amqp_connection_resource.c

/*
  +----------------------------------------------------------------------+
  | PHP Version 5                                                        |
  +----------------------------------------------------------------------+
  | Copyright (c) 1997-2007 The PHP Group                                |
  +----------------------------------------------------------------------+
  | This source file is subject to version 3.01 of the PHP license,      |
  | that is bundled with this package in the file LICENSE, and is        |
  | available through the world-wide-web at the following url:           |
  | http://www.php.net/license/3_01.txt                                  |
  | If you did not receive a copy of the PHP license and are unable to   |
  | obtain it through the world-wide-web, please send a note to          |
  | license@php.net so we can mail you a copy immediately.               |
  +----------------------------------------------------------------------+
  | Author: Alexandre Kalendarev akalend@mail.ru Copyright (c) 2009-2010 |
  | Lead:                                                                |
  | - Pieter de Zwart                                                    |
  | Maintainers:                                                         |
  | - Brad Rodriguez                                                     |
  | - Jonathan Tansavatdi                                                |
  +----------------------------------------------------------------------+
*/

#ifdef HAVE_CONFIG_H
    #include "config.h"
#endif

#include "php.h"
#include "ext/standard/datetime.h"
#include "zend_exceptions.h"

#ifdef PHP_WIN32
    #if PHP_VERSION_ID >= 80000
        #include <stdint.h>
    #else
        #include "win32/php_stdint.h"
    #endif
    #include "win32/signal.h"
#else
    #include <signal.h>
    #include <stdint.h>
#endif

#if HAVE_LIBRABBITMQ_NEW_LAYOUT
    #include <rabbitmq-c/amqp.h>
    #include <rabbitmq-c/framing.h>
    #include <rabbitmq-c/tcp_socket.h>
    #include <rabbitmq-c/ssl_socket.h>
#else
    #include <amqp.h>
    #include <amqp_framing.h>
    #include <amqp_tcp_socket.h>
    #include <amqp_ssl_socket.h>
#endif

#ifdef PHP_WIN32
    #include "win32/unistd.h"
#else
    #include <unistd.h>
#endif

#include "amqp_methods_handling.h"
#include "amqp_connection_resource.h"
#include "amqp_channel.h"
#include "php_amqp.h"

#ifndef E_DEPRECATED
    #define E_DEPRECATED E_WARNING
#endif

int le_amqp_connection_resource;
int le_amqp_connection_resource_persistent;

static void connection_resource_destructor(amqp_connection_resource *resource, int persistent);
static void php_amqp_close_connection_from_server(
    amqp_rpc_reply_t reply,
    char **message,
    amqp_connection_resource *resource
);
static void php_amqp_close_channel_from_server(
    amqp_rpc_reply_t reply,
    char **message,
    amqp_connection_resource *resource,
    amqp_channel_t channel_id
);


/* Figure out what's going on connection and handle protocol exceptions, if any */
int php_amqp_connection_resource_error(
    amqp_rpc_reply_t reply,
    char **message,
    amqp_connection_resource *resource,
    amqp_channel_t channel_id
)
{
    assert(resource != NULL);

    switch (reply.reply_type) {
        case AMQP_RESPONSE_NORMAL:
            return PHP_AMQP_RESOURCE_RESPONSE_OK;

        case AMQP_RESPONSE_NONE:
            spprintf(message, 0, "Missing RPC reply type.");
            return PHP_AMQP_RESOURCE_RESPONSE_ERROR;

        case AMQP_RESPONSE_LIBRARY_EXCEPTION:
            spprintf(message, 0, "Library error: %s", amqp_error_string2(reply.library_error));
            return PHP_AMQP_RESOURCE_RESPONSE_ERROR;

        case AMQP_RESPONSE_SERVER_EXCEPTION:
            switch (reply.reply.id) {
                case AMQP_CONNECTION_CLOSE_METHOD: {
                    php_amqp_close_connection_from_server(reply, message, resource);
                    return PHP_AMQP_RESOURCE_RESPONSE_ERROR_CONNECTION_CLOSED;
                }
                case AMQP_CHANNEL_CLOSE_METHOD: {
                    php_amqp_close_channel_from_server(reply, message, resource, channel_id);
                    return PHP_AMQP_RESOURCE_RESPONSE_ERROR_CHANNEL_CLOSED;
                }
            }
        /* Default for the above switch should be handled by the below default. */
        default:
            spprintf(message, 0, "Unknown server error, method id 0x%08X", reply.reply.id);
            return PHP_AMQP_RESOURCE_RESPONSE_ERROR;
    }

