Annotation of src/usr.bin/nc/netcat.c, Revision 1.109
1.109 ! haesbaer 1: /* $OpenBSD: netcat.c,v 1.108 2012/07/07 09:36:30 haesbaert 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: /*
1.109 ! haesbaer 348: * For UDP and -k, don't connect the socket, let it
! 349: * receive datagrams from multiple socket pairs.
1.21 ericj 350: */
1.109 ! haesbaer 351: if (uflag && kflag)
! 352: readwrite(s);
! 353: /*
! 354: * For UDP and not -k, we will use recvfrom() initially
! 355: * to wait for a caller, then use the regular functions
! 356: * to talk to the caller.
! 357: */
! 358: else if (uflag && !kflag) {
1.80 mcbride 359: int rv, plen;
1.97 nicm 360: char buf[16384];
1.21 ericj 361: struct sockaddr_storage z;
362:
363: len = sizeof(z);
1.106 dlg 364: plen = 2048;
1.80 mcbride 365: rv = recvfrom(s, buf, plen, MSG_PEEK,
1.37 jakob 366: (struct sockaddr *)&z, &len);
1.23 ericj 367: if (rv < 0)
1.57 stevesk 368: err(1, "recvfrom");
1.21 ericj 369:
1.37 jakob 370: rv = connect(s, (struct sockaddr *)&z, len);
1.23 ericj 371: if (rv < 0)
1.57 stevesk 372: err(1, "connect");
1.1 deraadt 373:
1.108 haesbaer 374: if (vflag)
375: report_connect((struct sockaddr *)&z, len);
376:
1.99 jeremy 377: readwrite(s);
1.21 ericj 378: } else {
1.78 otto 379: len = sizeof(cliaddr);
1.21 ericj 380: connfd = accept(s, (struct sockaddr *)&cliaddr,
1.37 jakob 381: &len);
1.107 deraadt 382: if (connfd == -1)
383: err(1, "accept");
1.108 haesbaer 384:
385: if (vflag)
386: report_connect((struct sockaddr *)&cliaddr, len);
387:
1.99 jeremy 388: readwrite(connfd);
389: close(connfd);
1.21 ericj 390: }
1.1 deraadt 391:
1.42 ericj 392: if (family != AF_UNIX)
393: close(s);
1.99 jeremy 394: else if (uflag) {
395: if (connect(s, NULL, 0) < 0)
396: err(1, "connect");
397: }
1.27 ericj 398:
1.21 ericj 399: if (!kflag)
400: break;
1.11 ericj 401: }
1.42 ericj 402: } else if (family == AF_UNIX) {
403: ret = 0;
404:
405: if ((s = unix_connect(host)) > 0 && !zflag) {
406: readwrite(s);
407: close(s);
408: } else
409: ret = 1;
410:
1.99 jeremy 411: if (uflag)
412: unlink(unix_dg_tmp_socket);
1.42 ericj 413: exit(ret);
414:
1.21 ericj 415: } else {
416: int i = 0;
1.6 deraadt 417:
1.67 jmc 418: /* Construct the portlist[] array. */
1.21 ericj 419: build_ports(uport);
1.1 deraadt 420:
1.67 jmc 421: /* Cycle through portlist, connecting to each port. */
1.21 ericj 422: for (i = 0; portlist[i] != NULL; i++) {
423: if (s)
424: close(s);
1.34 jakob 425:
426: if (xflag)
427: s = socks_connect(host, portlist[i], hints,
1.86 djm 428: proxyhost, proxyport, proxyhints, socksv,
429: Pflag);
1.34 jakob 430: else
431: s = remote_connect(host, portlist[i], hints);
432:
433: if (s < 0)
1.21 ericj 434: continue;
1.1 deraadt 435:
1.21 ericj 436: ret = 0;
437: if (vflag || zflag) {
1.67 jmc 438: /* For UDP, make sure we are connected. */
1.21 ericj 439: if (uflag) {
1.50 vincent 440: if (udptest(s) == -1) {
1.21 ericj 441: ret = 1;
442: continue;
