Release 4.11 net/netfilter/x_tables.c

/*
 * x_tables core - Backend for {ip,ip6,arp}_tables
 *
 * Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org>
 * Copyright (C) 2006-2012 Patrick McHardy <kaber@trash.net>
 *
 * Based on existing ip_tables code which is
 *   Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
 *   Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/net.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <linux/mutex.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/audit.h>
#include <linux/user_namespace.h>
#include <net/net_namespace.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_arp.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter_arp/arp_tables.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");


#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))

#define XT_PCPU_BLOCK_SIZE 4096


struct compat_delta {
	
unsigned int offset; /* offset in kernel */
	
int delta; /* delta in 32bit user land */
};


struct xt_af {
	
struct mutex mutex;
	
struct list_head match;
	
struct list_head target;
#ifdef CONFIG_COMPAT
	
struct mutex compat_mutex;
	
struct compat_delta *compat_tab;
	
unsigned int number; /* number of slots in compat_tab[] */
	
unsigned int cur; /* number of used slots in compat_tab[] */
#endif
};


static struct xt_af *xt;


static const char *const xt_prefix[NFPROTO_NUMPROTO] = {
	[NFPROTO_UNSPEC] = "x",
	[NFPROTO_IPV4]   = "ip",
	[NFPROTO_ARP]    = "arp",
	[NFPROTO_BRIDGE] = "eb",
	[NFPROTO_IPV6]   = "ip6",
};

/* Registration hooks for targets. */


int xt_register_target(struct xt_target *target)
{
	u_int8_t af = target->family;

	mutex_lock(&xt[af].mutex);
	list_add(&target->list, &xt[af].target);
	mutex_unlock(&xt[af].mutex);
	return 0;
}
Contributors
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Harald Welte
48
82.76%
1
20.00%
Pablo Neira Ayuso
8
13.79%
2
40.00%
Ingo Molnar
1
1.72%
1
20.00%
Jan Engelhardt
1
1.72%
1
20.00%
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58
100.00%
5
100.00%


EXPORT_SYMBOL(xt_register_target);


void

xt_unregister_target(struct xt_target *target)
{
	u_int8_t af = target->family;

	mutex_lock(&xt[af].mutex);
	list_del(&target->list);
	mutex_unlock(&xt[af].mutex);
}
Contributors
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Harald Welte
35
74.47%
1
20.00%
Pablo Neira Ayuso
6
12.77%
1
20.00%
Patrick McHardy
3
6.38%
1
20.00%
Ingo Molnar
2
4.26%
1
20.00%
Jan Engelhardt
1
2.13%
1
20.00%
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47
100.00%
5
100.00%


EXPORT_SYMBOL(xt_unregister_target);


int

xt_register_targets(struct xt_target *target, unsigned int n)
{
	unsigned int i;
	int err = 0;

	for (i = 0; i < n; i++) {
		err = xt_register_target(&target[i]);
		if (err)
			goto err;
	}
	return err;

err:
	if (i > 0)
		xt_unregister_targets(target, i);
	return err;
}
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Patrick McHardy
76
98.70%
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Harald Welte
1
1.30%
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EXPORT_SYMBOL(xt_register_targets);


void

xt_unregister_targets(struct xt_target *target, unsigned int n)
{
	while (n-- > 0)
		xt_unregister_target(&target[n]);
}
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Patrick McHardy
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7
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EXPORT_SYMBOL(xt_unregister_targets);



int xt_register_match(struct xt_match *match)
{
	u_int8_t af = match->family;

	mutex_lock(&xt[af].mutex);
	list_add(&match->list, &xt[af].match);
	mutex_unlock(&xt[af].mutex);
	return 0;
}
Contributors
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Harald Welte
48
82.76%
1
20.00%
Pablo Neira Ayuso
8
13.79%
2
40.00%
Ingo Molnar
1
1.72%
1
20.00%
Jan Engelhardt
1
1.72%
1
20.00%
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58
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5
100.00%


