/* 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 * (C) 2005-2012 Patrick McHardy * * 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. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define NF_CONNTRACK_VERSION "0.5.0" int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct, enum nf_nat_manip_type manip, const struct nlattr *attr) __read_mostly; EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook); __cacheline_aligned_in_smp spinlock_t nf_conntrack_locks[CONNTRACK_LOCKS]; EXPORT_SYMBOL_GPL(nf_conntrack_locks); __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock); EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock); struct hlist_nulls_head *nf_conntrack_hash __read_mostly; EXPORT_SYMBOL_GPL(nf_conntrack_hash); struct conntrack_gc_work { struct delayed_work dwork; u32 last_bucket; bool exiting; long next_gc_run; }; static __read_mostly struct kmem_cache *nf_conntrack_cachep; static __read_mostly spinlock_t nf_conntrack_locks_all_lock; static __read_mostly DEFINE_SPINLOCK(nf_conntrack_locks_all_lock); static __read_mostly bool nf_conntrack_locks_all; /* every gc cycle scans at most 1/GC_MAX_BUCKETS_DIV part of table */ #define GC_MAX_BUCKETS_DIV 128u /* upper bound of full table scan */ #define GC_MAX_SCAN_JIFFIES (16u * HZ) /* desired ratio of entries found to be expired */ #define GC_EVICT_RATIO 50u static struct conntrack_gc_work conntrack_gc_work; void nf_conntrack_lock(spinlock_t *lock) __acquires(lock) { spin_lock(lock); while (unlikely(nf_conntrack_locks_all)) { spin_unlock(lock); /* * Order the 'nf_conntrack_locks_all' load vs. the * spin_unlock_wait() loads below, to ensure * that 'nf_conntrack_locks_all_lock' is indeed held: */ smp_rmb(); /* spin_lock(&nf_conntrack_locks_all_lock) */ spin_unlock_wait(&nf_conntrack_locks_all_lock); spin_lock(lock); } } EXPORT_SYMBOL_GPL(nf_conntrack_lock); static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2) { h1 %= CONNTRACK_LOCKS; h2 %= CONNTRACK_LOCKS; spin_unlock(&nf_conntrack_locks[h1]); if (h1 != h2) spin_unlock(&nf_conntrack_locks[h2]); } /* return true if we need to recompute hashes (in case hash table was resized) */ static bool nf_conntrack_double_lock(struct net *net, unsigned int h1, unsigned int h2, unsigned int sequence) { h1 %= CONNTRACK_LOCKS; h2 %= CONNTRACK_LOCKS; if (h1 <= h2) { nf_conntrack_lock(&nf_conntrack_locks[h1]); if (h1 != h2) spin_lock_nested(&nf_conntrack_locks[h2], SINGLE_DEPTH_NESTING); } else { nf_conntrack_lock(&nf_conntrack_locks[h2]); spin_lock_nested(&nf_conntrack_locks[h1], SINGLE_DEPTH_NESTING); } if (read_seqcount_retry(&nf_conntrack_generation, sequence)) { nf_conntrack_double_unlock(h1, h2); return true; } return false; } static void nf_conntrack_all_lock(void) { int i; spin_lock(&nf_conntrack_locks_all_lock); nf_conntrack_locks_all = true; /* * Order the above store of 'nf_conntrack_locks_all' against * the spin_unlock_wait() loads below, such that if * nf_conntrack_lock() observes 'nf_conntrack_locks_all' * we must observe nf_conntrack_locks[] held: */ smp_mb(); /* spin_lock(&nf_conntrack_locks_all_lock) */ for (i = 0; i < CONNTRACK_LOCKS; i++) { spin_unlock_wait(&nf_conntrack_locks[i]); } } static void nf_conntrack_all_unlock(void) { /* * All prior stores must be complete before we clear * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock() * might observe the false value but not the entire * critical section: */ smp_store_release(&nf_conntrack_locks_all, false); spin_unlock(&nf_conntrack_locks_all_lock); } unsigned int nf_conntrack_htable_size __read_mostly; EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); unsigned int nf_conntrack_max __read_mostly; seqcount_t nf_conntrack_generation __read_mostly; /* nf_conn must be 8 bytes aligned, as the 3 LSB bits are used * for the nfctinfo. We cheat by (ab)using the PER CPU cache line * alignment to enforce this. */ DEFINE_PER_CPU_ALIGNED(struct nf_conn, nf_conntrack_untracked); EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked); static unsigned int nf_conntrack_hash_rnd __read_mostly; static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, const struct net *net) { unsigned int n; u32 seed; get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd)); /* 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. */ seed = nf_conntrack_hash_rnd ^ net_hash_mix(net); n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); return jhash2((u32 *)tuple, n, seed ^ (((__force __u16)tuple->dst.u.all << 16) | tuple->dst.protonum)); } static u32 scale_hash(u32 hash) { return reciprocal_scale(hash, nf_conntrack_htable_size); } static u32 __hash_conntrack(const struct net *net, const struct nf_conntrack_tuple *tuple, unsigned int size) { return reciprocal_scale(hash_conntrack_raw(tuple, net), size); } static u32 hash_conntrack(const struct net *net, const struct nf_conntrack_tuple *tuple) { return scale_hash(hash_conntrack_raw(tuple, net)); } 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 net *net, 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, net, 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 net *net, 