Annotation of src/usr.bin/nc/netcat.c, Revision 1.86
1.86 ! djm 1: /* $OpenBSD: netcat.c,v 1.85 2006/01/20 00:01:20 millert 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
1.31 ericj 65:
1.21 ericj 66: /* Command Line Options */
1.68 tedu 67: int dflag; /* detached, no stdin */
1.21 ericj 68: int iflag; /* Interval Flag */
1.80 mcbride 69: int jflag; /* use jumbo frames if we can */
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 */
1.65 markus 83: int Sflag; /* TCP MD5 signature option */
1.83 dtucker 84: int Tflag = -1; /* IP Type of Service */
1.21 ericj 85:
1.49 hugh 86: int timeout = -1;
1.21 ericj 87: int family = AF_UNSPEC;
1.63 miod 88: char *portlist[PORT_MAX+1];
1.21 ericj 89:
1.40 millert 90: void atelnet(int, unsigned char *, unsigned int);
91: void build_ports(char *);
92: void help(void);
93: int local_listen(char *, char *, struct addrinfo);
94: void readwrite(int);
1.77 otto 95: int remote_connect(const char *, const char *, struct addrinfo);
1.86 ! djm 96: int socks_connect(const char *, const char *, struct addrinfo,
! 97: const char *, const char *, struct addrinfo, int, const char *);
1.40 millert 98: int udptest(int);
1.42 ericj 99: int unix_connect(char *);
100: int unix_listen(char *);
1.84 dtucker 101: void set_common_sockopts(int);
1.83 dtucker 102: int parse_iptos(char *);
1.40 millert 103: void usage(int);
1.1 deraadt 104:
1.21 ericj 105: int
1.37 jakob 106: main(int argc, char *argv[])
1.21 ericj 107: {
1.46 markus 108: int ch, s, ret, socksv;
1.26 ericj 109: char *host, *uport, *endp;
1.21 ericj 110: struct addrinfo hints;
1.29 smart 111: struct servent *sv;
1.21 ericj 112: socklen_t len;
1.76 hshoexer 113: struct sockaddr_storage cliaddr;
1.34 jakob 114: char *proxy;
1.77 otto 115: const char *proxyhost = "", *proxyport = NULL;
1.34 jakob 116: struct addrinfo proxyhints;
1.11 ericj 117:
1.29 smart 118: ret = 1;
119: s = 0;
1.46 markus 120: socksv = 5;
1.29 smart 121: host = NULL;
122: uport = NULL;
123: endp = NULL;
124: sv = NULL;
125:
1.80 mcbride 126: while ((ch = getopt(argc, argv,
1.86 ! djm 127: "46Ddhi:jklnP:p:rSs:tT:Uuvw:X:x:z")) != -1) {
1.21 ericj 128: switch (ch) {
129: case '4':
130: family = AF_INET;
131: break;
132: case '6':
133: family = AF_INET6;
134: break;
1.42 ericj 135: case 'U':
136: family = AF_UNIX;
137: break;
1.46 markus 138: case 'X':
1.75 djm 139: if (strcasecmp(optarg, "connect") == 0)
140: socksv = -1; /* HTTP proxy CONNECT */
141: else if (strcmp(optarg, "4") == 0)
142: socksv = 4; /* SOCKS v.4 */
143: else if (strcmp(optarg, "5") == 0)
144: socksv = 5; /* SOCKS v.5 */
145: else
146: errx(1, "unsupported proxy protocol");
1.46 markus 147: break;
1.68 tedu 148: case 'd':
149: dflag = 1;
150: break;
1.21 ericj 151: case 'h':
152: help();
153: break;
154: case 'i':
1.26 ericj 155: iflag = (int)strtoul(optarg, &endp, 10);
156: if (iflag < 0 || *endp != '\0')
157: errx(1, "interval cannot be negative");
1.21 ericj 158: break;
1.80 mcbride 159: case 'j':
160: jflag = 1;
161: break;
1.21 ericj 162: case 'k':
163: kflag = 1;
164: break;
165: case 'l':
166: lflag = 1;
167: break;
168: case 'n':
169: nflag = 1;
170: break;
1.86 ! djm 171: case 'P':
! 172: Pflag = optarg;
! 173: break;
1.21 ericj 174: case 'p':
175: pflag = optarg;
176: break;
177: case 'r':
178: rflag = 1;
179: break;
180: case 's':
181: sflag = optarg;
182: break;
183: case 't':
184: tflag = 1;
185: break;
