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Import dhcpcd-10.0.2 with the following changes:
[dragonfly.git] / contrib / dhcpcd / src / dhcp.c
blobedd1c011bb08f8954b2bc569692db19fa658d652
1 /* SPDX-License-Identifier: BSD-2-Clause */
2 /*
3 * dhcpcd - DHCP client daemon
4 * Copyright (c) 2006-2023 Roy Marples <roy@marples.name>
5 * All rights reserved
6
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/socket.h>
31
32 #include <arpa/inet.h>
33 #include <net/if.h>
34 #include <net/route.h>
35 #include <netinet/if_ether.h>
36 #include <netinet/in_systm.h>
37 #include <netinet/in.h>
38 #include <netinet/ip.h>
39 #define __FAVOR_BSD /* Nasty glibc hack so we can use BSD semantics for UDP */
40 #include <netinet/udp.h>
41 #undef __FAVOR_BSD
42
43 #ifdef AF_LINK
44 # include <net/if_dl.h>
45 #endif
46
47 #include <assert.h>
48 #include <ctype.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <inttypes.h>
52 #include <stdbool.h>
53 #include <stddef.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58 #include <syslog.h>
59
60 #define ELOOP_QUEUE ELOOP_DHCP
61 #include "config.h"
62 #include "arp.h"
63 #include "bpf.h"
64 #include "common.h"
65 #include "dhcp.h"
66 #include "dhcpcd.h"
67 #include "dhcp-common.h"
68 #include "duid.h"
69 #include "eloop.h"
70 #include "if.h"
71 #include "ipv4.h"
72 #include "ipv4ll.h"
73 #include "logerr.h"
74 #include "privsep.h"
75 #include "sa.h"
76 #include "script.h"
77
78 #define DAD "Duplicate address detected"
79 #define DHCP_MIN_LEASE 20
80
81 #define IPV4A ADDRIPV4 | ARRAY
82 #define IPV4R ADDRIPV4 | REQUEST
83
84 /* We should define a maximum for the NAK exponential backoff */
85 #define NAKOFF_MAX 60
86
87 #ifndef IPDEFTTL
88 #define IPDEFTTL 64 /* RFC1340 */
89 #endif
90
91 /* Support older systems with different defines */
92 #if !defined(IP_RECVPKTINFO) && defined(IP_PKTINFO)
93 #define IP_RECVPKTINFO IP_PKTINFO
94 #endif
95
96 /* Assert the correct structure size for on wire */
97 __CTASSERT(sizeof(struct ip) == 20);
98 __CTASSERT(sizeof(struct udphdr) == 8);
99 __CTASSERT(sizeof(struct bootp) == 300);
100
101 struct dhcp_op {
102 uint8_t value;
103 const char *name;
104 };
105
106 static const struct dhcp_op dhcp_ops[] = {
107 { DHCP_DISCOVER, "DISCOVER" },
108 { DHCP_OFFER, "OFFER" },
109 { DHCP_REQUEST, "REQUEST" },
110 { DHCP_DECLINE, "DECLINE" },
111 { DHCP_ACK, "ACK" },
112 { DHCP_NAK, "NAK" },
113 { DHCP_RELEASE, "RELEASE" },
114 { DHCP_INFORM, "INFORM" },
115 { DHCP_FORCERENEW, "FORCERENEW"},
116 { 0, NULL }
117 };
118
119 static const char * const dhcp_params[] = {
120 "ip_address",
121 "subnet_cidr",
122 "network_number",
123 "filename",
124 "server_name",
125 NULL
126 };
127
128 static int dhcp_openbpf(struct interface *);
129 static void dhcp_start1(void *);
130 #if defined(ARP) && (!defined(KERNEL_RFC5227) || defined(ARPING))
131 static void dhcp_arp_found(struct arp_state *, const struct arp_msg *);
132 #endif
133 static void dhcp_handledhcp(struct interface *, struct bootp *, size_t,
134 const struct in_addr *);
135 static void dhcp_handleifudp(void *, unsigned short);
136 static int dhcp_initstate(struct interface *);
137
138 void
139 dhcp_printoptions(const struct dhcpcd_ctx *ctx,
140 const struct dhcp_opt *opts, size_t opts_len)
141 {
142 const char * const *p;
143 size_t i, j;
144 const struct dhcp_opt *opt, *opt2;
145 int cols;
146
147 for (p = dhcp_params; *p; p++)
148 printf(" %s\n", *p);
149
150 for (i = 0, opt = ctx->dhcp_opts; i < ctx->dhcp_opts_len; i++, opt++) {
151 for (j = 0, opt2 = opts; j < opts_len; j++, opt2++)
152 if (opt->option == opt2->option)
153 break;
154 if (j == opts_len) {
155 cols = printf("%03d %s", opt->option, opt->var);
156 dhcp_print_option_encoding(opt, cols);
157 }
158 }
159 for (i = 0, opt = opts; i < opts_len; i++, opt++) {
160 cols = printf("%03d %s", opt->option, opt->var);
161 dhcp_print_option_encoding(opt, cols);
162 }
163 }
164
165 static const uint8_t *
166 get_option(struct dhcpcd_ctx *ctx,
167 const struct bootp *bootp, size_t bootp_len,
168 unsigned int opt, size_t *opt_len)
169 {
170 const uint8_t *p, *e;
171 uint8_t l, o, ol, overl, *bp;
172 const uint8_t *op;
173 size_t bl;
174
175 if (bootp == NULL || bootp_len < DHCP_MIN_LEN) {
176 errno = EINVAL;
177 return NULL;
178 }
179
180 /* Check we have the magic cookie */
181 if (!IS_DHCP(bootp)) {
182 errno = ENOTSUP;
183 return NULL;
184 }
185
186 p = bootp->vend + 4; /* options after the 4 byte cookie */
187 e = (const uint8_t *)bootp + bootp_len;
188 ol = o = overl = 0;
189 bp = NULL;
190 op = NULL;
191 bl = 0;
192 while (p < e) {
193 o = *p++;
194 switch (o) {
195 case DHO_PAD:
196 /* No length to read */
197 continue;
198 case DHO_END:
199 if (overl & 1) {
200 /* bit 1 set means parse boot file */
201 overl = (uint8_t)(overl & ~1);
202 p = bootp->file;
203 e = p + sizeof(bootp->file);
204 } else if (overl & 2) {
205 /* bit 2 set means parse server name */
206 overl = (uint8_t)(overl & ~2);
207 p = bootp->sname;
208 e = p + sizeof(bootp->sname);
209 } else
210 goto exit;
211 /* No length to read */
212 continue;
213 }
214
215 /* Check we can read the length */
216 if (p == e) {
217 errno = EINVAL;
218 return NULL;
219 }
220 l = *p++;
221
222 /* Check we can read the option data, if present */
223 if (p + l > e) {
224 errno = EINVAL;
225 return NULL;
226 }
227
228 if (o == DHO_OPTSOVERLOADED) {
229 /* Ensure we only get this option once by setting
230 * the last bit as well as the value.
231 * This is valid because only the first two bits
232 * actually mean anything in RFC2132 Section 9.3 */
233 if (l == 1 && !overl)
234 overl = 0x80 | p[0];
235 }
236
237 if (o == opt) {
238 if (op) {
239 /* We must concatonate the options. */
240 if (bl + l > ctx->opt_buffer_len) {
241 size_t pos;
242 uint8_t *nb;
243
244 if (bp)
245 pos = (size_t)
246 (bp - ctx->opt_buffer);
247 else
248 pos = 0;
249 nb = realloc(ctx->opt_buffer, bl + l);
250 if (nb == NULL)
251 return NULL;
252 ctx->opt_buffer = nb;
253 ctx->opt_buffer_len = bl + l;
254 bp = ctx->opt_buffer + pos;
255 }
256 if (bp == NULL)
257 bp = ctx->opt_buffer;
258 memcpy(bp, op, ol);
259 bp += ol;
260 }
261 ol = l;
262 op = p;
263 bl += ol;
264 }
265 p += l;
266 }
267
268 exit:
269 if (opt_len)
270 *opt_len = bl;
271 if (bp) {
272 memcpy(bp, op, ol);
273 return (const uint8_t *)ctx->opt_buffer;
274 }
275 if (op)
276 return op;
277 errno = ENOENT;
278 return NULL;
279 }
280
281 static int
282 get_option_addr(struct dhcpcd_ctx *ctx,
283 struct in_addr *a, const struct bootp *bootp, size_t bootp_len,
284 uint8_t option)
285 {
286 const uint8_t *p;
287 size_t len;
288
289 p = get_option(ctx, bootp, bootp_len, option, &len);
290 if (!p || len < (ssize_t)sizeof(a->s_addr))
291 return -1;
292 memcpy(&a->s_addr, p, sizeof(a->s_addr));
293 return 0;
294 }
295
296 static int
297 get_option_uint32(struct dhcpcd_ctx *ctx,
298 uint32_t *i, const struct bootp *bootp, size_t bootp_len, uint8_t option)
299 {
300 const uint8_t *p;
301 size_t len;
302 uint32_t d;
303
304 p = get_option(ctx, bootp, bootp_len, option, &len);
305 if (!p || len < (ssize_t)sizeof(d))
306 return -1;
307 memcpy(&d, p, sizeof(d));
308 if (i)
309 *i = ntohl(d);
310 return 0;
311 }
312
313 static int
314 get_option_uint16(struct dhcpcd_ctx *ctx,
315 uint16_t *i, const struct bootp *bootp, size_t bootp_len, uint8_t option)
316 {
317 const uint8_t *p;
318 size_t len;
319 uint16_t d;
320
321 p = get_option(ctx, bootp, bootp_len, option, &len);
322 if (!p || len < (ssize_t)sizeof(d))
323 return -1;
324 memcpy(&d, p, sizeof(d));
325 if (i)
326 *i = ntohs(d);
327 return 0;
328 }
329
330 static int
331 get_option_uint8(struct dhcpcd_ctx *ctx,
332 uint8_t *i, const struct bootp *bootp, size_t bootp_len, uint8_t option)
333 {
334 const uint8_t *p;
335 size_t len;
336
337 p = get_option(ctx, bootp, bootp_len, option, &len);
338 if (!p || len < (ssize_t)sizeof(*p))
339 return -1;
340 if (i)
341 *i = *(p);
342 return 0;
343 }
344
345 ssize_t
346 print_rfc3442(FILE *fp, const uint8_t *data, size_t data_len)
347 {
348 const uint8_t *p = data, *e;
349 size_t ocets;
350 uint8_t cidr;
351 struct in_addr addr;
352
353 /* Minimum is 5 -first is CIDR and a router length of 4 */
354 if (data_len < 5) {
355 errno = EINVAL;
356 return -1;
357 }
358
359 e = p + data_len;
360 while (p < e) {
361 if (p != data) {
362 if (fputc(' ', fp) == EOF)
363 return -1;
364 }
365 cidr = *p++;
366 if (cidr > 32) {
367 errno = EINVAL;
368 return -1;
369 }
370 ocets = (size_t)(cidr + 7) / NBBY;
371 if (p + 4 + ocets > e) {
372 errno = ERANGE;
373 return -1;
374 }
375 /* If we have ocets then we have a destination and netmask */
376 addr.s_addr = 0;
377 if (ocets > 0) {
378 memcpy(&addr.s_addr, p, ocets);
379 p += ocets;
380 }
381 if (fprintf(fp, "%s/%d", inet_ntoa(addr), cidr) == -1)
382 return -1;
383
384 /* Finally, snag the router */
385 memcpy(&addr.s_addr, p, 4);
386 p += 4;
387 if (fprintf(fp, " %s", inet_ntoa(addr)) == -1)
388 return -1;
389 }
390
391 if (fputc('\0', fp) == EOF)
392 return -1;
393 return 1;
394 }
395
396 static int
397 decode_rfc3442_rt(rb_tree_t *routes, struct interface *ifp,
398 const uint8_t *data, size_t dl)
399 {
400 const uint8_t *p = data;
401 const uint8_t *e;
402 uint8_t cidr;
403 size_t ocets;
404 struct rt *rt = NULL;
405 struct in_addr dest, netmask, gateway;
406 int n;
407
408 /* Minimum is 5 -first is CIDR and a router length of 4 */
409 if (dl < 5) {
410 errno = EINVAL;
411 return -1;
412 }
413
414 n = 0;
415 e = p + dl;
416 while (p < e) {
417 cidr = *p++;
418 if (cidr > 32) {
419 errno = EINVAL;
420 return -1;
421 }
422
423 ocets = (size_t)(cidr + 7) / NBBY;
424 if (p + 4 + ocets > e) {
425 errno = ERANGE;
426 return -1;
427 }
428
429 if ((rt = rt_new(ifp)) == NULL)
430 return -1;
431
432 /* If we have ocets then we have a destination and netmask */
433 dest.s_addr = 0;
434 if (ocets > 0) {
435 memcpy(&dest.s_addr, p, ocets);
436 p += ocets;
437 netmask.s_addr = htonl(~0U << (32 - cidr));
438 } else
439 netmask.s_addr = 0;
440
441 /* Finally, snag the router */
442 memcpy(&gateway.s_addr, p, 4);
443 p += 4;
444
445 if (netmask.s_addr == INADDR_BROADCAST)
446 rt->rt_flags = RTF_HOST;
447
448 sa_in_init(&rt->rt_dest, &dest);
449 sa_in_init(&rt->rt_netmask, &netmask);
450 sa_in_init(&rt->rt_gateway, &gateway);
451 if (rt_proto_add(routes, rt))
452 n = 1;
453 }
454 return n;
455 }
456
457 ssize_t
458 print_rfc3361(FILE *fp, const uint8_t *data, size_t dl)
459 {
460 uint8_t enc;
461 char sip[NS_MAXDNAME];
462 struct in_addr addr;
463
464 if (dl < 2) {
465 errno = EINVAL;
466 return 0;
467 }
468
469 enc = *data++;
470 dl--;
471 switch (enc) {
472 case 0:
473 if (decode_rfc1035(sip, sizeof(sip), data, dl) == -1)
474 return -1;
475 if (efprintf(fp, "%s", sip) == -1)
476 return -1;
477 break;
478 case 1:
479 if (dl % 4 != 0) {
480 errno = EINVAL;
481 break;
482 }
483 addr.s_addr = INADDR_BROADCAST;
484 for (;
485 dl != 0;
486 data += sizeof(addr.s_addr), dl -= sizeof(addr.s_addr))
487 {
488 memcpy(&addr.s_addr, data, sizeof(addr.s_addr));
489 if (fprintf(fp, "%s", inet_ntoa(addr)) == -1)
490 return -1;
491 if (dl != sizeof(addr.s_addr)) {
492 if (fputc(' ', fp) == EOF)
493 return -1;
494 }
495 }
496 if (fputc('\0', fp) == EOF)
497 return -1;
498 break;
499 default:
500 errno = EINVAL;
501 return 0;
502 }
503
504 return 1;
505 }
506
507 static char *
508 get_option_string(struct dhcpcd_ctx *ctx,
509 const struct bootp *bootp, size_t bootp_len, uint8_t option)
510 {
511 size_t len;
512 const uint8_t *p;
513 char *s;
514
515 p = get_option(ctx, bootp, bootp_len, option, &len);
516 if (!p || len == 0 || *p == '\0')
517 return NULL;
518
519 s = malloc(sizeof(char) * (len + 1));
520 if (s) {
521 memcpy(s, p, len);
522 s[len] = '\0';
523 }
524 return s;
525 }
526
527 /* This calculates the netmask that we should use for static routes.
528 * This IS different from the calculation used to calculate the netmask
529 * for an interface address. */
530 static uint32_t
531 route_netmask(uint32_t ip_in)
532 {
533 /* used to be unsigned long - check if error */
534 uint32_t p = ntohl(ip_in);
535 uint32_t t;
536
537 if (IN_CLASSA(p))
538 t = ~IN_CLASSA_NET;
539 else {
540 if (IN_CLASSB(p))
541 t = ~IN_CLASSB_NET;
542 else {
543 if (IN_CLASSC(p))
544 t = ~IN_CLASSC_NET;
545 else
546 t = 0;
547 }
548 }
549
550 while (t & p)
551 t >>= 1;
552
553 return (htonl(~t));
554 }
555
556 /* We need to obey routing options.
557 * If we have a CSR then we only use that.
