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 */
87 int dflag; /* detached, no stdin */
88 int Fflag; /* fdpass sock to stdout */
89 unsigned int iflag; /* Interval Flag */
90 int kflag; /* More than one connect */
91 int lflag; /* Bind to local port */
92 int FreeBSD_lb; /* Use SO_REUSEPORT_LB */
93 int FreeBSD_Mflag; /* Measure using stats(3) */
94 int Nflag; /* shutdown() network socket */
95 int nflag; /* Don't do name look up */
96 int FreeBSD_Oflag; /* Do not use TCP options */
97 int FreeBSD_sctp; /* Use SCTP */
98 int FreeBSD_crlf; /* Convert LF to CRLF */
99 char *Pflag; /* Proxy username */
100 char *pflag; /* Localport flag */
101 int rflag; /* Random ports flag */
102 char *sflag; /* Source Address */
103 int tflag; /* Telnet Emulation */
104 int uflag; /* UDP - Default to TCP */
105 int vflag; /* Verbosity */
106 int xflag; /* Socks proxy */
107 int zflag; /* Port Scan Flag */
108 int Dflag; /* sodebug */
109 int Iflag; /* TCP receive buffer size */
110 int Oflag; /* TCP send buffer size */
111 int Sflag; /* TCP MD5 signature option */
112 int Tflag = -1; /* IP Type of Service */
113 int rtableid = -1;
114
115 int timeout = -1;
116 int family = AF_UNSPEC;
117 int tun_fd = -1;
118 char *portlist[PORT_MAX+1];
119 char *unix_dg_tmp_socket;
120
121 void atelnet(int, unsigned char *, unsigned int);
122 int strtoport(char *portstr, int udp);
123 void build_ports(char *);
124 void help(void);
125 int local_listen(char *, char *, struct addrinfo);
126 void readwrite(int);
127 void fdpass(int nfd) __attribute__((noreturn));
128 int remote_connect(const char *, const char *, struct addrinfo);
129 int timeout_connect(int, const struct sockaddr *, socklen_t);
130 int socks_connect(const char *, const char *, struct addrinfo,
131 const char *, const char *, struct addrinfo, int, const char *);
132 int udptest(int);
133 int unix_bind(char *);
134 int unix_connect(char *);
135 int unix_listen(char *);
136 void FreeBSD_stats_setup(int);
137 void FreeBSD_stats_print(int);
138 void set_common_sockopts(int, int);
139 int map_tos(char *, int *);
140 void report_connect(const struct sockaddr *, socklen_t);
141 void usage(int);
142 ssize_t write_wrapper(int, const void *, size_t);
143 ssize_t drainbuf(int, unsigned char *, size_t *, int);
144 ssize_t fillbuf(int, unsigned char *, size_t *);
145
146 #ifdef IPSEC
147 void add_ipsec_policy(int, int, char *);
148
149 char *ipsec_policy[2];
150 #endif
151
152 enum {
153 FREEBSD_TUN = CHAR_MAX, /* avoid collision with return values from getopt */
154 };
155
156 int
main(int argc,char * argv[])157 main(int argc, char *argv[])
158 {
159 int ch, s, ret, socksv, ipsec_count;
160 int numfibs;
161 size_t intsize = sizeof(int);
162 char *host, *uport;
163 struct addrinfo hints;
164 struct servent *sv;
165 socklen_t len;
166 struct sockaddr_storage cliaddr;
167 char *proxy;
168 const char *errstr, *proxyhost = "", *proxyport = NULL, *tundev = NULL;
169 struct addrinfo proxyhints;
170 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE];
171 struct option longopts[] = {
172 { "crlf", no_argument, &FreeBSD_crlf, 1 },
173 { "lb", no_argument, &FreeBSD_lb, 1 },
174 { "no-tcpopt", no_argument, &FreeBSD_Oflag, 1 },
175 { "sctp", no_argument, &FreeBSD_sctp, 1 },
176 { "tun", required_argument, NULL, FREEBSD_TUN },
177 { NULL, 0, NULL, 0 }
178 };
179
180 ret = 1;
181 ipsec_count = 0;
182 s = 0;
183 socksv = 5;
184 host = NULL;
185 uport = NULL;
186 sv = NULL;
187
188 signal(SIGPIPE, SIG_IGN);
189
190 while ((ch = getopt_long(argc, argv,
191 "46DdEe:FhI:i:klMNnoO:P:p:rSs:tT:UuV:vw:X:x:z",
192 longopts, NULL)) != -1) {
193 switch (ch) {
194 case '4':
195 family = AF_INET;
196 break;
197 case '6':
198 family = AF_INET6;
199 break;
200 case 'U':
201 family = AF_UNIX;
202 break;
203 case 'X':
204 if (strcasecmp(optarg, "connect") == 0)
205 socksv = -1; /* HTTP proxy CONNECT */
206 else if (strcmp(optarg, "4") == 0)
207 socksv = 4; /* SOCKS v.4 */
208 else if (strcmp(optarg, "5") == 0)
209 socksv = 5; /* SOCKS v.5 */
210 else
211 errx(1, "unsupported proxy protocol");
212 break;
213 case 'd':
214 dflag = 1;
215 break;
216 case 'e':
217 #ifdef IPSEC
218 ipsec_policy[ipsec_count++ % 2] = optarg;
219 #else
220 errx(1, "IPsec support unavailable.");
221 #endif
222 break;
223 case 'E':
224 #ifdef IPSEC
225 ipsec_policy[0] = "in ipsec esp/transport//require";
226 ipsec_policy[1] = "out ipsec esp/transport//require";
227 #else
228 errx(1, "IPsec support unavailable.");
229 #endif
230 break;
231 case 'F':
232 Fflag = 1;
233 break;
234 case 'h':
235 help();
236 break;
237 case 'i':
238 iflag = strtonum(optarg, 0, UINT_MAX, &errstr);
239 if (errstr)
240 errx(1, "interval %s: %s", errstr, optarg);
241 break;
242 case 'k':
243 kflag = 1;
244 break;
245 case 'l':
246 lflag = 1;
247 break;
248 case 'M':
249 #ifndef WITH_STATS
250 errx(1, "-M requires stats(3) support");
251 #else
252 FreeBSD_Mflag = 1;
253 #endif
254 break;
255 case 'N':
256 Nflag = 1;
257 break;
258 case 'n':
259 nflag = 1;
260 break;
261 case 'o':