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, net, 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_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); /* Destroy all pending expectations */ nf_ct_remove_expectations(ct); } /* must be called with local_bh_disable */ static void nf_ct_add_to_dying_list(struct nf_conn *ct) { struct ct_pcpu *pcpu; /* add this conntrack to the (per cpu) dying list */ ct->cpu = smp_processor_id(); pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu); spin_lock(&pcpu->lock); hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, &pcpu->dying); spin_unlock(&pcpu->lock); } /* must be called with local_bh_disable */ static void nf_ct_add_to_unconfirmed_list(struct nf_conn *ct) { struct ct_pcpu *pcpu; /* add this conntrack to the (per cpu) unconfirmed list */ ct->cpu = smp_processor_id(); pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu); spin_lock(&pcpu->lock); hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, &pcpu->unconfirmed); spin_unlock(&pcpu->lock); } /* must be called with local_bh_disable */ static void nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn *ct) { struct ct_pcpu *pcpu; /* We overload first tuple to link into unconfirmed or dying list.*/ pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu); spin_lock(&pcpu->lock); BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); spin_unlock(&pcpu->lock); } #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK) /* Released via destroy_conntrack() */ struct nf_conn *nf_ct_tmpl_alloc(struct net *net, const struct nf_conntrack_zone *zone, gfp_t flags) { struct nf_conn *tmpl, *p; if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) { tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags); if (!tmpl) return NULL; p = tmpl; tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p); if (tmpl != p) { tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p); tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p; } } else { tmpl = kzalloc(sizeof(*tmpl), flags); if (!tmpl) return NULL; } tmpl->status = IPS_TEMPLATE; write_pnet(&tmpl->ct_net, net); nf_ct_zone_add(tmpl, zone); atomic_set(&tmpl->ct_general.use, 0); return tmpl; } EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc); void nf_ct_tmpl_free(struct nf_conn *tmpl) { nf_ct_ext_destroy(tmpl); nf_ct_ext_free(tmpl); if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) kfree((char *)tmpl - tmpl->proto.tmpl_padto); else kfree(tmpl); } EXPORT_SYMBOL_GPL(nf_ct_tmpl_free); 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); if (unlikely(nf_ct_is_template(ct))) { nf_ct_tmpl_free(ct); return; } rcu_read_lock(); l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); if (l4proto->destroy) l4proto->destroy(ct); rcu_read_unlock(); local_bh_disable(); /* 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); nf_ct_del_from_dying_or_unconfirmed_list(ct); local_bh_enable(); 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 nf_ct_delete_from_lists(struct nf_conn *ct) { struct net *net = nf_ct_net(ct); unsigned int hash, reply_hash; unsigned int sequence; nf_ct_helper_destroy(ct); local_bh_disable(); do { sequence = read_seqcount_begin(&nf_conntrack_generation); hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); reply_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); clean_from_lists(ct); nf_conntrack_double_unlock(hash, reply_hash); nf_ct_add_to_dying_list(ct); local_bh_enable(); } bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report) { struct nf_conn_tstamp *tstamp; if (test_and_set_bit(IPS_DYING_BIT, &ct->status)) return false; tstamp = nf_conn_tstamp_find(ct); if (tstamp && tstamp->stop == 0) tstamp->stop = ktime_get_real_ns(); if (nf_conntrack_event_report(IPCT_DESTROY, ct, portid, report) < 0) { /* destroy event was not delivered. nf_ct_put will * be done by event cache worker on redelivery. */ nf_ct_delete_from_lists(ct); nf_conntrack_ecache_delayed_work(nf_ct_net(ct)); return false; } nf_conntrack_ecache_work(nf_ct_net(ct)); nf_ct_delete_from_lists(ct); nf_ct_put(ct); return true; } EXPORT_SYMBOL_GPL(nf_ct_delete); static inline bool nf_ct_key_equal(struct nf_conntrack_tuple_hash *h, const struct nf_conntrack_tuple *tuple, const struct nf_conntrack_zone *zone, const struct net *net) { struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); /* A conntrack can be recreated with the equal tuple, * so we need to check that the conntrack is confirmed */ return nf_ct_tuple_equal(tuple, &h->tuple) && nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) && nf_ct_is_confirmed(ct) && net_eq(net, nf_ct_net(ct)); } /* caller must hold rcu readlock and none of the nf_conntrack_locks */ static void nf_ct_gc_expired(struct nf_conn *ct) { if (!atomic_inc_not_zero(&ct->ct_general.use)) return; if (nf_ct_should_gc(ct)) nf_ct_kill(ct); nf_ct_put(ct); } /* * Warning : * - Caller must take a reference on returned object * and recheck nf_ct_tuple_equal(tuple, &h->tuple) */ static struct nf_conntrack_tuple_hash * ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone, const struct nf_conntrack_tuple *tuple, u32 hash) { struct nf_conntrack_tuple_hash *h; struct