    /* Should not never get here*/
}

static void php_amqp_close_connection_from_server(
    amqp_rpc_reply_t reply,
    char **message,
    amqp_connection_resource *resource
)
{
    amqp_connection_close_t *m = (amqp_connection_close_t *) reply.reply.decoded;
    int result;

    if (!reply.reply.id) {
        PHP_AMQP_G(error_code) = -1;
        spprintf(
            message,
            0,
            "Server connection error: %ld, message: %s",
            (long) PHP_AMQP_G(error_code),
            "unexpected response"
        );
    } else {
        PHP_AMQP_G(error_code) = m->reply_code;
        spprintf(
            message,
            0,
            "Server connection error: %d, message: %.*s",
            m->reply_code,
            (int) m->reply_text.len,
            (char *) m->reply_text.bytes
        );
    }

    /*
	 *    - If r.reply.id == AMQP_CONNECTION_CLOSE_METHOD a connection exception
	 *      occurred, cast r.reply.decoded to amqp_connection_close_t* to see
	 *      details of the exception. The client amqp_send_method() a
	 *      amqp_connection_close_ok_t and disconnect from the broker.
	 */

    amqp_connection_close_ok_t *decoded = (amqp_connection_close_ok_t *) NULL;

    result = amqp_send_method(
        resource->connection_state,
        0, /* NOTE: 0-channel is reserved for things like this */
        AMQP_CONNECTION_CLOSE_OK_METHOD,
        &decoded
    );

    if (result != AMQP_STATUS_OK) {
        zend_throw_exception(amqp_channel_exception_class_entry, "An error occurred while closing the connection.", 0);
    }

    /* Prevent finishing AMQP connection in connection resource destructor */
    resource->is_connected = '\0';
}

static void php_amqp_close_channel_from_server(
    amqp_rpc_reply_t reply,
    char **message,
    amqp_connection_resource *resource,
    amqp_channel_t channel_id
)
{
    assert(channel_id > 0 && channel_id <= resource->max_slots);

    amqp_channel_close_t *m = (amqp_channel_close_t *) reply.reply.decoded;

    if (!reply.reply.id) {
        PHP_AMQP_G(error_code) = -1;
        spprintf(
            message,
            0,
            "Server channel error: %ld, message: %s",
            (long) PHP_AMQP_G(error_code),
            "unexpected response"
        );
    } else {
        PHP_AMQP_G(error_code) = m->reply_code;
        spprintf(
            message,
            0,
            "Server channel error: %d, message: %.*s",
            m->reply_code,
            (int) m->reply_text.len,
            (char *) m->reply_text.bytes
        );
    }

    /*
	 *    - If r.reply.id == AMQP_CHANNEL_CLOSE_METHOD a channel exception
	 *      occurred, cast r.reply.decoded to amqp_channel_close_t* to see details
	 *      of the exception. The client should amqp_send_method() a
	 *      amqp_channel_close_ok_t. The channel must be re-opened before it
	 *      can be used again. Any resources associated with the channel
	 *      (auto-delete exchanges, auto-delete queues, consumers) are invalid
	 *      and must be recreated before attempting to use them again.
	 */
    if (resource) {
        int result;
        amqp_channel_close_ok_t *decoded = (amqp_channel_close_ok_t *) NULL;

        result = amqp_send_method(resource->connection_state, channel_id, AMQP_CHANNEL_CLOSE_OK_METHOD, &decoded);
        if (result != AMQP_STATUS_OK) {
            zend_throw_exception(amqp_channel_exception_class_entry, "An error occurred while closing channel.", 0);
        }
    }
}


int php_amqp_connection_resource_error_advanced(
    amqp_rpc_reply_t reply,
    char **message,
    amqp_connection_resource *resource,
    amqp_channel_t channel_id,
    amqp_channel_object *channel
)
{
    assert(resource != NULL);

    amqp_frame_t frame;

    assert(AMQP_RESPONSE_LIBRARY_EXCEPTION == reply.reply_type);
    assert(AMQP_STATUS_UNEXPECTED_STATE == reply.library_error);

