1 /* $OpenBSD: netcat.c,v 1.130 2015/07/26 19:12:28 chl Exp $ */ 2 /* 3 * Copyright (c) 2001 Eric Jackson <ericj@monkey.org> 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 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. 16 * 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 * 28 * $FreeBSD$ 29 */ 30 31 /* 32 * Re-written nc(1) for OpenBSD. Original implementation by 33 * *Hobbit* <hobbit@avian.org>. 34 */ 35 36 #include <errno.h> 37 #include <stdio.h> 38 #include <sys/arb.h> 39 #include <sys/limits.h> 40 #include <sys/types.h> 41 #include <sys/sbuf.h> 42 #include <sys/socket.h> 43 #include <sys/sysctl.h> 44 #include <sys/qmath.h> 45 #include <sys/stats.h> 46 #include <sys/time.h> 47 #include <sys/uio.h> 48 #include <sys/un.h> 49 50 #include <netinet/in.h> 51 #ifdef IPSEC 52 #include <netipsec/ipsec.h> 53 #endif 54 #include <netinet/tcp.h> 55 #include <netinet/ip.h> 56 #include <arpa/telnet.h> 57 58 #include <err.h> 59 #include <getopt.h> 60 #include <fcntl.h> 61 #include <limits.h> 62 #include <netdb.h> 63 #include <poll.h> 64 #include <signal.h> 65 #include <stdarg.h> 66 #include <stdlib.h> 67 #include <string.h> 68 #include <unistd.h> 69 #include "atomicio.h" 70 71 #ifndef SUN_LEN 72 #define SUN_LEN(su) \ 73 (sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path)) 74 #endif 75 76 #define PORT_MAX 65535 77 #define PORT_MAX_LEN 6 78 #define UNIX_DG_TMP_SOCKET_SIZE 19 79 80 #define POLL_STDIN 0 81 #define POLL_NETOUT 1 82 #define POLL_NETIN 2 83 #define POLL_STDOUT 3 84 #define BUFSIZE 16384 85 86 /* Command Line Options */ 87 int dflag; /* detached, no stdin */ 88 int Fflag; /* fdpass sock to stdout */ 89 unsigned int iflag; /* Interval Flag */ 90 int kflag; /* More than one connect */ 91 int lflag; /* Bind to local port */ 92 int FreeBSD_Mflag; /* Measure using stats(3) */ 93 int Nflag; /* shutdown() network socket */ 94 int nflag; /* Don't do name look up */ 95 int FreeBSD_Oflag; /* Do not use TCP options */ 96 char *Pflag; /* Proxy username */ 97 char *pflag; /* Localport flag */ 98 int rflag; /* Random ports flag */ 99 char *sflag; /* Source Address */ 100 int tflag; /* Telnet Emulation */ 101 int uflag; /* UDP - Default to TCP */ 102 int vflag; /* Verbosity */ 103 int xflag; /* Socks proxy */ 104 int zflag; /* Port Scan Flag */ 105 int Dflag; /* sodebug */ 106 int Iflag; /* TCP receive buffer size */ 107 int Oflag; /* TCP send buffer size */ 108 int Sflag; /* TCP MD5 signature option */ 109 int Tflag = -1; /* IP Type of Service */ 110 int rtableid = -1; 111 112 int timeout = -1; 113 int family = AF_UNSPEC; 114 char *portlist[PORT_MAX+1]; 115 char *unix_dg_tmp_socket; 116 117 void atelnet(int, unsigned char *, unsigned int); 118 void build_ports(char *); 119 void help(void); 120 int local_listen(char *, char *, struct addrinfo); 121 void readwrite(int); 122 void fdpass(int nfd) __attribute__((noreturn)); 123 int remote_connect(const char *, const char *, struct addrinfo); 124 int timeout_connect(int, const struct sockaddr *, socklen_t); 125 int socks_connect(const char *, const char *, struct addrinfo, 126 const char *, const char *, struct addrinfo, int, const char *); 127 int udptest(int); 128 int unix_bind(char *); 129 int unix_connect(char *); 130 int unix_listen(char *); 131 void FreeBSD_stats_setup(int); 132 void FreeBSD_stats_print(int); 133 void set_common_sockopts(int, int); 134 int map_tos(char *, int *); 135 void report_connect(const struct sockaddr *, socklen_t); 136 void usage(int); 137 ssize_t drainbuf(int, unsigned char *, size_t *); 138 ssize_t fillbuf(int, unsigned char *, size_t *); 139 140 #ifdef IPSEC 141 void add_ipsec_policy(int, int, char *); 142 143 char *ipsec_policy[2]; 144 #endif 145 146 int 147 main(int argc, char *argv[]) 148 { 149 int ch, s, ret, socksv, ipsec_count; 150 int numfibs; 151 size_t intsize = sizeof(int); 152 char *host, *uport; 153 struct addrinfo hints; 154 struct servent *sv; 155 socklen_t len; 156 struct sockaddr_storage cliaddr; 157 char *proxy; 158 const char *errstr, *proxyhost = "", *proxyport = NULL; 159 struct addrinfo proxyhints; 160 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE]; 161 struct option longopts[] = { 162 { "no-tcpopt", no_argument, &FreeBSD_Oflag, 1 }, 163 { NULL, 0, NULL, 0 } 164 }; 165 166 ret = 1; 167 ipsec_count = 0; 168 s = 0; 169 socksv = 5; 170 host = NULL; 171 uport = NULL; 172 sv = NULL; 173 174 signal(SIGPIPE, SIG_IGN); 175 176 while ((ch = getopt_long(argc, argv, 177 "46DdEe:FhI:i:klMNnoO:P:p:rSs:tT:UuV:vw:X:x:z", 178 longopts, NULL)) != -1) { 179 switch (ch) { 180 case '4': 181 family = AF_INET; 182 break; 183 case '6': 184 family = AF_INET6; 185 break; 186 case 'U': 187 