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 int tun_fd = -1; 116 char *portlist[PORT_MAX+1]; 117 char *unix_dg_tmp_socket; 118 119 void atelnet(int, unsigned char *, unsigned int); 120 void build_ports(char *); 121 void help(void); 122 int local_listen(char *, char *, struct addrinfo); 123 void readwrite(int); 124 void fdpass(int nfd) __attribute__((noreturn)); 125 int remote_connect(const char *, const char *, struct addrinfo); 126 int timeout_connect(int, const struct sockaddr *, socklen_t); 127 int socks_connect(const char *, const char *, struct addrinfo, 128 const char *, const char *, struct addrinfo, int, const char *); 129 int udptest(int); 130 int unix_bind(char *); 131 int unix_connect(char *); 132 int unix_listen(char *); 133 void FreeBSD_stats_setup(int); 134 void FreeBSD_stats_print(int); 135 void set_common_sockopts(int, int); 136 int map_tos(char *, int *); 137 void report_connect(const struct sockaddr *, socklen_t); 138 void usage(int); 139 ssize_t drainbuf(int, unsigned char *, size_t *); 140 ssize_t fillbuf(int, unsigned char *, size_t *); 141 142 #ifdef IPSEC 143 void add_ipsec_policy(int, int, char *); 144 145 char *ipsec_policy[2]; 146 #endif 147 148 enum { 149 FREEBSD_TUN = CHAR_MAX, /* avoid collision with return values from getopt */ 150 }; 151 152 int 153 main(int argc, char *argv[]) 154 { 155 int ch, s, ret, socksv, ipsec_count; 156 int numfibs; 157 size_t intsize = sizeof(int); 158 char *host, *uport; 159 struct addrinfo hints; 160 struct servent *sv; 161 socklen_t len; 162 struct sockaddr_storage cliaddr; 163 char *proxy; 164 const char *errstr, *proxyhost = "", *proxyport = NULL, *tundev = NULL; 165 struct addrinfo proxyhints; 166 char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE]; 167 struct option longopts[] = { 168 { "no-tcpopt", no_argument, &FreeBSD_Oflag, 1 }, 169 { "sctp", no_argument, &FreeBSD_sctp, 1 }, 170 { "tun", required_argument, NULL, FREEBSD_TUN }, 171 { NULL, 0, NULL, 0 } 172 }; 173 174 ret = 1; 175 ipsec_count = 0; 176 s = 0; 177 socksv = 5; 178 host = NULL; 179 uport = NULL; 180 sv = NULL; 181 182 signal(SIGPIPE, SIG_IGN); 183 184 while ((ch = getopt_long(argc, argv, 185 "46DdEe:FhI:i:klMNnoO:P:p:rSs:tT:UuV:vw:X:x:z", 186 longopts, NULL)) != -1) { 187 switch (ch) { 188 case '4': 189 family = AF_INET; 190 break; 191 case '6': 192 family = AF_INET6; 193 break; 194 case 'U': 195 family = AF_UNIX; 196 break; 197 case 'X': 198 if (strcasecmp(optarg, "connect") == 0) 199 socksv = -1; /* HTTP proxy CONNECT */ 200 else if (strcmp(optarg, "4") == 0) 201 socksv = 4; /* SOCKS v.4 */ 202 else if (strcmp(optarg, "5") == 0) 203 socksv = 5; /* SOCKS v.5 */ 204 else 205 errx(1, "unsupported proxy protocol"); 206 break; 207 case 'd': 208 dflag = 1; 209 break; 210 case 'e': 211 #ifdef IPSEC 212 ipsec_policy[ipsec_count++ % 2] = optarg; 213 #else 214 errx(1, "IPsec support unavailable."); 215 #endif 216 break; 217 case 'E': 218 #ifdef IPSEC 219 ipsec_policy[0] = "in ipsec esp/transport//require"; 220 ipsec_policy[1] = "out ipsec esp/transport//require"; 221 #else 222 errx(1, "IPsec support unavailable."); 223 #endif 224 break; 225 case 'F': 226 Fflag = 1; 227 break; 228 case 'h': 229 help(); 230 break; 231 case 'i': 232 iflag = strtonum(optarg, 0, UINT_MAX, &errstr); 233 if (errstr) 234 errx(1, "interval %s: %s", errstr, optarg); 235 break; 236 case 'k': 237 kflag = 1; 238 break; 239 case 'l': 240 lflag = 1; 241 break; 242 case 'M': 243 #ifndef WITH_STATS 244 errx(1, "-M requires stats(3) support"); 245 #else 246 FreeBSD_Mflag = 1; 247 #endif 248 break; 249 case 'N': 250 Nflag = 1; 251 break; 252 case 'n': 253 nflag = 1; 254 break; 255 case 'o': 256 fprintf(stderr, "option -o is deprecated.\n"); 257 break; 258 case 'P': 259 Pflag = optarg; 260 break; 261 case 'p': 262 pflag = optarg; 263 break; 264 case 'r': 265 rflag = 1; 266 break; 267 case 's': 268 sflag = optarg; 269 break; 270 case 't': 271 tflag = 1; 272 break; 273 case 'u': 274 uflag = 1; 275 break; 276 case 'V': 277 if (sysctlbyname("net.fibs", &numfibs, &intsize, NULL, 0) == -1) 278 errx(1, "Multiple FIBS not supported"); 279 rtableid = (int)strtonum(optarg, 0, 280 numfibs - 1, &errstr); 281 if (errstr) 282 errx(1, "rtable %s: %s", errstr, optarg); 283 break; 284 case 'v': 285 vflag = 1; 286 break; 287 case 'w': 288 timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr); 289 if (errstr) 290 errx(1, "timeout %s: %s", errstr, optarg); 291 timeout *= 1000; 292 break; 293 case 'x': 294 xflag = 