Annotation of src/usr.bin/nc/netcat.c, Revision 1.102
1.102 ! haesbaer 1: /* $OpenBSD: netcat.c,v 1.101 2011/06/21 17:31:07 mikeb 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 */
1.80 mcbride 70: int jflag; /* use jumbo frames if we can */
1.21 ericj 71: int kflag; /* More than one connect */
72: int lflag; /* Bind to local port */
1.67 jmc 73: int nflag; /* Don't do name look up */
1.86 djm 74: char *Pflag; /* Proxy username */
1.21 ericj 75: char *pflag; /* Localport flag */
76: int rflag; /* Random ports flag */
77: char *sflag; /* Source Address */
78: int tflag; /* Telnet Emulation */
79: int uflag; /* UDP - Default to TCP */
80: int vflag; /* Verbosity */
1.34 jakob 81: int xflag; /* Socks proxy */
1.21 ericj 82: int zflag; /* Port Scan Flag */
1.73 markus 83: int Dflag; /* sodebug */
1.90 djm 84: int Iflag; /* TCP receive buffer size */
85: int Oflag; /* TCP send buffer size */
1.65 markus 86: int Sflag; /* TCP MD5 signature option */
1.83 dtucker 87: int Tflag = -1; /* IP Type of Service */
1.98 guenther 88: u_int rtableid;
1.21 ericj 89:
1.49 hugh 90: int timeout = -1;
1.21 ericj 91: int family = AF_UNSPEC;
1.63 miod 92: char *portlist[PORT_MAX+1];
1.99 jeremy 93: char *unix_dg_tmp_socket;
1.21 ericj 94:
1.40 millert 95: void atelnet(int, unsigned char *, unsigned int);
96: void build_ports(char *);
97: void help(void);
98: int local_listen(char *, char *, struct addrinfo);
99: void readwrite(int);
1.77 otto 100: int remote_connect(const char *, const char *, struct addrinfo);
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 *);
1.40 millert 109: void usage(int);
1.1 deraadt 110:
1.21 ericj 111: int
1.37 jakob 112: main(int argc, char *argv[])
1.21 ericj 113: {
1.46 markus 114: int ch, s, ret, socksv;
1.88 ray 115: char *host, *uport;
1.21 ericj 116: struct addrinfo hints;
1.29 smart 117: struct servent *sv;
1.21 ericj 118: socklen_t len;
1.76 hshoexer 119: struct sockaddr_storage cliaddr;
1.34 jakob 120: char *proxy;
1.88 ray 121: const char *errstr, *proxyhost = "", *proxyport = NULL;
1.34 jakob 122: struct addrinfo proxyhints;
1.99 jeremy 123: char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE];
1.11 ericj 124:
1.29 smart 125: ret = 1;
126: s = 0;
1.46 markus 127: socksv = 5;
1.29 smart 128: host = NULL;
129: uport = NULL;
130: sv = NULL;
131:
1.80 mcbride 132: while ((ch = getopt(argc, argv,
1.93 claudio 133: "46DdhI:i:jklnO:P:p:rSs:tT:UuV:vw:X:x:z")) != -1) {
1.21 ericj 134: switch (ch) {
135: case '4':
136: family = AF_INET;
137: break;
138: case '6':
139: family = AF_INET6;
140: break;
1.42 ericj 141: case 'U':
142: family = AF_UNIX;
143: break;
1.46 markus 144: case 'X':
1.75 djm 145: if (strcasecmp(optarg, "connect") == 0)
146: socksv = -1; /* HTTP proxy CONNECT */
147: else if (strcmp(optarg, "4") == 0)
148: socksv = 4; /* SOCKS v.4 */
149: else if (strcmp(optarg, "5") == 0)
150: socksv = 5; /* SOCKS v.5 */
151: else
152: errx(1, "unsupported proxy protocol");
1.46 markus 153: break;
1.68 tedu 154: case 'd':
155: dflag = 1;
156: break;
1.21 ericj 157: case 'h':
158: help();
159: break;
160: case 'i':
1.88 ray 161: iflag = strtonum(optarg, 0, UINT_MAX, &errstr);
162: if (errstr)
163: errx(1, "interval %s: %s", errstr, optarg);
1.21 ericj 164: break;
1.80 mcbride 165: case 'j':
166: jflag = 1;
167: break;
1.21 ericj 168: case 'k':
169: kflag = 1;
170: break;
171: case 'l':
