File content as of revision 38:7631b92cc772:

// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

#include <stdlib.h>
#include <string.h>

#include "azure_c_shared_utility/optimize_size.h"
#include "azure_c_shared_utility/gballoc.h"
#include "azure_c_shared_utility/xio.h"
#include "azure_c_shared_utility/xlogging.h"
#include "azure_c_shared_utility/tickcounter.h"

#include "azure_uamqp_c/connection.h"
#include "azure_uamqp_c/frame_codec.h"
#include "azure_uamqp_c/amqp_frame_codec.h"
#include "azure_uamqp_c/amqp_definitions.h"
#include "azure_uamqp_c/amqpvalue_to_string.h"

/* Requirements satisfied by the virtue of implementing the ISO:*/
/* Codes_SRS_CONNECTION_01_088: [Any data appearing beyond the protocol header MUST match the version indicated by the protocol header.] */
/* Codes_SRS_CONNECTION_01_015: [Implementations SHOULD NOT expect to be able to reuse open TCP sockets after close performatives have been exchanged.] */

/* Codes_SRS_CONNECTION_01_087: [The protocol header consists of the upper case ASCII letters "AMQP" followed by a protocol id of zero, followed by three unsigned bytes representing the major, minor, and revision of the protocol version (currently 1 (MAJOR), 0 (MINOR), 0 (REVISION)). In total this is an 8-octet sequence] */
static const unsigned char amqp_header[] = { 'A', 'M', 'Q', 'P', 0, 1, 0, 0 };

typedef enum RECEIVE_FRAME_STATE_TAG
{
    RECEIVE_FRAME_STATE_FRAME_SIZE,
    RECEIVE_FRAME_STATE_FRAME_DATA
} RECEIVE_FRAME_STATE;

typedef struct ENDPOINT_INSTANCE_TAG
{
    uint16_t incoming_channel;
    uint16_t outgoing_channel;
    ON_ENDPOINT_FRAME_RECEIVED on_endpoint_frame_received;
    ON_CONNECTION_STATE_CHANGED on_connection_state_changed;
    void* callback_context;
    CONNECTION_HANDLE connection;
} ENDPOINT_INSTANCE;

typedef struct CONNECTION_INSTANCE_TAG
{
    XIO_HANDLE io;
    size_t header_bytes_received;
    CONNECTION_STATE connection_state;
    FRAME_CODEC_HANDLE frame_codec;
    AMQP_FRAME_CODEC_HANDLE amqp_frame_codec;
    ENDPOINT_INSTANCE** endpoints;
    uint32_t endpoint_count;
    char* host_name;
    char* container_id;
    TICK_COUNTER_HANDLE tick_counter;
    uint32_t remote_max_frame_size;

    ON_SEND_COMPLETE on_send_complete;
    void* on_send_complete_callback_context;

    ON_NEW_ENDPOINT on_new_endpoint;
    void* on_new_endpoint_callback_context;

    ON_CONNECTION_STATE_CHANGED on_connection_state_changed;
    void* on_connection_state_changed_callback_context;
    ON_IO_ERROR on_io_error;
    void* on_io_error_callback_context;

    /* options */
    uint32_t max_frame_size;
    uint16_t channel_max;
    milliseconds idle_timeout;
    milliseconds remote_idle_timeout;
    milliseconds remote_idle_timeout_send_frame_millisecond;
    double idle_timeout_empty_frame_send_ratio;
    tickcounter_ms_t last_frame_received_time;
    tickcounter_ms_t last_frame_sent_time;

    unsigned int is_underlying_io_open : 1;
    unsigned int idle_timeout_specified : 1;
    unsigned int is_remote_frame_received : 1;
    unsigned int is_trace_on : 1;
} CONNECTION_INSTANCE;

/* Codes_SRS_CONNECTION_01_258: [on_connection_state_changed shall be invoked whenever the connection state changes.]*/
static void connection_set_state(CONNECTION_HANDLE connection, CONNECTION_STATE connection_state)
{
    uint64_t i;

    CONNECTION_STATE previous_state = connection->connection_state;
    connection->connection_state = connection_state;

    /* Codes_SRS_CONNECTION_22_001: [If a connection state changed occurs and a callback is registered the callback shall be called.] */
    if (connection->on_connection_state_changed)
    {
        connection->on_connection_state_changed(connection->on_connection_state_changed_callback_context, connection_state, previous_state);
    }

    /* Codes_SRS_CONNECTION_01_260: [Each endpoint's on_connection_state_changed shall be called.] */
    for (i = 0; i < connection->endpoint_count; i++)
    {
        /* Codes_SRS_CONNECTION_01_259: [The callback_context passed in connection_create_endpoint.] */
        connection->endpoints[i]->on_connection_state_changed(connection->endpoints[i]->callback_context, connection_state, previous_state);
    }
}

// This callback usage needs to be either verified and commented or integrated into 
// the state machine.
static void unchecked_on_send_complete(void* context, IO_SEND_RESULT send_result)
{
    (void)context;
    (void)send_result;
}

static int send_header(CONNECTION_HANDLE connection)
{
    int result;

    /* Codes_SRS_CONNECTION_01_093: [_ When the client opens a new socket connection to a server, it MUST send a protocol header with the client's preferred protocol version.] */
    /* Codes_SRS_CONNECTION_01_104: [Sending the protocol header shall be done by using xio_send.] */
    if (xio_send(connection->io, amqp_header, sizeof(amqp_header), unchecked_on_send_complete, NULL) != 0)
    {
        /* Codes_SRS_CONNECTION_01_106: [When sending the protocol header fails, the connection shall be immediately closed.] */
        if (xio_close(connection->io, NULL, NULL) != 0)
        {
            LogError("xio_close failed");
        }

        /* Codes_SRS_CONNECTION_01_057: [END In this state it is illegal for either endpoint to write anything more onto the connection. The connection can be safely closed and discarded.] */
        connection_set_state(connection, CONNECTION_STATE_END);

        /* Codes_SRS_CONNECTION_01_105: [When xio_send fails, connection_dowork shall return a non-zero value.] */
        result = __FAILURE__;
    }
    else
    {
        if (connection->is_trace_on == 1)
        {
            LOG(AZ_LOG_TRACE, LOG_LINE, "-> Header (AMQP 0.1.0.0)");
        }

        /* Codes_SRS_CONNECTION_01_041: [HDR SENT In this state the connection header has been sent to the peer but no connection header has been received.] */
        connection_set_state(connection, CONNECTION_STATE_HDR_SENT);
        result = 0;
    }

    return result;
}

static const char* get_frame_type_as_string(AMQP_VALUE descriptor)
{
    const char* result;

    if (is_open_type_by_descriptor(descriptor))
    {
        result = "[OPEN]";
    }
    else if (is_begin_type_by_descriptor(descriptor))
    {
        result = "[BEGIN]";
    }
    else if (is_attach_type_by_descriptor(descriptor))
    {
        result = "[ATTACH]";
    }
    else if (is_flow_type_by_descriptor(descriptor))
    {
        result = "[FLOW]";
    }
    else if (is_disposition_type_by_descriptor(descriptor))
    {
        result = "[DISPOSITION]";
    }
    else if (is_transfer_type_by_descriptor(descriptor))
    {
        result = "[TRANSFER]";
    }
    else if (is_detach_type_by_descriptor(descriptor))
    {
        result = "[DETACH]";
    }
    else if (is_end_type_by_descriptor(descriptor))
    {
        result = "[END]";
    }
    else if (is_close_type_by_descriptor(descriptor))
    {
        result = "[CLOSE]";
    }
    else
    {
        result = "[Unknown]";
    }

    return result;
}

static void log_incoming_frame(AMQP_VALUE performative)
{
#ifdef NO_LOGGING
    UNUSED(performative);
#else
    AMQP_VALUE descriptor = amqpvalue_get_inplace_descriptor(performative);
    if (descriptor == NULL)
    {
        LogError("Error getting performative descriptor");
    }
    else
    {
        char* performative_as_string;
        LOG(AZ_LOG_TRACE, 0, "<- ");
        LOG(AZ_LOG_TRACE, 0, (char*)get_frame_type_as_string(descriptor));
        performative_as_string = NULL;
        LOG(AZ_LOG_TRACE, LOG_LINE, (performative_as_string = amqpvalue_to_string(performative)));
        if (performative_as_string != NULL)
        {
            free(performative_as_string);
        }
    }
#endif
}

static void log_outgoing_frame(AMQP_VALUE performative)
{
#ifdef NO_LOGGING
    UNUSED(performative);
#else
    AMQP_VALUE descriptor = amqpvalue_get_inplace_descriptor(performative);
    if (descriptor == NULL)
    {
        LogError("Error getting performative descriptor");
    }
    else
    {
        char* performative_as_string;
        LOG(AZ_LOG_TRACE, 0, "-> ");
        LOG(AZ_LOG_TRACE, 0, (char*)get_frame_type_as_string(descriptor));
        performative_as_string = NULL;
        LOG(AZ_LOG_TRACE, LOG_LINE, (performative_as_string = amqpvalue_to_string(performative)));
        if (performative_as_string != NULL)
        {
            free(performative_as_string);
        }
    }
#endif
}

static void on_bytes_encoded(void* context, const unsigned char* bytes, size_t length, bool encode_complete)
{
    CONNECTION_HANDLE connection = (CONNECTION_HANDLE)context;
    if (xio_send(connection->io, bytes, length, 
        (encode_complete && connection->on_send_complete != NULL) ? connection->on_send_complete : unchecked_on_send_complete,
        connection->on_send_complete_callback_context) != 0)
    {
        LogError("Cannot send encoded bytes");

        if (xio_close(connection->io, NULL, NULL) != 0)
        {
            LogError("xio_close failed");
        }

        connection_set_state(connection, CONNECTION_STATE_END);
    }
}

static int send_open_frame(CONNECTION_HANDLE connection)
{
    int result;

