blob: 622d7c671cb78533082f9bf0b655a3bbffcd2f92 [file] [log] [blame]
/* Connection state tracking for netfilter. This is separated from,
but required by, the NAT layer; it can also be used by an iptables
extension. */
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.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/types.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/vmalloc.h>
#include <linux/stddef.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <linux/err.h>
#include <linux/percpu.h>
#include <linux/moduleparam.h>
#include <linux/notifier.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/socket.h>
#include <linux/mm.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_extend.h>
#include <net/netfilter/nf_conntrack_acct.h>
#include <net/netfilter/nf_nat.h>
#define NF_CONNTRACK_VERSION "0.5.0"
unsigned int
(*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
enum nf_nat_manip_type manip,
struct nlattr *attr) __read_mostly;
EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
DEFINE_SPINLOCK(nf_conntrack_lock);
EXPORT_SYMBOL_GPL(nf_conntrack_lock);
unsigned int nf_conntrack_htable_size __read_mostly;
EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
int nf_conntrack_max __read_mostly;
EXPORT_SYMBOL_GPL(nf_conntrack_max);
struct nf_conn nf_conntrack_untracked __read_mostly;
EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
static struct kmem_cache *nf_conntrack_cachep __read_mostly;
static int nf_conntrack_hash_rnd_initted;
static unsigned int nf_conntrack_hash_rnd;
static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
unsigned int size, unsigned int rnd)
{
unsigned int n;
u_int32_t h;
/* The direction must be ignored, so we hash everything up to the
* destination ports (which is a multiple of 4) and treat the last
* three bytes manually.
*/
n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
h = jhash2((u32 *)tuple, n,
rnd ^ (((__force __u16)tuple->dst.u.all << 16) |
tuple->dst.protonum));
return ((u64)h * size) >> 32;
}
static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
{
return __hash_conntrack(tuple, nf_conntrack_htable_size,
nf_conntrack_hash_rnd);
}
bool
nf_ct_get_tuple(const struct sk_buff *skb,
unsigned int nhoff,
unsigned int dataoff,
u_int16_t l3num,
u_int8_t protonum,
struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_l3proto *l3proto,
const struct nf_conntrack_l4proto *l4proto)
{
memset(tuple, 0, sizeof(*tuple));
tuple->src.l3num = l3num;
if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
return false;
tuple->dst.protonum = protonum;
tuple->dst.dir = IP_CT_DIR_ORIGINAL;
return l4proto->pkt_to_tuple(skb, dataoff, tuple);
}
EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
u_int16_t l3num, struct nf_conntrack_tuple *tuple)
{
struct nf_conntrack_l3proto *l3proto;
struct nf_conntrack_l4proto *l4proto;
unsigned int protoff;
u_int8_t protonum;
int ret;
rcu_read_lock();
l3proto = __nf_ct_l3proto_find(l3num);
ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
if (ret != NF_ACCEPT) {
rcu_read_unlock();
return false;
}
l4proto = __nf_ct_l4proto_find(l3num, protonum);
ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
l3proto, l4proto);
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
bool
nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
const struct nf_conntrack_tuple *orig,
const struct nf_conntrack_l3proto *l3proto,
const struct nf_conntrack_l4proto *l4proto)
{
memset(inverse, 0, sizeof(*inverse));
inverse->src.l3num = orig->src.l3num;
if (l3proto->invert_tuple(inverse, orig) == 0)
return false;
inverse->dst.dir = !orig->dst.dir;
inverse->dst.protonum = orig->dst.protonum;
return l4proto->invert_tuple(inverse, orig);
}
EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
static void
clean_from_lists(struct nf_conn *ct)
{
pr_debug("clean_from_lists(%p)\n", ct);
hlist_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
hlist_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode);
