1 /*
2  * multilink.c - support routines for multilink.
3  *
4  * Copyright (c) 2000-2001 by Sun Microsystems, Inc.
5  * All rights reserved.
6  *
7  * Copyright (c) 2000 Paul Mackerras.
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms are permitted
11  * provided that the above copyright notice and this paragraph are
12  * duplicated in all such forms.  The name of the author may not be
13  * used to endorse or promote products derived from this software
14  * without specific prior written permission.
15  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
17  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
18  */
19 
20 #include <string.h>
21 #include <ctype.h>
22 #include <stdlib.h>
23 #include <netdb.h>
24 #include <errno.h>
25 #include <signal.h>
26 #include <netinet/in.h>
27 
28 #include "pppd.h"
29 #include "fsm.h"
30 #include "lcp.h"
31 
32 #ifdef HAVE_MULTILINK
33 #include "tdb.h"
34 #endif
35 
36 #define set_ip_epdisc(ep, addr) (	\
37 	ep->length = 4,			\
38 	ep->value[0] = addr >> 24,	\
39 	ep->value[1] = addr >> 16,	\
40 	ep->value[2] = addr >> 8,	\
41 	ep->value[3] = addr		\
42 )
43 
44 #ifdef HAVE_MULTILINK
45 bool endpoint_specified;	/* user gave explicit endpoint discriminator */
46 char *bundle_id;		/* identifier for our bundle */
47 
48 static int get_default_epdisc __P((struct epdisc *));
49 static int parse_num __P((char *str, const char *key, int *valp));
50 static int owns_unit __P((TDB_DATA pid, int unit));
51 
52 #define process_exists(n)	(kill(0, (n)) == 0 || errno != ESRCH)
53 
54 void
mp_check_options()55 mp_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 		if (wo->neg_endpoint)
75 			dbglog("using default endpoint %s",
76 			       epdisc_to_str(&wo->endpoint));
77 	}
78 }
79 
80 /*
81  * Make a new bundle or join us to an existing bundle
82  * if we are doing multilink.
83  */
84 int
mp_join_bundle()85 mp_join_bundle()
86 {
87 	lcp_options *go = &lcp_gotoptions[0];
88 	lcp_options *ho = &lcp_hisoptions[0];
89 	int unit, pppd_pid;
90 	int l;
91 	char *p;
92 	TDB_DATA key, pid, rec;
93 
94 	if (!go->neg_mrru || !ho->neg_mrru) {
95 		/* not doing multilink */
96 		if (go->neg_mrru)
97 			notice("oops, multilink negotiated only for receive");
98 		multilink = 0;
99 		if (demand) {
100 			/* already have a bundle */
101 			cfg_bundle(0, 0, 0, 0);
102 			return 0;
103 		}
104 		make_new_bundle(0, 0, 0, 0);
105 		set_ifunit(1);
106 		return 0;
107 	}
108 
109 	/*
110 	 * Find the appropriate bundle or join a new one.
111 	 * First we make up a name for the bundle.
112 	 * The length estimate is worst-case assuming every
113 	 * character has to be quoted.
114 	 *
115 	 * Note - RFC 1990 requires that an unnegotiated endpoint
116 	 * discriminator value be equivalent to negotiating with class
117 	 * zero.  Do not test ho->neg_endpoint here.
118 	 */
119 	l = 4 * strlen(peer_authname) + 10;
120 	l += 3 * ho->endpoint.length + 8;
121 	if (bundle_name)
122 		l += 3 * strlen(bundle_name) + 2;
123 	bundle_id = malloc(l);
124 	if (bundle_id == NULL)
125 		novm("bundle identifier");
126 
127 	p = bundle_id;
128 	p += slprintf(p, l-1, "BUNDLE=\"%q\"", peer_authname);
129 	*p++ = '/';
130 	p += slprintf(p, bundle_id+l-p, "%s", epdisc_to_str(&ho->endpoint));
131 	if (bundle_name)
132 		p += slprintf(p, bundle_id+l-p, "/%v", bundle_name);
133 	dbglog("bundle_id = %s", bundle_id+7);
134 
135 	/*
136 	 * For demand mode, we only need to configure the bundle
137 	 * and attach the link.
138 	 */
139 	if (demand) {
140 		cfg_bundle(go->mrru, ho->mrru, go->neg_ssnhf, ho->neg_ssnhf);
141 		script_setenv("BUNDLE", bundle_id + 7, 1);
142 		return 0;
143 	}
144 
145 	/*
146 	 * Check if the bundle ID is already in the database.
