xref: /freebsd/crypto/openssh/ssh-keyscan.c (revision a35d88931c87cfe6bd38f01d7bad22140b3b38f3) 
1 /*
2  * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
3  *
4  * Modification and redistribution in source and binary forms is
5  * permitted provided that due credit is given to the author and the
6  * OpenBSD project by leaving this copyright notice intact.
7  */
8 
9 #include "includes.h"
10 RCSID("$OpenBSD: ssh-keyscan.c,v 1.47 2004/03/08 09:38:05 djm Exp $");
11 
12 #include "openbsd-compat/sys-queue.h"
13 
14 #include <openssl/bn.h>
15 
16 #include <setjmp.h>
17 #include "xmalloc.h"
18 #include "ssh.h"
19 #include "ssh1.h"
20 #include "key.h"
21 #include "kex.h"
22 #include "compat.h"
23 #include "myproposal.h"
24 #include "packet.h"
25 #include "dispatch.h"
26 #include "buffer.h"
27 #include "bufaux.h"
28 #include "log.h"
29 #include "atomicio.h"
30 #include "misc.h"
31 
32 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
33    Default value is AF_UNSPEC means both IPv4 and IPv6. */
34 int IPv4or6 = AF_UNSPEC;
35 
36 int ssh_port = SSH_DEFAULT_PORT;
37 
38 #define KT_RSA1	1
39 #define KT_DSA	2
40 #define KT_RSA	4
41 
42 int get_keytypes = KT_RSA1;	/* Get only RSA1 keys by default */
43 
44 #define MAXMAXFD 256
45 
46 /* The number of seconds after which to give up on a TCP connection */
47 int timeout = 5;
48 
49 int maxfd;
50 #define MAXCON (maxfd - 10)
51 
52 #ifdef HAVE___PROGNAME
53 extern char *__progname;
54 #else
55 char *__progname;
56 #endif
57 fd_set *read_wait;
58 size_t read_wait_size;
59 int ncon;
60 int nonfatal_fatal = 0;
61 jmp_buf kexjmp;
62 Key *kexjmp_key;
63 
64 /*
65  * Keep a connection structure for each file descriptor.  The state
66  * associated with file descriptor n is held in fdcon[n].
67  */
68 typedef struct Connection {
69 	u_char c_status;	/* State of connection on this file desc. */
70 #define CS_UNUSED 0		/* File descriptor unused */
71 #define CS_CON 1		/* Waiting to connect/read greeting */
72 #define CS_SIZE 2		/* Waiting to read initial packet size */
73 #define CS_KEYS 3		/* Waiting to read public key packet */
74 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
75 	int c_plen;		/* Packet length field for ssh packet */
76 	int c_len;		/* Total bytes which must be read. */
77 	int c_off;		/* Length of data read so far. */
78 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
79 	char *c_namebase;	/* Address to free for c_name and c_namelist */
80 	char *c_name;		/* Hostname of connection for errors */
81 	char *c_namelist;	/* Pointer to other possible addresses */
82 	char *c_output_name;	/* Hostname of connection for output */
83 	char *c_data;		/* Data read from this fd */
84 	Kex *c_kex;		/* The key-exchange struct for ssh2 */
85 	struct timeval c_tv;	/* Time at which connection gets aborted */
86 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
87 } con;
88 
89 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
90 con *fdcon;
91 
92 /*
93  *  This is just a wrapper around fgets() to make it usable.
94  */
95 
96 /* Stress-test.  Increase this later. */
97 #define LINEBUF_SIZE 16
98 
99 typedef struct {
100 	char *buf;
101 	u_int size;
102 	int lineno;
103 	const char *filename;
104 	FILE *stream;
105 	void (*errfun) (const char *,...);
106 } Linebuf;
