1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1983, 1991, 1993, 1994
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30#include <sys/filio.h>
31#include <sys/ioccom.h>
32#include <sys/param.h>
33#include <sys/stat.h>
34#include <sys/socket.h>
35#include <sys/sysctl.h>
36#include <sys/ucred.h>
37#include <sys/uio.h>
38#include <sys/utsname.h>
39
40#include <ctype.h>
41#include <err.h>
42#include <errno.h>
43#include <fcntl.h>
44#include <limits.h>
45#include <pwd.h>
46#include <signal.h>
47#include <stdlib.h>
48#include <string.h>
49#include <sysexits.h>
50#include <syslog.h>
51#include <unistd.h>
52
53#include "inetd.h"
54
55static void	chargen_dg(int, struct servtab *);
56static void	chargen_stream(int, struct servtab *);
57static void	daytime_dg(int, struct servtab *);
58static void	daytime_stream(int, struct servtab *);
59static void	discard_dg(int, struct servtab *);
60static void	discard_stream(int, struct servtab *);
61static void	echo_dg(int, struct servtab *);
62static void	echo_stream(int, struct servtab *);
63static int	get_line(int, char *, int);
64static void	iderror(int, int, int, const char *);
65static void	ident_stream(int, struct servtab *);
66static void	initring(void);
67static uint32_t	machtime(void);
68static void	machtime_dg(int, struct servtab *);
69static void	machtime_stream(int, struct servtab *);
70
71static char ring[128];
72static char *endring;
73
74struct biltin biltins[] = {
75	/* Echo received data */
76	{ "echo",	SOCK_STREAM,	1, -1,	echo_stream },
77	{ "echo",	SOCK_DGRAM,	0, 1,	echo_dg },
78
79	/* Internet /dev/null */
80	{ "discard",	SOCK_STREAM,	1, -1,	discard_stream },
81	{ "discard",	SOCK_DGRAM,	0, 1,	discard_dg },
82
83	/* Return 32 bit time since 1900 */
84	{ "time",	SOCK_STREAM,	0, -1,	machtime_stream },
85	{ "time",	SOCK_DGRAM,	0, 1,	machtime_dg },
86
87	/* Return human-readable time */
88	{ "daytime",	SOCK_STREAM,	0, -1,	daytime_stream },
89	{ "daytime",	SOCK_DGRAM,	0, 1,	daytime_dg },
90
91	/* Familiar character generator */
92	{ "chargen",	SOCK_STREAM,	1, -1,	chargen_stream },
93	{ "chargen",	SOCK_DGRAM,	0, 1,	chargen_dg },
94
95	{ "tcpmux",	SOCK_STREAM,	1, -1,	(bi_fn_t *)tcpmux },
96
97	{ "auth",	SOCK_STREAM,	1, -1,	ident_stream },
98
99	{ NULL,		0,		0, 0,	NULL }
100};
101
102/*
103 * RFC864 Character Generator Protocol. Generates character data without
104 * any regard for input.
105 */
106
107static void
108initring(void)
109{
110	int i;
111
112	endring = ring;
113
114	for (i = 0; i <= 128; ++i)
115		if (isprint(i))
116			*endring++ = i;
117}
118
119/* Character generator
120 * The RFC says that we should send back a random number of
121 * characters chosen from the range 0 to 512. We send LINESIZ+2.
