1 /*- 2 * Copyright (c) 1983, 1991, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 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 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/usr.sbin/inetd/builtins.c,v 1.19.2.7 2002/07/22 14:05:56 fanf Exp $ 27 * $DragonFly: src/usr.sbin/inetd/builtins.c,v 1.4 2003/11/16 15:17:36 eirikn Exp $ 28 * 29 */ 30 31 #include <sys/filio.h> 32 #include <sys/ioccom.h> 33 #include <sys/param.h> 34 #include <sys/stat.h> 35 #include <sys/socket.h> 36 #include <sys/sysctl.h> 37 #include <sys/ucred.h> 38 #include <sys/uio.h> 39 #include <sys/utsname.h> 40 41 #include <ctype.h> 42 #include <err.h> 43 #include <errno.h> 44 #include <fcntl.h> 45 #include <limits.h> 46 #include <pwd.h> 47 #include <signal.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <sysexits.h> 51 #include <syslog.h> 52 #include <unistd.h> 53 54 #include "inetd.h" 55 56 void chargen_dg(int, struct servtab *); 57 void chargen_stream(int, struct servtab *); 58 void daytime_dg(int, struct servtab *); 59 void daytime_stream(int, struct servtab *); 60 void discard_dg(int, struct servtab *); 61 void discard_stream(int, struct servtab *); 62 void echo_dg(int, struct servtab *); 63 void echo_stream(int, struct servtab *); 64 static int getline(int, char *, int); 65 void iderror(int, int, int, const char *); 66 void ident_stream(int, struct servtab *); 67 void initring(void); 68 unsigned long machtime(void); 69 void machtime_dg(int, struct servtab *); 70 void machtime_stream(int, struct servtab *); 71 72 char ring[128]; 73 char *endring; 74 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 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 /* ARGSUSED */ 122 void 123 chargen_dg(int s, struct servtab *sep) /* Character generator */ 124 { 125 struct sockaddr_storage ss; 126 static char *rs; 127 int len; 128 socklen_t size; 129 char text[LINESIZ+2]; 130 131 if (endring == 0) { 132 initring(); 133 rs = ring; 134 } 135 136 size = sizeof(ss); 137 if (recvfrom(s, text, sizeof(text), 0, 138 (struct sockaddr *)&ss, &size) < 0) 139 return; 140 141 if (check_loop((struct sockaddr *)&ss, sep)) 142 return; 143 144 if ((len = endring - rs) >= LINESIZ) 145 memmove(text, rs, LINESIZ); 146 else { 147 memmove(text, rs, len); 148 memmove(text + len, ring, LINESIZ - len); 149 } 150 if (++rs == endring) 151 rs = ring; 152 text[LINESIZ] = '\r'; 153 text[LINESIZ + 1] = '\n'; 154 (void) sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size); 155 } 156 157 /* ARGSUSED */ 158 void 159 chargen_stream(int s, struct servtab *sep) /* Character generator */ 160 { 161 int len; 162 char *rs, text[LINESIZ+2]; 163 164 inetd_setproctitle(sep->se_service, s); 165 166 if (!endring) { 167 initring(); 168 rs = ring; 169 } 170 171 text[LINESIZ] = '\r'; 172 text[LINESIZ + 1] = '\n'; 173 for (rs = ring;;) { 174 if ((len = endring - rs) >= LINESIZ) 175 memmove(text, rs, LINESIZ); 176 else { 177 memmove(text, rs, len); 178 memmove(text + len, ring, LINESIZ - len); 179 } 180 if (++rs == endring) 181 rs = ring; 182 if (write(s, text, sizeof(text)) != sizeof(text)) 183 break; 184 } 185 exit(0); 186 } 187 188 /* 189 * RFC867 Daytime Protocol. Sends the current date and time as an ascii 190 * character string without any regard for input. 