1; 295 if ((proxy = strdup(optarg)) == NULL) 296 err(1, NULL); 297 break; 298 case 'z': 299 zflag = 1; 300 break; 301 case 'D': 302 Dflag = 1; 303 break; 304 case 'I': 305 Iflag = strtonum(optarg, 1, 65536 << 14, &errstr); 306 if (errstr != NULL) 307 errx(1, "TCP receive window %s: %s", 308 errstr, optarg); 309 break; 310 case 'O': 311 Oflag = strtonum(optarg, 1, 65536 << 14, &errstr); 312 if (errstr != NULL) { 313 if (strcmp(errstr, "invalid") != 0) 314 errx(1, "TCP send window %s: %s", 315 errstr, optarg); 316 } 317 break; 318 case 'S': 319 Sflag = 1; 320 break; 321 case 'T': 322 errstr = NULL; 323 errno = 0; 324 if (map_tos(optarg, &Tflag)) 325 break; 326 if (strlen(optarg) > 1 && optarg[0] == '0' && 327 optarg[1] == 'x') 328 Tflag = (int)strtol(optarg, NULL, 16); 329 else 330 Tflag = (int)strtonum(optarg, 0, 255, 331 &errstr); 332 if (Tflag < 0 || Tflag > 255 || errstr || errno) 333 errx(1, "illegal tos value %s", optarg); 334 break; 335 case FREEBSD_TUN: 336 tundev = optarg; 337 break; 338 case 0: 339 /* Long option. */ 340 break; 341 default: 342 usage(1); 343 } 344 } 345 argc -= optind; 346 argv += optind; 347 348 /* Cruft to make sure options are clean, and used properly. */ 349 if (argv[0] && !argv[1] && family == AF_UNIX) { 350 host = argv[0]; 351 uport = NULL; 352 } else if (argv[0] && !argv[1]) { 353 if (!lflag) 354 usage(1); 355 uport = argv[0]; 356 host = NULL; 357 } else if (argv[0] && argv[1]) { 358 host = argv[0]; 359 uport = argv[1]; 360 } else 361 usage(1); 362 363 if (lflag && sflag) 364 errx(1, "cannot use -s and -l"); 365 if (lflag && pflag) 366 errx(1, "cannot use -p and -l"); 367 if (lflag && zflag) 368 errx(1, "cannot use -z and -l"); 369 if (!lflag && kflag) 370 errx(1, "must use -l with -k"); 371 if (FreeBSD_sctp) { 372 if (uflag) 373 errx(1, "cannot use -u and --sctp"); 374 if (family == AF_UNIX) 375 errx(1, "cannot use -U and --sctp"); 376 } 377 if (tundev != NULL) { 378 if (!uflag) 379 errx(1, "must use --tun with -u"); 380 tun_fd = open(tundev, O_RDWR); 381 if (tun_fd == -1) 382 errx(1, "unable to open tun device %s", tundev); 383 } 384 385 /* Get name of temporary socket for unix datagram client */ 386 if ((family == AF_UNIX) && uflag && !lflag) { 387 if (sflag) { 388 unix_dg_tmp_socket = sflag; 389 } else { 390 strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX", 391 UNIX_DG_TMP_SOCKET_SIZE); 392 if (mktemp(unix_dg_tmp_socket_buf) == NULL) 393 err(1, "mktemp"); 394 unix_dg_tmp_socket = unix_dg_tmp_socket_buf; 395 } 396 } 397 398 /* Initialize addrinfo structure. */ 399 if (family != AF_UNIX) { 400 memset(&hints, 0, sizeof(struct addrinfo)); 401 hints.ai_family = family; 402 hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 403 hints.ai_protocol = uflag ? IPPROTO_UDP : 404 FreeBSD_sctp ? IPPROTO_SCTP : IPPROTO_TCP; 405 if (nflag) 406 hints.ai_flags |= AI_NUMERICHOST; 407 } 408 409 if (xflag) { 410 if (uflag) 411 errx(1, "no proxy support for UDP mode"); 412 413 if (FreeBSD_sctp) 414 errx(1, "no proxy support for SCTP mode"); 415 416 if (lflag) 417 errx(1, "no proxy support for listen"); 418 419 if (family == AF_UNIX) 420 errx(1, "no proxy support for unix sockets"); 421 422 /* XXX IPv6 transport to proxy would probably work */ 423 if (family == AF_INET6) 424 errx(1, "no proxy support for IPv6"); 425 426 if (sflag) 427 errx(1, "no proxy support for local source address"); 428 429 proxyhost = strsep(&proxy, ":"); 430 proxyport = proxy; 431 432 memset(&proxyhints, 0, sizeof(struct addrinfo)); 433 proxyhints.ai_family = family; 434 proxyhints.ai_socktype = SOCK_STREAM; 435 proxyhints.ai_protocol = IPPROTO_TCP; 436 if (nflag) 437 proxyhints.ai_flags |= AI_NUMERICHOST; 438 } 439 440 if (lflag) { 441 int connfd; 442 ret = 0; 443 444 if (family == AF_UNIX) { 445 if (uflag) 446 s = unix_bind(host); 447 else 448 s = unix_listen(host); 449 } 450 451 /* Allow only one connection at a time, but stay alive. */ 452 for (;;) { 453 if (family != AF_UNIX) 454 s = local_listen(host, uport, hints); 455 if (s < 0) 456 err(1, NULL); 457 /* 458 * For UDP and -k, don't connect the socket, let it 459 * receive datagrams from multiple socket pairs. 460 */ 461 if (uflag && kflag) 462 readwrite(s); 463 /* 464 * For UDP and not -k, we will use recvfrom() initially 465 * to wait for a caller, then use the regular functions 466 * to talk to the caller. 