1 /*-
2  * Copyright (c) 2006-2009 Sam Leffler, Errno Consulting
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer,
10  *    without modification.
11  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
12  *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
13  *    redistribution must be conditioned upon including a substantially
14  *    similar Disclaimer requirement for further binary redistribution.
15  *
16  * NO WARRANTY
17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19  * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
21  * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
22  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
25  * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
27  * THE POSSIBILITY OF SUCH DAMAGES.
28  *
29  * $FreeBSD: src/tools/tools/net80211/wlanwds/wlanwds.c,v 1.3 2009/04/18 16:14:03 sam Exp $
30  */
31 
32 /*
33  * Test app to demonstrate how to handle dynamic WDS links:
34  * o monitor 802.11 events for wds discovery events
35  * o create wds vap's in response to wds discovery events
36  *   and launch a script to handle adding the vap to the
37  *   bridge, etc.
38  * o destroy wds vap's when station leaves
39  */
40 #include <sys/param.h>
41 #include <sys/file.h>
42 #include <sys/socket.h>
43 #include <sys/ioctl.h>
44 #include <sys/sysctl.h>
45 #include <sys/types.h>
46 
47 #include <net/if.h>
48 #include "net/if_media.h"
49 #include <net/route.h>
50 #include <net/if_dl.h>
51 #include <netinet/in.h>
52 #include <netinet/if_ether.h>
53 #include <netatalk/at.h>
54 #include "netproto/802_11/ieee80211_ioctl.h"
55 #include "netproto/802_11/ieee80211_dragonfly.h"
56 #include <arpa/inet.h>
57 #include <netdb.h>
58 
59 #include <ctype.h>
60 #include <err.h>
61 #include <errno.h>
62 #include <paths.h>
63 #include <stdarg.h>
64 #include <stdio.h>
65 #include <stdlib.h>
66 #include <string.h>
67 #include <sysexits.h>
68 #include <syslog.h>
69 #include <unistd.h>
70 #include <ifaddrs.h>
71 
72 #define	IEEE80211_ADDR_EQ(a1,a2)	(memcmp(a1,a2,IEEE80211_ADDR_LEN) == 0)
73 #define	IEEE80211_ADDR_COPY(dst,src)	memcpy(dst,src,IEEE80211_ADDR_LEN)
74 
75 struct wds {
76 	struct wds *next;
77 	uint8_t	bssid[IEEE80211_ADDR_LEN];	/* bssid of associated sta */
78 	char	ifname[IFNAMSIZ];		/* vap interface name */
79 };
80 static struct wds *wds;
81 
82 static	const char *script = NULL;
83 static	char **ifnets;
84 static	int nifnets = 0;
85 static	int verbose = 0;
86 static	int discover_on_join = 0;
87 
88 static	void scanforvaps(int s);
89 static	void handle_rtmsg(struct rt_msghdr *rtm, ssize_t msglen);
90 static	void wds_discovery(const char *ifname,
91 		const uint8_t bssid[IEEE80211_ADDR_LEN]);
92 static	void wds_destroy(const char *ifname);
93 static	void wds_leave(const uint8_t bssid[IEEE80211_ADDR_LEN]);
94 static	int wds_vap_create(const char *ifname, struct wds *);
95 static	int wds_vap_destroy(const char *ifname);
96 
97 static void
98 usage(const char *progname)
99 {
100 	fprintf(stderr, "usage: %s [-fjtv] [-P pidfile] [-s <set_scriptname>] [ifnet0 ... | any]\n",
101 		progname);
102 	exit(-1);
103 }
104 
105 int
106 main(int argc, char *argv[])
107 {
108 	const char *progname = argv[0];
109 	const char *pidfile = NULL;
110 	int s, c, logmask, bg = 1;
111 	char msg[2048];
112 
113 	logmask = LOG_UPTO(LOG_INFO);
114 	while ((c = getopt(argc, argv, "fjP:s:tv")) != -1)
115 		switch (c) {
116 		case 'f':
117 			bg = 0;
118 			break;
119 		case 'j':
120 			discover_on_join = 1;
121 			break;
122 		case 'P':
123 			pidfile = optarg;
124 			break;
125 		case 's':
126 			script = optarg;
127 			break;
128 		case 't':
129 			logmask = LOG_UPTO(LOG_ERR);
130 			break;
131 		case 'v':
132 			logmask = LOG_UPTO(LOG_DEBUG);
133 			break;
134 		case '?':
135 			usage(progname);
136 			/*NOTREACHED*/
137 		}
138 	argc -= optind, argv += optind;
139 	if (argc == 0) {
140 		fprintf(stderr, "%s: no ifnet's specified to monitor\n",
141 		    progname);
142 		usage(progname);
143 	}
144 	ifnets = argv;
145 	nifnets = argc;
146 
147 	s = socket(PF_ROUTE, SOCK_RAW, 0);
148 	if (s < 0)
149 		err(EX_OSERR, "socket");
150 	/*
151 	 * Scan for inherited state.
