Annotation of src/usr.bin/nc/netcat.c, Revision 1.108
1.108 ! haesbaer 1: /* $OpenBSD: netcat.c,v 1.107 2012/04/01 02:58:57 deraadt Exp $ */
1.21 ericj 2: /*
3: * Copyright (c) 2001 Eric Jackson <ericj@monkey.org>
1.7 deraadt 4: *
1.21 ericj 5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
1.7 deraadt 8: *
1.21 ericj 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.
1.7 deraadt 16: *
1.21 ericj 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: */
1.1 deraadt 28:
1.24 ericj 29: /*
30: * Re-written nc(1) for OpenBSD. Original implementation by
1.21 ericj 31: * *Hobbit* <hobbit@avian.org>.
32: */
1.1 deraadt 33:
1.7 deraadt 34: #include <sys/types.h>
1.21 ericj 35: #include <sys/socket.h>
1.7 deraadt 36: #include <sys/time.h>
1.42 ericj 37: #include <sys/un.h>
1.21 ericj 38:
1.7 deraadt 39: #include <netinet/in.h>
1.83 dtucker 40: #include <netinet/in_systm.h>
1.65 markus 41: #include <netinet/tcp.h>
1.83 dtucker 42: #include <netinet/ip.h>
1.21 ericj 43: #include <arpa/telnet.h>
1.29 smart 44:
1.11 ericj 45: #include <err.h>
1.7 deraadt 46: #include <errno.h>
1.21 ericj 47: #include <netdb.h>
48: #include <poll.h>
1.13 ericj 49: #include <stdarg.h>
1.21 ericj 50: #include <stdio.h>
1.1 deraadt 51: #include <stdlib.h>
1.21 ericj 52: #include <string.h>
1.5 art 53: #include <unistd.h>
1.42 ericj 54: #include <fcntl.h>
1.85 millert 55: #include <limits.h>
1.79 avsm 56: #include "atomicio.h"
1.51 vincent 57:
58: #ifndef SUN_LEN
59: #define SUN_LEN(su) \
60: (sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))
61: #endif
1.1 deraadt 62:
1.55 fgsch 63: #define PORT_MAX 65535
64: #define PORT_MAX_LEN 6
1.99 jeremy 65: #define UNIX_DG_TMP_SOCKET_SIZE 19
1.31 ericj 66:
1.21 ericj 67: /* Command Line Options */
1.68 tedu 68: int dflag; /* detached, no stdin */
1.88 ray 69: unsigned int iflag; /* Interval Flag */
1.21 ericj 70: int kflag; /* More than one connect */
71: int lflag; /* Bind to local port */
1.67 jmc 72: int nflag; /* Don't do name look up */
1.86 djm 73: char *Pflag; /* Proxy username */
1.21 ericj 74: char *pflag; /* Localport flag */
75: int rflag; /* Random ports flag */
76: char *sflag; /* Source Address */
77: int tflag; /* Telnet Emulation */
78: int uflag; /* UDP - Default to TCP */
79: int vflag; /* Verbosity */
1.34 jakob 80: int xflag; /* Socks proxy */
1.21 ericj 81: int zflag; /* Port Scan Flag */
1.73 markus 82: int Dflag; /* sodebug */
1.90 djm 83: int Iflag; /* TCP receive buffer size */
84: int Oflag; /* TCP send buffer size */
1.65 markus 85: int Sflag; /* TCP MD5 signature option */
1.83 dtucker 86: int Tflag = -1; /* IP Type of Service */
1.98 guenther 87: u_int rtableid;
1.21 ericj 88:
1.49 hugh 89: int timeout = -1;
1.21 ericj 90: int family = AF_UNSPEC;
1.63 miod 91: char *portlist[PORT_MAX+1];
1.99 jeremy 92: char *unix_dg_tmp_socket;
1.21 ericj 93:
1.40 millert 94: void atelnet(int, unsigned char *, unsigned int);
95: void build_ports(char *);
96: void help(void);
97: int local_listen(char *, char *, struct addrinfo);
98: void readwrite(int);
1.77 otto 99: int remote_connect(const char *, const char *, struct addrinfo);
1.103 fgsch 100: int timeout_connect(int, const struct sockaddr *, socklen_t);
1.86 djm 101: int socks_connect(const char *, const char *, struct addrinfo,
102: const char *, const char *, struct addrinfo, int, const char *);
1.40 millert 103: int udptest(int);
1.99 jeremy 104: int unix_bind(char *);
1.42 ericj 105: int unix_connect(char *);
106: int unix_listen(char *);
1.84 dtucker 107: void set_common_sockopts(int);
1.102 haesbaer 108: int map_tos(char *, int *);
1.108 ! haesbaer 109: void report_connect(const struct sockaddr *, socklen_t);
1.40 millert 110: void usage(int);
1.1 deraadt 111:
1.21 ericj 112: int
1.37 jakob 113: main(int argc, char *argv[])
1.21 ericj 114: {
1.46 markus 115: int ch, s, ret, socksv;
1.88 ray 116: char *host, *uport;
1.21 ericj 117: struct addrinfo hints;