467 */ 468 else if (uflag && !kflag) { 469 int rv, plen; 470 char buf[16384]; 471 struct sockaddr_storage z; 472 473 len = sizeof(z); 474 plen = 2048; 475 rv = recvfrom(s, buf, plen, MSG_PEEK, 476 (struct sockaddr *)&z, &len); 477 if (rv < 0) 478 err(1, "recvfrom"); 479 480 rv = connect(s, (struct sockaddr *)&z, len); 481 if (rv < 0) 482 err(1, "connect"); 483 484 if (vflag) 485 report_connect((struct sockaddr *)&z, len); 486 487 readwrite(s); 488 } else { 489 len = sizeof(cliaddr); 490 connfd = accept(s, (struct sockaddr *)&cliaddr, 491 &len); 492 if (connfd == -1) { 493 /* For now, all errnos are fatal */ 494 err(1, "accept"); 495 } 496 if (vflag) 497 report_connect((struct sockaddr *)&cliaddr, len); 498 499 if (FreeBSD_Mflag) 500 FreeBSD_stats_setup(connfd); 501 readwrite(connfd); 502 close(connfd); 503 } 504 505 if (family != AF_UNIX) 506 close(s); 507 else if (uflag) { 508 if (connect(s, NULL, 0) < 0) 509 err(1, "connect"); 510 } 511 512 if (!kflag) 513 break; 514 } 515 } else if (family == AF_UNIX) { 516 ret = 0; 517 518 if ((s = unix_connect(host)) > 0 && !zflag) { 519 readwrite(s); 520 close(s); 521 } else 522 ret = 1; 523 524 if (uflag) 525 unlink(unix_dg_tmp_socket); 526 exit(ret); 527 528 } else { 529 int i = 0; 530 531 /* Construct the portlist[] array. */ 532 build_ports(uport); 533 534 /* Cycle through portlist, connecting to each port. */ 535 for (i = 0; portlist[i] != NULL; i++) { 536 if (s) 537 close(s); 538 539 if (xflag) 540 s = socks_connect(host, portlist[i], hints, 541 proxyhost, proxyport, proxyhints, socksv, 542 Pflag); 543 else 544 s = remote_connect(host, portlist[i], hints); 545 546 if (s < 0) 547 continue; 548 549 ret = 0; 550 if (vflag || zflag) { 551 /* For UDP, make sure we are connected. */ 552 if (uflag) { 553 if (udptest(s) == -1) { 554 ret = 1; 555 continue; 556 } 557 } 558 559 /* Don't look up port if -n. */ 560 if (nflag) 561 sv = NULL; 562 else { 563 sv = getservbyport( 564 ntohs(atoi(portlist[i])), 565 uflag ? "udp" : "tcp"); 566 } 567 568 fprintf(stderr, 569 "Connection to %s %s port [%s/%s] " 570 "succeeded!\n", host, portlist[i], 571 uflag ? "udp" : "tcp", 572 sv ? sv->s_name : "*"); 573 } 574 if (Fflag) 575 fdpass(s); 576 else if (!zflag) 577 readwrite(s); 578 } 579 } 580 581 if (s) 582 close(s); 583 if (tun_fd != -1) 584 close(tun_fd); 585 586 exit(ret); 587 } 588 589 /* 590 * unix_bind() 591 * Returns a unix socket bound to the given path 592 */ 593 int 594 unix_bind(char *path) 595 { 596 struct sockaddr_un sun; 597 int s; 598 599 /* Create unix domain socket. */ 600 if ((s = socket(AF_UNIX, uflag ? SOCK_DGRAM : SOCK_STREAM, 601 0)) < 0) 602 return (-1); 603 604 memset(&sun, 0, sizeof(struct sockaddr_un)); 605 sun.sun_family = AF_UNIX; 606 607 if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >= 608 sizeof(sun.sun_path)) { 609 close(s); 610 errno = ENAMETOOLONG; 611 return (-1); 612 } 613 614 if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) { 615 close(s); 616 return (-1); 617 } 618 return (s); 619 } 620 621 /* 622 * unix_connect() 623 * Returns a socket connected to a local unix socket. Returns -1 on failure. 624 */ 625 int 626 unix_connect(char *path) 627 { 628 struct sockaddr_un sun; 629 int s; 630 631 if (uflag) { 632 if ((s = unix_bind(unix_dg_tmp_socket)) < 0) 633 return (-1); 634 } else { 635 if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) 636 return (-1); 637 } 638 (void)fcntl(s, F_SETFD, FD_CLOEXEC); 639 640 memset(&sun, 0, sizeof(struct sockaddr_un)); 641 sun.sun_family = AF_UNIX; 642 643 if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >= 644 sizeof(sun.sun_path)) { 645 close(s); 646 errno = ENAMETOOLONG; 647 return (-1); 648 } 649 if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) { 650 close(s); 651 return (-1); 652 } 653 return (s); 654 655 } 656 657 /* 658 * unix_listen() 659 * Create a unix domain socket, and listen on it. 660 */ 661 int 662 unix_listen(char *path) 663 { 664 int s; 665 if ((s = unix_bind(path)) < 0) 666 return (-1); 667 668 if (listen(s, 5) < 0) { 669 close(s); 670 return (-1); 671 } 672 return (s); 673 } 674 675 /* 676 * remote_connect() 677 * Returns a socket connected to a remote host. Properly binds to a local 678 * port or source address if needed. Returns -1 on failure. 