xref: /freebsd/crypto/openssh/ssh-keyscan.c (revision 4b17dab0ba7675679933f9f3d4aed1cd28dd0393) 
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 1.40 2002/07/06 17:47:58 stevesk 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 #ifdef IPV4_DEFAULT
35 int IPv4or6 = AF_INET;
36 #else
37 int IPv4or6 = AF_UNSPEC;
38 #endif
39 
40 int ssh_port = SSH_DEFAULT_PORT;
41 
42 #define KT_RSA1	1
43 #define KT_DSA	2
44 #define KT_RSA	4
45 
46 int get_keytypes = KT_RSA1;	/* Get only RSA1 keys by default */
47 
48 #define MAXMAXFD 256
49 
50 /* The number of seconds after which to give up on a TCP connection */
51 int timeout = 5;
52 
53 int maxfd;
54 #define MAXCON (maxfd - 10)
55 
56 #ifdef HAVE___PROGNAME
57 extern char *__progname;
58 #else
59 char *__progname;
60 #endif
61 fd_set *read_wait;
62 size_t read_wait_size;
63 int ncon;
64 int nonfatal_fatal = 0;
65 jmp_buf kexjmp;
66 Key *kexjmp_key;
67 
68 /*
69  * Keep a connection structure for each file descriptor.  The state
70  * associated with file descriptor n is held in fdcon[n].
71  */
72 typedef struct Connection {
73 	u_char c_status;	/* State of connection on this file desc. */
74 #define CS_UNUSED 0		/* File descriptor unused */
75 #define CS_CON 1		/* Waiting to connect/read greeting */
76 #define CS_SIZE 2		/* Waiting to read initial packet size */
77 #define CS_KEYS 3		/* Waiting to read public key packet */
78 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
79 	int c_plen;		/* Packet length field for ssh packet */
80 	int c_len;		/* Total bytes which must be read. */
81 	int c_off;		/* Length of data read so far. */
82 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
83 	char *c_namebase;	/* Address to free for c_name and c_namelist */
84 	char *c_name;		/* Hostname of connection for errors */
85 	char *c_namelist;	/* Pointer to other possible addresses */
86 	char *c_output_name;	/* Hostname of connection for output */
87 	char *c_data;		/* Data read from this fd */
88 	Kex *c_kex;		/* The key-exchange struct for ssh2 */
89 	struct timeval c_tv;	/* Time at which connection gets aborted */
90 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
91 } con;
92 
93 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
94 con *fdcon;
95 
96 /*
97  *  This is just a wrapper around fgets() to make it usable.
98  */
99 
100 /* Stress-test.  Increase this later. */
101 #define LINEBUF_SIZE 16
102 
103 typedef struct {
104 	char *buf;
105 	u_int size;
106 	int lineno;
107 	const char *filename;
108 	FILE *stream;
109 	void (*errfun) (const char *,...);
110 } Linebuf;