443: }
444: }
1.1 deraadt 445:
1.67 jmc 446: /* Don't look up port if -n. */
1.21 ericj 447: if (nflag)
448: sv = NULL;
449: else {
450: sv = getservbyport(
1.37 jakob 451: ntohs(atoi(portlist[i])),
452: uflag ? "udp" : "tcp");
1.21 ericj 453: }
1.50 vincent 454:
1.94 mpf 455: fprintf(stderr,
456: "Connection to %s %s port [%s/%s] "
457: "succeeded!\n", host, portlist[i],
458: uflag ? "udp" : "tcp",
1.37 jakob 459: sv ? sv->s_name : "*");
1.21 ericj 460: }
461: if (!zflag)
462: readwrite(s);
1.7 deraadt 463: }
1.11 ericj 464: }
1.1 deraadt 465:
1.21 ericj 466: if (s)
467: close(s);
468:
469: exit(ret);
1.7 deraadt 470: }
1.1 deraadt 471:
1.11 ericj 472: /*
1.99 jeremy 473: * unix_bind()
474: * Returns a unix socket bound to the given path
1.42 ericj 475: */
476: int
1.99 jeremy 477: unix_bind(char *path)
1.42 ericj 478: {
479: struct sockaddr_un sun;
480: int s;
481:
1.99 jeremy 482: /* Create unix domain socket. */
483: if ((s = socket(AF_UNIX, uflag ? SOCK_DGRAM : SOCK_STREAM,
484: 0)) < 0)
1.50 vincent 485: return (-1);
1.42 ericj 486:
487: memset(&sun, 0, sizeof(struct sockaddr_un));
488: sun.sun_family = AF_UNIX;
1.60 avsm 489:
490: if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
491: sizeof(sun.sun_path)) {
492: close(s);
493: errno = ENAMETOOLONG;
494: return (-1);
495: }
1.99 jeremy 496:
497: if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
1.50 vincent 498: close(s);
499: return (-1);
1.42 ericj 500: }
501: return (s);
502: }
503:
504: /*
1.99 jeremy 505: * unix_connect()
506: * Returns a socket connected to a local unix socket. Returns -1 on failure.
1.42 ericj 507: */
508: int
1.99 jeremy 509: unix_connect(char *path)
1.42 ericj 510: {
511: struct sockaddr_un sun;
512: int s;
513:
1.99 jeremy 514: if (uflag) {
515: if ((s = unix_bind(unix_dg_tmp_socket)) < 0)
516: return (-1);
517: } else {
518: if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
519: return (-1);
520: }
521: (void)fcntl(s, F_SETFD, 1);
1.42 ericj 522:
1.60 avsm 523: memset(&sun, 0, sizeof(struct sockaddr_un));
1.42 ericj 524: sun.sun_family = AF_UNIX;
1.60 avsm 525:
526: if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
527: sizeof(sun.sun_path)) {
528: close(s);
529: errno = ENAMETOOLONG;
530: return (-1);
531: }
1.99 jeremy 532: if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
1.42 ericj 533: close(s);
534: return (-1);
535: }
1.99 jeremy 536: return (s);
537:
538: }
539:
540: /*
541: * unix_listen()
542: * Create a unix domain socket, and listen on it.
543: */
544: int
545: unix_listen(char *path)
546: {
547: int s;
548: if ((s = unix_bind(path)) < 0)
549: return (-1);
1.42 ericj 550:
551: if (listen(s, 5) < 0) {
552: close(s);
553: return (-1);
554: }
555: return (s);
556: }
557:
558: /*
1.21 ericj 559: * remote_connect()
1.67 jmc 560: * Returns a socket connected to a remote host. Properly binds to a local
561: * port or source address if needed. Returns -1 on failure.
