diff options
| -rw-r--r-- | usr.sbin/rdate/ntp.c | 304 |
1 files changed, 135 insertions, 169 deletions
diff --git a/usr.sbin/rdate/ntp.c b/usr.sbin/rdate/ntp.c index 9479f7c1548..193f864d69b 100644 --- a/usr.sbin/rdate/ntp.c +++ b/usr.sbin/rdate/ntp.c @@ -1,4 +1,4 @@ -/* $OpenBSD: ntp.c,v 1.20 2004/06/05 19:18:56 alexander Exp $ */ +/* $OpenBSD: ntp.c,v 1.21 2004/06/09 07:15:56 alexander Exp $ */ /* * Copyright (c) 1996, 1997 by N.M. Maclaren. All rights reserved. @@ -64,11 +64,11 @@ #define NTP_MODE_CLIENT 3 /* NTP client mode */ #define NTP_MODE_SERVER 4 /* NTP server mode */ -#define NTP_VERSION 3 /* The current version */ +#define NTP_VERSION 4 /* The current version */ #define NTP_VERSION_MIN 1 /* The minum valid version */ #define NTP_VERSION_MAX 4 /* The maximum valid version */ #define NTP_STRATUM_MIN 1 /* The minum valid stratum */ -#define NTP_STRATUM_MAX 15 /* The maximum valid stratum */ +#define NTP_STRATUM_MAX 14 /* The maximum valid stratum */ #define NTP_INSANITY 3600.0 /* Errors beyond this are hopeless */ #define NTP_PACKET_MIN 48 /* Without authentication */ @@ -92,33 +92,32 @@ #define MILLION_D 1.0e6 /* Must be equal to MILLION_L */ struct ntp_data { - u_char status; - u_char version; - u_char mode; - u_char stratum; - u_char polling; - u_char precision; - double dispersion; - double reference; - double originate; - double receive; - double transmit; - double current; - - u_int64_t xmitck; - u_int64_t recvck; + u_char status; + u_char version; + u_char mode; + u_char stratum; + double receive; + double transmit; + double current; + u_int64_t recvck; + + /* Local State */ + double originate; + u_int64_t xmitck; }; void ntp_client(const char *, int, struct timeval *, struct timeval *, int); int sync_ntp(int, const struct sockaddr *, double *, double *); -void make_packet(struct ntp_data *); -int write_packet(int, const struct sockaddr *, struct ntp_data *); -int read_packet(int, struct ntp_data *, double *, double *, double *); -void pack_ntp(u_char *, int, struct ntp_data *); -void unpack_ntp(struct ntp_data *, u_char *, int); +int write_packet(int, struct ntp_data *); +int read_packet(int, struct ntp_data *, double *, double *); +void unpack_ntp(struct ntp_data *, u_char *); double current_time(double); void create_timeval(double, struct timeval *, struct timeval *); +#if DEBUG +void print_packet(const struct ntp_data *); +#endif + int corrleaps; void @@ -127,7 +126,7 @@ ntp_client(const char *hostname, int family, struct timeval *new, { struct addrinfo hints, *res0, *res; double offset, error; - int packets = 0, s, ierror; + int accept = 0, ret, s, ierror; memset(&hints, 0, sizeof(hints)); hints.ai_family = family; @@ -148,8 +147,8 @@ ntp_client(const char *hostname, int family, struct timeval *new, if (s < 0) continue; - packets = sync_ntp(s, res->ai_addr, &offset, &error); - if (packets == 0) { + ret = sync_ntp(s, res->ai_addr, &offset, &error); + if (ret < 0) { #ifdef DEBUG fprintf(stderr, "try the next address\n"); #endif @@ -157,10 +156,8 @@ ntp_client(const char *hostname, int family, struct timeval *new, s = -1; continue; } - if (error > NTP_INSANITY) { - /* should we try the next address instead? */ - errx(1, "Unable to get a reasonable time estimate"); - } + + accept++; break; } freeaddrinfo(res0); @@ -169,6 +166,10 @@ ntp_client(const char *hostname, int family, struct