Annotation of src/usr.bin/nc/netcat.c, Revision 1.117
1.117 ! sthen 1: /* $OpenBSD: netcat.c,v 1.116 2013/10/21 09:12:55 phessler 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>
1.113 djm 37: #include <sys/uio.h>
1.42 ericj 38: #include <sys/un.h>
1.21 ericj 39:
1.7 deraadt 40: #include <netinet/in.h>
1.83 dtucker 41: #include <netinet/in_systm.h>
1.65 markus 42: #include <netinet/tcp.h>
1.83 dtucker 43: #include <netinet/ip.h>
1.21 ericj 44: #include <arpa/telnet.h>
1.29 smart 45:
1.11 ericj 46: #include <err.h>
1.7 deraadt 47: #include <errno.h>
1.21 ericj 48: #include <netdb.h>
49: #include <poll.h>
1.13 ericj 50: #include <stdarg.h>
1.21 ericj 51: #include <stdio.h>
1.1 deraadt 52: #include <stdlib.h>
1.21 ericj 53: #include <string.h>
1.5 art 54: #include <unistd.h>
1.42 ericj 55: #include <fcntl.h>
1.85 millert 56: #include <limits.h>
1.79 avsm 57: #include "atomicio.h"
1.51 vincent 58:
59: #ifndef SUN_LEN
60: #define SUN_LEN(su) \
61: (sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))
62: #endif
1.1 deraadt 63:
1.55 fgsch 64: #define PORT_MAX 65535
65: #define PORT_MAX_LEN 6
1.99 jeremy 66: #define UNIX_DG_TMP_SOCKET_SIZE 19
1.31 ericj 67:
1.21 ericj 68: /* Command Line Options */
1.68 tedu 69: int dflag; /* detached, no stdin */
1.113 djm 70: int Fflag; /* fdpass sock to stdout */
1.88 ray 71: unsigned int iflag; /* Interval Flag */
1.21 ericj 72: int kflag; /* More than one connect */
73: int lflag; /* Bind to local port */
1.111 sthen 74: int Nflag; /* shutdown() network socket */
1.67 jmc 75: int nflag; /* Don't do name look up */
1.86 djm 76: char *Pflag; /* Proxy username */
1.21 ericj 77: char *pflag; /* Localport flag */
78: int rflag; /* Random ports flag */
79: char *sflag; /* Source Address */
80: int tflag; /* Telnet Emulation */
81: int uflag; /* UDP - Default to TCP */
82: int vflag; /* Verbosity */
1.34 jakob 83: int xflag; /* Socks proxy */
1.21 ericj 84: int zflag; /* Port Scan Flag */
1.73 markus 85: int Dflag; /* sodebug */
1.90 djm 86: int Iflag; /* TCP receive buffer size */
87: int Oflag; /* TCP send buffer size */
1.65 markus 88: int Sflag; /* TCP MD5 signature option */
1.83 dtucker 89: int Tflag = -1; /* IP Type of Service */
1.117 ! sthen 90: int rtableid = -1;
1.21 ericj 91:
1.49 hugh 92: int timeout = -1;
1.21 ericj 93: int family = AF_UNSPEC;
1.63 miod 94: char *portlist[PORT_MAX+1];
1.99 jeremy 95: char *unix_dg_tmp_socket;
1.21 ericj 96:
1.40 millert 97: void atelnet(int, unsigned char *, unsigned int);
98: void build_ports(char *);
99: void help(void);
100: int local_listen(char *, char *, struct addrinfo);
101: void readwrite(int);
1.113 djm 102: void fdpass(int nfd) __attribute__((noreturn));
1.77 otto 103: int remote_connect(const char *, const char *, struct addrinfo);
1.103 fgsch 104: int timeout_connect(int, const struct sockaddr *, socklen_t);
1.86 djm 105: int socks_connect(const char *, const char *, struct addrinfo,
106: const char *, const char *, struct addrinfo, int, const char *);
1.40 millert 107: int udptest(int);
1.99 jeremy 108: int unix_bind(char *);
1.42 ericj 109: int unix_connect(char *);
110: int unix_listen(char *);
1.84 dtucker 111: void set_common_sockopts(int);
1.102 haesbaer 112: int map_tos(char *, int *);
1.108 haesbaer 113: void report_connect(const struct sockaddr *, socklen_t);
1.40 millert 114: void usage(int);
1.1 deraadt 115:
1.21 ericj 116: int
1.37 jakob 117: main(int argc, char *argv[])
1.21 ericj 118: {
1.46 markus 119: int ch, s, ret, socksv;
1.88 ray 120: char *host, *uport;
1.21 ericj 121: struct addrinfo hints;
1.29 smart 122: struct servent *sv;
1.21 ericj 123: socklen_t len;
1.76 hshoexer 124: struct sockaddr_storage cliaddr;
1.34 jakob 125: char *proxy;
1.88 ray 126: const char *errstr, *proxyhost = "", *proxyport = NULL;
1.34 jakob 127: struct addrinfo proxyhints;
1.99 jeremy 128: char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE];
1.11 ericj 129:
1.29 smart 130: ret = 1;
131: s = 0;