1.29 smart 118: struct servent *sv;
1.21 ericj 119: socklen_t len;
1.76 hshoexer 120: struct sockaddr_storage cliaddr;
1.34 jakob 121: char *proxy;
1.88 ray 122: const char *errstr, *proxyhost = "", *proxyport = NULL;
1.34 jakob 123: struct addrinfo proxyhints;
1.99 jeremy 124: char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE];
1.11 ericj 125:
1.29 smart 126: ret = 1;
127: s = 0;
1.46 markus 128: socksv = 5;
1.29 smart 129: host = NULL;
130: uport = NULL;
131: sv = NULL;
132:
1.80 mcbride 133: while ((ch = getopt(argc, argv,
1.106 dlg 134: "46DdhI:i:klnO:P:p:rSs:tT:UuV:vw:X:x:z")) != -1) {
1.21 ericj 135: switch (ch) {
136: case '4':
137: family = AF_INET;
138: break;
139: case '6':
140: family = AF_INET6;
141: break;
1.42 ericj 142: case 'U':
143: family = AF_UNIX;
144: break;
1.46 markus 145: case 'X':
1.75 djm 146: if (strcasecmp(optarg, "connect") == 0)
147: socksv = -1; /* HTTP proxy CONNECT */
148: else if (strcmp(optarg, "4") == 0)
149: socksv = 4; /* SOCKS v.4 */
150: else if (strcmp(optarg, "5") == 0)
151: socksv = 5; /* SOCKS v.5 */
152: else
153: errx(1, "unsupported proxy protocol");
1.46 markus 154: break;
1.68 tedu 155: case 'd':
156: dflag = 1;
157: break;
1.21 ericj 158: case 'h':
159: help();
160: break;
161: case 'i':
1.88 ray 162: iflag = strtonum(optarg, 0, UINT_MAX, &errstr);
163: if (errstr)
164: errx(1, "interval %s: %s", errstr, optarg);
1.21 ericj 165: break;
166: case 'k':
167: kflag = 1;
168: break;
169: case 'l':
170: lflag = 1;
171: break;
172: case 'n':
173: nflag = 1;
174: break;
1.86 djm 175: case 'P':
176: Pflag = optarg;
177: break;
1.21 ericj 178: case 'p':
179: pflag = optarg;
180: break;
181: case 'r':
182: rflag = 1;
183: break;
184: case 's':
185: sflag = optarg;
186: break;
187: case 't':
188: tflag = 1;
189: break;
190: case 'u':
191: uflag = 1;
192: break;
1.93 claudio 193: case 'V':
1.98 guenther 194: rtableid = (unsigned int)strtonum(optarg, 0,
1.93 claudio 195: RT_TABLEID_MAX, &errstr);
196: if (errstr)
1.98 guenther 197: errx(1, "rtable %s: %s", errstr, optarg);
1.93 claudio 198: break;
1.21 ericj 199: case 'v':
200: vflag = 1;
201: break;
1.70 deraadt 202: case 'w':
1.88 ray 203: timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr);
204: if (errstr)
205: errx(1, "timeout %s: %s", errstr, optarg);
1.49 hugh 206: timeout *= 1000;
1.21 ericj 207: break;
1.34 jakob 208: case 'x':
209: xflag = 1;
1.64 deraadt 210: if ((proxy = strdup(optarg)) == NULL)
211: err(1, NULL);
1.34 jakob 212: break;
1.21 ericj 213: case 'z':
214: zflag = 1;
215: break;
1.73 markus 216: case 'D':
217: Dflag = 1;
218: break;
1.90 djm 219: case 'I':
220: Iflag = strtonum(optarg, 1, 65536 << 14, &errstr);
221: if (errstr != NULL)
222: errx(1, "TCP receive window %s: %s",
223: errstr, optarg);
224: break;
225: case 'O':
226: Oflag = strtonum(optarg, 1, 65536 << 14, &errstr);
227: if (errstr != NULL)
228: errx(1, "TCP send window %s: %s",
229: errstr, optarg);
230: break;
1.65 markus 231: case 'S':
232: Sflag = 1;
233: break;
1.83 dtucker 234: case 'T':
1.102 haesbaer 235: errstr = NULL;
236: errno = 0;
237: if (map_tos(optarg, &Tflag))
238: break;
239: if (strlen(optarg) > 1 && optarg[0] == '0' &&
240: optarg[1] == 'x')
241: Tflag = (int)strtol(optarg, NULL, 16);
242: else
243: Tflag = (int)strtonum(optarg, 0, 255,
244: &errstr);
245: if (Tflag < 0 || Tflag > 255 || errstr || errno)
246: errx(1, "illegal tos value %s", optarg);
1.83 dtucker 247: break;
1.21 ericj 248: default:
249: usage(1);
250: }
251: }
252: argc -= optind;
253: argv += optind;
1.11 ericj 254:
1.21 ericj 255: /* Cruft to make sure options are clean, and used properly. */
1.42 ericj 256: if (argv[0] && !argv[1] && family == AF_UNIX) {
257: host = argv[0];
258: uport = NULL;
259: } else if (argv[0] && !argv[1]) {
1.21 ericj 260: if (!lflag)
261: usage(1);
262: uport = argv[0];
263: host = NULL;
264: } else if (argv[0] && argv[1]) {
265: host = argv[0];
266: uport = argv[1];
267: } else
