builtins.c revision 61098
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: head/usr.sbin/inetd/builtins.c 61098 2000-05-30 18:32:58Z jhb $ 27 * 28 */ 29 30#include <sys/filio.h> 31#include <sys/ioccom.h> 32#include <sys/param.h> 33#include <sys/stat.h> 34#include <sys/socket.h> 35#include <sys/sysctl.h> 36#include <sys/ucred.h> 37#include <sys/uio.h> 38#include <sys/utsname.h> 39 40#include <ctype.h> 41#include <err.h> 42#include <errno.h> 43#include <limits.h> 44#include <pwd.h> 45#include <signal.h> 46#include <stdlib.h> 47#include <string.h> 48#include <sysexits.h> 49#include <syslog.h> 50#include <unistd.h> 51 52#include "inetd.h" 53 54extern int debug; 55extern struct servtab *servtab; 56 57char ring[128]; 58char *endring; 59 60int check_loop __P((struct sockaddr *, struct servtab *sep)); 61void inetd_setproctitle __P((char *, int)); 62 63struct biltin biltins[] = { 64 /* Echo received data */ 65 { "echo", SOCK_STREAM, 1, -1, echo_stream }, 66 { "echo", SOCK_DGRAM, 0, 1, echo_dg }, 67 68 /* Internet /dev/null */ 69 { "discard", SOCK_STREAM, 1, -1, discard_stream }, 70 { "discard", SOCK_DGRAM, 0, 1, discard_dg }, 71 72 /* Return 32 bit time since 1970 */ 73 { "time", SOCK_STREAM, 0, -1, machtime_stream }, 74 { "time", SOCK_DGRAM, 0, 1, machtime_dg }, 75 76 /* Return human-readable time */ 77 { "daytime", SOCK_STREAM, 0, -1, daytime_stream }, 78 { "daytime", SOCK_DGRAM, 0, 1, daytime_dg }, 79 80 /* Familiar character generator */ 81 { "chargen", SOCK_STREAM, 1, -1, chargen_stream }, 82 { "chargen", SOCK_DGRAM, 0, 1, chargen_dg }, 83 84 { "tcpmux", SOCK_STREAM, 1, -1, (void (*)())tcpmux }, 85 86 { "auth", SOCK_STREAM, 1, -1, ident_stream }, 87 88 { NULL } 89}; 90 91/* 92 * RFC864 Character Generator Protocol. Generates character data without 93 * any regard for input. 94 */ 95 96void 97initring() 98{ 99 int i; 100 101 endring = ring; 102 103 for (i = 0; i <= 128; ++i) 104 if (isprint(i)) 105 *endring++ = i; 106} 107 108/* ARGSUSED */ 109void 110chargen_dg(s, sep) /* Character generator */ 111 int s; 112 struct servtab *sep; 113{ 114 struct sockaddr_storage ss; 115 static char *rs; 116 int len; 117 socklen_t size; 118 char text[LINESIZ+2]; 119 120 if (endring == 0) { 121 initring(); 122 rs = ring; 123 } 124 125 size = sizeof(ss); 126 if (recvfrom(s, text, sizeof(text), 0, 127 (struct sockaddr *)&ss, &size) < 0) 128 return; 129 130 if (check_loop((struct sockaddr *)&ss, sep)) 131 return; 132 133 if ((len = endring - rs) >= LINESIZ) 134 memmove(text, rs, LINESIZ); 135 else { 136 memmove(text, rs, len); 137 memmove(text + len, ring, LINESIZ - len); 138 } 139 if (++rs == endring) 140 rs = ring; 141 text[LINESIZ] = '\r'; 142 text[LINESIZ + 1] = '\n'; 143 (void) sendto(s, text, sizeof(text), 0, (struct sockaddr *)&ss, size); 144} 145 146/* ARGSUSED */ 147void 148chargen_stream(s, sep) /* Character generator */ 149 int s; 150 struct servtab *sep; 151{ 152 int len; 153 char *rs, text[LINESIZ+2]; 154 155 inetd_setproctitle(sep->se_service, s); 156 157 if (!endring) { 158 initring(); 159 rs = ring; 