    /* Codes_SRS_CONNECTION_01_151: [The connection max_frame_size setting shall be passed down to the frame_codec when the Open frame is sent.] */
    if (frame_codec_set_max_frame_size(connection->frame_codec, connection->max_frame_size) != 0)
    {
        LogError("Cannot set max frame size");

        /* Codes_SRS_CONNECTION_01_207: [If frame_codec_set_max_frame_size fails the connection shall be closed and the state set to END.] */
        if (xio_close(connection->io, NULL, NULL) != 0)
        {
            LogError("xio_close failed");
        }

        connection_set_state(connection, CONNECTION_STATE_END);
        result = __FAILURE__;
    }
    else
    {
        /* Codes_SRS_CONNECTION_01_134: [The container id field shall be filled with the container id specified in connection_create.] */
        OPEN_HANDLE open_performative = open_create(connection->container_id);
        if (open_performative == NULL)
        {
            LogError("Cannot create OPEN performative");
            
            /* Codes_SRS_CONNECTION_01_208: [If the open frame cannot be constructed, the connection shall be closed and set to the END state.] */
            if (xio_close(connection->io, NULL, NULL) != 0)
            {
                LogError("xio_close failed");
            }

            connection_set_state(connection, CONNECTION_STATE_END);
            result = __FAILURE__;
        }
        else
        {
            /* Codes_SRS_CONNECTION_01_137: [The max_frame_size connection setting shall be set in the open frame by using open_set_max_frame_size.] */
            if (open_set_max_frame_size(open_performative, connection->max_frame_size) != 0)
            {
                LogError("Cannot set max frame size");

                /* Codes_SRS_CONNECTION_01_208: [If the open frame cannot be constructed, the connection shall be closed and set to the END state.] */
                if (xio_close(connection->io, NULL, NULL) != 0)
                {
                    LogError("xio_close failed");
                }

                connection_set_state(connection, CONNECTION_STATE_END);
                result = __FAILURE__;
            }
            /* Codes_SRS_CONNECTION_01_139: [The channel_max connection setting shall be set in the open frame by using open_set_channel_max.] */
            else if (open_set_channel_max(open_performative, connection->channel_max) != 0)
            {
                LogError("Cannot set max channel");

                /* Codes_SRS_CONNECTION_01_208: [If the open frame cannot be constructed, the connection shall be closed and set to the END state.] */
                if (xio_close(connection->io, NULL, NULL) != 0)
                {
                    LogError("xio_close failed");
                }

                connection_set_state(connection, CONNECTION_STATE_END);
                result = __FAILURE__;
            }
            /* Codes_SRS_CONNECTION_01_142: [If no idle_timeout value has been specified, no value shall be stamped in the open frame (no call to open_set_idle_time_out shall be made).] */
            else if ((connection->idle_timeout_specified) &&
                /* Codes_SRS_CONNECTION_01_141: [If idle_timeout has been specified by a call to connection_set_idle_timeout, then that value shall be stamped in the open frame.] */
                (open_set_idle_time_out(open_performative, connection->idle_timeout) != 0))
            {
                /* Codes_SRS_CONNECTION_01_208: [If the open frame cannot be constructed, the connection shall be closed and set to the END state.] */
                if (xio_close(connection->io, NULL, NULL) != 0)
                {
                    LogError("xio_close failed");
                }

                connection_set_state(connection, CONNECTION_STATE_END);
                result = __FAILURE__;
            }
            /* Codes_SRS_CONNECTION_01_136: [If no hostname value has been specified, no value shall be stamped in the open frame (no call to open_set_hostname shall be made).] */
            else if ((connection->host_name != NULL) &&
                /* Codes_SRS_CONNECTION_01_135: [If hostname has been specified by a call to connection_set_hostname, then that value shall be stamped in the open frame.] */
                (open_set_hostname(open_performative, connection->host_name) != 0))
            {
                LogError("Cannot set hostname");

                /* Codes_SRS_CONNECTION_01_208: [If the open frame cannot be constructed, the connection shall be closed and set to the END state.] */
                if (xio_close(connection->io, NULL, NULL) != 0)
                {
                    LogError("xio_close failed");
                }

                connection_set_state(connection, CONNECTION_STATE_END);
                result = __FAILURE__;
            }
            else
            {
                AMQP_VALUE open_performative_value = amqpvalue_create_open(open_performative);
                if (open_performative_value == NULL)
                {
                    LogError("Cannot create OPEN AMQP value");

                    /* Codes_SRS_CONNECTION_01_208: [If the open frame cannot be constructed, the connection shall be closed and set to the END state.] */
                    if (xio_close(connection->io, NULL, NULL) != 0)
                    {
                        LogError("xio_close failed");
                    }

                    connection_set_state(connection, CONNECTION_STATE_END);
                    result = __FAILURE__;
                }
                else
                {
                    /* Codes_SRS_CONNECTION_01_002: [Each AMQP connection begins with an exchange of capabilities and limitations, including the maximum frame size.] */
                    /* Codes_SRS_CONNECTION_01_004: [After establishing or accepting a TCP connection and sending the protocol header, each peer MUST send an open frame before sending any other frames.] */
                    /* Codes_SRS_CONNECTION_01_005: [The open frame describes the capabilities and limits of that peer.] */
                    /* Codes_SRS_CONNECTION_01_205: [Sending the AMQP OPEN frame shall be done by calling amqp_frame_codec_begin_encode_frame with channel number 0, the actual performative payload and 0 as payload_size.] */
                    /* Codes_SRS_CONNECTION_01_006: [The open frame can only be sent on channel 0.] */
                    connection->on_send_complete = NULL;
                    connection->on_send_complete_callback_context = NULL;
                    if (amqp_frame_codec_encode_frame(connection->amqp_frame_codec, 0, open_performative_value, NULL, 0, on_bytes_encoded, connection) != 0)
                    {
                        LogError("amqp_frame_codec_encode_frame failed");

                        /* Codes_SRS_CONNECTION_01_206: [If sending the frame fails, the connection shall be closed and state set to END.] */
                        if (xio_close(connection->io, NULL, NULL) != 0)
                        {
                            LogError("xio_close failed");
                        }

                        connection_set_state(connection, CONNECTION_STATE_END);
                        result = __FAILURE__;
                    }
                    else
                    {
                        if (connection->is_trace_on == 1)
                        {
                            log_outgoing_frame(open_performative_value);
                        }

                        /* Codes_SRS_CONNECTION_01_046: [OPEN SENT In this state the connection headers have been exchanged. An open frame has been sent to the peer but no open frame has yet been received.] */
                        connection_set_state(connection, CONNECTION_STATE_OPEN_SENT);
                        result = 0;
                    }

                    amqpvalue_destroy(open_performative_value);
                }
            }

            open_destroy(open_performative);
        }
    }

    return result;
}

static int send_close_frame(CONNECTION_HANDLE connection, ERROR_HANDLE error_handle)
{
    int result;
    CLOSE_HANDLE close_performative;

