%d,D:%d)%s", Protocol::MQTT::V5::Helper::getControlPacketName((Protocol::MQTT::Common::ControlPacketType)(uint8)header.type), header.retain, header.QoS, header.dup, (const char*)packetDump);
#endif
lastCommunication = (uint32)time(NULL);
return (int)available;
}
// No yet, but we probably timed-out.
return -2;
}
/** Get the last received packet type */
Protocol::MQTT::V5::ControlPacketType getLastPacketType() const
{
if (recvState != GotCompletePacket) return Protocol::MQTT::V5::RESERVED;
Protocol::MQTT::V5::FixedHeader header;
header.raw = recvBuffer[0];
return (Protocol::MQTT::V5::ControlPacketType)(uint8)header.type;
}
/** Extract a control packet of the given type */
int extractControlPacket(const Protocol::MQTT::V5::ControlPacketType type, Protocol::MQTT::Common::Serializable & packet)
{
if (recvState != GotCompletePacket)
{
int ret = receiveControlPacket();
if (ret <= 0) return ret;
if (recvState != GotCompletePacket)
return -2;
}
// Check the packet is the last expected type
if (getLastPacketType() != type) return -3;
// Seems to be the expected type, let's unserialize it
uint32 r = packet.readFrom(recvBuffer, recvBufferSize);
if (Protocol::MQTT::Common::isError(r)) return -4; // Parsing error
// Done with receiving the packet let's remember it
resetPacketReceivingState();
#if MQTTDumpCommunication == 1
MQTTString out;
packet.dump(out, 2);
Logger::log(Logger::Dump, "Received\n%.*s", MQTTStringGetLength(out), MQTTStringGetData(out));
#endif
return (int)r;
}
void resetPacketReceivingState() { recvState = Ready; available = 0; }
void close()
{
delete0(socket);
}
bool isOpen()
{
return socket != nullptr;
}
int connectWith(const char * host, const uint16 port, const bool withTLS)
{
if (isOpen()) return -1;
if (withTLS)
{
#if MQTTUseTLS == 1
if (!sslContext)
{ // If one certificate is given let's use it instead of the default CA bundle
sslContext = brokerCert ? new SSLContext(NULL, Crypto::SSLContext::Any) : new SSLContext();
}
if (!sslContext) return -2;
// Insert here any session specific configuration or certificate validator
if (brokerCert)
{
if (const char * error = sslContext->loadCertificateFromDER(brokerCert->data, brokerCert->length))
{
Logger::log(Logger::Error, "Could not load the given certificate: %s", error);
return -2;
}
}
socket = new Network::Socket::SSL_TLS(*sslContext, Network::Socket::BaseSocket::Stream);
#else
return -1;
#endif
} else socket = new Socket(Network::Socket::BaseSocket::Stream);
if (!socket) return -2;
// Let the socket be asynchronous and without Nagle's algorithm
if (!socket->setOption(Network::Socket::BaseSocket::Blocking, 0)) return -3;
if (!socket->setOption(Network::Socket::BaseSocket::NoDelay, 1)) return -4;
if (!socket->setOption(Network::Socket::BaseSocket::NoSigPipe, 1)) return -5;
// Then connect the socket to the server
int ret = socket->connect(Network::Address::URL("", String(host) + ":" + port, ""));
if (ret < 0) return -6;
if (ret == 0) return 0;
// Here, we need to wait until connection happens or times out