186: case 'u':
187: uflag = 1;
188: break;
189: case 'v':
190: vflag = 1;
191: break;
1.70 deraadt 192: case 'w':
1.26 ericj 193: timeout = (int)strtoul(optarg, &endp, 10);
194: if (timeout < 0 || *endp != '\0')
195: errx(1, "timeout cannot be negative");
1.49 hugh 196: if (timeout >= (INT_MAX / 1000))
197: errx(1, "timeout too large");
198: timeout *= 1000;
1.21 ericj 199: break;
1.34 jakob 200: case 'x':
201: xflag = 1;
1.64 deraadt 202: if ((proxy = strdup(optarg)) == NULL)
203: err(1, NULL);
1.34 jakob 204: break;
1.21 ericj 205: case 'z':
206: zflag = 1;
207: break;
1.73 markus 208: case 'D':
209: Dflag = 1;
210: break;
1.65 markus 211: case 'S':
212: Sflag = 1;
213: break;
1.83 dtucker 214: case 'T':
215: Tflag = parse_iptos(optarg);
216: break;
1.21 ericj 217: default:
218: usage(1);
219: }
220: }
221: argc -= optind;
222: argv += optind;
1.11 ericj 223:
1.21 ericj 224: /* Cruft to make sure options are clean, and used properly. */
1.42 ericj 225: if (argv[0] && !argv[1] && family == AF_UNIX) {
226: if (uflag)
227: errx(1, "cannot use -u and -U");
228: host = argv[0];
229: uport = NULL;
230: } else if (argv[0] && !argv[1]) {
1.21 ericj 231: if (!lflag)
232: usage(1);
233: uport = argv[0];
234: host = NULL;
235: } else if (argv[0] && argv[1]) {
236: host = argv[0];
237: uport = argv[1];
238: } else
239: usage(1);
1.1 deraadt 240:
1.21 ericj 241: if (lflag && sflag)
242: errx(1, "cannot use -s and -l");
243: if (lflag && pflag)
244: errx(1, "cannot use -p and -l");
245: if (lflag && zflag)
1.32 ericj 246: errx(1, "cannot use -z and -l");
1.21 ericj 247: if (!lflag && kflag)
1.32 ericj 248: errx(1, "must use -l with -k");
1.21 ericj 249:
1.67 jmc 250: /* Initialize addrinfo structure. */
1.42 ericj 251: if (family != AF_UNIX) {
252: memset(&hints, 0, sizeof(struct addrinfo));
253: hints.ai_family = family;
254: hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
255: hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
256: if (nflag)
257: hints.ai_flags |= AI_NUMERICHOST;
258: }
1.1 deraadt 259:
1.34 jakob 260: if (xflag) {
261: if (uflag)
262: errx(1, "no proxy support for UDP mode");
263:
264: if (lflag)
265: errx(1, "no proxy support for listen");
266:
1.42 ericj 267: if (family == AF_UNIX)
268: errx(1, "no proxy support for unix sockets");
269:
1.34 jakob 270: /* XXX IPv6 transport to proxy would probably work */
271: if (family == AF_INET6)
272: errx(1, "no proxy support for IPv6");
273:
274: if (sflag)
275: errx(1, "no proxy support for local source address");
276:
277: proxyhost = strsep(&proxy, ":");
278: proxyport = proxy;
279:
280: memset(&proxyhints, 0, sizeof(struct addrinfo));
281: proxyhints.ai_family = family;
282: proxyhints.ai_socktype = SOCK_STREAM;
283: proxyhints.ai_protocol = IPPROTO_TCP;
284: if (nflag)
285: proxyhints.ai_flags |= AI_NUMERICHOST;
286: }
287:
1.21 ericj 288: if (lflag) {
289: int connfd;
1.27 ericj 290: ret = 0;
1.1 deraadt 291:
1.42 ericj 292: if (family == AF_UNIX)
293: s = unix_listen(host);
294:
1.67 jmc 295: /* Allow only one connection at a time, but stay alive. */
1.21 ericj 296: for (;;) {
1.42 ericj 297: if (family != AF_UNIX)
298: s = local_listen(host, uport, hints);
299: if (s < 0)
1.30 smart 300: err(1, NULL);
1.21 ericj 301: /*
302: * For UDP, we will use recvfrom() initially
303: * to wait for a caller, then use the regular
304: * functions to talk to the caller.