1.11 ericj 562: */
1.21 ericj 563: int
1.77 otto 564: remote_connect(const char *host, const char *port, struct addrinfo hints)
1.21 ericj 565: {
566: struct addrinfo *res, *res0;
1.91 markus 567: int s, error, on = 1;
1.21 ericj 568:
569: if ((error = getaddrinfo(host, port, &hints, &res)))
1.56 stevesk 570: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.21 ericj 571:
572: res0 = res;
573: do {
574: if ((s = socket(res0->ai_family, res0->ai_socktype,
1.37 jakob 575: res0->ai_protocol)) < 0)
1.21 ericj 576: continue;
577:
1.98 guenther 578: if (rtableid) {
1.101 mikeb 579: if (setsockopt(s, SOL_SOCKET, SO_RTABLE, &rtableid,
1.98 guenther 580: sizeof(rtableid)) == -1)
581: err(1, "setsockopt SO_RTABLE");
1.93 claudio 582: }
583:
1.67 jmc 584: /* Bind to a local port or source address if specified. */
1.21 ericj 585: if (sflag || pflag) {
586: struct addrinfo ahints, *ares;
1.6 deraadt 587:
1.91 markus 588: /* try SO_BINDANY, but don't insist */
589: setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on));
1.21 ericj 590: memset(&ahints, 0, sizeof(struct addrinfo));
591: ahints.ai_family = res0->ai_family;
592: ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
593: ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
1.25 ericj 594: ahints.ai_flags = AI_PASSIVE;
1.38 jakob 595: if ((error = getaddrinfo(sflag, pflag, &ahints, &ares)))
1.56 stevesk 596: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.21 ericj 597:
598: if (bind(s, (struct sockaddr *)ares->ai_addr,
1.62 millert 599: ares->ai_addrlen) < 0)
1.21 ericj 600: errx(1, "bind failed: %s", strerror(errno));
601: freeaddrinfo(ares);
1.6 deraadt 602: }
1.81 marius 603:
604: set_common_sockopts(s);
1.6 deraadt 605:
1.103 fgsch 606: if (timeout_connect(s, res0->ai_addr, res0->ai_addrlen) == 0)
1.6 deraadt 607: break;
1.71 mcbride 608: else if (vflag)
609: warn("connect to %s port %s (%s) failed", host, port,
610: uflag ? "udp" : "tcp");
1.34 jakob 611:
1.21 ericj 612: close(s);
613: s = -1;
614: } while ((res0 = res0->ai_next) != NULL);
615:
616: freeaddrinfo(res);
1.1 deraadt 617:
1.21 ericj 618: return (s);
1.103 fgsch 619: }
620:
621: int
622: timeout_connect(int s, const struct sockaddr *name, socklen_t namelen)
623: {
624: struct pollfd pfd;
625: socklen_t optlen;
626: int flags, optval;
627: int ret;
628:
629: if (timeout != -1) {
630: flags = fcntl(s, F_GETFL, 0);
631: if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1)
632: err(1, "set non-blocking mode");
633: }
634:
635: if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) {
636: pfd.fd = s;
637: pfd.events = POLLOUT;
638: if ((ret = poll(&pfd, 1, timeout)) == 1) {
639: optlen = sizeof(optval);
640: if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR,
641: &optval, &optlen)) == 0) {
642: errno = optval;
643: ret = optval == 0 ? 0 : -1;
644: }
645: } else if (ret == 0) {
646: errno = ETIMEDOUT;
647: ret = -1;
648: } else
649: err(1, "poll failed");
650: }
651:
652: if (timeout != -1 && fcntl(s, F_SETFL, flags) == -1)
653: err(1, "restoring flags");
654:
655: return (ret);
1.7 deraadt 656: }
1.1 deraadt 657:
1.11 ericj 658: /*
1.21 ericj 659: * local_listen()
1.67 jmc 660: * Returns a socket listening on a local port, binds to specified source
661: * address. Returns -1 on failure.
1.11 ericj 662: */
1.21 ericj 663: int
1.37 jakob 664: local_listen(char *host, char *port, struct addrinfo hints)
1.21 ericj 665: {
666: struct addrinfo *res, *res0;
667: int s, ret, x = 1;
668: int error;
1.6 deraadt 669:
1.67 jmc 670: /* Allow nodename to be null. */
1.21 ericj 671: hints.ai_flags |= AI_PASSIVE;
1.7 deraadt 672:
1.21 ericj 673: /*
674: * In the case of binding to a wildcard address
675: * default to binding to an ipv4 address.