679 */ 680 int 681 remote_connect(const char *host, const char *port, struct addrinfo hints) 682 { 683 struct addrinfo *res, *res0; 684 int s, error, on = 1; 685 686 if ((error = getaddrinfo(host, port, &hints, &res))) 687 errx(1, "getaddrinfo: %s", gai_strerror(error)); 688 689 res0 = res; 690 do { 691 if ((s = socket(res0->ai_family, res0->ai_socktype, 692 res0->ai_protocol)) < 0) 693 continue; 694 695 if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_SETFIB, 696 &rtableid, sizeof(rtableid)) == -1)) 697 err(1, "setsockopt SO_SETFIB"); 698 699 /* Bind to a local port or source address if specified. */ 700 if (sflag || pflag) { 701 struct addrinfo ahints, *ares; 702 703 /* try IP_BINDANY, but don't insist */ 704 setsockopt(s, IPPROTO_IP, IP_BINDANY, &on, sizeof(on)); 705 memset(&ahints, 0, sizeof(struct addrinfo)); 706 ahints.ai_family = res0->ai_family; 707 ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM; 708 ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP; 709 ahints.ai_flags = AI_PASSIVE; 710 if ((error = getaddrinfo(sflag, pflag, &ahints, &ares))) 711 errx(1, "getaddrinfo: %s", gai_strerror(error)); 712 713 if (bind(s, (struct sockaddr *)ares->ai_addr, 714 ares->ai_addrlen) < 0) 715 err(1, "bind failed"); 716 freeaddrinfo(ares); 717 } 718 719 set_common_sockopts(s, res0->ai_family); 720 721 if (timeout_connect(s, res0->ai_addr, res0->ai_addrlen) == 0) 722 break; 723 else if (vflag) 724 warn("connect to %s port %s (%s) failed", host, port, 725 uflag ? "udp" : "tcp"); 726 727 close(s); 728 s = -1; 729 } while ((res0 = res0->ai_next) != NULL); 730 731 freeaddrinfo(res); 732 733 return (s); 734 } 735 736 int 737 timeout_connect(int s, const struct sockaddr *name, socklen_t namelen) 738 { 739 struct pollfd pfd; 740 socklen_t optlen; 741 int flags, optval; 742 int ret; 743 744 if (timeout != -1) { 745 flags = fcntl(s, F_GETFL, 0); 746 if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1) 747 err(1, "set non-blocking mode"); 748 } 749 750 if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) { 751 pfd.fd = s; 752 pfd.events = POLLOUT; 753 if ((ret = poll(&pfd, 1, timeout)) == 1) { 754 optlen = sizeof(optval); 755 if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR, 756 &optval, &optlen)) == 0) { 757 errno = optval; 758 ret = optval == 0 ? 0 : -1; 759 } 760 } else if (ret == 0) { 761 errno = ETIMEDOUT; 762 ret = -1; 763 } else 764 err(1, "poll failed"); 765 } 766 767 if (timeout != -1 && fcntl(s, F_SETFL, flags) == -1) 768 err(1, "restoring flags"); 769 770 return (ret); 771 } 772 773 /* 774 * local_listen() 775 * Returns a socket listening on a local port, binds to specified source 776 * address. Returns -1 on failure. 777 */ 778 int 779 local_listen(char *host, char *port, struct addrinfo hints) 780 { 781 struct addrinfo *res, *res0; 782 int s, ret, x = 1; 783 int error; 784 785 /* Allow nodename to be null. */ 786 hints.ai_flags |= AI_PASSIVE; 787 788 /* 789 * In the case of binding to a wildcard address 790 * default to binding to an ipv4 address. 791 */ 792 if (host == NULL && hints.ai_family == AF_UNSPEC) 793 hints.ai_family = AF_INET; 794 795 if ((error = getaddrinfo(host, port, &hints, &res))) 796 errx(1, "getaddrinfo: %s", gai_strerror(error)); 797 798 res0 = res; 799 do { 800 if ((s = socket(res0->ai_family, res0->ai_socktype, 801 res0->ai_protocol)) < 0) 802 continue; 803 804 if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_SETFIB, 805 &rtableid, sizeof(rtableid)) == -1)) 806 err(1, "setsockopt SO_SETFIB"); 807 808 ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x)); 809 if (ret == -1) 810 err(1, NULL); 811 812 if (FreeBSD_Oflag) { 813 if (setsockopt(s, IPPROTO_TCP, TCP_NOOPT, 814 &FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1) 815 err(1, "disable TCP options"); 816 } 817 818 set_common_sockopts(s, res0->ai_family); 819 820 if (bind(s, (struct sockaddr *)res0->ai_addr, 821 res0->ai_addrlen) == 0) 822 break; 823 824 close(s); 825 s = -1; 826 } while ((res0 = res0->ai_next) != NULL); 827 828 if (!uflag && s != -1) { 829 if (listen(s, 1) < 0) 830 err(1, "listen"); 831 } 832 833 freeaddrinfo(res); 834 835 return (s); 836 } 837 838 /* 839 * readwrite() 840 * Loop that polls on the network file descriptor and stdin. 