111 
112 static Linebuf *
113 Linebuf_alloc(const char *filename, void (*errfun) (const char *,...))
114 {
115 	Linebuf *lb;
116 
117 	if (!(lb = malloc(sizeof(*lb)))) {
118 		if (errfun)
119 			(*errfun) ("linebuf (%s): malloc failed\n",
120 			    filename ? filename : "(stdin)");
121 		return (NULL);
122 	}
123 	if (filename) {
124 		lb->filename = filename;
125 		if (!(lb->stream = fopen(filename, "r"))) {
126 			xfree(lb);
127 			if (errfun)
128 				(*errfun) ("%s: %s\n", filename, strerror(errno));
129 			return (NULL);
130 		}
131 	} else {
132 		lb->filename = "(stdin)";
133 		lb->stream = stdin;
134 	}
135 
136 	if (!(lb->buf = malloc(lb->size = LINEBUF_SIZE))) {
137 		if (errfun)
138 			(*errfun) ("linebuf (%s): malloc failed\n", lb->filename);
139 		xfree(lb);
140 		return (NULL);
141 	}
142 	lb->errfun = errfun;
143 	lb->lineno = 0;
144 	return (lb);
145 }
146 
147 static void
148 Linebuf_free(Linebuf * lb)
149 {
150 	fclose(lb->stream);
151 	xfree(lb->buf);
152 	xfree(lb);
153 }
154 
155 #if 0
156 static void
157 Linebuf_restart(Linebuf * lb)
158 {
159 	clearerr(lb->stream);
160 	rewind(lb->stream);
161 	lb->lineno = 0;
162 }
163 
164 static int
165 Linebuf_lineno(Linebuf * lb)
166 {
167 	return (lb->lineno);
168 }
169 #endif
170 
171 static char *
172 Linebuf_getline(Linebuf * lb)
173 {
174 	int n = 0;
175 	void *p;
176 
177 	lb->lineno++;
178 	for (;;) {
179 		/* Read a line */
180 		if (!fgets(&lb->buf[n], lb->size - n, lb->stream)) {
181 			if (ferror(lb->stream) && lb->errfun)
182 				(*lb->errfun)("%s: %s\n", lb->filename,
183 				    strerror(errno));
184 			return (NULL);
185 		}
186 		n = strlen(lb->buf);
187 
188 		/* Return it or an error if it fits */
189 		if (n > 0 && lb->buf[n - 1] == '\n') {
190 			lb->buf[n - 1] = '\0';
191 			return (lb->buf);
192 		}
193 		if (n != lb->size - 1) {
194 			if (lb->errfun)
195 				(*lb->errfun)("%s: skipping incomplete last line\n",
196 				    lb->filename);
197 			return (NULL);
198 		}
199 		/* Double the buffer if we need more space */
200 		lb->size *= 2;
201 		if ((p = realloc(lb->buf, lb->size)) == NULL) {
202 			lb->size /= 2;
203 			if (lb->errfun)
204 				(*lb->errfun)("linebuf (%s): realloc failed\n",
205 				    lb->filename);
206 			return (NULL);
207 		}
208 		lb->buf = p;
209 	}
210 }
211 
212 static int
213 fdlim_get(int hard)
214 {
215 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
216 	struct rlimit rlfd;
217 
218 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
219 		return (-1);
220 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
221 		return 10000;
222 	else
223 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
224 #elif defined (HAVE_SYSCONF)
225 	return sysconf (_SC_OPEN_MAX);
226 #else
227 	return 10000;
228 #endif
229 }
230 
231 static int
232 fdlim_set(int lim)
233 {
234 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
235 	struct rlimit rlfd;
236 #endif
237 
238 	if (lim <= 0)
239 		return (-1);
240 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
241 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
242 		return (-1);
243 	rlfd.rlim_cur = lim;
244 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
245 		return (-1);
246 #elif defined (HAVE_SETDTABLESIZE)
247 	setdtablesize(lim);
248 #endif
249 	return (0);
250 }
251 
252 /*
253  * This is an strsep function that returns a null field for adjacent
254  * separators.  This is the same as the 4.4BSD strsep, but different from the
255  * one in the GNU libc.
256  */
257 static char *
258 xstrsep(char **str, const char *delim)
259 {
260 	char *s, *e;
261 
262 	if (!**str)
263 		return (NULL);
264 
265 	s = *str;
266 	e = s + strcspn(s, delim);
267 
268 	if (*e != '\0')
269 		*e++ = '\0';
270 	*str = e;
271 
272 	return (s);
273 }
274 
275 /*
276  * Get the next non-null token (like GNU strsep).  Strsep() will return a
277  * null token for two adjacent separators, so we may have to loop.
