blob: d7817afc6b9654cd12499135d5e1b9c2617b5440 [file] [log] [blame]
/*
* x_tables core - Backend for {ip,ip6,arp}_tables
*
* Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org>
*
* 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.
*
*/
#include <linux/config.h>
#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/netfilter/x_tables.h>
#include <linux/netfilter_arp.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("[ip,ip6,arp]_tables backend module");
#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
struct xt_af {
struct semaphore mutex;
struct list_head match;
struct list_head target;
struct list_head tables;
};
static struct xt_af *xt;
#ifdef DEBUG_IP_FIREWALL_USER
#define duprintf(format, args...) printk(format , ## args)
#else
#define duprintf(format, args...)
#endif
enum {
TABLE,
TARGET,
MATCH,
};
/* Registration hooks for targets. */
int
xt_register_target(int af, struct xt_target *target)
{
int ret;
ret = down_interruptible(&xt[af].mutex);
if (ret != 0)
return ret;
list_add(&target->list, &xt[af].target);
up(&xt[af].mutex);
return ret;
}
EXPORT_SYMBOL(xt_register_target);
void
xt_unregister_target(int af, struct xt_target *target)
{
down(&xt[af].mutex);
LIST_DELETE(&xt[af].target, target);
up(&xt[af].mutex);
}
EXPORT_SYMBOL(xt_unregister_target);
int
xt_register_match(int af, struct xt_match *match)
{
int ret;
ret = down_interruptible(&xt[af].mutex);
if (ret != 0)
return ret;
list_add(&match->list, &xt[af].match);
up(&xt[af].mutex);
return ret;
}
EXPORT_SYMBOL(xt_register_match);
void
xt_unregister_match(int af, struct xt_match *match)
{
down(&xt[af].mutex);
LIST_DELETE(&xt[af].match, match);
up(&xt[af].mutex);
}
EXPORT_SYMBOL(xt_unregister_match);
/*
* 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(int af, const char *name, u8 revision)
{
struct xt_match *m;
int err = 0;
if (down_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)) {
up(&xt[af].mutex);
return m;
}
} else
err = -EPROTOTYPE; /* Found something. */
}
}
up(&xt[af].mutex);
return ERR_PTR(err);
}
EXPORT_SYMBOL(xt_find_match);
/* Find target, grabs ref. Returns ERR_PTR() on error. */
struct xt_target *xt_find_target(int af, const char *name, u8 revision)
{
struct xt_target *t;
int err = 0;
if (down_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)) {
up(&xt[af].mutex);
return t;
}
} else
err = -EPROTOTYPE; /* Found something. */
}
}
up(&xt[af].mutex);
return ERR_PTR(err);
}
EXPORT_SYMBOL(xt_find_target);
static const char *xt_prefix[NPROTO] = {
[AF_INET] = "ipt_%s",
[AF_INET6] = "ip6t_%s",
[NF_ARP] = "arpt_%s",
};
struct xt_target *xt_request_find_target(int af, const char *name, u8 revision)
{
struct xt_target *target;
target = try_then_request_module(xt_find_target(af, name, revision),
xt_prefix[af], name);
if (IS_ERR(target) || !target)
return NULL;
return target;
}
EXPORT_SYMBOL_GPL(xt_request_find_target);
static int match_revfn(int af, const char *name, u8 revision, int *bestp)
{
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;
}
}
return have_rev;
}
static int target_revfn(int af, const char *name, u8 revision, int *bestp)
{
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;
}
}
return have_rev;
}
/* Returns true or false (if no such extension at all) */
int xt_find_revision(int af, const char *name, u8 revision, int target,
int *err)
{
int have_rev, best = -1;
if (down_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);