if (socket->select(false, true, timeoutMs)) return 0;
return -7;
}
#if MQTTUseAuth == 1
MQTTv5::ErrorType handleAuth()
{
Protocol::MQTT::V5::ROAuthPacket packet;
int ret = extractControlPacket(Protocol::MQTT::V5::AUTH, packet);
if (ret > 0)
{
// Parse the Auth packet and call the user method
// Try to find the auth method, and the auth data
DynamicStringView authMethod;
DynamicBinDataView authData;
Protocol::MQTT::V5::VisitorVariant visitor;
while (packet.props.getProperty(visitor) && (authMethod.length == 0 || authData.length == 0))
{
if (visitor.propertyType() == Protocol::MQTT::V5::AuthenticationMethod)
{
auto view = visitor.as< DynamicStringView >();
authMethod = *view;
}
else if (visitor.propertyType() == Protocol::MQTT::V5::AuthenticationData)
{
auto data = visitor.as< DynamicBinDataView >();
authData = *data;
}
}
return cb->authReceived(packet.fixedVariableHeader.reason(), authMethod, authData, packet.props) ? MQTTv5::ErrorType::Success : MQTTv5::ErrorType::NetworkError;
}
return ErrorType::NetworkError;
}
#endif
MQTTv5::ErrorType handleConnACK()
{
// Parse the ConnACK packet;
Protocol::MQTT::V5::ROConnACKPacket packet;
int ret = extractControlPacket(Protocol::MQTT::V5::CONNACK, packet);
if (ret > 0)
{
// We are only interested in the result of the connection
if (packet.fixedVariableHeader.acknowledgeFlag & 1)
{ // Session is present on the server. For now, we don't care, do we ?
}
if (packet.fixedVariableHeader.reasonCode != 0
#if MQTTUseAuth == 1
&& packet.fixedVariableHeader.reasonCode != Protocol::MQTT::V5::NotAuthorized
&& packet.fixedVariableHeader.reasonCode != Protocol::MQTT::V5::BadAuthenticationMethod
#endif
)
{
// We have failed connection with the following reason:
return (MQTTv5::ReasonCodes)packet.fixedVariableHeader.reasonCode;
}
// Now, we are going to parse the other properties
#if MQTTUseAuth == 1
DynamicStringView authMethod;
DynamicBinDataView authData;
#endif
Protocol::MQTT::V5::VisitorVariant visitor;
while (packet.props.getProperty(visitor))
{
switch (visitor.propertyType())
{
case Protocol::MQTT::V5::PacketSizeMax:
{
auto pod = visitor.as< Protocol::MQTT::V5::LittleEndianPODVisitor<uint32> >();
maxPacketSize = pod->getValue();
break;
}
case Protocol::MQTT::V5::AssignedClientID:
{
auto view = visitor.as< Protocol::MQTT::V5::DynamicStringView >();
clientID.from(view->data, view->length); // This allocates memory for holding the copy
break;
}
case Protocol::MQTT::V5::ServerKeepAlive:
{
auto pod = visitor.as< Protocol::MQTT::V5::LittleEndianPODVisitor<uint16> >();
keepAlive = (pod->getValue() + (pod->getValue()>>1)) >> 1; // Use 0.75 of the server's told value
break;
}
#if MQTTUseAuth == 1
case Protocol::MQTT::V5::AuthenticationMethod:
{
auto view = visitor.as<DynamicStringView>();
authMethod = *view;
} break;
case Protocol::MQTT::V5::AuthenticationData:
{
auto data = visitor.as<DynamicBinDataView>();
authData = *data;
} break;
#endif
// Actually, we don't care about other properties. Maybe we should ?
