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x_tables.c
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/*
* x_tables core - Backend for {ip,ip6,arp}_tables
*
* Copyright (C) 2006-2006 Harald Welte <[email protected]>
*
* Based on existing ip_tables code which is
* Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
* Copyright (C) 2000-2005 Netfilter Core Team <[email protected]>
*
* 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.
*
*/
#include <linux/kernel.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 <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 <[email protected]>");
MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");
#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
struct compat_delta {
struct compat_delta *next;
unsigned int offset;
int delta;
};
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_offsets;
#endif
};
static struct xt_af *xt;
#ifdef DEBUG_IP_FIREWALL_USER
#define duprintf(format, args...) printk(format , ## args)
#else
#define duprintf(format, args...)
#endif
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;
int ret;
ret = mutex_lock_interruptible(&xt[af].mutex);
if (ret != 0)
return ret;
list_add(&target->list, &xt[af].target);
mutex_unlock(&xt[af].mutex);
return ret;
}
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);
}
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;
}
EXPORT_SYMBOL(xt_register_targets);
void
xt_unregister_targets(struct xt_target *target, unsigned int n)
{
unsigned int i;
for (i = 0; i < n; i++)
xt_unregister_target(&target[i]);
}
EXPORT_SYMBOL(xt_unregister_targets);
int
xt_register_match(struct xt_match *match)
{
u_int8_t af = match->family;
int ret;
ret = mutex_lock_interruptible(&xt[af].mutex);
if (ret != 0)
return ret;
list_add(&match->list, &xt[af].match);
mutex_unlock(&xt[af].mutex);
return ret;
}
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);
}
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;
}
EXPORT_SYMBOL(xt_register_matches);
void
xt_unregister_matches(struct xt_match *match, unsigned int n)
{
unsigned int i;
for (i = 0; i < n; i++)
xt_unregister_match(&match[i]);
}
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 try_then_request_module().
*/
/* 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 = 0;
if (mutex_lock_interruptible(&xt[af].mutex) != 0)
return ERR_PTR(-EINTR);
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);
}
EXPORT_SYMBOL(xt_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 = 0;
if (mutex_lock_interruptible(&xt[af].mutex) != 0)
return ERR_PTR(-EINTR);
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);
}
EXPORT_SYMBOL(xt_find_target);
struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision)
{
struct xt_target *target;
target = try_then_request_module(xt_find_target(af, name, revision),
"%st_%s", xt_prefix[af], name);
if (IS_ERR(target) || !target)
return NULL;
return target;
}
EXPORT_SYMBOL_GPL(xt_request_find_target);
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;
}
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;
}
/* 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;
if (mutex_lock_interruptible(&xt[af].mutex) != 0) {
*err = -EINTR;
return 1;
}
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;
}
EXPORT_SYMBOL_GPL(xt_find_revision);
static char *textify_hooks(char *buf, size_t size, unsigned int mask)
{
static const char *const names[] = {
"PREROUTING", "INPUT", "FORWARD",
"OUTPUT", "POSTROUTING", "BROUTING",
};
unsigned int i;
char *p = buf;
bool np = false;
int res;
*p = '\0';
for (i = 0; i < ARRAY_SIZE(names); ++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;
}
int xt_check_match(struct xt_mtchk_param *par,
unsigned int size, u_int8_t proto, bool inv_proto)
{
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),
textify_hooks(allow, sizeof(allow), par->match->hooks));
