rarpd.c revision 1.60 1 1.60 martin /* $NetBSD: rarpd.c,v 1.60 2018/02/13 10:17:04 martin Exp $ */
2 1.9 thorpej
3 1.1 deraadt /*
4 1.1 deraadt * Copyright (c) 1990 The Regents of the University of California.
5 1.1 deraadt * All rights reserved.
6 1.1 deraadt *
7 1.1 deraadt * Redistribution and use in source and binary forms, with or without
8 1.1 deraadt * modification, are permitted provided that: (1) source code distributions
9 1.1 deraadt * retain the above copyright notice and this paragraph in its entirety, (2)
10 1.1 deraadt * distributions including binary code include the above copyright notice and
11 1.1 deraadt * this paragraph in its entirety in the documentation or other materials
12 1.56 martin * provided with the distribution. Neither the name of
13 1.1 deraadt * the University nor the names of its contributors may be used to endorse
14 1.1 deraadt * or promote products derived from this software without specific prior
15 1.1 deraadt * written permission.
16 1.56 martin *
17 1.1 deraadt * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 1.1 deraadt * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 1.1 deraadt * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 1.1 deraadt */
21 1.19 lukem #include <sys/cdefs.h>
22 1.1 deraadt #ifndef lint
23 1.57 lukem __COPYRIGHT("@(#) Copyright (c) 1990\
24 1.57 lukem The Regents of the University of California. All rights reserved.");
25 1.19 lukem #endif /* not lint */
26 1.1 deraadt
27 1.1 deraadt #ifndef lint
28 1.60 martin __RCSID("$NetBSD: rarpd.c,v 1.60 2018/02/13 10:17:04 martin Exp $");
29 1.1 deraadt #endif
30 1.1 deraadt
31 1.1 deraadt
32 1.1 deraadt /*
33 1.1 deraadt * rarpd - Reverse ARP Daemon
34 1.1 deraadt *
35 1.27 fair * Usage: rarpd -a [-d|-f] [-l]
36 1.47 lukem * rarpd [-d|-f] [-l] interface [...]
37 1.1 deraadt */
38 1.1 deraadt
39 1.34 kleink #include <sys/param.h>
40 1.21 lukem #include <sys/file.h>
41 1.1 deraadt #include <sys/time.h>
42 1.1 deraadt #include <sys/socket.h>
43 1.1 deraadt #include <sys/ioctl.h>
44 1.21 lukem
45 1.21 lukem #include <net/bpf.h>
46 1.1 deraadt #include <net/if.h>
47 1.7 mycroft #include <net/if_dl.h>
48 1.16 is #ifdef __NetBSD__
49 1.16 is #include <net/if_ether.h>
50 1.16 is #endif
51 1.7 mycroft #include <net/if_types.h>
52 1.1 deraadt #include <netinet/in.h>
53 1.16 is #ifdef __NetBSD__
54 1.16 is #include <netinet/if_inarp.h>
55 1.16 is #else
56 1.1 deraadt #include <netinet/if_ether.h>
57 1.16 is #endif
58 1.21 lukem
59 1.1 deraadt #include <arpa/inet.h>
60 1.21 lukem
61 1.31 kleink #include <errno.h>
62 1.1 deraadt #include <dirent.h>
63 1.53 christos #include <paths.h>
64 1.21 lukem #include <netdb.h>
65 1.21 lukem #include <stdio.h>
66 1.21 lukem #include <stdlib.h>
67 1.21 lukem #include <string.h>
68 1.21 lukem #include <syslog.h>
69 1.21 lukem #include <unistd.h>
70 1.33 thorpej #include <util.h>
71 1.37 itojun #include <ifaddrs.h>
72 1.25 mrg
73 1.1 deraadt #define FATAL 1 /* fatal error occurred */
74 1.1 deraadt #define NONFATAL 0 /* non fatal error occurred */
75 1.1 deraadt
76 1.1 deraadt /*
77 1.1 deraadt * The structure for each interface.
78 1.1 deraadt */
79 1.1 deraadt struct if_info {
80 1.1 deraadt int ii_fd; /* BPF file descriptor */
81 1.1 deraadt u_char ii_eaddr[6]; /* Ethernet address of this interface */
82 1.29 matt u_int32_t ii_ipaddr; /* IP address of this interface */
83 1.29 matt u_int32_t ii_netmask; /* subnet or net mask */
84 1.29 matt char *ii_name; /* interface name */
85 1.29 matt struct if_info *ii_alias;
86 1.1 deraadt struct if_info *ii_next;
87 1.1 deraadt };
88 1.1 deraadt /*
89 1.1 deraadt * The list of all interfaces that are being listened to. rarp_loop()
90 1.1 deraadt * "selects" on the descriptors in this list.
