/* (C) 2021 by sysmocom s.f.m.c. GmbH * 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 . * */ #include #include #include #include #include #define LOGPPMGW(pool_member, level, fmt, args...) \ LOGP(DLMGCP, level, "MGW-pool(%s) " fmt, mgcp_client_pool_member_name(pool_member), ## args) /* Get a human readable name for a given pool member. */ const char *mgcp_client_pool_member_name(const struct mgcp_client_pool_member *pool_member) { const struct mgcp_client *mpcp_client; struct mgcp_client mpcp_client_dummy; static char name[512]; const char *description; if (!pool_member) return "(null)"; /* It is not guranteed that a pool_member has an MGCP client. The client may not yet be initialized or the * initalization may have been failed. In this case we will generate a dummy MGCP client to work with. */ if (!pool_member->client) { memcpy(&mpcp_client_dummy.actual, &pool_member->conf, sizeof(mpcp_client_dummy.actual)); mpcp_client = &mpcp_client_dummy; } else { mpcp_client = pool_member->client; } description = mgcp_client_name(mpcp_client); snprintf(name, sizeof(name), "%d:%s", pool_member->nr, description); return name; } /*! 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->member_list); 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->member_list, list) { /* Initialize client */ pool_member->client = mgcp_client_init(pool_member, &pool_member->conf); if (!pool_member->client) { LOGPPMGW(pool_member, LOGL_ERROR, "MGCP client initialization failed\n"); 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)) { LOGPPMGW(pool_member, LOGL_ERROR, "MGCP client connect failed at (%s:%u)\n", 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; } /*! Lookup the selected MGCP client config by its reference number */ struct mgcp_client_pool_member *mgcp_client_pool_find_member_by_nr(struct mgcp_client_pool *pool, unsigned int nr) { struct mgcp_client_pool_member *pool_member; llist_for_each_entry(pool_member, &pool->member_list, list) { if (pool_member->nr == nr) return pool_member; } return NULL; } /* 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 = 0; llist_for_each_entry(pool_member, &pool->member_list, list) { n_pool_members++; 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 { LOGPPMGW(pool_member, LOGL_DEBUG, "%s -- MGW %u is unusable (blocked=%u, cli=%u)\n", __func__, pool_member->nr, pool_member->blocked, !!pool_member->client); } } if (pool_member_picked) { LOGPPMGW(pool_member_picked, 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->member_list) && pool->mgcp_client_single) { LOGP(DLMGCP, LOGL_DEBUG, "MGW pool is empty -- using (single) MGW %s\n", mgcp_client_name(pool->mgcp_client_single)); return pool->mgcp_client_single; } /* Abort when the pool is empty */ if (llist_empty(&pool->member_list)) { 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->member_list, list) { if (pool_member->client == mgcp_client) { if (pool_member->refcount == 0) { LOGPPMGW(pool_member, LOGL_ERROR, "MGW pool member has invalid refcount\n"); return; } pool_member->refcount--; } } } /*************************** * mgcp_client_pool_member: ***************************/ /*! Allocate an mgcp_client_pool_member. * \param[in] pool MGCP client pool descriptor. * \param[in] nr Reference number of the pool member. */ struct mgcp_client_pool_member *mgcp_client_pool_member_alloc(struct mgcp_client_pool *pool, unsigned int nr) { struct mgcp_client_pool_member *pool_member; pool_member = talloc_zero(pool, struct mgcp_client_pool_member); OSMO_ASSERT(pool_member); mgcp_client_conf_init(&pool_member->conf); pool_member->nr = nr; llist_add_tail(&pool_member->list, &pool->member_list); return pool_member; } /*! Free an mgcp_client_pool_member allocated through mgcp_client_pool_member_alloc(). * \param[in] pool_member MGCP client pool descriptor. * * It also frees the associated MGCP client if present. */ void mgcp_client_pool_member_free(struct mgcp_client_pool_member *pool_member) { llist_del(&pool_member->list); if (pool_member->client) { mgcp_client_disconnect(pool_member->client); talloc_free(pool_member->client); } talloc_free(pool_member); }