/* Destroy all pending expectations */
nf_ct_remove_expectations(ct);
}
static void
destroy_conntrack(struct nf_conntrack *nfct)
{
struct nf_conn *ct = (struct nf_conn *)nfct;
struct net *net = nf_ct_net(ct);
struct nf_conntrack_l4proto *l4proto;
pr_debug("destroy_conntrack(%p)\n", ct);
NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
NF_CT_ASSERT(!timer_pending(&ct->timeout));
nf_conntrack_event(IPCT_DESTROY, ct);
set_bit(IPS_DYING_BIT, &ct->status);
/* To make sure we don't get any weird locking issues here:
* destroy_conntrack() MUST NOT be called with a write lock
* to nf_conntrack_lock!!! -HW */
rcu_read_lock();
l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
if (l4proto && l4proto->destroy)
l4proto->destroy(ct);
rcu_read_unlock();
spin_lock_bh(&nf_conntrack_lock);
/* Expectations will have been removed in clean_from_lists,
* except TFTP can create an expectation on the first packet,
* before connection is in the list, so we need to clean here,
* too. */
nf_ct_remove_expectations(ct);
/* We overload first tuple to link into unconfirmed list. */
if (!nf_ct_is_confirmed(ct)) {
BUG_ON(hlist_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode));
hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
}
NF_CT_STAT_INC(net, delete);
spin_unlock_bh(&nf_conntrack_lock);
if (ct->master)
nf_ct_put(ct->master);
pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
nf_conntrack_free(ct);
}
static void death_by_timeout(unsigned long ul_conntrack)
{
struct nf_conn *ct = (void *)ul_conntrack;
struct net *net = nf_ct_net(ct);
struct nf_conn_help *help = nfct_help(ct);
struct nf_conntrack_helper *helper;
if (help) {
rcu_read_lock();
helper = rcu_dereference(help->helper);
if (helper && helper->destroy)
helper->destroy(ct);
rcu_read_unlock();
}
spin_lock_bh(&nf_conntrack_lock);
/* Inside lock so preempt is disabled on module removal path.
* Otherwise we can get spurious warnings. */
NF_CT_STAT_INC(net, delete_list);
clean_from_lists(ct);
spin_unlock_bh(&nf_conntrack_lock);
nf_ct_put(ct);
}
struct nf_conntrack_tuple_hash *
__nf_conntrack_find(struct net *net, const struct nf_conntrack_tuple *tuple)
{
struct nf_conntrack_tuple_hash *h;
struct hlist_node *n;
unsigned int hash = hash_conntrack(tuple);
/* Disable BHs the entire time since we normally need to disable them
* at least once for the stats anyway.
*/
local_bh_disable();
hlist_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnode) {
if (nf_ct_tuple_equal(tuple, &h->tuple)) {
NF_CT_STAT_INC(net, found);
local_bh_enable();
return h;
}
NF_CT_STAT_INC(net, searched);
}
local_bh_enable();
return NULL;
}
EXPORT_SYMBOL_GPL(__nf_conntrack_find);
/* Find a connection corresponding to a tuple. */
struct nf_conntrack_tuple_hash *
nf_conntrack_find_get(struct net *net, const struct nf_conntrack_tuple *tuple)
{
struct nf_conntrack_tuple_hash *h;
struct nf_conn *ct;
rcu_read_lock();
h = __nf_conntrack_find(net, tuple);
if (h) {
ct = nf_ct_tuplehash_to_ctrack(h);
if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
h = NULL;
}
rcu_read_unlock();
return h;
}
EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
static void __nf_conntrack_hash_insert(struct nf_conn *ct,
unsigned int hash,
unsigned int repl_hash)
{
struct net *net = nf_ct_net(ct);
hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
&net->ct.hash[hash]);
hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode,
&net->ct.hash[repl_hash]);
}
void nf_conntrack_hash_insert(struct nf_conn *ct)
{
unsigned int hash, repl_hash;
hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
spin_lock_bh(&nf_conntrack_lock);
__nf_conntrack_hash_insert(ct, hash, repl_hash);
spin_unlock_bh(&nf_conntrack_lock);
}
EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
/* Confirm a connection given skb; places it in hash table */
int
__nf_conntrack_confirm(struct sk_buff *skb)
{
unsigned int hash, repl_hash;
struct nf_conntrack_tuple_hash *h;
struct nf_conn *ct;
struct nf_conn_help *help;
struct hlist_node *n;
