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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2014 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include "siphash24.h" | |
23 | ||
24 | #include "resolved-dns-server.h" | |
25 | ||
13d276d0 MP |
26 | /* After how much time to repeat classic DNS requests */ |
27 | #define DNS_TIMEOUT_MIN_USEC (500 * USEC_PER_MSEC) | |
28 | #define DNS_TIMEOUT_MAX_USEC (5 * USEC_PER_SEC) | |
29 | ||
5eef597e MP |
30 | int dns_server_new( |
31 | Manager *m, | |
32 | DnsServer **ret, | |
33 | DnsServerType type, | |
34 | Link *l, | |
35 | int family, | |
36 | const union in_addr_union *in_addr) { | |
37 | ||
38 | DnsServer *s, *tail; | |
39 | ||
40 | assert(m); | |
41 | assert((type == DNS_SERVER_LINK) == !!l); | |
42 | assert(in_addr); | |
43 | ||
44 | s = new0(DnsServer, 1); | |
45 | if (!s) | |
46 | return -ENOMEM; | |
47 | ||
7035cd9e | 48 | s->n_ref = 1; |
5eef597e MP |
49 | s->type = type; |
50 | s->family = family; | |
51 | s->address = *in_addr; | |
13d276d0 | 52 | s->resend_timeout = DNS_TIMEOUT_MIN_USEC; |
5eef597e MP |
53 | |
54 | if (type == DNS_SERVER_LINK) { | |
55 | LIST_FIND_TAIL(servers, l->dns_servers, tail); | |
56 | LIST_INSERT_AFTER(servers, l->dns_servers, tail, s); | |
57 | s->link = l; | |
58 | } else if (type == DNS_SERVER_SYSTEM) { | |
59 | LIST_FIND_TAIL(servers, m->dns_servers, tail); | |
60 | LIST_INSERT_AFTER(servers, m->dns_servers, tail, s); | |
61 | } else if (type == DNS_SERVER_FALLBACK) { | |
62 | LIST_FIND_TAIL(servers, m->fallback_dns_servers, tail); | |
63 | LIST_INSERT_AFTER(servers, m->fallback_dns_servers, tail, s); | |
64 | } else | |
65 | assert_not_reached("Unknown server type"); | |
66 | ||
67 | s->manager = m; | |
68 | ||
69 | /* A new DNS server that isn't fallback is added and the one | |
70 | * we used so far was a fallback one? Then let's try to pick | |
71 | * the new one */ | |
72 | if (type != DNS_SERVER_FALLBACK && | |
73 | m->current_dns_server && | |
74 | m->current_dns_server->type == DNS_SERVER_FALLBACK) | |
75 | manager_set_dns_server(m, NULL); | |
76 | ||
77 | if (ret) | |
78 | *ret = s; | |
79 | ||
80 | return 0; | |
81 | } | |
82 | ||
7035cd9e | 83 | DnsServer* dns_server_ref(DnsServer *s) { |
5eef597e MP |
84 | if (!s) |
85 | return NULL; | |
86 | ||
7035cd9e | 87 | assert(s->n_ref > 0); |
e3bff60a | 88 | |
7035cd9e | 89 | s->n_ref ++; |
e3bff60a | 90 | |
7035cd9e MP |
91 | return s; |
92 | } | |
93 | ||
94 | static DnsServer* dns_server_free(DnsServer *s) { | |
95 | if (!s) | |
96 | return NULL; | |
5eef597e | 97 | |
7035cd9e MP |
98 | if (s->link && s->link->current_dns_server == s) |
99 | link_set_dns_server(s->link, NULL); | |
100 | ||
101 | if (s->manager && s->manager->current_dns_server == s) | |
102 | manager_set_dns_server(s->manager, NULL); | |
5eef597e | 103 | |
5eef597e MP |
104 | free(s); |
105 | ||
106 | return NULL; | |
107 | } | |
108 | ||
7035cd9e MP |
109 | DnsServer* dns_server_unref(DnsServer *s) { |
110 | if (!s) | |
111 | return NULL; | |
112 | ||
113 | assert(s->n_ref > 0); | |
114 | ||
115 | if (s->n_ref == 1) | |
116 | dns_server_free(s); | |
117 | else | |
118 | s->n_ref --; | |
119 | ||
120 | return NULL; | |
121 | } | |
122 | ||
13d276d0 MP |
123 | void dns_server_packet_received(DnsServer *s, usec_t rtt) { |
124 | assert(s); | |
125 | ||
126 | if (rtt > s->max_rtt) { | |
127 | s->max_rtt = rtt; | |
128 | s->resend_timeout = MIN(MAX(DNS_TIMEOUT_MIN_USEC, s->max_rtt * 2), | |
129 | DNS_TIMEOUT_MAX_USEC); | |
130 | } | |
131 | } | |
132 | ||
133 | void dns_server_packet_lost(DnsServer *s, usec_t usec) { | |
134 | assert(s); | |
135 | ||
136 | if (s->resend_timeout <= usec) | |
137 | s->resend_timeout = MIN(s->resend_timeout * 2, DNS_TIMEOUT_MAX_USEC); | |
138 | } | |
139 | ||
6300502b | 140 | static void dns_server_hash_func(const void *p, struct siphash *state) { |
5eef597e | 141 | const DnsServer *s = p; |
5eef597e | 142 | |
6300502b | 143 | assert(s); |
5eef597e | 144 | |
6300502b MP |
145 | siphash24_compress(&s->family, sizeof(s->family), state); |
146 | siphash24_compress(&s->address, FAMILY_ADDRESS_SIZE(s->family), state); | |
5eef597e MP |
147 | } |
148 | ||
149 | static int dns_server_compare_func(const void *a, const void *b) { | |
150 | const DnsServer *x = a, *y = b; | |
151 | ||
152 | if (x->family < y->family) | |
153 | return -1; | |
154 | if (x->family > y->family) | |
155 | return 1; | |
156 | ||
157 | return memcmp(&x->address, &y->address, FAMILY_ADDRESS_SIZE(x->family)); | |
158 | } | |
159 | ||
160 | const struct hash_ops dns_server_hash_ops = { | |
161 | .hash = dns_server_hash_func, | |
162 | .compare = dns_server_compare_func | |
163 | }; |