122 */
123/* ARGSUSED */
124static void
125chargen_dg(int s, struct servtab *sep)
126{
127	struct sockaddr_storage ss;
128	static char *rs;
129	int len;
130	socklen_t size;
131	char text[LINESIZ+2];
132
133	if (endring == NULL)
134		initring();
135	if (rs == NULL)
136		rs = ring;
137
138	size = sizeof(ss);
139	if (recvfrom(s, text, sizeof(text), 0,
140		     (struct sockaddr *)&ss, &size) < 0)
141		return;
142
143	if (check_loop((struct sockaddr *)&ss, sep))
144		return;
145
146	if ((len = endring - rs) >= LINESIZ)
147		memmove(text, rs, LINESIZ);
148	else {
149		memmove(text, rs, len);
150		memmove(text + len, ring, LINESIZ - len);
151	}
152	if (++rs == endring)
153		rs = ring;
154	text[LINESIZ] = '\r';
155	text[LINESIZ + 1] = '\n';
156	(void) sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size);
157}
158
159/* Character generator */
160/* ARGSUSED */
161static void
162chargen_stream(int s, struct servtab *sep)
163{
164	int len;
165	char *rs, text[LINESIZ+2];
166
167	inetd_setproctitle(sep->se_service, s);
168
169	if (!endring)
170		initring();
171
172	text[LINESIZ] = '\r';
173	text[LINESIZ + 1] = '\n';
174	for (rs = ring;;) {
175		if ((len = endring - rs) >= LINESIZ)
176			memmove(text, rs, LINESIZ);
177		else {
178			memmove(text, rs, len);
179			memmove(text + len, ring, LINESIZ - len);
180		}
181		if (++rs == endring)
182			rs = ring;
183		if (write(s, text, sizeof(text)) != sizeof(text))
184			break;
185	}
186	exit(0);
187}
188
189/*
190 * RFC867 Daytime Protocol. Sends the current date and time as an ascii
191 * character string without any regard for input.
192 */
193
194/* Return human-readable time of day */
195/* ARGSUSED */
196static void
197daytime_dg(int s, struct servtab *sep)
198{
199	char buffer[256];
200	time_t now;
201	struct sockaddr_storage ss;
202	socklen_t size;
203
204	now = time((time_t *) 0);
205
206	size = sizeof(ss);
207	if (recvfrom(s, buffer, sizeof(buffer), 0,
208		     (struct sockaddr *)&ss, &size) < 0)
209		return;
210
211	if (check_loop((struct sockaddr *)&ss, sep))
212		return;
213
214	(void) sprintf(buffer, "%.24s\r\n", ctime(&now));
215	(void) sendto(s, buffer, strlen(buffer), 0,
216		      (struct sockaddr *)&ss, size);
217}
218
219/* Return human-readable time of day */
220/* ARGSUSED */
221static void
222daytime_stream(int s, struct servtab *sep __unused)
223{
224	char buffer[256];
225	time_t now;
226
227	now = time((time_t *) 0);
228
229	(void) sprintf(buffer, "%.24s\r\n", ctime(&now));
230	(void) send(s, buffer, strlen(buffer), MSG_EOF);
231}
232
233/*
234 * RFC863 Discard Protocol. Any data received is thrown away and no response
235 * is sent.
236 */
237
238/* Discard service -- ignore data */
239/* ARGSUSED */
240static void
241discard_dg(int s, struct servtab *sep __unused)
242{
243	char buffer[BUFSIZE];
244
245	(void) read(s, buffer, sizeof(buffer));
246}
247
248/* Discard service -- ignore data */
249/* ARGSUSED */
250static void
251discard_stream(int s, struct servtab *sep)
252{
253	int ret;
254	char buffer[BUFSIZE];
255
256	inetd_setproctitle(sep->se_service, s);
257	while (1) {
258		while ((ret = read(s, buffer, sizeof(buffer))) > 0)
259			;
260		if (ret == 0 || errno != EINTR)
261			break;
262	}
263	exit(0);
264}
265
266/*
267 * RFC862 Echo Protocol. Any data received is sent back to the sender as
268 * received.
269 */
270
271/* Echo service -- echo data back */
272/* ARGSUSED */
273static void
274echo_dg(int s, struct servtab *sep)
275{
276	char buffer[65536]; /* Should be sizeof(max datagram). */
277	int i;
278	socklen_t size;
279	struct sockaddr_storage ss;
280
281	size = sizeof(ss);
282	if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
283			  (struct sockaddr *)&ss, &size)) < 0)
284		return;
285
286	if (check_loop((struct sockaddr *)&ss, sep))
287		return;
288
289	(void) sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size);
290}
291
292/* Echo service -- echo data back */
293/* ARGSUSED */
294static void
295echo_stream(int s, struct servtab *sep)
296{
297	char buffer[BUFSIZE];
298	int i;
299
300	inetd_setproctitle(sep->se_service, s);
301	while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
302	    write(s, buffer, i) > 0)
303		;
304	exit(0);
305}
306
307/*
308 * RFC1413 Identification Protocol. Given a TCP port number pair, return a
309 * character string which identifies the owner of that connection on the
310 * server's system. Extended to allow for ~/.fakeid support and ~/.noident
311 * support.
