1/*	$NetBSD: nfs_bootdhcp.c,v 1.58 2024/05/13 00:24:19 msaitoh Exp $	*/
2
3/*-
4 * Copyright (c) 1995, 1997 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Adam Glass and Gordon W. Ross.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * Support for NFS diskless booting with BOOTP (RFC951, RFC1048)
34 *
35 * History:
36 *
37 * Tor Egge developed the initial version of this code based on
38 * the Sun RPC/bootparam sources nfs_boot.c and krpc_subr.c and
39 * submitted that work to NetBSD as bugreport "kern/2351" on
40 * 29 Apr 1996.
41 *
42 * Gordon Ross reorganized Tor's version into this form and
43 * integrated it into the NetBSD sources during Aug 1997.
44 */
45
46#include <sys/cdefs.h>
47__KERNEL_RCSID(0, "$NetBSD: nfs_bootdhcp.c,v 1.58 2024/05/13 00:24:19 msaitoh Exp $");
48
49#ifdef _KERNEL_OPT
50#include "opt_nfs_boot.h"
51#include "opt_tftproot.h"
52#endif
53
54#include <sys/param.h>
55#include <sys/systm.h>
56#include <sys/kernel.h>
57#include <sys/device.h>
58#include <sys/ioctl.h>
59#include <sys/proc.h>
60#include <sys/mount.h>
61#include <sys/mbuf.h>
62#include <sys/reboot.h>
63#include <sys/socket.h>
64#include <sys/socketvar.h>
65
66#include <net/if.h>
67#include <net/if_types.h>
68#include <net/if_arp.h> 	/* ARPHRD_ETHER, etc. */
69#include <net/if_dl.h>
70#include <net/if_ether.h>
71#include <net/route.h>
72
73#include <netinet/in.h>
74#include <netinet/if_inarp.h>
75
76#include <nfs/rpcv2.h>
77
78#include <nfs/nfsproto.h>
79#include <nfs/nfs.h>
80#include <nfs/nfsmount.h>
81#include <nfs/nfsdiskless.h>
82
83/*
84 * There are two implementations of NFS diskless boot.
85 * This implementation uses BOOTP (RFC951, RFC1048), and
86 * the other uses Sun RPC/bootparams (nfs_bootparam.c).
87 *
88 * This method gets everything it needs with one BOOTP
89 * request and reply.  Note that this actually uses only
90 * the old BOOTP functionality subset of DHCP.  It is not
91 * clear that DHCP provides any advantage over BOOTP for
92 * diskless boot.  DHCP allows the server to assign an IP
93 * address without any a-priori knowledge of the client,
94 * but we require that the server has a-priori knowledge
95 * of the client so it can export our (unique) NFS root.
96 * Given that the server needs a-priori knowledge about
97 * the client anyway, it might as well assign a fixed IP
98 * address for the client and support BOOTP.
99 *
100 * On the other hand, disk-FULL clients may use DHCP, but
101 * in that case the DHCP client should be user-mode code,
102 * and has no bearing on the code below. -gwr
103 */
104
105/* Begin stuff from bootp.h */
106/* Definitions from RFC951 */
107#define BP_CHADDR_LEN	 16
108#define BP_SNAME_LEN	 64
109#define BP_FILE_LEN	128
110#define BP_VEND_LEN	 64
111struct bootp {
112	u_int8_t	bp_op;		/* packet opcode type */
113	u_int8_t	bp_htype;	/* hardware addr type */
114	u_int8_t	bp_hlen;	/* hardware addr length */
115	u_int8_t	bp_hops;	/* gateway hops */
116	u_int32_t	bp_xid;		/* transaction ID */
117	u_int16_t	bp_secs;	/* seconds since boot began */
118	u_int16_t	bp_flags;	/* RFC1532 broadcast, etc. */
119	struct in_addr	bp_ciaddr;	/* client IP address */
120	struct in_addr	bp_yiaddr;	/* 'your' IP address */
121	struct in_addr	bp_siaddr;	/* server IP address */
122	struct in_addr	bp_giaddr;	/* gateway IP address */
123	u_int8_t bp_chaddr[BP_CHADDR_LEN]; /* client hardware address */
124	char	bp_sname[BP_SNAME_LEN]; /* server host name */
125	char	bp_file[BP_FILE_LEN];	/* boot file name */
126	u_int8_t bp_vend[BP_VEND_LEN];	/* RFC1048 options */
127	/*
128	 * Note that BOOTP packets are allowed to be longer
129	 * (see RFC 1532 sect. 2.1) and common practice is to
130	 * allow the option data in bp_vend to extend into the
131	 * additional space provided in longer packets.
