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6869c4d8e0
linux-next/include/linux/netfilter.h
Harald Welte 6869c4d8e0 [NETFILTER]: reduce netfilter sk_buff enlargement 
As discussed at netconf'05, we're trying to save every bit in sk_buff.
The patch below makes sk_buff 8 bytes smaller.  I did some basic
testing on my notebook and it seems to work.

The only real in-tree user of nfcache was IPVS, who only needs a
single bit.  Unfortunately I couldn't find some other free bit in
sk_buff to stuff that bit into, so I introduced a separate field for
them.  Maybe the IPVS guys can resolve that to further save space.

Initially I wanted to shrink pkt_type to three bits (PACKET_HOST and
alike are only 6 values defined), but unfortunately the bluetooth code
overloads pkt_type :(

The conntrack-event-api (out-of-tree) uses nfcache, but Rusty just
came up with a way how to do it without any skb fields, so it's safe
to remove it.

- remove all never-implemented 'nfcache' code
- don't have ipvs code abuse 'nfcache' field. currently get's their own
  compile-conditional skb->ipvs_property field.  IPVS maintainers can
  decide to move this bit elswhere, but nfcache needs to die.
- remove skb->nfcache field to save 4 bytes
- move skb->nfctinfo into three unused bits to save further 4 bytes

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-08-29 15:31:04 -07:00

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#ifndef __LINUX_NETFILTER_H
#define __LINUX_NETFILTER_H
#ifdef __KERNEL__
#include <linux/init.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/net.h>
#include <linux/if.h>
#include <linux/wait.h>
#include <linux/list.h>
#endif
#include <linux/compiler.h>
/* Responses from hook functions. */
#define NF_DROP 0
#define NF_ACCEPT 1
#define NF_STOLEN 2
#define NF_QUEUE 3
#define NF_REPEAT 4
#define NF_STOP 5
#define NF_MAX_VERDICT NF_STOP
/* only for userspace compatibility */
#ifndef __KERNEL__
/* Generic cache responses from hook functions.
<= 0x2000 is used for protocol-flags. */
#define NFC_UNKNOWN 0x4000
#define NFC_ALTERED 0x8000
#endif
#ifdef __KERNEL__
#include <linux/config.h>
#ifdef CONFIG_NETFILTER
extern void netfilter_init(void);
/* Largest hook number + 1 */
#define NF_MAX_HOOKS 8
struct sk_buff;
struct net_device;
typedef unsigned int nf_hookfn(unsigned int hooknum,
struct sk_buff **skb,
const struct net_device *in,
const struct net_device *out,
int (*okfn)(struct sk_buff *));
struct nf_hook_ops
{
struct list_head list;
/* User fills in from here down. */
nf_hookfn *hook;
struct module *owner;
int pf;
int hooknum;
/* Hooks are ordered in ascending priority. */
int priority;
};
struct nf_sockopt_ops
{
struct list_head list;
int pf;
/* Non-inclusive ranges: use 0/0/NULL to never get called. */
int set_optmin;
int set_optmax;
int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
int get_optmin;
int get_optmax;
int (*get)(struct sock *sk, int optval, void __user *user, int *len);
/* Number of users inside set() or get(). */
unsigned int use;
struct task_struct *cleanup_task;
};
/* Each queued (to userspace) skbuff has one of these. */
struct nf_info
{
/* The ops struct which sent us to userspace. */
struct nf_hook_ops *elem;
/* If we're sent to userspace, this keeps housekeeping info */
int pf;
unsigned int hook;
struct net_device *indev, *outdev;
int (*okfn)(struct sk_buff *);
};
/* Function to register/unregister hook points. */
int nf_register_hook(struct nf_hook_ops *reg);
void nf_unregister_hook(struct nf_hook_ops *reg);
/* Functions to register get/setsockopt ranges (non-inclusive). You
need to check permissions yourself! */
int nf_register_sockopt(struct nf_sockopt_ops *reg);
void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
typedef void nf_logfn(unsigned int hooknum,
const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const char *prefix);
/* Function to register/unregister log function. */
int nf_log_register(int pf, nf_logfn *logfn);
void nf_log_unregister(int pf, nf_logfn *logfn);
/* Calls the registered backend logging function */
void nf_log_packet(int pf,
unsigned int hooknum,
const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const char *fmt, ...);
/* Activate hook; either okfn or kfree_skb called, unless a hook
returns NF_STOLEN (in which case, it's up to the hook to deal with
the consequences).
Returns -ERRNO if packet dropped. Zero means queued, stolen or
accepted.
*/
/* RR:
> I don't want nf_hook to return anything because people might forget
> about async and trust the return value to mean "packet was ok".
AK:
Just document it clearly, then you can expect some sense from kernel
coders :)
*/
/* This is gross, but inline doesn't cut it for avoiding the function
call in fast path: gcc doesn't inline (needs value tracking?). --RR */
#ifdef CONFIG_NETFILTER_DEBUG
#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
({int __ret; \
if ((__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, INT_MIN)) == 1) \
__ret = (okfn)(skb); \
__ret;})
#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
({int __ret; \
if ((__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, thresh)) == 1) \
__ret = (okfn)(skb); \
__ret;})
#else
#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
({int __ret; \
if (list_empty(&nf_hooks[pf][hook]) || \
(__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, INT_MIN)) == 1) \
__ret = (okfn)(skb); \
__ret;})
#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
({int __ret; \
if (list_empty(&nf_hooks[pf][hook]) || \
(__ret=nf_hook_slow(pf, hook, &(skb), indev, outdev, okfn, thresh)) == 1) \
__ret = (okfn)(skb); \
__ret;})
#endif
int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
struct net_device *indev, struct net_device *outdev,
int (*okfn)(struct sk_buff *), int thresh);
/* Call setsockopt() */
int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt,
int len);
int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt,
int *len);
/* Packet queuing */
typedef int (*nf_queue_outfn_t)(struct sk_buff *skb,
struct nf_info *info, void *data);
extern int nf_register_queue_handler(int pf,
nf_queue_outfn_t outfn, void *data);
extern int nf_unregister_queue_handler(int pf);
extern void nf_reinject(struct sk_buff *skb,
struct nf_info *info,
unsigned int verdict);
extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
/* FIXME: Before cache is ever used, this must be implemented for real. */
extern void nf_invalidate_cache(int pf);
#else /* !CONFIG_NETFILTER */
#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
#endif /*CONFIG_NETFILTER*/
#endif /*__KERNEL__*/
#endif /*__LINUX_NETFILTER_H*/
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