558 * Otherwise we add static routes and then routers. */
559 static int
560 get_option_routes(rb_tree_t *routes, struct interface *ifp,
561 const struct bootp *bootp, size_t bootp_len)
562 {
563 struct if_options *ifo = ifp->options;
564 const uint8_t *p;
565 const uint8_t *e;
566 struct rt *rt = NULL;
567 struct in_addr dest, netmask, gateway;
568 size_t len;
569 const char *csr = "";
570 int n;
571
572 /* If we have CSR's then we MUST use these only */
573 if (!has_option_mask(ifo->nomask, DHO_CSR))
574 p = get_option(ifp->ctx, bootp, bootp_len, DHO_CSR, &len);
575 else
576 p = NULL;
577 /* Check for crappy MS option */
578 if (!p && !has_option_mask(ifo->nomask, DHO_MSCSR)) {
579 p = get_option(ifp->ctx, bootp, bootp_len, DHO_MSCSR, &len);
580 if (p)
581 csr = "MS ";
582 }
583 if (p && (n = decode_rfc3442_rt(routes, ifp, p, len)) != -1) {
584 const struct dhcp_state *state;
585
586 state = D_CSTATE(ifp);
587 if (!(ifo->options & DHCPCD_CSR_WARNED) &&
588 !(state->added & STATE_FAKE))
589 {
590 logdebugx("%s: using %sClassless Static Routes",
591 ifp->name, csr);
592 ifo->options |= DHCPCD_CSR_WARNED;
593 }
594 return n;
595 }
596
597 n = 0;
598 /* OK, get our static routes first. */
599 if (!has_option_mask(ifo->nomask, DHO_STATICROUTE))
600 p = get_option(ifp->ctx, bootp, bootp_len,
601 DHO_STATICROUTE, &len);
602 else
603 p = NULL;
604 /* RFC 2131 Section 5.8 states length MUST be in multiples of 8 */
605 if (p && len % 8 == 0) {
606 e = p + len;
607 while (p < e) {
608 memcpy(&dest.s_addr, p, sizeof(dest.s_addr));
609 p += 4;
610 memcpy(&gateway.s_addr, p, sizeof(gateway.s_addr));
611 p += 4;
612 /* RFC 2131 Section 5.8 states default route is
613 * illegal */
614 if (gateway.s_addr == INADDR_ANY)
615 continue;
616 if ((rt = rt_new(ifp)) == NULL)
617 return -1;
618
619 /* A on-link host route is normally set by having the
620 * gateway match the destination or assigned address */
621 if (gateway.s_addr == dest.s_addr ||
622 (gateway.s_addr == bootp->yiaddr ||
623 gateway.s_addr == bootp->ciaddr))
624 {
625 gateway.s_addr = INADDR_ANY;
626 netmask.s_addr = INADDR_BROADCAST;
627 } else
628 netmask.s_addr = route_netmask(dest.s_addr);
629 if (netmask.s_addr == INADDR_BROADCAST)
630 rt->rt_flags = RTF_HOST;
631
632 sa_in_init(&rt->rt_dest, &dest);
633 sa_in_init(&rt->rt_netmask, &netmask);
634 sa_in_init(&rt->rt_gateway, &gateway);
635 if (rt_proto_add(routes, rt))
636 n++;
637 }
638 }
639
640 /* Now grab our routers */
641 if (!has_option_mask(ifo->nomask, DHO_ROUTER))
642 p = get_option(ifp->ctx, bootp, bootp_len, DHO_ROUTER, &len);
643 else
644 p = NULL;
645 if (p && len % 4 == 0) {
646 e = p + len;
647 dest.s_addr = INADDR_ANY;
648 netmask.s_addr = INADDR_ANY;
649 while (p < e) {
650 if ((rt = rt_new(ifp)) == NULL)
651 return -1;
652 memcpy(&gateway.s_addr, p, sizeof(gateway.s_addr));
653 p += 4;
654 sa_in_init(&rt->rt_dest, &dest);
655 sa_in_init(&rt->rt_netmask, &netmask);
656 sa_in_init(&rt->rt_gateway, &gateway);
657 if (rt_proto_add(routes, rt))
658 n++;
659 }
660 }
661
662 return n;
663 }
664
665 uint16_t
666 dhcp_get_mtu(const struct interface *ifp)
667 {
668 const struct dhcp_state *state;
669 uint16_t mtu;
670
671 if (ifp->options->mtu)
672 return (uint16_t)ifp->options->mtu;
673 mtu = 0; /* bogus gcc warning */
674 if ((state = D_CSTATE(ifp)) == NULL ||
675 has_option_mask(ifp->options->nomask, DHO_MTU) ||
676 get_option_uint16(ifp->ctx, &mtu,
677 state->new, state->new_len, DHO_MTU) == -1)
678 return 0;
679 return mtu;
680 }
681
682 /* Grab our routers from the DHCP message and apply any MTU value
683 * the message contains */
684 int
685 dhcp_get_routes(rb_tree_t *routes, struct interface *ifp)
686 {
687 const struct dhcp_state *state;
688
689 if ((state = D_CSTATE(ifp)) == NULL || !(state->added & STATE_ADDED))
690 return 0;
691 return get_option_routes(routes, ifp, state->new, state->new_len);
692 }
693
694 /* Assumes DHCP options */
695 static int
696 dhcp_message_add_addr(struct bootp *bootp,
697 uint8_t type, struct in_addr addr)
698 {
699 uint8_t *p;
700 size_t len;
701
702 p = bootp->vend;
703 while (*p != DHO_END) {
704 p++;
705 p += *p + 1;
706 }
707
708 len = (size_t)(p - bootp->vend);
709 if (len + 6 > sizeof(bootp->vend)) {
710 errno = ENOMEM;
711 return -1;
712 }
713
714 *p++ = type;
715 *p++ = 4;
716 memcpy(p, &addr.s_addr, 4);
717 p += 4;
718 *p = DHO_END;
719 return 0;
720 }
721
722 static ssize_t
723 make_message(struct bootp **bootpm, const struct interface *ifp, uint8_t type)
724 {
725 struct bootp *bootp;
726 uint8_t *lp, *p, *e;
727 uint8_t *n_params = NULL;
728 uint32_t ul;
729 uint16_t sz;
730 size_t len, i;
731 const struct dhcp_opt *opt;
732 struct if_options *ifo = ifp->options;
733 const struct dhcp_state *state = D_CSTATE(ifp);
734 const struct dhcp_lease *lease = &state->lease;
735 char hbuf[HOSTNAME_MAX_LEN + 1];
736 const char *hostname;
737 const struct vivco *vivco;
738 int mtu;
739 #ifdef AUTH
740 uint8_t *auth, auth_len;
741 #endif
742
743 if ((mtu = if_getmtu(ifp)) == -1)
744 logerr("%s: if_getmtu", ifp->name);
745 else if (mtu < MTU_MIN) {
746 if (if_setmtu(ifp, MTU_MIN) == -1)
747 logerr("%s: if_setmtu", ifp->name);
748 mtu = MTU_MIN;
749 }
750
751 if (ifo->options & DHCPCD_BOOTP)
752 bootp = calloc(1, sizeof (*bootp));
753 else
754 /* Make the maximal message we could send */
755 bootp = calloc(1, (size_t)(mtu - IP_UDP_SIZE));
756
757 if (bootp == NULL)
758 return -1;
759 *bootpm = bootp;
760
761 if (state->addr != NULL &&
762 (type == DHCP_INFORM || type == DHCP_RELEASE ||
763 (type == DHCP_REQUEST &&
764 state->addr->mask.s_addr == lease->mask.s_addr &&
765 (state->new == NULL || IS_DHCP(state->new)) &&
766 !(state->added & (STATE_FAKE | STATE_EXPIRED)))))
767 bootp->ciaddr = state->addr->addr.s_addr;
768
769 bootp->op = BOOTREQUEST;
770 bootp->htype = (uint8_t)ifp->hwtype;
771 if (ifp->hwlen != 0 && ifp->hwlen <= sizeof(bootp->chaddr)) {
772 bootp->hlen = (uint8_t)ifp->hwlen;
773 memcpy(&bootp->chaddr, &ifp->hwaddr, ifp->hwlen);
774 }
775
776 if (ifo->options & DHCPCD_BROADCAST &&
777 bootp->ciaddr == 0 &&
778 type != DHCP_DECLINE &&
779 type != DHCP_RELEASE)
780 bootp->flags = htons(BROADCAST_FLAG);
781
782 if (type != DHCP_DECLINE && type != DHCP_RELEASE) {
783 struct timespec tv;
784 unsigned long long secs;
785
786 clock_gettime(CLOCK_MONOTONIC, &tv);
787 secs = eloop_timespec_diff(&tv, &state->started, NULL);
788 if (secs > UINT16_MAX)
789 bootp->secs = htons((uint16_t)UINT16_MAX);
790 else
791 bootp->secs = htons((uint16_t)secs);
792 }
793
794 bootp->xid = htonl(state->xid);
795
796 if (ifo->options & DHCPCD_BOOTP)
797 return sizeof(*bootp);
798
799 p = bootp->vend;
800 e = (uint8_t *)bootp + (mtu - IP_UDP_SIZE) - 1; /* -1 for DHO_END */
801
802 ul = htonl(MAGIC_COOKIE);
803 memcpy(p, &ul, sizeof(ul));
804 p += sizeof(ul);
805
806 #define AREA_LEFT (size_t)(e - p)
807 #define AREA_FIT(s) if ((s) > AREA_LEFT) goto toobig
808 #define AREA_CHECK(s) if ((s) + 2UL > AREA_LEFT) goto toobig
809 #define PUT_ADDR(o, a) do { \
810 AREA_CHECK(4); \
811 *p++ = (o); \
812 *p++ = 4; \
813 memcpy(p, &(a)->s_addr, 4); \
814 p += 4; \
815 } while (0 /* CONSTCOND */)
816
817 /* Options are listed in numerical order as per RFC 7844 Section 3.1
818 * XXX: They should be randomised. */
819
820 bool putip = false;
821 if (lease->addr.s_addr && lease->cookie == htonl(MAGIC_COOKIE)) {
822 if (type == DHCP_DECLINE ||
823 (type == DHCP_REQUEST &&
824 (state->addr == NULL ||
825 state->added & (STATE_FAKE | STATE_EXPIRED) ||
826 lease->addr.s_addr != state->addr->addr.s_addr)))
827 {
828 putip = true;
829 PUT_ADDR(DHO_IPADDRESS, &lease->addr);
830 }
831 }
832
833 AREA_CHECK(3);
834 *p++ = DHO_MESSAGETYPE;
835 *p++ = 1;
836 *p++ = type;
837
838 if (lease->addr.s_addr && lease->cookie == htonl(MAGIC_COOKIE)) {
839 if (type == DHCP_RELEASE || putip) {
840 if (lease->server.s_addr)
841 PUT_ADDR(DHO_SERVERID, &lease->server);
842 }
843 }
844
845 if (type == DHCP_DECLINE) {
846 len = strlen(DAD);
847 if (len > AREA_LEFT) {
848 *p++ = DHO_MESSAGE;
849 *p++ = (uint8_t)len;
850 memcpy(p, DAD, len);
851 p += len;
852 }
853 }
854
855 #define DHCP_DIR(type) ((type) == DHCP_DISCOVER || (type) == DHCP_INFORM || \
856 (type) == DHCP_REQUEST)
857
858 if (DHCP_DIR(type)) {
859 /* vendor is already encoded correctly, so just add it */
860 if (ifo->vendor[0]) {
861 AREA_CHECK(ifo->vendor[0]);
862 *p++ = DHO_VENDOR;
863 memcpy(p, ifo->vendor, (size_t)ifo->vendor[0] + 1);
864 p += ifo->vendor[0] + 1;
865 }
866 }
867
868 if (type == DHCP_DISCOVER && ifo->options & DHCPCD_REQUEST)
869 PUT_ADDR(DHO_IPADDRESS, &ifo->req_addr);
870
871 if (DHCP_DIR(type)) {
872 if (type != DHCP_INFORM) {
873 if (ifo->leasetime != 0) {
874 AREA_CHECK(4);
875 *p++ = DHO_LEASETIME;
876 *p++ = 4;
877 ul = htonl(ifo->leasetime);
878 memcpy(p, &ul, 4);
879 p += 4;
880 }
881 }
882
883 AREA_CHECK(0);
884 *p++ = DHO_PARAMETERREQUESTLIST;
885 n_params = p;
886 *p++ = 0;
887 for (i = 0, opt = ifp->ctx->dhcp_opts;
888 i < ifp->ctx->dhcp_opts_len;
889 i++, opt++)
890 {
891 if (!DHC_REQOPT(opt, ifo->requestmask, ifo->nomask))
892 continue;
893 if (type == DHCP_INFORM &&
894 (opt->option == DHO_RENEWALTIME ||
895 opt->option == DHO_REBINDTIME))
896 continue;
897 AREA_FIT(1);
898 *p++ = (uint8_t)opt->option;
899 }
900 for (i = 0, opt = ifo->dhcp_override;
901 i < ifo->dhcp_override_len;
902 i++, opt++)
903 {
904 /* Check if added above */
905 for (lp = n_params + 1; lp < p; lp++)
906 if (*lp == (uint8_t)opt->option)
907 break;
908 if (lp < p)
909 continue;
910 if (!DHC_REQOPT(opt, ifo->requestmask, ifo->nomask))
911 continue;
912 if (type == DHCP_INFORM &&
913 (opt->option == DHO_RENEWALTIME ||
914 opt->option == DHO_REBINDTIME))
915 continue;
916 AREA_FIT(1);
917 *p++ = (uint8_t)opt->option;
918 }
919 *n_params = (uint8_t)(p - n_params - 1);
920
921 if (mtu != -1 &&
922 !(has_option_mask(ifo->nomask, DHO_MAXMESSAGESIZE)))
923 {
924 AREA_CHECK(2);
925 *p++ = DHO_MAXMESSAGESIZE;
926 *p++ = 2;
927 sz = htons((uint16_t)(mtu - IP_UDP_SIZE));
928 memcpy(p, &sz, 2);
929 p += 2;
930 }
931
932 if (ifo->userclass[0] &&
933 !has_option_mask(ifo->nomask, DHO_USERCLASS))
934 {
935 AREA_CHECK(ifo->userclass[0]);
936 *p++ = DHO_USERCLASS;
937 memcpy(p, ifo->userclass,
938 (size_t)ifo->userclass[0] + 1);
939 p += ifo->userclass[0] + 1;
940 }
941 }
942
943 if (state->clientid) {
944 AREA_CHECK(state->clientid[0]);
945 *p++ = DHO_CLIENTID;
946 memcpy(p, state->clientid, (size_t)state->clientid[0] + 1);
947 p += state->clientid[0] + 1;
948 }
949
950 if (DHCP_DIR(type) &&
951 !has_option_mask(ifo->nomask, DHO_VENDORCLASSID) &&
952 ifo->vendorclassid[0])
953 {
954 AREA_CHECK(ifo->vendorclassid[0]);
955 *p++ = DHO_VENDORCLASSID;
956 memcpy(p, ifo->vendorclassid, (size_t)ifo->vendorclassid[0]+1);
957 p += ifo->vendorclassid[0] + 1;
958 }
959
960 if (type == DHCP_DISCOVER &&
961 !(ifp->ctx->options & DHCPCD_TEST) &&
962 DHC_REQ(ifo->requestmask, ifo->nomask, DHO_RAPIDCOMMIT))
963 {
964 /* RFC 4039 Section 3 */
965 AREA_CHECK(0);
966 *p++ = DHO_RAPIDCOMMIT;
967 *p++ = 0;
968 }
969
970 if (DHCP_DIR(type)) {
971 hostname = dhcp_get_hostname(hbuf, sizeof(hbuf), ifo);
972
973 /*
974 * RFC4702 3.1 States that if we send the Client FQDN option
975 * then we MUST NOT also send the Host Name option.
976 * Technically we could, but that is not RFC conformant and
977 * also seems to break some DHCP server implemetations such as
978 * Windows. On the other hand, ISC dhcpd is just as non RFC
979 * conformant by not accepting a partially qualified FQDN.
980 */
981 if (ifo->fqdn != FQDN_DISABLE) {
982 /* IETF DHC-FQDN option (81), RFC4702 */
983 i = 3;
984 if (hostname)
985 i += encode_rfc1035(hostname, NULL);
986 AREA_CHECK(i);
987 *p++ = DHO_FQDN;
988 *p++ = (uint8_t)i;
989 /*
990 * Flags: 0000NEOS
991 * S: 1 => Client requests Server to update
992 * a RR in DNS as well as PTR
993 * O: 1 => Server indicates to client that
994 * DNS has been updated
995 * E: 1 => Name data is DNS format
996 * N: 1 => Client requests Server to not
997 * update DNS
998 */
999 if (hostname)
1000 *p++ = (uint8_t)((ifo->fqdn & 0x09) | 0x04);
1001 else
1002 *p++ = (FQDN_NONE & 0x09) | 0x04;
1003 *p++ = 0; /* from server for PTR RR */
1004 *p++ = 0; /* from server for A RR if S=1 */
1005 if (hostname) {
1006 i = encode_rfc1035(hostname, p);
1007 p += i;
1008 }
1009 } else if (ifo->options & DHCPCD_HOSTNAME && hostname) {
1010 len = strlen(hostname);
1011 AREA_CHECK(len);
1012 *p++ = DHO_HOSTNAME;
1013 *p++ = (uint8_t)len;
1014 memcpy(p, hostname, len);
1015 p += len;
1016 }
1017 }
1018
1019 #ifdef AUTH
1020 auth = NULL; /* appease GCC */
1021 auth_len = 0;
1022 if (ifo->auth.options & DHCPCD_AUTH_SEND) {
1023 ssize_t alen = dhcp_auth_encode(ifp->ctx, &ifo->auth,
1024 state->auth.token,
1025 NULL, 0, 4, type, NULL, 0);
1026 if (alen != -1 && alen > UINT8_MAX) {
1027 errno = ERANGE;
1028 alen = -1;
1029 }
1030 if (alen == -1)
1031 logerr("%s: dhcp_auth_encode", ifp->name);
1032 else if (alen != 0) {
1033 auth_len = (uint8_t)alen;
1034 AREA_CHECK(auth_len);
1035 *p++ = DHO_AUTHENTICATION;
1036 *p++ = auth_len;
1037 auth = p;
1038 p += auth_len;
1039 }
1040 }
1041 #endif
1042
1043 /* RFC 2563 Auto Configure */
1044 if (type == DHCP_DISCOVER && ifo->options & DHCPCD_IPV4LL &&
1045 !(has_option_mask(ifo->nomask, DHO_AUTOCONFIGURE)))
1046 {
1047 AREA_CHECK(1);
1048 *p++ = DHO_AUTOCONFIGURE;
1049 *p++ = 1;
1050 *p++ = 1;
1051 }
1052
1053 if (DHCP_DIR(type)) {
1054 if (ifo->mudurl[0]) {
1055 AREA_CHECK(ifo->mudurl[0]);
1056 *p++ = DHO_MUDURL;
1057 memcpy(p, ifo->mudurl, (size_t)ifo->mudurl[0] + 1);
1058 p += ifo->mudurl[0] + 1;
1059 }
1060
1061 if (ifo->vivco_len &&
1062 !has_option_mask(ifo->nomask, DHO_VIVCO))
1063 {
1064 AREA_CHECK(sizeof(ul));
1065 *p++ = DHO_VIVCO;
1066 lp = p++;
1067 *lp = sizeof(ul);
1068 ul = htonl(ifo->vivco_en);
1069 memcpy(p, &ul, sizeof(ul));
1070 p += sizeof(ul);
1071 for (i = 0, vivco = ifo->vivco;
1072 i < ifo->vivco_len;
1073 i++, vivco++)
1074 {
1075 AREA_FIT(vivco->len);
1076 if (vivco->len + 2 + *lp > 255) {
1077 logerrx("%s: VIVCO option too big",
1078 ifp->name);
1079 free(bootp);
1080 return -1;
1081 }
1082 *p++ = (uint8_t)vivco->len;
1083 memcpy(p, vivco->data, vivco->len);
1084 p += vivco->len;
1085 *lp = (uint8_t)(*lp + vivco->len + 1);
1086 }
1087 }
1088
1089 #ifdef AUTH
1090 if ((ifo->auth.options & DHCPCD_AUTH_SENDREQUIRE) !=
1091 DHCPCD_AUTH_SENDREQUIRE &&
1092 !has_option_mask(ifo->nomask, DHO_FORCERENEW_NONCE))
1093 {
1094 /* We support HMAC-MD5 */
1095 AREA_CHECK(1);
1096 *p++ = DHO_FORCERENEW_NONCE;
1097 *p++ = 1;
1098 *p++ = AUTH_ALG_HMAC_MD5;
1099 }
1100 #endif
1101 }
1102
1103 *p++ = DHO_END;
1104 len = (size_t)(p - (uint8_t *)bootp);
1105
1106 /* Pad out to the BOOTP message length.