enum ip_conntrack_info ctinfo;
struct net *net;
ct = nf_ct_get(skb, &ctinfo);
net = nf_ct_net(ct);
/* ipt_REJECT uses nf_conntrack_attach to attach related
ICMP/TCP RST packets in other direction. Actual packet
which created connection will be IP_CT_NEW or for an
expected connection, IP_CT_RELATED. */
if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
return NF_ACCEPT;
hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
/* We're not in hash table, and we refuse to set up related
connections for unconfirmed conns. But packet copies and
REJECT will give spurious warnings here. */
/* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
/* No external references means noone else could have
confirmed us. */
NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
pr_debug("Confirming conntrack %p\n", ct);
spin_lock_bh(&nf_conntrack_lock);
/* See if there's one in the list already, including reverse:
NAT could have grabbed it without realizing, since we're
not in the hash. If there is, we lost race. */
hlist_for_each_entry(h, n, &net->ct.hash[hash], hnode)
if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
&h->tuple))
goto out;
hlist_for_each_entry(h, n, &net->ct.hash[repl_hash], hnode)
if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
&h->tuple))
goto out;
/* Remove from unconfirmed list */
hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
__nf_conntrack_hash_insert(ct, hash, repl_hash);
/* Timer relative to confirmation time, not original
setting time, otherwise we'd get timer wrap in
weird delay cases. */
ct->timeout.expires += jiffies;
add_timer(&ct->timeout);
atomic_inc(&ct->ct_general.use);
set_bit(IPS_CONFIRMED_BIT, &ct->status);
NF_CT_STAT_INC(net, insert);
spin_unlock_bh(&nf_conntrack_lock);
help = nfct_help(ct);
if (help && help->helper)
nf_conntrack_event_cache(IPCT_HELPER, ct);
#ifdef CONFIG_NF_NAT_NEEDED
if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
nf_conntrack_event_cache(IPCT_NATINFO, ct);
#endif
nf_conntrack_event_cache(master_ct(ct) ?
IPCT_RELATED : IPCT_NEW, ct);
return NF_ACCEPT;
out:
NF_CT_STAT_INC(net, insert_failed);
spin_unlock_bh(&nf_conntrack_lock);
return NF_DROP;
}
EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
/* Returns true if a connection correspondings to the tuple (required
for NAT). */
int
nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
const struct nf_conn *ignored_conntrack)
{
struct net *net = nf_ct_net(ignored_conntrack);
struct nf_conntrack_tuple_hash *h;
struct hlist_node *n;
unsigned int hash = hash_conntrack(tuple);
/* Disable BHs the entire time since we need to disable them at
* least once for the stats anyway.
*/
rcu_read_lock_bh();
hlist_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnode) {
if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
nf_ct_tuple_equal(tuple, &h->tuple)) {
NF_CT_STAT_INC(net, found);
rcu_read_unlock_bh();
return 1;
}
NF_CT_STAT_INC(net, searched);
}
rcu_read_unlock_bh();
return 0;
}
EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
#define NF_CT_EVICTION_RANGE 8
/* There's a small race here where we may free a just-assured
connection. Too bad: we're in trouble anyway. */
static noinline int early_drop(struct net *net, unsigned int hash)
{
/* Use oldest entry, which is roughly LRU */
struct nf_conntrack_tuple_hash *h;
struct nf_conn *ct = NULL, *tmp;
struct hlist_node *n;
unsigned int i, cnt = 0;
int dropped = 0;
rcu_read_lock();
for (i = 0; i < nf_conntrack_htable_size; i++) {
hlist_for_each_entry_rcu(h, n, &net->ct.hash[hash],
hnode) {
tmp = nf_ct_tuplehash_to_ctrack(h);
if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
ct = tmp;
cnt++;
}
if (ct && unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
ct = NULL;
if (ct || cnt >= NF_CT_EVICTION_RANGE)
break;
hash = (hash + 1) % nf_conntrack_htable_size;
}
rcu_read_unlock();
if (!ct)
return dropped;
if (del_timer(&ct->timeout)) {
death_by_timeout((unsigned long)ct);
dropped = 1;
NF_CT_STAT_INC_ATOMIC(net, early_drop);
