1 /*
2  * multilink.c - support routines for multilink.
3  *
4  * Copyright (c) 2000-2002 Paul Mackerras. All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  *
13  * 2. The name(s) of the authors of this software must not be used to
14  *    endorse or promote products derived from this software without
15  *    prior written permission.
16  *
17  * 3. Redistributions of any form whatsoever must retain the following
18  *    acknowledgment:
19  *    "This product includes software developed by Paul Mackerras
20  *     <paulus@samba.org>".
21  *
22  * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
23  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
24  * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
25  * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
26  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
27  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
28  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
29  */
30 
31 #include "netif/ppp/ppp_opts.h"
32 #if PPP_SUPPORT && defined(HAVE_MULTILINK) /* don't build if not configured for use in lwipopts.h */
33 
34 /* Multilink support
35  *
36  * Multilink uses Samba TDB (Trivial Database Library), which
37  * we cannot port, because it needs a filesystem.
38  *
39  * We have to choose between doing a memory-shared TDB-clone,
40  * or dropping multilink support at all.
41  */
42 
43 #include <string.h>
44 #include <ctype.h>
45 #include <stdlib.h>
46 #include <netdb.h>
47 #include <errno.h>
48 #include <signal.h>
49 #include <netinet/in.h>
50 #include <unistd.h>
51 
52 #include "netif/ppp/ppp_impl.h"
53 
54 #include "netif/ppp/fsm.h"
55 #include "netif/ppp/lcp.h"
56 #include "netif/ppp/tdb.h"
57 
58 bool endpoint_specified;	/* user gave explicit endpoint discriminator */
59 char *bundle_id;		/* identifier for our bundle */
60 char *blinks_id;		/* key for the list of links */
61 bool doing_multilink;		/* multilink was enabled and agreed to */
62 bool multilink_master;		/* we own the multilink bundle */
63 
64 extern TDB_CONTEXT *pppdb;
65 extern char db_key[];
66 
67 static void make_bundle_links (int append);
68 static void remove_bundle_link (void);
69 static void iterate_bundle_links (void (*func) (char *));
70 
71 static int get_default_epdisc (struct epdisc *);
72 static int parse_num (char *str, const char *key, int *valp);
73 static int owns_unit (TDB_DATA pid, int unit);
74 
75 #define set_ip_epdisc(ep, addr) do {	\
76 	ep->length = 4;			\
77 	ep->value[0] = addr >> 24;	\
78 	ep->value[1] = addr >> 16;	\
79 	ep->value[2] = addr >> 8;	\
80 	ep->value[3] = addr;		\
81 } while (0)
82 
83 #define LOCAL_IP_ADDR(addr)						  \
84 	(((addr) & 0xff000000) == 0x0a000000		/* 10.x.x.x */	  \
85 	 || ((addr) & 0xfff00000) == 0xac100000		/* 172.16.x.x */  \
86 	 || ((addr) & 0xffff0000) == 0xc0a80000)	/* 192.168.x.x */
87 
88 #define process_exists(n)	(kill((n), 0) == 0 || errno != ESRCH)
89 
90 void
91 mp_check_options()
92 {
93 	lcp_options *wo = &lcp_wantoptions[0];
94 	lcp_options *ao = &lcp_allowoptions[0];
95 
96 	doing_multilink = 0;
97 	if (!multilink)
98 		return;
99 	/* if we're doing multilink, we have to negotiate MRRU */
100 	if (!wo->neg_mrru) {
101 		/* mrru not specified, default to mru */
102 		wo->mrru = wo->mru;
103 		wo->neg_mrru = 1;
104 	}
105 	ao->mrru = ao->mru;
106 	ao->neg_mrru = 1;
107 
108 	if (!wo->neg_endpoint && !noendpoint) {
109 		/* get a default endpoint value */
110 		wo->neg_endpoint = get_default_epdisc(&wo->endpoint);
111 	}
112 }
113 
114 /*
115  * Make a new bundle or join us to an existing bundle
116  * if we are doing multilink.
