/* Timeout for resuming reading from sockets waiting for HW TX timestamp */
static double hwts_timeout = 0.001;
+/* Maximum number of saved messages for TX timestamp identification */
+static int max_tx_buffers = 0;
+
/* PTP event port (disabled by default) */
static int ptp_port = 0;
/* PTP domain number of NTP-over-PTP messages */
parse_int(p, &max_stratum, 0, INT_MAX);
} else if (!strcasecmp(command, "maxupdateskew")) {
parse_double(p, &max_update_skew);
+ } else if (!strcasecmp(command, "maxtxbuffers")) {
+ parse_int(p, &max_tx_buffers, 0, 1048576);
} else if (!strcasecmp(command, "minsamples")) {
parse_int(p, &min_samples, 0, INT_MAX);
} else if (!strcasecmp(command, "minsources")) {
/* ================================================== */
+int
+CNF_GetMaxTxBuffers(void)
+{
+ return max_tx_buffers;
+}
+
+/* ================================================== */
+
int
CNF_GetPtpPort(void)
{
requests), increasing the timeout to 0.01 or possibly even longer might help.
Note that the maximum timeout is limited by the NTP polling interval.
+[[maxtxbuffers]]*maxtxbuffers* _messages_::
+When *chronyd* gets a kernel or hardware transmit timestamp after sending an
+NTP message to a server, peer, or client (using interleaved mode), it needs the
+address and content of the message to be able to correctly assign the
+timestamp to the server, peer, or client. The timestamps are processed
+asynchronously. The kernel provides with each timestamp the data-link frame
+that was timestamped, but *chronyd* can extract the necessary data only from
+plain IPv4 and IPv6 packets in Ethernet frames, possibly including VLAN tags.
+If the NTP packets are transmitted by a non-Ethernet device, or they are
+encapsulated in another layer (e.g. a WireGuard tunnel), *chronyd* is not
+able to extract the data and use the kernel or hardware transmit timestamps,
+having to fall back to less accurate daemon timestamps.
++
+On Linux 6.13 and newer, *chronyd* supports an alternative method of processing
+kernel and hardware transmit timestamps, which works with any device that can
+provide kernel and/or hardware transmit timestamps. *chronyd* can save its
+transmitted messages with their addresses and ports in a ring buffer, each
+assigned an ID that the kernel will provide back with the timestamp. This
+transmit ID enables *chronyd* to assign the timestamp to the correct server,
+peer, or client.
++
+The directive specifies the maximum number of messages that *chronyd* is
+allowed to save in the ring buffer. The minimum value is 0 and the maximum
+value is 1048576. It needs about 1.5 KB of allocated memory per message.
+*chronyd* will log a warning if the number of messages is insufficient for the
+actual rate of transmit timestamping. The default value is 0 (disabled).
++
+Example:
+----
+maxtxbuffers 128
+----
+
[[keyfile]]*keyfile* _file_::
This directive is used to specify the location of the file containing symmetric
keys, which are shared between NTP servers and clients, or peers, in order to
#include "ntp_io.h"
#include "ntp_io_linux.h"
#include "ntp_sources.h"
+#include "ptp.h"
#include "sched.h"
#include "socket.h"
#include "sys_linux.h"
enabling the timestamping and sending a request */
static int dummy_rxts_socket;
+struct SavedTxMessage {
+ uint32_t tx_id;
+ int length;
+ NTP_Remote_Address remote_addr;
+ union {
+ NTP_Packet ntp_msg;
+ PTP_NtpMessage ptp_msg;
+ } message;
+};
+
+/* Ring buffer of transmitted messages to provide missing data needed for
+ processing of transmit timestamps */
+static ARR_Instance saved_tx_messages;
+static uint32_t last_saved_tx_id;
+
+/* Transmit IDs start at a non-zero value to detect missing kernel support */
+#define MIN_SAVED_TX_ID 0x1000
+
#define INVALID_SOCK_FD -3
/* ================================================== */
NIO_Linux_Initialise(void)
{
CNF_HwTsInterface *conf_iface;
+ int hwts, tx_buffers;
unsigned int i;
- int hwts;
interfaces = ARR_CreateInstance(sizeof (struct Interface));
#endif
}
+ saved_tx_messages = NULL;
+ last_saved_tx_id = 0;
+ tx_buffers = CNF_GetMaxTxBuffers();
+
+ if (tx_buffers > 0) {