default: break;
}
}
#if MQTTUseAuth == 1
if (packet.fixedVariableHeader.reasonCode == Protocol::MQTT::V5::NotAuthorized
|| packet.fixedVariableHeader.reasonCode == Protocol::MQTT::V5::BadAuthenticationMethod)
{ // Let the user be aware of the required authentication properties so next connect will/can contains them
return cb->authReceived((ReasonCodes)packet.fixedVariableHeader.reasonCode, authMethod, authData, packet.props) ? ErrorType::Success : ErrorType::NetworkError;
}
#endif
return ErrorType::Success;
}
return Protocol::MQTT::V5::ProtocolError;
}
};
#else
#ifndef MQTTLock
/* If you have a true lock object in your system (for example, in FreeRTOS, use a mutex),
you should provide one instead of this one as this one just burns CPU while waiting */
class SpinLock
{
mutable std::atomic<bool> state;
public:
/** Construction */
SpinLock() : state(false) {}
/** Acquire the lock */
inline void acquire() volatile
{
while (state.exchange(true, std::memory_order_acq_rel))
{
// Put a sleep method here (using select here since it's cross platform in BSD socket API)
struct timeval tv;
tv.tv_sec = 0; tv.tv_usec = 500; // Wait 0.5ms per loop
select(0, NULL, NULL, NULL, &tv);
}
}
/** Try to acquire the lock */
inline bool tryAcquire() volatile { return state.exchange(true, std::memory_order_acq_rel) == false; }
/** Check if the lock is taken. For debugging purpose only */
inline bool isLocked() const volatile { return state.load(std::memory_order_consume); }
/** Release the lock */
inline void release() volatile { state.store(false, std::memory_order_release);; }
};
typedef SpinLock Lock;
struct ScopedLock
{
Lock & a;
ScopedLock(Lock & a) : a(a) { a.acquire(); }
~ScopedLock() { a.release(); }
};
#else
#define Lock MQTTLock
#define ScopedLock MQTTScopedLock
#endif
#ifndef closesocket
#define closesocket close
#endif
#ifndef MSG_NOSIGNAL
#define MSG_NOSIGNAL 0
#endif
#if MQTTDumpCommunication == 1
static void hexdump(const void * buf, int len)
{
for (int i = 0; i < len; i++)
printf("%02X ", ((unsigned char*)buf)[i]);
printf("\n"); // Flush output
}
static void dumpBufferAsPacket(const char * prompt, const uint8* buffer, uint32 length)
{
// Dump the packet to send
Protocol::MQTT::V5::FixedHeader header;
header.raw = buffer[0];
printf("%s: %s(R:%d,Q:%d,D:%d)\n", prompt, Protocol::MQTT::V5::Helper::getControlPacketName((Protocol::MQTT::Common::ControlPacketType)(uint8)header.type), (uint8)header.retain, (uint8)header.QoS, (uint8)header.dup);
hexdump(buffer, length);
}
#endif
#if MQTTUseTLS == 1
// Small optimization to remove useless virtual table in the final binary if not used
#define MQTTVirtual virtual
#else
#define MQTTVirtual
#endif
struct BaseSocket
{
int socket;
struct timeval & timeoutMs;
MQTTVirtual int connect(const char * host, uint16 port, const MQTTv5::DynamicBinDataView *)
{
socket = ::socket(AF_INET, SOCK_STREAM, 0);
if (socket == -1) return -2;
// Please notice that under linux, it's not required to set the socket
// as non blocking if you define SO_SNDTIMEO, for connect timeout.
// so the code below could be optimized away. Yet, lwIP does show the
// same behavior so when a timeout for connection is actually required
// you must issue a select call here.
// Set non blocking here
int socketFlags = ::fcntl(socket, F_GETFL, 0);
if (socketFlags == -1) return -3;
if (::fcntl(socket, F_SETFL, (socketFlags | O_NONBLOCK)) != 0) return -3;
// Let the socket be without Nagle's algorithm
int flag = 1;
if (::setsockopt(socket, IPPROTO_TCP, TCP_NODELAY, &flag, sizeof(flag)) < 0) return -4;
// Then connect the socket to the server
struct addrinfo hints = {};
hints.ai_family = AF_INET; // IPv4 only for now
hints.ai_flags = AI_ADDRCONFIG;
hints.ai_socktype = SOCK_STREAM;
// Resolve address
struct addrinfo *result = NULL;
if (getaddrinfo(host, NULL, &hints, &result) < 0 || result == NULL) return -5;
// Then connect to it
struct sockaddr_in address;
address.sin_port = htons(port);
address.sin_family = AF_INET;
address.sin_addr = ((struct sockaddr_in *)(result->ai_addr))->sin_addr;
// free result
freeaddrinfo(result);
int ret = ::connect(socket, (const sockaddr*)&address, sizeof(address));
if (ret < 0 && errno != EINPROGRESS) return -6;
if (ret == 0) return 0;
// Here, we need to wait until connection happens or times out
if (select(false, true))
{
// Restore blocking behavior here
if (::fcntl(socket, F_SETFL, socketFlags) != 0) return -3;
// And set timeouts for both recv and send
if (::setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, &timeoutMs, sizeof(timeoutMs)) < 0) return -4;
if (::setsockopt(socket, SOL_SOCKET, SO_SNDTIMEO, &timeoutMs, sizeof(timeoutMs)) < 0) return -4;
// Ok, done!