132	 */
133};
134
135#define IPPORT_BOOTPS 67
136#define IPPORT_BOOTPC 68
137
138#define BOOTREQUEST		1
139#define BOOTREPLY		2
140
141/*
142 * Is this available from the sockaddr_dl somehow?
143 * Perhaps (struct arphdr)->ar_hrd = ARPHRD_ETHER?
144 * The interface has ->if_type but not the ARP fmt.
145 */
146#define HTYPE_ETHERNET		1
147#define HTYPE_IEEE802		6
148
149/*
150 * Vendor magic cookie (v_magic) for RFC1048
151 */
152static const u_int8_t vm_rfc1048[4] = { 99, 130, 83, 99 };
153
154/*
155 * Tag values used to specify what information is being supplied in
156 * the vendor (options) data area of the packet.
157 */
158/* RFC 1048 */
159#define TAG_END			((unsigned char) 255)
160#define TAG_PAD			((unsigned char)   0)
161#define TAG_SUBNET_MASK		((unsigned char)   1)
162#define TAG_TIME_OFFSET		((unsigned char)   2)
163#define TAG_GATEWAY		((unsigned char)   3)
164#define TAG_TIME_SERVER		((unsigned char)   4)
165#define TAG_NAME_SERVER		((unsigned char)   5)
166#define TAG_DOMAIN_SERVER	((unsigned char)   6)
167#define TAG_LOG_SERVER		((unsigned char)   7)
168#define TAG_COOKIE_SERVER	((unsigned char)   8)
169#define TAG_LPR_SERVER		((unsigned char)   9)
170#define TAG_IMPRESS_SERVER	((unsigned char)  10)
171#define TAG_RLP_SERVER		((unsigned char)  11)
172#define TAG_HOST_NAME		((unsigned char)  12)
173#define TAG_BOOT_SIZE		((unsigned char)  13)
174/* RFC 1395 */
175#define TAG_DUMP_FILE		((unsigned char)  14)
176#define TAG_DOMAIN_NAME		((unsigned char)  15)
177#define TAG_SWAP_SERVER		((unsigned char)  16)
178#define TAG_ROOT_PATH		((unsigned char)  17)
179/* RFC 2132 */
180#define TAG_INTERFACE_MTU	((unsigned char)  26)
181/* End of stuff from bootp.h */
182
183#ifdef NFS_BOOT_DHCP
184#define TAG_REQ_ADDR		((unsigned char)  50)
185#define TAG_LEASETIME		((unsigned char)  51)
186#define TAG_OVERLOAD		((unsigned char)  52)
187#define TAG_DHCP_MSGTYPE	((unsigned char)  53)
188#define TAG_SERVERID		((unsigned char)  54)
189#define TAG_PARAM_REQ		((unsigned char)  55)
190#define TAG_MSG			((unsigned char)  56)
191#define TAG_MAXSIZE		((unsigned char)  57)
192#define TAG_T1			((unsigned char)  58)
193#define TAG_T2			((unsigned char)  59)
194#define TAG_CLASSID		((unsigned char)  60)
195#define TAG_CLIENTID		((unsigned char)  61)
196#endif
197
198#ifdef NFS_BOOT_DHCP
199#define DHCPDISCOVER 1
200#define DHCPOFFER 2
201#define DHCPREQUEST 3
202#define DHCPDECLINE 4
203#define DHCPACK 5
204#define DHCPNAK 6
205#define DHCPRELEASE 7
206#endif
207
208#define IP_MIN_MTU 576
209
210#ifdef NFS_BOOT_DHCP
211#define BOOTP_SIZE_MAX	(sizeof(struct bootp)+312-64)
212#else
213/*
214 * The "extended" size is somewhat arbitrary, but is
215 * constrained by the maximum message size specified
216 * by RFC1533 (567 total).  This value increases the
217 * space for options from 64 bytes to 256 bytes.