841 */ 842 void 843 readwrite(int net_fd) 844 { 845 struct pollfd pfd[4]; 846 int stdin_fd = STDIN_FILENO; 847 int stdout_fd = STDOUT_FILENO; 848 unsigned char netinbuf[BUFSIZE]; 849 size_t netinbufpos = 0; 850 unsigned char stdinbuf[BUFSIZE]; 851 size_t stdinbufpos = 0; 852 int n, num_fds; 853 int stats_printed = 0; 854 ssize_t ret; 855 856 /* don't read from stdin if requested */ 857 if (dflag) 858 stdin_fd = -1; 859 860 /* stdin */ 861 pfd[POLL_STDIN].fd = (tun_fd != -1) ? tun_fd : stdin_fd; 862 pfd[POLL_STDIN].events = POLLIN; 863 864 /* network out */ 865 pfd[POLL_NETOUT].fd = net_fd; 866 pfd[POLL_NETOUT].events = 0; 867 868 /* network in */ 869 pfd[POLL_NETIN].fd = net_fd; 870 pfd[POLL_NETIN].events = POLLIN; 871 872 /* stdout */ 873 pfd[POLL_STDOUT].fd = (tun_fd != -1) ? tun_fd : stdout_fd; 874 pfd[POLL_STDOUT].events = 0; 875 876 while (1) { 877 /* both inputs are gone, buffers are empty, we are done */ 878 if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1 879 && stdinbufpos == 0 && netinbufpos == 0) { 880 if (FreeBSD_Mflag && !stats_printed) 881 FreeBSD_stats_print(net_fd); 882 close(net_fd); 883 return; 884 } 885 /* both outputs are gone, we can't continue */ 886 if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) { 887 if (FreeBSD_Mflag && !stats_printed) 888 FreeBSD_stats_print(net_fd); 889 close(net_fd); 890 return; 891 } 892 /* listen and net in gone, queues empty, done */ 893 if (lflag && pfd[POLL_NETIN].fd == -1 894 && stdinbufpos == 0 && netinbufpos == 0) { 895 if (FreeBSD_Mflag && !stats_printed) 896 FreeBSD_stats_print(net_fd); 897 close(net_fd); 898 return; 899 } 900 901 /* help says -i is for "wait between lines sent". We read and 902 * write arbitrary amounts of data, and we don't want to start 903 * scanning for newlines, so this is as good as it gets */ 904 if (iflag) 905 sleep(iflag); 906 907 /* poll */ 908 num_fds = poll(pfd, 4, timeout); 909 910 /* treat poll errors */ 911 if (num_fds == -1) { 912 close(net_fd); 913 err(1, "polling error"); 914 } 915 916 /* timeout happened */ 917 if (num_fds == 0) { 918 if (FreeBSD_Mflag) 919 FreeBSD_stats_print(net_fd); 920 return; 921 } 922 923 /* treat socket error conditions */ 924 for (n = 0; n < 4; n++) { 925 if (pfd[n].revents & (POLLERR|POLLNVAL)) { 926 pfd[n].fd = -1; 927 } 928 } 929 /* reading is possible after HUP */ 930 if (pfd[POLL_STDIN].events & POLLIN && 931 pfd[POLL_STDIN].revents & POLLHUP && 932 ! (pfd[POLL_STDIN].revents & POLLIN)) 933 pfd[POLL_STDIN].fd = -1; 934 935 if (pfd[POLL_NETIN].events & POLLIN && 936 pfd[POLL_NETIN].revents & POLLHUP && 937 ! (pfd[POLL_NETIN].revents & POLLIN)) 938 pfd[POLL_NETIN].fd = -1; 939 940 if (pfd[POLL_NETOUT].revents & POLLHUP) { 941 if (Nflag) 942 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 943 pfd[POLL_NETOUT].fd = -1; 944 } 945 /* if HUP, stop watching stdout */ 946 if (pfd[POLL_STDOUT].revents & POLLHUP) 947 pfd[POLL_STDOUT].fd = -1; 948 /* if no net out, stop watching stdin */ 949 if (pfd[POLL_NETOUT].fd == -1) 950 pfd[POLL_STDIN].fd = -1; 951 /* if no stdout, stop watching net in */ 952 if (pfd[POLL_STDOUT].fd == -1) { 953 if (pfd[POLL_NETIN].fd != -1) 954 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 955 pfd[POLL_NETIN].fd = -1; 956 } 957 958 /* try to read from stdin */ 959 if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) { 960 ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf, 961 &stdinbufpos); 962 /* error or eof on stdin - remove from pfd */ 963 if (ret == 0 || ret == -1) 964 pfd[POLL_STDIN].fd = -1; 965 /* read something - poll net out */ 966 if (stdinbufpos > 0) 967 pfd[POLL_NETOUT].events = POLLOUT; 968 /* filled buffer - remove self from polling */ 969 if (stdinbufpos == BUFSIZE) 970 pfd[POLL_STDIN].events = 0; 971 } 972 /* try to write to network */ 973 if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) { 974 ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf, 975 &stdinbufpos); 976 if (ret == -1) 977 pfd[POLL_NETOUT].fd = -1; 978 /* buffer empty - remove self from polling */ 979 if (stdinbufpos == 0) 980 pfd[POLL_NETOUT].events = 0; 981 /* buffer no longer full - poll stdin again */ 982 if (stdinbufpos < BUFSIZE) 983 pfd[POLL_STDIN].events = POLLIN; 984 } 985 /* try to read from network */ 986 if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) { 987 ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf, 988 &netinbufpos); 989 if (ret == -1) 990 pfd[POLL_NETIN].fd = -1; 991 /* eof on net in - remove from pfd */ 992 if (ret == 0) { 993 shutdown(pfd[POLL_NETIN].fd, SHUT_RD); 994 pfd[POLL_NETIN].fd = -1; 995 } 996 /* read something - poll stdout */ 997 if (netinbufpos > 0) 998 pfd[POLL_STDOUT].events = POLLOUT; 999 /* filled buffer - remove self from polling */ 1000 if (netinbufpos == BUFSIZE) 1001 pfd[POLL_NETIN].events = 0; 1002 /* handle telnet */ 1003 if (tflag) 1004 atelnet(pfd[POLL_NETIN].fd, netinbuf, 1005 netinbufpos); 1006 } 1007 /* try to write to stdout */ 1008 if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) { 1009 ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf, 1010 &netinbufpos); 1011 if (ret == -1) 1012 pfd[POLL_STDOUT].fd = -1; 1013 /* buffer empty - remove self from polling */ 1014 if (netinbufpos == 0) 1015 pfd[POLL_STDOUT].events = 0; 1016 /* buffer no longer full - poll net in again */ 1017 if (netinbufpos < BUFSIZE) 1018 pfd[POLL_NETIN].events = POLLIN; 1019 } 1020 1021 /* stdin gone and queue empty? */ 1022 if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) { 1023 if (pfd[POLL_NETOUT].fd != -1 && Nflag) { 1024 if (FreeBSD_Mflag) { 1025 FreeBSD_stats_print(net_fd); 1026 stats_printed = 1; 1027 } 1028 shutdown(pfd[POLL_NETOUT].fd, SHUT_WR); 1029 } 1030 pfd[POLL_NETOUT].fd = -1; 1031 } 1032 /* net in gone and queue empty? */ 1033 if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) { 1034 pfd[POLL_STDOUT].fd = -1; 1035 } 1036 } 1037 } 1038 1039 ssize_t 1040 drainbuf(int fd, unsigned char *buf, size_t *bufpos) 1041 { 1042 ssize_t n; 1043 ssize_t adjust; 1044 1045 n = write(fd, buf, *bufpos); 1046 /* don't treat EAGAIN, EINTR as error */ 1047 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1048 n = -2; 1049 if (n <= 0) 1050 return n; 1051 /* adjust buffer */ 1052 adjust = *bufpos - n; 1053 if (adjust > 0) 1054 memmove(buf, buf + n, adjust); 1055 *bufpos -= n; 1056 return n; 1057 } 1058 1059 1060 ssize_t 1061 fillbuf(int fd, unsigned char *buf, size_t *bufpos) 1062 { 1063 size_t num = BUFSIZE - *bufpos; 1064 ssize_t n; 1065 1066 n = read(fd, buf + *bufpos, num); 1067 /* don't treat EAGAIN, EINTR as error */ 1068 if (n == -1 && (errno == EAGAIN || errno == EINTR)) 1069 n = -2; 1070 if (n <= 0) 1071 return n; 1072 *bufpos += n; 1073 return n; 1074 } 1075 1076 /* 1077 * fdpass() 1078 * Pass the connected file descriptor to stdout and exit. 1079 */ 1080 void 1081 fdpass(int nfd) 1082 { 1083 struct msghdr mh; 1084 union { 1085 struct cmsghdr hdr; 1086 char buf[CMSG_SPACE(sizeof(int))]; 1087 } cmsgbuf; 1088 struct cmsghdr *cmsg; 1089 struct iovec iov; 1090 char c = '\0'; 1091 ssize_t r; 1092 struct pollfd pfd; 1093 1094 /* Avoid obvious stupidity */ 1095 if (isatty(STDOUT_FILENO)) 1096 errx(1, "Cannot pass file descriptor to tty"); 1097 1098 bzero(&mh, sizeof(mh)); 1099 bzero(&cmsgbuf, sizeof(cmsgbuf)); 1100 bzero(&iov, sizeof(iov)); 1101 1102 mh.msg_control = (caddr_t)&cmsgbuf.buf; 1103 mh.msg_controllen = sizeof(cmsgbuf.buf); 1104 cmsg = CMSG_FIRSTHDR(&mh); 1105 cmsg->cmsg_len = CMSG_LEN(sizeof(int)); 1106 cmsg->cmsg_level = SOL_SOCKET; 1107 cmsg->cmsg_type = SCM_RIGHTS; 1108 *(int *)CMSG_DATA(cmsg) = nfd; 1109 1110 iov.iov_base = &c; 1111 iov.iov_len = 1; 1112 mh.msg_iov = &iov; 1113 mh.msg_iovlen = 1; 1114 1115 bzero(&pfd, sizeof(pfd)); 1116 pfd.fd = STDOUT_FILENO; 1117 pfd.events = POLLOUT; 1118 for (;;) { 1119 r = sendmsg(STDOUT_FILENO, &mh, 0); 1120 if (r == -1) { 1121 if (errno == EAGAIN || errno == EINTR) { 1122 if (poll(&pfd, 1, -1) == -1) 1123 err(1, "poll"); 1124 continue; 1125 } 1126 err(1, "sendmsg"); 1127 } else if (r != 1) 1128 errx(1, "sendmsg: unexpected return value %zd", r); 1129 else 1130 break; 1131 } 1132 exit(0); 1133 } 1134 1135 /* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */ 1136 void 1137 atelnet(int nfd, unsigned char *buf, unsigned int size) 1138 { 1139 unsigned char *p, *end; 1140 unsigned char obuf[4]; 1141 1142 if (size < 3) 1143 return; 1144 end = buf + size - 2; 1145 1146 for (p = buf; p < end; p++) { 1147 if (*p != IAC) 1148 continue; 1149 1150 obuf[0] = IAC; 1151 p++; 1152 if ((*p == WILL) || (*p == WONT)) 1153 obuf[1] = DONT; 1154 else if ((*p == DO) || (*p == DONT)) 1155 obuf[1] = WONT; 1156 else 1157 continue; 1158 1159 p++; 1160 obuf[2] = *p; 1161 if (atomicio(vwrite, nfd, obuf, 3) != 3) 1162 warn("Write Error!"); 1163 } 1164 } 1165 1166 /* 1167 * build_ports() 1168 * Build an array of ports in portlist[], listing each port 1169 * that we should try to connect to. 1170 */ 1171 void 1172 build_ports(char *p) 1173 { 1174 const char *errstr; 1175 char *n; 1176 int hi, lo, cp; 1177 int x = 0; 1178 1179 if ((n = strchr(p, '-')) != NULL) { 1180 *n = '\0'; 1181 n++; 1182 1183 /* Make sure the ports are in order: lowest->highest. */ 1184 hi = strtonum(n, 1, PORT_MAX, &errstr); 1185 if (errstr) 1186 errx(1, "port number %s: %s", errstr, n); 1187 lo = strtonum(p, 1, PORT_MAX, &errstr); 1188 if (errstr) 1189 errx(1, "port number %s: %s", errstr, p); 1190 1191 if (lo > hi) { 1192 cp = hi; 1193 hi = lo; 1194 lo = cp; 1195 } 1196 1197 /* Load ports sequentially. */ 1198 for (cp = lo; cp <= hi; cp++) { 1199 