return 0;
}
return -7;
}
MQTTVirtual int recv(char * buffer, const uint32 minLength, const uint32 maxLength = 0)
{
int ret = ::recv(socket, buffer, minLength, MSG_WAITALL);
if (ret <= 0) return ret;
if (maxLength <= minLength) return ret;
int nret = ::recv(socket, &buffer[ret], maxLength - ret, 0);
return nret <= 0 ? nret : nret + ret;
}
MQTTVirtual int send(const char * buffer, const uint32 length)
{
#if MQTTDumpCommunication == 1
dumpBufferAsPacket("> Sending packet", (const uint8*)buffer, length);
#endif
return ::send(socket, buffer, (int)length, 0);
}
// Useful socket helpers functions here
MQTTVirtual int select(bool reading, bool writing, bool instantaneous = false)
{
// Linux modifies the timeout when calling select
struct timeval v = timeoutMs;
if (instantaneous) memset(&v, 0, sizeof(v));
fd_set set;
FD_ZERO(&set);
FD_SET(socket, &set);
// Then select
return ::select(socket + 1, reading ? &set : NULL, writing ? &set : NULL, NULL, &v);
}
BaseSocket(struct timeval & timeoutMs) : socket(-1), timeoutMs(timeoutMs) {}
MQTTVirtual ~BaseSocket() { ::closesocket(socket); socket = -1; }
};
#if MQTTUseTLS == 1
class MBTLSSocket : public BaseSocket
{
mbedtls_entropy_context entropy;
mbedtls_ctr_drbg_context entropySource;
mbedtls_ssl_context ssl;
mbedtls_ssl_config conf;
mbedtls_x509_crt cacert;
mbedtls_net_context net;
private:
bool buildConf(const MQTTv5::DynamicBinDataView * brokerCert)
{
if (brokerCert)
{ // Use given root certificate (if you have a recent version of mbedtls, you could use mbedtls_x509_crt_parse_der_nocopy instead to skip a useless copy here)
if (::mbedtls_x509_crt_parse_der(&cacert, brokerCert->data, brokerCert->length))
return false;
}
// Now create configuration from default
if (::mbedtls_ssl_config_defaults(&conf, MBEDTLS_SSL_IS_CLIENT, MBEDTLS_SSL_TRANSPORT_STREAM, MBEDTLS_SSL_PRESET_DEFAULT))
return false;
::mbedtls_ssl_conf_ca_chain(&conf, &cacert, NULL);
::mbedtls_ssl_conf_authmode(&conf, brokerCert ? MBEDTLS_SSL_VERIFY_REQUIRED : MBEDTLS_SSL_VERIFY_NONE);
uint32_t ms = timeoutMs.tv_usec / 1000;
::mbedtls_ssl_conf_read_timeout(&conf, ms < 50 ? 3000 : ms);
// Random number generator
::mbedtls_ssl_conf_rng(&conf, ::mbedtls_ctr_drbg_random, &entropySource);
if (::mbedtls_ctr_drbg_seed(&entropySource, ::mbedtls_entropy_func, &entropy, NULL, 0))
return false;
if (::mbedtls_ssl_setup(&ssl, &conf))
return false;
return true;
}
public:
MBTLSSocket(struct timeval & timeoutMs) : BaseSocket(timeoutMs)
{
mbedtls_ssl_init(&ssl);
mbedtls_ssl_config_init(&conf);
mbedtls_x509_crt_init(&cacert);
mbedtls_ctr_drbg_init(&entropySource);
mbedtls_entropy_init(&entropy);
}
int connect(const char * host, uint16 port, const MQTTv5::DynamicBinDataView * brokerCert)
{
int ret = BaseSocket::connect(host, port, 0);
if (ret) return ret;
// MBedTLS doesn't deal with natural socket timeout correctly, so let's fix that
struct timeval zeroTO = {};
if (::setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, &zeroTO, sizeof(zeroTO)) < 0) return -4;
if (::setsockopt(socket, SOL_SOCKET, SO_SNDTIMEO, &zeroTO, sizeof(zeroTO)) < 0) return -4;
net.fd = socket;
if (!buildConf(brokerCert)) return -8;
if (::mbedtls_ssl_set_hostname(&ssl, host)) return -9;