218 */
219#define BOOTP_SIZE_MAX	(sizeof(struct bootp)+256-64)
220#endif
221#define BOOTP_SIZE_MIN	(sizeof(struct bootp))
222
223/* Convenience macro */
224#define INTOHL(ina) ((u_int32_t)ntohl((ina).s_addr))
225
226static int bootpc_call (struct nfs_diskless *, struct lwp *, int *);
227static void bootp_extract (struct bootp *, int, struct nfs_diskless *, int *);
228
229#ifdef	DEBUG_NFS_BOOT_DHCP
230#define DPRINTF(s)  printf s
231#else
232#define DPRINTF(s)
233#endif
234
235
236/*
237 * Get our boot parameters using BOOTP.
238 */
239int
240nfs_bootdhcp(struct nfs_diskless *nd, struct lwp *lwp, int *flags)
241{
242	struct ifnet *ifp = nd->nd_ifp;
243	int error;
244
245	/*
246	 * Do enough of ifconfig(8) so that the chosen interface
247	 * can talk to the servers.  Use address zero for now.
248	 */
249	error = nfs_boot_setaddress(ifp, lwp,
250		*flags & NFS_BOOT_HAS_MYIP ? nd->nd_myip.s_addr : INADDR_ANY,
251		*flags & NFS_BOOT_HAS_MASK ? nd->nd_mask.s_addr : INADDR_ANY,
252		    INADDR_BROADCAST);
253	if (error) {
254		printf("nfs_boot: set ifaddr zero, error=%d\n", error);
255		return (error);
256	}
257
258	/* This function call does the real send/recv work. */
259	error = bootpc_call(nd, lwp, flags);
260
261	/* Get rid of the temporary (zero) IP address. */
262	(void) nfs_boot_deladdress(ifp, lwp, INADDR_ANY);
263
264	/* NOW we can test the error from bootpc_call. */
265	if (error)
266		goto out;
267
268	/*
269	 * Do ifconfig with our real IP address and mask.
270	 */
271	error = nfs_boot_setaddress(ifp, lwp, nd->nd_myip.s_addr,
272				    nd->nd_mask.s_addr, INADDR_ANY);
273	if (error) {
274		printf("nfs_boot: set ifaddr real, error=%d\n", error);
275		goto out;
276	}
277
278	if ((*flags & NFS_BOOT_ALLINFO) != NFS_BOOT_ALLINFO) {
279		printf("nfs_boot: missing options (need IP, netmask, "
280		       "gateway, next-server, root-path)\n");
281		return EADDRNOTAVAIL;
282	}
283
284out:
285	if (error) {
286		(void) nfs_boot_ifupdown(ifp, lwp, 0);
287		nfs_boot_flushrt(ifp);
288	}
289	return (error);
290}
291
292struct bootpcontext {
293	int xid;
294	const u_char *haddr;
295	u_char halen;
296	struct bootp *replybuf;
297	int replylen;
298#ifdef NFS_BOOT_DHCP
299	char expected_dhcpmsgtype, dhcp_ok;
300	struct in_addr dhcp_serverip;
301#endif
302};
303
304static int bootpset (struct mbuf*, void*, int);
305static int bootpcheck (struct mbuf**, void*);
306
307static int
308bootpset(struct mbuf *m, void *context, int waited)
309{
310	struct bootp *bootp;
311
312	/* we know it's contiguous (in 1 mbuf cluster) */
313	bootp = mtod(m, struct bootp*);
314
315	bootp->bp_secs = htons(waited);
316
317	return (0);
318}
319
320static int
321bootpcheck(struct mbuf **mp, void *context)
322{
323	struct bootp *bootp;
324	struct bootpcontext *bpc = context;
325	struct mbuf *m = *mp;
326	u_int tag, len;
327	u_char *p, *limit;
328
329	/*
330	 * Is this a valid reply?
