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resolved: fallback to TCP if UDP fails
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1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
2
3 #pragma once
4
5 /***
6 This file is part of systemd.
7
8 Copyright 2014 Lennart Poettering
9
10 systemd is free software; you can redistribute it and/or modify it
11 under the terms of the GNU Lesser General Public License as published by
12 the Free Software Foundation; either version 2.1 of the License, or
13 (at your option) any later version.
14
15 systemd is distributed in the hope that it will be useful, but
16 WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 Lesser General Public License for more details.
19
20 You should have received a copy of the GNU Lesser General Public License
21 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 ***/
23
24 #include "in-addr-util.h"
25
26 typedef struct DnsServer DnsServer;
27
28 typedef enum DnsServerType {
29 DNS_SERVER_SYSTEM,
30 DNS_SERVER_FALLBACK,
31 DNS_SERVER_LINK,
32 } DnsServerType;
33
34 typedef enum DnsServerFeatureLevel {
35 DNS_SERVER_FEATURE_LEVEL_TCP,
36 DNS_SERVER_FEATURE_LEVEL_UDP,
37 _DNS_SERVER_FEATURE_LEVEL_MAX,
38 _DNS_SERVER_FEATURE_LEVEL_INVALID = -1
39 } DnsServerFeatureLevel;
40
41 #define DNS_SERVER_FEATURE_LEVEL_WORST 0
42 #define DNS_SERVER_FEATURE_LEVEL_BEST (_DNS_SERVER_FEATURE_LEVEL_MAX - 1)
43
44 const char* dns_server_feature_level_to_string(int i) _const_;
45 int dns_server_feature_level_from_string(const char *s) _pure_;
46
47 #include "resolved-link.h"
48 #include "resolved-manager.h"
49
50 struct DnsServer {
51 Manager *manager;
52
53 unsigned n_ref;
54
55 DnsServerType type;
56 Link *link;
57
58 int family;
59 union in_addr_union address;
60
61 usec_t resend_timeout;
62 usec_t max_rtt;
63
64 bool marked:1;
65 DnsServerFeatureLevel verified_features;
66 DnsServerFeatureLevel possible_features;
67 unsigned n_failed_attempts;
68 usec_t verified_usec;
69 usec_t features_grace_period_usec;
70
71 /* If linked is set, then this server appears in the servers linked list */
72 bool linked:1;
73 LIST_FIELDS(DnsServer, servers);
74 };
75
76 int dns_server_new(
77 Manager *m,
78 DnsServer **ret,
79 DnsServerType type,
80 Link *link,
81 int family,
82 const union in_addr_union *address);
83
84 DnsServer* dns_server_ref(DnsServer *s);
85 DnsServer* dns_server_unref(DnsServer *s);
86
87 void dns_server_unlink(DnsServer *s);
88 void dns_server_move_back_and_unmark(DnsServer *s);
89
90 void dns_server_packet_received(DnsServer *s, DnsServerFeatureLevel features, usec_t rtt);
91 void dns_server_packet_lost(DnsServer *s, DnsServerFeatureLevel features, usec_t usec);
92
93 DnsServer *dns_server_find(DnsServer *first, int family, const union in_addr_union *in_addr);
94
95 void dns_server_unlink_all(DnsServer *first);
96 void dns_server_unlink_marked(DnsServer *first);
97 void dns_server_mark_all(DnsServer *first);
98
99 DnsServer *manager_get_first_dns_server(Manager *m, DnsServerType t);
100
101 DnsServer *manager_set_dns_server(Manager *m, DnsServer *s);
102 DnsServer *manager_get_dns_server(Manager *m);
103 void manager_next_dns_server(Manager *m);
104
105 DEFINE_TRIVIAL_CLEANUP_FUNC(DnsServer*, dns_server_unref);
106
107 DnsServerFeatureLevel dns_server_possible_features(DnsServer *s);
108
109 extern const struct hash_ops dns_server_hash_ops;