262 fprintf(stderr, "option -o is deprecated.\n");
263 break;
264 case 'P':
265 Pflag = optarg;
266 break;
267 case 'p':
268 pflag = optarg;
269 break;
270 case 'r':
271 rflag = 1;
272 break;
273 case 's':
274 sflag = optarg;
275 break;
276 case 't':
277 tflag = 1;
278 break;
279 case 'u':
280 uflag = 1;
281 break;
282 case 'V':
283 if (sysctlbyname("net.fibs", &numfibs, &intsize, NULL, 0) == -1)
284 errx(1, "Multiple FIBS not supported");
285 rtableid = (int)strtonum(optarg, 0,
286 numfibs - 1, &errstr);
287 if (errstr)
288 errx(1, "rtable %s: %s", errstr, optarg);
289 break;
290 case 'v':
291 vflag = 1;
292 break;
293 case 'w':
294 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr);
295 if (errstr)
296 errx(1, "timeout %s: %s", errstr, optarg);
297 timeout *= 1000;
298 break;
299 case 'x':
300 xflag = 1;
301 if ((proxy = strdup(optarg)) == NULL)
302 err(1, NULL);
303 break;
304 case 'z':
305 zflag = 1;
306 break;
307 case 'D':
308 Dflag = 1;
309 break;
310 case 'I':
311 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr);
312 if (errstr != NULL)
313 errx(1, "TCP receive window %s: %s",
314 errstr, optarg);
315 break;
316 case 'O':
317 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr);
318 if (errstr != NULL) {
319 if (strcmp(errstr, "invalid") != 0)
320 errx(1, "TCP send window %s: %s",
321 errstr, optarg);
322 }
323 break;
324 case 'S':
325 Sflag = 1;
326 break;
327 case 'T':
328 errstr = NULL;
329 errno = 0;
330 if (map_tos(optarg, &Tflag))
331 break;
332 if (strlen(optarg) > 1 && optarg[0] == '0' &&
333 optarg[1] == 'x')
334 Tflag = (int)strtol(optarg, NULL, 16);
335 else
336 Tflag = (int)strtonum(optarg, 0, 255,
337 &errstr);
338 if (Tflag < 0 || Tflag > 255 || errstr || errno)
339 errx(1, "illegal tos value %s", optarg);
340 break;
341 case FREEBSD_TUN:
342 tundev = optarg;
343 break;
344 case 0:
345 /* Long option. */
346 break;
347 default:
348 usage(1);
349 }
350 }
351 argc -= optind;
352 argv += optind;
353
354 /* Cruft to make sure options are clean, and used properly. */
355 if (argv[0] && !argv[1] && family == AF_UNIX) {
356 host = argv[0];
357 uport = NULL;
358 } else if (argv[0] && !argv[1]) {
359 if (!lflag)
360 usage(1);
361 uport = argv[0];
362 host = NULL;
363 } else if (argv[0] && argv[1]) {
364 host = argv[0];
365 uport = argv[1];
366 } else
367 usage(1);
368
369 if (lflag && sflag)
370 errx(1, "cannot use -s and -l");
371 if (lflag && pflag)
372 errx(1, "cannot use -p and -l");
373 if (lflag && zflag)
374 errx(1, "cannot use -z and -l");
375 if (!lflag && kflag)
376 errx(1, "must use -l with -k");
377 if (!lflag && FreeBSD_lb)
378 errx(1, "must use -l with --lb");
379 if (FreeBSD_sctp) {
380 if (uflag)
381 errx(1, "cannot use -u and --sctp");
382 if (family == AF_UNIX)
383 errx(1, "cannot use -U and --sctp");
384 }
385 if (tundev != NULL) {
386 if (!uflag)
387 errx(1, "must use --tun with -u");
388 tun_fd = open(tundev, O_RDWR);
389 if (tun_fd == -1)
390 errx(1, "unable to open tun device %s", tundev);
391 }
392
393 /* Get name of temporary socket for unix datagram client */
394 if ((family == AF_UNIX) && uflag && !lflag) {
395 if (sflag) {
396 unix_dg_tmp_socket = sflag;
397 } else {
398 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX",
399 UNIX_DG_TMP_SOCKET_SIZE);
400 if (mktemp(unix_dg_tmp_socket_buf) == NULL)
401 err(1, "mktemp");
402 unix_dg_tmp_socket = unix_dg_tmp_socket_buf;
403 }
404 }
405
406 /* Initialize addrinfo structure. */
407 if (family != AF_UNIX) {
408 memset(&hints, 0, sizeof(struct addrinfo));
409 hints.ai_family = family;
410 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
411 hints.ai_protocol = uflag ? IPPROTO_UDP :
412 FreeBSD_sctp ? IPPROTO_SCTP : IPPROTO_TCP;
413 if (nflag)
414 hints.ai_flags |= AI_NUMERICHOST;
415 }
416
417 if (xflag) {
418 if (uflag)
419 errx(1, "no proxy support for UDP mode");
420
421 if (FreeBSD_sctp)
422 errx(1, "no proxy support for SCTP mode");
423
424 if (lflag)
425 errx(1, "no proxy support for listen");
426
427 if (family == AF_UNIX)
428 errx(1, "no proxy support for unix sockets");
429
430 /* XXX IPv6 transport to proxy would probably work */
431 if (family == AF_INET6)
432 errx(1, "no proxy support for IPv6");
433
434 if (sflag)
435 errx(1, "no proxy support for local source address");
436
437 proxyhost = strsep(&proxy, ":");
438 proxyport = proxy;
439
440 memset(&proxyhints, 0, sizeof(struct addrinfo));
441 proxyhints.ai_family = family;
442 proxyhints.ai_socktype = SOCK_STREAM;
443 proxyhints.ai_protocol = IPPROTO_TCP;
444 if (nflag)
445 proxyhints.ai_flags |= AI_NUMERICHOST;
446 }
447
448 if (lflag) {
449 int connfd;
450 ret = 0;
451
452 if (family == AF_UNIX) {
453 if (uflag)
454 s = unix_bind(host);
455 else
456 s = unix_listen(host);
457 }
458
459 /* Allow only one connection at a time, but stay alive. */
460 for (;;) {
461 if (family != AF_UNIX)
462 s = local_listen(host, uport, hints);
463 if (s < 0)
464 err(1, NULL);
465 /*
466 * For UDP and -k, don't connect the socket, let it
467 * receive datagrams from multiple socket pairs.
