1/* $OpenBSD: netcat.c,v 1.130 2015/07/26 19:12:28 chl Exp $ */
2/*
3 * Copyright (c) 2001 Eric Jackson <ericj@monkey.org>
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *   notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *   notice, this list of conditions and the following disclaimer in the
13 *   documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *   derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31/*
32 * Re-written nc(1) for OpenBSD. Original implementation by
33 * *Hobbit* <hobbit@avian.org>.
34 */
35
36#include <errno.h>
37#include <stdio.h>
38#include <sys/arb.h>
39#include <sys/limits.h>
40#include <sys/types.h>
41#include <sys/sbuf.h>
42#include <sys/socket.h>
43#include <sys/sysctl.h>
44#include <sys/qmath.h>
45#include <sys/stats.h>
46#include <sys/time.h>
47#include <sys/uio.h>
48#include <sys/un.h>
49
50#include <netinet/in.h>
51#ifdef IPSEC
52#include <netipsec/ipsec.h>
53#endif
54#include <netinet/tcp.h>
55#include <netinet/ip.h>
56#include <arpa/telnet.h>
57
58#include <err.h>
59#include <getopt.h>
60#include <fcntl.h>
61#include <limits.h>
62#include <netdb.h>
63#include <poll.h>
64#include <signal.h>
65#include <stdarg.h>
66#include <stdlib.h>
67#include <string.h>
68#include <unistd.h>
69#include "atomicio.h"
70
71#ifndef SUN_LEN
72#define SUN_LEN(su) \
73	(sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))
74#endif
75
76#define PORT_MAX	65535
77#define PORT_MAX_LEN	6
78#define UNIX_DG_TMP_SOCKET_SIZE	19
79
80#define POLL_STDIN 0
81#define POLL_NETOUT 1
82#define POLL_NETIN 2
83#define POLL_STDOUT 3
84#define BUFSIZE 16384
85
86/* Command Line Options */
87int	dflag;					/* detached, no stdin */
88int	Fflag;					/* fdpass sock to stdout */
89unsigned int iflag;				/* Interval Flag */
90int	kflag;					/* More than one connect */
91int	lflag;					/* Bind to local port */
92int	FreeBSD_Mflag;				/* Measure using stats(3) */
93int	Nflag;					/* shutdown() network socket */
94int	nflag;					/* Don't do name look up */
95int	FreeBSD_Oflag;				/* Do not use TCP options */
96char   *Pflag;					/* Proxy username */
97char   *pflag;					/* Localport flag */
98int	rflag;					/* Random ports flag */
99char   *sflag;					/* Source Address */
100int	tflag;					/* Telnet Emulation */
101int	uflag;					/* UDP - Default to TCP */
102int	vflag;					/* Verbosity */
103int	xflag;					/* Socks proxy */
104int	zflag;					/* Port Scan Flag */
105int	Dflag;					/* sodebug */
106int	Iflag;					/* TCP receive buffer size */
107int	Oflag;					/* TCP send buffer size */
108int	Sflag;					/* TCP MD5 signature option */
109int	Tflag = -1;				/* IP Type of Service */
110int	rtableid = -1;
111
112int timeout = -1;
113int family = AF_UNSPEC;
114char *portlist[PORT_MAX+1];
115char *unix_dg_tmp_socket;
116
117void	atelnet(int, unsigned char *, unsigned int);
118void	build_ports(char *);
119void	help(void);
120int	local_listen(char *, char *, struct addrinfo);
121void	readwrite(int);
122void	fdpass(int nfd) __attribute__((noreturn));
123int	remote_connect(const char *, const char *, struct addrinfo);
124int	timeout_connect(int, const struct sockaddr *, socklen_t);
125int	socks_connect(const char *, const char *, struct addrinfo,
126	    const char *, const char *, struct addrinfo, int, const char *);
127int	udptest(int);
128int	unix_bind(char *);
129int	unix_connect(char *);
130int	unix_listen(char *);
131void	FreeBSD_stats_setup(int);
132void	FreeBSD_stats_print(int);
133void	set_common_sockopts(int, int);
134int	map_tos(char *, int *);
135void	report_connect(const struct sockaddr *, socklen_t);
136void	usage(int);
137ssize_t drainbuf(int, unsigned char *, size_t *);
138ssize_t fillbuf(int, unsigned char *, size_t *);
139
140#ifdef IPSEC
141void	add_ipsec_policy(int, int, char *);
142
143char	*ipsec_policy[2];
144#endif
145
146int
147main(int argc, char *argv[])
148{
149	int ch, s, ret, socksv, ipsec_count;
150	int numfibs;
151	size_t intsize = sizeof(int);
152	char *host, *uport;
153	struct addrinfo hints;
154	struct servent *sv;
155	socklen_t len;
156	struct sockaddr_storage cliaddr;
157	char *proxy;
158	const char *errstr, *proxyhost = "", *proxyport = NULL;
159	struct addrinfo proxyhints;
160	char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE];
161	struct option longopts[] = {
162		{ "no-tcpopt",	no_argument,	&FreeBSD_Oflag,	1 },
163		{ NULL,		0,		NULL,		0 }
164	};
165
166	ret = 1;
167	ipsec_count = 0;
168	s = 0;
169	socksv = 5;
170	host = NULL;
171	uport = NULL;
172	sv = NULL;
173
174	signal(SIGPIPE, SIG_IGN);
175
176	while ((ch = getopt_long(argc, argv,
177	    "46DdEe:FhI:i:klMNnoO:P:p:rSs:tT:UuV:vw:X:x:z",
178	    longopts, NULL)) != -1) {
179		switch (ch) {
180		case '4':
181			family = AF_INET;
182			break;
183		case '6':
184			family = AF_INET6;
185			break;
186		case 'U':
187			family = AF_UNIX;
188			break;
189		case 'X':
190			if (strcasecmp(optarg, "connect") == 0)
191				socksv = -1; /* HTTP proxy CONNECT */
192			else if (strcmp(optarg, "4") == 0)
193				socksv = 4; /* SOCKS v.4 */
194			else if (strcmp(optarg, "5") == 0)
195				socksv = 5; /* SOCKS v.5 */
196			else
197				errx(1, "unsupported proxy protocol");
198			break;
199		case 'd':
200			dflag = 1;
201			break;
202		case 'e':
203#ifdef IPSEC
204			ipsec_policy[ipsec_count++ % 2] = optarg;
205#else
206			errx(1, "IPsec support unavailable.");
207#endif
208			break;
209		case 'E':
210#ifdef IPSEC
211			ipsec_policy[0] = "in  ipsec esp/transport//require";
