src/bin/lttng-relayd/connection.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License, version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _LGPL_SOURCE
  21 #include <common/common.h>
  22 #include <urcu/rculist.h>
  23
  24 #include "connection.h"
  25 #include "stream.h"
  26 #include "viewer-session.h"
  27
  28 bool connection_get(struct relay_connection *conn)
  29 {
  30         bool has_ref = false;
  31
  32         pthread_mutex_lock(&conn->reflock);
  33         if (conn->ref.refcount != 0) {
  34                 has_ref = true;
  35                 urcu_ref_get(&conn->ref);
  36         }
  37         pthread_mutex_unlock(&conn->reflock);
  38
  39         return has_ref;
  40 }
  41
  42 struct relay_connection *connection_get_by_sock(struct lttng_ht *relay_connections_ht,
  43                 int sock)
  44 {
  45         struct lttng_ht_node_ulong *node;
  46         struct lttng_ht_iter iter;
  47         struct relay_connection *conn = NULL;
  48
  49         assert(sock >= 0);
  50
  51         rcu_read_lock();
  52         lttng_ht_lookup(relay_connections_ht, (void *)((unsigned long) sock),
  53                         &iter);
  54         node = lttng_ht_iter_get_node_ulong(&iter);
  55         if (!node) {
  56                 DBG2("Relay connection by sock %d not found", sock);
  57                 goto end;
  58         }
  59         conn = caa_container_of(node, struct relay_connection, sock_n);
  60         if (!connection_get(conn)) {
  61                 conn = NULL;
  62         }
  63 end:
  64         rcu_read_unlock();
  65         return conn;
  66 }
  67
  68 int connection_reset_protocol_state(struct relay_connection *connection)
  69 {
  70         int ret = 0;
  71
  72         switch (connection->type) {
  73         case RELAY_DATA:
  74                 connection->protocol.data.state_id =
  75                                 DATA_CONNECTION_STATE_RECEIVE_HEADER;
  76                 memset(&connection->protocol.data.state.receive_header,
  77                                 0,
  78                                 sizeof(connection->protocol.data.state.receive_header));
  79                 connection->protocol.data.state.receive_header.left_to_receive =
  80                                 sizeof(struct lttcomm_relayd_data_hdr);
  81                 break;
  82         case RELAY_CONTROL:
  83                 connection->protocol.ctrl.state_id =
  84                                 CTRL_CONNECTION_STATE_RECEIVE_HEADER;
  85                 memset(&connection->protocol.ctrl.state.receive_header,
  86                                 0,
  87                                 sizeof(connection->protocol.ctrl.state.receive_header));
  88                 connection->protocol.data.state.receive_header.left_to_receive =
  89                                 sizeof(struct lttcomm_relayd_hdr);
  90                 ret = lttng_dynamic_buffer_set_size(
  91                                 &connection->protocol.ctrl.reception_buffer,
  92                                 sizeof(struct lttcomm_relayd_hdr));
  93                 if (ret) {
  94                         ERR("Failed to reinitialize control connection reception buffer size to %zu bytes.", sizeof(struct lttcomm_relayd_hdr));
  95                         goto end;
  96                 }
  97                 break;
  98         default:
  99                 goto end;
 100         }
 101         DBG("Reset communication state of relay connection (fd = %i)",
 102                         connection->sock->fd);
 103 end:
 104         return ret;
 105 }
 106
 107 struct relay_connection *connection_create(struct lttcomm_sock *sock,
 108                 enum connection_type type)
 109 {
 110         struct relay_connection *conn;
 111
 112         conn = zmalloc(sizeof(*conn));
 113         if (!conn) {
 114                 PERROR("zmalloc relay connection");
 115                 goto end;
 116         }
 117         pthread_mutex_init(&conn->reflock, NULL);
 118         urcu_ref_init(&conn->ref);
 119         conn->type = type;
 120         conn->sock = sock;
 121         lttng_ht_node_init_ulong(&conn->sock_n, (unsigned long) conn->sock->fd);
 122         if (conn->type == RELAY_CONTROL) {
 123                 lttng_dynamic_buffer_init(&conn->protocol.ctrl.reception_buffer);
 124         }
 125         connection_reset_protocol_state(conn);
 126 end:
 127         return conn;
 128 }
 129
 130 static void rcu_free_connection(struct rcu_head *head)
 131 {
 132         struct relay_connection *conn =
 133                 caa_container_of(head, struct relay_connection, rcu_node);
 134
 135         lttcomm_destroy_sock(conn->sock);
 136         if (conn->viewer_session) {
 137                 viewer_session_destroy(conn->viewer_session);
 138                 conn->viewer_session = NULL;
 139         }
 140         free(conn);
 141 }
 142
 143 static void destroy_connection(struct relay_connection *conn)
 144 {
 145         call_rcu(&conn->rcu_node, rcu_free_connection);
 146 }
 147
 148 static void connection_release(struct urcu_ref *ref)
 149 {
 150         struct relay_connection *conn =
 151                 caa_container_of(ref, struct relay_connection, ref);
 152
 153         if (conn->in_socket_ht) {
 154                 struct lttng_ht_iter iter;
 155                 int ret;
 156
 157                 iter.iter.node = &conn->sock_n.node;
 158                 ret = lttng_ht_del(conn->socket_ht, &iter);
 159                 assert(!ret);
 160         }
 161
 162         if (conn->session) {
 163                 if (session_close(conn->session)) {
 164                         ERR("session_close");
 165                 }
 166                 conn->session = NULL;
 167         }
 168         if (conn->viewer_session) {
 169                 viewer_session_close(conn->viewer_session);
 170         }
 171         destroy_connection(conn);
 172 }
 173
 174 void connection_put(struct relay_connection *conn)
 175 {
 176         rcu_read_lock();
 177         pthread_mutex_lock(&conn->reflock);
 178         urcu_ref_put(&conn->ref, connection_release);
 179         pthread_mutex_unlock(&conn->reflock);
 180         rcu_read_unlock();
 181 }
 182
 183 void connection_ht_add(struct lttng_ht *relay_connections_ht,
 184                 struct relay_connection *conn)
 185 {
 186         assert(!conn->in_socket_ht);
 187         lttng_ht_add_unique_ulong(relay_connections_ht, &conn->sock_n);
 188         conn->in_socket_ht = 1;
 189         conn->socket_ht = relay_connections_ht;
 190 }
 191
 192 int connection_set_session(struct relay_connection *conn,
 193                 struct relay_session *session)
 194 {
 195         int ret = 0;
 196
 197         assert(conn);
 198         assert(session);
 199         assert(!conn->session);
 200
 201         if (connection_get(conn)) {
 202                 if (session_get(session)) {
 203                         conn->session = session;
 204                 } else {
 205                         ERR("Failed to get session reference in connection_set_session()");
 206                         ret = -1;
 207                 }
 208                 connection_put(conn);
 209         } else {
 210                 ERR("Failed to get connection reference in connection_set_session()");
 211                 ret = -1;
 212         }
 213         return ret;
 214 }