}
nf_ct_put(ct);
return dropped;
}
struct nf_conn *nf_conntrack_alloc(struct net *net,
const struct nf_conntrack_tuple *orig,
const struct nf_conntrack_tuple *repl,
gfp_t gfp)
{
struct nf_conn *ct = NULL;
if (unlikely(!nf_conntrack_hash_rnd_initted)) {
get_random_bytes(&nf_conntrack_hash_rnd, 4);
nf_conntrack_hash_rnd_initted = 1;
}
/* We don't want any race condition at early drop stage */
atomic_inc(&net->ct.count);
if (nf_conntrack_max &&
unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
unsigned int hash = hash_conntrack(orig);
if (!early_drop(net, hash)) {
atomic_dec(&net->ct.count);
if (net_ratelimit())
printk(KERN_WARNING
"nf_conntrack: table full, dropping"
" packet.\n");
return ERR_PTR(-ENOMEM);
}
}
ct = kmem_cache_zalloc(nf_conntrack_cachep, gfp);
if (ct == NULL) {
pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
atomic_dec(&net->ct.count);
return ERR_PTR(-ENOMEM);
}
atomic_set(&ct->ct_general.use, 1);
ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
/* Don't set timer yet: wait for confirmation */
setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
#ifdef CONFIG_NET_NS
ct->ct_net = net;
#endif
INIT_RCU_HEAD(&ct->rcu);
return ct;
}
EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
static void nf_conntrack_free_rcu(struct rcu_head *head)
{
struct nf_conn *ct = container_of(head, struct nf_conn, rcu);
struct net *net = nf_ct_net(ct);
nf_ct_ext_free(ct);
kmem_cache_free(nf_conntrack_cachep, ct);
atomic_dec(&net->ct.count);
}
void nf_conntrack_free(struct nf_conn *ct)
{
nf_ct_ext_destroy(ct);
call_rcu(&ct->rcu, nf_conntrack_free_rcu);
}
EXPORT_SYMBOL_GPL(nf_conntrack_free);
/* Allocate a new conntrack: we return -ENOMEM if classification
failed due to stress. Otherwise it really is unclassifiable. */
static struct nf_conntrack_tuple_hash *
init_conntrack(struct net *net,
const struct nf_conntrack_tuple *tuple,
struct nf_conntrack_l3proto *l3proto,
struct nf_conntrack_l4proto *l4proto,
struct sk_buff *skb,
unsigned int dataoff)
{
struct nf_conn *ct;
struct nf_conn_help *help;
struct nf_conntrack_tuple repl_tuple;
struct nf_conntrack_expect *exp;
if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
pr_debug("Can't invert tuple.\n");
return NULL;
}
ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC);
if (ct == NULL || IS_ERR(ct)) {
pr_debug("Can't allocate conntrack.\n");
return (struct nf_conntrack_tuple_hash *)ct;
}
if (!l4proto->new(ct, skb, dataoff)) {
nf_conntrack_free(ct);
pr_debug("init conntrack: can't track with proto module\n");
return NULL;
}
nf_ct_acct_ext_add(ct, GFP_ATOMIC);
spin_lock_bh(&nf_conntrack_lock);
exp = nf_ct_find_expectation(net, tuple);
if (exp) {
pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
ct, exp);
/* Welcome, Mr. Bond. We've been expecting you... */
__set_bit(IPS_EXPECTED_BIT, &ct->status);
ct->master = exp->master;
if (exp->helper) {
help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
if (help)
rcu_assign_pointer(help->helper, exp->helper);
}
#ifdef CONFIG_NF_CONNTRACK_MARK
ct->mark = exp->master->mark;
#endif
#ifdef CONFIG_NF_CONNTRACK_SECMARK
ct->secmark = exp->master->secmark;
#endif
nf_conntrack_get(&ct->master->ct_general);
NF_CT_STAT_INC(net, expect_new);
} else {
struct nf_conntrack_helper *helper;
helper = __nf_ct_helper_find(&repl_tuple);
if (helper) {
help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
if (help)
rcu_assign_pointer(help->helper, helper);
}
NF_CT_STAT_INC(net, new);
}
/* Overload tuple linked list to put us in unconfirmed list. */
hlist_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
&net->ct.unconfirmed);
spin_unlock_bh(&nf_conntrack_lock);
if (exp) {
if (exp->expectfn)
exp->expectfn(ct, exp);
nf_ct_expect_put(exp);
}
return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
}
/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
static inline struct nf_conn *
resolve_normal_ct(struct net *net,
struct sk_buff *skb,
unsigned int dataoff,
u_int16_t l3num,
u_int8_t protonum,