312 */
313
314/* RFC 1413 says the following are the only errors you can return. */
315#define ID_INVALID	"INVALID-PORT"	/* Port number improperly specified. */
316#define ID_NOUSER	"NO-USER"	/* Port not in use/not identifiable. */
317#define ID_HIDDEN	"HIDDEN-USER"	/* Hidden at user's request. */
318#define ID_UNKNOWN	"UNKNOWN-ERROR"	/* Everything else. */
319
320/* Generic ident_stream error-sending func */
321/* ARGSUSED */
322static void
323iderror(int lport, int fport, int s, const char *er)
324{
325	char *p;
326
327	asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er);
328	if (p == NULL) {
329		syslog(LOG_ERR, "asprintf: %m");
330		exit(EX_OSERR);
331	}
332	send(s, p, strlen(p), MSG_EOF);
333	free(p);
334
335	exit(0);
336}
337
338/* Ident service (AKA "auth") */
339/* ARGSUSED */
340static void
341ident_stream(int s, struct servtab *sep)
342{
343	struct utsname un;
344	struct stat sb;
345	struct sockaddr_in sin4[2];
346#ifdef INET6
347	struct sockaddr_in6 sin6[2];
348#endif
349	struct sockaddr_storage ss[2];
350	struct xucred uc;
351	struct timeval tv = {
352		10,
353		0
354	}, to;
355	struct passwd *pw = NULL;
356	fd_set fdset;
357	char buf[BUFSIZE], *p, **av, *osname = NULL, e;
358	char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */
359	socklen_t socklen;
360	ssize_t ssize;
361	size_t size, bufsiz;
362	int c, fflag = 0, nflag = 0, rflag = 0, argc = 0;
363	int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen;
364	u_short lport, fport;
365
366	inetd_setproctitle(sep->se_service, s);
367	/*
368	 * Reset getopt() since we are a fork() but not an exec() from
369	 * a parent which used getopt() already.
370	 */
371	optind = 1;
372	optreset = 1;
373	/*
374	 * Take the internal argument vector and count it out to make an
375	 * argument count for getopt. This can be used for any internal
376	 * service to read arguments and use getopt() easily.
377	 */
378	for (av = sep->se_argv; *av; av++)
379		argc++;
380	if (argc) {
381		int sec, usec;
382		size_t i;
383		u_int32_t rnd32;
384
385		while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1)
386			switch (c) {
387			case 'd':
388				if (!gflag)
389					strlcpy(idbuf, optarg, sizeof(idbuf));
390				break;
391			case 'f':
392				fflag = 1;
393				break;
394			case 'F':
395				fflag = 1;
396				Fflag=1;
397				break;
398			case 'g':
399				gflag = 1;
400				rnd32 = 0;	/* Shush, compiler. */
401				/*
402				 * The number of bits in "rnd32" divided
403				 * by the number of bits needed per iteration
404				 * gives a more optimal way to reload the
405				 * random number only when necessary.
406				 *
407				 * 32 bits from arc4random corresponds to
408				 * about 6 base-36 digits, so we reseed every 6.
409				 */
410				for (i = 0; i < sizeof(idbuf) - 1; i++) {
411					static const char *const base36 =
412					    "0123456789"
413					    "abcdefghijklmnopqrstuvwxyz";
414					if (i % 6 == 0)
415						rnd32 = arc4random();
416					idbuf[i] = base36[rnd32 % 36];
417					rnd32 /= 36;
418				}
419				idbuf[i] = '\0';
420				break;
421			case 'i':
422				iflag = 1;
423				break;
424			case 'n':
425				nflag = 1;
426				break;
427			case 'o':
428				osname = optarg;
429				break;
430			case 'r':
431				rflag = 1;
432				break;
433			case 't':
434				switch (sscanf(optarg, "%d.%d", &sec, &usec)) {
435				case 2:
436					tv.tv_usec = usec;
437					/* FALLTHROUGH */
438				case 1:
439					tv.tv_sec = sec;
440					break;
441				default:
442					if (debug)
443						warnx("bad -t argument");
444					break;
445				}
446				break;
447			default:
448				break;
449			}
450	}
451	if (osname == NULL) {
452		if (uname(&un) == -1)
453			iderror(0, 0, s, ID_UNKNOWN);
454		osname = un.sysname;
455	}
456
457	/*
458	 * We're going to prepare for and execute reception of a
459	 * packet of data from the user. The data is in the format
460	 * "local_port , foreign_port\r\n" (with local being the
461	 * server's port and foreign being the client's.)
