diff options
Diffstat (limited to 'include/linux/netfilter.h')
| -rw-r--r-- | include/linux/netfilter.h | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h new file mode 100644 index 00000000..857f5026 --- /dev/null +++ b/include/linux/netfilter.h @@ -0,0 +1,381 @@ +#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> +#include <linux/sysctl.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*/ |