struct nf_conntrack_l3proto *l3proto,
struct nf_conntrack_l4proto *l4proto,
int *set_reply,
enum ip_conntrack_info *ctinfo)
{
struct nf_conntrack_tuple tuple;
struct nf_conntrack_tuple_hash *h;
struct nf_conn *ct;
if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
dataoff, l3num, protonum, &tuple, l3proto,
l4proto)) {
pr_debug("resolve_normal_ct: Can't get tuple\n");
return NULL;
}
/* look for tuple match */
h = nf_conntrack_find_get(net, &tuple);
if (!h) {
h = init_conntrack(net, &tuple, l3proto, l4proto, skb, dataoff);
if (!h)
return NULL;
if (IS_ERR(h))
return (void *)h;
}
ct = nf_ct_tuplehash_to_ctrack(h);
/* It exists; we have (non-exclusive) reference. */
if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
*ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
/* Please set reply bit if this packet OK */
*set_reply = 1;
} else {
/* Once we've had two way comms, always ESTABLISHED. */
if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
*ctinfo = IP_CT_ESTABLISHED;
} else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
pr_debug("nf_conntrack_in: related packet for %p\n",
ct);
*ctinfo = IP_CT_RELATED;
} else {
pr_debug("nf_conntrack_in: new packet for %p\n", ct);
*ctinfo = IP_CT_NEW;
}
*set_reply = 0;
}
skb->nfct = &ct->ct_general;
skb->nfctinfo = *ctinfo;
return ct;
}
unsigned int
nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
struct sk_buff *skb)
{
struct nf_conn *ct;
enum ip_conntrack_info ctinfo;
struct nf_conntrack_l3proto *l3proto;
struct nf_conntrack_l4proto *l4proto;
unsigned int dataoff;
u_int8_t protonum;
int set_reply = 0;
int ret;
/* Previously seen (loopback or untracked)? Ignore. */
if (skb->nfct) {
NF_CT_STAT_INC_ATOMIC(net, ignore);
return NF_ACCEPT;
}
/* rcu_read_lock()ed by nf_hook_slow */
l3proto = __nf_ct_l3proto_find(pf);
ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
&dataoff, &protonum);
if (ret <= 0) {
pr_debug("not prepared to track yet or error occured\n");
NF_CT_STAT_INC_ATOMIC(net, error);
NF_CT_STAT_INC_ATOMIC(net, invalid);
return -ret;
}
l4proto = __nf_ct_l4proto_find(pf, protonum);
/* It may be an special packet, error, unclean...
* inverse of the return code tells to the netfilter
* core what to do with the packet. */
if (l4proto->error != NULL) {
ret = l4proto->error(net, skb, dataoff, &ctinfo, pf, hooknum);
if (ret <= 0) {
NF_CT_STAT_INC_ATOMIC(net, error);
NF_CT_STAT_INC_ATOMIC(net, invalid);
return -ret;
}
}
ct = resolve_normal_ct(net, skb, dataoff, pf, protonum,
l3proto, l4proto, &set_reply, &ctinfo);
if (!ct) {
/* Not valid part of a connection */
NF_CT_STAT_INC_ATOMIC(net, invalid);
return NF_ACCEPT;
}
if (IS_ERR(ct)) {
/* Too stressed to deal. */
NF_CT_STAT_INC_ATOMIC(net, drop);
return NF_DROP;
}
NF_CT_ASSERT(skb->nfct);
ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
if (ret < 0) {
/* Invalid: inverse of the return code tells
* the netfilter core what to do */
pr_debug("nf_conntrack_in: Can't track with proto module\n");
nf_conntrack_put(skb->nfct);
skb->nfct = NULL;
NF_CT_STAT_INC_ATOMIC(net, invalid);
return -ret;
}
if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
nf_conntrack_event_cache(IPCT_STATUS, ct);
return ret;
}
EXPORT_SYMBOL_GPL(nf_conntrack_in);
bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
const struct nf_conntrack_tuple *orig)
{
bool ret;
rcu_read_lock();
ret = nf_ct_invert_tuple(inverse, orig,
__nf_ct_l3proto_find(orig->src.l3num),
__nf_ct_l4proto_find(orig->src.l3num,
orig->dst.protonum));
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
/* Alter reply tuple (maybe alter helper). This is for NAT, and is
implicitly racy: see __nf_conntrack_confirm */
void nf_conntrack_alter_reply(struct nf_conn *ct,
const struct nf_conntrack_tuple *newreply)
{
struct nf_conn_help *help = nfct_help(ct);
struct nf_conntrack_helper *helper;
/* Should be unconfirmed, so not in hash table yet */
NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
pr_debug("Altering reply tuple of %p to ", ct);