1.46 markus 132: socksv = 5;
1.29 smart 133: host = NULL;
134: uport = NULL;
135: sv = NULL;
1.116 phessler 136: rtableid = getrtable();
1.29 smart 137:
1.80 mcbride 138: while ((ch = getopt(argc, argv,
1.113 djm 139: "46DdFhI:i:klNnO:P:p:rSs:tT:UuV:vw:X:x:z")) != -1) {
1.21 ericj 140: switch (ch) {
141: case '4':
142: family = AF_INET;
143: break;
144: case '6':
145: family = AF_INET6;
146: break;
1.42 ericj 147: case 'U':
148: family = AF_UNIX;
149: break;
1.46 markus 150: case 'X':
1.75 djm 151: if (strcasecmp(optarg, "connect") == 0)
152: socksv = -1; /* HTTP proxy CONNECT */
153: else if (strcmp(optarg, "4") == 0)
154: socksv = 4; /* SOCKS v.4 */
155: else if (strcmp(optarg, "5") == 0)
156: socksv = 5; /* SOCKS v.5 */
157: else
158: errx(1, "unsupported proxy protocol");
1.46 markus 159: break;
1.68 tedu 160: case 'd':
161: dflag = 1;
162: break;
1.113 djm 163: case 'F':
164: Fflag = 1;
165: break;
1.21 ericj 166: case 'h':
167: help();
168: break;
169: case 'i':
1.88 ray 170: iflag = strtonum(optarg, 0, UINT_MAX, &errstr);
171: if (errstr)
172: errx(1, "interval %s: %s", errstr, optarg);
1.21 ericj 173: break;
174: case 'k':
175: kflag = 1;
176: break;
177: case 'l':
178: lflag = 1;
179: break;
1.111 sthen 180: case 'N':
181: Nflag = 1;
182: break;
1.21 ericj 183: case 'n':
184: nflag = 1;
185: break;
1.86 djm 186: case 'P':
187: Pflag = optarg;
188: break;
1.21 ericj 189: case 'p':
190: pflag = optarg;
191: break;
192: case 'r':
193: rflag = 1;
194: break;
195: case 's':
196: sflag = optarg;
197: break;
198: case 't':
199: tflag = 1;
200: break;
201: case 'u':
202: uflag = 1;
203: break;
1.93 claudio 204: case 'V':
1.117 ! sthen 205: rtableid = (int)strtonum(optarg, 0,
1.93 claudio 206: RT_TABLEID_MAX, &errstr);
207: if (errstr)
1.98 guenther 208: errx(1, "rtable %s: %s", errstr, optarg);
1.93 claudio 209: break;
1.21 ericj 210: case 'v':
211: vflag = 1;
212: break;
1.70 deraadt 213: case 'w':
1.88 ray 214: timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr);
215: if (errstr)
216: errx(1, "timeout %s: %s", errstr, optarg);
1.49 hugh 217: timeout *= 1000;
1.21 ericj 218: break;
1.34 jakob 219: case 'x':
220: xflag = 1;
1.64 deraadt 221: if ((proxy = strdup(optarg)) == NULL)
222: err(1, NULL);
1.34 jakob 223: break;
1.21 ericj 224: case 'z':
225: zflag = 1;
226: break;
1.73 markus 227: case 'D':
228: Dflag = 1;
229: break;
1.90 djm 230: case 'I':
231: Iflag = strtonum(optarg, 1, 65536 << 14, &errstr);
232: if (errstr != NULL)
233: errx(1, "TCP receive window %s: %s",
234: errstr, optarg);
235: break;
236: case 'O':
237: Oflag = strtonum(optarg, 1, 65536 << 14, &errstr);
238: if (errstr != NULL)
239: errx(1, "TCP send window %s: %s",
240: errstr, optarg);
241: break;
1.65 markus 242: case 'S':
243: Sflag = 1;
244: break;
1.83 dtucker 245: case 'T':
1.102 haesbaer 246: errstr = NULL;
247: errno = 0;
248: if (map_tos(optarg, &Tflag))
249: break;
250: if (strlen(optarg) > 1 && optarg[0] == '0' &&
251: optarg[1] == 'x')
252: Tflag = (int)strtol(optarg, NULL, 16);
253: else
254: Tflag = (int)strtonum(optarg, 0, 255,
255: &errstr);
256: if (Tflag < 0 || Tflag > 255 || errstr || errno)
257: errx(1, "illegal tos value %s", optarg);
1.83 dtucker 258: break;
1.21 ericj 259: default:
260: usage(1);
261: }
262: }
263: argc -= optind;
264: argv += optind;
1.11 ericj 265:
1.21 ericj 266: /* Cruft to make sure options are clean, and used properly. */
1.42 ericj 267: if (argv[0] && !argv[1] && family == AF_UNIX) {
268: host = argv[0];
269: uport = NULL;
270: } else if (argv[0] && !argv[1]) {
1.21 ericj 271: if (!lflag)
272: usage(1);
273: uport = argv[0];
274: host = NULL;
275: } else if (argv[0] && argv[1]) {
276: host = argv[0];
277: uport = argv[1];
278: } else
279: usage(1);
1.1 deraadt 280:
1.21 ericj 281: if (lflag && sflag)
282: errx(1, "cannot use -s and -l");
283: if (lflag && pflag)
284: errx(1, "cannot use -p and -l");
285: if (lflag && zflag)
1.32 ericj 286: errx(1, "cannot use -z and -l");