91 1.1 deraadt */
92 1.59 joerg static struct if_info *iflist;
93 1.1 deraadt
94 1.59 joerg static u_int32_t choose_ipaddr(u_int32_t **, u_int32_t, u_int32_t);
95 1.59 joerg static void debug(const char *,...) __printflike(1, 2);
96 1.59 joerg static void init_some(char *name);
97 1.59 joerg static void init_one(char *, u_int32_t);
98 1.59 joerg static u_int32_t ipaddrtonetmask(u_int32_t);
99 1.59 joerg static void lookup_eaddr(char *, u_char *);
100 1.59 joerg static void lookup_ipaddr(char *, u_int32_t *, u_int32_t *);
101 1.59 joerg static void rarp_loop(void) __dead;
102 1.59 joerg static int rarp_open(char *);
103 1.59 joerg static void rarp_process(struct if_info *, u_char *);
104 1.59 joerg static void rarp_reply(struct if_info *, struct ether_header *, u_int32_t,
105 1.59 joerg struct hostent *);
106 1.59 joerg static void rarperr(int, const char *,...) __printflike(2, 3);
107 1.22 is
108 1.22 is #if defined(__NetBSD__)
109 1.22 is #include "mkarp.h"
110 1.22 is #else
111 1.59 joerg static void update_arptab(u_char *, u_int32_t);
112 1.22 is #endif
113 1.22 is
114 1.59 joerg __dead static void usage(void);
115 1.19 lukem
116 1.45 wiz static int bpf_open(void);
117 1.45 wiz static int rarp_check(u_char *, int);
118 1.1 deraadt
119 1.8 thorpej #ifdef REQUIRE_TFTPBOOT
120 1.59 joerg static int rarp_bootable(u_int32_t);
121 1.8 thorpej #endif
122 1.8 thorpej
123 1.59 joerg static int aflag = 0; /* listen on "all" interfaces */
124 1.59 joerg static int dflag = 0; /* print debugging messages */
125 1.59 joerg static int fflag = 0; /* don't fork */
126 1.59 joerg static int lflag = 0; /* log all replies */
127 1.1 deraadt
128 1.12 jtc int
129 1.45 wiz main(int argc, char **argv)
130 1.1 deraadt {
131 1.28 mrg int op;
132 1.1 deraadt
133 1.53 christos setprogname(*argv);
134 1.1 deraadt /* All error reporting is done through syslogs. */
135 1.53 christos openlog(getprogname(), LOG_PID, LOG_DAEMON);
136 1.1 deraadt
137 1.1 deraadt opterr = 0;
138 1.24 mrg while ((op = getopt(argc, argv, "adfl")) != -1) {
139 1.1 deraadt switch (op) {
140 1.1 deraadt case 'a':
141 1.1 deraadt ++aflag;
142 1.1 deraadt break;
143 1.1 deraadt
144 1.1 deraadt case 'd':
145 1.1 deraadt ++dflag;
146 1.1 deraadt break;
147 1.1 deraadt
148 1.1 deraadt case 'f':
149 1.1 deraadt ++fflag;
150 1.1 deraadt break;
151 1.1 deraadt
152 1.24 mrg case 'l':
153 1.24 mrg ++lflag;
154 1.24 mrg break;
155 1.24 mrg
156 1.1 deraadt default:
157 1.1 deraadt usage();
158 1.1 deraadt /* NOTREACHED */
159 1.1 deraadt }
160 1.1 deraadt }
161 1.46 thorpej argc -= optind;
162 1.46 thorpej argv += optind;
163 1.46 thorpej
164 1.46 thorpej if ((aflag && argc != 0) || (!aflag && argc == 0))
165 1.1 deraadt usage();
166 1.1 deraadt
167 1.44 itojun if ((!fflag) && (!dflag)) {
168 1.44 itojun if (daemon(0, 0))
169 1.44 itojun rarperr(FATAL, "daemon");
170 1.44 itojun pidfile(NULL);
171 1.44 itojun }
172 1.44 itojun
173 1.1 deraadt if (aflag)
174 1.51 tron init_some(NULL);
175 1.46 thorpej else {
176 1.46 thorpej while (argc--)
177 1.51 tron init_some(*argv++);
178 1.46 thorpej }
179 1.1 deraadt
180 1.1 deraadt rarp_loop();
181 1.19 lukem /* NOTREACHED */
182 1.19 lukem return (0);
183 1.1 deraadt }
184 1.19 lukem
185 1.1 deraadt /*
186 1.1 deraadt * Add 'ifname' to the interface list. Lookup its IP address and network
187 1.1 deraadt * mask and Ethernet address, and open a BPF file for it.
188 1.1 deraadt */
189 1.59 joerg static void
190 1.45 wiz init_one(char *ifname, u_int32_t ipaddr)
191 1.1 deraadt {
192 1.29 matt struct if_info *h;
193 1.1 deraadt struct if_info *p;
194 1.23 fair int fd;
195 1.23 fair
196 1.29 matt for (h = iflist; h != NULL; h = h->ii_next) {
197 1.29 matt if (!strcmp(h->ii_name, ifname))
198 1.29 matt break;
199 1.29 matt }
200 1.29 matt if (h == NULL) {
201 1.29 matt fd = rarp_open(ifname);
202 1.29 matt if (fd < 0)
203 1.29 matt return;
204 1.29 matt } else {
205 1.29 matt fd = h->ii_fd;
206 1.29 matt }
207 1.1 deraadt
208 1.7 mycroft p = (struct if_info *)malloc(sizeof(*p));
209 1.1 deraadt if (p == 0) {
210 1.19 lukem rarperr(FATAL, "malloc: %s", strerror(errno));
211 1.1 deraadt /* NOTREACHED */
212 1.1 deraadt }
213 1.29 matt p->ii_name = strdup(ifname);
214 1.29 matt if (p->ii_name == 0) {
215 1.29 matt rarperr(FATAL, "malloc: %s", strerror(errno));
216 1.29 matt /* NOTREACHED */
217 1.29 matt }
218 1.29 matt if (h != NULL) {
219 1.29 matt p->ii_alias = h->ii_alias;
220 1.29 matt h->ii_alias = p;
221 1.29 matt } else {
222 1.29 matt p->ii_next = iflist;
223 1.29 matt iflist = p;
224 1.29 matt }
225 1.1 deraadt
226 1.23 fair p->ii_fd = fd;
227 1.29 matt p->ii_ipaddr = ipaddr;
228 1.1 deraadt lookup_eaddr(ifname, p->ii_eaddr);
229 1.1 deraadt lookup_ipaddr(ifname, &p->ii_ipaddr, &p->ii_netmask);
230 1.1 deraadt }
231 1.19 lukem
232 1.1 deraadt /*
233 1.1 deraadt * Initialize all "candidate" interfaces that are in the system
234 1.1 deraadt * configuration list. A "candidate" is up, not loopback and not
235 1.1 deraadt * point to point.