family = AF_UNIX; 188 break; 189 case 'X': 190 if (strcasecmp(optarg, "connect") == 0) 191 socksv = -1; /* HTTP proxy CONNECT */ 192 else if (strcmp(optarg, "4") == 0) 193 socksv = 4; /* SOCKS v.4 */ 194 else if (strcmp(optarg, "5") == 0) 195 socksv = 5; /* SOCKS v.5 */ 196 else 197 errx(1, "unsupported proxy protocol"); 198 break; 199 case 'd': 200 dflag = 1; 201 break; 202 case 'e': 203 #ifdef IPSEC 204 ipsec_policy[ipsec_count++ % 2] = optarg; 205 #else 206 errx(1, "IPsec support unavailable."); 207 #endif 208 break; 209 case 'E': 210 #ifdef IPSEC 211 ipsec_policy[0] = "in ipsec esp/transport//require"; 212 ipsec_policy[1] = "out ipsec esp/transport//require"; 213 #else 214 errx(1, "IPsec support unavailable."); 215 #endif 216 break; 217 case 'F': 218 Fflag = 1; 219 break; 220 case 'h': 221 help(); 222 break; 223 case 'i': 224 iflag = strtonum(optarg, 0, UINT_MAX, &errstr); 225 if (errstr) 226 errx(1, "interval %s: %s", errstr, optarg); 227 break; 228 case 'k': 229 kflag = 1; 230 break; 231 case 'l': 232 lflag = 1; 233 break; 234 case 'M': 235 #ifndef WITH_STATS 236 errx(1, "-M requires stats(3) support"); 237 #else 238 FreeBSD_Mflag = 1; 239 #endif 240 break; 241 case 'N': 242 Nflag = 1; 243 break; 244 case 'n': 245 nflag = 1; 246 break; 247 case 'o': 248 fprintf(stderr, "option -o is deprecated.\n"); 249 break; 250 case 'P': 251 Pflag = optarg; 252 break; 253 case 'p': 254 pflag = optarg; 255 break; 256 case 'r': 257 rflag = 1; 258 break; 259 case 's': 260 sflag = optarg; 261 break; 262 case 't': 263 tflag = 1; 264 break; 265 case 'u': 266 uflag = 1; 267 break; 268 case 'V': 269 if (sysctlbyname("net.fibs", &numfibs, &intsize, NULL, 0) == -1) 270 errx(1, "Multiple FIBS not supported"); 271 rtableid = (int)strtonum(optarg, 0, 272 numfibs - 1, &errstr); 273 if (errstr) 274 errx(1, "rtable %s: %s", errstr, optarg); 275 break; 276 case 'v': 277 vflag = 1; 278 break; 279 case 'w': 280 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr); 281 if (errstr) 282 errx(1, "timeout %s: %s", errstr, optarg); 283 timeout *= 1000; 284 break; 285 case 'x': 286 xflag = 1; 287 if ((proxy = strdup(optarg)) == NULL) 288 err(1, NULL); 289 break; 290 case 'z': 291 zflag = 1; 292 break; 293 case 'D': 294 Dflag = 1; 295 break; 296 case 'I': 297 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr); 298 if (errstr != NULL) 299 errx(1, "TCP receive window %s: %s", 300 errstr, optarg); 301 break; 302 case 'O': 303 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr); 304 if (errstr != NULL) { 305 if (strcmp(errstr, "invalid") != 0) 306 errx(1, "TCP send window %s: %s", 307 errstr, optarg); 308 } 309 break; 310 case 'S': 311 Sflag = 1; 312 break; 313 case 'T': 314 errstr = NULL; 315 errno = 0; 316 if (map_tos(optarg, &Tflag)) 317 break; 318 if (strlen(optarg) > 1 && optarg[0] == '0' && 319 optarg[1] == 'x') 320 Tflag = (int)strtol(optarg, NULL, 16); 321 else 322 Tflag = (int)strtonum(optarg, 0, 255, 323 &errstr); 324 if (Tflag < 0 || Tflag > 255 || errstr || errno) 325 errx(1, "illegal tos value %s", optarg); 326 break; 327 default: 328 usage(1); 329 } 330 } 331 argc -= optind; 332 argv += optind; 333 334 /* Cruft to make sure options are clean, and used properly. */ 335 if (argv[0] && !argv[1] && family == AF_UNIX) { 336 host = argv[0]; 337 uport = NULL; 338 } else if (argv[0] && !argv[1]) { 339 if (!lflag) 340 usage(1); 341 uport = argv[0]; 342 host = NULL; 343 } else if (argv[0] && argv[1]) { 344 host = argv[0]; 345 uport = argv[1]; 346 } else 347 usage(1); 348 349 if (lflag && sflag) 350 errx(1, "cannot use -s and -l"); 351 if (lflag && pflag) 352 errx(1, "cannot use -p and -l"); 353 if (lflag && zflag) 354 errx(1, "cannot use -z and -l"); 355 if (!lflag && kflag) 356 errx(1, "must use -l with -k"); 357 358 /* Get name of temporary socket for unix datagram client */ 359 if ((family == AF_UNIX) && uflag && !lflag) { 360 if (sflag) { 361 unix_dg_tmp_socket = sflag; 362 } else { 363 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX", 364 UNIX_DG_TMP_SOCKET_SIZE); 365 if (mktemp(unix_dg_tmp_socket_buf) == NULL) 366 err(1, "mktemp"); 367 unix_dg_tmp_socket = unix_dg_tmp_socket_buf; 368 } 369 } 370 371 /* Initialize addrinfo structure. */ 372 if (family != AF_UNIX) { 373 memset(&hints, 0, sizeof(struct addrinfo)); 374 hints.ai_family = family; 375 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 376 hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 377 if (nflag) 378 hints.ai_flags |= AI_NUMERICHOST; 379 } 380 381 if (xflag) { 382 if (uflag) 383 errx(1, "no proxy support for UDP mode"); 384 385 if (lflag) 386 errx(1, "no proxy support for listen"); 387 388 if (family == AF_UNIX) 389 errx(1, "no