    /* Codes_SRS_CONNECTION_01_217: [The CLOSE frame shall be constructed by using close_create.] */
    close_performative = close_create();
    if (close_performative == NULL)
    {
        LogError("Cannot create close performative");
        result = __FAILURE__;
    }
    else
    {
        if ((error_handle != NULL) &&
            /* Codes_SRS_CONNECTION_01_238: [If set, this field indicates that the connection is being closed due to an error condition.] */
            (close_set_error(close_performative, error_handle) != 0))
        {
            LogError("Cannot set error on CLOSE");
            result = __FAILURE__;
        }
        else
        {
            AMQP_VALUE close_performative_value = amqpvalue_create_close(close_performative);
            if (close_performative_value == NULL)
            {
                LogError("Cannot create AMQP CLOSE performative value");
                result = __FAILURE__;
            }
            else
            {
                /* Codes_SRS_CONNECTION_01_215: [Sending the AMQP CLOSE frame shall be done by calling amqp_frame_codec_begin_encode_frame with channel number 0, the actual performative payload and 0 as payload_size.] */
                /* Codes_SRS_CONNECTION_01_013: [However, implementations SHOULD send it on channel 0] */
                connection->on_send_complete = NULL;
                connection->on_send_complete_callback_context = NULL;
                if (amqp_frame_codec_encode_frame(connection->amqp_frame_codec, 0, close_performative_value, NULL, 0, on_bytes_encoded, connection) != 0)
                {
                    LogError("amqp_frame_codec_encode_frame failed");
                    result = __FAILURE__;
                }
                else
                {
                    if (connection->is_trace_on == 1)
                    {
                        log_outgoing_frame(close_performative_value);
                    }

                    result = 0;
                }

                amqpvalue_destroy(close_performative_value);
            }
        }

        close_destroy(close_performative);
    }

    return result;
}

static void close_connection_with_error(CONNECTION_HANDLE connection, const char* condition_value, const char* description)
{
    ERROR_HANDLE error_handle = error_create(condition_value);
    if (error_handle == NULL)
    {
        /* Codes_SRS_CONNECTION_01_214: [If the close frame cannot be constructed or sent, the connection shall be closed and set to the END state.] */
        if (xio_close(connection->io, NULL, NULL) != 0)
        {
            LogError("xio_close failed");
        }

        connection_set_state(connection, CONNECTION_STATE_END);
    }
    else
    {
        /* Codes_SRS_CONNECTION_01_219: [The error description shall be set to an implementation defined string.] */
        if (error_set_description(error_handle, description) != 0)
        {
            LogError("Cannot set error description on CLOSE frame");

            /* Codes_SRS_CONNECTION_01_214: [If the close frame cannot be constructed or sent, the connection shall be closed and set to the END state.] */
            if (xio_close(connection->io, NULL, NULL) != 0)
            {
                LogError("xio_close failed");
            }

            connection_set_state(connection, CONNECTION_STATE_END);
        }
        else if (send_close_frame(connection, error_handle) != 0)
        {
            LogError("Cannot send CLOSE frame");

            /* Codes_SRS_CONNECTION_01_214: [If the close frame cannot be constructed or sent, the connection shall be closed and set to the END state.] */
            if (xio_close(connection->io, NULL, NULL) != 0)
            {
                LogError("xio_close failed");
            }

            connection_set_state(connection, CONNECTION_STATE_END);
        }
        else
        {
            /* Codes_SRS_CONNECTION_01_213: [When passing the bytes to frame_codec fails, a CLOSE frame shall be sent and the state shall be set to DISCARDING.] */
            /* Codes_SRS_CONNECTION_01_055: [DISCARDING The DISCARDING state is a variant of the CLOSE SENT state where the close is triggered by an error.] */
            /* Codes_SRS_CONNECTION_01_010: [After writing this frame the peer SHOULD continue to read from the connection until it receives the partner's close frame ] */
            connection_set_state(connection, CONNECTION_STATE_DISCARDING);
        }

        error_destroy(error_handle);
    }
}

static ENDPOINT_INSTANCE* find_session_endpoint_by_outgoing_channel(CONNECTION_HANDLE connection, uint16_t outgoing_channel)
{
    uint32_t i;
    ENDPOINT_INSTANCE* result;

    for (i = 0; i < connection->endpoint_count; i++)
    {
        if (connection->endpoints[i]->outgoing_channel == outgoing_channel)
        {
            break;
        }
    }

    if (i == connection->endpoint_count)
    {
        LogError("Cannot find session endpoint for channel %u", (unsigned int)outgoing_channel);
        result = NULL;
    }
    else
    {
        result = connection->endpoints[i];
    }

    return result;
}

static ENDPOINT_INSTANCE* find_session_endpoint_by_incoming_channel(CONNECTION_HANDLE connection, uint16_t incoming_channel)
{
    uint32_t i;
    ENDPOINT_INSTANCE* result;

    for (i = 0; i < connection->endpoint_count; i++)
    {
        if (connection->endpoints[i]->incoming_channel == incoming_channel)
        {
            break;
        }
    }

    if (i == connection->endpoint_count)
    {
        LogError("Cannot find session endpoint for channel %u", (unsigned int)incoming_channel);
        result = NULL;
    }
    else
    {
        result = connection->endpoints[i];
    }

    return result;
}

static int connection_byte_received(CONNECTION_HANDLE connection, unsigned char b)
{
    int result;

    switch (connection->connection_state)
    {
    default:
        LogError("Unknown connection state: %d", (int)connection->connection_state);
        result = __FAILURE__;
        break;

    /* Codes_SRS_CONNECTION_01_039: [START In this state a connection exists, but nothing has been sent or received. This is the state an implementation would be in immediately after performing a socket connect or socket accept.] */
    case CONNECTION_STATE_START:

    /* Codes_SRS_CONNECTION_01_041: [HDR SENT In this state the connection header has been sent to the peer but no connection header has been received.] */
    case CONNECTION_STATE_HDR_SENT:
        if (b != amqp_header[connection->header_bytes_received])
        {
            /* Codes_SRS_CONNECTION_01_089: [If the incoming and outgoing protocol headers do not match, both peers MUST close their outgoing stream] */
            if (xio_close(connection->io, NULL, NULL) != 0)
            {
                LogError("xio_close failed");
            }

            connection_set_state(connection, CONNECTION_STATE_END);
            result = __FAILURE__;
        }
        else
        {
            connection->header_bytes_received++;
            if (connection->header_bytes_received == sizeof(amqp_header))
            {
                if (connection->is_trace_on == 1)
                {
                    LOG(AZ_LOG_TRACE, LOG_LINE, "<- Header (AMQP 0.1.0.0)");
                }

                connection_set_state(connection, CONNECTION_STATE_HDR_EXCH);

                if (send_open_frame(connection) != 0)
                {
                    LogError("Cannot send open frame");
                    connection_set_state(connection, CONNECTION_STATE_END);
                }
            }

            result = 0;
        }
        break;

    /* Codes_SRS_CONNECTION_01_040: [HDR RCVD In this state the connection header has been received from the peer but a connection header has not been sent.] */
    case CONNECTION_STATE_HDR_RCVD:

    /* Codes_SRS_CONNECTION_01_042: [HDR EXCH In this state the connection header has been sent to the peer and a connection header has been received from the peer.] */
    /* we should not really get into this state, but just in case, we would treat that in the same way as HDR_RCVD */
    case CONNECTION_STATE_HDR_EXCH:

    /* Codes_SRS_CONNECTION_01_045: [OPEN RCVD In this state the connection headers have been exchanged. An open frame has been received from the peer but an open frame has not been sent.] */
    case CONNECTION_STATE_OPEN_RCVD:

    /* Codes_SRS_CONNECTION_01_046: [OPEN SENT In this state the connection headers have been exchanged. An open frame has been sent to the peer but no open frame has yet been received.] */
    case CONNECTION_STATE_OPEN_SENT:

    /* Codes_SRS_CONNECTION_01_048: [OPENED In this state the connection header and the open frame have been both sent and received.] */
    case CONNECTION_STATE_OPENED:
        /* Codes_SRS_CONNECTION_01_212: [After the initial handshake has been done all bytes received from the io instance shall be passed to the frame_codec for decoding by calling frame_codec_receive_bytes.] */
        if (frame_codec_receive_bytes(connection->frame_codec, &b, 1) != 0)
        {
            LogError("Cannot process received bytes");
            /* Codes_SRS_CONNECTION_01_218: [The error amqp:internal-error shall be set in the error.condition field of the CLOSE frame.] */
            /* Codes_SRS_CONNECTION_01_219: [The error description shall be set to an implementation defined string.] */
            close_connection_with_error(connection, "amqp:internal-error", "connection_byte_received::frame_codec_receive_bytes failed");
            result = __FAILURE__;
        }
        else
        {
            result = 0;
        }

        break;
    }

    return result;
}

static void connection_on_bytes_received(void* context, const unsigned char* buffer, size_t size)
{
    size_t i;

    for (i = 0; i < size; i++)
    {
        if (connection_byte_received((CONNECTION_HANDLE)context, buffer[i]) != 0)
        {
            LogError("Cannot process received bytes");
            break;
        }
    }
}

static void connection_on_io_open_complete(void* context, IO_OPEN_RESULT io_open_result)
{
    CONNECTION_HANDLE connection = (CONNECTION_HANDLE)context;

    if (io_open_result == IO_OPEN_OK)
    {
        /* Codes_SRS_CONNECTION_01_084: [The connection_instance state machine implementing the protocol requirements shall be run as part of connection_dowork.] */
        switch (connection->connection_state)
        {
        default:
            LogError("Unknown connection state: %d", (int)connection->connection_state);
            break;

        case CONNECTION_STATE_START:
            /* Codes_SRS_CONNECTION_01_086: [Prior to sending any frames on a connection_instance, each peer MUST start by sending a protocol header that indicates the protocol version used on the connection_instance.] */
            /* Codes_SRS_CONNECTION_01_091: [The AMQP peer which acted in the role of the TCP client (i.e. the peer that actively opened the connection_instance) MUST immediately send its outgoing protocol header on establishment of the TCP connection_instance.] */
            if (send_header(connection) != 0)
            {
                LogError("Cannot send header");
            }
            break;

        case CONNECTION_STATE_HDR_SENT:
        case CONNECTION_STATE_OPEN_SENT:
        case CONNECTION_STATE_OPENED:
            break;

        case CONNECTION_STATE_HDR_EXCH:
            /* Codes_SRS_CONNECTION_01_002: [Each AMQP connection_instance begins with an exchange of capabilities and limitations, including the maximum frame size.] */
            /* Codes_SRS_CONNECTION_01_004: [After establishing or accepting a TCP connection_instance and sending the protocol header, each peer MUST send an open frame before sending any other frames.] */
            /* Codes_SRS_CONNECTION_01_005: [The open frame describes the capabilities and limits of that peer.] */
            if (send_open_frame(connection) != 0)
            {
                LogError("Cannot send OPEN frame");
                connection_set_state(connection, CONNECTION_STATE_END);
            }
            break;

        case CONNECTION_STATE_OPEN_RCVD:
            break;
        }
    }
    else
    {
        connection_set_state(connection, CONNECTION_STATE_END);
    }
}

static void connection_on_io_error(void* context)
{
    CONNECTION_HANDLE connection = (CONNECTION_HANDLE)context;

