1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1983, 1991, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/filio.h> 33 #include <sys/ioccom.h> 34 #include <sys/param.h> 35 #include <sys/stat.h> 36 #include <sys/socket.h> 37 #include <sys/sysctl.h> 38 #include <sys/ucred.h> 39 #include <sys/uio.h> 40 #include <sys/utsname.h> 41 42 #include <ctype.h> 43 #include <err.h> 44 #include <errno.h> 45 #include <fcntl.h> 46 #include <limits.h> 47 #include <pwd.h> 48 #include <signal.h> 49 #include <stdlib.h> 50 #include <string.h> 51 #include <sysexits.h> 52 #include <syslog.h> 53 #include <unistd.h> 54 55 #include "inetd.h" 56 57 static void chargen_dg(int, struct servtab *); 58 static void chargen_stream(int, struct servtab *); 59 static void daytime_dg(int, struct servtab *); 60 static void daytime_stream(int, struct servtab *); 61 static void discard_dg(int, struct servtab *); 62 static void discard_stream(int, struct servtab *); 63 static void echo_dg(int, struct servtab *); 64 static void echo_stream(int, struct servtab *); 65 static int get_line(int, char *, int); 66 static void iderror(int, int, int, const char *); 67 static void ident_stream(int, struct servtab *); 68 static void initring(void); 69 static uint32_t machtime(void); 70 static void machtime_dg(int, struct servtab *); 71 static void machtime_stream(int, struct servtab *); 72 73 static char ring[128]; 74 static char *endring; 75 76 struct biltin biltins[] = { 77 /* Echo received data */ 78 { "echo", SOCK_STREAM, 1, -1, echo_stream }, 79 { "echo", SOCK_DGRAM, 0, 1, echo_dg }, 80 81 /* Internet /dev/null */ 82 { "discard", SOCK_STREAM, 1, -1, discard_stream }, 83 { "discard", SOCK_DGRAM, 0, 1, discard_dg }, 84 85 /* Return 32 bit time since 1900 */ 86 { "time", SOCK_STREAM, 0, -1, machtime_stream }, 87 { "time", SOCK_DGRAM, 0, 1, machtime_dg }, 88 89 /* Return human-readable time */ 90 { "daytime", SOCK_STREAM, 0, -1, daytime_stream }, 91 { "daytime", SOCK_DGRAM, 0, 1, daytime_dg }, 92 93 /* Familiar character generator */ 94 { "chargen", SOCK_STREAM, 1, -1, chargen_stream }, 95 { "chargen", SOCK_DGRAM, 0, 1, chargen_dg }, 96 97 { "tcpmux", SOCK_STREAM, 1, -1, (bi_fn_t *)tcpmux }, 98 99 { "auth", SOCK_STREAM, 1, -1, ident_stream }, 100 101 { NULL, 0, 0, 0, NULL } 102 }; 103 104 /* 105 * RFC864 Character Generator Protocol. Generates character data without 106 * any regard for input. 107 */ 108 109 static void 110 initring(void) 111 { 112 int i; 113 114 endring = ring; 115 116 for (i = 0; i <= 128; ++i) 117 if (isprint(i)) 118 *endring++ = i; 119 } 120 121 /* Character generator 122 * The RFC says that we should send back a random number of 123 * characters chosen from the range 0 to 512. We send LINESIZ+2. 124 */ 125 /* ARGSUSED */ 126 static void 127 chargen_dg(int s, struct servtab *sep) 128 { 129 struct sockaddr_storage ss; 130 static char *rs; 131 int len; 132 socklen_t size; 133 char text[LINESIZ+2]; 134 135 if (endring == NULL) 136 initring(); 137 if (rs == NULL) 138 rs = ring; 139 140 size = sizeof(ss); 141 if (recvfrom(s, text, sizeof(text), 0, 142 (struct sockaddr *)&ss, &size) < 0) 143 return; 144 145 if (check_loop((struct sockaddr *)&ss, sep)) 146 return; 147 148 if ((len = endring - rs) >= LINESIZ) 149 memmove(text, rs, LINESIZ); 150 else { 151 memmove(text, rs, len); 152 memmove(text + len, ring, LINESIZ - len); 153 } 154 if (++rs == endring) 155 rs = ring; 156 text[LINESIZ] = '\r'; 157 