src/bin/lttng-relayd/connection.cpp

   1 /*
   2  * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
   3  * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
   4  * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-only
   7  *
   8  */
   9
  10 #define _LGPL_SOURCE
  11 #include "connection.hpp"
  12 #include "stream.hpp"
  13 #include "viewer-session.hpp"
  14
  15 #include <common/common.hpp>
  16 #include <common/urcu.hpp>
  17
  18 #include <urcu/rculist.h>
  19
  20 bool connection_get(struct relay_connection *conn)
  21 {
  22         return urcu_ref_get_unless_zero(&conn->ref);
  23 }
  24
  25 struct relay_connection *connection_get_by_sock(struct lttng_ht *relay_connections_ht, int sock)
  26 {
  27         struct lttng_ht_node_ulong *node;
  28         struct lttng_ht_iter iter;
  29         struct relay_connection *conn = nullptr;
  30
  31         LTTNG_ASSERT(sock >= 0);
  32
  33         lttng::urcu::read_lock_guard read_lock;
  34         lttng_ht_lookup(relay_connections_ht, (void *) ((unsigned long) sock), &iter);
  35         node = lttng_ht_iter_get_node_ulong(&iter);
  36         if (!node) {
  37                 DBG2("Relay connection by sock %d not found", sock);
  38                 goto end;
  39         }
  40         conn = lttng::utils::container_of(node, &relay_connection::sock_n);
  41         if (!connection_get(conn)) {
  42                 conn = nullptr;
  43         }
  44 end:
  45         return conn;
  46 }
  47
  48 int connection_reset_protocol_state(struct relay_connection *connection)
  49 {
  50         int ret = 0;
  51
  52         switch (connection->type) {
  53         case RELAY_DATA:
  54                 connection->protocol.data.state_id = DATA_CONNECTION_STATE_RECEIVE_HEADER;
  55                 memset(&connection->protocol.data.state.receive_header,
  56                        0,
  57                        sizeof(connection->protocol.data.state.receive_header));
  58                 connection->protocol.data.state.receive_header.left_to_receive =
  59                         sizeof(struct lttcomm_relayd_data_hdr);
  60                 break;
  61         case RELAY_CONTROL:
  62                 connection->protocol.ctrl.state_id = CTRL_CONNECTION_STATE_RECEIVE_HEADER;
  63                 memset(&connection->protocol.ctrl.state.receive_header,
  64                        0,
  65                        sizeof(connection->protocol.ctrl.state.receive_header));
  66                 connection->protocol.data.state.receive_header.left_to_receive =
  67                         sizeof(struct lttcomm_relayd_hdr);
  68                 ret = lttng_dynamic_buffer_set_size(&connection->protocol.ctrl.reception_buffer,
  69                                                     sizeof(struct lttcomm_relayd_hdr));
  70                 if (ret) {
  71                         ERR("Failed to reinitialize control connection reception buffer size to %zu bytes.",
  72                             sizeof(struct lttcomm_relayd_hdr));
  73                         goto end;
  74                 }
  75                 break;
  76         default:
  77                 goto end;
  78         }
  79         DBG("Reset communication state of relay connection (fd = %i)", connection->sock->fd);
  80 end:
  81         return ret;
  82 }
  83
  84 struct relay_connection *connection_create(struct lttcomm_sock *sock, enum connection_type type)
  85 {
  86         struct relay_connection *conn;
  87
  88         conn = zmalloc<relay_connection>();
  89         if (!conn) {
  90                 PERROR("zmalloc relay connection");
  91                 goto end;
  92         }
  93         urcu_ref_init(&conn->ref);
  94         conn->type = type;
  95         conn->sock = sock;
  96         lttng_ht_node_init_ulong(&conn->sock_n, (unsigned long) conn->sock->fd);
  97         if (conn->type == RELAY_CONTROL) {
  98                 lttng_dynamic_buffer_init(&conn->protocol.ctrl.reception_buffer);
  99         }
 100         connection_reset_protocol_state(conn);
 101 end:
 102         return conn;
 103 }
 104
 105 static void rcu_free_connection(struct rcu_head *head)
 106 {
 107         struct relay_connection *conn =
 108                 lttng::utils::container_of(head, &relay_connection::rcu_node);
 109
 110         lttcomm_destroy_sock(conn->sock);
 111         if (conn->viewer_session) {
 112                 viewer_session_destroy(conn->viewer_session);
 113                 conn->viewer_session = nullptr;
 114         }
 115         if (conn->type == RELAY_CONTROL) {
 116                 lttng_dynamic_buffer_reset(&conn->protocol.ctrl.reception_buffer);
 117         }
 118         free(conn);
 119 }
 120
 121 static void destroy_connection(struct relay_connection *conn)
 122 {
 123         call_rcu(&conn->rcu_node, rcu_free_connection);
 124 }
 125
 126 static void connection_release(struct urcu_ref *ref)
 127 {
 128         struct relay_connection *conn = lttng::utils::container_of(ref, &relay_connection::ref);
 129
 130         if (conn->in_socket_ht) {
 131                 struct lttng_ht_iter iter;
 132                 int ret;
 133
 134                 iter.iter.node = &conn->sock_n.node;
 135                 ret = lttng_ht_del(conn->socket_ht, &iter);
 136                 LTTNG_ASSERT(!ret);
 137         }
 138
 139         if (conn->session) {
 140                 if (session_close(conn->session)) {
 141                         ERR("session_close");
 142                 }
 143                 conn->session = nullptr;
 144         }
 145         if (conn->viewer_session) {
 146                 viewer_session_close(conn->viewer_session);
 147         }
 148         destroy_connection(conn);
 149 }
 150
 151 void connection_put(struct relay_connection *conn)
 152 {
 153         lttng::urcu::read_lock_guard read_lock;
 154         urcu_ref_put(&conn->ref, connection_release);
 155 }
 156
 157 void connection_ht_add(struct lttng_ht *relay_connections_ht, struct relay_connection *conn)
 158 {
 159         LTTNG_ASSERT(!conn->in_socket_ht);
 160         lttng_ht_add_unique_ulong(relay_connections_ht, &conn->sock_n);
 161         conn->in_socket_ht = true;
 162         conn->socket_ht = relay_connections_ht;
 163 }
 164
 165 int connection_set_session(struct relay_connection *conn, struct relay_session *session)
 166 {
 167         int ret = 0;
 168
 169         LTTNG_ASSERT(conn);
 170         LTTNG_ASSERT(session);
 171         LTTNG_ASSERT(!conn->session);
 172
 173         if (connection_get(conn)) {
 174                 if (session_get(session)) {
 175                         conn->session = session;
 176                 } else {
 177                         ERR("Failed to get session reference in connection_set_session()");
 178                         ret = -1;
 179                 }
 180                 connection_put(conn);
 181         } else {
 182                 ERR("Failed to get connection reference in connection_set_session()");
 183                 ret = -1;
 184         }
 185         return ret;
 186 }