117  */
118 int
119 mp_join_bundle()
120 {
121 	lcp_options *go = &lcp_gotoptions[0];
122 	lcp_options *ho = &lcp_hisoptions[0];
123 	lcp_options *ao = &lcp_allowoptions[0];
124 	int unit, pppd_pid;
125 	int l, mtu;
126 	char *p;
127 	TDB_DATA key, pid, rec;
128 
129 	if (doing_multilink) {
130 		/* have previously joined a bundle */
131 		if (!go->neg_mrru || !ho->neg_mrru) {
132 			notice("oops, didn't get multilink on renegotiation");
133 			lcp_close(pcb, "multilink required");
134 			return 0;
135 		}
136 		/* XXX should check the peer_authname and ho->endpoint
137 		   are the same as previously */
138 		return 0;
139 	}
140 
141 	if (!go->neg_mrru || !ho->neg_mrru) {
142 		/* not doing multilink */
143 		if (go->neg_mrru)
144 			notice("oops, multilink negotiated only for receive");
145 		mtu = ho->neg_mru? ho->mru: PPP_DEFMRU;
146 		if (mtu > ao->mru)
147 			mtu = ao->mru;
148 		if (demand) {
149 			/* already have a bundle */
150 			cfg_bundle(0, 0, 0, 0);
151 			ppp_netif_set_mtu(pcb, mtu);
152 			return 0;
153 		}
154 		make_new_bundle(0, 0, 0, 0);
155 		set_ifunit(1);
156 		ppp_netif_set_mtu(pcb, mtu);
157 		return 0;
158 	}
159 
160 	doing_multilink = 1;
161 
162 	/*
163 	 * Find the appropriate bundle or join a new one.
164 	 * First we make up a name for the bundle.
165 	 * The length estimate is worst-case assuming every
166 	 * character has to be quoted.
167 	 */
168 	l = 4 * strlen(peer_authname) + 10;
169 	if (ho->neg_endpoint)
170 		l += 3 * ho->endpoint.length + 8;
171 	if (bundle_name)
172 		l += 3 * strlen(bundle_name) + 2;
173 	bundle_id = malloc(l);
174 	if (bundle_id == 0)
175 		novm("bundle identifier");
176 
177 	p = bundle_id;
178 	p += slprintf(p, l-1, "BUNDLE=\"%q\"", peer_authname);
179 	if (ho->neg_endpoint || bundle_name)
180 		*p++ = '/';
181 	if (ho->neg_endpoint)
182 		p += slprintf(p, bundle_id+l-p, "%s",
183 			      epdisc_to_str(&ho->endpoint));
184 	if (bundle_name)
185 		p += slprintf(p, bundle_id+l-p, "/%v", bundle_name);
186 
187 	/* Make the key for the list of links belonging to the bundle */
188 	l = p - bundle_id;
189 	blinks_id = malloc(l + 7);
190 	if (blinks_id == NULL)
191 		novm("bundle links key");
192 	slprintf(blinks_id, l + 7, "BUNDLE_LINKS=%s", bundle_id + 7);
193 
194 	/*
195 	 * For demand mode, we only need to configure the bundle
196 	 * and attach the link.
197 	 */
198 	mtu = LWIP_MIN(ho->mrru, ao->mru);
199 	if (demand) {
200 		cfg_bundle(go->mrru, ho->mrru, go->neg_ssnhf, ho->neg_ssnhf);
201 		ppp_netif_set_mtu(pcb, mtu);
202 		script_setenv("BUNDLE", bundle_id + 7, 1);
203 		return 0;
204 	}
205 
206 	/*
207 	 * Check if the bundle ID is already in the database.
