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 int FreeBSD_sctp; /* Use SCTP */ 97 char *Pflag; /* Proxy username */ 98 char *pflag; /* Localport flag */ 99 int rflag; /* Random ports flag */ 100 char *sflag; /* Source Address */ 101 int tflag; /* Telnet Emulation */ 102 int uflag; /* UDP - Default to TCP */ 103 int vflag; /* Verbosity */ 104 int xflag; /* Socks proxy */ 105 int zflag; /* Port Scan Flag */ 106 int Dflag; /* sodebug */ 107 int Iflag; /* TCP receive buffer size */ 108 int Oflag; /* TCP send buffer size */ 109 int Sflag; /* TCP MD5 signature option */ 110 int Tflag = -1; /* IP Type of Service */ 111 int rtableid = -1; 112 113 int timeout = -1; 114 int family = AF_UNSPEC; 115 char *portlist[PORT_MAX+1]; 116 char *unix_dg_tmp_socket; 117 118 void atelnet(int, unsigned char *, unsigned int); 119 void build_ports(char *); 120 void help(void); 121 int local_listen(char *, char *, struct addrinfo); 122 void readwrite(int); 123 void fdpass(int nfd) __attribute__((noreturn)); 124 int remote_connect(const char *, const char *, struct addrinfo); 125 int timeout_connect(int, const struct sockaddr *, socklen_t); 126 int socks_connect(const char *, const char *, struct addrinfo, 127 const char *, const char *, struct addrinfo, int, const char *); 128 int udptest(int); 129 int unix_bind(char *); 130 int unix_connect(char *); 131 int unix_listen(char *); 132 void FreeBSD_stats_setup(int); 133 void FreeBSD_stats_print(int); 134 void set_common_sockopts(int, int); 135 int map_tos(char *, int *); 136 void report_connect(const struct sockaddr *, socklen_t); 137 void usage(int); 138 ssize_t drainbuf(int, unsigned char *, size_t *); 139 ssize_t fillbuf(int, unsigned char *, size_t *); 140 141 #ifdef IPSEC 142 void add_ipsec_policy(int, int, char *); 143 144 char *ipsec_policy[2]; 145 #endif 146 147 int 148 main(int argc, char *argv[]) 149 { 150 int ch, s, ret, socksv, ipsec_count; 151 int numfibs; 152 size_t intsize = sizeof(int); 153 char *host, *uport; 154 struct addrinfo hints; 155 struct servent *sv; 156 socklen_t len; 157 struct sockaddr_storage cliaddr; 158 char *proxy; 159 const char *errstr, *proxyhost = "", *proxyport = NULL; 160 struct addrinfo proxyhints; 161 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE]; 162 struct option longopts[] = { 163 { "no-tcpopt", no_argument, &FreeBSD_Oflag, 1 }, 164 { "sctp", no_argument, &FreeBSD_sctp, 1 }, 165 { NULL, 0, NULL, 0 } 166 }; 167 168 ret = 1; 169 ipsec_count = 0; 170 s = 0; 171 socksv = 5; 172 host = NULL; 173 uport = NULL; 174 sv = NULL; 175 176 signal(SIGPIPE, SIG_IGN); 177 178 while ((ch = getopt_long(argc, argv, 179 "46DdEe:FhI:i:klMNnoO:P:p:rSs:tT:UuV:vw:X:x:z", 180 longopts, NULL)) != -1) { 181 switch (ch) { 182 case '4': 183 family = AF_INET; 184 break; 185 case '6': 186 family = AF_INET6; 187 break; 188 case 'U': 189 family = AF_UNIX; 190 break; 191 case 'X': 192 if (strcasecmp(optarg, "connect") == 0) 193 socksv = -1; /* HTTP proxy CONNECT */ 194 else if (strcmp(optarg, "4") == 0) 195 socksv = 4; /* SOCKS v.4 */ 196 else if (strcmp(optarg, "5") == 0) 197 socksv = 5; /* SOCKS v.5 */ 198 else 199 errx(1, "unsupported proxy protocol"); 200 break; 201 case 'd': 202 dflag = 1; 203 break; 204 case 'e': 205 #ifdef IPSEC 206 ipsec_policy[ipsec_count++ % 2] = optarg; 207 #else 208 errx(1, "IPsec support unavailable."); 209 #endif 210 break; 211 case 'E': 212 #ifdef IPSEC 213 ipsec_policy[0] = "in ipsec esp/transport//require"; 214 ipsec_policy[1] = "out ipsec esp/transport//require"; 215 #else 216 errx(1, "IPsec support unavailable."); 217 #endif 218 break; 219 case 'F': 220 Fflag = 1; 221 break; 222 case 'h': 223 help(); 224 break; 225 case 'i': 226 iflag = strtonum(optarg, 0, UINT_MAX, &errstr); 227 if (errstr) 228 errx(1, "interval %s: %s", errstr, optarg); 229 break; 230 case 'k': 231 kflag = 1; 232 break; 233 case 'l': 234 lflag = 1; 235 break; 236 case 'M': 237 #ifndef WITH_STATS 238 errx(1, "-M requires stats(3) support"); 239 #else 240 FreeBSD_Mflag = 1; 241 #endif 242 break; 243 case 'N': 244 Nflag = 1; 245 break; 246 case 'n': 247 nflag = 1; 248 break; 249 case 'o': 250 fprintf(stderr, "option -o is deprecated.