191 */ 192 193 /* ARGSUSED */ 194 void 195 daytime_dg(int s, struct servtab *sep) /* Return human-readable time of day */ 196 { 197 char buffer[256]; 198 time_t now; 199 struct sockaddr_storage ss; 200 socklen_t size; 201 202 now = time((time_t *) 0); 203 204 size = sizeof(ss); 205 if (recvfrom(s, buffer, sizeof(buffer), 0, 206 (struct sockaddr *)&ss, &size) < 0) 207 return; 208 209 if (check_loop((struct sockaddr *)&ss, sep)) 210 return; 211 212 (void) sprintf(buffer, "%.24s\r\n", ctime(&now)); 213 (void) sendto(s, buffer, strlen(buffer), 0, 214 (struct sockaddr *)&ss, size); 215 } 216 217 /* ARGSUSED */ 218 void 219 daytime_stream(int s, struct servtab *sep __unused) /* Return human-readable time of day */ 220 { 221 char buffer[256]; 222 time_t now; 223 224 now = time((time_t *) 0); 225 226 (void) sprintf(buffer, "%.24s\r\n", ctime(&now)); 227 (void) send(s, buffer, strlen(buffer), MSG_EOF); 228 } 229 230 /* 231 * RFC863 Discard Protocol. Any data received is thrown away and no response 232 * is sent. 233 */ 234 235 /* ARGSUSED */ 236 void 237 discard_dg(int s, struct servtab *sep __unused) /* Discard service -- ignore data */ 238 { 239 char buffer[BUFSIZE]; 240 241 (void) read(s, buffer, sizeof(buffer)); 242 } 243 244 /* ARGSUSED */ 245 void 246 discard_stream(int s, struct servtab *sep) /* Discard service -- ignore data */ 247 { 248 int ret; 249 char buffer[BUFSIZE]; 250 251 inetd_setproctitle(sep->se_service, s); 252 while (1) { 253 while ((ret = read(s, buffer, sizeof(buffer))) > 0) 254 ; 255 if (ret == 0 || errno != EINTR) 256 break; 257 } 258 exit(0); 259 } 260 261 /* 262 * RFC862 Echo Protocol. Any data received is sent back to the sender as 263 * received. 264 */ 265 266 /* ARGSUSED */ 267 void 268 echo_dg(int s, struct servtab *sep) /* Echo service -- echo data back */ 269 { 270 char buffer[65536]; /* Should be sizeof(max datagram). */ 271 int i; 272 socklen_t size; 273 struct sockaddr_storage ss; 274 275 size = sizeof(ss); 276 if ((i = recvfrom(s, buffer, sizeof(buffer), 0, 277 (struct sockaddr *)&ss, &size)) < 0) 278 return; 279 280 if (check_loop((struct sockaddr *)&ss, sep)) 281 return; 282 283 (void) sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size); 284 } 285 286 /* ARGSUSED */ 287 void 288 echo_stream(int s, struct servtab *sep) /* Echo service -- echo data back */ 289 { 290 char buffer[BUFSIZE]; 291 int i; 292 293 inetd_setproctitle(sep->se_service, s); 294 while ((i = read(s, buffer, sizeof(buffer))) > 0 && 295 write(s, buffer, i) > 0) 296 ; 297 exit(0); 298 } 299 300 /* 301 * RFC1413 Identification Protocol. Given a TCP port number pair, return a 302 * character string which identifies the owner of that connection on the 303 * server's system. Extended to allow for ~/.fakeid support and ~/.noident 304 * support. 