proxy support for unix sockets"); 390 391 /* XXX IPv6 transport to proxy would probably work */ 392 if (family == AF_INET6) 393 errx(1, "no proxy support for IPv6"); 394 395 if (sflag) 396 errx(1, "no proxy support for local source address"); 397 398 proxyhost = strsep(&proxy, ":"); 399 proxyport = proxy; 400 401 memset(&proxyhints, 0, sizeof(struct addrinfo)); 402 proxyhints.ai_family = family; 403 proxyhints.ai_socktype = SOCK_STREAM; 404 proxyhints.ai_protocol = IPPROTO_TCP; 405 if (nflag) 406 proxyhints.ai_flags |= AI_NUMERICHOST; 407 } 408 409 if (lflag) { 410 int connfd; 411 ret = 0; 412 413 if (family == AF_UNIX) { 414 if (uflag) 415 s = unix_bind(host); 416 else 417 s = unix_listen(host); 418 } 419 420 /* Allow only one connection at a time, but stay alive. */ 421 for (;;) { 422 if (family != AF_UNIX) 423 s = local_listen(host, uport, hints); 424 if (s < 0) 425 err(1, NULL); 426 /* 427 * For UDP and -k, don't connect the socket, let it 428 * receive datagrams from multiple socket pairs. 429 */ 430 if (uflag && kflag) 431 readwrite(s); 432 /* 433 * For UDP and not -k, we will use recvfrom() initially 434 * to wait for a caller, then use the regular functions 435 * to talk to the caller. 436 */ 437 else if (uflag && !kflag) { 438 int rv, plen; 439 char buf[16384]; 440 struct sockaddr_storage z; 441 442 len = sizeof(z); 443 plen = 2048; 444 rv = recvfrom(s, buf, plen, MSG_PEEK, 445 (struct sockaddr *)&z, &len); 446 if (rv < 0) 447 err(1, "recvfrom"); 448 449 rv = connect(s, (struct sockaddr *)&z, len); 450 if (rv < 0) 451 err(1, "connect"); 452 453 if (vflag) 454 report_connect((struct sockaddr *)&z, len); 455 456 readwrite(s); 457 } else { 458 len = sizeof(cliaddr); 459 connfd = accept(s, (struct sockaddr *)&cliaddr, 460 &len); 461 if (connfd == -1) { 462 /* For now, all errnos are fatal */ 463 err(1, "accept"); 464 } 465 if (vflag) 466 report_connect((struct sockaddr *)&cliaddr, len); 467 468 if (FreeBSD_Mflag) 469 FreeBSD_stats_setup(connfd); 470 readwrite(connfd); 471 close(connfd); 472 } 473 474 if (family != AF_UNIX) 475 close(s); 476 else if (uflag) { 477 if (connect(s, NULL, 0) < 0) 478 err(1, "connect"); 479 } 480 481 if (!kflag) 482 break; 483 } 484 } else if (family == AF_UNIX) { 485 ret = 0; 486 487 if ((s = unix_connect(host)) > 0 && !zflag) { 488 readwrite(s); 489 close(s); 490 } else 491 ret = 1; 492 493 if (uflag) 494 unlink(unix_dg_tmp_socket); 495 exit(ret); 496 497 } else { 498 int i = 0; 499 500 /* Construct the portlist[] array. */ 501 build_ports(uport); 502 503 /* Cycle through portlist, connecting to each port. */ 504 for (i = 0; portlist[i] != NULL; i++) { 505 if (s) 506 close(s); 507 508 if (xflag) 509 s = socks_connect(host, portlist[i], hints, 510 proxyhost, proxyport, proxyhints, socksv, 511 Pflag); 512 else 513 s = remote_connect(host, portlist[i], hints); 514 515 if (s < 0) 516 continue; 517 518 ret = 0; 519 if (vflag || zflag) { 520 /* For UDP, make sure we are connected. */ 521 if (uflag) { 522 if (udptest(s) == -1) { 523 ret = 1; 524 continue; 525 } 526 } 527 528 /* Don't look up port if -n. */ 529 if (nflag) 530 sv = NULL; 531 else { 532 sv = getservbyport( 533 ntohs(atoi(portlist[i])), 534 uflag ? "udp" : "tcp"); 535 } 536 537 fprintf(stderr, 538 "Connection to %s %s port [%s/%s] " 539 "succeeded!\n", host, portlist[i], 540 uflag ? "udp" : "tcp", 541 sv ? sv->s_name : "*"); 542 } 543 if (Fflag) 544 fdpass(s); 545 else if (!zflag) 546 readwrite(s); 547 } 548 } 549 550 if (s) 551 close(s); 552 553 exit(ret); 554 } 555 556 /* 557 * unix_bind() 558 * Returns a unix socket bound to the given path 559 */ 560 int 561 unix_bind(char *path) 562 { 563 struct sockaddr_un sun; 564 int s; 565 566 /* Create unix domain socket. */ 567 if ((s = socket(AF_UNIX, uflag ? SOCK_DGRAM : SOCK_STREAM, 568 0)) < 0) 569 return (-1); 570 571 memset(&sun, 0, sizeof(struct sockaddr_un)); 572 sun.sun_family = AF_UNIX; 573 574 if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >= 575 sizeof(sun.sun_path)) { 576 close(s); 577 errno = ENAMETOOLONG; 578 return (-1); 579 } 580 581 if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) { 582 close(s); 583 return (-1); 584 } 585 return (s); 586 } 587 588 /* 589 * unix_connect() 590 * Returns a socket connected to a local unix socket. Returns -1 on failure. 