268: usage(1);
1.1 deraadt 269:
1.21 ericj 270: if (lflag && sflag)
271: errx(1, "cannot use -s and -l");
272: if (lflag && pflag)
273: errx(1, "cannot use -p and -l");
274: if (lflag && zflag)
1.32 ericj 275: errx(1, "cannot use -z and -l");
1.21 ericj 276: if (!lflag && kflag)
1.32 ericj 277: errx(1, "must use -l with -k");
1.21 ericj 278:
1.99 jeremy 279: /* Get name of temporary socket for unix datagram client */
280: if ((family == AF_UNIX) && uflag && !lflag) {
281: if (sflag) {
282: unix_dg_tmp_socket = sflag;
283: } else {
284: strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX",
285: UNIX_DG_TMP_SOCKET_SIZE);
286: if (mktemp(unix_dg_tmp_socket_buf) == NULL)
287: err(1, "mktemp");
288: unix_dg_tmp_socket = unix_dg_tmp_socket_buf;
289: }
290: }
291:
1.67 jmc 292: /* Initialize addrinfo structure. */
1.42 ericj 293: if (family != AF_UNIX) {
294: memset(&hints, 0, sizeof(struct addrinfo));
295: hints.ai_family = family;
296: hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
297: hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
298: if (nflag)
299: hints.ai_flags |= AI_NUMERICHOST;
300: }
1.1 deraadt 301:
1.34 jakob 302: if (xflag) {
303: if (uflag)
304: errx(1, "no proxy support for UDP mode");
305:
306: if (lflag)
307: errx(1, "no proxy support for listen");
308:
1.42 ericj 309: if (family == AF_UNIX)
310: errx(1, "no proxy support for unix sockets");
311:
1.34 jakob 312: /* XXX IPv6 transport to proxy would probably work */
313: if (family == AF_INET6)
314: errx(1, "no proxy support for IPv6");
315:
316: if (sflag)
317: errx(1, "no proxy support for local source address");
318:
319: proxyhost = strsep(&proxy, ":");
320: proxyport = proxy;
321:
322: memset(&proxyhints, 0, sizeof(struct addrinfo));
323: proxyhints.ai_family = family;
324: proxyhints.ai_socktype = SOCK_STREAM;
325: proxyhints.ai_protocol = IPPROTO_TCP;
326: if (nflag)
327: proxyhints.ai_flags |= AI_NUMERICHOST;
328: }
329:
1.21 ericj 330: if (lflag) {
331: int connfd;
1.27 ericj 332: ret = 0;
1.1 deraadt 333:
1.99 jeremy 334: if (family == AF_UNIX) {
335: if (uflag)
336: s = unix_bind(host);
337: else
338: s = unix_listen(host);
339: }
1.42 ericj 340:
1.67 jmc 341: /* Allow only one connection at a time, but stay alive. */
1.21 ericj 342: for (;;) {
1.42 ericj 343: if (family != AF_UNIX)
344: s = local_listen(host, uport, hints);
345: if (s < 0)
1.30 smart 346: err(1, NULL);
1.21 ericj 347: /*
348: * For UDP, we will use recvfrom() initially
349: * to wait for a caller, then use the regular
350: * functions to talk to the caller.
351: */
352: if (uflag) {
1.80 mcbride 353: int rv, plen;
1.97 nicm 354: char buf[16384];
1.21 ericj 355: struct sockaddr_storage z;
356:
357: len = sizeof(z);
1.106 dlg 358: plen = 2048;
1.80 mcbride 359: rv = recvfrom(s, buf, plen, MSG_PEEK,
1.37 jakob 360: (struct sockaddr *)&z, &len);
1.23 ericj 361: if (rv < 0)
1.57 stevesk 362: err(1, "recvfrom");
1.21 ericj 363:
1.37 jakob 364: rv = connect(s, (struct sockaddr *)&z, len);
1.23 ericj 365: if (rv < 0)
1.57 stevesk 366: err(1, "connect");
1.1 deraadt 367:
1.108 ! haesbaer 368: if (vflag)
! 369: report_connect((struct sockaddr *)&z, len);
! 370:
1.99 jeremy 371: readwrite(s);
1.21 ericj 372: } else {
1.78 otto 373: len = sizeof(cliaddr);
1.21 ericj 374: connfd = accept(s, (struct sockaddr *)&cliaddr,
1.37 jakob 375: &len);
1.107 deraadt 376: if (connfd == -1)
377: err(1, "accept");
1.108 ! haesbaer 378:
! 379: if (vflag)
! 380: report_connect((struct sockaddr *)&cliaddr, len);
! 381:
1.99 jeremy 382: readwrite(connfd);
383: close(connfd);
1.21 ericj 384: }
1.1 deraadt 385:
1.42 ericj 386: if (family != AF_UNIX)
387: close(s);
1.99 jeremy 388: else if (uflag) {
389: if (connect(s, NULL, 0) < 0)
390: err(1, "connect");
391: }
1.27 ericj 392:
1.21 ericj 393: if (!kflag)
394: break;
1.11 ericj 395: }
1.42 ericj 396: } else if (family == AF_UNIX) {
397: ret = 0;
398:
399: if ((s = unix_connect(host)) > 0 && !zflag) {