147 	 */
148 	unit = -1;
149 	tdb_writelock(pppdb);
150 	key.dptr = bundle_id;
151 	key.dsize = p - bundle_id;
152 	pid = tdb_fetch(pppdb, key);
153 	if (pid.dptr != NULL) {
154 		/* bundle ID exists, see if the pppd record exists */
155 		rec = tdb_fetch(pppdb, pid);
156 		if (rec.dptr != NULL) {
157 			/* it does, parse the interface number */
158 			parse_num(rec.dptr, "IFNAME=ppp", &unit);
159 			/* check the pid value */
160 			if (!parse_num(rec.dptr, "PPPD_PID=", &pppd_pid)
161 			    || !process_exists(pppd_pid)
162 			    || !owns_unit(pid, unit))
163 				unit = -1;
164 			free(rec.dptr);
165 		}
166 		free(pid.dptr);
167 	}
168 
169 	if (unit >= 0) {
170 		/* attach to existing unit */
171 		if (bundle_attach(unit)) {
172 			set_ifunit(0);
173 			script_setenv("BUNDLE", bundle_id + 7, 0);
174 			tdb_writeunlock(pppdb);
175 			info("Link attached to %s", ifname);
176 			return 1;
177 		}
178 		/* attach failed because bundle doesn't exist */
179 	}
180 
181 	/* we have to make a new bundle */
182 	make_new_bundle(go->mrru, ho->mrru, go->neg_ssnhf, ho->neg_ssnhf);
183 	set_ifunit(1);
184 	script_setenv("BUNDLE", bundle_id + 7, 1);
185 	tdb_writeunlock(pppdb);
186 	info("New bundle %s created", ifname);
187 	return 0;
188 }
189 
190 static int
parse_num(str,key,valp)191 parse_num(str, key, valp)
192      char *str;
193      const char *key;
194      int *valp;
195 {
196 	char *p, *endp;
197 	int i;
198 
199 	p = strstr(str, key);
200 	if (p != 0) {
201 		p += strlen(key);
202 		i = strtol(p, &endp, 10);
203 		if (endp != p && (*endp == 0 || *endp == ';')) {
204 			*valp = i;
205 			return 1;
206 		}
207 	}
208 	return 0;
209 }
210 
211 /*
212  * Check whether the pppd identified by `key' still owns ppp unit `unit'.
213  */
214 static int
owns_unit(key,unit)215 owns_unit(key, unit)
216      TDB_DATA key;
217      int unit;
218 {
219 	char ifkey[32];
220 	TDB_DATA kd, vd;
221 	int ret = 0;
222 
223 	(void) slprintf(ifkey, sizeof(ifkey), "IFNAME=ppp%d", unit);
224 	kd.dptr = ifkey;
225 	kd.dsize = strlen(ifkey);
226 	vd = tdb_fetch(pppdb, kd);
227 	if (vd.dptr != NULL) {
228 		ret = vd.dsize == key.dsize
229 			&& memcmp(vd.dptr, key.dptr, vd.dsize) == 0;
230 		free(vd.dptr);
231 	}
232 	return ret;
233 }
234 
235 static int
get_default_epdisc(ep)236 get_default_epdisc(ep)
237      struct epdisc *ep;
238 {
239 	struct hostent *hp;
240 	u_int32_t addr;
241 
242 	if (get_first_hwaddr(ep->value, sizeof(ep->value))) {
243 		ep->class = EPD_MAC;
244 		ep->length = 6;
245 		return 1;
246 	}
247 
248 	/* see if our hostname corresponds to a reasonable IP address */
249 	hp = gethostbyname(hostname);
250 	if (hp != NULL) {
251 		addr = *(u_int32_t *)hp->h_addr;
252 		if (!bad_ip_adrs(addr)) {
253 			addr = ntohl(addr);
254 			if (!LOCAL_IP_ADDR(addr)) {
255 				ep->class = EPD_IP;
256 				set_ip_epdisc(ep, addr);
257 				return 1;
258 			}
259 		}
260 	}
261 
262 	return 0;
263 }
264 #endif /* HAVE_MULTILINK */
265 
266 /*
267  * epdisc_to_str - make a printable string from an endpoint discriminator.
