netfilter: x_table: speedup compat operations

[linux-2.6/btrfs-unstable.git] / include / linux / netfilter / x_tables.h

#ifndef _X_TABLES_H
#define _X_TABLES_H
#include <linux/kernel.h>
#include <linux/types.h>

#define XT_FUNCTION_MAXNAMELEN 30
#define XT_EXTENSION_MAXNAMELEN 29
#define XT_TABLE_MAXNAMELEN 32

struct xt_entry_match {
        union {
                struct {
                        __u16 match_size;

                        /* Used by userspace */
                        char name[XT_EXTENSION_MAXNAMELEN];
                        __u8 revision;
                } user;
                struct {
                        __u16 match_size;

                        /* Used inside the kernel */
                        struct xt_match *match;
                } kernel;

                /* Total length */
                __u16 match_size;
        } u;

        unsigned char data[0];
};

struct xt_entry_target {
        union {
                struct {
                        __u16 target_size;

                        /* Used by userspace */
                        char name[XT_EXTENSION_MAXNAMELEN];
                        __u8 revision;
                } user;
                struct {
                        __u16 target_size;

                        /* Used inside the kernel */
                        struct xt_target *target;
                } kernel;

                /* Total length */
                __u16 target_size;
        } u;

        unsigned char data[0];
};

#define XT_TARGET_INIT(__name, __size)                                         \
{                                                                              \
        .target.u.user = {                                                     \
                .target_size    = XT_ALIGN(__size),                            \
                .name           = __name,                                      \
        },                                                                     \
}

struct xt_standard_target {
        struct xt_entry_target target;
        int verdict;
};

struct xt_error_target {
        struct xt_entry_target target;
        char errorname[XT_FUNCTION_MAXNAMELEN];
};

/* The argument to IPT_SO_GET_REVISION_*.  Returns highest revision
 * kernel supports, if >= revision. */
struct xt_get_revision {
        char name[XT_EXTENSION_MAXNAMELEN];
        __u8 revision;
};

/* CONTINUE verdict for targets */
#define XT_CONTINUE 0xFFFFFFFF

/* For standard target */
#define XT_RETURN (-NF_REPEAT - 1)

/* this is a dummy structure to find out the alignment requirement for a struct
 * containing all the fundamental data types that are used in ipt_entry,
 * ip6t_entry and arpt_entry.  This sucks, and it is a hack.  It will be my
 * personal pleasure to remove it -HW
 */
struct _xt_align {
        __u8 u8;
        __u16 u16;
        __u32 u32;
        __u64 u64;
};

#define XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _xt_align))

/* Standard return verdict, or do jump. */
#define XT_STANDARD_TARGET ""
/* Error verdict. */
#define XT_ERROR_TARGET "ERROR"

#define SET_COUNTER(c,b,p) do { (c).bcnt = (b); (c).pcnt = (p); } while(0)
#define ADD_COUNTER(c,b,p) do { (c).bcnt += (b); (c).pcnt += (p); } while(0)

struct xt_counters {
        __u64 pcnt, bcnt;                       /* Packet and byte counters */
};

/* The argument to IPT_SO_ADD_COUNTERS. */
struct xt_counters_info {
        /* Which table. */
        char name[XT_TABLE_MAXNAMELEN];

        unsigned int num_counters;

        /* The counters (actually `number' of these). */
        struct xt_counters counters[0];
};

#define XT_INV_PROTO            0x40    /* Invert the sense of PROTO. */

#ifndef __KERNEL__
/* fn returns 0 to continue iteration */
#define XT_MATCH_ITERATE(type, e, fn, args...)                  \
({                                                              \
        unsigned int __i;                                       \
        int __ret = 0;                                          \
        struct xt_entry_match *__m;                             \
                                                                \
        for (__i = sizeof(type);                                \
             __i < (e)->target_offset;                          \
             __i += __m->u.match_size) {                        \
                __m = (void *)e + __i;                          \
                                                                \
                __ret = fn(__m , ## args);                      \
                if (__ret != 0)                                 \
                        break;                                  \
        }                                                       \
        __ret;                                                  \
})