1107 * Even if we send a DHCP packet with a variable length vendor area,
1108 * some servers / relay agents don't like packets smaller than
1109 * a BOOTP message which is fine because that's stipulated
1110 * in RFC1542 section 2.1. */
1111 while (len < sizeof(*bootp)) {
1112 *p++ = DHO_PAD;
1113 len++;
1114 }
1115
1116 #ifdef AUTH
1117 if (ifo->auth.options & DHCPCD_AUTH_SEND && auth_len != 0)
1118 dhcp_auth_encode(ifp->ctx, &ifo->auth, state->auth.token,
1119 (uint8_t *)bootp, len, 4, type, auth, auth_len);
1120 #endif
1121
1122 return (ssize_t)len;
1123
1124 toobig:
1125 logerrx("%s: DHCP message too big", ifp->name);
1126 free(bootp);
1127 return -1;
1128 }
1129
1130 static size_t
1131 read_lease(struct interface *ifp, struct bootp **bootp)
1132 {
1133 union {
1134 struct bootp bootp;
1135 uint8_t buf[FRAMELEN_MAX];
1136 } buf;
1137 struct dhcp_state *state = D_STATE(ifp);
1138 ssize_t sbytes;
1139 size_t bytes;
1140 uint8_t type;
1141 #ifdef AUTH
1142 const uint8_t *auth;
1143 size_t auth_len;
1144 #endif
1145
1146 /* Safety */
1147 *bootp = NULL;
1148
1149 if (state->leasefile[0] == '\0') {
1150 logdebugx("reading standard input");
1151 sbytes = read(fileno(stdin), buf.buf, sizeof(buf.buf));
1152 } else {
1153 logdebugx("%s: reading lease: %s",
1154 ifp->name, state->leasefile);
1155 sbytes = dhcp_readfile(ifp->ctx, state->leasefile,
1156 buf.buf, sizeof(buf.buf));
1157 }
1158 if (sbytes == -1) {
1159 if (errno != ENOENT)
1160 logerr("%s: %s", ifp->name, state->leasefile);
1161 return 0;
1162 }
1163 bytes = (size_t)sbytes;
1164
1165 /* Ensure the packet is at lease BOOTP sized
1166 * with a vendor area of 4 octets
1167 * (it should be more, and our read packet enforces this so this
1168 * code should not be needed, but of course people could
1169 * scribble whatever in the stored lease file. */
1170 if (bytes < DHCP_MIN_LEN) {
1171 logerrx("%s: %s: truncated lease", ifp->name, __func__);
1172 return 0;
1173 }
1174
1175 if (ifp->ctx->options & DHCPCD_DUMPLEASE)
1176 goto out;
1177
1178 /* We may have found a BOOTP server */
1179 if (get_option_uint8(ifp->ctx, &type, &buf.bootp, bytes,
1180 DHO_MESSAGETYPE) == -1)
1181 type = 0;
1182
1183 #ifdef AUTH
1184 /* Authenticate the message */
1185 auth = get_option(ifp->ctx, &buf.bootp, bytes,
1186 DHO_AUTHENTICATION, &auth_len);
1187 if (auth) {
1188 if (dhcp_auth_validate(&state->auth, &ifp->options->auth,
1189 &buf.bootp, bytes, 4, type, auth, auth_len) == NULL)
1190 {
1191 logerr("%s: authentication failed", ifp->name);
1192 return 0;
1193 }
1194 if (state->auth.token)
1195 logdebugx("%s: validated using 0x%08" PRIu32,
1196 ifp->name, state->auth.token->secretid);
1197 else
1198 logdebugx("%s: accepted reconfigure key", ifp->name);
1199 } else if ((ifp->options->auth.options & DHCPCD_AUTH_SENDREQUIRE) ==
1200 DHCPCD_AUTH_SENDREQUIRE)
1201 {
1202 logerrx("%s: authentication now required", ifp->name);
1203 return 0;
1204 }
1205 #endif
1206
1207 out:
1208 *bootp = malloc(bytes);
1209 if (*bootp == NULL) {
1210 logerr(__func__);
1211 return 0;
1212 }
1213 memcpy(*bootp, buf.buf, bytes);
1214 return bytes;
1215 }
1216
1217 static const struct dhcp_opt *
1218 dhcp_getoverride(const struct if_options *ifo, unsigned int o)
1219 {
1220 size_t i;
1221 const struct dhcp_opt *opt;
1222
1223 for (i = 0, opt = ifo->dhcp_override;
1224 i < ifo->dhcp_override_len;
1225 i++, opt++)
1226 {
1227 if (opt->option == o)
1228 return opt;
1229 }
1230 return NULL;
1231 }
1232
1233 static const uint8_t *
1234 dhcp_getoption(struct dhcpcd_ctx *ctx,
1235 size_t *os, unsigned int *code, size_t *len,
1236 const uint8_t *od, size_t ol, struct dhcp_opt **oopt)
1237 {
1238 size_t i;
1239 struct dhcp_opt *opt;
1240
1241 if (od) {
1242 if (ol < 2) {
1243 errno = EINVAL;
1244 return NULL;
1245 }
1246 *os = 2; /* code + len */
1247 *code = (unsigned int)*od++;
1248 *len = (size_t)*od++;
1249 if (*len > ol - *os) {
1250 errno = ERANGE;
1251 return NULL;
1252 }
1253 }
1254
1255 *oopt = NULL;
1256 for (i = 0, opt = ctx->dhcp_opts; i < ctx->dhcp_opts_len; i++, opt++) {
1257 if (opt->option == *code) {
1258 *oopt = opt;
1259 break;
1260 }
1261 }
1262
1263 return od;
1264 }
1265
1266 ssize_t
1267 dhcp_env(FILE *fenv, const char *prefix, const struct interface *ifp,
1268 const struct bootp *bootp, size_t bootp_len)
1269 {
1270 const struct if_options *ifo;
1271 const uint8_t *p;
1272 struct in_addr addr;
1273 struct in_addr net;
1274 struct in_addr brd;
1275 struct dhcp_opt *opt, *vo;
1276 size_t i, pl;
1277 char safe[(BOOTP_FILE_LEN * 4) + 1];
1278 uint8_t overl = 0;
1279 uint32_t en;
1280
1281 ifo = ifp->options;
1282 if (get_option_uint8(ifp->ctx, &overl, bootp, bootp_len,
1283 DHO_OPTSOVERLOADED) == -1)
1284 overl = 0;
1285
1286 if (bootp->yiaddr || bootp->ciaddr) {
1287 /* Set some useful variables that we derive from the DHCP
1288 * message but are not necessarily in the options */
1289 addr.s_addr = bootp->yiaddr ? bootp->yiaddr : bootp->ciaddr;
1290 if (efprintf(fenv, "%s_ip_address=%s",
1291 prefix, inet_ntoa(addr)) == -1)
1292 return -1;
1293 if (get_option_addr(ifp->ctx, &net,
1294 bootp, bootp_len, DHO_SUBNETMASK) == -1) {
1295 net.s_addr = ipv4_getnetmask(addr.s_addr);
1296 if (efprintf(fenv, "%s_subnet_mask=%s",
1297 prefix, inet_ntoa(net)) == -1)
1298 return -1;
1299 }
1300 if (efprintf(fenv, "%s_subnet_cidr=%d",
1301 prefix, inet_ntocidr(net))== -1)
1302 return -1;
1303 if (get_option_addr(ifp->ctx, &brd,
1304 bootp, bootp_len, DHO_BROADCAST) == -1)
1305 {
1306 brd.s_addr = addr.s_addr | ~net.s_addr;
1307 if (efprintf(fenv, "%s_broadcast_address=%s",
1308 prefix, inet_ntoa(brd)) == -1)
1309 return -1;
1310 }
1311 addr.s_addr = bootp->yiaddr & net.s_addr;
1312 if (efprintf(fenv, "%s_network_number=%s",
1313 prefix, inet_ntoa(addr)) == -1)
1314 return -1;
1315 }
1316
1317 if (*bootp->file && !(overl & 1)) {
1318 print_string(safe, sizeof(safe), OT_STRING,
1319 bootp->file, sizeof(bootp->file));
1320 if (efprintf(fenv, "%s_filename=%s", prefix, safe) == -1)
1321 return -1;
1322 }
1323 if (*bootp->sname && !(overl & 2)) {
1324 print_string(safe, sizeof(safe), OT_STRING | OT_DOMAIN,
1325 bootp->sname, sizeof(bootp->sname));
1326 if (efprintf(fenv, "%s_server_name=%s", prefix, safe) == -1)
1327 return -1;
1328 }
1329
1330 /* Zero our indexes */
1331 for (i = 0, opt = ifp->ctx->dhcp_opts;
1332 i < ifp->ctx->dhcp_opts_len;
1333 i++, opt++)
1334 dhcp_zero_index(opt);
1335 for (i = 0, opt = ifp->options->dhcp_override;
1336 i < ifp->options->dhcp_override_len;
1337 i++, opt++)
1338 dhcp_zero_index(opt);
1339 for (i = 0, opt = ifp->ctx->vivso;
1340 i < ifp->ctx->vivso_len;
1341 i++, opt++)
1342 dhcp_zero_index(opt);
1343
1344 for (i = 0, opt = ifp->ctx->dhcp_opts;
1345 i < ifp->ctx->dhcp_opts_len;
1346 i++, opt++)
1347 {
1348 if (has_option_mask(ifo->nomask, opt->option))
1349 continue;
1350 if (dhcp_getoverride(ifo, opt->option))
1351 continue;
1352 p = get_option(ifp->ctx, bootp, bootp_len, opt->option, &pl);
1353 if (p == NULL)
1354 continue;
1355 dhcp_envoption(ifp->ctx, fenv, prefix, ifp->name,
1356 opt, dhcp_getoption, p, pl);
1357
1358 if (opt->option != DHO_VIVSO || pl <= (int)sizeof(uint32_t))
1359 continue;
1360 memcpy(&en, p, sizeof(en));
1361 en = ntohl(en);
1362 vo = vivso_find(en, ifp);
1363 if (vo == NULL)
1364 continue;
1365 /* Skip over en + total size */
1366 p += sizeof(en) + 1;
1367 pl -= sizeof(en) + 1;
1368 dhcp_envoption(ifp->ctx, fenv, prefix, ifp->name,
1369 vo, dhcp_getoption, p, pl);
1370 }
1371
1372 for (i = 0, opt = ifo->dhcp_override;
1373 i < ifo->dhcp_override_len;
1374 i++, opt++)
1375 {
1376 if (has_option_mask(ifo->nomask, opt->option))
1377 continue;
1378 p = get_option(ifp->ctx, bootp, bootp_len, opt->option, &pl);
1379 if (p == NULL)
1380 continue;
1381 dhcp_envoption(ifp->ctx, fenv, prefix, ifp->name,
1382 opt, dhcp_getoption, p, pl);
1383 }
1384
1385 return 1;
1386 }
1387
1388 static void
1389 get_lease(struct interface *ifp,
1390 struct dhcp_lease *lease, const struct bootp *bootp, size_t len)
1391 {
1392 struct dhcpcd_ctx *ctx;
1393
1394 assert(bootp != NULL);
1395
1396 memcpy(&lease->cookie, bootp->vend, sizeof(lease->cookie));
1397 /* BOOTP does not set yiaddr for replies when ciaddr is set. */
1398 lease->addr.s_addr = bootp->yiaddr ? bootp->yiaddr : bootp->ciaddr;
1399 ctx = ifp->ctx;
1400 if (ifp->options->options & (DHCPCD_STATIC | DHCPCD_INFORM)) {
1401 if (ifp->options->req_addr.s_addr != INADDR_ANY) {
1402 lease->mask = ifp->options->req_mask;
1403 if (ifp->options->req_brd.s_addr != INADDR_ANY)
1404 lease->brd = ifp->options->req_brd;
1405 else
1406 lease->brd.s_addr =
1407 lease->addr.s_addr | ~lease->mask.s_addr;
1408 } else {
1409 const struct ipv4_addr *ia;
1410
1411 ia = ipv4_iffindaddr(ifp, &lease->addr, NULL);
1412 assert(ia != NULL);
1413 lease->mask = ia->mask;
1414 lease->brd = ia->brd;
1415 }
1416 } else {
1417 if (get_option_addr(ctx, &lease->mask, bootp, len,
1418 DHO_SUBNETMASK) == -1)
1419 lease->mask.s_addr =
1420 ipv4_getnetmask(lease->addr.s_addr);
1421 if (get_option_addr(ctx, &lease->brd, bootp, len,
1422 DHO_BROADCAST) == -1)
1423 lease->brd.s_addr =
1424 lease->addr.s_addr | ~lease->mask.s_addr;
1425 }
1426 if (get_option_uint32(ctx, &lease->leasetime,
1427 bootp, len, DHO_LEASETIME) != 0)
1428 lease->leasetime = DHCP_INFINITE_LIFETIME;
1429 if (get_option_uint32(ctx, &lease->renewaltime,
1430 bootp, len, DHO_RENEWALTIME) != 0)
1431 lease->renewaltime = 0;
1432 if (get_option_uint32(ctx, &lease->rebindtime,
1433 bootp, len, DHO_REBINDTIME) != 0)
1434 lease->rebindtime = 0;
1435 if (get_option_addr(ctx, &lease->server, bootp, len, DHO_SERVERID) != 0)
1436 lease->server.s_addr = INADDR_ANY;
1437 }
1438
1439 static const char *
1440 get_dhcp_op(uint8_t type)
1441 {
1442 const struct dhcp_op *d;
1443
1444 for (d = dhcp_ops; d->name; d++)
1445 if (d->value == type)
1446 return d->name;
1447 return NULL;
1448 }
1449
1450 static void
1451 dhcp_fallback(void *arg)
1452 {
1453 struct interface *iface;
1454
1455 iface = (struct interface *)arg;
1456 dhcpcd_selectprofile(iface, iface->options->fallback);
1457 dhcpcd_startinterface(iface);
1458 }
1459
1460 static void
1461 dhcp_new_xid(struct interface *ifp)
1462 {
1463 struct dhcp_state *state;
1464 const struct interface *ifp1;
1465 const struct dhcp_state *state1;
1466
1467 state = D_STATE(ifp);
1468 if (ifp->options->options & DHCPCD_XID_HWADDR &&
1469 ifp->hwlen >= sizeof(state->xid))
1470 /* The lower bits are probably more unique on the network */
1471 memcpy(&state->xid,
1472 (ifp->hwaddr + ifp->hwlen) - sizeof(state->xid),
1473 sizeof(state->xid));
1474 else {
1475 again:
1476 state->xid = arc4random();
1477 }
1478
1479 /* Ensure it's unique */
1480 TAILQ_FOREACH(ifp1, ifp->ctx->ifaces, next) {
1481 if (ifp == ifp1)
1482 continue;
1483 if ((state1 = D_CSTATE(ifp1)) == NULL)
1484 continue;
1485 if (state1->xid == state->xid)
1486 break;
1487 }
1488 if (ifp1 != NULL) {
1489 if (ifp->options->options & DHCPCD_XID_HWADDR &&
1490 ifp->hwlen >= sizeof(state->xid))
1491 {
1492 logerrx("%s: duplicate xid on %s",
1493 ifp->name, ifp1->name);
1494 return;
1495 }
1496 goto again;
1497 }
1498
1499 /* We can't do this when sharing leases across interfaes */
1500 #if 0
1501 /* As the XID changes, re-apply the filter. */
1502 if (state->bpf_fd != -1) {
1503 if (bpf_bootp(ifp, state->bpf_fd) == -1)
1504 logerr(__func__); /* try to continue */
1505 }
1506 #endif
1507 }
1508
1509 static void
1510 dhcp_closebpf(struct interface *ifp)
1511 {
1512 struct dhcpcd_ctx *ctx = ifp->ctx;
1513 struct dhcp_state *state = D_STATE(ifp);
1514
1515 #ifdef PRIVSEP
1516 if (IN_PRIVSEP_SE(ctx))
1517 ps_bpf_closebootp(ifp);
1518 #endif
1519
1520 if (state->bpf != NULL) {
1521 eloop_event_delete(ctx->eloop, state->bpf->bpf_fd);
1522 bpf_close(state->bpf);
1523 state->bpf = NULL;
1524 }
1525 }
1526
1527 static void
1528 dhcp_closeinet(struct interface *ifp)
1529 {
1530 struct dhcpcd_ctx *ctx = ifp->ctx;
1531 struct dhcp_state *state = D_STATE(ifp);
1532
1533 #ifdef PRIVSEP
1534 if (IN_PRIVSEP_SE(ctx)) {
1535 if (state->addr != NULL)
1536 ps_inet_closebootp(state->addr);
1537 }
1538 #endif
1539
1540 if (state->udp_rfd != -1) {
1541 eloop_event_delete(ctx->eloop, state->udp_rfd);
1542 close(state->udp_rfd);
1543 state->udp_rfd = -1;
1544 }
1545 }
1546
1547 void
1548 dhcp_close(struct interface *ifp)
1549 {
1550 struct dhcp_state *state = D_STATE(ifp);
1551
1552 if (state == NULL)
1553 return;
1554
1555 dhcp_closebpf(ifp);
1556 dhcp_closeinet(ifp);
1557
1558 state->interval = 0;
1559 }
1560
1561 int
1562 dhcp_openudp(struct in_addr *ia)
1563 {
1564 int s;
1565 struct sockaddr_in sin;
1566 int n;
1567
1568 if ((s = xsocket(PF_INET, SOCK_DGRAM | SOCK_CXNB, IPPROTO_UDP)) == -1)
1569 return -1;
1570
1571 n = 1;
1572 if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &n, sizeof(n)) == -1)
1573 goto errexit;
1574 #ifdef IP_RECVIF
1575 if (setsockopt(s, IPPROTO_IP, IP_RECVIF, &n, sizeof(n)) == -1)
1576 goto errexit;
1577 #else
1578 if (setsockopt(s, IPPROTO_IP, IP_RECVPKTINFO, &n, sizeof(n)) == -1)
1579 goto errexit;
1580 #endif
1581 #ifdef SO_RERROR
1582 if (setsockopt(s, SOL_SOCKET, SO_RERROR, &n, sizeof(n)) == -1)
1583 goto errexit;
1584 #endif
1585
1586 memset(&sin, 0, sizeof(sin));
1587 sin.sin_family = AF_INET;
1588 sin.sin_port = htons(BOOTPC);
1589 if (ia != NULL)
1590 sin.sin_addr = *ia;
1591 if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) == -1)
1592 goto errexit;
1593
1594 return s;
1595
1596 errexit:
1597 close(s);
1598 return -1;
1599 }
1600
1601 static uint16_t
1602 in_cksum(const void *data, size_t len, uint32_t *isum)
1603 {
1604 const uint16_t *word = data;
1605 uint32_t sum = isum != NULL ? *isum : 0;
1606
1607 for (; len > 1; len -= sizeof(*word))
1608 sum += *word++;
1609
1610 if (len == 1)
1611 sum += htons((uint16_t)(*(const uint8_t *)word << 8));
1612
1613 if (isum != NULL)
1614 *isum = sum;
1615
1616 sum = (sum >> 16) + (sum & 0xffff);
1617 sum += (sum >> 16);
1618
1619 return (uint16_t)~sum;
1620 }
1621
1622 static struct bootp_pkt *
1623 dhcp_makeudppacket(size_t *sz, const uint8_t *data, size_t length,
1624 struct in_addr source, struct in_addr dest)
1625 {
1626 struct bootp_pkt *udpp;
1627 struct ip *ip;
1628 struct udphdr *udp;
1629
1630 if ((udpp = calloc(1, sizeof(*ip) + sizeof(*udp) + length)) == NULL)
1631 return NULL;
1632 ip = &udpp->ip;
1633 udp = &udpp->udp;
1634
1635 /* OK, this is important :)
1636 * We copy the data to our packet and then create a small part of the
1637 * ip structure and an invalid ip_len (basically udp length).
1638 * We then fill the udp structure and put the checksum
1639 * of the whole packet into the udp checksum.
1640 * Finally we complete the ip structure and ip checksum.
