switch_limit.c

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/*
 * FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 * Copyright (C) 2005-2014, Anthony Minessale II <anthm@freeswitch.org>
 *
 * Version: MPL 1.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 *
 * The Initial Developer of the Original Code is
 * Anthony Minessale II <anthm@freeswitch.org>
 * Portions created by the Initial Developer are Copyright (C)
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Rupa Schomaker <rupa@rupa.com>
 *
 * switch_limit.c Limit support
 *
 */

#include <switch.h>
#include <switch_module_interfaces.h> /* this is odd VS 2008 Express requires this- include order problem?? */

static switch_limit_interface_t *get_backend(const char *backend) {
        switch_limit_interface_t *limit = NULL;

        if (!backend) {
                return NULL;
        }

        if (!(limit = switch_loadable_module_get_limit_interface(backend))) {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_DEBUG, "Unable to locate limit backend: %s\n", backend);
        }

        return limit;
}

static void release_backend(switch_limit_interface_t *limit) {
        UNPROTECT_INTERFACE(limit);
}

SWITCH_DECLARE(void) switch_limit_init(switch_memory_pool_t *pool) {
        if (switch_event_reserve_subclass(LIMIT_EVENT_USAGE) != SWITCH_STATUS_SUCCESS) {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Couldn't register event subclass \"%s\"", LIMIT_EVENT_USAGE);
        }
}


SWITCH_DECLARE(void) switch_limit_fire_event(const char *backend, const char *realm, const char *key, uint32_t usage, uint32_t rate, uint32_t max, uint32_t ratemax)
{
        switch_event_t *event;

        if (switch_event_create_subclass(&event, SWITCH_EVENT_CUSTOM, LIMIT_EVENT_USAGE) == SWITCH_STATUS_SUCCESS) {
                switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, "backend", backend);
                switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, "realm", realm);
                switch_event_add_header_string(event, SWITCH_STACK_BOTTOM, "key", key);
                switch_event_add_header(event, SWITCH_STACK_BOTTOM, "usage", "%d", usage);
                switch_event_add_header(event, SWITCH_STACK_BOTTOM, "rate", "%d", rate);
                switch_event_add_header(event, SWITCH_STACK_BOTTOM, "max", "%d", max);
                switch_event_add_header(event, SWITCH_STACK_BOTTOM, "ratemax", "%d", ratemax);
                switch_event_fire(&event);
        }
}

static switch_status_t limit_state_handler(switch_core_session_t *session)
{
        switch_channel_t *channel = switch_core_session_get_channel(session);
        switch_channel_state_t state = switch_channel_get_state(channel);
        const char *vval = switch_channel_get_variable(channel, LIMIT_IGNORE_TRANSFER_VARIABLE);
        const char *backendlist = switch_channel_get_variable(channel, LIMIT_BACKEND_VARIABLE);

        if (zstr(backendlist)) {
                switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG, "Unset limit backendlist!\n");
                return SWITCH_STATUS_SUCCESS;
        }

        if (state >= CS_HANGUP || (state == CS_ROUTING && !switch_true(vval))) {
                int argc = 0;
                char *argv[6] = { 0 };
                char *mydata = strdup(backendlist);
                int x;

                argc = switch_separate_string(mydata, ',', argv, (sizeof(argv) / sizeof(argv[0])));
                for (x = 0; x < argc; x++) {
                        switch_limit_release(argv[x], session, NULL, NULL);
                }
                switch_core_event_hook_remove_state_change(session, limit_state_handler);
                /* Remove limit_backend variable so we register another hook if limit is called again */
                switch_channel_set_variable(channel, LIMIT_BACKEND_VARIABLE, NULL);

                free(mydata);
        }

        return SWITCH_STATUS_SUCCESS;
}


SWITCH_DECLARE(switch_status_t) switch_limit_incr(const char *backend, switch_core_session_t *session, const char *realm, const char *resource, const int max, const int interval) {
        switch_limit_interface_t *limit = NULL;
        switch_channel_t *channel = NULL;
        int status = SWITCH_STATUS_SUCCESS;

        assert(session);

        channel = switch_core_session_get_channel(session);