/* fn returns 0 to continue iteration */
#define XT_ENTRY_ITERATE_CONTINUE(type, entries, size, n, fn, args...) \
({                                                              \
        unsigned int __i, __n;                                  \
        int __ret = 0;                                          \
        type *__entry;                                          \
                                                                \
        for (__i = 0, __n = 0; __i < (size);                    \
             __i += __entry->next_offset, __n++) {              \
                __entry = (void *)(entries) + __i;              \
                if (__n < n)                                    \
                        continue;                               \
                                                                \
                __ret = fn(__entry , ## args);                  \
                if (__ret != 0)                                 \
                        break;                                  \
        }                                                       \
        __ret;                                                  \
})

/* fn returns 0 to continue iteration */
#define XT_ENTRY_ITERATE(type, entries, size, fn, args...) \
        XT_ENTRY_ITERATE_CONTINUE(type, entries, size, 0, fn, args)

#endif /* !__KERNEL__ */

/* pos is normally a struct ipt_entry/ip6t_entry/etc. */
#define xt_entry_foreach(pos, ehead, esize) \
        for ((pos) = (typeof(pos))(ehead); \
             (pos) < (typeof(pos))((char *)(ehead) + (esize)); \
             (pos) = (typeof(pos))((char *)(pos) + (pos)->next_offset))

/* can only be xt_entry_match, so no use of typeof here */
#define xt_ematch_foreach(pos, entry) \
        for ((pos) = (struct xt_entry_match *)entry->elems; \
             (pos) < (struct xt_entry_match *)((char *)(entry) + \
                     (entry)->target_offset); \
             (pos) = (struct xt_entry_match *)((char *)(pos) + \
                     (pos)->u.match_size))

#ifdef __KERNEL__

#include <linux/netdevice.h>

/**
 * struct xt_action_param - parameters for matches/targets
 *
 * @match:      the match extension
 * @target:     the target extension
 * @matchinfo:  per-match data
 * @targetinfo: per-target data
 * @in:         input netdevice
 * @out:        output netdevice
 * @fragoff:    packet is a fragment, this is the data offset
 * @thoff:      position of transport header relative to skb->data
 * @hook:       hook number given packet came from
 * @family:     Actual NFPROTO_* through which the function is invoked
 *              (helpful when match->family == NFPROTO_UNSPEC)
 *
 * Fields written to by extensions:
 *
 * @hotdrop:    drop packet if we had inspection problems
 * Network namespace obtainable using dev_net(in/out)
 */
struct xt_action_param {
        union {
                const struct xt_match *match;
                const struct xt_target *target;
        };
        union {
                const void *matchinfo, *targinfo;
        };
        const struct net_device *in, *out;
        int fragoff;
        unsigned int thoff;
        unsigned int hooknum;
        u_int8_t family;
        bool hotdrop;
};

/**
 * struct xt_mtchk_param - parameters for match extensions'
 * checkentry functions
 *
 * @net:        network namespace through which the check was invoked
 * @table:      table the rule is tried to be inserted into
 * @entryinfo:  the family-specific rule data
 *              (struct ipt_ip, ip6t_ip, arpt_arp or (note) ebt_entry)
 * @match:      struct xt_match through which this function was invoked
 * @matchinfo:  per-match data
 * @hook_mask:  via which hooks the new rule is reachable
 * Other fields as above.
 */
struct xt_mtchk_param {
        struct net *net;
        const char *table;
        const void *entryinfo;
        const struct xt_match *match;
        void *matchinfo;
        unsigned int hook_mask;
        u_int8_t family;
};

/**
 * struct xt_mdtor_param - match destructor parameters
 * Fields as above.
 */
struct xt_mtdtor_param {
        struct net *net;
        const struct xt_match *match;
        void *matchinfo;
        u_int8_t family;
};

