20001205

- (bal) OpenSSH CVS updates:
   - markus@cvs.openbsd.org 2000/12/04 19:24:02
     [ssh-keyscan.c ssh-keyscan.1]
     David Maziere's ssh-keyscan, ok niels@
 - (bal) Updated Makefile.in to include ssh-keyscan that was just added
   to the recent OpenBSD source tree.

ChangeLog

@@ -1,6 +1,14 @@
+20001205
+ - (bal) OpenSSH CVS updates:
+   - markus@cvs.openbsd.org 2000/12/04 19:24:02
+     [ssh-keyscan.c ssh-keyscan.1]
+     David Maziere's ssh-keyscan, ok niels@
+ - (bal) Updated Makefile.in to include ssh-keyscan that was just added
+   to the recent OpenBSD source tree.
+
 20001204
  - (bal) More C functions defined in NeXT that are unaccessable without
-   defining -POSIX.  
+   defining -POSIX. 
  - (bal) OpenBSD CVS updates: 
    - markus@cvs.openbsd.org 2000/12/03 11:29:04 
      [compat.c]

Makefile.in

@@ -34,7 +34,7 @@ SSH_MODE= @SSHMODE@
 
 INSTALL_SSH_PRNG_CMDS=@INSTALL_SSH_PRNG_CMDS@
 
-TARGETS=ssh$(EXEEXT) sshd$(EXEEXT) ssh-add$(EXEEXT) ssh-keygen$(EXEEXT) ssh-agent$(EXEEXT) scp$(EXEEXT) sftp-server$(EXEEXT)
+TARGETS=ssh$(EXEEXT) sshd$(EXEEXT) ssh-add$(EXEEXT) ssh-keygen$(EXEEXT) ssh-keyscan${EXEEXT} ssh-agent$(EXEEXT) scp$(EXEEXT) sftp-server$(EXEEXT)
 
 LIBSSH_OBJS=atomicio.o authfd.o authfile.o bufaux.o buffer.o canohost.o channels.o cipher.o cli.o compat.o compress.o crc32.o cygwin_util.o deattack.o dispatch.o hmac.o hostfile.o key.o kex.o log.o match.o mpaux.o nchan.o packet.o radix.o rijndael.o entropy.o readpass.o rsa.o ssh-dss.o ssh-rsa.o tildexpand.o ttymodes.o uidswap.o util.o uuencode.o xmalloc.o 
 
@@ -44,8 +44,8 @@ SSHOBJS= ssh.o sshconnect.o sshconnect1.o sshconnect2.o log-client.o readconf.o
 
 SSHDOBJS= sshd.o auth.o auth1.o auth2.o auth-skey.o auth2-skey.o auth-rhosts.o auth-options.o auth-krb4.o auth-pam.o auth2-pam.o auth-passwd.o auth-rsa.o auth-rh-rsa.o dh.o pty.o log-server.o login.o loginrec.o servconf.o serverloop.o md5crypt.o session.o
 
-TROFFMAN	= scp.1 ssh-add.1 ssh-agent.1 ssh-keygen.1 ssh.1 sshd.8 sftp-server.8
-CATMAN		= scp.0 ssh-add.0 ssh-agent.0 ssh-keygen.0 ssh.0 sshd.0 sftp-server.0
+TROFFMAN	= scp.1 ssh-add.1 ssh-agent.1 ssh-keygen.1 ssh-keyscan.1 ssh.1 sshd.8 sftp-server.8
+CATMAN		= scp.0 ssh-add.0 ssh-agent.0 ssh-keygen.0 ssh-keyscan.0 ssh.0 sshd.0 sftp-server.0
 MANPAGES	= @MANTYPE@
 