468 */
469 if (uflag && kflag)
470 readwrite(s);
471 /*
472 * For UDP and not -k, we will use recvfrom() initially
473 * to wait for a caller, then use the regular functions
474 * to talk to the caller.
475 */
476 else if (uflag && !kflag) {
477 int rv, plen;
478 char buf[16384];
479 struct sockaddr_storage z;
480
481 len = sizeof(z);
482 plen = 2048;
483 rv = recvfrom(s, buf, plen, MSG_PEEK,
484 (struct sockaddr *)&z, &len);
485 if (rv < 0)
486 err(1, "recvfrom");
487
488 rv = connect(s, (struct sockaddr *)&z, len);
489 if (rv < 0)
490 err(1, "connect");
491
492 if (vflag)
493 report_connect((struct sockaddr *)&z, len);
494
495 readwrite(s);
496 } else {
497 len = sizeof(cliaddr);
498 connfd = accept(s, (struct sockaddr *)&cliaddr,
499 &len);
500 if (connfd == -1) {
501 /* For now, all errnos are fatal */
502 err(1, "accept");
503 }
504 if (vflag)
505 report_connect((struct sockaddr *)&cliaddr, len);
506
507 if (FreeBSD_Mflag)
508 FreeBSD_stats_setup(connfd);
509 readwrite(connfd);
510 close(connfd);
511 }
512
513 if (family != AF_UNIX)
514 close(s);
515 else if (uflag) {
516 if (connect(s, NULL, 0) < 0)
517 err(1, "connect");
518 }
519
520 if (!kflag)
521 break;
522 }
523 } else if (family == AF_UNIX) {
524 ret = 0;
525
526 if ((s = unix_connect(host)) > 0 && !zflag) {
527 readwrite(s);
528 close(s);
529 } else
530 ret = 1;
531
532 if (uflag)
533 unlink(unix_dg_tmp_socket);
534 exit(ret);
535
536 } else {
537 int i = 0;
538
539 /* Construct the portlist[] array. */
540 build_ports(uport);
541
542 /* Cycle through portlist, connecting to each port. */
543 for (i = 0; portlist[i] != NULL; i++) {
544 if (s)
545 close(s);
546
547 if (xflag)
548 s = socks_connect(host, portlist[i], hints,
549 proxyhost, proxyport, proxyhints, socksv,
550 Pflag);
551 else
552 s = remote_connect(host, portlist[i], hints);
553
554 if (s < 0)
555 continue;
556
557 ret = 0;
558 if (vflag || zflag) {
559 /* For UDP, make sure we are connected. */
560 if (uflag) {
561 if (udptest(s) == -1) {
562 ret = 1;
563 continue;
564 }
565 }
566
567 /* Don't look up port if -n. */
568 if (nflag)
569 sv = NULL;
570 else {
571 sv = getservbyport(
572 ntohs(atoi(portlist[i])),
573 uflag ? "udp" : "tcp");
574 }
575
576 fprintf(stderr,
577 "Connection to %s %s port [%s/%s] "
578 "succeeded!\n", host, portlist[i],
579 uflag ? "udp" : "tcp",
580 sv ? sv->s_name : "*");
581 }
582 if (Fflag)
583 fdpass(s);
584 else if (!zflag)
585 readwrite(s);
586 }
587 }
588
589 if (s)
590 close(s);
591 if (tun_fd != -1)
592 close(tun_fd);
593
594 exit(ret);
595 }
596
597 /*
598 * unix_bind()
599 * Returns a unix socket bound to the given path
600 */
601 int
unix_bind(char * path)602 unix_bind(char *path)
603 {
604 struct sockaddr_un sun;
605 int s;
606
607 /* Create unix domain socket. */
608 if ((s = socket(AF_UNIX, uflag ? SOCK_DGRAM : SOCK_STREAM,
609 0)) < 0)
610 return (-1);
611
612 memset(&sun, 0, sizeof(struct sockaddr_un));
613 sun.sun_family = AF_UNIX;
614
615 if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
616 sizeof(sun.sun_path)) {
617 close(s);
618 errno = ENAMETOOLONG;
619 return (-1);
620 }
621
622 if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
623 close(s);
624 return (-1);
625 }
626 return (s);
627 }
628
629 /*
630 * unix_connect()
631 * Returns a socket connected to a local unix socket. Returns -1 on failure.
632 */
633 int
unix_connect(char * path)634 unix_connect(char *path)
635 {
636 struct sockaddr_un sun;
637 int s;
638
639 if (uflag) {
640 if ((s = unix_bind(unix_dg_tmp_socket)) < 0)
641 return (-1);
642 } else {
643 if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
644 return (-1);
645 }
646 (void)fcntl(s, F_SETFD, FD_CLOEXEC);
647
648 memset(&sun, 0, sizeof(struct sockaddr_un));
649 sun.sun_family = AF_UNIX;
650
651 if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
652 sizeof(sun.sun_path)) {
653 close(s);
654 errno = ENAMETOOLONG;
655 return (-1);
656 }
657 if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
658 close(s);
659 return (-1);
660 }
661 return (s);
662
663 }
664
665 /*
666 * unix_listen()
667 * Create a unix domain socket, and listen on it.
668 */
669 int
unix_listen(char * path)670 unix_listen(char *path)
671 {
672 int s;
673 if ((s = unix_bind(path)) < 0)
674 return (-1);
675
676 if (listen(s, 5) < 0) {
677 close(s);
678 return (-1);
679 }
680 return (s);
681 }
682
683 /*
684 * remote_connect()
685 * Returns a socket connected to a remote host. Properly binds to a local
686 * port or source address if needed. Returns -1 on failure.
