| /* (C) 2021 by sysmocom s.f.m.c. GmbH <info@sysmocom.de> |
| * All Rights Reserved |
| * |
| * Author: Philipp Maier |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| * |
| */ |
| |
| #include <osmocom/mgcp_client/mgcp_client.h> |
| #include <osmocom/mgcp_client/mgcp_client_internal.h> |
| #include <osmocom/mgcp_client/mgcp_client_pool_internal.h> |
| #include <osmocom/mgcp_client/mgcp_client_pool.h> |
| #include <stddef.h> |
| |
| /*! Allocate MGCP client pool. This is called once on startup and before the pool is used with |
| * mgcp_client_pool_vty_init(). Since the pool is linked with the VTY it must exist througout the entire runtime. |
| * \param[in] talloc_ctx talloc context. */ |
| struct mgcp_client_pool *mgcp_client_pool_alloc(void *talloc_ctx) |
| { |
| struct mgcp_client_pool *pool; |
| |
| pool = talloc_zero(talloc_ctx, struct mgcp_client_pool); |
| if (!pool) |
| return NULL; |
| |
| INIT_LLIST_HEAD(&pool->pool); |
| |
| return pool; |
| } |
| |
| /*! Initialize and connect an mcgp client pool. |
| * \param[in,out] mgcp MGCP client pool descriptor. |
| * \returns number of successfully initialized pool members. */ |
| unsigned int mgcp_client_pool_connect(struct mgcp_client_pool *pool) |
| { |
| struct mgcp_client_pool_member *pool_member; |
| unsigned int pool_members_initialized = 0; |
| |
| llist_for_each_entry(pool_member, &pool->pool, list) { |
| |
| /* Initialize client */ |
| pool_member->client = mgcp_client_init(pool_member, &pool_member->conf); |
| if (!pool_member->client) { |
| LOGP(DLMGCP, LOGL_ERROR, "MGW %u initialization failed\n", pool_member->nr); |
| continue; |
| } |
| |
| /* Set backpointer so that we can detect later that this MGCP client is managed |
| * by this pool. */ |
| pool_member->client->pool = pool; |
| |
| /* Connect client */ |
| if (mgcp_client_connect2(pool_member->client, 0)) { |
| LOGP(DLMGCP, LOGL_ERROR, "MGW %u connect failed at (%s:%u)\n", |
| pool_member->nr, pool_member->conf.remote_addr, pool_member->conf.remote_port); |
| talloc_free(pool_member->client); |
| pool_member->client = NULL; |
| continue; |
| } |
| |
| pool_members_initialized++; |
| } |
| |
| return pool_members_initialized; |
| } |
| |
| /*! register a single mgcp_client instance to the pool. |
| * \param[out] pool MGCP client pool descriptor. |
| * \param[in] mgcp MGCP client descriptor. */ |
| void mgcp_client_pool_register_single(struct mgcp_client_pool *pool, struct mgcp_client *mgcp_client) |
| { |
| /*! Some applications still support the non-pooled MGW VTY configuration variant provided by |
| * mgcp_client_vty_init(). If this is the case the mgcp_client instance created by mgcp_client_init() |
| * can be registered here so that it will appear as if it were part of the pool. When the user actively |
| * configures MGW pool members, the MGCP client registered here will be ignored. (The registration of |
| * multiple singe mgcp_client instances is not possible.) */ |
| pool->mgcp_client_single = mgcp_client; |
| } |
| |
| /* Not every pool member may have a functional MGCP client, we will run through the pool once until we meet a |
| * pool member that is suitable (has a client, is not blocked, has a low load). */ |
| static struct mgcp_client_pool_member *mgcp_client_pool_pick(struct mgcp_client_pool *pool) |
| { |
| struct mgcp_client_pool_member *pool_member; |
| struct mgcp_client_pool_member *pool_member_picked = NULL; |
| unsigned int n_pool_members = llist_count(&pool->pool); |
| |
| llist_for_each_entry(pool_member, &pool->pool, list) { |
| if (pool_member->blocked == false && pool_member->client) { |
| if (!pool_member_picked) |
| pool_member_picked = pool_member; |
| else if (pool_member_picked->refcount > pool_member->refcount) |
| pool_member_picked = pool_member; |
| } else { |
| LOGP(DLMGCP, LOGL_DEBUG, "MGW pool has %u members -- MGW %u is unusable\n", n_pool_members, |
| pool_member->nr); |
| } |
| } |
| |
| if (pool_member_picked) { |
| LOGP(DLMGCP, LOGL_DEBUG, "MGW pool has %u members -- using MGW %u (active calls: %u)\n", |
| n_pool_members, pool_member_picked->nr, pool_member_picked->refcount); |
| return pool_member_picked; |
| } |
| |
| LOGP(DLMGCP, LOGL_ERROR, |
| "MGW pool has %u members, but no functional MGW pool member found -- check configuration!\n", |
| n_pool_members); |
| |
| return NULL; |
| } |
| |
| /*! get an MGCP client from the pool (increment reference counter). |
| * \param[in,out] pool MGCP client pool descriptor. |
| * \returns MGCP client descriptor, NULL if no member was found (empty pool). */ |
| struct mgcp_client *mgcp_client_pool_get(struct mgcp_client_pool *pool) |
| { |
| struct mgcp_client_pool_member *pool_member; |
| |
| /*! When an MGCP client is taken from the pool it is still available for other calls. In fact only a reference |
| * counter is incremented to keep track on how many references to a specific MGCP client are currently used |
| * by the application code. */ |
| |
| /* When the pool is empty, return a single MGCP client if it is registered. */ |
| if (llist_empty(&pool->pool) && pool->mgcp_client_single) { |
| LOGP(DLMGCP, LOGL_DEBUG, "MGW pool is empty -- using (single) MGW\n"); |
| return pool->mgcp_client_single; |
| } |
| |
| /* Abort when the pool is empty */ |
| if (llist_empty(&pool->pool)) { |
| LOGP(DLMGCP, LOGL_ERROR, "MGW pool is empty -- no MGW available!\n"); |
| return NULL; |
| } |
| |
| /* Pick a suitable pool member */ |
| pool_member = mgcp_client_pool_pick(pool); |
| if (pool_member) { |
| pool_member->refcount++; |
| return pool_member->client; |
| } |
| |
| return NULL; |
| } |
| |
| /*! put an MGCP client back into the pool (decrement reference counter). |
| * \param[in,out] pool MGCP client pool descriptor. |
| * \param[in] mgcp MGCP client descriptor. |
| * |
| * This function is able to detect automatically to which pool the mgcp_client belongs. If the mgcp_client does |
| * not belong to a pool at all, the function call will have no effect. */ |
| void mgcp_client_pool_put(struct mgcp_client *mgcp_client) |
| { |
| struct mgcp_client_pool_member *pool_member; |
| struct mgcp_client_pool *pool; |
| |
| if (!mgcp_client) |
| return; |
| |
| if (mgcp_client->pool) |
| pool = mgcp_client->pool; |
| else |
| return; |
| |
| llist_for_each_entry(pool_member, &pool->pool, list) { |
| if (pool_member->client == mgcp_client) { |
| if (pool_member->refcount == 0) { |
| LOGP(DLMGCP, LOGL_ERROR, "MGW %u has invalid refcount\n", pool_member->nr); |
| return; |
| } |
| pool_member->refcount--; |
| } |
| } |
| } |