bootp.c revision 1.14 
1/*	$OpenBSD: bootp.c,v 1.14 2014/07/13 15:31:20 mpi 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
47#include "stand.h"
48#include "net.h"
49#include "netif.h"
50#include "bootp.h"
51
52static u_int32_t	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(struct iodesc *, void *, size_t);
61static	ssize_t bootprecv(struct iodesc *, void *, size_t, time_t);
62static	void vend_cmu(u_char *);
63static	void vend_rfc1048(u_char *, u_int);
64
65/* Fetch required bootp information */
66void
67bootp(int sock)
68{
69	struct iodesc *d;
70	struct bootp *bp;
71	struct {
72		struct packet_header header;
73		struct bootp wbootp;
74	} wbuf;
75	struct {
76		struct packet_header header;
77		struct bootp rbootp;
78	} rbuf;
79
80#ifdef BOOTP_DEBUG
81	if (debug)
82		printf("bootp: socket=%d\n", sock);
83#endif
84	if (!bot)
85		bot = getsecs();
86
87	if (!(d = socktodesc(sock))) {
88		printf("bootp: bad socket. %d\n", sock);
89		return;
90	}
91#ifdef BOOTP_DEBUG
92	if (debug)
93		printf("bootp: d=%x\n", (u_int)d);
94#endif
95
96	bp = &wbuf.wbootp;
97	bzero(bp, sizeof(*bp));
98
99	bp->bp_op = BOOTREQUEST;
100	bp->bp_htype = HTYPE_ETHERNET;	/* 10Mb Ethernet (48 bits) */
101	bp->bp_hlen = 6;
102	bp->bp_xid = htonl(d->xid);
103	MACPY(d->myea, bp->bp_chaddr);
104	bzero(bp->bp_file, sizeof(bp->bp_file));
105	bcopy(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048));
106
107	d->myip = myip;
108	d->myport = htons(IPPORT_BOOTPC);
109	d->destip.s_addr = INADDR_BROADCAST;
110	d->destport = htons(IPPORT_BOOTPS);
111
112	(void)sendrecv(d,
113	    bootpsend, bp, sizeof(*bp),
114	    bootprecv, &rbuf.rbootp, sizeof(rbuf.rbootp));
115
116	/* Bump xid so next request will be unique. */
117	++d->xid;
118}
119
120/* Transmit a bootp request */
121static ssize_t
122bootpsend(struct iodesc *d, void *pkt, size_t len)
123{
124	struct bootp *bp;
125
126#ifdef BOOTP_DEBUG
127	if (debug)
128		printf("bootpsend: d=%x called.\n", (u_int)d);
129#endif
130
131	bp = pkt;
132	bp->bp_secs = htons((u_short)(getsecs() - bot));
133
134#ifdef BOOTP_DEBUG
135	if (debug)
136		printf("bootpsend: calling sendudp\n");
137#endif
138
139	return (sendudp(d, pkt, len));
140}
141
142/* Returns 0 if this is the packet we're waiting for else -1 (and errno == 0) */
143static ssize_t
144bootprecv(struct iodesc *d, void *pkt, size_t len, time_t tleft)
145{
146	ssize_t n;
147	struct bootp *bp;
148
149#ifdef BOOTP_DEBUG
150	if (debug)
151		printf("bootprecv: called\n");
152#endif
153
154	n = readudp(d, pkt, len, tleft);
155	if (n < 0 || (size_t)n < sizeof(struct bootp))
156		goto bad;
157
158	bp = (struct bootp *)pkt;
159
160#ifdef BOOTP_DEBUG
161	if (debug)
162		printf("bootprecv: checked.  bp = 0x%x, n = %d\n",
163		    (unsigned)bp, n);
164#endif
165	if (bp->bp_xid != htonl(d->xid)) {
166#ifdef BOOTP_DEBUG
167		if (debug) {
168			printf("bootprecv: expected xid 0x%lx, got 0x%lx\n",
169			    d->xid, ntohl(bp->bp_xid));
170		}
171#endif
172		goto bad;
173	}
174
175#ifdef BOOTP_DEBUG
176	if (debug)
177		printf("bootprecv: got one!\n");
178#endif
179
180	/* Pick up our ip address (and natural netmask) */
181	myip = d->myip = bp->bp_yiaddr;
182#ifdef BOOTP_DEBUG
183	if (debug)
184		printf("our ip address is %s\n", inet_ntoa(d->myip));
185#endif
186	if (IN_CLASSA(d->myip.s_addr))
187		nmask = IN_CLASSA_NET;