        /* locate impl, call appropriate func */
        if (!(limit = get_backend(backend))) {
                switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_ERROR, "Limit subsystem %s not found!\n", backend);
                switch_goto_status(SWITCH_STATUS_GENERR, end);
        }

        switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG, "incr called: %s_%s max:%d, interval:%d\n",
                                          realm, resource, max, interval);

        if ((status = limit->incr(session, realm, resource, max, interval)) == SWITCH_STATUS_SUCCESS) {
                /* race condition? what if another leg is doing the same thing? */
                const char *existing = switch_channel_get_variable(channel, LIMIT_BACKEND_VARIABLE);
                if (existing) {
                        if (!strstr(existing, backend)) {
                                switch_channel_set_variable_printf(channel, LIMIT_BACKEND_VARIABLE, "%s,%s", existing, backend);
                        }
                } else {
                        switch_channel_set_variable(channel, LIMIT_BACKEND_VARIABLE, backend);
                        switch_core_event_hook_add_state_change(session, limit_state_handler);
                }
        }

        release_backend(limit);

end:
        return status;
}

SWITCH_DECLARE(switch_status_t) switch_limit_release(const char *backend, switch_core_session_t *session, const char *realm, const char *resource) {
        switch_limit_interface_t *limit = NULL;
        int status = SWITCH_STATUS_SUCCESS;

        /* locate impl, call appropriate func */
        if (!(limit = get_backend(backend))) {
                switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_ERROR, "Limit subsystem %s not found!\n", backend);
                switch_goto_status(SWITCH_STATUS_GENERR, end);
        }

        status = limit->release(session, realm, resource);

end:
        release_backend(limit);
        return status;
}

SWITCH_DECLARE(int) switch_limit_usage(const char *backend, const char *realm, const char *resource, uint32_t *rcount) {
        switch_limit_interface_t *limit = NULL;
        int usage = 0;

        /* locate impl, call appropriate func */
        if (!(limit = get_backend(backend))) {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Limit subsystem %s not found!\n", backend);
                goto end;
        }

        usage = limit->usage(realm, resource, rcount);

end:
        release_backend(limit);
        return usage;
}

SWITCH_DECLARE(switch_status_t) switch_limit_reset(const char *backend) {
        switch_limit_interface_t *limit = NULL;
        int status = SWITCH_STATUS_SUCCESS;

        /* locate impl, call appropriate func */
        if (!(limit = get_backend(backend))) {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Limit subsystem %s not found!\n", backend);
                switch_goto_status(SWITCH_STATUS_GENERR, end);
        }

        status = limit->reset();

end:
        release_backend(limit);
        return status;
}

SWITCH_DECLARE(switch_status_t) switch_limit_interval_reset(const char *backend, const char *realm, const char *resource) {
        switch_limit_interface_t *limit = NULL;
        int status = SWITCH_STATUS_SUCCESS;

        /* locate impl, call appropriate func */
        if (!(limit = get_backend(backend))) {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Limit subsystem %s not found!\n", backend);
                switch_goto_status(SWITCH_STATUS_GENERR, end);
        }

        if (!limit->interval_reset) {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Limit subsystem %s does not implement interval_reset!\n", backend);
                switch_goto_status(SWITCH_STATUS_GENERR, end);
        }

        status = limit->interval_reset(realm, resource);

end:
        release_backend(limit);
        return status;
}

SWITCH_DECLARE(char *) switch_limit_status(const char *backend) {
        switch_limit_interface_t *limit = NULL;
        char *status = NULL;

        /* locate impl, call appropriate func */
        if (!(limit = get_backend(backend))) {
                switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Limit subsystem %s not found!\n", backend);
                switch_goto_status(strdup("-ERR"), end);
        }

        status = limit->status();

end:
        release_backend(limit);
        return status;
}

/* For Emacs:
 * Local Variables:
 * mode:c
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 * c-basic-offset:4
 * End:
 * For VIM:
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 */