text[LINESIZ + 1] = '\n'; 158 (void) sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size); 159 } 160 161 /* Character generator */ 162 /* ARGSUSED */ 163 static void 164 chargen_stream(int s, struct servtab *sep) 165 { 166 int len; 167 char *rs, text[LINESIZ+2]; 168 169 inetd_setproctitle(sep->se_service, s); 170 171 if (!endring) 172 initring(); 173 174 text[LINESIZ] = '\r'; 175 text[LINESIZ + 1] = '\n'; 176 for (rs = ring;;) { 177 if ((len = endring - rs) >= LINESIZ) 178 memmove(text, rs, LINESIZ); 179 else { 180 memmove(text, rs, len); 181 memmove(text + len, ring, LINESIZ - len); 182 } 183 if (++rs == endring) 184 rs = ring; 185 if (write(s, text, sizeof(text)) != sizeof(text)) 186 break; 187 } 188 exit(0); 189 } 190 191 /* 192 * RFC867 Daytime Protocol. Sends the current date and time as an ascii 193 * character string without any regard for input. 194 */ 195 196 /* Return human-readable time of day */ 197 /* ARGSUSED */ 198 static void 199 daytime_dg(int s, struct servtab *sep) 200 { 201 char buffer[256]; 202 time_t now; 203 struct sockaddr_storage ss; 204 socklen_t size; 205 206 now = time((time_t *) 0); 207 208 size = sizeof(ss); 209 if (recvfrom(s, buffer, sizeof(buffer), 0, 210 (struct sockaddr *)&ss, &size) < 0) 211 return; 212 213 if (check_loop((struct sockaddr *)&ss, sep)) 214 return; 215 216 (void) sprintf(buffer, "%.24s\r\n", ctime(&now)); 217 (void) sendto(s, buffer, strlen(buffer), 0, 218 (struct sockaddr *)&ss, size); 219 } 220 221 /* Return human-readable time of day */ 222 /* ARGSUSED */ 223 static void 224 daytime_stream(int s, struct servtab *sep __unused) 225 { 226 char buffer[256]; 227 time_t now; 228 229 now = time((time_t *) 0); 230 231 (void) sprintf(buffer, "%.24s\r\n", ctime(&now)); 232 (void) send(s, buffer, strlen(buffer), MSG_EOF); 233 } 234 235 /* 236 * RFC863 Discard Protocol. Any data received is thrown away and no response 237 * is sent. 238 */ 239 240 /* Discard service -- ignore data */ 241 /* ARGSUSED */ 242 static void 243 discard_dg(int s, struct servtab *sep __unused) 244 { 245 char buffer[BUFSIZE]; 246 247 (void) read(s, buffer, sizeof(buffer)); 248 } 249 250 /* Discard service -- ignore data */ 251 /* ARGSUSED */ 252 static void 253 discard_stream(int s, struct servtab *sep) 254 { 255 int ret; 256 char buffer[BUFSIZE]; 257 258 inetd_setproctitle(sep->se_service, s); 259 while (1) { 260 while ((ret = read(s, buffer, sizeof(buffer))) > 0) 261 ; 262 if (ret == 0 || errno != EINTR) 263 break; 264 } 265 exit(0); 266 } 267 268 /* 269 * RFC862 Echo Protocol. Any data received is sent back to the sender as 270 * received. 271 */ 272 273 /* Echo service -- echo data back */ 274 /* ARGSUSED */ 275 static void 276 echo_dg(int s, struct servtab *sep) 277 { 278 char buffer[65536]; /* Should be sizeof(max datagram). */ 279 int i; 280 socklen_t size; 281 struct sockaddr_storage ss; 282 283 size = sizeof(ss); 284 if ((i = recvfrom(s, buffer, sizeof(buffer), 0, 285 (struct sockaddr *)&ss, &size)) < 0) 286 return; 287 288 if (check_loop((struct sockaddr *)&ss, sep)) 289 return; 290 291 (void) sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size); 292 } 293 294 /* Echo service -- echo data back */ 295 /* ARGSUSED */ 296 static void 297 echo_stream(int s, struct servtab *sep) 298 { 299 char buffer[BUFSIZE]; 300 int i; 301 302 inetd_setproctitle(sep->se_service, s); 303 while ((i = read(s, buffer, sizeof(buffer))) > 0 && 304 write(s, buffer, i) > 0) 305 ; 306 exit(0); 307 } 308 309 /* 310 * RFC1413 Identification Protocol. Given a TCP port number pair, return a 311 * character string which identifies the owner of that connection on the 312 * server's system. Extended to allow for ~/.fakeid support and ~/.noident 313 * support. 