687 */
688 int
remote_connect(const char * host,const char * port,struct addrinfo hints)689 remote_connect(const char *host, const char *port, struct addrinfo hints)
690 {
691 struct addrinfo *res, *res0;
692 int s, error, on = 1;
693
694 if ((error = getaddrinfo(host, port, &hints, &res)))
695 errx(1, "getaddrinfo: %s", gai_strerror(error));
696
697 res0 = res;
698 do {
699 if ((s = socket(res0->ai_family, res0->ai_socktype,
700 res0->ai_protocol)) < 0)
701 continue;
702
703 if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_SETFIB,
704 &rtableid, sizeof(rtableid)) == -1))
705 err(1, "setsockopt SO_SETFIB");
706
707 /* Bind to a local port or source address if specified. */
708 if (sflag || pflag) {
709 struct addrinfo ahints, *ares;
710
711 /* try IP_BINDANY, but don't insist */
712 setsockopt(s, IPPROTO_IP, IP_BINDANY, &on, sizeof(on));
713 memset(&ahints, 0, sizeof(struct addrinfo));
714 ahints.ai_family = res0->ai_family;
715 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
716 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
717 ahints.ai_flags = AI_PASSIVE;
718 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares)))
719 errx(1, "getaddrinfo: %s", gai_strerror(error));
720
721 if (bind(s, (struct sockaddr *)ares->ai_addr,
722 ares->ai_addrlen) < 0)
723 err(1, "bind failed");
724 freeaddrinfo(ares);
725 }
726
727 set_common_sockopts(s, res0->ai_family);
728
729 if (timeout_connect(s, res0->ai_addr, res0->ai_addrlen) == 0)
730 break;
731 else if (vflag)
732 warn("connect to %s port %s (%s) failed", host, port,
733 uflag ? "udp" : "tcp");
734
735 close(s);
736 s = -1;
737 } while ((res0 = res0->ai_next) != NULL);
738
739 freeaddrinfo(res);
740
741 return (s);
742 }
743
744 int
timeout_connect(int s,const struct sockaddr * name,socklen_t namelen)745 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen)
746 {
747 struct pollfd pfd;
748 socklen_t optlen;
749 int flags, optval;
750 int ret;
751
752 if (timeout != -1) {
753 flags = fcntl(s, F_GETFL, 0);
754 if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1)
755 err(1, "set non-blocking mode");
756 }
757
758 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) {
759 pfd.fd = s;
760 pfd.events = POLLOUT;
761 if ((ret = poll(&pfd, 1, timeout)) == 1) {
762 optlen = sizeof(optval);
763 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR,
764 &optval, &optlen)) == 0) {
765 errno = optval;
766 ret = optval == 0 ? 0 : -1;
767 }
768 } else if (ret == 0) {
769 errno = ETIMEDOUT;
770 ret = -1;
771 } else
772 err(1, "poll failed");
773 }
774
775 if (timeout != -1 && fcntl(s, F_SETFL, flags) == -1)
776 err(1, "restoring flags");
777
778 return (ret);
779 }
780
781 /*
782 * local_listen()
783 * Returns a socket listening on a local port, binds to specified source
784 * address. Returns -1 on failure.
785 */
786 int
local_listen(char * host,char * port,struct addrinfo hints)787 local_listen(char *host, char *port, struct addrinfo hints)
788 {
789 struct addrinfo *res, *res0;
790 int s, ret, x = 1;
791 int error;
792
793 /* Allow nodename to be null. */
794 hints.ai_flags |= AI_PASSIVE;
795
796 /*
797 * In the case of binding to a wildcard address
798 * default to binding to an ipv4 address.
799 */
800 if (host == NULL && hints.ai_family == AF_UNSPEC)
801 hints.ai_family = AF_INET;
802
803 if ((error = getaddrinfo(host, port, &hints, &res)))
804 errx(1, "getaddrinfo: %s", gai_strerror(error));
805
806 res0 = res;
807 do {
808 int opt;
809
810 if ((s = socket(res0->ai_family, res0->ai_socktype,
811 res0->ai_protocol)) < 0)
812 continue;
813
814 if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_SETFIB,
815 &rtableid, sizeof(rtableid)) == -1))
816 err(1, "setsockopt SO_SETFIB");
817
818 opt = FreeBSD_lb != 0 ? SO_REUSEPORT_LB : SO_REUSEPORT;
819 ret = setsockopt(s, SOL_SOCKET, opt, &x, sizeof(x));
820 if (ret == -1)
821 err(1, NULL);
822
823 if (FreeBSD_Oflag) {
824 if (setsockopt(s, IPPROTO_TCP, TCP_NOOPT,
825 &FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1)
826 err(1, "disable TCP options");
827 }
828
829 set_common_sockopts(s, res0->ai_family);
830
831 if (bind(s, (struct sockaddr *)res0->ai_addr,
832 res0->ai_addrlen) == 0)
833 break;
834
835 close(s);
836 s = -1;
837 } while ((res0 = res0->ai_next) != NULL);
838
839 if (!uflag && s != -1) {
840 if (listen(s, 1) < 0)
841 err(1, "listen");
842 }
843
844 freeaddrinfo(res);
845
846 return (s);
847 }
848
849 /*
850 * readwrite()
851 * Loop that polls on the network file descriptor and stdin.