400: readwrite(s);
401: close(s);
402: } else
403: ret = 1;
404:
1.99 jeremy 405: if (uflag)
406: unlink(unix_dg_tmp_socket);
1.42 ericj 407: exit(ret);
408:
1.21 ericj 409: } else {
410: int i = 0;
1.6 deraadt 411:
1.67 jmc 412: /* Construct the portlist[] array. */
1.21 ericj 413: build_ports(uport);
1.1 deraadt 414:
1.67 jmc 415: /* Cycle through portlist, connecting to each port. */
1.21 ericj 416: for (i = 0; portlist[i] != NULL; i++) {
417: if (s)
418: close(s);
1.34 jakob 419:
420: if (xflag)
421: s = socks_connect(host, portlist[i], hints,
1.86 djm 422: proxyhost, proxyport, proxyhints, socksv,
423: Pflag);
1.34 jakob 424: else
425: s = remote_connect(host, portlist[i], hints);
426:
427: if (s < 0)
1.21 ericj 428: continue;
1.1 deraadt 429:
1.21 ericj 430: ret = 0;
431: if (vflag || zflag) {
1.67 jmc 432: /* For UDP, make sure we are connected. */
1.21 ericj 433: if (uflag) {
1.50 vincent 434: if (udptest(s) == -1) {
1.21 ericj 435: ret = 1;
436: continue;
437: }
438: }
1.1 deraadt 439:
1.67 jmc 440: /* Don't look up port if -n. */
1.21 ericj 441: if (nflag)
442: sv = NULL;
443: else {
444: sv = getservbyport(
1.37 jakob 445: ntohs(atoi(portlist[i])),
446: uflag ? "udp" : "tcp");
1.21 ericj 447: }
1.50 vincent 448:
1.94 mpf 449: fprintf(stderr,
450: "Connection to %s %s port [%s/%s] "
451: "succeeded!\n", host, portlist[i],
452: uflag ? "udp" : "tcp",
1.37 jakob 453: sv ? sv->s_name : "*");
1.21 ericj 454: }
455: if (!zflag)
456: readwrite(s);
1.7 deraadt 457: }
1.11 ericj 458: }
1.1 deraadt 459:
1.21 ericj 460: if (s)
461: close(s);
462:
463: exit(ret);
1.7 deraadt 464: }
1.1 deraadt 465:
1.11 ericj 466: /*
1.99 jeremy 467: * unix_bind()
468: * Returns a unix socket bound to the given path
1.42 ericj 469: */
470: int
1.99 jeremy 471: unix_bind(char *path)
1.42 ericj 472: {
473: struct sockaddr_un sun;
474: int s;
475:
1.99 jeremy 476: /* Create unix domain socket. */
477: if ((s = socket(AF_UNIX, uflag ? SOCK_DGRAM : SOCK_STREAM,
478: 0)) < 0)
1.50 vincent 479: return (-1);
1.42 ericj 480:
481: memset(&sun, 0, sizeof(struct sockaddr_un));
482: sun.sun_family = AF_UNIX;
1.60 avsm 483:
484: if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
485: sizeof(sun.sun_path)) {
486: close(s);
487: errno = ENAMETOOLONG;
488: return (-1);
489: }
1.99 jeremy 490:
491: if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
1.50 vincent 492: close(s);
493: return (-1);
1.42 ericj 494: }
495: return (s);
496: }
497:
498: /*
1.99 jeremy 499: * unix_connect()
500: * Returns a socket connected to a local unix socket. Returns -1 on failure.
1.42 ericj 501: */
502: int
1.99 jeremy 503: unix_connect(char *path)
1.42 ericj 504: {
505: struct sockaddr_un sun;
506: int s;
507:
1.99 jeremy 508: if (uflag) {
509: if ((s = unix_bind(unix_dg_tmp_socket)) < 0)
510: return (-1);
511: } else {
512: if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
513: return (-1);
514: }
515: (void)fcntl(s, F_SETFD, 1);
1.42 ericj 516:
1.60 avsm 517: memset(&sun, 0, sizeof(struct sockaddr_un));
1.42 ericj 518: sun.sun_family = AF_UNIX;
1.60 avsm 519:
520: if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
521: sizeof(sun.sun_path)) {
522: close(s);
523: errno = ENAMETOOLONG;
524: return (-1);
525: }
1.99 jeremy 526: if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
1.42 ericj 527: close(s);
528: return (-1);
529: }
1.99 jeremy 530: return (s);
531:
532: }
533:
534: /*
535: * unix_listen()
536: * Create a unix domain socket, and listen on it.
537: */
538: int
539: unix_listen(char *path)
540: {
541: int s;
542: if ((s = unix_bind(path)) < 0)
543: return (-1);
1.42 ericj 544:
545: if (listen(s, 5) < 0) {
546: close(s);
547: return (-1);
548: }
549: return (s);
550: }
551:
552: /*
1.21 ericj 553: * remote_connect()
1.67 jmc 554: * Returns a socket connected to a remote host. Properly binds to a local
555: * port or source address if needed. Returns -1 on failure.
