On Wed, 11 Oct 2006 15:22:57 -0400
Jeff Garzik <[email protected]> wrote:
> Linux Kernel Mailing List wrote:
> > commit e0ab2928cc2202f13f0574d4c6f567f166d307eb
> > tree 3df0b8e340b1a98cd8a2daa19672ff008e8fb7f9
> > parent b611967de4dc5c52049676c4369dcac622a7cdfe
> > author Stephane Eranian <[email protected]> 1160554905 -0700
> > committer Linus Torvalds <[email protected]> 1160590461 -0700
> >
> > [PATCH] Add carta_random32() library routine
> >
> > This is a follow-up patch based on the review for perfmon2. This patch
> > adds the carta_random32() library routine + carta_random32.h header file.
> >
> > This is fast, simple, and efficient pseudo number generator algorithm. We
> > use it in perfmon2 to randomize the sampling periods. In this context, we
> > do not need any fancy randomizer.
>
> hrm, does this really warrant inclusion into every kernel build, on
> every platform?
>
> Jeff
>
Wouldn't existing net_random() work?
--
Stephen Hemminger <[email protected]>
On Wed, 11 Oct 2006 12:29:38 -0700
Stephen Hemminger <[email protected]> wrote:
> On Wed, 11 Oct 2006 15:22:57 -0400
> Jeff Garzik <[email protected]> wrote:
>
> > Linux Kernel Mailing List wrote:
> > > commit e0ab2928cc2202f13f0574d4c6f567f166d307eb
> > > tree 3df0b8e340b1a98cd8a2daa19672ff008e8fb7f9
> > > parent b611967de4dc5c52049676c4369dcac622a7cdfe
> > > author Stephane Eranian <[email protected]> 1160554905 -0700
> > > committer Linus Torvalds <[email protected]> 1160590461 -0700
> > >
> > > [PATCH] Add carta_random32() library routine
> > >
> > > This is a follow-up patch based on the review for perfmon2. This patch
> > > adds the carta_random32() library routine + carta_random32.h header file.
> > >
> > > This is fast, simple, and efficient pseudo number generator algorithm. We
> > > use it in perfmon2 to randomize the sampling periods. In this context, we
> > > do not need any fancy randomizer.
> >
> > hrm, does this really warrant inclusion into every kernel build, on
> > every platform?
> >
> > Jeff
> >
>
> Wouldn't existing net_random() work?
>
It might do, but someone went and hid it in networking and nobody knew
about it.
Stephane?
Make net_random() more widely available by calling it random32
Signed-off-by: Stephen Hemminger <[email protected]>
---
include/linux/net.h | 5 +-
include/linux/random.h | 3 +
lib/Makefile | 2 -
lib/random32.c | 135 ++++++++++++++++++++++++++++++++++++++++++++++++
net/core/dev.c | 2 -
net/core/utils.c | 116 -----------------------------------------
6 files changed, 141 insertions(+), 122 deletions(-)
diff --git a/include/linux/net.h b/include/linux/net.h
index c257f71..5d4240e 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -193,9 +193,8 @@ extern int sock_map_fd(struct sock
extern struct socket *sockfd_lookup(int fd, int *err);
#define sockfd_put(sock) fput(sock->file)
extern int net_ratelimit(void);
-extern unsigned long net_random(void);
-extern void net_srandom(unsigned long);
-extern void net_random_init(void);
+
+#define net_random() random32()
extern int kernel_sendmsg(struct socket *sock, struct msghdr *msg,
struct kvec *vec, size_t num, size_t len);
diff --git a/include/linux/random.h b/include/linux/random.h
index 5d6456b..0248b30 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -69,6 +69,9 @@ #endif
unsigned int get_random_int(void);
unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
+u32 random32(void);
+void srandom32(u32 seed);
+
#endif /* __KERNEL___ */
#endif /* _LINUX_RANDOM_H */
diff --git a/lib/Makefile b/lib/Makefile
index 59070db..bffdc82 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -5,7 +5,7 @@ #
lib-y := ctype.o string.o vsprintf.o cmdline.o \
bust_spinlocks.o rbtree.o radix-tree.o dump_stack.o \
idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
- sha1.o irq_regs.o carta_random32.o
+ sha1.o irq_regs.o random32.o carta_random32.o
lib-$(CONFIG_MMU) += ioremap.o
lib-$(CONFIG_SMP) += cpumask.o
diff --git a/lib/random32.c b/lib/random32.c
new file mode 100644
index 0000000..a905769
--- /dev/null
+++ b/lib/random32.c
@@ -0,0 +1,135 @@
+/*
+ This is a maximally equidistributed combined Tausworthe generator
+ based on code from GNU Scientific Library 1.5 (30 Jun 2004)
+
+ x_n = (s1_n ^ s2_n ^ s3_n)
+
+ s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19))
+ s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25))
+ s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11))
+
+ The period of this generator is about 2^88.