\n"); 251 break; 252 case 'P': 253 Pflag = optarg; 254 break; 255 case 'p': 256 pflag = optarg; 257 break; 258 case 'r': 259 rflag = 1; 260 break; 261 case 's': 262 sflag = optarg; 263 break; 264 case 't': 265 tflag = 1; 266 break; 267 case 'u': 268 uflag = 1; 269 break; 270 case 'V': 271 if (sysctlbyname("net.fibs", &numfibs, &intsize, NULL, 0) == -1) 272 errx(1, "Multiple FIBS not supported"); 273 rtableid = (int)strtonum(optarg, 0, 274 numfibs - 1, &errstr); 275 if (errstr) 276 errx(1, "rtable %s: %s", errstr, optarg); 277 break; 278 case 'v': 279 vflag = 1; 280 break; 281 case 'w': 282 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr); 283 if (errstr) 284 errx(1, "timeout %s: %s", errstr, optarg); 285 timeout *= 1000; 286 break; 287 case 'x': 288 xflag = 1; 289 if ((proxy = strdup(optarg)) == NULL) 290 err(1, NULL); 291 break; 292 case 'z': 293 zflag = 1; 294 break; 295 case 'D': 296 Dflag = 1; 297 break; 298 case 'I': 299 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr); 300 if (errstr != NULL) 301 errx(1, "TCP receive window %s: %s", 302 errstr, optarg); 303 break; 304 case 'O': 305 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr); 306 if (errstr != NULL) { 307 if (strcmp(errstr, "invalid") != 0) 308 errx(1, "TCP send window %s: %s", 309 errstr, optarg); 310 } 311 break; 312 case 'S': 313 Sflag = 1; 314 break; 315 case 'T': 316 errstr = NULL; 317 errno = 0; 318 if (map_tos(optarg, &Tflag)) 319 break; 320 if (strlen(optarg) > 1 && optarg[0] == '0' && 321 optarg[1] == 'x') 322 Tflag = (int)strtol(optarg, NULL, 16); 323 else 324 Tflag = (int)strtonum(optarg, 0, 255, 325 &errstr); 326 if (Tflag < 0 || Tflag > 255 || errstr || errno) 327 errx(1, "illegal tos value %s", optarg); 328 break; 329 case 0: 330 /* Long option. */ 331 break; 332 default: 333 usage(1); 334 } 335 } 336 argc -= optind; 337 argv += optind; 338 339 /* Cruft to make sure options are clean, and used properly. */ 340 if (argv[0] && !argv[1] && family == AF_UNIX) { 341 host = argv[0]; 342 uport = NULL; 343 } else if (argv[0] && !argv[1]) { 344 if (!lflag) 345 usage(1); 346 uport = argv[0]; 347 host = NULL; 348 } else if (argv[0] && argv[1]) { 349 host = argv[0]; 350 uport = argv[1]; 351 } else 352 usage(1); 353 354 if (lflag && sflag) 355 errx(1, "cannot use -s and -l"); 356 if (lflag && pflag) 357 errx(1, "cannot use -p and -l"); 358 if (lflag && zflag) 359 errx(1, "cannot use -z and -l"); 360 if (!lflag && kflag) 361 errx(1, "must use -l with -k"); 362 if (FreeBSD_sctp) { 363 if (uflag) 364 errx(1, "cannot use -u and --sctp"); 365 if (family == AF_UNIX) 366 errx(1, "cannot use -U and --sctp"); 367 } 368 369 /* Get name of temporary socket for unix datagram client */ 370 if ((family == AF_UNIX) && uflag && !lflag) { 371 if (sflag) { 372 unix_dg_tmp_socket = sflag; 373 } else { 374 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX", 375 UNIX_DG_TMP_SOCKET_SIZE); 376 if (mktemp(unix_dg_tmp_socket_buf) == NULL) 377 err(1, "mktemp"); 378 unix_dg_tmp_socket = unix_dg_tmp_socket_buf; 379 } 380 } 381 382 /* Initialize addrinfo structure. */ 383 if (family != AF_UNIX) { 384 memset(&hints, 0, sizeof(struct addrinfo)); 385 hints.ai_family = family; 386 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 387 hints.ai_protocol = uflag ? IPPROTO_UDP : 388 FreeBSD_sctp ? IPPROTO_SCTP : IPPROTO_TCP; 389 if (nflag) 390 hints.ai_flags |= AI_NUMERICHOST; 391 } 392 393 if (xflag) { 394 if (uflag) 395 errx(1, "no proxy support for UDP mode"); 396 397 if (FreeBSD_sctp) 398 errx(1, "no proxy support for SCTP mode"); 399 400 if (lflag) 401 errx(1, "no proxy support for listen"); 402 403 if (family == AF_UNIX) 404 errx(1, "no proxy support for unix sockets"); 405 406 /* XXX IPv6 transport to proxy would probably work */ 407 if (family == AF_INET6) 408 errx(1, "no proxy support for IPv6"); 409 410 if (sflag) 411 errx(1, "no proxy support for local source address"); 412 413 proxyhost = strsep(&proxy, ":"); 414 proxyport = proxy; 415 416 memset(&proxyhints, 0, sizeof(struct addrinfo)); 417 proxyhints.ai_family = family; 418 proxyhints.ai_socktype = SOCK_STREAM; 419 proxyhints.ai_protocol = IPPROTO_TCP; 420 if (nflag) 421 proxyhints.ai_flags |= AI_NUMERICHOST; 422 } 423 424 if (lflag) { 425 int connfd; 426 ret = 0; 427 428 if (family == AF_UNIX) { 429 if (uflag) 430 s = unix_bind(host); 431 else 432 s = unix_listen(host); 433 } 434 435 /* Allow only one connection at a time, but stay alive. */ 436 for (;;) { 437 if (family != AF_UNIX) 438 s = local_listen(host, uport, hints); 439 if (s < 0) 440 err(1, NULL); 441 /* 442 * For UDP and -k, don't connect the socket, let it 443 * receive datagrams from multiple socket pairs. 444 */ 445 if (uflag && kflag) 446 readwrite(s); 447 /* 448 * For UDP and not -k, we will use recvfrom() initially 449 * to wait for a caller, then use the regular functions 450 * to talk to the caller. 