212			ipsec_policy[1] = "out ipsec esp/transport//require";
213#else
214			errx(1, "IPsec support unavailable.");
215#endif
216			break;
217		case 'F':
218			Fflag = 1;
219			break;
220		case 'h':
221			help();
222			break;
223		case 'i':
224			iflag = strtonum(optarg, 0, UINT_MAX, &errstr);
225			if (errstr)
226				errx(1, "interval %s: %s", errstr, optarg);
227			break;
228		case 'k':
229			kflag = 1;
230			break;
231		case 'l':
232			lflag = 1;
233			break;
234		case 'M':
235#ifndef WITH_STATS
236			errx(1, "-M requires stats(3) support");
237#else
238			FreeBSD_Mflag = 1;
239#endif
240			break;
241		case 'N':
242			Nflag = 1;
243			break;
244		case 'n':
245			nflag = 1;
246			break;
247		case 'o':
248			fprintf(stderr, "option -o is deprecated.\n");
249			break;
250		case 'P':
251			Pflag = optarg;
252			break;
253		case 'p':
254			pflag = optarg;
255			break;
256		case 'r':
257			rflag = 1;
258			break;
259		case 's':
260			sflag = optarg;
261			break;
262		case 't':
263			tflag = 1;
264			break;
265		case 'u':
266			uflag = 1;
267			break;
268		case 'V':
269			if (sysctlbyname("net.fibs", &numfibs, &intsize, NULL, 0) == -1)
270				errx(1, "Multiple FIBS not supported");
271			rtableid = (int)strtonum(optarg, 0,
272			    numfibs - 1, &errstr);
273			if (errstr)
274				errx(1, "rtable %s: %s", errstr, optarg);
275			break;
276		case 'v':
277			vflag = 1;
278			break;
279		case 'w':
280			timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr);
281			if (errstr)
282				errx(1, "timeout %s: %s", errstr, optarg);
283			timeout *= 1000;
284			break;
285		case 'x':
286			xflag = 1;
287			if ((proxy = strdup(optarg)) == NULL)
288				err(1, NULL);
289			break;
290		case 'z':
291			zflag = 1;
292			break;
293		case 'D':
294			Dflag = 1;
295			break;
296		case 'I':
297			Iflag = strtonum(optarg, 1, 65536 << 14, &errstr);
298			if (errstr != NULL)
299				errx(1, "TCP receive window %s: %s",
300				    errstr, optarg);
301			break;
302		case 'O':
303			Oflag = strtonum(optarg, 1, 65536 << 14, &errstr);
304			if (errstr != NULL) {
305			    if (strcmp(errstr, "invalid") != 0)
306				errx(1, "TCP send window %s: %s",
307				    errstr, optarg);
308			}
309			break;
310		case 'S':
311			Sflag = 1;
312			break;
313		case 'T':
314			errstr = NULL;
315			errno = 0;
316			if (map_tos(optarg, &Tflag))
317				break;
318			if (strlen(optarg) > 1 && optarg[0] == '0' &&
319			    optarg[1] == 'x')
320				Tflag = (int)strtol(optarg, NULL, 16);
321			else
322				Tflag = (int)strtonum(optarg, 0, 255,
323				    &errstr);
324			if (Tflag < 0 || Tflag > 255 || errstr || errno)
325				errx(1, "illegal tos value %s", optarg);
326			break;
327		default:
328			usage(1);
329		}
330	}
331	argc -= optind;
332	argv += optind;
333
334	/* Cruft to make sure options are clean, and used properly. */
335	if (argv[0] && !argv[1] && family == AF_UNIX) {
336		host = argv[0];
337		uport = NULL;
338	} else if (argv[0] && !argv[1]) {
339		if  (!lflag)
340			usage(1);
341		uport = argv[0];
342		host = NULL;
343	} else if (argv[0] && argv[1]) {
344		host = argv[0];
345		uport = argv[1];
346	} else
347		usage(1);
348
349	if (lflag && sflag)
350		errx(1, "cannot use -s and -l");
351	if (lflag && pflag)
352		errx(1, "cannot use -p and -l");
353	if (lflag && zflag)
354		errx(1, "cannot use -z and -l");
355	if (!lflag && kflag)
356		errx(1, "must use -l with -k");
357
358	/* Get name of temporary socket for unix datagram client */
359	if ((family == AF_UNIX) && uflag && !lflag) {
360		if (sflag) {
361			unix_dg_tmp_socket = sflag;
362		} else {
363			strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX",
364				UNIX_DG_TMP_SOCKET_SIZE);
365			if (mktemp(unix_dg_tmp_socket_buf) == NULL)
366				err(1, "mktemp");
367			unix_dg_tmp_socket = unix_dg_tmp_socket_buf;
368		}
369	}
370
371	/* Initialize addrinfo structure. */
372	if (family != AF_UNIX) {
373		memset(&hints, 0, sizeof(struct addrinfo));
374		hints.ai_family = family;
375		hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
376		hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
377		if (nflag)
378			hints.ai_flags |= AI_NUMERICHOST;
379	}
380
381	if (xflag) {
382		if (uflag)
383			errx(1, "no proxy support for UDP mode");
384
385		if (lflag)
386			errx(1, "no proxy support for listen");
387
388		if (family == AF_UNIX)
389			errx(1, "no proxy support for unix sockets");
390
391		/* XXX IPv6 transport to proxy would probably work */
392		if (family == AF_INET6)
393			errx(1, "no proxy support for IPv6");
394
395		if (sflag)
396			errx(1, "no proxy support for local source address");
397
398		proxyhost = strsep(&proxy, ":");
399		proxyport = proxy;
400
401		memset(&proxyhints, 0, sizeof(struct addrinfo));
402		proxyhints.ai_family = family;
403		proxyhints.ai_socktype = SOCK_STREAM;
404		proxyhints.ai_protocol = IPPROTO_TCP;
405		if (nflag)
406			proxyhints.ai_flags |= AI_NUMERICHOST;
407	}
408
409	if (lflag) {
410		int connfd;
411		ret = 0;
412
413		if (family == AF_UNIX) {
414			if (uflag)
415				s = unix_bind(host);
416			else
417				s = unix_listen(host);
418		}
419
420		/* Allow only one connection at a time, but stay alive. */
421		for (;;) {
422			if (family != AF_UNIX)
423				s = local_listen(host, uport, hints);
424			if (s < 0)
425				err(1, NULL);
426			/*
427			 * For UDP and -k, don't connect the socket, let it
428			 * receive datagrams from multiple socket pairs.