1.21 ericj 287: if (!lflag && kflag)
1.32 ericj 288: errx(1, "must use -l with -k");
1.21 ericj 289:
1.99 jeremy 290: /* Get name of temporary socket for unix datagram client */
291: if ((family == AF_UNIX) && uflag && !lflag) {
292: if (sflag) {
293: unix_dg_tmp_socket = sflag;
294: } else {
295: strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX",
296: UNIX_DG_TMP_SOCKET_SIZE);
297: if (mktemp(unix_dg_tmp_socket_buf) == NULL)
298: err(1, "mktemp");
299: unix_dg_tmp_socket = unix_dg_tmp_socket_buf;
300: }
301: }
302:
1.67 jmc 303: /* Initialize addrinfo structure. */
1.42 ericj 304: if (family != AF_UNIX) {
305: memset(&hints, 0, sizeof(struct addrinfo));
306: hints.ai_family = family;
307: hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
308: hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
309: if (nflag)
310: hints.ai_flags |= AI_NUMERICHOST;
311: }
1.1 deraadt 312:
1.34 jakob 313: if (xflag) {
314: if (uflag)
315: errx(1, "no proxy support for UDP mode");
316:
317: if (lflag)
318: errx(1, "no proxy support for listen");
319:
1.42 ericj 320: if (family == AF_UNIX)
321: errx(1, "no proxy support for unix sockets");
322:
1.34 jakob 323: /* XXX IPv6 transport to proxy would probably work */
324: if (family == AF_INET6)
325: errx(1, "no proxy support for IPv6");
326:
327: if (sflag)
328: errx(1, "no proxy support for local source address");
329:
330: proxyhost = strsep(&proxy, ":");
331: proxyport = proxy;
332:
333: memset(&proxyhints, 0, sizeof(struct addrinfo));
334: proxyhints.ai_family = family;
335: proxyhints.ai_socktype = SOCK_STREAM;
336: proxyhints.ai_protocol = IPPROTO_TCP;
337: if (nflag)
338: proxyhints.ai_flags |= AI_NUMERICHOST;
339: }
340:
1.21 ericj 341: if (lflag) {
342: int connfd;
1.27 ericj 343: ret = 0;
1.1 deraadt 344:
1.99 jeremy 345: if (family == AF_UNIX) {
346: if (uflag)
347: s = unix_bind(host);
348: else
349: s = unix_listen(host);
350: }
1.42 ericj 351:
1.67 jmc 352: /* Allow only one connection at a time, but stay alive. */
1.21 ericj 353: for (;;) {
1.42 ericj 354: if (family != AF_UNIX)
355: s = local_listen(host, uport, hints);
356: if (s < 0)
1.30 smart 357: err(1, NULL);
1.21 ericj 358: /*
1.109 haesbaer 359: * For UDP and -k, don't connect the socket, let it
360: * receive datagrams from multiple socket pairs.
1.21 ericj 361: */
1.109 haesbaer 362: if (uflag && kflag)
363: readwrite(s);
364: /*
365: * For UDP and not -k, we will use recvfrom() initially
366: * to wait for a caller, then use the regular functions
367: * to talk to the caller.
368: */
369: else if (uflag && !kflag) {
1.80 mcbride 370: int rv, plen;
1.97 nicm 371: char buf[16384];
1.21 ericj 372: struct sockaddr_storage z;
373:
374: len = sizeof(z);
1.106 dlg 375: plen = 2048;
1.80 mcbride 376: rv = recvfrom(s, buf, plen, MSG_PEEK,
1.37 jakob 377: (struct sockaddr *)&z, &len);
1.23 ericj 378: if (rv < 0)
1.57 stevesk 379: err(1, "recvfrom");
1.21 ericj 380:
1.37 jakob 381: rv = connect(s, (struct sockaddr *)&z, len);
1.23 ericj 382: if (rv < 0)
1.57 stevesk 383: err(1, "connect");
1.1 deraadt 384:
1.108 haesbaer 385: if (vflag)
386: report_connect((struct sockaddr *)&z, len);
387:
1.99 jeremy 388: readwrite(s);
1.21 ericj 389: } else {
1.78 otto 390: len = sizeof(cliaddr);
1.21 ericj 391: connfd = accept(s, (struct sockaddr *)&cliaddr,
1.37 jakob 392: &len);
1.110 deraadt 393: if (connfd == -1) {
394: /* For now, all errnos are fatal */
395: err(1, "accept");
396: }
1.108 haesbaer 397: if (vflag)
398: report_connect((struct sockaddr *)&cliaddr, len);
399:
1.99 jeremy 400: readwrite(connfd);
401: close(connfd);
1.21 ericj 402: }
1.1 deraadt 403:
1.42 ericj 404: if (family != AF_UNIX)
405: close(s);
1.99 jeremy 406: else if (uflag) {
407: if (connect(s, NULL, 0) < 0)
408: err(1, "connect");
409: }
1.27 ericj 410:
1.21 ericj 411: if (!kflag)
412: break;
1.11 ericj 413: }
1.42 ericj 414: } else if (family == AF_UNIX) {
415: ret = 0;
416:
417: if ((s = unix_connect(host)) > 0 && !zflag) {
418: readwrite(s);
