bootp.c revision 1.12 
1/*	$OpenBSD: bootp.c,v 1.12 2006/02/06 17:37:28 jmc Exp $	*/
2/*	$NetBSD: bootp.c,v 1.10 1996/10/13 02:28:59 christos 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 <sys/socket.h>
45#include <netinet/in.h>
46#include <netinet/in_systm.h>
47
48#include "stand.h"
49#include "net.h"
50#include "netif.h"
51#include "bootp.h"
52
53static n_long	nmask, smask;
54
55static time_t	bot;
56
57static	char vm_rfc1048[4] = VM_RFC1048;
58static	char vm_cmu[4] = VM_CMU;
59
60/* Local forwards */
61static	ssize_t bootpsend(struct iodesc *, void *, size_t);
62static	ssize_t bootprecv(struct iodesc *, void *, size_t, time_t);
63static	void vend_cmu(u_char *);
64static	void vend_rfc1048(u_char *, u_int);
65
66/* Fetch required bootp information */
67void
68bootp(int sock)
69{
70	struct iodesc *d;
71	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(struct iodesc *d, void *pkt, size_t len)
124{
125	struct bootp *bp;
126
127#ifdef BOOTP_DEBUG
128	if (debug)
129		printf("bootpsend: d=%x called.\n", (u_int)d);
130#endif
131
132	bp = pkt;
133	bp->bp_secs = htons((u_short)(getsecs() - bot));
134
135#ifdef BOOTP_DEBUG
136	if (debug)
137		printf("bootpsend: calling sendudp\n");
138#endif
139
140	return (sendudp(d, pkt, len));
141}
142
143/* Returns 0 if this is the packet we're waiting for else -1 (and errno == 0) */
144static ssize_t
145bootprecv(struct iodesc *d, void *pkt, size_t len, time_t tleft)
146{
147	ssize_t n;
148	struct bootp *bp;
149
150#ifdef BOOTP_DEBUG
151	if (debug)
152		printf("bootprecv: called\n");
153#endif
154
155	n = readudp(d, pkt, len, tleft);
156	if (n < 0 || (size_t)n < sizeof(struct bootp))
157		goto bad;
158
159	bp = (struct bootp *)pkt;
160
161#ifdef BOOTP_DEBUG
162	if (debug)
163		printf("bootprecv: checked.  bp = 0x%x, n = %d\n",
164		    (unsigned)bp, n);
165#endif
166	if (bp->bp_xid != htonl(d->xid)) {
167#ifdef BOOTP_DEBUG
168		if (debug) {
169			printf("bootprecv: expected xid 0x%lx, got 0x%lx\n",
170			    d->xid, ntohl(bp->bp_xid));
171		}
172#endif
173		goto bad;
174	}
175
176#ifdef BOOTP_DEBUG
177	if (debug)
178		printf("bootprecv: got one!\n");
179#endif
180
181	/* Pick up our ip address (and natural netmask) */
182	myip = d->myip = bp->bp_yiaddr;
183#ifdef BOOTP_DEBUG
184	if (debug)
185		printf("our ip address is %s\n", inet_ntoa(d->myip));
186#endif
187	if (IN_CLASSA(d->myip.s_addr))
188		nmask = IN_CLASSA_NET;
189	else if (IN_CLASSB(d->myip.s_addr))
190		nmask = IN_CLASSB_NET;
191	else
192		nmask = IN_CLASSC_NET;
193#ifdef BOOTP_DEBUG
194	if (debug)
195		printf("'native netmask' is %s\n", intoa(nmask));
196#endif
197
198	/* Pick up root or swap server address and file spec. */
199	if (bp->bp_siaddr.s_addr != 0)
200		rootip = bp->bp_siaddr;
201	if (bp->bp_file[0] != '\0') {
202		strncpy(bootfile, (char *)bp->bp_file, sizeof(bootfile));
203		bootfile[sizeof(bootfile) - 1] = '\0';
204	}