236 1.1 deraadt */
237 1.59 joerg static void
238 1.51 tron init_some(char *name)
239 1.1 deraadt {
240 1.37 itojun struct ifaddrs *ifap, *ifa, *p;
241 1.37 itojun
242 1.37 itojun if (getifaddrs(&ifap) != 0) {
243 1.37 itojun rarperr(FATAL, "getifaddrs: %s", strerror(errno));
244 1.37 itojun /* NOTREACHED */
245 1.37 itojun }
246 1.37 itojun
247 1.37 itojun p = NULL;
248 1.37 itojun for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
249 1.37 itojun #define SIN(s) ((struct sockaddr_in *) (s))
250 1.37 itojun if (ifa->ifa_addr->sa_family != AF_INET)
251 1.37 itojun continue;
252 1.51 tron if (name && strcmp(name, ifa->ifa_name))
253 1.51 tron continue;
254 1.37 itojun if (p && !strcmp(p->ifa_name, ifa->ifa_name) &&
255 1.37 itojun SIN(p->ifa_addr)->sin_addr.s_addr == SIN(ifa->ifa_addr)->sin_addr.s_addr)
256 1.37 itojun continue;
257 1.37 itojun p = ifa;
258 1.37 itojun if ((ifa->ifa_flags &
259 1.37 itojun (IFF_UP | IFF_LOOPBACK | IFF_POINTOPOINT)) != IFF_UP)
260 1.37 itojun continue;
261 1.37 itojun init_one(ifa->ifa_name, SIN(ifa->ifa_addr)->sin_addr.s_addr);
262 1.37 itojun #undef SIN
263 1.37 itojun }
264 1.37 itojun freeifaddrs(ifap);
265 1.1 deraadt }
266 1.1 deraadt
267 1.59 joerg static void
268 1.45 wiz usage(void)
269 1.1 deraadt {
270 1.53 christos (void) fprintf(stderr, "Usage: %s -a [-d|-f] [-l]\n", getprogname());
271 1.53 christos (void) fprintf(stderr, "\t%s [-d|-f] [-l] interface [...]\n",
272 1.53 christos getprogname());
273 1.1 deraadt exit(1);
274 1.1 deraadt }
275 1.1 deraadt
276 1.1 deraadt static int
277 1.45 wiz bpf_open(void)
278 1.1 deraadt {
279 1.1 deraadt int fd;
280 1.53 christos const char *device = _PATH_BPF;
281 1.53 christos fd = open(device, O_RDWR);
282 1.1 deraadt
283 1.1 deraadt if (fd < 0) {
284 1.19 lukem rarperr(FATAL, "%s: %s", device, strerror(errno));
285 1.1 deraadt /* NOTREACHED */
286 1.1 deraadt }
287 1.1 deraadt return fd;
288 1.1 deraadt }
289 1.1 deraadt /*
290 1.1 deraadt * Open a BPF file and attach it to the interface named 'device'.
291 1.1 deraadt * Set immediate mode, and set a filter that accepts only RARP requests.
292 1.1 deraadt */
293 1.59 joerg static int
294 1.45 wiz rarp_open(char *device)
295 1.1 deraadt {
296 1.1 deraadt int fd;
297 1.1 deraadt struct ifreq ifr;
298 1.1 deraadt u_int dlt;
299 1.1 deraadt int immediate;
300 1.50 darrenr u_int bufsize;
301 1.1 deraadt
302 1.1 deraadt static struct bpf_insn insns[] = {
303 1.1 deraadt BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 12),
304 1.1 deraadt BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ETHERTYPE_REVARP, 0, 3),
305 1.1 deraadt BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 20),
306 1.6 cgd BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, ARPOP_REVREQUEST, 0, 1),
307 1.16 is BPF_STMT(BPF_RET | BPF_K,
308 1.16 is sizeof(struct arphdr) +
309 1.16 is 2 * ETHER_ADDR_LEN + 2 * sizeof(struct in_addr) +
310 1.1 deraadt sizeof(struct ether_header)),
311 1.1 deraadt BPF_STMT(BPF_RET | BPF_K, 0),
312 1.1 deraadt };
313 1.1 deraadt static struct bpf_program filter = {
314 1.1 deraadt sizeof insns / sizeof(insns[0]),
315 1.1 deraadt insns
316 1.1 deraadt };
317 1.1 deraadt
318 1.1 deraadt fd = bpf_open();
319 1.1 deraadt
320 1.1 deraadt /* Set immediate mode so packets are processed as they arrive. */
321 1.1 deraadt immediate = 1;
322 1.1 deraadt if (ioctl(fd, BIOCIMMEDIATE, &immediate) < 0) {
323 1.19 lukem rarperr(FATAL, "BIOCIMMEDIATE: %s", strerror(errno));
324 1.1 deraadt /* NOTREACHED */
325 1.1 deraadt }
326 1.50 darrenr /* Set a 32k buffer size for kernel use */
327 1.50 darrenr bufsize = 32768;
328 1.50 darrenr if (ioctl(fd, BIOCSBLEN, &bufsize) < 0) {
329 1.50 darrenr rarperr(NONFATAL, "BIOCSBLEN:%d: %s", bufsize, strerror(errno));
330 1.50 darrenr }
331 1.52 jrf (void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
332 1.1 deraadt if (ioctl(fd, BIOCSETIF, (caddr_t) & ifr) < 0) {
333 1.23 fair if (aflag) { /* for -a skip non-ethernet interfaces */
334 1.23 fair close(fd);
335 1.23 fair return(-1);
336 1.23 fair }
337 1.19 lukem rarperr(FATAL, "BIOCSETIF: %s", strerror(errno));
338 1.1 deraadt /* NOTREACHED */
339 1.1 deraadt }
340 1.1 deraadt /* Check that the data link layer is an Ethernet; this code won't work
341 1.1 deraadt * with anything else. */
342 1.1 deraadt if (ioctl(fd, BIOCGDLT, (caddr_t) & dlt) < 0) {
343 1.19 lukem rarperr(FATAL, "BIOCGDLT: %s", strerror(errno));
344 1.1 deraadt /* NOTREACHED */
345 1.1 deraadt }
346 1.1 deraadt if (dlt != DLT_EN10MB) {
347 1.23 fair if (aflag) { /* for -a skip non-ethernet interfaces */
348 1.23 fair close(fd);
349 1.23 fair return(-1);
350 1.23 fair }
351 1.19 lukem rarperr(FATAL, "%s is not an ethernet", device);
352 1.1 deraadt /* NOTREACHED */
353 1.1 deraadt }
354 1.1 deraadt /* Set filter program. */
355 1.1 deraadt if (ioctl(fd, BIOCSETF, (caddr_t) & filter) < 0) {
356 1.19 lukem rarperr(FATAL, "BIOCSETF: %s", strerror(errno));
357 1.1 deraadt /* NOTREACHED */
358 1.1 deraadt }
359 1.1 deraadt return fd;
360 1.1 deraadt }
361 1.1 deraadt /*
362 1.1 deraadt * Perform various sanity checks on the RARP request packet. Return
363 1.1 deraadt * false on failure and log the reason.