676: */
677: if (host == NULL && hints.ai_family == AF_UNSPEC)
678: hints.ai_family = AF_INET;
1.1 deraadt 679:
1.21 ericj 680: if ((error = getaddrinfo(host, port, &hints, &res)))
1.70 deraadt 681: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.14 ericj 682:
1.21 ericj 683: res0 = res;
684: do {
685: if ((s = socket(res0->ai_family, res0->ai_socktype,
1.82 marius 686: res0->ai_protocol)) < 0)
1.21 ericj 687: continue;
1.1 deraadt 688:
1.98 guenther 689: if (rtableid) {
690: if (setsockopt(s, IPPROTO_IP, SO_RTABLE, &rtableid,
691: sizeof(rtableid)) == -1)
692: err(1, "setsockopt SO_RTABLE");
1.93 claudio 693: }
694:
1.21 ericj 695: ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x));
696: if (ret == -1)
1.30 smart 697: err(1, NULL);
1.81 marius 698:
699: set_common_sockopts(s);
1.1 deraadt 700:
1.21 ericj 701: if (bind(s, (struct sockaddr *)res0->ai_addr,
1.37 jakob 702: res0->ai_addrlen) == 0)
1.21 ericj 703: break;
1.1 deraadt 704:
1.21 ericj 705: close(s);
706: s = -1;
707: } while ((res0 = res0->ai_next) != NULL);
1.1 deraadt 708:
1.47 ericj 709: if (!uflag && s != -1) {
1.21 ericj 710: if (listen(s, 1) < 0)
1.57 stevesk 711: err(1, "listen");
1.12 ericj 712: }
1.1 deraadt 713:
1.21 ericj 714: freeaddrinfo(res);
1.1 deraadt 715:
1.21 ericj 716: return (s);
1.7 deraadt 717: }
718:
1.11 ericj 719: /*
1.21 ericj 720: * readwrite()
721: * Loop that polls on the network file descriptor and stdin.
1.11 ericj 722: */
1.21 ericj 723: void
1.37 jakob 724: readwrite(int nfd)
1.6 deraadt 725: {
1.52 vincent 726: struct pollfd pfd[2];
1.97 nicm 727: unsigned char buf[16384];
1.79 avsm 728: int n, wfd = fileno(stdin);
1.21 ericj 729: int lfd = fileno(stdout);
1.80 mcbride 730: int plen;
731:
1.106 dlg 732: plen = 2048;
1.21 ericj 733:
734: /* Setup Network FD */
735: pfd[0].fd = nfd;
736: pfd[0].events = POLLIN;
737:
1.67 jmc 738: /* Set up STDIN FD. */
1.21 ericj 739: pfd[1].fd = wfd;
740: pfd[1].events = POLLIN;
741:
1.54 aaron 742: while (pfd[0].fd != -1) {
1.21 ericj 743: if (iflag)
744: sleep(iflag);
745:
1.68 tedu 746: if ((n = poll(pfd, 2 - dflag, timeout)) < 0) {
1.21 ericj 747: close(nfd);
1.52 vincent 748: err(1, "Polling Error");
1.21 ericj 749: }
1.49 hugh 750:
751: if (n == 0)
752: return;
1.21 ericj 753:
754: if (pfd[0].revents & POLLIN) {
1.80 mcbride 755: if ((n = read(nfd, buf, plen)) < 0)
1.21 ericj 756: return;
1.52 vincent 757: else if (n == 0) {
758: shutdown(nfd, SHUT_RD);
759: pfd[0].fd = -1;
760: pfd[0].events = 0;
1.21 ericj 761: } else {
762: if (tflag)
763: atelnet(nfd, buf, n);
1.79 avsm 764: if (atomicio(vwrite, lfd, buf, n) != n)
1.21 ericj 765: return;
1.6 deraadt 766: }
1.21 ericj 767: }
768:
1.68 tedu 769: if (!dflag && pfd[1].revents & POLLIN) {
1.80 mcbride 770: if ((n = read(wfd, buf, plen)) < 0)
1.21 ericj 771: return;
1.52 vincent 772: else if (n == 0) {
773: shutdown(nfd, SHUT_WR);