305 */ 306 307 /* RFC 1413 says the following are the only errors you can return. */ 308 #define ID_INVALID "INVALID-PORT" /* Port number improperly specified. */ 309 #define ID_NOUSER "NO-USER" /* Port not in use/not identifable. */ 310 #define ID_HIDDEN "HIDDEN-USER" /* Hiden at user's request. */ 311 #define ID_UNKNOWN "UNKNOWN-ERROR" /* Everything else. */ 312 313 /* ARGSUSED */ 314 void 315 iderror(int lport, int fport, int s, const char *er) /* Generic ident_stream error-sending func */ 316 { 317 char *p; 318 319 asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, er); 320 if (p == NULL) { 321 syslog(LOG_ERR, "asprintf: %m"); 322 exit(EX_OSERR); 323 } 324 send(s, p, strlen(p), MSG_EOF); 325 free(p); 326 327 exit(0); 328 } 329 330 /* ARGSUSED */ 331 void 332 ident_stream(int s, struct servtab *sep) /* Ident service (AKA "auth") */ 333 { 334 struct utsname un; 335 struct stat sb; 336 struct sockaddr_in sin4[2]; 337 #ifdef INET6 338 struct sockaddr_in6 sin6[2]; 339 #endif 340 struct sockaddr_storage ss[2]; 341 struct ucred uc; 342 struct timeval tv = { 343 10, 344 0 345 }, to; 346 struct passwd *pw = NULL; 347 fd_set fdset; 348 char buf[BUFSIZE], *p, **av, *osname = NULL, e; 349 char idbuf[MAXLOGNAME] = ""; /* Big enough to hold uid in decimal. */ 350 socklen_t socklen; 351 ssize_t ssize; 352 size_t size, bufsiz; 353 int c, fflag = 0, nflag = 0, rflag = 0, argc = 0; 354 int gflag = 0, iflag = 0, Fflag = 0, getcredfail = 0, onreadlen; 355 u_short lport, fport; 356 357 inetd_setproctitle(sep->se_service, s); 358 /* 359 * Reset getopt() since we are a fork() but not an exec() from 360 * a parent which used getopt() already. 361 */ 362 optind = 1; 363 optreset = 1; 364 /* 365 * Take the internal argument vector and count it out to make an 366 * argument count for getopt. This can be used for any internal 367 * service to read arguments and use getopt() easily. 368 */ 369 for (av = sep->se_argv; *av; av++) 370 argc++; 371 if (argc) { 372 int sec, usec; 373 size_t i; 374 u_int32_t rnd32; 375 376 while ((c = getopt(argc, sep->se_argv, "d:fFgino:rt:")) != -1) 377 switch (c) { 378 case 'd': 379 if (!gflag) 380 strlcpy(idbuf, optarg, sizeof(idbuf)); 381 break; 382 case 'f': 383 fflag = 1; 384 break; 385 case 'F': 386 fflag = 1; 387 Fflag=1; 388 break; 389 case 'g': 390 gflag = 1; 391 rnd32 = 0; /* Shush, compiler. */ 392 /* 393 * The number of bits in "rnd32" divided 394 * by the number of bits needed per iteration 395 * gives a more optimal way to reload the 396 * random number only when necessary. 397 * 398 * 32 bits from arc4random corresponds to 399 * about 6 base-36 digits, so we reseed evey 6. 400 */ 401 for (i = 0; i < sizeof(idbuf) - 1; i++) { 402 static const char *const base36 = 403 "0123456789" 404 "abcdefghijklmnopqrstuvwxyz"; 405 if (i % 6 == 0) 406 rnd32 = arc4random(); 407 idbuf[i] = base36[rnd32 % 36]; 408 rnd32 /= 36; 409 } 410 idbuf[i] = '\0'; 411 break; 412 case 'i': 413 iflag = 1; 414 break; 415 case 'n': 416 nflag = 1; 417 break; 418 case 'o': 419 osname = optarg; 420 break; 421 case 'r': 422 rflag = 1; 423 break; 424 case 't': 425 switch (sscanf(optarg, "%d.%d", &sec, &usec)) { 426 case 2: 427 tv.tv_usec = usec; 428 /* FALLTHROUGH */ 429 case 1: 430 tv.tv_sec = sec; 431 break; 432 default: 433 if (debug) 434 warnx("bad -t argument"); 435 break; 436 } 437 break; 438 default: 439 break; 440 } 441 } 442 if (osname == NULL) { 443 if (uname(&un) == -1) 444 iderror(0, 0, s, ID_UNKNOWN); 445 osname = un.sysname; 446 } 447 448 /* 449 * We're going to prepare for and execute reception of a 450 * packet of data from the user. The data is in the format 451 * "local_port , foreign_port\r\n" (with local being the 452 * server's port and