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. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * @(#) Header: bootp.c,v 1.4 93/09/11 03:13:51 leres Exp (LBL)
36 */
37
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD: stable/12/stand/libsa/bootp.c 337038 2018-08-01 12:06:39Z tsoome $");
40
41 #include <stddef.h>
42 #include <sys/types.h>
43 #include <sys/limits.h>
44 #include <sys/endian.h>
45 #include <netinet/in.h>
46 #include <netinet/in_systm.h>
47
48 #include <string.h>
49
50 #define BOOTP_DEBUGxx
51 #define SUPPORT_DHCP
52
53 #define DHCP_ENV_NOVENDOR 1 /* do not parse vendor options */
54 #define DHCP_ENV_PXE 10 /* assume pxe vendor options */
55 #define DHCP_ENV_FREEBSD 11 /* assume freebsd vendor options */
56 /* set DHCP_ENV to one of the values above to export dhcp options to kenv */
57 #define DHCP_ENV DHCP_ENV_NO_VENDOR
58
59 #include "stand.h"
60 #include "net.h"
61 #include "netif.h"
62 #include "bootp.h"
63
64
65 struct in_addr servip;
66
67 static time_t bot;
68
69 static char vm_rfc1048[4] = VM_RFC1048;
70 #ifdef BOOTP_VEND_CMU
71 static char vm_cmu[4] = VM_CMU;
72 #endif
73
74 /* Local forwards */
75 static ssize_t bootpsend(struct iodesc *, void *, size_t);
76 static ssize_t bootprecv(struct iodesc *, void **, void **, time_t, void *);
77 static int vend_rfc1048(u_char *, u_int);
78 #ifdef BOOTP_VEND_CMU
79 static void vend_cmu(u_char *);
80 #endif
81
82 #ifdef DHCP_ENV /* export the dhcp response to kenv */
83 struct dhcp_opt;
84 static void setenv_(u_char *cp, u_char *ep, struct dhcp_opt *opts);
85 #else
86 #define setenv_(a, b, c)
87 #endif
88
89 #ifdef SUPPORT_DHCP
90 static char expected_dhcpmsgtype = -1, dhcp_ok;
91 struct in_addr dhcp_serverip;
92 #endif
93 struct bootp *bootp_response;
94 size_t bootp_response_size;
95
96 static void
bootp_fill_request(unsigned char * bp_vend)97 bootp_fill_request(unsigned char *bp_vend)
98 {
99 /*
100 * We are booting from PXE, we want to send the string
101 * 'PXEClient' to the DHCP server so you have the option of
102 * only responding to PXE aware dhcp requests.
103 */
104 bp_vend[0] = TAG_CLASSID;
105 bp_vend[1] = 9;
106 bcopy("PXEClient", &bp_vend[2], 9);
107 bp_vend[11] = TAG_USER_CLASS;
108 /* len of each user class + number of user class */
109 bp_vend[12] = 8;
110 /* len of the first user class */
111 bp_vend[13] = 7;
112 bcopy("FreeBSD", &bp_vend[14], 7);
113 bp_vend[21] = TAG_PARAM_REQ;
114 bp_vend[22] = 7;
115 bp_vend[23] = TAG_ROOTPATH;
116 bp_vend[24] = TAG_HOSTNAME;
117 bp_vend[25] = TAG_SWAPSERVER;
118 bp_vend[26] = TAG_GATEWAY;
119 bp_vend[27] = TAG_SUBNET_MASK;
120 bp_vend[28] = TAG_INTF_MTU;
121 bp_vend[29] = TAG_SERVERID;
122 bp_vend[30] = TAG_END;
123 }
124
125 /* Fetch required bootp infomation */
126 void
bootp(int sock)127 bootp(int sock)
128 {
129 void *pkt;
130 struct iodesc *d;
131 struct bootp *bp;
132 struct {