364 1.1 deraadt */
365 1.1 deraadt static int
366 1.45 wiz rarp_check(u_char *p, int len)
367 1.1 deraadt {
368 1.1 deraadt struct ether_header *ep = (struct ether_header *) p;
369 1.16 is #ifdef __NetBSD__
370 1.16 is struct arphdr *ap = (struct arphdr *) (p + sizeof(*ep));
371 1.16 is #else
372 1.1 deraadt struct ether_arp *ap = (struct ether_arp *) (p + sizeof(*ep));
373 1.16 is #endif
374 1.1 deraadt
375 1.58 lukem if (len < (int)(sizeof(*ep) + sizeof(*ap))) {
376 1.19 lukem rarperr(NONFATAL, "truncated request");
377 1.1 deraadt return 0;
378 1.1 deraadt }
379 1.16 is #ifdef __NetBSD__
380 1.16 is /* now that we know the fixed part of the ARP hdr is there: */
381 1.58 lukem if (len < (int)(sizeof(*ap) + 2 * ap->ar_hln + 2 * ap->ar_pln)) {
382 1.19 lukem rarperr(NONFATAL, "truncated request");
383 1.16 is return 0;
384 1.16 is }
385 1.16 is #endif
386 1.1 deraadt /* XXX This test might be better off broken out... */
387 1.11 mycroft #ifdef __FreeBSD__
388 1.11 mycroft /* BPF (incorrectly) returns this in host order. */
389 1.11 mycroft if (ep->ether_type != ETHERTYPE_REVARP ||
390 1.11 mycroft #else
391 1.1 deraadt if (ntohs (ep->ether_type) != ETHERTYPE_REVARP ||
392 1.11 mycroft #endif
393 1.16 is #ifdef __NetBSD__
394 1.16 is ntohs (ap->ar_hrd) != ARPHRD_ETHER ||
395 1.16 is ntohs (ap->ar_op) != ARPOP_REVREQUEST ||
396 1.16 is ntohs (ap->ar_pro) != ETHERTYPE_IP ||
397 1.16 is ap->ar_hln != 6 || ap->ar_pln != 4) {
398 1.16 is #else
399 1.1 deraadt ntohs (ap->arp_hrd) != ARPHRD_ETHER ||
400 1.6 cgd ntohs (ap->arp_op) != ARPOP_REVREQUEST ||
401 1.1 deraadt ntohs (ap->arp_pro) != ETHERTYPE_IP ||
402 1.1 deraadt ap->arp_hln != 6 || ap->arp_pln != 4) {
403 1.16 is #endif
404 1.19 lukem rarperr(NONFATAL, "request fails sanity check");
405 1.1 deraadt return 0;
406 1.1 deraadt }
407 1.16 is #ifdef __NetBSD__
408 1.21 lukem if (memcmp((char *) &ep->ether_shost, ar_sha(ap), 6) != 0) {
409 1.16 is #else
410 1.21 lukem if (memcmp((char *) &ep->ether_shost, ap->arp_sha, 6) != 0) {
411 1.16 is #endif
412 1.19 lukem rarperr(NONFATAL, "ether/arp sender address mismatch");
413 1.1 deraadt return 0;
414 1.1 deraadt }
415 1.55 mrg {
416 1.16 is #ifdef __NetBSD__
417 1.60 martin uint8_t *tha = ar_tha(ap);
418 1.55 mrg
419 1.55 mrg if (!tha || memcmp(ar_sha(ap), tha, 6) != 0) {
420 1.16 is #else
421 1.55 mrg if (memcmp((char *) &ap->arp_sha, (char *) &ap->arp_tha, 6) != 0) {
422 1.16 is #endif
423 1.55 mrg rarperr(NONFATAL, "ether/arp target address mismatch");
424 1.55 mrg return 0;
425 1.55 mrg }
426 1.1 deraadt }
427 1.1 deraadt return 1;
428 1.1 deraadt }
429 1.1 deraadt
430 1.1 deraadt /*
431 1.1 deraadt * Loop indefinitely listening for RARP requests on the
432 1.1 deraadt * interfaces in 'iflist'.
433 1.1 deraadt */
434 1.59 joerg static void
435 1.45 wiz rarp_loop(void)
436 1.1 deraadt {
437 1.1 deraadt u_char *buf, *bp, *ep;
438 1.1 deraadt int cc, fd;
439 1.1 deraadt fd_set fds, listeners;
440 1.1 deraadt int bufsize, maxfd = 0;
441 1.1 deraadt struct if_info *ii;
442 1.1 deraadt
443 1.1 deraadt if (iflist == 0) {
444 1.19 lukem rarperr(FATAL, "no interfaces");
445 1.1 deraadt /* NOTREACHED */
446 1.1 deraadt }
447 1.1 deraadt if (ioctl(iflist->ii_fd, BIOCGBLEN, (caddr_t) & bufsize) < 0) {
448 1.19 lukem rarperr(FATAL, "BIOCGBLEN: %s", strerror(errno));
449 1.1 deraadt /* NOTREACHED */
450 1.1 deraadt }
451 1.1 deraadt buf = (u_char *) malloc((unsigned) bufsize);
452 1.1 deraadt if (buf == 0) {
453 1.19 lukem rarperr(FATAL, "malloc: %s", strerror(errno));
454 1.1 deraadt /* NOTREACHED */
455 1.1 deraadt }
456 1.1 deraadt /*
457 1.1 deraadt * Find the highest numbered file descriptor for select().
458 1.1 deraadt * Initialize the set of descriptors to listen to.
