625 lines
13 KiB
C
625 lines
13 KiB
C
/*
|
|
* 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);
|
|
|