EXPORT_SYMBOL(xt_register_match);


void

xt_unregister_match(struct xt_match *match)
{
	u_int8_t af = match->family;

	mutex_lock(&xt[af].mutex);
	list_del(&match->list);
	mutex_unlock(&xt[af].mutex);
}
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Harald Welte
35
74.47%
1
20.00%
Pablo Neira Ayuso
6
12.77%
1
20.00%
Patrick McHardy
3
6.38%
1
20.00%
Ingo Molnar
2
4.26%
1
20.00%
Jan Engelhardt
1
2.13%
1
20.00%
Total
47
100.00%
5
100.00%


EXPORT_SYMBOL(xt_unregister_match);


int

xt_register_matches(struct xt_match *match, unsigned int n)
{
	unsigned int i;
	int err = 0;

	for (i = 0; i < n; i++) {
		err = xt_register_match(&match[i]);
		if (err)
			goto err;
	}
	return err;

err:
	if (i > 0)
		xt_unregister_matches(match, i);
	return err;
}
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EXPORT_SYMBOL(xt_register_matches);


void

xt_unregister_matches(struct xt_match *match, unsigned int n)
{
	while (n-- > 0)
		xt_unregister_match(&match[n]);
}
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23
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Changli Gao
7
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30
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2
100.00%


EXPORT_SYMBOL(xt_unregister_matches);


/*
 * These are weird, but module loading must not be done with mutex
 * held (since they will register), and we have to have a single
 * function to use.
 */

/* Find match, grabs ref.  Returns ERR_PTR() on error. */


struct xt_match *xt_find_match(u8 af, const char *name, u8 revision)
{
	struct xt_match *m;
	int err = -ENOENT;

	mutex_lock(&xt[af].mutex);
	list_for_each_entry(m, &xt[af].match, list) {
		if (strcmp(m->name, name) == 0) {
			if (m->revision == revision) {
				if (try_module_get(m->me)) {
					mutex_unlock(&xt[af].mutex);
					return m;
				}
			} else
				err = -EPROTOTYPE; /* Found something. */
		}
	}
	mutex_unlock(&xt[af].mutex);

	if (af != NFPROTO_UNSPEC)
		/* Try searching again in the family-independent list */
		return xt_find_match(NFPROTO_UNSPEC, name, revision);

	return ERR_PTR(err);
}
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Harald Welte
117
82.98%
1
16.67%
Jan Engelhardt
18
12.77%
2
33.33%
Pablo Neira Ayuso
2
1.42%
1
16.67%
Ingo Molnar
2
1.42%
1
16.67%
Patrick McHardy
2
1.42%
1
16.67%
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141
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6
100.00%


EXPORT_SYMBOL(xt_find_match);


struct xt_match *

xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision)
{
	struct xt_match *match;

	match = xt_find_match(nfproto, name, revision);
	if (IS_ERR(match)) {
		request_module("%st_%s", xt_prefix[nfproto], name);
		match = xt_find_match(nfproto, name, revision);
	}

	return match;
}
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Jan Engelhardt
47
68.12%
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Stephen Hemminger
22
31.88%
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EXPORT_SYMBOL_GPL(xt_request_find_match);

/* Find target, grabs ref.  Returns ERR_PTR() on error. */


struct xt_target *xt_find_target(u8 af, const char *name, u8 revision)
{
	struct xt_target *t;
	int err = -ENOENT;

	mutex_lock(&xt[af].mutex);
	list_for_each_entry(t, &xt[af].target, list) {
		if (strcmp(t->name, name) == 0) {
			if (t->revision == revision) {
				if (try_module_get(t->me)) {
					mutex_unlock(&xt[af].mutex);
					return t;
				}
			} else
				err = -EPROTOTYPE; /* Found something. */
		}
	}
	mutex_unlock(&xt[af].mutex);

	if (af != NFPROTO_UNSPEC)
		/* Try searching again in the family-independent list */
		return xt_find_target(NFPROTO_UNSPEC, name, revision);

	return ERR_PTR(err);
}
Contributors
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Harald Welte
117
82.98%
1
16.67%
Jan Engelhardt
18
12.77%
2
33.33%
Pablo Neira Ayuso
2
1.42%
1
16.67%
Patrick McHardy
2
1.42%
1
16.67%
Ingo Molnar
2
1.42%
1
16.67%
Total
141
100.00%
6
100.00%


