// SPDX-License-Identifier: GPL-2.0-only /* 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 */ #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 "nf_internals.h" __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 next_bucket; u32 avg_timeout; u32 count; u32 start_time; bool exiting; bool early_drop; }; static __read_mostly struct kmem_cache *nf_conntrack_cachep; static DEFINE_SPINLOCK(nf_conntrack_locks_all_lock); static __read_mostly bool nf_conntrack_locks_all; /* serialize hash resizes and nf_ct_iterate_cleanup */ static DEFINE_MUTEX(nf_conntrack_mutex); #define GC_SCAN_INTERVAL_MAX (60ul * HZ) #define GC_SCAN_INTERVAL_MIN (1ul * HZ) /* clamp timeouts to this value (TCP unacked) */ #define GC_SCAN_INTERVAL_CLAMP (300ul * HZ) /* Initial bias pretending we have 100 entries at the upper bound so we don't * wakeup often just because we have three entries with a 1s timeout while still * allowing non-idle machines to wakeup more often when needed. */ #define GC_SCAN_INITIAL_COUNT 100 #define GC_SCAN_INTERVAL_INIT GC_SCAN_INTERVAL_MAX #define GC_SCAN_MAX_DURATION msecs_to_jiffies(10) #define GC_SCAN_EXPIRED_MAX (64000u / HZ) #define MIN_CHAINLEN 50u #define MAX_CHAINLEN (80u - MIN_CHAINLEN) static struct conntrack_gc_work conntrack_gc_work; void nf_conntrack_lock(spinlock_t *lock) __acquires(lock) { /* 1) Acquire the lock */ spin_lock(lock); /* 2) read nf_conntrack_locks_all, with ACQUIRE semantics * It pairs with the smp_store_release() in nf_conntrack_all_unlock() */ if (likely(smp_load_acquire(&nf_conntrack_locks_all) == false)) return; /* fast path failed, unlock */ spin_unlock(lock); /* Slow path 1) get global lock */ spin_lock(&nf_conntrack_locks_all_lock); /* Slow path 2) get the lock we want */ spin_lock(lock); /* Slow path 3) release the global lock */ spin_unlock(&nf_conntrack_locks_all_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) __acquires(&nf_conntrack_locks_all_lock) { int i; spin_lock(&nf_conntrack_locks_all_lock); /* For nf_contrack_locks_all, only the latest time when another * CPU will see an update is controlled, by the "release" of the * spin_lock below. * The earliest time is not controlled, an thus KCSAN could detect * a race when nf_conntract_lock() reads the variable. * WRITE_ONCE() is used to ensure the compiler will not * optimize the write. */ WRITE_ONCE(nf_conntrack_locks_all, true); for (i = 0; i < CONNTRACK_LOCKS; i++) { spin_lock(&nf_conntrack_locks[i]); /* This spin_unlock provides the "release" to ensure that * nf_conntrack_locks_all==true is visible to everyone that * acquired spin_lock(&nf_conntrack_locks[]). */ spin_unlock(&nf_conntrack_locks[i]); } } static void nf_conntrack_all_unlock(void) __releases(&nf_conntrack_locks_all_lock) { /* 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. * It pairs with the smp_load_acquire() in nf_conntrack_lock() */ 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; EXPORT_SYMBOL_GPL(nf_conntrack_max); seqcount_spinlock_t nf_conntrack_generation __read_mostly; static siphash_aligned_key_t nf_conntrack_hash_rnd; static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, unsigned int zoneid, const struct net *net) { siphash_key_t key; get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd)); key = nf_conntrack_hash_rnd; key.key[0] ^= zoneid; key.key[1] ^= net_hash_mix(net); return siphash((void *)tuple, offsetofend(struct nf_conntrack_tuple, dst.__nfct_hash_offsetend), &key); } 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 zoneid, unsigned int size) { return reciprocal_scale(hash_conntrack_raw(tuple, zoneid, net), size); } static u32 hash_conntrack(const struct net *net, const struct nf_conntrack_tuple *tuple, unsigned int zoneid) { return scale_hash(hash_conntrack_raw(tuple, zoneid, net)); } static bool nf_ct_get_tuple_ports(const struct sk_buff *skb, unsigned int dataoff, struct nf_conntrack_tuple *tuple) { struct { __be16 sport; __be16 dport; } _inet_hdr, *inet_hdr; /* Actually only need first 4 bytes to get ports. */ inet_hdr = skb_header_pointer(skb, dataoff, sizeof(_inet_hdr), &_inet_hdr); if (!inet_hdr) return false; tuple->src.u.udp.port = inet_hdr->sport; tuple->dst.u.udp.port = inet_hdr->dport; return true; } static 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) { unsigned int size; const __be32 *ap; __be32 _addrs[8]; memset(tuple, 0, sizeof(*tuple)); tuple->src.l3num = l3num; switch (l3num) { case NFPROTO_IPV4: nhoff += offsetof(struct iphdr, saddr); size = 2 * sizeof(__be32); break; case NFPROTO_IPV6: nhoff += offsetof(struct ipv6hdr, saddr); size = sizeof(_addrs); break; default: return true; } ap = skb_header_pointer(skb, nhoff, size, _addrs); if (!ap) return false; switch (l3num) { case NFPROTO_IPV4: tuple->src.u3.ip = ap[0]; tuple->dst.u3.ip = ap[1]; break; case NFPROTO_IPV6: memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6)); memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6)); break; } tuple->dst.protonum = protonum; tuple->dst.dir = IP_CT_DIR_ORIGINAL; switch (protonum) { #if IS_ENABLED(CONFIG_IPV6) case IPPROTO_ICMPV6: return icmpv6_pkt_to_tuple(skb, dataoff, net, tuple); #endif case IPPROTO_ICMP: return icmp_pkt_to_tuple(skb, dataoff, net, tuple); #ifdef CONFIG_NF_CT_PROTO_GRE case IPPROTO_GRE: return gre_pkt_to_tuple(skb, dataoff, net, tuple); #endif case