208 	 */
209 	unit = -1;
210 	lock_db();
211 	key.dptr = bundle_id;
212 	key.dsize = p - bundle_id;
213 	pid = tdb_fetch(pppdb, key);
214 	if (pid.dptr != NULL) {
215 		/* bundle ID exists, see if the pppd record exists */
216 		rec = tdb_fetch(pppdb, pid);
217 		if (rec.dptr != NULL && rec.dsize > 0) {
218 			/* make sure the string is null-terminated */
219 			rec.dptr[rec.dsize-1] = 0;
220 			/* parse the interface number */
221 			parse_num(rec.dptr, "IFNAME=ppp", &unit);
222 			/* check the pid value */
223 			if (!parse_num(rec.dptr, "PPPD_PID=", &pppd_pid)
224 			    || !process_exists(pppd_pid)
225 			    || !owns_unit(pid, unit))
226 				unit = -1;
227 			free(rec.dptr);
228 		}
229 		free(pid.dptr);
230 	}
231 
232 	if (unit >= 0) {
233 		/* attach to existing unit */
234 		if (bundle_attach(unit)) {
235 			set_ifunit(0);
236 			script_setenv("BUNDLE", bundle_id + 7, 0);
237 			make_bundle_links(1);
238 			unlock_db();
239 			info("Link attached to %s", ifname);
240 			return 1;
241 		}
242 		/* attach failed because bundle doesn't exist */
243 	}
244 
245 	/* we have to make a new bundle */
246 	make_new_bundle(go->mrru, ho->mrru, go->neg_ssnhf, ho->neg_ssnhf);
247 	set_ifunit(1);
248 	ppp_netif_set_mtu(pcb, mtu);
249 	script_setenv("BUNDLE", bundle_id + 7, 1);
250 	make_bundle_links(pcb);
251 	unlock_db();
252 	info("New bundle %s created", ifname);
253 	multilink_master = 1;
254 	return 0;
255 }
256 
257 void mp_exit_bundle()
258 {
259 	lock_db();
260 	remove_bundle_link();
261 	unlock_db();
262 }
263 
264 static void sendhup(char *str)
265 {
266 	int pid;
267 
268 	if (parse_num(str, "PPPD_PID=", &pid) && pid != getpid()) {
269 		if (debug)
270 			dbglog("sending SIGHUP to process %d", pid);
271 		kill(pid, SIGHUP);
272 	}
273 }
274 
275 void mp_bundle_terminated()
276 {
277 	TDB_DATA key;
278 
279 	bundle_terminating = 1;
280 	upper_layers_down(pcb);
281 	notice("Connection terminated.");
282 #if PPP_STATS_SUPPORT
283 	print_link_stats();
284 #endif /* PPP_STATS_SUPPORT */
285 	if (!demand) {
286 		remove_pidfiles();
287 		script_unsetenv("IFNAME");
288 	}
289 
290 	lock_db();
291 	destroy_bundle();
292 	iterate_bundle_links(sendhup);
293 	key.dptr = blinks_id;
294 	key.dsize = strlen(blinks_id);
295 	tdb_delete(pppdb, key);
296 	unlock_db();
297 
298 	new_phase(PPP_PHASE_DEAD);
299 
300 	doing_multilink = 0;
301 	multilink_master = 0;
302 }
303 
304 static void make_bundle_links(int append)
305 {
306 	TDB_DATA key, rec;
307 	char *p;
308 	char entry[32];
309 	int l;
310 
311 	key.dptr = blinks_id;
312 	key.dsize = strlen(blinks_id);
313 	slprintf(entry, sizeof(entry), "%s;", db_key);
314 	p = entry;
315 	if (append) {
316 		rec = tdb_fetch(pppdb, key);
317 		if (rec.dptr != NULL && rec.dsize > 0) {
318 			rec.dptr[rec.dsize-1] = 0;
319 			if (strstr(rec.dptr, db_key) != NULL) {
320 				/* already in there? strange */
321 				warn("link entry already exists in tdb");
322 				return;
323 			}
324 			l = rec.dsize + strlen(entry);
325 			p = malloc(l);
326 			if (p == NULL)
327 				novm("bundle link list");
328 			slprintf(p, l, "%s%s", rec.dptr, entry);
329 		} else {
330 			warn("bundle link list not found");
331 		}
332 		if (rec.dptr != NULL)
333 			free(rec.dptr);
334 	}
335 	rec.dptr = p;
336 	rec.dsize = strlen(p) + 1;
337 	if (tdb_store(pppdb, key, rec, TDB_REPLACE))
338 		error("couldn't %s bundle link list",