419: close(s);
420: } else
421: ret = 1;
422:
1.99 jeremy 423: if (uflag)
424: unlink(unix_dg_tmp_socket);
1.42 ericj 425: exit(ret);
426:
1.21 ericj 427: } else {
428: int i = 0;
1.6 deraadt 429:
1.67 jmc 430: /* Construct the portlist[] array. */
1.21 ericj 431: build_ports(uport);
1.1 deraadt 432:
1.67 jmc 433: /* Cycle through portlist, connecting to each port. */
1.21 ericj 434: for (i = 0; portlist[i] != NULL; i++) {
435: if (s)
436: close(s);
1.34 jakob 437:
438: if (xflag)
439: s = socks_connect(host, portlist[i], hints,
1.86 djm 440: proxyhost, proxyport, proxyhints, socksv,
441: Pflag);
1.34 jakob 442: else
443: s = remote_connect(host, portlist[i], hints);
444:
445: if (s < 0)
1.21 ericj 446: continue;
1.1 deraadt 447:
1.21 ericj 448: ret = 0;
449: if (vflag || zflag) {
1.67 jmc 450: /* For UDP, make sure we are connected. */
1.21 ericj 451: if (uflag) {
1.50 vincent 452: if (udptest(s) == -1) {
1.21 ericj 453: ret = 1;
454: continue;
455: }
456: }
1.1 deraadt 457:
1.67 jmc 458: /* Don't look up port if -n. */
1.21 ericj 459: if (nflag)
460: sv = NULL;
461: else {
462: sv = getservbyport(
1.37 jakob 463: ntohs(atoi(portlist[i])),
464: uflag ? "udp" : "tcp");
1.21 ericj 465: }
1.50 vincent 466:
1.94 mpf 467: fprintf(stderr,
468: "Connection to %s %s port [%s/%s] "
469: "succeeded!\n", host, portlist[i],
470: uflag ? "udp" : "tcp",
1.37 jakob 471: sv ? sv->s_name : "*");
1.21 ericj 472: }
1.113 djm 473: if (Fflag)
474: fdpass(s);
475: else if (!zflag)
1.21 ericj 476: readwrite(s);
1.7 deraadt 477: }
1.11 ericj 478: }
1.1 deraadt 479:
1.21 ericj 480: if (s)
481: close(s);
482:
483: exit(ret);
1.7 deraadt 484: }
1.1 deraadt 485:
1.11 ericj 486: /*
1.99 jeremy 487: * unix_bind()
488: * Returns a unix socket bound to the given path
1.42 ericj 489: */
490: int
1.99 jeremy 491: unix_bind(char *path)
1.42 ericj 492: {
493: struct sockaddr_un sun;
494: int s;
495:
1.99 jeremy 496: /* Create unix domain socket. */
497: if ((s = socket(AF_UNIX, uflag ? SOCK_DGRAM : SOCK_STREAM,
498: 0)) < 0)
1.50 vincent 499: return (-1);
1.42 ericj 500:
501: memset(&sun, 0, sizeof(struct sockaddr_un));
502: sun.sun_family = AF_UNIX;
1.60 avsm 503:
504: if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
505: sizeof(sun.sun_path)) {
506: close(s);
507: errno = ENAMETOOLONG;
508: return (-1);
509: }
1.99 jeremy 510:
511: if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
1.50 vincent 512: close(s);
513: return (-1);
1.42 ericj 514: }
515: return (s);
516: }
517:
518: /*
1.99 jeremy 519: * unix_connect()
520: * Returns a socket connected to a local unix socket. Returns -1 on failure.
1.42 ericj 521: */
522: int
1.99 jeremy 523: unix_connect(char *path)
1.42 ericj 524: {
525: struct sockaddr_un sun;
526: int s;
527:
1.99 jeremy 528: if (uflag) {
529: if ((s = unix_bind(unix_dg_tmp_socket)) < 0)
530: return (-1);
531: } else {
532: if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
533: return (-1);
534: }
1.112 okan 535: (void)fcntl(s, F_SETFD, FD_CLOEXEC);
1.42 ericj 536:
1.60 avsm 537: memset(&sun, 0, sizeof(struct sockaddr_un));
1.42 ericj 538: sun.sun_family = AF_UNIX;
1.60 avsm 539:
540: if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
541: sizeof(sun.sun_path)) {
542: close(s);
543: errno = ENAMETOOLONG;
544: return (-1);
545: }
1.99 jeremy 546: if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
1.42 ericj 547: close(s);
548: return (-1);
549: }
1.99 jeremy 550: return (s);
551:
552: }
553:
554: /*
555: * unix_listen()
556: * Create a unix domain socket, and listen on it.
557: */
558: int
559: unix_listen(char *path)
560: {
561: int s;
562: if ((s = unix_bind(path)) < 0)
563: return (-1);
1.42 ericj 564:
565: if (listen(s, 5) < 0) {
566: close(s);
567: return (-1);
568: }
569: return (s);
570: }
571:
572: /*
1.21 ericj 573: * remote_connect()
1.67 jmc 574: * Returns a socket connected to a remote host. Properly binds to a local
575: * port or source address if needed. Returns -1 on failure.