429			 */
430			if (uflag && kflag)
431				readwrite(s);
432			/*
433			 * For UDP and not -k, we will use recvfrom() initially
434			 * to wait for a caller, then use the regular functions
435			 * to talk to the caller.
436			 */
437			else if (uflag && !kflag) {
438				int rv, plen;
439				char buf[16384];
440				struct sockaddr_storage z;
441
442				len = sizeof(z);
443				plen = 2048;
444				rv = recvfrom(s, buf, plen, MSG_PEEK,
445				    (struct sockaddr *)&z, &len);
446				if (rv < 0)
447					err(1, "recvfrom");
448
449				rv = connect(s, (struct sockaddr *)&z, len);
450				if (rv < 0)
451					err(1, "connect");
452
453				if (vflag)
454					report_connect((struct sockaddr *)&z, len);
455
456				readwrite(s);
457			} else {
458				len = sizeof(cliaddr);
459				connfd = accept(s, (struct sockaddr *)&cliaddr,
460				    &len);
461				if (connfd == -1) {
462					/* For now, all errnos are fatal */
463					err(1, "accept");
464				}
465				if (vflag)
466					report_connect((struct sockaddr *)&cliaddr, len);
467
468				if (FreeBSD_Mflag)
469					FreeBSD_stats_setup(connfd);
470				readwrite(connfd);
471				close(connfd);
472			}
473
474			if (family != AF_UNIX)
475				close(s);
476			else if (uflag) {
477				if (connect(s, NULL, 0) < 0)
478					err(1, "connect");
479			}
480
481			if (!kflag)
482				break;
483		}
484	} else if (family == AF_UNIX) {
485		ret = 0;
486
487		if ((s = unix_connect(host)) > 0 && !zflag) {
488			readwrite(s);
489			close(s);
490		} else
491			ret = 1;
492
493		if (uflag)
494			unlink(unix_dg_tmp_socket);
495		exit(ret);
496
497	} else {
498		int i = 0;
499
500		/* Construct the portlist[] array. */
501		build_ports(uport);
502
503		/* Cycle through portlist, connecting to each port. */
504		for (i = 0; portlist[i] != NULL; i++) {
505			if (s)
506				close(s);
507
508			if (xflag)
509				s = socks_connect(host, portlist[i], hints,
510				    proxyhost, proxyport, proxyhints, socksv,
511				    Pflag);
512			else
513				s = remote_connect(host, portlist[i], hints);
514
515			if (s < 0)
516				continue;
517
518			ret = 0;
519			if (vflag || zflag) {
520				/* For UDP, make sure we are connected. */
521				if (uflag) {
522					if (udptest(s) == -1) {
523						ret = 1;
524						continue;
525					}
526				}
527
528				/* Don't look up port if -n. */
529				if (nflag)
530					sv = NULL;
531				else {
532					sv = getservbyport(
533					    ntohs(atoi(portlist[i])),
534					    uflag ? "udp" : "tcp");
535				}
536
537				fprintf(stderr,
538				    "Connection to %s %s port [%s/%s] "
539				    "succeeded!\n", host, portlist[i],
540				    uflag ? "udp" : "tcp",
541				    sv ? sv->s_name : "*");
542			}
543			if (Fflag)
544				fdpass(s);
545			else if (!zflag)
546				readwrite(s);
547		}
548	}
549
550	if (s)
551		close(s);
552
553	exit(ret);
554}
555
556/*
557 * unix_bind()
558 * Returns a unix socket bound to the given path
559 */
560int
561unix_bind(char *path)
562{
563	struct sockaddr_un sun;
564	int s;
565
566	/* Create unix domain socket. */
567	if ((s = socket(AF_UNIX, uflag ? SOCK_DGRAM : SOCK_STREAM,
568	     0)) < 0)
569		return (-1);
570
571	memset(&sun, 0, sizeof(struct sockaddr_un));
572	sun.sun_family = AF_UNIX;
573
574	if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
575	    sizeof(sun.sun_path)) {
576		close(s);
577		errno = ENAMETOOLONG;
578		return (-1);
579	}
580
581	if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
582		close(s);
583		return (-1);
584	}
585	return (s);
586}
587
588/*
589 * unix_connect()
590 * Returns a socket connected to a local unix socket. Returns -1 on failure.
591 */
592int
593unix_connect(char *path)
594{
595	struct sockaddr_un sun;
596	int s;
597
598	if (uflag) {
599		if ((s = unix_bind(unix_dg_tmp_socket)) < 0)
600			return (-1);
601	} else {
602		if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
603			return (-1);
604	}
605	(void)fcntl(s, F_SETFD, FD_CLOEXEC);
606
607	memset(&sun, 0, sizeof(struct sockaddr_un));
608	sun.sun_family = AF_UNIX;
609
610	if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
611	    sizeof(sun.sun_path)) {
612		close(s);
613		errno = ENAMETOOLONG;
614		return (-1);
615	}
616	if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
617		close(s);
618		return (-1);
619	}
620	return (s);
621
622}
623
624/*
625 * unix_listen()
626 * Create a unix domain socket, and listen on it.
