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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 Tom Gundersen <teg@jklm.no> | |
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 <arpa/inet.h> | |
23 | #include <resolv.h> | |
24 | #include <linux/if.h> | |
25 | ||
26 | #include "resolved.h" | |
27 | #include "event-util.h" | |
28 | #include "network-util.h" | |
29 | #include "sd-dhcp-lease.h" | |
30 | #include "dhcp-lease-internal.h" | |
31 | #include "network-internal.h" | |
32 | #include "conf-parser.h" | |
33 | #include "mkdir.h" | |
34 | ||
35 | static int set_fallback_dns(Manager *m, const char *string) { | |
36 | char *word, *state; | |
37 | size_t length; | |
38 | int r; | |
39 | ||
40 | assert(m); | |
41 | assert(string); | |
42 | ||
43 | FOREACH_WORD_QUOTED(word, length, string, state) { | |
44 | _cleanup_free_ Address *address = NULL; | |
45 | Address *tail; | |
46 | _cleanup_free_ char *addrstr = NULL; | |
47 | ||
48 | address = new0(Address, 1); | |
49 | if (!address) | |
50 | return -ENOMEM; | |
51 | ||
52 | addrstr = strndup(word, length); | |
53 | if (!addrstr) | |
54 | return -ENOMEM; | |
55 | ||
56 | r = net_parse_inaddr(addrstr, &address->family, &address->in_addr); | |
57 | if (r < 0) { | |
58 | log_debug("Ignoring invalid DNS address '%s'", addrstr); | |
59 | continue; | |
60 | } | |
61 | ||
62 | LIST_FIND_TAIL(addresses, m->fallback_dns, tail); | |
63 | LIST_INSERT_AFTER(addresses, m->fallback_dns, tail, address); | |
64 | address = NULL; | |
65 | } | |
66 | ||
67 | return 0; | |
68 | } | |
69 | ||
70 | int config_parse_dnsv( | |
71 | const char *unit, | |
72 | const char *filename, | |
73 | unsigned line, | |
74 | const char *section, | |
75 | unsigned section_line, | |
76 | const char *lvalue, | |
77 | int ltype, | |
78 | const char *rvalue, | |
79 | void *data, | |
80 | void *userdata) { | |
81 | ||
82 | Manager *m = userdata; | |
83 | Address *address; | |
84 | ||
85 | assert(filename); | |
86 | assert(lvalue); | |
87 | assert(rvalue); | |
88 | assert(m); | |
89 | ||
90 | while ((address = m->fallback_dns)) { | |
91 | LIST_REMOVE(addresses, m->fallback_dns, address); | |
92 | free(address); | |
93 | } | |
94 | ||
95 | set_fallback_dns(m, rvalue); | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | static int manager_parse_config_file(Manager *m) { | |
101 | static const char fn[] = "/etc/systemd/resolved.conf"; | |
102 | _cleanup_fclose_ FILE *f = NULL; | |
103 | int r; | |
104 | ||
105 | assert(m); | |
106 | ||
107 | f = fopen(fn, "re"); | |
108 | if (!f) { | |
109 | if (errno == ENOENT) | |
110 | return 0; | |
111 | ||
112 | log_warning("Failed to open configuration file %s: %m", fn); | |
113 | return -errno; | |
114 | } | |
115 | ||
116 | r = config_parse(NULL, fn, f, "Resolve\0", config_item_perf_lookup, | |
117 | (void*) resolved_gperf_lookup, false, false, m); | |
118 | if (r < 0) | |
119 | log_warning("Failed to parse configuration file: %s", strerror(-r)); | |
120 | ||
121 | return r; | |
122 | } | |
123 | ||
124 | int manager_new(Manager **ret) { | |
125 | _cleanup_manager_free_ Manager *m = NULL; | |
126 | int r; | |
127 | ||
128 | m = new0(Manager, 1); | |
129 | if (!m) | |
130 | return -ENOMEM; | |
131 | ||
132 | r = set_fallback_dns(m, DNS_SERVERS); | |
133 | if (r < 0) | |
134 | return r; | |
135 | ||
136 | r = manager_parse_config_file(m); | |
137 | if (r < 0) | |
138 | return r; | |
139 | ||
140 | r = sd_event_default(&m->event); | |
141 | if (r < 0) | |
142 | return r; | |
143 | ||
144 | sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL); | |
145 | sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL); | |
146 | ||
147 | sd_event_set_watchdog(m->event, true); | |
148 | ||
149 | *ret = m; | |
150 | m = NULL; | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
155 | void manager_free(Manager *m) { | |
156 | Address *address; | |
157 | ||
158 | if (!m) | |
159 | return; | |
160 | ||
161 | sd_event_unref(m->event); | |
162 | ||
163 | while ((address = m->fallback_dns)) { | |
164 | LIST_REMOVE(addresses, m->fallback_dns, address); | |
165 | free(address); | |
166 | } | |
167 | ||
168 | free(m); | |
169 | } | |
170 | ||
171 | static void append_dns(FILE *f, void *dns, unsigned char family, unsigned *count) { | |
172 | char buf[INET6_ADDRSTRLEN]; | |
173 | const char *address; | |
174 | ||
175 | assert(f); | |
176 | assert(dns); | |
177 | assert(count); | |
178 | ||
179 | address = inet_ntop(family, dns, buf, INET6_ADDRSTRLEN); | |
