1 /* MIT License
2 *
3 * Copyright (c) 1998 Massachusetts Institute of Technology
4 * Copyright (c) The c-ares project and its contributors
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the next
14 * paragraph) shall be included in all copies or substantial portions of the
15 * Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23 * SOFTWARE.
24 *
25 * SPDX-License-Identifier: MIT
26 */
27
28 #include "ares_private.h"
29 #include <assert.h>
30
ares_requeue_queries(ares_conn_t * conn,ares_status_t requeue_status)31 static void ares_requeue_queries(ares_conn_t *conn,
32 ares_status_t requeue_status)
33 {
34 ares_query_t *query;
35 ares_timeval_t now;
36
37 ares_tvnow(&now);
38
39 while ((query = ares_llist_first_val(conn->queries_to_conn)) != NULL) {
40 ares_requeue_query(query, &now, requeue_status, ARES_TRUE, NULL, NULL);
41 }
42 }
43
ares_close_connection(ares_conn_t * conn,ares_status_t requeue_status)44 void ares_close_connection(ares_conn_t *conn, ares_status_t requeue_status)
45 {
46 ares_server_t *server = conn->server;
47 ares_channel_t *channel = server->channel;
48
49 /* Unlink */
50 ares_llist_node_claim(
51 ares_htable_asvp_get_direct(channel->connnode_by_socket, conn->fd));
52 ares_htable_asvp_remove(channel->connnode_by_socket, conn->fd);
53
54 if (conn->flags & ARES_CONN_FLAG_TCP) {
55 server->tcp_conn = NULL;
56 }
57
58 ares_buf_destroy(conn->in_buf);
59 ares_buf_destroy(conn->out_buf);
60
61 /* Requeue queries to other connections */
62 ares_requeue_queries(conn, requeue_status);
63
64 ares_llist_destroy(conn->queries_to_conn);
65
66 ares_conn_sock_state_cb_update(conn, ARES_CONN_STATE_NONE);
67
68 ares_socket_close(channel, conn->fd);
69
70 ares_free(conn);
71 }
72
ares_close_sockets(ares_server_t * server)73 void ares_close_sockets(ares_server_t *server)
74 {
75 ares_llist_node_t *node;
76
77 while ((node = ares_llist_node_first(server->connections)) != NULL) {
78 ares_conn_t *conn = ares_llist_node_val(node);
79 ares_close_connection(conn, ARES_SUCCESS);
80 }
81 }
82
ares_check_cleanup_conns(const ares_channel_t * channel)83 void ares_check_cleanup_conns(const ares_channel_t *channel)
84 {
85 ares_slist_node_t *snode;
86
87 if (channel == NULL) {
88 return; /* LCOV_EXCL_LINE: DefensiveCoding */
89 }
90
91 /* Iterate across each server */
92 for (snode = ares_slist_node_first(channel->servers); snode != NULL;
93 snode = ares_slist_node_next(snode)) {
94 ares_server_t *server = ares_slist_node_val(snode);
95 ares_llist_node_t *cnode;
96
97 /* Iterate across each connection */
98 cnode = ares_llist_node_first(server->connections);
99 while (cnode != NULL) {
100 ares_llist_node_t *next = ares_llist_node_next(cnode);
101 ares_conn_t *conn = ares_llist_node_val(cnode);
102 ares_bool_t do_cleanup = ARES_FALSE;
103 cnode = next;
104
105 /* Has connections, not eligible */
106 if (ares_llist_len(conn->queries_to_conn)) {
107 continue;
108 }
109
110 /* If we are configured not to stay open, close it out */
111 if (!(channel->flags & ARES_FLAG_STAYOPEN)) {
112 do_cleanup = ARES_TRUE;
113 }
114
115 /* If the associated server has failures, close it out. Resetting the
116 * connection (and specifically the source port number) can help resolve
117 * situations where packets are being dropped.
118 */
119 if (conn->server->consec_failures > 0) {
120 do_cleanup = ARES_TRUE;
121 }
122
123 /* If the udp connection hit its max queries, always close it */
124 if (!(conn->flags & ARES_CONN_FLAG_TCP) && channel->udp_max_queries > 0 &&
125 conn->total_queries >= channel->udp_max_queries) {
126 do_cleanup = ARES_TRUE;
127 }
128
129 if (!do_cleanup) {
130 continue;
131 }
132
133 /* Clean it up */
134 ares_close_connection(conn, ARES_SUCCESS);
135 }
136 }
137 }
138