627 */
628int
629unix_listen(char *path)
630{
631	int s;
632	if ((s = unix_bind(path)) < 0)
633		return (-1);
634
635	if (listen(s, 5) < 0) {
636		close(s);
637		return (-1);
638	}
639	return (s);
640}
641
642/*
643 * remote_connect()
644 * Returns a socket connected to a remote host. Properly binds to a local
645 * port or source address if needed. Returns -1 on failure.
646 */
647int
648remote_connect(const char *host, const char *port, struct addrinfo hints)
649{
650	struct addrinfo *res, *res0;
651	int s, error, on = 1;
652
653	if ((error = getaddrinfo(host, port, &hints, &res)))
654		errx(1, "getaddrinfo: %s", gai_strerror(error));
655
656	res0 = res;
657	do {
658		if ((s = socket(res0->ai_family, res0->ai_socktype,
659		    res0->ai_protocol)) < 0)
660			continue;
661
662		if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_SETFIB,
663		    &rtableid, sizeof(rtableid)) == -1))
664			err(1, "setsockopt SO_SETFIB");
665
666		/* Bind to a local port or source address if specified. */
667		if (sflag || pflag) {
668			struct addrinfo ahints, *ares;
669
670			/* try IP_BINDANY, but don't insist */
671			setsockopt(s, IPPROTO_IP, IP_BINDANY, &on, sizeof(on));
672			memset(&ahints, 0, sizeof(struct addrinfo));
673			ahints.ai_family = res0->ai_family;
674			ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
675			ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
676			ahints.ai_flags = AI_PASSIVE;
677			if ((error = getaddrinfo(sflag, pflag, &ahints, &ares)))
678				errx(1, "getaddrinfo: %s", gai_strerror(error));
679
680			if (bind(s, (struct sockaddr *)ares->ai_addr,
681			    ares->ai_addrlen) < 0)
682				err(1, "bind failed");
683			freeaddrinfo(ares);
684		}
685
686		set_common_sockopts(s, res0->ai_family);
687
688		if (timeout_connect(s, res0->ai_addr, res0->ai_addrlen) == 0)
689			break;
690		else if (vflag)
691			warn("connect to %s port %s (%s) failed", host, port,
692			    uflag ? "udp" : "tcp");
693
694		close(s);
695		s = -1;
696	} while ((res0 = res0->ai_next) != NULL);
697
698	freeaddrinfo(res);
699
700	return (s);
701}
702
703int
704timeout_connect(int s, const struct sockaddr *name, socklen_t namelen)
705{
706	struct pollfd pfd;
707	socklen_t optlen;
708	int flags, optval;
709	int ret;
710
711	if (timeout != -1) {
712		flags = fcntl(s, F_GETFL, 0);
713		if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1)
714			err(1, "set non-blocking mode");
715	}
716
717	if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) {
718		pfd.fd = s;
719		pfd.events = POLLOUT;
720		if ((ret = poll(&pfd, 1, timeout)) == 1) {
721			optlen = sizeof(optval);
722			if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR,
723			    &optval, &optlen)) == 0) {
724				errno = optval;
725				ret = optval == 0 ? 0 : -1;
726			}
727		} else if (ret == 0) {
728			errno = ETIMEDOUT;
729			ret = -1;
730		} else
731			err(1, "poll failed");
732	}
733
734	if (timeout != -1 && fcntl(s, F_SETFL, flags) == -1)
735		err(1, "restoring flags");
736
737	return (ret);
738}
739
740/*
741 * local_listen()
742 * Returns a socket listening on a local port, binds to specified source
743 * address. Returns -1 on failure.
744 */
745int
746local_listen(char *host, char *port, struct addrinfo hints)
747{
748	struct addrinfo *res, *res0;
749	int s, ret, x = 1;
750	int error;
751
752	/* Allow nodename to be null. */
753	hints.ai_flags |= AI_PASSIVE;
754
755	/*
756	 * In the case of binding to a wildcard address
757	 * default to binding to an ipv4 address.
758	 */
759	if (host == NULL && hints.ai_family == AF_UNSPEC)
760		hints.ai_family = AF_INET;
761
762	if ((error = getaddrinfo(host, port, &hints, &res)))
763		errx(1, "getaddrinfo: %s", gai_strerror(error));
764
765	res0 = res;
766	do {
767		if ((s = socket(res0->ai_family, res0->ai_socktype,
768		    res0->ai_protocol)) < 0)
769			continue;
770
771		if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_SETFIB,
772		    &rtableid, sizeof(rtableid)) == -1))
773			err(1, "setsockopt SO_SETFIB");
774
775		ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x));
776		if (ret == -1)
777			err(1, NULL);
778
779		if (FreeBSD_Oflag) {
780			if (setsockopt(s, IPPROTO_TCP, TCP_NOOPT,
781			    &FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1)
782				err(1, "disable TCP options");
783		}
784
785		set_common_sockopts(s, res0->ai_family);
786
787		if (bind(s, (struct sockaddr *)res0->ai_addr,
788		    res0->ai_addrlen) == 0)
789			break;
790
791		close(s);
792		s = -1;
793	} while ((res0 = res0->ai_next) != NULL);
794
795	if (!uflag && s != -1) {
796		if (listen(s, 1) < 0)
797			err(1, "listen");
798	}
799
800	freeaddrinfo(res);
801
802	return (s);
803}
804
805/*
806 * readwrite()
807 * Loop that polls on the network file descriptor and stdin.