591 */ 592 int 593 unix_connect(char *path) 594 { 595 struct sockaddr_un sun; 596 int s; 597 598 if (uflag) { 599 if ((s = unix_bind(unix_dg_tmp_socket)) < 0) 600 return (-1); 601 } else { 602 if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) 603 return (-1); 604 } 605 (void)fcntl(s, F_SETFD, FD_CLOEXEC); 606 607 memset(&sun, 0, sizeof(struct sockaddr_un)); 608 sun.sun_family = AF_UNIX; 609 610 if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >= 611 sizeof(sun.sun_path)) { 612 close(s); 613 errno = ENAMETOOLONG; 614 return (-1); 615 } 616 if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) { 617 close(s); 618 return (-1); 619 } 620 return (s); 621 622 } 623 624 /* 625 * unix_listen() 626 * Create a unix domain socket, and listen on it. 627 */ 628 int 629 unix_listen(char *path) 630 { 631 int s; 632 if ((s = unix_bind(path)) < 0) 633 return (-1); 634 635 if (listen(s, 5) < 0) { 636 close(s); 637 return (-1); 638 } 639 return (s); 640 } 641 642 /* 643 * remote_connect() 644 * Returns a socket connected to a remote host. Properly binds to a local 645 * port or source address if needed. Returns -1 on failure. 646 */ 647 int 648 remote_connect(const char *host, const char *port, struct addrinfo hints) 649 { 650 struct addrinfo *res, *res0; 651 int s, error, on = 1; 652 653 if ((error = getaddrinfo(host, port, &hints, &res))) 654 errx(1, "getaddrinfo: %s", gai_strerror(error)); 655 656 res0 = res; 657 do { 658 if ((s = socket(res0->ai_family, res0->ai_socktype, 659 res0->ai_protocol)) < 0) 660 continue; 661 662 if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_SETFIB, 663 &rtableid, sizeof(rtableid)) == -1)) 664 err(1, "setsockopt SO_SETFIB"); 665 666 /* Bind to a local port or source address if specified. */ 667 if (sflag || pflag) { 668 struct addrinfo ahints, *ares; 669 670 /* try IP_BINDANY, but don't insist */ 671 setsockopt(s, IPPROTO_IP, IP_BINDANY, &on, sizeof(on)); 672 memset(&ahints, 0, sizeof(struct addrinfo)); 673 ahints.ai_family = res0->ai_family; 674 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 675 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 676 ahints.ai_flags = AI_PASSIVE; 677 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares))) 678 errx(1, "getaddrinfo: %s", gai_strerror(error)); 679 680 if (bind(s, (struct sockaddr *)ares->ai_addr, 681 ares->ai_addrlen) < 0) 682 err(1, "bind failed"); 683 freeaddrinfo(ares); 684 } 685 686 set_common_sockopts(s, res0->ai_family); 687 688 if (timeout_connect(s, res0->ai_addr, res0->ai_addrlen) == 0) 689 break; 690 else if (vflag) 691 warn("connect to %s port %s (%s) failed", host, port, 692 uflag ? "udp" : "tcp"); 693 694 close(s); 695 s = -1; 696 } while ((res0 = res0->ai_next) != NULL); 697 698 freeaddrinfo(res); 699 700 return (s); 701 } 702 703 int 704 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen) 705 { 706 struct pollfd pfd; 707 socklen_t optlen; 708 int flags, optval; 709 int ret; 710 711 if (timeout != -1) { 712 flags = fcntl(s, F_GETFL, 0); 713 if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1) 714 err(1, "set non-blocking mode"); 715 } 716 717 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) { 718 pfd.fd = s; 719 pfd.events = POLLOUT; 720 if ((ret = poll(&pfd, 1, timeout)) == 1) { 721 optlen = sizeof(optval); 722 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR, 723 &optval, &optlen)) == 0) { 724 errno = optval; 725 ret = optval == 0 ? 0 : -1; 726 } 727 } else if (ret == 0) { 728 errno = ETIMEDOUT; 729 ret = -1; 730 } else 731 err(1, "poll failed"); 732 } 733 734 if (timeout != -1 && fcntl(s, F_SETFL, flags) == -1) 735 err(1, "restoring flags"); 736 737 return (ret); 738 } 739 740 /* 741 * local_listen() 742 * Returns a socket listening on a local port, binds to specified source 743 * address. Returns -1 on failure. 744 */ 745 int 746 local_listen(char *host, char *port, struct addrinfo hints) 747 { 748 struct addrinfo *res, *res0; 749 int s, ret, x = 1; 750 int error; 751 752 /* Allow nodename to be null. */ 753 hints.ai_flags |= AI_PASSIVE; 754 755 /* 756 * In the case of binding to a wildcard address 757 * default to binding to an ipv4 address. 758 */ 759 if (host == NULL && hints.ai_family == AF_UNSPEC) 760 hints.ai_family = AF_INET; 761 762 if ((error = getaddrinfo(host, port, &hints, &res))) 763 errx(1, "getaddrinfo: %s", gai_strerror(error)); 764 765 res0 = res; 766 do { 767 if ((s = socket(res0->ai_family, res0->ai_socktype, 768 res0->ai_protocol)) < 0) 769 continue; 770 771 if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_SETFIB, 772 &rtableid, sizeof(rtableid)) == -1)) 773 err(1, "setsockopt SO_SETFIB"); 774 775 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x)); 776 if (ret == -1) 777 err(1, NULL); 778 779 if (FreeBSD_Oflag) { 780 if (setsockopt(s, IPPROTO_TCP, TCP_NOOPT, 781 &FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1) 782 err(1, "disable TCP options"); 783 } 784 785 set_common_sockopts(s, res0->ai_family); 786 787 if (bind(s, (struct sockaddr *)res0->ai_addr, 788 res0->ai_addrlen) == 0) 789 break; 790 791 close(s); 792 s = -1; 793 } while ((res0 = res0->ai_next) != NULL); 794 795 if (!uflag && s != -1) { 796 if (listen(s, 1) < 0) 797 err(1, "listen"); 798 } 799 800 freeaddrinfo(res); 801 802 return (s); 803 } 804 805 /* 806 * readwrite() 807 * Loop that polls on the network file descriptor and stdin. 