nf_ct_dump_tuple(newreply);
ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
if (ct->master || (help && !hlist_empty(&help->expectations)))
return;
rcu_read_lock();
helper = __nf_ct_helper_find(newreply);
if (helper == NULL) {
if (help)
rcu_assign_pointer(help->helper, NULL);
goto out;
}
if (help == NULL) {
help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
if (help == NULL)
goto out;
} else {
memset(&help->help, 0, sizeof(help->help));
}
rcu_assign_pointer(help->helper, helper);
out:
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
/* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
void __nf_ct_refresh_acct(struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
const struct sk_buff *skb,
unsigned long extra_jiffies,
int do_acct)
{
int event = 0;
NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
NF_CT_ASSERT(skb);
spin_lock_bh(&nf_conntrack_lock);
/* Only update if this is not a fixed timeout */
if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
goto acct;
/* If not in hash table, timer will not be active yet */
if (!nf_ct_is_confirmed(ct)) {
ct->timeout.expires = extra_jiffies;
event = IPCT_REFRESH;
} else {
unsigned long newtime = jiffies + extra_jiffies;
/* Only update the timeout if the new timeout is at least
HZ jiffies from the old timeout. Need del_timer for race
avoidance (may already be dying). */
if (newtime - ct->timeout.expires >= HZ
&& del_timer(&ct->timeout)) {
ct->timeout.expires = newtime;
add_timer(&ct->timeout);
event = IPCT_REFRESH;
}
}
acct:
if (do_acct) {
struct nf_conn_counter *acct;
acct = nf_conn_acct_find(ct);
if (acct) {
acct[CTINFO2DIR(ctinfo)].packets++;
acct[CTINFO2DIR(ctinfo)].bytes +=
skb->len - skb_network_offset(skb);
}
}
spin_unlock_bh(&nf_conntrack_lock);
/* must be unlocked when calling event cache */
if (event)
nf_conntrack_event_cache(event, ct);
}
EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
bool __nf_ct_kill_acct(struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
const struct sk_buff *skb,
int do_acct)
{
if (do_acct) {
struct nf_conn_counter *acct;
spin_lock_bh(&nf_conntrack_lock);
acct = nf_conn_acct_find(ct);
if (acct) {
acct[CTINFO2DIR(ctinfo)].packets++;
acct[CTINFO2DIR(ctinfo)].bytes +=
skb->len - skb_network_offset(skb);
}
spin_unlock_bh(&nf_conntrack_lock);
}
if (del_timer(&ct->timeout)) {
ct->timeout.function((unsigned long)ct);
return true;
}
return false;
}
EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
#include <linux/mutex.h>
/* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
* in ip_conntrack_core, since we don't want the protocols to autoload
* or depend on ctnetlink */
int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
const struct nf_conntrack_tuple *tuple)
{
NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
return 0;
nla_put_failure:
return -1;
}
EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
[CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
[CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
};
EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
struct nf_conntrack_tuple *t)
{
if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
return -EINVAL;
t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
return 0;
}
EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
#endif
/* Used by ipt_REJECT and ip6t_REJECT. */
static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
{
struct nf_conn *ct;
enum ip_conntrack_info ctinfo;
/* This ICMP is in reverse direction to the packet which caused it */
ct = nf_ct_get(skb, &ctinfo);
if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
else
ctinfo = IP_CT_RELATED;
/* Attach to new skbuff, and increment count */
nskb->nfct = &ct->ct_general;
nskb->nfctinfo = ctinfo;
nf_conntrack_get(nskb->nfct);
}
/* Bring out ya dead! */
static struct nf_conn *
get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
void *data, unsigned int *bucket)
{
struct nf_conntrack_tuple_hash *h;
struct nf_conn *ct;
