bootp.c revision 38451 
1/*	$NetBSD: bootp.c,v 1.14 1998/02/16 11:10:54 drochner Exp $	*/
2
3/*
4 * Copyright (c) 1992 Regents of the University of California.
5 * All rights reserved.
6 *
7 * This software was developed by the Computer Systems Engineering group
8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9 * contributed to Berkeley.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *	This product includes software developed by the University of
22 *	California, Lawrence Berkeley Laboratory and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * @(#) Header: bootp.c,v 1.4 93/09/11 03:13:51 leres Exp  (LBL)
40 */
41
42#include <sys/types.h>
43#include <netinet/in.h>
44#include <netinet/in_systm.h>
45
46#include <string.h>
47
48#define BOOTP_DEBUGxx
49#define SUPPORT_DHCP
50
51#include "stand.h"
52#include "net.h"
53#include "netif.h"
54#include "bootp.h"
55
56
57struct in_addr servip;
58
59static n_long	nmask, smask;
60
61static time_t	bot;
62
63static	char vm_rfc1048[4] = VM_RFC1048;
64#ifdef BOOTP_VEND_CMU
65static	char vm_cmu[4] = VM_CMU;
66#endif
67
68/* Local forwards */
69static	ssize_t bootpsend(struct iodesc *, void *, size_t);
70static	ssize_t bootprecv(struct iodesc *, void *, size_t, time_t);
71static	int vend_rfc1048(u_char *, u_int);
72#ifdef BOOTP_VEND_CMU
73static	void vend_cmu(u_char *);
74#endif
75
76#ifdef SUPPORT_DHCP
77static char expected_dhcpmsgtype = -1, dhcp_ok;
78struct in_addr dhcp_serverip;
79#endif
80
81/* Fetch required bootp infomation */
82void
83bootp(sock)
84	int sock;
85{
86	struct iodesc *d;
87	register struct bootp *bp;
88	struct {
89		u_char header[HEADER_SIZE];
90		struct bootp wbootp;
91	} wbuf;
92	struct {
93		u_char header[HEADER_SIZE];
94		struct bootp rbootp;
95	} rbuf;
96
97#ifdef BOOTP_DEBUG
98 	if (debug)
99		printf("bootp: socket=%d\n", sock);
100#endif
101	if (!bot)
102		bot = getsecs();
103
104	if (!(d = socktodesc(sock))) {
105		printf("bootp: bad socket. %d\n", sock);
106		return;
107	}
108#ifdef BOOTP_DEBUG
109 	if (debug)
110		printf("bootp: d=%lx\n", (long)d);
111#endif
112
113	bp = &wbuf.wbootp;
114	bzero(bp, sizeof(*bp));
115
116	bp->bp_op = BOOTREQUEST;
117	bp->bp_htype = 1;		/* 10Mb Ethernet (48 bits) */
118	bp->bp_hlen = 6;
119	bp->bp_xid = htonl(d->xid);
120	MACPY(d->myea, bp->bp_chaddr);
121	strncpy(bp->bp_file, bootfile, sizeof(bp->bp_file));
122	bcopy(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048));
123#ifdef SUPPORT_DHCP
124	bp->bp_vend[4] = TAG_DHCP_MSGTYPE;
125	bp->bp_vend[5] = 1;
126	bp->bp_vend[6] = DHCPDISCOVER;
127	bp->bp_vend[7] = TAG_END;
128#else
129	bp->bp_vend[4] = TAG_END;
130#endif
131
132	d->myip.s_addr = INADDR_ANY;
133	d->myport = htons(IPPORT_BOOTPC);
134	d->destip.s_addr = INADDR_BROADCAST;
135	d->destport = htons(IPPORT_BOOTPS);
136
137#ifdef SUPPORT_DHCP
138	expected_dhcpmsgtype = DHCPOFFER;
139	dhcp_ok = 0;
140#endif
141
142	if(sendrecv(d,
143		    bootpsend, bp, sizeof(*bp),