107 
108 static Linebuf *
109 Linebuf_alloc(const char *filename, void (*errfun) (const char *,...))
110 {
111 	Linebuf *lb;
112 
113 	if (!(lb = malloc(sizeof(*lb)))) {
114 		if (errfun)
115 			(*errfun) ("linebuf (%s): malloc failed\n",
116 			    filename ? filename : "(stdin)");
117 		return (NULL);
118 	}
119 	if (filename) {
120 		lb->filename = filename;
121 		if (!(lb->stream = fopen(filename, "r"))) {
122 			xfree(lb);
123 			if (errfun)
124 				(*errfun) ("%s: %s\n", filename, strerror(errno));
125 			return (NULL);
126 		}
127 	} else {
128 		lb->filename = "(stdin)";
129 		lb->stream = stdin;
130 	}
131 
132 	if (!(lb->buf = malloc(lb->size = LINEBUF_SIZE))) {
133 		if (errfun)
134 			(*errfun) ("linebuf (%s): malloc failed\n", lb->filename);
135 		xfree(lb);
136 		return (NULL);
137 	}
138 	lb->errfun = errfun;
139 	lb->lineno = 0;
140 	return (lb);
141 }
142 
143 static void
144 Linebuf_free(Linebuf * lb)
145 {
146 	fclose(lb->stream);
147 	xfree(lb->buf);
148 	xfree(lb);
149 }
150 
151 #if 0
152 static void
153 Linebuf_restart(Linebuf * lb)
154 {
155 	clearerr(lb->stream);
156 	rewind(lb->stream);
157 	lb->lineno = 0;
158 }
159 
160 static int
161 Linebuf_lineno(Linebuf * lb)
162 {
163 	return (lb->lineno);
164 }
165 #endif
166 
167 static char *
168 Linebuf_getline(Linebuf * lb)
169 {
170 	int n = 0;
171 	void *p;
172 
173 	lb->lineno++;
174 	for (;;) {
175 		/* Read a line */
176 		if (!fgets(&lb->buf[n], lb->size - n, lb->stream)) {
177 			if (ferror(lb->stream) && lb->errfun)
178 				(*lb->errfun)("%s: %s\n", lb->filename,
179 				    strerror(errno));
180 			return (NULL);
181 		}
182 		n = strlen(lb->buf);
183 
184 		/* Return it or an error if it fits */
185 		if (n > 0 && lb->buf[n - 1] == '\n') {
186 			lb->buf[n - 1] = '\0';
187 			return (lb->buf);
188 		}
189 		if (n != lb->size - 1) {
190 			if (lb->errfun)
191 				(*lb->errfun)("%s: skipping incomplete last line\n",
192 				    lb->filename);
193 			return (NULL);
194 		}
195 		/* Double the buffer if we need more space */
196 		lb->size *= 2;
197 		if ((p = realloc(lb->buf, lb->size)) == NULL) {
198 			lb->size /= 2;
199 			if (lb->errfun)
200 				(*lb->errfun)("linebuf (%s): realloc failed\n",
201 				    lb->filename);
202 			return (NULL);
203 		}
204 		lb->buf = p;
205 	}
206 }
207 
208 static int
209 fdlim_get(int hard)
210 {
211 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
212 	struct rlimit rlfd;
213 
214 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
215 		return (-1);
216 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
217 		return SSH_SYSFDMAX;
218 	else
219 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
220 #else
221 	return SSH_SYSFDMAX;
222 #endif
223 }
224 
225 static int
226 fdlim_set(int lim)
227 {
228 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
229 	struct rlimit rlfd;
230 #endif
231 
232 	if (lim <= 0)
233 		return (-1);
234 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
235 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
236 		return (-1);
237 	rlfd.rlim_cur = lim;
238 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
239 		return (-1);
240 #elif defined (HAVE_SETDTABLESIZE)
241 	setdtablesize(lim);
242 #endif
243 	return (0);
244 }
245 
246 /*
247  * This is an strsep function that returns a null field for adjacent
248  * separators.  This is the same as the 4.4BSD strsep, but different from the
249  * one in the GNU libc.
250  */
251 static char *
252 xstrsep(char **str, const char *delim)
253 {
254 	char *s, *e;
255 
256 	if (!**str)
257 		return (NULL);
258 
259 	s = *str;
260 	e = s + strcspn(s, delim);
261 
262 	if (*e != '\0')
263 		*e++ = '\0';
264 	*str = e;
265 
266 	return (s);
267 }
268 
269 /*
270  * Get the next non-null token (like GNU strsep).  Strsep() will return a
271  * null token for two adjacent separators, so we may have to loop.
