From cea6a95c467dfcc1cc82ef3df0f76fccb85f5f04 Mon Sep 17 00:00:00 2001 From: Rob Landley Date: Tue, 5 Feb 2019 08:40:34 -0600 Subject: Promote sntp to net. --- toys/pending/sntp.c | 269 ---------------------------------------------------- 1 file changed, 269 deletions(-) delete mode 100644 toys/pending/sntp.c (limited to 'toys/pending') diff --git a/toys/pending/sntp.c b/toys/pending/sntp.c deleted file mode 100644 index f1415332..00000000 --- a/toys/pending/sntp.c +++ /dev/null @@ -1,269 +0,0 @@ -/* sntp.c - sntp client and server - * - * Copyright 2019 Rob Landley - * - * See https://www.ietf.org/rfc/rfc4330.txt - - modes: oneshot display, oneshot set, persist, serve, multi - -USE_SNTP(NEWTOY(sntp, "m:Sp:asdDqr#<4>17=10[!as]", TOYFLAG_USR|TOYFLAG_BIN)) - -config SNTP - bool "sntp" - default n - help - usage: sntp [-saSdDqm] [-r SHIFT] [-m ADDRESS] [-p PORT] [SERVER] - - Simple Network Time Protocol client. Query SERVER and display time. - - -p Use PORT (default 123) - -s Set system clock suddenly - -a Adjust system clock gradually - -S Serve time instead of querying (bind to SERVER address if specified) - -m Wait for updates from multicast ADDRESS (RFC 4330 says use 224.0.1.1) - -d Daemonize (run in background re-querying ) - -D Daemonize but stay in foreground: re-query time every 1000 seconds - -r Retry shift (every 1<= 0) { - struct pollfd pfd; - - pfd.fd = fd; - pfd.events = POLLIN; - if (!xpoll(&pfd, 1, timeout)) return 0; - } - - len = recvfrom(fd, buf, len, 0, (void *)sa, &sl); - if (len<0) perror_exit("recvfrom"); - - return len; -} - -// Adjust timespec by nanosecond offset -static void nanomove(struct timespec *ts, long long offset) -{ - long long nano = ts->tv_nsec + offset, secs = nano/1000000000; - - ts->tv_sec += secs; - nano %= 1000000000; - if (nano<0) { - ts->tv_sec--; - nano += 1000000000; - } - ts->tv_nsec = nano; -} - -// Get time and return ntptime (saving timespec in pointer if not null) -// NTP time is high 32 bits = seconds since 1970 (blame RFC 868), low 32 bits -// fraction of a second. -// diff is how far off we think our clock is from reality (in nanoseconds) -static unsigned long long lunchtime(struct timespec *television, long long diff) -{ - struct timespec tv; - - clock_gettime(CLOCK_REALTIME, &tv); - if (diff) nanomove(&tv, diff); - - if (television) *television = tv; - - // Unix time is 1970 but RFCs 868 and 958 said 1900 so add seconds 1900->1970 - // If they'd done a 34/30 bit split the Y2036 problem would be centuries - // from now and still give us nanosecond accuracy, but no... - return ((tv.tv_sec+SEVENTIES)<<32)+(((long long)tv.tv_nsec)<<32)/1000000000; -} - -// convert ntptime back to struct timespec. -static void doublyso(unsigned long long now, struct timespec *tv) -{ - // Y2036 fixup: if time wrapped, it's in the future - tv->tv_sec = (now>>32) + (1LL<<32)*!(now&(1LL<<63)); - tv->tv_sec -= SEVENTIES; // Force signed math for Y2038 fixup - tv->tv_nsec = ((now&0xFFFFFFFF)*1000000000)>>32; -} - -// return difference between two timespecs in nanosecs -static long long nanodiff(struct timespec *old, struct timespec *new) -{ - return (new->tv_sec - old->tv_sec)*1000000000LL+(new->tv_nsec - old->tv_nsec); -} - -void sntp_main(void) -{ - struct timespec tv, tv2; - unsigned long long *pktime = (void *)toybuf, now, then, before = before; - long long diff = 0; - struct addrinfo *ai; - union socksaddr sa; - int fd, tries = 0; - - if (!(FLAG(S)||FLAG(m)) && !*toys.optargs) - error_exit("Need -Sm or SERVER address"); - - // Lookup address and open server or client UDP socket - if (!TT.p || !*TT.p) TT.p = "123"; - ai = xgetaddrinfo(*toys.optargs, TT.p, AF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, - AI_PASSIVE*!