 CONFIGFILES=sshd_config ssh_config primes
@@ -100,6 +100,9 @@ ssh-agent$(EXEEXT): libopenbsd-compat.a libssh.a ssh-agent.o log-client.o
 ssh-keygen$(EXEEXT): libopenbsd-compat.a libssh.a ssh-keygen.o log-client.o
 	$(LD) -o $@ ssh-keygen.o log-client.o $(LDFLAGS) -lssh -lopenbsd-compat $(LIBS) 
 
+ssh-keyscan$(EXEEXT): libopenbsd-compat.a libssh.a log-client.o ssh-keyscan.o
+	$(LD) -o $@ ssh-keyscan.o log-client.o $(LDFLAGS) -lssh -lopenbsd-compat $(LIBS) 
+
 sftp-server$(EXEEXT): libopenbsd-compat.a libssh.a sftp-server.o log-server.o
 	$(LD) -o $@ sftp-server.o log-server.o $(LDFLAGS) -lssh -lopenbsd-compat $(LIBS) 
 
@@ -146,6 +149,7 @@ install-files:
 	$(INSTALL) -m 0755 -s ssh-add $(DESTDIR)$(bindir)/ssh-add
 	$(INSTALL) -m 0755 -s ssh-agent $(DESTDIR)$(bindir)/ssh-agent
 	$(INSTALL) -m 0755 -s ssh-keygen $(DESTDIR)$(bindir)/ssh-keygen
+	$(INSTALL) -m 0775 -s ssh-keyscan $(DESTDIR)$(bindir)/ssh-keyscan
 	$(INSTALL) -m 0755 -s sshd $(DESTDIR)$(sbindir)/sshd
 	$(INSTALL) -m 0755 -s sftp-server $(DESTDIR)$(libexecdir)/sftp-server
 	$(INSTALL) -m 644 ssh.[01].out $(DESTDIR)$(mandir)/$(mansubdir)1/ssh.1
@@ -229,12 +233,14 @@ uninstall:
 	-rm -f $(DESTDIR)$(bindir)/ssh-add$(EXEEXT)
 	-rm -f $(DESTDIR)$(bindir)/ssh-agent$(EXEEXT)
 	-rm -f $(DESTDIR)$(bindir)/ssh-keygen$(EXEEXT)
+	-rm -f $(DESTDIR)$(bindir)/ssh-keyscan$(EXEEXT)
 	-rm -f $(DESTDIR)$(sbindir)/sshd$(EXEEXT)
 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/ssh.1
 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/scp.1
 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/ssh-add.1
 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/ssh-agent.1
 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/ssh-keygen.1
+	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/ssh-keyscan.1
 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)8/sshd.8
 	-rm -f $(DESTDIR)$(bindir)/slogin
 	-rm -f $(DESTDIR)$(mandir)/$(mansubdir)1/slogin.1