272  */
273 static char *
274 strnnsep(char **stringp, char *delim)
275 {
276 	char *tok;
277 
278 	do {
279 		tok = xstrsep(stringp, delim);
280 	} while (tok && *tok == '\0');
281 	return (tok);
282 }
283 
284 static Key *
285 keygrab_ssh1(con *c)
286 {
287 	static Key *rsa;
288 	static Buffer msg;
289 
290 	if (rsa == NULL) {
291 		buffer_init(&msg);
292 		rsa = key_new(KEY_RSA1);
293 	}
294 	buffer_append(&msg, c->c_data, c->c_plen);
295 	buffer_consume(&msg, 8 - (c->c_plen & 7));	/* padding */
296 	if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
297 		error("%s: invalid packet type", c->c_name);
298 		buffer_clear(&msg);
299 		return NULL;
300 	}
301 	buffer_consume(&msg, 8);		/* cookie */
302 
303 	/* server key */
304 	(void) buffer_get_int(&msg);
305 	buffer_get_bignum(&msg, rsa->rsa->e);
306 	buffer_get_bignum(&msg, rsa->rsa->n);
307 
308 	/* host key */
309 	(void) buffer_get_int(&msg);
310 	buffer_get_bignum(&msg, rsa->rsa->e);
311 	buffer_get_bignum(&msg, rsa->rsa->n);
312 
313 	buffer_clear(&msg);
314 
315 	return (rsa);
316 }
317 
318 static int
319 hostjump(Key *hostkey)
320 {
321 	kexjmp_key = hostkey;
322 	longjmp(kexjmp, 1);
323 }
324 
325 static int
326 ssh2_capable(int remote_major, int remote_minor)
327 {
328 	switch (remote_major) {
329 	case 1:
330 		if (remote_minor == 99)
331 			return 1;
332 		break;
333 	case 2:
334 		return 1;
335 	default:
336 		break;
337 	}
338 	return 0;
339 }
340 
341 static Key *
342 keygrab_ssh2(con *c)
343 {
344 	int j;
345 
346 	packet_set_connection(c->c_fd, c->c_fd);
347 	enable_compat20();
348 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = c->c_keytype == KT_DSA?
349 	    "ssh-dss": "ssh-rsa";
350 	c->c_kex = kex_setup(myproposal);
351 	c->c_kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
352 	c->c_kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
353 	c->c_kex->verify_host_key = hostjump;
354 
355 	if (!(j = setjmp(kexjmp))) {
356 		nonfatal_fatal = 1;
357 		dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex);
358 		fprintf(stderr, "Impossible! dispatch_run() returned!\n");
359 		exit(1);
360 	}
361 	nonfatal_fatal = 0;
362 	xfree(c->c_kex);
363 	c->c_kex = NULL;
364 	packet_close();
365 
366 	return j < 0? NULL : kexjmp_key;
367 }
368 
369 static void
370 keyprint(con *c, Key *key)
371 {
372 	if (!key)
373 		return;
374 
375 	fprintf(stdout, "%s ", c->c_output_name ? c->c_output_name : c->c_name);
376 	key_write(key, stdout);
377 	fputs("\n", stdout);
378 }
379 
380 static int
381 tcpconnect(char *host)
382 {
383 	struct addrinfo hints, *ai, *aitop;
384 	char strport[NI_MAXSERV];
385 	int gaierr, s = -1;
386 
387 	snprintf(strport, sizeof strport, "%d", ssh_port);
388 	memset(&hints, 0, sizeof(hints));
389 	hints.ai_family = IPv4or6;
390 	hints.ai_socktype = SOCK_STREAM;
391 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
392 		fatal("getaddrinfo %s: %s", host, gai_strerror(gaierr));
393 	for (ai = aitop; ai; ai = ai->ai_next) {
394 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
395 		if (s < 0) {
396 			error("socket: %s", strerror(errno));
397 			continue;
398 		}
399 		if (fcntl(s, F_SETFL, O_NONBLOCK) < 0)
400 			fatal("F_SETFL: %s", strerror(errno));
401 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