portlist[x] = calloc(1, PORT_MAX_LEN); 1200 if (portlist[x] == NULL) 1201 err(1, NULL); 1202 snprintf(portlist[x], PORT_MAX_LEN, "%d", cp); 1203 x++; 1204 } 1205 1206 /* Randomly swap ports. */ 1207 if (rflag) { 1208 int y; 1209 char *c; 1210 1211 for (x = 0; x <= (hi - lo); x++) { 1212 y = (arc4random() & 0xFFFF) % (hi - lo); 1213 c = portlist[x]; 1214 portlist[x] = portlist[y]; 1215 portlist[y] = c; 1216 } 1217 } 1218 } else { 1219 hi = strtonum(p, 1, PORT_MAX, &errstr); 1220 if (errstr) 1221 errx(1, "port number %s: %s", errstr, p); 1222 portlist[0] = strdup(p); 1223 if (portlist[0] == NULL) 1224 err(1, NULL); 1225 } 1226 } 1227 1228 /* 1229 * udptest() 1230 * Do a few writes to see if the UDP port is there. 1231 * Fails once PF state table is full. 1232 */ 1233 int 1234 udptest(int s) 1235 { 1236 int i, ret; 1237 1238 for (i = 0; i <= 3; i++) { 1239 if (write(s, "X", 1) == 1) 1240 ret = 1; 1241 else 1242 ret = -1; 1243 } 1244 return (ret); 1245 } 1246 1247 void 1248 FreeBSD_stats_setup(int s) 1249 { 1250 1251 if (setsockopt(s, IPPROTO_TCP, TCP_STATS, 1252 &FreeBSD_Mflag, sizeof(FreeBSD_Mflag)) == -1) { 1253 if (errno == EOPNOTSUPP) { 1254 warnx("getsockopt(TCP_STATS) failed; " 1255 "kernel built without \"options STATS\"?"); 1256 } 1257 err(1, "enable TCP_STATS gathering"); 1258 } 1259 } 1260 1261 void 1262 FreeBSD_stats_print(int s) 1263 { 1264 #ifdef WITH_STATS 1265 struct statsblob *statsb; 1266 struct sbuf *sb; 1267 socklen_t sockoptlen; 1268 int error; 1269 1270 /* 1271 * This usleep is a workaround for TCP_STATS reporting 1272 * incorrect values for TXPB. 1273 */ 1274 usleep(100000); 1275 1276 sockoptlen = 2048; 1277 statsb = malloc(sockoptlen); 1278 if (statsb == NULL) 1279 err(1, "malloc"); 1280 error = getsockopt(s, IPPROTO_TCP, TCP_STATS, statsb, &sockoptlen); 1281 if (error != 0) { 1282 if (errno == EOVERFLOW && statsb->cursz > sockoptlen) { 1283 /* Retry with a larger size. */ 1284 sockoptlen = statsb->cursz; 1285 statsb = realloc(statsb, sockoptlen); 1286 if (statsb == NULL) 1287 err(1, "realloc"); 1288 error = getsockopt(s, IPPROTO_TCP, TCP_STATS, 1289 statsb, &sockoptlen); 1290 } 1291 if (error != 0) 1292 err(1, "getsockopt"); 1293 } 1294 1295 sb = sbuf_new_auto(); 1296 error = stats_blob_tostr(statsb, sb, SB_STRFMT_JSON, SB_TOSTR_META); 1297 if (error != 0) 1298 errc(1, error, "stats_blob_tostr"); 1299 1300 error = sbuf_finish(sb); 1301 if (error != 0) 1302 err(1, "sbuf_finish"); 1303 1304 fprintf(stderr, "%s\n", sbuf_data(sb)); 1305 #endif 1306 } 1307 1308 void 1309 set_common_sockopts(int s, int af) 1310 { 1311 int x = 1; 1312 1313 if (Sflag) { 1314 if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG, 1315 &x, sizeof(x)) == -1) 1316 err(1, NULL); 1317 } 1318 if (Dflag) { 1319 if (setsockopt(s, SOL_SOCKET, SO_DEBUG, 1320 &x, sizeof(x)) == -1) 1321 err(1, NULL); 1322 } 1323 if (Tflag != -1) { 1324 int proto, option; 1325 1326 if (af == AF_INET6) { 1327 proto = IPPROTO_IPV6; 1328 option = IPV6_TCLASS; 1329 } else { 1330 proto = IPPROTO_IP; 1331 option = IP_TOS; 1332 } 1333 1334 if (setsockopt(s, proto, option, &Tflag, sizeof(Tflag)) == -1) 1335 err(1, "set IP ToS"); 1336 } 1337 if (Iflag) { 1338 if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, 1339 &Iflag, sizeof(Iflag)) == -1) 1340 err(1, "set TCP receive buffer size"); 1341 } 1342 if (Oflag) { 1343 if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, 1344 &Oflag, sizeof(Oflag)) == -1) 1345 err(1, "set TCP send buffer size"); 1346 } 1347 if (FreeBSD_Oflag) { 1348 if (setsockopt(s, IPPROTO_TCP, TCP_NOOPT, 1349 &FreeBSD_Oflag, sizeof(FreeBSD_Oflag)) == -1) 1350 err(1, "disable TCP options"); 1351 } 1352 if (FreeBSD_Mflag) 1353 FreeBSD_stats_setup(s); 1354 #ifdef IPSEC 1355 if (ipsec_policy[0] != NULL) 1356 add_ipsec_policy(s, af, ipsec_policy[0]); 1357 if (ipsec_policy[1] != NULL) 1358 add_ipsec_policy(s, af, ipsec_policy[1]); 1359 #endif 1360 } 1361 1362 int 1363 map_tos(char *s, int *val) 1364 { 1365 /* DiffServ Codepoints and other TOS mappings */ 1366 const struct toskeywords { 1367 const char *keyword; 1368 int val; 1369 } *t, toskeywords[] = { 1370 { "af11", IPTOS_DSCP_AF11 }, 1371 { "af12", IPTOS_DSCP_AF12 }, 1372 { "af13", IPTOS_DSCP_AF13 }, 1373 { "af21", IPTOS_DSCP_AF21 }, 1374 { "af22", IPTOS_DSCP_AF22 }, 1375 { "af23", IPTOS_DSCP_AF23 }, 1376 { "af31", IPTOS_DSCP_AF31 }, 1377 { "af32", IPTOS_DSCP_AF32 }, 1378 { "af33", IPTOS_DSCP_AF33 }, 1379 { "af41", IPTOS_DSCP_AF41 }, 1380 { "af42", IPTOS_DSCP_AF42 }, 1381 { "af43", IPTOS_DSCP_AF43 }, 1382 { "critical", IPTOS_PREC_CRITIC_ECP }, 1383 { "cs0", IPTOS_DSCP_CS0 }, 1384 { "cs1", IPTOS_DSCP_CS1 }, 1385 { "cs2", IPTOS_DSCP_CS2 }, 1386 { "cs3", IPTOS_DSCP_CS3 }, 1387 { "cs4", IPTOS_DSCP_CS4 }, 1388 { "cs5", IPTOS_DSCP_CS5 }, 1389 { "cs6", IPTOS_DSCP_CS6 }, 1390 { "cs7", IPTOS_DSCP_CS7 }, 1391 { "ef", IPTOS_DSCP_EF }, 1392 { "inetcontrol", IPTOS_PREC_INTERNETCONTROL }, 1393 { "lowdelay", IPTOS_LOWDELAY }, 1394 { "netcontrol", IPTOS_PREC_NETCONTROL }, 1395 { "reliability", IPTOS_RELIABILITY }, 1396 { "throughput", IPTOS_THROUGHPUT }, 1397 { NULL, -1 }, 1398 }; 1399 1400 for (t = toskeywords; t->keyword != NULL; t++) { 1401 if (strcmp(s, t->keyword) == 0) { 1402 *val = t->val; 1403 return (1); 1404 } 1405 } 1406 1407 return (0); 1408 } 1409 1410 void 1411 report_connect(const struct sockaddr *sa, socklen_t salen) 1412 { 1413 char remote_host[NI_MAXHOST]; 1414 char remote_port[NI_MAXSERV]; 1415 int herr; 1416 int flags = NI_NUMERICSERV; 1417 1418 if (nflag) 1419 flags |= NI_NUMERICHOST; 1420 1421 if ((herr = getnameinfo(sa, salen, 1422 remote_host, sizeof(remote_host), 1423 remote_port, sizeof(remote_port), 1424 flags)) != 0) { 1425 if (herr == EAI_SYSTEM) 1426 err(1, "getnameinfo"); 1427 else 1428 errx(1, "getnameinfo: %s", gai_strerror(herr)); 1429 } 1430 1431 fprintf(stderr, 1432 "Connection from %s %s " 1433 "received!\n", remote_host, remote_port); 1434 } 1435 1436 void 1437 help(void) 1438 { 1439 usage(0); 1440 fprintf(stderr, "\tCommand Summary:\n\ 1441 \t-4 Use IPv4\n\ 1442 \t-6 Use IPv6\n\ 1443 \t-D Enable the debug socket option\n\ 1444 \t-d Detach from stdin\n"); 1445 #ifdef IPSEC 1446 fprintf(stderr, "\ 1447 \t-E Use IPsec ESP\n\ 1448 \t-e policy Use specified IPsec policy\n"); 1449 #endif 1450 fprintf(stderr, "\ 1451 \t-F Pass socket fd\n\ 1452 \t-h This help text\n\ 1453 \t-I length TCP receive buffer length\n\ 1454 \t-i secs\t Delay interval for lines sent, ports scanned\n\ 1455 \t-k Keep inbound sockets open for multiple connects\n\ 1456 \t-l Listen mode, for inbound connects\n\ 1457 \t-N Shutdown the network socket after EOF on stdin\n\ 1458 \t-n Suppress name/port resolutions\n\ 1459 \t--no-tcpopt Disable TCP options\n\ 1460 \t--sctp\t SCTP mode\n\ 1461 \t--tun tundev Use tun device rather than stdio\n\ 1462 \t-O length TCP send buffer length\n\ 1463 \t-P proxyuser\tUsername for proxy authentication\n\ 1464 \t-p port\t Specify local port for remote connects\n\ 1465 \t-r Randomize remote ports\n\ 1466 \t-S Enable the TCP MD5 signature option\n\ 1467 \t-s addr\t Local source address\n\ 1468 \t-T toskeyword\tSet IP Type of Service\n\ 1469 \t-t Answer TELNET negotiation\n\ 1470 \t-U Use UNIX domain socket\n\ 1471 \t-u UDP mode\n\ 1472 \t-V rtable Specify alternate routing table\n\ 1473 \t-v Verbose\n\ 1474 \t-w secs\t Timeout for connects and final net reads\n\ 1475 \t-X proto Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\ 1476 \t-x addr[:port]\tSpecify proxy address and port\n\ 1477 \t-z Zero-I/O mode [used for scanning]\n\ 1478 Port numbers can be individual or ranges: lo-hi [inclusive]\n"); 1479 #ifdef IPSEC 1480 fprintf(stderr, "\tSee ipsec_set_policy(3) for -e argument format\n"); 1481 #endif 1482 exit(1); 1483 } 1484 1485 #ifdef IPSEC 1486 void 1487 add_ipsec_policy(int s, int af, char *policy) 1488 { 1489 char *raw; 1490 int e; 1491 1492 raw = ipsec_set_policy(policy, strlen(policy)); 1493 if (raw == NULL) 1494 errx(1, "ipsec_set_policy `%s': %s", policy, 1495 ipsec_strerror()); 1496 if (af == AF_INET) 1497 e = setsockopt(s, IPPROTO_IP, IP_IPSEC_POLICY, raw, 1498 ipsec_get_policylen(raw)); 1499 if (af == AF_INET6) 1500 e = setsockopt(s, IPPROTO_IPV6, IPV6_IPSEC_POLICY, raw, 1501 ipsec_get_policylen(raw)); 1502 if (e < 0) 1503 err(1, "ipsec policy cannot be configured"); 1504 free(raw); 1505 if (vflag) 1506 fprintf(stderr, "ipsec policy configured: `%s'\n", policy); 1507 return; 1508 } 1509 #endif /* IPSEC */ 1510 1511 void 1512 usage(int ret) 1513 { 1514 fprintf(stderr, 1515 #ifdef IPSEC 1516 "usage: nc [-46DdEFhklNnrStUuvz] [-e policy] [-I length] [-i interval] [-O length]\n" 1517 #else 1518 "usage: nc [-46DdFhklNnrStUuvz] [-I length] [-i interval] [-O length]\n" 1519 #endif 1520 "\t [--no-tcpopt] [--sctp]\n" 1521 "\t [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n" 1522 "\t [--tun tundev] [-V rtable] [-w timeout] [-X proxy_protocol]\n" 1523 "\t [-x proxy_address[:port]] [destination] [port]\n"); 1524 if (ret) 1525 exit(1); 1526 } 1527