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Commit fbc907f0 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

net: filter: move filter accounting to filter core 



This patch basically does two things, i) removes the extern keyword
from the include/linux/filter.h file to be more consistent with the
rest of Joe's changes, and ii) moves filter accounting into the filter
core framework.

Filter accounting mainly done through sk_filter_{un,}charge() take
care of the case when sockets are being cloned through sk_clone_lock()
so that removal of the filter on one socket won't result in eviction
as it's still referenced by the other.

These functions actually belong to net/core/filter.c and not
include/net/sock.h as we want to keep all that in a central place.
It's also not in fast-path so uninlining them is fine and even allows
us to get rd of sk_filter_release_rcu()'s EXPORT_SYMBOL and a forward
declaration.

Joint work with Alexei Starovoitov.

Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a3ea269b

include/linux/filter.h

+17 −13
Original line number Diff line number Diff line
@@ -50,28 +50,32 @@ static inline unsigned int sk_filter_size(unsigned int proglen) 
#define sk_filter_proglen(fprog)			\

		(fprog->len * sizeof(fprog->filter[0]))



extern int sk_filter(struct sock *sk, struct sk_buff *skb);

extern unsigned int sk_run_filter(const struct sk_buff *skb,

int sk_filter(struct sock *sk, struct sk_buff *skb);

unsigned int sk_run_filter(const struct sk_buff *skb,

			   const struct sock_filter *filter);



extern int sk_unattached_filter_create(struct sk_filter **pfp,

int sk_unattached_filter_create(struct sk_filter **pfp,

				struct sock_fprog *fprog);

extern void sk_unattached_filter_destroy(struct sk_filter *fp);

void sk_unattached_filter_destroy(struct sk_filter *fp);



extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);

extern int sk_detach_filter(struct sock *sk);

int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);

int sk_detach_filter(struct sock *sk);



extern int sk_chk_filter(struct sock_filter *filter, unsigned int flen);

extern int sk_get_filter(struct sock *sk, struct sock_filter __user *filter, unsigned len);

extern void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to);

int sk_chk_filter(struct sock_filter *filter, unsigned int flen);

int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,

		  unsigned int len);

void sk_decode_filter(struct sock_filter *filt, struct sock_filter *to);



void sk_filter_charge(struct sock *sk, struct sk_filter *fp);

void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);



#ifdef CONFIG_BPF_JIT

#include <stdarg.h>

#include <linux/linkage.h>

#include <linux/printk.h>



extern void bpf_jit_compile(struct sk_filter *fp);

extern void bpf_jit_free(struct sk_filter *fp);

void bpf_jit_compile(struct sk_filter *fp);

void bpf_jit_free(struct sk_filter *fp);



static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,

				u32 pass, void *image)

include/net/sock.h

+0 −27
Original line number Diff line number Diff line
@@ -1621,33 +1621,6 @@ void sk_common_release(struct sock *sk); 
/* Initialise core socket variables */

void sock_init_data(struct socket *sock, struct sock *sk);



void sk_filter_release_rcu(struct rcu_head *rcu);



/**

 *	sk_filter_release - release a socket filter

 *	@fp: filter to remove

 *

 *	Remove a filter from a socket and release its resources.

 */



static inline void sk_filter_release(struct sk_filter *fp)

{

	if (atomic_dec_and_test(&fp->refcnt))

		call_rcu(&fp->rcu, sk_filter_release_rcu);

}



static inline void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)

{

	atomic_sub(sk_filter_size(fp->len), &sk->sk_omem_alloc);

	sk_filter_release(fp);

}



static inline void sk_filter_charge(struct sock *sk, struct sk_filter *fp)

{

	atomic_inc(&fp->refcnt);

	atomic_add(sk_filter_size(fp->len), &sk->sk_omem_alloc);

}



/*

 * Socket reference counting postulates.

 *

net/core/filter.c

+25 −2
Original line number Diff line number Diff line
@@ -664,14 +664,37 @@ static void sk_release_orig_filter(struct sk_filter *fp) 
 * 	sk_filter_release_rcu - Release a socket filter by rcu_head

 *	@rcu: rcu_head that contains the sk_filter to free

 */

void sk_filter_release_rcu(struct rcu_head *rcu)

static void sk_filter_release_rcu(struct rcu_head *rcu)

{

	struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu);



	sk_release_orig_filter(fp);

	bpf_jit_free(fp);

}

EXPORT_SYMBOL(sk_filter_release_rcu);



/**

 *	sk_filter_release - release a socket filter

 *	@fp: filter to remove

 *

 *	Remove a filter from a socket and release its resources.

 */

static void sk_filter_release(struct sk_filter *fp)

{

	if (atomic_dec_and_test(&fp->refcnt))

		call_rcu(&fp->rcu, sk_filter_release_rcu);

}



void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp)

{

	atomic_sub(sk_filter_size(fp->len), &sk->sk_omem_alloc);

	sk_filter_release(fp);

}



void sk_filter_charge(struct sock *sk, struct sk_filter *fp)

{

	atomic_inc(&fp->refcnt);

	atomic_add(sk_filter_size(fp->len), &sk->sk_omem_alloc);

}



static int __sk_prepare_filter(struct sk_filter *fp)

{