402 		    errno != EINPROGRESS)
403 			error("connect (`%s'): %s", host, strerror(errno));
404 		else
405 			break;
406 		close(s);
407 		s = -1;
408 	}
409 	freeaddrinfo(aitop);
410 	return s;
411 }
412 
413 static int
414 conalloc(char *iname, char *oname, int keytype)
415 {
416 	char *namebase, *name, *namelist;
417 	int s;
418 
419 	namebase = namelist = xstrdup(iname);
420 
421 	do {
422 		name = xstrsep(&namelist, ",");
423 		if (!name) {
424 			xfree(namebase);
425 			return (-1);
426 		}
427 	} while ((s = tcpconnect(name)) < 0);
428 
429 	if (s >= maxfd)
430 		fatal("conalloc: fdno %d too high", s);
431 	if (fdcon[s].c_status)
432 		fatal("conalloc: attempt to reuse fdno %d", s);
433 
434 	fdcon[s].c_fd = s;
435 	fdcon[s].c_status = CS_CON;
436 	fdcon[s].c_namebase = namebase;
437 	fdcon[s].c_name = name;
438 	fdcon[s].c_namelist = namelist;
439 	fdcon[s].c_output_name = xstrdup(oname);
440 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
441 	fdcon[s].c_len = 4;
442 	fdcon[s].c_off = 0;
443 	fdcon[s].c_keytype = keytype;
444 	gettimeofday(&fdcon[s].c_tv, NULL);
445 	fdcon[s].c_tv.tv_sec += timeout;
446 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
447 	FD_SET(s, read_wait);
448 	ncon++;
449 	return (s);
450 }
451 
452 static void
453 confree(int s)
454 {
455 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
456 		fatal("confree: attempt to free bad fdno %d", s);
457 	close(s);
458 	xfree(fdcon[s].c_namebase);
459 	xfree(fdcon[s].c_output_name);
460 	if (fdcon[s].c_status == CS_KEYS)
461 		xfree(fdcon[s].c_data);
462 	fdcon[s].c_status = CS_UNUSED;
463 	fdcon[s].c_keytype = 0;
464 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
465 	FD_CLR(s, read_wait);
466 	ncon--;
467 }
468 
469 static void
470 contouch(int s)
471 {
472 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
473 	gettimeofday(&fdcon[s].c_tv, NULL);
474 	fdcon[s].c_tv.tv_sec += timeout;
475 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
476 }
477 
478 static int
479 conrecycle(int s)
480 {
481 	con *c = &fdcon[s];
482 	int ret;
483 
484 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
485 	confree(s);
486 	return (ret);
487 }
488 
489 static void
490 congreet(int s)
491 {
492 	int remote_major = 0, remote_minor = 0, n = 0;
493 	char buf[256], *cp;
494 	char remote_version[sizeof buf];
495 	size_t bufsiz;
496 	con *c = &fdcon[s];
497 
498 	bufsiz = sizeof(buf);
499 	cp = buf;
500 	while (bufsiz-- && (n = read(s, cp, 1)) == 1 && *cp != '\n') {
501 		if (*cp == '\r')
502 			*cp = '\n';
503 		cp++;
504 	}
505 	if (n < 0) {
506 		if (errno != ECONNREFUSED)
507 			error("read (%s): %s", c->c_name, strerror(errno));
508 		conrecycle(s);
509 		return;
510 	}
511 	if (n == 0) {
512 		error("%s: Connection closed by remote host", c->c_name);
513 		conrecycle(s);
514 		return;
515 	}
516 	if (*cp != '\n' && *cp != '\r') {
517 		error("%s: bad greeting", c->c_name);
518 		confree(s);
519 		return;
520 	}
521 	*cp = '\0';
522 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
523 	    &remote_major, &remote_minor, remote_version) == 3)
524 		compat_datafellows(remote_version);
525 	else
526 		datafellows = 0;
527 	if (c->c_keytype != KT_RSA1) {
528 		if (!ssh2_capable(remote_major, remote_minor)) {
529 			debug("%s doesn't support ssh2", c->c_name);