852 */
853 void
readwrite(int net_fd)854 readwrite(int net_fd)
855 {
856 struct pollfd pfd[4];
857 int stdin_fd = STDIN_FILENO;
858 int stdout_fd = STDOUT_FILENO;
859 unsigned char netinbuf[BUFSIZE];
860 size_t netinbufpos = 0;
861 unsigned char stdinbuf[BUFSIZE];
862 size_t stdinbufpos = 0;
863 int n, num_fds;
864 int stats_printed = 0;
865 ssize_t ret;
866
867 /* don't read from stdin if requested */
868 if (dflag)
869 stdin_fd = -1;
870
871 /* stdin */
872 pfd[POLL_STDIN].fd = (tun_fd != -1) ? tun_fd : stdin_fd;
873 pfd[POLL_STDIN].events = POLLIN;
874
875 /* network out */
876 pfd[POLL_NETOUT].fd = net_fd;
877 pfd[POLL_NETOUT].events = 0;
878
879 /* network in */
880 pfd[POLL_NETIN].fd = net_fd;
881 pfd[POLL_NETIN].events = POLLIN;
882
883 /* stdout */
884 pfd[POLL_STDOUT].fd = (tun_fd != -1) ? tun_fd : stdout_fd;
885 pfd[POLL_STDOUT].events = 0;
886
887 while (1) {
888 /* both inputs are gone, buffers are empty, we are done */
889 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1
890 && stdinbufpos == 0 && netinbufpos == 0) {
891 if (FreeBSD_Mflag && !stats_printed)
892 FreeBSD_stats_print(net_fd);
893 close(net_fd);
894 return;
895 }
896 /* both outputs are gone, we can't continue */
897 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) {
898 if (FreeBSD_Mflag && !stats_printed)
899 FreeBSD_stats_print(net_fd);
900 close(net_fd);
901 return;
902 }
903 /* listen and net in gone, queues empty, done */
904 if (lflag && pfd[POLL_NETIN].fd == -1
905 && stdinbufpos == 0 && netinbufpos == 0) {
906 if (FreeBSD_Mflag && !stats_printed)
907 FreeBSD_stats_print(net_fd);
908 close(net_fd);
909 return;
910 }
911
912 /* help says -i is for "wait between lines sent". We read and
913 * write arbitrary amounts of data, and we don't want to start
914 * scanning for newlines, so this is as good as it gets */
915 if (iflag)
916 sleep(iflag);
917
918 /* poll */
919 num_fds = poll(pfd, 4, timeout);
920
921 /* treat poll errors */
922 if (num_fds == -1) {
923 close(net_fd);
924 err(1, "polling error");
925 }
926
927 /* timeout happened */
928 if (num_fds == 0) {
929 if (FreeBSD_Mflag)
930 FreeBSD_stats_print(net_fd);
931 return;
932 }
933
934 /* treat socket error conditions */
935 for (n = 0; n < 4; n++) {
936 if (pfd[n].revents & (POLLERR|POLLNVAL)) {
937 pfd[n].fd = -1;
938 }
939 }
940 /* reading is possible after HUP */
941 if (pfd[POLL_STDIN].events & POLLIN &&
942 pfd[POLL_STDIN].revents & POLLHUP &&
943 ! (pfd[POLL_STDIN].revents & POLLIN))
944 pfd[POLL_STDIN].fd = -1;
945
946 if (pfd[POLL_NETIN].events & POLLIN &&
947 pfd[POLL_NETIN].revents & POLLHUP &&
948 ! (pfd[POLL_NETIN].revents & POLLIN))
949 pfd[POLL_NETIN].fd = -1;
950
951 if (pfd[POLL_NETOUT].revents & POLLHUP) {
952 if (Nflag)
953 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
954 pfd[POLL_NETOUT].fd = -1;
955 }
956 /* if HUP, stop watching stdout */
957 if (pfd[POLL_STDOUT].revents & POLLHUP)
958 pfd[POLL_STDOUT].fd = -1;
959 /* if no net out, stop watching stdin */
960 if (pfd[POLL_NETOUT].fd == -1)
961 pfd[POLL_STDIN].fd = -1;
962 /* if no stdout, stop watching net in */
963 if (pfd[POLL_STDOUT].fd == -1) {
964 if (pfd[POLL_NETIN].fd != -1)
965 shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
966 pfd[POLL_NETIN].fd = -1;
967 }
968
969 /* try to read from stdin */
970 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) {
971 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf,
972 &stdinbufpos);
973 /* error or eof on stdin - remove from pfd */
974 if (ret == 0 || ret == -1)
975 pfd[POLL_STDIN].fd = -1;
976 /* read something - poll net out */
977 if (stdinbufpos > 0)
978 pfd[POLL_NETOUT].events = POLLOUT;
979 /* filled buffer - remove self from polling */
980 if (stdinbufpos == BUFSIZE)
981 pfd[POLL_STDIN].events = 0;
982 }
983 /* try to write to network */
984 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) {
985 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf,
986 &stdinbufpos, FreeBSD_crlf);
987 if (ret == -1)
988 pfd[POLL_NETOUT].fd = -1;
989 /* buffer empty - remove self from polling */
990 if (stdinbufpos == 0)
991 pfd[POLL_NETOUT].events = 0;
992 /* buffer no longer full - poll stdin again */
993 if (stdinbufpos < BUFSIZE)
994 pfd[POLL_STDIN].events = POLLIN;
995 }
996 /* try to read from network */
997 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) {
998 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf,
999 &netinbufpos);
1000 if (ret == -1)
1001 pfd[POLL_NETIN].fd = -1;
1002 /* eof on net in - remove from pfd */
1003 if (ret == 0) {
1004 shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
1005 pfd[POLL_NETIN].fd = -1;
1006 }
1007 /* read something - poll stdout */
1008 if (netinbufpos > 0)
1009 pfd[POLL_STDOUT].events = POLLOUT;
1010 /* filled buffer - remove self from polling */
1011 if (netinbufpos == BUFSIZE)
1012 pfd[POLL_NETIN].events = 0;
1013 /* handle telnet */
1014 if (tflag)
1015 atelnet(pfd[POLL_NETIN].fd, netinbuf,
1016 netinbufpos);
1017 }
1018 /* try to write to stdout */
1019 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) {
1020 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf,
1021 &netinbufpos, 0);
1022 if (ret == -1)
1023 pfd[POLL_STDOUT].fd = -1;
1024 /* buffer empty - remove self from polling */
1025 if (netinbufpos == 0)
1026 pfd[POLL_STDOUT].events = 0;
1027 /* buffer no longer full - poll net in again */
1028 if (netinbufpos < BUFSIZE)
1029 pfd[POLL_NETIN].events = POLLIN;
1030 }
1031
1032 /* stdin gone and queue empty? */
1033 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) {
1034 if (pfd[POLL_NETOUT].fd != -1 && Nflag) {
1035 if (FreeBSD_Mflag) {
1036 FreeBSD_stats_print(net_fd);
1037 stats_printed = 1;
1038 }
1039 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
1040 }
1041 pfd[POLL_NETOUT].fd = -1;
1042 }
1043 /* net in gone and queue empty? */
1044 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) {
1045 pfd[POLL_STDOUT].fd = -1;
1046 }
1047 }
1048 }
1049
1050 ssize_t
write_wrapper(int fd,const void * buf,size_t buflen)1051 write_wrapper(int fd, const void *buf, size_t buflen)
1052 {
1053 ssize_t n = write(fd, buf, buflen);
1054 /* don't treat EAGAIN, EINTR as error */
1055 return (n == -1 && (errno == EAGAIN || errno == EINTR)) ? -2 : n;
1056 }
1057
1058 ssize_t
drainbuf(int fd,unsigned char * buf,size_t * bufpos,int crlf)1059 drainbuf(int fd, unsigned char *buf, size_t *bufpos, int crlf)
1060 {
1061 ssize_t n = *bufpos, n2 = 0;
1062 ssize_t adjust;
1063 unsigned char *lf = NULL;
1064
1065 if (crlf) {
1066 lf = memchr(buf, '\n', *bufpos);
1067 if (lf && (lf == buf || *(lf - 1) != '\r'))
1068 n = lf - buf;
1069 else
1070 lf = NULL;
1071 }
1072
1073 if (n != 0) {
1074 n = write_wrapper(fd, buf, n);
1075 if (n <= 0)
1076 return n;
1077 }
1078
1079 if (lf) {
1080 n2 = write_wrapper(fd, "\r\n", 2);
1081 if (n2 <= 0)
1082 return n2;
1083 n += 1;
1084 }
1085
1086 /* adjust buffer */
1087 adjust = *bufpos - n;
1088 if (adjust > 0)
1089 memmove(buf, buf + n, adjust);
1090 *bufpos -= n;
1091 return n;
1092 }
1093
1094
1095 ssize_t
fillbuf(int fd,unsigned char * buf,size_t * bufpos)1096 fillbuf(int fd, unsigned char *buf, size_t *bufpos)
1097 {
1098 size_t num = BUFSIZE - *bufpos;
1099 ssize_t n;
1100
1101 n = read(fd, buf + *bufpos, num);
1102 /* don't treat EAGAIN, EINTR as error */
1103 if (n == -1 && (errno == EAGAIN || errno == EINTR))
1104 n = -2;
1105 if (n <= 0)
1106 return n;
1107 *bufpos += n;
1108 return n;
1109 }
1110
1111 /*
1112 * fdpass()
1113 * Pass the connected file descriptor to stdout and exit.
