On Fri, Nov 18, 2022 at 08:43:19AM +0100, Luigi Mantellini wrote: > From: Luigi Mantellini <luigi.mantell...@gmail.com> > > The PortId is defined as a couple of ClockId (an 8-bytes opaque) and the > PortNumber (UInterger16). > > The current implementation compares the entire PortId, consisting of ClockId > and PortNumber, using a byte-to-byte comparison (memcmp). > This way doesn't consider the HOST's endianess on PortId part, giving wrong > results in same case. > > Consider the following setup (assuming the same ClockId) > > PortId_a = (ClockId, PortNumber=0x1234) > PortId_b = (ClockId, PortNumber=0x4512) > > On a LittleEndian HOST, we obtain the following memory setup: > > PortId_a = ... ClockId ... 0x34 0x12 > PortId_b = ... ClockId ... 0x12 0x45 > > Using just a memcmp() call we obtain the WRONG result PortId_a > PortId_b, > because the byte-to-byte comparison will check the PortNumber Lower-Byte > (0x34 vs 0x12) first. > > To fix the BCMA implementation we need to split the PortId comparison in: > > - ClockId comparison, still using memcmp() on a opaque byte stream > - PortNumber, using a natural semantic comparison between integer numbers.
Applied. Thanks, Richard _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
