#ifndef __LINUX_NETFILTER_H #define __LINUX_NETFILTER_H #ifdef __KERNEL__ #include <linux/init.h> #include <linux/skbuff.h> #include <linux/net.h> #include <linux/if.h> #include <linux/in.h> #include <linux/in6.h> #include <linux/wait.h> #include <linux/list.h> #endif #include <linux/types.h> #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 or errno values. Not nice, but better than additional function * arguments. */ #define NF_VERDICT_MASK 0x000000ff /* extra verdict flags have mask 0x0000ff00 */ #define NF_VERDICT_FLAG_QUEUE_BYPASS 0x00008000 /* queue number (NF_QUEUE) or errno (NF_DROP) */ #define NF_VERDICT_QMASK 0xffff0000 #define NF_VERDICT_QBITS 16 #define NF_QUEUE_NR(x) ((((x) << 16) & NF_VERDICT_QMASK) | NF_QUEUE) #define NF_DROP_ERR(x) (((-x) << 16) | NF_DROP) /* 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 /* NF_VERDICT_BITS should be 8 now, but userspace might break if this changes */ #define NF_VERDICT_BITS 16 #endif 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 }; enum { NFPROTO_UNSPEC = 0, NFPROTO_IPV4 = 2, NFPROTO_ARP = 3, NFPROTO_BRIDGE = 7, NFPROTO_IPV6 = 10, NFPROTO_DECNET = 12, NFPROTO_NUMPROTO, }; union nf_inet_addr { __u32 all[4]; __be32 ip; __be32 ip6[4]; struct in_addr in; struct in6_addr in6; }; #ifdef __KERNEL__ #ifdef CONFIG_NETFILTER static inline int NF_DROP_GETERR(int verdict) { return -(verdict >> NF_VERDICT_QBITS); } 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]; } extern void netfilter_init(void); /* Largest hook number + 1 */ #define NF_MAX_HOOKS 8 struct sk_buff; 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; u_int8_t pf; unsigned int hooknum; /* Hooks are ordered in ascending priority. */ int priority; }; struct nf_sockopt_ops { struct list_head list; u_int8_t 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); #ifdef CONFIG_COMPAT int (*compat_set)(struct sock *sk, int optval, void __user *user, unsigned int len); #endif int get_optmin; int get_optmax; int (*get)(struct sock *sk, int optval, void __user *user, int *len); #ifdef CONFIG_COMPAT int (*compat_get)(struct sock *sk, int optval, void __user *user, int *len); #endif /* Use the module struct to lock set/get code in place */ struct module *owner; }; /* 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 */ extern struct ctl_path nf_net_netfilter_sysctl_path[]; extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[]; #endif /* CONFIG_SYSCTL */ extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 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(u_int8_t pf, unsigned int hook, struct sk_buff *skb, struct net_device *indev, struct net_device *outdev, int (*okfn)(struct sk_buff *), int thresh) { #ifndef CONFIG_NETFILTER_DEBUG if (list_empty(&nf_hooks[pf][hook])) return 1; #endif return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh); } static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, struct net_device *indev, struct net_device *outdev, int (*okfn)(struct sk_buff *)) { return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN); } /* 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 :) */ 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; } 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) { int ret; if (!cond || ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1)) ret = okfn(skb); return ret; } 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); } /* Call setsockopt() */ int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, unsigned int len); int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, int *len); #ifdef CONFIG_COMPAT int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, unsigned int len); int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, int *len); #endif /* 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 *skb, unsigned int writable_len); struct flowi; struct nf_queue_entry; struct nf_afinfo { unsigned short family; __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, u_int8_t protocol); __sum16 (*checksum_partial)(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, unsigned int len, u_int8_t protocol); int (*route)(struct net *net, struct dst_entry **dst, struct flowi *fl, bool strict); void (*saveroute)(const struct sk_buff *skb, struct nf_queue_entry *entry); int (*reroute)(struct sk_buff *skb, const struct nf_queue_entry *entry); int route_key_size; }; extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO]; static inline const 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) { const 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; } 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; } extern int nf_register_afinfo(const struct nf_afinfo *afinfo); extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo); #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, u_int8_t family) { #ifdef CONFIG_NF_NAT_NEEDED void (*decodefn)(struct sk_buff *, struct flowi *); if (family == AF_INET) { rcu_read_lock(); decodefn = rcu_dereference(ip_nat_decode_session); if (decodefn) decodefn(skb, fl); rcu_read_unlock(); } #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(u_int8_t pf, unsigned int hook, struct sk_buff *skb, struct net_device *indev, struct net_device *outdev, int (*okfn)(struct sk_buff *), int thresh) { return okfn(skb); } static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb, 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, u_int8_t 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 *) __rcu; extern void nf_ct_attach(struct sk_buff *, struct sk_buff *); extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu; #else static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} #endif #endif /*__KERNEL__*/ #endif /*__LINUX_NETFILTER_H*/