172: lflag = 1;
173: break;
174: case 'n':
175: nflag = 1;
176: break;
1.86 djm 177: case 'P':
178: Pflag = optarg;
179: break;
1.21 ericj 180: case 'p':
181: pflag = optarg;
182: break;
183: case 'r':
184: rflag = 1;
185: break;
186: case 's':
187: sflag = optarg;
188: break;
189: case 't':
190: tflag = 1;
191: break;
192: case 'u':
193: uflag = 1;
194: break;
1.93 claudio 195: case 'V':
1.98 guenther 196: rtableid = (unsigned int)strtonum(optarg, 0,
1.93 claudio 197: RT_TABLEID_MAX, &errstr);
198: if (errstr)
1.98 guenther 199: errx(1, "rtable %s: %s", errstr, optarg);
1.93 claudio 200: break;
1.21 ericj 201: case 'v':
202: vflag = 1;
203: break;
1.70 deraadt 204: case 'w':
1.88 ray 205: timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr);
206: if (errstr)
207: errx(1, "timeout %s: %s", errstr, optarg);
1.49 hugh 208: timeout *= 1000;
1.21 ericj 209: break;
1.34 jakob 210: case 'x':
211: xflag = 1;
1.64 deraadt 212: if ((proxy = strdup(optarg)) == NULL)
213: err(1, NULL);
1.34 jakob 214: break;
1.21 ericj 215: case 'z':
216: zflag = 1;
217: break;
1.73 markus 218: case 'D':
219: Dflag = 1;
220: break;
1.90 djm 221: case 'I':
222: Iflag = strtonum(optarg, 1, 65536 << 14, &errstr);
223: if (errstr != NULL)
224: errx(1, "TCP receive window %s: %s",
225: errstr, optarg);
226: break;
227: case 'O':
228: Oflag = strtonum(optarg, 1, 65536 << 14, &errstr);
229: if (errstr != NULL)
230: errx(1, "TCP send window %s: %s",
231: errstr, optarg);
232: break;
1.65 markus 233: case 'S':
234: Sflag = 1;
235: break;
1.83 dtucker 236: case 'T':
1.102 ! haesbaer 237: errstr = NULL;
! 238: errno = 0;
! 239: if (map_tos(optarg, &Tflag))
! 240: break;
! 241: if (strlen(optarg) > 1 && optarg[0] == '0' &&
! 242: optarg[1] == 'x')
! 243: Tflag = (int)strtol(optarg, NULL, 16);
! 244: else
! 245: Tflag = (int)strtonum(optarg, 0, 255,
! 246: &errstr);
! 247: if (Tflag < 0 || Tflag > 255 || errstr || errno)
! 248: errx(1, "illegal tos value %s", optarg);
1.83 dtucker 249: break;
1.21 ericj 250: default:
251: usage(1);
252: }
253: }
254: argc -= optind;
255: argv += optind;
1.11 ericj 256:
1.21 ericj 257: /* Cruft to make sure options are clean, and used properly. */
1.42 ericj 258: if (argv[0] && !argv[1] && family == AF_UNIX) {
259: host = argv[0];
260: uport = NULL;
261: } else if (argv[0] && !argv[1]) {
1.21 ericj 262: if (!lflag)
263: usage(1);
264: uport = argv[0];
265: host = NULL;
266: } else if (argv[0] && argv[1]) {
267: host = argv[0];
268: uport = argv[1];
269: } else
270: usage(1);
1.1 deraadt 271:
1.21 ericj 272: if (lflag && sflag)
273: errx(1, "cannot use -s and -l");
274: if (lflag && pflag)
275: errx(1, "cannot use -p and -l");
276: if (lflag && zflag)
1.32 ericj 277: errx(1, "cannot use -z and -l");
1.21 ericj 278: if (!lflag && kflag)
1.32 ericj 279: errx(1, "must use -l with -k");
1.21 ericj 280:
1.99 jeremy 281: /* Get name of temporary socket for unix datagram client */
282: if ((family == AF_UNIX) && uflag && !lflag) {
283: if (sflag) {
284: unix_dg_tmp_socket = sflag;
285: } else {
286: strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX",
287: UNIX_DG_TMP_SOCKET_SIZE);
288: if (mktemp(unix_dg_tmp_socket_buf) == NULL)
289: err(1, "mktemp");
290: unix_dg_tmp_socket = unix_dg_tmp_socket_buf;
291: }
292: }
293:
1.67 jmc 294: /* Initialize addrinfo structure. */
1.42 ericj 295: if (family != AF_UNIX) {
