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kernel/include/linux/netfilter.h
Yasuyuki Kozakai ce7663d84a [NETFILTER]: nfnetlink_queue: don't unregister handler of other subsystem 
The queue handlers registered by ip[6]_queue.ko at initialization should
not be unregistered according to requests from userland program
using nfnetlink_queue. If we allow that, there is no way to register
the handlers of built-in ip[6]_queue again.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-07-10 22:18:21 -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
/* we overload the higher bits for encoding auxiliary data such as the queue
* number. Not nice, but better than additional function arguments. */
#define NF_VERDICT_MASK 0x0000ffff
#define NF_VERDICT_BITS 16
#define NF_VERDICT_QMASK 0xffff0000
#define NF_VERDICT_QBITS 16
#define NF_QUEUE_NR(x) (((x << NF_VERDICT_QBITS) & NF_VERDICT_QMASK) | NF_QUEUE)
/* 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__
#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 (*compat_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);
int (*compat_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);
int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
/* 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);
#ifdef CONFIG_SYSCTL
/* Sysctl registration */
struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path,
struct ctl_table *table);
void nf_unregister_sysctl_table(struct ctl_table_header *header,
struct ctl_table *table);
extern struct ctl_table nf_net_netfilter_sysctl_path[];
extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[];
#endif /* CONFIG_SYSCTL */
extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will
* disappear once iptables is replaced with pkttables. Please DO NOT use them
* for any new code! */
#define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */
#define NF_LOG_TCPOPT 0x02 /* Log TCP options */
#define NF_LOG_IPOPT 0x04 /* Log IP options */
#define NF_LOG_UID 0x08 /* Log UID owning local socket */
#define NF_LOG_MASK 0x0f
#define NF_LOG_TYPE_LOG 0x01
#define NF_LOG_TYPE_ULOG 0x02
struct nf_loginfo {
u_int8_t type;
union {
struct {
u_int32_t copy_len;
u_int16_t group;
u_int16_t qthreshold;
} ulog;
struct {
u_int8_t level;
u_int8_t logflags;
} log;
} u;
};
typedef void nf_logfn(unsigned int pf,
unsigned int hooknum,
const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const struct nf_loginfo *li,
const char *prefix);
struct nf_logger {
struct module *me;
nf_logfn *logfn;
char *name;
};
/* Function to register/unregister log function. */
int nf_log_register(int pf, struct nf_logger *logger);
void nf_log_unregister(struct nf_logger *logger);
void nf_log_unregister_pf(int pf);
/* 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,
struct nf_loginfo *li,
const char *fmt, ...);
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);
/**
* nf_hook_thresh - call a netfilter hook
*
* Returns 1 if the hook has allowed the packet to pass. The function
* okfn must be invoked by the caller in this case. Any other return
* value indicates the packet has been consumed by the hook.
*/
static inline int nf_hook_thresh(int pf, unsigned int hook,
struct sk_buff **pskb,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *), int thresh,
int cond)
{
if (!cond)
return 1;
#ifndef CONFIG_NETFILTER_DEBUG
if (list_empty(&nf_hooks[pf][hook]))
return 1;
#endif
return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh);
}
static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
struct net_device *indev, struct net_device *outdev,
int (*okfn)(struct sk_buff *))
{
return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1);
}
/* 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 */
/* HX: It's slightly less gross now. */
#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
({int __ret; \
if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\
__ret = (okfn)(skb); \
__ret;})
#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \
({int __ret; \
if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
__ret = (okfn)(skb); \
__ret;})
#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
/* 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);
int compat_nf_setsockopt(struct sock *sk, int pf, int optval,
char __user *opt, int len);
int compat_nf_getsockopt(struct sock *sk, int pf, int optval,
char __user *opt, int *len);
/* Packet queuing */
struct nf_queue_handler {
int (*outfn)(struct sk_buff *skb, struct nf_info *info,
unsigned int queuenum, void *data);
void *data;
char *name;
};
extern int nf_register_queue_handler(int pf,
struct nf_queue_handler *qh);
extern int nf_unregister_queue_handler(int pf,
struct nf_queue_handler *qh);
extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh);
extern void nf_reinject(struct sk_buff *skb,
struct nf_info *info,
unsigned int verdict);
/* FIXME: Before cache is ever used, this must be implemented for real. */
extern void nf_invalidate_cache(int pf);
/* Call this before modifying an existing packet: ensures it is
modifiable and linear to the point you care about (writable_len).
Returns true or false. */
extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len);
static inline void nf_csum_replace4(__sum16 *sum, __be32 from, __be32 to)
{
__be32 diff[] = { ~from, to };
*sum = csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum_unfold(*sum)));
}
static inline void nf_csum_replace2(__sum16 *sum, __be16 from, __be16 to)
{
nf_csum_replace4(sum, (__force __be32)from, (__force __be32)to);
}
extern void nf_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
__be32 from, __be32 to, int pseudohdr);
static inline void nf_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
__be16 from, __be16 to, int pseudohdr)
{
nf_proto_csum_replace4(sum, skb, (__force __be32)from,
(__force __be32)to, pseudohdr);
}
struct nf_afinfo {
unsigned short family;
__sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u_int8_t protocol);
void (*saveroute)(const struct sk_buff *skb,
struct nf_info *info);
int (*reroute)(struct sk_buff **skb,
const struct nf_info *info);
int route_key_size;
};
extern struct nf_afinfo *nf_afinfo[];
static inline struct nf_afinfo *nf_get_afinfo(unsigned short family)
{
return rcu_dereference(nf_afinfo[family]);
}
static inline __sum16
nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
u_int8_t protocol, unsigned short family)
{
struct nf_afinfo *afinfo;
__sum16 csum = 0;
rcu_read_lock();
afinfo = nf_get_afinfo(family);
if (afinfo)
csum = afinfo->checksum(skb, hook, dataoff, protocol);
rcu_read_unlock();
return csum;
}
extern int nf_register_afinfo(struct nf_afinfo *afinfo);
extern void nf_unregister_afinfo(struct nf_afinfo *afinfo);
#define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info))
#include <net/flow.h>
extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
static inline void
nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family)
{
#if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED)
void (*decodefn)(struct sk_buff *, struct flowi *);
if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
decodefn(skb, fl);
#endif
}
#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
extern struct proc_dir_entry *proc_net_netfilter;
#endif
#else /* !CONFIG_NETFILTER */
#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
static inline int nf_hook_thresh(int pf, unsigned int hook,
struct sk_buff **pskb,
struct net_device *indev,
struct net_device *outdev,
int (*okfn)(struct sk_buff *), int thresh,
int cond)
{
return okfn(*pskb);
}
static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
struct net_device *indev, struct net_device *outdev,
int (*okfn)(struct sk_buff *))
{
return 1;
}
struct flowi;
static inline void
nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {}
#endif /*CONFIG_NETFILTER*/
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
extern void (*nf_ct_destroy)(struct nf_conntrack *);
#else
static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
#endif
#endif /*__KERNEL__*/
#endif /*__LINUX_NETFILTER_H*/
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