1114 */
1115 void
fdpass(int nfd)1116 fdpass(int nfd)
1117 {
1118 struct msghdr mh;
1119 union {
1120 struct cmsghdr hdr;
1121 char buf[CMSG_SPACE(sizeof(int))];
1122 } cmsgbuf;
1123 struct cmsghdr *cmsg;
1124 struct iovec iov;
1125 char c = '\0';
1126 ssize_t r;
1127 struct pollfd pfd;
1128
1129 /* Avoid obvious stupidity */
1130 if (isatty(STDOUT_FILENO))
1131 errx(1, "Cannot pass file descriptor to tty");
1132
1133 bzero(&mh, sizeof(mh));
1134 bzero(&cmsgbuf, sizeof(cmsgbuf));
1135 bzero(&iov, sizeof(iov));
1136
1137 mh.msg_control = (caddr_t)&cmsgbuf.buf;
1138 mh.msg_controllen = sizeof(cmsgbuf.buf);
1139 cmsg = CMSG_FIRSTHDR(&mh);
1140 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
1141 cmsg->cmsg_level = SOL_SOCKET;
1142 cmsg->cmsg_type = SCM_RIGHTS;
1143 *(int *)CMSG_DATA(cmsg) = nfd;
1144
1145 iov.iov_base = &c;
1146 iov.iov_len = 1;
1147 mh.msg_iov = &iov;
1148 mh.msg_iovlen = 1;
1149
1150 bzero(&pfd, sizeof(pfd));
1151 pfd.fd = STDOUT_FILENO;
1152 pfd.events = POLLOUT;
1153 for (;;) {
1154 r = sendmsg(STDOUT_FILENO, &mh, 0);
1155 if (r == -1) {
1156 if (errno == EAGAIN || errno == EINTR) {
1157 if (poll(&pfd, 1, -1) == -1)
1158 err(1, "poll");
1159 continue;
1160 }
1161 err(1, "sendmsg");
1162 } else if (r != 1)
1163 errx(1, "sendmsg: unexpected return value %zd", r);
1164 else
1165 break;
1166 }
1167 exit(0);
1168 }
1169
1170 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */
1171 void
atelnet(int nfd,unsigned char * buf,unsigned int size)1172 atelnet(int nfd, unsigned char *buf, unsigned int size)
1173 {
1174 unsigned char *p, *end;
1175 unsigned char obuf[4];
1176
1177 if (size < 3)
1178 return;
1179 end = buf + size - 2;
1180
1181 for (p = buf; p < end; p++) {
1182 if (*p != IAC)
1183 continue;
1184
1185 obuf[0] = IAC;
1186 p++;
1187 if ((*p == WILL) || (*p == WONT))
1188 obuf[1] = DONT;
1189 else if ((*p == DO) || (*p == DONT))
1190 obuf[1] = WONT;
1191 else
1192 continue;
1193
1194 p++;
1195 obuf[2] = *p;
1196 if (atomicio(vwrite, nfd, obuf, 3) != 3)
1197 warn("Write Error!");
1198 }
1199 }
1200
1201 int
strtoport(char * portstr,int udp)1202 strtoport(char *portstr, int udp)
1203 {
1204 struct servent *entry;
1205 const char *errstr;
1206 char *proto;
1207 int port = -1;
1208
1209 proto = udp ? "udp" : "tcp";
1210
1211 port = strtonum(portstr, 1, PORT_MAX, &errstr);
1212 if (errstr == NULL)
1213 return port;
1214 if (errno != EINVAL)
1215 errx(1, "port number %s: %s", errstr, portstr);
1216 if ((entry = getservbyname(portstr, proto)) == NULL)
1217 errx(1, "service \"%s\" unknown", portstr);
1218 return ntohs(entry->s_port);
1219 }
1220
1221 /*
1222 * build_ports()
1223 * Build an array of ports in portlist[], listing each port
1224 * that we should try to connect to.
1225 */
1226 void
build_ports(char * p)1227 build_ports(char *p)
1228 {
1229 char *n;
1230 int hi, lo, cp;
1231 int x = 0;
1232
1233 if ((n = strchr(p, '-')) != NULL) {
1234 *n = '\0';
1235 n++;
1236
1237 /* Make sure the ports are in order: lowest->highest. */
1238 hi = strtoport(n, uflag);
1239 lo = strtoport(p, uflag);
1240 if (lo > hi) {
1241 cp = hi;
1242 hi = lo;
1243 lo = cp;
1244 }
1245
1246 /* Load ports sequentially. */
1247 for (cp = lo; cp <= hi; cp++) {
1248 portlist[x] = calloc(1, PORT_MAX_LEN);
1249 if (portlist[x] == NULL)
1250 err(1, NULL);
1251 snprintf(portlist[x], PORT_MAX_LEN, "%d", cp);
1252 x++;
1253 }
1254
1255 /* Randomly swap ports. */
1256 if (rflag) {
1257 int y;
1258 char *c;
1259
1260 for (x = 0; x <= (hi - lo); x++) {
1261 y = (arc4random() & 0xFFFF) % (hi - lo);
1262 c = portlist[x];
1263 portlist[x] = portlist[y];
1264 portlist[y] = c;
1265 }
1266 }
1267 } else {
1268 char *tmp;
1269
1270 hi = strtoport(p, uflag);
1271 if (asprintf(&tmp, "%d", hi) != -1)
1272 portlist[0] = tmp;
1273 else
1274 err(1, NULL);
1275 }
1276 }
1277
1278 /*
1279 * udptest()
1280 * Do a few writes to see if the UDP port is there.