180 | if (!address) { | |
181 | log_warning("Invalid DNS address. Ignoring."); | |
182 | return; | |
183 | } | |
184 | ||
185 | if (*count == MAXNS) | |
186 | fputs("# Too many DNS servers configured, the following entries " | |
187 | "may be ignored\n", f); | |
188 | ||
189 | fprintf(f, "nameserver %s\n", address); | |
190 | ||
191 | (*count) ++; | |
192 | } | |
193 | ||
194 | int manager_update_resolv_conf(Manager *m) { | |
195 | _cleanup_free_ char *temp_path = NULL; | |
196 | _cleanup_fclose_ FILE *f = NULL; | |
197 | _cleanup_free_ unsigned *indices = NULL; | |
198 | Address *address; | |
199 | unsigned count = 0; | |
200 | int n, r, i; | |
201 | ||
202 | assert(m); | |
203 | ||
204 | r = fopen_temporary("/run/systemd/network/resolv.conf", &f, &temp_path); | |
205 | if (r < 0) | |
206 | return r; | |
207 | ||
208 | fchmod(fileno(f), 0644); | |
209 | ||
210 | fputs("# This file is managed by systemd-resolved(8). Do not edit.\n#\n" | |
211 | "# Third party programs must not access this file directly, but\n" | |
212 | "# only through the symlink at /etc/resolv.conf. To manage\n" | |
213 | "# resolv.conf(5) in a different way, replace the symlink by a\n" | |
214 | "# static file or a different symlink.\n\n", f); | |
215 | ||
216 | n = sd_network_get_ifindices(&indices); | |
217 | if (n < 0) | |
218 | n = 0; | |
219 | ||
220 | for (i = 0; i < n; i++) { | |
221 | _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL; | |
222 | struct in_addr *nameservers; | |
223 | struct in6_addr *nameservers6; | |
224 | size_t nameservers_size; | |
225 | ||
226 | r = sd_network_dhcp_use_dns(indices[i]); | |
227 | if (r > 0) { | |
228 | r = sd_network_get_dhcp_lease(indices[i], &lease); | |
229 | if (r >= 0) { | |
230 | r = sd_dhcp_lease_get_dns(lease, &nameservers, &nameservers_size); | |
231 | if (r >= 0) { | |
232 | unsigned j; | |
233 | ||
234 | for (j = 0; j < nameservers_size; j++) | |
235 | append_dns(f, &nameservers[j], AF_INET, &count); | |
236 | } | |
237 | } | |
238 | } | |
239 | ||
240 | r = sd_network_get_dns(indices[i], &nameservers, &nameservers_size); | |
241 | if (r >= 0) { | |
242 | unsigned j; | |
243 | ||
244 | for (j = 0; j < nameservers_size; j++) | |
245 | append_dns(f, &nameservers[j], AF_INET, &count); | |
246 | ||
247 | free(nameservers); | |
248 | } | |
249 | ||
250 | r = sd_network_get_dns6(indices[i], &nameservers6, &nameservers_size); | |
251 | if (r >= 0) { | |
252 | unsigned j; | |
253 | ||
254 | for (j = 0; j < nameservers_size; j++) | |
255 | append_dns(f, &nameservers6[j], AF_INET6, &count); | |
256 | ||
257 | free(nameservers6); | |
258 | } | |
259 | } | |
260 | ||
261 | LIST_FOREACH(addresses, address, m->fallback_dns) | |
262 | append_dns(f, &address->in_addr, address->family, &count); | |
263 | ||
264 | fflush(f); | |
265 | ||
266 | if (ferror(f) || rename(temp_path, "/run/systemd/network/resolv.conf") < 0) { | |
267 | r = -errno; | |
268 | unlink("/run/systemd/network/resolv.conf"); | |
269 | unlink(temp_path); | |
270 | return r; | |
271 | } | |
272 | ||
273 | return 0; | |
274 | } | |
275 | ||
276 | static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents, | |
277 | void *userdata) { | |
278 | Manager *m = userdata; | |
279 | int r; | |
280 | ||
281 | assert(m); | |
282 | ||
283 | r = manager_update_resolv_conf(m); | |
284 | if (r < 0) | |
285 | log_warning("Could not update resolv.conf: %s", strerror(-r)); | |
286 | ||
287 | sd_network_monitor_flush(m->network_monitor); | |
288 | ||
289 | return 0; | |
290 | } | |
291 | ||
292 | int manager_network_monitor_listen(Manager *m) { | |
293 | _cleanup_event_source_unref_ sd_event_source *event_source = NULL; | |
294 | _cleanup_network_monitor_unref_ sd_network_monitor *monitor = NULL; | |
295 | int r, fd, events; | |
296 | ||
297 | r = sd_network_monitor_new(NULL, &monitor); | |
298 | if (r < 0) | |
299 | return r; | |
300 | ||
301 | fd = sd_network_monitor_get_fd(monitor); | |
302 | if (fd < 0) | |
303 | return fd; | |
304 | ||
305 | events = sd_network_monitor_get_events(monitor); | |
306 | if (events < 0) | |
307 | return events; | |
308 | ||
309 | r = sd_event_add_io(m->event, &event_source, fd, events, | |
310 | &manager_network_event_handler, m); | |
311 | if (r < 0) | |
312 | return r; | |
313 | ||
314 | m->network_monitor = monitor; | |
315 | m->network_event_source = event_source; | |
316 | monitor = NULL; | |
317 | event_source = NULL; | |
318 | ||
319 | return 0; | |
320 | } |