*toys.optargs); - - if (FLAG(d) && daemon(0, 0)) perror_exit("daemonize"); - - // Act as server if necessary - if (FLAG(S)|FLAG(m)) { - fd = xbind(ai); - if (TT.m) { - struct ip_mreq group; - - // subscribe to multicast group - memset(&group, 0, sizeof(group)); - group.imr_multiaddr.s_addr = inet_addr(TT.m); - xsetsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &group, sizeof(group)); - } - } else fd = xsocket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP); - - // -Sm = loop waiting for input - // -Dd = loop polling time and waiting until next poll period - // Otherwise poll up to 3 times to get 2 responses, then exit - - // loop sending/receiving packets - for (;;) { - now = millitime(); - - // Figure out if we're in server and multicast modes don't poll - if (FLAG(m) || FLAG(S)) then = -1; - - // daemon and oneshot modes send a packet each time through outer loop - else { - then = now + 3000; - if (FLAG(d) || FLAG(D)) then = now + (1<ai_addr); - } - - // Loop receiving packets until it's time to send the next one. - for (;;) { - int strike; - - // Wait to receive a packet - - if (then>0 && then<(now = millitime())) break;; - strike = xrecvwait(fd, toybuf, sizeof(toybuf), &sa, then-now); - if (strike<1) { - if (!(FLAG(S)||FLAG(m)||FLAG(D)||FLAG(d)) && ++tries == 3) - error_exit("no reply from %s", *toys.optargs); - break; - } - if (strike<48) continue; - - // Validate packet - if (!FLAG(S) || FLAG(m)) { - char buf[128]; - int mode = 7&*toybuf; - - // Is source address what we expect? - xstrncpy(buf, ntop(ai->ai_addr), 128); - strike = strcmp(buf, ntop((void *)&sa)); - // Does this reply's originate timestamp match the packet we sent? - if (!FLAG(S) && !FLAG(m) && before != SWAP_BE64(pktime[3])) continue; - // Ignore packets from wrong address or with wrong mode - if (strike && !FLAG(S)) continue; - if (!((FLAG(m) && mode==5) || (FLAG(S) && mode==3) || - (!FLAG(m) && !FLAG(S) && mode==4))) continue; - } - - // If received a -S request packet, send server packet - if (strike) { - char *buf = toybuf+48; - - *buf = 0x24; // LI 0 VN 4 mode 4. - buf[1] = 3; // stratum 3 - buf[2] = 10; // recommended retry every 1<<10=1024 seconds - buf[3] = 250; // precision -6, minimum allowed - strcpy(buf+12, "LOCL"); - pktime[6+3] = pktime[5]; // send back reference time they sent us - // everything else is current time - pktime[6+2] = pktime[6+4] = pktime[6+5] = SWAP_BE64(lunchtime(0, 0)); - xsendto(fd, buf, 48, (void *)&sa); - - // Got a time packet from a recognized server - } else { - int unset = !diff; - - // First packet: figure out how far off our clock is from what server - // said and try again. Don't set clock, just record offset to use - // generating second reuest. (We know this time is in the past - // because transmission took time, but it's a start. And if time is - // miraculously exact, don't loop.) - - lunchtime(&tv2, diff); - diff = nanodiff(&tv, &tv2); - if (unset && diff) break; - - // Second packet: determine midpoint of packet transit time according - // to local clock, assuming each direction took same time so midpoint - // is time server reported. The first television was the adjusted time - // we sent the packet at, tv2 is what server replied, so now diff - // is round trip time. - - // What time did the server say and how far off are we? - nanomove(&tv, diff/2); - doublyso(SWAP_BE64(pktime[5]), &tv2); - diff = nanodiff(&tv, &tv2); - - if (FLAG(s)) { - // Do read/adjust/set to lose as little time as possible. - clock_gettime(CLOCK_REALTIME, &tv2); - nanomove(&tv2, diff); - if (clock_settime(CLOCK_REALTIME, &tv2)) - perror_exit("clock_settime"); - } else if (FLAG(a)) { - struct timeval why; - - // call adjtime() to move the clock gradually, copying nanoseconds - // into gratuitous microseconds structure for sad historical reasons - memset(&tv2, 0, sizeof(tv2)); - nanomove(&tv2, diff); - why.tv_sec = tv2.tv_sec; - why.tv_usec = tv2.tv_nsec/1000; - if (adjtime(&why, 0)) perror_exit("adjtime"); - } - - // Display the time and offset - if (!FLAG(q)) { - format_iso_time(toybuf, sizeof(toybuf)-1, &tv2); - printf("%s offset %c%lld.%09lld secs\n", toybuf, (diff<0) ? '-' : '+', - llabs(diff/1000000000), llabs(diff%1000000000)); - } - - // If we're not in daemon mode, we're done. (Can't get here for -S.) - if (!FLAG(d) && !FLAG(D)) return; - } - } - } -} -- cgit v1.2.3