459 1.1 deraadt */
460 1.1 deraadt FD_ZERO(&fds);
461 1.1 deraadt for (ii = iflist; ii; ii = ii->ii_next) {
462 1.1 deraadt FD_SET(ii->ii_fd, &fds);
463 1.1 deraadt if (ii->ii_fd > maxfd)
464 1.1 deraadt maxfd = ii->ii_fd;
465 1.1 deraadt }
466 1.1 deraadt while (1) {
467 1.1 deraadt listeners = fds;
468 1.1 deraadt if (select(maxfd + 1, &listeners, (struct fd_set *) 0,
469 1.1 deraadt (struct fd_set *) 0, (struct timeval *) 0) < 0) {
470 1.19 lukem rarperr(FATAL, "select: %s", strerror(errno));
471 1.1 deraadt /* NOTREACHED */
472 1.1 deraadt }
473 1.1 deraadt for (ii = iflist; ii; ii = ii->ii_next) {
474 1.1 deraadt fd = ii->ii_fd;
475 1.1 deraadt if (!FD_ISSET(fd, &listeners))
476 1.1 deraadt continue;
477 1.24 mrg again:
478 1.1 deraadt cc = read(fd, (char *) buf, bufsize);
479 1.1 deraadt /* Don't choke when we get ptraced */
480 1.1 deraadt if (cc < 0 && errno == EINTR)
481 1.1 deraadt goto again;
482 1.1 deraadt /* Due to a SunOS bug, after 2^31 bytes, the file
483 1.1 deraadt * offset overflows and read fails with EINVAL. The
484 1.1 deraadt * lseek() to 0 will fix things. */
485 1.1 deraadt if (cc < 0) {
486 1.1 deraadt if (errno == EINVAL &&
487 1.5 cgd (lseek(fd, 0, SEEK_CUR) + bufsize) < 0) {
488 1.26 mrg (void)lseek(fd, 0, 0);
489 1.1 deraadt goto again;
490 1.1 deraadt }
491 1.19 lukem rarperr(FATAL, "read: %s", strerror(errno));
492 1.1 deraadt /* NOTREACHED */
493 1.1 deraadt }
494 1.1 deraadt /* Loop through the packet(s) */
495 1.1 deraadt #define bhp ((struct bpf_hdr *)bp)
496 1.1 deraadt bp = buf;
497 1.1 deraadt ep = bp + cc;
498 1.1 deraadt while (bp < ep) {
499 1.45 wiz int caplen, hdrlen;
500 1.1 deraadt
501 1.1 deraadt caplen = bhp->bh_caplen;
502 1.1 deraadt hdrlen = bhp->bh_hdrlen;
503 1.36 abs debug("received packet on %s", ii->ii_name);
504 1.36 abs
505 1.1 deraadt if (rarp_check(bp + hdrlen, caplen))
506 1.1 deraadt rarp_process(ii, bp + hdrlen);
507 1.1 deraadt bp += BPF_WORDALIGN(hdrlen + caplen);
508 1.1 deraadt }
509 1.1 deraadt }
510 1.1 deraadt }
511 1.1 deraadt }
512 1.8 thorpej
513 1.8 thorpej #ifdef REQUIRE_TFTPBOOT
514 1.8 thorpej
515 1.1 deraadt #ifndef TFTP_DIR
516 1.1 deraadt #define TFTP_DIR "/tftpboot"
517 1.1 deraadt #endif
518 1.1 deraadt
519 1.1 deraadt /*
520 1.1 deraadt * True if this server can boot the host whose IP address is 'addr'.
521 1.1 deraadt * This check is made by looking in the tftp directory for the
522 1.1 deraadt * configuration file.
523 1.1 deraadt */
524 1.59 joerg static int
525 1.45 wiz rarp_bootable(u_int32_t addr)
526 1.1 deraadt {
527 1.45 wiz struct dirent *dent;
528 1.45 wiz DIR *d;
529 1.1 deraadt char ipname[9];
530 1.1 deraadt static DIR *dd = 0;
531 1.1 deraadt
532 1.49 itojun (void)snprintf(ipname, sizeof(ipname), "%08X", addr);
533 1.1 deraadt /* If directory is already open, rewind it. Otherwise, open it. */
534 1.1 deraadt if (d = dd)
535 1.1 deraadt rewinddir(d);
536 1.1 deraadt else {
537 1.1 deraadt if (chdir(TFTP_DIR) == -1) {
538 1.19 lukem rarperr(FATAL, "chdir: %s", strerror(errno));
539 1.1 deraadt /* NOTREACHED */
540 1.1 deraadt }
541 1.1 deraadt d = opendir(".");
542 1.1 deraadt if (d == 0) {
543 1.19 lukem rarperr(FATAL, "opendir: %s", strerror(errno));
544 1.1 deraadt /* NOTREACHED */
545 1.1 deraadt }
546 1.1 deraadt dd = d;
547 1.1 deraadt }
548 1.1 deraadt while (dent = readdir(d))
549 1.1 deraadt if (strncmp(dent->d_name, ipname, 8) == 0)
550 1.1 deraadt return 1;
551 1.1 deraadt return 0;
552 1.1 deraadt }
553 1.8 thorpej #endif /* REQUIRE_TFTPBOOT */
554 1.8 thorpej
555 1.1 deraadt /*
556 1.1 deraadt * Given a list of IP addresses, 'alist', return the first address that
557 1.1 deraadt * is on network 'net'; 'netmask' is a mask indicating the network portion
558 1.1 deraadt * of the address.
559 1.1 deraadt */
560 1.59 joerg static u_int32_t
561 1.45 wiz choose_ipaddr(u_int32_t **alist, u_int32_t net, u_int32_t netmask)
562 1.1 deraadt {
563 1.26 mrg
564 1.1 deraadt for (; *alist; ++alist) {
565 1.1 deraadt if ((**alist & netmask) == net)
566 1.1 deraadt return **alist;
567 1.1 deraadt }
568 1.1 deraadt return 0;
569 1.1 deraadt }
570 1.1 deraadt /*
571 1.1 deraadt * Answer the RARP request in 'pkt', on the interface 'ii'. 'pkt' has
572 1.1 deraadt * already been checked for validity. The reply is overlaid on the request.
