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
58bool endpoint_specified;	/* user gave explicit endpoint discriminator */
59char *bundle_id;		/* identifier for our bundle */
60char *blinks_id;		/* key for the list of links */
61bool doing_multilink;		/* multilink was enabled and agreed to */
62bool multilink_master;		/* we own the multilink bundle */
63
64extern TDB_CONTEXT *pppdb;
65extern char db_key[];
66
67static void make_bundle_links (int append);
68static void remove_bundle_link (void);
69static void iterate_bundle_links (void (*func) (char *));
70
71static int get_default_epdisc (struct epdisc *);
72static int parse_num (char *str, const char *key, int *valp);
73static 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
90void
91mp_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 */
118int
119mp_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_MRU;
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			netif_set_mtu(pcb, mtu);
152			return 0;
153		}
154		make_new_bundle(0, 0, 0, 0);
155		set_ifunit(1);
156		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		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	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
257void mp_exit_bundle()
258{
259	lock_db();
260	remove_bundle_link();
261	unlock_db();
262}
263
264static 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
275void 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
304static 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
344static 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
374static 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
406static int
407parse_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 */
430static int
431owns_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
451static int
452get_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
488static char *endp_class_names[] = {
489    "null", "local", "IP", "MAC", "magic", "phone"
490};
491
492char *
493epdisc_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
534static 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
543int
544str_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