1/*	$OpenBSD: control.c,v 1.28 2023/03/08 04:43:14 guenther 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
19#include <sys/types.h>
20#include <sys/stat.h>
21#include <sys/socket.h>
22#include <sys/un.h>
23#include <errno.h>
24#include <fcntl.h>
25#include <stdlib.h>
26#include <string.h>
27#include <unistd.h>
28
29#include "ripd.h"
30#include "rip.h"
31#include "ripe.h"
32#include "log.h"
33#include "control.h"
34
35TAILQ_HEAD(ctl_conns, ctl_conn)	ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);
36
37#define	CONTROL_BACKLOG	5
38
39struct ctl_conn	*control_connbyfd(int);
40struct ctl_conn	*control_connbypid(pid_t);
41void		 control_close(int);
42
43struct {
44	struct event	ev;
45	struct event	evt;
46	int		fd;
47} control_state;
48
49int
50control_init(char *path)
51{
52	struct sockaddr_un	 sun;
53	int			 fd;
54	mode_t			 old_umask;
55
56	if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
57	    0)) == -1) {
58		log_warn("control_init: socket");
59		return (-1);
60	}
61
62	bzero(&sun, sizeof(sun));
63	sun.sun_family = AF_UNIX;
64	strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
65
66	if (unlink(path) == -1)
67		if (errno != ENOENT) {
68			log_warn("control_init: unlink %s", path);
69			close(fd);
70			return (-1);
71		}
72
73	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
74	if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
75		log_warn("control_init: bind: %s", path);
76		close(fd);
77		umask(old_umask);
78		return (-1);
79	}
80	umask(old_umask);
81
82	if (chmod(path, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) == -1) {
83		log_warn("control_init: chmod");
84		close(fd);
85		(void)unlink(path);
86		return (-1);
87	}
88
89	control_state.fd = fd;
90
91	return (0);
92}
93
94int
95control_listen(void)
96{
97	if (listen(control_state.fd, CONTROL_BACKLOG) == -1) {
98		log_warn("control_listen: listen");
99		return (-1);
100	}
101
102	event_set(&control_state.ev, control_state.fd, EV_READ,
103	    control_accept, NULL);
104	event_add(&control_state.ev, NULL);
105	evtimer_set(&control_state.evt, control_accept, NULL);
106
107	return (0);
108}
109
110void
111control_accept(int listenfd, short event, void *bula)
112{
113	int			 connfd;
114	socklen_t		 len;
115	struct sockaddr_un	 sun;
116	struct ctl_conn		*c;
117
118	event_add(&control_state.ev, NULL);
119	if ((event & EV_TIMEOUT))
120		return;
121
122	len = sizeof(sun);
123	if ((connfd = accept4(listenfd, (struct sockaddr *)&sun, &len,
124	    SOCK_CLOEXEC | SOCK_NONBLOCK)) == -1) {
125		/*
126		 * Pause accept if we are out of file descriptors, or
127		 * libevent will haunt us here too.
128		 */
129		if (errno == ENFILE || errno == EMFILE) {
130			struct timeval evtpause = { 1, 0 };
131
132			event_del(&control_state.ev);
133			evtimer_add(&control_state.evt, &evtpause);
134		} else if (errno != EWOULDBLOCK && errno != EINTR &&
135		    errno != ECONNABORTED)
136			log_warn("control_accept: accept");
137		return;
138	}
139
140	if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
141		log_warn("control_accept");
142		close(connfd);
143		return;
144	}
145
146	imsg_init(&c->iev.ibuf, connfd);
147	c->iev.handler = control_dispatch_imsg;
148	c->iev.events = EV_READ;
149	event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events,
150	    c->iev.handler, &c->iev);
151	event_add(&c->iev.ev, NULL);
152
153	TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
154}
155
156struct ctl_conn *
157control_connbyfd(int fd)
158{
159	struct ctl_conn	*c;
160
161	TAILQ_FOREACH(c, &ctl_conns, entry) {
162		if (c->iev.ibuf.fd == fd)
163			break;
164	}
165
