1/*
2 * multilink.c - support routines for multilink.
3 *
4 * Copyright (c) 2000 Paul Mackerras.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms are permitted
8 * provided that the above copyright notice and this paragraph are
9 * duplicated in all such forms.  The name of the author may not be
10 * used to endorse or promote products derived from this software
11 * without specific prior written permission.
12 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
13 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
14 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
15 */
16#include <string.h>
17#include <ctype.h>
18#include <stdlib.h>
19#include <netdb.h>
20#include <errno.h>
21#include <signal.h>
22#include <netinet/in.h>
23
24#include "pppd.h"
25#include "fsm.h"
26#include "lcp.h"
27#include "tdb.h"
28
29bool endpoint_specified;	/* user gave explicit endpoint discriminator */
30char *bundle_id;		/* identifier for our bundle */
31
32extern TDB_CONTEXT *pppdb;
33extern char db_key[];
34
35static int get_default_epdisc __P((struct epdisc *));
36static int parse_num __P((char *str, const char *key, int *valp));
37static int owns_unit __P((TDB_DATA pid, int unit));
38
39#define set_ip_epdisc(ep, addr) do {	\
40	ep->length = 4;			\
41	ep->value[0] = addr >> 24;	\
42	ep->value[1] = addr >> 16;	\
43	ep->value[2] = addr >> 8;	\
44	ep->value[3] = addr;		\
45} while (0)
46
47#define LOCAL_IP_ADDR(addr)						  \
48	(((addr) & 0xff000000) == 0x0a000000		/* 10.x.x.x */	  \
49	 || ((addr) & 0xfff00000) == 0xac100000		/* 172.16.x.x */  \
50	 || ((addr) & 0xffff0000) == 0xc0a80000)	/* 192.168.x.x */
51
52#define process_exists(n)	(kill((n), 0) == 0 || errno != ESRCH)
53
54void
55mp_check_options()
56{
57	lcp_options *wo = &lcp_wantoptions[0];
58	lcp_options *ao = &lcp_allowoptions[0];
59
60	if (!multilink)
61		return;
62	/* if we're doing multilink, we have to negotiate MRRU */
63	if (!wo->neg_mrru) {
64		/* mrru not specified, default to mru */
65		wo->mrru = wo->mru;
66		wo->neg_mrru = 1;
67	}
68	ao->mrru = ao->mru;
69	ao->neg_mrru = 1;
70
71	if (!wo->neg_endpoint && !noendpoint) {
72		/* get a default endpoint value */
73		wo->neg_endpoint = get_default_epdisc(&wo->endpoint);
74	}
75}
76
77/*
78 * Make a new bundle or join us to an existing bundle
79 * if we are doing multilink.
80 */
81int
82mp_join_bundle()
83{
84	lcp_options *go = &lcp_gotoptions[0];
85	lcp_options *ho = &lcp_hisoptions[0];
86	lcp_options *ao = &lcp_allowoptions[0];
87	int unit, pppd_pid;
88	int l, mtu;
89	char *p;
90	TDB_DATA key, pid, rec;
91
92	if (!go->neg_mrru || !ho->neg_mrru) {
93		/* not doing multilink */
94		if (go->neg_mrru)
95			notice("oops, multilink negotiated only for receive");
96		mtu = ho->neg_mru? ho->mru: PPP_MRU;
97		if (mtu > ao->mru)
98			mtu = ao->mru;
99		if (demand) {
100			/* already have a bundle */
101			cfg_bundle(0, 0, 0, 0);
102			netif_set_mtu(0, mtu);
103			return 0;
104		}
105		make_new_bundle(0, 0, 0, 0);
106		set_ifunit(1);
107		netif_set_mtu(0, mtu);
108		return 0;
109	}
110
111	/*
112	 * Find the appropriate bundle or join a new one.
113	 * First we make up a name for the bundle.
114	 * The length estimate is worst-case assuming every
115	 * character has to be quoted.