// Set the method the SSL engine is using to fetch/send data to the other side
::mbedtls_ssl_set_bio(&ssl, &net, ::mbedtls_net_send, NULL, ::mbedtls_net_recv_timeout);
ret = ::mbedtls_ssl_handshake(&ssl);
if (ret != 0 && ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE)
return -10;
// Check certificate if one provided
if (brokerCert)
{
uint32_t flags = mbedtls_ssl_get_verify_result(&ssl);
if (flags != 0)
{
#if MQTTDumpCommunication == 1
char verify_buf[100] = {0};
mbedtls_x509_crt_verify_info(verify_buf, sizeof(verify_buf), " ! ", flags);
printf("mbedtls_ssl_get_verify_result: %s flag: 0x%x\n", verify_buf, (unsigned int)flags);
#endif
return -11;
}
}
return 0;
}
int send(const char * buffer, const uint32 length)
{
#if MQTTDumpCommunication == 1
dumpBufferAsPacket("> Sending packet", (const uint8*)buffer, length);
#endif
return ::mbedtls_ssl_write(&ssl, (const uint8*)buffer, length);
}
int recv(char * buffer, const uint32 minLength, const uint32 maxLength = 0)
{
uint32 ret = 0;
while (ret < minLength)
{
int r = ::mbedtls_ssl_read(&ssl, (uint8*)&buffer[ret], minLength - ret);
if (r <= 0)
{
// Those means that we need to call again the read method
if (r == MBEDTLS_ERR_SSL_WANT_READ || r == MBEDTLS_ERR_SSL_WANT_WRITE)
continue;
if (r == MBEDTLS_ERR_SSL_TIMEOUT) {
errno = EWOULDBLOCK; // Remember it's a timeout
return -1;
}
return ret ? (int)ret : r; // Silent error here
}
ret += (uint32)r;
}
if (maxLength <= minLength) return ret;
// This one is a non blocking call
int nret = ::mbedtls_ssl_read(&ssl, (uint8*)&buffer[ret], maxLength - ret);
if (nret == MBEDTLS_ERR_SSL_TIMEOUT) return ret;
return nret <= 0 ? nret : nret + ret;
}
~MBTLSSocket()
{
mbedtls_ssl_close_notify(&ssl);
mbedtls_x509_crt_free(&cacert);
mbedtls_entropy_free(&entropy);
mbedtls_ssl_config_free(&conf);
mbedtls_ctr_drbg_free(&entropySource);
mbedtls_ssl_free(&ssl);
}
};
#endif
struct MQTTv5::Impl
{
/** The multithread protection for this object */
Lock lock;
/** This client socket */
BaseSocket * socket;
/** The DER encoded certificate (if provided) */
const DynamicBinDataView * brokerCert;
/** This client unique identifier */
DynamicString clientID;
/** The message received callback to use */
MessageReceived * cb;
/** The default timeout in milliseconds */
struct timeval timeoutMs;
/** The last communication time in second */
uint32 lastCommunication;
/** The publish current default identifier allocator */
uint16 publishCurrentId;
/** The keep alive delay in seconds */
uint16 keepAlive;
#if MQTTUseAuth == 1
/** Mask used to track the origin of the AUTH exchange and reentrancy issues */
uint32 authSource;
#endif
#if MQTTUseUnsubscribe == 1
/** The last unsubscribe id */
uint16 unsubscribeId;
/** The last unsubscribe error code */
MQTTv5::ErrorType::Type lastUnsubscribeError;
#endif
/** The reading state. Because data on a TCP stream is
a stream, we have to remember what state we are currently following while parsing data */
enum RecvState
{
Ready = 0,
GotType,
GotLength,
GotCompletePacket,
} recvState;
/** The receiving buffer size */
uint32 recvBufferSize;
/** The maximum packet size the server is willing to accept */