1.11 ericj 576: */
1.21 ericj 577: int
1.77 otto 578: remote_connect(const char *host, const char *port, struct addrinfo hints)
1.21 ericj 579: {
580: struct addrinfo *res, *res0;
1.91 markus 581: int s, error, on = 1;
1.21 ericj 582:
583: if ((error = getaddrinfo(host, port, &hints, &res)))
1.56 stevesk 584: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.21 ericj 585:
586: res0 = res;
587: do {
588: if ((s = socket(res0->ai_family, res0->ai_socktype,
1.37 jakob 589: res0->ai_protocol)) < 0)
1.21 ericj 590: continue;
591:
1.117 ! sthen 592: if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_RTABLE,
! 593: &rtableid, sizeof(rtableid)) == -1))
1.115 phessler 594: err(1, "setsockopt SO_RTABLE");
1.93 claudio 595:
1.67 jmc 596: /* Bind to a local port or source address if specified. */
1.21 ericj 597: if (sflag || pflag) {
598: struct addrinfo ahints, *ares;
1.6 deraadt 599:
1.91 markus 600: /* try SO_BINDANY, but don't insist */
601: setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on));
1.21 ericj 602: memset(&ahints, 0, sizeof(struct addrinfo));
603: ahints.ai_family = res0->ai_family;
604: ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
605: ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
1.25 ericj 606: ahints.ai_flags = AI_PASSIVE;
1.38 jakob 607: if ((error = getaddrinfo(sflag, pflag, &ahints, &ares)))
1.56 stevesk 608: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.21 ericj 609:
610: if (bind(s, (struct sockaddr *)ares->ai_addr,
1.62 millert 611: ares->ai_addrlen) < 0)
1.21 ericj 612: errx(1, "bind failed: %s", strerror(errno));
613: freeaddrinfo(ares);
1.6 deraadt 614: }
1.81 marius 615:
616: set_common_sockopts(s);
1.6 deraadt 617:
1.103 fgsch 618: if (timeout_connect(s, res0->ai_addr, res0->ai_addrlen) == 0)
1.6 deraadt 619: break;
1.71 mcbride 620: else if (vflag)
621: warn("connect to %s port %s (%s) failed", host, port,
622: uflag ? "udp" : "tcp");
1.34 jakob 623:
1.21 ericj 624: close(s);
625: s = -1;
626: } while ((res0 = res0->ai_next) != NULL);
627:
628: freeaddrinfo(res);
1.1 deraadt 629:
1.21 ericj 630: return (s);
1.103 fgsch 631: }
632:
633: int
634: timeout_connect(int s, const struct sockaddr *name, socklen_t namelen)
635: {
636: struct pollfd pfd;
637: socklen_t optlen;
638: int flags, optval;
639: int ret;
640:
641: if (timeout != -1) {
642: flags = fcntl(s, F_GETFL, 0);
643: if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1)
644: err(1, "set non-blocking mode");
645: }
646:
647: if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) {
648: pfd.fd = s;
649: pfd.events = POLLOUT;
650: if ((ret = poll(&pfd, 1, timeout)) == 1) {
651: optlen = sizeof(optval);
652: if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR,
653: &optval, &optlen)) == 0) {
654: errno = optval;
655: ret = optval == 0 ? 0 : -1;
656: }
657: } else if (ret == 0) {
658: errno = ETIMEDOUT;
659: ret = -1;
660: } else
661: err(1, "poll failed");
662: }
663:
664: if (timeout != -1 && fcntl(s, F_SETFL, flags) == -1)
665: err(1, "restoring flags");
666:
667: return (ret);
1.7 deraadt 668: }
1.1 deraadt 669:
1.11 ericj 670: /*
1.21 ericj 671: * local_listen()
1.67 jmc 672: * Returns a socket listening on a local port, binds to specified source
673: * address. Returns -1 on failure.
1.11 ericj 674: */
1.21 ericj 675: int
1.37 jakob 676: local_listen(char *host, char *port, struct addrinfo hints)
1.21 ericj 677: {
678: struct addrinfo *res, *res0;
679: int s, ret, x = 1;
680: int error;
1.6 deraadt 681:
1.67 jmc 682: /* Allow nodename to be null. */
1.21 ericj 683: hints.ai_flags |= AI_PASSIVE;
1.7 deraadt 684:
1.21 ericj 685: /*
686: * In the case of binding to a wildcard address
687: * default to binding to an ipv4 address.
688: */
689: if (host == NULL && hints.ai_family == AF_UNSPEC)
690: hints.ai_family = AF_INET;
1.1 deraadt 691:
1.21 ericj 692: if ((error = getaddrinfo(host, port, &hints, &res)))
1.70 deraadt 693: errx(1, "getaddrinfo: %s", gai_strerror(error));
1.14 ericj 694:
1.21 ericj 695: res0 = res;
696: do {
697: if ((s = socket(res0->ai_family, res0->ai_socktype,
1.82 marius 698: res0->ai_protocol)) < 0)
1.21 ericj 699: continue;
1.1 deraadt 700:
1.117 ! sthen 701: if (rtableid >= 0 && (setsockopt(s, IPPROTO_IP, SO_RTABLE,
! 702: &rtableid, sizeof(rtableid)) == -1))
1.115 phessler 703: err(1, "setsockopt SO_RTABLE");
1.93 claudio 704:
1.21 ericj 705: ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x));
706: if (ret == -1)
1.30 smart 707: err(1, NULL);
1.81 marius 708:
709: set_common_sockopts(s);
1.1 deraadt 710:
1.21 ericj 711: if (bind(s, (struct sockaddr *)res0->ai_addr,
1.37 jakob 712: res0->ai_addrlen) == 0)
1.21 ericj 713: break;
1.1 deraadt 714:
1.21 ericj 715: close(s);
716: s = -1;
717: } while ((res0 = res0->ai_next) != NULL);
1.1 deraadt 718:
1.47 ericj 719: if (!uflag && s != -1) {
1.21 ericj 720: if (listen(s, 1) < 0)
1.57 stevesk 721: err(1, "listen");
1.12 ericj 722: }
1.1 deraadt 723:
1.21 ericj 724: freeaddrinfo(res);
1.1 deraadt 725:
1.21 ericj 726: return (s);
1.7 deraadt 727: }
728:
1.11 ericj 729: /*
1.21 ericj 730: * readwrite()
731: * Loop that polls on the network file descriptor and stdin.