331	 */
332	if (m->m_pkthdr.len < BOOTP_SIZE_MIN) {
333		DPRINTF(("bootpcheck: short packet %d < %zu\n",
334		    m->m_pkthdr.len, BOOTP_SIZE_MIN));
335		return (-1);
336	}
337	if (m->m_pkthdr.len > BOOTP_SIZE_MAX) {
338		DPRINTF(("Bootpcheck: long packet %d > %zu\n",
339		   m->m_pkthdr.len, BOOTP_SIZE_MAX));
340		return (-1);
341	}
342
343	/*
344	 * don't make first checks more expensive than necessary
345	 */
346	if (m->m_len < offsetof(struct bootp, bp_sname)) {
347		m = *mp = m_pullup(m, offsetof(struct bootp, bp_sname));
348		if (m == NULL) {
349			DPRINTF(("bootpcheck: m_pullup failed\n"));
350			return (-1);
351		}
352	}
353	bootp = mtod(m, struct bootp*);
354
355	if (bootp->bp_op != BOOTREPLY) {
356		DPRINTF(("bootpcheck: op %d is not reply\n", bootp->bp_op));
357		return (-1);
358	}
359	if (bootp->bp_hlen != bpc->halen) {
360		DPRINTF(("bootpcheck: hlen %d != %d\n", bootp->bp_hlen,
361		    bpc->halen));
362		return (-1);
363	}
364	if (memcmp(bootp->bp_chaddr, bpc->haddr, bpc->halen)) {
365#ifdef DEBUG_NFS_BOOT_DHCP
366		char *bp_chaddr, *haddr;
367
368		bp_chaddr = malloc(3 * bpc->halen, M_TEMP, M_WAITOK);
369		haddr     = malloc(3 * bpc->halen, M_TEMP, M_WAITOK);
370
371		DPRINTF(("bootpcheck: incorrect hwaddr %s != %s\n",
372		    ether_snprintf(bp_chaddr, 3 * bpc->halen,
373		    bootp->bp_chaddr),
374		    ether_snprintf(haddr, 3 * bpc->halen, bpc->haddr)));
375
376		free(bp_chaddr, M_TEMP);
377		free(haddr, M_TEMP);
378#endif
379		return (-1);
380	}
381	if (bootp->bp_xid != bpc->xid) {
382		DPRINTF(("bootpcheck: xid %d != %d\n", bootp->bp_xid,
383		    bpc->xid));
384		return (-1);
385	}
386
387	/*
388	 * OK, it's worth to look deeper.
389	 * We copy the mbuf into a flat buffer here because
390	 * m_pullup() is a bit limited for this purpose
391	 * (doesn't allocate a cluster if necessary).
392	 */
393	bpc->replylen = m->m_pkthdr.len;
394	m_copydata(m, 0, bpc->replylen, (void *)bpc->replybuf);
395	bootp = bpc->replybuf;
396
397	/*
398	 * Check if the IP address we get looks correct.
399	 * (DHCP servers can send junk to unknown clients.)
400	 * XXX more checks might be needed
401	 */
402	if (bootp->bp_yiaddr.s_addr == INADDR_ANY ||
403	    bootp->bp_yiaddr.s_addr == INADDR_BROADCAST) {
404		printf("nfs_boot: wrong IP addr %s",
405		       inet_ntoa(bootp->bp_yiaddr));
406		goto warn;
407	}
408
409	/*
410	 * Check the vendor data.
411	 */
412	if (memcmp(bootp->bp_vend, vm_rfc1048, 4)) {
413		printf("nfs_boot: reply missing options");
414		goto warn;
415	}
416	p = &bootp->bp_vend[4];
417	limit = ((u_char*)bootp) + bpc->replylen;
418	while (p < limit) {
419		tag = *p++;
420		if (tag == TAG_END)
421			break;
422		if (tag == TAG_PAD)
423			continue;
424		len = *p++;
425		if ((p + len) > limit) {
426			printf("nfs_boot: option %d too long", tag);
427			goto warn;
428		}
429		switch (tag) {
430#ifdef NFS_BOOT_DHCP
431		case TAG_DHCP_MSGTYPE:
432			if (*p != bpc->expected_dhcpmsgtype)
433				return (-1);
434			bpc->dhcp_ok = 1;
435			break;
436		case TAG_SERVERID:
437			memcpy(&bpc->dhcp_serverip.s_addr, p,
438			      sizeof(bpc->dhcp_serverip.s_addr));
439			break;
440#endif
441		default:
442			break;
443		}
444		p += len;
445	}
446	return (0);
447
448warn:
449	printf(" (bad reply from %s)\n", inet_ntoa(bootp->bp_siaddr));
450	return (-1);
451}
452
453static void
454bootp_addvend(u_char *area)