EXPORT_SYMBOL(xt_find_target);



struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision)
{
	struct xt_target *target;

	target = xt_find_target(af, name, revision);
	if (IS_ERR(target)) {
		request_module("%st_%s", xt_prefix[af], name);
		target = xt_find_target(af, name, revision);
	}

	return target;
}
Contributors
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Harald Welte
42
60.87%
1
20.00%
Stephen Hemminger
22
31.88%
1
20.00%
Jan Engelhardt
3
4.35%
2
40.00%
Patrick McHardy
2
2.90%
1
20.00%
Total
69
100.00%
5
100.00%


EXPORT_SYMBOL_GPL(xt_request_find_target);




static int xt_obj_to_user(u16 __user *psize, u16 size,
			  void __user *pname, const char *name,
			  u8 __user *prev, u8 rev)
{
	if (put_user(size, psize))
		return -EFAULT;
	if (copy_to_user(pname, name, strlen(name) + 1))
		return -EFAULT;
	if (put_user(rev, prev))
		return -EFAULT;

	return 0;
}

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81
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#define XT_OBJ_TO_USER(U, K, TYPE, C_SIZE)				\
	xt_obj_to_user(&U->u.TYPE##_size, C_SIZE ? : K->u.TYPE##_size,  \
                       U->u.user.name, K->u.kernel.TYPE->name,          \
                       &U->u.user.revision, K->u.kernel.TYPE->revision)



int xt_data_to_user(void __user *dst, const void *src,
		    int usersize, int size)
{
	usersize = usersize ? : size;
	if (copy_to_user(dst, src, usersize))
		return -EFAULT;
	if (usersize != size && clear_user(dst + usersize, size - usersize))
		return -EFAULT;

	return 0;
}
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67
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67
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EXPORT_SYMBOL_GPL(xt_data_to_user);


#define XT_DATA_TO_USER(U, K, TYPE, C_SIZE)				\
	xt_data_to_user(U->data, K->data,                               \
                        K->u.kernel.TYPE->usersize,                     \
                        C_SIZE ? : K->u.kernel.TYPE->TYPE##size)



int xt_match_to_user(const struct xt_entry_match *m,
		     struct xt_entry_match __user *u)
{
	return XT_OBJ_TO_USER(u, m, match, 0) ||
	       XT_DATA_TO_USER(u, m, match, 0);
}
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40
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40
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EXPORT_SYMBOL_GPL(xt_match_to_user);



int xt_target_to_user(const struct xt_entry_target *t,
		      struct xt_entry_target __user *u)
{
	return XT_OBJ_TO_USER(u, t, target, 0) ||
	       XT_DATA_TO_USER(u, t, target, 0);
}
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40
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40
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EXPORT_SYMBOL_GPL(xt_target_to_user);



static int match_revfn(u8 af, const char *name, u8 revision, int *bestp)
{
	const struct xt_match *m;
	int have_rev = 0;

	list_for_each_entry(m, &xt[af].match, list) {
		if (strcmp(m->name, name) == 0) {
			if (m->revision > *bestp)
				*bestp = m->revision;
			if (m->revision == revision)
				have_rev = 1;
		}
	}

	if (af != NFPROTO_UNSPEC && !have_rev)
		return match_revfn(NFPROTO_UNSPEC, name, revision, bestp);

	return have_rev;
}

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Harald Welte
86
78.90%
1
25.00%
Patrick McHardy
21
19.27%
1
25.00%
Jan Engelhardt
2
1.83%
2
50.00%
Total
109
100.00%
4
100.00%



static int target_revfn(u8 af, const char *name, u8 revision, int *bestp)
{
	const struct xt_target *t;
	int have_rev = 0;

	list_for_each_entry(t, &xt[af].target, list) {
		if (strcmp(t->name, name) == 0) {
			if (t->revision > *bestp)
				*bestp = t->revision;
			if (t->revision == revision)
				have_rev = 1;
		}
	}

	if (af != NFPROTO_UNSPEC && !have_rev)
		return target_revfn(NFPROTO_UNSPEC, name, revision, bestp);

	return have_rev;
}

Contributors
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Harald Welte
86
78.90%
1
25.00%
Patrick McHardy
21
19.27%
1
25.00%
Jan Engelhardt
2
1.83%
2
50.00%
Total
109
100.00%
4
100.00%