1.11 ericj 732: */
1.21 ericj 733: void
1.37 jakob 734: readwrite(int nfd)
1.6 deraadt 735: {
1.52 vincent 736: struct pollfd pfd[2];
1.97 nicm 737: unsigned char buf[16384];
1.79 avsm 738: int n, wfd = fileno(stdin);
1.21 ericj 739: int lfd = fileno(stdout);
1.80 mcbride 740: int plen;
741:
1.106 dlg 742: plen = 2048;
1.21 ericj 743:
744: /* Setup Network FD */
745: pfd[0].fd = nfd;
746: pfd[0].events = POLLIN;
747:
1.67 jmc 748: /* Set up STDIN FD. */
1.21 ericj 749: pfd[1].fd = wfd;
750: pfd[1].events = POLLIN;
751:
1.54 aaron 752: while (pfd[0].fd != -1) {
1.21 ericj 753: if (iflag)
754: sleep(iflag);
755:
1.68 tedu 756: if ((n = poll(pfd, 2 - dflag, timeout)) < 0) {
1.21 ericj 757: close(nfd);
1.52 vincent 758: err(1, "Polling Error");
1.21 ericj 759: }
1.49 hugh 760:
761: if (n == 0)
762: return;
1.21 ericj 763:
764: if (pfd[0].revents & POLLIN) {
1.80 mcbride 765: if ((n = read(nfd, buf, plen)) < 0)
1.21 ericj 766: return;
1.52 vincent 767: else if (n == 0) {
768: shutdown(nfd, SHUT_RD);
769: pfd[0].fd = -1;
770: pfd[0].events = 0;
1.21 ericj 771: } else {
772: if (tflag)
773: atelnet(nfd, buf, n);
1.79 avsm 774: if (atomicio(vwrite, lfd, buf, n) != n)
1.21 ericj 775: return;
1.6 deraadt 776: }
1.21 ericj 777: }
778:
1.68 tedu 779: if (!dflag && pfd[1].revents & POLLIN) {
1.80 mcbride 780: if ((n = read(wfd, buf, plen)) < 0)
1.21 ericj 781: return;
1.52 vincent 782: else if (n == 0) {
1.111 sthen 783: if (Nflag)
784: shutdown(nfd, SHUT_WR);
1.52 vincent 785: pfd[1].fd = -1;
786: pfd[1].events = 0;
787: } else {
1.79 avsm 788: if (atomicio(vwrite, nfd, buf, n) != n)
1.21 ericj 789: return;
1.50 vincent 790: }
1.21 ericj 791: }
1.11 ericj 792: }
1.113 djm 793: }
794:
795: /*
796: * fdpass()
797: * Pass the connected file descriptor to stdout and exit.
798: */
799: void
800: fdpass(int nfd)
801: {
802: struct msghdr mh;
803: union {
804: struct cmsghdr hdr;
805: char buf[CMSG_SPACE(sizeof(int))];
806: } cmsgbuf;
807: struct cmsghdr *cmsg;
808: struct iovec iov;
809: char c = '\0';
810: ssize_t r;
811: struct pollfd pfd;
812:
813: /* Avoid obvious stupidity */
814: if (isatty(STDOUT_FILENO))
815: errx(1, "Cannot pass file descriptor to tty");
816:
817: bzero(&mh, sizeof(mh));
818: bzero(&cmsgbuf, sizeof(cmsgbuf));
819: bzero(&iov, sizeof(iov));
820: bzero(&pfd, sizeof(pfd));
821:
822: mh.msg_control = (caddr_t)&cmsgbuf.buf;
823: mh.msg_controllen = sizeof(cmsgbuf.buf);
824: cmsg = CMSG_FIRSTHDR(&mh);
825: cmsg->cmsg_len = CMSG_LEN(sizeof(int));
826: cmsg->cmsg_level = SOL_SOCKET;
827: cmsg->cmsg_type = SCM_RIGHTS;
828: *(int *)CMSG_DATA(cmsg) = nfd;
829:
830: iov.iov_base = &c;
831: iov.iov_len = 1;
832: mh.msg_iov = &iov;
833: mh.msg_iovlen = 1;
834:
835: bzero(&pfd, sizeof(pfd));
836: pfd.fd = STDOUT_FILENO;
837: for (;;) {
838: r = sendmsg(STDOUT_FILENO, &mh, 0);
839: if (r == -1) {
840: if (errno == EAGAIN || errno == EINTR) {
841: pfd.events = POLLOUT;
842: if (poll(&pfd, 1, -1) == -1)
843: err(1, "poll");
844: continue;
845: }
846: err(1, "sendmsg");
847: } else if (r == -1)
848: errx(1, "sendmsg: unexpected return value %zd", r);
849: else
850: break;
851: }
852: exit(0);
1.7 deraadt 853: }
1.50 vincent 854:
1.67 jmc 855: /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */
1.21 ericj 856: void
1.37 jakob 857: atelnet(int nfd, unsigned char *buf, unsigned int size)
1.6 deraadt 858: {
1.24 ericj 859: unsigned char *p, *end;
860: unsigned char obuf[4];
861:
1.95 nicm 862: if (size < 3)
863: return;
864: end = buf + size - 2;
1.24 ericj 865:
866: for (p = buf; p < end; p++) {
1.21 ericj 867: if (*p != IAC)
1.95 nicm 868: continue;
1.24 ericj 869:
1.25 ericj 870: obuf[0] = IAC;
1.24 ericj 871: p++;
1.50 vincent 872: if ((*p == WILL) || (*p == WONT))
1.24 ericj 873: obuf[1] = DONT;
1.95 nicm 874: else if ((*p == DO) || (*p == DONT))
1.24 ericj 875: obuf[1] = WONT;
1.95 nicm 876: else
877: continue;
878:
879: p++;
880: obuf[2] = *p;
881: if (atomicio(vwrite, nfd, obuf, 3) != 3)
882: warn("Write Error!");
1.11 ericj 883: }
1.7 deraadt 884: }
885:
1.11 ericj 886: /*
1.21 ericj 887: * build_ports()
1.105 lum 888: * Build an array of ports in portlist[], listing each port
1.67 jmc 889: * that we should try to connect to.