462	 */
463	gettimeofday(&to, NULL);
464	to.tv_sec += tv.tv_sec;
465	to.tv_usec += tv.tv_usec;
466	if (to.tv_usec >= 1000000) {
467		to.tv_usec -= 1000000;
468		to.tv_sec++;
469	}
470
471	size = 0;
472	bufsiz = sizeof(buf) - 1;
473	FD_ZERO(&fdset);
474 	while (bufsiz > 0) {
475		gettimeofday(&tv, NULL);
476		tv.tv_sec = to.tv_sec - tv.tv_sec;
477		tv.tv_usec = to.tv_usec - tv.tv_usec;
478		if (tv.tv_usec < 0) {
479			tv.tv_usec += 1000000;
480			tv.tv_sec--;
481		}
482		if (tv.tv_sec < 0)
483			break;
484		FD_SET(s, &fdset);
485		if (select(s + 1, &fdset, NULL, NULL, &tv) == -1)
486			iderror(0, 0, s, ID_UNKNOWN);
487		if (ioctl(s, FIONREAD, &onreadlen) == -1)
488			iderror(0, 0, s, ID_UNKNOWN);
489		if ((size_t)onreadlen > bufsiz)
490			onreadlen = bufsiz;
491		ssize = read(s, &buf[size], (size_t)onreadlen);
492		if (ssize == -1)
493			iderror(0, 0, s, ID_UNKNOWN);
494		else if (ssize == 0)
495			break;
496		bufsiz -= ssize;
497		size += ssize;
498		if (memchr(&buf[size - ssize], '\n', ssize) != NULL)
499			break;
500 	}
501	buf[size] = '\0';
502	/* Read two characters, and check for a delimiting character */
503	if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e))
504		iderror(0, 0, s, ID_INVALID);
505
506	/* Send garbage? */
507	if (gflag)
508		goto printit;
509
510	/*
511	 * If not "real" (-r), send a HIDDEN-USER error for everything.
512	 * If -d is used to set a fallback username, this is used to
513	 * override it, and the fallback is returned instead.
514	 */
515	if (!rflag) {
516		if (*idbuf == '\0')
517			iderror(lport, fport, s, ID_HIDDEN);
518		goto printit;
519	}
520
521	/*
522	 * We take the input and construct an array of two sockaddr_ins
523	 * which contain the local address information and foreign
524	 * address information, respectively, used to look up the
525	 * credentials for the socket (which are returned by the
526	 * sysctl "net.inet.tcp.getcred" when we call it.)