455{
456#ifdef NFS_BOOT_DHCP
457	char vci[64];
458	int vcilen;
459
460	*area++ = TAG_PARAM_REQ;
461	*area++ = 7;
462	*area++ = TAG_SUBNET_MASK;
463	*area++ = TAG_GATEWAY;
464	*area++ = TAG_HOST_NAME;
465	*area++ = TAG_DOMAIN_NAME;
466	*area++ = TAG_ROOT_PATH;
467	*area++ = TAG_SWAP_SERVER;
468	*area++ = TAG_INTERFACE_MTU;
469
470	/* Insert a NetBSD Vendor Class Identifier option. */
471	snprintf(vci, sizeof(vci), "%s:%s:kernel:%s", ostype, MACHINE,
472	    osrelease);
473	vcilen = strlen(vci);
474	*area++ = TAG_CLASSID;
475	*area++ = vcilen;
476	(void)memcpy(area, vci, vcilen);
477	area += vcilen;
478#endif
479	*area = TAG_END;
480}
481
482static int
483bootpc_call(struct nfs_diskless *nd, struct lwp *lwp, int *flags)
484{
485	struct socket *so;
486	struct ifnet *ifp = nd->nd_ifp;
487	static u_int32_t xid = ~0xFF;
488	struct bootp *bootp;	/* request */
489	struct mbuf *m;
490	struct sockaddr_in sin;
491	int error;
492	const u_char *haddr;
493	u_char hafmt, halen;
494	struct bootpcontext bpc;
495	unsigned int index;
496
497	error = socreate(AF_INET, &so, SOCK_DGRAM, 0, lwp, NULL);
498	if (error) {
499		printf("bootp: socreate, error=%d\n", error);
500		return (error);
501	}
502
503	/*
504	 * Initialize to NULL anything that will hold an allocation,
505	 * and free each at the end if not null.
506	 */
507	bpc.replybuf = NULL;
508	m = NULL;
509
510	/* Record our H/W (Ethernet) address. */
511	{	const struct sockaddr_dl *sdl = ifp->if_sadl;
512		switch (sdl->sdl_type) {
513		    case IFT_ISO88025:
514			hafmt = HTYPE_IEEE802;
515			break;
516		    case IFT_ETHER:
517		    case IFT_FDDI:
518			hafmt = HTYPE_ETHERNET;
519			break;
520		    default:
521			printf("bootp: unsupported interface type %d\n",
522			       sdl->sdl_type);
523			error = EINVAL;
524			goto out;
525		}
526		halen = sdl->sdl_alen;
527		haddr = (const unsigned char *)CLLADDR(sdl);
528	}
529
530	/*
531	 * Skip the route table when sending on this socket.
532	 * If this is not done, ip_output finds the loopback
533	 * interface (why?) and then fails because broadcast
534	 * is not supported on that interface...
535	 */
536	{	int32_t opt;
537
538		opt = 1;
539		error = so_setsockopt(NULL, so, SOL_SOCKET, SO_DONTROUTE, &opt,
540		    sizeof(opt));
541	}
542	if (error) {
543		DPRINTF(("bootpc_call: SO_DONTROUTE failed %d\n", error));
544		goto out;
545	}
546
547	/* Enable broadcast. */
548	if ((error = nfs_boot_enbroadcast(so))) {
549		DPRINTF(("bootpc_call: SO_BROADCAST failed %d\n", error));
550		goto out;
551	}
552
553	/*
554	 * Set some TTL so we can boot through routers.
555	 * Real BOOTP forwarding agents don't need this; they obey "bp_hops"
556	 * and set "bp_giaddr", thus rewrite the packet anyway.
557	 * The "helper-address" feature of some popular router vendor seems
558	 * to do simple IP forwarding and drops packets with (ip_ttl == 1).
559	 */
560	{	u_char opt;
561
562		opt = 7;
563		error = so_setsockopt(NULL, so, IPPROTO_IP, IP_MULTICAST_TTL,
564		    &opt, sizeof(opt));
565	}
566	if (error) {
567		DPRINTF(("bootpc_call: IP_MULTICAST_TTL failed %d\n", error));
568		goto out;
569	}
570
571	/* Set the receive timeout for the socket. */
572	if ((error = nfs_boot_setrecvtimo(so))) {
573		DPRINTF(("bootpc_call: SO_RCVTIMEO failed %d\n", error));
574		goto out;
575	}
576
577	/*
578	 * Bind the local endpoint to a bootp client port.