339 		      append? "update": "create");
340 	if (p != entry)
341 		free(p);
342 }
343 
344 static void remove_bundle_link()
345 {
346 	TDB_DATA key, rec;
347 	char entry[32];
348 	char *p, *q;
349 	int l;
350 
351 	key.dptr = blinks_id;
352 	key.dsize = strlen(blinks_id);
353 	slprintf(entry, sizeof(entry), "%s;", db_key);
354 
355 	rec = tdb_fetch(pppdb, key);
356 	if (rec.dptr == NULL || rec.dsize <= 0) {
357 		if (rec.dptr != NULL)
358 			free(rec.dptr);
359 		return;
360 	}
361 	rec.dptr[rec.dsize-1] = 0;
362 	p = strstr(rec.dptr, entry);
363 	if (p != NULL) {
364 		q = p + strlen(entry);
365 		l = strlen(q) + 1;
366 		memmove(p, q, l);
367 		rec.dsize = p - rec.dptr + l;
368 		if (tdb_store(pppdb, key, rec, TDB_REPLACE))
369 			error("couldn't update bundle link list (removal)");
370 	}
371 	free(rec.dptr);
372 }
373 
374 static void iterate_bundle_links(void (*func)(char *))
375 {
376 	TDB_DATA key, rec, pp;
377 	char *p, *q;
378 
379 	key.dptr = blinks_id;
380 	key.dsize = strlen(blinks_id);
381 	rec = tdb_fetch(pppdb, key);
382 	if (rec.dptr == NULL || rec.dsize <= 0) {
383 		error("bundle link list not found (iterating list)");
384 		if (rec.dptr != NULL)
385 			free(rec.dptr);
386 		return;
387 	}
388 	p = rec.dptr;
389 	p[rec.dsize-1] = 0;
390 	while ((q = strchr(p, ';')) != NULL) {
391 		*q = 0;
392 		key.dptr = p;
393 		key.dsize = q - p;
394 		pp = tdb_fetch(pppdb, key);
395 		if (pp.dptr != NULL && pp.dsize > 0) {
396 			pp.dptr[pp.dsize-1] = 0;
397 			func(pp.dptr);
398 		}
399 		if (pp.dptr != NULL)
400 			free(pp.dptr);
401 		p = q + 1;
402 	}
403 	free(rec.dptr);
404 }
405 
406 static int
407 parse_num(str, key, valp)
408      char *str;
409      const char *key;
410      int *valp;
411 {
412 	char *p, *endp;
413 	int i;
414 
415 	p = strstr(str, key);
416 	if (p != 0) {
417 		p += strlen(key);
418 		i = strtol(p, &endp, 10);
419 		if (endp != p && (*endp == 0 || *endp == ';')) {
420 			*valp = i;
421 			return 1;
422 		}
423 	}
424 	return 0;
425 }
426 
427 /*
428  * Check whether the pppd identified by `key' still owns ppp unit `unit'.
429  */
430 static int
431 owns_unit(key, unit)
432      TDB_DATA key;
433      int unit;
434 {
435 	char ifkey[32];
436 	TDB_DATA kd, vd;
437 	int ret = 0;
438 
439 	slprintf(ifkey, sizeof(ifkey), "IFNAME=ppp%d", unit);
440 	kd.dptr = ifkey;
441 	kd.dsize = strlen(ifkey);
442 	vd = tdb_fetch(pppdb, kd);
443 	if (vd.dptr != NULL) {
444 		ret = vd.dsize == key.dsize
445 			&& memcmp(vd.dptr, key.dptr, vd.dsize) == 0;
446 		free(vd.dptr);
447 	}
448 	return ret;
449 }
450 
451 static int
452 get_default_epdisc(ep)
453      struct epdisc *ep;
454 {
455 	char *p;
456 	struct hostent *hp;
457 	u32_t addr;
458 
459 	/* First try for an ethernet MAC address */
460 	p = get_first_ethernet();
461 	if (p != 0 && get_if_hwaddr(ep->value, p) >= 0) {
462 		ep->class = EPD_MAC;
463 		ep->length = 6;
464 		return 1;
465 	}
466 
467 	/* see if our hostname corresponds to a reasonable IP address */
468 	hp = gethostbyname(hostname);
469 	if (hp != NULL) {
470 		addr = *(u32_t *)hp->h_addr;
471 		if (!bad_ip_adrs(addr)) {
472 			addr = lwip_ntohl(addr);
473 			if (!LOCAL_IP_ADDR(addr)) {
474 				ep->class = EPD_IP;
475 				set_ip_epdisc(ep, addr);
476 				return 1;
477 			}
478 		}
479 	}
480 
481 	return 0;
482 }
483 
484 /*
485  * epdisc_to_str - make a printable string from an endpoint discriminator.
