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hwtstamp_ctl: use SIOCGHWTSTAMP ioctl before destructively setting policy 

This patch modifies the hwtstamp_ctl program, so that it will (attempt
to) use the SIOCGHWTSTAMP ioctl to non-destructively read the current
hardware timestamping policy, prior to setting it with SIOCSHWTSTAMP.

This change has 3 primary advantages:

1) It allows reading the current settings of the device, which was
   previously not possible since SIOCSHWTSTAMP is destructive.
2) The default behavior without rx-filter or tx-type selected on the
   command line is no longer destructive, since it does not attempt to
   set the values to 0. The user must explicitly request to disable the
   settings, by using the provided options.
3) It allows only modifying tx-type or rx-filter separately, without
   destroying the other setting.

This patch supersedes a previous submission which added a -g flag. This
new method of getting first is more advantageous and doesn't require
adding an additional option flag.

- v4
* only display results if command succeeds, as the contents are otherwise
  expected to be identical to what we passed in.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
master
Jacob Keller 2014-06-03 14:03:11 -07:00 committed by Richard Cochran
parent 5e8a34f0b4
commit 2462f675c3
2 changed files with 58 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
hwstamp_ctl.8
View File

@ -15,7 +15,7 @@ hwstamp_ctl \- set time stamping policy at the driver level
.SH DESCRIPTION
.B hwstamp_ctl
is a program used to set the hardware time stamping policy at the network
is a program used to set and get the hardware time stamping policy at the network
driver level with the
.B SIOCSHWTSTAMP
.BR ioctl (2).
@ -27,6 +27,15 @@ values are hints to the driver what it is expected to do. If the requested
fine-grained filtering for incoming packets is not supported, the driver may
time stamp more than just the requested types of packets.
If neither
.I tx-type
nor
.I rx-filter
values are passed to the program, it will use the
.B SIOCGHWTSTAMP
.BR ioctl(2)
to non-destructively read the current hardware time stamping policy.
This program is a debugging tool. The
.BR ptp4l (8)
program does not need this program to function, it will set the policy

51
hwstamp_ctl.c
View File

@ -30,6 +30,7 @@
#include <net/if.h>
#include "version.h"
#include "missing.h"
static void usage(char *progname)
{
@ -84,6 +85,7 @@ int main(int argc, char *argv[])
struct hwtstamp_config cfg;
char *device = NULL, *progname;
int c, err, fd, rxopt = HWTSTAMP_FILTER_NONE, txopt = HWTSTAMP_TX_OFF;
int setrx = 0, settx = 0;
/* Process the command line arguments. */
progname = strrchr(argv[0], '/');
@ -94,9 +96,11 @@ int main(int argc, char *argv[])
device = optarg;
break;
case 'r':
setrx = 1;
rxopt = atoi(optarg);
break;
case 't':
settx = 1;
txopt = atoi(optarg);
break;
case 'v':
@ -116,6 +120,7 @@ int main(int argc, char *argv[])
usage(progname);
return -1;
}
if (rxopt < HWTSTAMP_FILTER_NONE ||
rxopt > HWTSTAMP_FILTER_PTP_V2_DELAY_REQ ||
txopt < HWTSTAMP_TX_OFF || txopt > HWTSTAMP_TX_ON) {
@ -129,8 +134,6 @@ int main(int argc, char *argv[])
strncpy(ifreq.ifr_name, device, sizeof(ifreq.ifr_name));
ifreq.ifr_data = (void *) &cfg;
cfg.tx_type = txopt;
cfg.rx_filter = rxopt;
fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (fd < 0) {
@ -138,15 +141,53 @@ int main(int argc, char *argv[])
return -1;
}
/* First, attempt to get the current settings. */
err = ioctl(fd, SIOCGHWTSTAMP, &ifreq);
if (err < 0) {
err = errno;
if (err == ENOTTY)
fprintf(stderr,
"Kernel does not have support "
"for non-destructive SIOCGHWTSTAMP.\n");
else if (err == EOPNOTSUPP)
fprintf(stderr,
"Device driver does not have support "
"for non-destructive SIOCGHWTSTAMP.\n");
else
perror("SIOCGHWTSTAMP failed");
} else {
printf("current settings:\n"
"tx_type %d\n"
"rx_filter %d\n",
cfg.tx_type, cfg.rx_filter);
}
/* Now, attempt to set values. Only change the values actually
* requested by user, rather than blindly resetting th zero if
* unrequested. */
if (settx || setrx) {
if (settx)
cfg.tx_type = txopt;
if (setrx)
cfg.rx_filter = rxopt;
err = ioctl(fd, SIOCSHWTSTAMP, &ifreq);
if (err < 0) {
err = errno;
perror("SIOCSHWTSTAMP failed");
if (err == ERANGE)
fprintf(stderr, "The requested time stamping mode is not supported by the hardware.\n");
fprintf(stderr,
"The requested time stamping mode is "
"not supported by the hardware.\n");
} else {
printf("new settings:\n"
"tx_type %d\n"
"rx_filter %d\n",
cfg.tx_type, cfg.rx_filter);
}
}
printf("tx_type %d\n" "rx_filter %d\n", cfg.tx_type, cfg.rx_filter);
return err;
}