IPPROTO_TCP: case IPPROTO_UDP: #ifdef CONFIG_NF_CT_PROTO_UDPLITE case IPPROTO_UDPLITE: #endif #ifdef CONFIG_NF_CT_PROTO_SCTP case IPPROTO_SCTP: #endif #ifdef CONFIG_NF_CT_PROTO_DCCP case IPPROTO_DCCP: #endif /* fallthrough */ return nf_ct_get_tuple_ports(skb, dataoff, tuple); default: break; } return true; } static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff, u_int8_t *protonum) { int dataoff = -1; const struct iphdr *iph; struct iphdr _iph; iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); if (!iph) return -1; /* Conntrack defragments packets, we might still see fragments * inside ICMP packets though. */ if (iph->frag_off & htons(IP_OFFSET)) return -1; dataoff = nhoff + (iph->ihl << 2); *protonum = iph->protocol; /* Check bogus IP headers */ if (dataoff > skb->len) { pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n", nhoff, iph->ihl << 2, skb->len); return -1; } return dataoff; } #if IS_ENABLED(CONFIG_IPV6) static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff, u8 *protonum) { int protoff = -1; unsigned int extoff = nhoff + sizeof(struct ipv6hdr); __be16 frag_off; u8 nexthdr; if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr), &nexthdr, sizeof(nexthdr)) != 0) { pr_debug("can't get nexthdr\n"); return -1; } protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off); /* * (protoff == skb->len) means the packet has not data, just * IPv6 and possibly extensions headers, but it is tracked anyway */ if (protoff < 0 || (frag_off & htons(~0x7)) != 0) { pr_debug("can't find proto in pkt\n"); return -1; } *protonum = nexthdr; return protoff; } #endif static int get_l4proto(const struct sk_buff *skb, unsigned int nhoff, u8 pf, u8 *l4num) { switch (pf) { case NFPROTO_IPV4: return ipv4_get_l4proto(skb, nhoff, l4num); #if IS_ENABLED(CONFIG_IPV6) case NFPROTO_IPV6: return ipv6_get_l4proto(skb, nhoff, l4num); #endif default: *l4num = 0; break; } return -1; } 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) { u8 protonum; int protoff; protoff = get_l4proto(skb, nhoff, l3num, &protonum); if (protoff <= 0) return false; return nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple); } EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); bool nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, const struct nf_conntrack_tuple *orig) { memset(inverse, 0, sizeof(*inverse)); inverse->src.l3num = orig->src.l3num; switch (orig->src.l3num) { case NFPROTO_IPV4: inverse->src.u3.ip = orig->dst.u3.ip; inverse->dst.u3.ip = orig->src.u3.ip; break; case NFPROTO_IPV6: inverse->src.u3.in6 = orig->dst.u3.in6; inverse->dst.u3.in6 = orig->src.u3.in6; break; default: break; } inverse->dst.dir = !orig->dst.dir; inverse->dst.protonum = orig->dst.protonum; switch (orig->dst.protonum) { case IPPROTO_ICMP: return nf_conntrack_invert_icmp_tuple(inverse, orig); #if IS_ENABLED(CONFIG_IPV6) case IPPROTO_ICMPV6: return nf_conntrack_invert_icmpv6_tuple(inverse, orig); #endif } inverse->src.u.all = orig->dst.u.all; inverse->dst.u.all = orig->src.u.all; return true; } EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); /* Generate a almost-unique pseudo-id for a given conntrack. * * intentionally doesn't re-use any of the seeds used for hash * table location, we assume id gets exposed to userspace. * * Following nf_conn items do not change throughout lifetime * of the nf_conn: * * 1. nf_conn address * 2. nf_conn->master address (normally NULL) * 3. the associated net namespace * 4. the original direction tuple */ u32 nf_ct_get_id(const struct nf_conn *ct) { static siphash_aligned_key_t ct_id_seed; unsigned long a, b, c, d; net_get_random_once(&ct_id_seed, sizeof(ct_id_seed)); a = (unsigned long)ct; b = (unsigned long)ct->master; c = (unsigned long)nf_ct_net(ct); d = (unsigned long)siphash(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, sizeof(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple), &ct_id_seed); #ifdef CONFIG_64BIT return siphash_4u64((u64)a, (u64)b, (u64)c, (u64)d, &ct_id_seed); #else return siphash_4u32((u32)a, (u32)b, (u32)c, (u32)d, &ct_id_seed); #endif } EXPORT_SYMBOL_GPL(nf_ct_get_id); static void clean_from_lists(struct nf_conn *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); } #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK) /* Released via nf_ct_destroy() */ 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); refcount_set(&tmpl->ct_general.use, 1); return tmpl; } EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc); void nf_ct_tmpl_free(struct nf_conn *tmpl) { kfree(tmpl->ext); 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_gre_conntrack(struct nf_conn *ct) { #ifdef CONFIG_NF_CT_PROTO_GRE struct nf_conn *master = ct->master; if (master) nf_ct_gre_keymap_destroy(master); #endif } void nf_ct_destroy(struct nf_conntrack *nfct) { struct nf_conn *ct = (struct nf_conn *)nfct; WARN_ON(refcount_read(&nfct->use) != 0); if (unlikely(nf_ct_is_template(ct))) { nf_ct_tmpl_free(ct); return; } if (unlikely(nf_ct_protonum(ct) == IPPROTO_GRE)) destroy_gre_conntrack(ct); /* 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); if (ct->master) nf_ct_put(ct->master); nf_conntrack_free(ct); } EXPORT_SYMBOL(nf_ct_destroy); 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; do { sequence = read_seqcount_begin(&nf_conntrack_generation); hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL)); reply_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY)); } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); clean_from_lists(ct); nf_conntrack_double_unlock(hash, reply_hash); } static void nf_ct_delete_from_lists(struct nf_conn *ct) { nf_ct_helper_destroy(ct); local_bh_disable(); __nf_ct_delete_from_lists(ct); local_bh_enable(); } static void nf_ct_add_to_ecache_list(struct nf_conn *ct) { #ifdef CONFIG_NF_CONNTRACK_EVENTS struct nf_conntrack_net *cnet = nf_ct_pernet(nf_ct_net(ct)); spin_lock(&cnet->ecache.dying_lock); hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, &cnet->ecache.dying_list); spin_unlock(&cnet->ecache.dying_lock); #endif } bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report) { struct nf_conn_tstamp *tstamp; struct net *net; if (test_and_set_bit(IPS_DYING_BIT, &ct->status)) return false; tstamp = nf_conn_tstamp_find(ct); if (tstamp) { s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp; tstamp->stop = ktime_get_real_ns(); if (timeout < 0) tstamp->stop -= jiffies_to_nsecs(-timeout); } 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_helper_destroy(ct); local_bh_disable(); __nf_ct_delete_from_lists(ct); nf_ct_add_to_ecache_list(ct); local_bh_enable(); nf_conntrack_ecache_work(nf_ct_net(ct), NFCT_ECACHE_DESTROY_FAIL); return false; } net = nf_ct_net(ct); if (nf_conntrack_ecache_dwork_pending(net)) nf_conntrack_ecache_work(net, NFCT_ECACHE_DESTROY_SENT); 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)); } static inline bool nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2) { return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple, &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) && nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple, &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) && nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) && nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) && net_eq(nf_ct_net(ct1), nf_ct_net(ct2)); } /* caller must hold rcu readlock and none of the nf_conntrack_locks */ static void nf_ct_gc_expired(struct nf_conn *ct) { if (!refcount_inc_not_zero(&ct->ct_general.use)) return; /* load ->status after refcount increase */ smp_acquire__after_ctrl_dep(); 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_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; h = ____nf_conntrack_find(net, zone, tuple, hash); if (h) { /* We have a candidate that matches the tuple we're interested * in, try to obtain a reference and re-check tuple */ ct = nf_ct_tuplehash_to_ctrack(h); if (likely(refcount_inc_not_zero(&ct->ct_general.use))) { /* re-check key after refcount */ smp_acquire__after_ctrl_dep(); if (likely(nf_ct_key_equal(h, tuple, zone, net))) return h; /* TYPESAFE_BY_RCU recycled the candidate */ nf_ct_put(ct); } h = NULL; } 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) { unsigned int rid, zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL); struct nf_conntrack_tuple_hash *thash; rcu_read_lock(); thash = __nf_conntrack_find_get(net, zone, tuple, hash_conntrack_raw(tuple, zone_id, net)); if (thash) goto out_unlock; rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY); if (rid != zone_id) thash = __nf_conntrack_find_get(net, zone, tuple, hash_conntrack_raw(tuple, rid, net)); out_unlock: rcu_read_unlock(); return thash; } 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]); } static bool nf_ct_ext_valid_pre(const struct nf_ct_ext *ext) { /* if ext->gen_id is not equal to nf_conntrack_ext_genid, some extensions * may contain stale pointers to e.g. helper that has been removed. * * The helper can't clear this because the nf_conn object isn't in * any hash and synchronize_rcu() isn't enough because associated skb * might sit in a queue. */ return !ext || ext->gen_id == atomic_read(&nf_conntrack_ext_genid); } static bool nf_ct_ext_valid_post(struct nf_ct_ext *ext) { if (!ext) return true; if (ext->gen_id != atomic_read(&nf_conntrack_ext_genid)) return false; /* inserted into conntrack table, nf_ct_iterate_cleanup() * will find it. Disable nf_ct_ext_find() id check. */ WRITE_ONCE(ext->gen_id, 0); return true; } 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 max_chainlen; unsigned int chainlen = 0; unsigned int sequence; int err = -EEXIST; zone = nf_ct_zone(ct); if (!nf_ct_ext_valid_pre(ct->ext)) return -EAGAIN; local_bh_disable(); do { sequence = read_seqcount_begin(&nf_conntrack_generation); hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL)); reply_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY)); } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); max_chainlen = MIN_CHAINLEN + get_random_u32_below(MAX_CHAINLEN); /* 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; if (chainlen++ > max_chainlen) goto chaintoolong; } chainlen = 0; 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; if (chainlen++ > max_chainlen) goto chaintoolong; } /* If genid has changed, we can't insert anymore because ct * extensions could have stale pointers and nf_ct_iterate_destroy * might have completed its table scan already. * * Increment of the ext genid right after this check is fine: * nf_ct_iterate_destroy blocks until locks are released. */ if (!nf_ct_ext_valid_post(ct->ext)) { err = -EAGAIN; goto out; } smp_wmb(); /* The