xref: /netbsd/usr.sbin/bootp/common/dovend.c (revision c4a72b64)
1 /*	$NetBSD: dovend.c,v 1.5 2002/07/14 00:26:16 wiz Exp $	*/
2 
3 #include <sys/cdefs.h>
4 #ifndef lint
5 __RCSID("$NetBSD: dovend.c,v 1.5 2002/07/14 00:26:16 wiz Exp $");
6 #endif
7 
8 /*
9  * dovend.c : Inserts all but the first few vendor options.
10  */
11 
12 #include <sys/types.h>
13 
14 #include <netinet/in.h>
15 #include <arpa/inet.h>			/* inet_ntoa */
16 
17 #include <stdlib.h>
18 #include <stdio.h>
19 #include <string.h>
20 #include <errno.h>
21 #include <syslog.h>
22 
23 #ifndef USE_BFUNCS
24 # include <memory.h>
25 /* Yes, memcpy is OK here (no overlapped copies). */
26 # define bcopy(a,b,c)    memcpy(b,a,c)
27 # define bzero(p,l)      memset(p,0,l)
28 # define bcmp(a,b,c)     memcmp(a,b,c)
29 # define index           strchr
30 #endif
31 
32 #include "bootp.h"
33 #include "bootpd.h"
34 #include "report.h"
35 #include "dovend.h"
36 
37 PRIVATE int insert_generic(struct shared_bindata *, byte **, int *);
38 
39 /*
40  * Insert the 2nd part of the options into an option buffer.
41  * Return amount of space used.
42  *
43  * This inserts everything EXCEPT:
44  *   magic cookie, subnet mask, gateway, bootsize, extension file
45  * Those are handled separately (in bootpd.c) to allow this function
46  * to be shared between bootpd and bootpef.
47  *
48  * When an "extension file" is in use, the options inserted by
49  * this function go into the exten_file, not the bootp response.
50  */
51 
52 int
53 dovend_rfc1497(struct host *hp, byte *buf, int len)
54 {
55 	int bytesleft = len;
56 	byte *vp = buf;
57 #if 0
58 	char *tmpstr;
59 #endif
60 
61 	static const char noroom[] = "%s: No room for \"%s\" option";
62 #define	NEED(LEN, MSG) do                       \
63 		if (bytesleft < (LEN)) {         	    \
64 			report(LOG_NOTICE, noroom,          \
65 				   hp->hostname->string, MSG);  \
66 			return (vp - buf);                  \
67 		} while (0)
68 
69 	/*
70 	 * Note that the following have already been inserted:
71 	 *   magic_cookie, subnet_mask, gateway, bootsize
72 	 *
73 	 * The remaining options are inserted in order of importance.
74 	 * (Of course the importance of each is a matter of opinion.)
75 	 * The option insertion order should probably be configurable.
76 	 *
77 	 * This is the order used in the NetBSD version.  Can anyone
78 	 * explain why the time_offset and swap_server are first?
79 	 * Also, why is the hostname so far down the list?  -gwr
80 	 */
81 
82 	if (hp->flags.time_offset) {
83 		NEED(6, "to");
84 		*vp++ = TAG_TIME_OFFSET;/* -1 byte  */
85 		*vp++ = 4;				/* -1 byte  */
86 		insert_u_long(htonl(hp->time_offset), &vp);	/* -4 bytes */
87 		bytesleft -= 6;
88 	}
89 	/*
90 	 * swap server, root path, dump path
91 	 */
92 	if (hp->flags.swap_server) {
93 		NEED(6, "sw");
94 		/* There is just one SWAP_SERVER, so it is not an iplist. */
95 		*vp++ = TAG_SWAP_SERVER;/* -1 byte  */
96 		*vp++ = 4;				/* -1 byte  */
97 		insert_u_long(hp->swap_server.s_addr, &vp);	/* -4 bytes */
98 		bytesleft -= 6;			/* Fix real count */
99 	}
100 	if (hp->flags.root_path) {
101 		/*
102 		 * Check for room for root_path.  Add 2 to account for
103 		 * TAG_ROOT_PATH and length.
104 		 */
105 		len = strlen(hp->root_path->string);
106 		NEED((len + 2), "rp");
107 		*vp++ = TAG_ROOT_PATH;
108 		*vp++ = (byte) (len & 0xFF);
109 		bcopy(hp->root_path->string, vp, len);
110 		vp += len;
111 		bytesleft -= len + 2;
112 	}
113 	if (hp->flags.dump_file) {
114 		/*
115 		 * Check for room for dump_file.  Add 2 to account for
116 		 * TAG_DUMP_FILE and length.
