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      1 /*	$NetBSD: nfs_bootdhcp.c,v 1.60 2024/10/20 14:01:52 mlelstv 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 1.60 2024/10/20 14:01:52 mlelstv 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
    111 struct 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  */
    152 static 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 
    226 static int bootpc_call (struct nfs_diskless *, struct lwp *, int *);
    227 static 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  */
    239 int
    240 nfs_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 
    284 out:
    285 	if (error) {
    286 		(void) nfs_boot_ifupdown(ifp, lwp, 0);
    287 		nfs_boot_flushrt(ifp);
    288 	}
    289 	return (error);
    290 }
    291 
    292 struct 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 
    304 static int bootpset (struct mbuf*, void*, int);
    305 static int bootpcheck (struct mbuf**, void*);
    306 
    307 static int
    308 bootpset(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 
    320 static int
    321 bootpcheck(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 
    448 warn:
    449 	printf(" (bad reply from %s)\n", inet_ntoa(bootp->bp_siaddr));
    450 	return (-1);
    451 }
    452 
    453 static void
    454 bootp_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 
    482 static int
    483 bootpc_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 	MCLAIM(m, &nfs_mowner);
    598 	m_clget(m, M_WAIT);
    599 	bootp = mtod(m, struct bootp*);
    600 	m->m_pkthdr.len = m->m_len = BOOTP_SIZE_MAX;
    601 	m_reset_rcvif(m);
    602 
    603 	/*
    604 	 * Build the BOOTP request message.
    605 	 * Note: xid is host order! (opaque to server)
    606 	 */
    607 	memset((void *)bootp, 0, BOOTP_SIZE_MAX);
    608 	bootp->bp_op    = BOOTREQUEST;
    609 	bootp->bp_htype = hafmt;
    610 	bootp->bp_hlen  = halen;	/* Hardware address length */
    611 	bootp->bp_xid = ++xid;
    612 	memcpy(bootp->bp_chaddr, haddr, halen);
    613 #ifdef NFS_BOOT_BOOTP_REQFILE
    614 	strncpy(bootp->bp_file, NFS_BOOT_BOOTP_REQFILE, sizeof(bootp->bp_file));
    615 #endif
    616 	/* Fill-in the vendor data. */
    617 	memcpy(bootp->bp_vend, vm_rfc1048, 4);
    618 	index = 4;
    619 #ifdef NFS_BOOT_DHCP
    620 	bootp->bp_vend[index++] = TAG_DHCP_MSGTYPE;
    621 	bootp->bp_vend[index++] = 1;
    622 	bootp->bp_vend[index++] = DHCPDISCOVER;
    623 #endif
    624 	bootp_addvend(&bootp->bp_vend[index]);
    625 
    626 	bpc.xid = xid;
    627 	bpc.haddr = haddr;
    628 	bpc.halen = halen;
    629 	bpc.replybuf = malloc(BOOTP_SIZE_MAX, M_DEVBUF, M_WAITOK);
    630 	if (bpc.replybuf == NULL)
    631 		panic("nfs_boot: malloc reply buf");
    632 #ifdef NFS_BOOT_DHCP
    633 	bpc.expected_dhcpmsgtype = DHCPOFFER;
    634 	bpc.dhcp_ok = 0;
    635 #endif
    636 
    637 	error = nfs_boot_sendrecv(so, &sin, bootpset, m,
    638 				  bootpcheck, NULL, NULL, &bpc, lwp);
    639 	if (error)
    640 		goto out;
    641 
    642 #ifdef NFS_BOOT_DHCP
    643 	if (bpc.dhcp_ok) {
    644 		u_int32_t leasetime;
    645 		index = 6;
    646 		bootp->bp_vend[index++] = DHCPREQUEST;
    647 		bootp->bp_vend[index++] = TAG_REQ_ADDR;
    648 		bootp->bp_vend[index++] = 4;
    649 		memcpy(&bootp->bp_vend[index], &bpc.replybuf->bp_yiaddr, 4);
    650 		index += 4;
    651 		bootp->bp_vend[index++] = TAG_SERVERID;
    652 		bootp->bp_vend[index++] = 4;
    653 		memcpy(&bootp->bp_vend[index], &bpc.dhcp_serverip.s_addr, 4);
    654 		index += 4;
    655 		bootp->bp_vend[index++] = TAG_LEASETIME;
    656 		bootp->bp_vend[index++] = 4;
    657 		leasetime = htonl(300);
    658 		memcpy(&bootp->bp_vend[index], &leasetime, 4);
    659 		index += 4;
    660 		bootp_addvend(&bootp->bp_vend[index]);
    661 
    662 		bpc.expected_dhcpmsgtype = DHCPACK;
    663 
    664 		error = nfs_boot_sendrecv(so, &sin, bootpset, m,
    665 					  bootpcheck, NULL, NULL, &bpc, lwp);
    666 		if (error)
    667 			goto out;
    668 	}
    669 #endif
    670 
    671 	/*
    672 	 * bootpcheck() has copied the receive mbuf into
    673 	 * the buffer at bpc.replybuf.
    674 	 */
    675 #ifdef NFS_BOOT_DHCP
    676 	printf("nfs_boot: %s next-server: %s\n",
    677 	       (bpc.dhcp_ok ? "DHCP" : "BOOTP"),
    678 #else
    679 	printf("nfs_boot: BOOTP next-server: %s\n",
    680 #endif
    681 	       inet_ntoa(bpc.replybuf->bp_siaddr));
    682 
    683 	bootp_extract(bpc.replybuf, bpc.replylen, nd, flags);
    684 
    685 out:
    686 	if (bpc.replybuf)
    687 		free(bpc.replybuf, M_DEVBUF);
    688 	m_freem(m);
    689 	soclose(so);
    690 	return (error);
    691 }
    692 
    693 static void
    694 bootp_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