314 */ 315 316 /* RFC 1413 says the following are the only errors you can return. */ 317 #define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */ 318 #define ID_NOUSER "NO-USER" /* Port not in use/not identifable. */ 319 #define ID_HIDDEN "HIDDEN-USER" /* Hiden at user's request. */ 320 #define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */ 321 322 /* Generic ident_stream error-sending func */ 323 /* ARGSUSED */ 324 static void 325 iderror(int lport, int fport, int s, const char *er) 326 { 327 char *p; 328 329 asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er); 330 if (p == NULL) { 331 syslog(LOG_ERR, "asprintf: %m"); 332 exit(EX_OSERR); 333 } 334 send(s, p, strlen(p), MSG_EOF); 335 free(p); 336 337 exit(0); 338 } 339 340 /* Ident service (AKA "auth") */ 341 /* ARGSUSED */ 342 static void 343 ident_stream(int s, struct servtab *sep) 344 { 345 struct utsname un; 346 struct stat sb; 347 struct sockaddr_in sin4[2]; 348 #ifdef INET6 349 struct sockaddr_in6 sin6[2]; 350 #endif 351 struct sockaddr_storage ss[2]; 352 struct xucred uc; 353 struct timeval tv = { 354 10, 355 0 356 }, to; 357 struct passwd *pw = NULL; 358 fd_set fdset; 359 char buf[BUFSIZE], *p, **av, *osname = NULL, e; 360 char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */ 361 socklen_t socklen; 362 ssize_t ssize; 363 size_t size, bufsiz; 364 int c, fflag = 0, nflag = 0, rflag = 0, argc = 0; 365 int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen; 366 u_short lport, fport; 367 368 inetd_setproctitle(sep->se_service, s); 369 /* 370 * Reset getopt() since we are a fork() but not an exec() from 371 * a parent which used getopt() already. 372 */ 373 optind = 1; 374 optreset = 1; 375 /* 376 * Take the internal argument vector and count it out to make an 377 * argument count for getopt. This can be used for any internal 378 * service to read arguments and use getopt() easily. 379 */ 380 for (av = sep->se_argv; *av; av++) 381 argc++; 382 if (argc) { 383 int sec, usec; 384 size_t i; 385 u_int32_t rnd32; 386 387 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1) 388 switch (c) { 389 case 'd': 390 if (!gflag) 391 strlcpy(idbuf, optarg, sizeof(idbuf)); 392 break; 393 case 'f': 394 fflag = 1; 395 break; 396 case 'F': 397 fflag = 1; 398 Fflag=1; 399 break; 400 case 'g': 401 gflag = 1; 402 rnd32 = 0; /* Shush, compiler. */ 403 /* 404 * The number of bits in "rnd32" divided 405 * by the number of bits needed per iteration 406 * gives a more optimal way to reload the 407 * random number only when necessary. 408 * 409 * 32 bits from arc4random corresponds to 410 * about 6 base-36 digits, so we reseed evey 6. 411 */ 412 for (i = 0; i < sizeof(idbuf) - 1; i++) { 413 static const char *const base36 = 414 "0123456789" 415 "abcdefghijklmnopqrstuvwxyz"; 416 if (i % 6 == 0) 417 rnd32 = arc4random(); 418 idbuf[i] = base36[rnd32 % 36]; 419 rnd32 /= 36; 420 } 421 idbuf[i] = '\0'; 422 break; 423 case 'i': 424 iflag = 1; 425 break; 426 case 'n': 427 nflag = 1; 428 break; 429 case 'o': 430 osname = optarg; 431 break; 432 case 'r': 433 rflag = 1; 434 break; 435 case 't': 436 switch (sscanf(optarg, "%d.