caller holds a reference to this object */ refcount_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; chaintoolong: NF_CT_STAT_INC(net, chaintoolong); err = -ENOSPC; out: nf_conntrack_double_unlock(hash, reply_hash); local_bh_enable(); return err; } EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert); void nf_ct_acct_add(struct nf_conn *ct, u32 dir, unsigned int packets, unsigned int bytes) { struct nf_conn_acct *acct; acct = nf_conn_acct_find(ct); if (acct) { struct nf_conn_counter *counter = acct->counter; atomic64_add(packets, &counter[dir].packets); atomic64_add(bytes, &counter[dir].bytes); } } EXPORT_SYMBOL_GPL(nf_ct_acct_add); 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, CTINFO2DIR(ctinfo), bytes); } } static void __nf_conntrack_insert_prepare(struct nf_conn *ct) { struct nf_conn_tstamp *tstamp; refcount_inc(&ct->ct_general.use); /* set conntrack timestamp, if enabled. */ tstamp = nf_conn_tstamp_find(ct); if (tstamp) tstamp->start = ktime_get_real_ns(); } /* caller must hold locks to prevent concurrent changes */ static int __nf_ct_resolve_clash(struct sk_buff *skb, 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); enum ip_conntrack_info ctinfo; struct nf_conn *loser_ct; loser_ct = nf_ct_get(skb, &ctinfo); if (nf_ct_is_dying(ct)) return NF_DROP; if (((ct->status & IPS_NAT_DONE_MASK) == 0) || nf_ct_match(ct, loser_ct)) { struct net *net = nf_ct_net(ct); nf_conntrack_get(&ct->ct_general); nf_ct_acct_merge(ct, ctinfo, loser_ct); nf_ct_put(loser_ct); nf_ct_set(skb, ct, ctinfo); NF_CT_STAT_INC(net, clash_resolve); return NF_ACCEPT; } return NF_DROP; } /** * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry * * @skb: skb that causes the collision * @repl_idx: hash slot for reply direction * * Called when origin or reply direction had a clash. * The skb can be handled without packet drop provided the reply direction * is unique or there the existing entry has the identical tuple in both * directions. * * Caller must hold conntrack table locks to prevent concurrent updates. * * Returns NF_DROP if the clash could not be handled. */ static int nf_ct_resolve_clash_harder(struct sk_buff *skb, u32 repl_idx) { struct nf_conn *loser_ct = (struct nf_conn *)skb_nfct(skb); const struct nf_conntrack_zone *zone; struct nf_conntrack_tuple_hash *h; struct hlist_nulls_node *n; struct net *net; zone = nf_ct_zone(loser_ct); net = nf_ct_net(loser_ct); /* Reply direction must never result in a clash, unless both origin * and reply tuples are identical. */ hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[repl_idx], hnnode) { if (nf_ct_key_equal(h, &loser_ct->tuplehash[IP_CT_DIR_REPLY].tuple, zone, net)) return __nf_ct_resolve_clash(skb, h); } /* We want the clashing entry to go away real soon: 1 second timeout. */ WRITE_ONCE(loser_ct->timeout, nfct_time_stamp + HZ); /* IPS_NAT_CLASH removes the entry automatically on the first * reply. Also prevents UDP tracker from moving the entry to * ASSURED state, i.e. the entry can always be evicted under * pressure. */ loser_ct->status |= IPS_FIXED_TIMEOUT | IPS_NAT_CLASH; __nf_conntrack_insert_prepare(loser_ct); /* fake add for ORIGINAL dir: we want lookups to only find the entry * already in the table. This also hides the clashing entry from * ctnetlink iteration, i.e. conntrack -L won't show them. */ hlist_nulls_add_fake(&loser_ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); hlist_nulls_add_head_rcu(&loser_ct->tuplehash[IP_CT_DIR_REPLY].hnnode, &nf_conntrack_hash[repl_idx]); NF_CT_STAT_INC(net, clash_resolve); return NF_ACCEPT; } /** * nf_ct_resolve_clash - attempt to handle clash without packet drop * * @skb: skb that causes the clash * @h: tuplehash of the clashing entry already in table * @reply_hash: hash slot for reply direction * * A conntrack entry can be inserted to the connection tracking table * if there is no existing entry with an identical tuple. * * If there is one, @skb (and the assocated, unconfirmed conntrack) has * to be dropped. In case @skb is retransmitted, next conntrack lookup * will find the already-existing entry. * * The major problem with such packet drop is the extra delay added by * the packet loss -- it will take some time for a retransmit to occur * (or the sender to time out when waiting for a reply). * * This function attempts to handle the situation without packet drop. * * If @skb has no NAT transformation or if the colliding entries are * exactly the same, only the to-be-confirmed conntrack entry is discarded * and @skb is associated with the conntrack entry already in the table. * * Failing that, the new, unconfirmed conntrack is still added to the table * provided that the collision only occurs in the ORIGINAL direction. * The new entry will be added only in the non-clashing REPLY direction, * so packets in the ORIGINAL direction will continue to match the existing * entry. The new entry will also have a fixed timeout so it expires -- * due to the collision, it will only see reply traffic. * * Returns NF_DROP if the clash could not be resolved. */ static __cold noinline int nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h, u32 reply_hash) { /* This is the conntrack entry already in hashes that won race. */ struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); const struct nf_conntrack_l4proto *l4proto; enum ip_conntrack_info ctinfo; struct nf_conn *loser_ct; struct net *net; int ret; loser_ct = nf_ct_get(skb, &ctinfo); net = nf_ct_net(loser_ct); l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct)); if (!l4proto->allow_clash) goto drop; ret = __nf_ct_resolve_clash(skb, h); if (ret == NF_ACCEPT) return ret; ret = nf_ct_resolve_clash_harder(skb, reply_hash); if (ret == NF_ACCEPT) return ret; drop: NF_CT_STAT_INC(net, drop); NF_CT_STAT_INC(net, insert_failed); return NF_DROP; } /* Confirm a connection given skb; places it in hash table */ int __nf_conntrack_confirm(struct sk_buff *skb) { unsigned int chainlen = 0, sequence, max_chainlen; 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 hlist_nulls_node *n; enum ip_conntrack_info ctinfo; struct net *net; 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, nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY)); } 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. */ /* Another skb with the same unconfirmed conntrack may * win the race. This may happen for bridge(br_flood) * or broadcast/multicast packets do skb_clone with * unconfirmed conntrack. */ if (unlikely(nf_ct_is_confirmed(ct))) { WARN_ON_ONCE(1); nf_conntrack_double_unlock(hash, reply_hash); local_bh_enable(); return NF_DROP; } if (!nf_ct_ext_valid_pre(ct->ext)) { NF_CT_STAT_INC(net, insert_failed); goto dying; } /* 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. */ ct->status |= IPS_CONFIRMED; if (unlikely(nf_ct_is_dying(ct))) { NF_CT_STAT_INC(net, insert_failed); goto dying; } max_chainlen = MIN_CHAINLEN + get_random_u32_below(MAX_CHAINLEN); /* 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; if (chainlen++ > max_chainlen) goto chaintoolong; } chainlen = 0; 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; if (chainlen++ > max_chainlen) { chaintoolong: NF_CT_STAT_INC(net, chaintoolong); NF_CT_STAT_INC(net, insert_failed); ret = NF_DROP; goto dying; } } /* Timer relative to confirmation time, not original setting time, otherwise we'd get timer wrap in weird delay cases. */ ct->timeout += nfct_time_stamp; __nf_conntrack_insert_prepare(ct); /* 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(); /* ext area is still valid (rcu read lock is held, * but will go out of scope soon, we need to remove * this conntrack again. */ if (!nf_ct_ext_valid_post(ct->ext)) { nf_ct_kill(ct); NF_CT_STAT_INC_ATOMIC(net, drop); return NF_DROP; } 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: ret = nf_ct_resolve_clash(skb, h, reply_hash); dying: nf_conntrack_double_unlock(hash, reply_hash); local_bh_enable(); return ret; } EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); /* Returns true if a connection corresponds 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, nf_ct_zone_id(zone, IP_CT_DIR_REPLY), 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)) { /* Tuple is taken already, so caller will need to find * a new source port to use. * * Only exception: * If the *original tuples* are identical, then both * conntracks refer to the same flow. * This is a rare situation, it can occur e.g. when * more than one UDP packet is sent from same socket * in different threads. * * Let nf_ct_resolve_clash() deal with this later. */ if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple) && nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL)) continue; 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 (!refcount_inc_not_zero(&tmp->ct_general.use)) continue; /* load ->ct_net and ->status after refcount increase */ smp_acquire__after_ctrl_dep(); /* kill only if still in same netns -- might have moved due to * SLAB_TYPESAFE_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, bucket; for (i = 0; i < NF_CT_EVICTION_RANGE; i++) { struct hlist_nulls_head *ct_hash; unsigned int hsize, drops; rcu_read_lock(); nf_conntrack_get_ht(&ct_hash, &hsize); if (!i) bucket = reciprocal_scale(hash, hsize); else bucket = (bucket + 1) % hsize; drops = early_drop_list(net, &ct_hash[bucket]); rcu_read_unlock(); if (drops) { NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops); return true; } } return false; } static bool gc_worker_skip_ct(const struct nf_conn *ct) { return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct); } static bool gc_worker_can_early_drop(const struct nf_conn *ct) { const struct nf_conntrack_l4proto *l4proto; u8 protonum = nf_ct_protonum(ct); if (test_bit(IPS_OFFLOAD_BIT, &ct->status) && protonum != IPPROTO_UDP) return false; if (!test_bit(IPS_ASSURED_BIT, &ct->status)) return true; l4proto = nf_ct_l4proto_find(protonum); if (l4proto->can_early_drop && l4proto->can_early_drop(ct)) return true; return false; } static void gc_worker(struct work_struct *work) { unsigned int i, hashsz, nf_conntrack_max95 = 0; u32 end_time, start_time = nfct_time_stamp; struct conntrack_gc_work *gc_work; unsigned int expired_count = 0; unsigned long next_run; s32 delta_time; long count; gc_work = container_of(work, struct conntrack_gc_work, dwork.work); i = gc_work->next_bucket; if (gc_work->early_drop) nf_conntrack_max95 = nf_conntrack_max / 100u * 95u; if (i == 0) { gc_work->avg_timeout = GC_SCAN_INTERVAL_INIT; gc_work->count = GC_SCAN_INITIAL_COUNT; gc_work->start_time = start_time; } next_run = gc_work->avg_timeout; count = gc_work->count; end_time = start_time + GC_SCAN_MAX_DURATION; do { struct nf_conntrack_tuple_hash *h; struct hlist_nulls_head *ct_hash; struct hlist_nulls_node *n; struct nf_conn *tmp; rcu_read_lock(); nf_conntrack_get_ht(&ct_hash, &hashsz); if (i >= hashsz) { rcu_read_unlock(); break; } hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) { struct nf_conntrack_net *cnet; struct net *net; long expires; tmp = nf_ct_tuplehash_to_ctrack(h); if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) { nf_ct_offload_timeout(tmp); if (!nf_conntrack_max95) continue; } if (expired_count > GC_SCAN_EXPIRED_MAX) { rcu_read_unlock(); gc_work->next_bucket = i; gc_work->avg_timeout = next_run; gc_work->count = count; delta_time = nfct_time_stamp - gc_work->start_time; /* re-sched immediately if total cycle time is exceeded */ next_run = delta_time < (s32)GC_SCAN_INTERVAL_MAX; goto early_exit; } if (nf_ct_is_expired(tmp)) { nf_ct_gc_expired(tmp); expired_count++; continue; } expires = clamp(nf_ct_expires(tmp), GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_CLAMP); expires = (expires - (long)next_run) / ++count; next_run += expires; if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp)) continue; net = nf_ct_net(tmp); cnet = nf_ct_pernet(net); if (atomic_read(&cnet->count) < nf_conntrack_max95) continue; /* need to take reference to avoid possible races */ if (!refcount_inc_not_zero(&tmp->ct_general.use)) continue; /* load ->status after refcount increase */ smp_acquire__after_ctrl_dep(); if (gc_worker_skip_ct(tmp)) { nf_ct_put(tmp); continue; } if (gc_worker_can_early_drop(tmp)) { nf_ct_kill(tmp); expired_count++; } nf_ct_put(tmp); } /* 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(); i++; delta_time = nfct_time_stamp - end_time; if (delta_time > 0 && i < hashsz) { gc_work->avg_timeout = next_run; gc_work->count = count; gc_work->next_bucket = i; next_run = 0; goto early_exit; } } while (i < hashsz); gc_work->next_bucket = 0; next_run = clamp(next_run, GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_MAX); delta_time = max_t(s32, nfct_time_stamp - gc_work->start_time, 1); if (next_run > (unsigned long)delta_time) next_run -= delta_time; else next_run = 1; early_exit: if (gc_work->exiting) return; if (next_run) gc_work->early_drop = false; queue_delayed_work(system_power_efficient_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->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_conntrack_net *cnet = nf_ct_pernet(net); unsigned int ct_count; struct nf_conn *ct; /* We don't want any race condition at early drop stage */ ct_count = atomic_inc_return(&cnet->count); if (nf_conntrack_max && unlikely(ct_count > nf_conntrack_max)) { if (!early_drop(net, hash)) { if (!conntrack_gc_work.early_drop) conntrack_gc_work.early_drop = true; atomic_dec(&cnet->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_TYPESAFE_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_ONCE(ct->timeout, 0); write_pnet(&ct->ct_net, net); memset_after(ct, 0, __nfct_init_offset); 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. */ refcount_set(&ct->ct_general.use, 0); return ct; out: atomic_dec(&cnet->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); struct nf_conntrack_net *cnet; /* A freed object has refcnt == 0, that's * the golden rule for SLAB_TYPESAFE_BY_RCU */ WARN_ON(refcount_read(&ct->ct_general.use) != 0); if (ct->status & IPS_SRC_NAT_DONE) { const struct nf_nat_hook *nat_hook; rcu_read_lock(); nat_hook = rcu_dereference(nf_nat_hook); if (nat_hook) nat_hook->remove_nat_bysrc(ct); rcu_read_unlock(); } kfree(ct->ext); kmem_cache_free(nf_conntrack_cachep, ct); cnet = nf_ct_pernet(net); smp_mb__before_atomic(); atomic_dec(&cnet->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 noinline struct nf_conntrack_tuple_hash * init_conntrack(struct net *net, struct nf_conn *tmpl, const struct nf_conntrack_tuple *tuple, struct sk_buff *skb, unsigned int dataoff, u32 hash) { struct nf_conn *ct; struct nf_conn_help *help; struct nf_conntrack_tuple repl_tuple; #ifdef CONFIG_NF_CONNTRACK_EVENTS struct nf_conntrack_ecache *ecache; #endif struct nf_conntrack_expect *exp = NULL; const struct nf_conntrack_zone *zone; struct nf_conn_timeout *timeout_ext; struct nf_conntrack_zone tmp; struct nf_conntrack_net *cnet; if (!nf_ct_invert_tuple(&repl_tuple, tuple)) 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) 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); #ifdef CONFIG_NF_CONNTRACK_EVENTS ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; if ((ecache || net->ct.sysctl_events) && !nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, ecache ? ecache->expmask : 0, GFP_ATOMIC)) { nf_conntrack_free(ct); return ERR_PTR(-ENOMEM); } #endif cnet = nf_ct_pernet(net); if (cnet->expect_count) { spin_lock_bh(&nf_conntrack_expect_lock); exp = nf_ct_find_expectation(net, zone, tuple, !tmpl || nf_ct_is_confirmed(tmpl)); if (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, GFP_ATOMIC); if (help) rcu_assign_pointer(help->helper, exp->helper); } #ifdef CONFIG_NF_CONNTRACK_MARK ct->mark = READ_ONCE(exp->master->mark); #endif #ifdef CONFIG_NF_CONNTRACK_SECMARK ct->secmark = exp->master->secmark; #endif NF_CT_STAT_INC(net, expect_new); } spin_unlock_bh(&nf_conntrack_expect_lock); } if (!exp && tmpl) __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); /* Other