1.11 ericj 556: */
1.21 ericj 557: int
1.77 otto 558: remote_connect(const char *host, const char *port, struct addrinfo hints)
1.21 ericj 559: {
560: struct addrinfo *res, *res0;
1.91 markus 561: int s, error, on = 1;
1.21 ericj 562:
563: if ((error = getaddrinfo(host, port, &hints, &res)))
1.56 stevesk 564: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.21 ericj 565:
566: res0 = res;
567: do {
568: if ((s = socket(res0->ai_family, res0->ai_socktype,
1.37 jakob 569: res0->ai_protocol)) < 0)
1.21 ericj 570: continue;
571:
1.98 guenther 572: if (rtableid) {
1.101 mikeb 573: if (setsockopt(s, SOL_SOCKET, SO_RTABLE, &rtableid,
1.98 guenther 574: sizeof(rtableid)) == -1)
575: err(1, "setsockopt SO_RTABLE");
1.93 claudio 576: }
577:
1.67 jmc 578: /* Bind to a local port or source address if specified. */
1.21 ericj 579: if (sflag || pflag) {
580: struct addrinfo ahints, *ares;
1.6 deraadt 581:
1.91 markus 582: /* try SO_BINDANY, but don't insist */
583: setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on));
1.21 ericj 584: memset(&ahints, 0, sizeof(struct addrinfo));
585: ahints.ai_family = res0->ai_family;
586: ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
587: ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
1.25 ericj 588: ahints.ai_flags = AI_PASSIVE;
1.38 jakob 589: if ((error = getaddrinfo(sflag, pflag, &ahints, &ares)))
1.56 stevesk 590: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.21 ericj 591:
592: if (bind(s, (struct sockaddr *)ares->ai_addr,
1.62 millert 593: ares->ai_addrlen) < 0)
1.21 ericj 594: errx(1, "bind failed: %s", strerror(errno));
595: freeaddrinfo(ares);
1.6 deraadt 596: }
1.81 marius 597:
598: set_common_sockopts(s);
1.6 deraadt 599:
1.103 fgsch 600: if (timeout_connect(s, res0->ai_addr, res0->ai_addrlen) == 0)
1.6 deraadt 601: break;
1.71 mcbride 602: else if (vflag)
603: warn("connect to %s port %s (%s) failed", host, port,
604: uflag ? "udp" : "tcp");
1.34 jakob 605:
1.21 ericj 606: close(s);
607: s = -1;
608: } while ((res0 = res0->ai_next) != NULL);
609:
610: freeaddrinfo(res);
1.1 deraadt 611:
1.21 ericj 612: return (s);
1.103 fgsch 613: }
614:
615: int
616: timeout_connect(int s, const struct sockaddr *name, socklen_t namelen)
617: {
618: struct pollfd pfd;
619: socklen_t optlen;
620: int flags, optval;
621: int ret;
622:
623: if (timeout != -1) {
624: flags = fcntl(s, F_GETFL, 0);
625: if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1)
626: err(1, "set non-blocking mode");
627: }
628:
629: if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) {
630: pfd.fd = s;
631: pfd.events = POLLOUT;
632: if ((ret = poll(&pfd, 1, timeout)) == 1) {
633: optlen = sizeof(optval);
634: if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR,
635: &optval, &optlen)) == 0) {
636: errno = optval;
637: ret = optval == 0 ? 0 : -1;
638: }
639: } else if (ret == 0) {
640: errno = ETIMEDOUT;
641: ret = -1;
642: } else
643: err(1, "poll failed");
644: }
645:
646: if (timeout != -1 && fcntl(s, F_SETFL, flags) == -1)
647: err(1, "restoring flags");
648:
649: return (ret);
1.7 deraadt 650: }
1.1 deraadt 651:
1.11 ericj 652: /*
1.21 ericj 653: * local_listen()
1.67 jmc 654: * Returns a socket listening on a local port, binds to specified source
655: * address. Returns -1 on failure.
1.11 ericj 656: */
1.21 ericj 657: int
1.37 jakob 658: local_listen(char *host, char *port, struct addrinfo hints)
1.21 ericj 659: {
660: struct addrinfo *res, *res0;
661: int s, ret, x = 1;
662: int error;
1.6 deraadt 663:
1.67 jmc 664: /* Allow nodename to be null. */
1.21 ericj 665: hints.ai_flags |= AI_PASSIVE;
1.7 deraadt 666:
1.21 ericj 667: /*
668: * In the case of binding to a wildcard address
669: * default to binding to an ipv4 address.