451 */ 452 else if (uflag && !kflag) { 453 int rv, plen; 454 char buf[16384]; 455 struct sockaddr_storage z; 456 457 len = sizeof(z); 458 plen = 2048; 459 rv = recvfrom(s, buf, plen, MSG_PEEK, 460 (struct sockaddr *)&z, &len); 461 if (rv < 0) 462 err(1, "recvfrom"); 463 464 rv = connect(s, (struct sockaddr *)&z, len); 465 if (rv < 0) 466 err(1, "connect"); 467 468 if (vflag) 469 report_connect((struct sockaddr *)&z, len); 470 471 readwrite(s); 472 } else { 473 len = sizeof(cliaddr); 474 connfd = accept(s, (struct sockaddr *)&cliaddr, 475 &len); 476 if (connfd == -1) { 477 /* For now, all errnos are fatal */ 478 err(1, "accept"); 479 } 480 if (vflag) 481 report_connect((struct sockaddr *)&cliaddr, len); 482 483 if (FreeBSD_Mflag) 484 FreeBSD_stats_setup(connfd); 485 readwrite(connfd); 486 close(connfd); 487 } 488 489 if (family != AF_UNIX) 490 close(s); 491 else if (uflag) { 492 if (connect(s, NULL, 0) < 0) 493 err(1, "connect"); 494 } 495 496 if (!kflag) 497 break; 498 } 499 } else if (family == AF_UNIX) { 500 ret = 0; 501 502 if ((s = unix_connect(host)) > 0 && !zflag) { 503 readwrite(s); 504 close(s); 505 } else 506 ret = 1; 507 508 if (uflag) 509 unlink(unix_dg_tmp_socket); 510 exit(ret); 511 512 } else { 513 int i = 0; 514 515 /* Construct the portlist[] array. */ 516 build_ports(uport); 517 518 /* Cycle through portlist, connecting to each port. */ 519 for (i = 0; portlist[i] != NULL; i++) { 520 if (s) 521 close(s); 522 523 if (xflag) 524 s = socks_connect(host, portlist[i], hints, 525 proxyhost, proxyport, proxyhints, socksv, 526 Pflag); 527 else 528 s = remote_connect(host, portlist[i], hints); 529 530 if (s < 0) 531 continue; 532 533 ret = 0; 534 if (vflag || zflag) { 535 /* For UDP, make sure we are connected. */ 536 if (uflag) { 537 if (udptest(s) == -1) { 538 ret = 1; 539 continue; 540 } 541 } 542 543 /* Don't look up port if -n. */ 544 if (nflag) 545 sv = NULL; 546 else { 547 sv = getservbyport( 548 ntohs(atoi(portlist[i])), 549 uflag ? "udp" : "tcp"); 550 } 551 552 fprintf(stderr, 553 "Connection to %s %s port [%s/%s] " 554 "succeeded!\n", host, portlist[i], 555 uflag ? "udp" : "tcp", 556 sv ? sv->s_name : "*"); 557 } 558 if (Fflag) 559 fdpass(s); 560 else if (!zflag) 561 readwrite(s); 562 } 563 } 564 565 if (s) 566 close(s); 567 568 exit(ret); 569 } 570 571 /* 572 * unix_bind() 573 * Returns a unix socket bound to the given path 574 */ 575 int 576 unix_bind(char *path) 577 { 578 struct sockaddr_un sun; 579 int s; 580 581 /* Create unix domain socket. */ 582 if ((s = socket(AF_UNIX, uflag ? SOCK_DGRAM : SOCK_STREAM, 583 0)) < 0) 584 return (-1); 585 586 memset(&sun, 0, sizeof(struct sockaddr_un)); 587 sun.sun_family = AF_UNIX; 588 589 if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >= 590 sizeof(sun.sun_path)) { 591 close(s); 592 errno = ENAMETOOLONG; 593 return (-1); 594 } 595 596 if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) { 597 close(s); 598 return (-1); 599 } 600 return (s); 601 } 602 603 /* 604 * unix_connect() 605 * Returns a socket connected to a local unix socket. Returns -1 on failure. 606 */ 607 int 608 unix_connect(char *path) 609 { 610 struct sockaddr_un sun; 611 int s; 612 613 if (uflag) { 614 if ((s = unix_bind(unix_dg_tmp_socket)) < 0) 615 return (-1); 616 } else { 617 if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) 618 return (-1); 619 } 620 (void)fcntl(s, F_SETFD, FD_CLOEXEC); 621 622 memset(&sun, 0, sizeof(struct sockaddr_un)); 623 sun.sun_family = AF_UNIX; 624 625 if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >= 626 sizeof(sun.sun_path)) { 627 close(s); 628 errno = ENAMETOOLONG; 629 return (-1); 630 } 631 if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) { 632 close(s); 633 return (-1); 634 } 635 return (s); 636 637 } 638 639 /* 640 * unix_listen() 641 * Create a unix domain socket, and listen on it. 642 */ 643 int 644 unix_listen(char *path) 645 { 646 int s; 647 if ((s = unix_bind(path)) < 0) 648 return (-1); 649 650 if (listen(s, 5) < 0) { 651 close(s); 652 return (-1); 653 } 654 return (s); 655 } 656 657 /* 658 * remote_connect() 659 * Returns a socket connected to a remote host. Properly binds to a local 660 * port or source address if needed. Returns -1 on failure. 