152 	 */
153 	scanforvaps(s);
154 
155 	/* XXX what directory to work in? */
156 	if (bg && daemon(0, 0) < 0)
157 		err(EX_OSERR, "daemon");
158 
159 	openlog("wlanwds", LOG_PID | LOG_CONS, LOG_DAEMON);
160 	setlogmask(logmask);
161 
162 	for (;;) {
163 		ssize_t n = read(s, msg, sizeof(msg));
164 		handle_rtmsg((struct rt_msghdr *)msg, n);
165 	}
166 	return 0;
167 }
168 
169 static const char *
170 ether_sprintf(const uint8_t mac[IEEE80211_ADDR_LEN])
171 {
172 	static char buf[32];
173 
174 	snprintf(buf, sizeof(buf), "%02x:%02x:%02x:%02x:%02x:%02x",
175 		mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
176 	return buf;
177 }
178 
179 /*
180  * Fetch a vap's parent ifnet name.
181  */
182 static int
183 getparent(const char *ifname, char parent[IFNAMSIZ+1])
184 {
185 	char oid[256];
186 	int parentlen;
187 
188 	/* fetch parent interface name */
189 	snprintf(oid, sizeof(oid), "net.wlan.%s.%%parent", ifname+4);
190 	parentlen = IFNAMSIZ;
191 	if (sysctlbyname(oid, parent, &parentlen, NULL, 0) < 0)
192 		return -1;
193 	parent[parentlen] = '\0';
194 	return 0;
195 }
196 
197 /*
198  * Check if the specified ifnet is one we're supposed to monitor.
199  * The ifnet is assumed to be a vap; we find it's parent and check
200  * it against the set of ifnet's specified on the command line.
201  */
202 static int
203 checkifnet(const char *ifname, int complain)
204 {
205 	char parent[256];
206 	int i;
207 
208 	if (getparent(ifname, parent) < 0) {
209 		if (complain)
210 			syslog(LOG_ERR,
211 			   "%s: no pointer to parent interface: %m", ifname);
212 		return 0;
213 	}
214 
215 	for (i = 0; i < nifnets; i++)
216 		if (strcasecmp(ifnets[i], "any") == 0 ||
217 		    strcmp(ifnets[i], parent) == 0)
218 			return 1;
219 	syslog(LOG_DEBUG, "%s: parent %s not being monitored", ifname, parent);
220 	return 0;
221 }
222 
223 /*
224  * Return 1 if the specified ifnet is a WDS vap.
225  */
226 static int
227 iswdsvap(int s, const char *ifname)
228 {
229 	struct ifmediareq ifmr;
230 
231 	memset(&ifmr, 0, sizeof(ifmr));
232 	strncpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
233 	if (ioctl(s, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0)
234 		err(-1, "%s: cannot get media", ifname);
235 	return (ifmr.ifm_current & IFM_IEEE80211_WDS) != 0;
236 }
237 
238 /*
239  * Fetch the bssid for an ifnet.  The caller is assumed
240  * to have already verified this is possible.
241  */
242 static void
243 getbssid(int s, const char *ifname, char bssid[IEEE80211_ADDR_LEN])
244 {
245 	struct ieee80211req ireq;
246 
247 	memset(&ireq, 0, sizeof(ireq));
248 	strncpy(ireq.i_name, ifname, sizeof(ireq.i_name));
249 	ireq.i_type = IEEE80211_IOC_BSSID;
250 	ireq.i_data = bssid;
251 	ireq.i_len = IEEE80211_ADDR_LEN;
252 	if (ioctl(s, SIOCG80211, &ireq) < 0)
253 		err(-1, "%s: cannot fetch bssid", ifname);
254 }
255 
256 /*
257  * Scan the system for WDS vaps associated with the ifnet's we're
258  * supposed to monitor.  Any vaps are added to our internal table
259  * so we can find them (and destroy them) on station leave.