up(&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);
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 > num_physpages)
return NULL;
newinfo = kzalloc(sizeof(struct xt_table_info), GFP_KERNEL);
if (!newinfo)
return NULL;
newinfo->size = size;
for_each_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_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(int af, const char *name)
{
struct xt_table *t;
if (down_interruptible(&xt[af].mutex) != 0)
return ERR_PTR(-EINTR);
list_for_each_entry(t, &xt[af].tables, list)
if (strcmp(t->name, name) == 0 && try_module_get(t->me))
return t;
up(&xt[af].mutex);
return NULL;
}
EXPORT_SYMBOL_GPL(xt_find_table_lock);
void xt_table_unlock(struct xt_table *table)
{
up(&xt[table->af].mutex);
}
EXPORT_SYMBOL_GPL(xt_table_unlock);
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 *oldinfo, *private;
/* Do the substitution. */
write_lock_bh(&table->lock);
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);
write_unlock_bh(&table->lock);
*error = -EAGAIN;
return NULL;
}
oldinfo = private;
table->private = newinfo;
newinfo->initial_entries = oldinfo->initial_entries;
write_unlock_bh(&table->lock);
return oldinfo;
}
EXPORT_SYMBOL_GPL(xt_replace_table);
int xt_register_table(struct xt_table *table,
struct xt_table_info *bootstrap,
struct xt_table_info *newinfo)
{
int ret;
struct xt_table_info *private;
ret = down_interruptible(&xt[table->af].mutex);
if (ret != 0)
return ret;
/* Don't autoload: we'd eat our tail... */
if (list_named_find(&xt[table->af].tables, table->name)) {
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;
rwlock_init(&table->lock);
list_prepend(&xt[table->af].tables, table);
ret = 0;
unlock:
up(&xt[table->af].mutex);
return ret;
}
EXPORT_SYMBOL_GPL(xt_register_table);
void *xt_unregister_table(struct xt_table *table)
{
struct xt_table_info *private;
down(&xt[table->af].mutex);
private = table->private;
LIST_DELETE(&xt[table->af].tables, table);
up(&xt[table->af].mutex);
return private;
}
EXPORT_SYMBOL_GPL(xt_unregister_table);
#ifdef CONFIG_PROC_FS
static char *xt_proto_prefix[NPROTO] = {
[AF_INET] = "ip",
[AF_INET6] = "ip6",
[NF_ARP] = "arp",
};
static struct list_head *xt_get_idx(struct list_head *list, struct seq_file *seq, loff_t pos)
{
struct list_head *head = list->next;
if (!head || list_empty(list))
return NULL;
while (pos && (head = head->next)) {
if (head == list)
return NULL;
pos--;
}
return pos ? NULL : head;
}
static struct list_head *type2list(u_int16_t af, u_int16_t type)
{
struct list_head *list;
switch (type) {
case TARGET:
list = &xt[af].target;
break;
case MATCH:
list = &xt[af].match;
break;
case TABLE:
list = &xt[af].tables;
break;
default:
list = NULL;
break;
}
return list;
}
static void *xt_tgt_seq_start(struct seq_file *seq, loff_t *pos)
{
struct proc_dir_entry *pde = (struct proc_dir_entry *) seq->private;
u_int16_t af = (unsigned long)pde->data & 0xffff;
u_int16_t type = (unsigned long)pde->data >> 16;
struct list_head *list;
if (af >= NPROTO)
return NULL;
list = type2list(af, type);
if (!list)
return NULL;
if (down_interruptible(&xt[af].mutex) != 0)
return NULL;
return xt_get_idx(list, seq, *pos);
}
static void *xt_tgt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct proc_dir_entry *pde = seq->private;
u_int16_t af = (unsigned long)pde->data & 0xffff;
u_int16_t type = (unsigned long)pde->data >> 16;