timeval *new, fprintf(stderr,"Correction: %.6f +/- %.6f\n", offset,error); #endif + if (accept < 1) { + errx(1, "Unable to get a reasonable time estimate"); + } + create_timeval(offset, new, adjust); } @@ -176,35 +177,52 @@ int sync_ntp(int fd, const struct sockaddr *peer, double *offset, double *error) { int attempts = 0, accepts = 0, rejects = 0; - int delay = MAX_DELAY; + int delay = MAX_DELAY, ret; double deadline; double a, b, x, y; double minerr = 0.1; /* Maximum ignorable variation */ - double dispersion = 0.0; /* The source dispersion in seconds */ struct ntp_data data; deadline = current_time(JAN_1970) + delay; *offset = 0.0; *error = NTP_INSANITY; + if (connect(fd, peer, SA_LEN(peer)) < 0) { + warn("Failed to connect to server"); + return -1; + } + while (accepts < MAX_QUERIES && attempts < 2 * MAX_QUERIES) { - if (current_time(JAN_1970) > deadline) - errx(1, "Not enough valid responses received in time"); + memset(&data, 0, sizeof(data)); - make_packet(&data); - write_packet(fd, peer, &data); + if (current_time(JAN_1970) > deadline) { + warnx("Not enough valid responses received in time"); + return -1; + } - if (read_packet(fd, &data, &x, &y, &dispersion)) { - if (++rejects > MAX_QUERIES) - errx(1, "Too many bad or lost packets"); - else - continue; + if (write_packet(fd, &data) < 0) + return -1; + + ret = read_packet(fd, &data, &x, &y); + + if (ret < 0) + return -1; + else if (ret > 0) { +#ifdef DEBUG + print_packet(&data); +#endif + + if (++rejects > MAX_QUERIES) { + warnx("Too many bad or lost packets"); + return -1; + } else + continue; } else ++accepts; #ifdef DEBUG - fprintf(stderr,"Offset: %.6f +/- %.6f disp=%.6f\n", - x, y, dispersion); + fprintf(stderr,"Offset: %.6f +/- %.6f\n", + x, y); #endif if ((a = x - *offset) < 0.0) @@ -221,8 +239,10 @@ sync_ntp(int fd, const struct sockaddr *peer, double *offset, double *error) fprintf(stderr,"Best: %.6f +/- %.6f\n", *offset, *error); #endif - if (a > b) - errx(1, "Inconsistent times received from NTP server"); + if (a > b) { + warnx("Inconsistent times received from NTP server"); + return -1; + } if (*error <= minerr) break; @@ -231,21 +251,18 @@ sync_ntp(int fd, const struct sockaddr *peer, double *offset, double *error) return accepts; } -/* Create an outgoing NTP packet */ -void -make_packet(struct ntp_data *data) +/* Send out NTP packet. */ +int +write_packet(int fd, struct ntp_data *data) { - data->status = STATUS_NOWARNING; - data->version = NTP_VERSION; - data->mode = NTP_MODE_CLIENT; - data->stratum = 0; - data->polling = 0; - data->precision = 0; - data->reference = data->dispersion = 0.0; - data->receive = 0.0; - data->current = data->transmit = current_time(JAN_1970); - data->originate = data->transmit; + u_char packet[NTP_PACKET_MIN]; + ssize_t length; + + memset(packet, 0, sizeof(packet)); + + packet[0] = (NTP_VERSION << 3) | (NTP_MODE_CLIENT); + data->xmitck = (u_int64_t)arc4random() << 32 | arc4random(); /* * Send out a random 64-bit number as our transmit time. The NTP @@ -258,23 +275,20 @@ make_packet(struct ntp_data *data) * getting spoofed by an attacker that can't capture our traffic * but can spoof packets from the NTP server we're communicating with. * + * No endian concerns here. Since we're running as a strict + * unicast client, we don't have to worry about anyone else finding + * the transmit field intelligible. */ - data->xmitck = ((u_int64_t)arc4random() << 32) | arc4random(); - data->recvck = 0; -} + *(u_int64_t *)(packet + NTP_TRANSMIT) = data->xmitck; -int -write_packet(int fd, const struct sockaddr *peer, struct ntp_data *data) -{ - u_char transmit[NTP_PACKET_MIN]; - ssize_t length; + data->originate = current_time(JAN_1970); - pack_ntp(transmit, NTP_PACKET_MIN, data); - length = sendto(fd, transmit, NTP_PACKET_MIN, 0, peer, SA_LEN(peer)); - if (length == -1) { - warnx("Unable to send NTP packet to server"); - return 1; + length = write(fd, packet, sizeof(packet)); + + if (length != sizeof(packet)) { + warn("Unable to send NTP packet to server"); + return -1; } return 0; @@ -287,14 +301,13 @@ write_packet(int fd, const struct sockaddr *peer, struct ntp_data *data) * if it fails. */ int -read_packet(int fd, struct ntp_data *data, double *off, double *error, - double *dispersion) +read_packet(int fd, struct ntp_data *data, double *off, double *error) { - u_char receive[NTP_PACKET_MAX+1]; - double delay, x, y; + u_char receive[NTP_PACKET_MAX]; + struct timeval tv; + double x, y; int length, r; fd_set *rfds; - struct timeval tv; rfds = (fd_set *)calloc(howmany(fd + 1, NFDBITS), sizeof(fd_mask)); if (!rfds) { @@ -309,22 +322,31 @@ retry: tv.tv_usec = 1000000 * MAX_DELAY / MAX_QUERIES; r = select(fd + 1, rfds, NULL, NULL, &tv); - if (r < 1 || !FD_ISSET(fd, rfds)) { - if (r < 0) { - if (errno == EINTR) - goto retry; - else - warnx("select() failed"); - } + + if (r < 0) { + if (errno == EINTR) + goto retry; + else + warn("select"); + free(rfds); + + return r; + } + + if (r != 1 || !FD_ISSET(fd, rfds)) { + free(rfds); + return 1; } + free(rfds); - length = recvfrom(fd, receive, NTP_PACKET_MAX + 1, 0, NULL, 0); + length = read(fd, receive, NTP_PACKET_MAX); + if (length < 0) { - warnx("Unable to receive NTP packet from server"); - return 1; + warn("Unable to receive NTP packet from server"); + return -1; } if (length < NTP_PACKET_MIN || length > NTP_PACKET_MAX) { @@ -332,16 +354,16 @@ retry: return 1; } - unpack_ntp(data, receive, length); + unpack_ntp(data, receive); if (data->recvck != data->xmitck) { warnx("Invalid cookie received, packet rejected"); return 1; } - if (data->version < NTP_VERSION_MIN || - data->version > NTP_VERSION_MAX) { - warnx("Invalid NTP version, packet rejected"); + if (data->version != NTP_VERSION) { + warnx("Received different NTP version than sent," + "packet rejected"); return 1; } @@ -350,76 +372,34 @@ retry: return 1; } + if (data->stratum < NTP_STRATUM_MIN || + data->stratum > NTP_STRATUM_MAX) { + warnx("Invalid stratum received, packet rejected"); + return 1; + } + if (data->status == STATUS_ALARM) { warnx("Server clock not synchronized, packet rejected"); return 1; } - /* - * Note that the conventions are very poorly defined in the NTP - * protocol, so we have to guess. Any full NTP server perpetrating - * completely unsynchronised packets is an abomination, anyway, so - * reject it. - */ - delay = data->transmit - data->receive; - - if (data->reference == 0.0 || - data->transmit == 0.0 || - data->receive == 0.0 || - (data->reference != 0.0 && data->receive < data->reference) || - delay < 0.0 || - delay > NTP_INSANITY || - data->dispersion > NTP_INSANITY) { - warnx("Incomprehensible NTP packet rejected"); + if (data->transmit == 0.0) { + warnx("Server clock invalid, packet rejected"); return 1; } - if (*dispersion < data->dispersion) - *dispersion = data->dispersion; - x = data->receive - data->originate; - y = (data->transmit == 0.0 ? 