133 u_char header[HEADER_SIZE];
134 struct bootp wbootp;
135 } wbuf;
136 struct bootp *rbootp;
137
138 #ifdef BOOTP_DEBUG
139 if (debug)
140 printf("bootp: socket=%d\n", sock);
141 #endif
142 if (!bot)
143 bot = getsecs();
144
145 if (!(d = socktodesc(sock))) {
146 printf("bootp: bad socket. %d\n", sock);
147 return;
148 }
149 #ifdef BOOTP_DEBUG
150 if (debug)
151 printf("bootp: d=%lx\n", (long)d);
152 #endif
153
154 bp = &wbuf.wbootp;
155 bzero(bp, sizeof(*bp));
156
157 bp->bp_op = BOOTREQUEST;
158 bp->bp_htype = 1; /* 10Mb Ethernet (48 bits) */
159 bp->bp_hlen = 6;
160 bp->bp_xid = htonl(d->xid);
161 MACPY(d->myea, bp->bp_chaddr);
162 strncpy(bp->bp_file, bootfile, sizeof(bp->bp_file));
163 bcopy(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048));
164 #ifdef SUPPORT_DHCP
165 bp->bp_vend[4] = TAG_DHCP_MSGTYPE;
166 bp->bp_vend[5] = 1;
167 bp->bp_vend[6] = DHCPDISCOVER;
168 bootp_fill_request(&bp->bp_vend[7]);
169
170 #else
171 bp->bp_vend[4] = TAG_END;
172 #endif
173
174 d->myip.s_addr = INADDR_ANY;
175 d->myport = htons(IPPORT_BOOTPC);
176 d->destip.s_addr = INADDR_BROADCAST;
177 d->destport = htons(IPPORT_BOOTPS);
178
179 #ifdef SUPPORT_DHCP
180 expected_dhcpmsgtype = DHCPOFFER;
181 dhcp_ok = 0;
182 #endif
183
184 if(sendrecv(d,
185 bootpsend, bp, sizeof(*bp),
186 bootprecv, &pkt, (void **)&rbootp, NULL) == -1) {
187 printf("bootp: no reply\n");
188 return;
189 }
190
191 #ifdef SUPPORT_DHCP
192 if(dhcp_ok) {
193 uint32_t leasetime;
194 bp->bp_vend[6] = DHCPREQUEST;
195 bp->bp_vend[7] = TAG_REQ_ADDR;
196 bp->bp_vend[8] = 4;
197 bcopy(&rbootp->bp_yiaddr, &bp->bp_vend[9], 4);
198 bp->bp_vend[13] = TAG_SERVERID;
199 bp->bp_vend[14] = 4;
200 bcopy(&dhcp_serverip.s_addr, &bp->bp_vend[15], 4);
201 bp->bp_vend[19] = TAG_LEASETIME;
202 bp->bp_vend[20] = 4;
203 leasetime = htonl(300);
204 bcopy(&leasetime, &bp->bp_vend[21], 4);
205 bootp_fill_request(&bp->bp_vend[25]);
206
207 expected_dhcpmsgtype = DHCPACK;
208
209 free(pkt);
210 if(sendrecv(d,
211 bootpsend, bp, sizeof(*bp),
212 bootprecv, &pkt, (void **)&rbootp, NULL) == -1) {
213 printf("DHCPREQUEST failed\n");
214 return;
215 }
216 }
217 #endif
218
219 myip = d->myip = rbootp->bp_yiaddr;
220 servip = rbootp->bp_siaddr;
221 if (rootip.s_addr == INADDR_ANY)
222 rootip = servip;
223 bcopy(rbootp->bp_file, bootfile, sizeof(bootfile));
224 bootfile[sizeof(bootfile) - 1] = '\0';
225
226 if (!netmask) {
227 if (IN_CLASSA(ntohl(myip.s_addr)))
228 netmask = htonl(IN_CLASSA_NET);
229 else if (IN_CLASSB(ntohl(myip.s_addr)))
230 netmask = htonl(IN_CLASSB_NET);
231 else
232 netmask = htonl(IN_CLASSC_NET);
233 #ifdef BOOTP_DEBUG
234 if (debug)
235 printf("'native netmask' is %s\n", intoa(netmask));
236 #endif
237 }
238
239 #ifdef BOOTP_DEBUG
240 if (debug)
241 printf("mask: %s\n", intoa(netmask));
242 #endif
243
244 /* We need a gateway if root is on a different net */