278  */
279 static char *
280 strnnsep(char **stringp, char *delim)
281 {
282 	char *tok;
283 
284 	do {
285 		tok = xstrsep(stringp, delim);
286 	} while (tok && *tok == '\0');
287 	return (tok);
288 }
289 
290 static Key *
291 keygrab_ssh1(con *c)
292 {
293 	static Key *rsa;
294 	static Buffer msg;
295 
296 	if (rsa == NULL) {
297 		buffer_init(&msg);
298 		rsa = key_new(KEY_RSA1);
299 	}
300 	buffer_append(&msg, c->c_data, c->c_plen);
301 	buffer_consume(&msg, 8 - (c->c_plen & 7));	/* padding */
302 	if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
303 		error("%s: invalid packet type", c->c_name);
304 		buffer_clear(&msg);
305 		return NULL;
306 	}
307 	buffer_consume(&msg, 8);		/* cookie */
308 
309 	/* server key */
310 	(void) buffer_get_int(&msg);
311 	buffer_get_bignum(&msg, rsa->rsa->e);
312 	buffer_get_bignum(&msg, rsa->rsa->n);
313 
314 	/* host key */
315 	(void) buffer_get_int(&msg);
316 	buffer_get_bignum(&msg, rsa->rsa->e);
317 	buffer_get_bignum(&msg, rsa->rsa->n);
318 
319 	buffer_clear(&msg);
320 
321 	return (rsa);
322 }
323 
324 static int
325 hostjump(Key *hostkey)
326 {
327 	kexjmp_key = hostkey;
328 	longjmp(kexjmp, 1);
329 }
330 
331 static int
332 ssh2_capable(int remote_major, int remote_minor)
333 {
334 	switch (remote_major) {
335 	case 1:
336 		if (remote_minor == 99)
337 			return 1;
338 		break;
339 	case 2:
340 		return 1;
341 	default:
342 		break;
343 	}
344 	return 0;
345 }
346 
347 static Key *
348 keygrab_ssh2(con *c)
349 {
350 	int j;
351 
352 	packet_set_connection(c->c_fd, c->c_fd);
353 	enable_compat20();
354 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = c->c_keytype == KT_DSA?
355 	    "ssh-dss": "ssh-rsa";
356 	c->c_kex = kex_setup(myproposal);
357 	c->c_kex->verify_host_key = hostjump;
358 
359 	if (!(j = setjmp(kexjmp))) {
360 		nonfatal_fatal = 1;
361 		dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex);
362 		fprintf(stderr, "Impossible! dispatch_run() returned!\n");
363 		exit(1);
364 	}
365 	nonfatal_fatal = 0;
366 	xfree(c->c_kex);
367 	c->c_kex = NULL;
368 	packet_close();
369 
370 	return j < 0? NULL : kexjmp_key;
371 }
372 
373 static void
374 keyprint(con *c, Key *key)
375 {
376 	if (!key)
377 		return;
378 
379 	fprintf(stdout, "%s ", c->c_output_name ? c->c_output_name : c->c_name);
380 	key_write(key, stdout);
381 	fputs("\n", stdout);
382 }
383 
384 static int
385 tcpconnect(char *host)
386 {
387 	struct addrinfo hints, *ai, *aitop;
388 	char strport[NI_MAXSERV];
389 	int gaierr, s = -1;
390 
391 	snprintf(strport, sizeof strport, "%d", ssh_port);
392 	memset(&hints, 0, sizeof(hints));
393 	hints.ai_family = IPv4or6;
394 	hints.ai_socktype = SOCK_STREAM;
395 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
396 		fatal("getaddrinfo %s: %s", host, gai_strerror(gaierr));
397 	for (ai = aitop; ai; ai = ai->ai_next) {
398 		s = socket(ai->ai_family, SOCK_STREAM, 0);
399 		if (s < 0) {
400 			error("socket: %s", strerror(errno));
401 			continue;
402 		}
403 		if (fcntl(s, F_SETFL, O_NONBLOCK) < 0)
404 			fatal("F_SETFL: %s", strerror(errno));
405 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
406 		    errno != EINPROGRESS)
407 			error("connect (`%s'): %s", host, strerror(errno));
408 		else