579	 */
580	if ((error = nfs_boot_sobind_ipport(so, IPPORT_BOOTPC, lwp))) {
581		DPRINTF(("bootpc_call: bind failed %d\n", error));
582		goto out;
583	}
584
585	/*
586	 * Setup socket address for the server.
587	 */
588	sin.sin_len = sizeof(sin);
589	sin.sin_family = AF_INET;
590	sin.sin_addr.s_addr = INADDR_BROADCAST;
591	sin.sin_port = htons(IPPORT_BOOTPS);
592
593	/*
594	 * Allocate buffer used for request
595	 */
596	m = m_gethdr(M_WAIT, MT_DATA);
597	m_clget(m, M_WAIT);
598	bootp = mtod(m, struct bootp*);
599	m->m_pkthdr.len = m->m_len = BOOTP_SIZE_MAX;
600	m_reset_rcvif(m);
601
602	/*
603	 * Build the BOOTP request message.
604	 * Note: xid is host order! (opaque to server)
605	 */
606	memset((void *)bootp, 0, BOOTP_SIZE_MAX);
607	bootp->bp_op    = BOOTREQUEST;
608	bootp->bp_htype = hafmt;
609	bootp->bp_hlen  = halen;	/* Hardware address length */
610	bootp->bp_xid = ++xid;
611	memcpy(bootp->bp_chaddr, haddr, halen);
612#ifdef NFS_BOOT_BOOTP_REQFILE
613	strncpy(bootp->bp_file, NFS_BOOT_BOOTP_REQFILE, sizeof(bootp->bp_file));
614#endif
615	/* Fill-in the vendor data. */
616	memcpy(bootp->bp_vend, vm_rfc1048, 4);
617	index = 4;
618#ifdef NFS_BOOT_DHCP
619	bootp->bp_vend[index++] = TAG_DHCP_MSGTYPE;
620	bootp->bp_vend[index++] = 1;
621	bootp->bp_vend[index++] = DHCPDISCOVER;
622#endif
623	bootp_addvend(&bootp->bp_vend[index]);
624
625	bpc.xid = xid;
626	bpc.haddr = haddr;
627	bpc.halen = halen;
628	bpc.replybuf = malloc(BOOTP_SIZE_MAX, M_DEVBUF, M_WAITOK);
629	if (bpc.replybuf == NULL)
630		panic("nfs_boot: malloc reply buf");
631#ifdef NFS_BOOT_DHCP
632	bpc.expected_dhcpmsgtype = DHCPOFFER;
633	bpc.dhcp_ok = 0;
634#endif
635
636	error = nfs_boot_sendrecv(so, &sin, bootpset, m,
637				  bootpcheck, NULL, NULL, &bpc, lwp);
638	if (error)
639		goto out;
640
641#ifdef NFS_BOOT_DHCP
642	if (bpc.dhcp_ok) {
643		u_int32_t leasetime;
644		index = 6;
645		bootp->bp_vend[index++] = DHCPREQUEST;
646		bootp->bp_vend[index++] = TAG_REQ_ADDR;
647		bootp->bp_vend[index++] = 4;
648		memcpy(&bootp->bp_vend[index], &bpc.replybuf->bp_yiaddr, 4);
649		index += 4;
650		bootp->bp_vend[index++] = TAG_SERVERID;
651		bootp->bp_vend[index++] = 4;
652		memcpy(&bootp->bp_vend[index], &bpc.dhcp_serverip.s_addr, 4);
653		index += 4;
654		bootp->bp_vend[index++] = TAG_LEASETIME;
655		bootp->bp_vend[index++] = 4;
656		leasetime = htonl(300);
657		memcpy(&bootp->bp_vend[index], &leasetime, 4);
658		index += 4;
659		bootp_addvend(&bootp->bp_vend[index]);
660
661		bpc.expected_dhcpmsgtype = DHCPACK;
662
663		error = nfs_boot_sendrecv(so, &sin, bootpset, m,
664					  bootpcheck, NULL, NULL, &bpc, lwp);
665		if (error)
666			goto out;
667	}
668#endif
669
670	/*
671	 * bootpcheck() has copied the receive mbuf into
672	 * the buffer at bpc.replybuf.