808 */ 809 void 810 readwrite(int net_fd) 811 { 812 struct pollfd pfd[4]; 813 int stdin_fd = STDIN_FILENO; 814 int stdout_fd = STDOUT_FILENO; 815 unsigned char netinbuf[BUFSIZE]; 816 size_t netinbufpos = 0; 817 unsigned char stdinbuf[BUFSIZE]; 818 size_t stdinbufpos = 0; 819 int n, num_fds; 820 int stats_printed = 0; 821 ssize_t ret; 822 823 /* don't read from stdin if requested */ 824 if (dflag) 825 stdin_fd = -1; 826 827 /* stdin */ 828 pfd[POLL_STDIN].fd = stdin_fd; 829 pfd[POLL_STDIN].events = POLLIN; 830 831 /* network out */ 832 pfd[POLL_NETOUT].fd = net_fd; 833 pfd[POLL_NETOUT].events = 0; 834 835 /* network in */ 836 pfd[POLL_NETIN].fd = net_fd; 837 pfd[POLL_NETIN].events = POLLIN; 838 839 /* stdout */ 840 pfd[POLL_STDOUT].fd = stdout_fd; 841 pfd[POLL_STDOUT].events = 0; 842 843 while (1) { 844 /* both inputs are gone, buffers are empty, we are done */ 845 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 846 && stdinbufpos == 0 && netinbufpos == 0) { 847 if (FreeBSD_Mflag && !stats_printed) 848 FreeBSD_stats_print(net_fd); 849 close(net_fd); 850 return; 851 } 852 /* both outputs are gone, we can't continue */ 853 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) { 854 if (FreeBSD_Mflag && !stats_printed) 855 FreeBSD_stats_print(net_fd); 856 close(net_fd); 857 return; 858 } 859 /* listen and net in gone, queues empty, done */ 860 if (lflag && pfd[POLL_NETIN].fd == -1 861 && stdinbufpos == 0 && netinbufpos == 0) { 862 if (FreeBSD_Mflag && !stats_printed) 863 FreeBSD_stats_print(net_fd); 864 close(net_fd); 865 return; 866 } 867 868 /* help says -i is for "wait between lines sent". We read and 869 * write arbitrary amounts of data, and we don't want to start 870 * scanning for newlines, so this is as good as it gets */ 871 if (iflag) 872 sleep(iflag); 873 874 /* poll */ 875 num_fds = poll(pfd, 4, timeout); 876 877 /* treat poll errors */ 878 if (num_fds == -1) { 879 close(net_fd); 880 err(1, "polling error"); 881 } 882 883 /* timeout happened */ 884 if (num_fds == 0) { 885 if (FreeBSD_Mflag) 886 FreeBSD_stats_print(net_fd); 887 return; 888 } 889 890 /* treat socket error conditions */ 891 for (n = 0; n < 4; n++) { 892 if (pfd[n].revents & (POLLERR|POLLNVAL)) { 893 pfd[n].fd = -1; 894 } 895 } 896 /* reading is possible after HUP */ 897 if (pfd[POLL_STDIN].events & POLLIN && 898 pfd[POLL_STDIN].revents & POLLHUP && 899 ! (pfd[POLL_STDIN].revents & POLLIN)) 900 pfd[POLL_STDIN].fd = -1; 901 902 if (pfd[POLL_NETIN].events & POLLIN && 903 pfd[POLL_NETIN].revents & POLLHUP && 904 ! (pfd[POLL_NETIN].revents & POLLIN)) 905 pfd[POLL_NETIN].fd = -1; 906 907 if (pfd[POLL_NETOUT].revents & POLLHUP) { 908 if (Nflag) 909 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 910 pfd[POLL_NETOUT].fd = -1; 911 } 912 /* if HUP, stop watching stdout */ 913 if (pfd[POLL_STDOUT].revents & POLLHUP) 914 pfd[POLL_STDOUT].fd = -1; 915 /* if no net out, stop watching stdin */ 916 if (pfd[POLL_NETOUT].fd == -1) 917 pfd[POLL_STDIN].fd = -1; 918 /* if no stdout, stop watching net in */ 919 if (pfd[POLL_STDOUT].fd == -1) { 920 if (pfd[POLL_NETIN].fd != -1) 921 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 922 pfd[POLL_NETIN].fd = -1; 923 } 924 925 /* try to read from stdin */ 926 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) { 927 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf, 928 &stdinbufpos); 929 /* error or eof on stdin - remove from pfd */ 930 if (ret == 0 || ret == -1) 931 pfd[POLL_STDIN].fd = -1; 932 /* read something - poll net out */ 933 if (stdinbufpos > 0) 934 pfd[POLL_NETOUT].events = POLLOUT; 935 /* filled buffer - remove self from polling */ 936 if (stdinbufpos == BUFSIZE) 937 pfd[POLL_STDIN].events = 0; 938 } 939 /* try to write to network */ 940 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) { 941 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf, 942 &stdinbufpos); 943 if (ret == -1) 944 pfd[POLL_NETOUT].fd = -1; 945 /* buffer empty - remove self from polling */ 946 if (stdinbufpos == 0) 947 pfd[POLL_NETOUT].events = 0; 948 /* buffer no longer full - poll stdin again */ 949 if (stdinbufpos < BUFSIZE) 950 pfd[POLL_STDIN].events = POLLIN; 951 } 952 /* try to read from network */ 953 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) { 954 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf, 955 &netinbufpos); 956 if (ret == -1) 957 pfd[POLL_NETIN].fd = -1; 958 /* eof on net in - remove from pfd */ 959 if (ret == 0) { 960 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 961 pfd[POLL_NETIN].fd = -1; 962 } 963 /* read something - poll stdout */ 964 if (netinbufpos > 0) 965 pfd[POLL_STDOUT].events = POLLOUT; 966 /* filled buffer - remove self from polling */ 967 if (netinbufpos == BUFSIZE) 968 pfd[POLL_NETIN].events = 0; 969 /* handle telnet */ 970 if (tflag) 971 atelnet(pfd[POLL_NETIN].fd, netinbuf, 972 netinbufpos); 973 } 974 /* try to write to stdout */ 975 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) { 976 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf, 977 &netinbufpos); 978 if (ret == -1) 979 pfd[POLL_STDOUT].fd = -1; 980 /* buffer empty - remove self from polling */ 981 if (netinbufpos == 0) 982 pfd[POLL_STDOUT].events = 0; 983 /* buffer no longer full - poll net in again */ 984 if (netinbufpos < BUFSIZE) 985 pfd[POLL_NETIN].events = POLLIN; 986 } 987 988 /* stdin gone and queue empty? */ 989 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) { 990 if (pfd[POLL_NETOUT].fd != -1 && Nflag) { 991 if (FreeBSD_Mflag) { 992 FreeBSD_stats_print(net_fd); 993 stats_printed = 1; 994 } 995 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 996 } 997 pfd[POLL_NETOUT].fd = -1; 998 } 999 /* net in gone and queue empty? */ 1000 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) { 1001 pfd[POLL_STDOUT].fd = -1; 1002 } 1003 } 1004 } 1005 1006 ssize_t 1007 drainbuf(int fd, unsigned char *buf, size_t *bufpos) 1008 { 1009 ssize_t n; 1010 ssize_t adjust; 1011 1012 n = write(fd, buf, *bufpos); 1013 /* don't treat EAGAIN, EINTR as error */ 1014 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1015 n = -2; 1016 if (n <= 0) 1017 return n; 1018 /* adjust buffer */ 1019 adjust = *bufpos - n; 1020 if (adjust > 0) 1021 memmove(buf, buf + n, adjust); 1022 *bufpos -= n; 1023 return n; 1024 } 1025 1026 1027 ssize_t 1028 fillbuf(int fd, unsigned char *buf, size_t *bufpos) 1029 { 1030 size_t num = BUFSIZE - *bufpos; 1031 ssize_t n; 1032 1033 n = read(fd, buf + *bufpos, num); 1034 /* don't treat EAGAIN, EINTR as error */ 1035 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1036 n = -2; 1037 if (n <= 0) 1038 return n; 1039 *bufpos += n; 1040 return n; 1041 } 1042 1043 /* 1044 * fdpass() 1045 * Pass the connected file descriptor to stdout and exit. 1046 */ 1047 void 1048 fdpass(int nfd) 1049 { 1050 struct msghdr mh; 1051 union { 1052 struct cmsghdr hdr; 1053 char buf[CMSG_SPACE(sizeof(int))]; 1054 } cmsgbuf; 1055 struct cmsghdr *cmsg; 1056 struct iovec iov; 1057 char c = '\0'; 1058 ssize_t r; 1059 struct pollfd pfd; 1060 1061 /* Avoid obvious stupidity */ 1062 if (isatty(STDOUT_FILENO)) 1063 errx(1, "Cannot pass file descriptor to tty"); 1064 1065 bzero(&mh, sizeof(mh)); 1066 bzero(&cmsgbuf, sizeof(cmsgbuf)); 1067 bzero(&iov, sizeof(iov)); 1068 1069 mh.msg_control = (caddr_t)&cmsgbuf.buf; 1070 mh.msg_controllen = sizeof(cmsgbuf.buf); 1071 cmsg = CMSG_FIRSTHDR(&mh); 1072 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 1073 cmsg->cmsg_level = SOL_SOCKET; 1074 cmsg->cmsg_type = SCM_RIGHTS; 1075 *(int *)CMSG_DATA(cmsg) = nfd; 1076 1077 iov.iov_base = &c; 1078 iov.iov_len = 1; 1079 mh.msg_iov = &iov; 1080 mh.msg_iovlen = 1; 1081 1082 bzero(&pfd, sizeof(pfd)); 1083 pfd.fd = STDOUT_FILENO; 1084 pfd.events = POLLOUT; 1085 for (;;) { 1086 r = sendmsg(STDOUT_FILENO, &mh, 0); 1087 if (r == -1) { 1088 if (errno == EAGAIN || errno == EINTR) { 1089 if (poll(&pfd, 1, -1) == -1) 1090 err(1, "poll"); 1091 continue; 1092 } 1093 err(1, "sendmsg"); 1094 } else if (r != 1) 1095 errx(1, "sendmsg: unexpected return value %zd", r); 1096 else 1097 break; 1098 } 1099 exit(0); 1100 } 1101 1102 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */ 1103 void 1104 atelnet(int nfd, unsigned char *buf, unsigned int size) 1105 { 1106 unsigned char *p, *end; 1107 unsigned char obuf[4]; 1108 1109 if (size < 3) 1110 return; 1111 end = buf + size - 2; 1112 1113 for (p = buf; p < end; p++) { 1114 if (*p != IAC) 1115 continue; 1116 1117 obuf[0] = IAC; 1118 p++; 1119 if ((*p == WILL) || (*p == WONT)) 1120 obuf[1] = DONT; 1121 else if ((*p == DO) || (*p == DONT)) 1122 obuf[1] = WONT; 1123 else 1124 continue; 1125 1126 p++; 1127 obuf[2] = *p; 1128 if (atomicio(vwrite, nfd, obuf, 3) != 3) 1129 warn("Write Error!"); 1130 } 1131 } 1132 1133 /* 1134 * build_ports() 1135 * Build an array of ports in portlist[], listing each port 1136 * that we should try to connect to. 1137 */ 1138 void 1139 build_ports(char *p) 1140 { 1141 const char *errstr; 1142 char *n; 1143 int hi, lo, cp; 1144 int x = 0; 1145 1146 if ((n = strchr(p, '-')) != NULL) { 