xref: /freebsd/crypto/openssh/ssh-keyscan.c (revision 6b806d21d144c25f4fad714e1c0cf780f5e27d7e) 
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 1.50 2004/08/11 21:44:32 avsm 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 extern char *__progname;
53 fd_set *read_wait;
54 size_t read_wait_size;
55 int ncon;
56 int nonfatal_fatal = 0;
57 jmp_buf kexjmp;
58 Key *kexjmp_key;
59 
60 /*
61  * Keep a connection structure for each file descriptor.  The state
62  * associated with file descriptor n is held in fdcon[n].
63  */
64 typedef struct Connection {
65 	u_char c_status;	/* State of connection on this file desc. */
66 #define CS_UNUSED 0		/* File descriptor unused */
67 #define CS_CON 1		/* Waiting to connect/read greeting */
68 #define CS_SIZE 2		/* Waiting to read initial packet size */
69 #define CS_KEYS 3		/* Waiting to read public key packet */
70 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
71 	int c_plen;		/* Packet length field for ssh packet */
72 	int c_len;		/* Total bytes which must be read. */
73 	int c_off;		/* Length of data read so far. */
74 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
75 	char *c_namebase;	/* Address to free for c_name and c_namelist */
76 	char *c_name;		/* Hostname of connection for errors */
77 	char *c_namelist;	/* Pointer to other possible addresses */
78 	char *c_output_name;	/* Hostname of connection for output */
79 	char *c_data;		/* Data read from this fd */
80 	Kex *c_kex;		/* The key-exchange struct for ssh2 */
81 	struct timeval c_tv;	/* Time at which connection gets aborted */
82 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
83 } con;
84 
85 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
86 con *fdcon;
87 
88 /*
89  *  This is just a wrapper around fgets() to make it usable.
90  */
91 
92 /* Stress-test.  Increase this later. */
93 #define LINEBUF_SIZE 16
94 
95 typedef struct {
96 	char *buf;
97 	u_int size;
98 	int lineno;
99 	const char *filename;
100 	FILE *stream;
101 	void (*errfun) (const char *,...);
102 } Linebuf;
103 
104 static Linebuf *
105 Linebuf_alloc(const char *filename, void (*errfun) (const char *,...))
106 {
107 	Linebuf *lb;
108 
109 	if (!(lb = malloc(sizeof(*lb)))) {
110 		if (errfun)
111 			(*errfun) ("linebuf (%s): malloc failed\n",
112 			    filename ? filename : "(stdin)");
113 		return (NULL);
114 	}
115 	if (filename) {
116 		lb->filename = filename;
117 		if (!(lb->stream = fopen(filename, "r"))) {
118 			xfree(lb);
119 			if (errfun)
120 				(*errfun) ("%s: %s\n", filename, strerror(errno));
121 			return (NULL);
122 		}
123 	} else {
124 		lb->filename = "(stdin)";
125 		lb->stream = stdin;
126 	}
127 
128 	if (!(lb->buf = malloc(lb->size = LINEBUF_SIZE))) {
129 		if (errfun)
130 			(*errfun) ("linebuf (%s): malloc failed\n", lb->filename);
131 		xfree(lb);
132 		return (NULL);
133 	}
134 	lb->errfun = errfun;
135 	lb->lineno = 0;
136 	return (lb);
137 }
138 
139 static void
140 Linebuf_free(Linebuf * lb)
141 {
142 	fclose(lb->stream);
143 	xfree(lb->buf);
144 	xfree(lb);
145 }
146 
147 #if 0
148 static void
149 Linebuf_restart(Linebuf * lb)
150 {
151 	clearerr(lb->stream);
152 	rewind(lb->stream);
153 	lb->lineno = 0;
154 }
155 
156 static int
157 Linebuf_lineno(Linebuf * lb)
158 {
159 	return (lb->lineno);
160 }
161 #endif
162 
163 static char *
164 Linebuf_getline(Linebuf * lb)
165 {
166 	int n = 0;
167 	void *p;
168 
169 	lb->lineno++;
170 	for (;;) {
171 		/* Read a line */
172 		if (!fgets(&lb->buf[n], lb->size - n, lb->stream)) {
173 			if (ferror(lb->stream) && lb->errfun)
174 				(*lb->errfun)("%s: %s\n", lb->filename,
175 				    strerror(errno));
176 			return (NULL);
177 		}
178 		n = strlen(lb->buf);
179 
180 		/* Return it or an error if it fits */
181 		if (n > 0 && lb->buf[n - 1] == '\n') {