670: */
671: if (host == NULL && hints.ai_family == AF_UNSPEC)
672: hints.ai_family = AF_INET;
1.1 deraadt 673:
1.21 ericj 674: if ((error = getaddrinfo(host, port, &hints, &res)))
1.70 deraadt 675: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.14 ericj 676:
1.21 ericj 677: res0 = res;
678: do {
679: if ((s = socket(res0->ai_family, res0->ai_socktype,
1.82 marius 680: res0->ai_protocol)) < 0)
1.21 ericj 681: continue;
1.1 deraadt 682:
1.98 guenther 683: if (rtableid) {
684: if (setsockopt(s, IPPROTO_IP, SO_RTABLE, &rtableid,
685: sizeof(rtableid)) == -1)
686: err(1, "setsockopt SO_RTABLE");
1.93 claudio 687: }
688:
1.21 ericj 689: ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x));
690: if (ret == -1)
1.30 smart 691: err(1, NULL);
1.81 marius 692:
693: set_common_sockopts(s);
1.1 deraadt 694:
1.21 ericj 695: if (bind(s, (struct sockaddr *)res0->ai_addr,
1.37 jakob 696: res0->ai_addrlen) == 0)
1.21 ericj 697: break;
1.1 deraadt 698:
1.21 ericj 699: close(s);
700: s = -1;
701: } while ((res0 = res0->ai_next) != NULL);
1.1 deraadt 702:
1.47 ericj 703: if (!uflag && s != -1) {
1.21 ericj 704: if (listen(s, 1) < 0)
1.57 stevesk 705: err(1, "listen");
1.12 ericj 706: }
1.1 deraadt 707:
1.21 ericj 708: freeaddrinfo(res);
1.1 deraadt 709:
1.21 ericj 710: return (s);
1.7 deraadt 711: }
712:
1.11 ericj 713: /*
1.21 ericj 714: * readwrite()
715: * Loop that polls on the network file descriptor and stdin.
1.11 ericj 716: */
1.21 ericj 717: void
1.37 jakob 718: readwrite(int nfd)
1.6 deraadt 719: {
1.52 vincent 720: struct pollfd pfd[2];
1.97 nicm 721: unsigned char buf[16384];
1.79 avsm 722: int n, wfd = fileno(stdin);
1.21 ericj 723: int lfd = fileno(stdout);
1.80 mcbride 724: int plen;
725:
1.106 dlg 726: plen = 2048;
1.21 ericj 727:
728: /* Setup Network FD */
729: pfd[0].fd = nfd;
730: pfd[0].events = POLLIN;
731:
1.67 jmc 732: /* Set up STDIN FD. */
1.21 ericj 733: pfd[1].fd = wfd;
734: pfd[1].events = POLLIN;
735:
1.54 aaron 736: while (pfd[0].fd != -1) {
1.21 ericj 737: if (iflag)
738: sleep(iflag);
739:
1.68 tedu 740: if ((n = poll(pfd, 2 - dflag, timeout)) < 0) {
1.21 ericj 741: close(nfd);
1.52 vincent 742: err(1, "Polling Error");
1.21 ericj 743: }
1.49 hugh 744:
745: if (n == 0)
746: return;
1.21 ericj 747:
748: if (pfd[0].revents & POLLIN) {
1.80 mcbride 749: if ((n = read(nfd, buf, plen)) < 0)
1.21 ericj 750: return;
1.52 vincent 751: else if (n == 0) {
752: shutdown(nfd, SHUT_RD);
753: pfd[0].fd = -1;
754: pfd[0].events = 0;
1.21 ericj 755: } else {
756: if (tflag)
757: atelnet(nfd, buf, n);
1.79 avsm 758: if (atomicio(vwrite, lfd, buf, n) != n)
1.21 ericj 759: return;
1.6 deraadt 760: }
1.21 ericj 761: }
762:
1.68 tedu 763: if (!dflag && pfd[1].revents & POLLIN) {
1.80 mcbride 764: if ((n = read(wfd, buf, plen)) < 0)
1.21 ericj 765: return;
1.52 vincent 766: else if (n == 0) {
767: shutdown(nfd, SHUT_WR);
768: pfd[1].fd = -1;
769: pfd[1].events = 0;
770: } else {
1.79 avsm 771: if (atomicio(vwrite, nfd, buf, n) != n)
1.21 ericj 772: return;
1.50 vincent 773: }
1.21 ericj 774: }
1.11 ericj 775: }
1.7 deraadt 776: }
1.50 vincent 777:
1.67 jmc 778: /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */
1.21 ericj 779: void
1.37 jakob 780: atelnet(int nfd, unsigned char *buf, unsigned int size)
1.6 deraadt 781: {
1.24 ericj 782: unsigned char *p, *end;
783: unsigned char obuf[4];
784:
1.95 nicm 785: if (size < 3)
786: return;
787: end = buf + size - 2;
1.24 ericj 788:
789: for (p = buf; p < end; p++) {
1.21 ericj 790: if (*p != IAC)
1.95 nicm 791: continue;
1.24 ericj 792:
1.25 ericj 793: obuf[0] = IAC;
1.24 ericj 794: p++;
1.50 vincent 795: if ((*p == WILL) || (*p == WONT))
1.24 ericj 796: obuf[1] = DONT;
1.95 nicm 797: else if ((*p == DO) || (*p == DONT))
1.24 ericj 798: obuf[1] = WONT;
1.95 nicm 799: else
800: continue;
801:
802: p++;
803: obuf[2] = *p;
804: if (atomicio(vwrite, nfd, obuf, 3) != 3)
805: warn("Write Error!");
1.11 ericj 806: }
1.7 deraadt 807: }
808:
1.11 ericj 809: /*
1.21 ericj 810: * build_ports()
1.105 lum 811: * Build an array of ports in portlist[], listing each port
1.67 jmc 812: * that we should try to connect to.