    if (channel_id < 0 || AMQP_STATUS_OK != amqp_simple_wait_frame(resource->connection_state, &frame)) {
        if (*message != NULL) {
            efree(*message);
        }

        spprintf(message, 0, "Library error: %s", amqp_error_string2(reply.library_error));
        return PHP_AMQP_RESOURCE_RESPONSE_ERROR;
    }

    if (channel_id != frame.channel) {
        spprintf(message, 0, "Library error: channel mismatch");
        return PHP_AMQP_RESOURCE_RESPONSE_ERROR;
    }

    if (AMQP_FRAME_METHOD == frame.frame_type) {
        switch (frame.payload.method.id) {
            case AMQP_CONNECTION_CLOSE_METHOD: {
                php_amqp_close_connection_from_server(reply, message, resource);
                return PHP_AMQP_RESOURCE_RESPONSE_ERROR_CONNECTION_CLOSED;
            }
            case AMQP_CHANNEL_CLOSE_METHOD: {
                php_amqp_close_channel_from_server(reply, message, resource, channel_id);
                return PHP_AMQP_RESOURCE_RESPONSE_ERROR_CHANNEL_CLOSED;
            }

            case AMQP_BASIC_ACK_METHOD:
                /* if we've turned publisher confirms on, and we've published a message
				 * here is a message being confirmed
				 */

                return php_amqp_handle_basic_ack(message, resource, channel_id, channel, &frame.payload.method);
            case AMQP_BASIC_NACK_METHOD:
                /* if we've turned publisher confirms on, and we've published a message
				 * here is a message being confirmed
				 */

                return php_amqp_handle_basic_nack(message, resource, channel_id, channel, &frame.payload.method);
            case AMQP_BASIC_RETURN_METHOD:
                /* if a published message couldn't be routed and the mandatory flag was set
				 * this is what would be returned. The message then needs to be read.
				 */

                return php_amqp_handle_basic_return(message, resource, channel_id, channel, &frame.payload.method);
            default:
                if (*message != NULL) {
                    efree(*message);
                }

                spprintf(
                    message,
                    0,
                    "Library error: An unexpected method was received 0x%08X\n",
                    frame.payload.method.id
                );
                return PHP_AMQP_RESOURCE_RESPONSE_ERROR;
        }
    }

    if (*message != NULL) {
        efree(*message);
    }

    spprintf(message, 0, "Library error: %s", amqp_error_string2(reply.library_error));
    return PHP_AMQP_RESOURCE_RESPONSE_ERROR;
}

/* Socket-related functions */
int php_amqp_set_resource_read_timeout(amqp_connection_resource *resource, double timeout)
{
    assert(timeout >= 0.0);

#ifdef PHP_WIN32
    DWORD read_timeout;
    /*
	In Windows, setsockopt with SO_RCVTIMEO sets actual timeout
	to a value that's 500ms greater than specified value.
	Also, it's not possible to set timeout to any value below 500ms.
	Zero timeout works like it should, however.
	*/
    if (timeout == 0.) {
        read_timeout = 0;
    } else {
        read_timeout = (int) (max(timeout * 1.e+3 - .5e+3, 1.));
    }
#else
    struct timeval read_timeout;
    read_timeout.tv_sec = (int) floor(timeout);
    read_timeout.tv_usec = (int) ((timeout - floor(timeout)) * 1.e+6);
#endif

    if (0 != setsockopt(
                 amqp_get_sockfd(resource->connection_state),
                 SOL_SOCKET,
                 SO_RCVTIMEO,
                 (char *) &read_timeout,
                 sizeof(read_timeout)
             )) {
        zend_throw_exception(amqp_connection_exception_class_entry, "Socket error: cannot setsockopt SO_RCVTIMEO", 0);
        return 0;
    }

    return 1;
}

int php_amqp_set_resource_rpc_timeout(amqp_connection_resource *resource, double timeout)
{
    assert(timeout >= 0.0);