CPU might have obtained a pointer to this object before it was * released. Because refcount is 0, refcount_inc_not_zero() will fail. * * After refcount_set(1) it will succeed; ensure that zeroing of * ct->status and the correct ct->net pointer are visible; else other * core might observe CONFIRMED bit which means the entry is valid and * in the hash table, but its not (anymore). */ smp_wmb(); /* Now it is going to be associated with an sk_buff, set refcount to 1. */ refcount_set(&ct->ct_general.use, 1); if (exp) { if (exp->expectfn) exp->expectfn(ct, exp); nf_ct_expect_put(exp); } return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; } /* On success, returns 0, sets skb->_nfct | ctinfo */ static int resolve_normal_ct(struct nf_conn *tmpl, struct sk_buff *skb, unsigned int dataoff, u_int8_t protonum, const struct nf_hook_state *state) { const struct nf_conntrack_zone *zone; struct nf_conntrack_tuple tuple; struct nf_conntrack_tuple_hash *h; enum ip_conntrack_info ctinfo; struct nf_conntrack_zone tmp; u32 hash, zone_id, rid; struct nf_conn *ct; if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, state->pf, protonum, state->net, &tuple)) return 0; /* look for tuple match */ zone = nf_ct_zone_tmpl(tmpl, skb, &tmp); zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL); hash = hash_conntrack_raw(&tuple, zone_id, state->net); h = __nf_conntrack_find_get(state->net, zone, &tuple, hash); if (!h) { rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY); if (zone_id != rid) { u32 tmp = hash_conntrack_raw(&tuple, rid, state->net); h = __nf_conntrack_find_get(state->net, zone, &tuple, tmp); } } if (!h) { h = init_conntrack(state->net, tmpl, &tuple, skb, dataoff, hash); if (!h) return 0; if (IS_ERR(h)) return PTR_ERR(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; } else { unsigned long status = READ_ONCE(ct->status); /* Once we've had two way comms, always ESTABLISHED. */ if (likely(status & IPS_SEEN_REPLY)) ctinfo = IP_CT_ESTABLISHED; else if (status & IPS_EXPECTED) ctinfo = IP_CT_RELATED; else ctinfo = IP_CT_NEW; } nf_ct_set(skb, ct, ctinfo); return 0; } /* * icmp packets need special treatment to handle error messages that are * related to a connection. * * Callers need to check if skb has a conntrack assigned when this * helper returns; in such case skb belongs to an already known connection. */ static unsigned int __cold nf_conntrack_handle_icmp(struct nf_conn *tmpl, struct sk_buff *skb, unsigned int dataoff, u8 protonum, const struct nf_hook_state *state) { int ret; if (state->pf == NFPROTO_IPV4 && protonum == IPPROTO_ICMP) ret = nf_conntrack_icmpv4_error(tmpl, skb, dataoff, state); #if IS_ENABLED(CONFIG_IPV6) else if (state->pf == NFPROTO_IPV6 && protonum == IPPROTO_ICMPV6) ret = nf_conntrack_icmpv6_error(tmpl, skb, dataoff, state); #endif else return NF_ACCEPT; if (ret <= 0) NF_CT_STAT_INC_ATOMIC(state->net, error); return ret; } static int generic_packet(struct nf_conn *ct, struct sk_buff *skb, enum ip_conntrack_info ctinfo) { const unsigned int *timeout = nf_ct_timeout_lookup(ct); if (!timeout) timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout; nf_ct_refresh_acct(ct, ctinfo, skb, *timeout); return NF_ACCEPT; } /* Returns verdict for packet, or -1 for invalid. */ static int nf_conntrack_handle_packet(struct nf_conn *ct, struct sk_buff *skb, unsigned int dataoff, enum ip_conntrack_info ctinfo, const struct nf_hook_state *state) { switch (nf_ct_protonum(ct)) { case IPPROTO_TCP: return nf_conntrack_tcp_packet(ct, skb, dataoff, ctinfo, state); case IPPROTO_UDP: return nf_conntrack_udp_packet(ct, skb, dataoff, ctinfo, state); case IPPROTO_ICMP: return nf_conntrack_icmp_packet(ct, skb, ctinfo, state); #if IS_ENABLED(CONFIG_IPV6) case IPPROTO_ICMPV6: return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state); #endif #ifdef CONFIG_NF_CT_PROTO_UDPLITE case IPPROTO_UDPLITE: return nf_conntrack_udplite_packet(ct, skb, dataoff, ctinfo, state); #endif #ifdef CONFIG_NF_CT_PROTO_SCTP case IPPROTO_SCTP: return nf_conntrack_sctp_packet(ct, skb, dataoff, ctinfo, state); #endif #ifdef CONFIG_NF_CT_PROTO_DCCP case IPPROTO_DCCP: return nf_conntrack_dccp_packet(ct, skb, dataoff, ctinfo, state); #endif #ifdef CONFIG_NF_CT_PROTO_GRE case IPPROTO_GRE: return nf_conntrack_gre_packet(ct, skb, dataoff, ctinfo, state); #endif } return generic_packet(ct, skb, ctinfo); } unsigned int nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state) { enum ip_conntrack_info ctinfo; struct nf_conn *ct, *tmpl; u_int8_t protonum; int dataoff, ret; tmpl = nf_ct_get(skb, &ctinfo); if (tmpl || ctinfo == IP_CT_UNTRACKED) { /* Previously seen (loopback or untracked)? Ignore. */ if ((tmpl && !nf_ct_is_template(tmpl)) || ctinfo == IP_CT_UNTRACKED) return NF_ACCEPT; skb->_nfct = 0; } /* rcu_read_lock()ed by nf_hook_thresh */ dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum); if (dataoff <= 0) { NF_CT_STAT_INC_ATOMIC(state->net, invalid); ret = NF_ACCEPT; goto out; } if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) { ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff, protonum, state); if (ret <= 0) { ret = -ret; goto out; } /* ICMP[v6] protocol trackers may assign one conntrack. */ if (skb->_nfct) goto out; } repeat: ret = resolve_normal_ct(tmpl, skb, dataoff, protonum, state); if (ret < 0) { /* Too