144		    bootprecv, &rbuf.rbootp, sizeof(rbuf.rbootp))
145	   == -1) {
146	    printf("bootp: no reply\n");
147	    return;
148	}
149
150#ifdef SUPPORT_DHCP
151	if(dhcp_ok) {
152		u_int32_t leasetime;
153		bp->bp_vend[6] = DHCPREQUEST;
154		bp->bp_vend[7] = TAG_REQ_ADDR;
155		bp->bp_vend[8] = 4;
156		bcopy(&rbuf.rbootp.bp_yiaddr, &bp->bp_vend[9], 4);
157		bp->bp_vend[13] = TAG_SERVERID;
158		bp->bp_vend[14] = 4;
159		bcopy(&dhcp_serverip.s_addr, &bp->bp_vend[15], 4);
160		bp->bp_vend[19] = TAG_LEASETIME;
161		bp->bp_vend[20] = 4;
162		leasetime = htonl(300);
163		bcopy(&leasetime, &bp->bp_vend[21], 4);
164		bp->bp_vend[25] = TAG_END;
165
166		expected_dhcpmsgtype = DHCPACK;
167
168		if(sendrecv(d,
169			    bootpsend, bp, sizeof(*bp),
170			    bootprecv, &rbuf.rbootp, sizeof(rbuf.rbootp))
171		   == -1) {
172			printf("DHCPREQUEST failed\n");
173			return;
174		}
175	}
176#endif
177
178	myip = d->myip = rbuf.rbootp.bp_yiaddr;
179	servip = rbuf.rbootp.bp_siaddr;
180	if(rootip.s_addr == INADDR_ANY) rootip = servip;
181	bcopy(rbuf.rbootp.bp_file, bootfile, sizeof(bootfile));
182	bootfile[sizeof(bootfile) - 1] = '\0';
183
184	if (IN_CLASSA(myip.s_addr))
185		nmask = htonl(IN_CLASSA_NET);
186	else if (IN_CLASSB(myip.s_addr))
187		nmask = htonl(IN_CLASSB_NET);
188	else
189		nmask = htonl(IN_CLASSC_NET);
190#ifdef BOOTP_DEBUG
191	if (debug)
192		printf("'native netmask' is %s\n", intoa(nmask));
193#endif
194
195	/* Check subnet mask against net mask; toss if bogus */
196	if ((nmask & smask) != nmask) {
197#ifdef BOOTP_DEBUG
198		if (debug)
199			printf("subnet mask (%s) bad\n", intoa(smask));
200#endif
201		smask = 0;
202	}
203
204	/* Get subnet (or natural net) mask */
205	netmask = nmask;
206	if (smask)
207		netmask = smask;
208#ifdef BOOTP_DEBUG
209	if (debug)
210		printf("mask: %s\n", intoa(netmask));
211#endif
212
213	/* We need a gateway if root is on a different net */
214	if (!SAMENET(myip, rootip, netmask)) {
215#ifdef BOOTP_DEBUG
216		if (debug)
217			printf("need gateway for root ip\n");
218#endif
219	}
220
221	/* Toss gateway if on a different net */
222	if (!SAMENET(myip, gateip, netmask)) {
223#ifdef BOOTP_DEBUG
224		if (debug)
225			printf("gateway ip (%s) bad\n", inet_ntoa(gateip));
226#endif
227		gateip.s_addr = 0;
228	}
229
230	/* Bump xid so next request will be unique. */
231	++d->xid;
232}
233
234/* Transmit a bootp request */
235static ssize_t
236bootpsend(d, pkt, len)
237	register struct iodesc *d;
238	register void *pkt;
239	register size_t len;
240{
241	register struct bootp *bp;
242
243#ifdef BOOTP_DEBUG
244	if (debug)
245		printf("bootpsend: d=%lx called.\n", (long)d);
246#endif
247
248	bp = pkt;
249	bp->bp_secs = htons((u_short)(getsecs() - bot));
250
251#ifdef BOOTP_DEBUG
252	if (debug)
253		printf("bootpsend: calling sendudp\n");
254#endif
255
256	return (sendudp(d, pkt, len));
257}
258
259static ssize_t
260bootprecv(d, pkt, len, tleft)
261register struct iodesc *d;
262register void *pkt;
263register size_t len;