296: memset(&hints, 0, sizeof(struct addrinfo));
297: hints.ai_family = family;
298: hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
299: hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
300: if (nflag)
301: hints.ai_flags |= AI_NUMERICHOST;
302: }
1.1 deraadt 303:
1.34 jakob 304: if (xflag) {
305: if (uflag)
306: errx(1, "no proxy support for UDP mode");
307:
308: if (lflag)
309: errx(1, "no proxy support for listen");
310:
1.42 ericj 311: if (family == AF_UNIX)
312: errx(1, "no proxy support for unix sockets");
313:
1.34 jakob 314: /* XXX IPv6 transport to proxy would probably work */
315: if (family == AF_INET6)
316: errx(1, "no proxy support for IPv6");
317:
318: if (sflag)
319: errx(1, "no proxy support for local source address");
320:
321: proxyhost = strsep(&proxy, ":");
322: proxyport = proxy;
323:
324: memset(&proxyhints, 0, sizeof(struct addrinfo));
325: proxyhints.ai_family = family;
326: proxyhints.ai_socktype = SOCK_STREAM;
327: proxyhints.ai_protocol = IPPROTO_TCP;
328: if (nflag)
329: proxyhints.ai_flags |= AI_NUMERICHOST;
330: }
331:
1.21 ericj 332: if (lflag) {
333: int connfd;
1.27 ericj 334: ret = 0;
1.1 deraadt 335:
1.99 jeremy 336: if (family == AF_UNIX) {
337: if (uflag)
338: s = unix_bind(host);
339: else
340: s = unix_listen(host);
341: }
1.42 ericj 342:
1.67 jmc 343: /* Allow only one connection at a time, but stay alive. */
1.21 ericj 344: for (;;) {
1.42 ericj 345: if (family != AF_UNIX)
346: s = local_listen(host, uport, hints);
347: if (s < 0)
1.30 smart 348: err(1, NULL);
1.21 ericj 349: /*
350: * For UDP, we will use recvfrom() initially
351: * to wait for a caller, then use the regular
352: * functions to talk to the caller.
353: */
354: if (uflag) {
1.80 mcbride 355: int rv, plen;
1.97 nicm 356: char buf[16384];
1.21 ericj 357: struct sockaddr_storage z;
358:
359: len = sizeof(z);
1.97 nicm 360: plen = jflag ? 16384 : 2048;
1.80 mcbride 361: rv = recvfrom(s, buf, plen, MSG_PEEK,
1.37 jakob 362: (struct sockaddr *)&z, &len);
1.23 ericj 363: if (rv < 0)
1.57 stevesk 364: err(1, "recvfrom");
1.21 ericj 365:
1.37 jakob 366: rv = connect(s, (struct sockaddr *)&z, len);
1.23 ericj 367: if (rv < 0)
1.57 stevesk 368: err(1, "connect");
1.1 deraadt 369:
1.99 jeremy 370: readwrite(s);
1.21 ericj 371: } else {
1.78 otto 372: len = sizeof(cliaddr);
1.21 ericj 373: connfd = accept(s, (struct sockaddr *)&cliaddr,
1.37 jakob 374: &len);
1.99 jeremy 375: readwrite(connfd);
376: close(connfd);
1.21 ericj 377: }
1.1 deraadt 378:
1.42 ericj 379: if (family != AF_UNIX)
380: close(s);
1.99 jeremy 381: else if (uflag) {
382: if (connect(s, NULL, 0) < 0)
383: err(1, "connect");
384: }
1.27 ericj 385:
1.21 ericj 386: if (!kflag)
387: break;
1.11 ericj 388: }
1.42 ericj 389: } else if (family == AF_UNIX) {
390: ret = 0;
391:
392: if ((s = unix_connect(host)) > 0 && !zflag) {
393: readwrite(s);
394: close(s);
395: } else
396: ret = 1;
397:
1.99 jeremy 398: if (uflag)
399: unlink(unix_dg_tmp_socket);
1.42 ericj 400: exit(ret);
401:
1.21 ericj 402: } else {
403: int i = 0;
1.6 deraadt 404:
1.67 jmc 405: /* Construct the portlist[] array. */
1.21 ericj 406: build_ports(uport);
1.1 deraadt 407:
1.67 jmc 408: /* Cycle through portlist, connecting to each port. */
1.21 ericj 409: for (i = 0; portlist[i] != NULL; i++) {
410: if (s)
411: close(s);
1.34 jakob 412:
413: if (xflag)
414: s = socks_connect(host, portlist[i], hints,