    /* Codes_SRS_CONNECTION_22_005: [If the io notifies the connection instance of an IO_STATE_ERROR state and an io error callback is registered, the connection shall call the registered callback.] */
    if (connection->on_io_error)
    {
        connection->on_io_error(connection->on_io_error_callback_context);
    }

    if (connection->connection_state != CONNECTION_STATE_END)
    {
        /* Codes_SRS_CONNECTION_01_202: [If the io notifies the connection instance of an IO_STATE_ERROR state the connection shall be closed and the state set to END.] */
        connection_set_state(connection, CONNECTION_STATE_ERROR);
        if (xio_close(connection->io, NULL, NULL) != 0)
        {
            LogError("xio_close failed");
        }
    }
}

static void on_empty_amqp_frame_received(void* context, uint16_t channel)
{
    CONNECTION_HANDLE connection = (CONNECTION_HANDLE)context;
    /* It does not matter on which channel we received the frame */
    (void)channel;

    if (connection->is_trace_on == 1)
    {
        LOG(AZ_LOG_TRACE, LOG_LINE, "<- Empty frame");
    }
    if (tickcounter_get_current_ms(connection->tick_counter, &connection->last_frame_received_time) != 0)
    {
        LogError("Cannot get tickcounter value");
    }
}

static void on_amqp_frame_received(void* context, uint16_t channel, AMQP_VALUE performative, const unsigned char* payload_bytes, uint32_t payload_size)
{
    CONNECTION_HANDLE connection = (CONNECTION_HANDLE)context;

    (void)channel;

    if (tickcounter_get_current_ms(connection->tick_counter, &connection->last_frame_received_time) != 0)
    {
        LogError("Cannot get tickcounter value");
        close_connection_with_error(connection, "amqp:internal-error", "cannot get current tick count");
    }
    else
    {
        if (connection->is_underlying_io_open)
        {
            switch (connection->connection_state)
            {
            default:
                if (performative == NULL)
                {
                    /* Codes_SRS_CONNECTION_01_223: [If the on_endpoint_frame_received is called with a NULL performative then the connection shall be closed with the error condition amqp:internal-error and an implementation defined error description.] */
                    close_connection_with_error(connection, "amqp:internal-error", "connection_endpoint_frame_received::NULL performative");
                    LogError("connection_endpoint_frame_received::NULL performative");
                }
                else
                {
                    AMQP_VALUE descriptor = amqpvalue_get_inplace_descriptor(performative);
                    uint64_t performative_ulong;

                    if (connection->is_trace_on == 1)
                    {
                        log_incoming_frame(performative);
                    }

                    if (is_open_type_by_descriptor(descriptor))
                    {
                        if (channel != 0)
                        {
                            /* Codes_SRS_CONNECTION_01_006: [The open frame can only be sent on channel 0.] */
                            /* Codes_SRS_CONNECTION_01_222: [If an Open frame is received in a manner violating the ISO specification, the connection shall be closed with condition amqp:not-allowed and description being an implementation defined string.] */
                            close_connection_with_error(connection, "amqp:not-allowed", "OPEN frame received on a channel that is not 0");
                            LogError("OPEN frame received on a channel that is not 0");
                        }

                        if (connection->connection_state == CONNECTION_STATE_OPENED)
                        {
                            /* Codes_SRS_CONNECTION_01_239: [If an Open frame is received in the Opened state the connection shall be closed with condition amqp:illegal-state and description being an implementation defined string.] */
                            close_connection_with_error(connection, "amqp:illegal-state", "OPEN frame received in the OPENED state");
                            LogError("OPEN frame received in the OPENED state");
                        }
                        else if ((connection->connection_state == CONNECTION_STATE_OPEN_SENT) ||
                            (connection->connection_state == CONNECTION_STATE_HDR_EXCH))
                        {
                            OPEN_HANDLE open_handle;
                            if (amqpvalue_get_open(performative, &open_handle) != 0)
                            {
                                /* Codes_SRS_CONNECTION_01_143: [If any of the values in the received open frame are invalid then the connection shall be closed.] */
                                /* Codes_SRS_CONNECTION_01_220: [The error amqp:invalid-field shall be set in the error.condition field of the CLOSE frame.] */
                                close_connection_with_error(connection, "amqp:invalid-field", "connection_endpoint_frame_received::failed parsing OPEN frame");
                                LogError("connection_endpoint_frame_received::failed parsing OPEN frame");
                            }
                            else
                            {
                                if (open_get_idle_time_out(open_handle, &connection->remote_idle_timeout) == 0)
                                {
                                    /* since we obtained the remote_idle_timeout, compute at what millisecond we should send the empty frame */
                                    connection->remote_idle_timeout_send_frame_millisecond = (milliseconds)(connection->idle_timeout_empty_frame_send_ratio * connection->remote_idle_timeout);
                                }

                                if ((open_get_max_frame_size(open_handle, &connection->remote_max_frame_size) != 0) ||
                                    /* Codes_SRS_CONNECTION_01_167: [Both peers MUST accept frames of up to 512 (MIN-MAX-FRAME-SIZE) octets.] */
                                    (connection->remote_max_frame_size < 512))
                                {
                                    /* Codes_SRS_CONNECTION_01_143: [If any of the values in the received open frame are invalid then the connection shall be closed.] */
                                    /* Codes_SRS_CONNECTION_01_220: [The error amqp:invalid-field shall be set in the error.condition field of the CLOSE frame.] */
                                    close_connection_with_error(connection, "amqp:invalid-field", "connection_endpoint_frame_received::failed parsing OPEN frame");
                                    LogError("connection_endpoint_frame_received::failed parsing OPEN frame");
                                }
                                else
                                {
                                    if (connection->connection_state == CONNECTION_STATE_OPEN_SENT)
                                    {
                                        connection_set_state(connection, CONNECTION_STATE_OPENED);
                                    }
                                    else
                                    {
                                        if (send_open_frame(connection) != 0)
                                        {
                                            connection_set_state(connection, CONNECTION_STATE_END);
                                        }
                                        else
                                        {
                                            connection_set_state(connection, CONNECTION_STATE_OPENED);
                                        }
                                    }
                                }

                                open_destroy(open_handle);
                            }
                        }
                        else
                        {
                            /* do nothing for now ... */
                        }
                    }
                    else if (is_close_type_by_descriptor(descriptor))
                    {
                        /* Codes_SRS_CONNECTION_01_012: [A close frame MAY be received on any channel up to the maximum channel number negotiated in open.] */
                        /* Codes_SRS_CONNECTION_01_242: [The connection module shall accept CLOSE frames even if they have extra payload bytes besides the Close performative.] */

                        /* Codes_SRS_CONNECTION_01_225: [HDR_RCVD HDR OPEN] */
                        if ((connection->connection_state == CONNECTION_STATE_HDR_RCVD) ||
                            /* Codes_SRS_CONNECTION_01_227: [HDR_EXCH OPEN OPEN] */
                            (connection->connection_state == CONNECTION_STATE_HDR_EXCH) ||
                            /* Codes_SRS_CONNECTION_01_228: [OPEN_RCVD OPEN *] */
                            (connection->connection_state == CONNECTION_STATE_OPEN_RCVD) ||
                            /* Codes_SRS_CONNECTION_01_235: [CLOSE_SENT - * TCP Close for Write] */
                            (connection->connection_state == CONNECTION_STATE_CLOSE_SENT) ||
                            /* Codes_SRS_CONNECTION_01_236: [DISCARDING - * TCP Close for Write] */
                            (connection->connection_state == CONNECTION_STATE_DISCARDING))
                        {
                            if (xio_close(connection->io, NULL, NULL) != 0)
                            {
                                LogError("xio_close failed");
                            }
                        }
                        else
                        {
                            CLOSE_HANDLE close_handle;