ssh-keyscan.1

@@ -0,0 +1,94 @@
+.Dd January 1, 1996
+.Dt ssh-keyscan 1
+.Os
+.Sh NAME
+.Nm ssh-keyscan
+.Nd gather ssh public keys
+.Sh SYNOPSIS
+.Nm ssh-keyscan
+.Op Fl t Ar timeout
+.Op Ar -- | host | addrlist namelist
+.Op Fl f Ar files ...
+.Sh DESCRIPTION
+.Nm
+is a utility for gathering the public ssh host keys of a number of
+hosts.  It was designed to aid in building and verifying
+.Pa ssh_known_hosts
+files.
+.Nm
+provides a minimal interface suitable for use by shell and perl
+scripts.
+.Pp
+.Nm
+uses non-blocking socket I/O to contact as many hosts as possible in
+parallel, so it is very efficient.  The keys from a domain of 1,000
+hosts can be collected in tens of seconds, even when some of those
+hosts are down or do not run ssh.  You do not need login access to the
+machines you are scanning, nor does does the scanning process involve
+any encryption.
+.Sh SECURITY
+If you make an ssh_known_hosts file using
+.Nm
+without verifying the keys, you will be vulnerable to
+.I man in the middle
+attacks.
+On the other hand, if your security model allows such a risk,
+.Nm
+can help you detect tampered keyfiles or man in the middle attacks which
+have begun after you created your ssh_known_hosts file.
+.Sh OPTIONS
+.Bl -tag -width Ds
+.It Fl t
+Set the timeout for connection attempts.  If 
+.Pa timeout
+seconds have elapsed since a connection was initiated to a host or since the
+last time anything was read from that host, then the connection is
+closed and the host in question considered unavailable.  Default is 5
+seconds.
+.It Fl f
+Read hosts or 
+.Pa addrlist namelist
+pairs from this file, one per line.
+If
+.Pa -
+is supplied instead of a filename,
+.Nm
+will read hosts or 
+.Pa addrlist namelist
+pairs from the standard input.
+.Sh EXAMPLES
+.Pp
+Print the host key for machine
+.Pa hostname :
+.Bd -literal
+ssh-keyscan hostname
+.Ed
+.Pp
+Find all hosts from the file
+.Pa ssh_hosts
+which have new or different keys from those in the sorted file
+.Pa ssh_known_hosts :
+.Bd -literal
+ssh-keyscan -f ssh_hosts | sort -u - ssh_known_hosts | \e\ 
+	diff ssh_known_hosts -
+.Ed
+.Pp
+.Sh FILES
+.Pp
+.Pa Input format:
+1.2.3.4,1.2.4.4 name.my.domain,name,n.my.domain,n,1.2.3.4,1.2.4.4
+.Pp
+.Pa Output format:
+host-or-namelist bits exponent modulus
+.Pp
+.Pa /etc/ssh_known_hosts
+.Sh BUGS
+It generates "Connection closed by remote host" messages on the consoles
+of all the machines it scans.
+This is because it opens a connection to the ssh port, reads the public
+key, and drops the connection as soon as it gets the key.
+.Sh SEE ALSO
+.Xr ssh 1
+.Xr sshd 8
+.Sh AUTHOR
+David Mazieres <dm@lcs.mit.edu>