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 && !par->match->checkentry(par))
return -EINVAL;
return 0;
}
EXPORT_SYMBOL_GPL(xt_check_match);
#ifdef CONFIG_COMPAT
int xt_compat_add_offset(u_int8_t af, unsigned int offset, short delta)
{
struct compat_delta *tmp;
tmp = kmalloc(sizeof(struct compat_delta), GFP_KERNEL);
if (!tmp)
return -ENOMEM;
tmp->offset = offset;
tmp->delta = delta;
if (xt[af].compat_offsets) {
tmp->next = xt[af].compat_offsets->next;
xt[af].compat_offsets->next = tmp;
} else {
xt[af].compat_offsets = tmp;
tmp->next = NULL;
}
return 0;
}
EXPORT_SYMBOL_GPL(xt_compat_add_offset);
void xt_compat_flush_offsets(u_int8_t af)
{
struct compat_delta *tmp, *next;
if (xt[af].compat_offsets) {
for (tmp = xt[af].compat_offsets; tmp; tmp = next) {
next = tmp->next;
kfree(tmp);
}
xt[af].compat_offsets = NULL;
}
}
EXPORT_SYMBOL_GPL(xt_compat_flush_offsets);
int xt_compat_calc_jump(u_int8_t af, unsigned int offset)
{
struct compat_delta *tmp;
int delta;
for (tmp = xt[af].compat_offsets, delta = 0; tmp; tmp = tmp->next)
if (tmp->offset < offset)
delta += tmp->delta;
return delta;
}
EXPORT_SYMBOL_GPL(xt_compat_calc_jump);
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);
}
EXPORT_SYMBOL_GPL(xt_compat_match_offset);
int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
unsigned int *size)
{
const struct xt_match *match = m->u.kernel.match;
struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m;
int pad, off = xt_compat_match_offset(match);
u_int16_t msize = cm->u.user.match_size;
m = *dstptr;
memcpy(m, cm, sizeof(*cm));
if (match->compat_from_user)
match->compat_from_user(m->data, cm->data);
else
memcpy(m->data, cm->data, msize - sizeof(*cm));
pad = XT_ALIGN(match->matchsize) - match->matchsize;
if (pad > 0)
memset(m->data + match->matchsize, 0, pad);
msize += off;
m->u.user.match_size = msize;
*size += off;
*dstptr += msize;
return 0;
}
EXPORT_SYMBOL_GPL(xt_compat_match_from_user);
int xt_compat_match_to_user(const struct xt_entry_match *m,
void __user **dstptr, unsigned int *size)
{
const struct xt_match *match = m->u.kernel.match;
struct compat_xt_entry_match __user *cm = *dstptr;
int off = xt_compat_match_offset(match);
u_int16_t msize = m->u.user.match_size - off;
if (copy_to_user(cm, m, sizeof(*cm)) ||
put_user(msize, &cm->u.user.match_size) ||
copy_to_user(cm->u.user.name, m->u.kernel.match->name,
strlen(m->u.kernel.match->name) + 1))
return -EFAULT;
if (match->compat_to_user) {
if (match->compat_to_user((void __user *)cm->data, m->data))
return -EFAULT;
} else {
if (copy_to_user(cm->data, m->data, msize - sizeof(*cm)))
return -EFAULT;
}
*size -= off;
*dstptr += msize;
return 0;
}
EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
#endif /* CONFIG_COMPAT */
int xt_check_target(struct xt_tgchk_param *par,
unsigned int size, u_int8_t proto, bool inv_proto)
{
if (XT_ALIGN(par->target->targetsize) != size) {
pr_err("%s_tables: %s.%u target: invalid size "
"%u (kernel) != (user) %u\n",
xt_prefix[par->family], par->target->name,
par->target->revision,
XT_ALIGN(par->target->targetsize), size);
return -EINVAL;
}
if (par->target->table != NULL &&
strcmp(par->target->table, par->table) != 0) {
pr_err("%s_tables: %s target: only valid in %s table, not %s\n",
xt_prefix[par->family], par->target->name,
par->target->table, par->table);
return -EINVAL;
}
if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) {
char used[64], allow[64];
pr_err("%s_tables: %s target: used from hooks %s, but only "
"usable from %s\n",
xt_prefix[par->family], par->target->name,
textify_hooks(used, sizeof(used), par->hook_mask),
textify_hooks(allow, sizeof(allow), par->target->hooks));
return -EINVAL;
}
if (par->target->proto && (par->target->proto != proto || inv_proto)) {
pr_err("%s_tables: %s target: only valid for protocol %u\n",