1.86 djm 415: proxyhost, proxyport, proxyhints, socksv,
416: Pflag);
1.34 jakob 417: else
418: s = remote_connect(host, portlist[i], hints);
419:
420: if (s < 0)
1.21 ericj 421: continue;
1.1 deraadt 422:
1.21 ericj 423: ret = 0;
424: if (vflag || zflag) {
1.67 jmc 425: /* For UDP, make sure we are connected. */
1.21 ericj 426: if (uflag) {
1.50 vincent 427: if (udptest(s) == -1) {
1.21 ericj 428: ret = 1;
429: continue;
430: }
431: }
1.1 deraadt 432:
1.67 jmc 433: /* Don't look up port if -n. */
1.21 ericj 434: if (nflag)
435: sv = NULL;
436: else {
437: sv = getservbyport(
1.37 jakob 438: ntohs(atoi(portlist[i])),
439: uflag ? "udp" : "tcp");
1.21 ericj 440: }
1.50 vincent 441:
1.94 mpf 442: fprintf(stderr,
443: "Connection to %s %s port [%s/%s] "
444: "succeeded!\n", host, portlist[i],
445: uflag ? "udp" : "tcp",
1.37 jakob 446: sv ? sv->s_name : "*");
1.21 ericj 447: }
448: if (!zflag)
449: readwrite(s);
1.7 deraadt 450: }
1.11 ericj 451: }
1.1 deraadt 452:
1.21 ericj 453: if (s)
454: close(s);
455:
456: exit(ret);
1.7 deraadt 457: }
1.1 deraadt 458:
1.11 ericj 459: /*
1.99 jeremy 460: * unix_bind()
461: * Returns a unix socket bound to the given path
1.42 ericj 462: */
463: int
1.99 jeremy 464: unix_bind(char *path)
1.42 ericj 465: {
466: struct sockaddr_un sun;
467: int s;
468:
1.99 jeremy 469: /* Create unix domain socket. */
470: if ((s = socket(AF_UNIX, uflag ? SOCK_DGRAM : SOCK_STREAM,
471: 0)) < 0)
1.50 vincent 472: return (-1);
1.42 ericj 473:
474: memset(&sun, 0, sizeof(struct sockaddr_un));
475: sun.sun_family = AF_UNIX;
1.60 avsm 476:
477: if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
478: sizeof(sun.sun_path)) {
479: close(s);
480: errno = ENAMETOOLONG;
481: return (-1);
482: }
1.99 jeremy 483:
484: if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
1.50 vincent 485: close(s);
486: return (-1);
1.42 ericj 487: }
488: return (s);
489: }
490:
491: /*
1.99 jeremy 492: * unix_connect()
493: * Returns a socket connected to a local unix socket. Returns -1 on failure.
1.42 ericj 494: */
495: int
1.99 jeremy 496: unix_connect(char *path)
1.42 ericj 497: {
498: struct sockaddr_un sun;
499: int s;
500:
1.99 jeremy 501: if (uflag) {
502: if ((s = unix_bind(unix_dg_tmp_socket)) < 0)
503: return (-1);
504: } else {
505: if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
506: return (-1);
507: }
508: (void)fcntl(s, F_SETFD, 1);
1.42 ericj 509:
1.60 avsm 510: memset(&sun, 0, sizeof(struct sockaddr_un));
1.42 ericj 511: sun.sun_family = AF_UNIX;
1.60 avsm 512:
513: if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
514: sizeof(sun.sun_path)) {
515: close(s);
516: errno = ENAMETOOLONG;
517: return (-1);
518: }
1.99 jeremy 519: if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
1.42 ericj 520: close(s);
521: return (-1);
522: }
1.99 jeremy 523: return (s);
524:
525: }
526:
527: /*
528: * unix_listen()
529: * Create a unix domain socket, and listen on it.
530: */
531: int
532: unix_listen(char *path)
533: {
534: int s;
535: if ((s = unix_bind(path)) < 0)
536: return (-1);
1.42 ericj 537:
538: if (listen(s, 5) < 0) {
539: close(s);
540: return (-1);
541: }
542: return (s);
543: }
544:
545: /*
1.21 ericj 546: * remote_connect()
1.67 jmc 547: * Returns a socket connected to a remote host. Properly binds to a local
548: * port or source address if needed. Returns -1 on failure.