struct list_head *list;
if (af >= NPROTO)
return NULL;
list = type2list(af, type);
if (!list)
return NULL;
(*pos)++;
return xt_get_idx(list, seq, *pos);
}
static void xt_tgt_seq_stop(struct seq_file *seq, void *v)
{
struct proc_dir_entry *pde = seq->private;
u_int16_t af = (unsigned long)pde->data & 0xffff;
up(&xt[af].mutex);
}
static int xt_name_seq_show(struct seq_file *seq, void *v)
{
char *name = (char *)v + sizeof(struct list_head);
if (strlen(name))
return seq_printf(seq, "%s\n", name);
else
return 0;
}
static struct seq_operations xt_tgt_seq_ops = {
.start = xt_tgt_seq_start,
.next = xt_tgt_seq_next,
.stop = xt_tgt_seq_stop,
.show = xt_name_seq_show,
};
static int xt_tgt_open(struct inode *inode, struct file *file)
{
int ret;
ret = seq_open(file, &xt_tgt_seq_ops);
if (!ret) {
struct seq_file *seq = file->private_data;
struct proc_dir_entry *pde = PDE(inode);
seq->private = pde;
}
return ret;
}
static struct file_operations xt_file_ops = {
.owner = THIS_MODULE,
.open = xt_tgt_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#define FORMAT_TABLES "_tables_names"
#define FORMAT_MATCHES "_tables_matches"
#define FORMAT_TARGETS "_tables_targets"
#endif /* CONFIG_PROC_FS */
int xt_proto_init(int af)
{
#ifdef CONFIG_PROC_FS
char buf[XT_FUNCTION_MAXNAMELEN];
struct proc_dir_entry *proc;
#endif
if (af >= NPROTO)
return -EINVAL;
#ifdef CONFIG_PROC_FS
strlcpy(buf, xt_proto_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_TABLES, sizeof(buf));
proc = proc_net_fops_create(buf, 0440, &xt_file_ops);
if (!proc)
goto out;
proc->data = (void *) ((unsigned long) af | (TABLE << 16));
strlcpy(buf, xt_proto_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_MATCHES, sizeof(buf));
proc = proc_net_fops_create(buf, 0440, &xt_file_ops);
if (!proc)
goto out_remove_tables;
proc->data = (void *) ((unsigned long) af | (MATCH << 16));
strlcpy(buf, xt_proto_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_TARGETS, sizeof(buf));
proc = proc_net_fops_create(buf, 0440, &xt_file_ops);
if (!proc)
goto out_remove_matches;
proc->data = (void *) ((unsigned long) af | (TARGET << 16));
#endif
return 0;
#ifdef CONFIG_PROC_FS
out_remove_matches:
strlcpy(buf, xt_proto_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_MATCHES, sizeof(buf));
proc_net_remove(buf);
out_remove_tables:
strlcpy(buf, xt_proto_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_TABLES, sizeof(buf));
proc_net_remove(buf);
out:
return -1;
#endif
}
EXPORT_SYMBOL_GPL(xt_proto_init);
void xt_proto_fini(int af)
{
#ifdef CONFIG_PROC_FS
char buf[XT_FUNCTION_MAXNAMELEN];
strlcpy(buf, xt_proto_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_TABLES, sizeof(buf));
proc_net_remove(buf);
strlcpy(buf, xt_proto_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_TARGETS, sizeof(buf));
proc_net_remove(buf);
strlcpy(buf, xt_proto_prefix[af], sizeof(buf));
strlcat(buf, FORMAT_MATCHES, sizeof(buf));
proc_net_remove(buf);
#endif /*CONFIG_PROC_FS*/
}
EXPORT_SYMBOL_GPL(xt_proto_fini);
static int __init xt_init(void)
{
int i;
xt = kmalloc(sizeof(struct xt_af) * NPROTO, GFP_KERNEL);
if (!xt)
return -ENOMEM;
for (i = 0; i < NPROTO; i++) {
init_MUTEX(&xt[i].mutex);
INIT_LIST_HEAD(&xt[i].target);
INIT_LIST_HEAD(&xt[i].match);
INIT_LIST_HEAD(&xt[i].tables);
}
return 0;
}
static void __exit xt_fini(void)
{
kfree(xt);
}
module_init(xt_init);
module_exit(xt_fini);