530 			confree(s);
531 			return;
532 		}
533 	} else if (remote_major != 1) {
534 		debug("%s doesn't support ssh1", c->c_name);
535 		confree(s);
536 		return;
537 	}
538 	fprintf(stderr, "# %s %s\n", c->c_name, chop(buf));
539 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
540 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
541 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
542 	if (atomicio(vwrite, s, buf, n) != n) {
543 		error("write (%s): %s", c->c_name, strerror(errno));
544 		confree(s);
545 		return;
546 	}
547 	if (c->c_keytype != KT_RSA1) {
548 		keyprint(c, keygrab_ssh2(c));
549 		confree(s);
550 		return;
551 	}
552 	c->c_status = CS_SIZE;
553 	contouch(s);
554 }
555 
556 static void
557 conread(int s)
558 {
559 	con *c = &fdcon[s];
560 	int n;
561 
562 	if (c->c_status == CS_CON) {
563 		congreet(s);
564 		return;
565 	}
566 	n = read(s, c->c_data + c->c_off, c->c_len - c->c_off);
567 	if (n < 0) {
568 		error("read (%s): %s", c->c_name, strerror(errno));
569 		confree(s);
570 		return;
571 	}
572 	c->c_off += n;
573 
574 	if (c->c_off == c->c_len)
575 		switch (c->c_status) {
576 		case CS_SIZE:
577 			c->c_plen = htonl(c->c_plen);
578 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
579 			c->c_off = 0;
580 			c->c_data = xmalloc(c->c_len);
581 			c->c_status = CS_KEYS;
582 			break;
583 		case CS_KEYS:
584 			keyprint(c, keygrab_ssh1(c));
585 			confree(s);
586 			return;
587 			break;
588 		default:
589 			fatal("conread: invalid status %d", c->c_status);
590 			break;
591 		}
592 
593 	contouch(s);
594 }
595 
596 static void
597 conloop(void)
598 {
599 	struct timeval seltime, now;
600 	fd_set *r, *e;
601 	con *c;
602 	int i;
603 
604 	gettimeofday(&now, NULL);
605 	c = TAILQ_FIRST(&tq);
606 
607 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
608 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
609 		seltime = c->c_tv;
610 		seltime.tv_sec -= now.tv_sec;
611 		seltime.tv_usec -= now.tv_usec;
612 		if (seltime.tv_usec < 0) {
613 			seltime.tv_usec += 1000000;
614 			seltime.tv_sec--;
615 		}
616 	} else
617 		seltime.tv_sec = seltime.tv_usec = 0;
618 
619 	r = xmalloc(read_wait_size);
620 	memcpy(r, read_wait, read_wait_size);
621 	e = xmalloc(read_wait_size);
622 	memcpy(e, read_wait, read_wait_size);
623 
624 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
625 	    (errno == EAGAIN || errno == EINTR))
626 		;
627 
628 	for (i = 0; i < maxfd; i++) {
629 		if (FD_ISSET(i, e)) {
630 			error("%s: exception!", fdcon[i].c_name);
631 			confree(i);
632 		} else if (FD_ISSET(i, r))
633 			conread(i);
634 	}
635 	xfree(r);
636 	xfree(e);
637 
638 	c = TAILQ_FIRST(&tq);
639 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
640 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
641 		int s = c->c_fd;
642 
643 		c = TAILQ_NEXT(c, c_link);
644 		conrecycle(s);
645 	}
646 }
647 
648 static void
649 do_host(char *host)
650 {
651 	char *name = strnnsep(&host, " \t\n");
652 	int j;
653 
654 	if (name == NULL)
655 		return;
656 	for (j = KT_RSA1; j <= KT_RSA; j *= 2) {
657 		if (get_keytypes & j) {
658 			while (ncon >= MAXCON)
659 				conloop();
660 			conalloc(name, *host ? host : name, j);
661 		}
662 	}
663 }
664 
665 void
666 fatal(const char *fmt,...)