245 if (!SAMENET(myip, rootip, netmask)) {
246 #ifdef BOOTP_DEBUG
247 if (debug)
248 printf("need gateway for root ip\n");
249 #endif
250 }
251
252 /* Toss gateway if on a different net */
253 if (!SAMENET(myip, gateip, netmask)) {
254 #ifdef BOOTP_DEBUG
255 if (debug)
256 printf("gateway ip (%s) bad\n", inet_ntoa(gateip));
257 #endif
258 gateip.s_addr = 0;
259 }
260
261 /* Bump xid so next request will be unique. */
262 ++d->xid;
263 free(pkt);
264 }
265
266 /* Transmit a bootp request */
267 static ssize_t
bootpsend(struct iodesc * d,void * pkt,size_t len)268 bootpsend(struct iodesc *d, void *pkt, size_t len)
269 {
270 struct bootp *bp;
271
272 #ifdef BOOTP_DEBUG
273 if (debug)
274 printf("bootpsend: d=%lx called.\n", (long)d);
275 #endif
276
277 bp = pkt;
278 bp->bp_secs = htons((u_short)(getsecs() - bot));
279
280 #ifdef BOOTP_DEBUG
281 if (debug)
282 printf("bootpsend: calling sendudp\n");
283 #endif
284
285 return (sendudp(d, pkt, len));
286 }
287
288 static ssize_t
bootprecv(struct iodesc * d,void ** pkt,void ** payload,time_t tleft,void * extra)289 bootprecv(struct iodesc *d, void **pkt, void **payload, time_t tleft,
290 void *extra)
291 {
292 ssize_t n;
293 struct bootp *bp;
294 void *ptr;
295
296 #ifdef BOOTP_DEBUG
297 if (debug)
298 printf("bootp_recvoffer: called\n");
299 #endif
300
301 ptr = NULL;
302 n = readudp(d, &ptr, (void **)&bp, tleft);
303 if (n == -1 || n < sizeof(struct bootp) - BOOTP_VENDSIZE)
304 goto bad;
305
306 #ifdef BOOTP_DEBUG
307 if (debug)
308 printf("bootprecv: checked. bp = %p, n = %zd\n", bp, n);
309 #endif
310 if (bp->bp_xid != htonl(d->xid)) {
311 #ifdef BOOTP_DEBUG
312 if (debug) {
313 printf("bootprecv: expected xid 0x%lx, got 0x%x\n",
314 d->xid, ntohl(bp->bp_xid));
315 }
316 #endif
317 goto bad;
318 }
319
320 #ifdef BOOTP_DEBUG
321 if (debug)
322 printf("bootprecv: got one!\n");
323 #endif
324
325 /* Suck out vendor info */
326 if (bcmp(vm_rfc1048, bp->bp_vend, sizeof(vm_rfc1048)) == 0) {
327 int vsize = n - offsetof(struct bootp, bp_vend);
328 if (vend_rfc1048(bp->bp_vend, vsize) != 0)
329 goto bad;
330
331 /* Save copy of bootp reply or DHCP ACK message */
332 if (bp->bp_op == BOOTREPLY &&
333 ((dhcp_ok == 1 && expected_dhcpmsgtype == DHCPACK) ||
334 dhcp_ok == 0)) {
335 free(bootp_response);
336 bootp_response = malloc(n);
337 if (bootp_response != NULL) {
338 bootp_response_size = n;
339 bcopy(bp, bootp_response, bootp_response_size);
340 }
341 }
342 }
343 #ifdef BOOTP_VEND_CMU
344 else if (bcmp(vm_cmu, bp->bp_vend, sizeof(vm_cmu)) == 0)
345 vend_cmu(bp->bp_vend);
346 #endif
347 else
348 printf("bootprecv: unknown vendor 0x%lx\n", (long)bp->bp_vend);
349
350 *pkt = ptr;
351 *payload = bp;
352 return (n);
353 bad:
354 free(ptr);
355 errno = 0;
356 return (-1);
357 }
358
359 static int
vend_rfc1048(u_char * cp,u_int len)360 vend_rfc1048(u_char *cp, u_int len)
361 {
362 u_char *ep;
