Barry A. Warsaw <ba...@python.org> added the comment: On Nov 23, 2017, at 11:24, Serhiy Storchaka <rep...@bugs.python.org> wrote:
> Wait, now I understand the purpose of the current test! There is just a typo > in a comment, should be 41 instead of 47. The test itself is correct. If the > address is obtained from network cards, it should have the 41 bit clear. If > it is generated randomly, it should have the 41 bit set, to avoid conflicts > with addresses obtained from network cards. There is nothing about the 42 bit. It’s not just a typo in the comment, it’s a typo in the bitmask, at least if the intent of the test is to ensure that the MAC address is universally administered. That is defined as having a 0 in the “second least significant bit of the first octet”. Here’s a way to make that clearer. # Second least significant bit of the first octet of the 48-bit MAC address >>> 0b00000010_00000000_00000000_00000000_00000000_00000000 2199023255552 # Constant from the PR >>> 1<<41 2199023255552 # Literal bit mask from the original code. >>> 0x010000000000 1099511627776 The latter is off by 1 place. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue32107> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