409 			break;
410 		close(s);
411 		s = -1;
412 	}
413 	freeaddrinfo(aitop);
414 	return s;
415 }
416 
417 static int
418 conalloc(char *iname, char *oname, int keytype)
419 {
420 	char *namebase, *name, *namelist;
421 	int s;
422 
423 	namebase = namelist = xstrdup(iname);
424 
425 	do {
426 		name = xstrsep(&namelist, ",");
427 		if (!name) {
428 			xfree(namebase);
429 			return (-1);
430 		}
431 	} while ((s = tcpconnect(name)) < 0);
432 
433 	if (s >= maxfd)
434 		fatal("conalloc: fdno %d too high", s);
435 	if (fdcon[s].c_status)
436 		fatal("conalloc: attempt to reuse fdno %d", s);
437 
438 	fdcon[s].c_fd = s;
439 	fdcon[s].c_status = CS_CON;
440 	fdcon[s].c_namebase = namebase;
441 	fdcon[s].c_name = name;
442 	fdcon[s].c_namelist = namelist;
443 	fdcon[s].c_output_name = xstrdup(oname);
444 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
445 	fdcon[s].c_len = 4;
446 	fdcon[s].c_off = 0;
447 	fdcon[s].c_keytype = keytype;
448 	gettimeofday(&fdcon[s].c_tv, NULL);
449 	fdcon[s].c_tv.tv_sec += timeout;
450 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
451 	FD_SET(s, read_wait);
452 	ncon++;
453 	return (s);
454 }
455 
456 static void
457 confree(int s)
458 {
459 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
460 		fatal("confree: attempt to free bad fdno %d", s);
461 	close(s);
462 	xfree(fdcon[s].c_namebase);
463 	xfree(fdcon[s].c_output_name);
464 	if (fdcon[s].c_status == CS_KEYS)
465 		xfree(fdcon[s].c_data);
466 	fdcon[s].c_status = CS_UNUSED;
467 	fdcon[s].c_keytype = 0;
468 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
469 	FD_CLR(s, read_wait);
470 	ncon--;
471 }
472 
473 static void
474 contouch(int s)
475 {
476 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
477 	gettimeofday(&fdcon[s].c_tv, NULL);
478 	fdcon[s].c_tv.tv_sec += timeout;
479 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
480 }
481 
482 static int
483 conrecycle(int s)
484 {
485 	con *c = &fdcon[s];
486 	int ret;
487 
488 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
489 	confree(s);
490 	return (ret);
491 }
492 
493 static void
494 congreet(int s)
495 {
496 	int remote_major, remote_minor, n = 0;
497 	char buf[256], *cp;
498 	char remote_version[sizeof buf];
499 	size_t bufsiz;
500 	con *c = &fdcon[s];
501 
502 	bufsiz = sizeof(buf);
503 	cp = buf;
504 	while (bufsiz-- && (n = read(s, cp, 1)) == 1 && *cp != '\n') {
505 		if (*cp == '\r')
506 			*cp = '\n';
507 		cp++;
508 	}
509 	if (n < 0) {
510 		if (errno != ECONNREFUSED)
511 			error("read (%s): %s", c->c_name, strerror(errno));
512 		conrecycle(s);
513 		return;
514 	}
515 	if (n == 0) {
516 		error("%s: Connection closed by remote host", c->c_name);
517 		conrecycle(s);
518 		return;
519 	}
520 	if (*cp != '\n' && *cp != '\r') {
521 		error("%s: bad greeting", c->c_name);
522 		confree(s);
523 		return;
524 	}
525 	*cp = '\0';
526 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
527 	    &remote_major, &remote_minor, remote_version) == 3)
528 		compat_datafellows(remote_version);
529 	else
530 		datafellows = 0;
531 	if (c->c_keytype != KT_RSA1) {
532 		if (!ssh2_capable(remote_major, remote_minor)) {
533 			debug("%s doesn't support ssh2", c->c_name);
534 			confree(s);
535 			return;