363 int size;
364 u_char tag;
365 const char *val;
366
367 #ifdef BOOTP_DEBUG
368 if (debug)
369 printf("vend_rfc1048 bootp info. len=%d\n", len);
370 #endif
371 ep = cp + len;
372
373 /* Step over magic cookie */
374 cp += sizeof(int);
375
376 setenv_(cp, ep, NULL);
377
378 while (cp < ep) {
379 tag = *cp++;
380 size = *cp++;
381 if (tag == TAG_END)
382 break;
383
384 if (tag == TAG_SUBNET_MASK) {
385 bcopy(cp, &netmask, sizeof(netmask));
386 }
387 if (tag == TAG_GATEWAY) {
388 bcopy(cp, &gateip.s_addr, sizeof(gateip.s_addr));
389 }
390 if (tag == TAG_SWAPSERVER) {
391 /* let it override bp_siaddr */
392 bcopy(cp, &rootip.s_addr, sizeof(rootip.s_addr));
393 }
394 if (tag == TAG_ROOTPATH) {
395 if ((val = getenv("dhcp.root-path")) == NULL)
396 val = (const char *)cp;
397 strlcpy(rootpath, val, sizeof(rootpath));
398 }
399 if (tag == TAG_HOSTNAME) {
400 if ((val = getenv("dhcp.host-name")) == NULL)
401 val = (const char *)cp;
402 strlcpy(hostname, val, sizeof(hostname));
403 }
404 if (tag == TAG_INTF_MTU) {
405 intf_mtu = 0;
406 if ((val = getenv("dhcp.interface-mtu")) != NULL) {
407 unsigned long tmp;
408 char *end;
409
410 errno = 0;
411 /*
412 * Do not allow MTU to exceed max IPv4 packet
413 * size, max value of 16-bit word.
414 */
415 tmp = strtoul(val, &end, 0);
416 if (errno != 0 ||
417 *val == '\0' || *end != '\0' ||
418 tmp > USHRT_MAX) {
419 printf("%s: bad value: \"%s\", "
420 "ignoring\n",
421 "dhcp.interface-mtu", val);
422 } else {
423 intf_mtu = (u_int)tmp;
424 }
425 }
426 if (intf_mtu <= 0)
427 intf_mtu = be16dec(cp);
428 }
429 #ifdef SUPPORT_DHCP
430 if (tag == TAG_DHCP_MSGTYPE) {
431 if(*cp != expected_dhcpmsgtype)
432 return(-1);
433 dhcp_ok = 1;
434 }
435 if (tag == TAG_SERVERID) {
436 bcopy(cp, &dhcp_serverip.s_addr,
437 sizeof(dhcp_serverip.s_addr));
438 }
439 #endif
440 cp += size;
441 }
442 return(0);
443 }
444
445 #ifdef BOOTP_VEND_CMU
446 static void
vend_cmu(u_char * cp)447 vend_cmu(u_char *cp)
448 {
449 struct cmu_vend *vp;
450
451 #ifdef BOOTP_DEBUG
452 if (debug)
453 printf("vend_cmu bootp info.\n");
454 #endif
455 vp = (struct cmu_vend *)cp;
456
457 if (vp->v_smask.s_addr != 0) {
458 netmask = vp->v_smask.s_addr;
459 }
460 if (vp->v_dgate.s_addr != 0) {
461 gateip = vp->v_dgate;
462 }
463 }
464 #endif
465
466 #ifdef DHCP_ENV
467 /*
468 * Parse DHCP options and store them into kenv variables.
469 * Original code from Danny Braniss, modifications by Luigi Rizzo.
470 *
471 * The parser is driven by tables which specify the type and name of
472 * each dhcp option and how it appears in kenv.
473 * The first entry in the list contains the prefix used to set the kenv
474 * name (including the . if needed), the last entry must have a 0 tag.
475 * Entries do not need to be sorted though it helps for readability.
476 *
477 * Certain vendor-specific tables can be enabled according to DHCP_ENV.