573 1.1 deraadt */
574 1.59 joerg static void
575 1.45 wiz rarp_process(struct if_info *ii, u_char *pkt)
576 1.1 deraadt {
577 1.1 deraadt struct ether_header *ep;
578 1.1 deraadt struct hostent *hp;
579 1.30 fvdl u_int32_t target_ipaddr = 0;
580 1.18 lukem char ename[MAXHOSTNAMELEN + 1];
581 1.2 deraadt struct in_addr in;
582 1.1 deraadt
583 1.1 deraadt ep = (struct ether_header *) pkt;
584 1.1 deraadt
585 1.18 lukem if (ether_ntohost(ename, (struct ether_addr *)&ep->ether_shost) != 0) {
586 1.18 lukem debug("no IP address for %s",
587 1.18 lukem ether_ntoa((struct ether_addr *)&ep->ether_shost));
588 1.1 deraadt return;
589 1.18 lukem }
590 1.18 lukem ename[sizeof(ename)-1] = '\0';
591 1.18 lukem
592 1.18 lukem if ((hp = gethostbyname(ename)) == 0) {
593 1.18 lukem debug("gethostbyname(%s) failed: %s", ename,
594 1.18 lukem hstrerror(h_errno));
595 1.18 lukem return;
596 1.18 lukem }
597 1.1 deraadt
598 1.1 deraadt /* Choose correct address from list. */
599 1.1 deraadt if (hp->h_addrtype != AF_INET) {
600 1.19 lukem rarperr(FATAL, "cannot handle non IP addresses");
601 1.1 deraadt /* NOTREACHED */
602 1.1 deraadt }
603 1.32 thorpej for (;; ii = ii->ii_alias) {
604 1.29 matt target_ipaddr = choose_ipaddr((u_int32_t **) hp->h_addr_list,
605 1.29 matt ii->ii_ipaddr & ii->ii_netmask, ii->ii_netmask);
606 1.29 matt if (target_ipaddr != 0)
607 1.29 matt break;
608 1.32 thorpej if (ii->ii_alias == NULL)
609 1.32 thorpej break;
610 1.29 matt }
611 1.1 deraadt
612 1.1 deraadt if (target_ipaddr == 0) {
613 1.2 deraadt in.s_addr = ii->ii_ipaddr & ii->ii_netmask;
614 1.28 mrg rarperr(NONFATAL, "cannot find %s on net %s",
615 1.2 deraadt ename, inet_ntoa(in));
616 1.1 deraadt return;
617 1.1 deraadt }
618 1.8 thorpej #ifdef REQUIRE_TFTPBOOT
619 1.1 deraadt if (rarp_bootable(htonl(target_ipaddr)))
620 1.8 thorpej #endif
621 1.24 mrg rarp_reply(ii, ep, target_ipaddr, hp);
622 1.18 lukem #ifdef REQUIRE_TFTPBOOT
623 1.18 lukem else
624 1.18 lukem debug("%08X not bootable", htonl(target_ipaddr));
625 1.18 lukem #endif
626 1.1 deraadt }
627 1.1 deraadt /*
628 1.1 deraadt * Lookup the ethernet address of the interface attached to the BPF
629 1.1 deraadt * file descriptor 'fd'; return it in 'eaddr'.
630 1.1 deraadt */
631 1.59 joerg static void
632 1.45 wiz lookup_eaddr(char *ifname, u_char *eaddr)
633 1.1 deraadt {
634 1.37 itojun struct ifaddrs *ifap, *ifa;
635 1.37 itojun struct sockaddr_dl *sdl;
636 1.37 itojun
637 1.37 itojun if (getifaddrs(&ifap) != 0) {
638 1.37 itojun rarperr(FATAL, "getifaddrs: %s", strerror(errno));
639 1.37 itojun /* NOTREACHED */
640 1.37 itojun }
641 1.37 itojun
642 1.37 itojun for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
643 1.37 itojun sdl = (struct sockaddr_dl *)ifa->ifa_addr;
644 1.37 itojun if (sdl->sdl_family != AF_LINK || sdl->sdl_type != IFT_ETHER ||
645 1.37 itojun sdl->sdl_alen != 6)
646 1.37 itojun continue;
647 1.37 itojun if (!strcmp(ifa->ifa_name, ifname)) {
648 1.37 itojun memmove((caddr_t)eaddr, (caddr_t)LLADDR(sdl), 6);
649 1.37 itojun debug("%s: %x:%x:%x:%x:%x:%x",
650 1.37 itojun ifa->ifa_name, eaddr[0], eaddr[1],
651 1.37 itojun eaddr[2], eaddr[3], eaddr[4], eaddr[5]);
652 1.37 itojun freeifaddrs(ifap);
653 1.37 itojun return;
654 1.37 itojun }
655 1.37 itojun }
656 1.37 itojun rarperr(FATAL, "lookup_eaddr: Never saw interface `%s'!", ifname);
657 1.37 itojun freeifaddrs(ifap);
658 1.1 deraadt }
659 1.1 deraadt /*
660 1.1 deraadt * Lookup the IP address and network mask of the interface named 'ifname'.
661 1.1 deraadt */
662 1.59 joerg static void
663 1.45 wiz lookup_ipaddr(char *ifname, u_int32_t *addrp, u_int32_t *netmaskp)
664 1.1 deraadt {
665 1.1 deraadt int fd;
666 1.1 deraadt
667 1.1 deraadt /* Use datagram socket to get IP address. */
668 1.1 deraadt if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
669 1.19 lukem rarperr(FATAL, "socket: %s", strerror(errno));
670 1.1 deraadt /* NOTREACHED */
671 1.1 deraadt }
672 1.29 matt if (*addrp == INADDR_ANY) {
673 1.29 matt struct ifreq ifr;
674 1.29 matt memset(&ifr, 0, sizeof(ifr));
675 1.29 matt (void)strncpy(ifr.ifr_name, ifname, sizeof ifr.ifr_name);
676 1.29 matt if (ioctl(fd, SIOCGIFADDR, (char *) &ifr) < 0) {
677 1.29 matt rarperr(FATAL, "SIOCGIFADDR: %s", strerror(errno));
678 1.29 matt /* NOTREACHED */
679 1.29 matt }
680 1.29 matt *addrp = ((struct sockaddr_in *) & ifr.ifr_addr)->sin_addr.s_addr;
681 1.29 matt if (ioctl(fd, SIOCGIFNETMASK, (char *) &ifr) < 0) {
682 1.29 matt perror("SIOCGIFNETMASK");
683 1.29 matt exit(1);
684 1.29 matt }
685 1.29 matt *netmaskp = ((struct sockaddr_in *) & ifr.ifr_addr)->sin_addr.s_addr;
686 1.29 matt } else {
687 1.29 matt struct ifaliasreq ifra;
688 1.29 matt memset(&ifra, 0, sizeof(ifra));
689 1.29 matt (void)strncpy(ifra.ifra_name, ifname, sizeof ifra.ifra_name);
690 1.29 matt ((struct sockaddr_in *) & ifra.ifra_addr)->sin_family = AF_INET;
691 1.29 matt ((struct sockaddr_in *) & ifra.ifra_addr)->sin_addr.s_addr = *addrp;
692 1.29 matt if (ioctl(fd, SIOCGIFALIAS, (char *) &ifra) < 0) {
693 1.29 matt rarperr(FATAL, "SIOCGIFALIAS: %s", strerror(errno));
694 1.29 matt /* NOTREACHED */
695 1.29 matt }
696 1.29 matt *addrp = ((struct sockaddr_in *) & ifra.ifra_addr)->sin_addr.s_addr;
697 1.29 matt *netmaskp = ((struct sockaddr_in *) & ifra.ifra_mask)->sin_addr.s_addr;
698 1.1 deraadt }
699 1.1 deraadt /* If SIOCGIFNETMASK didn't work, figure out a mask from the IP
700 1.1 deraadt * address class. */
701 1.1 deraadt if (*netmaskp == 0)
702 1.1 deraadt *netmaskp = ipaddrtonetmask(*addrp);
703 1.1 deraadt
704 1.26 mrg (void)close(fd);
705 1.1 deraadt }
706 1.1 deraadt /*
707 1.1 deraadt * Poke the kernel arp tables with the ethernet/ip address combinataion
708 1.1 deraadt * given. When processing a reply, we must do this so that the booting
709 1.1 deraadt * host (i.e. the guy running rarpd), won't try to ARP for the hardware
710 1.1 deraadt * address of the guy being booted (he cannot answer the ARP).