%d", &sec, &usec)) { 437 case 2: 438 tv.tv_usec = usec; 439 /* FALLTHROUGH */ 440 case 1: 441 tv.tv_sec = sec; 442 break; 443 default: 444 if (debug) 445 warnx("bad -t argument"); 446 break; 447 } 448 break; 449 default: 450 break; 451 } 452 } 453 if (osname == NULL) { 454 if (uname(&un) == -1) 455 iderror(0, 0, s, ID_UNKNOWN); 456 osname = un.sysname; 457 } 458 459 /* 460 * We're going to prepare for and execute reception of a 461 * packet of data from the user. The data is in the format 462 * "local_port , foreign_port\r\n" (with local being the 463 * server's port and foreign being the client's.) 464 */ 465 gettimeofday(&to, NULL); 466 to.tv_sec += tv.tv_sec; 467 to.tv_usec += tv.tv_usec; 468 if (to.tv_usec >= 1000000) { 469 to.tv_usec -= 1000000; 470 to.tv_sec++; 471 } 472 473 size = 0; 474 bufsiz = sizeof(buf) - 1; 475 FD_ZERO(&fdset); 476 while (bufsiz > 0) { 477 gettimeofday(&tv, NULL); 478 tv.tv_sec = to.tv_sec - tv.tv_sec; 479 tv.tv_usec = to.tv_usec - tv.tv_usec; 480 if (tv.tv_usec < 0) { 481 tv.tv_usec += 1000000; 482 tv.tv_sec--; 483 } 484 if (tv.tv_sec < 0) 485 break; 486 FD_SET(s, &fdset); 487 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1) 488 iderror(0, 0, s, ID_UNKNOWN); 489 if (ioctl(s, FIONREAD, &onreadlen) == -1) 490 iderror(0, 0, s, ID_UNKNOWN); 491 if ((size_t)onreadlen > bufsiz) 492 onreadlen = bufsiz; 493 ssize = read(s, &buf[size], (size_t)onreadlen); 494 if (ssize == -1) 495 iderror(0, 0, s, ID_UNKNOWN); 496 else if (ssize == 0) 497 break; 498 bufsiz -= ssize; 499 size += ssize; 500 if (memchr(&buf[size - ssize], '\n', ssize) != NULL) 501 break; 502 } 503 buf[size] = '\0'; 504 /* Read two characters, and check for a delimiting character */ 505 if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e)) 506 iderror(0, 0, s, ID_INVALID); 507 508 /* Send garbage? */ 509 if (gflag) 510 goto printit; 511 512 /* 513 * If not "real" (-r), send a HIDDEN-USER error for everything. 514 * If -d is used to set a fallback username, this is used to 515 * override it, and the fallback is returned instead. 516 */ 517 if (!rflag) { 518 if (*idbuf == '\0') 519 iderror(lport, fport, s, ID_HIDDEN); 520 goto printit; 521 } 522 523 /* 524 * We take the input and construct an array of two sockaddr_ins 525 * which contain the local address information and foreign 526 * address information, respectively, used to look up the 527 * credentials for the socket (which are returned by the 528 * sysctl "net.inet.tcp.getcred" when we call it.) 529 */ 530 socklen = sizeof(ss[0]); 531 if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1) 532 iderror(lport, fport, s, ID_UNKNOWN); 533 socklen = sizeof(ss[1]); 534 if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1) 535 iderror(lport, fport, s, ID_UNKNOWN); 536 if (ss[0].ss_family != ss[1].ss_family) 537 iderror(lport, fport, s, ID_UNKNOWN); 538 size = sizeof(uc); 539 switch (ss[0].ss_family) { 540 case AF_INET: 541 sin4[0] = *(struct sockaddr_in *)&ss[0]; 542 sin4[0].sin_port = htons(lport); 543 sin4[1] = *(struct sockaddr_in *)&ss[1]; 544 sin4[1].sin_port = htons(fport); 545 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4, 546 sizeof(sin4)) == -1) 547 getcredfail = errno; 548 break; 549 #ifdef INET6 550 case AF_INET6: 551 sin6[0] = *(struct sockaddr_in6 *)&ss[0]; 552 sin6[0].sin6_port = htons(lport); 553 sin6[1] = *(struct sockaddr_in6 *)&ss[1]; 554 sin6[1].sin6_port = htons(fport); 555 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6, 