diff options
Diffstat (limited to 'net/netfilter/nf_conntrack_core.c')
| -rw-r--r-- | net/netfilter/nf_conntrack_core.c | 1280 |
1 files changed, 1280 insertions, 0 deletions
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c new file mode 100644 index 0000000..233fdd2 --- /dev/null +++ b/net/netfilter/nf_conntrack_core.c @@ -0,0 +1,1280 @@ +/* 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); + + __nf_conntrack_hash_insert(ct, hash, repl_hash); +} +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; +} |