478 * Set it to 0 if you don't want any.
479 */
480 enum opt_fmt { __NONE = 0,
481 __8 = 1, __16 = 2, __32 = 4, /* Unsigned fields, value=size */
482 __IP, /* IPv4 address */
483 __TXT, /* C string */
484 __BYTES, /* byte sequence, printed %02x */
485 __INDIR, /* name=value */
486 __ILIST, /* name=value;name=value ... */
487 __VE, /* vendor specific, recurse */
488 };
489
490 struct dhcp_opt {
491 uint8_t tag;
492 uint8_t fmt;
493 const char *desc;
494 };
495
496 static struct dhcp_opt vndr_opt[] = { /* Vendor Specific Options */
497 #if DHCP_ENV == DHCP_ENV_FREEBSD /* FreeBSD table in the original code */
498 {0, 0, "FreeBSD"}, /* prefix */
499 {1, __TXT, "kernel"},
500 {2, __TXT, "kernelname"},
501 {3, __TXT, "kernel_options"},
502 {4, __IP, "usr-ip"},
503 {5, __TXT, "conf-path"},
504 {6, __TXT, "rc.conf0"},
505 {7, __TXT, "rc.conf1"},
506 {8, __TXT, "rc.conf2"},
507 {9, __TXT, "rc.conf3"},
508 {10, __TXT, "rc.conf4"},
509 {11, __TXT, "rc.conf5"},
510 {12, __TXT, "rc.conf6"},
511 {13, __TXT, "rc.conf7"},
512 {14, __TXT, "rc.conf8"},
513 {15, __TXT, "rc.conf9"},
514
515 {20, __TXT, "boot.nfsroot.options"},
516
517 {245, __INDIR, ""},
518 {246, __INDIR, ""},
519 {247, __INDIR, ""},
520 {248, __INDIR, ""},
521 {249, __INDIR, ""},
522 {250, __INDIR, ""},
523 {251, __INDIR, ""},
524 {252, __INDIR, ""},
525 {253, __INDIR, ""},
526 {254, __INDIR, ""},
527
528 #elif DHCP_ENV == DHCP_ENV_PXE /* some pxe options, RFC4578 */
529 {0, 0, "pxe"}, /* prefix */
530 {93, __16, "system-architecture"},
531 {94, __BYTES, "network-interface"},
532 {97, __BYTES, "machine-identifier"},
533 #else /* default (empty) table */
534 {0, 0, "dhcp.vendor."}, /* prefix */
535 #endif
536 {0, __TXT, "%soption-%d"}
537 };
538
539 static struct dhcp_opt dhcp_opt[] = {
540 /* DHCP Option names, formats and codes, from RFC2132. */
541 {0, 0, "dhcp."}, // prefix
542 {1, __IP, "subnet-mask"},
543 {2, __32, "time-offset"}, /* this is signed */
544 {3, __IP, "routers"},
545 {4, __IP, "time-servers"},
546 {5, __IP, "ien116-name-servers"},
547 {6, __IP, "domain-name-servers"},
548 {7, __IP, "log-servers"},
549 {8, __IP, "cookie-servers"},
550 {9, __IP, "lpr-servers"},
551 {10, __IP, "impress-servers"},
552 {11, __IP, "resource-location-servers"},
553 {12, __TXT, "host-name"},
554 {13, __16, "boot-size"},
555 {14, __TXT, "merit-dump"},
556 {15, __TXT, "domain-name"},
557 {16, __IP, "swap-server"},
558 {17, __TXT, "root-path"},
559 {18, __TXT, "extensions-path"},
560 {19, __8, "ip-forwarding"},
561 {20, __8, "non-local-source-routing"},
562 {21, __IP, "policy-filter"},
563 {22, __16, "max-dgram-reassembly"},
564 {23, __8, "default-ip-ttl"},
565 {24, __32, "path-mtu-aging-timeout"},
566 {25, __16, "path-mtu-plateau-table"},
567 {26, __16, "interface-mtu"},
568 {27, __8, "all-subnets-local"},
569 {28, __IP, "broadcast-address"},
570 {29, __8, "perform-mask-discovery"},
571 {30, __8, "mask-supplier"},
572 {31, __8, "perform-router-discovery"},
573 {32, __IP, "router-solicitation-address"},
574 {33, __IP, "static-routes"},
575 {34, __8, "trailer-encapsulation"},
576 {35, __32, "arp-cache-timeout"},
577 {36, __8, "ieee802-3-encapsulation"},
578 {37, __8, "default-tcp-ttl"},
579 {38, __32, "tcp-keepalive-interval"},
