spelling

ok gnezdo@ semarie@ mpi@

move arc4random prototype to systm.h. more appropriate for most code
to include that than rdnvar.h. ok deraadt dlg

- use nitems(); no binary change

ok claudio@

rename arc4random_bytes => arc4random_buf to match libc's nicer name;
ok deraadt@

revert - I'm a dumbfuck who doesn't know his own API

off by one at end of array

Because the ip_id code initialisation is a specific case of shuffling
a set of incrementing integers (and not an arbitrary set of values) it
is possible to populate the array as we shuffle it in a single forward
pass. Clever optimisation from didickman AT gmail.com;
ok deraadt@ mcbride@

because arc4random_uniform is being used, the modulo bias is taken care of

Add a arc4random_uniform() that returns a uniformly distributed number
in the range 0 <= x < upper_bound

Please use this new API instead of "arc4random() % upper_bound", as it
avoids the "modulo bias" that favours small results when upper_bound is
not a power of two.

feedback deraadt@ mcbride@; ok deraadt@

replacement algorithm. initialize a 64K-short buffer using Durstenfeld
shuffle. Upon allocation, swap-permute the new value to a random slot in
the 0..32K-1 th entry of the buffer as we move forward, ensuring randomness
but also satisfying the non-repeating property we need. Also avoid the value
of 0, since IP ID's of 0 are special. Inspired by Dillon's implementation.
We believe this is easier to read though, initializes with less bias, handles
the ID of 0 properly, and wins speed tests.
Thanks a lot to mcbride and djm for doing a bunch of statistical and speed
analysis, and comments from nordin
ok mcbride djm

typos; ok jmc@
sys/netinet/in_pcb.c and sys/net/bridgestp.c ok henning@
sys/dev/pci/bktr/* ok jakemsr@

remove more static to avoid confusing the profiler (and maybe ddb too)

prodded by art@ ja ja claudio@

First step towards more sane time handling in the kernel -- this changes
things such that code that only need a second-resolution uptime or wall
time, and used to get that from time.tv_secs or mono_time.tv_secs now get
this from separate time_t globals time_second and time_uptime.

ok art@ niklas@ nordin@

spelling; jjy2+@pitt.edu

niels kindly dropped clause 3/4 from the license. tnx!

previous commit included bad hunk. sorry

no need to call arc4random() if we don't skip numbers in ip_randomid().
from markus

correct non-repetitive ID code, based on comments from niels provos.
- seed2 is necessary, but use it as "seed2 + x" not "seed2 ^ x".
- skipping number is not needed, so disable it for 16bit generator (makes
the repetition period to 30000)

"exp" is a reserved symbol under gcc3/posix. mcbride ok

Kill #if __STDC__ used to do K&R vs. ANSI varargs/stdarg; just do things
the ANSI way.

First round of __P removal in sys

branches: 1.4.4;
Cut down on include files.

use faster arc4random() for small amounts fo data, some spaces; niels ok

branches: 1.2.4;
add an inner xor to make prediction attacks against the ids harder, due
to an attack pointed out by David Wagner.

make ip_id random but ensure that ids dont repeat for some period.

move arc4random prototype to systm.h. more appropriate for most code
to include that than rdnvar.h. ok deraadt dlg

- use nitems(); no binary change

ok claudio@

rename arc4random_bytes => arc4random_buf to match libc's nicer name;
ok deraadt@

revert - I'm a dumbfuck who doesn't know his own API

off by one at end of array

Because the ip_id code initialisation is a specific case of shuffling
a set of incrementing integers (and not an arbitrary set of values) it
is possible to populate the array as we shuffle it in a single forward
pass. Clever optimisation from didickman AT gmail.com;
ok deraadt@ mcbride@

because arc4random_uniform is being used, the modulo bias is taken care of

Add a arc4random_uniform() that returns a uniformly distributed number
in the range 0 <= x < upper_bound

Please use this new API instead of "arc4random() % upper_bound", as it
avoids the "modulo bias" that favours small results when upper_bound is
not a power of two.

feedback deraadt@ mcbride@; ok deraadt@

replacement algorithm. initialize a 64K-short buffer using Durstenfeld
shuffle. Upon allocation, swap-permute the new value to a random slot in
the 0..32K-1 th entry of the buffer as we move forward, ensuring randomness
but also satisfying the non-repeating property we need. Also avoid the value
of 0, since IP ID's of 0 are special. Inspired by Dillon's implementation.
We believe this is easier to read though, initializes with less bias, handles
the ID of 0 properly, and wins speed tests.
Thanks a lot to mcbride and djm for doing a bunch of statistical and speed
analysis, and comments from nordin
ok mcbride djm

typos; ok jmc@
sys/netinet/in_pcb.c and sys/net/bridgestp.c ok henning@
sys/dev/pci/bktr/* ok jakemsr@

remove more static to avoid confusing the profiler (and maybe ddb too)

prodded by art@ ja ja claudio@

First step towards more sane time handling in the kernel -- this changes
things such that code that only need a second-resolution uptime or wall
time, and used to get that from time.tv_secs or mono_time.tv_secs now get
this from separate time_t globals time_second and time_uptime.

ok art@ niklas@ nordin@

spelling; jjy2+@pitt.edu

niels kindly dropped clause 3/4 from the license. tnx!

previous commit included bad hunk. sorry

no need to call arc4random() if we don't skip numbers in ip_randomid().
from markus

correct non-repetitive ID code, based on comments from niels provos.
- seed2 is necessary, but use it as "seed2 + x" not "seed2 ^ x".
- skipping number is not needed, so disable it for 16bit generator (makes
the repetition period to 30000)

"exp" is a reserved symbol under gcc3/posix. mcbride ok

Kill #if __STDC__ used to do K&R vs. ANSI varargs/stdarg; just do things
the ANSI way.

First round of __P removal in sys

branches: 1.4.4;
Cut down on include files.

use faster arc4random() for small amounts fo data, some spaces; niels ok

branches: 1.2.4;
add an inner xor to make prediction attacks against the ids harder, due
to an attack pointed out by David Wagner.

make ip_id random but ensure that ids dont repeat for some period.