xt_prefix[par->family], par->target->name,
par->target->proto);
return -EINVAL;
}
if (par->target->checkentry != NULL && !par->target->checkentry(par))
return -EINVAL;
return 0;
}
EXPORT_SYMBOL_GPL(xt_check_target);
#ifdef CONFIG_COMPAT
int xt_compat_target_offset(const struct xt_target *target)
{
u_int16_t csize = target->compatsize ? : target->targetsize;
return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize);
}
EXPORT_SYMBOL_GPL(xt_compat_target_offset);
void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
unsigned int *size)
{
const struct xt_target *target = t->u.kernel.target;
struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t;
int pad, off = xt_compat_target_offset(target);
u_int16_t tsize = ct->u.user.target_size;
t = *dstptr;
memcpy(t, ct, sizeof(*ct));
if (target->compat_from_user)
target->compat_from_user(t->data, ct->data);
else
memcpy(t->data, ct->data, tsize - sizeof(*ct));
pad = XT_ALIGN(target->targetsize) - target->targetsize;
if (pad > 0)
memset(t->data + target->targetsize, 0, pad);
tsize += off;
t->u.user.target_size = tsize;
*size += off;
*dstptr += tsize;
}
EXPORT_SYMBOL_GPL(xt_compat_target_from_user);
int xt_compat_target_to_user(const struct xt_entry_target *t,
void __user **dstptr, unsigned int *size)
{
const struct xt_target *target = t->u.kernel.target;
struct compat_xt_entry_target __user *ct = *dstptr;
int off = xt_compat_target_offset(target);
u_int16_t tsize = t->u.user.target_size - off;
if (copy_to_user(ct, t, sizeof(*ct)) ||
put_user(tsize, &ct->u.user.target_size) ||
copy_to_user(ct->u.user.name, t->u.kernel.target->name,
strlen(t->u.kernel.target->name) + 1))
return -EFAULT;
if (target->compat_to_user) {
if (target->compat_to_user((void __user *)ct->data, t->data))
return -EFAULT;
} else {
if (copy_to_user(ct->data, t->data, tsize - sizeof(*ct)))
return -EFAULT;
}
*size -= off;
*dstptr += tsize;
return 0;
}
EXPORT_SYMBOL_GPL(xt_compat_target_to_user);
#endif
struct xt_table_info *xt_alloc_table_info(unsigned int size)
{
struct xt_table_info *newinfo;
int cpu;
/* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages)
return NULL;
newinfo = kzalloc(XT_TABLE_INFO_SZ, GFP_KERNEL);
if (!newinfo)
return NULL;
newinfo->size = size;
for_each_possible_cpu(cpu) {
if (size <= PAGE_SIZE)
newinfo->entries[cpu] = kmalloc_node(size,
GFP_KERNEL,
cpu_to_node(cpu));
else
newinfo->entries[cpu] = vmalloc_node(size,
cpu_to_node(cpu));
if (newinfo->entries[cpu] == NULL) {
xt_free_table_info(newinfo);
return NULL;
}
}
return newinfo;
}
EXPORT_SYMBOL(xt_alloc_table_info);
void xt_free_table_info(struct xt_table_info *info)
{
int cpu;
for_each_possible_cpu(cpu) {
if (info->size <= PAGE_SIZE)
kfree(info->entries[cpu]);
else
vfree(info->entries[cpu]);
}
kfree(info);
}
EXPORT_SYMBOL(xt_free_table_info);
/* Find table by name, grabs mutex & ref. Returns ERR_PTR() on error. */
struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
const char *name)
{
struct xt_table *t;
if (mutex_lock_interruptible(&xt[af].mutex) != 0)
return ERR_PTR(-EINTR);
list_for_each_entry(t, &net->xt.tables[af], list)
if (strcmp(t->name, name) == 0 && try_module_get(t->me))
return t;
mutex_unlock(&xt[af].mutex);
return NULL;
}
EXPORT_SYMBOL_GPL(xt_find_table_lock);
void xt_table_unlock(struct xt_table *table)
{
mutex_unlock(&xt[table->af].mutex);
}
EXPORT_SYMBOL_GPL(xt_table_unlock);
#ifdef CONFIG_COMPAT
void xt_compat_lock(u_int8_t af)
{
mutex_lock(&xt[af].compat_mutex);
}
EXPORT_SYMBOL_GPL(xt_compat_lock);
void xt_compat_unlock(u_int8_t af)
{
mutex_unlock(&xt[af].compat_mutex);
}
EXPORT_SYMBOL_GPL(xt_compat_unlock);
#endif
DEFINE_PER_CPU(struct xt_info_lock, xt_info_locks);
EXPORT_PER_CPU_SYMBOL_GPL(xt_info_locks);
struct xt_table_info *
xt_replace_table(struct xt_table *table,
unsigned int num_counters,
struct xt_table_info *newinfo,
int *error)
{