ssh-keyscan.c

@@ -0,0 +1,605 @@
+/*
+ * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
+ *
+ * Modification and redistribution in source and binary forms is
+ * permitted provided that due credit is given to the author and the
+ * OpenBSD project (for instance by leaving this copyright notice
+ * intact).
+ */
+
+#include "includes.h"
+RCSID("$OpenBSD: ssh-keyscan.c,v 1.1 2000/12/04 19:24:02 markus Exp $");
+
+#include <sys/queue.h>
+#include <err.h>
+#include <errno.h>
+
+#include <openssl/bn.h>
+#include <openssl/rsa.h>
+#include <openssl/dsa.h>
+
+#include "xmalloc.h"
+#include "ssh.h"
+#include "key.h"
+#include "buffer.h"
+#include "bufaux.h"
+
+static int argno = 1;		/* Number of argument currently being parsed */
+
+int family = AF_UNSPEC;		/* IPv4, IPv6 or both */
+
+#define PORT 22
+#define MAXMAXFD 256
+
+/* The number of seconds after which to give up on a TCP connection */
+int timeout = 5;
+
+int maxfd;
+#define maxcon (maxfd - 10)
+
+char *prog;
+fd_set read_wait;
+int ncon;
+
+/*
+ * Keep a connection structure for each file descriptor.  The state
+ * associated with file descriptor n is held in fdcon[n].
+ */
+typedef struct Connection {
+	unsigned char c_status;	/* State of connection on this file desc. */
+#define CS_UNUSED 0		/* File descriptor unused */
+#define CS_CON 1		/* Waiting to connect/read greeting */
+#define CS_SIZE 2		/* Waiting to read initial packet size */
+#define CS_KEYS 3		/* Waiting to read public key packet */
+	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
+	int c_plen;		/* Packet length field for ssh packet */
+	int c_len;		/* Total bytes which must be read. */
+	int c_off;		/* Length of data read so far. */
+	char *c_namebase;	/* Address to free for c_name and c_namelist */
+	char *c_name;		/* Hostname of connection for errors */
+	char *c_namelist;	/* Pointer to other possible addresses */
+	char *c_output_name;	/* Hostname of connection for output */
+	char *c_data;		/* Data read from this fd */
+	struct timeval c_tv;	/* Time at which connection gets aborted */
+	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
+} con;
+
+TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
+con *fdcon;
+
+/*
+ *  This is just a wrapper around fgets() to make it usable.
+ */
+
+/* Stress-test.  Increase this later. */
+#define LINEBUF_SIZE 16
+
+typedef struct {
+	char *buf;
+	unsigned int size;
+	int lineno;
+	const char *filename;
+	FILE *stream;
+	void (*errfun) (const char *,...);
+} Linebuf;
+
+static inline Linebuf *
+Linebuf_alloc(const char *filename, void (*errfun) (const char *,...))
+{
+	Linebuf *lb;
+
+	if (!(lb = malloc(sizeof(*lb)))) {
+		if (errfun)
+			(*errfun) ("linebuf (%s): malloc failed\n", lb->filename);
+		return (NULL);
+	}
+	if (filename) {
+		lb->filename = filename;
+		if (!(lb->stream = fopen(filename, "r"))) {
+			free(lb);
+			if (errfun)
+				(*errfun) ("%s: %s\n", filename, strerror(errno));
+			return (NULL);
+		}
+	} else {
+		lb->filename = "(stdin)";
+		lb->stream = stdin;
+	}
+
+	if (!(lb->buf = malloc(lb->size = LINEBUF_SIZE))) {
+		if (errfun)
+			(*errfun) ("linebuf (%s): malloc failed\n", lb->filename);
+		free(lb);
+		return (NULL);
+	}
+	lb->errfun = errfun;
+	lb->lineno = 0;
+	return (lb);
+}
+
+static inline void
+Linebuf_free(Linebuf * lb)
+{
+	fclose(lb->stream);
+	free(lb->buf);
+	free(lb);
+}
+
+static inline void