foreign being the client's.) 453 */ 454 gettimeofday(&to, NULL); 455 to.tv_sec += tv.tv_sec; 456 to.tv_usec += tv.tv_usec; 457 if (to.tv_usec >= 1000000) { 458 to.tv_usec -= 1000000; 459 to.tv_sec++; 460 } 461 462 size = 0; 463 bufsiz = sizeof(buf) - 1; 464 FD_ZERO(&fdset); 465 while (bufsiz > 0) { 466 gettimeofday(&tv, NULL); 467 tv.tv_sec = to.tv_sec - tv.tv_sec; 468 tv.tv_usec = to.tv_usec - tv.tv_usec; 469 if (tv.tv_usec < 0) { 470 tv.tv_usec += 1000000; 471 tv.tv_sec--; 472 } 473 if (tv.tv_sec < 0) 474 break; 475 FD_SET(s, &fdset); 476 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1) 477 iderror(0, 0, s, ID_UNKNOWN); 478 if (ioctl(s, FIONREAD, &onreadlen) == -1) 479 iderror(0, 0, s, ID_UNKNOWN); 480 if ((size_t)onreadlen > bufsiz) 481 onreadlen = bufsiz; 482 ssize = read(s, &buf[size], (size_t)onreadlen); 483 if (ssize == -1) 484 iderror(0, 0, s, ID_UNKNOWN); 485 else if (ssize == 0) 486 break; 487 bufsiz -= ssize; 488 size += ssize; 489 if (memchr(&buf[size - ssize], '\n', ssize) != NULL) 490 break; 491 } 492 buf[size] = '\0'; 493 /* Read two characters, and check for a delimiting character */ 494 if (sscanf(buf, "%hu , %hu%c", &lport, &fport, &e) != 3 || isdigit(e)) 495 iderror(0, 0, s, ID_INVALID); 496 497 /* Send garbage? */ 498 if (gflag) 499 goto printit; 500 501 /* 502 * If not "real" (-r), send a HIDDEN-USER error for everything. 503 * If -d is used to set a fallback username, this is used to 504 * override it, and the fallback is returned instead. 505 */ 506 if (!rflag) { 507 if (*idbuf == '\0') 508 iderror(lport, fport, s, ID_HIDDEN); 509 goto printit; 510 } 511 512 /* 513 * We take the input and construct an array of two sockaddr_ins 514 * which contain the local address information and foreign 515 * address information, respectively, used to look up the 516 * credentials for the socket (which are returned by the 517 * sysctl "net.inet.tcp.getcred" when we call it.) 518 */ 519 socklen = sizeof(ss[0]); 520 if (getsockname(s, (struct sockaddr *)&ss[0], &socklen) == -1) 521 iderror(lport, fport, s, ID_UNKNOWN); 522 socklen = sizeof(ss[1]); 523 if (getpeername(s, (struct sockaddr *)&ss[1], &socklen) == -1) 524 iderror(lport, fport, s, ID_UNKNOWN); 525 if (ss[0].ss_family != ss[1].ss_family) 526 iderror(lport, fport, s, ID_UNKNOWN); 527 size = sizeof(uc); 528 switch (ss[0].ss_family) { 529 case AF_INET: 530 sin4[0] = *(struct sockaddr_in *)&ss[0]; 531 sin4[0].sin_port = htons(lport); 532 sin4[1] = *(struct sockaddr_in *)&ss[1]; 533 sin4[1].sin_port = htons(fport); 534 if (sysctlbyname("net.inet.tcp.getcred", &uc, &size, sin4, 535 sizeof(sin4)) == -1) 536 getcredfail = errno; 537 break; 538 #ifdef INET6 539 case AF_INET6: 540 sin6[0] = *(struct sockaddr_in6 *)&ss[0]; 541 sin6[0].sin6_port = htons(lport); 542 sin6[1] = *(struct sockaddr_in6 *)&ss[1]; 543 sin6[1].sin6_port = htons(fport); 544 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &size, sin6, 545 sizeof(sin6)) == -1) 546 getcredfail = errno; 547 break; 548 #endif 549 default: /* should not reach here */ 550 getcredfail = EAFNOSUPPORT; 551 break; 552 } 553 if (getcredfail != 0) { 554 if (*idbuf == '\0') 555 iderror(lport, fport, s, 556 getcredfail == ENOENT ? ID_NOUSER : ID_UNKNOWN); 557 goto printit; 558 } 559 560 /* Look