1641 * If we don't do the ordering like so then the udp checksum will be
1642 * broken, so find another way of doing it! */
1643
1644 memcpy(&udpp->bootp, data, length);
1645
1646 ip->ip_p = IPPROTO_UDP;
1647 ip->ip_src.s_addr = source.s_addr;
1648 if (dest.s_addr == 0)
1649 ip->ip_dst.s_addr = INADDR_BROADCAST;
1650 else
1651 ip->ip_dst.s_addr = dest.s_addr;
1652
1653 udp->uh_sport = htons(BOOTPC);
1654 udp->uh_dport = htons(BOOTPS);
1655 udp->uh_ulen = htons((uint16_t)(sizeof(*udp) + length));
1656 ip->ip_len = udp->uh_ulen;
1657 udp->uh_sum = in_cksum(udpp, sizeof(*ip) + sizeof(*udp) + length, NULL);
1658
1659 ip->ip_v = IPVERSION;
1660 ip->ip_hl = sizeof(*ip) >> 2;
1661 ip->ip_id = (uint16_t)arc4random_uniform(UINT16_MAX);
1662 ip->ip_ttl = IPDEFTTL;
1663 ip->ip_len = htons((uint16_t)(sizeof(*ip) + sizeof(*udp) + length));
1664 ip->ip_sum = in_cksum(ip, sizeof(*ip), NULL);
1665 if (ip->ip_sum == 0)
1666 ip->ip_sum = 0xffff; /* RFC 768 */
1667
1668 *sz = sizeof(*ip) + sizeof(*udp) + length;
1669 return udpp;
1670 }
1671
1672 static ssize_t
1673 dhcp_sendudp(struct interface *ifp, struct in_addr *to, void *data, size_t len)
1674 {
1675 struct sockaddr_in sin = {
1676 .sin_family = AF_INET,
1677 .sin_addr = *to,
1678 .sin_port = htons(BOOTPS),
1679 #ifdef HAVE_SA_LEN
1680 .sin_len = sizeof(sin),
1681 #endif
1682 };
1683 struct udphdr udp = {
1684 .uh_sport = htons(BOOTPC),
1685 .uh_dport = htons(BOOTPS),
1686 .uh_ulen = htons((uint16_t)(sizeof(udp) + len)),
1687 };
1688 struct iovec iov[] = {
1689 { .iov_base = &udp, .iov_len = sizeof(udp), },
1690 { .iov_base = data, .iov_len = len, },
1691 };
1692 struct msghdr msg = {
1693 .msg_name = (void *)&sin,
1694 .msg_namelen = sizeof(sin),
1695 .msg_iov = iov,
1696 .msg_iovlen = __arraycount(iov),
1697 };
1698 struct dhcpcd_ctx *ctx = ifp->ctx;
1699
1700 #ifdef PRIVSEP
1701 if (ctx->options & DHCPCD_PRIVSEP)
1702 return ps_inet_sendbootp(ifp, &msg);
1703 #endif
1704 return sendmsg(ctx->udp_wfd, &msg, 0);
1705 }
1706
1707 static void
1708 send_message(struct interface *ifp, uint8_t type,
1709 void (*callback)(void *))
1710 {
1711 struct dhcp_state *state = D_STATE(ifp);
1712 struct if_options *ifo = ifp->options;
1713 struct bootp *bootp;
1714 struct bootp_pkt *udp;
1715 size_t len, ulen;
1716 ssize_t r;
1717 struct in_addr from, to;
1718 unsigned int RT;
1719
1720 if (callback == NULL) {
1721 /* No carrier? Don't bother sending the packet. */
1722 if (!if_is_link_up(ifp))
1723 return;
1724 logdebugx("%s: sending %s with xid 0x%x",
1725 ifp->name,
1726 ifo->options & DHCPCD_BOOTP ? "BOOTP" : get_dhcp_op(type),
1727 state->xid);
1728 RT = 0; /* bogus gcc warning */
1729 } else {
1730 if (state->interval == 0)
1731 state->interval = 4;
1732 else {
1733 state->interval *= 2;
1734 if (state->interval > 64)
1735 state->interval = 64;
1736 }
1737 RT = (state->interval * MSEC_PER_SEC) +
1738 (arc4random_uniform(MSEC_PER_SEC * 2) - MSEC_PER_SEC);
1739 /* No carrier? Don't bother sending the packet.
1740 * However, we do need to advance the timeout. */
1741 if (!if_is_link_up(ifp))
1742 goto fail;
1743 logdebugx("%s: sending %s (xid 0x%x), next in %0.1f seconds",
1744 ifp->name,
1745 ifo->options & DHCPCD_BOOTP ? "BOOTP" : get_dhcp_op(type),
1746 state->xid,
1747 (float)RT / MSEC_PER_SEC);
1748 }
1749
1750 r = make_message(&bootp, ifp, type);
1751 if (r == -1)
1752 goto fail;
1753 len = (size_t)r;
1754
1755 if (!(state->added & (STATE_FAKE | STATE_EXPIRED)) &&
1756 state->addr != NULL &&
1757 ipv4_iffindaddr(ifp, &state->lease.addr, NULL) != NULL)
1758 from.s_addr = state->lease.addr.s_addr;
1759 else
1760 from.s_addr = INADDR_ANY;
1761 if (from.s_addr != INADDR_ANY &&
1762 state->lease.server.s_addr != INADDR_ANY)
1763 to.s_addr = state->lease.server.s_addr;
1764 else
1765 to.s_addr = INADDR_BROADCAST;
1766
1767 /*
1768 * If not listening on the unspecified address we can
1769 * only receive broadcast messages via BPF.
1770 * Sockets bound to an address cannot receive broadcast messages
1771 * even if they are setup to send them.
1772 * Broadcasting from UDP is only an optimisation for rebinding
1773 * and on BSD, at least, is reliant on the subnet route being
1774 * correctly configured to receive the unicast reply.
1775 * As such, we always broadcast and receive the reply to it via BPF.
1776 * This also guarantees we have a DHCP server attached to the
1777 * interface we want to configure because we can't dictate the
1778 * interface via IP_PKTINFO unlike for IPv6.
1779 */
1780 if (to.s_addr != INADDR_BROADCAST) {
1781 if (dhcp_sendudp(ifp, &to, bootp, len) != -1)
1782 goto out;
1783 logerr("%s: dhcp_sendudp", ifp->name);
1784 }
1785
1786 if (dhcp_openbpf(ifp) == -1)
1787 goto out;
1788
1789 udp = dhcp_makeudppacket(&ulen, (uint8_t *)bootp, len, from, to);
1790 if (udp == NULL) {
1791 logerr("%s: dhcp_makeudppacket", ifp->name);
1792 r = 0;
1793 #ifdef PRIVSEP
1794 } else if (ifp->ctx->options & DHCPCD_PRIVSEP) {
1795 r = ps_bpf_sendbootp(ifp, udp, ulen);
1796 free(udp);
1797 #endif
1798 } else {
1799 r = bpf_send(state->bpf, ETHERTYPE_IP, udp, ulen);
1800 free(udp);
1801 }
1802 /* If we failed to send a raw packet this normally means
1803 * we don't have the ability to work beneath the IP layer
1804 * for this interface.
1805 * As such we remove it from consideration without actually
1806 * stopping the interface. */
1807 if (r == -1) {
1808 logerr("%s: bpf_send", ifp->name);
1809 switch(errno) {
1810 case ENETDOWN:
1811 case ENETRESET:
1812 case ENETUNREACH:
1813 case ENOBUFS:
1814 break;
1815 default:
1816 if (!(ifp->ctx->options & DHCPCD_TEST))
1817 dhcp_drop(ifp, "FAIL");
1818 eloop_timeout_delete(ifp->ctx->eloop,
1819 NULL, ifp);
1820 callback = NULL;
1821 }
1822 }
1823
1824 out:
1825 free(bootp);
1826
1827 fail:
1828 /* Even if we fail to send a packet we should continue as we are
1829 * as our failure timeouts will change out codepath when needed. */
1830 if (callback != NULL)
1831 eloop_timeout_add_msec(ifp->ctx->eloop, RT, callback, ifp);
1832 }
1833
1834 static void
1835 send_inform(void *arg)
1836 {
1837
1838 send_message((struct interface *)arg, DHCP_INFORM, send_inform);
1839 }
1840
1841 static void
1842 send_discover(void *arg)
1843 {
1844
1845 send_message((struct interface *)arg, DHCP_DISCOVER, send_discover);
1846 }
1847
1848 static void
1849 send_request(void *arg)
1850 {
1851
1852 send_message((struct interface *)arg, DHCP_REQUEST, send_request);
1853 }
1854
1855 static void
1856 send_renew(void *arg)
1857 {
1858
1859 send_message((struct interface *)arg, DHCP_REQUEST, send_renew);
1860 }
1861
1862 static void
1863 send_rebind(void *arg)
1864 {
1865
1866 send_message((struct interface *)arg, DHCP_REQUEST, send_rebind);
1867 }
1868
1869 void
1870 dhcp_discover(void *arg)
1871 {
1872 struct interface *ifp = arg;
1873 struct dhcp_state *state = D_STATE(ifp);
1874 struct if_options *ifo = ifp->options;
1875
1876 state->state = DHS_DISCOVER;
1877 dhcp_new_xid(ifp);
1878 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
1879 if (!(state->added & STATE_EXPIRED)) {
1880 if (ifo->fallback)
1881 eloop_timeout_add_sec(ifp->ctx->eloop,
1882 ifo->reboot, dhcp_fallback, ifp);
1883 #ifdef IPV4LL
1884 else if (ifo->options & DHCPCD_IPV4LL)
1885 eloop_timeout_add_sec(ifp->ctx->eloop,
1886 ifo->reboot, ipv4ll_start, ifp);
1887 #endif
1888 }
1889 if (ifo->options & DHCPCD_REQUEST)
1890 loginfox("%s: soliciting a DHCP lease (requesting %s)",
1891 ifp->name, inet_ntoa(ifo->req_addr));
1892 else
1893 loginfox("%s: soliciting a %s lease",
1894 ifp->name, ifo->options & DHCPCD_BOOTP ? "BOOTP" : "DHCP");
1895 send_discover(ifp);
1896 }
1897
1898 static void
1899 dhcp_request(void *arg)
1900 {
1901 struct interface *ifp = arg;
1902 struct dhcp_state *state = D_STATE(ifp);
1903
1904 state->state = DHS_REQUEST;
1905 send_request(ifp);
1906 }
1907
1908 static void
1909 dhcp_expire(void *arg)
1910 {
1911 struct interface *ifp = arg;
1912 struct dhcp_state *state = D_STATE(ifp);
1913
1914 if (ifp->options->options & DHCPCD_LASTLEASE_EXTEND) {
1915 logwarnx("%s: DHCP lease expired, extending lease", ifp->name);
1916 state->added |= STATE_EXPIRED;
1917 } else {
1918 logerrx("%s: DHCP lease expired", ifp->name);
1919 dhcp_drop(ifp, "EXPIRE");
1920 dhcp_unlink(ifp->ctx, state->leasefile);
1921 }
1922 state->interval = 0;
1923 dhcp_discover(ifp);
1924 }
1925
1926 #if defined(ARP) || defined(IN_IFF_DUPLICATED)
1927 static void
1928 dhcp_decline(struct interface *ifp)
1929 {
1930
1931 send_message(ifp, DHCP_DECLINE, NULL);
1932 }
1933 #endif
1934
1935 static void
1936 dhcp_startrenew(void *arg)
1937 {
1938 struct interface *ifp = arg;
1939 struct dhcp_state *state;
1940 struct dhcp_lease *lease;
1941
1942 if ((state = D_STATE(ifp)) == NULL)
1943 return;
1944
1945 /* Only renew in the bound or renew states */
1946 if (state->state != DHS_BOUND &&
1947 state->state != DHS_RENEW)
1948 return;
1949
1950 /* Remove the timeout as the renew may have been forced. */
1951 eloop_timeout_delete(ifp->ctx->eloop, dhcp_startrenew, ifp);
1952
1953 lease = &state->lease;
1954 logdebugx("%s: renewing lease of %s", ifp->name,
1955 inet_ntoa(lease->addr));
1956 state->state = DHS_RENEW;
1957 dhcp_new_xid(ifp);
1958 state->interval = 0;
1959 send_renew(ifp);
1960 }
1961
1962 void
1963 dhcp_renew(struct interface *ifp)
1964 {
1965
1966 dhcp_startrenew(ifp);
1967 }
1968
1969 static void
1970 dhcp_rebind(void *arg)
1971 {
1972 struct interface *ifp = arg;
1973 struct dhcp_state *state = D_STATE(ifp);
1974 struct dhcp_lease *lease = &state->lease;
1975
1976 logwarnx("%s: failed to renew DHCP, rebinding", ifp->name);
1977 logdebugx("%s: expire in %"PRIu32" seconds",
1978 ifp->name, lease->leasetime - lease->rebindtime);
1979 state->state = DHS_REBIND;
1980 eloop_timeout_delete(ifp->ctx->eloop, send_renew, ifp);
1981 state->lease.server.s_addr = INADDR_ANY;
1982 state->interval = 0;
1983 ifp->options->options &= ~(DHCPCD_CSR_WARNED |
1984 DHCPCD_ROUTER_HOST_ROUTE_WARNED);
1985 send_rebind(ifp);
1986 }
1987
1988 #if defined(ARP) || defined(IN_IFF_DUPLICATED)
1989 static void
1990 dhcp_finish_dad(struct interface *ifp, struct in_addr *ia)
1991 {
1992 struct dhcp_state *state = D_STATE(ifp);
1993
1994 if (state->state == DHS_BOUND)
1995 return;
1996 if (state->offer == NULL || state->offer->yiaddr != ia->s_addr)
1997 return;
1998
1999 logdebugx("%s: DAD completed for %s", ifp->name, inet_ntoa(*ia));
2000 if (!(ifp->options->options & DHCPCD_INFORM))
2001 dhcp_bind(ifp);
2002 #ifndef IN_IFF_DUPLICATED
2003 else {
2004 struct bootp *bootp;
2005 size_t len;
2006
2007 bootp = state->new;
2008 len = state->new_len;
2009 state->new = state->offer;
2010 state->new_len = state->offer_len;
2011 get_lease(ifp, &state->lease, state->new, state->new_len);
2012 ipv4_applyaddr(ifp);
2013 state->new = bootp;
2014 state->new_len = len;
2015 }
2016 #endif
2017
2018 #ifdef IPV4LL
2019 /* Stop IPv4LL now we have a working DHCP address */
2020 if (!IN_LINKLOCAL(ntohl(ia->s_addr)))
2021 ipv4ll_drop(ifp);
2022 #endif
2023
2024 if (ifp->options->options & DHCPCD_INFORM)
2025 dhcp_inform(ifp);
2026 }
2027
2028 static bool
2029 dhcp_addr_duplicated(struct interface *ifp, struct in_addr *ia)
2030 {
2031 struct dhcp_state *state = D_STATE(ifp);
2032 unsigned long long opts = ifp->options->options;
2033 struct dhcpcd_ctx *ctx = ifp->ctx;
2034 bool deleted = false;
2035 #ifdef IN_IFF_DUPLICATED
2036 struct ipv4_addr *iap;
2037 #endif
2038
2039 if ((state->offer == NULL || state->offer->yiaddr != ia->s_addr) &&
2040 !IN_ARE_ADDR_EQUAL(ia, &state->lease.addr))
2041 return deleted;
2042
2043 /* RFC 2131 3.1.5, Client-server interaction */
2044 logerrx("%s: DAD detected %s", ifp->name, inet_ntoa(*ia));
2045 dhcp_unlink(ifp->ctx, state->leasefile);
2046 if (!(opts & DHCPCD_STATIC) && !state->lease.frominfo)
2047 dhcp_decline(ifp);
2048 #ifdef IN_IFF_DUPLICATED
2049 if ((iap = ipv4_iffindaddr(ifp, ia, NULL)) != NULL) {
2050 ipv4_deladdr(iap, 0);
2051 deleted = true;
2052 }
2053 #endif
2054 eloop_timeout_delete(ctx->eloop, NULL, ifp);
2055 if (opts & (DHCPCD_STATIC | DHCPCD_INFORM)) {
2056 state->reason = "EXPIRE";
2057 script_runreason(ifp, state->reason);
2058 #define NOT_ONLY_SELF (DHCPCD_MANAGER | DHCPCD_IPV6RS | DHCPCD_DHCP6)
2059 if (!(ctx->options & NOT_ONLY_SELF))
2060 eloop_exit(ifp->ctx->eloop, EXIT_FAILURE);
2061 return deleted;
2062 }
2063 eloop_timeout_add_sec(ifp->ctx->eloop,
2064 DHCP_RAND_MAX, dhcp_discover, ifp);
2065 return deleted;
2066 }
2067 #endif
2068
2069 #ifdef ARP
2070 #ifdef KERNEL_RFC5227
2071 #ifdef ARPING
2072 static void
2073 dhcp_arp_announced(struct arp_state *state)
2074 {
2075
2076 arp_free(state);
2077 }
2078 #endif
2079 #else
2080 static void
2081 dhcp_arp_defend_failed(struct arp_state *astate)
2082 {
2083 struct interface *ifp = astate->iface;
2084
2085 dhcp_drop(ifp, "EXPIRED");
2086 dhcp_start1(ifp);
2087 }
2088 #endif
2089
2090 #if !defined(KERNEL_RFC5227) || defined(ARPING)
2091 static void dhcp_arp_not_found(struct arp_state *);
2092
2093 static struct arp_state *
2094 dhcp_arp_new(struct interface *ifp, struct in_addr *addr)
2095 {
2096 struct arp_state *astate;
2097
2098 astate = arp_new(ifp, addr);
2099 if (astate == NULL)
2100 return NULL;
2101
2102 astate->found_cb = dhcp_arp_found;
2103 astate->not_found_cb = dhcp_arp_not_found;
2104 #ifdef KERNEL_RFC5227
2105 astate->announced_cb = dhcp_arp_announced;
2106 #else
2107 astate->announced_cb = NULL;
2108 astate->defend_failed_cb = dhcp_arp_defend_failed;
2109 #endif
2110 return astate;
2111 }
2112 #endif
2113
2114 #ifdef ARPING
2115 static int
2116 dhcp_arping(struct interface *ifp)
2117 {
2118 struct dhcp_state *state;
2119 struct if_options *ifo;
2120 struct arp_state *astate;
2121 struct in_addr addr;
2122
2123 state = D_STATE(ifp);
2124 ifo = ifp->options;
2125
2126 if (ifo->arping_len == 0 || state->arping_index > ifo->arping_len)
2127 return 0;
2128
2129 if (state->arping_index + 1 == ifo->arping_len) {
2130 state->arping_index++;
2131 dhcpcd_startinterface(ifp);
2132 return 1;
2133 }
2134
2135 addr.s_addr = ifo->arping[++state->arping_index];
2136 astate = dhcp_arp_new(ifp, &addr);
2137 if (astate == NULL) {
2138 logerr(__func__);
2139 return -1;
2140 }
2141 arp_probe(astate);
2142 return 1;
2143 }
2144 #endif
2145
2146 #if !defined(KERNEL_RFC5227) || defined(ARPING)
2147 static void
2148 dhcp_arp_not_found(struct arp_state *astate)
2149 {
2150 struct interface *ifp;
2151
2152 ifp = astate->iface;
2153 #ifdef ARPING
2154 if (dhcp_arping(ifp) == 1) {
2155 arp_free(astate);
2156 return;
2157 }
2158 #endif
2159
2160 dhcp_finish_dad(ifp, &astate->addr);
2161 }
2162
2163 static void
2164 dhcp_arp_found(struct arp_state *astate, const struct arp_msg *amsg)
2165 {
2166 struct in_addr addr;
2167 struct interface *ifp = astate->iface;
2168 #ifdef ARPING
2169 struct dhcp_state *state;
2170 struct if_options *ifo;
2171
2172 state = D_STATE(ifp);
2173
2174 ifo = ifp->options;
2175 if (state->arping_index != -1 &&
2176 state->arping_index < ifo->arping_len &&
2177 amsg &&
2178 amsg->sip.s_addr == ifo->arping[state->arping_index])
2179 {
2180 char buf[HWADDR_LEN * 3];
2181
2182 hwaddr_ntoa(amsg->sha, ifp->hwlen, buf, sizeof(buf));
2183 if (dhcpcd_selectprofile(ifp, buf) == -1 &&
2184 dhcpcd_selectprofile(ifp, inet_ntoa(amsg->sip)) == -1)
2185 {
2186 /* We didn't find a profile for this
2187 * address or hwaddr, so move to the next
2188 * arping profile */
2189 dhcp_arp_not_found(astate);
2190 return;
2191 }
2192 arp_free(astate);
2193 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
2194 dhcpcd_startinterface(ifp);
2195 return;
2196 }
2197 #else
2198 UNUSED(amsg);
2199 #endif
2200
2201 addr = astate->addr;