160 } 161 162 text[LINESIZ] = '\r'; 163 text[LINESIZ + 1] = '\n'; 164 for (rs = ring;;) { 165 if ((len = endring - rs) >= LINESIZ) 166 memmove(text, rs, LINESIZ); 167 else { 168 memmove(text, rs, len); 169 memmove(text + len, ring, LINESIZ - len); 170 } 171 if (++rs == endring) 172 rs = ring; 173 if (write(s, text, sizeof(text)) != sizeof(text)) 174 break; 175 } 176 exit(0); 177} 178 179/* 180 * RFC867 Daytime Protocol. Sends the current date and time as an ascii 181 * character string without any regard for input. 182 */ 183 184/* ARGSUSED */ 185void 186daytime_dg(s, sep) /* Return human-readable time of day */ 187 int s; 188 struct servtab *sep; 189{ 190 char buffer[256]; 191 time_t clock; 192 struct sockaddr_storage ss; 193 socklen_t size; 194 195 clock = time((time_t *) 0); 196 197 size = sizeof(ss); 198 if (recvfrom(s, buffer, sizeof(buffer), 0, 199 (struct sockaddr *)&ss, &size) < 0) 200 return; 201 202 if (check_loop((struct sockaddr *)&ss, sep)) 203 return; 204 205 (void) sprintf(buffer, "%.24s\r\n", ctime(&clock)); 206 (void) sendto(s, buffer, strlen(buffer), 0, 207 (struct sockaddr *)&ss, size); 208} 209 210/* ARGSUSED */ 211void 212daytime_stream(s, sep) /* Return human-readable time of day */ 213 int s; 214 struct servtab *sep; 215{ 216 char buffer[256]; 217 time_t clock; 218 219 clock = time((time_t *) 0); 220 221 (void) sprintf(buffer, "%.24s\r\n", ctime(&clock)); 222 (void) send(s, buffer, strlen(buffer), MSG_EOF); 223} 224 225/* 226 * RFC863 Discard Protocol. Any data received is thrown away and no response 227 * is sent. 228 */ 229 230/* ARGSUSED */ 231void 232discard_dg(s, sep) /* Discard service -- ignore data */ 233 int s; 234 struct servtab *sep; 235{ 236 char buffer[BUFSIZE]; 237 238 (void) read(s, buffer, sizeof(buffer)); 239} 240 241/* ARGSUSED */ 242void 243discard_stream(s, sep) /* Discard service -- ignore data */ 244 int s; 245 struct servtab *sep; 246{ 247 int ret; 248 char buffer[BUFSIZE]; 249 250 inetd_setproctitle(sep->se_service, s); 251 while (1) { 252 while ((ret = read(s, buffer, sizeof(buffer))) > 0) 253 ; 254 if (ret == 0 || errno != EINTR) 255 break; 256 } 257 exit(0); 258} 259 260/* 261 * RFC862 Echo Protocol. Any data received is sent back to the sender as 262 * received. 263 */ 264 265/* ARGSUSED */ 266void 267echo_dg(s, sep) /* Echo service -- echo data back */ 268 int s; 269 struct servtab *sep; 270{ 271 char buffer[BUFSIZE]; 272 int i; 273 socklen_t size; 274 struct sockaddr_storage ss; 275 276 size = sizeof(ss); 277 if ((i = recvfrom(s, buffer, sizeof(buffer), 0, 278 (struct sockaddr *)&ss, &size)) < 0) 279 return; 280 281 if (check_loop((struct sockaddr *)&ss, sep)) 282 return; 283 284 (void) sendto(s, buffer, i, 0, (struct sockaddr *)&ss, size); 285} 286 287/* ARGSUSED */ 288void 289echo_stream(s, sep) /* Echo service -- echo data back */ 290 int s; 291 struct servtab *sep; 292{ 293 char buffer[BUFSIZE]; 294 int i; 295 296 inetd_setproctitle(sep->se_service, s); 297 while ((i = read(s, buffer, sizeof(buffer))) > 0 && 298 write(s, buffer, i) > 0) 299 ; 300 exit(0); 301} 302 303/* 304 * RFC1413 Identification Protocol. Given a TCP port number pair, return a 305 * character string which identifies the owner of that connection on the 306 * server's system. Extended to allow for ~/.fakeid support and ~/.noident 307 * support. 