/**
 * struct xt_tgchk_param - parameters for target extensions'
 * checkentry functions
 *
 * @entryinfo:  the family-specific rule data
 *              (struct ipt_entry, ip6t_entry, arpt_entry, ebt_entry)
 *
 * Other fields see above.
 */
struct xt_tgchk_param {
        struct net *net;
        const char *table;
        const void *entryinfo;
        const struct xt_target *target;
        void *targinfo;
        unsigned int hook_mask;
        u_int8_t family;
};

/* Target destructor parameters */
struct xt_tgdtor_param {
        struct net *net;
        const struct xt_target *target;
        void *targinfo;
        u_int8_t family;
};

struct xt_match {
        struct list_head list;

        const char name[XT_EXTENSION_MAXNAMELEN];
        u_int8_t revision;

        /* Return true or false: return FALSE and set *hotdrop = 1 to
           force immediate packet drop. */
        /* Arguments changed since 2.6.9, as this must now handle
           non-linear skb, using skb_header_pointer and
           skb_ip_make_writable. */
        bool (*match)(const struct sk_buff *skb,
                      struct xt_action_param *);

        /* Called when user tries to insert an entry of this type. */
        int (*checkentry)(const struct xt_mtchk_param *);

        /* Called when entry of this type deleted. */
        void (*destroy)(const struct xt_mtdtor_param *);
#ifdef CONFIG_COMPAT
        /* Called when userspace align differs from kernel space one */
        void (*compat_from_user)(void *dst, const void *src);
        int (*compat_to_user)(void __user *dst, const void *src);
#endif
        /* Set this to THIS_MODULE if you are a module, otherwise NULL */
        struct module *me;

        const char *table;
        unsigned int matchsize;
#ifdef CONFIG_COMPAT
        unsigned int compatsize;
#endif
        unsigned int hooks;
        unsigned short proto;

        unsigned short family;
};

/* Registration hooks for targets. */
struct xt_target {
        struct list_head list;

        const char name[XT_EXTENSION_MAXNAMELEN];
        u_int8_t revision;

        /* Returns verdict. Argument order changed since 2.6.9, as this
           must now handle non-linear skbs, using skb_copy_bits and
           skb_ip_make_writable. */
        unsigned int (*target)(struct sk_buff *skb,
                               const struct xt_action_param *);

        /* Called when user tries to insert an entry of this type:
           hook_mask is a bitmask of hooks from which it can be
           called. */
        /* Should return 0 on success or an error code otherwise (-Exxxx). */
        int (*checkentry)(const struct xt_tgchk_param *);

        /* Called when entry of this type deleted. */
        void (*destroy)(const struct xt_tgdtor_param *);
#ifdef CONFIG_COMPAT
        /* Called when userspace align differs from kernel space one */
        void (*compat_from_user)(void *dst, const void *src);
        int (*compat_to_user)(void __user *dst, const void *src);
#endif
        /* Set this to THIS_MODULE if you are a module, otherwise NULL */
        struct module *me;

        const char *table;
        unsigned int targetsize;
#ifdef CONFIG_COMPAT
        unsigned int compatsize;
#endif
        unsigned int hooks;
        unsigned short proto;

        unsigned short family;
};

/* Furniture shopping... */
struct xt_table {
        struct list_head list;

        /* What hooks you will enter on */
        unsigned int valid_hooks;

        /* Man behind the curtain... */
        struct xt_table_info *private;

        /* Set this to THIS_MODULE if you are a module, otherwise NULL */
        struct module *me;

        u_int8_t af;            /* address/protocol family */
        int priority;           /* hook order */

        /* A unique name... */
        const char name[XT_TABLE_MAXNAMELEN];
};

#include <linux/netfilter_ipv4.h>

/* The table itself */
struct xt_table_info {
        /* Size per table */
        unsigned int size;
        /* Number of entries: FIXME. --RR */
        unsigned int number;
        /* Initial number of entries. Needed for module usage count */
        unsigned int initial_entries;

        /* Entry points and underflows */
        unsigned int hook_entry[NF_INET_NUMHOOKS];
        unsigned int underflow[NF_INET_NUMHOOKS];