205
206	/* Suck out vendor info */
207	if (bcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0)
208		vend_cmu(bp->bp_vend);
209	else if (bcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0)
210		vend_rfc1048(bp->bp_vend, sizeof(bp->bp_vend));
211	else
212		printf("bootprecv: unknown vendor 0x%lx\n", (long)bp->bp_vend);
213
214	/* Check subnet mask against net mask; toss if bogus */
215	if ((nmask & smask) != nmask) {
216#ifdef BOOTP_DEBUG
217		if (debug)
218			printf("subnet mask (%s) bad\n", intoa(smask));
219#endif
220		smask = 0;
221	}
222
223	/* Get subnet (or natural net) mask */
224	netmask = nmask;
225	if (smask)
226		netmask = smask;
227#ifdef BOOTP_DEBUG
228	if (debug)
229		printf("mask: %s\n", intoa(netmask));
230#endif
231
232	/* We need a gateway if root or swap is on a different net */
233	if (!SAMENET(d->myip, rootip, netmask)) {
234#ifdef BOOTP_DEBUG
235		if (debug)
236			printf("need gateway for root ip\n");
237#endif
238	}
239
240	if (!SAMENET(d->myip, swapip, netmask)) {
241#ifdef BOOTP_DEBUG
242		if (debug)
243			printf("need gateway for swap ip\n");
244#endif
245	}
246
247	/* Toss gateway if on a different net */
248	if (!SAMENET(d->myip, gateip, netmask)) {
249#ifdef BOOTP_DEBUG
250		if (debug)
251			printf("gateway ip (%s) bad\n", inet_ntoa(gateip));
252#endif
253		gateip.s_addr = 0;
254	}
255
256	return (n);
257
258bad:
259	errno = 0;
260	return (-1);
261}
262
263static void
264vend_cmu(u_char *cp)
265{
266	struct cmu_vend *vp;
267
268#ifdef BOOTP_DEBUG
269	if (debug)
270		printf("vend_cmu bootp info.\n");
271#endif
272	vp = (struct cmu_vend *)cp;
273
274	if (vp->v_smask.s_addr != 0)
275		smask = vp->v_smask.s_addr;
276	if (vp->v_dgate.s_addr != 0)
277		gateip = vp->v_dgate;
278}
279
280static void
281vend_rfc1048(u_char *cp, u_int len)
282{
283	u_char *ep;
284	int size;
285	u_char tag;
286
287#ifdef BOOTP_DEBUG
288	if (debug)
289		printf("vend_rfc1048 bootp info. len=%d\n", len);
290#endif
291	ep = cp + len;
292
293	/* Step over magic cookie */
294	cp += sizeof(int);
295
296	while (cp < ep) {
297		tag = *cp++;
298		size = *cp++;
299		if (tag == TAG_END)
300			break;
301
302		if (tag == TAG_SUBNET_MASK)
303			bcopy(cp, &smask, sizeof(smask));
304		if (tag == TAG_GATEWAY)
305			bcopy(cp, &gateip.s_addr, sizeof(gateip.s_addr));
306		if (tag == TAG_SWAPSERVER)
307			bcopy(cp, &swapip.s_addr, sizeof(swapip.s_addr));
308		if (tag == TAG_DOMAIN_SERVER)
309			bcopy(cp, &nameip.s_addr, sizeof(nameip.s_addr));
310		if (tag == TAG_ROOTPATH) {
311			strncpy(rootpath, (char *)cp, sizeof(rootpath));
312			rootpath[size] = '\0';
313		}
314		if (tag == TAG_HOSTNAME) {
315			strncpy(hostname, (char *)cp, sizeof(hostname));
316			hostname[size] = '\0';
317		}
318		if (tag == TAG_DOMAINNAME) {
319			strncpy(domainname, (char *)cp, sizeof(domainname));
320			domainname[size] = '\0';
321		}
322		cp += size;
323	}
324}
325