1 /* $OpenBSD: control.c,v 1.12 2024/11/21 13:35:20 claudio Exp $ */
2
3 /*
4 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18 #include <sys/types.h>
19 #include <sys/queue.h>
20 #include <sys/stat.h>
21 #include <sys/socket.h>
22 #include <sys/uio.h>
23 #include <sys/un.h>
24
25 #include <net/if.h>
26 #include <netinet/in.h>
27 #include <netinet/if_ether.h>
28
29 #include <errno.h>
30 #include <event.h>
31 #include <imsg.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <unistd.h>
35
36 #include "log.h"
37 #include "dhcpleased.h"
38 #include "control.h"
39 #include "frontend.h"
40
41 #define CONTROL_BACKLOG 5
42
43 struct {
44 struct event ev;
45 struct event evt;
46 int fd;
47 } control_state = {.fd = -1};
48
49 struct ctl_conn {
50 TAILQ_ENTRY(ctl_conn) entry;
51 struct imsgev iev;
52 };
53
54 struct ctl_conn *control_connbyfd(int);
55 struct ctl_conn *control_connbypid(pid_t);
56 void control_close(int);
57
58 TAILQ_HEAD(ctl_conns, ctl_conn) ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);
59
60 int
control_init(char * path)61 control_init(char *path)
62 {
63 struct sockaddr_un sun;
64 int fd;
65 mode_t old_umask;
66
67 if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
68 0)) == -1) {
69 log_warn("%s: socket", __func__);
70 return (-1);
71 }
72
73 memset(&sun, 0, sizeof(sun));
74 sun.sun_family = AF_UNIX;
75 strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
76
77 if (unlink(path) == -1)
78 if (errno != ENOENT) {
79 log_warn("%s: unlink %s", __func__, path);
80 close(fd);
81 return (-1);
82 }
83
84 old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
85 if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
86 log_warn("%s: bind: %s", __func__, path);
87 close(fd);
88 umask(old_umask);
89 return (-1);
90 }
91 umask(old_umask);
92
93 if (chmod(path, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) == -1) {
94 log_warn("%s: chmod", __func__);
95 close(fd);
96 (void)unlink(path);
97 return (-1);
98 }
99
100 return (fd);
101 }
102
103 int
control_listen(int fd)104 control_listen(int fd)
105 {
106 if (control_state.fd != -1)
107 fatalx("%s: received unexpected controlsock", __func__);
108
109 control_state.fd = fd;
110 if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
111 log_warn("%s: listen", __func__);
112 return (-1);
113 }
114
115 event_set(&control_state.ev, control_state.fd, EV_READ,
116 control_accept, NULL);
117 event_add(&control_state.ev, NULL);
118 evtimer_set(&control_state.evt, control_accept, NULL);
119
120 return (0);
121 }
122
123 void
control_accept(int listenfd,short event,void * bula)124 control_accept(int listenfd, short event, void *bula)
125 {
126 int connfd;
127 socklen_t len;
128 struct sockaddr_un sun;
129 struct ctl_conn *c;
130
131 event_add(&control_state.ev, NULL);
132 if ((event & EV_TIMEOUT))
133 return;
134
135 len = sizeof(sun);
136 if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len,
137 SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) {
138 /*
139 * Pause accept if we are out of file descriptors, or
140 * libevent will haunt us here too.