                            /* Codes_SRS_CONNECTION_01_012: [A close frame MAY be received on any channel up to the maximum channel number negotiated in open.] */
                            if (channel > connection->channel_max)
                            {
                                close_connection_with_error(connection, "amqp:invalid-field", "connection_endpoint_frame_received::failed parsing CLOSE frame");
                                LogError("connection_endpoint_frame_received::failed parsing CLOSE frame");
                            }
                            else
                            {
                                if (amqpvalue_get_close(performative, &close_handle) != 0)
                                {
                                    close_connection_with_error(connection, "amqp:invalid-field", "connection_endpoint_frame_received::failed parsing CLOSE frame");
                                    LogError("connection_endpoint_frame_received::failed parsing CLOSE frame");
                                }
                                else
                                {
                                    close_destroy(close_handle);

                                    connection_set_state(connection, CONNECTION_STATE_CLOSE_RCVD);

                                    if (send_close_frame(connection, NULL) != 0)
                                    {
                                        LogError("Cannot send CLOSE frame");
                                    }

                                    /* Codes_SRS_CONNECTION_01_214: [If the close frame cannot be constructed or sent, the connection shall be closed and set to the END state.] */
                                    if (xio_close(connection->io, NULL, NULL) != 0)
                                    {
                                        LogError("xio_close failed");
                                    }

                                    connection_set_state(connection, CONNECTION_STATE_END);
                                }
                            }
                        }
                    }
                    else
                    {
                        amqpvalue_get_ulong(descriptor, &performative_ulong);

                        switch (performative_ulong)
                        {
                        default:
                            LogError("Bad performative: %02x", performative);
                            break;

                        case AMQP_BEGIN:
                        {
                            BEGIN_HANDLE begin;

                            if (amqpvalue_get_begin(performative, &begin) != 0)
                            {
                                LogError("Cannot get begin performative");
                            }
                            else
                            {
                                uint16_t remote_channel;
                                ENDPOINT_HANDLE new_endpoint = NULL;
                                bool remote_begin = false;

                                if (begin_get_remote_channel(begin, &remote_channel) != 0)
                                {
                                    remote_begin = true;
                                    if (connection->on_new_endpoint != NULL)
                                    {
                                        new_endpoint = connection_create_endpoint(connection);
                                        if (!connection->on_new_endpoint(connection->on_new_endpoint_callback_context, new_endpoint))
                                        {
                                            connection_destroy_endpoint(new_endpoint);
                                            new_endpoint = NULL;
                                        }
                                    }
                                }

                                if (!remote_begin)
                                {
                                    ENDPOINT_INSTANCE* session_endpoint = find_session_endpoint_by_outgoing_channel(connection, remote_channel);
                                    if (session_endpoint == NULL)
                                    {
                                        LogError("Cannot create session endpoint");
                                    }
                                    else
                                    {
                                        session_endpoint->incoming_channel = channel;
                                        session_endpoint->on_endpoint_frame_received(session_endpoint->callback_context, performative, payload_size, payload_bytes);
                                    }
                                }
                                else
                                {
                                    if (new_endpoint != NULL)
                                    {
                                        new_endpoint->incoming_channel = channel;
                                        new_endpoint->on_endpoint_frame_received(new_endpoint->callback_context, performative, payload_size, payload_bytes);
                                    }
                                }

                                begin_destroy(begin);
                            }

                            break;
                        }

                        case AMQP_FLOW:
                        case AMQP_TRANSFER:
                        case AMQP_DISPOSITION:
                        case AMQP_END:
                        case AMQP_ATTACH:
                        case AMQP_DETACH:
                        {
                            ENDPOINT_INSTANCE* session_endpoint = find_session_endpoint_by_incoming_channel(connection, channel);
                            if (session_endpoint == NULL)
                            {
                                LogError("Cannot find session endpoint for channel %u", (unsigned int)channel);
                            }
                            else
                            {
                                session_endpoint->on_endpoint_frame_received(session_endpoint->callback_context, performative, payload_size, payload_bytes);
                            }

                            break;
                        }
                        }
                    }
                }
                break;

            case CONNECTION_STATE_START:
                /* Codes_SRS_CONNECTION_01_224: [START HDR HDR] */
            case CONNECTION_STATE_HDR_SENT:
                /* Codes_SRS_CONNECTION_01_226: [HDR_SENT OPEN HDR] */
            case CONNECTION_STATE_OPEN_PIPE:
                /* Codes_SRS_CONNECTION_01_230: [OPEN_PIPE ** HDR] */
            case CONNECTION_STATE_OC_PIPE:
                /* Codes_SRS_CONNECTION_01_232: [OC_PIPE - HDR TCP Close for Write] */
            case CONNECTION_STATE_CLOSE_RCVD:
                /* Codes_SRS_CONNECTION_01_234: [CLOSE_RCVD * - TCP Close for Read] */
            case CONNECTION_STATE_END:
                /* Codes_SRS_CONNECTION_01_237: [END - - TCP Close] */
                if (xio_close(connection->io, NULL, NULL) != 0)
                {
                    LogError("xio_close failed");
                }
                break;
            }
        }
    }
}

static void frame_codec_error(void* context)
{
    /* Bug: some error handling should happen here 
    Filed: uAMQP: frame_codec error and amqp_frame_codec_error should handle the errors */
    LogError("A frame_codec_error occured");
    (void)context;
}

static void amqp_frame_codec_error(void* context)
{
    /* Bug: some error handling should happen here
    Filed: uAMQP: frame_codec error and amqp_frame_codec_error should handle the errors */
    LogError("An amqp_frame_codec_error occured");
    (void)context;
}

/* Codes_SRS_CONNECTION_01_001: [connection_create shall open a new connection to a specified host/port.] */
CONNECTION_HANDLE connection_create(XIO_HANDLE xio, const char* hostname, const char* container_id, ON_NEW_ENDPOINT on_new_endpoint, void* callback_context)
{
    return connection_create2(xio, hostname, container_id, on_new_endpoint, callback_context, NULL, NULL, NULL, NULL);
}

/* Codes_SRS_CONNECTION_01_001: [connection_create shall open a new connection to a specified host/port.] */
/* Codes_SRS_CONNECTION_22_002: [connection_create shall allow registering connections state and io error callbacks.] */
CONNECTION_HANDLE connection_create2(XIO_HANDLE xio, const char* hostname, const char* container_id, ON_NEW_ENDPOINT on_new_endpoint, void* callback_context, ON_CONNECTION_STATE_CHANGED on_connection_state_changed, void* on_connection_state_changed_context, ON_IO_ERROR on_io_error, void* on_io_error_context)
{
    CONNECTION_HANDLE connection;

    if ((xio == NULL) ||
        (container_id == NULL))
    {
        /* Codes_SRS_CONNECTION_01_071: [If xio or container_id is NULL, connection_create shall return NULL.] */
        LogError("Bad arguments: xio = %p, container_id = %p",
            xio, container_id);
        connection = NULL;
    }
    else
    {
        connection = (CONNECTION_HANDLE)malloc(sizeof(CONNECTION_INSTANCE));
        /* Codes_SRS_CONNECTION_01_081: [If allocating the memory for the connection fails then connection_create shall return NULL.] */
        if (connection == NULL)
        {
            LogError("Cannot allocate memory for connection");
        }
        else
        {
            connection->io = xio;

            /* Codes_SRS_CONNECTION_01_082: [connection_create shall allocate a new frame_codec instance to be used for frame encoding/decoding.] */
            connection->frame_codec = frame_codec_create(frame_codec_error, connection);
            if (connection->frame_codec == NULL)
            {
                /* Codes_SRS_CONNECTION_01_083: [If frame_codec_create fails then connection_create shall return NULL.] */
                LogError("Cannot create frame_codec");
                free(connection);
                connection = NULL;
            }
            else
            {
                connection->amqp_frame_codec = amqp_frame_codec_create(connection->frame_codec, on_amqp_frame_received, on_empty_amqp_frame_received, amqp_frame_codec_error, connection);
                if (connection->amqp_frame_codec == NULL)
                {
                    /* Codes_SRS_CONNECTION_01_108: [If amqp_frame_codec_create fails, connection_create shall return NULL.] */
                    LogError("Cannot create amqp_frame_codec");
                    frame_codec_destroy(connection->frame_codec);
                    free(connection);
                    connection = NULL;
                }
                else
                {
                    if (hostname != NULL)
                    {
                        size_t hostname_length = strlen(hostname);
                        connection->host_name = (char*)malloc(hostname_length + 1);
                        if (connection->host_name == NULL)
                        {
                            /* Codes_SRS_CONNECTION_01_081: [If allocating the memory for the connection fails then connection_create shall return NULL.] */
                            LogError("Cannot allocate memory for host name");
                            amqp_frame_codec_destroy(connection->amqp_frame_codec);
                            frame_codec_destroy(connection->frame_codec);
                            free(connection);
                            connection = NULL;
                        }
                        else
                        {
                            (void)memcpy(connection->host_name, hostname, hostname_length + 1);
                        }
                    }
                    else
                    {
                        connection->host_name = NULL;
                    }

                    if (connection != NULL)
                    {
                        size_t container_id_length = strlen(container_id);
                        connection->container_id = (char*)malloc(container_id_length + 1);
                        if (connection->container_id == NULL)
                        {
                            /* Codes_SRS_CONNECTION_01_081: [If allocating the memory for the connection fails then connection_create shall return NULL.] */
                            LogError("Cannot allocate memory for container_id");
                            free(connection->host_name);
                            amqp_frame_codec_destroy(connection->amqp_frame_codec);
                            frame_codec_destroy(connection->frame_codec);
                            free(connection);
                            connection = NULL;
                        }
                        else
                        {
                            connection->tick_counter = tickcounter_create();
                            if (connection->tick_counter == NULL)
                            {
                                LogError("Cannot create tick counter");
                                free(connection->container_id);
                                free(connection->host_name);
                                amqp_frame_codec_destroy(connection->amqp_frame_codec);
                                frame_codec_destroy(connection->frame_codec);
                                free(connection);
                                connection = NULL;
                            }
                            else
                            {
                                (void)memcpy(connection->container_id, container_id, container_id_length + 1);