556 sizeof(sin6)) == -1) 557 getcredfail = errno; 558 break; 559 #endif 560 default: /* should not reach here */ 561 getcredfail = EAFNOSUPPORT; 562 break; 563 } 564 if (getcredfail != 0 || uc.cr_version != XUCRED_VERSION) { 565 if (*idbuf == '\0') 566 iderror(lport, fport, s, 567 getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN); 568 goto printit; 569 } 570 571 /* Look up the pw to get the username and home directory*/ 572 errno = 0; 573 pw = getpwuid(uc.cr_uid); 574 if (pw == NULL) 575 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN); 576 577 if (iflag) 578 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid); 579 else 580 strlcpy(idbuf, pw->pw_name, sizeof(idbuf)); 581 582 /* 583 * If enabled, we check for a file named ".noident" in the user's 584 * home directory. If found, we return HIDDEN-USER. 585 */ 586 if (nflag) { 587 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1) 588 iderror(lport, fport, s, ID_UNKNOWN); 589 if (lstat(p, &sb) == 0) { 590 free(p); 591 iderror(lport, fport, s, ID_HIDDEN); 592 } 593 free(p); 594 } 595 596 /* 597 * Here, if enabled, we read a user's ".fakeid" file in their 598 * home directory. It consists of a line containing the name 599 * they want. 600 */ 601 if (fflag) { 602 int fakeid_fd; 603 604 /* 605 * Here we set ourself to effectively be the user, so we don't 606 * open any files we have no permission to open, especially 607 * symbolic links to sensitive root-owned files or devices. 608 */ 609 if (initgroups(pw->pw_name, pw->pw_gid) == -1) 610 iderror(lport, fport, s, ID_UNKNOWN); 611 if (seteuid(pw->pw_uid) == -1) 612 iderror(lport, fport, s, ID_UNKNOWN); 613 /* 614 * We can't stat() here since that would be a race 615 * condition. 616 * Therefore, we open the file we have permissions to open 617 * and if it's not a regular file, we close it and end up 618 * returning the user's real username. 619 */ 620 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1) 621 iderror(lport, fport, s, ID_UNKNOWN); 622 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK); 623 free(p); 624 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 || 625 !S_ISREG(sb.st_mode)) 626 goto fakeid_fail; 627 628 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0) 629 goto fakeid_fail; 630 buf[ssize] = '\0'; 631 632 /* 633 * Usually, the file will have the desired identity 634 * in the form "identity\n". Allow for leading white 635 * space and trailing white space/end of line. 636 */ 637 p = buf; 638 p += strspn(p, " \t"); 639 p[strcspn(p, " \t\r\n")] = '\0'; 640 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */ 641 p[MAXLOGNAME - 1] = '\0'; 642 643 /* 644 * If the name is a zero-length string or matches it 645 * the id or name of another user (unless permitted by -F) 646 * then it is invalid. 647 */ 648 if (*p == '\0') 649 goto fakeid_fail; 650 if (!Fflag) { 651 if (iflag) { 652 const char *errstr; 653 uid_t uid; 654 655 uid = strtonum(p, 0, UID_MAX, &errstr); 656 if (errstr != NULL) 657 goto fakeid_fail; 658 659 if (getpwuid(uid) != NULL) 660 goto fakeid_fail; 661 } else { 662 if (getpwnam(p) != NULL) 663 goto fakeid_fail; 664 } 665 } 666 667 strlcpy(idbuf, p, sizeof(idbuf)); 668 669 fakeid_fail: 670 if (fakeid_fd != -1) 671 close(fakeid_fd); 672 } 673 674 printit: 675 /* Finally, we make and send the reply. */ 676 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname, 677 idbuf) == -1) { 678 syslog(LOG_ERR, "asprintf: %m"); 679 exit(EX_OSERR); 680 } 681 send(s, p, strlen(p), MSG_EOF); 682 free(p); 683 684 exit(0); 685 } 686 687 /* 688 * RFC738/868 Time Server. 