808 */
809void
810readwrite(int net_fd)
811{
812	struct pollfd pfd[4];
813	int stdin_fd = STDIN_FILENO;
814	int stdout_fd = STDOUT_FILENO;
815	unsigned char netinbuf[BUFSIZE];
816	size_t netinbufpos = 0;
817	unsigned char stdinbuf[BUFSIZE];
818	size_t stdinbufpos = 0;
819	int n, num_fds;
820	int stats_printed = 0;
821	ssize_t ret;
822
823	/* don't read from stdin if requested */
824	if (dflag)
825		stdin_fd = -1;
826
827	/* stdin */
828	pfd[POLL_STDIN].fd = stdin_fd;
829	pfd[POLL_STDIN].events = POLLIN;
830
831	/* network out */
832	pfd[POLL_NETOUT].fd = net_fd;
833	pfd[POLL_NETOUT].events = 0;
834
835	/* network in */
836	pfd[POLL_NETIN].fd = net_fd;
837	pfd[POLL_NETIN].events = POLLIN;
838
839	/* stdout */
840	pfd[POLL_STDOUT].fd = stdout_fd;
841	pfd[POLL_STDOUT].events = 0;
842
843	while (1) {
844		/* both inputs are gone, buffers are empty, we are done */
845		if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1
846		    && stdinbufpos == 0 && netinbufpos == 0) {
847			if (FreeBSD_Mflag && !stats_printed)
848				FreeBSD_stats_print(net_fd);
849			close(net_fd);
850			return;
851		}
852		/* both outputs are gone, we can't continue */
853		if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) {
854			if (FreeBSD_Mflag && !stats_printed)
855				FreeBSD_stats_print(net_fd);
856			close(net_fd);
857			return;
858		}
859		/* listen and net in gone, queues empty, done */
860		if (lflag && pfd[POLL_NETIN].fd == -1
861		    && stdinbufpos == 0 && netinbufpos == 0) {
862			if (FreeBSD_Mflag && !stats_printed)
863				FreeBSD_stats_print(net_fd);
864			close(net_fd);
865			return;
866		}
867
868		/* help says -i is for "wait between lines sent". We read and
869		 * write arbitrary amounts of data, and we don't want to start
870		 * scanning for newlines, so this is as good as it gets */
871		if (iflag)
872			sleep(iflag);
873
874		/* poll */
875		num_fds = poll(pfd, 4, timeout);
876
877		/* treat poll errors */
878		if (num_fds == -1) {
879			close(net_fd);
880			err(1, "polling error");
881		}
882
883		/* timeout happened */
884		if (num_fds == 0) {
885			if (FreeBSD_Mflag)
886				FreeBSD_stats_print(net_fd);
887			return;
888		}
889
890		/* treat socket error conditions */
891		for (n = 0; n < 4; n++) {
892			if (pfd[n].revents & (POLLERR|POLLNVAL)) {
893				pfd[n].fd = -1;
894			}
895		}
896		/* reading is possible after HUP */
897		if (pfd[POLL_STDIN].events & POLLIN &&
898		    pfd[POLL_STDIN].revents & POLLHUP &&
899		    ! (pfd[POLL_STDIN].revents & POLLIN))
900				pfd[POLL_STDIN].fd = -1;
901
902		if (pfd[POLL_NETIN].events & POLLIN &&
903		    pfd[POLL_NETIN].revents & POLLHUP &&
904		    ! (pfd[POLL_NETIN].revents & POLLIN))
905				pfd[POLL_NETIN].fd = -1;
906
907		if (pfd[POLL_NETOUT].revents & POLLHUP) {
908			if (Nflag)
909				shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
910			pfd[POLL_NETOUT].fd = -1;
911		}
912		/* if HUP, stop watching stdout */
913		if (pfd[POLL_STDOUT].revents & POLLHUP)
914			pfd[POLL_STDOUT].fd = -1;
915		/* if no net out, stop watching stdin */
916		if (pfd[POLL_NETOUT].fd == -1)
917			pfd[POLL_STDIN].fd = -1;
918		/* if no stdout, stop watching net in */
919		if (pfd[POLL_STDOUT].fd == -1) {
920			if (pfd[POLL_NETIN].fd != -1)
921				shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
922			pfd[POLL_NETIN].fd = -1;
923		}
924
925		/* try to read from stdin */
926		if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) {
927			ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf,
928			    &stdinbufpos);
929			/* error or eof on stdin - remove from pfd */
930			if (ret == 0 || ret == -1)
931				pfd[POLL_STDIN].fd = -1;
932			/* read something - poll net out */
933			if (stdinbufpos > 0)
934				pfd[POLL_NETOUT].events = POLLOUT;
935			/* filled buffer - remove self from polling */
936			if (stdinbufpos == BUFSIZE)
937				pfd[POLL_STDIN].events = 0;
938		}
939		/* try to write to network */
940		if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) {
941			ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf,
942			    &stdinbufpos);
943			if (ret == -1)
944				pfd[POLL_NETOUT].fd = -1;
945			/* buffer empty - remove self from polling */
946			if (stdinbufpos == 0)
947				pfd[POLL_NETOUT].events = 0;
948			/* buffer no longer full - poll stdin again */
949			if (stdinbufpos < BUFSIZE)
950				pfd[POLL_STDIN].events = POLLIN;
951		}
952		/* try to read from network */
953		if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) {
954			ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf,
955			    &netinbufpos);
956			if (ret == -1)
957				pfd[POLL_NETIN].fd = -1;
958			/* eof on net in - remove from pfd */
959			if (ret == 0) {
960				shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
961				pfd[POLL_NETIN].fd = -1;
962			}
963			/* read something - poll stdout */
964			if (netinbufpos > 0)
965				pfd[POLL_STDOUT].events = POLLOUT;
966			/* filled buffer - remove self from polling */
967			if (netinbufpos == BUFSIZE)
968				pfd[POLL_NETIN].events = 0;
969			/* handle telnet */
970			if (tflag)
971				atelnet(pfd[POLL_NETIN].fd, netinbuf,
972				    netinbufpos);
973		}
974		/* try to write to stdout */
975		if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) {
976			ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf,
977			    &netinbufpos);
978			if (ret == -1)
979				pfd[POLL_STDOUT].fd = -1;
980			/* buffer empty - remove self from polling */
981			if (netinbufpos == 0)
982				pfd[POLL_STDOUT].events = 0;
983			/* buffer no longer full - poll net in again */
984			if (netinbufpos < BUFSIZE)
985				pfd[POLL_NETIN].events = POLLIN;
986		}
987
988		/* stdin gone and queue empty? */
989		if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) {
990			if (pfd[POLL_NETOUT].fd != -1 && Nflag) {
991				if (FreeBSD_Mflag) {
992					FreeBSD_stats_print(net_fd);
993					stats_printed = 1;
994				}
995				shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
996			}
997			pfd[POLL_NETOUT].fd = -1;
998		}
999		/* net in gone and queue empty? */
1000		if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) {
1001			pfd[POLL_STDOUT].fd = -1;
1002		}
1003	}
1004}
1005
1006ssize_t
1007drainbuf(int fd, unsigned char *buf, size_t *bufpos)
1008{
1009	ssize_t n;
1010	ssize_t adjust;
1011
1012	n = write(fd, buf, *bufpos);
1013	/* don't treat EAGAIN, EINTR as error */
1014	if (n == -1 && (errno == EAGAIN || errno == EINTR))
1015		n = -2;
1016	if (n <= 0)
1017		return n;
1018	/* adjust buffer */
1019	adjust = *bufpos - n;
1020	if (adjust > 0)
1021		memmove(buf, buf + n, adjust);
1022	*bufpos -= n;
1023	return n;
1024}
1025
1026
1027ssize_t
1028fillbuf(int fd, unsigned char *buf, size_t *bufpos)
1029{
1030	size_t num = BUFSIZE - *bufpos;
1031	ssize_t n;
1032
1033	n = read(fd, buf + *bufpos, num);
1034	/* don't treat EAGAIN, EINTR as error */
1035	if (n == -1 && (errno == EAGAIN || errno == EINTR))
1036		n = -2;
1037	if (n <= 0)
1038		return n;
1039	*bufpos += n;
1040	return n;
1041}
1042
1043/*
1044 * fdpass()
1045 * Pass the connected file descriptor to stdout and exit.