527	 */
528	socklen = sizeof(ss[0]);
529	if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1)
530		iderror(lport, fport, s, ID_UNKNOWN);
531	socklen = sizeof(ss[1]);
532	if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1)
533		iderror(lport, fport, s, ID_UNKNOWN);
534	if (ss[0].ss_family != ss[1].ss_family)
535		iderror(lport, fport, s, ID_UNKNOWN);
536	size = sizeof(uc);
537	switch (ss[0].ss_family) {
538	case AF_INET:
539		sin4[0] = *(struct sockaddr_in *)&ss[0];
540		sin4[0].sin_port = htons(lport);
541		sin4[1] = *(struct sockaddr_in *)&ss[1];
542		sin4[1].sin_port = htons(fport);
543		if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4,
544				 sizeof(sin4)) == -1)
545			getcredfail = errno;
546		break;
547#ifdef INET6
548	case AF_INET6:
549		sin6[0] = *(struct sockaddr_in6 *)&ss[0];
550		sin6[0].sin6_port = htons(lport);
551		sin6[1] = *(struct sockaddr_in6 *)&ss[1];
552		sin6[1].sin6_port = htons(fport);
553		if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6,
554				 sizeof(sin6)) == -1)
555			getcredfail = errno;
556		break;
557#endif
558	default: /* should not reach here */
559		getcredfail = EAFNOSUPPORT;
560		break;
561	}
562	if (getcredfail != 0 || uc.cr_version != XUCRED_VERSION) {
563		if (*idbuf == '\0')
564			iderror(lport, fport, s,
565			    getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN);
566		goto printit;
567	}
568
569	/* Look up the pw to get the username and home directory*/
570	errno = 0;
571	pw = getpwuid(uc.cr_uid);
572	if (pw == NULL)
573		iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN);
574
575	if (iflag)
576		snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid);
577	else
578		strlcpy(idbuf, pw->pw_name, sizeof(idbuf));
579
580	/*
581	 * If enabled, we check for a file named ".noident" in the user's
582	 * home directory. If found, we return HIDDEN-USER.
583	 */
584	if (nflag) {
585		if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1)
586			iderror(lport, fport, s, ID_UNKNOWN);
587		if (lstat(p, &sb) == 0) {
588			free(p);
589			iderror(lport, fport, s, ID_HIDDEN);
590		}
591		free(p);
592	}
593
594	/*
595	 * Here, if enabled, we read a user's ".fakeid" file in their
596	 * home directory. It consists of a line containing the name
597	 * they want.
598	 */
599	if (fflag) {
600		int fakeid_fd;
601
602		/*
603		 * Here we set ourself to effectively be the user, so we don't
604		 * open any files we have no permission to open, especially
605		 * symbolic links to sensitive root-owned files or devices.
606		 */
607		if (initgroups(pw->pw_name, pw->pw_gid) == -1)
608			iderror(lport, fport, s, ID_UNKNOWN);
609		if (seteuid(pw->pw_uid) == -1)
610			iderror(lport, fport, s, ID_UNKNOWN);
611		/*
612		 * We can't stat() here since that would be a race
613		 * condition.
614		 * Therefore, we open the file we have permissions to open
615		 * and if it's not a regular file, we close it and end up
616		 * returning the user's real username.
617		 */
618		if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1)
619			iderror(lport, fport, s, ID_UNKNOWN);
620		fakeid_fd = open(p, O_RDONLY | O_NONBLOCK);
621		free(p);
622		if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 ||
623		    !S_ISREG(sb.st_mode))
624			goto fakeid_fail;
625
626		if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0)
627			goto fakeid_fail;
628		buf[ssize] = '\0';
629
630		/*
631		 * Usually, the file will have the desired identity
632		 * in the form "identity\n". Allow for leading white
633		 * space and trailing white space/end of line.
634		 */
635		p = buf;
636		p += strspn(p, " \t");
637		p[strcspn(p, " \t\r\n")] = '\0';
638		if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */
639			p[MAXLOGNAME - 1] = '\0';
640
641		/*
642		 * If the name is a zero-length string or matches it
643		 * the id or name of another user (unless permitted by -F)
644		 * then it is invalid.
645		 */
646		if (*p == '\0')
647			goto fakeid_fail;
648		if (!Fflag) {
649			if (iflag) {
650				const char *errstr;
651				uid_t uid;
652
653				uid = strtonum(p, 0, UID_MAX, &errstr);
654				if (errstr != NULL)
655					goto fakeid_fail;
656
657				if (getpwuid(uid) != NULL)
658					goto fakeid_fail;
659			} else {
660				if (getpwnam(p) != NULL)
661					goto fakeid_fail;
662			}
663		}
664
665		strlcpy(idbuf, p, sizeof(idbuf));
666
667fakeid_fail:
668		if (fakeid_fd != -1)
669			close(fakeid_fd);
670	}
671
672printit:
673	/* Finally, we make and send the reply. */
674	if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname,
675	    idbuf) == -1) {
676		syslog(LOG_ERR, "asprintf: %m");
677		exit(EX_OSERR);
678	}
679	send(s, p, strlen(p), MSG_EOF);
680	free(p);
681
682	exit(0);
683}
684
685/*
686 * RFC738/868 Time Server.