1281 * Fails once PF state table is full.
1282 */
1283 int
udptest(int s)1284 udptest(int s)
1285 {
1286 int i, ret;
1287
1288 for (i = 0; i <= 3; i++) {
1289 if (write(s, "X", 1) == 1)
1290 ret = 1;
1291 else
1292 ret = -1;
1293 }
1294 return (ret);
1295 }
1296
1297 void
FreeBSD_stats_setup(int s)1298 FreeBSD_stats_setup(int s)
1299 {
1300
1301 if (setsockopt(s, IPPROTO_TCP, TCP_STATS,
1302 &FreeBSD_Mflag, sizeof(FreeBSD_Mflag)) == -1) {
1303 if (errno == EOPNOTSUPP) {
1304 warnx("getsockopt(TCP_STATS) failed; "
1305 "kernel built without \"options STATS\"?");
1306 }
1307 err(1, "enable TCP_STATS gathering");
1308 }
1309 }
1310
1311 void
FreeBSD_stats_print(int s)1312 FreeBSD_stats_print(int s)
1313 {
1314 #ifdef WITH_STATS
1315 struct statsblob *statsb;
1316 struct sbuf *sb;
1317 socklen_t sockoptlen;
1318 int error;
1319
1320 /*
1321 * This usleep is a workaround for TCP_STATS reporting
1322 * incorrect values for TXPB.
1323 */
1324 usleep(100000);
1325
1326 sockoptlen = 2048;
1327 statsb = malloc(sockoptlen);
1328 if (statsb == NULL)
1329 err(1, "malloc");
1330 error = getsockopt(s, IPPROTO_TCP, TCP_STATS, statsb, &sockoptlen);
1331 if (error != 0) {
1332 if (errno == EOVERFLOW && statsb->cursz > sockoptlen) {
1333 /* Retry with a larger size. */
1334 sockoptlen = statsb->cursz;
1335 statsb = realloc(statsb, sockoptlen);
1336 if (statsb == NULL)
1337 err(1, "realloc");
1338 error = getsockopt(s, IPPROTO_TCP, TCP_STATS,
1339 statsb, &sockoptlen);
1340 }
1341 if (error != 0)
1342 err(1, "getsockopt");
1343 }
1344
1345 sb = sbuf_new_auto();
1346 error = stats_blob_tostr(statsb, sb, SB_STRFMT_JSON, SB_TOSTR_META);
1347 if (error != 0)
1348 errc(1, error, "stats_blob_tostr");
1349
1350 error = sbuf_finish(sb);
1351 if (error != 0)
1352 err(1, "sbuf_finish");
1353
1354 fprintf(stderr, "%s\n", sbuf_data(sb));
1355 #endif
1356 }
1357
1358 void
set_common_sockopts(int s,int af)1359 set_common_sockopts(int s, int af)
1360 {
1361 int x = 1;
1362
1363 if (Sflag) {
1364 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
1365 &x, sizeof(x)) == -1)
1366 err(1, NULL);
1367 }
1368 if (Dflag) {
1369 if (setsockopt(s, SOL_SOCKET, SO_DEBUG,
1370 &x, sizeof(x)) == -1)
1371 err(1, NULL);
1372 }
1373 if (Tflag != -1) {
1374 int proto, option;
1375
1376 if (af == AF_INET6) {
1377 proto = IPPROTO_IPV6;
1378 option = IPV6_TCLASS;
1379 } else {
1380 proto = IPPROTO_IP;
1381 option = IP_TOS;
1382 }
1383
1384 if (setsockopt(s, proto, option, &Tflag, sizeof(Tflag)) == -1)
1385 err(1, "set IP ToS");
1386 }
1387 if (Iflag) {
1388 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF,
1389 &Iflag, sizeof(Iflag)) == -1)
1390 err(1, "set TCP receive buffer size");
1391 }
1392 if (Oflag) {
1393 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF,
1394 &Oflag, sizeof(Oflag)) == -1)
1395 err(1, "set TCP send buffer size");
1396 }
1397 if (FreeBSD_Oflag) {
1398 if (setsockopt(s, IPPROTO_TCP, TCP_NOOPT,
1399 &FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1)
1400 err(1, "disable TCP options");
1401 }
1402 if (FreeBSD_Mflag)
1403 FreeBSD_stats_setup(s);
1404 #ifdef IPSEC
1405 if (ipsec_policy[0] != NULL)
1406 add_ipsec_policy(s, af, ipsec_policy[0]);
1407 if (ipsec_policy[1] != NULL)
1408 add_ipsec_policy(s, af, ipsec_policy[1]);
1409 #endif
1410 }
1411
1412 int
map_tos(char * s,int * val)1413 map_tos(char *s, int *val)
1414 {
1415 /* DiffServ Codepoints and other TOS mappings */
1416 const struct toskeywords {
1417 const char *keyword;
1418 int val;
1419 } *t, toskeywords[] = {
1420 { "af11", IPTOS_DSCP_AF11 },
1421 { "af12", IPTOS_DSCP_AF12 },
1422 { "af13", IPTOS_DSCP_AF13 },
1423 { "af21", IPTOS_DSCP_AF21 },
1424 { "af22", IPTOS_DSCP_AF22 },
1425 { "af23", IPTOS_DSCP_AF23 },
1426 { "af31", IPTOS_DSCP_AF31 },
1427 { "af32", IPTOS_DSCP_AF32 },
1428 { "af33", IPTOS_DSCP_AF33 },
1429 { "af41", IPTOS_DSCP_AF41 },
1430 { "af42", IPTOS_DSCP_AF42 },
1431 { "af43", IPTOS_DSCP_AF43 },
1432 { "critical", IPTOS_PREC_CRITIC_ECP },
1433 { "cs0", IPTOS_DSCP_CS0 },
1434 { "cs1", IPTOS_DSCP_CS1 },
1435 { "cs2", IPTOS_DSCP_CS2 },
1436 { "cs3", IPTOS_DSCP_CS3 },
1437 { "cs4", IPTOS_DSCP_CS4 },
1438 { "cs5", IPTOS_DSCP_CS5 },
1439 { "cs6", IPTOS_DSCP_CS6 },
1440 { "cs7", IPTOS_DSCP_CS7 },
1441 { "ef", IPTOS_DSCP_EF },
1442 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL },
1443 { "lowdelay", IPTOS_LOWDELAY },
1444 { "netcontrol", IPTOS_PREC_NETCONTROL },
1445 { "reliability", IPTOS_RELIABILITY },
1446 { "throughput", IPTOS_THROUGHPUT },
1447 { NULL, -1 },
1448 };
1449
1450 for (t = toskeywords; t->keyword != NULL; t++) {
1451 if (strcmp(s, t->keyword) == 0) {
1452 *val = t->val;
1453 return (1);
1454 }
1455 }
1456
1457 return (0);
1458 }
1459
1460 void
report_connect(const struct sockaddr * sa,socklen_t salen)1461 report_connect(const struct sockaddr *sa, socklen_t salen)
1462 {
1463 char remote_host[NI_MAXHOST];
1464 char remote_port[NI_MAXSERV];
1465 int herr;
1466 int flags = NI_NUMERICSERV;
1467
1468 if (nflag)
1469 flags |= NI_NUMERICHOST;
1470
1471 if ((herr = getnameinfo(sa, salen,
1472 remote_host, sizeof(remote_host),
1473 remote_port, sizeof(remote_port),
1474 flags)) != 0) {
1475 if (herr == EAI_SYSTEM)
1476 err(1, "getnameinfo");
1477 else
1478 errx(1, "getnameinfo: %s", gai_strerror(herr));
1479 }
1480
1481 fprintf(stderr,
1482 "Connection from %s %s "
1483 "received!\n", remote_host, remote_port);
1484 }
1485
1486 void
help(void)1487 help(void)
1488 {
1489 usage(0);
1490 fprintf(stderr, "\tCommand Summary:\n\
1491 \t-4 Use IPv4\n\
1492 \t-6 Use IPv6\n\
1493 \t--crlf Convert LF into CRLF when sending data over the network\n\
1494 \t-D Enable the debug socket option\n\
1495 \t-d Detach from stdin\n");
1496 #ifdef IPSEC
1497 fprintf(stderr, "\
1498 \t-E Use IPsec ESP\n\
1499 \t-e policy Use specified IPsec policy\n");
1500 #endif
1501 fprintf(stderr, "\
1502 \t-F Pass socket fd\n\
1503 \t-h This help text\n\
1504 \t-I length TCP receive buffer length\n\
1505 \t-i secs\t Delay interval for lines sent, ports scanned\n\
1506 \t-k Keep inbound sockets open for multiple connects\n\
1507 \t-l Listen mode, for inbound connects\n\
1508 \t-N Shutdown the network socket after EOF on stdin\n\
1509 \t-n Suppress name/port resolutions\n\
1510 \t--no-tcpopt Disable TCP options\n\
1511 \t--sctp\t SCTP mode\n\
1512 \t--tun tundev Use tun device rather than stdio\n\
1513 \t-O length TCP send buffer length\n\
1514 \t-P proxyuser\tUsername for proxy authentication\n\
1515 \t-p port\t Specify local port for remote connects\n\
1516 \t-r Randomize remote ports\n\
1517 \t-S Enable the TCP MD5 signature option\n\
1518 \t-s addr\t Local source address\n\
1519 \t-T toskeyword\tSet IP Type of Service\n\
1520 \t-t Answer TELNET negotiation\n\
1521 \t-U Use UNIX domain socket\n\
1522 \t-u UDP mode\n\
1523 \t-V rtable Specify alternate routing table\n\
1524 \t-v Verbose\n\
1525 \t-w secs\t Timeout for connects and final net reads\n\
1526 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\
1527 \t-x addr[:port]\tSpecify proxy address and port\n\
1528 \t-z Zero-I/O mode [used for scanning]\n\
1529 Port numbers can be individual or ranges: lo-hi [inclusive]\n");
1530 #ifdef IPSEC
1531 fprintf(stderr, "\tSee ipsec_set_policy(3) for -e argument format\n");
1532 #endif
1533 exit(1);
1534 }
1535
1536 #ifdef IPSEC
1537 void
add_ipsec_policy(int s,int af,char * policy)1538 add_ipsec_policy(int s, int af, char *policy)
1539 {
1540 char *raw;
1541 int e;
1542
1543 raw = ipsec_set_policy(policy, strlen(policy));
1544 if (raw == NULL)
1545 errx(1, "ipsec_set_policy `%s': %s", policy,
1546 ipsec_strerror());
1547 if (af == AF_INET)
1548 e = setsockopt(s, IPPROTO_IP, IP_IPSEC_POLICY, raw,
1549 ipsec_get_policylen(raw));
1550 if (af == AF_INET6)
1551 e = setsockopt(s, IPPROTO_IPV6, IPV6_IPSEC_POLICY, raw,
1552 ipsec_get_policylen(raw));
1553 if (e < 0)
1554 err(1, "ipsec policy cannot be configured");
1555 free(raw);
1556 if (vflag)
1557 fprintf(stderr, "ipsec policy configured: `%s'\n", policy);
1558 return;
1559 }
1560 #endif /* IPSEC */
1561
1562 void
usage(int ret)1563 usage(int ret)
1564 {
1565 fprintf(stderr,
1566 #ifdef IPSEC
1567 "usage: nc [-46DdEFhklNnrStUuvz] [-e policy] [-I length] [-i interval] [-O length]\n"
1568 #else
1569 "usage: nc [-46DdFhklNnrStUuvz] [-I length] [-i interval] [-O length]\n"
1570 #endif
1571 "\t [--no-tcpopt] [--sctp]\n"
1572 "\t [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n"
1573 "\t [--tun tundev] [-V rtable] [-w timeout] [-X proxy_protocol]\n"
1574 "\t [-x proxy_address[:port]] [destination] [port]\n");
1575 if (ret)
1576 exit(1);
1577 }
1578