forked from mirrors/linux
9c92d34864
nf_hook() is supposed to call the netfilter hook and return control of the packet back to the caller in case it may pass, the okfn is only used for queueing. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
330 lines
9.4 KiB
C
330 lines
9.4 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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/* we overload the higher bits for encoding auxiliary data such as the queue
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* number. Not nice, but better than additional function arguments. */
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#define NF_VERDICT_MASK 0x0000ffff
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#define NF_VERDICT_BITS 16
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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 << NF_VERDICT_QBITS) & NF_VERDICT_QMASK) | NF_QUEUE)
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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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#endif
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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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/* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will
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* disappear once iptables is replaced with pkttables. Please DO NOT use them
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* for any new code! */
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#define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */
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#define NF_LOG_TCPOPT 0x02 /* Log TCP options */
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#define NF_LOG_IPOPT 0x04 /* Log IP options */
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#define NF_LOG_UID 0x08 /* Log UID owning local socket */
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#define NF_LOG_MASK 0x0f
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#define NF_LOG_TYPE_LOG 0x01
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#define NF_LOG_TYPE_ULOG 0x02
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struct nf_loginfo {
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u_int8_t type;
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union {
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struct {
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u_int32_t copy_len;
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u_int16_t group;
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u_int16_t qthreshold;
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} ulog;
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struct {
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u_int8_t level;
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u_int8_t logflags;
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} log;
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} u;
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};
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typedef void nf_logfn(unsigned 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 struct nf_loginfo *li,
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const char *prefix);
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struct nf_logger {
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struct module *me;
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nf_logfn *logfn;
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char *name;
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};
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/* Function to register/unregister log function. */
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int nf_log_register(int pf, struct nf_logger *logger);
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int nf_log_unregister_pf(int pf);
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void nf_log_unregister_logger(struct nf_logger *logger);
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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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struct nf_loginfo *li,
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const char *fmt, ...);
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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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/**
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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(int pf, unsigned int hook,
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struct sk_buff **pskb,
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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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int cond)
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{
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if (!cond)
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return 1;
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#ifndef CONFIG_NETFILTER_DEBUG
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if (list_empty(&nf_hooks[pf][hook]))
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return 1;
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#endif
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return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh);
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}
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static inline int nf_hook(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 *))
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{
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return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1);
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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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/* 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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/* HX: It's slightly less gross now. */
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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_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\
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__ret = (okfn)(skb); \
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__ret;})
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#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \
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({int __ret; \
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if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
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__ret = (okfn)(skb); \
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__ret;})
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#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
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NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
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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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struct nf_queue_handler {
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int (*outfn)(struct sk_buff *skb, struct nf_info *info,
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unsigned int queuenum, void *data);
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void *data;
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char *name;
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};
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extern int nf_register_queue_handler(int pf,
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struct nf_queue_handler *qh);
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extern int nf_unregister_queue_handler(int pf);
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extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh);
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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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/* 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 **pskb, unsigned int writable_len);
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struct nf_queue_rerouter {
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void (*save)(const struct sk_buff *skb, struct nf_info *info);
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int (*reroute)(struct sk_buff **skb, const struct nf_info *info);
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int rer_size;
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};
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#define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info))
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extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer);
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extern int nf_unregister_queue_rerouter(int pf);
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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, int family)
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{
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#ifdef CONFIG_IP_NF_NAT_NEEDED
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void (*decodefn)(struct sk_buff *, struct flowi *);
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if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
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decodefn(skb, fl);
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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(int pf, unsigned int hook,
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struct sk_buff **pskb,
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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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int cond)
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{
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return okfn(*pskb);
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}
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static inline int nf_hook(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 *))
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{
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return 1;
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}
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static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
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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, int family) {}
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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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