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include/linux/netfilter.h
10.8 KB
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#ifndef __LINUX_NETFILTER_H #define __LINUX_NETFILTER_H #ifdef __KERNEL__ #include <linux/init.h> |
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#include <linux/skbuff.h> #include <linux/net.h> #include <linux/if.h> |
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#include <linux/in.h> #include <linux/in6.h> |
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#include <linux/wait.h> #include <linux/list.h> #endif |
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#include <linux/types.h> |
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#include <linux/compiler.h> |
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#include <linux/sysctl.h> |
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/* 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 |
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/* we overload the higher bits for encoding auxiliary data such as the queue |
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* number or errno values. Not nice, but better than additional function * arguments. */ #define NF_VERDICT_MASK 0x000000ff /* extra verdict flags have mask 0x0000ff00 */ |
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#define NF_VERDICT_FLAG_QUEUE_BYPASS 0x00008000 |
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/* queue number (NF_QUEUE) or errno (NF_DROP) */ |
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#define NF_VERDICT_QMASK 0xffff0000 #define NF_VERDICT_QBITS 16 |
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#define NF_QUEUE_NR(x) ((((x) << 16) & NF_VERDICT_QMASK) | NF_QUEUE) |
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#define NF_DROP_ERR(x) (((-x) << 16) | NF_DROP) |
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/* only for userspace compatibility */ #ifndef __KERNEL__ |
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/* Generic cache responses from hook functions. <= 0x2000 is used for protocol-flags. */ #define NFC_UNKNOWN 0x4000 #define NFC_ALTERED 0x8000 |
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/* NF_VERDICT_BITS should be 8 now, but userspace might break if this changes */ #define NF_VERDICT_BITS 16 |
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#endif |
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enum nf_inet_hooks { NF_INET_PRE_ROUTING, NF_INET_LOCAL_IN, NF_INET_FORWARD, NF_INET_LOCAL_OUT, NF_INET_POST_ROUTING, NF_INET_NUMHOOKS }; |
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enum { NFPROTO_UNSPEC = 0, NFPROTO_IPV4 = 2, NFPROTO_ARP = 3, NFPROTO_BRIDGE = 7, NFPROTO_IPV6 = 10, NFPROTO_DECNET = 12, NFPROTO_NUMPROTO, }; |
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union nf_inet_addr { |
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__u32 all[4]; |
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__be32 ip; __be32 ip6[4]; |
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struct in_addr in; struct in6_addr in6; |
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}; |
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#ifdef __KERNEL__ |
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#ifdef CONFIG_NETFILTER |
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static inline int NF_DROP_GETERR(int verdict) { return -(verdict >> NF_VERDICT_QBITS); } |
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static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1, const union nf_inet_addr *a2) { return a1->all[0] == a2->all[0] && a1->all[1] == a2->all[1] && a1->all[2] == a2->all[2] && a1->all[3] == a2->all[3]; } |
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extern void netfilter_init(void); /* Largest hook number + 1 */ #define NF_MAX_HOOKS 8 struct sk_buff; |
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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, const struct net_device *out, int (*okfn)(struct sk_buff *)); |
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struct nf_hook_ops { |
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struct list_head list; /* User fills in from here down. */ nf_hookfn *hook; struct module *owner; |
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u_int8_t pf; unsigned int hooknum; |
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/* Hooks are ordered in ascending priority. */ int priority; }; |
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struct nf_sockopt_ops { |
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struct list_head list; |
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u_int8_t pf; |
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/* 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); |
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#ifdef CONFIG_COMPAT |
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int (*compat_set)(struct sock *sk, int optval, void __user *user, unsigned int len); |
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#endif |
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int get_optmin; int get_optmax; int (*get)(struct sock *sk, int optval, void __user *user, int *len); |
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#ifdef CONFIG_COMPAT |
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int (*compat_get)(struct sock *sk, int optval, void __user *user, int *len); |
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#endif |
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/* Use the module struct to lock set/get code in place */ struct module *owner; |
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}; |
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/* Function to register/unregister hook points. */ int nf_register_hook(struct nf_hook_ops *reg); void nf_unregister_hook(struct nf_hook_ops *reg); |
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int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n); void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n); |
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/* 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); |
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#ifdef CONFIG_SYSCTL /* Sysctl registration */ |
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extern struct ctl_path nf_net_netfilter_sysctl_path[]; extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[]; |
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#endif /* CONFIG_SYSCTL */ |
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extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; |
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#if defined(CONFIG_JUMP_LABEL) #include <linux/jump_label.h> extern struct jump_label_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook) { if (__builtin_constant_p(pf) && __builtin_constant_p(hook)) return static_branch(&nf_hooks_needed[pf][hook]); return !list_empty(&nf_hooks[pf][hook]); } #else static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook) { return !list_empty(&nf_hooks[pf][hook]); } #endif |
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int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb, |
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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. */ |
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static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, |
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struct sk_buff *skb, |
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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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{ |
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if (nf_hooks_active(pf, hook)) return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); return 1; |
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} |
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static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, |
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struct net_device *indev, struct net_device *outdev, int (*okfn)(struct sk_buff *)) { |
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return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN); |