673	 */
674#ifdef NFS_BOOT_DHCP
675	printf("nfs_boot: %s next-server: %s\n",
676	       (bpc.dhcp_ok ? "DHCP" : "BOOTP"),
677#else
678	printf("nfs_boot: BOOTP next-server: %s\n",
679#endif
680	       inet_ntoa(bpc.replybuf->bp_siaddr));
681
682	bootp_extract(bpc.replybuf, bpc.replylen, nd, flags);
683
684out:
685	if (bpc.replybuf)
686		free(bpc.replybuf, M_DEVBUF);
687	if (m)
688		m_freem(m);
689	soclose(so);
690	return (error);
691}
692
693static void
694bootp_extract(struct bootp *bootp, int replylen,
695		struct nfs_diskless *nd, int *flags)
696{
697	struct sockaddr_in *sin;
698	struct in_addr netmask;
699	struct in_addr gateway;
700	struct in_addr rootserver;
701	char *myname;	/* my hostname */
702	char *mydomain;	/* my domainname */
703	char *rootpath;
704	uint16_t myinterfacemtu;
705	int mynamelen;
706	int mydomainlen;
707	int rootpathlen;
708	int overloaded;
709	u_int tag, len;
710	u_char *p, *limit;
711
712	/* Default these to "unspecified". */
713	netmask.s_addr = 0;
714	gateway.s_addr = 0;
715	mydomain    = myname    = rootpath = NULL;
716	mydomainlen = mynamelen = rootpathlen = 0;
717
718	/* default root server to bootp next-server */
719	rootserver = bootp->bp_siaddr;
720	/* assume that server name field is not overloaded by default */
721	overloaded = 0;
722	/* MTU can't be less than IP_MIN_MTU, set to 0 to indicate unset */
723	myinterfacemtu = 0;
724
725	p = &bootp->bp_vend[4];
726	limit = ((u_char*)bootp) + replylen;
727	while (p < limit) {
728		tag = *p++;
729		if (tag == TAG_END)
730			break;
731		if (tag == TAG_PAD)
732			continue;
733		len = *p++;
734#if 0 /* already done in bootpcheck() */
735		if ((p + len) > limit) {
736			printf("nfs_boot: option %d too long\n", tag);
737			break;
738		}
739#endif
740		switch (tag) {
741		    case TAG_SUBNET_MASK:
742			if (len < 4) {
743				printf("nfs_boot: subnet mask < 4 bytes\n");
744				break;
745			}
746			memcpy(&netmask, p, 4);
747			break;
748		    case TAG_GATEWAY:
749			/* Routers */
750			if (len < 4) {
751				printf("nfs_boot: routers < 4 bytes\n");
752				break;
753			}
754			memcpy(&gateway, p, 4);
755			break;
756		    case TAG_HOST_NAME:
757			if (len >= sizeof(hostname)) {
758				printf("nfs_boot: host name >= %lu bytes\n",
759				       (u_long)sizeof(hostname));
760				break;
761			}
762			myname = p;
763			mynamelen = len;
764			break;
765		    case TAG_DOMAIN_NAME:
766			if (len >= sizeof(domainname)) {
767				printf("nfs_boot: domain name >= %lu bytes\n",
768				       (u_long)sizeof(domainname));
769				break;
770			}
771			mydomain = p;
772			mydomainlen = len;
773			break;
774		    case TAG_ROOT_PATH:
775			/* Leave some room for the server name. */
776			if (len >= (MNAMELEN-10)) {
777				printf("nfs_boot: rootpath >= %d bytes\n",
778				       (MNAMELEN-10));
779				break;
780			}
781			rootpath = p;
782			rootpathlen = len;
783			break;
784		    case TAG_INTERFACE_MTU:
785			if (len != 2) {
786				printf("nfs_boot: interface-mtu len != 2 (%d)",
787					len);
788				break;
789			}
790			memcpy(&myinterfacemtu, p, 2);
791			myinterfacemtu = ntohs(myinterfacemtu);
792			break;
793		    case TAG_SWAP_SERVER:
794			/* override NFS server address */
795			if (len < 4) {
796				printf("nfs_boot: swap server < 4 bytes\n");
797				break;
798			}
799			memcpy(&rootserver, p, 4);
800			break;
801#ifdef NFS_BOOT_DHCP
802		    case TAG_OVERLOAD:
803			if (len > 0 && ((*p & 0x02) != 0))
804				/*
805				 * The server name field in the dhcp packet
806				 * is overloaded and we can't find server
807				 * name there.