305: */
306: if (uflag) {
1.80 mcbride 307: int rv, plen;
308: char buf[8192];
1.21 ericj 309: struct sockaddr_storage z;
310:
311: len = sizeof(z);
1.80 mcbride 312: plen = jflag ? 8192 : 1024;
313: rv = recvfrom(s, buf, plen, MSG_PEEK,
1.37 jakob 314: (struct sockaddr *)&z, &len);
1.23 ericj 315: if (rv < 0)
1.57 stevesk 316: err(1, "recvfrom");
1.21 ericj 317:
1.37 jakob 318: rv = connect(s, (struct sockaddr *)&z, len);
1.23 ericj 319: if (rv < 0)
1.57 stevesk 320: err(1, "connect");
1.1 deraadt 321:
1.21 ericj 322: connfd = s;
323: } else {
1.78 otto 324: len = sizeof(cliaddr);
1.21 ericj 325: connfd = accept(s, (struct sockaddr *)&cliaddr,
1.37 jakob 326: &len);
1.21 ericj 327: }
1.1 deraadt 328:
1.21 ericj 329: readwrite(connfd);
330: close(connfd);
1.42 ericj 331: if (family != AF_UNIX)
332: close(s);
1.27 ericj 333:
1.21 ericj 334: if (!kflag)
335: break;
1.11 ericj 336: }
1.42 ericj 337: } else if (family == AF_UNIX) {
338: ret = 0;
339:
340: if ((s = unix_connect(host)) > 0 && !zflag) {
341: readwrite(s);
342: close(s);
343: } else
344: ret = 1;
345:
346: exit(ret);
347:
1.21 ericj 348: } else {
349: int i = 0;
1.6 deraadt 350:
1.67 jmc 351: /* Construct the portlist[] array. */
1.21 ericj 352: build_ports(uport);
1.1 deraadt 353:
1.67 jmc 354: /* Cycle through portlist, connecting to each port. */
1.21 ericj 355: for (i = 0; portlist[i] != NULL; i++) {
356: if (s)
357: close(s);
1.34 jakob 358:
359: if (xflag)
360: s = socks_connect(host, portlist[i], hints,
1.86 ! djm 361: proxyhost, proxyport, proxyhints, socksv,
! 362: Pflag);
1.34 jakob 363: else
364: s = remote_connect(host, portlist[i], hints);
365:
366: if (s < 0)
1.21 ericj 367: continue;
1.1 deraadt 368:
1.21 ericj 369: ret = 0;
370: if (vflag || zflag) {
1.67 jmc 371: /* For UDP, make sure we are connected. */
1.21 ericj 372: if (uflag) {
1.50 vincent 373: if (udptest(s) == -1) {
1.21 ericj 374: ret = 1;
375: continue;
376: }
377: }
1.1 deraadt 378:
1.67 jmc 379: /* Don't look up port if -n. */
1.21 ericj 380: if (nflag)
381: sv = NULL;
382: else {
383: sv = getservbyport(
1.37 jakob 384: ntohs(atoi(portlist[i])),
385: uflag ? "udp" : "tcp");
1.21 ericj 386: }
1.50 vincent 387:
1.21 ericj 388: printf("Connection to %s %s port [%s/%s] succeeded!\n",
1.37 jakob 389: host, portlist[i], uflag ? "udp" : "tcp",
390: sv ? sv->s_name : "*");
1.21 ericj 391: }
392: if (!zflag)
393: readwrite(s);
1.7 deraadt 394: }
1.11 ericj 395: }
1.1 deraadt 396:
1.21 ericj 397: if (s)
398: close(s);
399:
400: exit(ret);
1.7 deraadt 401: }
1.1 deraadt 402:
1.11 ericj 403: /*
1.42 ericj 404: * unix_connect()
1.67 jmc 405: * Returns a socket connected to a local unix socket. Returns -1 on failure.
1.42 ericj 406: */
407: int
408: unix_connect(char *path)
409: {
410: struct sockaddr_un sun;
411: int s;
412:
413: if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
1.50 vincent 414: return (-1);
1.42 ericj 415: (void)fcntl(s, F_SETFD, 1);
416:
417: memset(&sun, 0, sizeof(struct sockaddr_un));
418: sun.sun_family = AF_UNIX;
1.60 avsm 419:
420: if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
421: sizeof(sun.sun_path)) {
422: close(s);
423: errno = ENAMETOOLONG;
424: return (-1);
425: }
1.50 vincent 426: if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
427: close(s);
428: return (-1);
1.42 ericj 429: }
430: return (s);
1.50 vincent 431:
1.42 ericj 432: }
433:
434: /*
435: * unix_listen()
1.67 jmc 436: * Create a unix domain socket, and listen on it.