774: pfd[1].fd = -1;
775: pfd[1].events = 0;
776: } else {
1.79 avsm 777: if (atomicio(vwrite, nfd, buf, n) != n)
1.21 ericj 778: return;
1.50 vincent 779: }
1.21 ericj 780: }
1.11 ericj 781: }
1.7 deraadt 782: }
1.50 vincent 783:
1.67 jmc 784: /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */
1.21 ericj 785: void
1.37 jakob 786: atelnet(int nfd, unsigned char *buf, unsigned int size)
1.6 deraadt 787: {
1.24 ericj 788: unsigned char *p, *end;
789: unsigned char obuf[4];
790:
1.95 nicm 791: if (size < 3)
792: return;
793: end = buf + size - 2;
1.24 ericj 794:
795: for (p = buf; p < end; p++) {
1.21 ericj 796: if (*p != IAC)
1.95 nicm 797: continue;
1.24 ericj 798:
1.25 ericj 799: obuf[0] = IAC;
1.24 ericj 800: p++;
1.50 vincent 801: if ((*p == WILL) || (*p == WONT))
1.24 ericj 802: obuf[1] = DONT;
1.95 nicm 803: else if ((*p == DO) || (*p == DONT))
1.24 ericj 804: obuf[1] = WONT;
1.95 nicm 805: else
806: continue;
807:
808: p++;
809: obuf[2] = *p;
810: if (atomicio(vwrite, nfd, obuf, 3) != 3)
811: warn("Write Error!");
1.11 ericj 812: }
1.7 deraadt 813: }
814:
1.11 ericj 815: /*
1.21 ericj 816: * build_ports()
1.105 lum 817: * Build an array of ports in portlist[], listing each port
1.67 jmc 818: * that we should try to connect to.
1.11 ericj 819: */
1.21 ericj 820: void
1.37 jakob 821: build_ports(char *p)
1.6 deraadt 822: {
1.88 ray 823: const char *errstr;
824: char *n;
1.21 ericj 825: int hi, lo, cp;
826: int x = 0;
827:
828: if ((n = strchr(p, '-')) != NULL) {
829: *n = '\0';
830: n++;
831:
1.67 jmc 832: /* Make sure the ports are in order: lowest->highest. */
1.88 ray 833: hi = strtonum(n, 1, PORT_MAX, &errstr);
834: if (errstr)
835: errx(1, "port number %s: %s", errstr, n);
836: lo = strtonum(p, 1, PORT_MAX, &errstr);
837: if (errstr)
838: errx(1, "port number %s: %s", errstr, p);
1.21 ericj 839:
840: if (lo > hi) {
841: cp = hi;
842: hi = lo;
843: lo = cp;
844: }
845:
1.67 jmc 846: /* Load ports sequentially. */
1.21 ericj 847: for (cp = lo; cp <= hi; cp++) {
1.55 fgsch 848: portlist[x] = calloc(1, PORT_MAX_LEN);
849: if (portlist[x] == NULL)
850: err(1, NULL);
851: snprintf(portlist[x], PORT_MAX_LEN, "%d", cp);
1.21 ericj 852: x++;
853: }
854:
1.67 jmc 855: /* Randomly swap ports. */
1.21 ericj 856: if (rflag) {
857: int y;
858: char *c;
859:
860: for (x = 0; x <= (hi - lo); x++) {
861: y = (arc4random() & 0xFFFF) % (hi - lo);
862: c = portlist[x];
863: portlist[x] = portlist[y];
864: portlist[y] = c;
1.6 deraadt 865: }
1.11 ericj 866: }
1.21 ericj 867: } else {
1.88 ray 868: hi = strtonum(p, 1, PORT_MAX, &errstr);
869: if (errstr)
870: errx(1, "port number %s: %s", errstr, p);
1.96 nicm 871: portlist[0] = strdup(p);
1.55 fgsch 872: if (portlist[0] == NULL)
873: err(1, NULL);
1.11 ericj 874: }
1.13 ericj 875: }
876:
877: /*
1.21 ericj 878: * udptest()
879: * Do a few writes to see if the UDP port is there.