0.0 : data->transmit-data->current); - *off = 0.5*(x+y); - *error = x-y; - x = data->current - data->originate; - if (0.5*x > *error) - *error = 0.5*x; - - return 0; -} + y = data->transmit - data->current; -/* - * Pack the essential data into an NTP packet, bypassing struct layout - * and endian problems. Note that it ignores fields irrelevant to - * SNTP. - */ -void -pack_ntp(u_char *packet, int length, struct ntp_data *data) -{ - int i, k; - double d; + *off = (x + y) / 2; + *error = x - y; - memset(packet,0, (size_t)length); + x = (data->current - data->originate) / 2; - packet[0] = (data->status<<6)|(data->version<<3)|data->mode; - packet[1] = data->stratum; - packet[2] = data->polling; - packet[3] = data->precision; + if (x > *error) + *error = x; - d = data->receive/NTP_SCALE; - for (i = 0; i < 8; ++i) { - if ((k = (int)(d *= 256.0)) >= 256) k = 255; - packet[NTP_RECEIVE+i] = k; - d -= k; - } - - /* - * No endian concerns here. Since we're running as a strict - * unicast client, we don't have to worry about anyone else finding - * this field intelligible. - */ - - *(u_int64_t *)(packet + NTP_TRANSMIT) = data->xmitck; + return 0; } /* @@ -428,7 +408,7 @@ pack_ntp(u_char *packet, int length, struct ntp_data *data) * to SNTP. */ void -unpack_ntp(struct ntp_data *data, u_char *packet, int length) +unpack_ntp(struct ntp_data *data, u_char *packet) { int i; double d; @@ -436,19 +416,9 @@ unpack_ntp(struct ntp_data *data, u_char *packet, int length) data->current = current_time(JAN_1970); data->status = (packet[0] >> 6); - data->version = (packet[0] >> 3)&0x07; - data->mode = packet[0]&0x07; + data->version = (packet[0] >> 3) & 0x07; + data->mode = packet[0] & 0x07; data->stratum = packet[1]; - data->polling = packet[2]; - data->precision = packet[3]; - - for (i = 0, d = 0.0; i < 4; ++i) - d = 256.0*d+packet[NTP_DISP_FIELD+i]; - data->dispersion = d/65536.0; - - for (i = 0, d = 0.0; i < 8; ++i) - d = 256.0*d+packet[NTP_REFERENCE+i]; - data->reference = d/NTP_SCALE; for (i = 0, d = 0.0; i < 8; ++i) d = 256.0*d+packet[NTP_RECEIVE+i]; @@ -458,7 +428,7 @@ unpack_ntp(struct ntp_data *data, u_char *packet, int length) d = 256.0*d+packet[NTP_TRANSMIT+i]; data->transmit = d/NTP_SCALE; - /* See unpack_ntp for why there is no byte-order change. */ + /* See write_packet for why this isn't an endian problem. */ data->recvck = *(u_int64_t *)(packet + NTP_ORIGINATE); } @@ -526,14 +496,10 @@ print_packet(const struct ntp_data *data) printf("version: %u\n", data->version); printf("mode: %u\n", data->mode); printf("stratum: %u\n", data->stratum); - printf("polling: %u\n", data->polling); - printf("precision: %u\n", data->precision); - printf("dispersion: %e\n", data->dispersion); - printf("reference: %e\n", data->reference); - printf("originate: %e\n", data->originate); - printf("receive: %e\n", data->receive); - printf("transmit: %e\n", data->transmit); - printf("current: %e\n", data->current); + printf("originate: %f\n", data->originate); + printf("receive: %f\n", data->receive); + printf("transmit: %f\n", data->transmit); + printf("current: %f\n", data->current); printf("xmitck: 0x%0llX\n", data->xmitck); printf("recvck: 0x%0llX\n", data->recvck); }; |