536 		}
537 	} else if (remote_major != 1) {
538 		debug("%s doesn't support ssh1", c->c_name);
539 		confree(s);
540 		return;
541 	}
542 	fprintf(stderr, "# %s %s\n", c->c_name, chop(buf));
543 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
544 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
545 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
546 	if (atomicio(write, s, buf, n) != n) {
547 		error("write (%s): %s", c->c_name, strerror(errno));
548 		confree(s);
549 		return;
550 	}
551 	if (c->c_keytype != KT_RSA1) {
552 		keyprint(c, keygrab_ssh2(c));
553 		confree(s);
554 		return;
555 	}
556 	c->c_status = CS_SIZE;
557 	contouch(s);
558 }
559 
560 static void
561 conread(int s)
562 {
563 	con *c = &fdcon[s];
564 	int n;
565 
566 	if (c->c_status == CS_CON) {
567 		congreet(s);
568 		return;
569 	}
570 	n = read(s, c->c_data + c->c_off, c->c_len - c->c_off);
571 	if (n < 0) {
572 		error("read (%s): %s", c->c_name, strerror(errno));
573 		confree(s);
574 		return;
575 	}
576 	c->c_off += n;
577 
578 	if (c->c_off == c->c_len)
579 		switch (c->c_status) {
580 		case CS_SIZE:
581 			c->c_plen = htonl(c->c_plen);
582 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
583 			c->c_off = 0;
584 			c->c_data = xmalloc(c->c_len);
585 			c->c_status = CS_KEYS;
586 			break;
587 		case CS_KEYS:
588 			keyprint(c, keygrab_ssh1(c));
589 			confree(s);
590 			return;
591 			break;
592 		default:
593 			fatal("conread: invalid status %d", c->c_status);
594 			break;
595 		}
596 
597 	contouch(s);
598 }
599 
600 static void
601 conloop(void)
602 {
603 	struct timeval seltime, now;
604 	fd_set *r, *e;
605 	con *c;
606 	int i;
607 
608 	gettimeofday(&now, NULL);
609 	c = TAILQ_FIRST(&tq);
610 
611 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
612 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
613 		seltime = c->c_tv;
614 		seltime.tv_sec -= now.tv_sec;
615 		seltime.tv_usec -= now.tv_usec;
616 		if (seltime.tv_usec < 0) {
617 			seltime.tv_usec += 1000000;
618 			seltime.tv_sec--;
619 		}
620 	} else
621 		seltime.tv_sec = seltime.tv_usec = 0;
622 
623 	r = xmalloc(read_wait_size);
624 	memcpy(r, read_wait, read_wait_size);
625 	e = xmalloc(read_wait_size);
626 	memcpy(e, read_wait, read_wait_size);
627 
628 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
629 	    (errno == EAGAIN || errno == EINTR))
630 		;
631 
632 	for (i = 0; i < maxfd; i++) {
633 		if (FD_ISSET(i, e)) {
634 			error("%s: exception!", fdcon[i].c_name);
635 			confree(i);
636 		} else if (FD_ISSET(i, r))
637 			conread(i);
638 	}
639 	xfree(r);
640 	xfree(e);
641 
642 	c = TAILQ_FIRST(&tq);
643 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
644 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
645 		int s = c->c_fd;
646 
647 		c = TAILQ_NEXT(c, c_link);
648 		conrecycle(s);
649 	}
650 }
651 
652 static void
653 do_host(char *host)
654 {
655 	char *name = strnnsep(&host, " \t\n");
656 	int j;
657 
658 	if (name == NULL)
659 		return;
660 	for (j = KT_RSA1; j <= KT_RSA; j *= 2) {
661 		if (get_keytypes & j) {
662 			while (ncon >= MAXCON)
663 				conloop();
664 			conalloc(name, *host ? host : name, j);
665 		}
666 	}
667 }
668 
669 void
670 fatal(const char *fmt,...)