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} |
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/* 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 :) */ |
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static inline int NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb, struct net_device *in, struct net_device *out, int (*okfn)(struct sk_buff *), int thresh) { int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh); if (ret == 1) ret = okfn(skb); return ret; } |
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static inline int NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb, struct net_device *in, struct net_device *out, int (*okfn)(struct sk_buff *), bool cond) { |
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int ret; if (!cond || |
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((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1)) |
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ret = okfn(skb); return ret; } |
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static inline int NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb, struct net_device *in, struct net_device *out, int (*okfn)(struct sk_buff *)) { return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN); } |
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/* Call setsockopt() */ |
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int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, |
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unsigned int len); |
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int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, |
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int *len); |
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#ifdef CONFIG_COMPAT |
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int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, |
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char __user *opt, unsigned int len); |
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int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, |
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char __user *opt, int *len); |
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#endif |
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/* 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. */ |
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extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); |
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struct flowi; |
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struct nf_queue_entry; |
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struct nf_afinfo { unsigned short family; |
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__sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, |
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unsigned int dataoff, u_int8_t protocol); |
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__sum16 (*checksum_partial)(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, unsigned int len, u_int8_t protocol); |
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int (*route)(struct net *net, struct dst_entry **dst, |
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struct flowi *fl, bool strict); |
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void (*saveroute)(const struct sk_buff *skb, |
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struct nf_queue_entry *entry); |
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int (*reroute)(struct sk_buff *skb, |
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const struct nf_queue_entry *entry); |
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int route_key_size; |
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}; |
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extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO]; |
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static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family) |
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{ return rcu_dereference(nf_afinfo[family]); } |
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static inline __sum16 |
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nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, u_int8_t protocol, unsigned short family) { |
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const struct nf_afinfo *afinfo; |
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__sum16 csum = 0; |
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rcu_read_lock(); afinfo = nf_get_afinfo(family); if (afinfo) csum = afinfo->checksum(skb, hook, dataoff, protocol); rcu_read_unlock(); return csum; } |
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static inline __sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, unsigned int len, u_int8_t protocol, unsigned short family) { const struct nf_afinfo *afinfo; __sum16 csum = 0; rcu_read_lock(); afinfo = nf_get_afinfo(family); if (afinfo) csum = afinfo->checksum_partial(skb, hook, dataoff, len, protocol); rcu_read_unlock(); return csum; } |
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extern int nf_register_afinfo(const struct nf_afinfo *afinfo); extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo); |
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#include <net/flow.h> extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *); static inline void |
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nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) |
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{ |
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#ifdef CONFIG_NF_NAT_NEEDED |
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void (*decodefn)(struct sk_buff *, struct flowi *); |
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if (family == AF_INET) { rcu_read_lock(); decodefn = rcu_dereference(ip_nat_decode_session); if (decodefn) decodefn(skb, fl); rcu_read_unlock(); } |
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#endif } |
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#ifdef CONFIG_PROC_FS #include <linux/proc_fs.h> extern struct proc_dir_entry *proc_net_netfilter; #endif |
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#else /* !CONFIG_NETFILTER */ #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb) |
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#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb) |
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static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook, |
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struct sk_buff *skb, |
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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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{ |
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return okfn(skb); |
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} |
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static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, |
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struct net_device *indev, struct net_device *outdev, int (*okfn)(struct sk_buff *)) { |
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return 1; |
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} |
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struct flowi; |
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static inline void |
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nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) { } |
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#endif /*CONFIG_NETFILTER*/ |
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) |
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extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *) __rcu; |
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extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); |
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extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu; |
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#else static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} #endif |
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#endif /*__KERNEL__*/ #endif /*__LINUX_NETFILTER_H*/ |