2202 arp_free(astate);
2203 dhcp_addr_duplicated(ifp, &addr);
2204 }
2205 #endif
2206
2207 #endif /* ARP */
2208
2209 void
2210 dhcp_bind(struct interface *ifp)
2211 {
2212 struct dhcpcd_ctx *ctx = ifp->ctx;
2213 struct dhcp_state *state = D_STATE(ifp);
2214 struct if_options *ifo = ifp->options;
2215 struct dhcp_lease *lease = &state->lease;
2216 uint8_t old_state;
2217
2218 state->reason = NULL;
2219 /* If we don't have an offer, we are re-binding a lease on preference,
2220 * normally when two interfaces have a lease matching IP addresses. */
2221 if (state->offer) {
2222 free(state->old);
2223 state->old = state->new;
2224 state->old_len = state->new_len;
2225 state->new = state->offer;
2226 state->new_len = state->offer_len;
2227 state->offer = NULL;
2228 state->offer_len = 0;
2229 }
2230 get_lease(ifp, lease, state->new, state->new_len);
2231 if (ifo->options & DHCPCD_STATIC) {
2232 loginfox("%s: using static address %s/%d",
2233 ifp->name, inet_ntoa(lease->addr),
2234 inet_ntocidr(lease->mask));
2235 lease->leasetime = DHCP_INFINITE_LIFETIME;
2236 state->reason = "STATIC";
2237 } else if (ifo->options & DHCPCD_INFORM) {
2238 loginfox("%s: received approval for %s",
2239 ifp->name, inet_ntoa(lease->addr));
2240 lease->leasetime = DHCP_INFINITE_LIFETIME;
2241 state->reason = "INFORM";
2242 } else {
2243 if (lease->frominfo)
2244 state->reason = "TIMEOUT";
2245 if (lease->leasetime == DHCP_INFINITE_LIFETIME) {
2246 lease->renewaltime =
2247 lease->rebindtime =
2248 lease->leasetime;
2249 loginfox("%s: leased %s for infinity",
2250 ifp->name, inet_ntoa(lease->addr));
2251 } else {
2252 if (lease->leasetime < DHCP_MIN_LEASE) {
2253 logwarnx("%s: minimum lease is %d seconds",
2254 ifp->name, DHCP_MIN_LEASE);
2255 lease->leasetime = DHCP_MIN_LEASE;
2256 }
2257 if (lease->rebindtime == 0)
2258 lease->rebindtime =
2259 (uint32_t)(lease->leasetime * T2);
2260 else if (lease->rebindtime >= lease->leasetime) {
2261 lease->rebindtime =
2262 (uint32_t)(lease->leasetime * T2);
2263 logwarnx("%s: rebind time greater than lease "
2264 "time, forcing to %"PRIu32" seconds",
2265 ifp->name, lease->rebindtime);
2266 }
2267 if (lease->renewaltime == 0)
2268 lease->renewaltime =
2269 (uint32_t)(lease->leasetime * T1);
2270 else if (lease->renewaltime > lease->rebindtime) {
2271 lease->renewaltime =
2272 (uint32_t)(lease->leasetime * T1);
2273 logwarnx("%s: renewal time greater than "
2274 "rebind time, forcing to %"PRIu32" seconds",
2275 ifp->name, lease->renewaltime);
2276 }
2277 if (state->state == DHS_RENEW && state->addr &&
2278 lease->addr.s_addr == state->addr->addr.s_addr &&
2279 !(state->added & STATE_FAKE))
2280 logdebugx("%s: leased %s for %"PRIu32" seconds",
2281 ifp->name, inet_ntoa(lease->addr),
2282 lease->leasetime);
2283 else
2284 loginfox("%s: leased %s for %"PRIu32" seconds",
2285 ifp->name, inet_ntoa(lease->addr),
2286 lease->leasetime);
2287 }
2288 }
2289 if (ctx->options & DHCPCD_TEST) {
2290 state->reason = "TEST";
2291 script_runreason(ifp, state->reason);
2292 eloop_exit(ctx->eloop, EXIT_SUCCESS);
2293 return;
2294 }
2295 if (state->reason == NULL) {
2296 if (state->old &&
2297 !(state->added & (STATE_FAKE | STATE_EXPIRED)))
2298 {
2299 if (state->old->yiaddr == state->new->yiaddr &&
2300 lease->server.s_addr &&
2301 state->state != DHS_REBIND)
2302 state->reason = "RENEW";
2303 else
2304 state->reason = "REBIND";
2305 } else if (state->state == DHS_REBOOT)
2306 state->reason = "REBOOT";
2307 else
2308 state->reason = "BOUND";
2309 }
2310 if (lease->leasetime == DHCP_INFINITE_LIFETIME)
2311 lease->renewaltime = lease->rebindtime = lease->leasetime;
2312 else {
2313 eloop_timeout_add_sec(ctx->eloop,
2314 lease->renewaltime, dhcp_startrenew, ifp);
2315 eloop_timeout_add_sec(ctx->eloop,
2316 lease->rebindtime, dhcp_rebind, ifp);
2317 eloop_timeout_add_sec(ctx->eloop,
2318 lease->leasetime, dhcp_expire, ifp);
2319 logdebugx("%s: renew in %"PRIu32" seconds, rebind in %"PRIu32
2320 " seconds",
2321 ifp->name, lease->renewaltime, lease->rebindtime);
2322 }
2323 state->state = DHS_BOUND;
2324 if (!state->lease.frominfo &&
2325 !(ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC))) {
2326 logdebugx("%s: writing lease: %s",
2327 ifp->name, state->leasefile);
2328 if (dhcp_writefile(ifp->ctx, state->leasefile, 0640,
2329 state->new, state->new_len) == -1)
2330 logerr("dhcp_writefile: %s", state->leasefile);
2331 }
2332
2333 old_state = state->added;
2334
2335 if (!(ifo->options & DHCPCD_CONFIGURE)) {
2336 struct ipv4_addr *ia;
2337
2338 script_runreason(ifp, state->reason);
2339 dhcpcd_daemonise(ifp->ctx);
2340
2341 /* We we are not configuring the address, we need to keep
2342 * the BPF socket open if the address does not exist. */
2343 ia = ipv4_iffindaddr(ifp, &state->lease.addr, NULL);
2344 if (ia != NULL) {
2345 state->addr = ia;
2346 state->added = STATE_ADDED;
2347 dhcp_closebpf(ifp);
2348 goto openudp;
2349 }
2350 return;
2351 }
2352
2353 /* Add the address */
2354 if (ipv4_applyaddr(ifp) == NULL) {
2355 /* There was an error adding the address.
2356 * If we are in oneshot, exit with a failure. */
2357 if (ctx->options & DHCPCD_ONESHOT) {
2358 loginfox("exiting due to oneshot");
2359 eloop_exit(ctx->eloop, EXIT_FAILURE);
2360 }
2361 return;
2362 }
2363
2364 /* Close the BPF filter as we can now receive DHCP messages
2365 * on a UDP socket. */
2366 dhcp_closebpf(ifp);
2367
2368 openudp:
2369 /* If not in manager mode, open an address specific socket. */
2370 if (ctx->options & DHCPCD_MANAGER ||
2371 ifo->options & DHCPCD_STATIC ||
2372 (state->old != NULL &&
2373 state->old->yiaddr == state->new->yiaddr &&
2374 old_state & STATE_ADDED && !(old_state & STATE_FAKE)))
2375 return;
2376
2377 dhcp_closeinet(ifp);
2378 #ifdef PRIVSEP
2379 if (IN_PRIVSEP_SE(ctx)) {
2380 if (ps_inet_openbootp(state->addr) == -1)
2381 logerr(__func__);
2382 return;
2383 }
2384 #endif
2385
2386 state->udp_rfd = dhcp_openudp(&state->addr->addr);
2387 if (state->udp_rfd == -1) {
2388 logerr(__func__);
2389 /* Address sharing without manager mode is not supported.
2390 * It's also possible another DHCP client could be running,
2391 * which is even worse.
2392 * We still need to work, so re-open BPF. */
2393 dhcp_openbpf(ifp);
2394 return;
2395 }
2396 if (eloop_event_add(ctx->eloop, state->udp_rfd, ELE_READ,
2397 dhcp_handleifudp, ifp) == -1)
2398 logerr("%s: eloop_event_add", __func__);
2399 }
2400
2401 static size_t
2402 dhcp_message_new(struct bootp **bootp,
2403 const struct in_addr *addr, const struct in_addr *mask)
2404 {
2405 uint8_t *p;
2406 uint32_t cookie;
2407
2408 if ((*bootp = calloc(1, sizeof(**bootp))) == NULL)
2409 return 0;
2410
2411 (*bootp)->yiaddr = addr->s_addr;
2412 p = (*bootp)->vend;
2413
2414 cookie = htonl(MAGIC_COOKIE);
2415 memcpy(p, &cookie, sizeof(cookie));
2416 p += sizeof(cookie);
2417
2418 if (mask->s_addr != INADDR_ANY) {
2419 *p++ = DHO_SUBNETMASK;
2420 *p++ = sizeof(mask->s_addr);
2421 memcpy(p, &mask->s_addr, sizeof(mask->s_addr));
2422 p+= sizeof(mask->s_addr);
2423 }
2424
2425 *p = DHO_END;
2426 return sizeof(**bootp);
2427 }
2428
2429 #if defined(ARP) || defined(KERNEL_RFC5227)
2430 static int
2431 dhcp_arp_address(struct interface *ifp)
2432 {
2433 struct dhcp_state *state;
2434 struct in_addr addr;
2435 struct ipv4_addr *ia;
2436
2437 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
2438
2439 state = D_STATE(ifp);
2440 addr.s_addr = state->offer->yiaddr == INADDR_ANY ?
2441 state->offer->ciaddr : state->offer->yiaddr;
2442 /* If the interface already has the address configured
2443 * then we can't ARP for duplicate detection. */
2444 ia = ipv4_iffindaddr(ifp, &addr, NULL);
2445 #ifdef IN_IFF_NOTUSEABLE
2446 if (ia == NULL || ia->addr_flags & IN_IFF_NOTUSEABLE) {
2447 state->state = DHS_PROBE;
2448 if (ia == NULL) {
2449 struct dhcp_lease l;
2450
2451 get_lease(ifp, &l, state->offer, state->offer_len);
2452 /* Add the address now, let the kernel handle DAD. */
2453 ipv4_addaddr(ifp, &l.addr, &l.mask, &l.brd,
2454 l.leasetime, l.rebindtime);
2455 } else if (ia->addr_flags & IN_IFF_DUPLICATED)
2456 dhcp_addr_duplicated(ifp, &ia->addr);
2457 else
2458 loginfox("%s: waiting for DAD on %s",
2459 ifp->name, inet_ntoa(addr));
2460 return 0;
2461 }
2462 #else
2463 if (!(ifp->flags & IFF_NOARP) &&
2464 ifp->options->options & DHCPCD_ARP)
2465 {
2466 struct arp_state *astate;
2467 struct dhcp_lease l;
2468
2469 /* Even if the address exists, we need to defend it. */
2470 astate = dhcp_arp_new(ifp, &addr);
2471 if (astate == NULL)
2472 return -1;
2473
2474 if (ia == NULL) {
2475 state->state = DHS_PROBE;
2476 get_lease(ifp, &l, state->offer, state->offer_len);
2477 loginfox("%s: probing address %s/%d",
2478 ifp->name, inet_ntoa(l.addr), inet_ntocidr(l.mask));
2479 /* We need to handle DAD. */
2480 arp_probe(astate);
2481 return 0;
2482 }
2483 }
2484 #endif
2485
2486 return 1;
2487 }
2488
2489 static void
2490 dhcp_arp_bind(struct interface *ifp)
2491 {
2492
2493 if (ifp->ctx->options & DHCPCD_TEST ||
2494 dhcp_arp_address(ifp) == 1)
2495 dhcp_bind(ifp);
2496 }
2497 #endif
2498
2499 static void
2500 dhcp_lastlease(void *arg)
2501 {
2502 struct interface *ifp = arg;
2503 struct dhcp_state *state = D_STATE(ifp);
2504
2505 loginfox("%s: timed out contacting a DHCP server, using last lease",
2506 ifp->name);
2507 #if defined(ARP) || defined(KERNEL_RFC5227)
2508 dhcp_arp_bind(ifp);
2509 #else
2510 dhcp_bind(ifp);
2511 #endif
2512 /* Set expired here because dhcp_bind() -> ipv4_addaddr() will reset
2513 * state */
2514 state->added |= STATE_EXPIRED;
2515 state->interval = 0;
2516 dhcp_discover(ifp);
2517 }
2518
2519 static void
2520 dhcp_static(struct interface *ifp)
2521 {
2522 struct if_options *ifo;
2523 struct dhcp_state *state;
2524 struct ipv4_addr *ia;
2525
2526 state = D_STATE(ifp);
2527 ifo = ifp->options;
2528
2529 ia = NULL;
2530 if (ifo->req_addr.s_addr == INADDR_ANY &&
2531 (ia = ipv4_iffindaddr(ifp, NULL, NULL)) == NULL)
2532 {
2533 loginfox("%s: waiting for 3rd party to "
2534 "configure IP address", ifp->name);
2535 state->reason = "3RDPARTY";
2536 script_runreason(ifp, state->reason);
2537 return;
2538 }
2539
2540 state->offer_len = dhcp_message_new(&state->offer,
2541 ia ? &ia->addr : &ifo->req_addr,
2542 ia ? &ia->mask : &ifo->req_mask);
2543 if (state->offer_len)
2544 #if defined(ARP) || defined(KERNEL_RFC5227)
2545 dhcp_arp_bind(ifp);
2546 #else
2547 dhcp_bind(ifp);
2548 #endif
2549 }
2550
2551 void
2552 dhcp_inform(struct interface *ifp)
2553 {
2554 struct dhcp_state *state;
2555 struct if_options *ifo;
2556 struct ipv4_addr *ia;
2557
2558 state = D_STATE(ifp);
2559 ifo = ifp->options;
2560
2561 free(state->offer);
2562 state->offer = NULL;
2563 state->offer_len = 0;
2564
2565 if (ifo->req_addr.s_addr == INADDR_ANY) {
2566 ia = ipv4_iffindaddr(ifp, NULL, NULL);
2567 if (ia == NULL) {
2568 loginfox("%s: waiting for 3rd party to "
2569 "configure IP address",
2570 ifp->name);
2571 if (!(ifp->ctx->options & DHCPCD_TEST)) {
2572 state->reason = "3RDPARTY";
2573 script_runreason(ifp, state->reason);
2574 }
2575 return;
2576 }
2577 } else {
2578 ia = ipv4_iffindaddr(ifp, &ifo->req_addr, &ifo->req_mask);
2579 if (ia == NULL) {
2580 if (ifp->ctx->options & DHCPCD_TEST) {
2581 logerrx("%s: cannot add IP address in test mode",
2582 ifp->name);
2583 return;
2584 }
2585 ia = ipv4_iffindaddr(ifp, &ifo->req_addr, NULL);
2586 if (ia != NULL)
2587 /* Netmask must be different, delete it. */
2588 ipv4_deladdr(ia, 1);
2589 state->offer_len = dhcp_message_new(&state->offer,
2590 &ifo->req_addr, &ifo->req_mask);
2591 #ifdef ARP
2592 if (dhcp_arp_address(ifp) != 1)
2593 return;
2594 #endif
2595 ia = ipv4_iffindaddr(ifp,
2596 &ifo->req_addr, &ifo->req_mask);
2597 assert(ia != NULL);
2598 }
2599 }
2600
2601 state->state = DHS_INFORM;
2602 state->addr = ia;
2603 state->offer_len = dhcp_message_new(&state->offer,
2604 &ia->addr, &ia->mask);
2605 if (state->offer_len) {
2606 dhcp_new_xid(ifp);
2607 get_lease(ifp, &state->lease, state->offer, state->offer_len);
2608 send_inform(ifp);
2609 }
2610 }
2611
2612 void
2613 dhcp_reboot_newopts(struct interface *ifp, unsigned long long oldopts)
2614 {
2615 struct if_options *ifo;
2616 struct dhcp_state *state = D_STATE(ifp);
2617
2618 if (state == NULL || state->state == DHS_NONE)
2619 return;
2620 ifo = ifp->options;
2621 if ((ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC) &&
2622 (state->addr == NULL ||
2623 state->addr->addr.s_addr != ifo->req_addr.s_addr)) ||
2624 (oldopts & (DHCPCD_INFORM | DHCPCD_STATIC) &&
2625 !(ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC))))
2626 {
2627 dhcp_drop(ifp, "EXPIRE");
2628 }
2629 }
2630
2631 #ifdef ARP
2632 static int
2633 dhcp_activeaddr(const struct interface *ifp, const struct in_addr *addr)
2634 {
2635 const struct interface *ifp1;
2636 const struct dhcp_state *state;
2637
2638 TAILQ_FOREACH(ifp1, ifp->ctx->ifaces, next) {
2639 if (ifp1 == ifp)
2640 continue;
2641 if ((state = D_CSTATE(ifp1)) == NULL)
2642 continue;
2643 switch(state->state) {
2644 case DHS_REBOOT:
2645 case DHS_RENEW:
2646 case DHS_REBIND:
2647 case DHS_BOUND:
2648 case DHS_INFORM:
2649 break;
2650 default:
2651 continue;
2652 }
2653 if (state->lease.addr.s_addr == addr->s_addr)
2654 return 1;
2655 }
2656 return 0;
2657 }
2658 #endif
2659
2660 static void
2661 dhcp_reboot(struct interface *ifp)
2662 {
2663 struct if_options *ifo;
2664 struct dhcp_state *state = D_STATE(ifp);
2665 #ifdef ARP
2666 struct ipv4_addr *ia;
2667 #endif
2668
2669 if (state == NULL || state->state == DHS_NONE)
2670 return;
2671 ifo = ifp->options;
2672 state->state = DHS_REBOOT;
2673 state->interval = 0;
2674
2675 if (ifo->options & DHCPCD_LINK && !if_is_link_up(ifp)) {
2676 loginfox("%s: waiting for carrier", ifp->name);
2677 return;
2678 }
2679 if (ifo->options & DHCPCD_STATIC) {
2680 dhcp_static(ifp);
2681 return;
2682 }
2683 if (ifo->options & DHCPCD_INFORM) {
2684 loginfox("%s: informing address of %s",
2685 ifp->name, inet_ntoa(state->lease.addr));
2686 dhcp_inform(ifp);
2687 return;
2688 }
2689 if (ifo->reboot == 0 || state->offer == NULL) {
2690 dhcp_discover(ifp);
2691 return;
2692 }
2693 if (!IS_DHCP(state->offer))
2694 return;
2695
2696 loginfox("%s: rebinding lease of %s",
2697 ifp->name, inet_ntoa(state->lease.addr));
2698
2699 #ifdef ARP
2700 #ifndef KERNEL_RFC5227
2701 /* Create the DHCP ARP state so we can defend it. */
2702 (void)dhcp_arp_new(ifp, &state->lease.addr);
2703 #endif
2704
2705 /* If the address exists on the interface and no other interface
2706 * is currently using it then announce it to ensure this
2707 * interface gets the reply. */
2708 ia = ipv4_iffindaddr(ifp, &state->lease.addr, NULL);
2709 if (ia != NULL &&
2710 !(ifp->ctx->options & DHCPCD_TEST) &&
2711 #ifdef IN_IFF_NOTUSEABLE
2712 !(ia->addr_flags & IN_IFF_NOTUSEABLE) &&
2713 #endif
2714 dhcp_activeaddr(ifp, &state->lease.addr) == 0)
2715 arp_ifannounceaddr(ifp, &state->lease.addr);
2716 #endif
2717
2718 dhcp_new_xid(ifp);
2719 state->lease.server.s_addr = INADDR_ANY;
2720 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
2721
2722 #ifdef IPV4LL
2723 /* Need to add this before dhcp_expire and friends. */
2724 if (!ifo->fallback && ifo->options & DHCPCD_IPV4LL)
2725 eloop_timeout_add_sec(ifp->ctx->eloop,
2726 ifo->reboot, ipv4ll_start, ifp);
2727 #endif
2728
2729 if (ifo->options & DHCPCD_LASTLEASE && state->lease.frominfo)
2730 eloop_timeout_add_sec(ifp->ctx->eloop,
2731 ifo->reboot, dhcp_lastlease, ifp);
2732 else if (!(ifo->options & DHCPCD_INFORM))
2733 eloop_timeout_add_sec(ifp->ctx->eloop,
2734 ifo->reboot, dhcp_expire, ifp);
2735
2736 /* Don't bother ARP checking as the server could NAK us first.