1046 */
1047void
1048fdpass(int nfd)
1049{
1050	struct msghdr mh;
1051	union {
1052		struct cmsghdr hdr;
1053		char buf[CMSG_SPACE(sizeof(int))];
1054	} cmsgbuf;
1055	struct cmsghdr *cmsg;
1056	struct iovec iov;
1057	char c = '\0';
1058	ssize_t r;
1059	struct pollfd pfd;
1060
1061	/* Avoid obvious stupidity */
1062	if (isatty(STDOUT_FILENO))
1063		errx(1, "Cannot pass file descriptor to tty");
1064
1065	bzero(&mh, sizeof(mh));
1066	bzero(&cmsgbuf, sizeof(cmsgbuf));
1067	bzero(&iov, sizeof(iov));
1068
1069	mh.msg_control = (caddr_t)&cmsgbuf.buf;
1070	mh.msg_controllen = sizeof(cmsgbuf.buf);
1071	cmsg = CMSG_FIRSTHDR(&mh);
1072	cmsg->cmsg_len = CMSG_LEN(sizeof(int));
1073	cmsg->cmsg_level = SOL_SOCKET;
1074	cmsg->cmsg_type = SCM_RIGHTS;
1075	*(int *)CMSG_DATA(cmsg) = nfd;
1076
1077	iov.iov_base = &c;
1078	iov.iov_len = 1;
1079	mh.msg_iov = &iov;
1080	mh.msg_iovlen = 1;
1081
1082	bzero(&pfd, sizeof(pfd));
1083	pfd.fd = STDOUT_FILENO;
1084	pfd.events = POLLOUT;
1085	for (;;) {
1086		r = sendmsg(STDOUT_FILENO, &mh, 0);
1087		if (r == -1) {
1088			if (errno == EAGAIN || errno == EINTR) {
1089				if (poll(&pfd, 1, -1) == -1)
1090					err(1, "poll");
1091				continue;
1092			}
1093			err(1, "sendmsg");
1094		} else if (r != 1)
1095			errx(1, "sendmsg: unexpected return value %zd", r);
1096		else
1097			break;
1098	}
1099	exit(0);
1100}
1101
1102/* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */
1103void
1104atelnet(int nfd, unsigned char *buf, unsigned int size)
1105{
1106	unsigned char *p, *end;
1107	unsigned char obuf[4];
1108
1109	if (size < 3)
1110		return;
1111	end = buf + size - 2;
1112
1113	for (p = buf; p < end; p++) {
1114		if (*p != IAC)
1115			continue;
1116
1117		obuf[0] = IAC;
1118		p++;
1119		if ((*p == WILL) || (*p == WONT))
1120			obuf[1] = DONT;
1121		else if ((*p == DO) || (*p == DONT))
1122			obuf[1] = WONT;
1123		else
1124			continue;
1125
1126		p++;
1127		obuf[2] = *p;
1128		if (atomicio(vwrite, nfd, obuf, 3) != 3)
1129			warn("Write Error!");
1130	}
1131}
1132
1133/*
1134 * build_ports()
1135 * Build an array of ports in portlist[], listing each port
1136 * that we should try to connect to.
1137 */
1138void
1139build_ports(char *p)
1140{
1141	const char *errstr;
1142	char *n;
1143	int hi, lo, cp;
1144	int x = 0;
1145
1146	if ((n = strchr(p, '-')) != NULL) {
1147		*n = '\0';
1148		n++;
1149
1150		/* Make sure the ports are in order: lowest->highest. */
1151		hi = strtonum(n, 1, PORT_MAX, &errstr);
1152		if (errstr)
1153			errx(1, "port number %s: %s", errstr, n);
1154		lo = strtonum(p, 1, PORT_MAX, &errstr);
1155		if (errstr)
1156			errx(1, "port number %s: %s", errstr, p);
1157
1158		if (lo > hi) {
1159			cp = hi;
1160			hi = lo;
1161			lo = cp;
1162		}
1163
1164		/* Load ports sequentially. */
1165		for (cp = lo; cp <= hi; cp++) {
1166			portlist[x] = calloc(1, PORT_MAX_LEN);
1167			if (portlist[x] == NULL)
1168				err(1, NULL);
1169			snprintf(portlist[x], PORT_MAX_LEN, "%d", cp);
1170			x++;
1171		}
1172
1173		/* Randomly swap ports. */
1174		if (rflag) {
1175			int y;
1176			char *c;
1177
1178			for (x = 0; x <= (hi - lo); x++) {
1179				y = (arc4random() & 0xFFFF) % (hi - lo);
1180				c = portlist[x];
1181				portlist[x] = portlist[y];
1182				portlist[y] = c;
1183			}
1184		}
1185	} else {
1186		hi = strtonum(p, 1, PORT_MAX, &errstr);
1187		if (errstr)
1188			errx(1, "port number %s: %s", errstr, p);
1189		portlist[0] = strdup(p);
1190		if (portlist[0] == NULL)
1191			err(1, NULL);
1192	}
1193}
1194
1195/*
1196 * udptest()
1197 * Do a few writes to see if the UDP port is there.