+
+ From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
+ Generators", Mathematics of Computation, 65, 213 (1996), 203--213.
+
+ This is available on the net from L'Ecuyer's home page,
+
+ http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
+ ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
+
+ There is an erratum in the paper "Tables of Maximally
+ Equidistributed Combined LFSR Generators", Mathematics of
+ Computation, 68, 225 (1999), 261--269:
+ http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
+
+ ... the k_j most significant bits of z_j must be non-
+ zero, for each j. (Note: this restriction also applies to the
+ computer code given in [4], but was mistakenly not mentioned in
+ that paper.)
+
+ This affects the seeding procedure by imposing the requirement
+ s1 > 1, s2 > 7, s3 > 15.
+
+*/
+struct nrnd_state {
+ u32 s1, s2, s3;
+};
+
+static DEFINE_PER_CPU(struct nrnd_state, net_rand_state);
+
+static u32 __random32(struct nrnd_state *state)
+{
+#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
+
+ state->s1 = TAUSWORTHE(state->s1, 13, 19, 4294967294UL, 12);
+ state->s2 = TAUSWORTHE(state->s2, 2, 25, 4294967288UL, 4);
+ state->s3 = TAUSWORTHE(state->s3, 3, 11, 4294967280UL, 17);
+
+ return (state->s1 ^ state->s2 ^ state->s3);
+}
+
+static void __set_random32(struct nrnd_state *state, unsigned long s)
+{
+ if (s == 0)
+ s = 1; /* default seed is 1 */
+
+#define LCG(n) (69069 * n)
+ state->s1 = LCG(s);
+ state->s2 = LCG(state->s1);
+ state->s3 = LCG(state->s2);
+
+ /* "warm it up" */
+ __random32(state);
+ __random32(state);
+ __random32(state);
+ __random32(state);
+ __random32(state);
+ __random32(state);
+}
+
+/**
+ * random32 - pseudo random number generator
+ *
+ * A 32 bit pseudo-random number is generated using a fast
+ * algorithm suitable for simulation. This algorithm is NOT
+ * considered safe for cryptographic use.
+ */
+u32 random32(void)
+{
+ unsigned long r;
+ struct nrnd_state *state = &get_cpu_var(net_rand_state);
+ r = __random32(state);
+ put_cpu_var(state);
+ return r;
+}
+EXPORT_SYMBOL(random32);
+
+/**
+ * srandom32 - add entropy to pseudo random number generator
+ * @seed: seed value
+ *
+ * Add some additional seeding to the random32() pool.
+ * Note: this pool is per cpu so it only affects current CPU.
+ */
+void srandom32(u32 entropy)
+{
+ struct nrnd_state *state = &get_cpu_var(net_rand_state);
+ __net_srandom(state, state->s1^entropy);
+ put_cpu_var(state);
+}
+EXPORT_SYMBOL(srandom32);
+
+/*
+ * Generate some initially weak seeding values to allow
+ * to start the random32() engine.
+ */
+static void __init random32_init(void)
+{
+ int i;
+
+ for_each_possible_cpu(i) {
+ struct nrnd_state *state = &per_cpu(net_rand_state,i);
+ __net_srandom(state, i+jiffies);
+ }
+}
+core_initcall(random32_init);
+
+/*
+ * Generate better values after random number generator
+ * is fully initalized.
+ */
+static void __init random32_reseed(void)
+{
+ int i;
+ unsigned long seed;
+
+ for_each_possible_cpu(i) {
+ struct nrnd_state *state = &per_cpu(net_rand_state,i);
+
+ get_random_bytes(&seed, sizeof(seed));
+ __net_srandom(state, seed);
+ }
+ return 0;
+}
+late_initcall(random32_reseed);
diff --git a/net/core/dev.c b/net/core/dev.c
index 4d891be..81c426a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3502,8 +3502,6 @@ static int __init net_dev_init(void)
BUG_ON(!dev_boot_phase);
- net_random_init();
-
if (dev_proc_init())
goto out;
diff --git a/net/core/utils.c b/net/core/utils.c
index 94c5d76..d93fe64 100644
--- a/net/core/utils.c
+++ b/net/core/utils.c
@@ -30,119 +30,6 @@ #include <asm/byteorder.h>
#include <asm/system.h>
#include <asm/uaccess.h>
-/*
- This is a maximally equidistributed combined Tausworthe generator
- based on code from GNU Scientific Library 1.5 (30 Jun 2004)
-
- x_n = (s1_n ^ s2_n ^ s3_n)
-
- s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19))
- s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25))
- s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11))
-
- The period of this generator is about 2^88.