1.11 ericj 813: */
1.21 ericj 814: void
1.37 jakob 815: build_ports(char *p)
1.6 deraadt 816: {
1.88 ray 817: const char *errstr;
818: char *n;
1.21 ericj 819: int hi, lo, cp;
820: int x = 0;
821:
822: if ((n = strchr(p, '-')) != NULL) {
823: *n = '\0';
824: n++;
825:
1.67 jmc 826: /* Make sure the ports are in order: lowest->highest. */
1.88 ray 827: hi = strtonum(n, 1, PORT_MAX, &errstr);
828: if (errstr)
829: errx(1, "port number %s: %s", errstr, n);
830: lo = strtonum(p, 1, PORT_MAX, &errstr);
831: if (errstr)
832: errx(1, "port number %s: %s", errstr, p);
1.21 ericj 833:
834: if (lo > hi) {
835: cp = hi;
836: hi = lo;
837: lo = cp;
838: }
839:
1.67 jmc 840: /* Load ports sequentially. */
1.21 ericj 841: for (cp = lo; cp <= hi; cp++) {
1.55 fgsch 842: portlist[x] = calloc(1, PORT_MAX_LEN);
843: if (portlist[x] == NULL)
844: err(1, NULL);
845: snprintf(portlist[x], PORT_MAX_LEN, "%d", cp);
1.21 ericj 846: x++;
847: }
848:
1.67 jmc 849: /* Randomly swap ports. */
1.21 ericj 850: if (rflag) {
851: int y;
852: char *c;
853:
854: for (x = 0; x <= (hi - lo); x++) {
855: y = (arc4random() & 0xFFFF) % (hi - lo);
856: c = portlist[x];
857: portlist[x] = portlist[y];
858: portlist[y] = c;
1.6 deraadt 859: }
1.11 ericj 860: }
1.21 ericj 861: } else {
1.88 ray 862: hi = strtonum(p, 1, PORT_MAX, &errstr);
863: if (errstr)
864: errx(1, "port number %s: %s", errstr, p);
1.96 nicm 865: portlist[0] = strdup(p);
1.55 fgsch 866: if (portlist[0] == NULL)
867: err(1, NULL);
1.11 ericj 868: }
1.13 ericj 869: }
870:
871: /*
1.21 ericj 872: * udptest()
873: * Do a few writes to see if the UDP port is there.
1.105 lum 874: * Fails once PF state table is full.
1.13 ericj 875: */
1.21 ericj 876: int
1.37 jakob 877: udptest(int s)
1.13 ericj 878: {
1.74 deraadt 879: int i, ret;
1.13 ericj 880:
1.52 vincent 881: for (i = 0; i <= 3; i++) {
1.74 deraadt 882: if (write(s, "X", 1) == 1)
1.21 ericj 883: ret = 1;
1.14 ericj 884: else
1.21 ericj 885: ret = -1;
1.14 ericj 886: }
1.21 ericj 887: return (ret);
1.81 marius 888: }
889:
1.84 dtucker 890: void
1.81 marius 891: set_common_sockopts(int s)
892: {
893: int x = 1;
894:
895: if (Sflag) {
896: if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
897: &x, sizeof(x)) == -1)
898: err(1, NULL);
899: }
900: if (Dflag) {
901: if (setsockopt(s, SOL_SOCKET, SO_DEBUG,
902: &x, sizeof(x)) == -1)
903: err(1, NULL);
904: }
1.83 dtucker 905: if (Tflag != -1) {
906: if (setsockopt(s, IPPROTO_IP, IP_TOS,
907: &Tflag, sizeof(Tflag)) == -1)
908: err(1, "set IP ToS");
909: }
1.90 djm 910: if (Iflag) {
911: if (setsockopt(s, SOL_SOCKET, SO_RCVBUF,
912: &Iflag, sizeof(Iflag)) == -1)
913: err(1, "set TCP receive buffer size");
914: }
915: if (Oflag) {
916: if (setsockopt(s, SOL_SOCKET, SO_SNDBUF,
917: &Oflag, sizeof(Oflag)) == -1)
918: err(1, "set TCP send buffer size");
919: }
1.83 dtucker 920: }
921:
922: int
1.102 haesbaer 923: map_tos(char *s, int *val)
1.83 dtucker 924: {
1.102 haesbaer 925: /* DiffServ Codepoints and other TOS mappings */
926: const struct toskeywords {
927: const char *keyword;
928: int val;
929: } *t, toskeywords[] = {
930: { "af11", IPTOS_DSCP_AF11 },
931: { "af12", IPTOS_DSCP_AF12 },
932: { "af13", IPTOS_DSCP_AF13 },
933: { "af21", IPTOS_DSCP_AF21 },
934: { "af22", IPTOS_DSCP_AF22 },
935: { "af23", IPTOS_DSCP_AF23 },
936: { "af31", IPTOS_DSCP_AF31 },
937: { "af32", IPTOS_DSCP_AF32 },
938: { "af33", IPTOS_DSCP_AF33 },
939: { "af41", IPTOS_DSCP_AF41 },
940: { "af42", IPTOS_DSCP_AF42 },
941: { "af43", IPTOS_DSCP_AF43 },
942: { "critical", IPTOS_PREC_CRITIC_ECP },
943: { "cs0", IPTOS_DSCP_CS0 },