1.11 ericj 549: */
1.21 ericj 550: int
1.77 otto 551: remote_connect(const char *host, const char *port, struct addrinfo hints)
1.21 ericj 552: {
553: struct addrinfo *res, *res0;
1.91 markus 554: int s, error, on = 1;
1.21 ericj 555:
556: if ((error = getaddrinfo(host, port, &hints, &res)))
1.56 stevesk 557: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.21 ericj 558:
559: res0 = res;
560: do {
561: if ((s = socket(res0->ai_family, res0->ai_socktype,
1.37 jakob 562: res0->ai_protocol)) < 0)
1.21 ericj 563: continue;
564:
1.98 guenther 565: if (rtableid) {
1.101 mikeb 566: if (setsockopt(s, SOL_SOCKET, SO_RTABLE, &rtableid,
1.98 guenther 567: sizeof(rtableid)) == -1)
568: err(1, "setsockopt SO_RTABLE");
1.93 claudio 569: }
570:
1.67 jmc 571: /* Bind to a local port or source address if specified. */
1.21 ericj 572: if (sflag || pflag) {
573: struct addrinfo ahints, *ares;
1.6 deraadt 574:
1.91 markus 575: /* try SO_BINDANY, but don't insist */
576: setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on));
1.21 ericj 577: memset(&ahints, 0, sizeof(struct addrinfo));
578: ahints.ai_family = res0->ai_family;
579: ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
580: ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
1.25 ericj 581: ahints.ai_flags = AI_PASSIVE;
1.38 jakob 582: if ((error = getaddrinfo(sflag, pflag, &ahints, &ares)))
1.56 stevesk 583: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.21 ericj 584:
585: if (bind(s, (struct sockaddr *)ares->ai_addr,
1.62 millert 586: ares->ai_addrlen) < 0)
1.21 ericj 587: errx(1, "bind failed: %s", strerror(errno));
588: freeaddrinfo(ares);
1.6 deraadt 589: }
1.81 marius 590:
591: set_common_sockopts(s);
1.6 deraadt 592:
1.21 ericj 593: if (connect(s, res0->ai_addr, res0->ai_addrlen) == 0)
1.6 deraadt 594: break;
1.71 mcbride 595: else if (vflag)
596: warn("connect to %s port %s (%s) failed", host, port,
597: uflag ? "udp" : "tcp");
1.34 jakob 598:
1.21 ericj 599: close(s);
600: s = -1;
601: } while ((res0 = res0->ai_next) != NULL);
602:
603: freeaddrinfo(res);
1.1 deraadt 604:
1.21 ericj 605: return (s);
1.7 deraadt 606: }
1.1 deraadt 607:
1.11 ericj 608: /*
1.21 ericj 609: * local_listen()
1.67 jmc 610: * Returns a socket listening on a local port, binds to specified source
611: * address. Returns -1 on failure.
1.11 ericj 612: */
1.21 ericj 613: int
1.37 jakob 614: local_listen(char *host, char *port, struct addrinfo hints)
1.21 ericj 615: {
616: struct addrinfo *res, *res0;
617: int s, ret, x = 1;
618: int error;
1.6 deraadt 619:
1.67 jmc 620: /* Allow nodename to be null. */
1.21 ericj 621: hints.ai_flags |= AI_PASSIVE;
1.7 deraadt 622:
1.21 ericj 623: /*
624: * In the case of binding to a wildcard address
625: * default to binding to an ipv4 address.
626: */
627: if (host == NULL && hints.ai_family == AF_UNSPEC)
628: hints.ai_family = AF_INET;
1.1 deraadt 629:
1.21 ericj 630: if ((error = getaddrinfo(host, port, &hints, &res)))
1.70 deraadt 631: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.14 ericj 632:
1.21 ericj 633: res0 = res;
634: do {
635: if ((s = socket(res0->ai_family, res0->ai_socktype,
1.82 marius 636: res0->ai_protocol)) < 0)
1.21 ericj 637: continue;
1.1 deraadt 638:
1.98 guenther 639: if (rtableid) {
640: if (setsockopt(s, IPPROTO_IP, SO_RTABLE, &rtableid,
641: sizeof(rtableid)) == -1)
642: err(1, "setsockopt SO_RTABLE");
1.93 claudio 643: }
644:
1.21 ericj 645: ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x));
646: if (ret == -1)
1.30 smart 647: err(1, NULL);
1.81 marius 648:
649: set_common_sockopts(s);
1.1 deraadt 650:
1.21 ericj 651: if (bind(s, (struct sockaddr *)res0->ai_addr,
1.37 jakob 652: res0->ai_addrlen) == 0)
1.21 ericj 653: break;
1.1 deraadt 654:
1.21 ericj 655: close(s);
656: s = -1;
657: } while ((res0 = res0->ai_next) != NULL);
1.1 deraadt 658:
1.47 ericj 659: if (!uflag && s != -1) {
1.21 ericj 660: if (listen(s, 1) < 0)
1.57 stevesk 661: err(1, "listen");
1.12 ericj 662: }
1.1 deraadt 663:
1.21 ericj 664: freeaddrinfo(res);
1.1 deraadt 665:
1.21 ericj 666: return (s);
1.7 deraadt 667: }
668:
1.11 ericj 669: /*
1.21 ericj 670: * readwrite()
671: * Loop that polls on the network file descriptor and stdin.