1.11 ericj 890: */
1.21 ericj 891: void
1.37 jakob 892: build_ports(char *p)
1.6 deraadt 893: {
1.88 ray 894: const char *errstr;
895: char *n;
1.21 ericj 896: int hi, lo, cp;
897: int x = 0;
898:
899: if ((n = strchr(p, '-')) != NULL) {
900: *n = '\0';
901: n++;
902:
1.67 jmc 903: /* Make sure the ports are in order: lowest->highest. */
1.88 ray 904: hi = strtonum(n, 1, PORT_MAX, &errstr);
905: if (errstr)
906: errx(1, "port number %s: %s", errstr, n);
907: lo = strtonum(p, 1, PORT_MAX, &errstr);
908: if (errstr)
909: errx(1, "port number %s: %s", errstr, p);
1.21 ericj 910:
911: if (lo > hi) {
912: cp = hi;
913: hi = lo;
914: lo = cp;
915: }
916:
1.67 jmc 917: /* Load ports sequentially. */
1.21 ericj 918: for (cp = lo; cp <= hi; cp++) {
1.55 fgsch 919: portlist[x] = calloc(1, PORT_MAX_LEN);
920: if (portlist[x] == NULL)
921: err(1, NULL);
922: snprintf(portlist[x], PORT_MAX_LEN, "%d", cp);
1.21 ericj 923: x++;
924: }
925:
1.67 jmc 926: /* Randomly swap ports. */
1.21 ericj 927: if (rflag) {
928: int y;
929: char *c;
930:
931: for (x = 0; x <= (hi - lo); x++) {
932: y = (arc4random() & 0xFFFF) % (hi - lo);
933: c = portlist[x];
934: portlist[x] = portlist[y];
935: portlist[y] = c;
1.6 deraadt 936: }
1.11 ericj 937: }
1.21 ericj 938: } else {
1.88 ray 939: hi = strtonum(p, 1, PORT_MAX, &errstr);
940: if (errstr)
941: errx(1, "port number %s: %s", errstr, p);
1.96 nicm 942: portlist[0] = strdup(p);
1.55 fgsch 943: if (portlist[0] == NULL)
944: err(1, NULL);
1.11 ericj 945: }
1.13 ericj 946: }
947:
948: /*
1.21 ericj 949: * udptest()
950: * Do a few writes to see if the UDP port is there.
1.105 lum 951: * Fails once PF state table is full.
1.13 ericj 952: */
1.21 ericj 953: int
1.37 jakob 954: udptest(int s)
1.13 ericj 955: {
1.74 deraadt 956: int i, ret;
1.13 ericj 957:
1.52 vincent 958: for (i = 0; i <= 3; i++) {
1.74 deraadt 959: if (write(s, "X", 1) == 1)
1.21 ericj 960: ret = 1;
1.14 ericj 961: else
1.21 ericj 962: ret = -1;
1.14 ericj 963: }
1.21 ericj 964: return (ret);
1.81 marius 965: }
966:
1.84 dtucker 967: void
1.81 marius 968: set_common_sockopts(int s)
969: {
970: int x = 1;
971:
972: if (Sflag) {
973: if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
974: &x, sizeof(x)) == -1)
975: err(1, NULL);
976: }
977: if (Dflag) {
978: if (setsockopt(s, SOL_SOCKET, SO_DEBUG,
979: &x, sizeof(x)) == -1)
980: err(1, NULL);
981: }
1.83 dtucker 982: if (Tflag != -1) {
983: if (setsockopt(s, IPPROTO_IP, IP_TOS,
984: &Tflag, sizeof(Tflag)) == -1)
985: err(1, "set IP ToS");
986: }
1.90 djm 987: if (Iflag) {
988: if (setsockopt(s, SOL_SOCKET, SO_RCVBUF,
989: &Iflag, sizeof(Iflag)) == -1)
990: err(1, "set TCP receive buffer size");
991: }
992: if (Oflag) {
993: if (setsockopt(s, SOL_SOCKET, SO_SNDBUF,
994: &Oflag, sizeof(Oflag)) == -1)
995: err(1, "set TCP send buffer size");
996: }
1.83 dtucker 997: }
998:
999: int
1.102 haesbaer 1000: map_tos(char *s, int *val)
1.83 dtucker 1001: {
1.102 haesbaer 1002: /* DiffServ Codepoints and other TOS mappings */
1003: const struct toskeywords {
1004: const char *keyword;
1005: int val;
1006: } *t, toskeywords[] = {
1007: { "af11", IPTOS_DSCP_AF11 },
1008: { "af12", IPTOS_DSCP_AF12 },
1009: { "af13", IPTOS_DSCP_AF13 },
1010: { "af21", IPTOS_DSCP_AF21 },
1011: { "af22", IPTOS_DSCP_AF22 },
1012: { "af23", IPTOS_DSCP_AF23 },
1013: { "af31", IPTOS_DSCP_AF31 },
1014: { "af32", IPTOS_DSCP_AF32 },
1015: { "af33", IPTOS_DSCP_AF33 },
1016: { "af41", IPTOS_DSCP_AF41 },
1017: { "af42", IPTOS_DSCP_AF42 },
1018: { "af43", IPTOS_DSCP_AF43 },
1019: { "critical", IPTOS_PREC_CRITIC_ECP },
1020: { "cs0", IPTOS_DSCP_CS0 },
1021: { "cs1", IPTOS_DSCP_CS1 },
1022: { "cs2", IPTOS_DSCP_CS2 },