up the pw to get the username and home directory*/ 561 errno = 0; 562 pw = getpwuid(uc.cr_uid); 563 if (pw == NULL) 564 iderror(lport, fport, s, errno == 0 ? ID_NOUSER : ID_UNKNOWN); 565 566 if (iflag) 567 snprintf(idbuf, sizeof(idbuf), "%u", (unsigned)pw->pw_uid); 568 else 569 strlcpy(idbuf, pw->pw_name, sizeof(idbuf)); 570 571 /* 572 * If enabled, we check for a file named ".noident" in the user's 573 * home directory. If found, we return HIDDEN-USER. 574 */ 575 if (nflag) { 576 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1) 577 iderror(lport, fport, s, ID_UNKNOWN); 578 if (lstat(p, &sb) == 0) { 579 free(p); 580 iderror(lport, fport, s, ID_HIDDEN); 581 } 582 free(p); 583 } 584 585 /* 586 * Here, if enabled, we read a user's ".fakeid" file in their 587 * home directory. It consists of a line containing the name 588 * they want. 589 */ 590 if (fflag) { 591 int fakeid_fd; 592 593 /* 594 * Here we set ourself to effectively be the user, so we don't 595 * open any files we have no permission to open, especially 596 * symbolic links to sensitive root-owned files or devices. 597 */ 598 if (initgroups(pw->pw_name, pw->pw_gid) == -1) 599 iderror(lport, fport, s, ID_UNKNOWN); 600 if (seteuid(pw->pw_uid) == -1) 601 iderror(lport, fport, s, ID_UNKNOWN); 602 /* 603 * We can't stat() here since that would be a race 604 * condition. 605 * Therefore, we open the file we have permissions to open 606 * and if it's not a regular file, we close it and end up 607 * returning the user's real username. 608 */ 609 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1) 610 iderror(lport, fport, s, ID_UNKNOWN); 611 fakeid_fd = open(p, O_RDONLY | O_NONBLOCK); 612 free(p); 613 if (fakeid_fd == -1 || fstat(fakeid_fd, &sb) == -1 || 614 !S_ISREG(sb.st_mode)) 615 goto fakeid_fail; 616 617 if ((ssize = read(fakeid_fd, buf, sizeof(buf) - 1)) < 0) 618 goto fakeid_fail; 619 buf[ssize] = '\0'; 620 621 /* 622 * Usually, the file will have the desired identity 623 * in the form "identity\n". Allow for leading white 624 * space and trailing white space/end of line. 625 */ 626 p = buf; 627 p += strspn(p, " \t"); 628 p[strcspn(p, " \t\r\n")] = '\0'; 629 if (strlen(p) > MAXLOGNAME - 1) /* Too long (including nul)? */ 630 p[MAXLOGNAME - 1] = '\0'; 631 632 /* 633 * If the name is a zero-length string or matches it 634 * the id or name of another user (unless permitted by -F) 635 * then it is invalid. 636 */ 637 if (*p == '\0') 638 goto fakeid_fail; 639 if (!Fflag) { 640 if (iflag) { 641 if (p[strspn(p, "0123456789")] == '\0' && 642 getpwuid(atoi(p)) != NULL) 643 goto fakeid_fail; 644 } else { 645 if (getpwnam(p) != NULL) 646 goto fakeid_fail; 647 } 648 } 649 650 strlcpy(idbuf, p, sizeof(idbuf)); 651 652 fakeid_fail: 653 if (fakeid_fd != -1) 654 close(fakeid_fd); 655 } 656 657 printit: 658 /* Finally, we make and send the reply. */ 659 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname, 660 idbuf) == -1) { 661 syslog(LOG_ERR, "asprintf: %m"); 662 exit(EX_OSERR); 663 } 664 send(s, p, strlen(p), MSG_EOF); 665 free(p); 666 667 exit(0); 668 } 669 670 /* 671 * RFC738 Time Server. 672 * Return a machine readable date and time, in the form of the 673 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday 674 * returns the number of seconds since midnight, Jan 1, 1970, 675 * we must add 2208988800 seconds to this figure to make up for 676 * some seventy years Bell Labs was asleep. 