398 lines
11 KiB
C
398 lines
11 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/skbuff.h>
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#include <linux/net.h>
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#include <linux/if.h>
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#include <linux/in.h>
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#include <linux/in6.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/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. */
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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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/* 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
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* arguments. */
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#define NF_VERDICT_MASK 0x000000ff
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/* 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
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#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 */
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#ifndef __KERNEL__
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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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/* NF_VERDICT_BITS should be 8 now, but userspace might break if this changes */
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#define NF_VERDICT_BITS 16
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#endif
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enum nf_inet_hooks {
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NF_INET_PRE_ROUTING,
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NF_INET_LOCAL_IN,
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NF_INET_FORWARD,
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NF_INET_LOCAL_OUT,
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NF_INET_POST_ROUTING,
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NF_INET_NUMHOOKS
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};
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enum {
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NFPROTO_UNSPEC = 0,
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NFPROTO_IPV4 = 2,
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NFPROTO_ARP = 3,
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NFPROTO_BRIDGE = 7,
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NFPROTO_IPV6 = 10,
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NFPROTO_DECNET = 12,
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NFPROTO_NUMPROTO,
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};
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union nf_inet_addr {
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__u32 all[4];
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__be32 ip;
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__be32 ip6[4];
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struct in_addr in;
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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)
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{
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return -(verdict >> NF_VERDICT_QBITS);
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}
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static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
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const union nf_inet_addr *a2)
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{
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return a1->all[0] == a2->all[0] &&
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a1->all[1] == a2->all[1] &&
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a1->all[2] == a2->all[2] &&
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a1->all[3] == a2->all[3];
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}
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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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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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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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u_int8_t pf;
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unsigned 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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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. */
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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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#ifdef CONFIG_COMPAT
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int (*compat_set)(struct sock *sk, int optval,
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void __user *user, unsigned int len);
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#endif
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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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#ifdef CONFIG_COMPAT
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int (*compat_get)(struct sock *sk, int optval,
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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 */
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struct module *owner;
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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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int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
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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
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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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#ifdef CONFIG_SYSCTL
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/* Sysctl registration */
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extern struct ctl_path nf_net_netfilter_sysctl_path[];
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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)
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#include <linux/static_key.h>
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extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
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static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook)
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{
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if (__builtin_constant_p(pf) &&
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__builtin_constant_p(hook))
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return static_key_false(&nf_hooks_needed[pf][hook]);
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return !list_empty(&nf_hooks[pf][hook]);
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}
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#else
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static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook)
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{
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return !list_empty(&nf_hooks[pf][hook]);
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}
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#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,
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int (*okfn)(struct sk_buff *), int thresh);
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/**
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* nf_hook_thresh - call a netfilter hook
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*
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* Returns 1 if the hook has allowed the packet to pass. The function
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* okfn must be invoked by the caller in this case. Any other return
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* value indicates the packet has been consumed by the hook.
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*/
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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,
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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))
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return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
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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,
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int (*okfn)(struct sk_buff *))
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{
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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
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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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static inline int
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NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb,
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struct net_device *in, struct net_device *out,
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int (*okfn)(struct sk_buff *), int thresh)
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{
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int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh);
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if (ret == 1)
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ret = okfn(skb);
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return ret;
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}
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static inline int
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NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb,
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struct net_device *in, struct net_device *out,
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int (*okfn)(struct sk_buff *), bool cond)
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{
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int ret;
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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);
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return ret;
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}
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static inline int
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NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb,
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struct net_device *in, struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN);
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}
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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
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modifiable and linear to the point you care about (writable_len).
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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 {
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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,
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unsigned int hook,
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unsigned int dataoff,
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unsigned int len,
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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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{
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return rcu_dereference(nf_afinfo[family]);
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}
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static inline __sum16
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nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
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u_int8_t protocol, unsigned short family)
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{
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const struct nf_afinfo *afinfo;
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__sum16 csum = 0;
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rcu_read_lock();
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afinfo = nf_get_afinfo(family);
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if (afinfo)
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csum = afinfo->checksum(skb, hook, dataoff, protocol);
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rcu_read_unlock();
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return csum;
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}
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static inline __sum16
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nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
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unsigned int dataoff, unsigned int len,
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u_int8_t protocol, unsigned short family)
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{
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const struct nf_afinfo *afinfo;
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__sum16 csum = 0;
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rcu_read_lock();
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afinfo = nf_get_afinfo(family);
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if (afinfo)
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csum = afinfo->checksum_partial(skb, hook, dataoff, len,
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protocol);
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rcu_read_unlock();
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return csum;
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}
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extern int nf_register_afinfo(const struct nf_afinfo *afinfo);
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extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
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#include <net/flow.h>
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extern void (*ip_nat_decode_session)(struct sk_buff *, 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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{
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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) {
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rcu_read_lock();
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decodefn = rcu_dereference(ip_nat_decode_session);
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if (decodefn)
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decodefn(skb, fl);
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rcu_read_unlock();
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}
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#endif
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}
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#ifdef CONFIG_PROC_FS
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#include <linux/proc_fs.h>
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extern struct proc_dir_entry *proc_net_netfilter;
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#endif
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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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#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,
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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,
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int (*okfn)(struct sk_buff *))
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{
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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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{
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}
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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
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static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
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#endif
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#endif /*__KERNEL__*/
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#endif /*__LINUX_NETFILTER_H*/
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