661 */ 662 int 663 remote_connect(const char *host, const char *port, struct addrinfo hints) 664 { 665 struct addrinfo *res, *res0; 666 int s, error, on = 1; 667 668 if ((error = getaddrinfo(host, port, &hints, &res))) 669 errx(1, "getaddrinfo: %s", gai_strerror(error)); 670 671 res0 = res; 672 do { 673 if ((s = socket(res0->ai_family, res0->ai_socktype, 674 res0->ai_protocol)) < 0) 675 continue; 676 677 if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_SETFIB, 678 &rtableid, sizeof(rtableid)) == -1)) 679 err(1, "setsockopt SO_SETFIB"); 680 681 /* Bind to a local port or source address if specified. */ 682 if (sflag || pflag) { 683 struct addrinfo ahints, *ares; 684 685 /* try IP_BINDANY, but don't insist */ 686 setsockopt(s, IPPROTO_IP, IP_BINDANY, &on, sizeof(on)); 687 memset(&ahints, 0, sizeof(struct addrinfo)); 688 ahints.ai_family = res0->ai_family; 689 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 690 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 691 ahints.ai_flags = AI_PASSIVE; 692 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares))) 693 errx(1, "getaddrinfo: %s", gai_strerror(error)); 694 695 if (bind(s, (struct sockaddr *)ares->ai_addr, 696 ares->ai_addrlen) < 0) 697 err(1, "bind failed"); 698 freeaddrinfo(ares); 699 } 700 701 set_common_sockopts(s, res0->ai_family); 702 703 if (timeout_connect(s, res0->ai_addr, res0->ai_addrlen) == 0) 704 break; 705 else if (vflag) 706 warn("connect to %s port %s (%s) failed", host, port, 707 uflag ? "udp" : "tcp"); 708 709 close(s); 710 s = -1; 711 } while ((res0 = res0->ai_next) != NULL); 712 713 freeaddrinfo(res); 714 715 return (s); 716 } 717 718 int 719 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen) 720 { 721 struct pollfd pfd; 722 socklen_t optlen; 723 int flags, optval; 724 int ret; 725 726 if (timeout != -1) { 727 flags = fcntl(s, F_GETFL, 0); 728 if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1) 729 err(1, "set non-blocking mode"); 730 } 731 732 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) { 733 pfd.fd = s; 734 pfd.events = POLLOUT; 735 if ((ret = poll(&pfd, 1, timeout)) == 1) { 736 optlen = sizeof(optval); 737 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR, 738 &optval, &optlen)) == 0) { 739 errno = optval; 740 ret = optval == 0 ? 0 : -1; 741 } 742 } else if (ret == 0) { 743 errno = ETIMEDOUT; 744 ret = -1; 745 } else 746 err(1, "poll failed"); 747 } 748 749 if (timeout != -1 && fcntl(s, F_SETFL, flags) == -1) 750 err(1, "restoring flags"); 751 752 return (ret); 753 } 754 755 /* 756 * local_listen() 757 * Returns a socket listening on a local port, binds to specified source 758 * address. Returns -1 on failure. 759 */ 760 int 761 local_listen(char *host, char *port, struct addrinfo hints) 762 { 763 struct addrinfo *res, *res0; 764 int s, ret, x = 1; 765 int error; 766 767 /* Allow nodename to be null. */ 768 hints.ai_flags |= AI_PASSIVE; 769 770 /* 771 * In the case of binding to a wildcard address 772 * default to binding to an ipv4 address. 773 */ 774 if (host == NULL && hints.ai_family == AF_UNSPEC) 775 hints.ai_family = AF_INET; 776 777 if ((error = getaddrinfo(host, port, &hints, &res))) 778 errx(1, "getaddrinfo: %s", gai_strerror(error)); 779 780 res0 = res; 781 do { 782 if ((s = socket(res0->ai_family, res0->ai_socktype, 783 res0->ai_protocol)) < 0) 784 continue; 785 786 if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_SETFIB, 787 &rtableid, sizeof(rtableid)) == -1)) 788 err(1, "setsockopt SO_SETFIB"); 789 790 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x)); 791 if (ret == -1) 792 err(1, NULL); 793 794 if (FreeBSD_Oflag) { 795 if (setsockopt(s, IPPROTO_TCP, TCP_NOOPT, 796 &FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1) 797 err(1, "disable TCP options"); 798 } 799 800 set_common_sockopts(s, res0->ai_family); 801 802 if (bind(s, (struct sockaddr *)res0->ai_addr, 803 res0->ai_addrlen) == 0) 804 break; 805 806 close(s); 807 s = -1; 808 } while ((res0 = res0->ai_next) != NULL); 809 810 if (!uflag && s != -1) { 811 if (listen(s, 1) < 0) 812 err(1, "listen"); 813 } 814 815 freeaddrinfo(res); 816 817 return (s); 818 } 819 820 /* 821 * readwrite() 822 * Loop that polls on the network file descriptor and stdin. 