1.105 lum 880: * Fails once PF state table is full.
1.13 ericj 881: */
1.21 ericj 882: int
1.37 jakob 883: udptest(int s)
1.13 ericj 884: {
1.74 deraadt 885: int i, ret;
1.13 ericj 886:
1.52 vincent 887: for (i = 0; i <= 3; i++) {
1.74 deraadt 888: if (write(s, "X", 1) == 1)
1.21 ericj 889: ret = 1;
1.14 ericj 890: else
1.21 ericj 891: ret = -1;
1.14 ericj 892: }
1.21 ericj 893: return (ret);
1.81 marius 894: }
895:
1.84 dtucker 896: void
1.81 marius 897: set_common_sockopts(int s)
898: {
899: int x = 1;
900:
901: if (Sflag) {
902: if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
903: &x, sizeof(x)) == -1)
904: err(1, NULL);
905: }
906: if (Dflag) {
907: if (setsockopt(s, SOL_SOCKET, SO_DEBUG,
908: &x, sizeof(x)) == -1)
909: err(1, NULL);
910: }
1.83 dtucker 911: if (Tflag != -1) {
912: if (setsockopt(s, IPPROTO_IP, IP_TOS,
913: &Tflag, sizeof(Tflag)) == -1)
914: err(1, "set IP ToS");
915: }
1.90 djm 916: if (Iflag) {
917: if (setsockopt(s, SOL_SOCKET, SO_RCVBUF,
918: &Iflag, sizeof(Iflag)) == -1)
919: err(1, "set TCP receive buffer size");
920: }
921: if (Oflag) {
922: if (setsockopt(s, SOL_SOCKET, SO_SNDBUF,
923: &Oflag, sizeof(Oflag)) == -1)
924: err(1, "set TCP send buffer size");
925: }
1.83 dtucker 926: }
927:
928: int
1.102 haesbaer 929: map_tos(char *s, int *val)
1.83 dtucker 930: {
1.102 haesbaer 931: /* DiffServ Codepoints and other TOS mappings */
932: const struct toskeywords {
933: const char *keyword;
934: int val;
935: } *t, toskeywords[] = {
936: { "af11", IPTOS_DSCP_AF11 },
937: { "af12", IPTOS_DSCP_AF12 },
938: { "af13", IPTOS_DSCP_AF13 },
939: { "af21", IPTOS_DSCP_AF21 },
940: { "af22", IPTOS_DSCP_AF22 },
941: { "af23", IPTOS_DSCP_AF23 },
942: { "af31", IPTOS_DSCP_AF31 },
943: { "af32", IPTOS_DSCP_AF32 },
944: { "af33", IPTOS_DSCP_AF33 },
945: { "af41", IPTOS_DSCP_AF41 },
946: { "af42", IPTOS_DSCP_AF42 },
947: { "af43", IPTOS_DSCP_AF43 },
948: { "critical", IPTOS_PREC_CRITIC_ECP },
949: { "cs0", IPTOS_DSCP_CS0 },
950: { "cs1", IPTOS_DSCP_CS1 },
951: { "cs2", IPTOS_DSCP_CS2 },
952: { "cs3", IPTOS_DSCP_CS3 },
953: { "cs4", IPTOS_DSCP_CS4 },
954: { "cs5", IPTOS_DSCP_CS5 },
955: { "cs6", IPTOS_DSCP_CS6 },
956: { "cs7", IPTOS_DSCP_CS7 },
957: { "ef", IPTOS_DSCP_EF },
958: { "inetcontrol", IPTOS_PREC_INTERNETCONTROL },
959: { "lowdelay", IPTOS_LOWDELAY },
960: { "netcontrol", IPTOS_PREC_NETCONTROL },
961: { "reliability", IPTOS_RELIABILITY },
962: { "throughput", IPTOS_THROUGHPUT },
963: { NULL, -1 },
964: };
965:
966: for (t = toskeywords; t->keyword != NULL; t++) {
967: if (strcmp(s, t->keyword) == 0) {
968: *val = t->val;
969: return (1);
970: }
971: }
1.83 dtucker 972:
1.102 haesbaer 973: return (0);
1.108 haesbaer 974: }
975:
976: void
977: report_connect(const struct sockaddr *sa, socklen_t salen)