1147 *n = '\0'; 1148 n++; 1149 1150 /* Make sure the ports are in order: lowest->highest. */ 1151 hi = strtonum(n, 1, PORT_MAX, &errstr); 1152 if (errstr) 1153 errx(1, "port number %s: %s", errstr, n); 1154 lo = strtonum(p, 1, PORT_MAX, &errstr); 1155 if (errstr) 1156 errx(1, "port number %s: %s", errstr, p); 1157 1158 if (lo > hi) { 1159 cp = hi; 1160 hi = lo; 1161 lo = cp; 1162 } 1163 1164 /* Load ports sequentially. */ 1165 for (cp = lo; cp <= hi; cp++) { 1166 portlist[x] = calloc(1, PORT_MAX_LEN); 1167 if (portlist[x] == NULL) 1168 err(1, NULL); 1169 snprintf(portlist[x], PORT_MAX_LEN, "%d", cp); 1170 x++; 1171 } 1172 1173 /* Randomly swap ports. */ 1174 if (rflag) { 1175 int y; 1176 char *c; 1177 1178 for (x = 0; x <= (hi - lo); x++) { 1179 y = (arc4random() & 0xFFFF) % (hi - lo); 1180 c = portlist[x]; 1181 portlist[x] = portlist[y]; 1182 portlist[y] = c; 1183 } 1184 } 1185 } else { 1186 hi = strtonum(p, 1, PORT_MAX, &errstr); 1187 if (errstr) 1188 errx(1, "port number %s: %s", errstr, p); 1189 portlist[0] = strdup(p); 1190 if (portlist[0] == NULL) 1191 err(1, NULL); 1192 } 1193 } 1194 1195 /* 1196 * udptest() 1197 * Do a few writes to see if the UDP port is there. 1198 * Fails once PF state table is full. 1199 */ 1200 int 1201 udptest(int s) 1202 { 1203 int i, ret; 1204 1205 for (i = 0; i <= 3; i++) { 1206 if (write(s, "X", 1) == 1) 1207 ret = 1; 1208 else 1209 ret = -1; 1210 } 1211 return (ret); 1212 } 1213 1214 void 1215 FreeBSD_stats_setup(int s) 1216 { 1217 1218 if (setsockopt(s, IPPROTO_TCP, TCP_STATS, 1219 &FreeBSD_Mflag, sizeof(FreeBSD_Mflag)) == -1) { 1220 if (errno == EOPNOTSUPP) { 1221 warnx("getsockopt(TCP_STATS) failed; " 1222 "kernel built without \"options STATS\"?"); 1223 } 1224 err(1, "enable TCP_STATS gathering"); 1225 } 1226 } 1227 1228 void 1229 FreeBSD_stats_print(int s) 1230 { 1231 #ifdef WITH_STATS 1232 struct statsblob *statsb; 1233 struct sbuf *sb; 1234 socklen_t sockoptlen; 1235 int error; 1236 1237 /* 1238 * This usleep is a workaround for TCP_STATS reporting 1239 * incorrect values for TXPB. 1240 */ 1241 usleep(100000); 1242 1243 sockoptlen = 2048; 1244 statsb = malloc(sockoptlen); 1245 if (statsb == NULL) 1246 err(1, "malloc"); 1247 error = getsockopt(s, IPPROTO_TCP, TCP_STATS, statsb, &sockoptlen); 1248 if (error != 0) { 1249 if (errno == EOVERFLOW && statsb->cursz > sockoptlen) { 1250 /* Retry with a larger size. */ 1251 sockoptlen = statsb->cursz; 1252 statsb = realloc(statsb, sockoptlen); 1253 if (statsb == NULL) 1254 err(1, "realloc"); 1255 error = getsockopt(s, IPPROTO_TCP, TCP_STATS, 1256 statsb, &sockoptlen); 1257 } 1258 if (error != 0) 1259 err(1, "getsockopt"); 1260 } 1261 1262 sb = sbuf_new_auto(); 1263 error = stats_blob_tostr(statsb, sb, SB_STRFMT_JSON, SB_TOSTR_META); 1264 if (error != 0) 1265 errc(1, error, "stats_blob_tostr"); 1266 1267 error = sbuf_finish(sb); 1268 if (error != 0) 1269 err(1, "sbuf_finish"); 1270 1271 fprintf(stderr, "%s\n", sbuf_data(sb)); 1272 #endif 1273 } 1274 1275 void 1276 set_common_sockopts(int s, int af) 1277 { 1278 int x = 1; 1279 1280 if (Sflag) { 1281 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG, 1282 &x, sizeof(x)) == -1) 1283 err(1, NULL); 1284 } 1285 if (Dflag) { 1286 if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 1287 &x, sizeof(x)) == -1) 1288 err(1, NULL); 1289 } 1290 if (Tflag != -1) { 1291 int proto, option; 1292 1293 if (af == AF_INET6) { 1294 proto = IPPROTO_IPV6; 1295 option = IPV6_TCLASS; 1296 } else { 1297 proto = IPPROTO_IP; 1298 option = IP_TOS; 1299 } 1300 1301 if (setsockopt(s, proto, option, &Tflag, sizeof(Tflag)) == -1) 1302 err(1, "set IP ToS"); 1303 } 1304 if (Iflag) { 1305 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, 1306 &Iflag, sizeof(Iflag)) == -1) 1307 err(1, "set TCP receive buffer size"); 1308 } 1309 if (Oflag) { 1310 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, 1311 &Oflag, sizeof(Oflag)) == -1) 1312 err(1, "set TCP send buffer size"); 1313 } 1314 if (FreeBSD_Oflag) { 1315 if (setsockopt(s, IPPROTO_TCP, TCP_NOOPT, 1316 &FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1) 1317 err(1, "disable TCP options"); 1318 } 1319 if (FreeBSD_Mflag) 1320 FreeBSD_stats_setup(s); 1321 #ifdef IPSEC 1322 if (ipsec_policy[0] != NULL) 1323 add_ipsec_policy(s, af, ipsec_policy[0]); 1324 if (ipsec_policy[1] != NULL) 1325 add_ipsec_policy(s, af, ipsec_policy[1]); 1326 #endif 1327 } 1328 1329 int 1330 map_tos(char *s, int *val) 1331 { 1332 /* DiffServ Codepoints and other TOS mappings */ 1333 const struct toskeywords { 1334 const char *keyword; 1335 int val; 1336 } *t, toskeywords[] = { 1337 { "af11", IPTOS_DSCP_AF11 }, 1338 { "af12", IPTOS_DSCP_AF12 }, 1339 { "af13", IPTOS_DSCP_AF13 }, 1340 { "af21", IPTOS_DSCP_AF21 }, 1341 { "af22", IPTOS_DSCP_AF22 }, 1342 { "af23", IPTOS_DSCP_AF23 }, 1343 { "af31", IPTOS_DSCP_AF31 }, 1344 { "af32", IPTOS_DSCP_AF32 }, 1345 { "af33", IPTOS_DSCP_AF33 }, 1346 { "af41", IPTOS_DSCP_AF41 }, 1347 { "af42", IPTOS_DSCP_AF42 }, 1348 { "af43", IPTOS_DSCP_AF43 }, 1349 { "critical", IPTOS_PREC_CRITIC_ECP }, 1350 { "cs0", IPTOS_DSCP_CS0 }, 1351 { "cs1", IPTOS_DSCP_CS1 }, 1352 { "cs2", IPTOS_DSCP_CS2 }, 1353 { "cs3", IPTOS_DSCP_CS3 }, 1354 { "cs4", IPTOS_DSCP_CS4 }, 1355 { "cs5", IPTOS_DSCP_CS5 }, 1356 { "cs6", IPTOS_DSCP_CS6 }, 1357 { "cs7", IPTOS_DSCP_CS7 }, 1358 { "ef", IPTOS_DSCP_EF }, 1359 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL }, 1360 { "lowdelay", IPTOS_LOWDELAY }, 1361 { "netcontrol", IPTOS_PREC_NETCONTROL }, 1362 { "reliability", IPTOS_RELIABILITY }, 1363 { "throughput", IPTOS_THROUGHPUT }, 1364 { NULL, -1 }, 1365 }; 1366 1367 for (t = toskeywords; t->keyword != NULL; t++) { 1368 if (strcmp(s, t->keyword) == 0) { 1369 *val = t->val; 1370 return (1); 1371 } 1372 } 1373 1374 return (0); 1375 } 1376 1377 void 1378 report_connect(const struct sockaddr *sa, socklen_t salen) 1379 { 1380 char remote_host[NI_MAXHOST]; 1381 char remote_port[NI_MAXSERV]; 1382 int herr; 1383 int flags = NI_NUMERICSERV; 1384 1385 if (nflag) 1386 flags |= NI_NUMERICHOST; 1387 1388 if ((herr = getnameinfo(sa, salen, 1389 remote_host, sizeof(remote_host), 1390 remote_port, sizeof(remote_port), 1391 flags)) != 0) { 1392 if (herr == EAI_SYSTEM) 1393 err(1, "getnameinfo"); 1394 else 1395 errx(1, "getnameinfo: %s", gai_strerror(herr)); 1396 } 1397 1398 fprintf(stderr, 1399 "Connection from %s %s " 1400 "received!\n", remote_host, remote_port); 1401 } 1402 1403 void 1404 help(void) 1405 { 1406 usage(0); 1407 fprintf(stderr, "\tCommand Summary:\n\ 1408 \t-4 Use IPv4\n\ 1409 \t-6 Use IPv6\n\ 1410 \t-D Enable the debug socket option\n\ 1411 \t-d Detach from stdin\n"); 1412 #ifdef IPSEC 1413 fprintf(stderr, "\ 1414 \t-E Use IPsec ESP\n\ 1415 \t-e policy Use specified IPsec policy\n"); 1416 #endif 1417 fprintf(stderr, "\ 1418 \t-F Pass socket fd\n\ 1419 \t-h This help text\n\ 1420 \t-I length TCP receive buffer length\n\ 1421 \t-i secs\t Delay interval for lines sent, ports scanned\n\ 1422 \t-k Keep inbound sockets open for multiple connects\n\ 1423 \t-l Listen mode, for inbound connects\n\ 1424 \t-N Shutdown the network socket after EOF on stdin\n\ 1425 \t-n Suppress name/port resolutions\n\ 1426 \t--no-tcpopt Disable TCP options\n\ 1427 \t-O length TCP send buffer length\n\ 1428 \t-P proxyuser\tUsername for proxy authentication\n\ 1429 \t-p port\t Specify local port for remote connects\n\ 1430 \t-r Randomize remote ports\n\ 1431 \t-S Enable the TCP MD5 signature option\n\ 1432 \t-s addr\t Local source address\n\ 1433 \t-T toskeyword\tSet IP Type of Service\n\ 1434 \t-t Answer TELNET negotiation\n\ 1435 \t-U Use UNIX domain socket\n\ 1436 \t-u UDP mode\n\ 1437 \t-V rtable Specify alternate routing table\n\ 1438 \t-v Verbose\n\ 1439 \t-w secs\t Timeout for connects and final net reads\n\ 1440 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\ 1441 \t-x addr[:port]\tSpecify proxy address and port\n\ 1442 \t-z Zero-I/O mode [used for scanning]\n\ 1443 Port numbers can be individual or ranges: lo-hi [inclusive]\n"); 1444 #ifdef IPSEC 1445 fprintf(stderr, "See ipsec_set_policy(3) for -e argument format\n"); 1446 #endif 1447 exit(1); 1448 } 1449 1450 #ifdef IPSEC 1451 void 1452 add_ipsec_policy(int s, int af, char *policy) 1453 { 1454 char *raw; 1455 int e; 1456 1457 raw = ipsec_set_policy(policy, strlen(policy)); 1458 if (raw == NULL) 1459 errx(1, "ipsec_set_policy `%s': %s", policy, 1460 ipsec_strerror()); 1461 if (af == AF_INET) 1462 e = setsockopt(s, IPPROTO_IP, IP_IPSEC_POLICY, raw, 1463 ipsec_get_policylen(raw)); 1464 if (af == AF_INET6) 1465 e = setsockopt(s, IPPROTO_IPV6, IPV6_IPSEC_POLICY, raw, 1466 ipsec_get_policylen(raw)); 1467 if (e < 0) 1468 err(1, "ipsec policy cannot be configured"); 1469 free(raw); 1470 if (vflag) 1471 fprintf(stderr, "ipsec policy configured: `%s'\n", policy); 1472 return; 1473 } 1474 #endif /* IPSEC */ 1475 1476 void 1477 usage(int ret) 1478 { 1479 fprintf(stderr, 1480 #ifdef IPSEC 1481 "usage: nc [-46DdEFhklNnrStUuvz] [-e policy] [-I length] [-i interval] [-O length]\n" 1482 #else 1483 "usage: nc [-46DdFhklNnrStUuvz] [-I length] [-i interval] [-O length]\n" 1484 #endif 1485 "\t [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n" 1486 "\t [-V rtable] [-w timeout] [-X proxy_protocol]\n" 1487 "\t [-x proxy_address[:port]] [destination] [port]\n"); 1488 if (ret) 1489 exit(1); 1490 } 1491