#if AMQP_VERSION_MAJOR * 100 + AMQP_VERSION_MINOR * 10 + AMQP_VERSION_PATCH >= 90
    struct timeval rpc_timeout;

    if (timeout == 0.)
        return 1;

    rpc_timeout.tv_sec = (int) floor(timeout);
    rpc_timeout.tv_usec = (int) ((timeout - floor(timeout)) * 1.e+6);

    if (AMQP_STATUS_OK != amqp_set_rpc_timeout(resource->connection_state, &rpc_timeout)) {
        zend_throw_exception(amqp_connection_exception_class_entry, "Library error: cannot set rpc_timeout", 0);
        return 0;
    }
#endif

    return 1;
}

int php_amqp_set_resource_write_timeout(amqp_connection_resource *resource, double timeout)
{
    assert(timeout >= 0.0);

#ifdef PHP_WIN32
    DWORD write_timeout;

    if (timeout == 0.) {
        write_timeout = 0;
    } else {
        write_timeout = (int) (max(timeout * 1.e+3 - .5e+3, 1.));
    }
#else
    struct timeval write_timeout;
    write_timeout.tv_sec = (int) floor(timeout);
    write_timeout.tv_usec = (int) ((timeout - floor(timeout)) * 1.e+6);
#endif

    if (0 != setsockopt(
                 amqp_get_sockfd(resource->connection_state),
                 SOL_SOCKET,
                 SO_SNDTIMEO,
                 (char *) &write_timeout,
                 sizeof(write_timeout)
             )) {
        zend_throw_exception(amqp_connection_exception_class_entry, "Socket error: cannot setsockopt SO_SNDTIMEO", 0);
        return 0;
    }

    return 1;
}


/* Channel-related functions */

amqp_channel_t php_amqp_connection_resource_get_available_channel_id(amqp_connection_resource *resource)
{
    assert(resource != NULL);
    assert(resource->slots != NULL);

    /* Check if there are any open slots */
    if (resource->used_slots >= resource->max_slots) {
        return 0;
    }

    amqp_channel_t slot;

    for (slot = resource->used_slots; slot < resource->max_slots; slot++) {
        if (resource->slots[slot] == 0) {
            return (amqp_channel_t) (slot + 1);
        }
    }

    return 0;
}

int php_amqp_connection_resource_register_channel(
    amqp_connection_resource *resource,
    amqp_channel_resource *channel_resource,
    amqp_channel_t channel_id
)
{
    assert(resource != NULL);
    assert(resource->slots != NULL);
    assert(channel_id > 0 && channel_id <= resource->max_slots);

    if (resource->slots[channel_id - 1] != 0) {
        return FAILURE;
    }

    resource->slots[channel_id - 1] = channel_resource;
    channel_resource->connection_resource = resource;
    resource->used_slots++;

    return SUCCESS;
}

int php_amqp_connection_resource_unregister_channel(amqp_connection_resource *resource, amqp_channel_t channel_id)
{
    assert(resource != NULL);
    assert(resource->slots != NULL);
    assert(channel_id > 0 && channel_id <= resource->max_slots);

    if (resource->slots[channel_id - 1] != 0) {
        resource->slots[channel_id - 1]->connection_resource = NULL;

        resource->slots[channel_id - 1] = 0;
        resource->used_slots--;
    }

    return SUCCESS;
}


/* Creating and destroying resource */

amqp_connection_resource *connection_resource_constructor(amqp_connection_params *params, bool persistent)
{
    struct timeval tv = {0};
    struct timeval *tv_ptr = &tv;

    char *std_datetime;
    amqp_table_entry_t client_properties_entries[4];
    amqp_table_t client_properties_table;

    amqp_table_entry_t custom_properties_entries[2];
    amqp_table_t custom_properties_table;

    amqp_connection_resource *resource;

    /* Allocate space for the connection resource */
    resource = (amqp_connection_resource *) pecalloc(1, sizeof(amqp_connection_resource), persistent);

    /* Create the connection */
    resource->connection_state = amqp_new_connection();

    /* Create socket object */
    if (params->cacert) {
        resource->socket = amqp_ssl_socket_new(resource->connection_state);

        if (!resource->socket) {
            zend_throw_exception(
                amqp_connection_exception_class_entry,
                "Socket error: could not create SSL socket.",
                0
            );

            return NULL;
        }


        if (amqp_ssl_socket_set_cacert(resource->socket, params->cacert) != AMQP_STATUS_OK) {
            zend_throw_exception(
                amqp_connection_exception_class_entry,
                "Socket error: could not set CA certificate.",
                0
            );
            connection_resource_destructor(resource, persistent);