188	else if (IN_CLASSB(d->myip.s_addr))
189		nmask = IN_CLASSB_NET;
190	else
191		nmask = IN_CLASSC_NET;
192#ifdef BOOTP_DEBUG
193	if (debug)
194		printf("'native netmask' is %s\n", intoa(nmask));
195#endif
196
197	/* Pick up root or swap server address and file spec. */
198	if (bp->bp_siaddr.s_addr != 0)
199		rootip = bp->bp_siaddr;
200	if (bp->bp_file[0] != '\0') {
201		strncpy(bootfile, (char *)bp->bp_file, sizeof(bootfile));
202		bootfile[sizeof(bootfile) - 1] = '\0';
203	}
204
205	/* Suck out vendor info */
206	if (bcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0)
207		vend_cmu(bp->bp_vend);
208	else if (bcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0)
209		vend_rfc1048(bp->bp_vend, sizeof(bp->bp_vend));
210	else
211		printf("bootprecv: unknown vendor 0x%lx\n", (long)bp->bp_vend);
212
213	/* Check subnet mask against net mask; toss if bogus */
214	if ((nmask & smask) != nmask) {
215#ifdef BOOTP_DEBUG
216		if (debug)
217			printf("subnet mask (%s) bad\n", intoa(smask));
218#endif
219		smask = 0;
220	}
221
222	/* Get subnet (or natural net) mask */
223	netmask = nmask;
224	if (smask)
225		netmask = smask;
226#ifdef BOOTP_DEBUG
227	if (debug)
228		printf("mask: %s\n", intoa(netmask));
229#endif
230
231	/* We need a gateway if root or swap is on a different net */
232	if (!SAMENET(d->myip, rootip, netmask)) {
233#ifdef BOOTP_DEBUG
234		if (debug)
235			printf("need gateway for root ip\n");
236#endif
237	}
238
239	if (!SAMENET(d->myip, swapip, netmask)) {
240#ifdef BOOTP_DEBUG
241		if (debug)
242			printf("need gateway for swap ip\n");
243#endif
244	}
245
246	/* Toss gateway if on a different net */
247	if (!SAMENET(d->myip, gateip, netmask)) {
248#ifdef BOOTP_DEBUG
249		if (debug)
250			printf("gateway ip (%s) bad\n", inet_ntoa(gateip));
251#endif
252		gateip.s_addr = 0;
253	}
254
255	return (n);
256
257bad:
258	errno = 0;
259	return (-1);
260}
261
262static void
263vend_cmu(u_char *cp)
264{
265	struct cmu_vend *vp;
266
267#ifdef BOOTP_DEBUG
268	if (debug)
269		printf("vend_cmu bootp info.\n");
270#endif
271	vp = (struct cmu_vend *)cp;
272
273	if (vp->v_smask.s_addr != 0)
274		smask = vp->v_smask.s_addr;
275	if (vp->v_dgate.s_addr != 0)
276		gateip = vp->v_dgate;
277}
278
279static void
280vend_rfc1048(u_char *cp, u_int len)
281{
282	u_char *ep;
283	int size;
284	u_char tag;
285
286#ifdef BOOTP_DEBUG
287	if (debug)
288		printf("vend_rfc1048 bootp info. len=%d\n", len);
289#endif
290	ep = cp + len;
291
292	/* Step over magic cookie */
293	cp += sizeof(int);
294
295	while (cp < ep) {
296		tag = *cp++;
297		size = *cp++;
298		if (tag == TAG_END)
299			break;
300
301		if (tag == TAG_SUBNET_MASK)
302			bcopy(cp, &smask, sizeof(smask));
303		if (tag == TAG_GATEWAY)
304			bcopy(cp, &gateip.s_addr, sizeof(gateip.s_addr));
305		if (tag == TAG_SWAPSERVER)
306			bcopy(cp, &swapip.s_addr, sizeof(swapip.s_addr));
307		if (tag == TAG_DOMAIN_SERVER)
308			bcopy(cp, &nameip.s_addr, sizeof(nameip.s_addr));
309		if (tag == TAG_ROOTPATH) {
310			strncpy(rootpath, (char *)cp, sizeof(rootpath));
311			rootpath[size] = '\0';
312		}
313		if (tag == TAG_HOSTNAME) {
314			strncpy(hostname, (char *)cp, sizeof(hostname));
315			hostname[size] = '\0';
316		}
317		if (tag == TAG_DOMAINNAME) {
318			strncpy(domainname, (char *)cp, sizeof(domainname));
319			domainname[size] = '\0';
320		}
321		cp += size;
322	}
323}
324