141 */
142 if (errno == ENFILE || errno == EMFILE) {
143 struct timeval evtpause = { 1, 0 };
144
145 event_del(&control_state.ev);
146 evtimer_add(&control_state.evt, &evtpause);
147 } else if (errno != EWOULDBLOCK && errno != EINTR &&
148 errno != ECONNABORTED)
149 log_warn("%s: accept4", __func__);
150 return;
151 }
152
153 if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
154 log_warn("%s: calloc", __func__);
155 close(connfd);
156 return;
157 }
158
159 if (imsgbuf_init(&c->iev.ibuf, connfd) == -1) {
160 log_warn("%s: imsgbuf_init", __func__);
161 close(connfd);
162 free(c);
163 return;
164 }
165 c->iev.handler = control_dispatch_imsg;
166 c->iev.events = EV_READ;
167 event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events,
168 c->iev.handler, &c->iev);
169 event_add(&c->iev.ev, NULL);
170
171 TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
172 }
173
174 struct ctl_conn *
control_connbyfd(int fd)175 control_connbyfd(int fd)
176 {
177 struct ctl_conn *c;
178
179 TAILQ_FOREACH(c, &ctl_conns, entry) {
180 if (c->iev.ibuf.fd == fd)
181 break;
182 }
183
184 return (c);
185 }
186
187 struct ctl_conn *
control_connbypid(pid_t pid)188 control_connbypid(pid_t pid)
189 {
190 struct ctl_conn *c;
191
192 TAILQ_FOREACH(c, &ctl_conns, entry) {
193 if (c->iev.ibuf.pid == pid)
194 break;
195 }
196
197 return (c);
198 }
199
200 void
control_close(int fd)201 control_close(int fd)
202 {
203 struct ctl_conn *c;
204
205 if ((c = control_connbyfd(fd)) == NULL) {
206 log_warnx("%s: fd %d: not found", __func__, fd);
207 return;
208 }
209
210 imsgbuf_clear(&c->iev.ibuf);
211 TAILQ_REMOVE(&ctl_conns, c, entry);
212
213 event_del(&c->iev.ev);
214 close(c->iev.ibuf.fd);
215
216 /* Some file descriptors are available again. */
217 if (evtimer_pending(&control_state.evt, NULL)) {
218 evtimer_del(&control_state.evt);
219 event_add(&control_state.ev, NULL);
220 }
221
222 free(c);
223 }
224
225 void
control_dispatch_imsg(int fd,short event,void * bula)226 control_dispatch_imsg(int fd, short event, void *bula)
227 {
228 struct ctl_conn *c;
229 struct imsg imsg;
230 ssize_t n;
231 int verbose;
232 uint32_t if_index, type;
233 pid_t pid;
234
235 if ((c = control_connbyfd(fd)) == NULL) {
236 log_warnx("%s: fd %d: not found", __func__, fd);
237 return;
238 }
239
240 if (event & EV_READ) {
241 if (imsgbuf_read(&c->iev.ibuf) != 1) {
242 control_close(fd);
243 return;
244 }
245 }
246 if (event & EV_WRITE) {
247 if (imsgbuf_write(&c->iev.ibuf) == -1) {
248 control_close(fd);
249 return;
250 }
251 }
252
253 for (;;) {
254 if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
255 control_close(fd);
256 return;
257 }
258 if (n == 0)
259 break;
260
261 type = imsg_get_type(&imsg);
262 pid = imsg_get_pid(&imsg);
263
264 switch (type) {
265 case IMSG_CTL_RELOAD:
266 frontend_imsg_compose_main(type, 0, NULL, 0);
267 break;
268 case IMSG_CTL_LOG_VERBOSE:
269 if (imsg_get_data(&imsg, &verbose,
270 sizeof(verbose)) == -1)
271 break;
272
273 c->iev.ibuf.pid = pid;
274 /* Forward to all other processes. */
275 frontend_imsg_compose_main(type, pid, &verbose,
276 sizeof(verbose));
277 frontend_imsg_compose_engine(type, 0, pid, &verbose,
278 sizeof(verbose));
279
280 log_setverbose(verbose);
281 break;
282 case IMSG_CTL_SHOW_INTERFACE_INFO:
283 if (imsg_get_data(&imsg, &if_index,
284 sizeof(if_index)) == -1)
285 break;
286
287 c->iev.ibuf.pid = pid;
288 frontend_imsg_compose_engine(type, 0, pid, &if_index,
289 sizeof(if_index));
290 break;
291 case IMSG_CTL_SEND_REQUEST:
292 if (imsg_get_data(&imsg, &if_index,
293 sizeof(if_index)) == -1)
294 break;
295
296 c->iev.ibuf.pid = pid;
297 frontend_imsg_compose_engine(IMSG_REQUEST_REBOOT, 0,
298 pid, &if_index, sizeof(if_index));
299 break;
300 default:
301 log_debug("%s: error handling imsg %d", __func__, type);
302 break;
303 }
304 imsg_free(&imsg);
305 }
306
307 imsg_event_add(&c->iev);
308 }
309
310 int
control_imsg_relay(struct imsg * imsg)311 control_imsg_relay(struct imsg *imsg)
312 {
313 struct ctl_conn *c;
314
315 if ((c = control_connbypid(imsg_get_pid(imsg))) == NULL)
316 return (0);
317
318 return (imsg_forward_event(&c->iev, imsg));
319 }
320