264time_t tleft;
265{
266	register ssize_t n;
267	register struct bootp *bp;
268
269#ifdef BOOTP_DEBUGx
270	if (debug)
271		printf("bootp_recvoffer: called\n");
272#endif
273
274	n = readudp(d, pkt, len, tleft);
275	if (n == -1 || n < sizeof(struct bootp) - BOOTP_VENDSIZE)
276		goto bad;
277
278	bp = (struct bootp *)pkt;
279
280#ifdef BOOTP_DEBUG
281	if (debug)
282		printf("bootprecv: checked.  bp = 0x%lx, n = %d\n",
283		    (long)bp, (int)n);
284#endif
285	if (bp->bp_xid != htonl(d->xid)) {
286#ifdef BOOTP_DEBUG
287		if (debug) {
288			printf("bootprecv: expected xid 0x%lx, got 0x%x\n",
289			    d->xid, ntohl(bp->bp_xid));
290		}
291#endif
292		goto bad;
293	}
294
295#ifdef BOOTP_DEBUG
296	if (debug)
297		printf("bootprecv: got one!\n");
298#endif
299
300	/* Suck out vendor info */
301	if (bcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0) {
302		if(vend_rfc1048(bp->bp_vend, sizeof(bp->bp_vend)) != 0)
303		    goto bad;
304	}
305#ifdef BOOTP_VEND_CMU
306	else if (bcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0)
307		vend_cmu(bp->bp_vend);
308#endif
309	else
310		printf("bootprecv: unknown vendor 0x%lx\n", (long)bp->bp_vend);
311
312	return(n);
313bad:
314	errno = 0;
315	return (-1);
316}
317
318static int
319vend_rfc1048(cp, len)
320	register u_char *cp;
321	u_int len;
322{
323	register u_char *ep;
324	register int size;
325	register u_char tag;
326
327#ifdef BOOTP_DEBUG
328	if (debug)
329		printf("vend_rfc1048 bootp info. len=%d\n", len);
330#endif
331	ep = cp + len;
332
333	/* Step over magic cookie */
334	cp += sizeof(int);
335
336	while (cp < ep) {
337		tag = *cp++;
338		size = *cp++;
339		if (tag == TAG_END)
340			break;
341
342		if (tag == TAG_SUBNET_MASK) {
343			bcopy(cp, &smask, sizeof(smask));
344		}
345		if (tag == TAG_GATEWAY) {
346			bcopy(cp, &gateip.s_addr, sizeof(gateip.s_addr));
347		}
348		if (tag == TAG_SWAPSERVER) {
349			/* let it override bp_siaddr */
350			bcopy(cp, &rootip.s_addr, sizeof(swapip.s_addr));
351		}
352		if (tag == TAG_ROOTPATH) {
353			strncpy(rootpath, (char *)cp, sizeof(rootpath));
354			rootpath[size] = '\0';
355		}
356		if (tag == TAG_HOSTNAME) {
357			strncpy(hostname, (char *)cp, sizeof(hostname));
358			hostname[size] = '\0';
359		}
360#ifdef SUPPORT_DHCP
361		if (tag == TAG_DHCP_MSGTYPE) {
362			if(*cp != expected_dhcpmsgtype)
363			    return(-1);
364			dhcp_ok = 1;
365		}
366		if (tag == TAG_SERVERID) {
367			bcopy(cp, &dhcp_serverip.s_addr,
368			      sizeof(dhcp_serverip.s_addr));
369		}
370#endif
371		cp += size;
372	}
373	return(0);
374}
375
376#ifdef BOOTP_VEND_CMU
377static void
378vend_cmu(cp)
379	u_char *cp;
380{
381	register struct cmu_vend *vp;
382
383#ifdef BOOTP_DEBUG
384	if (debug)
385		printf("vend_cmu bootp info.\n");
386#endif
387	vp = (struct cmu_vend *)cp;
388
389	if (vp->v_smask.s_addr != 0) {
390		smask = vp->v_smask.s_addr;
391	}
392	if (vp->v_dgate.s_addr != 0) {
393		gateip = vp->v_dgate;
394	}
395}
396#endif
397