580 {39, __8, "tcp-keepalive-garbage"},
581 {40, __TXT, "nis-domain"},
582 {41, __IP, "nis-servers"},
583 {42, __IP, "ntp-servers"},
584 {43, __VE, "vendor-encapsulated-options"},
585 {44, __IP, "netbios-name-servers"},
586 {45, __IP, "netbios-dd-server"},
587 {46, __8, "netbios-node-type"},
588 {47, __TXT, "netbios-scope"},
589 {48, __IP, "x-font-servers"},
590 {49, __IP, "x-display-managers"},
591 {50, __IP, "dhcp-requested-address"},
592 {51, __32, "dhcp-lease-time"},
593 {52, __8, "dhcp-option-overload"},
594 {53, __8, "dhcp-message-type"},
595 {54, __IP, "dhcp-server-identifier"},
596 {55, __8, "dhcp-parameter-request-list"},
597 {56, __TXT, "dhcp-message"},
598 {57, __16, "dhcp-max-message-size"},
599 {58, __32, "dhcp-renewal-time"},
600 {59, __32, "dhcp-rebinding-time"},
601 {60, __TXT, "vendor-class-identifier"},
602 {61, __TXT, "dhcp-client-identifier"},
603 {64, __TXT, "nisplus-domain"},
604 {65, __IP, "nisplus-servers"},
605 {66, __TXT, "tftp-server-name"},
606 {67, __TXT, "bootfile-name"},
607 {68, __IP, "mobile-ip-home-agent"},
608 {69, __IP, "smtp-server"},
609 {70, __IP, "pop-server"},
610 {71, __IP, "nntp-server"},
611 {72, __IP, "www-server"},
612 {73, __IP, "finger-server"},
613 {74, __IP, "irc-server"},
614 {75, __IP, "streettalk-server"},
615 {76, __IP, "streettalk-directory-assistance-server"},
616 {77, __TXT, "user-class"},
617 {85, __IP, "nds-servers"},
618 {86, __TXT, "nds-tree-name"},
619 {87, __TXT, "nds-context"},
620 {210, __TXT, "authenticate"},
621
622 /* use the following entries for arbitrary variables */
623 {246, __ILIST, ""},
624 {247, __ILIST, ""},
625 {248, __ILIST, ""},
626 {249, __ILIST, ""},
627 {250, __INDIR, ""},
628 {251, __INDIR, ""},
629 {252, __INDIR, ""},
630 {253, __INDIR, ""},
631 {254, __INDIR, ""},
632 {0, __TXT, "%soption-%d"}
633 };
634
635 /*
636 * parse a dhcp response, set environment variables translating options
637 * names and values according to the tables above. Also set dhcp.tags
638 * to the list of selected tags.
639 */
640 static void
setenv_(u_char * cp,u_char * ep,struct dhcp_opt * opts)641 setenv_(u_char *cp, u_char *ep, struct dhcp_opt *opts)
642 {
643 u_char *ncp;
644 u_char tag;
645 char tags[512], *tp; /* the list of tags */
646
647 #define FLD_SEP ',' /* separator in list of elements */
648 ncp = cp;
649 tp = tags;
650 if (opts == NULL)
651 opts = dhcp_opt;
652
653 while (ncp < ep) {
654 unsigned int size; /* option size */
655 char *vp, *endv, buf[256]; /* the value buffer */
656 struct dhcp_opt *op;
657
658 tag = *ncp++; /* extract tag and size */
659 size = *ncp++;
660 cp = ncp; /* current payload */
661 ncp += size; /* point to the next option */
662
663 if (tag == TAG_END)
664 break;
665 if (tag == 0)
666 continue;
667
668 for (op = opts+1; op->tag && op->tag != tag; op++)
669 ;
670 /* if not found we end up on the default entry */
671
672 /*
673 * Copy data into the buffer. libstand does not have snprintf so we
674 * need to be careful with sprintf(). With strings, the source is
675 * always <256 char so shorter than the buffer so we are safe; with
676 * other arguments, the longest string is inet_ntoa which is 16 bytes
677 * so we make sure to have always enough room in the string before
678 * trying an sprint.