182 			lb->buf[n - 1] = '\0';
183 			return (lb->buf);
184 		}
185 		if (n != lb->size - 1) {
186 			if (lb->errfun)
187 				(*lb->errfun)("%s: skipping incomplete last line\n",
188 				    lb->filename);
189 			return (NULL);
190 		}
191 		/* Double the buffer if we need more space */
192 		lb->size *= 2;
193 		if ((p = realloc(lb->buf, lb->size)) == NULL) {
194 			lb->size /= 2;
195 			if (lb->errfun)
196 				(*lb->errfun)("linebuf (%s): realloc failed\n",
197 				    lb->filename);
198 			return (NULL);
199 		}
200 		lb->buf = p;
201 	}
202 }
203 
204 static int
205 fdlim_get(int hard)
206 {
207 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
208 	struct rlimit rlfd;
209 
210 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
211 		return (-1);
212 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
213 		return SSH_SYSFDMAX;
214 	else
215 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
216 #else
217 	return SSH_SYSFDMAX;
218 #endif
219 }
220 
221 static int
222 fdlim_set(int lim)
223 {
224 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
225 	struct rlimit rlfd;
226 #endif
227 
228 	if (lim <= 0)
229 		return (-1);
230 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
231 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
232 		return (-1);
233 	rlfd.rlim_cur = lim;
234 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
235 		return (-1);
236 #elif defined (HAVE_SETDTABLESIZE)
237 	setdtablesize(lim);
238 #endif
239 	return (0);
240 }
241 
242 /*
243  * This is an strsep function that returns a null field for adjacent
244  * separators.  This is the same as the 4.4BSD strsep, but different from the
245  * one in the GNU libc.
246  */
247 static char *
248 xstrsep(char **str, const char *delim)
249 {
250 	char *s, *e;
251 
252 	if (!**str)
253 		return (NULL);
254 
255 	s = *str;
256 	e = s + strcspn(s, delim);
257 
258 	if (*e != '\0')
259 		*e++ = '\0';
260 	*str = e;
261 
262 	return (s);
263 }
264 
265 /*
266  * Get the next non-null token (like GNU strsep).  Strsep() will return a
267  * null token for two adjacent separators, so we may have to loop.
268  */
269 static char *
270 strnnsep(char **stringp, char *delim)
271 {
272 	char *tok;
273 
274 	do {
275 		tok = xstrsep(stringp, delim);
276 	} while (tok && *tok == '\0');
277 	return (tok);
278 }
279 
280 static Key *
281 keygrab_ssh1(con *c)
282 {
283 	static Key *rsa;
284 	static Buffer msg;
285 
286 	if (rsa == NULL) {
287 		buffer_init(&msg);
288 		rsa = key_new(KEY_RSA1);
289 	}
290 	buffer_append(&msg, c->c_data, c->c_plen);
291 	buffer_consume(&msg, 8 - (c->c_plen & 7));	/* padding */
292 	if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
293 		error("%s: invalid packet type", c->c_name);
294 		buffer_clear(&msg);
295 		return NULL;
296 	}
297 	buffer_consume(&msg, 8);		/* cookie */
298 
299 	/* server key */
300 	(void) buffer_get_int(&msg);
301 	buffer_get_bignum(&msg, rsa->rsa->e);
302 	buffer_get_bignum(&msg, rsa->rsa->n);
303 
304 	/* host key */
305 	(void) buffer_get_int(&msg);
306 	buffer_get_bignum(&msg, rsa->rsa->e);
307 	buffer_get_bignum(&msg, rsa->rsa->n);
308 
309 	buffer_clear(&msg);
310 
311 	return (rsa);
312 }
313 
314 static int
315 hostjump(Key *hostkey)
316 {
317 	kexjmp_key = hostkey;
318 	longjmp(kexjmp, 1);
319 }
320 
321 static int
322 ssh2_capable(int remote_major, int remote_minor)
323 {
324 	switch (remote_major) {
325 	case 1:
326 		if (remote_minor == 99)
327 			return 1;
328 		break;
329 	case 2:
330 		return 1;
331 	default:
332 		break;
333 	}
334 	return 0;
335 }
336 
337 static Key *
338 keygrab_ssh2(con *c)
339 {
340 	int j;
341 
342 	packet_set_connection(c->c_fd, c->c_fd);
343 	enable_compat20();
344 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = c->c_keytype == KT_DSA?