166	return (c);
167}
168
169struct ctl_conn *
170control_connbypid(pid_t pid)
171{
172	struct ctl_conn	*c;
173
174	TAILQ_FOREACH(c, &ctl_conns, entry) {
175		if (c->iev.ibuf.pid == pid)
176			break;
177	}
178
179	return (c);
180}
181
182void
183control_close(int fd)
184{
185	struct ctl_conn	*c;
186
187	if ((c = control_connbyfd(fd)) == NULL) {
188		log_warn("control_close: fd %d: not found", fd);
189		return;
190	}
191
192	msgbuf_clear(&c->iev.ibuf.w);
193	TAILQ_REMOVE(&ctl_conns, c, entry);
194
195	event_del(&c->iev.ev);
196	close(c->iev.ibuf.fd);
197
198	/* Some file descriptors are available again. */
199	if (evtimer_pending(&control_state.evt, NULL)) {
200		evtimer_del(&control_state.evt);
201		event_add(&control_state.ev, NULL);
202	}
203
204	free(c);
205}
206
207void
208control_dispatch_imsg(int fd, short event, void *bula)
209{
210	struct ctl_conn	*c;
211	struct imsg	 imsg;
212	ssize_t		 n;
213	unsigned int	 ifidx;
214	int		 verbose;
215
216	if ((c = control_connbyfd(fd)) == NULL) {
217		log_warn("control_dispatch_imsg: fd %d: not found", fd);
218		return;
219	}
220
221	if (event & EV_READ) {
222		if (((n = imsg_read(&c->iev.ibuf)) == -1 && errno != EAGAIN) ||
223		    n == 0) {
224			control_close(fd);
225			return;
226		}
227	}
228	if (event & EV_WRITE) {
229		if (msgbuf_write(&c->iev.ibuf.w) <= 0 && errno != EAGAIN) {
230			control_close(fd);
231			return;
232		}
233	}
234
235	for (;;) {
236		if ((n = imsg_get(&c->iev.ibuf, &imsg)) == -1) {
237			control_close(fd);
238			return;
239		}
240
241		if (n == 0)
242			break;
243
244		switch (imsg.hdr.type) {
245		case IMSG_CTL_SHOW_INTERFACE:
246			if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(ifidx))
247				return;
248
249			memcpy(&ifidx, imsg.data, sizeof(ifidx));
250			ripe_iface_ctl(c, ifidx);
251			imsg_compose(&c->iev.ibuf, IMSG_CTL_END, 0, 0,
252			    -1, NULL, 0);
253
254			break;
255		case IMSG_CTL_SHOW_RIB:
256			c->iev.ibuf.pid = imsg.hdr.pid;
257			ripe_imsg_compose_rde(imsg.hdr.type, 0,
258			    imsg.hdr.pid, imsg.data, imsg.hdr.len -
259			    IMSG_HEADER_SIZE);
260			break;
261		case IMSG_CTL_SHOW_NBR:
262			ripe_nbr_ctl(c);
263			break;
264		case IMSG_CTL_KROUTE_ADDR:
265		case IMSG_CTL_KROUTE:
266		case IMSG_CTL_IFINFO:
267			c->iev.ibuf.pid = imsg.hdr.pid;
268			ripe_imsg_compose_parent(imsg.hdr.type,
269			    imsg.hdr.pid, imsg.data,
270			    imsg.hdr.len - IMSG_HEADER_SIZE);
271			break;
272		case IMSG_CTL_FIB_COUPLE:
273		case IMSG_CTL_FIB_DECOUPLE:
274		case IMSG_CTL_RELOAD:
275			c->iev.ibuf.pid = imsg.hdr.pid;
276			ripe_imsg_compose_parent(imsg.hdr.type, 0, NULL, 0);
277			break;
278		case IMSG_CTL_LOG_VERBOSE:
279			if (imsg.hdr.len != IMSG_HEADER_SIZE +
280			    sizeof(verbose))
281				break;
282
283			/* forward to other processes */
284			ripe_imsg_compose_parent(imsg.hdr.type, imsg.hdr.pid,
285			    imsg.data, imsg.hdr.len - IMSG_HEADER_SIZE);
286			ripe_imsg_compose_rde(imsg.hdr.type, 0, imsg.hdr.pid,
287			    imsg.data, imsg.hdr.len - IMSG_HEADER_SIZE);
288
289			memcpy(&verbose, imsg.data, sizeof(verbose));
290			log_verbose(verbose);
291			break;
292		default:
293			log_debug("control_dispatch_imsg: "
294			    "error handling imsg %d", imsg.hdr.type);
295			break;
296		}
297		imsg_free(&imsg);
298	}
299
300	imsg_event_add(&c->iev);
301}
302
303int
304control_imsg_relay(struct imsg *imsg)
305{
306	struct ctl_conn	*c;
307
308	if ((c = control_connbypid(imsg->hdr.pid)) == NULL)
309		return (0);
310
311	return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid,
312	    -1, imsg->data, imsg->hdr.len - IMSG_HEADER_SIZE));
313}
314