1.42 ericj 437: */
438: int
439: unix_listen(char *path)
440: {
441: struct sockaddr_un sun;
442: int s;
443:
1.67 jmc 444: /* Create unix domain socket. */
1.42 ericj 445: if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
446: return (-1);
447:
1.60 avsm 448: memset(&sun, 0, sizeof(struct sockaddr_un));
1.42 ericj 449: sun.sun_family = AF_UNIX;
1.60 avsm 450:
451: if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
452: sizeof(sun.sun_path)) {
453: close(s);
454: errno = ENAMETOOLONG;
455: return (-1);
456: }
457:
1.50 vincent 458: if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
1.42 ericj 459: close(s);
460: return (-1);
461: }
462:
463: if (listen(s, 5) < 0) {
464: close(s);
465: return (-1);
466: }
467: return (s);
468: }
469:
470: /*
1.21 ericj 471: * remote_connect()
1.67 jmc 472: * Returns a socket connected to a remote host. Properly binds to a local
473: * port or source address if needed. Returns -1 on failure.
1.11 ericj 474: */
1.21 ericj 475: int
1.77 otto 476: remote_connect(const char *host, const char *port, struct addrinfo hints)
1.21 ericj 477: {
478: struct addrinfo *res, *res0;
1.81 marius 479: int s, error;
1.21 ericj 480:
481: if ((error = getaddrinfo(host, port, &hints, &res)))
1.56 stevesk 482: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.21 ericj 483:
484: res0 = res;
485: do {
486: if ((s = socket(res0->ai_family, res0->ai_socktype,
1.37 jakob 487: res0->ai_protocol)) < 0)
1.21 ericj 488: continue;
489:
1.67 jmc 490: /* Bind to a local port or source address if specified. */
1.21 ericj 491: if (sflag || pflag) {
492: struct addrinfo ahints, *ares;
493:
494: if (!(sflag && pflag)) {
495: if (!sflag)
496: sflag = NULL;
497: else
498: pflag = NULL;
499: }
1.6 deraadt 500:
1.21 ericj 501: memset(&ahints, 0, sizeof(struct addrinfo));
502: ahints.ai_family = res0->ai_family;
503: ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
504: ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
1.25 ericj 505: ahints.ai_flags = AI_PASSIVE;
1.38 jakob 506: if ((error = getaddrinfo(sflag, pflag, &ahints, &ares)))
1.56 stevesk 507: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.21 ericj 508:
509: if (bind(s, (struct sockaddr *)ares->ai_addr,
1.62 millert 510: ares->ai_addrlen) < 0)
1.21 ericj 511: errx(1, "bind failed: %s", strerror(errno));
512: freeaddrinfo(ares);
1.6 deraadt 513: }
1.81 marius 514:
515: set_common_sockopts(s);
1.6 deraadt 516:
1.21 ericj 517: if (connect(s, res0->ai_addr, res0->ai_addrlen) == 0)
1.6 deraadt 518: break;
1.71 mcbride 519: else if (vflag)
520: warn("connect to %s port %s (%s) failed", host, port,
521: uflag ? "udp" : "tcp");
1.34 jakob 522:
1.21 ericj 523: close(s);
524: s = -1;
525: } while ((res0 = res0->ai_next) != NULL);
526:
527: freeaddrinfo(res);
1.1 deraadt 528:
1.21 ericj 529: return (s);
1.7 deraadt 530: }
1.1 deraadt 531:
1.11 ericj 532: /*
1.21 ericj 533: * local_listen()
1.67 jmc 534: * Returns a socket listening on a local port, binds to specified source
535: * address. Returns -1 on failure.
1.11 ericj 536: */
1.21 ericj 537: int
1.37 jakob 538: local_listen(char *host, char *port, struct addrinfo hints)
1.21 ericj 539: {
540: struct addrinfo *res, *res0;
541: int s, ret, x = 1;
542: int error;
1.6 deraadt 543:
1.67 jmc 544: /* Allow nodename to be null. */
1.21 ericj 545: hints.ai_flags |= AI_PASSIVE;
1.7 deraadt 546:
1.21 ericj 547: /*
548: * In the case of binding to a wildcard address
549: * default to binding to an ipv4 address.