308 */ 309 310/* ARGSUSED */ 311void 312iderror(lport, fport, s, er) /* Generic ident_stream error-sending func */ 313 int lport, fport, s, er; 314{ 315 char *p; 316 317 asprintf(&p, "%d , %d : ERROR : %s\r\n", lport, fport, 318 er == -1 ? "HIDDEN-USER" : er ? strerror(er) : "UNKNOWN-ERROR"); 319 if (p == NULL) { 320 syslog(LOG_ERR, "asprintf: %m"); 321 exit(EX_OSERR); 322 } 323 send(s, p, strlen(p), MSG_EOF); 324 free(p); 325 326 exit(0); 327} 328 329/* ARGSUSED */ 330void 331ident_stream(s, sep) /* Ident service (AKA "auth") */ 332 int s; 333 struct servtab *sep; 334{ 335 struct utsname un; 336 struct stat sb; 337 struct sockaddr_in sin[2]; 338#ifdef INET6 339 struct sockaddr_in6 sin6[2]; 340#endif 341 struct sockaddr_storage ss[2]; 342 struct ucred uc; 343 struct timeval tv = { 344 10, 345 0 346 }; 347 struct passwd *pw = NULL; 348 fd_set fdset; 349 char buf[BUFSIZE], *cp = NULL, *p, **av, *osname = NULL, garbage[7]; 350 char *fallback = NULL; 351 size_t len; 352 int c, fflag = 0, nflag = 0, rflag = 0, argc = 0, usedfallback = 0; 353 int gflag = 0, Rflag = 0, getcredfail = 0; 354 u_short lport, fport; 355 356 inetd_setproctitle(sep->se_service, s); 357 /* 358 * Reset getopt() since we are a fork() but not an exec() from 359 * a parent which used getopt() already. 360 */ 361 optind = 1; 362 optreset = 1; 363 /* 364 * Take the internal argument vector and count it out to make an 365 * argument count for getopt. This can be used for any internal 366 * service to read arguments and use getopt() easily. 367 */ 368 for (av = sep->se_argv; *av; av++) 369 argc++; 370 if (argc) { 371 int sec, usec; 372 size_t i; 373 u_int32_t random; 374 375 while ((c = getopt(argc, sep->se_argv, "d:fgno:rt:")) != -1) 376 switch (c) { 377 case 'd': 378 fallback = optarg; 379 break; 380 case 'f': 381 fflag = 1; 382 break; 383 case 'g': 384 gflag = 1; 385 random = 0; /* Shush, compiler. */ 386 /* 387 * The number of bits in "random" divided 388 * by the number of bits needed per iteration 389 * gives a more optimal way to reload the 390 * random number only when necessary. 391 * 392 * I'm using base-36, so I need at least 6 393 * bits; round it up to 8 bits to make it 394 * easier. 395 */ 396 for (i = 0; i < sizeof(garbage) - 1; i++) { 397 const char *const base36 = 398 "0123456789" 399 "abcdefghijklmnopqrstuvwxyz"; 400 if (i % (sizeof(random) * 8 / 8) == 0) 401 random = arc4random(); 402 garbage[i] = 403 base36[(random & 0xff) % 36]; 404 random >>= 8; 405 } 406 garbage[i] = '\0'; 407 break; 408 case 'n': 409 nflag = 1; 410 break; 411 case 'o': 412 osname = optarg; 413 break; 414 case 'R': 415 Rflag = 2; 416 break; 417 case 'r': 418 rflag = 1; 419 break; 420 case 't': 421 switch (sscanf(optarg, "%d.