                                /* Codes_SRS_CONNECTION_01_173: [<field name="max-frame-size" type="uint" default="4294967295"/>] */
                                connection->max_frame_size = 4294967295u;
                                /* Codes: [<field name="channel-max" type="ushort" default="65535"/>] */
                                connection->channel_max = 65535;

                                /* Codes_SRS_CONNECTION_01_175: [<field name="idle-time-out" type="milliseconds"/>] */
                                /* Codes_SRS_CONNECTION_01_192: [A value of zero is the same as if it was not set (null).] */
                                connection->idle_timeout = 0;
                                connection->remote_idle_timeout = 0;
                                connection->remote_idle_timeout_send_frame_millisecond = 0;
                                connection->idle_timeout_empty_frame_send_ratio = 0.5;

                                connection->endpoint_count = 0;
                                connection->endpoints = NULL;
                                connection->header_bytes_received = 0;
                                connection->is_remote_frame_received = 0;

                                connection->is_underlying_io_open = 0;
                                connection->remote_max_frame_size = 512;
                                connection->is_trace_on = 0;

                                /* Mark that settings have not yet been set by the user */
                                connection->idle_timeout_specified = 0;

                                connection->on_new_endpoint = on_new_endpoint;
                                connection->on_new_endpoint_callback_context = callback_context;

                                connection->on_io_error = on_io_error;
                                connection->on_io_error_callback_context = on_io_error_context;
                                connection->on_connection_state_changed = on_connection_state_changed;
                                connection->on_connection_state_changed_callback_context = on_connection_state_changed_context;

                                if (tickcounter_get_current_ms(connection->tick_counter, &connection->last_frame_received_time) != 0)
                                {
                                    LogError("Could not retrieve time for last frame received time");
                                    tickcounter_destroy(connection->tick_counter);
                                    free(connection->container_id);
                                    free(connection->host_name);
                                    amqp_frame_codec_destroy(connection->amqp_frame_codec);
                                    frame_codec_destroy(connection->frame_codec);
                                    free(connection);
                                    connection = NULL;
                                }
                                else
                                {
                                    connection->last_frame_sent_time = connection->last_frame_received_time;

                                    /* Codes_SRS_CONNECTION_01_072: [When connection_create succeeds, the state of the connection shall be CONNECTION_STATE_START.] */
                                    connection_set_state(connection, CONNECTION_STATE_START);
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    return connection;
}

void connection_destroy(CONNECTION_HANDLE connection)
{
    /* Codes_SRS_CONNECTION_01_079: [If handle is NULL, connection_destroy shall do nothing.] */
    if (connection == NULL)
    {
        LogError("NULL connection");
    }
    else
    {
        /* Codes_SRS_CONNECTION_01_073: [connection_destroy shall free all resources associated with a connection.] */
        if (connection->is_underlying_io_open)
        {
            (void)connection_close(connection, NULL, NULL);
        }

        amqp_frame_codec_destroy(connection->amqp_frame_codec);
        frame_codec_destroy(connection->frame_codec);
        tickcounter_destroy(connection->tick_counter);

        free(connection->host_name);
        free(connection->container_id);

        /* Codes_SRS_CONNECTION_01_074: [connection_destroy shall close the socket connection.] */
        free(connection);
    }
}

int connection_open(CONNECTION_HANDLE connection)
{
    int result;

    if (connection == NULL)
    {
        LogError("NULL connection");
        result = __FAILURE__;
    }
    else
    {
        if (!connection->is_underlying_io_open)
        {
            if (xio_open(connection->io, connection_on_io_open_complete, connection, connection_on_bytes_received, connection, connection_on_io_error, connection) != 0)
            {
                LogError("Opening the underlying IO failed");
                connection_set_state(connection, CONNECTION_STATE_END);
                result = __FAILURE__;
            }
            else
            {
                connection->is_underlying_io_open = 1;

                connection_set_state(connection, CONNECTION_STATE_START);

                result = 0;
            }
        }
        else
        {
            result = 0;
        }
    }

    return result;
}

int connection_listen(CONNECTION_HANDLE connection)
{
    int result;

    if (connection == NULL)
    {
        LogError("NULL connection");
        result = __FAILURE__;
    }
    else
    {
        if (!connection->is_underlying_io_open)
        {
            if (xio_open(connection->io, connection_on_io_open_complete, connection, connection_on_bytes_received, connection, connection_on_io_error, connection) != 0)
            {
                LogError("Opening the underlying IO failed");
                connection_set_state(connection, CONNECTION_STATE_END);
                result = __FAILURE__;
            }
            else
            {
                connection->is_underlying_io_open = 1;

                connection_set_state(connection, CONNECTION_STATE_HDR_EXCH);

                result = 0;
            }
        }
        else
        {
            result = 0;
        }
    }

    return result;
}

int connection_close(CONNECTION_HANDLE connection, const char* condition_value, const char* description)
{
    int result;

    if (connection == NULL)
    {
        LogError("NULL connection");
        result = __FAILURE__;
    }
    else
    {
        if (condition_value != NULL)
        {
            close_connection_with_error(connection, condition_value, description);
        }
        else
        {
            if (send_close_frame(connection, NULL) != 0)
            {
                LogError("Sending CLOSE frame failed");
            }

            connection_set_state(connection, CONNECTION_STATE_END);
        }

        if (xio_close(connection->io, NULL, NULL) != 0)
        {
            LogError("xio_close failed");
        }

        connection->is_underlying_io_open = 1;

        result = 0;
    }

    return result;
}

int connection_set_max_frame_size(CONNECTION_HANDLE connection, uint32_t max_frame_size)
{
    int result;

    /* Codes_SRS_CONNECTION_01_163: [If connection is NULL, connection_set_max_frame_size shall fail and return a non-zero value.] */
    if (connection == NULL)
    {
        LogError("NULL connection");
        result = __FAILURE__;
    }
    /* Codes_SRS_CONNECTION_01_150: [If the max_frame_size is invalid then connection_set_max_frame_size shall fail and return a non-zero value.] */
    /* Codes_SRS_CONNECTION_01_167: [Both peers MUST accept frames of up to 512 (MIN-MAX-FRAME-SIZE) octets.] */
    else if (max_frame_size < 512)
    {
        LogError("max_frame_size too small");
        result = __FAILURE__;
    }
    else
    {
        /* Codes_SRS_CONNECTION_01_157: [If connection_set_max_frame_size is called after the initial Open frame has been sent, it shall fail and return a non-zero value.] */
        if (connection->connection_state != CONNECTION_STATE_START)
        {
            LogError("Connection already open");
            result = __FAILURE__;
        }
        else
        {
            /* Codes_SRS_CONNECTION_01_148: [connection_set_max_frame_size shall set the max_frame_size associated with a connection.] */
            /* Codes_SRS_CONNECTION_01_164: [If connection_set_max_frame_size fails, the previous max_frame_size setting shall be retained.] */
            connection->max_frame_size = max_frame_size;

            /* Codes_SRS_CONNECTION_01_149: [On success connection_set_max_frame_size shall return 0.] */
            result = 0;
        }
    }

    return result;
}

int connection_get_max_frame_size(CONNECTION_HANDLE connection, uint32_t* max_frame_size)
{
    int result;

    /* Codes_SRS_CONNECTION_01_170: [If connection or max_frame_size is NULL, connection_get_max_frame_size shall fail and return a non-zero value.] */
    if ((connection == NULL) ||
        (max_frame_size == NULL))
    {
        LogError("Bad arguments: connection = %p, max_frame_size = %p",
            connection, max_frame_size);
        result = __FAILURE__;
    }
    else
    {
        /* Codes_SRS_CONNECTION_01_168: [connection_get_max_frame_size shall return in the max_frame_size argument the current max frame size setting.] */
        *max_frame_size = connection->max_frame_size;