1.11 ericj 672: */
1.21 ericj 673: void
1.37 jakob 674: readwrite(int nfd)
1.6 deraadt 675: {
1.52 vincent 676: struct pollfd pfd[2];
1.97 nicm 677: unsigned char buf[16384];
1.79 avsm 678: int n, wfd = fileno(stdin);
1.21 ericj 679: int lfd = fileno(stdout);
1.80 mcbride 680: int plen;
681:
1.97 nicm 682: plen = jflag ? 16384 : 2048;
1.21 ericj 683:
684: /* Setup Network FD */
685: pfd[0].fd = nfd;
686: pfd[0].events = POLLIN;
687:
1.67 jmc 688: /* Set up STDIN FD. */
1.21 ericj 689: pfd[1].fd = wfd;
690: pfd[1].events = POLLIN;
691:
1.54 aaron 692: while (pfd[0].fd != -1) {
1.21 ericj 693: if (iflag)
694: sleep(iflag);
695:
1.68 tedu 696: if ((n = poll(pfd, 2 - dflag, timeout)) < 0) {
1.21 ericj 697: close(nfd);
1.52 vincent 698: err(1, "Polling Error");
1.21 ericj 699: }
1.49 hugh 700:
701: if (n == 0)
702: return;
1.21 ericj 703:
704: if (pfd[0].revents & POLLIN) {
1.80 mcbride 705: if ((n = read(nfd, buf, plen)) < 0)
1.21 ericj 706: return;
1.52 vincent 707: else if (n == 0) {
708: shutdown(nfd, SHUT_RD);
709: pfd[0].fd = -1;
710: pfd[0].events = 0;
1.21 ericj 711: } else {
712: if (tflag)
713: atelnet(nfd, buf, n);
1.79 avsm 714: if (atomicio(vwrite, lfd, buf, n) != n)
1.21 ericj 715: return;
1.6 deraadt 716: }
1.21 ericj 717: }
718:
1.68 tedu 719: if (!dflag && pfd[1].revents & POLLIN) {
1.80 mcbride 720: if ((n = read(wfd, buf, plen)) < 0)
1.21 ericj 721: return;
1.52 vincent 722: else if (n == 0) {
723: shutdown(nfd, SHUT_WR);
724: pfd[1].fd = -1;
725: pfd[1].events = 0;
726: } else {
1.79 avsm 727: if (atomicio(vwrite, nfd, buf, n) != n)
1.21 ericj 728: return;
1.50 vincent 729: }
1.21 ericj 730: }
1.11 ericj 731: }
1.7 deraadt 732: }
1.50 vincent 733:
1.67 jmc 734: /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */
1.21 ericj 735: void
1.37 jakob 736: atelnet(int nfd, unsigned char *buf, unsigned int size)
1.6 deraadt 737: {
1.24 ericj 738: unsigned char *p, *end;
739: unsigned char obuf[4];
740:
1.95 nicm 741: if (size < 3)
742: return;
743: end = buf + size - 2;
1.24 ericj 744:
745: for (p = buf; p < end; p++) {
1.21 ericj 746: if (*p != IAC)
1.95 nicm 747: continue;
1.24 ericj 748:
1.25 ericj 749: obuf[0] = IAC;
1.24 ericj 750: p++;
1.50 vincent 751: if ((*p == WILL) || (*p == WONT))
1.24 ericj 752: obuf[1] = DONT;
1.95 nicm 753: else if ((*p == DO) || (*p == DONT))
1.24 ericj 754: obuf[1] = WONT;
1.95 nicm 755: else
756: continue;
757:
758: p++;
759: obuf[2] = *p;
760: if (atomicio(vwrite, nfd, obuf, 3) != 3)
761: warn("Write Error!");
1.11 ericj 762: }
1.7 deraadt 763: }
764:
1.11 ericj 765: /*
1.21 ericj 766: * build_ports()
767: * Build an array or ports in portlist[], listing each port
1.67 jmc 768: * that we should try to connect to.
