On Mon, 2022-11-14 at 14:25 +0100, Luigi Mantellini wrote:
> The PortId is defined as a couple of ClockId (an 8-bytes opaque) and
> the PortNumber (UInterger16).
> In order to correctly handle the PortId endianess, the comparison has
> been split in the ClockIds comparison (using memcmp) and PortNumber
> comparison.
You code do not solve any endianess issue.
The clock ID is byte stream.
And port number is 16 bits, it require converting from network order to
host order, which you do not need here. Becuase port ID are already in
the same endian here.
As struct PortIdentity is defined as "PACKED", it should not have any
pad that may cause the memory compare to fail. Of having different
values in the pad.
So memcmp and your "portid_cmp" should give the same result.
I would suggest to replace the memcmp and "portid_cmp" with existing
pid_eq(const struct PortIdentity *a, const struct PortIdentity *b)
And debug and find the real reason you have the bug.
And than send a real bug fix :-)
Erez
> ---
> bmc.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/bmc.c b/bmc.c
> index 6ac7aa0..ebc0789 100644
> --- a/bmc.c
> +++ b/bmc.c
> @@ -21,6 +21,17 @@
> #include "bmc.h"
> #include "ds.h"
>
> +static int portid_cmp(struct PortIdentity *a, struct PortIdentity
> *b)
> +{
> + int diff = memcmp(&a->clockIdentity, &b->clockIdentity,
> sizeof(a->clockIdentity));
> +
> + if (diff == 0) {
> + diff = a->portNumber - b->portNumber;
> + }
> +
> + return diff;
> +}
> +
> int dscmp2(struct dataset *a, struct dataset *b)
> {
> int diff;
> @@ -35,7 +46,7 @@ int dscmp2(struct dataset *a, struct dataset *b)
> * standard, since there is nothing we can do about it
> anyway.
> */
> if (A < B) {
> - diff = memcmp(&b->receiver, &b->sender, sizeof(b-
> >receiver));
> + diff = portid_cmp(&b->receiver, &b->sender);
> if (diff < 0)
> return A_BETTER;
> if (diff > 0)
> @@ -44,7 +55,7 @@ int dscmp2(struct dataset *a, struct dataset *b)
> return 0;
> }
> if (A > B) {
> - diff = memcmp(&a->receiver, &a->sender, sizeof(a-
> >receiver));
> + diff = portid_cmp(&a->receiver, &a->sender);
> if (diff < 0)
> return B_BETTER;
> if (diff > 0)
> @@ -53,7 +64,7 @@ int dscmp2(struct dataset *a, struct dataset *b)
> return 0;
> }
>
> - diff = memcmp(&a->sender, &b->sender, sizeof(a->sender));
> + diff = portid_cmp(&a->sender, &b->sender);
> if (diff < 0)
> return A_BETTER_TOPO;
> if (diff > 0)
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