On Tue, 4 Feb 2025, Hal Murray wrote:
As Alice would say, "curiouser and curiouser". Just when I think I've
figured out the reason for one bit of bizarreness, you find another. :-)
I think the current code works on all my systems.
What's the breakdown in the 32-bit NetBSD case? One would hope that the
payload is 64+32 and not vice versa.
#define NTP_SIZEOF_LONG 4 /* Size of long from <None> */
#define NTP_SIZEOF_STRUCT_TIMESPEC 12 /* Size of struct timespec from
<time.h> *
/
#define NTP_SIZEOF_STRUCT_TIMEVAL 12 /* Size of struct timeval from
<sys/time.h>
*/
#define NTP_SIZEOF_TIME_T 8 /* Size of time_t from <time.h> */
[This is an example of why I want that sizeof stuff.]
By "breakdown" I meant the sizes actually seen by the compiler, not some
separately derived macros.
I decided that it's best just to have an easily run standalone test for
this issue, rather than relying on hacking ntpd itself. I have a little
more work to do on it, and will submit it as a separate MR (for the
'attic') when I'm done.
One thing I've found already is that those apparent 20-byte payloads are
bogus. What's actually happening in those cases is that the *header* is
getting padded to a 64-bit boundary. This is reflected in the behavior of
CMSG_DATA, but not in sizeof(struct cmsghdr).
After I finish the test program, I'll revisit the actual fix, in light of
new understanding.
Fred Wright
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