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ntp: prepare for non-authentication extension fields

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Add a new variable to the packet info structure with flags for extension
fields included in received packets and add a new parameter to
transmit_packet() to add the fields to transmitted packets.
This commit is contained in:
Miroslav Lichvar 2021-11-08 16:35:47 +01:00
parent 36356ef033
commit 125d7a5c32
2 changed files with 36 additions and 6 deletions
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1
ntp.h
View file

@ -137,6 +137,7 @@ typedef struct {
NTP_Mode mode;
int ext_fields;
int ext_field_flags;
struct {
NTP_AuthMode mode;

41
ntp_core.c
View file

@ -132,6 +132,8 @@ struct NCR_Instance_Record {
double offset_correction; /* Correction applied to measured offset
(e.g. for asymmetry in network delay) */
int ext_field_flags; /* Enabled extension fields */
NAU_Instance auth; /* Authentication */
/* Count of transmitted packets since last valid response */
@ -567,6 +569,7 @@ NCR_CreateInstance(NTP_Remote_Address *remote_addr, NTP_Source_Type type,
result->auto_offline = params->auto_offline;
result->copy = params->copy && result->mode == MODE_CLIENT;
result->poll_target = params->poll_target;
result->ext_field_flags = 0;
if (params->nts) {
IPSockAddr nts_address;
@ -585,7 +588,10 @@ NCR_CreateInstance(NTP_Remote_Address *remote_addr, NTP_Source_Type type,
result->auth = NAU_CreateNoneInstance();
}
result->version = NAU_GetSuggestedNtpVersion(result->auth);
if (result->ext_field_flags)
result->version = NTP_VERSION;
else
result->version = NAU_GetSuggestedNtpVersion(result->auth);
if (params->version)
result->version = CLAMP(NTP_MIN_COMPAT_VERSION, params->version, NTP_VERSION);
@ -925,6 +931,7 @@ transmit_packet(NTP_Mode my_mode, /* The mode this machine wants to be */
int my_poll, /* The log2 of the local poll interval */
int version, /* The NTP version to be set in the packet */
uint32_t kod, /* KoD code - 0 disabled */
int ext_field_flags, /* Extension fields to be included in the packet */
NAU_Instance auth, /* The authentication to be used for the packet */
NTP_int64 *remote_ntp_rx, /* The receive timestamp from received packet */
NTP_int64 *remote_ntp_tx, /* The transmit timestamp from received packet */
@ -1062,6 +1069,9 @@ transmit_packet(NTP_Mode my_mode, /* The mode this machine wants to be */
if (!parse_packet(&message, NTP_HEADER_LENGTH, &info))
return 0;
if (ext_field_flags) {
}
do {
/* Prepare random bits which will be added to the transmit timestamp */
UTI_GetNtp64Fuzz(&ts_fuzz, precision);
@ -1240,7 +1250,7 @@ transmit_timeout(void *arg)
/* Send the request (which may also be a response in the symmetric mode) */
sent = transmit_packet(inst->mode, interleaved, inst->local_poll, inst->version, 0,
inst->auth,
inst->ext_field_flags, inst->auth,
initial ? NULL : &inst->remote_ntp_rx,
initial ? &inst->init_remote_ntp_tx : &inst->remote_ntp_tx,
initial ? &inst->init_local_rx : &inst->local_rx,
@ -1313,8 +1323,9 @@ is_zero_data(unsigned char *data, int length)
static int
parse_packet(NTP_Packet *packet, int length, NTP_PacketInfo *info)
{
int parsed, remainder, ef_length, ef_type;
int parsed, remainder, ef_length, ef_type, ef_body_length;
unsigned char *data;
void *ef_body;
if (length < NTP_HEADER_LENGTH || length % 4U != 0) {
DEBUG_LOG("NTP packet has invalid length %d", length);
@ -1325,6 +1336,7 @@ parse_packet(NTP_Packet *packet, int length, NTP_PacketInfo *info)
info->version = NTP_LVM_TO_VERSION(packet->lvm);
info->mode = NTP_LVM_TO_MODE(packet->lvm);
info->ext_fields = 0;
info->ext_field_flags = 0;
info->auth.mode = NTP_AUTH_NONE;
if (info->version < NTP_MIN_COMPAT_VERSION || info->version > NTP_MAX_COMPAT_VERSION) {
@ -1379,7 +1391,8 @@ parse_packet(NTP_Packet *packet, int length, NTP_PacketInfo *info)
break;
/* Check if this is a valid NTPv4 extension field and skip it */
if (!NEF_ParseField(packet, info->length, parsed, &ef_length, &ef_type, NULL, NULL)) {
if (!NEF_ParseField(packet, info->length, parsed,
&ef_length, &ef_type, &ef_body, &ef_body_length)) {
DEBUG_LOG("Invalid format");
return 0;
}
@ -1597,6 +1610,10 @@ process_response(NCR_Instance inst, NTP_Local_Address *local_addr,
/* Kiss-o'-Death codes */
int kod_rate;
/* Extension fields */
int parsed, ef_length, ef_type, ef_body_length;
void *ef_body;
NTP_Local_Timestamp local_receive, local_transmit;
double remote_interval, local_interval, response_time;
double delay_time, precision;
@ -1606,6 +1623,18 @@ process_response(NCR_Instance inst, NTP_Local_Address *local_addr,
stats = SRC_GetSourcestats(inst->source);
/* Find requested non-authentication extension fields */
if (inst->ext_field_flags & info->ext_field_flags) {
for (parsed = NTP_HEADER_LENGTH; parsed < info->length; parsed += ef_length) {
if (!NEF_ParseField(message, info->length, parsed,
&ef_length, &ef_type, &ef_body, &ef_body_length))
break;
switch (ef_type) {
}
}
}
pkt_leap = NTP_LVM_TO_LEAP(message->lvm);
pkt_version = NTP_LVM_TO_VERSION(message->lvm);
pkt_refid = ntohl(message->reference_id);
@ -2253,7 +2282,7 @@ NCR_ProcessRxUnknown(NTP_Remote_Address *remote_addr, NTP_Local_Address *local_a
version = info.version;
/* Send a reply */
if (!transmit_packet(my_mode, interleaved, poll, version, kod, NULL,
if (!transmit_packet(my_mode, interleaved, poll, version, kod, info.ext_field_flags, NULL,
&message->receive_ts, &message->transmit_ts,
rx_ts, tx_ts, local_ntp_rx, NULL, remote_addr, local_addr,
message, &info))
@ -2727,7 +2756,7 @@ broadcast_timeout(void *arg)
UTI_ZeroNtp64(&orig_ts);
zero_local_timestamp(&recv_ts);
transmit_packet(MODE_BROADCAST, 0, poll, NTP_VERSION, 0, destination->auth,
transmit_packet(MODE_BROADCAST, 0, poll, NTP_VERSION, 0, 0, destination->auth,
&orig_ts, &orig_ts, &recv_ts, NULL, NULL, NULL,
&destination->addr, &destination->local_addr, NULL, NULL);