117 		 */
118 		len = strlen(hp->dump_file->string);
119 		NEED((len + 2), "df");
120 		*vp++ = TAG_DUMP_FILE;
121 		*vp++ = (byte) (len & 0xFF);
122 		bcopy(hp->dump_file->string, vp, len);
123 		vp += len;
124 		bytesleft -= len + 2;
125 	}
126 	/*
127 	 * DNS server and domain
128 	 */
129 	if (hp->flags.domain_server) {
130 		if (insert_ip(TAG_DOMAIN_SERVER,
131 					  hp->domain_server,
132 					  &vp, &bytesleft))
133 			NEED(8, "ds");
134 	}
135 	if (hp->flags.domain_name) {
136 		/*
137 		 * Check for room for domain_name.  Add 2 to account for
138 		 * TAG_DOMAIN_NAME and length.
139 		 */
140 		len = strlen(hp->domain_name->string);
141 		NEED((len + 2), "dn");
142 		*vp++ = TAG_DOMAIN_NAME;
143 		*vp++ = (byte) (len & 0xFF);
144 		bcopy(hp->domain_name->string, vp, len);
145 		vp += len;
146 		bytesleft -= len + 2;
147 	}
148 	/*
149 	 * NIS (YP) server and domain
150 	 */
151 	if (hp->flags.nis_server) {
152 		if (insert_ip(TAG_NIS_SERVER,
153 					  hp->nis_server,
154 					  &vp, &bytesleft))
155 			NEED(8, "ds");
156 	}
157 	if (hp->flags.nis_domain) {
158 		/*
159 		 * Check for room for nis_domain.  Add 2 to account for
160 		 * TAG_NIS_DOMAIN and length.
161 		 */
162 		len = strlen(hp->nis_domain->string);
163 		NEED((len + 2), "dn");
164 		*vp++ = TAG_NIS_DOMAIN;
165 		*vp++ = (byte) (len & 0xFF);
166 		bcopy(hp->nis_domain->string, vp, len);
167 		vp += len;
168 		bytesleft -= len + 2;
169 	}
170 	/* IEN 116 name server */
171 	if (hp->flags.name_server) {
172 		if (insert_ip(TAG_NAME_SERVER,
173 					  hp->name_server,
174 					  &vp, &bytesleft))
175 			NEED(8, "ns");
176 	}
177 	if (hp->flags.rlp_server) {
178 		if (insert_ip(TAG_RLP_SERVER,
179 					  hp->rlp_server,
180 					  &vp, &bytesleft))
181 			NEED(8, "rl");
182 	}
183 	/* Time server (RFC 868) */
184 	if (hp->flags.time_server) {
185 		if (insert_ip(TAG_TIME_SERVER,
186 					  hp->time_server,
187 					  &vp, &bytesleft))
188 			NEED(8, "ts");
189 	}
190 	/* NTP (time) Server (RFC 1129) */
191 	if (hp->flags.ntp_server) {
192 		if (insert_ip(TAG_NTP_SERVER,
193 					  hp->ntp_server,
194 					  &vp, &bytesleft))
195 			NEED(8, "ts");
196 	}
197 	/*
198 	 * I wonder:  If the hostname were "promoted" into the BOOTP
199 	 * response part, might these "extension" files possibly be
200 	 * shared between several clients?
201 	 *
202 	 * Also, why not just use longer BOOTP packets with all the
203 	 * additional length used as option data.  This bootpd version
204 	 * already supports that feature by replying with the same
205 	 * packet length as the client request packet. -gwr
206 	 */
207 	if (hp->flags.name_switch && hp->flags.send_name) {
208 		/*
209 		 * Check for room for hostname.  Add 2 to account for
210 		 * TAG_HOST_NAME and length.
211 		 */
212 		len = strlen(hp->hostname->string);
213 #if 0
214 		/*
215 		 * XXX - Too much magic.  The user can always set the hostname
216 		 * to the short version in the bootptab file. -gwr
217 		 */
218 		if ((len + 2) > bytesleft) {
219 			/*
220 			 * Not enough room for full (domain-qualified) hostname, try
221 			 * stripping it down to just the first field (host).
222 			 */
223 			tmpstr = hp->hostname->string;
224 			len = 0;
225 			while (*tmpstr && (*tmpstr != '.')) {
226 				tmpstr++;
227 				len++;
228 			}
229 		}
230 #endif
231 		NEED((len + 2), "hn");
232 		*vp++ = TAG_HOST_NAME;
233 		*vp++ = (byte) (len & 0xFF);
234 		bcopy(hp->hostname->string, vp, len);
235 		vp += len;
236 		bytesleft -= len + 2;
237 	}
238 	/*
239 	 * The rest of these are less important, so they go last.
240 	 */
241 	if (hp->flags.lpr_server) {
242 		if (insert_ip(TAG_LPR_SERVER,
243 					  hp->lpr_server,
244 					  &vp, &bytesleft))
245 			NEED(8, "lp");
246 	}
247 	if (hp->flags.cookie_server) {
248 		if (insert_ip(TAG_COOKIE_SERVER,
249 					  hp->cookie_server,
250 					  &vp, &bytesleft))
251 			NEED(8, "cs");
252 	}
253 	if (hp->flags.log_server) {
254 		if (insert_ip(TAG_LOG_SERVER,
255 					  hp->log_server,
256 					  &vp, &bytesleft))
257 			NEED(8, "lg");
258 	}
259 	/*
260 	 * XXX - Add new tags here (to insert options)
261 	 */
262 	if (hp->flags.generic) {
263 		if (insert_generic(hp->generic, &vp, &bytesleft))
264 			NEED(64, "(generic)");
265 	}
266 	/*
267 	 * The end marker is inserted by the caller.