2737 * Don't call dhcp_request as that would change the state */
2738 send_request(ifp);
2739 }
2740
2741 void
2742 dhcp_drop(struct interface *ifp, const char *reason)
2743 {
2744 struct dhcp_state *state = D_STATE(ifp);
2745
2746 /* dhcp_start may just have been called and we don't yet have a state
2747 * but we do have a timeout, so punt it. */
2748 if (state == NULL || state->state == DHS_NONE) {
2749 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
2750 return;
2751 }
2752
2753 #ifdef ARP
2754 if (state->addr != NULL)
2755 arp_freeaddr(ifp, &state->addr->addr);
2756 #endif
2757 #ifdef ARPING
2758 state->arping_index = -1;
2759 #endif
2760
2761 if (ifp->options->options & DHCPCD_RELEASE &&
2762 !(ifp->options->options & DHCPCD_INFORM))
2763 {
2764 /* Failure to send the release may cause this function to
2765 * re-enter so guard by setting the state. */
2766 if (state->state == DHS_RELEASE)
2767 return;
2768 state->state = DHS_RELEASE;
2769
2770 dhcp_unlink(ifp->ctx, state->leasefile);
2771 if (if_is_link_up(ifp) &&
2772 state->new != NULL &&
2773 state->lease.server.s_addr != INADDR_ANY)
2774 {
2775 loginfox("%s: releasing lease of %s",
2776 ifp->name, inet_ntoa(state->lease.addr));
2777 dhcp_new_xid(ifp);
2778 send_message(ifp, DHCP_RELEASE, NULL);
2779 }
2780 }
2781 #ifdef AUTH
2782 else if (state->auth.reconf != NULL) {
2783 /*
2784 * Drop the lease as the token may only be present
2785 * in the initial reply message and not subsequent
2786 * renewals.
2787 * If dhcpcd is restarted, the token is lost.
2788 * XXX persist this in another file?
2789 */
2790 dhcp_unlink(ifp->ctx, state->leasefile);
2791 }
2792 #endif
2793
2794 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
2795 #ifdef AUTH
2796 dhcp_auth_reset(&state->auth);
2797 #endif
2798
2799 state->state = DHS_NONE;
2800 free(state->offer);
2801 state->offer = NULL;
2802 state->offer_len = 0;
2803 free(state->old);
2804 state->old = state->new;
2805 state->old_len = state->new_len;
2806 state->new = NULL;
2807 state->new_len = 0;
2808 state->reason = reason;
2809 if (ifp->options->options & DHCPCD_CONFIGURE)
2810 ipv4_applyaddr(ifp);
2811 else {
2812 state->addr = NULL;
2813 state->added = 0;
2814 script_runreason(ifp, state->reason);
2815 }
2816 free(state->old);
2817 state->old = NULL;
2818 state->old_len = 0;
2819 state->lease.addr.s_addr = 0;
2820 ifp->options->options &= ~(DHCPCD_CSR_WARNED |
2821 DHCPCD_ROUTER_HOST_ROUTE_WARNED);
2822
2823 /* Close DHCP ports so a changed interface family is picked
2824 * up by a new BPF state. */
2825 dhcp_close(ifp);
2826 }
2827
2828 static int
2829 blacklisted_ip(const struct if_options *ifo, in_addr_t addr)
2830 {
2831 size_t i;
2832
2833 for (i = 0; i < ifo->blacklist_len; i += 2)
2834 if (ifo->blacklist[i] == (addr & ifo->blacklist[i + 1]))
2835 return 1;
2836 return 0;
2837 }
2838
2839 #define WHTLST_NONE 0
2840 #define WHTLST_MATCH 1
2841 #define WHTLST_NOMATCH 2
2842 static unsigned int
2843 whitelisted_ip(const struct if_options *ifo, in_addr_t addr)
2844 {
2845 size_t i;
2846
2847 if (ifo->whitelist_len == 0)
2848 return WHTLST_NONE;
2849 for (i = 0; i < ifo->whitelist_len; i += 2)
2850 if (ifo->whitelist[i] == (addr & ifo->whitelist[i + 1]))
2851 return WHTLST_MATCH;
2852 return WHTLST_NOMATCH;
2853 }
2854
2855 static void
2856 log_dhcp(int loglevel, const char *msg,
2857 const struct interface *ifp, const struct bootp *bootp, size_t bootp_len,
2858 const struct in_addr *from, int ad)
2859 {
2860 const char *tfrom;
2861 char *a, sname[sizeof(bootp->sname) * 4];
2862 struct in_addr addr;
2863 int r;
2864 uint8_t overl;
2865
2866 if (strcmp(msg, "NAK:") == 0) {
2867 a = get_option_string(ifp->ctx, bootp, bootp_len, DHO_MESSAGE);
2868 if (a) {
2869 char *tmp;
2870 size_t al, tmpl;
2871
2872 al = strlen(a);
2873 tmpl = (al * 4) + 1;
2874 tmp = malloc(tmpl);
2875 if (tmp == NULL) {
2876 logerr(__func__);
2877 free(a);
2878 return;
2879 }
2880 print_string(tmp, tmpl, OT_STRING, (uint8_t *)a, al);
2881 free(a);
2882 a = tmp;
2883 }
2884 } else if (ad && bootp->yiaddr != 0) {
2885 addr.s_addr = bootp->yiaddr;
2886 a = strdup(inet_ntoa(addr));
2887 if (a == NULL) {
2888 logerr(__func__);
2889 return;
2890 }
2891 } else
2892 a = NULL;
2893
2894 tfrom = "from";
2895 r = get_option_addr(ifp->ctx, &addr, bootp, bootp_len, DHO_SERVERID);
2896 if (get_option_uint8(ifp->ctx, &overl, bootp, bootp_len,
2897 DHO_OPTSOVERLOADED) == -1)
2898 overl = 0;
2899 if (bootp->sname[0] && r == 0 && !(overl & 2)) {
2900 print_string(sname, sizeof(sname), OT_STRING | OT_DOMAIN,
2901 bootp->sname, sizeof(bootp->sname));
2902 if (a == NULL)
2903 logmessage(loglevel, "%s: %s %s %s %s",
2904 ifp->name, msg, tfrom, inet_ntoa(addr), sname);
2905 else
2906 logmessage(loglevel, "%s: %s %s %s %s %s",
2907 ifp->name, msg, a, tfrom, inet_ntoa(addr), sname);
2908 } else {
2909 if (r != 0) {
2910 tfrom = "via";
2911 addr = *from;
2912 }
2913 if (a == NULL)
2914 logmessage(loglevel, "%s: %s %s %s",
2915 ifp->name, msg, tfrom, inet_ntoa(addr));
2916 else
2917 logmessage(loglevel, "%s: %s %s %s %s",
2918 ifp->name, msg, a, tfrom, inet_ntoa(addr));
2919 }
2920 free(a);
2921 }
2922
2923 /* If we're sharing the same IP address with another interface on the
2924 * same network, we may receive the DHCP reply on the wrong interface.
2925 * Try and re-direct it here. */
2926 static void
2927 dhcp_redirect_dhcp(struct interface *ifp, struct bootp *bootp, size_t bootp_len,
2928 const struct in_addr *from)
2929 {
2930 struct interface *ifn;
2931 const struct dhcp_state *state;
2932 uint32_t xid;
2933
2934 xid = ntohl(bootp->xid);
2935 TAILQ_FOREACH(ifn, ifp->ctx->ifaces, next) {
2936 if (ifn == ifp)
2937 continue;
2938 state = D_CSTATE(ifn);
2939 if (state == NULL || state->state == DHS_NONE)
2940 continue;
2941 if (state->xid != xid)
2942 continue;
2943 if (ifn->hwlen <= sizeof(bootp->chaddr) &&
2944 memcmp(bootp->chaddr, ifn->hwaddr, ifn->hwlen))
2945 continue;
2946 logdebugx("%s: redirecting DHCP message to %s",
2947 ifp->name, ifn->name);
2948 dhcp_handledhcp(ifn, bootp, bootp_len, from);
2949 }
2950 }
2951
2952 static void
2953 dhcp_handledhcp(struct interface *ifp, struct bootp *bootp, size_t bootp_len,
2954 const struct in_addr *from)
2955 {
2956 struct dhcp_state *state = D_STATE(ifp);
2957 struct if_options *ifo = ifp->options;
2958 struct dhcp_lease *lease = &state->lease;
2959 uint8_t type, tmp;
2960 struct in_addr addr;
2961 unsigned int i;
2962 char *msg;
2963 bool bootp_copied;
2964 uint32_t v6only_time = 0;
2965 bool use_v6only = false;
2966 #ifdef AUTH
2967 const uint8_t *auth;
2968 size_t auth_len;
2969 #endif
2970 #ifdef IN_IFF_DUPLICATED
2971 struct ipv4_addr *ia;
2972 #endif
2973
2974 #define LOGDHCP0(l, m) \
2975 log_dhcp((l), (m), ifp, bootp, bootp_len, from, 0)
2976 #define LOGDHCP(l, m) \
2977 log_dhcp((l), (m), ifp, bootp, bootp_len, from, 1)
2978
2979 #define IS_STATE_ACTIVE(s) ((s)-state != DHS_NONE && \
2980 (s)->state != DHS_INIT && (s)->state != DHS_BOUND)
2981
2982 if (bootp->op != BOOTREPLY) {
2983 if (IS_STATE_ACTIVE(state))
2984 logdebugx("%s: op (%d) is not BOOTREPLY",
2985 ifp->name, bootp->op);
2986 return;
2987 }
2988
2989 if (state->xid != ntohl(bootp->xid)) {
2990 if (IS_STATE_ACTIVE(state))
2991 logdebugx("%s: wrong xid 0x%x (expecting 0x%x) from %s",
2992 ifp->name, ntohl(bootp->xid), state->xid,
2993 inet_ntoa(*from));
2994 dhcp_redirect_dhcp(ifp, bootp, bootp_len, from);
2995 return;
2996 }
2997
2998 if (ifp->hwlen <= sizeof(bootp->chaddr) &&
2999 memcmp(bootp->chaddr, ifp->hwaddr, ifp->hwlen))
3000 {
3001 if (IS_STATE_ACTIVE(state)) {
3002 char buf[sizeof(bootp->chaddr) * 3];
3003
3004 logdebugx("%s: xid 0x%x is for hwaddr %s",
3005 ifp->name, ntohl(bootp->xid),
3006 hwaddr_ntoa(bootp->chaddr, sizeof(bootp->chaddr),
3007 buf, sizeof(buf)));
3008 }
3009 dhcp_redirect_dhcp(ifp, bootp, bootp_len, from);
3010 return;
3011 }
3012
3013 if (!ifp->active)
3014 return;
3015
3016 i = whitelisted_ip(ifp->options, from->s_addr);
3017 switch (i) {
3018 case WHTLST_NOMATCH:
3019 logwarnx("%s: non whitelisted DHCP packet from %s",
3020 ifp->name, inet_ntoa(*from));
3021 return;
3022 case WHTLST_MATCH:
3023 break;
3024 case WHTLST_NONE:
3025 if (blacklisted_ip(ifp->options, from->s_addr) == 1) {
3026 logwarnx("%s: blacklisted DHCP packet from %s",
3027 ifp->name, inet_ntoa(*from));
3028 return;
3029 }
3030 }
3031
3032 /* We may have found a BOOTP server */
3033 if (get_option_uint8(ifp->ctx, &type,
3034 bootp, bootp_len, DHO_MESSAGETYPE) == -1)
3035 type = 0;
3036 else if (ifo->options & DHCPCD_BOOTP) {
3037 logdebugx("%s: ignoring DHCP reply (expecting BOOTP)",
3038 ifp->name);
3039 return;
3040 }
3041
3042 #ifdef AUTH
3043 /* Authenticate the message */
3044 auth = get_option(ifp->ctx, bootp, bootp_len,
3045 DHO_AUTHENTICATION, &auth_len);
3046 if (auth) {
3047 if (dhcp_auth_validate(&state->auth, &ifo->auth,
3048 (uint8_t *)bootp, bootp_len, 4, type,
3049 auth, auth_len) == NULL)
3050 {
3051 LOGDHCP0(LOG_ERR, "authentication failed");
3052 return;
3053 }
3054 if (state->auth.token)
3055 logdebugx("%s: validated using 0x%08" PRIu32,
3056 ifp->name, state->auth.token->secretid);
3057 else
3058 loginfox("%s: accepted reconfigure key", ifp->name);
3059 } else if (ifo->auth.options & DHCPCD_AUTH_SEND) {
3060 if (ifo->auth.options & DHCPCD_AUTH_REQUIRE) {
3061 LOGDHCP0(LOG_ERR, "no authentication");
3062 return;
3063 }
3064 LOGDHCP0(LOG_WARNING, "no authentication");
3065 }
3066 #endif
3067
3068 /* RFC 3203 */
3069 if (type == DHCP_FORCERENEW) {
3070 if (from->s_addr == INADDR_ANY ||
3071 from->s_addr == INADDR_BROADCAST)
3072 {
3073 LOGDHCP(LOG_ERR, "discarding Force Renew");
3074 return;
3075 }
3076 #ifdef AUTH
3077 if (auth == NULL) {
3078 LOGDHCP(LOG_ERR, "unauthenticated Force Renew");
3079 if (ifo->auth.options & DHCPCD_AUTH_REQUIRE)
3080 return;
3081 }
3082 if (state->state != DHS_BOUND && state->state != DHS_INFORM) {
3083 LOGDHCP(LOG_DEBUG, "not bound, ignoring Force Renew");
3084 return;
3085 }
3086 LOGDHCP(LOG_INFO, "Force Renew from");
3087 /* The rebind and expire timings are still the same, we just
3088 * enter the renew state early */
3089 if (state->state == DHS_BOUND)
3090 dhcp_renew(ifp);
3091 else {
3092 eloop_timeout_delete(ifp->ctx->eloop,
3093 send_inform, ifp);
3094 dhcp_inform(ifp);
3095 }
3096 #else
3097 LOGDHCP(LOG_ERR, "unauthenticated Force Renew");
3098 #endif
3099 return;
3100 }
3101
3102 if (state->state == DHS_BOUND) {
3103 LOGDHCP(LOG_DEBUG, "bound, ignoring");
3104 return;
3105 }
3106
3107 if (state->state == DHS_PROBE) {
3108 /* Ignore any DHCP messages whilst probing a lease to bind. */
3109 LOGDHCP(LOG_DEBUG, "probing, ignoring");
3110 return;
3111 }
3112
3113 /* reset the message counter */
3114 state->interval = 0;
3115
3116 /* Ensure that no reject options are present */
3117 for (i = 1; i < 255; i++) {
3118 if (has_option_mask(ifo->rejectmask, i) &&
3119 get_option_uint8(ifp->ctx, &tmp,
3120 bootp, bootp_len, (uint8_t)i) == 0)
3121 {
3122 LOGDHCP(LOG_WARNING, "reject DHCP");
3123 return;
3124 }
3125 }
3126
3127 if (type == DHCP_NAK) {
3128 /* For NAK, only check if we require the ServerID */
3129 if (has_option_mask(ifo->requiremask, DHO_SERVERID) &&
3130 get_option_addr(ifp->ctx, &addr,
3131 bootp, bootp_len, DHO_SERVERID) == -1)
3132 {
3133 LOGDHCP(LOG_WARNING, "reject NAK");
3134 return;
3135 }
3136
3137 /* We should restart on a NAK */
3138 LOGDHCP(LOG_WARNING, "NAK:");
3139 if ((msg = get_option_string(ifp->ctx,
3140 bootp, bootp_len, DHO_MESSAGE)))
3141 {
3142 logwarnx("%s: message: %s", ifp->name, msg);
3143 free(msg);
3144 }
3145 if (state->state == DHS_INFORM) /* INFORM should not be NAKed */
3146 return;
3147 if (!(ifp->ctx->options & DHCPCD_TEST)) {
3148 dhcp_drop(ifp, "NAK");
3149 dhcp_unlink(ifp->ctx, state->leasefile);
3150 }
3151
3152 /* If we constantly get NAKS then we should slowly back off */
3153 eloop_timeout_add_sec(ifp->ctx->eloop,
3154 state->nakoff, dhcp_discover, ifp);
3155 if (state->nakoff == 0)
3156 state->nakoff = 1;
3157 else {
3158 state->nakoff *= 2;
3159 if (state->nakoff > NAKOFF_MAX)
3160 state->nakoff = NAKOFF_MAX;
3161 }
3162 return;
3163 }
3164
3165 /* Ensure that all required options are present */
3166 for (i = 1; i < 255; i++) {
3167 if (has_option_mask(ifo->requiremask, i) &&
3168 get_option_uint8(ifp->ctx, &tmp,
3169 bootp, bootp_len, (uint8_t)i) != 0)
3170 {
3171 /* If we are BOOTP, then ignore the need for serverid.
3172 * To ignore BOOTP, require dhcp_message_type.