116	 */
117	l = 4 * strlen(peer_authname) + 10;
118	if (ho->neg_endpoint)
119		l += 3 * ho->endpoint.length + 8;
120	if (bundle_name)
121		l += 3 * strlen(bundle_name) + 2;
122	bundle_id = malloc(l);
123	if (bundle_id == 0)
124		novm("bundle identifier");
125
126	p = bundle_id;
127	p += slprintf(p, l-1, "BUNDLE=\"%q\"", peer_authname);
128	if (ho->neg_endpoint || bundle_name)
129		*p++ = '/';
130	if (ho->neg_endpoint)
131		p += slprintf(p, bundle_id+l-p, "%s",
132			      epdisc_to_str(&ho->endpoint));
133	if (bundle_name)
134		p += slprintf(p, bundle_id+l-p, "/%v", bundle_name);
135
136	/*
137	 * For demand mode, we only need to configure the bundle
138	 * and attach the link.
139	 */
140	mtu = MIN(ho->mrru, ao->mru);
141	if (demand) {
142		cfg_bundle(go->mrru, ho->mrru, go->neg_ssnhf, ho->neg_ssnhf);
143		netif_set_mtu(0, mtu);
144		script_setenv("BUNDLE", bundle_id + 7, 1);
145		return 0;
146	}
147
148	/*
149	 * Check if the bundle ID is already in the database.
150	 */
151	unit = -1;
152	tdb_writelock(pppdb);
153	key.dptr = bundle_id;
154	key.dsize = p - bundle_id;
155	pid = tdb_fetch(pppdb, key);
156	if (pid.dptr != NULL) {
157		/* bundle ID exists, see if the pppd record exists */
158		rec = tdb_fetch(pppdb, pid);
159		if (rec.dptr != NULL) {
160			/* it is, parse the interface number */
161			parse_num(rec.dptr, "IFNAME=ppp", &unit);
162			/* check the pid value */
163			if (!parse_num(rec.dptr, "PPPD_PID=", &pppd_pid)
164			    || !process_exists(pppd_pid)
165			    || !owns_unit(pid, unit))
166				unit = -1;
167			free(rec.dptr);
168		}
169		free(pid.dptr);
170	}
171
172	if (unit >= 0) {
173		/* attach to existing unit */
174		if (bundle_attach(unit)) {
175			set_ifunit(0);
176			script_setenv("BUNDLE", bundle_id + 7, 0);
177			tdb_writeunlock(pppdb);
178			info("Link attached to %s", ifname);
179			return 1;
180		}
181		/* attach failed because bundle doesn't exist */
182	}
183
184	/* we have to make a new bundle */
185	make_new_bundle(go->mrru, ho->mrru, go->neg_ssnhf, ho->neg_ssnhf);
186	set_ifunit(1);
187	netif_set_mtu(0, mtu);
188	script_setenv("BUNDLE", bundle_id + 7, 1);
189	tdb_writeunlock(pppdb);
190	info("New bundle %s created", ifname);
191	return 0;
192}
193
194static int
195parse_num(str, key, valp)
196     char *str;
197     const char *key;
198     int *valp;
199{
200	char *p, *endp;
201	int i;
202
203	p = strstr(str, key);
204	if (p != 0) {
205		p += strlen(key);
206		i = strtol(p, &endp, 10);
207		if (endp != p && (*endp == 0 || *endp == ';')) {
208			*valp = i;
209			return 1;
210		}
211	}
212	return 0;
213}
214
215/*
216 * Check whether the pppd identified by `key' still owns ppp unit `unit'.
217 */
218static int
219owns_unit(key, unit)
220     TDB_DATA key;
221     int unit;
222{
223	char ifkey[32];
224	TDB_DATA kd, vd;
225	int ret = 0;
226
227	slprintf(ifkey, sizeof(ifkey), "IFNAME=ppp%d", unit);
228	kd.dptr = ifkey;
229	kd.dsize = strlen(ifkey);
230	vd = tdb_fetch(pppdb, kd);
231	if (vd.dptr != NULL) {
232		ret = vd.dsize == key.dsize
233			&& memcmp(vd.dptr, key.dptr, vd.dsize) == 0;
234		free(vd.dptr);
235	}
236	return ret;
237}
238
239static int
240get_default_epdisc(ep)
241     struct epdisc *ep;
242{
243	char *p;
244	struct hostent *hp;
245	u_int32_t addr;
246
247	/* First try for an ethernet MAC address */
248	p = get_first_ethernet();
249	if (p != 0 && get_if_hwaddr(ep->value, p) >= 0) {
250		ep->class = EPD_MAC;
251		ep->length = 6;
252		return 1;
253	}
254
255	/* see if our hostname corresponds to a reasonable IP address */
256	hp = gethostbyname(hostname);
257	if (hp != NULL) {
258		addr = *(u_int32_t *)hp->h_addr;
259		if (!bad_ip_adrs(addr)) {
260			addr = ntohl(addr);
261			if (!LOCAL_IP_ADDR(addr)) {
262				ep->class = EPD_IP;
263				set_ip_epdisc(ep, addr);
264				return 1;
265			}
266		}
267	}
268
269	return 0;
270}
271
272/*
273 * epdisc_to_str - make a printable string from an endpoint discriminator.