%d", &sec, &usec)) { 422 case 2: 423 tv.tv_usec = usec; 424 case 1: 425 tv.tv_sec = sec; 426 break; 427 default: 428 if (debug) 429 warnx("bad -t argument"); 430 break; 431 } 432 break; 433 default: 434 break; 435 } 436 } 437 if (osname == NULL) { 438 if (uname(&un) == -1) 439 iderror(0, 0, s, errno); 440 osname = un.sysname; 441 } 442 len = sizeof(ss[0]); 443 if (getsockname(s, (struct sockaddr *)&ss[0], &len) == -1) 444 iderror(0, 0, s, errno); 445 len = sizeof(ss[1]); 446 if (getpeername(s, (struct sockaddr *)&ss[1], &len) == -1) 447 iderror(0, 0, s, errno); 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 FD_ZERO(&fdset); 455 FD_SET(s, &fdset); 456 if (select(s + 1, &fdset, NULL, NULL, &tv) == -1) 457 iderror(0, 0, s, errno); 458 if (ioctl(s, FIONREAD, &len) == -1) 459 iderror(0, 0, s, errno); 460 if (len >= sizeof(buf)) 461 len = sizeof(buf) - 1; 462 len = read(s, buf, len); 463 if (len == -1) 464 iderror(0, 0, s, errno); 465 buf[len] = '\0'; 466 if (sscanf(buf, "%hu , %hu", &lport, &fport) != 2) 467 iderror(0, 0, s, 0); 468 if (gflag) { 469 cp = garbage; 470 goto printit; 471 } 472 473 /* 474 * If not "real" (-r), send a HIDDEN-USER error for everything. 475 * If -d is used to set a fallback username, this is used to 476 * override it, and the fallback is returned instead. 477 */ 478 if (!rflag) { 479 if (fallback == NULL) 480 iderror(lport, fport, s, -1); 481 else { 482 cp = fallback; 483 goto printit; 484 } 485 } 486 487 /* 488 * We take the input and construct an array of two sockaddr_ins 489 * which contain the local address information and foreign 490 * address information, respectively, used to look up the 491 * credentials for the socket (which are returned by the 492 * sysctl "net.inet.tcp.getcred" when we call it.) The 493 * arrays have been filled in above via get{peer,sock}name(), 494 * so right here we are only setting the ports. 495 */ 496 if (ss[0].ss_family != ss[1].ss_family) 497 iderror(lport, fport, s, errno); 498 len = sizeof(uc); 499 switch (ss[0].ss_family) { 500 case AF_INET: 501 sin[0] = *(struct sockaddr_in *)&ss[0]; 502 sin[0].sin_port = htons(lport); 503 sin[1] = *(struct sockaddr_in *)&ss[1]; 504 sin[1].sin_port = htons(fport); 505 if (sysctlbyname("net.inet.tcp.getcred", &uc, &len, sin, 506 sizeof(sin)) == -1) 507 getcredfail = 1; 508 break; 509#ifdef INET6 510 case AF_INET6: 511 sin6[0] = *(struct sockaddr_in6 *)&ss[0]; 512 sin6[0].sin6_port = htons(lport); 513 sin6[1] = *(struct sockaddr_in6 *)&ss[1]; 514 sin6[1].sin6_port = htons(fport); 515 if (sysctlbyname("net.inet6.tcp6.getcred", &uc, &len, sin6, 516 sizeof(sin6)) == -1) 517 getcredfail = 1; 518 break; 519#endif 520 default: /* should not reach here */ 521 getcredfail = 1; 522 break; 523 } 524 if (getcredfail != 0) { 525 if (fallback == NULL) /* Use a default, if asked to */ 526 iderror(lport, fport, s, errno); 527 usedfallback = 1; 528 } else { 529 /* Look up the pw to get the username */ 530 pw = getpwuid(uc.cr_uid); 531 } 532 if (pw == NULL && !usedfallback) /* No such user... */ 533 iderror(lport, fport, s, errno); 534 /* 535 * If