689 * Return a machine readable date and time, in the form of the 690 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday 691 * returns the number of seconds since midnight, Jan 1, 1970, 692 * we must add 2208988800 seconds to this figure to make up for 693 * some seventy years Bell Labs was asleep. 694 */ 695 696 static uint32_t 697 machtime(void) 698 { 699 700 #define OFFSET ((uint32_t)25567 * 24*60*60) 701 return (htonl((uint32_t)(time(NULL) + OFFSET))); 702 #undef OFFSET 703 } 704 705 /* ARGSUSED */ 706 static void 707 machtime_dg(int s, struct servtab *sep) 708 { 709 uint32_t result; 710 struct sockaddr_storage ss; 711 socklen_t size; 712 713 size = sizeof(ss); 714 if (recvfrom(s, (char *)&result, sizeof(result), 0, 715 (struct sockaddr *)&ss, &size) < 0) 716 return; 717 718 if (check_loop((struct sockaddr *)&ss, sep)) 719 return; 720 721 result = machtime(); 722 (void) sendto(s, (char *) &result, sizeof(result), 0, 723 (struct sockaddr *)&ss, size); 724 } 725 726 /* ARGSUSED */ 727 static void 728 machtime_stream(int s, struct servtab *sep __unused) 729 { 730 uint32_t result; 731 732 result = machtime(); 733 (void) send(s, (char *) &result, sizeof(result), MSG_EOF); 734 } 735 736 /* 737 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to 738 * services based on the service name sent. 739 * 740 * Based on TCPMUX.C by Mark K. Lottor November 1988 741 * sri-nic::ps:<mkl>tcpmux.c 742 */ 743 744 #define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */ 745 #define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1) 746 747 static int /* # of characters up to \r,\n or \0 */ 748 get_line(int fd, char *buf, int len) 749 { 750 int count = 0, n; 751 struct sigaction sa; 752 753 sa.sa_flags = 0; 754 sigemptyset(&sa.sa_mask); 755 sa.sa_handler = SIG_DFL; 756 sigaction(SIGALRM, &sa, (struct sigaction *)0); 757 do { 758 alarm(10); 759 n = read(fd, buf, len-count); 760 alarm(0); 761 if (n == 0) 762 return (count); 763 if (n < 0) 764 return (-1); 765 while (--n >= 0) { 766 if (*buf == '\r' || *buf == '\n' || *buf == '\0') 767 return (count); 768 count++; 769 buf++; 770 } 771 } while (count < len); 772 return (count); 773 } 774 775 struct servtab * 776 tcpmux(int s) 777 { 778 struct servtab *sep; 779 char service[MAX_SERV_LEN+1]; 780 int len; 781 782 /* Get requested service name */ 783 if ((len = get_line(s, service, MAX_SERV_LEN)) < 0) { 784 strwrite(s, "-Error reading service name\r\n"); 785 return (NULL); 786 } 787 service[len] = '\0'; 788 789 if (debug) 790 warnx("tcpmux: someone wants %s", service); 791 792 /* 793 * Help is a required command, and lists available services, 794 * one per line. 795 */ 796 if (!strcasecmp(service, "help")) { 797 for (sep = servtab; sep; sep = sep->se_next) { 798 if (!ISMUX(sep)) 799 continue; 800 (void)write(s,sep->se_service,strlen(sep->se_service)); 801 strwrite(s, "\r\n"); 802 } 803 return (NULL); 804 } 805 806 /* Try matching a service in inetd.conf with the request */ 807 for (sep = servtab; sep; sep = sep->se_next) { 808 if (!ISMUX(sep)) 809 continue; 810 if (!strcasecmp(service, sep->se_service)) { 811 if (ISMUXPLUS(sep)) { 812 strwrite(s, "+Go\r\n"); 813 } 814 return (sep); 815 } 816 } 817 strwrite(s, "-Service not available\r\n"); 818 return (NULL); 819 } 820