bootp.c revision 1.5 
1/*	$OpenBSD: bootp.c,v 1.5 1996/10/16 14:18:35 mickey Exp $	*/
2/*	$NetBSD: bootp.c,v 1.7 1995/09/18 21:19:20 pk Exp $	*/
3
4/*
5 * Copyright (c) 1992 Regents of the University of California.
6 * All rights reserved.
7 *
8 * This software was developed by the Computer Systems Engineering group
9 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
10 * contributed to Berkeley.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 *    notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 *    notice, this list of conditions and the following disclaimer in the
19 *    documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 *    must display the following acknowledgement:
22 *	This product includes software developed by the University of
23 *	California, Lawrence Berkeley Laboratory and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 *    may be used to endorse or promote products derived from this software
26 *    without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 * @(#) Header: bootp.c,v 1.4 93/09/11 03:13:51 leres Exp  (LBL)
41 */
42
43#include <sys/types.h>
44#include <netinet/in.h>
45#include <netinet/in_systm.h>
46
47#include "stand.h"
48#include "net.h"
49#include "netif.h"
50#include "bootp.h"
51
52static n_long	nmask, smask;
53
54static time_t	bot;
55
56static	char vm_rfc1048[4] = VM_RFC1048;
57static	char vm_cmu[4] = VM_CMU;
58
59/* Local forwards */
60static	ssize_t bootpsend __P((struct iodesc *, void *, size_t));
61static	ssize_t bootprecv __P((struct iodesc *, void *, size_t, time_t));
62static	void vend_cmu __P((u_char *));
63static	void vend_rfc1048 __P((u_char *, u_int));
64
65/* Fetch required bootp infomation */
66void
67bootp(sock)
68	int sock;
69{
70	struct iodesc *d;
71	register struct bootp *bp;
72	struct {
73		u_char header[HEADER_SIZE];
74		struct bootp wbootp;
75	} wbuf;
76	struct {
77		u_char header[HEADER_SIZE];
78		struct bootp rbootp;
79	} rbuf;
80
81#ifdef BOOTP_DEBUG
82 	if (debug)
83		printf("bootp: socket=%d\n", sock);
84#endif
85	if (!bot)
86		bot = getsecs();
87
88	if (!(d = socktodesc(sock))) {
89		printf("bootp: bad socket. %d\n", sock);
90		return;
91	}
92#ifdef BOOTP_DEBUG
93 	if (debug)
94		printf("bootp: d=%x\n", (u_int)d);
95#endif
96
97	bp = &wbuf.wbootp;
98	bzero(bp, sizeof(*bp));
99
100	bp->bp_op = BOOTREQUEST;
101	bp->bp_htype = HTYPE_ETHERNET;	/* 10Mb Ethernet (48 bits) */
102	bp->bp_hlen = 6;
103	bp->bp_xid = htonl(d->xid);
104	MACPY(d->myea, bp->bp_chaddr);
105	bzero(bp->bp_file, sizeof(bp->bp_file));
106	bcopy(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048));
107
108	d->myip = myip;
109	d->myport = htons(IPPORT_BOOTPC);
110	d->destip.s_addr = INADDR_BROADCAST;
111	d->destport = htons(IPPORT_BOOTPS);
112
113	(void)sendrecv(d,
114	    bootpsend, bp, sizeof(*bp),
115	    bootprecv, &rbuf.rbootp, sizeof(rbuf.rbootp));
116
117	/* Bump xid so next request will be unique. */
118	++d->xid;
119}
120
121/* Transmit a bootp request */
122static ssize_t
123bootpsend(d, pkt, len)
124	register struct iodesc *d;
125	register void *pkt;
126	register size_t len;
127{
128	register struct bootp *bp;
129
130#ifdef BOOTP_DEBUG
131	if (debug)
132		printf("bootpsend: d=%x called.\n", (u_int)d);
133#endif
134
135	bp = pkt;
136	bp->bp_secs = htons((u_short)(getsecs() - bot));
137
138#ifdef BOOTP_DEBUG
139	if (debug)
140		printf("bootpsend: calling sendudp\n");
141#endif
142
143	return (sendudp(d, pkt, len));
144}
145
146/* Returns 0 if this is the packet we're waiting for else -1 (and errno == 0) */
147static ssize_t
148bootprecv(d, pkt, len, tleft)
149	register struct iodesc *d;
150	register void *pkt;
151	register size_t len;
152	time_t tleft;
153{
154	register ssize_t n;
155	register struct bootp *bp;
156
157#ifdef BOOTP_DEBUG
158	if (debug)
159		printf("bootprecv: called\n");
160#endif
161
162	n = readudp(d, pkt, len, tleft);
163	if (n == -1 || n < sizeof(struct bootp))
164		goto bad;
165
166	bp = (struct bootp *)pkt;
167
168#ifdef BOOTP_DEBUG
169	if (debug)
170		printf("bootprecv: checked.  bp = 0x%x, n = %d\n",