711 1.1 deraadt */
712 1.22 is #ifndef __NetBSD__
713 1.59 joerg static void
714 1.45 wiz update_arptab(u_char *ep, u_int32_t ipaddr)
715 1.1 deraadt {
716 1.1 deraadt struct arpreq request;
717 1.1 deraadt struct sockaddr_in *sin;
718 1.1 deraadt
719 1.1 deraadt request.arp_flags = 0;
720 1.1 deraadt sin = (struct sockaddr_in *) & request.arp_pa;
721 1.1 deraadt sin->sin_family = AF_INET;
722 1.1 deraadt sin->sin_addr.s_addr = ipaddr;
723 1.1 deraadt request.arp_ha.sa_family = AF_UNSPEC;
724 1.1 deraadt /* This is needed #if defined(COMPAT_43) && BYTE_ORDER != BIG_ENDIAN,
725 1.1 deraadt because AF_UNSPEC is zero and the kernel assumes that a zero
726 1.1 deraadt sa_family means that the real sa_family value is in sa_len. */
727 1.1 deraadt request.arp_ha.sa_len = 16; /* XXX */
728 1.21 lukem memmove((char *) request.arp_ha.sa_data, (char *)ep, 6);
729 1.1 deraadt
730 1.7 mycroft #if 0
731 1.1 deraadt s = socket(AF_INET, SOCK_DGRAM, 0);
732 1.1 deraadt if (ioctl(s, SIOCSARP, (caddr_t) & request) < 0) {
733 1.19 lukem rarperr(NONFATAL, "SIOCSARP: %s", strerror(errno));
734 1.1 deraadt }
735 1.26 mrg (void)close(s);
736 1.7 mycroft #endif
737 1.1 deraadt }
738 1.22 is #endif
739 1.22 is
740 1.1 deraadt /*
741 1.1 deraadt * Build a reverse ARP packet and sent it out on the interface.
742 1.6 cgd * 'ep' points to a valid ARPOP_REVREQUEST. The ARPOP_REVREPLY is built
743 1.1 deraadt * on top of the request, then written to the network.
744 1.1 deraadt *
745 1.1 deraadt * RFC 903 defines the ether_arp fields as follows. The following comments
746 1.1 deraadt * are taken (more or less) straight from this document.
747 1.1 deraadt *
748 1.6 cgd * ARPOP_REVREQUEST
749 1.1 deraadt *
750 1.1 deraadt * arp_sha is the hardware address of the sender of the packet.
751 1.1 deraadt * arp_spa is undefined.
752 1.1 deraadt * arp_tha is the 'target' hardware address.
753 1.1 deraadt * In the case where the sender wishes to determine his own
754 1.1 deraadt * protocol address, this, like arp_sha, will be the hardware
755 1.1 deraadt * address of the sender.
756 1.1 deraadt * arp_tpa is undefined.
757 1.1 deraadt *
758 1.6 cgd * ARPOP_REVREPLY
759 1.1 deraadt *
760 1.1 deraadt * arp_sha is the hardware address of the responder (the sender of the
761 1.1 deraadt * reply packet).
762 1.1 deraadt * arp_spa is the protocol address of the responder (see the note below).
763 1.1 deraadt * arp_tha is the hardware address of the target, and should be the same as
764 1.1 deraadt * that which was given in the request.
765 1.1 deraadt * arp_tpa is the protocol address of the target, that is, the desired address.
766 1.1 deraadt *
767 1.1 deraadt * Note that the requirement that arp_spa be filled in with the responder's
768 1.1 deraadt * protocol is purely for convenience. For instance, if a system were to use
769 1.1 deraadt * both ARP and RARP, then the inclusion of the valid protocol-hardware
770 1.1 deraadt * address pair (arp_spa, arp_sha) may eliminate the need for a subsequent
771 1.1 deraadt * ARP request.