-
- From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
- Generators", Mathematics of Computation, 65, 213 (1996), 203--213.
-
- This is available on the net from L'Ecuyer's home page,
-
- http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
- ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
-
- There is an erratum in the paper "Tables of Maximally
- Equidistributed Combined LFSR Generators", Mathematics of
- Computation, 68, 225 (1999), 261--269:
- http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
-
- ... the k_j most significant bits of z_j must be non-
- zero, for each j. (Note: this restriction also applies to the
- computer code given in [4], but was mistakenly not mentioned in
- that paper.)
-
- This affects the seeding procedure by imposing the requirement
- s1 > 1, s2 > 7, s3 > 15.
-
-*/
-struct nrnd_state {
- u32 s1, s2, s3;
-};
-
-static DEFINE_PER_CPU(struct nrnd_state, net_rand_state);
-
-static u32 __net_random(struct nrnd_state *state)
-{
-#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
-
- state->s1 = TAUSWORTHE(state->s1, 13, 19, 4294967294UL, 12);
- state->s2 = TAUSWORTHE(state->s2, 2, 25, 4294967288UL, 4);
- state->s3 = TAUSWORTHE(state->s3, 3, 11, 4294967280UL, 17);
-
- return (state->s1 ^ state->s2 ^ state->s3);
-}
-
-static void __net_srandom(struct nrnd_state *state, unsigned long s)
-{
- if (s == 0)
- s = 1; /* default seed is 1 */
-
-#define LCG(n) (69069 * n)
- state->s1 = LCG(s);
- state->s2 = LCG(state->s1);
- state->s3 = LCG(state->s2);
-
- /* "warm it up" */
- __net_random(state);
- __net_random(state);
- __net_random(state);
- __net_random(state);
- __net_random(state);
- __net_random(state);
-}
-
-
-unsigned long net_random(void)
-{
- unsigned long r;
- struct nrnd_state *state = &get_cpu_var(net_rand_state);
- r = __net_random(state);
- put_cpu_var(state);
- return r;
-}
-
-
-void net_srandom(unsigned long entropy)
-{
- struct nrnd_state *state = &get_cpu_var(net_rand_state);
- __net_srandom(state, state->s1^entropy);
- put_cpu_var(state);
-}
-
-void __init net_random_init(void)
-{
- int i;
-
- for_each_possible_cpu(i) {
- struct nrnd_state *state = &per_cpu(net_rand_state,i);
- __net_srandom(state, i+jiffies);
- }
-}
-
-static int net_random_reseed(void)
-{
- int i;
- unsigned long seed;
-
- for_each_possible_cpu(i) {
- struct nrnd_state *state = &per_cpu(net_rand_state,i);
-
- get_random_bytes(&seed, sizeof(seed));
- __net_srandom(state, seed);
- }
- return 0;
-}
-late_initcall(net_random_reseed);
-
int net_msg_cost = 5*HZ;
int net_msg_burst = 10;
@@ -153,10 +40,7 @@ int net_ratelimit(void)
{
return __printk_ratelimit(net_msg_cost, net_msg_burst);
}
-
-EXPORT_SYMBOL(net_random);
EXPORT_SYMBOL(net_ratelimit);
-EXPORT_SYMBOL(net_srandom);
/*
* Convert an ASCII string to binary IP.
--
1.4.1
From: Stephen Hemminger <[email protected]>
Date: Thu, 12 Oct 2006 10:26:38 -0700
>
> Make net_random() more widely available by calling it random32
>
> Signed-off-by: Stephen Hemminger <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
On Thu, Oct 12, 2006 at 10:26:38AM -0700, Stephen Hemminger wrote:
>
> Make net_random() more widely available by calling it random32
>...
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -5,7 +5,7 @@ #
> lib-y := ctype.o string.o vsprintf.o cmdline.o \
> bust_spinlocks.o rbtree.o radix-tree.o dump_stack.o \
> idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
> - sha1.o irq_regs.o carta_random32.o
> + sha1.o irq_regs.o random32.o carta_random32.o
>...