345 	    "ssh-dss": "ssh-rsa";
346 	c->c_kex = kex_setup(myproposal);
347 	c->c_kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
348 	c->c_kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
349 	c->c_kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
350 	c->c_kex->verify_host_key = hostjump;
351 
352 	if (!(j = setjmp(kexjmp))) {
353 		nonfatal_fatal = 1;
354 		dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex);
355 		fprintf(stderr, "Impossible! dispatch_run() returned!\n");
356 		exit(1);
357 	}
358 	nonfatal_fatal = 0;
359 	xfree(c->c_kex);
360 	c->c_kex = NULL;
361 	packet_close();
362 
363 	return j < 0? NULL : kexjmp_key;
364 }
365 
366 static void
367 keyprint(con *c, Key *key)
368 {
369 	if (!key)
370 		return;
371 
372 	fprintf(stdout, "%s ", c->c_output_name ? c->c_output_name : c->c_name);
373 	key_write(key, stdout);
374 	fputs("\n", stdout);
375 }
376 
377 static int
378 tcpconnect(char *host)
379 {
380 	struct addrinfo hints, *ai, *aitop;
381 	char strport[NI_MAXSERV];
382 	int gaierr, s = -1;
383 
384 	snprintf(strport, sizeof strport, "%d", ssh_port);
385 	memset(&hints, 0, sizeof(hints));
386 	hints.ai_family = IPv4or6;
387 	hints.ai_socktype = SOCK_STREAM;
388 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
389 		fatal("getaddrinfo %s: %s", host, gai_strerror(gaierr));
390 	for (ai = aitop; ai; ai = ai->ai_next) {
391 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
392 		if (s < 0) {
393 			error("socket: %s", strerror(errno));
394 			continue;
395 		}
396 		if (set_nonblock(s) == -1)
397 			fatal("%s: set_nonblock(%d)", __func__, s);
398 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
399 		    errno != EINPROGRESS)
400 			error("connect (`%s'): %s", host, strerror(errno));
401 		else
402 			break;
403 		close(s);
404 		s = -1;
405 	}
406 	freeaddrinfo(aitop);
407 	return s;
408 }
409 
410 static int
411 conalloc(char *iname, char *oname, int keytype)
412 {
413 	char *namebase, *name, *namelist;
414 	int s;
415 
416 	namebase = namelist = xstrdup(iname);
417 
418 	do {
419 		name = xstrsep(&namelist, ",");
420 		if (!name) {
421 			xfree(namebase);
422 			return (-1);
423 		}
424 	} while ((s = tcpconnect(name)) < 0);
425 
426 	if (s >= maxfd)
427 		fatal("conalloc: fdno %d too high", s);
428 	if (fdcon[s].c_status)
429 		fatal("conalloc: attempt to reuse fdno %d", s);
430 
431 	fdcon[s].c_fd = s;
432 	fdcon[s].c_status = CS_CON;
433 	fdcon[s].c_namebase = namebase;
434 	fdcon[s].c_name = name;
435 	fdcon[s].c_namelist = namelist;
436 	fdcon[s].c_output_name = xstrdup(oname);
437 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
438 	fdcon[s].c_len = 4;
439 	fdcon[s].c_off = 0;
440 	fdcon[s].c_keytype = keytype;
441 	gettimeofday(&fdcon[s].c_tv, NULL);
442 	fdcon[s].c_tv.tv_sec += timeout;
443 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
444 	FD_SET(s, read_wait);
445 	ncon++;
446 	return (s);
447 }
448 
449 static void
450 confree(int s)
451 {
452 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
453 		fatal("confree: attempt to free bad fdno %d", s);
454 	close(s);
455 	xfree(fdcon[s].c_namebase);
456 	xfree(fdcon[s].c_output_name);
457 	if (fdcon[s].c_status == CS_KEYS)
458 		xfree(fdcon[s].c_data);
459 	fdcon[s].c_status = CS_UNUSED;
460 	fdcon[s].c_keytype = 0;
461 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
462 	FD_CLR(s, read_wait);
463 	ncon--;
464 }
465 
466 static void
467 contouch(int s)
468 {
469 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
470 	gettimeofday(&fdcon[s].c_tv, NULL);
471 	fdcon[s].c_tv.tv_sec += timeout;
472 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
473 }
474 
475 static int
476 conrecycle(int s)
477 {
478 	con *c = &fdcon[s];
479 	int ret;
480 
481 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
482 	confree(s);
483 	return (ret);
484 }
485 
486 static void
487 congreet(int s)
488 {
489 	int remote_major = 0, remote_minor = 0, n = 0;
490 	char buf[256], *cp;
491 	char remote_version[sizeof buf];
492 	size_t bufsiz;
493 	con *c = &fdcon[s];
494 
495 	bufsiz = sizeof(buf);
496 	cp = buf;