978: {
979: char remote_host[NI_MAXHOST];
980: char remote_port[NI_MAXSERV];
981: int herr;
982: int flags = NI_NUMERICSERV;
983:
984: if (nflag)
985: flags |= NI_NUMERICHOST;
986:
987: if ((herr = getnameinfo(sa, salen,
988: remote_host, sizeof(remote_host),
989: remote_port, sizeof(remote_port),
990: flags)) != 0) {
991: if (herr == EAI_SYSTEM)
992: err(1, "getnameinfo");
993: else
994: errx(1, "getnameinfo: %s", gai_strerror(herr));
995: }
996:
997: fprintf(stderr,
998: "Connection from %s %s "
999: "received!\n", remote_host, remote_port);
1.7 deraadt 1000: }
1.1 deraadt 1001:
1.11 ericj 1002: void
1.58 deraadt 1003: help(void)
1.1 deraadt 1004: {
1.21 ericj 1005: usage(0);
1006: fprintf(stderr, "\tCommand Summary:\n\
1007: \t-4 Use IPv4\n\
1008: \t-6 Use IPv6\n\
1.73 markus 1009: \t-D Enable the debug socket option\n\
1.69 tedu 1010: \t-d Detach from stdin\n\
1.21 ericj 1011: \t-h This help text\n\
1.90 djm 1012: \t-I length TCP receive buffer length\n\
1.21 ericj 1013: \t-i secs\t Delay interval for lines sent, ports scanned\n\
1014: \t-k Keep inbound sockets open for multiple connects\n\
1015: \t-l Listen mode, for inbound connects\n\
1.22 jasoni 1016: \t-n Suppress name/port resolutions\n\
1.90 djm 1017: \t-O length TCP send buffer length\n\
1.86 djm 1018: \t-P proxyuser\tUsername for proxy authentication\n\
1.36 jakob 1019: \t-p port\t Specify local port for remote connects\n\
1.21 ericj 1020: \t-r Randomize remote ports\n\
1.67 jmc 1021: \t-S Enable the TCP MD5 signature option\n\
1.21 ericj 1022: \t-s addr\t Local source address\n\
1.102 haesbaer 1023: \t-T toskeyword\tSet IP Type of Service\n\
1.21 ericj 1024: \t-t Answer TELNET negotiation\n\
1.67 jmc 1025: \t-U Use UNIX domain socket\n\
1.21 ericj 1026: \t-u UDP mode\n\
1.98 guenther 1027: \t-V rtable Specify alternate routing table\n\
1.21 ericj 1028: \t-v Verbose\n\
1029: \t-w secs\t Timeout for connects and final net reads\n\
1.75 djm 1030: \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\
1031: \t-x addr[:port]\tSpecify proxy address and port\n\
1.21 ericj 1032: \t-z Zero-I/O mode [used for scanning]\n\
1033: Port numbers can be individual or ranges: lo-hi [inclusive]\n");
1034: exit(1);
1.11 ericj 1035: }
1036:
1037: void
1.37 jakob 1038: usage(int ret)
1.11 ericj 1039: {
1.92 sobrado 1040: fprintf(stderr,
1041: "usage: nc [-46DdhklnrStUuvz] [-I length] [-i interval] [-O length]\n"
1.100 jeremy 1042: "\t [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n"
1.98 guenther 1043: "\t [-V rtable] [-w timeout] [-X proxy_protocol]\n"
1.100 jeremy 1044: "\t [-x proxy_address[:port]] [destination] [port]\n");
1.21 ericj 1045: if (ret)
1046: exit(1);
1.7 deraadt 1047: }
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