struct hlist_node *n;
spin_lock_bh(&nf_conntrack_lock);
for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
hlist_for_each_entry(h, n, &net->ct.hash[*bucket], hnode) {
ct = nf_ct_tuplehash_to_ctrack(h);
if (iter(ct, data))
goto found;
}
}
hlist_for_each_entry(h, n, &net->ct.unconfirmed, hnode) {
ct = nf_ct_tuplehash_to_ctrack(h);
if (iter(ct, data))
set_bit(IPS_DYING_BIT, &ct->status);
}
spin_unlock_bh(&nf_conntrack_lock);
return NULL;
found:
atomic_inc(&ct->ct_general.use);
spin_unlock_bh(&nf_conntrack_lock);
return ct;
}
void nf_ct_iterate_cleanup(struct net *net,
int (*iter)(struct nf_conn *i, void *data),
void *data)
{
struct nf_conn *ct;
unsigned int bucket = 0;
while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
/* Time to push up daises... */
if (del_timer(&ct->timeout))
death_by_timeout((unsigned long)ct);
/* ... else the timer will get him soon. */
nf_ct_put(ct);
}
}
EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
static int kill_all(struct nf_conn *i, void *data)
{
return 1;
}
void nf_ct_free_hashtable(struct hlist_head *hash, int vmalloced, unsigned int size)
{
if (vmalloced)
vfree(hash);
else
free_pages((unsigned long)hash,
get_order(sizeof(struct hlist_head) * size));
}
EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
void nf_conntrack_flush(struct net *net)
{
nf_ct_iterate_cleanup(net, kill_all, NULL);
}
EXPORT_SYMBOL_GPL(nf_conntrack_flush);
static void nf_conntrack_cleanup_init_net(void)
{
nf_conntrack_helper_fini();
nf_conntrack_proto_fini();
kmem_cache_destroy(nf_conntrack_cachep);
}
static void nf_conntrack_cleanup_net(struct net *net)
{
nf_ct_event_cache_flush(net);
nf_conntrack_ecache_fini(net);
i_see_dead_people:
nf_conntrack_flush(net);
if (atomic_read(&net->ct.count) != 0) {
schedule();
goto i_see_dead_people;
}
/* wait until all references to nf_conntrack_untracked are dropped */
while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
schedule();
nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
nf_conntrack_htable_size);
nf_conntrack_acct_fini(net);
nf_conntrack_expect_fini(net);
free_percpu(net->ct.stat);
}
/* Mishearing the voices in his head, our hero wonders how he's
supposed to kill the mall. */
void nf_conntrack_cleanup(struct net *net)
{
if (net_eq(net, &init_net))
rcu_assign_pointer(ip_ct_attach, NULL);
/* This makes sure all current packets have passed through
netfilter framework. Roll on, two-stage module
delete... */
synchronize_net();
nf_conntrack_cleanup_net(net);
if (net_eq(net, &init_net)) {
rcu_assign_pointer(nf_ct_destroy, NULL);
nf_conntrack_cleanup_init_net();
}
}
struct hlist_head *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced)
{
struct hlist_head *hash;
unsigned int size, i;
*vmalloced = 0;
size = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_head));
hash = (void*)__get_free_pages(GFP_KERNEL|__GFP_NOWARN,
get_order(sizeof(struct hlist_head)
* size));
if (!hash) {
*vmalloced = 1;
printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
hash = vmalloc(sizeof(struct hlist_head) * size);
}
if (hash)
for (i = 0; i < size; i++)
INIT_HLIST_HEAD(&hash[i]);
return hash;
}
EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
{
int i, bucket, vmalloced, old_vmalloced;
unsigned int hashsize, old_size;
int rnd;
struct hlist_head *hash, *old_hash;
struct nf_conntrack_tuple_hash *h;
/* On boot, we can set this without any fancy locking. */
if (!nf_conntrack_htable_size)
return param_set_uint(val, kp);
hashsize = simple_strtoul(val, NULL, 0);
if (!hashsize)
return -EINVAL;
hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced);
if (!hash)
return -ENOMEM;
/* We have to rehahs for the new table anyway, so we also can
* use a newrandom seed */
get_random_bytes(&rnd, 4);
/* Lookups in the old hash might happen in parallel, which means we
* might get false negatives during connection lookup. New connections
* created because of a false negative won't make it into the hash
* though since that required taking the lock.