260  */
261 static void
262 scanforvaps(int s)
263 {
264 	char ifname[IFNAMSIZ+1];
265 	char bssid[IEEE80211_ADDR_LEN];
266 	int i;
267 
268 	/* XXX brutal; should just walk sysctl tree */
269 	for (i = 0; i < 128; i++) {
270 		snprintf(ifname, sizeof(ifname), "wlan%d", i);
271 		if (checkifnet(ifname, 0) && iswdsvap(s, ifname)) {
272 			struct wds *p = malloc(sizeof(struct wds));
273 			if (p == NULL)
274 				err(-1, "%s: malloc failed", __func__);
275 			strlcpy(p->ifname, ifname, IFNAMSIZ);
276 			getbssid(s, ifname, p->bssid);
277 			p->next = wds;
278 			wds = p;
279 
280 			syslog(LOG_INFO, "[%s] discover wds vap %s",
281 			    ether_sprintf(bssid), ifname);
282 		}
283 	}
284 }
285 
286 /*
287  * Process a routing socket message.  We handle messages related
288  * to dynamic WDS:
289  * o on WDS discovery (rx of a 4-address frame with DWDS enabled)
290  *   we create a WDS vap for the specified mac address
291  * o on station leave we destroy any associated WDS vap
292  * o on ifnet destroy we update state if this is manual destroy of
293  *   a WDS vap in our table
294  * o if the -j option is supplied on the command line we create
295  *   WDS vaps on station join/rejoin, this is useful for some setups
296  *   where a WDS vap is required for 4-address traffic to flow
297  */
298 static void
299 handle_rtmsg(struct rt_msghdr *rtm, ssize_t msglen)
300 {
301 	struct if_announcemsghdr *ifan;
302 
303 	if (rtm->rtm_version != RTM_VERSION) {
304 		syslog(LOG_ERR, "routing message version %d not understood",
305 		    rtm->rtm_version);
306 		return;
307 	}
308 	switch (rtm->rtm_type) {
309 	case RTM_IFANNOUNCE:
310 		ifan = (struct if_announcemsghdr *)rtm;
311 		switch (ifan->ifan_what) {
312 		case IFAN_ARRIVAL:
313 			syslog(LOG_DEBUG,
314 			    "RTM_IFANNOUNCE: if# %d, what: arrival",
315 			    ifan->ifan_index);
316 			break;
317 		case IFAN_DEPARTURE:
318 			syslog(LOG_DEBUG,
319 			    "RTM_IFANNOUNCE: if# %d, what: departure",
320 			    ifan->ifan_index);
321 			/* NB: ok to call w/ unmonitored ifnets */
322 			wds_destroy(ifan->ifan_name);
323 			break;
324 		}
325 		break;
326 	case RTM_IEEE80211:
327 #define	V(type)	((struct type *)(&ifan[1]))
328 		ifan = (struct if_announcemsghdr *)rtm;
329 		switch (ifan->ifan_what) {
330 		case RTM_IEEE80211_DISASSOC:
331 			if (!discover_on_join)
332 				break;
333 			/* fall thru... */
334 		case RTM_IEEE80211_LEAVE:
335 			if (!checkifnet(ifan->ifan_name, 1))
336 				break;
337 			syslog(LOG_INFO, "[%s] station leave",
338 			    ether_sprintf(V(ieee80211_leave_event)->iev_addr));
339 			wds_leave(V(ieee80211_leave_event)->iev_addr);
340 			break;
341 		case RTM_IEEE80211_JOIN:
342 		case RTM_IEEE80211_REJOIN:
343 		case RTM_IEEE80211_ASSOC:
344 		case RTM_IEEE80211_REASSOC:
345 			if (!discover_on_join)
346 				break;
347 			/* fall thru... */
348 		case RTM_IEEE80211_WDS:
349 			syslog(LOG_INFO, "[%s] wds discovery",
350 			    ether_sprintf(V(ieee80211_wds_event)->iev_addr));
351 			if (!checkifnet(ifan->ifan_name, 1))
352 				break;
353 			wds_discovery(ifan->ifan_name,
354 			    V(ieee80211_wds_event)->iev_addr);
355 			break;
356 		}
357 		break;
358 #undef V
359 	}
360 }
361 
362 /*
363  * Handle WDS discovery; create a WDS vap for the specified bssid.
364  * If a vap already exists then do nothing (can happen when a flood
365  * of 4-address frames causes multiple events to be queued before
366  * we create a vap).
367  */
368 static void
369 wds_discovery(const char *ifname, const uint8_t bssid[IEEE80211_ADDR_LEN])
370 {
371 	struct wds *p;
372 	char parent[256];
373 	char cmd[1024];
374 	int status;
375 
376 	for (p = wds; p != NULL; p = p->next)
377 		if (IEEE80211_ADDR_EQ(p->bssid, bssid)) {
378 			syslog(LOG_INFO, "[%s] wds vap already created (%s)",
379 			    ether_sprintf(bssid), ifname);
380 			return;
381 		}
382 	if (getparent(ifname, parent) < 0) {
383 		syslog(LOG_ERR, "%s: no pointer to parent interface: %m",
384 		    ifname);
385 		return;
386 	}
387 
388 	p = malloc(sizeof(struct wds));
389 	if (p == NULL) {
390 		syslog(LOG_ERR, "%s: malloc failed: %m", __func__);
391 		return;
392 	}
393 	IEEE80211_ADDR_COPY(p->bssid, bssid);
394 	if (wds_vap_create(parent, p) < 0) {
395 		free(p);
396 		return;
397 	}
398 	/*
399 	 * Add to table and launch setup script.
