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