550: */
551: if (host == NULL && hints.ai_family == AF_UNSPEC)
552: hints.ai_family = AF_INET;
1.1 deraadt 553:
1.21 ericj 554: if ((error = getaddrinfo(host, port, &hints, &res)))
1.70 deraadt 555: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.14 ericj 556:
1.21 ericj 557: res0 = res;
558: do {
559: if ((s = socket(res0->ai_family, res0->ai_socktype,
1.82 marius 560: res0->ai_protocol)) < 0)
1.21 ericj 561: continue;
1.1 deraadt 562:
1.21 ericj 563: ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x));
564: if (ret == -1)
1.30 smart 565: err(1, NULL);
1.81 marius 566:
567: set_common_sockopts(s);
1.1 deraadt 568:
1.21 ericj 569: if (bind(s, (struct sockaddr *)res0->ai_addr,
1.37 jakob 570: res0->ai_addrlen) == 0)
1.21 ericj 571: break;
1.1 deraadt 572:
1.21 ericj 573: close(s);
574: s = -1;
575: } while ((res0 = res0->ai_next) != NULL);
1.1 deraadt 576:
1.47 ericj 577: if (!uflag && s != -1) {
1.21 ericj 578: if (listen(s, 1) < 0)
1.57 stevesk 579: err(1, "listen");
1.12 ericj 580: }
1.1 deraadt 581:
1.21 ericj 582: freeaddrinfo(res);
1.1 deraadt 583:
1.21 ericj 584: return (s);
1.7 deraadt 585: }
586:
1.11 ericj 587: /*
1.21 ericj 588: * readwrite()
589: * Loop that polls on the network file descriptor and stdin.
1.11 ericj 590: */
1.21 ericj 591: void
1.37 jakob 592: readwrite(int nfd)
1.6 deraadt 593: {
1.52 vincent 594: struct pollfd pfd[2];
1.80 mcbride 595: unsigned char buf[8192];
1.79 avsm 596: int n, wfd = fileno(stdin);
1.21 ericj 597: int lfd = fileno(stdout);
1.80 mcbride 598: int plen;
599:
600: plen = jflag ? 8192 : 1024;
1.21 ericj 601:
602: /* Setup Network FD */
603: pfd[0].fd = nfd;
604: pfd[0].events = POLLIN;
605:
1.67 jmc 606: /* Set up STDIN FD. */
1.21 ericj 607: pfd[1].fd = wfd;
608: pfd[1].events = POLLIN;
609:
1.54 aaron 610: while (pfd[0].fd != -1) {
1.21 ericj 611: if (iflag)
612: sleep(iflag);
613:
1.68 tedu 614: if ((n = poll(pfd, 2 - dflag, timeout)) < 0) {
1.21 ericj 615: close(nfd);
1.52 vincent 616: err(1, "Polling Error");
1.21 ericj 617: }
1.49 hugh 618:
619: if (n == 0)
620: return;
1.21 ericj 621:
622: if (pfd[0].revents & POLLIN) {
1.80 mcbride 623: if ((n = read(nfd, buf, plen)) < 0)
1.21 ericj 624: return;
1.52 vincent 625: else if (n == 0) {
626: shutdown(nfd, SHUT_RD);
627: pfd[0].fd = -1;
628: pfd[0].events = 0;
1.21 ericj 629: } else {
630: if (tflag)
631: atelnet(nfd, buf, n);
1.79 avsm 632: if (atomicio(vwrite, lfd, buf, n) != n)
1.21 ericj 633: return;
1.6 deraadt 634: }
1.21 ericj 635: }
636:
1.68 tedu 637: if (!dflag && pfd[1].revents & POLLIN) {
1.80 mcbride 638: if ((n = read(wfd, buf, plen)) < 0)
1.21 ericj 639: return;
1.52 vincent 640: else if (n == 0) {
641: shutdown(nfd, SHUT_WR);
642: pfd[1].fd = -1;
643: pfd[1].events = 0;
644: } else {
1.79 avsm 645: if (atomicio(vwrite, nfd, buf, n) != n)
1.21 ericj 646: return;
1.50 vincent 647: }
1.21 ericj 648: }
1.11 ericj 649: }
1.7 deraadt 650: }
1.50 vincent 651:
1.67 jmc 652: /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */
1.21 ericj 653: void
1.37 jakob 654: atelnet(int nfd, unsigned char *buf, unsigned int size)
1.6 deraadt 655: {
1.24 ericj 656: unsigned char *p, *end;
657: unsigned char obuf[4];
658:
659: end = buf + size;
660: obuf[0] = '\0';
661:
662: for (p = buf; p < end; p++) {
1.21 ericj 663: if (*p != IAC)
1.24 ericj 664: break;
665:
1.25 ericj 666: obuf[0] = IAC;
1.24 ericj 667: p++;
1.50 vincent 668: if ((*p == WILL) || (*p == WONT))
1.24 ericj 669: obuf[1] = DONT;
1.50 vincent 670: if ((*p == DO) || (*p == DONT))
1.24 ericj 671: obuf[1] = WONT;
672: if (obuf) {
673: p++;
1.11 ericj 674: obuf[2] = *p;
1.24 ericj 675: obuf[3] = '\0';
1.79 avsm 676: if (atomicio(vwrite, nfd, obuf, 3) != 3)
677: warn("Write Error!");
1.24 ericj 678: obuf[0] = '\0';
1.11 ericj 679: }
680: }
1.7 deraadt 681: }
682:
1.11 ericj 683: /*
1.21 ericj 684: * build_ports()
685: * Build an array or ports in portlist[], listing each port
1.67 jmc 686: * that we should try to connect to.
1.11 ericj 687: */
1.21 ericj 688: void
1.37 jakob 689: build_ports(char *p)
1.6 deraadt 690: {
1.26 ericj 691: char *n, *endp;
1.21 ericj 692: int hi, lo, cp;
693: int x = 0;
694:
695: if ((n = strchr(p, '-')) != NULL) {
696: if (lflag)
697: errx(1, "Cannot use -l with multiple ports!");
698:
699: *n = '\0';
700: n++;
701:
1.67 jmc 702: /* Make sure the ports are in order: lowest->highest. */
1.26 ericj 703: hi = (int)strtoul(n, &endp, 10);
1.31 ericj 704: if (hi <= 0 || hi > PORT_MAX || *endp != '\0')
1.26 ericj 705: errx(1, "port range not valid");
706: lo = (int)strtoul(p, &endp, 10);
1.31 ericj 707: if (lo <= 0 || lo > PORT_MAX || *endp != '\0')
1.26 ericj 708: errx(1, "port range not valid");
1.21 ericj 709:
710: if (lo > hi) {
711: cp = hi;
712: hi = lo;
713: lo = cp;
714: }
715:
1.67 jmc 716: /* Load ports sequentially. */
1.21 ericj 717: for (cp = lo; cp <= hi; cp++) {
1.55 fgsch 718: portlist[x] = calloc(1, PORT_MAX_LEN);
719: if (portlist[x] == NULL)
720: err(1, NULL);
721: snprintf(portlist[x], PORT_MAX_LEN, "%d", cp);
1.21 ericj 722: x++;
723: }
724:
1.67 jmc 725: /* Randomly swap ports. */
1.21 ericj 726: if (rflag) {
727: int y;
728: char *c;
729:
730: for (x = 0; x <= (hi - lo); x++) {
731: y = (arc4random() & 0xFFFF) % (hi - lo);
732: c = portlist[x];
733: portlist[x] = portlist[y];
734: portlist[y] = c;
1.6 deraadt 735: }
1.11 ericj 736: }
1.21 ericj 737: } else {
1.26 ericj 738: hi = (int)strtoul(p, &endp, 10);
1.31 ericj 739: if (hi <= 0 || hi > PORT_MAX || *endp != '\0')
1.26 ericj 740: errx(1, "port range not valid");
1.55 fgsch 741: portlist[0] = calloc(1, PORT_MAX_LEN);
742: if (portlist[0] == NULL)
743: err(1, NULL);
1.21 ericj 744: portlist[0] = p;
1.11 ericj 745: }
1.13 ericj 746: }
747:
748: /*
1.21 ericj 749: * udptest()
750: * Do a few writes to see if the UDP port is there.
1.67 jmc 751: * XXX - Better way of doing this? Doesn't work for IPv6.
1.21 ericj 752: * Also fails after around 100 ports checked.