1023: { "cs3", IPTOS_DSCP_CS3 },
1024: { "cs4", IPTOS_DSCP_CS4 },
1025: { "cs5", IPTOS_DSCP_CS5 },
1026: { "cs6", IPTOS_DSCP_CS6 },
1027: { "cs7", IPTOS_DSCP_CS7 },
1028: { "ef", IPTOS_DSCP_EF },
1029: { "inetcontrol", IPTOS_PREC_INTERNETCONTROL },
1030: { "lowdelay", IPTOS_LOWDELAY },
1031: { "netcontrol", IPTOS_PREC_NETCONTROL },
1032: { "reliability", IPTOS_RELIABILITY },
1033: { "throughput", IPTOS_THROUGHPUT },
1034: { NULL, -1 },
1035: };
1036:
1037: for (t = toskeywords; t->keyword != NULL; t++) {
1038: if (strcmp(s, t->keyword) == 0) {
1039: *val = t->val;
1040: return (1);
1041: }
1042: }
1.83 dtucker 1043:
1.102 haesbaer 1044: return (0);
1.108 haesbaer 1045: }
1046:
1047: void
1048: report_connect(const struct sockaddr *sa, socklen_t salen)
1049: {
1050: char remote_host[NI_MAXHOST];
1051: char remote_port[NI_MAXSERV];
1052: int herr;
1053: int flags = NI_NUMERICSERV;
1054:
1055: if (nflag)
1056: flags |= NI_NUMERICHOST;
1057:
1058: if ((herr = getnameinfo(sa, salen,
1059: remote_host, sizeof(remote_host),
1060: remote_port, sizeof(remote_port),
1061: flags)) != 0) {
1062: if (herr == EAI_SYSTEM)
1063: err(1, "getnameinfo");
1064: else
1065: errx(1, "getnameinfo: %s", gai_strerror(herr));
1066: }
1067:
1068: fprintf(stderr,
1069: "Connection from %s %s "
1070: "received!\n", remote_host, remote_port);
1.7 deraadt 1071: }
1.1 deraadt 1072:
1.11 ericj 1073: void
1.58 deraadt 1074: help(void)
1.1 deraadt 1075: {
1.21 ericj 1076: usage(0);
1077: fprintf(stderr, "\tCommand Summary:\n\
1078: \t-4 Use IPv4\n\
1079: \t-6 Use IPv6\n\
1.73 markus 1080: \t-D Enable the debug socket option\n\
1.69 tedu 1081: \t-d Detach from stdin\n\
1.114 jmc 1082: \t-F Pass socket fd\n\
1.21 ericj 1083: \t-h This help text\n\
1.90 djm 1084: \t-I length TCP receive buffer length\n\
1.21 ericj 1085: \t-i secs\t Delay interval for lines sent, ports scanned\n\
1086: \t-k Keep inbound sockets open for multiple connects\n\
1087: \t-l Listen mode, for inbound connects\n\
1.111 sthen 1088: \t-N Shutdown the network socket after EOF on stdin\n\
1.22 jasoni 1089: \t-n Suppress name/port resolutions\n\
1.90 djm 1090: \t-O length TCP send buffer length\n\
1.86 djm 1091: \t-P proxyuser\tUsername for proxy authentication\n\
1.36 jakob 1092: \t-p port\t Specify local port for remote connects\n\
1.21 ericj 1093: \t-r Randomize remote ports\n\
1.67 jmc 1094: \t-S Enable the TCP MD5 signature option\n\
1.21 ericj 1095: \t-s addr\t Local source address\n\
1.102 haesbaer 1096: \t-T toskeyword\tSet IP Type of Service\n\
1.21 ericj 1097: \t-t Answer TELNET negotiation\n\
1.67 jmc 1098: \t-U Use UNIX domain socket\n\
1.21 ericj 1099: \t-u UDP mode\n\
1.98 guenther 1100: \t-V rtable Specify alternate routing table\n\
1.21 ericj 1101: \t-v Verbose\n\
1102: \t-w secs\t Timeout for connects and final net reads\n\
1.75 djm 1103: \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\
1104: \t-x addr[:port]\tSpecify proxy address and port\n\
1.21 ericj 1105: \t-z Zero-I/O mode [used for scanning]\n\
1106: Port numbers can be individual or ranges: lo-hi [inclusive]\n");
1107: exit(1);
1.11 ericj 1108: }
1109:
1110: void
1.37 jakob 1111: usage(int ret)
1.11 ericj 1112: {
1.92 sobrado 1113: fprintf(stderr,
1.114 jmc 1114: "usage: nc [-46DdFhklNnrStUuvz] [-I length] [-i interval] [-O length]\n"
1.100 jeremy 1115: "\t [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n"
1.98 guenther 1116: "\t [-V rtable] [-w timeout] [-X proxy_protocol]\n"
1.100 jeremy 1117: "\t [-x proxy_address[:port]] [destination] [port]\n");
1.21 ericj 1118: if (ret)
1119: exit(1);
1.7 deraadt 1120: }
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