enabled, we check for a file named ".noident" in the user's 536 * home directory. If found, we return HIDDEN-USER. 537 */ 538 if (nflag && !usedfallback) { 539 if (asprintf(&p, "%s/.noident", pw->pw_dir) == -1) 540 iderror(lport, fport, s, errno); 541 if (lstat(p, &sb) == 0) { 542 free(p); 543 iderror(lport, fport, s, -1); 544 } 545 free(p); 546 } 547 /* 548 * Here, if enabled, we read a user's ".fakeid" file in their 549 * home directory. It consists of a line containing the name 550 * they want. 551 */ 552 if (fflag && !usedfallback) { 553 FILE *fakeid = NULL; 554 555 if (asprintf(&p, "%s/.fakeid", pw->pw_dir) == -1) 556 iderror(lport, fport, s, errno); 557 /* 558 * Here we set ourself to effectively be the user, so we don't 559 * open any files we have no permission to open, especially 560 * symbolic links to sensitive root-owned files or devices. 561 */ 562 seteuid(pw->pw_uid); 563 setegid(pw->pw_gid); 564 /* 565 * If we were to lstat() here, it would do no good, since it 566 * would introduce a race condition and could be defeated. 567 * Therefore, we open the file we have permissions to open 568 * and if it's not a regular file, we close it and end up 569 * returning the user's real username. 570 */ 571 fakeid = fopen(p, "r"); 572 free(p); 573 if (fakeid != NULL && 574 fstat(fileno(fakeid), &sb) != -1 && S_ISREG(sb.st_mode)) { 575 buf[sizeof(buf) - 1] = '\0'; 576 if (fgets(buf, sizeof(buf), fakeid) == NULL) { 577 cp = pw->pw_name; 578 fclose(fakeid); 579 goto printit; 580 } 581 fclose(fakeid); 582 /* 583 * Usually, the file will have the desired identity 584 * in the form "identity\n", so we use strtok() to 585 * end the string (which fgets() doesn't do.) 586 */ 587 strtok(buf, "\r\n"); 588 /* User names of >16 characters are invalid */ 589 if (strlen(buf) > 16) 590 buf[16] = '\0'; 591 cp = buf; 592 /* Allow for beginning white space... */ 593 while (isspace(*cp)) 594 cp++; 595 /* ...and ending white space. */ 596 strtok(cp, " \t"); 597 /* 598 * If the name is a zero-length string or matches 599 * the name of another user, it's invalid, so 600 * we will return their real identity instead. 601 */ 602 603 if (!*cp || getpwnam(cp)) 604 cp = getpwuid(uc.cr_uid)->pw_name; 605 } else 606 cp = pw->pw_name; 607 } else if (!usedfallback) 608 cp = pw->pw_name; 609 else 610 cp = fallback; 611printit: 612 /* Finally, we make and send the reply. */ 613 if (asprintf(&p, "%d , %d : USERID : %s : %s\r\n", lport, fport, osname, 614 cp) == -1) { 615 syslog(LOG_ERR, "asprintf: %m"); 616 exit(EX_OSERR); 617 } 618 send(s, p, strlen(p), MSG_EOF); 619 free(p); 620 621 exit(0); 622} 623 624/* 625 * RFC738 Time Server. 626 * Return a machine readable date and time, in the form of the 627 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday 628 * returns the number of seconds since midnight, Jan 1, 1970, 629 * we must add 2208988800 seconds to this figure to make up for 630 * some seventy years Bell Labs was asleep. 