/* Returns true or false (if no such extension at all) */


int xt_find_revision(u8 af, const char *name, u8 revision, int target,
		     int *err)
{
	int have_rev, best = -1;

	mutex_lock(&xt[af].mutex);
	if (target == 1)
		have_rev = target_revfn(af, name, revision, &best);
	else
		have_rev = match_revfn(af, name, revision, &best);
	mutex_unlock(&xt[af].mutex);

	/* Nothing at all?  Return 0 to try loading module. */
	if (best == -1) {
		*err = -ENOENT;
		return 0;
	}

	*err = best;
	if (!have_rev)
		*err = -EPROTONOSUPPORT;
	return 1;
}
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Harald Welte
123
97.62%
1
25.00%
Ingo Molnar
1
0.79%
1
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Pablo Neira Ayuso
1
0.79%
1
25.00%
Jan Engelhardt
1
0.79%
1
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126
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100.00%


EXPORT_SYMBOL_GPL(xt_find_revision);


static char *

textify_hooks(char *buf, size_t size, unsigned int mask, uint8_t nfproto)
{
	static const char *const inetbr_names[] = {
		"PREROUTING", "INPUT", "FORWARD",
		"OUTPUT", "POSTROUTING", "BROUTING",
        };
	static const char *const arp_names[] = {
		"INPUT", "FORWARD", "OUTPUT",
        };
	const char *const *names;
	unsigned int i, max;
	char *p = buf;
	bool np = false;
	int res;

	names = (nfproto == NFPROTO_ARP) ? arp_names : inetbr_names;
	max   = (nfproto == NFPROTO_ARP) ? ARRAY_SIZE(arp_names) :
	                                   ARRAY_SIZE(inetbr_names);
	*p = '\0';
	for (i = 0; i < max; ++i) {
		if (!(mask & (1 << i)))
			continue;
		res = snprintf(p, size, "%s%s", np ? "/" : "", names[i]);
		if (res > 0) {
			size -= res;
			p += res;
		}
		np = true;
	}

	return buf;
}

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int xt_check_match(struct xt_mtchk_param *par,
		   unsigned int size, u_int8_t proto, bool inv_proto)
{
	int ret;

	if (XT_ALIGN(par->match->matchsize) != size &&
	    par->match->matchsize != -1) {
		/*
                 * ebt_among is exempt from centralized matchsize checking
                 * because it uses a dynamic-size data set.
                 */
		pr_err("%s_tables: %s.%u match: invalid size "
		       "%u (kernel) != (user) %u\n",
		       xt_prefix[par->family], par->match->name,
		       par->match->revision,
		       XT_ALIGN(par->match->matchsize), size);
		return -EINVAL;
	}
	if (par->match->table != NULL &&
	    strcmp(par->match->table, par->table) != 0) {
		pr_err("%s_tables: %s match: only valid in %s table, not %s\n",
		       xt_prefix[par->family], par->match->name,
		       par->match->table, par->table);
		return -EINVAL;
	}
	if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) {
		char used[64], allow[64];

		pr_err("%s_tables: %s match: used from hooks %s, but only "
		       "valid from %s\n",
		       xt_prefix[par->family], par->match->name,
		       textify_hooks(used, sizeof(used), par->hook_mask,
		                     par->family),
		       textify_hooks(allow, sizeof(allow), par->match->hooks,
		                     par->family));
		return -EINVAL;
	}
	if (par->match->proto && (par->match->proto != proto || inv_proto)) {
		pr_err("%s_tables: %s match: only valid for protocol %u\n",
		       xt_prefix[par->family], par->match->name,
		       par->match->proto);
		return -EINVAL;
	}
	if (par->match->checkentry != NULL) {
		ret = par->match->checkentry(par);
		if (ret < 0)
			return ret;
		else if (ret > 0)
			/* Flag up potential errors. */
			return -EIO;
	}
	return 0;
}
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173
50.73%
1
9.09%
Jan Engelhardt
160
46.92%
8
72.73%
Joe Perches
4
1.17%
1
9.09%
Balazs Scheidler
4
1.17%
1
9.09%
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100.00%


EXPORT_SYMBOL_GPL(xt_check_match);