struct xt_table_info *private;
/* Do the substitution. */
local_bh_disable();
private = table->private;
/* Check inside lock: is the old number correct? */
if (num_counters != private->number) {
duprintf("num_counters != table->private->number (%u/%u)\n",
num_counters, private->number);
local_bh_enable();
*error = -EAGAIN;
return NULL;
}
table->private = newinfo;
newinfo->initial_entries = private->initial_entries;
/*
* Even though table entries have now been swapped, other CPU's
* may still be using the old entries. This is okay, because
* resynchronization happens because of the locking done
* during the get_counters() routine.
*/
local_bh_enable();
return private;
}
EXPORT_SYMBOL_GPL(xt_replace_table);
struct xt_table *xt_register_table(struct net *net,
const struct xt_table *input_table,
struct xt_table_info *bootstrap,
struct xt_table_info *newinfo)
{
int ret;
struct xt_table_info *private;
struct xt_table *t, *table;
/* Don't add one object to multiple lists. */
table = kmemdup(input_table, sizeof(struct xt_table), GFP_KERNEL);
if (!table) {
ret = -ENOMEM;
goto out;
}
ret = mutex_lock_interruptible(&xt[table->af].mutex);
if (ret != 0)
goto out_free;
/* Don't autoload: we'd eat our tail... */
list_for_each_entry(t, &net->xt.tables[table->af], list) {
if (strcmp(t->name, table->name) == 0) {
ret = -EEXIST;
goto unlock;
}
}
/* Simplifies replace_table code. */
table->private = bootstrap;
if (!xt_replace_table(table, 0, newinfo, &ret))
goto unlock;
private = table->private;
duprintf("table->private->number = %u\n", private->number);
/* save number of initial entries */
private->initial_entries = private->number;
list_add(&table->list, &net->xt.tables[table->af]);
mutex_unlock(&xt[table->af].mutex);
return table;
unlock:
mutex_unlock(&xt[table->af].mutex);
out_free:
kfree(table);
out:
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(xt_register_table);
void *xt_unregister_table(struct xt_table *table)
{
struct xt_table_info *private;
mutex_lock(&xt[table->af].mutex);
private = table->private;
list_del(&table->list);
mutex_unlock(&xt[table->af].mutex);
kfree(table);
return private;
}
EXPORT_SYMBOL_GPL(xt_unregister_table);
#ifdef CONFIG_PROC_FS
struct xt_names_priv {
struct seq_net_private p;
u_int8_t af;
};
static void *xt_table_seq_start(struct seq_file *seq, loff_t *pos)
{
struct xt_names_priv *priv = seq->private;
struct net *net = seq_file_net(seq);
u_int8_t af = priv->af;
mutex_lock(&xt[af].mutex);
return seq_list_start(&net->xt.tables[af], *pos);
}
static void *xt_table_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct xt_names_priv *priv = seq->private;
struct net *net = seq_file_net(seq);
u_int8_t af = priv->af;
return seq_list_next(v, &net->xt.tables[af], pos);
}
static void xt_table_seq_stop(struct seq_file *seq, void *v)
{
struct xt_names_priv *priv = seq->private;
u_int8_t af = priv->af;
mutex_unlock(&xt[af].mutex);
}
static int xt_table_seq_show(struct seq_file *seq, void *v)
{
struct xt_table *table = list_entry(v, struct xt_table, list);
if (strlen(table->name))
return seq_printf(seq, "%s\n", table->name);
else
return 0;
}
static const struct seq_operations xt_table_seq_ops = {
.start = xt_table_seq_start,
.next = xt_table_seq_next,
.stop = xt_table_seq_stop,
.show = xt_table_seq_show,
};
static int xt_table_open(struct inode *inode, struct file *file)
{
int ret;
struct xt_names_priv *priv;
ret = seq_open_net(inode, file, &xt_table_seq_ops,
sizeof(struct xt_names_priv));
if (!ret) {
priv = ((struct seq_file *)file->private_data)->private;
priv->af = (unsigned long)PDE(inode)->data;
}
return ret;
}
static const struct file_operations xt_table_ops = {
.owner = THIS_MODULE,
.open = xt_table_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_net,
};
/*
* Traverse state for ip{,6}_{tables,matches} for helping crossing
* the multi-AF mutexes.
