/* 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 * (C) 2003,2004 USAGI/WIDE Project * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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); } 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 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(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); /* 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, &nf_conntrack_hash[hash], hnode) { if (nf_ct_tuple_equal(tuple, &h->tuple)) { NF_CT_STAT_INC(found); local_bh_enable(); return h; } NF_CT_STAT_INC(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(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); /* 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, &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_bh(); return 1; } NF_CT_STAT_INC(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(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, 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(&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); } } ct = kmem_cache_zalloc(nf_conntrack_cachep, gfp); if (ct == NULL) { pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n"); atomic_dec(&nf_conntrack_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); 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); nf_ct_ext_free(ct); kmem_cache_free(nf_conntrack_cachep, ct); atomic_dec(&nf_conntrack_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(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(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(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(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(new); } /* Overload tuple linked list to put us in unconfirmed list. */ hlist_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode, &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 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); 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, skb); } 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 #include #include /* 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(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(); nf_conntrack_acct_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; ret = nf_conntrack_acct_init(); if (ret < 0) goto out_fini_helper; /* 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_helper: nf_conntrack_helper_fini(); 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; }