        /* Codes_SRS_CONNECTION_01_169: [On success, connection_get_max_frame_size shall return 0.] */
        result = 0;
    }

    return result;
}

int connection_set_channel_max(CONNECTION_HANDLE connection, uint16_t channel_max)
{
    int result;

    /* Codes_SRS_CONNECTION_01_181: [If connection is NULL then connection_set_channel_max shall fail and return a non-zero value.] */
    if (connection == NULL)
    {
        LogError("NULL connection");
        result = __FAILURE__;
    }
    else
    {
        /* Codes_SRS_CONNECTION_01_156: [If connection_set_channel_max is called after the initial Open frame has been sent, it shall fail and return a non-zero value.] */
        if (connection->connection_state != CONNECTION_STATE_START)
        {
            LogError("Connection already open");
            result = __FAILURE__;
        }
        else
        {
            /* Codes_SRS_CONNECTION_01_153: [connection_set_channel_max shall set the channel_max associated with a connection.] */
            /* Codes_SRS_CONNECTION_01_165: [If connection_set_channel_max fails, the previous channel_max setting shall be retained.] */
            connection->channel_max = channel_max;

            /* Codes_SRS_CONNECTION_01_154: [On success connection_set_channel_max shall return 0.] */
            result = 0;
        }
    }

    return result;
}

int connection_get_channel_max(CONNECTION_HANDLE connection, uint16_t* channel_max)
{
    int result;

    /* Codes_SRS_CONNECTION_01_184: [If connection or channel_max is NULL, connection_get_channel_max shall fail and return a non-zero value.] */
    if ((connection == NULL) ||
        (channel_max == NULL))
    {
        LogError("Bad arguments: connection = %p, channel_max = %p",
            connection, channel_max);
        result = __FAILURE__;
    }
    else
    {
        /* Codes_SRS_CONNECTION_01_182: [connection_get_channel_max shall return in the channel_max argument the current channel_max setting.] */
        *channel_max = connection->channel_max;

        /* Codes_SRS_CONNECTION_01_183: [On success, connection_get_channel_max shall return 0.] */
        result = 0;
    }

    return result;
}

int connection_set_idle_timeout(CONNECTION_HANDLE connection, milliseconds idle_timeout)
{
    int result;

    /* Codes_SRS_CONNECTION_01_191: [If connection is NULL, connection_set_idle_timeout shall fail and return a non-zero value.] */
    if (connection == NULL)
    {
        LogError("NULL connection");
        result = __FAILURE__;
    }
    else
    {
        /* Codes_SRS_CONNECTION_01_158: [If connection_set_idle_timeout is called after the initial Open frame has been sent, it shall fail and return a non-zero value.] */
        if (connection->connection_state != CONNECTION_STATE_START)
        {
            LogError("Connection already open");
            result = __FAILURE__;
        }
        else
        {
            /* Codes_SRS_CONNECTION_01_159: [connection_set_idle_timeout shall set the idle_timeout associated with a connection.] */
            /* Codes_SRS_CONNECTION_01_166: [If connection_set_idle_timeout fails, the previous idle_timeout setting shall be retained.] */
            connection->idle_timeout = idle_timeout;
            connection->idle_timeout_specified = true;

            /* Codes_SRS_CONNECTION_01_160: [On success connection_set_idle_timeout shall return 0.] */
            result = 0;
        }
    }

    return result;
}

int connection_get_idle_timeout(CONNECTION_HANDLE connection, milliseconds* idle_timeout)
{
    int result;

    /* Codes_SRS_CONNECTION_01_190: [If connection or idle_timeout is NULL, connection_get_idle_timeout shall fail and return a non-zero value.] */
    if ((connection == NULL) ||
        (idle_timeout == NULL))
    {
        LogError("Bad arguments: connection = %p, idle_timeout = %p",
            connection, idle_timeout);
        result = __FAILURE__;
    }
    else
    {
        /* Codes_SRS_CONNECTION_01_188: [connection_get_idle_timeout shall return in the idle_timeout argument the current idle_timeout setting.] */
        *idle_timeout = connection->idle_timeout;

        /* Codes_SRS_CONNECTION_01_189: [On success, connection_get_idle_timeout shall return 0.] */
        result = 0;
    }

    return result;
}

int connection_get_remote_max_frame_size(CONNECTION_HANDLE connection, uint32_t* remote_max_frame_size)
{
    int result;

    if ((connection == NULL) ||
        (remote_max_frame_size == NULL))
    {
        LogError("Bad arguments: connection = %p, remote_max_frame_size = %p",
            connection, remote_max_frame_size);
        result = __FAILURE__;
    }
    else
    {
        *remote_max_frame_size = connection->remote_max_frame_size;

        result = 0;
    }

    return result;
}

uint64_t connection_handle_deadlines(CONNECTION_HANDLE connection)
{
    uint64_t local_deadline = (uint64_t)-1;
    uint64_t remote_deadline = (uint64_t)-1;

    if (connection == NULL)
    {
        LogError("NULL connection");
    }
    else
    {
        tickcounter_ms_t current_ms;

        if (tickcounter_get_current_ms(connection->tick_counter, &current_ms) != 0)
        {
            LogError("Could not get tick counter value");
            close_connection_with_error(connection, "amqp:internal-error", "Could not get tick count");
        }
        else
        {
            if (connection->idle_timeout_specified && (connection->idle_timeout != 0))
            {
                /* Calculate time until configured idle timeout expires */

                uint64_t time_since_last_received = current_ms - connection->last_frame_received_time;
                if (time_since_last_received < connection->idle_timeout)
                {
                    local_deadline = connection->idle_timeout - time_since_last_received;
                }
                else
                {
                    local_deadline = 0;

                    /* close connection */
                    close_connection_with_error(connection, "amqp:internal-error", "No frame received for the idle timeout");
                }
            }

            if (local_deadline != 0 && connection->remote_idle_timeout != 0)
            {
                /* Calculate time until remote idle timeout expires */

                uint64_t remote_idle_timeout = connection->remote_idle_timeout_send_frame_millisecond;
                uint64_t time_since_last_sent = current_ms - connection->last_frame_sent_time;

                if (time_since_last_sent < remote_idle_timeout)
                {
                    remote_deadline = remote_idle_timeout - time_since_last_sent;
                }
                else
                {
                    connection->on_send_complete = NULL;
                    if (amqp_frame_codec_encode_empty_frame(connection->amqp_frame_codec, 0, on_bytes_encoded, connection) != 0)
                    {
                        LogError("Encoding the empty frame failed");
                        /* close connection */
                        close_connection_with_error(connection, "amqp:internal-error", "Cannot send empty frame");
                    }
                    else
                    {
                        if (connection->is_trace_on == 1)
                        {
                            LOG(AZ_LOG_TRACE, LOG_LINE, "-> Empty frame");
                        }

                        connection->last_frame_sent_time = current_ms;

                        remote_deadline = remote_idle_timeout;
                    }
                }
            }
        }
    }

    /* Return the shorter of each deadline, or 0 to indicate connection closed */
    return local_deadline > remote_deadline ? remote_deadline : local_deadline;
}

void connection_dowork(CONNECTION_HANDLE connection)
{
    /* Codes_SRS_CONNECTION_01_078: [If handle is NULL, connection_dowork shall do nothing.] */
    if (connection == NULL)
    {
        LogError("NULL connection");
    }
    else
    {
        if (connection_handle_deadlines(connection) > 0)
        {
            /* Codes_SRS_CONNECTION_01_076: [connection_dowork shall schedule the underlying IO interface to do its work by calling xio_dowork.] */
            xio_dowork(connection->io);
        }
    }
}

ENDPOINT_HANDLE connection_create_endpoint(CONNECTION_HANDLE connection)
{
    ENDPOINT_HANDLE result;

    /* Codes_SRS_CONNECTION_01_113: [If connection, on_endpoint_frame_received or on_connection_state_changed is NULL, connection_create_endpoint shall fail and return NULL.] */
    /* Codes_SRS_CONNECTION_01_193: [The context argument shall be allowed to be NULL.] */
    if (connection == NULL)
    {
        LogError("NULL connection");
        result = NULL;
    }
    else
    {
        /* Codes_SRS_CONNECTION_01_115: [If no more endpoints can be created due to all channels being used, connection_create_endpoint shall fail and return NULL.] */
        if (connection->endpoint_count >= connection->channel_max)
        {
            result = NULL;
        }
        else
        {
            uint32_t i = 0;

            /* Codes_SRS_CONNECTION_01_128: [The lowest number outgoing channel shall be associated with the newly created endpoint.] */
            for (i = 0; i < connection->endpoint_count; i++)
            {
                if (connection->endpoints[i]->outgoing_channel > i)
                {
                    /* found a gap in the sorted endpoint array */
                    break;
                }
            }