*/
struct nf_mttg_trav {
struct list_head *head, *curr;
uint8_t class, nfproto;
};
enum {
MTTG_TRAV_INIT,
MTTG_TRAV_NFP_UNSPEC,
MTTG_TRAV_NFP_SPEC,
MTTG_TRAV_DONE,
};
static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos,
bool is_target)
{
static const uint8_t next_class[] = {
[MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC,
[MTTG_TRAV_NFP_SPEC] = MTTG_TRAV_DONE,
};
struct nf_mttg_trav *trav = seq->private;
switch (trav->class) {
case MTTG_TRAV_INIT:
trav->class = MTTG_TRAV_NFP_UNSPEC;
mutex_lock(&xt[NFPROTO_UNSPEC].mutex);
trav->head = trav->curr = is_target ?
&xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match;
break;
case MTTG_TRAV_NFP_UNSPEC:
trav->curr = trav->curr->next;
if (trav->curr != trav->head)
break;
mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
mutex_lock(&xt[trav->nfproto].mutex);
trav->head = trav->curr = is_target ?
&xt[trav->nfproto].target : &xt[trav->nfproto].match;
trav->class = next_class[trav->class];
break;
case MTTG_TRAV_NFP_SPEC:
trav->curr = trav->curr->next;
if (trav->curr != trav->head)
break;
/* fallthru, _stop will unlock */
default:
return NULL;
}
if (ppos != NULL)
++*ppos;
return trav;
}
static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos,
bool is_target)
{
struct nf_mttg_trav *trav = seq->private;
unsigned int j;
trav->class = MTTG_TRAV_INIT;
for (j = 0; j < *pos; ++j)
if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL)
return NULL;
return trav;
}
static void xt_mttg_seq_stop(struct seq_file *seq, void *v)
{
struct nf_mttg_trav *trav = seq->private;
switch (trav->class) {
case MTTG_TRAV_NFP_UNSPEC:
mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
break;
case MTTG_TRAV_NFP_SPEC:
mutex_unlock(&xt[trav->nfproto].mutex);
break;
}
}
static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos)
{
return xt_mttg_seq_start(seq, pos, false);
}
static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
{
return xt_mttg_seq_next(seq, v, ppos, false);
}
static int xt_match_seq_show(struct seq_file *seq, void *v)
{
const struct nf_mttg_trav *trav = seq->private;
const struct xt_match *match;
switch (trav->class) {
case MTTG_TRAV_NFP_UNSPEC:
case MTTG_TRAV_NFP_SPEC:
if (trav->curr == trav->head)
return 0;
match = list_entry(trav->curr, struct xt_match, list);
return (*match->name == '\0') ? 0 :
seq_printf(seq, "%s\n", match->name);
}
return 0;
}
static const struct seq_operations xt_match_seq_ops = {
.start = xt_match_seq_start,
.next = xt_match_seq_next,
.stop = xt_mttg_seq_stop,
.show = xt_match_seq_show,
};