*/
spin_lock_bh(&nf_conntrack_lock);
for (i = 0; i < nf_conntrack_htable_size; i++) {
while (!hlist_empty(&init_net.ct.hash[i])) {
h = hlist_entry(init_net.ct.hash[i].first,
struct nf_conntrack_tuple_hash, hnode);
hlist_del_rcu(&h->hnode);
bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
hlist_add_head(&h->hnode, &hash[bucket]);
}
}
old_size = nf_conntrack_htable_size;
old_vmalloced = init_net.ct.hash_vmalloc;
old_hash = init_net.ct.hash;
nf_conntrack_htable_size = hashsize;
init_net.ct.hash_vmalloc = vmalloced;
init_net.ct.hash = hash;
nf_conntrack_hash_rnd = rnd;
spin_unlock_bh(&nf_conntrack_lock);
nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
return 0;
}
EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
&nf_conntrack_htable_size, 0600);
static int nf_conntrack_init_init_net(void)
{
int max_factor = 8;
int ret;
/* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB
* machine has 512 buckets. >= 1GB machines have 16384 buckets. */
if (!nf_conntrack_htable_size) {
nf_conntrack_htable_size
= (((num_physpages << PAGE_SHIFT) / 16384)
/ sizeof(struct hlist_head));
if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
nf_conntrack_htable_size = 16384;
if (nf_conntrack_htable_size < 32)
nf_conntrack_htable_size = 32;
/* Use a max. factor of four by default to get the same max as
* with the old struct list_heads. When a table size is given
* we use the old value of 8 to avoid reducing the max.
* entries. */
max_factor = 4;
}
nf_conntrack_max = max_factor * nf_conntrack_htable_size;
printk("nf_conntrack version %s (%u buckets, %d max)\n",
NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
nf_conntrack_max);
nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
sizeof(struct nf_conn),
0, 0, NULL);
if (!nf_conntrack_cachep) {
printk(KERN_ERR "Unable to create nf_conn slab cache\n");
ret = -ENOMEM;
goto err_cache;
}
ret = nf_conntrack_proto_init();
if (ret < 0)
goto err_proto;
ret = nf_conntrack_helper_init();
if (ret < 0)
goto err_helper;
return 0;
err_helper:
nf_conntrack_proto_fini();
err_proto:
kmem_cache_destroy(nf_conntrack_cachep);
err_cache:
return ret;
}
static int nf_conntrack_init_net(struct net *net)
{
int ret;
atomic_set(&net->ct.count, 0);
INIT_HLIST_HEAD(&net->ct.unconfirmed);
net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
if (!net->ct.stat) {
ret = -ENOMEM;
goto err_stat;
}
ret = nf_conntrack_ecache_init(net);
if (ret < 0)
goto err_ecache;
net->ct.hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
&net->ct.hash_vmalloc);
if (!net->ct.hash) {
ret = -ENOMEM;
printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
goto err_hash;
}
ret = nf_conntrack_expect_init(net);
if (ret < 0)
goto err_expect;
ret = nf_conntrack_acct_init(net);
if (ret < 0)
goto err_acct;
/* Set up fake conntrack:
- to never be deleted, not in any hashes */
#ifdef CONFIG_NET_NS
nf_conntrack_untracked.ct_net = &init_net;
#endif
atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
/* - and look it like as a confirmed connection */
set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
return 0;
err_acct:
nf_conntrack_expect_fini(net);
err_expect:
nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
nf_conntrack_htable_size);
err_hash:
nf_conntrack_ecache_fini(net);
err_ecache:
free_percpu(net->ct.stat);
err_stat:
return ret;
}
int nf_conntrack_init(struct net *net)
{
int ret;
if (net_eq(net, &init_net)) {
ret = nf_conntrack_init_init_net();
if (ret < 0)
goto out_init_net;
}
ret = nf_conntrack_init_net(net);
if (ret < 0)
goto out_net;
if (net_eq(net, &init_net)) {
/* For use by REJECT target */
rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
}
return 0;
out_net:
if (net_eq(net, &init_net))
nf_conntrack_cleanup_init_net();
out_init_net:
return ret;
}