268 	 */
269 	return (vp - buf);
270 #undef	NEED
271 }								/* dovend_rfc1497 */
272 
273 
274 
275 /*
276  * Insert a tag value, a length value, and a list of IP addresses into the
277  * memory buffer indirectly pointed to by "dest".  "tag" is the RFC1048 tag
278  * number to use, "iplist" is a pointer to a list of IP addresses
279  * (struct in_addr_list), and "bytesleft" points to an integer which
280  * indicates the size of the "dest" buffer.
281  *
282  * Return zero if everything fits.
283  *
284  * This is used to fill the vendor-specific area of a bootp packet in
285  * conformance to RFC1048.
286  */
287 
288 int
289 insert_ip(byte tag, struct in_addr_list *iplist, byte **dest, int *bytesleft)
290 {
291 	struct in_addr *addrptr;
292 	unsigned addrcount = 1;
293 	byte *d;
294 
295 	if (iplist == NULL)
296 		return (0);
297 
298 	if (*bytesleft >= 6) {
299 		d = *dest;				/* Save pointer for later */
300 		**dest = tag;
301 		(*dest) += 2;
302 		(*bytesleft) -= 2;		/* Account for tag and length */
303 		addrptr = iplist->addr;
304 		addrcount = iplist->addrcount;
305 		while ((*bytesleft >= 4) && (addrcount > 0)) {
306 			insert_u_long(addrptr->s_addr, dest);
307 			addrptr++;
308 			addrcount--;
309 			(*bytesleft) -= 4;	/* Four bytes per address */
310 		}
311 		d[1] = (byte) ((*dest - d - 2) & 0xFF);
312 	}
313 	return (addrcount);
314 }
315 
316 
317 
318 /*
319  * Insert generic data into a bootp packet.  The data is assumed to already
320  * be in RFC1048 format.  It is inserted using a first-fit algorithm which
321  * attempts to insert as many tags as possible.  Tags and data which are
322  * too large to fit are skipped; any remaining tags are tried until they
323  * have all been exhausted.
324  * Return zero if everything fits.
325  */
326 
327 static int
328 insert_generic(struct shared_bindata *gendata, byte **buff, int *bytesleft)
329 {
330 	byte *srcptr;
331 	int length, numbytes;
332 	int skipped = 0;
333 
334 	if (gendata == NULL)
335 		return (0);
336 
337 	srcptr = gendata->data;
338 	length = gendata->length;
339 	while ((length > 0) && (*bytesleft > 0)) {
340 		switch (*srcptr) {
341 		case TAG_END:
342 			length = 0;			/* Force an exit on next iteration */
343 			break;
344 		case TAG_PAD:
345 			*(*buff)++ = *srcptr++;
346 			(*bytesleft)--;
347 			length--;
348 			break;
349 		default:
350 			numbytes = srcptr[1] + 2;
351 			if (*bytesleft < numbytes)
352 				skipped += numbytes;
353 			else {
354 				bcopy(srcptr, *buff, numbytes);
355 				(*buff) += numbytes;
356 				(*bytesleft) -= numbytes;
357 			}
358 			srcptr += numbytes;
359 			length -= numbytes;
360 			break;
361 		}
362 	} /* while */
363 	return (skipped);
364 }
365 
366 /*
367  * Insert the unsigned long "value" into memory starting at the byte
368  * pointed to by the byte pointer (*dest).  (*dest) is updated to
369  * point to the next available byte.
370  *
371  * Since it is desirable to internally store network addresses in network
372  * byte order (in struct in_addr's), this routine expects longs to be
373  * passed in network byte order.
374  *
375  * However, due to the nature of the main algorithm, the long must be in
376  * host byte order, thus necessitating the use of ntohl() first.
377  */
378 
379 void
380 insert_u_long(u_int32 value, byte **dest)
381 {
382 	byte *temp;
383 	int n;
384 
385 	value = ntohl(value);		/* Must use host byte order here */
386 	temp = (*dest += 4);
387 	for (n = 4; n > 0; n--) {
388 		*--temp = (byte) (value & 0xFF);
389 		value >>= 8;
390 	}
391 	/* Final result is network byte order */
392 }
393 
394 /*
395  * Local Variables:
396  * tab-width: 4
397  * c-indent-level: 4
398  * c-argdecl-indent: 4
399  * c-continued-statement-offset: 4
400  * c-continued-brace-offset: -4
401  * c-label-offset: -4
402  * c-brace-offset: 0
403  * End:
404  */
405