944: { "cs1", IPTOS_DSCP_CS1 },
945: { "cs2", IPTOS_DSCP_CS2 },
946: { "cs3", IPTOS_DSCP_CS3 },
947: { "cs4", IPTOS_DSCP_CS4 },
948: { "cs5", IPTOS_DSCP_CS5 },
949: { "cs6", IPTOS_DSCP_CS6 },
950: { "cs7", IPTOS_DSCP_CS7 },
951: { "ef", IPTOS_DSCP_EF },
952: { "inetcontrol", IPTOS_PREC_INTERNETCONTROL },
953: { "lowdelay", IPTOS_LOWDELAY },
954: { "netcontrol", IPTOS_PREC_NETCONTROL },
955: { "reliability", IPTOS_RELIABILITY },
956: { "throughput", IPTOS_THROUGHPUT },
957: { NULL, -1 },
958: };
959:
960: for (t = toskeywords; t->keyword != NULL; t++) {
961: if (strcmp(s, t->keyword) == 0) {
962: *val = t->val;
963: return (1);
964: }
965: }
1.83 dtucker 966:
1.102 haesbaer 967: return (0);
1.108 ! haesbaer 968: }
! 969:
! 970: void
! 971: report_connect(const struct sockaddr *sa, socklen_t salen)
! 972: {
! 973: char remote_host[NI_MAXHOST];
! 974: char remote_port[NI_MAXSERV];
! 975: int herr;
! 976: int flags = NI_NUMERICSERV;
! 977:
! 978: if (nflag)
! 979: flags |= NI_NUMERICHOST;
! 980:
! 981: if ((herr = getnameinfo(sa, salen,
! 982: remote_host, sizeof(remote_host),
! 983: remote_port, sizeof(remote_port),
! 984: flags)) != 0) {
! 985: if (herr == EAI_SYSTEM)
! 986: err(1, "getnameinfo");
! 987: else
! 988: errx(1, "getnameinfo: %s", gai_strerror(herr));
! 989: }
! 990:
! 991: fprintf(stderr,
! 992: "Connection from %s %s "
! 993: "received!\n", remote_host, remote_port);
1.7 deraadt 994: }
1.1 deraadt 995:
1.11 ericj 996: void
1.58 deraadt 997: help(void)
1.1 deraadt 998: {
1.21 ericj 999: usage(0);
1000: fprintf(stderr, "\tCommand Summary:\n\
1001: \t-4 Use IPv4\n\
1002: \t-6 Use IPv6\n\
1.73 markus 1003: \t-D Enable the debug socket option\n\
1.69 tedu 1004: \t-d Detach from stdin\n\
1.21 ericj 1005: \t-h This help text\n\
1.90 djm 1006: \t-I length TCP receive buffer length\n\
1.21 ericj 1007: \t-i secs\t Delay interval for lines sent, ports scanned\n\
1008: \t-k Keep inbound sockets open for multiple connects\n\
1009: \t-l Listen mode, for inbound connects\n\
1.22 jasoni 1010: \t-n Suppress name/port resolutions\n\
1.90 djm 1011: \t-O length TCP send buffer length\n\
1.86 djm 1012: \t-P proxyuser\tUsername for proxy authentication\n\
1.36 jakob 1013: \t-p port\t Specify local port for remote connects\n\
1.21 ericj 1014: \t-r Randomize remote ports\n\
1.67 jmc 1015: \t-S Enable the TCP MD5 signature option\n\
1.21 ericj 1016: \t-s addr\t Local source address\n\
1.102 haesbaer 1017: \t-T toskeyword\tSet IP Type of Service\n\
1.21 ericj 1018: \t-t Answer TELNET negotiation\n\
1.67 jmc 1019: \t-U Use UNIX domain socket\n\
1.21 ericj 1020: \t-u UDP mode\n\
1.98 guenther 1021: \t-V rtable Specify alternate routing table\n\
1.21 ericj 1022: \t-v Verbose\n\
1023: \t-w secs\t Timeout for connects and final net reads\n\
1.75 djm 1024: \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\
1025: \t-x addr[:port]\tSpecify proxy address and port\n\
1.21 ericj 1026: \t-z Zero-I/O mode [used for scanning]\n\
1027: Port numbers can be individual or ranges: lo-hi [inclusive]\n");
1028: exit(1);
1.11 ericj 1029: }
1030:
1031: void
1.37 jakob 1032: usage(int ret)
1.11 ericj 1033: {
1.92 sobrado 1034: fprintf(stderr,
1035: "usage: nc [-46DdhklnrStUuvz] [-I length] [-i interval] [-O length]\n"
1.100 jeremy 1036: "\t [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n"
1.98 guenther 1037: "\t [-V rtable] [-w timeout] [-X proxy_protocol]\n"
1.100 jeremy 1038: "\t [-x proxy_address[:port]] [destination] [port]\n");
1.21 ericj 1039: if (ret)
1040: exit(1);
1.7 deraadt 1041: }
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