/** xt_check_entry_match - check that matches end before start of target
 *
 * @match: beginning of xt_entry_match
 * @target: beginning of this rules target (alleged end of matches)
 * @alignment: alignment requirement of match structures
 *
 * Validates that all matches add up to the beginning of the target,
 * and that each match covers at least the base structure size.
 *
 * Return: 0 on success, negative errno on failure.
 */


static int xt_check_entry_match(const char *match, const char *target,
				const size_t alignment)
{
	const struct xt_entry_match *pos;
	int length = target - match;

	if (length == 0) /* no matches */
		return 0;

	pos = (struct xt_entry_match *)match;
	do {
		if ((unsigned long)pos % alignment)
			return -EINVAL;

		if (length < (int)sizeof(struct xt_entry_match))
			return -EINVAL;

		if (pos->u.match_size < sizeof(struct xt_entry_match))
			return -EINVAL;

		if (pos->u.match_size > length)
			return -EINVAL;

		length -= pos->u.match_size;
		pos = ((void *)((char *)(pos) + (pos)->u.match_size));
	} while (length > 0);

	return 0;
}

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#ifdef CONFIG_COMPAT


int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta)
{
	struct xt_af *xp = &xt[af];

	if (!xp->compat_tab) {
		if (!xp->number)
			return -EINVAL;
		xp->compat_tab = vmalloc(sizeof(struct compat_delta) * xp->number);
		if (!xp->compat_tab)
			return -ENOMEM;
		xp->cur = 0;
	}

	if (xp->cur >= xp->number)
		return -EINVAL;

	if (xp->cur)
		delta += xp->compat_tab[xp->cur - 1].delta;
	xp->compat_tab[xp->cur].offset = offset;
	xp->compat_tab[xp->cur].delta = delta;
	xp->cur++;
	return 0;
}
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88
59.06%
1
33.33%
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60
40.27%
1
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Jan Engelhardt
1
0.67%
1
33.33%
Total
149
100.00%
3
100.00%


EXPORT_SYMBOL_GPL(xt_compat_add_offset);



void xt_compat_flush_offsets(u_int8_t af)
{
	if (xt[af].compat_tab) {
		vfree(xt[af].compat_tab);
		xt[af].compat_tab = NULL;
		xt[af].number = 0;
		xt[af].cur = 0;
	}
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Patrick McHardy
32
57.14%
1
25.00%
Eric Dumazet
23
41.07%
2
50.00%
Jan Engelhardt
1
1.79%
1
25.00%
Total
56
100.00%
4
100.00%


EXPORT_SYMBOL_GPL(xt_compat_flush_offsets);



int xt_compat_calc_jump(u_int8_t af, unsigned int offset)
{
	struct compat_delta *tmp = xt[af].compat_tab;
	int mid, left = 0, right = xt[af].cur - 1;

	while (left <= right) {
		mid = (left + right) >> 1;
		if (offset > tmp[mid].offset)
			left = mid + 1;
		else if (offset < tmp[mid].offset)
			right = mid - 1;
		else
			return mid ? tmp[mid - 1].delta : 0;
	}
	return left ? tmp[left - 1].delta : 0;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Eric Dumazet
88
70.97%
2
40.00%
Patrick McHardy
33
26.61%
1
20.00%
Florian Westphal
2
1.61%
1
20.00%
Jan Engelhardt
1
0.81%
1
20.00%
Total
124
100.00%
5
100.00%


EXPORT_SYMBOL_GPL(xt_compat_calc_jump);



void xt_compat_init_offsets(u_int8_t af, unsigned int number)
{
	xt[af].number = number;
	xt[af].cur = 0;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Eric Dumazet
30
100.00%
1
100.00%
Total
30
100.00%
1
100.00%


EXPORT_SYMBOL(xt_compat_init_offsets);



int xt_compat_match_offset(const struct xt_match *match)
{
	u_int16_t csize = match->compatsize ? : match->matchsize;
	return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Patrick McHardy
31
86.11%
1
33.33%
Dmitry Mishin
4
11.11%
1
33.33%
Jan Engelhardt
1
2.78%
1
33.33%
Total
36
100.00%
3
100.00%


EXPORT_SYMBOL_GPL(