+Linebuf_restart(Linebuf * lb)
+{
+	clearerr(lb->stream);
+	rewind(lb->stream);
+	lb->lineno = 0;
+}
+
+static inline int
+Linebuf_lineno(Linebuf * lb)
+{
+	return (lb->lineno);
+}
+
+static inline char *
+getline(Linebuf * lb)
+{
+	int n = 0;
+
+	lb->lineno++;
+	for (;;) {
+		/* Read a line */
+		if (!fgets(&lb->buf[n], lb->size - n, lb->stream)) {
+			if (ferror(lb->stream) && lb->errfun)
+				(*lb->errfun) ("%s: %s\n", lb->filename, strerror(errno));
+			return (NULL);
+		}
+		n = strlen(lb->buf);
+
+		/* Return it or an error if it fits */
+		if (n > 0 && lb->buf[n - 1] == '\n') {
+			lb->buf[n - 1] = '\0';
+			return (lb->buf);
+		}
+		if (n != lb->size - 1) {
+			if (lb->errfun)
+				(*lb->errfun) ("%s: skipping incomplete last line\n", lb->filename);
+			return (NULL);
+		}
+		/* Double the buffer if we need more space */
+		if (!(lb->buf = realloc(lb->buf, (lb->size *= 2)))) {
+			if (lb->errfun)
+				(*lb->errfun) ("linebuf (%s): realloc failed\n", lb->filename);
+			return (NULL);
+		}
+	}
+}
+
+static int
+fdlim_get(int hard)
+{
+	struct rlimit rlfd;
+	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
+		return (-1);
+	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
+		return 10000;
+	else
+		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
+}
+
+static int
+fdlim_set(int lim)
+{
+	struct rlimit rlfd;
+	if (lim <= 0)
+		return (-1);
+	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
+		return (-1);
+	rlfd.rlim_cur = lim;
+	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
+		return (-1);
+	return (0);
+}
+
+/*
+ * This is an strsep function that returns a null field for adjacent
+ * separators.  This is the same as the 4.4BSD strsep, but different from the
+ * one in the GNU libc.
+ */
+inline char *
+xstrsep(char **str, const char *delim)
+{
+	char *s, *e;
+
+	if (!**str)
+		return (NULL);
+
+	s = *str;
+	e = s + strcspn(s, delim);
+
+	if (*e != '\0')
+		*e++ = '\0';
+	*str = e;
+
+	return (s);
+}
+
+/*
+ * Get the next non-null token (like GNU strsep).  Strsep() will return a
+ * null token for two adjacent separators, so we may have to loop.
+ */
+char *
+strnnsep(char **stringp, char *delim)
+{
+	char *tok;
+
+	do {
+		tok = xstrsep(stringp, delim);
+	} while (tok && *tok == '\0');
+	return (tok);
+}
+
+void
+keyprint(char *host, char *output_name, char *kd, int len)
+{
+	static Key *rsa;
+	static Buffer msg;
+
+	if (rsa == NULL) {
+		buffer_init(&msg);
+		rsa = key_new(KEY_RSA1);
+	}
+	buffer_append(&msg, kd, len);
+	buffer_consume(&msg, 8 - (len & 7));	/* padding */
+	if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
+		error("%s: invalid packet type", host);
+		buffer_clear(&msg);
+		return;
+	}
+	buffer_consume(&msg, 8);		/* cookie */
+
+	/* server key */
+	(void) buffer_get_int(&msg);
+	buffer_get_bignum(&msg, rsa->rsa->e);
+	buffer_get_bignum(&msg, rsa->rsa->n);
+
+	/* host key */
+	(void) buffer_get_int(&msg);
+	buffer_get_bignum(&msg, rsa->rsa->e);
+	buffer_get_bignum(&msg, rsa->rsa->n);
+	buffer_clear(&msg);
+
+	fprintf(stdout, "%s ", output_name ? output_name : host);
+	key_write(rsa, stdout);
+	fputs("\n", stdout);
+}
+
+int
+tcpconnect(char *host)
+{
+	struct addrinfo hints, *ai, *aitop;
+	char strport[NI_MAXSERV];
+	int gaierr, s = -1;
+
+	snprintf(strport, sizeof strport, "%d", PORT);
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = family;
+	hints.ai_socktype = SOCK_STREAM;