677 */ 678 679 unsigned long 680 machtime(void) 681 { 682 struct timeval tv; 683 684 if (gettimeofday(&tv, (struct timezone *)NULL) < 0) { 685 if (debug) 686 warnx("unable to get time of day"); 687 return (0L); 688 } 689 #define OFFSET ((u_long)25567 * 24*60*60) 690 return (htonl((long)(tv.tv_sec + OFFSET))); 691 #undef OFFSET 692 } 693 694 /* ARGSUSED */ 695 void 696 machtime_dg(int s, struct servtab *sep) 697 { 698 unsigned long result; 699 struct sockaddr_storage ss; 700 socklen_t size; 701 702 size = sizeof(ss); 703 if (recvfrom(s, (char *)&result, sizeof(result), 0, 704 (struct sockaddr *)&ss, &size) < 0) 705 return; 706 707 if (check_loop((struct sockaddr *)&ss, sep)) 708 return; 709 710 result = machtime(); 711 (void) sendto(s, (char *) &result, sizeof(result), 0, 712 (struct sockaddr *)&ss, size); 713 } 714 715 /* ARGSUSED */ 716 void 717 machtime_stream(int s, struct servtab *sep __unused) 718 { 719 unsigned long result; 720 721 result = machtime(); 722 (void) send(s, (char *) &result, sizeof(result), MSG_EOF); 723 } 724 725 /* 726 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to 727 * services based on the service name sent. 728 * 729 * Based on TCPMUX.C by Mark K. Lottor November 1988 730 * sri-nic::ps:<mkl>tcpmux.c 731 */ 732 733 #define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */ 734 #define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1) 735 736 static int /* # of characters upto \r,\n or \0 */ 737 getline(int fd, char *buf, int len) 738 { 739 int count = 0, n; 740 struct sigaction sa; 741 742 sa.sa_flags = 0; 743 sigemptyset(&sa.sa_mask); 744 sa.sa_handler = SIG_DFL; 745 sigaction(SIGALRM, &sa, (struct sigaction *)0); 746 do { 747 alarm(10); 748 n = read(fd, buf, len-count); 749 alarm(0); 750 if (n == 0) 751 return (count); 752 if (n < 0) 753 return (-1); 754 while (--n >= 0) { 755 if (*buf == '\r' || *buf == '\n' || *buf == '\0') 756 return (count); 757 count++; 758 buf++; 759 } 760 } while (count < len); 761 return (count); 762 } 763 764 struct servtab * 765 tcpmux(int s) 766 { 767 struct servtab *sep; 768 char service[MAX_SERV_LEN+1]; 769 int len; 770 771 /* Get requested service name */ 772 if ((len = getline(s, service, MAX_SERV_LEN)) < 0) { 773 strwrite(s, "-Error reading service name\r\n"); 774 return (NULL); 775 } 776 service[len] = '\0'; 777 778 if (debug) 779 warnx("tcpmux: someone wants %s", service); 780 781 /* 782 * Help is a required command, and lists available services, 783 * one per line. 784 */ 785 if (!strcasecmp(service, "help")) { 786 for (sep = servtab; sep; sep = sep->se_next) { 787 if (!ISMUX(sep)) 788 continue; 789 (void)write(s,sep->se_service,strlen(sep->se_service)); 790 strwrite(s, "\r\n"); 791 } 792 return (NULL); 793 } 794 795 /* Try matching a service in inetd.conf with the request */ 796 for (sep = servtab; sep; sep = sep->se_next) { 797 if (!ISMUX(sep)) 798 continue; 799 if (!strcasecmp(service, sep->se_service)) { 800 if (ISMUXPLUS(sep)) { 801 strwrite(s, "+Go\r\n"); 802 } 803 return (sep); 804 } 805 } 806 strwrite(s, "-Service not available\r\n"); 807 return (NULL); 808 } 809