uint32 maxPacketSize;
/** The available data in the buffer */
uint32 available;
/** The receiving data buffer */
uint8 * recvBuffer;
/** The receiving VBInt size for the packet header */
uint8 packetExpectedVBSize;
uint16 allocatePacketID()
{
return ++publishCurrentId;
}
Impl(const char * clientID, MessageReceived * callback, const DynamicBinDataView * brokerCert)
: socket(0), brokerCert(brokerCert), clientID(clientID), cb(callback), timeoutMs({3, 0}), lastCommunication(0), publishCurrentId(0), keepAlive(300),
#if MQTTUseAuth == 1
authSource(0),
#endif
#if MQTTUseUnsubscribe == 1
unsubscribeId(0), lastUnsubscribeError(ErrorType::WaitingForResult),
#endif
recvState(Ready), recvBufferSize(max(callback->maxPacketSize(), 8U)), maxPacketSize(65535), available(0), recvBuffer((uint8*)::malloc(recvBufferSize)), packetExpectedVBSize(Protocol::MQTT::Common::VBInt(recvBufferSize).getSize())
{}
~Impl() { delete0(socket); ::free(recvBuffer); recvBuffer = 0; recvBufferSize = 0; }
inline void setTimeout(uint32 timeout)
{
timeoutMs.tv_sec = (uint32)timeout / 1024; // Avoid division here (compiler should shift the value here), the value is approximative anyway
timeoutMs.tv_usec = ((uint32)timeout & 1023) * 977; // Avoid modulo here and make sure it doesn't overflow (since 1023 * 977 < 1000000)
}
bool shouldPing()
{
return (((uint32)time(NULL) - lastCommunication) >= keepAlive);
}
bool hasValidLength() const
{
Protocol::MQTT::Common::VBInt l;
return l.readFrom(recvBuffer + 1, available - 1) != Protocol::MQTT::Common::BadData;
}
/** Receive a control packet from the socket in the given time.
@retval positive The number of bytes received
@retval 0 Protocol error, you should close the socket
@retval -1 Socket error
@retval -2 Timeout */
int receiveControlPacket(const bool lowLatency = false)
{
if (!socket) return -1;
// Depending on the current state, we need to fetch as many bytes as possible within the given timeoutMs
// This is a complex problem here because we want both to optimize for
// - latency (returns as fast as possible when we've received a complete packet)
// - blocking time (don't return immediately if the data is currently in transfer, need to wait for it to arrive)
// - minimal syscalls (don't call recv byte per byte as the overhead will be significant)
// - network queue (don't fetch more byte than necessary for getting a single control packet)
// - streaming usage (this can be called while a control packet was being received and we timed out)
// So the algorithm used here depends on the current receiving state
// If we haven't received packet length yet, we have to fetch the header very carefully
// Else, we can enter a more general receiving loop until we have all bytes from the control packet
int ret = 0;
Protocol::MQTT::Common::VBInt len;
#if MQTTLowLatency == 1
// In low latency mode, return as early as possible
if (lowLatency && !socket->select(true, false, true)) return -2;
#endif
// We want to keep track of complete timeout time over multiple operations
switch (recvState)
{
case Ready:
case GotType:
{ // Here, make sure we only fetch the length first
// The minimal size is 2 bytes for PINGRESP and shortcut DISCONNECT / AUTH.