1.11 ericj 769: */
1.21 ericj 770: void
1.37 jakob 771: build_ports(char *p)
1.6 deraadt 772: {
1.88 ray 773: const char *errstr;
774: char *n;
1.21 ericj 775: int hi, lo, cp;
776: int x = 0;
777:
778: if ((n = strchr(p, '-')) != NULL) {
779: if (lflag)
780: errx(1, "Cannot use -l with multiple ports!");
781:
782: *n = '\0';
783: n++;
784:
1.67 jmc 785: /* Make sure the ports are in order: lowest->highest. */
1.88 ray 786: hi = strtonum(n, 1, PORT_MAX, &errstr);
787: if (errstr)
788: errx(1, "port number %s: %s", errstr, n);
789: lo = strtonum(p, 1, PORT_MAX, &errstr);
790: if (errstr)
791: errx(1, "port number %s: %s", errstr, p);
1.21 ericj 792:
793: if (lo > hi) {
794: cp = hi;
795: hi = lo;
796: lo = cp;
797: }
798:
1.67 jmc 799: /* Load ports sequentially. */
1.21 ericj 800: for (cp = lo; cp <= hi; cp++) {
1.55 fgsch 801: portlist[x] = calloc(1, PORT_MAX_LEN);
802: if (portlist[x] == NULL)
803: err(1, NULL);
804: snprintf(portlist[x], PORT_MAX_LEN, "%d", cp);
1.21 ericj 805: x++;
806: }
807:
1.67 jmc 808: /* Randomly swap ports. */
1.21 ericj 809: if (rflag) {
810: int y;
811: char *c;
812:
813: for (x = 0; x <= (hi - lo); x++) {
814: y = (arc4random() & 0xFFFF) % (hi - lo);
815: c = portlist[x];
816: portlist[x] = portlist[y];
817: portlist[y] = c;
1.6 deraadt 818: }
1.11 ericj 819: }
1.21 ericj 820: } else {
1.88 ray 821: hi = strtonum(p, 1, PORT_MAX, &errstr);
822: if (errstr)
823: errx(1, "port number %s: %s", errstr, p);
1.96 nicm 824: portlist[0] = strdup(p);
1.55 fgsch 825: if (portlist[0] == NULL)
826: err(1, NULL);
1.11 ericj 827: }
1.13 ericj 828: }
829:
830: /*
1.21 ericj 831: * udptest()
832: * Do a few writes to see if the UDP port is there.
1.67 jmc 833: * XXX - Better way of doing this? Doesn't work for IPv6.
1.21 ericj 834: * Also fails after around 100 ports checked.
1.13 ericj 835: */
1.21 ericj 836: int
1.37 jakob 837: udptest(int s)
1.13 ericj 838: {
1.74 deraadt 839: int i, ret;
1.13 ericj 840:
1.52 vincent 841: for (i = 0; i <= 3; i++) {
1.74 deraadt 842: if (write(s, "X", 1) == 1)
1.21 ericj 843: ret = 1;
1.14 ericj 844: else
1.21 ericj 845: ret = -1;
1.14 ericj 846: }
1.21 ericj 847: return (ret);
1.81 marius 848: }
849:
1.84 dtucker 850: void
1.81 marius 851: set_common_sockopts(int s)
852: {
853: int x = 1;
854:
855: if (Sflag) {
856: if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
857: &x, sizeof(x)) == -1)
858: err(1, NULL);
859: }
860: if (Dflag) {
861: if (setsockopt(s, SOL_SOCKET, SO_DEBUG,
862: &x, sizeof(x)) == -1)
863: err(1, NULL);
864: }
865: if (jflag) {
866: if (setsockopt(s, SOL_SOCKET, SO_JUMBO,
867: &x, sizeof(x)) == -1)
868: err(1, NULL);
869: }
1.83 dtucker 870: if (Tflag != -1) {
871: if (setsockopt(s, IPPROTO_IP, IP_TOS,
872: &Tflag, sizeof(Tflag)) == -1)
873: err(1, "set IP ToS");
874: }
1.90 djm 875: if (Iflag) {
876: if (setsockopt(s, SOL_SOCKET, SO_RCVBUF,
877: &Iflag, sizeof(Iflag)) == -1)
878: err(1, "set TCP receive buffer size");
879: }
880: if (Oflag) {
881: if (setsockopt(s, SOL_SOCKET, SO_SNDBUF,
882: &Oflag, sizeof(Oflag)) == -1)
883: err(1, "set TCP send buffer size");
884: }
1.83 dtucker 885: }
886:
887: int
1.102 ! haesbaer 888: map_tos(char *s, int *val)
1.83 dtucker 889: {
1.102 ! haesbaer 890: /* DiffServ Codepoints and other TOS mappings */
! 891: const struct toskeywords {
! 892: const char *keyword;
! 893: int val;
! 894: } *t, toskeywords[] = {
