| /* 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> |
| |
| #define NF_CONNTRACK_VERSION "0.5.0" |
| |
| DEFINE_SPINLOCK(nf_conntrack_lock); |
| EXPORT_SYMBOL_GPL(nf_conntrack_lock); |
| |
| /* nf_conntrack_standalone needs this */ |
| atomic_t nf_conntrack_count = ATOMIC_INIT(0); |
| EXPORT_SYMBOL_GPL(nf_conntrack_count); |
| |
| 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 hlist_head *nf_conntrack_hash __read_mostly; |
| EXPORT_SYMBOL_GPL(nf_conntrack_hash); |
| |
| struct nf_conn nf_conntrack_untracked __read_mostly; |
| EXPORT_SYMBOL_GPL(nf_conntrack_untracked); |
| |
| unsigned int nf_ct_log_invalid __read_mostly; |
| HLIST_HEAD(unconfirmed); |
| static int nf_conntrack_vmalloc __read_mostly; |
| static struct kmem_cache *nf_conntrack_cachep __read_mostly; |
| |
| DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat); |
| EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat); |
| |
| 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); |
| } |
| |
| int |
| 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) |
| { |
| NF_CT_TUPLE_U_BLANK(tuple); |
| |
| tuple->src.l3num = l3num; |
| if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) |
| return 0; |
| |
| 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); |
| |
| int 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 0; |
| } |
| |
| 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); |
| |
| int |
| 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) |
| { |
| NF_CT_TUPLE_U_BLANK(inverse); |
| |
| inverse->src.l3num = orig->src.l3num; |
| if (l3proto->invert_tuple(inverse, orig) == 0) |
| return 0; |
| |
| 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 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(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num, |
| ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum); |
| if (l4proto && l4proto->destroy) |
| l4proto->destroy(ct); |
| |
| nf_ct_ext_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(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 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(delete_list); |
| clean_from_lists(ct); |
| spin_unlock_bh(&nf_conntrack_lock); |
| nf_ct_put(ct); |
| } |
| |
| struct nf_conntrack_tuple_hash * |
| __nf_conntrack_find(const struct nf_conntrack_tuple *tuple) |
| { |
| struct nf_conntrack_tuple_hash *h; |
| struct hlist_node *n; |
| unsigned int hash = hash_conntrack(tuple); |
| |
| hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash], hnode) { |
| if (nf_ct_tuple_equal(tuple, &h->tuple)) { |
| NF_CT_STAT_INC(found); |
| return h; |
| } |
| NF_CT_STAT_INC(searched); |
| } |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(__nf_conntrack_find); |
| |
| /* Find a connection corresponding to a tuple. */ |
| struct nf_conntrack_tuple_hash * |
| nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple) |
| { |
| struct nf_conntrack_tuple_hash *h; |
| struct nf_conn *ct; |
| |
| rcu_read_lock(); |
| h = __nf_conntrack_find(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) |
| { |
| hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode, |
| &nf_conntrack_hash[hash]); |
| hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode, |
| &nf_conntrack_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; |
| |
| ct = nf_ct_get(skb, &ctinfo); |
| |
| /* 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, &nf_conntrack_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, &nf_conntrack_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(insert); |
| spin_unlock_bh(&nf_conntrack_lock); |
| help = nfct_help(ct); |
| if (help && help->helper) |
| nf_conntrack_event_cache(IPCT_HELPER, skb); |
| #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, skb); |
| #endif |
| nf_conntrack_event_cache(master_ct(ct) ? |
| IPCT_RELATED : IPCT_NEW, skb); |
| return NF_ACCEPT; |
| |
| out: |
| NF_CT_STAT_INC(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 nf_conntrack_tuple_hash *h; |
| struct hlist_node *n; |
| unsigned int hash = hash_conntrack(tuple); |
| |
| rcu_read_lock(); |
| hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash], hnode) { |
| if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack && |
| nf_ct_tuple_equal(tuple, &h->tuple)) { |
| NF_CT_STAT_INC(found); |
| rcu_read_unlock(); |
| return 1; |
| } |
| NF_CT_STAT_INC(searched); |
| } |
| rcu_read_unlock(); |
| |
| 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(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, &nf_conntrack_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(early_drop); |