1.13 ericj 753: */
1.21 ericj 754: int
1.37 jakob 755: udptest(int s)
1.13 ericj 756: {
1.74 deraadt 757: int i, ret;
1.13 ericj 758:
1.52 vincent 759: for (i = 0; i <= 3; i++) {
1.74 deraadt 760: if (write(s, "X", 1) == 1)
1.21 ericj 761: ret = 1;
1.14 ericj 762: else
1.21 ericj 763: ret = -1;
1.14 ericj 764: }
1.21 ericj 765: return (ret);
1.81 marius 766: }
767:
1.84 dtucker 768: void
1.81 marius 769: set_common_sockopts(int s)
770: {
771: int x = 1;
772:
773: if (Sflag) {
774: if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
775: &x, sizeof(x)) == -1)
776: err(1, NULL);
777: }
778: if (Dflag) {
779: if (setsockopt(s, SOL_SOCKET, SO_DEBUG,
780: &x, sizeof(x)) == -1)
781: err(1, NULL);
782: }
783: if (jflag) {
784: if (setsockopt(s, SOL_SOCKET, SO_JUMBO,
785: &x, sizeof(x)) == -1)
786: err(1, NULL);
787: }
1.83 dtucker 788: if (Tflag != -1) {
789: if (setsockopt(s, IPPROTO_IP, IP_TOS,
790: &Tflag, sizeof(Tflag)) == -1)
791: err(1, "set IP ToS");
792: }
793: }
794:
795: int
796: parse_iptos(char *s)
797: {
798: int tos = -1;
799:
800: if (strcmp(s, "lowdelay") == 0)
801: return (IPTOS_LOWDELAY);
802: if (strcmp(s, "throughput") == 0)
803: return (IPTOS_THROUGHPUT);
804: if (strcmp(s, "reliability") == 0)
805: return (IPTOS_RELIABILITY);
806:
807: if (sscanf(s, "0x%x", &tos) != 1 || tos < 0 || tos > 0xff)
808: errx(1, "invalid IP Type of Service");
809: return (tos);
1.7 deraadt 810: }
1.1 deraadt 811:
1.11 ericj 812: void
1.58 deraadt 813: help(void)
1.1 deraadt 814: {
1.21 ericj 815: usage(0);
816: fprintf(stderr, "\tCommand Summary:\n\
817: \t-4 Use IPv4\n\
818: \t-6 Use IPv6\n\
1.73 markus 819: \t-D Enable the debug socket option\n\
1.69 tedu 820: \t-d Detach from stdin\n\
1.21 ericj 821: \t-h This help text\n\
822: \t-i secs\t Delay interval for lines sent, ports scanned\n\
823: \t-k Keep inbound sockets open for multiple connects\n\
824: \t-l Listen mode, for inbound connects\n\
1.22 jasoni 825: \t-n Suppress name/port resolutions\n\
1.86 ! djm 826: \t-P proxyuser\tUsername for proxy authentication\n\
1.36 jakob 827: \t-p port\t Specify local port for remote connects\n\
1.21 ericj 828: \t-r Randomize remote ports\n\
1.67 jmc 829: \t-S Enable the TCP MD5 signature option\n\
1.21 ericj 830: \t-s addr\t Local source address\n\
1.83 dtucker 831: \t-T ToS\t Set IP Type of Service\n\
1.21 ericj 832: \t-t Answer TELNET negotiation\n\
1.67 jmc 833: \t-U Use UNIX domain socket\n\
1.21 ericj 834: \t-u UDP mode\n\
835: \t-v Verbose\n\
836: \t-w secs\t Timeout for connects and final net reads\n\
1.75 djm 837: \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\
838: \t-x addr[:port]\tSpecify proxy address and port\n\
1.21 ericj 839: \t-z Zero-I/O mode [used for scanning]\n\
840: Port numbers can be individual or ranges: lo-hi [inclusive]\n");
841: exit(1);
1.11 ericj 842: }
843:
844: void
1.37 jakob 845: usage(int ret)
1.11 ericj 846: {
1.73 markus 847: fprintf(stderr, "usage: nc [-46DdhklnrStUuvz] [-i interval] [-p source_port]\n");
1.83 dtucker 848: fprintf(stderr, "\t [-s source_ip_address] [-T ToS] [-w timeout] [-X proxy_version]\n");
1.72 jmc 849: fprintf(stderr, "\t [-x proxy_address[:port]] [hostname] [port[s]]\n");
1.21 ericj 850: if (ret)
851: exit(1);
1.7 deraadt 852: }
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