+	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
+		fatal("getaddrinfo %s: %s", host, gai_strerror(gaierr));
+	for (ai = aitop; ai; ai = ai->ai_next) {
+		s = socket(ai->ai_family, SOCK_STREAM, 0);
+		if (s < 0) {
+			error("socket: %s", strerror(errno));
+			continue;
+		}
+		if (fcntl(s, F_SETFL, O_NDELAY) < 0)
+			fatal("F_SETFL: %s", strerror(errno));
+		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
+		    errno != EINPROGRESS)
+			error("connect (`%s'): %s", host, strerror(errno));
+		else
+			break;
+		close(s);
+		s = -1;
+	}
+	freeaddrinfo(aitop);
+	return s;
+}
+
+int
+conalloc(char *iname, char *oname)
+{
+	int s;
+	char *namebase, *name, *namelist;
+
+	namebase = namelist = xstrdup(iname);
+
+	do {
+		name = xstrsep(&namelist, ",");
+		if (!name) {
+			free(namebase);
+			return (-1);
+		}
+	} while ((s = tcpconnect(name)) < 0);
+
+	if (s >= maxfd)
+		fatal("conalloc: fdno %d too high\n", s);
+	if (fdcon[s].c_status)
+		fatal("conalloc: attempt to reuse fdno %d\n", s);
+
+	fdcon[s].c_fd = s;
+	fdcon[s].c_status = CS_CON;
+	fdcon[s].c_namebase = namebase;
+	fdcon[s].c_name = name;
+	fdcon[s].c_namelist = namelist;
+	fdcon[s].c_output_name = xstrdup(oname);
+	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
+	fdcon[s].c_len = 4;
+	fdcon[s].c_off = 0;
+	gettimeofday(&fdcon[s].c_tv, NULL);
+	fdcon[s].c_tv.tv_sec += timeout;
+	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
+	FD_SET(s, &read_wait);
+	ncon++;
+	return (s);
+}
+
+void
+confree(int s)
+{
+	close(s);
+	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
+		fatal("confree: attempt to free bad fdno %d\n", s);
+	free(fdcon[s].c_namebase);
+	free(fdcon[s].c_output_name);
+	if (fdcon[s].c_status == CS_KEYS)
+		free(fdcon[s].c_data);
+	fdcon[s].c_status = CS_UNUSED;
+	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
+	FD_CLR(s, &read_wait);
+	ncon--;
+}
+
+void
+contouch(int s)
+{
+	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
+	gettimeofday(&fdcon[s].c_tv, NULL);
+	fdcon[s].c_tv.tv_sec += timeout;
+	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
+}
+
+int
+conrecycle(int s)
+{
+	int ret;
+	con *c = &fdcon[s];
+	char *iname, *oname;
+
+	iname = xstrdup(c->c_namelist);
+	oname = c->c_output_name;
+	c->c_output_name = NULL;/* prevent it from being freed */
+	confree(s);
+	ret = conalloc(iname, oname);
+	free(iname);
+	return (ret);
+}
+
+void
+congreet(int s)
+{
+	char buf[80];
+	int n;
+	con *c = &fdcon[s];
+
+	n = read(s, buf, sizeof(buf));
+	if (n < 0) {
+		if (errno != ECONNREFUSED)
+			error("read (%s): %s", c->c_name, strerror(errno));
+		conrecycle(s);
+		return;
+	}
+	if (buf[n - 1] != '\n') {
+		error("%s: bad greeting", c->c_name);
+		confree(s);
+		return;
+	}
+	buf[n - 1] = '\0';
+	fprintf(stderr, "# %s %s\n", c->c_name, buf);
+	n = snprintf(buf, sizeof buf, "SSH-1.5-OpenSSH-keyscan\r\n");
+	if (write(s, buf, n) != n) {
+		error("write (%s): %s", c->c_name, strerror(errno));
+		confree(s);
+		return;
+	}
+	c->c_status = CS_SIZE;
+	contouch(s);
+}
+
+void
+conread(int s)
+{
+	int n;
+	con *c = &fdcon[s];
+
+	if (c->c_status == CS_CON) {
+		congreet(s);
+		return;
+	}
+	n = read(s, c->c_data + c->c_off, c->c_len - c->c_off);
+	if (n < 0) {
+		error("read (%s): %s", c->c_name, strerror(errno));
+		confree(s);
+		return;
+	}
+	c->c_off += n;
+
+	if (c->c_off == c->c_len)
+		switch (c->c_status) {
+		case CS_SIZE:
+			c->c_plen = htonl(c->c_plen);
+			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
+			c->c_off = 0;
+			c->c_data = xmalloc(c->c_len);
+			c->c_status = CS_KEYS;
+			break;
+		case CS_KEYS:
+			keyprint(c->c_name, c->c_output_name, c->c_data, c->c_plen);
+			confree(s);
+			return;
+			break;
+		default:
+			fatal("conread: invalid status %d\n", c->c_status);
+			break;
+		}
+
+	contouch(s);
+}
+
+void
+conloop(void)
+{
+	fd_set r, e;
+	struct timeval seltime, now;
+	int i;
+	con *c;
+
+	gettimeofday(&now, NULL);
+	c = tq.tqh_first;
+
+	if (c &&
+	    (c->c_tv.tv_sec > now.tv_sec ||
+	     (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
+		seltime = c->c_tv;
+		seltime.tv_sec -= now.tv_sec;
+		seltime.tv_usec -= now.tv_usec;
+		if ((int) seltime.tv_usec < 0) {
+			seltime.tv_usec += 1000000;
+			seltime.tv_sec--;
+		}
+	} else
+		seltime.tv_sec = seltime.tv_usec = 0;
+
+	r = e = read_wait;
+	select(maxfd, &r, NULL, &e, &seltime);
+	for (i = 0; i < maxfd; i++)
+		if (FD_ISSET(i, &e)) {
+			error("%s: exception!", fdcon[i].c_name);
+			confree(i);
+		} else if (FD_ISSET(i, &r))
+			conread(i);
+
+	c = tq.tqh_first;
+	while (c &&
+	       (c->c_tv.tv_sec < now.tv_sec ||
+	        (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
+		int s = c->c_fd;
+		c = c->c_link.tqe_next;
+		conrecycle(s);
+	}
+}
+
+char *
+nexthost(int argc, char **argv)
+{
+	static Linebuf *lb;
+
+	for (;;) {
+		if (!lb) {
+			if (argno >= argc)
+				return (NULL);
+			if (argv[argno][0] != '-')
+				return (argv[argno++]);
+			if (!strcmp(argv[argno], "--")) {
+				if (++argno >= argc)
+					return (NULL);
+				return (argv[argno++]);
+			} else if (!strncmp(argv[argno], "-f", 2)) {
+				char *fname;
+				if (argv[argno][2])
+					fname = &argv[argno++][2];
+				else if (++argno >= argc) {
+					error("missing filename for `-f'");
+					return (NULL);
+				} else
+					fname = argv[argno++];
+				if (!strcmp(fname, "-"))
+					fname = NULL;
+				lb = Linebuf_alloc(fname, warn);
+			} else
+				error("ignoring invalid/misplaced option `%s'", argv[argno++]);
+		} else {
+			char *line;
+			line = getline(lb);
+			if (line)
+				return (line);
+			Linebuf_free(lb);
+			lb = NULL;
+		}
+	}
+}
+
+static void
+usage(void)
+{
+	fatal("usage: %s [-t timeout] { [--] host | -f file } ...\n", prog);
+	return;
+}
+
+int
+main(int argc, char **argv)
+{
+	char *host = NULL;
+
+	TAILQ_INIT(&tq);
+
+	if ((prog = strrchr(argv[0], '/')))
+		prog++;
+	else
+		prog = argv[0];
+
+	if (argc <= argno)
+		usage();
+
+	if (argv[1][0] == '-' && argv[1][1] == 't') {
+		argno++;
+		if (argv[1][2])
+			timeout = atoi(&argv[1][2]);
+		else {
+			if (argno >= argc)
+				usage();
+			timeout = atoi(argv[argno++]);
+		}
+		if (timeout <= 0)
+			usage();
+	}
+	if (argc <= argno)
+		usage();
+
+	maxfd = fdlim_get(1);
+	if (maxfd < 0)
+		fatal("%s: fdlim_get: bad value\n", prog);
+	if (maxfd > MAXMAXFD)
+		maxfd = MAXMAXFD;
+	if (maxcon <= 0)
+		fatal("%s: not enough file descriptors\n", prog);
+	if (maxfd > fdlim_get(0))
+		fdlim_set(maxfd);
+	fdcon = xmalloc(maxfd * sizeof(con));
+
+	do {
+		while (ncon < maxcon) {
+			char *name;
+
+			host = nexthost(argc, argv);
+			if (host == NULL)
+				break;
+			name = strnnsep(&host, " \t\n");
+			conalloc(name, *host ? host : name);
+		}
+		conloop();
+	} while (host);
+	while (ncon > 0)
+		conloop();
+
+	return (0);
+}