+#if defined(HAVE_LINUX_TIMESTAMPING_OPT_ID) && defined(SCM_TS_OPT_ID)
+ /* Enable identification of packets looped back to the error queue using
+ a 32-bit integer and mapping of the IDs to saved messages to be able to
+ process TX timestamps of packets going out over tunnels or non-Ethernet
+ interfaces, where extract_udp_data() fails, or does not extract the
+ NTP message. If the SCM_TS_OPT_ID control message (setting the ID for
+ given packet) is not supported by the kernel, a zero ID will be received
+ and this functionality disabled in get_saved_tx_message(). */
+
+ if (check_timestamping_option(SOF_TIMESTAMPING_OPT_ID)) {
+ ts_tx_flags |= SOF_TIMESTAMPING_OPT_ID;
+
+ saved_tx_messages = ARR_CreateInstance(sizeof (struct SavedTxMessage));
+ ARR_SetSize(saved_tx_messages, tx_buffers);
+ memset(ARR_GetElements(saved_tx_messages), 0,
+ tx_buffers * sizeof (struct SavedTxMessage));
+ } else
+#endif
+ LOG(LOGS_WARN, "Transmit ID not supported");
+ }
+
/* Enable IP_PKTINFO in messages looped back to the error queue */
ts_flags |= SOF_TIMESTAMPING_OPT_CMSG;
struct Interface *iface;
unsigned int i;
+ if (saved_tx_messages)
+ ARR_DestroyInstance(saved_tx_messages);
+
if (dummy_rxts_socket != INVALID_SOCK_FD)
SCK_CloseSocket(dummy_rxts_socket);
local_ts->source = NTP_TS_KERNEL;
}
+/* ================================================== */
+
+static void
+save_tx_message(SCK_Message *message, NTP_Remote_Address *remote_addr)
+{
+ struct SavedTxMessage *saved_msg;
+
+ if (!saved_tx_messages || ARR_GetSize(saved_tx_messages) == 0 ||
+ message->length > sizeof (saved_msg->message))
+ return;
+
+ last_saved_tx_id++;
+ if (last_saved_tx_id < MIN_SAVED_TX_ID)
+ last_saved_tx_id = MIN_SAVED_TX_ID;
+
+ saved_msg = ARR_GetElement(saved_tx_messages,
+ last_saved_tx_id % ARR_GetSize(saved_tx_messages));
+ saved_msg->tx_id = last_saved_tx_id;
+ saved_msg->length = message->length;
+ saved_msg->remote_addr = *remote_addr;
+ memcpy(&saved_msg->message, message->data, message->length);
+
+ message->timestamp.tx_id = saved_msg->tx_id;
+}
+
+/* ================================================== */
+
+static int
+get_saved_tx_message(SCK_Message *message)
+{
+#ifdef HAVE_LINUX_TIMESTAMPING_OPT_ID
+ struct SavedTxMessage *saved_msg;
+
+ if (!saved_tx_messages)
+ return 0;
+
+ if (message->timestamp.tx_id < MIN_SAVED_TX_ID) {
+ LOG(LOGS_WARN, "Transmit ID not supported");
+
+ ARR_DestroyInstance(saved_tx_messages);
+ saved_tx_messages = NULL;
+ ts_tx_flags &= ~SOF_TIMESTAMPING_OPT_ID;
+ return 0;
+ }
+
+ saved_msg = ARR_GetElement(saved_tx_messages,
+ message->timestamp.tx_id % ARR_GetSize(saved_tx_messages));
+
+ if (message->timestamp.tx_id != saved_msg->tx_id) {
+ static int warned = 0;
+ if (!warned) {
+ LOG(LOGS_WARN, "maxtxbuffers too small");
+ warned = 1;
+ }
+ return 0;
+ }
+
+ message->data = &saved_msg->message;
+ message->length = saved_msg->length;
+ message->remote_addr.ip = saved_msg->remote_addr;
+
+ return 1;
+#else
+ return 0;
+#endif
+}
+
/* ================================================== */
/* Extract UDP data from a layer 2 message. Supported is Ethernet
with optional VLAN tags. */
currently doesn't seem to be a better way to get them both. */
l2_length = message->length;
- if (extract_udp_data(message)) {
+ if (get_saved_tx_message(message)) {
+ DEBUG_LOG("Found saved message for %s fd=%d len=%d",
+ UTI_IPSockAddrToString(&message->remote_addr.ip),
+ local_addr->sock_fd, message->length);
+ } else if (extract_udp_data(message)) {
DEBUG_LOG("Extracted message for %s fd=%d len=%d",
UTI_IPSockAddrToString(&message->remote_addr.ip),
local_addr->sock_fd, message->length);
/* ================================================== */
void
-NIO_Linux_RequestTxTimestamp(SCK_Message *message, int sock_fd)
+NIO_Linux_RequestTxTimestamp(SCK_Message *message, int sock_fd,
+ NTP_Remote_Address *remote_addr)
{
if (!ts_flags)
return;
+ save_tx_message(message, remote_addr);
+
/* Check if TX timestamping is disabled on this socket */
if (permanent_ts_options || !NIO_IsServerSocket(sock_fd))
return;
projects / thirdparty / chrony.git / commitdiff