// Because of this, we can't really outsmart the system everytime
ret = socket->recv((char*)&recvBuffer[available], 2 - available);
if (ret > 0) available += ret;
// Deal with timeout first
if (ret < 0 || available < 2)
return (errno == EWOULDBLOCK) ? -2 : -1;
// Depending on the packet type, let's wait for more data
if (recvBuffer[0] < 0xD0 || recvBuffer[1]) // Below ping response or packet size larger than 2 bytes
{
int querySize = (packetExpectedVBSize + 1) - available;
ret = socket->recv((char*)&recvBuffer[available], querySize);
if (ret > 0) available += ret;
// Deal with timeout first
if (ret < 0) return (errno == EWOULDBLOCK) ? -2 : -1;
}
recvState = GotLength;
break;
}
default: break;
}
// Here we should either have a valid control packet header
uint32 r = len.readFrom(&recvBuffer[1], available - 1);
if (r == Protocol::MQTT::Common::BadData)
return 0; // Close the socket here, the given data are wrong or not the right protocol
if (r == Protocol::MQTT::Common::NotEnoughData)
{
if (available >= (packetExpectedVBSize+1))
{ // The server sends us a packet that's larger than the expected maximum size,
// In MQTTv5 it's a protocol error, so let's disconnect
return 0;
}
// We haven't received enough data in the given timeout to make progress, let's report a timeout
recvState = GotType;
return -2;
}
uint32 remainingLength = len;
uint32 totalPacketSize = remainingLength + 1 + len.getSize();
ret = totalPacketSize == available ? 0 : socket->recv((char*)&recvBuffer[available], totalPacketSize - available);
if (ret > 0) available += ret;
if (ret < 0) return (errno == EWOULDBLOCK) ? -2 : -1;
// Ok, let's check if we have received the complete packet
if (available == totalPacketSize)
{
recvState = GotCompletePacket;
#if MQTTDumpCommunication == 1
dumpBufferAsPacket("< Received packet", recvBuffer, available);
#endif
lastCommunication = (uint32)time(NULL);
return (int)available;
}
// No yet, but we probably timed-out.
return -2;
}
/** Get the last received packet type */
Protocol::MQTT::V5::ControlPacketType getLastPacketType() const
{
if (recvState != GotCompletePacket) return Protocol::MQTT::V5::RESERVED;
Protocol::MQTT::V5::FixedHeader header;
header.raw = recvBuffer[0];
return (Protocol::MQTT::V5::ControlPacketType)(uint8)header.type;
}
/** Extract a control packet of the given type */
int extractControlPacket(const Protocol::MQTT::V5::ControlPacketType type, Protocol::MQTT::Common::Serializable & packet)
{
if (recvState != GotCompletePacket)
{
int ret = receiveControlPacket();
if (ret <= 0) return ret;
if (recvState != GotCompletePacket)
return -2;
}
// Check the packet is the last expected type
if (getLastPacketType() != type) return -3;
// Seems to be the expected type, let's unserialize it
uint32 r = packet.readFrom(recvBuffer, recvBufferSize);
if (Protocol::MQTT::Common::isError(r)) return -4; // Parsing error
// Done with receiving the packet let's remember it
resetPacketReceivingState();
#if MQTTDumpCommunication == 1
// String out;
// packet.dump(out, 2);
// printf("Received\n%s\n", (const char*)out);
#endif
return (int)r;
}
void resetPacketReceivingState() { recvState = Ready; available = 0; }
void close()
{