497 	while (bufsiz-- && (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
498 		if (*cp == '\r')
499 			*cp = '\n';
500 		cp++;
501 	}
502 	if (n < 0) {
503 		if (errno != ECONNREFUSED)
504 			error("read (%s): %s", c->c_name, strerror(errno));
505 		conrecycle(s);
506 		return;
507 	}
508 	if (n == 0) {
509 		error("%s: Connection closed by remote host", c->c_name);
510 		conrecycle(s);
511 		return;
512 	}
513 	if (*cp != '\n' && *cp != '\r') {
514 		error("%s: bad greeting", c->c_name);
515 		confree(s);
516 		return;
517 	}
518 	*cp = '\0';
519 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
520 	    &remote_major, &remote_minor, remote_version) == 3)
521 		compat_datafellows(remote_version);
522 	else
523 		datafellows = 0;
524 	if (c->c_keytype != KT_RSA1) {
525 		if (!ssh2_capable(remote_major, remote_minor)) {
526 			debug("%s doesn't support ssh2", c->c_name);
527 			confree(s);
528 			return;
529 		}
530 	} else if (remote_major != 1) {
531 		debug("%s doesn't support ssh1", c->c_name);
532 		confree(s);
533 		return;
534 	}
535 	fprintf(stderr, "# %s %s\n", c->c_name, chop(buf));
536 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
537 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
538 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
539 	if (atomicio(vwrite, s, buf, n) != n) {
540 		error("write (%s): %s", c->c_name, strerror(errno));
541 		confree(s);
542 		return;
543 	}
544 	if (c->c_keytype != KT_RSA1) {
545 		keyprint(c, keygrab_ssh2(c));
546 		confree(s);
547 		return;
548 	}
549 	c->c_status = CS_SIZE;
550 	contouch(s);
551 }
552 
553 static void
554 conread(int s)
555 {
556 	con *c = &fdcon[s];
557 	int n;
558 
559 	if (c->c_status == CS_CON) {
560 		congreet(s);
561 		return;
562 	}
563 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
564 	if (n < 0) {
565 		error("read (%s): %s", c->c_name, strerror(errno));
566 		confree(s);
567 		return;
568 	}
569 	c->c_off += n;
570 
571 	if (c->c_off == c->c_len)
572 		switch (c->c_status) {
573 		case CS_SIZE:
574 			c->c_plen = htonl(c->c_plen);
575 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
576 			c->c_off = 0;
577 			c->c_data = xmalloc(c->c_len);
578 			c->c_status = CS_KEYS;
579 			break;
580 		case CS_KEYS:
581 			keyprint(c, keygrab_ssh1(c));
582 			confree(s);
583 			return;
584 			break;
585 		default:
586 			fatal("conread: invalid status %d", c->c_status);
587 			break;
588 		}
589 
590 	contouch(s);
591 }
592 
593 static void
594 conloop(void)
595 {
596 	struct timeval seltime, now;
597 	fd_set *r, *e;
598 	con *c;
599 	int i;
600 
601 	gettimeofday(&now, NULL);
602 	c = TAILQ_FIRST(&tq);
603 
604 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
605 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
606 		seltime = c->c_tv;
607 		seltime.tv_sec -= now.tv_sec;
608 		seltime.tv_usec -= now.tv_usec;
609 		if (seltime.tv_usec < 0) {
610 			seltime.tv_usec += 1000000;
611 			seltime.tv_sec--;
612 		}
613 	} else
614 		seltime.tv_sec = seltime.tv_usec = 0;
615 
616 	r = xmalloc(read_wait_size);
617 	memcpy(r, read_wait, read_wait_size);
618 	e = xmalloc(read_wait_size);
619 	memcpy(e, read_wait, read_wait_size);
620 
621 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
622 	    (errno == EAGAIN || errno == EINTR))
623 		;
624 
625 	for (i = 0; i < maxfd; i++) {
626 		if (FD_ISSET(i, e)) {
627 			error("%s: exception!", fdcon[i].c_name);
628 			confree(i);
629 		} else if (FD_ISSET(i, r))
630 			conread(i);
631 	}
632 	xfree(r);
633 	xfree(e);
634 
635 	c = TAILQ_FIRST(&tq);
636 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
637 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
638 		int s = c->c_fd;
639 
640 		c = TAILQ_NEXT(c, c_link);
641 		conrecycle(s);
642 	}
643 }
644 
645 static void
646 do_host(char *host)
647 {
648 	char *name = strnnsep(&host, " \t\n");
649 	int j;
650 
651 	if (name == NULL)
652 		return;
653 	for (j = KT_RSA1; j <= KT_RSA; j *= 2) {
654 		if (get_keytypes & j) {
655 			while (ncon >= MAXCON)
656 				conloop();
657 			conalloc(name, *host ? host : name, j);
658 		}
659 	}
660 }
661 
662 void
663 fatal(const char *fmt,...)
