Commit Graph

13 Commits

Author SHA1 Message Date
Pawel Jakub Dawidek
8c804c7c98 Correct typo. 2007-04-23 12:53:00 +00:00
Robert Watson
873fbcd776 Further system call comment cleanup:
- Remove also "MP SAFE" after prior "MPSAFE" pass. (suggested by bde)
- Remove extra blank lines in some cases.
- Add extra blank lines in some cases.
- Remove no-op comments consisting solely of the function name, the word
  "syscall", or the system call name.
- Add punctuation.
- Re-wrap some comments.
2007-03-05 13:10:58 +00:00
Stefan Farfeleder
c6e0a843cf Separate functions with a newline. 2006-07-17 21:00:42 +00:00
Marcel Moolenaar
125fbd3cdc Add parse_uuid() that creates a binary representation of an UUID from
a string representation.
2005-10-07 13:37:10 +00:00
Marcel Moolenaar
73130b2224 Move the UUID generator into its own function, called kern_uuidgen(),
so that UUIDs can be generated from within the kernel. The uuidgen(2)
syscall now allocates kernel memory, calls the generator, and does a
copyout() for the whole UUID store. This change is in support of GPT.
2005-09-18 21:40:15 +00:00
Warner Losh
9454b2d864 /* -> /*- for copyright notices, minor format tweaks as necessary 2005-01-06 23:35:40 +00:00
Ralf S. Engelschall
446655ac4f Fix generation of random multicast MAC address.
In case no real/physical IEEE 802 address is available, both the expired
"draft-leach-uuids-guids-01" (section "4. Node IDs when no IEEE 802
network card is available") and RFC 2518 (section "6.4.1 Node Field
Generation Without the IEEE 802 Address") recommend (quoted from RFC
2518):

  "The ideal solution is to obtain a 47 bit cryptographic quality random
  number, and use it as the low 47 bits of the node ID, with the _most_
  significant bit of the first octet of the node ID set to 1. This bit
  is the unicast/multicast bit, which will never be set in IEEE 802
  addresses obtained from network cards; hence, there can never be a
  conflict between UUIDs generated by machines with and without network
  cards."

Unfortunately, this incorrectly explains how to implement this and
the FreeBSD UUID generator code inherited this generation bug from
the broken reference code in the standards draft. They should instead
specify the "_least_ significant bit of the first octet of the node ID"
as the multicast bit in a memory and hexadecimal string representation
of a 48-bit IEEE 802 MAC address.

This standards bug arised from a false interpretation, as the multicast
bit is actually the _most_ significant bit in IEEE 802.3 (Ethernet)
_transmission order_ of an IEEE 802 MAC address. The standards authors
forgot that the bitwise order of an _octet_ from a MAC address _memory_
and hexadecimal string representation is still always from left (MSB,
bit 7) to right (LSB, bit 0).

Fortunately, this UUID generation bug could have occurred on systems
without any Ethernet NICs only.
2004-01-22 13:34:11 +00:00
David E. O'Brien
677b542ea2 Use __FBSDID(). 2003-06-11 00:56:59 +00:00
Poul-Henning Kamp
8313328657 Introduce {be,le}_uuid_{enc,dec}() functions for explicitly encoding
and decoding UUID's in big endian and little endian binary format.
2003-05-31 16:47:07 +00:00
Jeffrey Hsu
b30a244c34 SMP locking for ifnet list. 2002-12-22 05:35:03 +00:00
Bruce Evans
5fd65482e0 Include <sys/systm.h> for the declarations of many things instead of
depending on namespace pollution in <sys/mumble.h>.
2002-08-22 12:47:22 +00:00
John Baldwin
54a033896d Fix a minor whitespace style nit that broke 'grep ^uuidgen'. 2002-07-09 19:36:50 +00:00
Marcel Moolenaar
52183d0145 Add uuidgen(2) and uuidgen(1).
The uuidgen command, by means of the uuidgen syscall, generates one
or more Universally Unique Identifiers compatible with OSF/DCE 1.1
version 1 UUIDs.

From the Perforce logs (change 11995):

Round of cleanups:
o  Give uuidgen() the correct prototype in syscalls.master
o  Define struct uuid according to DCE 1.1 in sys/uuid.h
o  Use struct uuid instead of uuid_t. The latter is defined
   in sys/uuid.h but should not be used in kernel land.
o  Add snprintf_uuid(), printf_uuid() and sbuf_printf_uuid()
   to kern_uuid.c for use in the kernel (currently geom_gpt.c).
o  Rename the non-standard struct uuid in kern/kern_uuid.c
   to struct uuid_private and give it a slightly better definition
   for better byte-order handling. See below.
o  In sys/gpt.h, fix the broken uuid definitions to match the now
   compliant struct uuid definition. See below.
o  In usr.bin/uuidgen/uuidgen.c catch up with struct uuid change.

A note about byte-order:
        The standard failed to provide a non-conflicting and
unambiguous definition for the binary representation. My initial
implementation always wrote the timestamp as a 64-bit little-endian
(2s-complement) integral. The clock sequence was always written
as a 16-bit big-endian (2s-complement) integral. After a good
nights sleep and couple of Pan Galactic Gargle Blasters (not
necessarily in that order :-) I reread the spec and came to the
conclusion that the time fields are always written in the native
by order, provided the the low, mid and hi chopping still occurs.
The spec mentions that you "might need to swap bytes if you talk
to a machine that has a different byte-order". The clock sequence
is always written in big-endian order (as is the IEEE 802 address)
because its division is resulting in bytes, making the ordering
unambiguous.
2002-05-28 06:16:08 +00:00