274 */
275
276static char *endp_class_names[] = {
277    "null", "local", "IP", "MAC", "magic", "phone"
278};
279
280char *
281epdisc_to_str(ep)
282     struct epdisc *ep;
283{
284	static char str[MAX_ENDP_LEN*3+8];
285	u_char *p = ep->value;
286	int i, mask = 0;
287	char *q, c, c2;
288
289	if (ep->class == EPD_NULL && ep->length == 0)
290		return "null";
291	if (ep->class == EPD_IP && ep->length == 4) {
292		u_int32_t addr;
293
294		GETLONG(addr, p);
295		slprintf(str, sizeof(str), "IP:%I", htonl(addr));
296		return str;
297	}
298
299	c = ':';
300	c2 = '.';
301	if (ep->class == EPD_MAC && ep->length == 6)
302		c2 = ':';
303	else if (ep->class == EPD_MAGIC && (ep->length % 4) == 0)
304		mask = 3;
305	q = str;
306	if (ep->class <= EPD_PHONENUM)
307		q += slprintf(q, sizeof(str)-1, "%s",
308			      endp_class_names[ep->class]);
309	else
310		q += slprintf(q, sizeof(str)-1, "%d", ep->class);
311	c = ':';
312	for (i = 0; i < ep->length && i < MAX_ENDP_LEN; ++i) {
313		if ((i & mask) == 0) {
314			*q++ = c;
315			c = c2;
316		}
317		q += slprintf(q, str + sizeof(str) - q, "%.2x", ep->value[i]);
318	}
319	return str;
320}
321
322static int hexc_val(int c)
323{
324	if (c >= 'a')
325		return c - 'a' + 10;
326	if (c >= 'A')
327		return c - 'A' + 10;
328	return c - '0';
329}
330
331int
332str_to_epdisc(ep, str)
333     struct epdisc *ep;
334     char *str;
335{
336	int i, l;
337	char *p, *endp;
338
339	for (i = EPD_NULL; i <= EPD_PHONENUM; ++i) {
340		int sl = strlen(endp_class_names[i]);
341		if (strncasecmp(str, endp_class_names[i], sl) == 0) {
342			str += sl;
343			break;
344		}
345	}
346	if (i > EPD_PHONENUM) {
347		/* not a class name, try a decimal class number */
348		i = strtol(str, &endp, 10);
349		if (endp == str)
350			return 0;	/* can't parse class number */
351		str = endp;
352	}
353	ep->class = i;
354	if (*str == 0) {
355		ep->length = 0;
356		return 1;
357	}
358	if (*str != ':' && *str != '.')
359		return 0;
360	++str;
361
362	if (i == EPD_IP) {
363		u_int32_t addr;
364		i = parse_dotted_ip(str, &addr);
365		if (i == 0 || str[i] != 0)
366			return 0;
367		set_ip_epdisc(ep, addr);
368		return 1;
369	}
370	if (i == EPD_MAC && get_if_hwaddr(ep->value, str) >= 0) {
371		ep->length = 6;
372		return 1;
373	}
374
375	p = str;
376	for (l = 0; l < MAX_ENDP_LEN; ++l) {
377		if (*str == 0)
378			break;
379		if (p <= str)
380			for (p = str; isxdigit(*p); ++p)
381				;
382		i = p - str;
383		if (i == 0)
384			return 0;
385		ep->value[l] = hexc_val(*str++);
386		if ((i & 1) == 0)
387			ep->value[l] = (ep->value[l] << 4) + hexc_val(*str++);
388		if (*str == ':' || *str == '.')
389			++str;
390	}
391	if (*str != 0 || (ep->class == EPD_MAC && l != 6))
392		return 0;
393	ep->length = l;
394	return 1;
395}
396
397