! 895: { "af11", IPTOS_DSCP_AF11 },
! 896: { "af12", IPTOS_DSCP_AF12 },
! 897: { "af13", IPTOS_DSCP_AF13 },
! 898: { "af21", IPTOS_DSCP_AF21 },
! 899: { "af22", IPTOS_DSCP_AF22 },
! 900: { "af23", IPTOS_DSCP_AF23 },
! 901: { "af31", IPTOS_DSCP_AF31 },
! 902: { "af32", IPTOS_DSCP_AF32 },
! 903: { "af33", IPTOS_DSCP_AF33 },
! 904: { "af41", IPTOS_DSCP_AF41 },
! 905: { "af42", IPTOS_DSCP_AF42 },
! 906: { "af43", IPTOS_DSCP_AF43 },
! 907: { "critical", IPTOS_PREC_CRITIC_ECP },
! 908: { "cs0", IPTOS_DSCP_CS0 },
! 909: { "cs1", IPTOS_DSCP_CS1 },
! 910: { "cs2", IPTOS_DSCP_CS2 },
! 911: { "cs3", IPTOS_DSCP_CS3 },
! 912: { "cs4", IPTOS_DSCP_CS4 },
! 913: { "cs5", IPTOS_DSCP_CS5 },
! 914: { "cs6", IPTOS_DSCP_CS6 },
! 915: { "cs7", IPTOS_DSCP_CS7 },
! 916: { "ef", IPTOS_DSCP_EF },
! 917: { "inetcontrol", IPTOS_PREC_INTERNETCONTROL },
! 918: { "lowdelay", IPTOS_LOWDELAY },
! 919: { "netcontrol", IPTOS_PREC_NETCONTROL },
! 920: { "reliability", IPTOS_RELIABILITY },
! 921: { "throughput", IPTOS_THROUGHPUT },
! 922: { NULL, -1 },
! 923: };
! 924:
! 925: for (t = toskeywords; t->keyword != NULL; t++) {
! 926: if (strcmp(s, t->keyword) == 0) {
! 927: *val = t->val;
! 928: return (1);
! 929: }
! 930: }
1.83 dtucker 931:
1.102 ! haesbaer 932: return (0);
1.7 deraadt 933: }
1.1 deraadt 934:
1.11 ericj 935: void
1.58 deraadt 936: help(void)
1.1 deraadt 937: {
1.21 ericj 938: usage(0);
939: fprintf(stderr, "\tCommand Summary:\n\
940: \t-4 Use IPv4\n\
941: \t-6 Use IPv6\n\
1.73 markus 942: \t-D Enable the debug socket option\n\
1.69 tedu 943: \t-d Detach from stdin\n\
1.21 ericj 944: \t-h This help text\n\
1.90 djm 945: \t-I length TCP receive buffer length\n\
1.21 ericj 946: \t-i secs\t Delay interval for lines sent, ports scanned\n\
947: \t-k Keep inbound sockets open for multiple connects\n\
948: \t-l Listen mode, for inbound connects\n\
1.22 jasoni 949: \t-n Suppress name/port resolutions\n\
1.90 djm 950: \t-O length TCP send buffer length\n\
1.86 djm 951: \t-P proxyuser\tUsername for proxy authentication\n\
1.36 jakob 952: \t-p port\t Specify local port for remote connects\n\
1.21 ericj 953: \t-r Randomize remote ports\n\
1.67 jmc 954: \t-S Enable the TCP MD5 signature option\n\
1.21 ericj 955: \t-s addr\t Local source address\n\
1.102 ! haesbaer 956: \t-T toskeyword\tSet IP Type of Service\n\
1.21 ericj 957: \t-t Answer TELNET negotiation\n\
1.67 jmc 958: \t-U Use UNIX domain socket\n\
1.21 ericj 959: \t-u UDP mode\n\
1.98 guenther 960: \t-V rtable Specify alternate routing table\n\
1.21 ericj 961: \t-v Verbose\n\
962: \t-w secs\t Timeout for connects and final net reads\n\
1.75 djm 963: \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\
964: \t-x addr[:port]\tSpecify proxy address and port\n\
1.21 ericj 965: \t-z Zero-I/O mode [used for scanning]\n\
966: Port numbers can be individual or ranges: lo-hi [inclusive]\n");
967: exit(1);
1.11 ericj 968: }
969:
970: void
1.37 jakob 971: usage(int ret)
1.11 ericj 972: {
1.92 sobrado 973: fprintf(stderr,
974: "usage: nc [-46DdhklnrStUuvz] [-I length] [-i interval] [-O length]\n"
1.100 jeremy 975: "\t [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n"
1.98 guenther 976: "\t [-V rtable] [-w timeout] [-X proxy_protocol]\n"
1.100 jeremy 977: "\t [-x proxy_address[:port]] [destination] [port]\n");
1.21 ericj 978: if (ret)
979: exit(1);
1.7 deraadt 980: }
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