            /* Codes_SRS_CONNECTION_01_127: [On success, connection_create_endpoint shall return a non-NULL handle to the newly created endpoint.] */
            result = (ENDPOINT_HANDLE)malloc(sizeof(ENDPOINT_INSTANCE));
            /* Codes_SRS_CONNECTION_01_196: [If memory cannot be allocated for the new endpoint, connection_create_endpoint shall fail and return NULL.] */
            if (result == NULL)
            {
                LogError("Cannot allocate memory for endpoint");
            }
            else
            {
                ENDPOINT_HANDLE* new_endpoints;

                result->on_endpoint_frame_received = NULL;
                result->on_connection_state_changed = NULL;
                result->callback_context = NULL;
                result->outgoing_channel = (uint16_t)i;
                result->connection = connection;

                /* Codes_SRS_CONNECTION_01_197: [The newly created endpoint shall be added to the endpoints list, so that it can be tracked.] */
                new_endpoints = (ENDPOINT_HANDLE*)realloc(connection->endpoints, sizeof(ENDPOINT_HANDLE) * (connection->endpoint_count + 1));
                if (new_endpoints == NULL)
                {
                    /* Tests_SRS_CONNECTION_01_198: [If adding the endpoint to the endpoints list tracked by the connection fails, connection_create_endpoint shall fail and return NULL.] */
                    LogError("Cannot reallocate memory for connection endpoints");
                    free(result);
                    result = NULL;
                }
                else
                {
                    connection->endpoints = new_endpoints;

                    if (i < connection->endpoint_count)
                    {
                        (void)memmove(&connection->endpoints[i + 1], &connection->endpoints[i], sizeof(ENDPOINT_INSTANCE*) * (connection->endpoint_count - i));
                    }

                    connection->endpoints[i] = result;
                    connection->endpoint_count++;

                    /* Codes_SRS_CONNECTION_01_112: [connection_create_endpoint shall create a new endpoint that can be used by a session.] */
                }
            }
        }
    }

    return result;
}

int connection_start_endpoint(ENDPOINT_HANDLE endpoint, ON_ENDPOINT_FRAME_RECEIVED on_endpoint_frame_received, ON_CONNECTION_STATE_CHANGED on_connection_state_changed, void* context)
{
    int result;

    if ((endpoint == NULL) ||
        (on_endpoint_frame_received == NULL) ||
        (on_connection_state_changed == NULL))
    {
        LogError("Bad arguments: endpoint = %p, on_endpoint_frame_received = %p, on_connection_state_changed = %p",
            endpoint, on_endpoint_frame_received, on_connection_state_changed);
        result = __FAILURE__;
    }
    else
    {
        endpoint->on_endpoint_frame_received = on_endpoint_frame_received;
        endpoint->on_connection_state_changed = on_connection_state_changed;
        endpoint->callback_context = context;

        result = 0;
    }

    return result;
}

int connection_endpoint_get_incoming_channel(ENDPOINT_HANDLE endpoint, uint16_t* incoming_channel)
{
    int result;

    if ((endpoint == NULL) ||
        (incoming_channel == NULL))
    {
        LogError("Bad arguments: endpoint = %p, incoming_channel = %p",
            endpoint, incoming_channel);
        result = __FAILURE__;
    }
    else
    {
        *incoming_channel = endpoint->incoming_channel;
        result = 0;
    }

    return result;
}

/* Codes_SRS_CONNECTION_01_129: [connection_destroy_endpoint shall free all resources associated with an endpoint created by connection_create_endpoint.] */
void connection_destroy_endpoint(ENDPOINT_HANDLE endpoint)
{
    if (endpoint == NULL)
    {
        LogError("NULL endpoint");
    }
    else
    {
        CONNECTION_HANDLE connection = (CONNECTION_HANDLE)endpoint->connection;
        size_t i;

        for (i = 0; i < connection->endpoint_count; i++)
        {
            if (connection->endpoints[i] == endpoint)
            {
                break;
            }
        }

        /* Codes_SRS_CONNECTION_01_130: [The outgoing channel associated with the endpoint shall be released by removing the endpoint from the endpoint list.] */
        /* Codes_SRS_CONNECTION_01_131: [Any incoming channel number associated with the endpoint shall be released.] */
        if ((i < connection->endpoint_count) && (i > 0))
        {
            ENDPOINT_HANDLE* new_endpoints;
            (void)memmove(connection->endpoints + i, connection->endpoints + i + 1, sizeof(ENDPOINT_HANDLE) * (connection->endpoint_count - i - 1));

            new_endpoints = (ENDPOINT_HANDLE*)realloc(connection->endpoints, (connection->endpoint_count - 1) * sizeof(ENDPOINT_HANDLE));
            if (new_endpoints != NULL)
            {
                connection->endpoints = new_endpoints;
            }

            connection->endpoint_count--;
        }
        else if (connection->endpoint_count == 1)
        {
            free(connection->endpoints);
            connection->endpoints = NULL;
            connection->endpoint_count = 0;
        }

        free(endpoint);
    }
}

/* Codes_SRS_CONNECTION_01_247: [connection_encode_frame shall send a frame for a certain endpoint.] */
int connection_encode_frame(ENDPOINT_HANDLE endpoint, AMQP_VALUE performative, PAYLOAD* payloads, size_t payload_count, ON_SEND_COMPLETE on_send_complete, void* callback_context)
{
    int result;

    /* Codes_SRS_CONNECTION_01_249: [If endpoint or performative are NULL, connection_encode_frame shall fail and return a non-zero value.] */
    if ((endpoint == NULL) ||
        (performative == NULL))
    {
        LogError("Bad arguments: endpoint = %p, performative = %p",
            endpoint, performative);
        result = __FAILURE__;
    }
    else
    {
        CONNECTION_HANDLE connection = (CONNECTION_HANDLE)endpoint->connection;
        AMQP_FRAME_CODEC_HANDLE amqp_frame_codec = connection->amqp_frame_codec;

        /* Codes_SRS_CONNECTION_01_254: [If connection_encode_frame is called before the connection is in the OPENED state, connection_encode_frame shall fail and return a non-zero value.] */
        if (connection->connection_state != CONNECTION_STATE_OPENED)
        {
            LogError("Connection not open");
            result = __FAILURE__;
        }
        else
        {
            /* Codes_SRS_CONNECTION_01_255: [The payload size shall be computed based on all the payload chunks passed as argument in payloads.] */
            /* Codes_SRS_CONNECTION_01_250: [connection_encode_frame shall initiate the frame send by calling amqp_frame_codec_begin_encode_frame.] */
            /* Codes_SRS_CONNECTION_01_251: [The channel number passed to amqp_frame_codec_begin_encode_frame shall be the outgoing channel number associated with the endpoint by connection_create_endpoint.] */
            /* Codes_SRS_CONNECTION_01_252: [The performative passed to amqp_frame_codec_begin_encode_frame shall be the performative argument of connection_encode_frame.] */
            connection->on_send_complete = on_send_complete;
            connection->on_send_complete_callback_context = callback_context;
            if (amqp_frame_codec_encode_frame(amqp_frame_codec, endpoint->outgoing_channel, performative, payloads, payload_count, on_bytes_encoded, connection) != 0)
            {
                /* Codes_SRS_CONNECTION_01_253: [If amqp_frame_codec_begin_encode_frame or amqp_frame_codec_encode_payload_bytes fails, then connection_encode_frame shall fail and return a non-zero value.] */
                LogError("Encoding AMQP frame failed");
                result = __FAILURE__;
            }
            else
            {
                if (connection->is_trace_on == 1)
                {
                    log_outgoing_frame(performative);
                }

                if (tickcounter_get_current_ms(connection->tick_counter, &connection->last_frame_sent_time) != 0)
                {
                    LogError("Getting tick counter value failed");
                    result = __FAILURE__;
                }
                else
                {
                    /* Codes_SRS_CONNECTION_01_248: [On success it shall return 0.] */
                    result = 0;
                }
            }
        }
    }

    return result;
}

void connection_set_trace(CONNECTION_HANDLE connection, bool trace_on)
{
    /* Codes_SRS_CONNECTION_07_002: [If connection is NULL then connection_set_trace shall do nothing.] */
    if (connection == NULL)
    {
        LogError("NULL connection");
    }
    else
    {
        /* Codes_SRS_CONNECTION_07_001: [connection_set_trace shall set the ability to turn on and off trace logging.] */
        connection->is_trace_on = trace_on ? 1 : 0;
    }
}

int connection_set_remote_idle_timeout_empty_frame_send_ratio(CONNECTION_HANDLE connection, double idle_timeout_empty_frame_send_ratio)
{
    int result;

    if ((connection == NULL) ||
        (idle_timeout_empty_frame_send_ratio <= 0.0) ||
        (idle_timeout_empty_frame_send_ratio > 1.0))
    {
        LogError("Bad arguments: connection = %p, idle_timeout_empty_frame_send_ratio = %f",
            connection, idle_timeout_empty_frame_send_ratio);
        result = __FAILURE__;
    }
    else
    {
        connection->idle_timeout_empty_frame_send_ratio = idle_timeout_empty_frame_send_ratio;
        result = 0;
    }

    return result;
}