808				 */
809				overloaded = 1;
810			break;
811#endif
812		    default:
813			break;
814		}
815		p += len;
816	}
817
818	/*
819	 * Store and print network config info.
820	 */
821	if (myname) {
822		myname[mynamelen] = '\0';
823		strncpy(hostname, myname, sizeof(hostname));
824		hostnamelen = mynamelen;
825		printf("nfs_boot: my_name=%s\n", hostname);
826	}
827	if (mydomain) {
828		mydomain[mydomainlen] = '\0';
829		strncpy(domainname, mydomain, sizeof(domainname));
830		domainnamelen = mydomainlen;
831		printf("nfs_boot: my_domain=%s\n", domainname);
832	}
833	if (!(*flags & NFS_BOOT_HAS_MYIP)) {
834		nd->nd_myip = bootp->bp_yiaddr;
835		printf("nfs_boot: my_addr=%s\n", inet_ntoa(nd->nd_myip));
836		*flags |= NFS_BOOT_HAS_MYIP;
837	}
838	if (!(*flags & NFS_BOOT_HAS_MASK)) {
839		nd->nd_mask = netmask;
840		printf("nfs_boot: my_mask=%s\n", inet_ntoa(nd->nd_mask));
841		*flags |= NFS_BOOT_HAS_MASK;
842	}
843	if (!(*flags & NFS_BOOT_HAS_GWIP)) {
844		nd->nd_gwip = gateway;
845		printf("nfs_boot: gateway=%s\n", inet_ntoa(nd->nd_gwip));
846		*flags |= NFS_BOOT_HAS_GWIP;
847	}
848	if (myinterfacemtu >= IP_MIN_MTU) {
849		nd->nd_mtu = myinterfacemtu;
850		printf("nfs_boot: mtu=%d\n", nd->nd_mtu);
851	}
852
853	/*
854	 * Store the information about our NFS root mount.
855	 * The caller will print it, so be silent here.
856	 */
857	do {
858		struct nfs_dlmount *ndm = &nd->nd_root;
859
860
861		if (!(*flags & NFS_BOOT_HAS_SERVADDR)) {
862			/* Server IP address. */
863			sin = (struct sockaddr_in *) &ndm->ndm_saddr;
864			memset((void *)sin, 0, sizeof(*sin));
865			sin->sin_len = sizeof(*sin);
866			sin->sin_family = AF_INET;
867			sin->sin_addr = rootserver;
868			*flags |= NFS_BOOT_HAS_SERVADDR;
869		}
870
871		if (!(*flags & NFS_BOOT_HAS_SERVER)) {
872			/* Server name. */
873			if (!overloaded && bootp->bp_sname[0] != 0 &&
874			    !memcmp(&rootserver, &bootp->bp_siaddr,
875				  sizeof(struct in_addr)))
876			{
877				/* standard root server, we have the name */
878				strncpy(ndm->ndm_host, bootp->bp_sname,
879					BP_SNAME_LEN-1);
880				*flags |= NFS_BOOT_HAS_SERVER;
881			} else {
882				/* Show the server IP address numerically. */
883				strncpy(ndm->ndm_host, inet_ntoa(rootserver),
884					BP_SNAME_LEN-1);
885				*flags |= NFS_BOOT_HAS_SERVER;
886			}
887		}
888
889		if (!(*flags & NFS_BOOT_HAS_ROOTPATH)) {
890			len = strlen(ndm->ndm_host);
891			if (rootpath &&
892			    len + 1 + rootpathlen + 1 <= sizeof(ndm->ndm_host))
893			{
894				ndm->ndm_host[len++] = ':';
895				strncpy(ndm->ndm_host + len,
896					rootpath, rootpathlen);
897				ndm->ndm_host[len + rootpathlen] = '\0';
898				*flags |= NFS_BOOT_HAS_ROOTPATH;
899			} /* else: upper layer will handle error */
900		}
901	} while(0);
902
903#ifdef TFTPROOT
904#if BP_FILE_LEN > MNAMELEN
905#define BOOTFILELEN MNAMELEN
906#else
907#define BOOTFILELEN BP_FILE_LEN
908#endif
909	strncpy(nd->nd_bootfile, bootp->bp_file, BOOTFILELEN);
910	nd->nd_bootfile[BOOTFILELEN - 1] = '\0';
911#undef BOOTFILELEN
912#endif /* TFTPROOT */
913}
914