671 {
672 	va_list args;
673 
674 	va_start(args, fmt);
675 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
676 	va_end(args);
677 	if (nonfatal_fatal)
678 		longjmp(kexjmp, -1);
679 	else
680 		fatal_cleanup();
681 }
682 
683 static void
684 usage(void)
685 {
686 	fprintf(stderr, "usage: %s [-v46] [-p port] [-T timeout] [-f file]\n"
687 	    "\t\t   [host | addrlist namelist] [...]\n",
688 	    __progname);
689 	exit(1);
690 }
691 
692 int
693 main(int argc, char **argv)
694 {
695 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
696 	int opt, fopt_count = 0;
697 	char *tname;
698 
699 	extern int optind;
700 	extern char *optarg;
701 
702 	__progname = get_progname(argv[0]);
703 	init_rng();
704 	seed_rng();
705 	TAILQ_INIT(&tq);
706 
707 	if (argc <= 1)
708 		usage();
709 
710 	while ((opt = getopt(argc, argv, "v46p:T:t:f:")) != -1) {
711 		switch (opt) {
712 		case 'p':
713 			ssh_port = a2port(optarg);
714 			if (ssh_port == 0) {
715 				fprintf(stderr, "Bad port '%s'\n", optarg);
716 				exit(1);
717 			}
718 			break;
719 		case 'T':
720 			timeout = convtime(optarg);
721 			if (timeout == -1 || timeout == 0) {
722 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
723 				usage();
724 			}
725 			break;
726 		case 'v':
727 			if (!debug_flag) {
728 				debug_flag = 1;
729 				log_level = SYSLOG_LEVEL_DEBUG1;
730 			}
731 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
732 				log_level++;
733 			else
734 				fatal("Too high debugging level.");
735 			break;
736 		case 'f':
737 			if (strcmp(optarg, "-") == 0)
738 				optarg = NULL;
739 			argv[fopt_count++] = optarg;
740 			break;
741 		case 't':
742 			get_keytypes = 0;
743 			tname = strtok(optarg, ",");
744 			while (tname) {
745 				int type = key_type_from_name(tname);
746 				switch (type) {
747 				case KEY_RSA1:
748 					get_keytypes |= KT_RSA1;
749 					break;
750 				case KEY_DSA:
751 					get_keytypes |= KT_DSA;
752 					break;
753 				case KEY_RSA:
754 					get_keytypes |= KT_RSA;
755 					break;
756 				case KEY_UNSPEC:
757 					fatal("unknown key type %s", tname);
758 				}
759 				tname = strtok(NULL, ",");
760 			}
761 			break;
762 		case '4':
763 			IPv4or6 = AF_INET;
764 			break;
765 		case '6':
766 			IPv4or6 = AF_INET6;
767 			break;
768 		case '?':
769 		default:
770 			usage();
771 		}
772 	}
773 	if (optind == argc && !fopt_count)
774 		usage();
775 
776 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
777 
778 	maxfd = fdlim_get(1);
779 	if (maxfd < 0)
780 		fatal("%s: fdlim_get: bad value", __progname);
781 	if (maxfd > MAXMAXFD)
782 		maxfd = MAXMAXFD;
783 	if (MAXCON <= 0)
784 		fatal("%s: not enough file descriptors", __progname);
785 	if (maxfd > fdlim_get(0))
786 		fdlim_set(maxfd);
787 	fdcon = xmalloc(maxfd * sizeof(con));
788 	memset(fdcon, 0, maxfd * sizeof(con));
789 
790 	read_wait_size = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
791 	read_wait = xmalloc(read_wait_size);
792 	memset(read_wait, 0, read_wait_size);
793 
794 	if (fopt_count) {
795 		Linebuf *lb;
796 		char *line;
797 		int j;
798 
799 		for (j = 0; j < fopt_count; j++) {
800 			lb = Linebuf_alloc(argv[j], error);
801 			if (!lb)
802 				continue;
803 			while ((line = Linebuf_getline(lb)) != NULL)
804 				do_host(line);
805 			Linebuf_free(lb);
806 		}
807 	}
808 
809 	while (optind < argc)
810 		do_host(argv[optind++]);
811 
812 	while (ncon > 0)
813 		conloop();
814 
815 	return (0);
816 }
817