unix: add PTP IOCTLs on Linux

The IOCTLs are used for interacting with PTP-specific functions of
NIC and time card drivers.

Description:
https://netdevconf.info/0x18/docs/netdev-0x18-paper39-talk-slides/netdev-intro-ptp-api.pdf

unix/ioctl_linux.go

@@ -99,6 +99,61 @@ func IoctlSetHwTstamp(fd int, ifname string, cfg *HwTstampConfig) error {
 	return ioctlIfreqData(fd, SIOCSHWTSTAMP, &ifrd)
 }
 
+// FdToClockID derives the clock ID from the file descriptor number
+// - see clock_gettime(3), FD_TO_CLOCKID macros. The resulting ID is
+// suitable for system calls like ClockGettime.
+func FdToClockID(fd int) int32 { return int32((int(^fd) << 3) | 3) }
+
+// IoctlPtpClockGetcaps returns the description of a given PTP device.
+func IoctlPtpClockGetcaps(fd int) (*PtpClockCaps, error) {
+	var value PtpClockCaps
+	err := ioctlPtr(fd, PTP_CLOCK_GETCAPS2, unsafe.Pointer(&value))
+	return &value, err
+}
+
+// IoctlPtpSysOffsetPrecise returns a description of the clock
+// offset compared to the system clock.
+func IoctlPtpSysOffsetPrecise(fd int) (*PtpSysOffsetPrecise, error) {
+	var value PtpSysOffsetPrecise
+	err := ioctlPtr(fd, PTP_SYS_OFFSET_PRECISE2, unsafe.Pointer(&value))
+	return &value, err
+}
+
+// IoctlPtpSysOffsetExtended returns an extended description of the
+// clock offset compared to the system clock. The samples parameter
+// specifies the desired number of measurements.
+func IoctlPtpSysOffsetExtended(fd int, samples uint) (*PtpSysOffsetExtended, error) {
+	value := PtpSysOffsetExtended{Samples: uint32(samples)}
+	err := ioctlPtr(fd, PTP_SYS_OFFSET_EXTENDED2, unsafe.Pointer(&value))
+	return &value, err
+}
+
+// IoctlPtpPinGetfunc returns the configuration of the specified
+// I/O pin on given PTP device.
+func IoctlPtpPinGetfunc(fd int, index uint) (*PtpPinDesc, error) {
+	value := PtpPinDesc{Index: uint32(index)}
+	err := ioctlPtr(fd, PTP_PIN_GETFUNC2, unsafe.Pointer(&value))
+	return &value, err
+}
+
+// IoctlPtpPinSetfunc updates configuration of the specified PTP
+// I/O pin.
+func IoctlPtpPinSetfunc(fd int, pd *PtpPinDesc) error {
+	return ioctlPtr(fd, PTP_PIN_SETFUNC2, unsafe.Pointer(pd))
+}
+
+// IoctlPtpPeroutRequest configures the periodic output mode of the
+// PTP I/O pins.
+func IoctlPtpPeroutRequest(fd int, r *PtpPeroutRequest) error {
+	return ioctlPtr(fd, PTP_PEROUT_REQUEST2, unsafe.Pointer(r))
+}
+
+// IoctlPtpExttsRequest configures the external timestamping mode
+// of the PTP I/O pins.
+func IoctlPtpExttsRequest(fd int, r *PtpExttsRequest) error {
+	return ioctlPtr(fd, PTP_EXTTS_REQUEST2, unsafe.Pointer(r))
+}
+
 // IoctlGetWatchdogInfo fetches information about a watchdog device from the
 // Linux watchdog API. For more information, see:
 // https://www.kernel.org/doc/html/latest/watchdog/watchdog-api.html.

unix/linux/types.go

@@ -151,6 +151,7 @@ struct termios2 {
 #include <linux/openat2.h>
 #include <linux/perf_event.h>
 #include <linux/pps.h>
+#include <linux/ptp_clock.h>
 #include <linux/random.h>
 #include <linux/rtc.h>
 #include <linux/rtnetlink.h>
@@ -525,6 +526,15 @@ struct cachestat {
 	__u64 nr_evicted;
 	__u64 nr_recently_evicted;
 };
+
+// the one defined in linux/ptp_clock.h has unions
+struct my_ptp_perout_request {
+	struct ptp_clock_time startOrPhase;	// start or phase
+	struct ptp_clock_time period;
+	unsigned int index;
+	unsigned int flags;
+	struct ptp_clock_time on;
+};
 */
 import "C"
 
@@ -4126,6 +4136,18 @@ const (
 	HWTSTAMP_TX_ONESTEP_SYNC = C.HWTSTAMP_TX_ONESTEP_SYNC
 )
 
+type (
+	PtpClockCaps C.struct_ptp_clock_caps
+	PtpClockTime C.struct_ptp_clock_time
+	PtpExttsEvent C.struct_ptp_extts_event
+	PtpExttsRequest C.struct_ptp_extts_request
+	PtpPeroutRequest C.struct_my_ptp_perout_request
+	PtpPinDesc C.struct_ptp_pin_desc
+	PtpSysOffset C.struct_ptp_sys_offset
+	PtpSysOffsetExtended C.struct_ptp_sys_offset_extended
+	PtpSysOffsetPrecise C.struct_ptp_sys_offset_precise
+)
+
 type (
 	HIDRawReportDescriptor C.struct_hidraw_report_descriptor
 	HIDRawDevInfo          C.struct_hidraw_devinfo

unix/mkerrors.sh

@@ -266,6 +266,7 @@ struct ltchars {
 #include <linux/nsfs.h>
 #include <linux/perf_event.h>
 #include <linux/pps.h>
+#include <linux/ptp_clock.h>
 #include <linux/ptrace.h>
 #include <linux/random.h>
 #include <linux/reboot.h>
@@ -537,6 +538,7 @@ ccflags="$@"
 		$2 ~ /^(AF|SOCK|SO|SOL|IPPROTO|IP|IPV6|TCP|MCAST|EVFILT|NOTE|SHUT|PROT|MAP|MREMAP|MFD|T?PACKET|MSG|SCM|MCL|DT|MADV|PR|LOCAL|TCPOPT|UDP)_/ ||
 		$2 ~ /^NFC_(GENL|PROTO|COMM|RF|SE|DIRECTION|LLCP|SOCKPROTO)_/ ||
 		$2 ~ /^NFC_.*_(MAX)?SIZE$/ ||
+		$2 ~ /^PTP_/ ||
 		$2 ~ /^RAW_PAYLOAD_/ ||
 		$2 ~ /^[US]F_/ ||
 		$2 ~ /^TP_STATUS_/ ||

unix/mkpost.go

@@ -185,6 +185,15 @@ func main() {
 		b = bytes.Replace(b, s, newNames, 1)
 	}
 
+	// Convert []int8 to []byte in PtpPinDesc
+	ptpBytesRegex := regexp.MustCompile(`(Name)(\s+)\[(\d+)\]u?int8`)
+	ptpIoctlType := regexp.MustCompile(`PtpPinDesc\s+struct {[^}]*}`)
+	ptpStructs := ptpIoctlType.FindAll(b, -1)
+	for _, s := range ptpStructs {
+		newNames := ptpBytesRegex.ReplaceAll(s, []byte("$1$2[$3]byte"))
+		b = bytes.Replace(b, s, newNames, 1)
+	}
+
 	// Convert []int8 to []byte in ctl_info ioctl interface
 	convertCtlInfoName := regexp.MustCompile(`(Name)(\s+)\[(\d+)\]int8`)
 	ctlInfoType := regexp.MustCompile(`type CtlInfo struct {[^}]*}`)