| } |
| nf_ct_put(ct); |
| return dropped; |
| } |
| |
| struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig, |
| const struct nf_conntrack_tuple *repl) |
| { |
| struct nf_conn *conntrack = 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(&nf_conntrack_count); |
| |
| if (nf_conntrack_max && |
| unlikely(atomic_read(&nf_conntrack_count) > nf_conntrack_max)) { |
| unsigned int hash = hash_conntrack(orig); |
| if (!early_drop(hash)) { |
| atomic_dec(&nf_conntrack_count); |
| if (net_ratelimit()) |
| printk(KERN_WARNING |
| "nf_conntrack: table full, dropping" |
| " packet.\n"); |
| return ERR_PTR(-ENOMEM); |
| } |
| } |
| |
| conntrack = kmem_cache_zalloc(nf_conntrack_cachep, GFP_ATOMIC); |
| if (conntrack == NULL) { |
| pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n"); |
| atomic_dec(&nf_conntrack_count); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| atomic_set(&conntrack->ct_general.use, 1); |
| conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; |
| conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; |
| /* Don't set timer yet: wait for confirmation */ |
| setup_timer(&conntrack->timeout, death_by_timeout, |
| (unsigned long)conntrack); |
| INIT_RCU_HEAD(&conntrack->rcu); |
| |
| return conntrack; |
| } |
| 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); |
| |
| nf_ct_ext_free(ct); |
| kmem_cache_free(nf_conntrack_cachep, ct); |
| atomic_dec(&nf_conntrack_count); |
| } |
| |
| void nf_conntrack_free(struct nf_conn *conntrack) |
| { |
| call_rcu(&conntrack->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(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 *conntrack; |
| 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; |
| } |
| |
| conntrack = nf_conntrack_alloc(tuple, &repl_tuple); |
| if (conntrack == NULL || IS_ERR(conntrack)) { |
| pr_debug("Can't allocate conntrack.\n"); |
| return (struct nf_conntrack_tuple_hash *)conntrack; |
| } |
| |
| if (!l4proto->new(conntrack, skb, dataoff)) { |
| nf_conntrack_free(conntrack); |
| pr_debug("init conntrack: can't track with proto module\n"); |
| return NULL; |
| } |
| |
| spin_lock_bh(&nf_conntrack_lock); |
| exp = nf_ct_find_expectation(tuple); |
| if (exp) { |
| pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", |
| conntrack, exp); |
| /* Welcome, Mr. Bond. We've been expecting you... */ |
| __set_bit(IPS_EXPECTED_BIT, &conntrack->status); |
| conntrack->master = exp->master; |
| if (exp->helper) { |
| help = nf_ct_helper_ext_add(conntrack, GFP_ATOMIC); |
| if (help) |
| rcu_assign_pointer(help->helper, exp->helper); |
| } |
| |
| #ifdef CONFIG_NF_CONNTRACK_MARK |
| conntrack->mark = exp->master->mark; |
| #endif |
| #ifdef CONFIG_NF_CONNTRACK_SECMARK |
| conntrack->secmark = exp->master->secmark; |
| #endif |
| nf_conntrack_get(&conntrack->master->ct_general); |
| NF_CT_STAT_INC(expect_new); |
| } else { |
| struct nf_conntrack_helper *helper; |
| |
| helper = __nf_ct_helper_find(&repl_tuple); |
| if (helper) { |
| help = nf_ct_helper_ext_add(conntrack, GFP_ATOMIC); |
| if (help) |
| rcu_assign_pointer(help->helper, helper); |
| } |
| NF_CT_STAT_INC(new); |
| } |
| |
| /* Overload tuple linked list to put us in unconfirmed list. */ |
| hlist_add_head(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].hnode, |
| &unconfirmed); |
| |
| spin_unlock_bh(&nf_conntrack_lock); |
| |
| if (exp) { |
| if (exp->expectfn) |
| exp->expectfn(conntrack, exp); |
| nf_ct_expect_put(exp); |
| } |
| |
| return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL]; |
| } |
| |
| /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ |
| static inline struct nf_conn * |
| resolve_normal_ct(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(&tuple); |
| if (!h) { |
| h = init_conntrack(&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(int 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(ignore); |
| return NF_ACCEPT; |
| } |
| |
| /* rcu_read_lock()ed by nf_hook_slow */ |
| l3proto = __nf_ct_l3proto_find((u_int16_t)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(error); |
| NF_CT_STAT_INC_ATOMIC(invalid); |
| return -ret; |
| } |
| |
| l4proto = __nf_ct_l4proto_find((u_int16_t)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(skb, dataoff, &ctinfo, pf, hooknum)) <= 0) { |
| NF_CT_STAT_INC_ATOMIC(error); |
| NF_CT_STAT_INC_ATOMIC(invalid); |
| return -ret; |
| } |
| |
| ct = resolve_normal_ct(skb, dataoff, pf, protonum, l3proto, l4proto, |
| &set_reply, &ctinfo); |
| if (!ct) { |