        /*
         * Number of user chains. Since tables cannot have loops, at most
         * @stacksize jumps (number of user chains) can possibly be made.
         */
        unsigned int stacksize;
        unsigned int __percpu *stackptr;
        void ***jumpstack;
        /* ipt_entry tables: one per CPU */
        /* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
        void *entries[1];
};

#define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
                          + nr_cpu_ids * sizeof(char *))
extern int xt_register_target(struct xt_target *target);
extern void xt_unregister_target(struct xt_target *target);
extern int xt_register_targets(struct xt_target *target, unsigned int n);
extern void xt_unregister_targets(struct xt_target *target, unsigned int n);

extern int xt_register_match(struct xt_match *target);
extern void xt_unregister_match(struct xt_match *target);
extern int xt_register_matches(struct xt_match *match, unsigned int n);
extern void xt_unregister_matches(struct xt_match *match, unsigned int n);

extern int xt_check_match(struct xt_mtchk_param *,
                          unsigned int size, u_int8_t proto, bool inv_proto);
extern int xt_check_target(struct xt_tgchk_param *,
                           unsigned int size, u_int8_t proto, bool inv_proto);

extern struct xt_table *xt_register_table(struct net *net,
                                          const struct xt_table *table,
                                          struct xt_table_info *bootstrap,
                                          struct xt_table_info *newinfo);
extern void *xt_unregister_table(struct xt_table *table);

extern struct xt_table_info *xt_replace_table(struct xt_table *table,
                                              unsigned int num_counters,
                                              struct xt_table_info *newinfo,
                                              int *error);

extern struct xt_match *xt_find_match(u8 af, const char *name, u8 revision);
extern struct xt_target *xt_find_target(u8 af, const char *name, u8 revision);
extern struct xt_match *xt_request_find_match(u8 af, const char *name,
                                              u8 revision);
extern struct xt_target *xt_request_find_target(u8 af, const char *name,
                                                u8 revision);
extern int xt_find_revision(u8 af, const char *name, u8 revision,
                            int target, int *err);

extern struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
                                           const char *name);
extern void xt_table_unlock(struct xt_table *t);

extern int xt_proto_init(struct net *net, u_int8_t af);
extern void xt_proto_fini(struct net *net, u_int8_t af);

extern struct xt_table_info *xt_alloc_table_info(unsigned int size);
extern void xt_free_table_info(struct xt_table_info *info);

/*
 * Per-CPU spinlock associated with per-cpu table entries, and
 * with a counter for the "reading" side that allows a recursive
 * reader to avoid taking the lock and deadlocking.
 *
 * "reading" is used by ip/arp/ip6 tables rule processing which runs per-cpu.
 * It needs to ensure that the rules are not being changed while the packet
 * is being processed. In some cases, the read lock will be acquired
 * twice on the same CPU; this is okay because of the count.
 *
 * "writing" is used when reading counters.
 *  During replace any readers that are using the old tables have to complete
 *  before freeing the old table. This is handled by the write locking
 *  necessary for reading the counters.
 */
struct xt_info_lock {
        spinlock_t lock;
        unsigned char readers;
};
DECLARE_PER_CPU(struct xt_info_lock, xt_info_locks);

/*
 * Note: we need to ensure that preemption is disabled before acquiring
 * the per-cpu-variable, so we do it as a two step process rather than
 * using "spin_lock_bh()".
 *
 * We _also_ need to disable bottom half processing before updating our
 * nesting count, to make sure that the only kind of re-entrancy is this
 * code being called by itself: since the count+lock is not an atomic
 * operation, we can allow no races.
 *
 * _Only_ that special combination of being per-cpu and never getting
 * re-entered asynchronously means that the count is safe.
 */
static inline void xt_info_rdlock_bh(void)
{
        struct xt_info_lock *lock;

        local_bh_disable();
        lock = &__get_cpu_var(xt_info_locks);
        if (likely(!lock->readers++))
                spin_lock(&lock->lock);
}

static inline void xt_info_rdunlock_bh(void)
{
        struct xt_info_lock *lock = &__get_cpu_var(xt_info_locks);

        if (likely(!--lock->readers))
                spin_unlock(&lock->lock);
        local_bh_enable();
}