hlist_nulls_head *ct_hash; struct hlist_nulls_node *n; unsigned int bucket, hsize; begin: nf_conntrack_get_ht(&ct_hash, &hsize); bucket = reciprocal_scale(hash, hsize); hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) { struct nf_conn *ct; ct = nf_ct_tuplehash_to_ctrack(h); if (nf_ct_is_expired(ct)) { nf_ct_gc_expired(ct); continue; } if (nf_ct_is_dying(ct)) continue; if (nf_ct_key_equal(h, tuple, zone, net)) return h; } /* * if the nulls value we got at the end of this lookup is * not the expected one, we must restart lookup. * We probably met an item that was moved to another chain. */ if (get_nulls_value(n) != bucket) { NF_CT_STAT_INC_ATOMIC(net, search_restart); goto begin; } return NULL; } /* Find a connection corresponding to a tuple. */ static struct nf_conntrack_tuple_hash * __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone, const struct nf_conntrack_tuple *tuple, u32 hash) { struct nf_conntrack_tuple_hash *h; struct nf_conn *ct; rcu_read_lock(); begin: h = ____nf_conntrack_find(net, zone, tuple, hash); if (h) { ct = nf_ct_tuplehash_to_ctrack(h); if (unlikely(nf_ct_is_dying(ct) || !atomic_inc_not_zero(&ct->ct_general.use))) h = NULL; else { if (unlikely(!nf_ct_key_equal(h, tuple, zone, net))) { nf_ct_put(ct); goto begin; } } } rcu_read_unlock(); return h; } struct nf_conntrack_tuple_hash * nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone, const struct nf_conntrack_tuple *tuple) { return __nf_conntrack_find_get(net, zone, tuple, hash_conntrack_raw(tuple, net)); } EXPORT_SYMBOL_GPL(nf_conntrack_find_get); static void __nf_conntrack_hash_insert(struct nf_conn *ct, unsigned int hash, unsigned int reply_hash) { hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, &nf_conntrack_hash[hash]); hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, &nf_conntrack_hash[reply_hash]); } int nf_conntrack_hash_check_insert(struct nf_conn *ct) { const struct nf_conntrack_zone *zone; struct net *net = nf_ct_net(ct); unsigned int hash, reply_hash; struct nf_conntrack_tuple_hash *h; struct hlist_nulls_node *n; unsigned int sequence; zone = nf_ct_zone(ct); local_bh_disable(); do { sequence = read_seqcount_begin(&nf_conntrack_generation); hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); reply_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); /* See if there's one in the list already, including reverse */ hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, zone, net)) goto out; hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, zone, net)) goto out; smp_wmb(); /* The caller holds a reference to this object */ atomic_set(&ct->ct_general.use, 2); __nf_conntrack_hash_insert(ct, hash, reply_hash); nf_conntrack_double_unlock(hash, reply_hash); NF_CT_STAT_INC(net, insert); local_bh_enable(); return 0; out: nf_conntrack_double_unlock(hash, reply_hash); NF_CT_STAT_INC(net, insert_failed); local_bh_enable(); return -EEXIST; } EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert); static inline void nf_ct_acct_update(struct nf_conn *ct, enum ip_conntrack_info ctinfo, unsigned int len) { struct nf_conn_acct *acct; acct = nf_conn_acct_find(ct); if (acct) { struct nf_conn_counter *counter = acct->counter; atomic64_inc(&counter[CTINFO2DIR(ctinfo)].packets); atomic64_add(len, &counter[CTINFO2DIR(ctinfo)].bytes); } } static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo, const struct nf_conn *loser_ct) { struct nf_conn_acct *acct; acct = nf_conn_acct_find(loser_ct); if (acct) { struct nf_conn_counter *counter = acct->counter; unsigned int bytes; /* u32 should be fine since we must have seen one packet. */ bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes); nf_ct_acct_update(ct, ctinfo, bytes); } } /* Resolve race on insertion if this protocol allows this. */ static int nf_ct_resolve_clash(struct net *net, struct sk_buff *skb, enum ip_conntrack_info ctinfo, struct nf_conntrack_tuple_hash *h) { /* This is the conntrack entry already in hashes that won race. */ struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); struct nf_conntrack_l4proto *l4proto; l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); if (l4proto->allow_clash && !nfct_nat(ct) && !nf_ct_is_dying(ct) && atomic_inc_not_zero(&ct->ct_general.use)) { enum ip_conntrack_info oldinfo; struct nf_conn *loser_ct = nf_ct_get(skb, &oldinfo); nf_ct_acct_merge(ct, ctinfo, loser_ct); nf_conntrack_put(&loser_ct->ct_general); nf_ct_set(skb, ct, oldinfo); return NF_ACCEPT; } NF_CT_STAT_INC(net, drop); return NF_DROP; } /* Confirm a connection given skb; places it in hash table */ int __nf_conntrack_confirm(struct sk_buff *skb) { const struct nf_conntrack_zone *zone; unsigned int hash, reply_hash; struct nf_conntrack_tuple_hash *h; struct nf_conn *ct; struct nf_conn_help *help; struct nf_conn_tstamp *tstamp; struct hlist_nulls_node *n; enum ip_conntrack_info ctinfo; struct net *net; unsigned int sequence; int ret = NF_DROP; 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; zone = nf_ct_zone(ct); local_bh_disable(); do { sequence = read_seqcount_begin(&nf_conntrack_generation); /* reuse the hash saved before */ hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev; hash = scale_hash(hash); reply_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); /* 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 no one else could have * confirmed us. */ NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); pr_debug("Confirming conntrack %p\n", ct); /* We have to check the DYING flag after unlink to prevent * a race against nf_ct_get_next_corpse() possibly called from * user context, else we insert an already 'dead' hash, blocking * further use of that particular connection -JM. */ nf_ct_del_from_dying_or_unconfirmed_list(ct); if (unlikely(nf_ct_is_dying(ct))) { nf_ct_add_to_dying_list(ct); goto dying; } /* 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_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, zone, net)) goto out; hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, zone, net)) goto out; /* Timer relative to confirmation time, not original setting time, otherwise we'd get timer wrap in weird delay cases. */ ct->timeout += nfct_time_stamp; atomic_inc(&ct->ct_general.use); ct->status |= IPS_CONFIRMED; /* set conntrack timestamp, if enabled. */ tstamp = nf_conn_tstamp_find(ct); if (tstamp) { if (skb->tstamp == 0) __net_timestamp(skb); tstamp->start = ktime_to_ns(skb->tstamp); } /* Since the lookup is lockless, hash insertion must be done after * starting the timer and setting the CONFIRMED bit. The RCU barriers * guarantee that no other CPU can find the conntrack before the above * stores are visible. */ __nf_conntrack_hash_insert(ct, hash, reply_hash); nf_conntrack_double_unlock(hash, reply_hash); local_bh_enable(); help = nfct_help(ct); if (help && help->helper) nf_conntrack_event_cache(IPCT_HELPER, ct); nf_conntrack_event_cache(master_ct(ct) ? IPCT_RELATED : IPCT_NEW, ct); return NF_ACCEPT; out: nf_ct_add_to_dying_list(ct); ret = nf_ct_resolve_clash(net, skb, ctinfo, h); dying: nf_conntrack_double_unlock(hash, reply_hash); NF_CT_STAT_INC(net, insert_failed); local_bh_enable(); return ret; } 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); const struct nf_conntrack_zone *zone; struct nf_conntrack_tuple_hash *h; struct hlist_nulls_head *ct_hash; unsigned int hash, hsize; struct hlist_nulls_node *n; struct nf_conn *ct; zone = nf_ct_zone(ignored_conntrack); rcu_read_lock(); begin: nf_conntrack_get_ht(&ct_hash, &hsize); hash = __hash_conntrack(net, tuple, hsize); hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) { ct = nf_ct_tuplehash_to_ctrack(h); if (ct == ignored_conntrack) continue; if (nf_ct_is_expired(ct)) { nf_ct_gc_expired(ct); continue; } if (nf_ct_key_equal(h, tuple, zone, net)) { NF_CT_STAT_INC_ATOMIC(net, found); rcu_read_unlock(); return 1; } } if (get_nulls_value(n) != hash) { NF_CT_STAT_INC_ATOMIC(net, search_restart); goto begin; } 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 unsigned int early_drop_list(struct net *net, struct hlist_nulls_head *head) { struct nf_conntrack_tuple_hash *h; struct hlist_nulls_node *n; unsigned int drops = 0; struct nf_conn *tmp; hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) { tmp = nf_ct_tuplehash_to_ctrack(h); if (nf_ct_is_expired(tmp)) { nf_ct_gc_expired(tmp); continue; } if (test_bit(IPS_ASSURED_BIT, &tmp->status) || !net_eq(nf_ct_net(tmp), net) || nf_ct_is_dying(tmp)) continue; if (!atomic_inc_not_zero(&tmp->ct_general.use)) continue; /* kill only if still in same netns -- might have moved due to * SLAB_DESTROY_BY_RCU rules. * * We steal the timer reference. If that fails timer has * already fired or someone else deleted it. Just drop ref * and move to next entry. */ if (net_eq(nf_ct_net(tmp), net) && nf_ct_is_confirmed(tmp) && nf_ct_delete(tmp, 0, 0)) drops++; nf_ct_put(tmp); } return drops; } static noinline int early_drop(struct net *net, unsigned int _hash) { unsigned int i; for (i = 0; i < NF_CT_EVICTION_RANGE; i++) { struct hlist_nulls_head *ct_hash; unsigned int hash, hsize, drops; rcu_read_lock(); nf_conntrack_get_ht(&ct_hash, &hsize); hash = reciprocal_scale(_hash++, hsize); drops = early_drop_list(net, &ct_hash[hash]); rcu_read_unlock(); if (drops) { NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops); return true; } } return false; } static void gc_worker(struct work_struct *work) { unsigned int min_interval = max(HZ / GC_MAX_BUCKETS_DIV, 1u); unsigned int i, goal, buckets = 0, expired_count = 0; struct conntrack_gc_work *gc_work; unsigned int ratio, scanned = 0; unsigned long next_run; gc_work = container_of(work, struct conntrack_gc_work, dwork.work); goal = nf_conntrack_htable_size / GC_MAX_BUCKETS_DIV; i = gc_work->last_bucket; do { struct nf_conntrack_tuple_hash *h; struct hlist_nulls_head *ct_hash; struct hlist_nulls_node *n; unsigned int hashsz; struct nf_conn *tmp; i++; rcu_read_lock(); nf_conntrack_get_ht(&ct_hash, &hashsz); if (i >= hashsz) i = 0; hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) { tmp = nf_ct_tuplehash_to_ctrack(h); scanned++; if (nf_ct_is_expired(tmp)) { nf_ct_gc_expired(tmp); expired_count++; continue; } } /* could check get_nulls_value() here and restart if ct * was moved to another chain. But given gc is best-effort * we will just continue with next hash slot. */ rcu_read_unlock(); cond_resched_rcu_qs(); } while (++buckets < goal); if (gc_work->exiting) return; /* * Eviction will normally happen from the packet path, and not * from this gc worker. * * This worker is only here to reap expired entries when system went * idle after a busy period. * * The heuristics below are supposed to balance conflicting goals: * * 1. Minimize time until we notice a stale entry * 2. Maximize scan intervals to not waste cycles * * Normally, expire ratio will be close to 0. * * As soon as a sizeable fraction of the entries have expired * increase scan frequency. */ ratio = scanned ? expired_count * 100 / scanned : 0; if (ratio > GC_EVICT_RATIO) { gc_work->next_gc_run = min_interval; } else { unsigned int max = GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV; BUILD_BUG_ON((GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV) == 0); gc_work->next_gc_run += min_interval; if (gc_work->next_gc_run > max) gc_work->next_gc_run = max; } next_run = gc_work->next_gc_run; gc_work->last_bucket = i; queue_delayed_work(system_long_wq, &gc_work->dwork, next_run); } static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work) { INIT_DELAYED_WORK(&gc_work->dwork, gc_worker); gc_work->next_gc_run = HZ; gc_work->exiting = false; } static struct nf_conn * __nf_conntrack_alloc(struct net *net, const struct nf_conntrack_zone *zone, const struct nf_conntrack_tuple *orig, const struct nf_conntrack_tuple *repl, gfp_t gfp, u32 hash) { struct nf_conn *ct; /* 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)) { if (!early_drop(net, hash)) { atomic_dec(&net->ct.count); net_warn_ratelimited("nf_conntrack: table full, dropping packet\n"); return ERR_PTR(-ENOMEM); } } /* * Do not use kmem_cache_zalloc(), as this cache uses * SLAB_DESTROY_BY_RCU. */ ct = kmem_cache_alloc(nf_conntrack_cachep, gfp); if (ct == NULL) goto out; spin_lock_init(&ct->lock); ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; /* save hash for reusing when confirming */ *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash; ct->status = 0; write_pnet(&ct->ct_net, net); memset(&ct->__nfct_init_offset[0], 0, offsetof(struct nf_conn, proto) - offsetof(struct nf_conn, __nfct_init_offset[0])); nf_ct_zone_add(ct, zone); /* Because we use RCU lookups, we set ct_general.use to zero before * this is inserted in any list. */ atomic_set(&ct->ct_general.use, 0); return ct; out: atomic_dec(&net->ct.count); return ERR_PTR(-ENOMEM); } struct nf_conn *nf_conntrack_alloc(struct net *net, const struct nf_conntrack_zone *zone, const struct nf_conntrack_tuple *orig, const struct nf_conntrack_tuple *repl, gfp_t gfp) { return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0); } EXPORT_SYMBOL_GPL(nf_conntrack_alloc); void nf_conntrack_free(struct nf_conn *ct) { struct net *net = nf_ct_net(ct); /* A freed object has refcnt == 0, that's * the golden rule for SLAB_DESTROY_BY_RCU */ NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 0); nf_ct_ext_destroy(ct); nf_ct_ext_free(ct); kmem_cache_free(nf_conntrack_cachep, ct); smp_mb__before_atomic(); atomic_dec(&net->ct.count); } 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, struct nf_conn *tmpl, const struct nf_conntrack_tuple *tuple, struct nf_conntrack_l3proto *l3proto, struct nf_conntrack_l4proto *l4proto, struct sk_buff *skb, unsigned int dataoff, u32 hash) { struct nf_conn *ct; struct nf_conn_help *help; struct nf_conntrack_tuple repl_tuple; struct nf_conntrack_ecache *ecache; struct nf_conntrack_expect *exp = NULL; const struct nf_conntrack_zone *zone; struct nf_conn_timeout *timeout_ext; struct nf_conntrack_zone tmp; unsigned int *timeouts; if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { pr_debug("Can't invert tuple.\n"); return NULL; } zone = nf_ct_zone_tmpl(tmpl, skb, &tmp); ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC, hash); if (IS_ERR(ct)) return (struct nf_conntrack_tuple_hash *)ct; if (!nf_ct_add_synproxy(ct, tmpl)) { nf_conntrack_free(ct); return ERR_PTR(-ENOMEM); } timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL; if (timeout_ext) { timeouts = nf_ct_timeout_data(timeout_ext); if (unlikely(!timeouts)) timeouts = l4proto->get_timeouts(net); } else { timeouts = l4proto->get_timeouts(net); } if (!l4proto->new(ct, skb, dataoff, timeouts)) { nf_conntrack_free(ct); pr_debug("can't track with proto module\n"); return NULL; } if (timeout_ext) nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout), GFP_ATOMIC); nf_ct_acct_ext_add(ct, GFP_ATOMIC); nf_ct_tstamp_ext_add(ct, GFP_ATOMIC); nf_ct_labels_ext_add(ct); ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, ecache ? ecache->expmask : 0, GFP_ATOMIC); local_bh_disable(); if (net->ct.expect_count) { spin_lock(&nf_conntrack_expect_lock); exp = nf_ct_find_expectation(net, zone, tuple); if (exp) { pr_debug("expectation arrives ct=%p exp=%p\n", ct, exp); /* Welcome, Mr. Bond. We've been expecting you... */ __set_bit(IPS_EXPECTED_BIT, &ct->status); /* exp->master safe, refcnt bumped in nf_ct_find_expectation */ ct->master = exp->master; if (exp->helper) { help = nf_ct_helper_ext_add(ct, exp->helper, 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_CT_STAT_INC(net, expect_new); } spin_unlock(&nf_conntrack_expect_lock); } if (!exp) __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); /* Now it is inserted into the unconfirmed list, bump refcount */ nf_conntrack_get(&ct->ct_general); nf_ct_add_to_unconfirmed_list(ct); local_bh_enable(); 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 | ctinfo */ static inline struct nf_conn * resolve_normal_ct(struct net *net, struct nf_conn *tmpl, 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) { const struct nf_conntrack_zone *zone; struct nf_conntrack_tuple tuple; struct nf_conntrack_tuple_hash *h; struct nf_conntrack_zone tmp; struct nf_conn *ct; u32 hash; if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num, protonum, net, &tuple, l3proto, l4proto)) { pr_debug("Can't get tuple\n"); return NULL; } /* look for tuple match */ zone = nf_ct_zone_tmpl(tmpl, skb, &tmp); hash = hash_conntrack_raw(&tuple, net); h = __nf_conntrack_find_get(net, zone, &tuple, hash); if (!h) { h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto, skb, dataoff, hash); 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_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("normal packet for %p\n", ct); *ctinfo = IP_CT_ESTABLISHED; } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { pr_debug("related packet for %p\n", ct); *ctinfo = IP_CT_RELATED; } else { pr_debug("new packet for %p\n", ct); *ctinfo = IP_CT_NEW; } *set_reply = 0; } nf_ct_set(skb, ct, *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, *tmpl; enum ip_conntrack_info ctinfo; struct nf_conntrack_l3proto *l3proto; struct nf_conntrack_l4proto *l4proto; unsigned int *timeouts; unsigned int dataoff; u_int8_t protonum; int set_reply = 0; int ret; tmpl = nf_ct_get(skb, &ctinfo); if (tmpl) { /* Previously seen (loopback or untracked)? Ignore. */ if (!nf_ct_is_template(tmpl)) { NF_CT_STAT_INC_ATOMIC(net, ignore); return NF_ACCEPT; } skb->_nfct = 0; } /* rcu_read_lock()ed by nf_hook_thresh */ 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 occurred\n"); NF_CT_STAT_INC_ATOMIC(net, error); NF_CT_STAT_INC_ATOMIC(net, invalid); ret = -ret; goto out; } 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, tmpl, skb, dataoff, pf, hooknum); if (ret <= 0) { NF_CT_STAT_INC_ATOMIC(net, error); NF_CT_STAT_INC_ATOMIC(net, invalid); ret = -ret; goto out; } /* ICMP[v6] protocol trackers may assign one conntrack. */ if (skb->_nfct) goto out; } repeat: ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum, l3proto, l4proto, &set_reply, &ctinfo); if (!ct) { /* Not valid part of a connection */ NF_CT_STAT_INC_ATOMIC(net, invalid); ret = NF_ACCEPT; goto out; } if (IS_ERR(ct)) { /* Too stressed to deal. */ NF_CT_STAT_INC_ATOMIC(net, drop); ret = NF_DROP; goto out; } NF_CT_ASSERT(skb_nfct(skb)); /* Decide what timeout policy we want to apply to this flow. */ timeouts = nf_ct_timeout_lookup(net, ct, l4proto); ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts); 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(&ct->ct_general); skb->_nfct = 0; NF_CT_STAT_INC_ATOMIC(net, invalid); if (ret == -NF_DROP) NF_CT_STAT_INC_ATOMIC(net, drop); /* Special case: TCP tracker reports an attempt to reopen a * closed/aborted connection. We have to go back and create a * fresh conntrack. */ if (ret == -NF_REPEAT) goto repeat; ret = -ret; goto out; } if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) nf_conntrack_event_cache(IPCT_REPLY, ct); out: if (tmpl) nf_ct_put(tmpl); 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); /* 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(); __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 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) { NF_CT_ASSERT(skb); /* 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)) extra_jiffies += nfct_time_stamp; ct->timeout = extra_jiffies; acct: if (do_acct) nf_ct_acct_update(ct, ctinfo, skb->len); } 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) { nf_ct_acct_update(ct, ctinfo, skb->len); return nf_ct_delete(ct, 0, 0); } EXPORT_SYMBOL_GPL(nf_ct_kill_acct); #if IS_ENABLED(CONFIG_NF_CT_NETLINK) #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) { if (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)) goto nla_put_failure; 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); int nf_ct_port_nlattr_tuple_size(void) { return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); } EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); #endif /* Used by ipt_REJECT and ip6t_REJECT. */ static void nf_conntrack_attach(struct sk_buff *nskb, const 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_REPLY; else ctinfo = IP_CT_RELATED; /* Attach to new skbuff, and increment count */ nf_ct_set(nskb, ct, ctinfo); nf_conntrack_get(skb_nfct(nskb)); } /* 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_nulls_node *n; int cpu; spinlock_t *lockp; for (; *bucket < nf_conntrack_htable_size; (*bucket)++) { lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS]; local_bh_disable(); nf_conntrack_lock(lockp); if (*bucket < nf_conntrack_htable_size) { hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnnode) { if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL) continue; ct = nf_ct_tuplehash_to_ctrack(h); if (net_eq(nf_ct_net(ct), net) && iter(ct, data)) goto found; } } spin_unlock(lockp); local_bh_enable(); cond_resched(); } for_each_possible_cpu(cpu) { struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu); spin_lock_bh(&pcpu->lock); hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) { ct = nf_ct_tuplehash_to_ctrack(h); if (iter(ct, data)) set_bit(IPS_DYING_BIT, &ct->status); } spin_unlock_bh(&pcpu->lock); cond_resched(); } return NULL; found: atomic_inc(&ct->ct_general.use); spin_unlock(lockp); local_bh_enable(); return ct; } void nf_ct_iterate_cleanup(struct net *net, int (*iter)(struct nf_conn *i, void *data), void *data, u32 portid, int report) { struct nf_conn *ct; unsigned int bucket = 0; might_sleep(); if (atomic_read(&net->ct.count) == 0) return; while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) { /* Time to push up daises... */ nf_ct_delete(ct, portid, report); nf_ct_put(ct); cond_resched(); } } EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup); static int kill_all(struct nf_conn *i, void *data) { return 1; } void nf_ct_free_hashtable(void *hash, unsigned int size) { if (is_vmalloc_addr(hash)) vfree(hash); else free_pages((unsigned long)hash, get_order(sizeof(struct hlist_head) * size)); } EXPORT_SYMBOL_GPL(nf_ct_free_hashtable); static int untrack_refs(void) { int cnt = 0, cpu; for_each_possible_cpu(cpu) { struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); cnt += atomic_read(&ct->ct_general.use) - 1; } return cnt; } void nf_conntrack_cleanup_start(void) { conntrack_gc_work.exiting = true; RCU_INIT_POINTER(ip_ct_attach, NULL); } void nf_conntrack_cleanup_end(void) { RCU_INIT_POINTER(nf_ct_destroy, NULL); while (untrack_refs() > 0) schedule(); cancel_delayed_work_sync(&conntrack_gc_work.dwork); nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_htable_size); nf_conntrack_proto_fini(); nf_conntrack_seqadj_fini(); nf_conntrack_labels_fini(); nf_conntrack_helper_fini(); nf_conntrack_timeout_fini(); nf_conntrack_ecache_fini(); nf_conntrack_tstamp_fini(); nf_conntrack_acct_fini(); nf_conntrack_expect_fini(); kmem_cache_destroy(nf_conntrack_cachep); } /* * Mishearing the voices in his head, our hero wonders how he's * supposed to kill the mall. */ void nf_conntrack_cleanup_net(struct net *net) { LIST_HEAD(single); list_add(&net->exit_list, &single); nf_conntrack_cleanup_net_list(&single); } void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list) { int busy; struct net *net; /* * This makes sure all current packets have passed through * netfilter framework. Roll on, two-stage module * delete... */ synchronize_net(); i_see_dead_people: busy = 0; list_for_each_entry(net, net_exit_list, exit_list) { nf_ct_iterate_cleanup(net, kill_all, NULL, 0, 0); if (atomic_read(&net->ct.count) != 0) busy = 1; } if (busy) { schedule(); goto i_see_dead_people; } list_for_each_entry(net, net_exit_list, exit_list) { nf_conntrack_proto_pernet_fini(net); nf_conntrack_helper_pernet_fini(net); nf_conntrack_ecache_pernet_fini(net); nf_conntrack_tstamp_pernet_fini(net); nf_conntrack_acct_pernet_fini(net); nf_conntrack_expect_pernet_fini(net); free_percpu(net->ct.stat); free_percpu(net->ct.pcpu_lists); } } void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls) { struct hlist_nulls_head *hash; unsigned int nr_slots, i; size_t sz; if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head))) return NULL; BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); if (nr_slots > (UINT_MAX / sizeof(struct hlist_nulls_head))) return NULL; sz = nr_slots * sizeof(struct hlist_nulls_head); hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, get_order(sz)); if (!hash) hash = vzalloc(sz); if (hash && nulls) for (i = 0; i < nr_slots; i++) INIT_HLIST_NULLS_HEAD(&hash[i], i); return hash; } EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); int nf_conntrack_hash_resize(unsigned int hashsize) { int i, bucket; unsigned int old_size; struct hlist_nulls_head *hash, *old_hash; struct nf_conntrack_tuple_hash *h; struct nf_conn *ct; if (!hashsize) return -EINVAL; hash = nf_ct_alloc_hashtable(&hashsize, 1); if (!hash) return -ENOMEM; old_size = nf_conntrack_htable_size; if (old_size == hashsize) { nf_ct_free_hashtable(hash, hashsize); return 0; } local_bh_disable(); nf_conntrack_all_lock(); write_seqcount_begin(&nf_conntrack_generation); /* 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 locks. */ for (i = 0; i < nf_conntrack_htable_size; i++) { while (!hlist_nulls_empty(&nf_conntrack_hash[i])) { h = hlist_nulls_entry(nf_conntrack_hash[i].first, struct nf_conntrack_tuple_hash, hnnode); ct = nf_ct_tuplehash_to_ctrack(h); hlist_nulls_del_rcu(&h->hnnode); bucket = __hash_conntrack(nf_ct_net(ct), &h->tuple, hashsize); hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); } } old_size = nf_conntrack_htable_size; old_hash = nf_conntrack_hash; nf_conntrack_hash = hash; nf_conntrack_htable_size = hashsize; write_seqcount_end(&nf_conntrack_generation); nf_conntrack_all_unlock(); local_bh_enable(); synchronize_net(); nf_ct_free_hashtable(old_hash, old_size); return 0; } int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) { unsigned int hashsize; int rc; if (current->nsproxy->net_ns != &init_net) return -EOPNOTSUPP; /* On boot, we can set this without any fancy locking. */ if (!nf_conntrack_htable_size) return param_set_uint(val, kp); rc = kstrtouint(val, 0, &hashsize); if (rc) return rc; return nf_conntrack_hash_resize(hashsize); } EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, &nf_conntrack_htable_size, 0600); void nf_ct_untracked_status_or(unsigned long bits) { int cpu; for_each_possible_cpu(cpu) per_cpu(nf_conntrack_untracked, cpu).status |= bits; } EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or); int nf_conntrack_init_start(void) { int max_factor = 8; int ret = -ENOMEM; int i, cpu; seqcount_init(&nf_conntrack_generation); for (i = 0; i < CONNTRACK_LOCKS; i++) spin_lock_init(&nf_conntrack_locks[i]); if (!nf_conntrack_htable_size) { /* Idea from tcp.c: use 1/16384 of memory. * On i386: 32MB machine has 512 buckets. * >= 1GB machines have 16384 buckets. * >= 4GB machines have 65536 buckets. */ nf_conntrack_htable_size = (((totalram_pages << PAGE_SHIFT) / 16384) / sizeof(struct hlist_head)); if (totalram_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE))) nf_conntrack_htable_size = 65536; else if (totalram_pages > (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, 1); if (!nf_conntrack_hash) return -ENOMEM; nf_conntrack_max = max_factor * nf_conntrack_htable_size; nf_conntrack_cachep = kmem_cache_create("nf_conntrack", sizeof(struct nf_conn), NFCT_INFOMASK + 1, SLAB_DESTROY_BY_RCU | SLAB_HWCACHE_ALIGN, NULL); if (!nf_conntrack_cachep) goto err_cachep; printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n", NF_CONNTRACK_VERSION, nf_conntrack_htable_size, nf_conntrack_max); ret = nf_conntrack_expect_init(); if (ret < 0) goto err_expect; ret = nf_conntrack_acct_init(); if (ret < 0) goto err_acct; ret = nf_conntrack_tstamp_init(); if (ret < 0) goto err_tstamp; ret = nf_conntrack_ecache_init(); if (ret < 0) goto err_ecache; ret = nf_conntrack_timeout_init(); if (ret < 0) goto err_timeout; ret = nf_conntrack_helper_init(); if (ret < 0) goto err_helper; ret = nf_conntrack_labels_init(); if (ret < 0) goto err_labels; ret = nf_conntrack_seqadj_init(); if (ret < 0) goto err_seqadj; ret = nf_conntrack_proto_init(); if (ret < 0) goto err_proto; /* Set up fake conntrack: to never be deleted, not in any hashes */ for_each_possible_cpu(cpu) { struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); write_pnet(&ct->ct_net, &init_net); atomic_set(&ct->ct_general.use, 1); } /* - and look it like as a confirmed connection */ nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED); conntrack_gc_work_init(&conntrack_gc_work); queue_delayed_work(system_long_wq, &conntrack_gc_work.dwork, HZ); return 0; err_proto: nf_conntrack_seqadj_fini(); err_seqadj: nf_conntrack_labels_fini(); err_labels: nf_conntrack_helper_fini(); err_helper: nf_conntrack_timeout_fini(); err_timeout: nf_conntrack_ecache_fini(); err_ecache: nf_conntrack_tstamp_fini(); err_tstamp: nf_conntrack_acct_fini(); err_acct: nf_conntrack_expect_fini(); err_expect: kmem_cache_destroy(nf_conntrack_cachep); err_cachep: nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_htable_size); return ret; } void nf_conntrack_init_end(void) { /* For use by REJECT target */ RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach); RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack); } /* * We need to use special "null" values, not used in hash table */ #define UNCONFIRMED_NULLS_VAL ((1<<30)+0) #define DYING_NULLS_VAL ((1<<30)+1) #define TEMPLATE_NULLS_VAL ((1<<30)+2) int nf_conntrack_init_net(struct net *net) { int ret = -ENOMEM; int cpu; atomic_set(&net->ct.count, 0); net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu); if (!net->ct.pcpu_lists) goto err_stat; for_each_possible_cpu(cpu) { struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu); spin_lock_init(&pcpu->lock); INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL); INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL); } net->ct.stat = alloc_percpu(struct ip_conntrack_stat); if (!net->ct.stat) goto err_pcpu_lists; ret = nf_conntrack_expect_pernet_init(net); if (ret < 0) goto err_expect; ret = nf_conntrack_acct_pernet_init(net); if (ret < 0) goto err_acct; ret = nf_conntrack_tstamp_pernet_init(net); if (ret < 0) goto err_tstamp; ret = nf_conntrack_ecache_pernet_init(net); if (ret < 0) goto err_ecache; ret = nf_conntrack_helper_pernet_init(net); if (ret < 0) goto err_helper; ret = nf_conntrack_proto_pernet_init(net); if (ret < 0) goto err_proto; return 0; err_proto: nf_conntrack_helper_pernet_fini(net); err_helper: nf_conntrack_ecache_pernet_fini(net); err_ecache: nf_conntrack_tstamp_pernet_fini(net); err_tstamp: nf_conntrack_acct_pernet_fini(net); err_acct: nf_conntrack_expect_pernet_fini(net); err_expect: free_percpu(net->ct.stat); err_pcpu_lists: free_percpu(net->ct.pcpu_lists); err_stat: return ret; }