1198 * Fails once PF state table is full.
1199 */
1200int
1201udptest(int s)
1202{
1203	int i, ret;
1204
1205	for (i = 0; i <= 3; i++) {
1206		if (write(s, "X", 1) == 1)
1207			ret = 1;
1208		else
1209			ret = -1;
1210	}
1211	return (ret);
1212}
1213
1214void
1215FreeBSD_stats_setup(int s)
1216{
1217
1218	if (setsockopt(s, IPPROTO_TCP, TCP_STATS,
1219	    &FreeBSD_Mflag, sizeof(FreeBSD_Mflag)) == -1) {
1220		if (errno == EOPNOTSUPP) {
1221			warnx("getsockopt(TCP_STATS) failed; "
1222			    "kernel built without \"options STATS\"?");
1223		}
1224		err(1, "enable TCP_STATS gathering");
1225	}
1226}
1227
1228void
1229FreeBSD_stats_print(int s)
1230{
1231#ifdef WITH_STATS
1232	struct statsblob *statsb;
1233	struct sbuf *sb;
1234	socklen_t sockoptlen;
1235	int error;
1236
1237	/*
1238	 * This usleep is a workaround for TCP_STATS reporting
1239	 * incorrect values for TXPB.
1240	 */
1241	usleep(100000);
1242
1243	sockoptlen = 2048;
1244	statsb = malloc(sockoptlen);
1245	if (statsb == NULL)
1246		err(1, "malloc");
1247	error = getsockopt(s, IPPROTO_TCP, TCP_STATS, statsb, &sockoptlen);
1248	if (error != 0) {
1249		if (errno == EOVERFLOW && statsb->cursz > sockoptlen) {
1250			/* Retry with a larger size. */
1251			sockoptlen = statsb->cursz;
1252			statsb = realloc(statsb, sockoptlen);
1253			if (statsb == NULL)
1254				err(1, "realloc");
1255			error = getsockopt(s, IPPROTO_TCP, TCP_STATS,
1256			    statsb, &sockoptlen);
1257		}
1258		if (error != 0)
1259			err(1, "getsockopt");
1260	}
1261
1262	sb = sbuf_new_auto();
1263	error = stats_blob_tostr(statsb, sb, SB_STRFMT_JSON, SB_TOSTR_META);
1264	if (error != 0)
1265		errc(1, error, "stats_blob_tostr");
1266
1267	error = sbuf_finish(sb);
1268	if (error != 0)
1269		err(1, "sbuf_finish");
1270
1271	fprintf(stderr, "%s\n", sbuf_data(sb));
1272#endif
1273}
1274
1275void
1276set_common_sockopts(int s, int af)
1277{
1278	int x = 1;
1279
1280	if (Sflag) {
1281		if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
1282			&x, sizeof(x)) == -1)
1283			err(1, NULL);
1284	}
1285	if (Dflag) {
1286		if (setsockopt(s, SOL_SOCKET, SO_DEBUG,
1287			&x, sizeof(x)) == -1)
1288			err(1, NULL);
1289	}
1290	if (Tflag != -1) {
1291		int proto, option;
1292
1293		if (af == AF_INET6) {
1294			proto = IPPROTO_IPV6;
1295			option = IPV6_TCLASS;
1296		} else {
1297			proto = IPPROTO_IP;
1298			option = IP_TOS;
1299		}
1300
1301		if (setsockopt(s, proto, option, &Tflag, sizeof(Tflag)) == -1)
1302			err(1, "set IP ToS");
1303	}
1304	if (Iflag) {
1305		if (setsockopt(s, SOL_SOCKET, SO_RCVBUF,
1306		    &Iflag, sizeof(Iflag)) == -1)
1307			err(1, "set TCP receive buffer size");
1308	}
1309	if (Oflag) {
1310		if (setsockopt(s, SOL_SOCKET, SO_SNDBUF,
1311		    &Oflag, sizeof(Oflag)) == -1)
1312			err(1, "set TCP send buffer size");
1313	}
1314	if (FreeBSD_Oflag) {
1315		if (setsockopt(s, IPPROTO_TCP, TCP_NOOPT,
1316		    &FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1)
1317			err(1, "disable TCP options");
1318	}
1319	if (FreeBSD_Mflag)
1320		FreeBSD_stats_setup(s);
1321#ifdef IPSEC
1322	if (ipsec_policy[0] != NULL)
1323		add_ipsec_policy(s, af, ipsec_policy[0]);
1324	if (ipsec_policy[1] != NULL)
1325		add_ipsec_policy(s, af, ipsec_policy[1]);
1326#endif
1327}
1328
1329int
1330map_tos(char *s, int *val)
1331{
1332	/* DiffServ Codepoints and other TOS mappings */
1333	const struct toskeywords {
1334		const char	*keyword;
1335		int		 val;
1336	} *t, toskeywords[] = {
1337		{ "af11",		IPTOS_DSCP_AF11 },
1338		{ "af12",		IPTOS_DSCP_AF12 },
1339		{ "af13",		IPTOS_DSCP_AF13 },
1340		{ "af21",		IPTOS_DSCP_AF21 },
1341		{ "af22",		IPTOS_DSCP_AF22 },
1342		{ "af23",		IPTOS_DSCP_AF23 },
1343		{ "af31",		IPTOS_DSCP_AF31 },
1344		{ "af32",		IPTOS_DSCP_AF32 },
1345		{ "af33",		IPTOS_DSCP_AF33 },
1346		{ "af41",		IPTOS_DSCP_AF41 },
1347		{ "af42",		IPTOS_DSCP_AF42 },
1348		{ "af43",		IPTOS_DSCP_AF43 },
1349		{ "critical",		IPTOS_PREC_CRITIC_ECP },
1350		{ "cs0",		IPTOS_DSCP_CS0 },
1351		{ "cs1",		IPTOS_DSCP_CS1 },
1352		{ "cs2",		IPTOS_DSCP_CS2 },
1353		{ "cs3",		IPTOS_DSCP_CS3 },
1354		{ "cs4",		IPTOS_DSCP_CS4 },
1355		{ "cs5",		IPTOS_DSCP_CS5 },
1356		{ "cs6",		IPTOS_DSCP_CS6 },