            return NULL;
        }

#if AMQP_VERSION_MAJOR * 100 + AMQP_VERSION_MINOR * 10 + AMQP_VERSION_PATCH >= 80
        amqp_ssl_socket_set_verify_peer(resource->socket, params->verify);
        amqp_ssl_socket_set_verify_hostname(resource->socket, params->verify);
#else
        amqp_ssl_socket_set_verify(resource->socket, params->verify);
#endif

        if (params->cert && params->key) {
            int client_cert_result = amqp_ssl_socket_set_key(resource->socket, params->cert, params->key);
            if (client_cert_result != AMQP_STATUS_OK) {
                zend_throw_exception_ex(
                    amqp_connection_exception_class_entry,
                    0,
                    "Socket error: could not set client cert, %s",
                    amqp_error_string2(client_cert_result)
                );
                connection_resource_destructor(resource, persistent);

                return NULL;
            }
        }

    } else {
        resource->socket = amqp_tcp_socket_new(resource->connection_state);

        if (!resource->socket) {
            zend_throw_exception(amqp_connection_exception_class_entry, "Socket error: could not create socket.", 0);

            return NULL;
        }
    }

    if (params->connect_timeout > 0) {
        tv.tv_sec = (long int) params->connect_timeout;
        tv.tv_usec = (long int) ((params->connect_timeout - tv.tv_sec) * 1000000);
    } else {
        tv_ptr = NULL;
    }

    /* Try to connect and verify that no error occurred */
    int connection_result = amqp_socket_open_noblock(resource->socket, params->host, params->port, tv_ptr);
    if (connection_result != AMQP_STATUS_OK) {

        zend_throw_exception_ex(
            amqp_connection_exception_class_entry,
            0,
            "Socket error: could not connect to host, %s",
            amqp_error_string2(connection_result)
        );
        connection_resource_destructor(resource, persistent);

        return NULL;
    }

    if (!php_amqp_set_resource_read_timeout(resource, params->read_timeout)) {
        connection_resource_destructor(resource, persistent);
        return NULL;
    }

    if (!php_amqp_set_resource_write_timeout(resource, params->write_timeout)) {
        connection_resource_destructor(resource, persistent);
        return NULL;
    }

    if (!php_amqp_set_resource_rpc_timeout(resource, params->rpc_timeout)) {
        connection_resource_destructor(resource, persistent);
        return NULL;
    }

    std_datetime = php_std_date(time(NULL));

    client_properties_entries[0].key = amqp_cstring_bytes("type");
    client_properties_entries[0].value.kind = AMQP_FIELD_KIND_UTF8;
    client_properties_entries[0].value.value.bytes = amqp_cstring_bytes("php-amqp extension");

    client_properties_entries[1].key = amqp_cstring_bytes("version");
    client_properties_entries[1].value.kind = AMQP_FIELD_KIND_UTF8;
    client_properties_entries[1].value.value.bytes = amqp_cstring_bytes(PHP_AMQP_VERSION);

    client_properties_entries[2].key = amqp_cstring_bytes("connection type");
    client_properties_entries[2].value.kind = AMQP_FIELD_KIND_UTF8;
    client_properties_entries[2].value.value.bytes = amqp_cstring_bytes(persistent ? "persistent" : "transient");

    client_properties_entries[3].key = amqp_cstring_bytes("connection started");
    client_properties_entries[3].value.kind = AMQP_FIELD_KIND_UTF8;
    client_properties_entries[3].value.value.bytes = amqp_cstring_bytes(std_datetime);

    client_properties_table.entries = client_properties_entries;
    client_properties_table.num_entries = sizeof(client_properties_entries) / sizeof(amqp_table_entry_t);

    custom_properties_entries[0].key = amqp_cstring_bytes("client");
    custom_properties_entries[0].value.kind = AMQP_FIELD_KIND_TABLE;
    custom_properties_entries[0].value.value.table = client_properties_table;


    if (params->connection_name) {
        custom_properties_entries[1].key = amqp_cstring_bytes("connection_name");
        custom_properties_entries[1].value.kind = AMQP_FIELD_KIND_UTF8;
        custom_properties_entries[1].value.value.bytes = amqp_cstring_bytes(params->connection_name);
    }

    custom_properties_table.entries = custom_properties_entries;
    custom_properties_table.num_entries = params->connection_name ? 2 : 1;