679 */
680 vp = buf;
681 *vp = '\0';
682 endv = buf + sizeof(buf) - 1 - 16; /* last valid write position */
683
684 switch(op->fmt) {
685 case __NONE:
686 break; /* should not happen */
687
688 case __VE: /* recurse, vendor specific */
689 setenv_(cp, cp+size, vndr_opt);
690 break;
691
692 case __IP: /* ip address */
693 for (; size > 0 && vp < endv; size -= 4, cp += 4) {
694 struct in_addr in_ip; /* ip addresses */
695 if (vp != buf)
696 *vp++ = FLD_SEP;
697 bcopy(cp, &in_ip.s_addr, sizeof(in_ip.s_addr));
698 sprintf(vp, "%s", inet_ntoa(in_ip));
699 vp += strlen(vp);
700 }
701 break;
702
703 case __BYTES: /* opaque byte string */
704 for (; size > 0 && vp < endv; size -= 1, cp += 1) {
705 sprintf(vp, "%02x", *cp);
706 vp += strlen(vp);
707 }
708 break;
709
710 case __TXT:
711 bcopy(cp, buf, size); /* cannot overflow */
712 buf[size] = 0;
713 break;
714
715 case __32:
716 case __16:
717 case __8: /* op->fmt is also the length of each field */
718 for (; size > 0 && vp < endv; size -= op->fmt, cp += op->fmt) {
719 uint32_t v;
720 if (op->fmt == __32)
721 v = (cp[0]<<24) + (cp[1]<<16) + (cp[2]<<8) + cp[3];
722 else if (op->fmt == __16)
723 v = (cp[0]<<8) + cp[1];
724 else
725 v = cp[0];
726 if (vp != buf)
727 *vp++ = FLD_SEP;
728 sprintf(vp, "%u", v);
729 vp += strlen(vp);
730 }
731 break;
732
733 case __INDIR: /* name=value */
734 case __ILIST: /* name=value;name=value... */
735 bcopy(cp, buf, size); /* cannot overflow */
736 buf[size] = '\0';
737 for (endv = buf; endv; endv = vp) {
738 char *s = NULL; /* semicolon ? */
739
740 /* skip leading whitespace */
741 while (*endv && strchr(" \t\n\r", *endv))
742 endv++;
743 vp = strchr(endv, '='); /* find name=value separator */
744 if (!vp)
745 break;
746 *vp++ = 0;
747 if (op->fmt == __ILIST && (s = strchr(vp, ';')))
748 *s++ = '\0';
749 setenv(endv, vp, 1);
750 vp = s; /* prepare for next round */
751 }
752 buf[0] = '\0'; /* option already done */
753 }
754
755 if (tp - tags < sizeof(tags) - 5) { /* add tag to the list */
756 if (tp != tags)
757 *tp++ = FLD_SEP;
758 sprintf(tp, "%d", tag);
759 tp += strlen(tp);
760 }
761 if (buf[0]) {
762 char env[128]; /* the string name */
763
764 if (op->tag == 0)
765 sprintf(env, op->desc, opts[0].desc, tag);
766 else
767 sprintf(env, "%s%s", opts[0].desc, op->desc);
768 /*
769 * Do not replace existing values in the environment, so that
770 * locally-obtained values can override server-provided values.
771 */
772 setenv(env, buf, 0);
773 }
774 }
775 if (tp != tags) {
776 char env[128]; /* the string name */
777 sprintf(env, "%stags", opts[0].desc);
778 setenv(env, tags, 1);
779 }
780 }
781 #endif /* additional dhcp */
782