667 {
668 	va_list args;
669 
670 	va_start(args, fmt);
671 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
672 	va_end(args);
673 	if (nonfatal_fatal)
674 		longjmp(kexjmp, -1);
675 	else
676 		exit(255);
677 }
678 
679 static void
680 usage(void)
681 {
682 	fprintf(stderr, "usage: %s [-v46] [-p port] [-T timeout] [-t type] [-f file]\n"
683 	    "\t\t   [host | addrlist namelist] [...]\n",
684 	    __progname);
685 	exit(1);
686 }
687 
688 int
689 main(int argc, char **argv)
690 {
691 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
692 	int opt, fopt_count = 0;
693 	char *tname;
694 
695 	extern int optind;
696 	extern char *optarg;
697 
698 	__progname = ssh_get_progname(argv[0]);
699 	init_rng();
700 	seed_rng();
701 	TAILQ_INIT(&tq);
702 
703 	if (argc <= 1)
704 		usage();
705 
706 	while ((opt = getopt(argc, argv, "v46p:T:t:f:")) != -1) {
707 		switch (opt) {
708 		case 'p':
709 			ssh_port = a2port(optarg);
710 			if (ssh_port == 0) {
711 				fprintf(stderr, "Bad port '%s'\n", optarg);
712 				exit(1);
713 			}
714 			break;
715 		case 'T':
716 			timeout = convtime(optarg);
717 			if (timeout == -1 || timeout == 0) {
718 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
719 				usage();
720 			}
721 			break;
722 		case 'v':
723 			if (!debug_flag) {
724 				debug_flag = 1;
725 				log_level = SYSLOG_LEVEL_DEBUG1;
726 			}
727 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
728 				log_level++;
729 			else
730 				fatal("Too high debugging level.");
731 			break;
732 		case 'f':
733 			if (strcmp(optarg, "-") == 0)
734 				optarg = NULL;
735 			argv[fopt_count++] = optarg;
736 			break;
737 		case 't':
738 			get_keytypes = 0;
739 			tname = strtok(optarg, ",");
740 			while (tname) {
741 				int type = key_type_from_name(tname);
742 				switch (type) {
743 				case KEY_RSA1:
744 					get_keytypes |= KT_RSA1;
745 					break;
746 				case KEY_DSA:
747 					get_keytypes |= KT_DSA;
748 					break;
749 				case KEY_RSA:
750 					get_keytypes |= KT_RSA;
751 					break;
752 				case KEY_UNSPEC:
753 					fatal("unknown key type %s", tname);
754 				}
755 				tname = strtok(NULL, ",");
756 			}
757 			break;
758 		case '4':
759 			IPv4or6 = AF_INET;
760 			break;
761 		case '6':
762 			IPv4or6 = AF_INET6;
763 			break;
764 		case '?':
765 		default:
766 			usage();
767 		}
768 	}
769 	if (optind == argc && !fopt_count)
770 		usage();
771 
772 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
773 
774 	maxfd = fdlim_get(1);
775 	if (maxfd < 0)
776 		fatal("%s: fdlim_get: bad value", __progname);
777 	if (maxfd > MAXMAXFD)
778 		maxfd = MAXMAXFD;
779 	if (MAXCON <= 0)
780 		fatal("%s: not enough file descriptors", __progname);
781 	if (maxfd > fdlim_get(0))
782 		fdlim_set(maxfd);
783 	fdcon = xmalloc(maxfd * sizeof(con));
784 	memset(fdcon, 0, maxfd * sizeof(con));
785 
786 	read_wait_size = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
787 	read_wait = xmalloc(read_wait_size);
788 	memset(read_wait, 0, read_wait_size);
789 
790 	if (fopt_count) {
791 		Linebuf *lb;
792 		char *line;
793 		int j;
794 
795 		for (j = 0; j < fopt_count; j++) {
796 			lb = Linebuf_alloc(argv[j], error);
797 			if (!lb)
798 				continue;
799 			while ((line = Linebuf_getline(lb)) != NULL)
800 				do_host(line);
801 			Linebuf_free(lb);
802 		}
803 	}
804 
805 	while (optind < argc)
806 		do_host(argv[optind++]);
807 
808 	while (ncon > 0)
809 		conloop();
810 
811 	return (0);
812 }
813