> --- /dev/null
> +++ b/lib/random32.c
>...
> +EXPORT_SYMBOL(random32);
>...
> +EXPORT_SYMBOL(srandom32);
>...
EXPORT_SYMBOL's in lib-y are latent bugs (IMHO kbuild should error
on them):
The problem is that if only modules use these functions, they will be
omitted from the kernel image.
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed
On Fri, 13 Oct 2006 20:19:22 +0200
Adrian Bunk <[email protected]> wrote:
> On Thu, Oct 12, 2006 at 10:26:38AM -0700, Stephen Hemminger wrote:
> >
> > Make net_random() more widely available by calling it random32
> >...
> > --- a/lib/Makefile
> > +++ b/lib/Makefile
> > @@ -5,7 +5,7 @@ #
> > lib-y := ctype.o string.o vsprintf.o cmdline.o \
> > bust_spinlocks.o rbtree.o radix-tree.o dump_stack.o \
> > idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
> > - sha1.o irq_regs.o carta_random32.o
> > + sha1.o irq_regs.o random32.o carta_random32.o
> >...
> > --- /dev/null
> > +++ b/lib/random32.c
> >...
> > +EXPORT_SYMBOL(random32);
> >...
> > +EXPORT_SYMBOL(srandom32);
> >...
>
> EXPORT_SYMBOL's in lib-y are latent bugs (IMHO kbuild should error
> on them):
>
> The problem is that if only modules use these functions, they will be
> omitted from the kernel image.
>
> cu
> Adrian
>
The main net code uses the code so it isn't really an issue in this case.
On Fri, 13 Oct 2006 20:19:22 +0200
Adrian Bunk <[email protected]> wrote:
> On Thu, Oct 12, 2006 at 10:26:38AM -0700, Stephen Hemminger wrote:
> >
> > Make net_random() more widely available by calling it random32
> >...
> > --- a/lib/Makefile
> > +++ b/lib/Makefile
> > @@ -5,7 +5,7 @@ #
> > lib-y := ctype.o string.o vsprintf.o cmdline.o \
> > bust_spinlocks.o rbtree.o radix-tree.o dump_stack.o \
> > idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
> > - sha1.o irq_regs.o carta_random32.o
> > + sha1.o irq_regs.o random32.o carta_random32.o
> >...
> > --- /dev/null
> > +++ b/lib/random32.c
> >...
> > +EXPORT_SYMBOL(random32);
> >...
> > +EXPORT_SYMBOL(srandom32);
> >...
>
> EXPORT_SYMBOL's in lib-y are latent bugs (IMHO kbuild should error
> on them):
>
> The problem is that if only modules use these functions, they will be
> omitted from the kernel image.
>
Yeah, I always get those two confused. I moved it to obj-y, thanks.
From: Andrew Morton <[email protected]>
Date: Fri, 13 Oct 2006 12:09:56 -0700
> On Fri, 13 Oct 2006 20:19:22 +0200
> Adrian Bunk <[email protected]> wrote:
>
> > EXPORT_SYMBOL's in lib-y are latent bugs (IMHO kbuild should error
> > on them):
> >
> > The problem is that if only modules use these functions, they will be
> > omitted from the kernel image.
> >
> Yeah, I always get those two confused. I moved it to obj-y, thanks.
Yep, good catch Adrian. I've been burned by this one oto.
> EXPORT_SYMBOL's in lib-y are latent bugs (IMHO kbuild should error
> on them):
In practice module will not load becasue it cannot resolve symbol - right?
That aside we should not export symbols from lib-y. But I have not any good
idea how to catch this during build time unles doing some ugly grep magic.
One thing that could be done would be to check for a specific section
(__ksymtab_strings) in the .o file only for lib-y .o files.
The check could be something like:
objdump -h <file.o> | grep __ksymtab_strings
If grep give error code '0' then we exported a symbol.
I may try to cook up later this weekend.
Sam
On Fri, Oct 13, 2006 at 08:19:22PM +0200, Adrian Bunk wrote:
> > --- /dev/null
> > +++ b/lib/random32.c
> >...
> > +EXPORT_SYMBOL(random32);
> >...
> > +EXPORT_SYMBOL(srandom32);
> >...
>
> EXPORT_SYMBOL's in lib-y are latent bugs (IMHO kbuild should error
> on them):
>
> The problem is that if only modules use these functions, they will be
> omitted from the kernel image.
In fact we should really really just kill lib-y completely. Leaving
the control of what gets built in to the linker shound like a really
bad idea in our enviroment.