171		    (unsigned)bp, n);
172#endif
173	if (bp->bp_xid != htonl(d->xid)) {
174#ifdef BOOTP_DEBUG
175		if (debug) {
176			printf("bootprecv: expected xid 0x%lx, got 0x%lx\n",
177			    d->xid, ntohl(bp->bp_xid));
178		}
179#endif
180		goto bad;
181	}
182
183#ifdef BOOTP_DEBUG
184	if (debug)
185		printf("bootprecv: got one!\n");
186#endif
187
188	/* Pick up our ip address (and natural netmask) */
189	myip = d->myip = bp->bp_yiaddr;
190#ifdef BOOTP_DEBUG
191	if (debug)
192		printf("our ip address is %s\n", inet_ntoa(d->myip));
193#endif
194	if (IN_CLASSA(d->myip.s_addr))
195		nmask = IN_CLASSA_NET;
196	else if (IN_CLASSB(d->myip.s_addr))
197		nmask = IN_CLASSB_NET;
198	else
199		nmask = IN_CLASSC_NET;
200#ifdef BOOTP_DEBUG
201	if (debug)
202		printf("'native netmask' is %s\n", intoa(nmask));
203#endif
204
205	/* Pick up root or swap server address and file spec. */
206	if (bp->bp_siaddr.s_addr != 0)
207		rootip = bp->bp_siaddr;
208	if (bp->bp_file[0] != '\0') {
209		strncpy(bootfile, (char *)bp->bp_file, sizeof(bootfile));
210		bootfile[sizeof(bootfile) - 1] = '\0';
211	}
212
213	/* Suck out vendor info */
214	if (bcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0)
215		vend_cmu(bp->bp_vend);
216	else if (bcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0)
217		vend_rfc1048(bp->bp_vend, sizeof(bp->bp_vend));
218	else
219		printf("bootprecv: unknown vendor 0x%lx\n", (long)bp->bp_vend);
220
221	/* Check subnet mask against net mask; toss if bogus */
222	if ((nmask & smask) != nmask) {
223#ifdef BOOTP_DEBUG
224		if (debug)
225			printf("subnet mask (%s) bad\n", intoa(smask));
226#endif
227		smask = 0;
228	}
229
230	/* Get subnet (or natural net) mask */
231	netmask = nmask;
232	if (smask)
233		netmask = smask;
234#ifdef BOOTP_DEBUG
235	if (debug)
236		printf("mask: %s\n", intoa(netmask));
237#endif
238
239	/* We need a gateway if root or swap is on a different net */
240	if (!SAMENET(d->myip, rootip, netmask)) {
241#ifdef BOOTP_DEBUG
242		if (debug)
243			printf("need gateway for root ip\n");
244#endif
245	}
246
247	if (!SAMENET(d->myip, swapip, netmask)) {
248#ifdef BOOTP_DEBUG
249		if (debug)
250			printf("need gateway for swap ip\n");
251#endif
252	}
253
254	/* Toss gateway if on a different net */
255	if (!SAMENET(d->myip, gateip, netmask)) {
256#ifdef BOOTP_DEBUG
257		if (debug)
258			printf("gateway ip (%s) bad\n", inet_ntoa(gateip));
259#endif
260		gateip.s_addr = 0;
261	}
262
263	return (n);
264
265bad:
266	errno = 0;
267	return (-1);
268}
269
270static void
271vend_cmu(cp)
272	u_char *cp;
273{
274	register struct cmu_vend *vp;
275
276#ifdef BOOTP_DEBUG
277	if (debug)
278		printf("vend_cmu bootp info.\n");
279#endif
280	vp = (struct cmu_vend *)cp;
281
282	if (vp->v_smask.s_addr != 0) {
283		smask = vp->v_smask.s_addr;
284	}
285	if (vp->v_dgate.s_addr != 0) {
286		gateip = vp->v_dgate;
287	}
288}
289
290static void
291vend_rfc1048(cp, len)
292	register u_char *cp;
293	u_int len;
294{
295	register u_char *ep;
296	register int size;
297	register u_char tag;
298
299#ifdef BOOTP_DEBUG
300	if (debug)
301		printf("vend_rfc1048 bootp info. len=%d\n", len);
302#endif
303	ep = cp + len;
304
305	/* Step over magic cookie */
306	cp += sizeof(long);
307
308	while (cp < ep) {
309		tag = *cp++;
310		size = *cp++;
311		if (tag == TAG_END)
312			break;
313
314		if (tag == TAG_SUBNET_MASK) {
315			bcopy(cp, &smask, sizeof(smask));
316		}
317		if (tag == TAG_GATEWAY) {
318			bcopy(cp, &gateip.s_addr, sizeof(gateip.s_addr));
319		}
320		if (tag == TAG_SWAPSERVER) {
321			bcopy(cp, &swapip.s_addr, sizeof(swapip.s_addr));
322		}
323		if (tag == TAG_DOMAIN_SERVER) {
324			bcopy(cp, &nameip.s_addr, sizeof(nameip.s_addr));
325		}
326		if (tag == TAG_ROOTPATH) {
327			strncpy(rootpath, (char *)cp, sizeof(rootpath));
328			rootpath[size] = '\0';
329		}
330		if (tag == TAG_HOSTNAME) {
331			strncpy(hostname, (char *)cp, sizeof(hostname));
332			hostname[size] = '\0';
333		}
334		if (tag == TAG_DOMAINNAME) {
335			strncpy(domainname, (char *)cp, sizeof(domainname));
336			domainname[size] = '\0';
337		}
338		cp += size;
339	}
340}
341