631 */ 632 633unsigned long 634machtime() 635{ 636 struct timeval tv; 637 638 if (gettimeofday(&tv, (struct timezone *)NULL) < 0) { 639 if (debug) 640 warnx("unable to get time of day"); 641 return (0L); 642 } 643#define OFFSET ((u_long)25567 * 24*60*60) 644 return (htonl((long)(tv.tv_sec + OFFSET))); 645#undef OFFSET 646} 647 648/* ARGSUSED */ 649void 650machtime_dg(s, sep) 651 int s; 652 struct servtab *sep; 653{ 654 unsigned long result; 655 struct sockaddr_storage ss; 656 socklen_t size; 657 658 size = sizeof(ss); 659 if (recvfrom(s, (char *)&result, sizeof(result), 0, 660 (struct sockaddr *)&ss, &size) < 0) 661 return; 662 663 if (check_loop((struct sockaddr *)&ss, sep)) 664 return; 665 666 result = machtime(); 667 (void) sendto(s, (char *) &result, sizeof(result), 0, 668 (struct sockaddr *)&ss, size); 669} 670 671/* ARGSUSED */ 672void 673machtime_stream(s, sep) 674 int s; 675 struct servtab *sep; 676{ 677 unsigned long result; 678 679 result = machtime(); 680 (void) send(s, (char *) &result, sizeof(result), MSG_EOF); 681} 682 683/* 684 * RFC1078 TCP Port Service Multiplexer (TCPMUX). Service connections to 685 * services based on the service name sent. 686 * 687 * Based on TCPMUX.C by Mark K. Lottor November 1988 688 * sri-nic::ps:<mkl>tcpmux.c 689 */ 690 691#define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */ 692#define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1) 693 694static int /* # of characters upto \r,\n or \0 */ 695getline(fd, buf, len) 696 int fd; 697 char *buf; 698 int len; 699{ 700 int count = 0, n; 701 struct sigaction sa; 702 703 sa.sa_flags = 0; 704 sigemptyset(&sa.sa_mask); 705 sa.sa_handler = SIG_DFL; 706 sigaction(SIGALRM, &sa, (struct sigaction *)0); 707 do { 708 alarm(10); 709 n = read(fd, buf, len-count); 710 alarm(0); 711 if (n == 0) 712 return (count); 713 if (n < 0) 714 return (-1); 715 while (--n >= 0) { 716 if (*buf == '\r' || *buf == '\n' || *buf == '\0') 717 return (count); 718 count++; 719 buf++; 720 } 721 } while (count < len); 722 return (count); 723} 724 725struct servtab * 726tcpmux(s) 727 int s; 728{ 729 struct servtab *sep; 730 char service[MAX_SERV_LEN+1]; 731 int len; 732 733 /* Get requested service name */ 734 if ((len = getline(s, service, MAX_SERV_LEN)) < 0) { 735 strwrite(s, "-Error reading service name\r\n"); 736 return (NULL); 737 } 738 service[len] = '\0'; 739 740 if (debug) 741 warnx("tcpmux: someone wants %s", service); 742 743 /* 744 * Help is a required command, and lists available services, 745 * one per line. 746 */ 747 if (!strcasecmp(service, "help")) { 748 for (sep = servtab; sep; sep = sep->se_next) { 749 if (!ISMUX(sep)) 750 continue; 751 (void)write(s,sep->se_service,strlen(sep->se_service)); 752 strwrite(s, "\r\n"); 753 } 754 return (NULL); 755 } 756 757 /* Try matching a service in inetd.conf with the request */ 758 for (sep = servtab; sep; sep = sep->se_next) { 759 if (!ISMUX(sep)) 760 continue; 761 if (!strcasecmp(service, sep->se_service)) { 762 if (ISMUXPLUS(sep)) { 763 strwrite(s, "+Go\r\n"); 764 } 765 return (sep); 766 } 767 } 768 strwrite(s, "-Service not available\r\n"); 769 return (NULL); 770} 771