/*
 * The "writer" side needs to get exclusive access to the lock,
 * regardless of readers.  This must be called with bottom half
 * processing (and thus also preemption) disabled.
 */
static inline void xt_info_wrlock(unsigned int cpu)
{
        spin_lock(&per_cpu(xt_info_locks, cpu).lock);
}

static inline void xt_info_wrunlock(unsigned int cpu)
{
        spin_unlock(&per_cpu(xt_info_locks, cpu).lock);
}

/*
 * This helper is performance critical and must be inlined
 */
static inline unsigned long ifname_compare_aligned(const char *_a,
                                                   const char *_b,
                                                   const char *_mask)
{
        const unsigned long *a = (const unsigned long *)_a;
        const unsigned long *b = (const unsigned long *)_b;
        const unsigned long *mask = (const unsigned long *)_mask;
        unsigned long ret;

        ret = (a[0] ^ b[0]) & mask[0];
        if (IFNAMSIZ > sizeof(unsigned long))
                ret |= (a[1] ^ b[1]) & mask[1];
        if (IFNAMSIZ > 2 * sizeof(unsigned long))
                ret |= (a[2] ^ b[2]) & mask[2];
        if (IFNAMSIZ > 3 * sizeof(unsigned long))
                ret |= (a[3] ^ b[3]) & mask[3];
        BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
        return ret;
}

extern struct nf_hook_ops *xt_hook_link(const struct xt_table *, nf_hookfn *);
extern void xt_hook_unlink(const struct xt_table *, struct nf_hook_ops *);

#ifdef CONFIG_COMPAT
#include <net/compat.h>

struct compat_xt_entry_match {
        union {
                struct {
                        u_int16_t match_size;
                        char name[XT_FUNCTION_MAXNAMELEN - 1];
                        u_int8_t revision;
                } user;
                struct {
                        u_int16_t match_size;
                        compat_uptr_t match;
                } kernel;
                u_int16_t match_size;
        } u;
        unsigned char data[0];
};

struct compat_xt_entry_target {
        union {
                struct {
                        u_int16_t target_size;
                        char name[XT_FUNCTION_MAXNAMELEN - 1];
                        u_int8_t revision;
                } user;
                struct {
                        u_int16_t target_size;
                        compat_uptr_t target;
                } kernel;
                u_int16_t target_size;
        } u;
        unsigned char data[0];
};

/* FIXME: this works only on 32 bit tasks
 * need to change whole approach in order to calculate align as function of
 * current task alignment */

struct compat_xt_counters {
        compat_u64 pcnt, bcnt;                  /* Packet and byte counters */
};

struct compat_xt_counters_info {
        char name[XT_TABLE_MAXNAMELEN];
        compat_uint_t num_counters;
        struct compat_xt_counters counters[0];
};

struct _compat_xt_align {
        __u8 u8;
        __u16 u16;
        __u32 u32;
        compat_u64 u64;
};

#define COMPAT_XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _compat_xt_align))

extern void xt_compat_lock(u_int8_t af);
extern void xt_compat_unlock(u_int8_t af);

extern int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta);
extern void xt_compat_flush_offsets(u_int8_t af);
extern void xt_compat_init_offsets(u_int8_t af, unsigned int number);
extern int xt_compat_calc_jump(u_int8_t af, unsigned int offset);

extern int xt_compat_match_offset(const struct xt_match *match);
extern int xt_compat_match_from_user(struct xt_entry_match *m,
                                     void **dstptr, unsigned int *size);
extern int xt_compat_match_to_user(const struct xt_entry_match *m,
                                   void __user **dstptr, unsigned int *size);

extern int xt_compat_target_offset(const struct xt_target *target);
extern void xt_compat_target_from_user(struct xt_entry_target *t,
                                       void **dstptr, unsigned int *size);
extern int xt_compat_target_to_user(const struct xt_entry_target *t,
                                    void __user **dstptr, unsigned int *size);

#endif /* CONFIG_COMPAT */
#endif /* __KERNEL__ */

#endif /* _X_TABLES_H */