1357		{ "cs7",		IPTOS_DSCP_CS7 },
1358		{ "ef",			IPTOS_DSCP_EF },
1359		{ "inetcontrol",	IPTOS_PREC_INTERNETCONTROL },
1360		{ "lowdelay",		IPTOS_LOWDELAY },
1361		{ "netcontrol",		IPTOS_PREC_NETCONTROL },
1362		{ "reliability",	IPTOS_RELIABILITY },
1363		{ "throughput",		IPTOS_THROUGHPUT },
1364		{ NULL, 		-1 },
1365	};
1366
1367	for (t = toskeywords; t->keyword != NULL; t++) {
1368		if (strcmp(s, t->keyword) == 0) {
1369			*val = t->val;
1370			return (1);
1371		}
1372	}
1373
1374	return (0);
1375}
1376
1377void
1378report_connect(const struct sockaddr *sa, socklen_t salen)
1379{
1380	char remote_host[NI_MAXHOST];
1381	char remote_port[NI_MAXSERV];
1382	int herr;
1383	int flags = NI_NUMERICSERV;
1384
1385	if (nflag)
1386		flags |= NI_NUMERICHOST;
1387
1388	if ((herr = getnameinfo(sa, salen,
1389	    remote_host, sizeof(remote_host),
1390	    remote_port, sizeof(remote_port),
1391	    flags)) != 0) {
1392		if (herr == EAI_SYSTEM)
1393			err(1, "getnameinfo");
1394		else
1395			errx(1, "getnameinfo: %s", gai_strerror(herr));
1396	}
1397
1398	fprintf(stderr,
1399	    "Connection from %s %s "
1400	    "received!\n", remote_host, remote_port);
1401}
1402
1403void
1404help(void)
1405{
1406	usage(0);
1407	fprintf(stderr, "\tCommand Summary:\n\
1408	\t-4		Use IPv4\n\
1409	\t-6		Use IPv6\n\
1410	\t-D		Enable the debug socket option\n\
1411	\t-d		Detach from stdin\n");
1412#ifdef IPSEC
1413	fprintf(stderr, "\
1414	\t-E		Use IPsec ESP\n\
1415	\t-e policy	Use specified IPsec policy\n");
1416#endif
1417	fprintf(stderr, "\
1418	\t-F		Pass socket fd\n\
1419	\t-h		This help text\n\
1420	\t-I length	TCP receive buffer length\n\
1421	\t-i secs\t	Delay interval for lines sent, ports scanned\n\
1422	\t-k		Keep inbound sockets open for multiple connects\n\
1423	\t-l		Listen mode, for inbound connects\n\
1424	\t-N		Shutdown the network socket after EOF on stdin\n\
1425	\t-n		Suppress name/port resolutions\n\
1426	\t--no-tcpopt	Disable TCP options\n\
1427	\t-O length	TCP send buffer length\n\
1428	\t-P proxyuser\tUsername for proxy authentication\n\
1429	\t-p port\t	Specify local port for remote connects\n\
1430	\t-r		Randomize remote ports\n\
1431	\t-S		Enable the TCP MD5 signature option\n\
1432	\t-s addr\t	Local source address\n\
1433	\t-T toskeyword\tSet IP Type of Service\n\
1434	\t-t		Answer TELNET negotiation\n\
1435	\t-U		Use UNIX domain socket\n\
1436	\t-u		UDP mode\n\
1437	\t-V rtable	Specify alternate routing table\n\
1438	\t-v		Verbose\n\
1439	\t-w secs\t	Timeout for connects and final net reads\n\
1440	\t-X proto	Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\
1441	\t-x addr[:port]\tSpecify proxy address and port\n\
1442	\t-z		Zero-I/O mode [used for scanning]\n\
1443	Port numbers can be individual or ranges: lo-hi [inclusive]\n");
1444#ifdef IPSEC
1445	fprintf(stderr, "See ipsec_set_policy(3) for -e argument format\n");
1446#endif
1447	exit(1);
1448}
1449
1450#ifdef IPSEC
1451void
1452add_ipsec_policy(int s, int af, char *policy)
1453{
1454	char *raw;
1455	int e;
1456
1457	raw = ipsec_set_policy(policy, strlen(policy));
1458	if (raw == NULL)
1459		errx(1, "ipsec_set_policy `%s': %s", policy,
1460		     ipsec_strerror());
1461	if (af == AF_INET)
1462		e = setsockopt(s, IPPROTO_IP, IP_IPSEC_POLICY, raw,
1463		    ipsec_get_policylen(raw));
1464	if (af == AF_INET6)
1465		e = setsockopt(s, IPPROTO_IPV6, IPV6_IPSEC_POLICY, raw,
1466		    ipsec_get_policylen(raw));
1467	if (e < 0)
1468		err(1, "ipsec policy cannot be configured");
1469	free(raw);
1470	if (vflag)
1471		fprintf(stderr, "ipsec policy configured: `%s'\n", policy);
1472	return;
1473}
1474#endif /* IPSEC */
1475
1476void
1477usage(int ret)
1478{
1479	fprintf(stderr,
1480#ifdef IPSEC
1481	    "usage: nc [-46DdEFhklNnrStUuvz] [-e policy] [-I length] [-i interval] [-O length]\n"
1482#else
1483	    "usage: nc [-46DdFhklNnrStUuvz] [-I length] [-i interval] [-O length]\n"
1484#endif
1485	    "\t  [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n"
1486	    "\t  [-V rtable] [-w timeout] [-X proxy_protocol]\n"
1487	    "\t  [-x proxy_address[:port]] [destination] [port]\n");
1488	if (ret)
1489		exit(1);
1490}
1491