823 */ 824 void 825 readwrite(int net_fd) 826 { 827 struct pollfd pfd[4]; 828 int stdin_fd = STDIN_FILENO; 829 int stdout_fd = STDOUT_FILENO; 830 unsigned char netinbuf[BUFSIZE]; 831 size_t netinbufpos = 0; 832 unsigned char stdinbuf[BUFSIZE]; 833 size_t stdinbufpos = 0; 834 int n, num_fds; 835 int stats_printed = 0; 836 ssize_t ret; 837 838 /* don't read from stdin if requested */ 839 if (dflag) 840 stdin_fd = -1; 841 842 /* stdin */ 843 pfd[POLL_STDIN].fd = stdin_fd; 844 pfd[POLL_STDIN].events = POLLIN; 845 846 /* network out */ 847 pfd[POLL_NETOUT].fd = net_fd; 848 pfd[POLL_NETOUT].events = 0; 849 850 /* network in */ 851 pfd[POLL_NETIN].fd = net_fd; 852 pfd[POLL_NETIN].events = POLLIN; 853 854 /* stdout */ 855 pfd[POLL_STDOUT].fd = stdout_fd; 856 pfd[POLL_STDOUT].events = 0; 857 858 while (1) { 859 /* both inputs are gone, buffers are empty, we are done */ 860 if (pfd[POLL_STDIN].fd == -1 && 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 /* both outputs are gone, we can't continue */ 868 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) { 869 if (FreeBSD_Mflag && !stats_printed) 870 FreeBSD_stats_print(net_fd); 871 close(net_fd); 872 return; 873 } 874 /* listen and net in gone, queues empty, done */ 875 if (lflag && pfd[POLL_NETIN].fd == -1 876 && stdinbufpos == 0 && netinbufpos == 0) { 877 if (FreeBSD_Mflag && !stats_printed) 878 FreeBSD_stats_print(net_fd); 879 close(net_fd); 880 return; 881 } 882 883 /* help says -i is for "wait between lines sent". We read and 884 * write arbitrary amounts of data, and we don't want to start 885 * scanning for newlines, so this is as good as it gets */ 886 if (iflag) 887 sleep(iflag); 888 889 /* poll */ 890 num_fds = poll(pfd, 4, timeout); 891 892 /* treat poll errors */ 893 if (num_fds == -1) { 894 close(net_fd); 895 err(1, "polling error"); 896 } 897 898 /* timeout happened */ 899 if (num_fds == 0) { 900 if (FreeBSD_Mflag) 901 FreeBSD_stats_print(net_fd); 902 return; 903 } 904 905 /* treat socket error conditions */ 906 for (n = 0; n < 4; n++) { 907 if (pfd[n].revents & (POLLERR|POLLNVAL)) { 908 pfd[n].fd = -1; 909 } 910 } 911 /* reading is possible after HUP */ 912 if (pfd[POLL_STDIN].events & POLLIN && 913 pfd[POLL_STDIN].revents & POLLHUP && 914 ! (pfd[POLL_STDIN].revents & POLLIN)) 915 pfd[POLL_STDIN].fd = -1; 916 917 if (pfd[POLL_NETIN].events & POLLIN && 918 pfd[POLL_NETIN].revents & POLLHUP && 919 ! (pfd[POLL_NETIN].revents & POLLIN)) 920 pfd[POLL_NETIN].fd = -1; 921 922 if (pfd[POLL_NETOUT].revents & POLLHUP) { 923 if (Nflag) 924 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 925 pfd[POLL_NETOUT].fd = -1; 926 } 927 /* if HUP, stop watching stdout */ 928 if (pfd[POLL_STDOUT].revents & POLLHUP) 929 pfd[POLL_STDOUT].fd = -1; 930 /* if no net out, stop watching stdin */ 931 if (pfd[POLL_NETOUT].fd == -1) 932 pfd[POLL_STDIN].fd = -1; 933 /* if no stdout, stop watching net in */ 934 if (pfd[POLL_STDOUT].fd == -1) { 935 if (pfd[POLL_NETIN].fd != -1) 936 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 937 pfd[POLL_NETIN].fd = -1; 938 } 939 940 /* try to read from stdin */ 941 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) { 942 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf, 943 &stdinbufpos); 944 /* error or eof on stdin - remove from pfd */ 945 if (ret == 0 || ret == -1) 946 pfd[POLL_STDIN].fd = -1; 947 /* read something - poll net out */ 948 if (stdinbufpos > 0) 949 pfd[POLL_NETOUT].events = POLLOUT; 950 /* filled buffer - remove self from polling */ 951 if (stdinbufpos == BUFSIZE) 952 pfd[POLL_STDIN].events = 0; 953 } 954 /* try to write to network */ 955 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) { 956 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf, 957 &stdinbufpos); 958 if (ret == -1) 959 pfd[POLL_NETOUT].fd = -1; 960 /* buffer empty - remove self from polling */ 961 if (stdinbufpos == 0) 962 pfd[POLL_NETOUT].events = 0; 963 /* buffer no longer full - poll stdin again */ 964 if (stdinbufpos < BUFSIZE) 965 pfd[POLL_STDIN].events = POLLIN; 966 } 967 /* try to read from network */ 968 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) { 969 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf, 970 &netinbufpos); 971 if (ret == -1) 972 pfd[POLL_NETIN].fd = -1; 973 /* eof on net in - remove from pfd */ 974 if (ret == 0) { 975 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 976 pfd[POLL_NETIN].fd = -1; 977 } 978 /* read something - poll stdout */ 979 if (netinbufpos > 0) 980 pfd[POLL_STDOUT].events = POLLOUT; 981 /* filled buffer - remove self from polling */ 982 if (netinbufpos == BUFSIZE) 983 pfd[POLL_NETIN].events = 0; 984 /* handle telnet */ 985 if (tflag) 986 atelnet(pfd[POLL_NETIN].fd, netinbuf, 987 netinbufpos); 988 } 989 /* try to write to stdout */ 990 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) { 991 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf, 