    /* We can assume that connection established here but it is not true, real handshake goes during login */

    assert(params->frame_max > 0);

    amqp_rpc_reply_t res = amqp_login_with_properties(
        resource->connection_state,
        params->vhost,
        params->channel_max,
        params->frame_max,
        params->heartbeat,
        &custom_properties_table,
        params->sasl_method,
        params->login,
        params->password
    );

    efree(std_datetime);

    if (AMQP_RESPONSE_NORMAL != res.reply_type) {
        char *message = NULL, *long_message = NULL;

        php_amqp_connection_resource_error(res, &message, resource, 0);

        spprintf(&long_message, 0, "%s - Potential login failure.", message);
        zend_throw_exception(amqp_connection_exception_class_entry, long_message, PHP_AMQP_G(error_code));

        efree(message);
        efree(long_message);

        /* https://www.rabbitmq.com/resources/specs/amqp0-9-1.pdf
		 *
		 * 2.2.4 The Connection Class:
		 * ... a peer that detects an error MUST close the socket without sending any further data.
		 *
		 * 4.10.2 Denial of Service Attacks:
		 * ... The general response to any exceptional condition in the connection negotiation is to pause that connection
		 * (presumably a thread) for a period of several seconds and then to close the network connection. This
		 * includes syntax errors, over-sized data, and failed attempts to authenticate.
		 */
        connection_resource_destructor(resource, persistent);
        return NULL;
    }

    /* Allocate space for the channel slots in the ring buffer */
    resource->max_slots = (amqp_channel_t) amqp_get_channel_max(resource->connection_state);
    assert(resource->max_slots > 0);

    resource->slots =
        (amqp_channel_resource **) pecalloc(resource->max_slots + 1, sizeof(amqp_channel_object *), persistent);

    resource->is_connected = '\1';

    return resource;
}

ZEND_RSRC_DTOR_FUNC(amqp_connection_resource_dtor_persistent)
{
    amqp_connection_resource *resource = (amqp_connection_resource *) res->ptr;

    connection_resource_destructor(resource, 1);
}

ZEND_RSRC_DTOR_FUNC(amqp_connection_resource_dtor)
{
    amqp_connection_resource *resource = (amqp_connection_resource *) res->ptr;

    connection_resource_destructor(resource, 0);
}

static void connection_resource_destructor(amqp_connection_resource *resource, int persistent)
{
    assert(resource != NULL);

#ifndef PHP_WIN32
    void *old_handler;

    /*
	If we are trying to close the connection and the connection already closed, it will throw
	SIGPIPE, which is fine, so ignore all SIGPIPES
	*/

    /* Start ignoring SIGPIPE */
    old_handler = signal(SIGPIPE, SIG_IGN);
#endif

    if (resource->parent) {
        resource->parent->connection_resource = NULL;
    }

    if (resource->slots) {
        php_amqp_prepare_for_disconnect(resource);

        pefree(resource->slots, persistent);
        resource->slots = NULL;
    }

    /* connection may be closed in case of previous failure */
    if (resource->is_connected) {
        amqp_connection_close(resource->connection_state, AMQP_REPLY_SUCCESS);
    }

    amqp_destroy_connection(resource->connection_state);

#ifndef PHP_WIN32
    /* End ignoring of SIGPIPEs */
    signal(SIGPIPE, old_handler);
#endif

    pefree(resource, persistent);
}

void php_amqp_prepare_for_disconnect(amqp_connection_resource *resource)
{
    if (resource == NULL) {
        return;
    }

    if (resource->slots != NULL) {
        /* NOTE: when we have persistent connection we do not move channels between php requests
		 *       due to current php-amqp extension limitation in AMQPChannel where __construct == channel.open AMQP method call
		 *       and __destruct = channel.close AMQP method call
		 */

        /* Clean up old memory allocations which are now invalid (new connection) */
        amqp_channel_t slot;

        for (slot = 0; slot < resource->max_slots; slot++) {
            if (resource->slots[slot] != 0) {
                php_amqp_close_channel(resource->slots[slot], 0);
            }
        }
    }

    /* If it's persistent connection do not destroy connection resource (this keep connection alive) */
    if (resource->is_persistent) {
        /* Cleanup buffers to reduce memory usage in idle mode */
        amqp_maybe_release_buffers(resource->connection_state);
    }

    return;
}