687 * Return a machine readable date and time, in the form of the
688 * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
689 * returns the number of seconds since midnight, Jan 1, 1970,
690 * we must add 2208988800 seconds to this figure to make up for
691 * some seventy years Bell Labs was asleep.
692 */
693
694static uint32_t
695machtime(void)
696{
697
698#define	OFFSET ((uint32_t)25567 * 24*60*60)
699	return (htonl((uint32_t)(time(NULL) + OFFSET)));
700#undef OFFSET
701}
702
703/* ARGSUSED */
704static void
705machtime_dg(int s, struct servtab *sep)
706{
707	uint32_t result;
708	struct sockaddr_storage ss;
709	socklen_t size;
710
711	size = sizeof(ss);
712	if (recvfrom(s, (char *)&result, sizeof(result), 0,
713		     (struct sockaddr *)&ss, &size) < 0)
714		return;
715
716	if (check_loop((struct sockaddr *)&ss, sep))
717		return;
718
719	result = machtime();
720	(void) sendto(s, (char *) &result, sizeof(result), 0,
721		      (struct sockaddr *)&ss, size);
722}
723
724/* ARGSUSED */
725static void
726machtime_stream(int s, struct servtab *sep __unused)
727{
728	uint32_t result;
729
730	result = machtime();
731	(void) send(s, (char *) &result, sizeof(result), MSG_EOF);
732}
733
734/*
735 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to
736 * services based on the service name sent.
737 *
738 *  Based on TCPMUX.C by Mark K. Lottor November 1988
739 *  sri-nic::ps:<mkl>tcpmux.c
740 */
741
742#define MAX_SERV_LEN	(256+2)		/* 2 bytes for \r\n */
743#define strwrite(fd, buf)	(void) write(fd, buf, sizeof(buf)-1)
744
745static int		/* # of characters up to \r,\n or \0 */
746get_line(int fd, char *buf, int len)
747{
748	int count = 0, n;
749	struct sigaction sa;
750
751	sa.sa_flags = 0;
752	sigemptyset(&sa.sa_mask);
753	sa.sa_handler = SIG_DFL;
754	sigaction(SIGALRM, &sa, (struct sigaction *)0);
755	do {
756		alarm(10);
757		n = read(fd, buf, len-count);
758		alarm(0);
759		if (n == 0)
760			return (count);
761		if (n < 0)
762			return (-1);
763		while (--n >= 0) {
764			if (*buf == '\r' || *buf == '\n' || *buf == '\0')
765				return (count);
766			count++;
767			buf++;
768		}
769	} while (count < len);
770	return (count);
771}
772
773struct servtab *
774tcpmux(int s)
775{
776	struct servtab *sep;
777	char service[MAX_SERV_LEN+1];
778	int len;
779
780	/* Get requested service name */
781	if ((len = get_line(s, service, MAX_SERV_LEN)) < 0) {
782		strwrite(s, "-Error reading service name\r\n");
783		return (NULL);
784	}
785	service[len] = '\0';
786
787	if (debug)
788		warnx("tcpmux: someone wants %s", service);
789
790	/*
791	 * Help is a required command, and lists available services,
792	 * one per line.
793	 */
794	if (!strcasecmp(service, "help")) {
795		for (sep = servtab; sep; sep = sep->se_next) {
796			if (!ISMUX(sep))
797				continue;
798			(void)write(s,sep->se_service,strlen(sep->se_service));
799			strwrite(s, "\r\n");
800		}
801		return (NULL);
802	}
803
804	/* Try matching a service in inetd.conf with the request */
805	for (sep = servtab; sep; sep = sep->se_next) {
806		if (!ISMUX(sep))
807			continue;
808		if (!strcasecmp(service, sep->se_service)) {
809			if (ISMUXPLUS(sep)) {
810				strwrite(s, "+Go\r\n");
811			}
812			return (sep);
813		}
814	}
815	strwrite(s, "-Service not available\r\n");
816	return (NULL);
817}
818