992 &netinbufpos); 993 if (ret == -1) 994 pfd[POLL_STDOUT].fd = -1; 995 /* buffer empty - remove self from polling */ 996 if (netinbufpos == 0) 997 pfd[POLL_STDOUT].events = 0; 998 /* buffer no longer full - poll net in again */ 999 if (netinbufpos < BUFSIZE) 1000 pfd[POLL_NETIN].events = POLLIN; 1001 } 1002 1003 /* stdin gone and queue empty? */ 1004 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) { 1005 if (pfd[POLL_NETOUT].fd != -1 && Nflag) { 1006 if (FreeBSD_Mflag) { 1007 FreeBSD_stats_print(net_fd); 1008 stats_printed = 1; 1009 } 1010 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1011 } 1012 pfd[POLL_NETOUT].fd = -1; 1013 } 1014 /* net in gone and queue empty? */ 1015 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) { 1016 pfd[POLL_STDOUT].fd = -1; 1017 } 1018 } 1019 } 1020 1021 ssize_t 1022 drainbuf(int fd, unsigned char *buf, size_t *bufpos) 1023 { 1024 ssize_t n; 1025 ssize_t adjust; 1026 1027 n = write(fd, buf, *bufpos); 1028 /* don't treat EAGAIN, EINTR as error */ 1029 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1030 n = -2; 1031 if (n <= 0) 1032 return n; 1033 /* adjust buffer */ 1034 adjust = *bufpos - n; 1035 if (adjust > 0) 1036 memmove(buf, buf + n, adjust); 1037 *bufpos -= n; 1038 return n; 1039 } 1040 1041 1042 ssize_t 1043 fillbuf(int fd, unsigned char *buf, size_t *bufpos) 1044 { 1045 size_t num = BUFSIZE - *bufpos; 1046 ssize_t n; 1047 1048 n = read(fd, buf + *bufpos, num); 1049 /* don't treat EAGAIN, EINTR as error */ 1050 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1051 n = -2; 1052 if (n <= 0) 1053 return n; 1054 *bufpos += n; 1055 return n; 1056 } 1057 1058 /* 1059 * fdpass() 1060 * Pass the connected file descriptor to stdout and exit. 1061 */ 1062 void 1063 fdpass(int nfd) 1064 { 1065 struct msghdr mh; 1066 union { 1067 struct cmsghdr hdr; 1068 char buf[CMSG_SPACE(sizeof(int))]; 1069 } cmsgbuf; 1070 struct cmsghdr *cmsg; 1071 struct iovec iov; 1072 char c = '\0'; 1073 ssize_t r; 1074 struct pollfd pfd; 1075 1076 /* Avoid obvious stupidity */ 1077 if (isatty(STDOUT_FILENO)) 1078 errx(1, "Cannot pass file descriptor to tty"); 1079 1080 bzero(&mh, sizeof(mh)); 1081 bzero(&cmsgbuf, sizeof(cmsgbuf)); 1082 bzero(&iov, sizeof(iov)); 1083 1084 mh.msg_control = (caddr_t)&cmsgbuf.buf; 1085 mh.msg_controllen = sizeof(cmsgbuf.buf); 1086 cmsg = CMSG_FIRSTHDR(&mh); 1087 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 1088 cmsg->cmsg_level = SOL_SOCKET; 1089 cmsg->cmsg_type = SCM_RIGHTS; 1090 *(int *)CMSG_DATA(cmsg) = nfd; 1091 1092 iov.iov_base = &c; 1093 iov.iov_len = 1; 1094 mh.msg_iov = &iov; 1095 mh.msg_iovlen = 1; 1096 1097 bzero(&pfd, sizeof(pfd)); 1098 pfd.fd = STDOUT_FILENO; 1099 pfd.events = POLLOUT; 1100 for (;;) { 1101 r = sendmsg(STDOUT_FILENO, &mh, 0); 1102 if (r == -1) { 1103 if (errno == EAGAIN || errno == EINTR) { 1104 if (poll(&pfd, 1, -1) == -1) 1105 err(1, "poll"); 1106 continue; 1107 } 1108 err(1, "sendmsg"); 1109 } else if (r != 1) 1110 errx(1, "sendmsg: unexpected return value %zd", r); 1111 else 1112 break; 1113 } 1114 exit(0); 1115 } 1116 1117 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */ 1118 void 1119 atelnet(int nfd, unsigned char *buf, unsigned int size) 1120 { 1121 unsigned char *p, *end; 1122 unsigned char obuf[4]; 1123 1124 if (size < 3) 1125 return; 1126 end = buf + size - 2; 1127 1128 for (p = buf; p < end; p++) { 1129 if (*p != IAC) 1130 continue; 1131 1132 obuf[0] = IAC; 1133 p++; 1134 if ((*p == WILL) || (*p == WONT)) 1135 obuf[1] = DONT; 1136 else if ((*p == DO) || (*p == DONT)) 1137 obuf[1] = WONT; 1138 else 1139 continue; 1140 1141 p++; 1142 obuf[2] = *p; 1143 if (atomicio(vwrite, nfd, obuf, 3) != 3) 1144 warn("Write Error!"); 1145 } 1146 } 1147 1148 /* 1149 * build_ports() 1150 * Build an array of ports in portlist[], listing each port 1151 * that we should try to connect to. 1152 */ 1153 void 1154 build_ports(char *p) 1155 { 1156 const char *errstr; 1157 char *n; 1158 int hi, lo, cp; 1159 int x = 0; 1160 1161 if ((n = strchr(p, '-')) != NULL) { 1162 *n = '\0'; 1163 n++; 1164 1165 /* Make sure the ports are in order: lowest->highest. */ 1166 hi = strtonum(n, 1, PORT_MAX, &errstr); 1167 if (errstr) 1168 errx(1, "port number %s: %s", errstr, n); 1169 lo = strtonum(p, 1, PORT_MAX, &errstr); 1170 if (errstr) 1171 errx(1, "port number %s: %s", errstr, p); 1172 1173 if (lo > hi) { 1174 cp = hi; 1175 hi = lo; 1176 lo = cp; 1177 } 1178 1179 /* Load ports sequentially. */ 1180 for (cp = lo; cp <= hi; cp++) { 1181 portlist[x] = calloc(1, PORT_MAX_LEN); 1182 if (portlist[x] == NULL) 1183 err(1, NULL); 1184 snprintf(portlist[x], PORT_MAX_LEN, "%d", cp); 1185 x++; 1186 } 1187 1188 /* Randomly swap ports. */ 1189 if (rflag) { 1190 int y; 1191 char *c; 1192 1193 for (x = 0; x <= (hi - lo); x++) { 1194 y = (arc4random() & 0xFFFF) % (hi - lo); 1195 c = portlist[x]; 1196 portlist[x] = portlist[y]; 1197 portlist[y] = c; 1198 } 1199 } 1200 } else { 1201 hi = strtonum(p, 1, PORT_MAX, &errstr); 1202 if (errstr) 1203 errx(1, "port number %s: %s", errstr, p); 1204 portlist[0] = strdup(p); 1205 if (portlist[0] == NULL) 1206 err(1, NULL); 1207 } 1208 } 1209 1210 /* 1211 * udptest() 1212 * Do a few writes to see if the UDP port is there. 1213 * Fails once PF state table is full. 1214 */ 1215 int 1216 udptest(int s) 1217 { 1218 int i, ret; 1219 1220 for (i = 0; i <= 3; i++) { 1221 if (write(s, "X", 1) == 1) 1222 ret = 1; 1223 else 1224 ret = -1; 1225 } 1226 return (ret); 1227 } 1228 1229 void 1230 FreeBSD_stats_setup(int s) 1231 { 1232 1233 if (setsockopt(s, IPPROTO_TCP, TCP_STATS, 1234 &FreeBSD_Mflag, sizeof(FreeBSD_Mflag)) == -1) { 1235 if (errno == EOPNOTSUPP) { 1236 warnx("getsockopt(TCP_STATS) failed; " 1237 "kernel built without \"options STATS\"?"); 1238 } 1239 err(1, "enable TCP_STATS gathering"); 1240 } 1241 } 1242 1243 void 1244 FreeBSD_stats_print(int s) 1245 { 1246 #ifdef WITH_STATS 1247 struct statsblob *statsb; 1248 struct sbuf *sb; 1249 socklen_t sockoptlen; 1250 int error; 1251 1252 /* 1253 * This usleep is a workaround for TCP_STATS reporting 1254 * incorrect values for TXPB. 1255 */ 1256 usleep(100000); 1257 1258 sockoptlen = 2048; 1259 statsb = malloc(sockoptlen); 1260 if (statsb == NULL) 1261 err(1, "malloc"); 1262 error = getsockopt(s, IPPROTO_TCP, TCP_STATS, statsb, &sockoptlen); 1263 if (error != 0) { 1264 if (errno == EOVERFLOW && statsb->cursz > sockoptlen) { 1265 /* Retry with a larger size. */ 1266 sockoptlen = statsb->cursz; 1267 statsb = realloc(statsb, sockoptlen); 1268 if (statsb == NULL) 1269 err(1, "realloc"); 1270 error = getsockopt(s, IPPROTO_TCP, TCP_STATS, 1271 statsb, &sockoptlen); 1272 } 1273 if (error != 0) 1274 err(1, "getsockopt"); 1275 } 1276 1277 sb = sbuf_new_auto(); 1278 error = stats_blob_tostr(statsb, sb, SB_STRFMT_JSON, SB_TOSTR_META); 1279 if (error != 0) 1280 errc(1, error, "stats_blob_tostr"); 1281 1282 error = sbuf_finish(sb); 1283 if (error != 0) 1284 err(1, "sbuf_finish"); 1285 1286 fprintf(stderr, "%s\n", sbuf_data(sb)); 1287 #endif 1288 } 1289 1290 void 1291 set_common_sockopts(int s, int af) 1292 { 1293 int x = 1; 1294 1295 if (Sflag) { 1296 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG, 1297 &x, sizeof(x)) == -1) 1298 err(1, NULL); 1299 } 1300 if (Dflag) { 1301 if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 1302 &x, sizeof(x)) == -1) 1303 err(1, NULL); 1304 } 1305 if (Tflag != -1) { 1306 int proto, option; 1307 1308 if (af == AF_INET6) { 1309 proto = IPPROTO_IPV6; 1310 option = IPV6_TCLASS; 1311 } else { 1312 proto = IPPROTO_IP; 1313 option = IP_TOS; 1314 } 1315 1316 if (setsockopt(s, proto, option, &Tflag, sizeof(Tflag)) == -1) 1317 err(1, "set IP ToS"); 1318 } 1319 if (Iflag) { 1320 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, 1321 &Iflag, sizeof(Iflag)) == -1) 1322 err(1, "set TCP receive buffer size"); 1323 } 1324 if (Oflag) { 1325 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, 1326 &Oflag, sizeof(Oflag)) == -1) 1327 err(1, "set TCP send buffer size"); 1328 } 1329 if (FreeBSD_Oflag) { 1330 if (setsockopt(s, IPPROTO_TCP, TCP_NOOPT, 1331 &FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1) 1332 err(1, "disable TCP options"); 1333 } 1334 if (FreeBSD_Mflag) 1335 FreeBSD_stats_setup(s); 1336 #ifdef IPSEC 1337 if (ipsec_policy[0] != NULL) 1338 add_ipsec_policy(s, af, ipsec_policy[0]); 1339 if (ipsec_policy[1] != NULL) 1340 add_ipsec_policy(s, af, ipsec_policy[1]); 1341 #endif 1342 } 1343 1344 int 1345 map_tos(char *s, int *val) 1346 { 1347 /* DiffServ Codepoints and other TOS mappings */ 1348 const struct toskeywords { 1349 const char *keyword; 1350 int val; 1351 } *t, toskeywords[] = { 1352 { "af11", IPTOS_DSCP_AF11 }, 1353 { "af12", IPTOS_DSCP_AF12 }, 1354 { "af13", IPTOS_DSCP_AF13 }, 1355 { "af21", IPTOS_DSCP_AF21 }, 1356 { "af22", IPTOS_DSCP_AF22 }, 1357 { "af23", IPTOS_DSCP_AF23 }, 1358 { "af31", IPTOS_DSCP_AF31 }, 1359 { "af32", IPTOS_DSCP_AF32 }, 1360 { "af33", IPTOS_DSCP_AF33 }, 1361 { "af41", IPTOS_DSCP_AF41 }, 1362 { "af42", IPTOS_DSCP_AF42 }, 1363 { "af43", IPTOS_DSCP_AF43 }, 1364 { "critical", IPTOS_PREC_CRITIC_ECP }, 1365 { "cs0", IPTOS_DSCP_CS0 }, 1366 { "cs1", IPTOS_DSCP_CS1 }, 1367 { "cs2", IPTOS_DSCP_CS2 }, 1368 { "cs3", IPTOS_DSCP_CS3 }, 1369 { "cs4", IPTOS_DSCP_CS4 }, 1370 { "cs5", IPTOS_DSCP_CS5 }, 1371 { "cs6", IPTOS_DSCP_CS6 }, 1372 { "cs7", IPTOS_DSCP_CS7 }, 1373 { "ef", IPTOS_DSCP_EF }, 1374 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL }, 1375 { "lowdelay", IPTOS_LOWDELAY }, 1376 { "netcontrol", IPTOS_PREC_NETCONTROL }, 1377 { "reliability", IPTOS_RELIABILITY }, 1378 { "throughput", IPTOS_THROUGHPUT }, 1379 { NULL, -1 }, 1380 }; 1381 1382 for (t = toskeywords; t->keyword != NULL; t++) { 1383 if (strcmp(s, t->keyword) == 0) { 1384 *val = t->val; 1385 return (1); 1386 } 1387 } 1388 1389 return (0); 1390 } 1391 1392 void 1393 report_connect(const struct sockaddr *sa, socklen_t salen) 1394 { 1395 char remote_host[NI_MAXHOST]; 1396 char remote_port[NI_MAXSERV]; 1397 int herr; 1398 int flags = NI_NUMERICSERV; 1399 1400 if (nflag) 1401 flags |= NI_NUMERICHOST; 1402 1403 if ((herr = getnameinfo(sa, salen, 1404 remote_host, sizeof(remote_host), 1405 remote_port, sizeof(remote_port), 1406 flags)) != 0) { 1407 if (herr == EAI_SYSTEM) 1408 err(1, "getnameinfo"); 1409 else 1410 errx(1, "getnameinfo: %s", gai_strerror(herr)); 1411 } 1412 1413 fprintf(stderr, 1414 "Connection from %s %s " 1415 "received!\n", remote_host, remote_port); 1416 } 1417 1418 void 1419 help(void) 1420 { 1421 usage(0); 1422 fprintf(stderr, "\tCommand Summary:\n\ 1423 \t-4 Use IPv4\n\ 1424 \t-6 Use IPv6\n\ 1425 \t-D Enable the debug socket option\n\ 1426 \t-d Detach from stdin\n"); 1427 #ifdef IPSEC 1428 fprintf(stderr, "\ 1429 \t-E Use IPsec ESP\n\ 1430 \t-e policy Use specified IPsec policy\n"); 1431 #endif 1432 fprintf(stderr, "\ 1433 \t-F Pass socket fd\n\ 1434 \t-h This help text\n\ 1435 \t-I length TCP receive buffer length\n\ 1436 \t-i secs\t Delay interval for lines sent, ports scanned\n\ 1437 \t-k Keep inbound sockets open for multiple connects\n\ 1438 \t-l Listen mode, for inbound connects\n\ 1439 \t-N Shutdown the network socket after EOF on stdin\n\ 1440 \t-n Suppress name/port resolutions\n\ 1441 \t--no-tcpopt Disable TCP options\n\ 1442 \t--sctp\t SCTP mode\n\ 1443 \t-O length TCP send buffer length\n\ 1444 \t-P proxyuser\tUsername for proxy authentication\n\ 1445 \t-p port\t Specify local port for remote connects\n\ 1446 \t-r Randomize remote ports\n\ 1447 \t-S Enable the TCP MD5 signature option\n\ 1448 \t-s addr\t Local source address\n\ 1449 \t-T toskeyword\tSet IP Type of Service\n\ 1450 \t-t Answer TELNET negotiation\n\ 1451 \t-U Use UNIX domain socket\n\ 1452 \t-u UDP mode\n\ 1453 \t-V rtable Specify alternate routing table\n\ 1454 \t-v Verbose\n\ 1455 \t-w secs\t Timeout for connects and final net reads\n\ 1456 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\ 1457 \t-x addr[:port]\tSpecify proxy address and port\n\ 1458 \t-z Zero-I/O mode [used for scanning]\n\ 1459 Port numbers can be individual or ranges: lo-hi [inclusive]\n"); 1460 #ifdef IPSEC 1461 fprintf(stderr, "\tSee ipsec_set_policy(3) for -e argument format\n"); 1462 #endif 1463 exit(1); 1464 } 1465 1466 #ifdef IPSEC 1467 void 1468 add_ipsec_policy(int s, int af, char *policy) 1469 { 1470 char *raw; 1471 int e; 1472 1473 raw = ipsec_set_policy(policy, strlen(policy)); 1474 if (raw == NULL) 1475 errx(1, "ipsec_set_policy `%s': %s", policy, 1476 ipsec_strerror()); 1477 if (af == AF_INET) 1478 e = setsockopt(s, IPPROTO_IP, IP_IPSEC_POLICY, raw, 1479 ipsec_get_policylen(raw)); 1480 if (af == AF_INET6) 1481 e = setsockopt(s, IPPROTO_IPV6, IPV6_IPSEC_POLICY, raw, 1482 ipsec_get_policylen(raw)); 1483 if (e < 0) 1484 err(1, "ipsec policy cannot be configured"); 1485 free(raw); 1486 if (vflag) 1487 fprintf(stderr, "ipsec policy configured: `%s'\n", policy); 1488 return; 1489 } 1490 #endif /* IPSEC */ 1491 1492 void 1493 usage(int ret) 1494 { 1495 fprintf(stderr, 1496 #ifdef IPSEC 1497 "usage: nc [-46DdEFhklNnrStUuvz] [-e policy] [-I length] [-i interval] [-O length]\n" 1498 #else 1499 "usage: nc [-46DdFhklNnrStUuvz] [-I length] [-i interval] [-O length]\n" 1500 #endif 1501 "\t [--no-tcpopt] [--sctp]\n" 1502 "\t [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n" 1503 "\t [-V rtable] [-w timeout] [-X proxy_protocol]\n" 1504 "\t [-x proxy_address[:port]] [destination] [port]\n"); 1505 if (ret) 1506 exit(1); 1507 } 1508