664 {
665 	va_list args;
666 
667 	va_start(args, fmt);
668 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
669 	va_end(args);
670 	if (nonfatal_fatal)
671 		longjmp(kexjmp, -1);
672 	else
673 		exit(255);
674 }
675 
676 static void
677 usage(void)
678 {
679 	fprintf(stderr, "usage: %s [-v46] [-p port] [-T timeout] [-t type] [-f file]\n"
680 	    "\t\t   [host | addrlist namelist] [...]\n",
681 	    __progname);
682 	exit(1);
683 }
684 
685 int
686 main(int argc, char **argv)
687 {
688 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
689 	int opt, fopt_count = 0;
690 	char *tname;
691 
692 	extern int optind;
693 	extern char *optarg;
694 
695 	__progname = ssh_get_progname(argv[0]);
696 	init_rng();
697 	seed_rng();
698 	TAILQ_INIT(&tq);
699 
700 	if (argc <= 1)
701 		usage();
702 
703 	while ((opt = getopt(argc, argv, "v46p:T:t:f:")) != -1) {
704 		switch (opt) {
705 		case 'p':
706 			ssh_port = a2port(optarg);
707 			if (ssh_port == 0) {
708 				fprintf(stderr, "Bad port '%s'\n", optarg);
709 				exit(1);
710 			}
711 			break;
712 		case 'T':
713 			timeout = convtime(optarg);
714 			if (timeout == -1 || timeout == 0) {
715 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
716 				usage();
717 			}
718 			break;
719 		case 'v':
720 			if (!debug_flag) {
721 				debug_flag = 1;
722 				log_level = SYSLOG_LEVEL_DEBUG1;
723 			}
724 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
725 				log_level++;
726 			else
727 				fatal("Too high debugging level.");
728 			break;
729 		case 'f':
730 			if (strcmp(optarg, "-") == 0)
731 				optarg = NULL;
732 			argv[fopt_count++] = optarg;
733 			break;
734 		case 't':
735 			get_keytypes = 0;
736 			tname = strtok(optarg, ",");
737 			while (tname) {
738 				int type = key_type_from_name(tname);
739 				switch (type) {
740 				case KEY_RSA1:
741 					get_keytypes |= KT_RSA1;
742 					break;
743 				case KEY_DSA:
744 					get_keytypes |= KT_DSA;
745 					break;
746 				case KEY_RSA:
747 					get_keytypes |= KT_RSA;
748 					break;
749 				case KEY_UNSPEC:
750 					fatal("unknown key type %s", tname);
751 				}
752 				tname = strtok(NULL, ",");
753 			}
754 			break;
755 		case '4':
756 			IPv4or6 = AF_INET;
757 			break;
758 		case '6':
759 			IPv4or6 = AF_INET6;
760 			break;
761 		case '?':
762 		default:
763 			usage();
764 		}
765 	}
766 	if (optind == argc && !fopt_count)
767 		usage();
768 
769 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
770 
771 	maxfd = fdlim_get(1);
772 	if (maxfd < 0)
773 		fatal("%s: fdlim_get: bad value", __progname);
774 	if (maxfd > MAXMAXFD)
775 		maxfd = MAXMAXFD;
776 	if (MAXCON <= 0)
777 		fatal("%s: not enough file descriptors", __progname);
778 	if (maxfd > fdlim_get(0))
779 		fdlim_set(maxfd);
780 	fdcon = xmalloc(maxfd * sizeof(con));
781 	memset(fdcon, 0, maxfd * sizeof(con));
782 
783 	read_wait_size = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
784 	read_wait = xmalloc(read_wait_size);
785 	memset(read_wait, 0, read_wait_size);
786 
787 	if (fopt_count) {
788 		Linebuf *lb;
789 		char *line;
790 		int j;
791 
792 		for (j = 0; j < fopt_count; j++) {
793 			lb = Linebuf_alloc(argv[j], error);
794 			if (!lb)
795 				continue;
796 			while ((line = Linebuf_getline(lb)) != NULL)
797 				do_host(line);
798 			Linebuf_free(lb);
799 		}
800 	}
801 
802 	while (optind < argc)
803 		do_host(argv[optind++]);
804 
805 	while (ncon > 0)
806 		conloop();
807 
808 	return (0);
809 }
810