3173 * However, nothing really stops BOOTP from providing
3174 * DHCP style options as well so the above isn't
3175 * always true. */
3176 if (type == 0 && i == DHO_SERVERID)
3177 continue;
3178 LOGDHCP(LOG_WARNING, "reject DHCP");
3179 return;
3180 }
3181 }
3182
3183 if (has_option_mask(ifo->requestmask, DHO_IPV6_PREFERRED_ONLY)) {
3184 if (get_option_uint32(ifp->ctx, &v6only_time, bootp, bootp_len,
3185 DHO_IPV6_PREFERRED_ONLY) == 0 &&
3186 (state->state == DHS_DISCOVER || state->state == DHS_REBOOT))
3187 {
3188 char v6msg[128];
3189
3190 use_v6only = true;
3191 if (v6only_time < MIN_V6ONLY_WAIT)
3192 v6only_time = MIN_V6ONLY_WAIT;
3193 snprintf(v6msg, sizeof(v6msg),
3194 "IPv6-Only Preferred received (%u seconds)",
3195 v6only_time);
3196 LOGDHCP(LOG_INFO, v6msg);
3197 }
3198 }
3199
3200 /* DHCP Auto-Configure, RFC 2563 */
3201 if (type == DHCP_OFFER && bootp->yiaddr == 0) {
3202 LOGDHCP(LOG_WARNING, "no address given");
3203 if ((msg = get_option_string(ifp->ctx,
3204 bootp, bootp_len, DHO_MESSAGE)))
3205 {
3206 logwarnx("%s: message: %s", ifp->name, msg);
3207 free(msg);
3208 }
3209 #ifdef IPV4LL
3210 if (state->state == DHS_DISCOVER &&
3211 get_option_uint8(ifp->ctx, &tmp, bootp, bootp_len,
3212 DHO_AUTOCONFIGURE) == 0)
3213 {
3214 switch (tmp) {
3215 case 0:
3216 LOGDHCP(LOG_WARNING, "IPv4LL disabled from");
3217 ipv4ll_drop(ifp);
3218 #ifdef ARP
3219 arp_drop(ifp);
3220 #endif
3221 break;
3222 case 1:
3223 LOGDHCP(LOG_WARNING, "IPv4LL enabled from");
3224 ipv4ll_start(ifp);
3225 break;
3226 default:
3227 logerrx("%s: unknown auto configuration "
3228 "option %d",
3229 ifp->name, tmp);
3230 break;
3231 }
3232 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
3233 eloop_timeout_add_sec(ifp->ctx->eloop,
3234 use_v6only ? v6only_time : DHCP_MAX,
3235 dhcp_discover, ifp);
3236 }
3237 #endif
3238 return;
3239 }
3240
3241 if (use_v6only) {
3242 dhcp_drop(ifp, "EXPIRE");
3243 dhcp_unlink(ifp->ctx, state->leasefile);
3244 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
3245 eloop_timeout_add_sec(ifp->ctx->eloop, v6only_time,
3246 dhcp_discover, ifp);
3247 return;
3248 }
3249
3250 /* Ensure that the address offered is valid */
3251 if ((type == 0 || type == DHCP_OFFER || type == DHCP_ACK) &&
3252 (bootp->ciaddr == INADDR_ANY || bootp->ciaddr == INADDR_BROADCAST)
3253 &&
3254 (bootp->yiaddr == INADDR_ANY || bootp->yiaddr == INADDR_BROADCAST))
3255 {
3256 LOGDHCP(LOG_WARNING, "reject invalid address");
3257 return;
3258 }
3259
3260 #ifdef IN_IFF_DUPLICATED
3261 ia = ipv4_iffindaddr(ifp, &lease->addr, NULL);
3262 if (ia && ia->addr_flags & IN_IFF_DUPLICATED) {
3263 LOGDHCP(LOG_WARNING, "declined duplicate address");
3264 if (type)
3265 dhcp_decline(ifp);
3266 ipv4_deladdr(ia, 0);
3267 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
3268 eloop_timeout_add_sec(ifp->ctx->eloop,
3269 DHCP_RAND_MAX, dhcp_discover, ifp);
3270 return;
3271 }
3272 #endif
3273
3274 bootp_copied = false;
3275 if ((type == 0 || type == DHCP_OFFER) && state->state == DHS_DISCOVER) {
3276 lease->frominfo = 0;
3277 lease->addr.s_addr = bootp->yiaddr;
3278 memcpy(&lease->cookie, bootp->vend, sizeof(lease->cookie));
3279 if (type == 0 ||
3280 get_option_addr(ifp->ctx,
3281 &lease->server, bootp, bootp_len, DHO_SERVERID) != 0)
3282 lease->server.s_addr = INADDR_ANY;
3283
3284 /* Test for rapid commit in the OFFER */
3285 if (!(ifp->ctx->options & DHCPCD_TEST) &&
3286 has_option_mask(ifo->requestmask, DHO_RAPIDCOMMIT) &&
3287 get_option(ifp->ctx, bootp, bootp_len,
3288 DHO_RAPIDCOMMIT, NULL))
3289 {
3290 state->state = DHS_REQUEST;
3291 goto rapidcommit;
3292 }
3293
3294 LOGDHCP(LOG_INFO, "offered");
3295 if (state->offer_len < bootp_len) {
3296 free(state->offer);
3297 if ((state->offer = malloc(bootp_len)) == NULL) {
3298 logerr(__func__);
3299 state->offer_len = 0;
3300 return;
3301 }
3302 }
3303 state->offer_len = bootp_len;
3304 memcpy(state->offer, bootp, bootp_len);
3305 bootp_copied = true;
3306 if (ifp->ctx->options & DHCPCD_TEST) {
3307 free(state->old);
3308 state->old = state->new;
3309 state->old_len = state->new_len;
3310 state->new = state->offer;
3311 state->new_len = state->offer_len;
3312 state->offer = NULL;
3313 state->offer_len = 0;
3314 state->reason = "TEST";
3315 script_runreason(ifp, state->reason);
3316 eloop_exit(ifp->ctx->eloop, EXIT_SUCCESS);
3317 state->bpf->bpf_flags |= BPF_EOF;
3318 return;
3319 }
3320 eloop_timeout_delete(ifp->ctx->eloop, send_discover, ifp);
3321 /* We don't request BOOTP addresses */
3322 if (type) {
3323 /* We used to ARP check here, but that seems to be in
3324 * violation of RFC2131 where it only describes
3325 * DECLINE after REQUEST.
3326 * It also seems that some MS DHCP servers actually
3327 * ignore DECLINE if no REQUEST, ie we decline a
3328 * DISCOVER. */
3329 dhcp_request(ifp);
3330 return;
3331 }
3332 }
3333
3334 if (type) {
3335 if (type == DHCP_OFFER) {
3336 LOGDHCP(LOG_WARNING, "ignoring offer of");
3337 return;
3338 }
3339
3340 /* We should only be dealing with acks */
3341 if (type != DHCP_ACK) {
3342 LOGDHCP(LOG_ERR, "not ACK or OFFER");
3343 return;
3344 }
3345
3346 if (state->state == DHS_DISCOVER) {
3347 /* We only allow ACK of rapid commit DISCOVER. */
3348 if (has_option_mask(ifo->requestmask,
3349 DHO_RAPIDCOMMIT) &&
3350 get_option(ifp->ctx, bootp, bootp_len,
3351 DHO_RAPIDCOMMIT, NULL))
3352 state->state = DHS_REQUEST;
3353 else {
3354 LOGDHCP(LOG_DEBUG, "ignoring ack of");
3355 return;
3356 }
3357 }
3358
3359 rapidcommit:
3360 if (!(ifo->options & DHCPCD_INFORM))
3361 LOGDHCP(LOG_DEBUG, "acknowledged");
3362 else
3363 ifo->options &= ~DHCPCD_STATIC;
3364 }
3365
3366 /* No NAK, so reset the backoff
3367 * We don't reset on an OFFER message because the server could
3368 * potentially NAK the REQUEST. */
3369 state->nakoff = 0;
3370
3371 /* BOOTP could have already assigned this above. */
3372 if (!bootp_copied) {
3373 if (state->offer_len < bootp_len) {
3374 free(state->offer);
3375 if ((state->offer = malloc(bootp_len)) == NULL) {
3376 logerr(__func__);
3377 state->offer_len = 0;
3378 return;
3379 }
3380 }
3381 state->offer_len = bootp_len;
3382 memcpy(state->offer, bootp, bootp_len);
3383 }
3384
3385 lease->frominfo = 0;
3386 eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
3387
3388 #if defined(ARP) || defined(KERNEL_RFC5227)
3389 dhcp_arp_bind(ifp);
3390 #else
3391 dhcp_bind(ifp);
3392 #endif
3393 }
3394
3395 static void *
3396 get_udp_data(void *packet, size_t *len)
3397 {
3398 const struct ip *ip = packet;
3399 size_t ip_hl = (size_t)ip->ip_hl * 4;
3400 char *p = packet;
3401
3402 p += ip_hl + sizeof(struct udphdr);
3403 *len = (size_t)ntohs(ip->ip_len) - sizeof(struct udphdr) - ip_hl;
3404 return p;
3405 }
3406
3407 static bool
3408 is_packet_udp_bootp(void *packet, size_t plen)
3409 {
3410 struct ip *ip = packet;
3411 size_t ip_hlen;
3412 struct udphdr udp;
3413
3414 if (plen < sizeof(*ip))
3415 return false;
3416
3417 if (ip->ip_v != IPVERSION || ip->ip_p != IPPROTO_UDP)
3418 return false;
3419
3420 /* Sanity. */
3421 if (ntohs(ip->ip_len) > plen)
3422 return false;
3423
3424 ip_hlen = (size_t)ip->ip_hl * 4;
3425 if (ip_hlen < sizeof(*ip))
3426 return false;
3427
3428 /* Check we have a UDP header and BOOTP. */
3429 if (ip_hlen + sizeof(udp) + offsetof(struct bootp, vend) > plen)
3430 return false;
3431
3432 /* Sanity. */
3433 memcpy(&udp, (char *)ip + ip_hlen, sizeof(udp));
3434 if (ntohs(udp.uh_ulen) < sizeof(udp))
3435 return false;
3436 if (ip_hlen + ntohs(udp.uh_ulen) > plen)
3437 return false;
3438
3439 /* Check it's to the right port. */
3440 if (udp.uh_dport != htons(BOOTPC))
3441 return false;
3442
3443 return true;
3444 }
3445
3446 /* Lengths have already been checked. */
3447 static bool
3448 checksums_valid(void *packet,
3449 struct in_addr *from, unsigned int flags)
3450 {
3451 struct ip *ip = packet;
3452 union pip {
3453 struct ip ip;
3454 uint16_t w[sizeof(struct ip) / 2];
3455 } pip = {
3456 .ip = {
3457 .ip_p = IPPROTO_UDP,
3458 .ip_src = ip->ip_src,
3459 .ip_dst = ip->ip_dst,
3460 }
3461 };
3462 size_t ip_hlen;
3463 struct udphdr udp;
3464 char *udpp, *uh_sump;
3465 uint32_t csum;
3466
3467 if (from != NULL)
3468 from->s_addr = ip->ip_src.s_addr;
3469
3470 ip_hlen = (size_t)ip->ip_hl * 4;
3471 if (in_cksum(ip, ip_hlen, NULL) != 0)
3472 return false;
3473
3474 if (flags & BPF_PARTIALCSUM)
3475 return true;
3476
3477 udpp = (char *)ip + ip_hlen;
3478 memcpy(&udp, udpp, sizeof(udp));
3479 if (udp.uh_sum == 0)
3480 return true;
3481
3482 /* UDP checksum is based on a pseudo IP header alongside
3483 * the UDP header and payload. */
3484 pip.ip.ip_len = udp.uh_ulen;
3485 csum = 0;
3486
3487 /* Need to zero the UDP sum in the packet for the checksum to work. */
3488 uh_sump = udpp + offsetof(struct udphdr, uh_sum);
3489 memset(uh_sump, 0, sizeof(udp.uh_sum));
3490
3491 /* Checksum pseudo header and then UDP + payload. */
3492 in_cksum(pip.w, sizeof(pip.w), &csum);
3493 csum = in_cksum(udpp, ntohs(udp.uh_ulen), &csum);
3494
3495 #if 0 /* Not needed, just here for completeness. */
3496 /* Put the checksum back. */
3497 memcpy(uh_sump, &udp.uh_sum, sizeof(udp.uh_sum));
3498 #endif
3499
3500 return csum == udp.uh_sum;
3501 }
3502
3503 static void
3504 dhcp_handlebootp(struct interface *ifp, struct bootp *bootp, size_t len,
3505 struct in_addr *from)
3506 {
3507 size_t v;
3508
3509 if (len < offsetof(struct bootp, vend)) {
3510 logerrx("%s: truncated packet (%zu) from %s",
3511 ifp->name, len, inet_ntoa(*from));
3512 return;
3513 }
3514
3515 /* Unlikely, but appeases sanitizers. */
3516 if (len > FRAMELEN_MAX) {
3517 logerrx("%s: packet exceeded frame length (%zu) from %s",
3518 ifp->name, len, inet_ntoa(*from));
3519 return;
3520 }
3521
3522 /* To make our IS_DHCP macro easy, ensure the vendor
3523 * area has at least 4 octets. */
3524 v = len - offsetof(struct bootp, vend);
3525 while (v < 4) {
3526 bootp->vend[v++] = '\0';
3527 len++;
3528 }
3529
3530 dhcp_handledhcp(ifp, bootp, len, from);
3531 }
3532
3533 void
3534 dhcp_packet(struct interface *ifp, uint8_t *data, size_t len,
3535 unsigned int bpf_flags)
3536 {
3537 struct bootp *bootp;
3538 struct in_addr from;
3539 size_t udp_len;
3540 size_t fl = bpf_frame_header_len(ifp);
3541 #ifdef PRIVSEP
3542 const struct dhcp_state *state = D_CSTATE(ifp);
3543
3544 /* It's possible that an interface departs and arrives in short
3545 * order to receive a BPF frame out of order.
3546 * There is a similar check in ARP, but much lower down the stack.
3547 * It's not needed for other inet protocols because we send the
3548 * message as a whole and select the interface off that and then
3549 * check state. BPF on the other hand is very interface
3550 * specific and we do need this check. */
3551 if (state == NULL)
3552 return;
3553
3554 /* Ignore double reads */
3555 if (IN_PRIVSEP(ifp->ctx)) {
3556 switch (state->state) {
3557 case DHS_BOUND: /* FALLTHROUGH */
3558 case DHS_RENEW:
3559 return;
3560 default:
3561 break;
3562 }
3563 }
3564 #endif
3565
3566 /* Trim frame header */
3567 if (fl != 0) {
3568 if (len < fl) {
3569 logerrx("%s: %s: short frame header %zu",
3570 __func__, ifp->name, len);
3571 return;
3572 }
3573 len -= fl;
3574 /* Move the data to avoid alignment errors. */
3575 memmove(data, data + fl, len);
3576 }
3577
3578 /* Validate filter. */
3579 if (!is_packet_udp_bootp(data, len)) {
3580 #ifdef BPF_DEBUG
3581 logerrx("%s: DHCP BPF validation failure", ifp->name);
3582 #endif
3583 return;
3584 }
3585
3586 if (!checksums_valid(data, &from, bpf_flags)) {
3587 logerrx("%s: checksum failure from %s",
3588 ifp->name, inet_ntoa(from));
3589 return;
3590 }
3591
3592 /*
3593 * DHCP has a variable option area rather than a fixed vendor area.
3594 * Because DHCP uses the BOOTP protocol it should still send BOOTP
3595 * sized packets to be RFC compliant.
3596 * However some servers send a truncated vendor area.
3597 * dhcpcd can work fine without the vendor area being sent.
3598 */
3599 bootp = get_udp_data(data, &udp_len);
3600 dhcp_handlebootp(ifp, bootp, udp_len, &from);
3601 }
3602
3603 static void
3604 dhcp_readbpf(void *arg, unsigned short events)
3605 {
3606 struct interface *ifp = arg;
3607 uint8_t buf[FRAMELEN_MAX];
3608 ssize_t bytes;
3609 struct dhcp_state *state = D_STATE(ifp);
3610 struct bpf *bpf = state->bpf;
3611
3612 if (events != ELE_READ)
3613 logerrx("%s: unexpected event 0x%04x", __func__, events);
3614
3615 bpf->bpf_flags &= ~BPF_EOF;
3616 while (!(bpf->bpf_flags & BPF_EOF)) {
3617 bytes = bpf_read(bpf, buf, sizeof(buf));
3618 if (bytes == -1) {
3619 if (state->state != DHS_NONE) {
3620 logerr("%s: %s", __func__, ifp->name);
3621 dhcp_close(ifp);
3622 }
3623 break;
3624 }
3625 dhcp_packet(ifp, buf, (size_t)bytes, bpf->bpf_flags);
3626 /* Check we still have a state after processing. */
3627 if ((state = D_STATE(ifp)) == NULL)
3628 break;
3629 if ((bpf = state->bpf) == NULL)
3630 break;
3631 }
3632 }
3633
3634 void
3635 dhcp_recvmsg(struct dhcpcd_ctx *ctx, struct msghdr *msg)
3636 {
3637 struct sockaddr_in *from = (struct sockaddr_in *)msg->msg_name;
3638 struct iovec *iov = &msg->msg_iov[0];
3639 struct interface *ifp;
3640 const struct dhcp_state *state;
3641
3642 ifp = if_findifpfromcmsg(ctx, msg, NULL);
3643 if (ifp == NULL) {
3644 logerr(__func__);
3645 return;
3646 }
3647 state = D_CSTATE(ifp);
3648 if (state == NULL) {
3649 /* Try re-directing it to another interface. */
3650 dhcp_redirect_dhcp(ifp, (struct bootp *)iov->iov_base,
3651 iov->iov_len, &from->sin_addr);
3652 return;
3653 }
3654
3655 if (state->bpf != NULL) {
3656 /* Avoid a duplicate read if BPF is open for the interface. */
3657 return;
3658 }
3659 #ifdef PRIVSEP
3660 if (IN_PRIVSEP(ctx)) {
3661 switch (state->state) {
3662 case DHS_BOUND: /* FALLTHROUGH */
3663 case DHS_RENEW:
3664 break;
3665 default:
3666 /* Any other state we ignore it or will receive
3667 * via BPF. */
3668 return;
3669 }
3670 }
3671 #endif
3672
3673 dhcp_handlebootp(ifp, iov->iov_base, iov->iov_len,
3674 &from->sin_addr);
3675 }
3676
3677 static void
3678 dhcp_readudp(struct dhcpcd_ctx *ctx, struct interface *ifp,
3679 unsigned short events)
3680 {
3681 const struct dhcp_state *state;
3682 struct sockaddr_in from;
3683 union {
3684 struct bootp bootp;
3685 uint8_t buf[10 * 1024]; /* Maximum MTU */
3686 } iovbuf;
3687 struct iovec iov = {
3688 .iov_base = iovbuf.buf,
3689 .iov_len = sizeof(iovbuf.buf),
3690 };
3691 union {
3692 struct cmsghdr hdr;
3693 #ifdef IP_RECVIF
3694 uint8_t buf[CMSG_SPACE(sizeof(struct sockaddr_dl))];
3695 #else
3696 uint8_t buf[CMSG_SPACE(sizeof(struct in_pktinfo))];
3697 #endif
3698 } cmsgbuf = { .buf = { 0 } };
3699 struct msghdr msg = {
3700 .msg_name = &from, .msg_namelen = sizeof(from),
3701 .msg_iov = &iov, .msg_iovlen = 1,
3702 .msg_control = cmsgbuf.buf, .msg_controllen = sizeof(cmsgbuf.buf),
3703 };
3704 int s;
3705 ssize_t bytes;
3706
3707 if (events != ELE_READ)
3708 logerrx("%s: unexpected event 0x%04x", __func__, events);
3709
3710 if (ifp != NULL) {
3711 state = D_CSTATE(ifp);
3712 s = state->udp_rfd;
3713 } else
3714 s = ctx->udp_rfd;
3715
3716 bytes = recvmsg(s, &msg, 0);
3717 if (bytes == -1) {
3718 logerr(__func__);
3719 return;
3720 }
3721
3722 iov.iov_len = (size_t)bytes;
3723 dhcp_recvmsg(ctx, &msg);
3724 }
3725
3726 static void
3727 dhcp_handleudp(void *arg, unsigned short events)
3728 {
3729 struct dhcpcd_ctx *ctx = arg;
3730
3731 dhcp_readudp(ctx, NULL, events);
3732 }
3733
3734 static void
3735 dhcp_handleifudp(void *arg, unsigned short events)
3736 {
3737 struct interface *ifp = arg;
3738
3739 dhcp_readudp(ifp->ctx, ifp, events);
3740 }
3741
3742 static int
3743 dhcp_openbpf(struct interface *ifp)
3744 {
3745 struct dhcp_state *state;
3746
3747 state = D_STATE(ifp);
3748
3749 #ifdef PRIVSEP
3750 if (IN_PRIVSEP_SE(ifp->ctx)) {
3751 if (ps_bpf_openbootp(ifp) == -1) {
3752 logerr(__func__);
3753 return -1;
3754 }
3755 return 0;
3756 }
3757 #endif
3758
3759 if (state->bpf != NULL)
3760 return 0;
3761
3762 state->bpf = bpf_open(ifp, bpf_bootp, NULL);
3763 if (state->bpf == NULL) {
3764 if (errno == ENOENT) {
3765 logerrx("%s not found", bpf_name);
3766 /* May as well disable IPv4 entirely at
3767 * this point as we really need it. */
3768 ifp->options->options &= ~DHCPCD_IPV4;
3769 } else
3770 logerr("%s: %s", __func__, ifp->name);
3771 return -1;
3772 }
3773
3774 if (eloop_event_add(ifp->ctx->eloop, state->bpf->bpf_fd, ELE_READ,
3775 dhcp_readbpf, ifp) == -1)
3776 logerr("%s: eloop_event_add", __func__);
3777 return 0;
3778 }
3779
3780 void
3781 dhcp_free(struct interface *ifp)
3782 {
3783 struct dhcp_state *state = D_STATE(ifp);
3784 struct dhcpcd_ctx *ctx;
3785
3786 dhcp_close(ifp);
3787 #ifdef ARP
3788 arp_drop(ifp);
3789 #endif
3790 if (state) {
3791 state->state = DHS_NONE;
3792 free(state->old);
3793 free(state->new);
3794 free(state->offer);
3795 free(state->clientid);
3796 free(state);
3797 }
3798
3799 ctx = ifp->ctx;
3800 /* If we don't have any more DHCP enabled interfaces,
3801 * close the global socket and release resources */
3802 if (ctx->ifaces) {
3803 TAILQ_FOREACH(ifp, ctx->ifaces, next) {
3804 state = D_STATE(ifp);
3805 if (state != NULL && state->state != DHS_NONE)
3806 break;
3807 }
3808 }
3809 if (ifp == NULL) {
3810 if (ctx->udp_rfd != -1) {
3811 eloop_event_delete(ctx->eloop, ctx->udp_rfd);
3812 close(ctx->udp_rfd);
3813 ctx->udp_rfd = -1;
3814 }
3815 if (ctx->udp_wfd != -1) {
3816 close(ctx->udp_wfd);
3817 ctx->udp_wfd = -1;
3818 }
3819
3820 free(ctx->opt_buffer);
3821 ctx->opt_buffer = NULL;
3822 ctx->opt_buffer_len = 0;
3823 }
3824 }
3825
3826 static int
3827 dhcp_initstate(struct interface *ifp)
3828 {
3829 struct dhcp_state *state;
3830
3831 state = D_STATE(ifp);
3832 if (state != NULL)
3833 return 0;
3834
3835 ifp->if_data[IF_DATA_DHCP] = calloc(1, sizeof(*state));
3836 state = D_STATE(ifp);
3837 if (state == NULL)
3838 return -1;
3839
3840 state->state = DHS_NONE;
3841 /* 0 is a valid fd, so init to -1 */
3842 state->udp_rfd = -1;
3843 #ifdef ARPING
3844 state->arping_index = -1;
3845 #endif
3846 return 1;
3847 }
3848
3849 static int
3850 dhcp_init(struct interface *ifp)
3851 {
3852 struct dhcp_state *state;
3853 struct if_options *ifo;
3854 uint8_t len;
3855 char buf[(sizeof(ifo->clientid) - 1) * 3];
3856
3857 if (dhcp_initstate(ifp) == -1)
3858 return -1;
3859
3860 state = D_STATE(ifp);
3861 state->state = DHS_INIT;
3862 state->reason = "PREINIT";
3863 state->nakoff = 0;
3864 dhcp_set_leasefile(state->leasefile, sizeof(state->leasefile),
3865 AF_INET, ifp);
3866
3867 ifo = ifp->options;
3868 /* We need to drop the leasefile so that dhcp_start
3869 * doesn't load it. */
3870 if (ifo->options & DHCPCD_REQUEST)
3871 dhcp_unlink(ifp->ctx, state->leasefile);
3872
3873 free(state->clientid);
3874 state->clientid = NULL;
3875
3876 if (ifo->options & DHCPCD_ANONYMOUS) {
3877 /* Removing the option could show that we want anonymous.