| /* Not valid part of a connection */ |
| NF_CT_STAT_INC_ATOMIC(invalid); |
| return NF_ACCEPT; |
| } |
| |
| if (IS_ERR(ct)) { |
| /* Too stressed to deal. */ |
| NF_CT_STAT_INC_ATOMIC(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(invalid); |
| return -ret; |
| } |
| |
| if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) |
| nf_conntrack_event_cache(IPCT_STATUS, skb); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_in); |
| |
| int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, |
| const struct nf_conntrack_tuple *orig) |
| { |
| int 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 && help->expecting != 0)) |
| 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: |
| #ifdef CONFIG_NF_CT_ACCT |
| if (do_acct) { |
| ct->counters[CTINFO2DIR(ctinfo)].packets++; |
| ct->counters[CTINFO2DIR(ctinfo)].bytes += |
| skb->len - skb_network_offset(skb); |
| |
| if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000) |
| || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000)) |
| event |= IPCT_COUNTER_FILLING; |
| } |
| #endif |
| |
| spin_unlock_bh(&nf_conntrack_lock); |
| |
| /* must be unlocked when calling event cache */ |
| if (event) |
| nf_conntrack_event_cache(event, skb); |
| } |
| EXPORT_SYMBOL_GPL(__nf_ct_refresh_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); |
| } |
| |
| static inline int |
| do_iter(const struct nf_conntrack_tuple_hash *i, |
| int (*iter)(struct nf_conn *i, void *data), |
| void *data) |
| { |
| return iter(nf_ct_tuplehash_to_ctrack(i), data); |
| } |
| |
| /* Bring out ya dead! */ |
| static struct nf_conn * |
| get_next_corpse(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, &nf_conntrack_hash[*bucket], hnode) { |
| ct = nf_ct_tuplehash_to_ctrack(h); |
| if (iter(ct, data)) |
| goto found; |
| } |
| } |
| hlist_for_each_entry(h, n, &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(int (*iter)(struct nf_conn *i, void *data), void *data) |
| { |
| struct nf_conn *ct; |
| unsigned int bucket = 0; |
| |
| while ((ct = get_next_corpse(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(void) |
| { |
| nf_ct_iterate_cleanup(kill_all, NULL); |
| } |
| EXPORT_SYMBOL_GPL(nf_conntrack_flush); |
| |
| /* Mishearing the voices in his head, our hero wonders how he's |
| supposed to kill the mall. */ |
| void nf_conntrack_cleanup(void) |
| { |
| 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_ct_event_cache_flush(); |
| i_see_dead_people: |
| nf_conntrack_flush(); |
| if (atomic_read(&nf_conntrack_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(); |
| |
| rcu_assign_pointer(nf_ct_destroy, NULL); |
| |
| kmem_cache_destroy(nf_conntrack_cachep); |
| nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc, |
| nf_conntrack_htable_size); |
| |
| nf_conntrack_proto_fini(); |
| nf_conntrack_helper_fini(); |
| nf_conntrack_expect_fini(); |
| } |
| |
| 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(&nf_conntrack_hash[i])) { |
| h = hlist_entry(nf_conntrack_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 = nf_conntrack_vmalloc; |
| old_hash = nf_conntrack_hash; |
| |
| nf_conntrack_htable_size = hashsize; |
| nf_conntrack_vmalloc = vmalloced; |
| nf_conntrack_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); |
| |
| int __init nf_conntrack_init(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_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, |
| &nf_conntrack_vmalloc); |
| if (!nf_conntrack_hash) { |
| printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); |
| goto err_out; |
| } |
| |
| 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"); |
| goto err_free_hash; |
| } |
| |
| ret = nf_conntrack_proto_init(); |
| if (ret < 0) |
| goto err_free_conntrack_slab; |
| |
| ret = nf_conntrack_expect_init(); |
| if (ret < 0) |
| goto out_fini_proto; |
| |
| ret = nf_conntrack_helper_init(); |
| if (ret < 0) |
| goto out_fini_expect; |
| |
| /* For use by REJECT target */ |
| rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach); |
| rcu_assign_pointer(nf_ct_destroy, destroy_conntrack); |
| |
| /* Set up fake conntrack: |
| - to never be deleted, not in any hashes */ |
| 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 ret; |
| |
| out_fini_expect: |
| nf_conntrack_expect_fini(); |
| out_fini_proto: |
| nf_conntrack_proto_fini(); |
| err_free_conntrack_slab: |
| kmem_cache_destroy(nf_conntrack_cachep); |
| err_free_hash: |
| nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc, |
| nf_conntrack_htable_size); |
| err_out: |
| return -ENOMEM; |
| } |