772 1.1 deraadt */
773 1.59 joerg static void
774 1.45 wiz rarp_reply(struct if_info *ii, struct ether_header *ep, u_int32_t ipaddr,
775 1.45 wiz struct hostent *hp)
776 1.1 deraadt {
777 1.1 deraadt int n;
778 1.16 is #ifdef __NetBSD__
779 1.16 is struct arphdr *ap = (struct arphdr *) (ep + 1);
780 1.16 is #else
781 1.1 deraadt struct ether_arp *ap = (struct ether_arp *) (ep + 1);
782 1.16 is #endif
783 1.16 is
784 1.1 deraadt int len;
785 1.1 deraadt
786 1.16 is #ifdef __NetBSD__
787 1.55 mrg (void)mkarp((u_int8_t *)ar_sha(ap), ipaddr);
788 1.16 is #else
789 1.1 deraadt update_arptab((u_char *) & ap->arp_sha, ipaddr);
790 1.16 is #endif
791 1.1 deraadt
792 1.1 deraadt /* Build the rarp reply by modifying the rarp request in place. */
793 1.11 mycroft #ifdef __FreeBSD__
794 1.11 mycroft /* BPF (incorrectly) wants this in host order. */
795 1.11 mycroft ep->ether_type = ETHERTYPE_REVARP;
796 1.11 mycroft #else
797 1.3 deraadt ep->ether_type = htons(ETHERTYPE_REVARP);
798 1.11 mycroft #endif
799 1.16 is #ifdef __NetBSD__
800 1.16 is ap->ar_hrd = htons(ARPHRD_ETHER);
801 1.16 is ap->ar_pro = htons(ETHERTYPE_IP);
802 1.16 is ap->ar_op = htons(ARPOP_REVREPLY);
803 1.16 is
804 1.21 lukem memmove((char *) &ep->ether_dhost, ar_sha(ap), 6);
805 1.21 lukem memmove((char *) &ep->ether_shost, (char *) ii->ii_eaddr, 6);
806 1.21 lukem memmove(ar_sha(ap), (char *) ii->ii_eaddr, 6);
807 1.16 is
808 1.21 lukem memmove(ar_tpa(ap), (char *) &ipaddr, 4);
809 1.16 is /* Target hardware is unchanged. */
810 1.21 lukem memmove(ar_spa(ap), (char *) &ii->ii_ipaddr, 4);
811 1.16 is
812 1.16 is len = sizeof(*ep) + sizeof(*ap) +
813 1.16 is 2 * ap->ar_pln + 2 * ap->ar_hln;
814 1.16 is #else
815 1.4 cgd ap->ea_hdr.ar_hrd = htons(ARPHRD_ETHER);
816 1.4 cgd ap->ea_hdr.ar_pro = htons(ETHERTYPE_IP);
817 1.6 cgd ap->arp_op = htons(ARPOP_REVREPLY);
818 1.1 deraadt
819 1.21 lukem memmove((char *) &ep->ether_dhost, (char *) &ap->arp_sha, 6);
820 1.21 lukem memmove((char *) &ep->ether_shost, (char *) ii->ii_eaddr, 6);
821 1.21 lukem memmove((char *) &ap->arp_sha, (char *) ii->ii_eaddr, 6);
822 1.1 deraadt
823 1.21 lukem memmove((char *) ap->arp_tpa, (char *) &ipaddr, 4);
824 1.1 deraadt /* Target hardware is unchanged. */
825 1.21 lukem memmove((char *) ap->arp_spa, (char *) &ii->ii_ipaddr, 4);
826 1.1 deraadt
827 1.1 deraadt len = sizeof(*ep) + sizeof(*ap);
828 1.16 is #endif
829 1.16 is
830 1.40 is debug("%s asked; %s replied",
831 1.40 is ether_ntoa((struct ether_addr *)ar_tha(ap)), hp->h_name);
832 1.24 mrg if (lflag)
833 1.40 is syslog(LOG_INFO, "%s asked; %s replied",
834 1.40 is ether_ntoa((struct ether_addr *)ar_tha(ap)), hp->h_name);
835 1.1 deraadt n = write(ii->ii_fd, (char *) ep, len);
836 1.1 deraadt if (n != len) {
837 1.19 lukem rarperr(NONFATAL, "write: only %d of %d bytes written", n, len);
838 1.1 deraadt }
839 1.1 deraadt }
840 1.1 deraadt /*
841 1.1 deraadt * Get the netmask of an IP address. This routine is used if
842 1.1 deraadt * SIOCGIFNETMASK doesn't work.
843 1.1 deraadt */
844 1.59 joerg static u_int32_t
845 1.45 wiz ipaddrtonetmask(u_int32_t addr)
846 1.1 deraadt {
847 1.26 mrg
848 1.1 deraadt if (IN_CLASSA(addr))
849 1.1 deraadt return IN_CLASSA_NET;
850 1.1 deraadt if (IN_CLASSB(addr))
851 1.1 deraadt return IN_CLASSB_NET;
852 1.1 deraadt if (IN_CLASSC(addr))
853 1.1 deraadt return IN_CLASSC_NET;
854 1.19 lukem rarperr(FATAL, "unknown IP address class: %08X", addr);
855 1.1 deraadt /* NOTREACHED */
856 1.19 lukem return(-1);
857 1.1 deraadt }
858 1.1 deraadt
859 1.1 deraadt #include <stdarg.h>
860 1.1 deraadt
861 1.59 joerg static void
862 1.19 lukem rarperr(int fatal, const char *fmt,...)
863 1.1 deraadt {
864 1.1 deraadt va_list ap;
865 1.26 mrg
866 1.1 deraadt va_start(ap, fmt);
867 1.1 deraadt if (dflag) {
868 1.1 deraadt if (fatal)
869 1.53 christos (void)fprintf(stderr, "%s: error: ", getprogname());
870 1.1 deraadt else
871 1.53 christos (void)fprintf(stderr, "%s: warning: ", getprogname());
872 1.26 mrg (void)vfprintf(stderr, fmt, ap);
873 1.43 wiz va_end(ap);
874 1.43 wiz va_start(ap, fmt);
875 1.26 mrg (void)fprintf(stderr, "\n");
876 1.1 deraadt }
877 1.1 deraadt vsyslog(LOG_ERR, fmt, ap);
878 1.1 deraadt va_end(ap);
879 1.33 thorpej if (fatal)
880 1.1 deraadt exit(1);
881 1.1 deraadt /* NOTREACHED */
882 1.1 deraadt }
883 1.1 deraadt
884 1.59 joerg static void
885 1.1 deraadt debug(const char *fmt,...)
886 1.1 deraadt {
887 1.1 deraadt va_list ap;
888 1.1 deraadt
889 1.18 lukem va_start(ap, fmt);
890 1.18 lukem if (dflag) {
891 1.53 christos (void)fprintf(stderr, "%s: ", getprogname());
892 1.26 mrg (void)vfprintf(stderr, fmt, ap);
893 1.43 wiz va_end(ap);
894 1.43 wiz va_start(ap, fmt);
895 1.26 mrg (void)fprintf(stderr, "\n");
896 1.1 deraadt }
897 1.18 lukem vsyslog(LOG_WARNING, fmt, ap);
898 1.18 lukem va_end(ap);
899 1.1 deraadt }
900