486  */
487 
488 static char *endp_class_names[] = {
489     "null", "local", "IP", "MAC", "magic", "phone"
490 };
491 
492 char *
493 epdisc_to_str(ep)
494      struct epdisc *ep;
495 {
496 	static char str[MAX_ENDP_LEN*3+8];
497 	u_char *p = ep->value;
498 	int i, mask = 0;
499 	char *q, c, c2;
500 
501 	if (ep->class == EPD_NULL && ep->length == 0)
502 		return "null";
503 	if (ep->class == EPD_IP && ep->length == 4) {
504 		u32_t addr;
505 
506 		GETLONG(addr, p);
507 		slprintf(str, sizeof(str), "IP:%I", lwip_htonl(addr));
508 		return str;
509 	}
510 
511 	c = ':';
512 	c2 = '.';
513 	if (ep->class == EPD_MAC && ep->length == 6)
514 		c2 = ':';
515 	else if (ep->class == EPD_MAGIC && (ep->length % 4) == 0)
516 		mask = 3;
517 	q = str;
518 	if (ep->class <= EPD_PHONENUM)
519 		q += slprintf(q, sizeof(str)-1, "%s",
520 			      endp_class_names[ep->class]);
521 	else
522 		q += slprintf(q, sizeof(str)-1, "%d", ep->class);
523 	c = ':';
524 	for (i = 0; i < ep->length && i < MAX_ENDP_LEN; ++i) {
525 		if ((i & mask) == 0) {
526 			*q++ = c;
527 			c = c2;
528 		}
529 		q += slprintf(q, str + sizeof(str) - q, "%.2x", ep->value[i]);
530 	}
531 	return str;
532 }
533 
534 static int hexc_val(int c)
535 {
536 	if (c >= 'a')
537 		return c - 'a' + 10;
538 	if (c >= 'A')
539 		return c - 'A' + 10;
540 	return c - '0';
541 }
542 
543 int
544 str_to_epdisc(ep, str)
545      struct epdisc *ep;
546      char *str;
547 {
548 	int i, l;
549 	char *p, *endp;
550 
551 	for (i = EPD_NULL; i <= EPD_PHONENUM; ++i) {
552 		int sl = strlen(endp_class_names[i]);
553 		if (strncasecmp(str, endp_class_names[i], sl) == 0) {
554 			str += sl;
555 			break;
556 		}
557 	}
558 	if (i > EPD_PHONENUM) {
559 		/* not a class name, try a decimal class number */
560 		i = strtol(str, &endp, 10);
561 		if (endp == str)
562 			return 0;	/* can't parse class number */
563 		str = endp;
564 	}
565 	ep->class = i;
566 	if (*str == 0) {
567 		ep->length = 0;
568 		return 1;
569 	}
570 	if (*str != ':' && *str != '.')
571 		return 0;
572 	++str;
573 
574 	if (i == EPD_IP) {
575 		u32_t addr;
576 		i = parse_dotted_ip(str, &addr);
577 		if (i == 0 || str[i] != 0)
578 			return 0;
579 		set_ip_epdisc(ep, addr);
580 		return 1;
581 	}
582 	if (i == EPD_MAC && get_if_hwaddr(ep->value, str) >= 0) {
583 		ep->length = 6;
584 		return 1;
585 	}
586 
587 	p = str;
588 	for (l = 0; l < MAX_ENDP_LEN; ++l) {
589 		if (*str == 0)
590 			break;
591 		if (p <= str)
592 			for (p = str; isxdigit(*p); ++p)
593 				;
594 		i = p - str;
595 		if (i == 0)
596 			return 0;
597 		ep->value[l] = hexc_val(*str++);
598 		if ((i & 1) == 0)
599 			ep->value[l] = (ep->value[l] << 4) + hexc_val(*str++);
600 		if (*str == ':' || *str == '.')
601 			++str;
602 	}
603 	if (*str != 0 || (ep->class == EPD_MAC && l != 6))
604 		return 0;
605 	ep->length = l;
606 	return 1;
607 }
608 
609 #endif /* PPP_SUPPORT && HAVE_MULTILINK */
610