Commit 46234253 authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by David S. Miller
Browse files

net: move net_get_random_once to lib 



There's no good reason why users outside of networking should not
be using this facility, f.e. for initializing their seeds.

Therefore, make it accessible from there as get_random_once().

Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 28335a74

include/linux/net.h

+4 −17
Original line number Diff line number Diff line
@@ -24,7 +24,8 @@ 
#include <linux/fcntl.h>	/* For O_CLOEXEC and O_NONBLOCK */

#include <linux/kmemcheck.h>

#include <linux/rcupdate.h>

#include <linux/jump_label.h>

#include <linux/once.h>



#include <uapi/linux/net.h>



struct poll_table_struct;
@@ -250,22 +251,8 @@ do { \ 
	} while (0)

#endif



bool __net_get_random_once(void *buf, int nbytes, bool *done,

			   struct static_key *done_key);



#define net_get_random_once(buf, nbytes)			\

	({								\

		bool ___ret = false;					\

		static bool ___done = false;				\

		static struct static_key ___once_key =			\

			STATIC_KEY_INIT_TRUE;				\

		if (static_key_true(&___once_key))			\

			___ret = __net_get_random_once(buf,		\

						       nbytes,		\

						       &___done,	\

						       &___once_key);	\

		___ret;							\

	})

	get_random_once((buf), (nbytes))



int kernel_sendmsg(struct socket *sock, struct msghdr *msg, struct kvec *vec,

		   size_t num, size_t len);

include/linux/once.h

0 → 100644
+24 −0
Original line number Diff line number Diff line 
#ifndef _LINUX_ONCE_H

#define _LINUX_ONCE_H



#include <linux/types.h>

#include <linux/jump_label.h>



bool __get_random_once(void *buf, int nbytes, bool *done,

		       struct static_key *once_key);



#define get_random_once(buf, nbytes)					\

	({								\

		bool ___ret = false;					\

		static bool ___done = false;				\

		static struct static_key ___once_key =			\

			STATIC_KEY_INIT_TRUE;				\

		if (static_key_true(&___once_key))			\

			___ret = __get_random_once((buf),		\

						   (nbytes),		\

						   &___done,		\

						   &___once_key);	\

		___ret;							\

	})



#endif /* _LINUX_ONCE_H */

lib/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -26,7 +26,8 @@ obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ 
	 bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \

	 gcd.o lcm.o list_sort.o uuid.o flex_array.o iov_iter.o clz_ctz.o \

	 bsearch.o find_bit.o llist.o memweight.o kfifo.o \

	 percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o

	 percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o \

	 once.o

obj-y += string_helpers.o

obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o

obj-y += hexdump.o

lib/once.c

0 → 100644
+54 −0
Original line number Diff line number Diff line 
#include <linux/slab.h>

#include <linux/spinlock.h>

#include <linux/once.h>

#include <linux/random.h>



struct __random_once_work {

	struct work_struct work;

	struct static_key *key;

};



static void __random_once_deferred(struct work_struct *w)

{

	struct __random_once_work *work;



	work = container_of(w, struct __random_once_work, work);

	BUG_ON(!static_key_enabled(work->key));

	static_key_slow_dec(work->key);

	kfree(work);

}



static void __random_once_disable_jump(struct static_key *key)

{

	struct __random_once_work *w;



	w = kmalloc(sizeof(*w), GFP_ATOMIC);

	if (!w)

		return;



	INIT_WORK(&w->work, __random_once_deferred);

	w->key = key;

	schedule_work(&w->work);

}



bool __get_random_once(void *buf, int nbytes, bool *done,

		       struct static_key *once_key)

{

	static DEFINE_SPINLOCK(lock);

	unsigned long flags;



	spin_lock_irqsave(&lock, flags);

	if (*done) {

		spin_unlock_irqrestore(&lock, flags);

		return false;

	}



	get_random_bytes(buf, nbytes);

	*done = true;

	spin_unlock_irqrestore(&lock, flags);



	__random_once_disable_jump(once_key);



	return true;

}

EXPORT_SYMBOL(__get_random_once);

net/core/utils.c

+0 −49
Original line number Diff line number Diff line
@@ -348,52 +348,3 @@ void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb, 
	}

}

EXPORT_SYMBOL(inet_proto_csum_replace_by_diff);
 


struct __net_random_once_work {

	struct work_struct work;

	struct static_key *key;

};



static void __net_random_once_deferred(struct work_struct *w)

{

	struct __net_random_once_work *work =

		container_of(w, struct __net_random_once_work, work);

	BUG_ON(!static_key_enabled(work->key));

	static_key_slow_dec(work->key);

	kfree(work);

}



static void __net_random_once_disable_jump(struct static_key *key)

{

	struct __net_random_once_work *w;



	w = kmalloc(sizeof(*w), GFP_ATOMIC);

	if (!w)

		return;



	INIT_WORK(&w->work, __net_random_once_deferred);

	w->key = key;

	schedule_work(&w->work);

}



bool __net_get_random_once(void *buf, int nbytes, bool *done,

			   struct static_key *once_key)

{

	static DEFINE_SPINLOCK(lock);

	unsigned long flags;



	spin_lock_irqsave(&lock, flags);

	if (*done) {

		spin_unlock_irqrestore(&lock, flags);

		return false;

	}



	get_random_bytes(buf, nbytes);

	*done = true;

	spin_unlock_irqrestore(&lock, flags);



	__net_random_once_disable_jump(once_key);



	return true;

}

EXPORT_SYMBOL(__net_get_random_once);

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