400 	 */
401 	p->next = wds;
402 	wds = p;
403 	syslog(LOG_INFO, "[%s] create wds vap %s", ether_sprintf(bssid),
404 	    p->ifname);
405 	if (script != NULL) {
406 		snprintf(cmd, sizeof(cmd), "%s %s", script, p->ifname);
407 		status = system(cmd);
408 		if (status)
409 			syslog(LOG_ERR, "vap setup script %s exited with "
410 			    "status %d", script, status);
411 	}
412 }
413 
414 /*
415  * Destroy a WDS vap (if known).
416  */
417 static void
418 wds_destroy(const char *ifname)
419 {
420 	struct wds *p, **pp;
421 
422 	for (pp = &wds; (p = *pp) != NULL; pp = &p->next)
423 		if (strncmp(p->ifname, ifname, IFNAMSIZ) == 0)
424 			break;
425 	if (p != NULL) {
426 		*pp = p->next;
427 		/* NB: vap already destroyed */
428 		free(p);
429 		return;
430 	}
431 }
432 
433 /*
434  * Handle a station leave event; destroy any associated WDS vap.
435  */
436 static void
437 wds_leave(const uint8_t bssid[IEEE80211_ADDR_LEN])
438 {
439 	struct wds *p, **pp;
440 
441 	for (pp = &wds; (p = *pp) != NULL; pp = &p->next)
442 		if (IEEE80211_ADDR_EQ(p->bssid, bssid))
443 			break;
444 	if (p != NULL) {
445 		*pp = p->next;
446 		if (wds_vap_destroy(p->ifname) >= 0)
447 			syslog(LOG_INFO, "[%s] wds vap %s destroyed",
448 			    ether_sprintf(bssid), p->ifname);
449 		free(p);
450 	}
451 }
452 
453 static int
454 wds_vap_create(const char *parent, struct wds *p)
455 {
456 	struct ieee80211_clone_params cp;
457 	struct ifreq ifr;
458 	int s, status;
459 
460 	memset(&cp, 0, sizeof(cp));
461 	strncpy(cp.icp_parent, parent, IFNAMSIZ);
462 	cp.icp_opmode = IEEE80211_M_WDS;
463 	IEEE80211_ADDR_COPY(cp.icp_bssid, p->bssid);
464 
465 	memset(&ifr, 0, sizeof(ifr));
466 	strncpy(ifr.ifr_name, "wlan", IFNAMSIZ);
467 	ifr.ifr_data = (void *) &cp;
468 
469 	status = -1;
470 	s = socket(AF_INET, SOCK_DGRAM, 0);
471 	if (s >= 0) {
472 		if (ioctl(s, SIOCIFCREATE2, &ifr) >= 0) {
473 			strlcpy(p->ifname, ifr.ifr_name, IFNAMSIZ);
474 			status = 0;
475 		} else {
476 			syslog(LOG_ERR, "SIOCIFCREATE2("
477 			    "mode %u flags 0x%x parent %s bssid %s): %m",
478 			    cp.icp_opmode, cp.icp_flags, parent,
479 			    ether_sprintf(cp.icp_bssid));
480 		}
481 		close(s);
482 	} else
483 		syslog(LOG_ERR, "socket(SOCK_DRAGM): %m");
484 	return status;
485 }
486 
487 static int
488 wds_vap_destroy(const char *ifname)
489 {
490 	struct ieee80211req ifr;
491 	int s, status;
492 
493 	s = socket(AF_INET, SOCK_DGRAM, 0);
494 	if (s < 0) {
495 		syslog(LOG_ERR, "socket(SOCK_DRAGM): %m");
496 		return -1;
497 	}
498 	memset(&ifr, 0, sizeof(ifr));
499 	strncpy(ifr.i_name, ifname, IFNAMSIZ);
500 	if (ioctl(s, SIOCIFDESTROY, &ifr) < 0) {
501 		syslog(LOG_ERR, "ioctl(SIOCIFDESTROY): %m");
502 		status = -1;
503 	} else
504 		status = 0;
505 	close(s);
506 	return status;
507 }
508