3878 * As such keep it as it's already in the hwaddr field. */
3879 goto make_clientid;
3880 } else if (*ifo->clientid) {
3881 state->clientid = malloc((size_t)(ifo->clientid[0] + 1));
3882 if (state->clientid == NULL)
3883 goto eexit;
3884 memcpy(state->clientid, ifo->clientid,
3885 (size_t)(ifo->clientid[0]) + 1);
3886 } else if (ifo->options & DHCPCD_CLIENTID) {
3887 if (ifo->options & DHCPCD_DUID) {
3888 state->clientid = malloc(ifp->ctx->duid_len + 6);
3889 if (state->clientid == NULL)
3890 goto eexit;
3891 state->clientid[0] =(uint8_t)(ifp->ctx->duid_len + 5);
3892 state->clientid[1] = 255; /* RFC 4361 */
3893 memcpy(state->clientid + 2, ifo->iaid, 4);
3894 memcpy(state->clientid + 6, ifp->ctx->duid,
3895 ifp->ctx->duid_len);
3896 } else {
3897 make_clientid:
3898 len = (uint8_t)(ifp->hwlen + 1);
3899 state->clientid = malloc((size_t)len + 1);
3900 if (state->clientid == NULL)
3901 goto eexit;
3902 state->clientid[0] = len;
3903 state->clientid[1] = (uint8_t)ifp->hwtype;
3904 memcpy(state->clientid + 2, ifp->hwaddr,
3905 ifp->hwlen);
3906 }
3907 }
3908
3909 if (ifo->options & DHCPCD_DUID)
3910 /* Don't bother logging as DUID and IAID are reported
3911 * at device start. */
3912 return 0;
3913
3914 if (ifo->options & DHCPCD_CLIENTID && state->clientid != NULL)
3915 logdebugx("%s: using ClientID %s", ifp->name,
3916 hwaddr_ntoa(state->clientid + 1, state->clientid[0],
3917 buf, sizeof(buf)));
3918 else if (ifp->hwlen)
3919 logdebugx("%s: using hwaddr %s", ifp->name,
3920 hwaddr_ntoa(ifp->hwaddr, ifp->hwlen, buf, sizeof(buf)));
3921 return 0;
3922
3923 eexit:
3924 logerr(__func__);
3925 return -1;
3926 }
3927
3928 static void
3929 dhcp_start1(void *arg)
3930 {
3931 struct interface *ifp = arg;
3932 struct dhcpcd_ctx *ctx = ifp->ctx;
3933 struct if_options *ifo = ifp->options;
3934 struct dhcp_state *state;
3935 uint32_t l;
3936 int nolease;
3937
3938 if (!(ifo->options & DHCPCD_IPV4))
3939 return;
3940
3941 /* Listen on *.*.*.*:bootpc so that the kernel never sends an
3942 * ICMP port unreachable message back to the DHCP server.
3943 * Only do this in manager mode so we don't swallow messages
3944 * for dhcpcd running on another interface. */
3945 if ((ctx->options & (DHCPCD_MANAGER|DHCPCD_PRIVSEP)) == DHCPCD_MANAGER
3946 && ctx->udp_rfd == -1)
3947 {
3948 ctx->udp_rfd = dhcp_openudp(NULL);
3949 if (ctx->udp_rfd == -1) {
3950 logerr(__func__);
3951 return;
3952 }
3953 if (eloop_event_add(ctx->eloop, ctx->udp_rfd, ELE_READ,
3954 dhcp_handleudp, ctx) == -1)
3955 logerr("%s: eloop_event_add", __func__);
3956 }
3957 if (!IN_PRIVSEP(ctx) && ctx->udp_wfd == -1) {
3958 ctx->udp_wfd = xsocket(PF_INET, SOCK_RAW|SOCK_CXNB,IPPROTO_UDP);
3959 if (ctx->udp_wfd == -1) {
3960 logerr(__func__);
3961 return;
3962 }
3963 }
3964
3965 if (dhcp_init(ifp) == -1) {
3966 logerr("%s: dhcp_init", ifp->name);
3967 return;
3968 }
3969
3970 state = D_STATE(ifp);
3971 clock_gettime(CLOCK_MONOTONIC, &state->started);
3972 state->interval = 0;
3973 free(state->offer);
3974 state->offer = NULL;
3975 state->offer_len = 0;
3976
3977 #ifdef ARPING
3978 if (ifo->arping_len && state->arping_index < ifo->arping_len) {
3979 dhcp_arping(ifp);
3980 return;
3981 }
3982 #endif
3983
3984 if (ifo->options & DHCPCD_STATIC) {
3985 dhcp_static(ifp);
3986 return;
3987 }
3988
3989 if (ifo->options & DHCPCD_INFORM) {
3990 dhcp_inform(ifp);
3991 return;
3992 }
3993
3994 /* We don't want to read the old lease if we NAK an old test */
3995 nolease = state->offer && ifp->ctx->options & DHCPCD_TEST;
3996 if (!nolease && ifo->options & DHCPCD_DHCP) {
3997 state->offer_len = read_lease(ifp, &state->offer);
3998 /* Check the saved lease matches the type we want */
3999 if (state->offer) {
4000 #ifdef IN_IFF_DUPLICATED
4001 struct in_addr addr;
4002 struct ipv4_addr *ia;
4003
4004 addr.s_addr = state->offer->yiaddr;
4005 ia = ipv4_iffindaddr(ifp, &addr, NULL);
4006 #endif
4007
4008 if ((!IS_DHCP(state->offer) &&
4009 !(ifo->options & DHCPCD_BOOTP)) ||
4010 #ifdef IN_IFF_DUPLICATED
4011 (ia && ia->addr_flags & IN_IFF_DUPLICATED) ||
4012 #endif
4013 (IS_DHCP(state->offer) &&
4014 ifo->options & DHCPCD_BOOTP))
4015 {
4016 free(state->offer);
4017 state->offer = NULL;
4018 state->offer_len = 0;
4019 }
4020 }
4021 }
4022 if (state->offer) {
4023 struct ipv4_addr *ia;
4024 time_t mtime;
4025
4026 get_lease(ifp, &state->lease, state->offer, state->offer_len);
4027 state->lease.frominfo = 1;
4028 if (state->new == NULL &&
4029 (ia = ipv4_iffindaddr(ifp,
4030 &state->lease.addr, &state->lease.mask)) != NULL)
4031 {
4032 /* We still have the IP address from the last lease.
4033 * Fake add the address and routes from it so the lease
4034 * can be cleaned up. */
4035 state->new = malloc(state->offer_len);
4036 if (state->new) {
4037 memcpy(state->new,
4038 state->offer, state->offer_len);
4039 state->new_len = state->offer_len;
4040 state->addr = ia;
4041 state->added |= STATE_ADDED | STATE_FAKE;
4042 rt_build(ifp->ctx, AF_INET);
4043 } else
4044 logerr(__func__);
4045 }
4046 if (!IS_DHCP(state->offer)) {
4047 free(state->offer);
4048 state->offer = NULL;
4049 state->offer_len = 0;
4050 } else if (!(ifo->options & DHCPCD_LASTLEASE_EXTEND) &&
4051 state->lease.leasetime != DHCP_INFINITE_LIFETIME &&
4052 dhcp_filemtime(ifp->ctx, state->leasefile, &mtime) == 0)
4053 {
4054 time_t now;
4055
4056 /* Offset lease times and check expiry */
4057 now = time(NULL);
4058 if (now == -1 ||
4059 (time_t)state->lease.leasetime < now - mtime)
4060 {
4061 logdebugx("%s: discarding expired lease",
4062 ifp->name);
4063 free(state->offer);
4064 state->offer = NULL;
4065 state->offer_len = 0;
4066 state->lease.addr.s_addr = 0;
4067 /* Technically we should discard the lease
4068 * as it's expired, just as DHCPv6 addresses
4069 * would be by the kernel.
4070 * However, this may violate POLA so
4071 * we currently leave it be.
4072 * If we get a totally different lease from
4073 * the DHCP server we'll drop it anyway, as
4074 * we will on any other event which would
4075 * trigger a lease drop.
4076 * This should only happen if dhcpcd stops
4077 * running and the lease expires before
4078 * dhcpcd starts again. */
4079 #if 0
4080 if (state->new)
4081 dhcp_drop(ifp, "EXPIRE");
4082 #endif
4083 } else {
4084 l = (uint32_t)(now - mtime);
4085 state->lease.leasetime -= l;
4086 state->lease.renewaltime -= l;
4087 state->lease.rebindtime -= l;
4088 }
4089 }
4090 }
4091
4092 #ifdef IPV4LL
4093 if (!(ifo->options & DHCPCD_DHCP)) {
4094 if (ifo->options & DHCPCD_IPV4LL)
4095 ipv4ll_start(ifp);
4096 return;
4097 }
4098 #endif
4099
4100 if (state->offer == NULL ||
4101 !IS_DHCP(state->offer) ||
4102 ifo->options & DHCPCD_ANONYMOUS)
4103 dhcp_discover(ifp);
4104 else
4105 dhcp_reboot(ifp);
4106 }
4107
4108 void
4109 dhcp_start(struct interface *ifp)
4110 {
4111 unsigned int delay;
4112 #ifdef ARPING
4113 const struct dhcp_state *state;
4114 #endif
4115
4116 if (!(ifp->options->options & DHCPCD_IPV4))
4117 return;
4118
4119 /* If we haven't been given a netmask for our requested address,
4120 * set it now. */
4121 if (ifp->options->req_addr.s_addr != INADDR_ANY &&
4122 ifp->options->req_mask.s_addr == INADDR_ANY)
4123 ifp->options->req_mask.s_addr =
4124 ipv4_getnetmask(ifp->options->req_addr.s_addr);
4125
4126 /* If we haven't specified a ClientID and our hardware address
4127 * length is greater than BOOTP CHADDR then we enforce a ClientID
4128 * of the hardware address type and the hardware address.
4129 * If there is no hardware address and no ClientID set,
4130 * force a DUID based ClientID. */
4131 if (ifp->hwlen > 16)
4132 ifp->options->options |= DHCPCD_CLIENTID;
4133 else if (ifp->hwlen == 0 && !(ifp->options->options & DHCPCD_CLIENTID))
4134 ifp->options->options |= DHCPCD_CLIENTID | DHCPCD_DUID;
4135
4136 /* Firewire and InfiniBand interfaces require ClientID and
4137 * the broadcast option being set. */
4138 switch (ifp->hwtype) {
4139 case ARPHRD_IEEE1394: /* FALLTHROUGH */
4140 case ARPHRD_INFINIBAND:
4141 ifp->options->options |= DHCPCD_CLIENTID | DHCPCD_BROADCAST;
4142 break;
4143 }
4144
4145 /* If we violate RFC2131 section 3.7 then require ARP
4146 * to detect if any other client wants our address. */
4147 if (ifp->options->options & DHCPCD_LASTLEASE_EXTEND)
4148 ifp->options->options |= DHCPCD_ARP;
4149
4150 /* No point in delaying a static configuration */
4151 if (ifp->options->options & DHCPCD_STATIC ||
4152 !(ifp->options->options & DHCPCD_INITIAL_DELAY))
4153 {
4154 dhcp_start1(ifp);
4155 return;
4156 }
4157
4158 #ifdef ARPING
4159 /* If we have arpinged then we have already delayed. */
4160 state = D_CSTATE(ifp);
4161 if (state != NULL && state->arping_index != -1) {
4162 dhcp_start1(ifp);
4163 return;
4164 }
4165 #endif
4166 delay = MSEC_PER_SEC +
4167 (arc4random_uniform(MSEC_PER_SEC * 2) - MSEC_PER_SEC);
4168 logdebugx("%s: delaying IPv4 for %0.1f seconds",
4169 ifp->name, (float)delay / MSEC_PER_SEC);
4170
4171 eloop_timeout_add_msec(ifp->ctx->eloop, delay, dhcp_start1, ifp);
4172 }
4173
4174 void
4175 dhcp_abort(struct interface *ifp)
4176 {
4177 struct dhcp_state *state;
4178
4179 state = D_STATE(ifp);
4180 #ifdef ARPING
4181 if (state != NULL)
4182 state->arping_index = -1;
4183 #endif
4184
4185 eloop_timeout_delete(ifp->ctx->eloop, dhcp_start1, ifp);
4186
4187 if (state != NULL && state->added) {
4188 rt_build(ifp->ctx, AF_INET);
4189 #ifdef ARP
4190 if (ifp->options->options & DHCPCD_ARP)
4191 arp_announceaddr(ifp->ctx, &state->addr->addr);
4192 #endif
4193 }
4194 }
4195
4196 struct ipv4_addr *
4197 dhcp_handleifa(int cmd, struct ipv4_addr *ia, pid_t pid)
4198 {
4199 struct interface *ifp;
4200 struct dhcp_state *state;
4201 struct if_options *ifo;
4202 uint8_t i;
4203
4204 ifp = ia->iface;
4205 state = D_STATE(ifp);
4206 if (state == NULL || state->state == DHS_NONE)
4207 return ia;
4208
4209 if (cmd == RTM_DELADDR) {
4210 if (state->addr == ia) {
4211 loginfox("%s: pid %d deleted IP address %s",
4212 ifp->name, pid, ia->saddr);
4213 dhcp_close(ifp);
4214 state->addr = NULL;
4215 /* Don't clear the added state as we need
4216 * to drop the lease. */
4217 dhcp_drop(ifp, "EXPIRE");
4218 dhcp_start1(ifp);
4219 return ia;
4220 }
4221 }
4222
4223 if (cmd != RTM_NEWADDR)
4224 return ia;
4225
4226 #ifdef IN_IFF_NOTUSEABLE
4227 if (!(ia->addr_flags & IN_IFF_NOTUSEABLE))
4228 dhcp_finish_dad(ifp, &ia->addr);
4229 else if (ia->addr_flags & IN_IFF_DUPLICATED)
4230 return dhcp_addr_duplicated(ifp, &ia->addr) ? NULL : ia;
4231 #endif
4232
4233 ifo = ifp->options;
4234
4235 #ifdef PRIVSEP
4236 if (IN_PRIVSEP_SE(ifp->ctx) &&
4237 !(ifp->ctx->options & (DHCPCD_MANAGER | DHCPCD_CONFIGURE)) &&
4238 IN_ARE_ADDR_EQUAL(&state->lease.addr, &ia->addr))
4239 {
4240 state->addr = ia;
4241 state->added = STATE_ADDED;
4242 dhcp_closebpf(ifp);
4243 if (ps_inet_openbootp(ia) == -1)
4244 logerr(__func__);
4245 }
4246 #endif
4247
4248 /* If we have requested a specific address, return now.
4249 * The below code is only for when inform or static has been
4250 * requested without a specific address. */
4251 if (ifo->req_addr.s_addr != INADDR_ANY)
4252 return ia;
4253
4254 /* Only inform if we are NOT in the inform state or bound. */
4255 if (ifo->options & DHCPCD_INFORM) {
4256 if (state->state != DHS_INFORM && state->state != DHS_BOUND)
4257 dhcp_inform(ifp);
4258 return ia;
4259 }
4260
4261 /* Static and inform are mutually exclusive. If not static, return. */
4262 if (!(ifo->options & DHCPCD_STATIC))
4263 return ia;
4264
4265 free(state->old);
4266 state->old = state->new;
4267 state->new_len = dhcp_message_new(&state->new, &ia->addr, &ia->mask);
4268 if (state->new == NULL)
4269 return ia;
4270
4271 if (ifp->flags & IFF_POINTOPOINT) {
4272 for (i = 1; i < 255; i++)
4273 if (i != DHO_ROUTER && has_option_mask(ifo->dstmask,i))
4274 dhcp_message_add_addr(state->new, i, ia->brd);
4275 }
4276
4277 state->reason = "STATIC";
4278 rt_build(ifp->ctx, AF_INET);
4279 script_runreason(ifp, state->reason);
4280
4281 return ia;
4282 }
4283
4284 #ifndef SMALL
4285 int
4286 dhcp_dump(struct interface *ifp)
4287 {
4288 struct dhcp_state *state;
4289
4290 ifp->if_data[IF_DATA_DHCP] = state = calloc(1, sizeof(*state));
4291 if (state == NULL) {
4292 logerr(__func__);
4293 return -1;
4294 }
4295 state->new_len = read_lease(ifp, &state->new);
4296 if (state->new == NULL) {
4297 logerr("read_lease");
4298 return -1;
4299 }
4300 state->reason = "DUMP";
4301 return script_runreason(ifp, state->reason);
4302 }
4303 #endif
DragonFly BSD