268  */
269 
270 static char *endp_class_names[] = {
271     "null", "local", "IP", "MAC", "magic", "phone"
272 };
273 
274 char *
epdisc_to_str(ep)275 epdisc_to_str(ep)
276      struct epdisc *ep;
277 {
278 	static char str[MAX_ENDP_LEN*3+8];
279 	u_char *p = ep->value;
280 	int i, mask = 0;
281 	char *q, c, c2;
282 
283 	if (ep->class == EPD_NULL && ep->length == 0)
284 		return "null";
285 	if (ep->class == EPD_IP && ep->length == 4) {
286 		u_int32_t addr;
287 
288 		GETLONG(addr, p);
289 		(void) slprintf(str, sizeof(str), "IP:%I", htonl(addr));
290 		return str;
291 	}
292 
293 	c = ':';
294 	c2 = '.';
295 	if (ep->class == EPD_MAC && ep->length == 6)
296 		c2 = ':';
297 	else if (ep->class == EPD_MAGIC && (ep->length % 4) == 0)
298 		mask = 3;
299 	q = str;
300 	if (ep->class <= EPD_PHONENUM)
301 		q += slprintf(q, sizeof(str)-1, "%s",
302 			      endp_class_names[ep->class]);
303 	else
304 		q += slprintf(q, sizeof(str)-1, "%d", ep->class);
305 	c = ':';
306 	for (i = 0; i < ep->length && i < MAX_ENDP_LEN; ++i) {
307 		if ((i & mask) == 0) {
308 			*q++ = c;
309 			c = c2;
310 		}
311 		q += slprintf(q, str + sizeof(str) - q, "%.2x", ep->value[i]);
312 	}
313 	return str;
314 }
315 
hexc_val(int c)316 static int hexc_val(int c)
317 {
318 	if (c >= 'a')
319 		return c - 'a' + 10;
320 	if (c >= 'A')
321 		return c - 'A' + 10;
322 	return c - '0';
323 }
324 
325 int
str_to_epdisc(ep,str)326 str_to_epdisc(ep, str)
327      struct epdisc *ep;
328      char *str;
329 {
330 	int i, l;
331 	char *p, *endp;
332 
333 	for (i = EPD_NULL; i <= EPD_PHONENUM; ++i) {
334 		int sl = strlen(endp_class_names[i]);
335 		if (strncasecmp(str, endp_class_names[i], sl) == 0) {
336 			str += sl;
337 			break;
338 		}
339 	}
340 	if (i > EPD_PHONENUM) {
341 		/* not a class name, try a decimal class number */
342 		i = strtol(str, &endp, 10);
343 		if (endp == str) {
344 			option_error("cannot parse endpoint class in \"%s\"",
345 			    str);
346 			return 0;	/* can't parse class number */
347 		}
348 		str = endp;
349 	}
350 	ep->class = i;
351 	if (*str == 0) {
352 		ep->length = 0;
353 		return 1;
354 	}
355 	if (*str != ':' && *str != '.') {
356 		option_error("invalid class/value separator '%c'", *str);
357 		return 0;
358 	}
359 	++str;
360 
361 	if (i == EPD_IP) {
362 		u_int32_t addr;
363 		i = parse_dotted_ip(str, &addr);
364 		if (i == 0 || str[i] != 0)
365 			return 0;
366 		set_ip_epdisc(ep, addr);
367 		dbglog("str_to_epdisc -> %s", epdisc_to_str(ep));
368 		return 1;
369 	}
370 	if (i == EPD_MAC &&
371 	    get_if_hwaddr(ep->value, sizeof(ep->value), str) >= 0) {
372 		ep->length = 6;
373 		dbglog("str_to_epdisc -> %s", epdisc_to_str(ep));
374 		return 1;
375 	}
376 
377 	p = str;
378 	for (l = 0; l < MAX_ENDP_LEN; ++l) {
379 		if (*str == 0)
380 			break;
381 		if (p <= str)
382 			for (p = str; isxdigit(*p); ++p)
383 				;
384 		i = p - str;
385 		if (i == 0) {
386 			option_error("no valid hex digits in \"%s\"", str);
387 			return 0;
388 		}
389 		ep->value[l] = hexc_val(*str++);
390 		if ((i & 1) == 0)
391 			ep->value[l] = (ep->value[l] << 4) + hexc_val(*str++);
392 		if (*str == ':' || *str == '.')
393 			++str;
394 	}
395 	if (*str != 0) {
396 		option_error("too many bytes in value; max is %d",
397 		    MAX_ENDP_LEN);
398 		return 0;
399 	}
400 	if (ep->class == EPD_MAC && l != 6) {
401 		option_error("bad endpoint; MAC address must have 6 bytes");
402 		return 0;
403 	}
404 	ep->length = l;
405 	dbglog("str_to_epdisc -> %s", epdisc_to_str(ep));
406 	return 1;
407 }
408