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net: filter: move filter accounting to filter core

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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: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann 2014-03-28 18:58:20 +01:00 committed by David S. Miller
parent a3ea269b8b
commit fbc907f0b1
3 changed files with 42 additions and 42 deletions
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30
include/linux/filter.h
View file

@ -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,
const struct sock_filter *filter);
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,
struct sock_fprog *fprog);
extern void sk_unattached_filter_destroy(struct sk_filter *fp);
int sk_unattached_filter_create(struct sk_filter **pfp,
struct sock_fprog *fprog);
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)

27
include/net/sock.h
View file

@ -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.
*

27
net/core/filter.c
View file

@ -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)
{