stressed to deal. */ NF_CT_STAT_INC_ATOMIC(state->net, drop); ret = NF_DROP; goto out; } ct = nf_ct_get(skb, &ctinfo); if (!ct) { /* Not valid part of a connection */ NF_CT_STAT_INC_ATOMIC(state->net, invalid); ret = NF_ACCEPT; goto out; } ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state); if (ret <= 0) { /* Invalid: inverse of the return code tells * the netfilter core what to do */ nf_ct_put(ct); skb->_nfct = 0; /* 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; NF_CT_STAT_INC_ATOMIC(state->net, invalid); if (ret == -NF_DROP) NF_CT_STAT_INC_ATOMIC(state->net, drop); ret = -ret; goto out; } if (ctinfo == IP_CT_ESTABLISHED_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); /* 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, u32 extra_jiffies, bool do_acct) { /* 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; if (READ_ONCE(ct->timeout) != extra_jiffies) WRITE_ONCE(ct->timeout, extra_jiffies); acct: if (do_acct) nf_ct_acct_update(ct, CTINFO2DIR(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, CTINFO2DIR(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. */ 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, u_int32_t flags) { if (flags & CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT)) { if (!tb[CTA_PROTO_SRC_PORT]) return -EINVAL; t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); } if (flags & CTA_FILTER_FLAG(CTA_PROTO_DST_PORT)) { if (!tb[CTA_PROTO_DST_PORT]) return -EINVAL; t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); } return 0; } EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); unsigned int nf_ct_port_nlattr_tuple_size(void) { static unsigned int size __read_mostly; if (!size) size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); return size; } 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)); } static int __nf_conntrack_update(struct net *net, struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info ctinfo) { const struct nf_nat_hook *nat_hook; struct nf_conntrack_tuple_hash *h; struct nf_conntrack_tuple tuple; unsigned int status; int dataoff; u16 l3num; u8 l4num; l3num = nf_ct_l3num(ct); dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num); if (dataoff <= 0) return NF_DROP; if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num, l4num, net, &tuple)) return NF_DROP; if (ct->status & IPS_SRC_NAT) { memcpy(tuple.src.u3.all, ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all, sizeof(tuple.src.u3.all)); tuple.src.u.all = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all; } if (ct->status & IPS_DST_NAT) { memcpy(tuple.dst.u3.all, ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all, sizeof(tuple.dst.u3.all)); tuple.dst.u.all = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all; } h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple); if (!h) return NF_ACCEPT; /* Store status bits of the conntrack that is clashing to re-do NAT * mangling according to what it has been done already to this packet. */ status = ct->status; nf_ct_put(ct); ct = nf_ct_tuplehash_to_ctrack(h); nf_ct_set(skb, ct, ctinfo); nat_hook = rcu_dereference(nf_nat_hook); if (!nat_hook) return NF_ACCEPT; if (status & IPS_SRC_NAT) { unsigned int verdict = nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC, IP_CT_DIR_ORIGINAL); if (verdict != NF_ACCEPT) return verdict; } if (status & IPS_DST_NAT) { unsigned int verdict = nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST, IP_CT_DIR_ORIGINAL); if (verdict != NF_ACCEPT) return verdict; } return NF_ACCEPT; } /* This packet is coming from userspace via nf_queue, complete the packet * processing after the helper invocation in nf_confirm(). */ static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info ctinfo) { const struct nf_conntrack_helper *helper; const struct nf_conn_help *help; int protoff; help = nfct_help(ct); if (!help) return NF_ACCEPT; helper = rcu_dereference(help->helper); if (!helper) return NF_ACCEPT; if (!(helper->flags & NF_CT_HELPER_F_USERSPACE)) return NF_ACCEPT; switch (nf_ct_l3num(ct)) { case NFPROTO_IPV4: protoff = skb_network_offset(skb) + ip_hdrlen(skb); break; #if IS_ENABLED(CONFIG_IPV6) case NFPROTO_IPV6: { __be16 frag_off; u8 pnum; pnum = ipv6_hdr(skb)->nexthdr; protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum, &frag_off); if (protoff < 0 || (frag_off & htons(~0x7)) != 0) return NF_ACCEPT; break; } #endif default: return NF_ACCEPT; } if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) && !nf_is_loopback_packet(skb)) { if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) { NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop); return NF_DROP; } } /* We've seen it coming out the other side: confirm it */ return nf_conntrack_confirm(skb); } static int nf_conntrack_update(struct net *net, struct sk_buff *skb) { enum ip_conntrack_info ctinfo; struct nf_conn *ct; ct = nf_ct_get(skb, &ctinfo); if (!ct) return NF_ACCEPT; if (!nf_ct_is_confirmed(ct)) { int ret = __nf_conntrack_update(net, skb, ct, ctinfo); if (ret != NF_ACCEPT) return ret; ct = nf_ct_get(skb, &ctinfo); if (!ct) return NF_ACCEPT; } return nf_confirm_cthelper(skb, ct, ctinfo); } static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, const struct sk_buff *skb) { const struct nf_conntrack_tuple *src_tuple; const struct nf_conntrack_tuple_hash *hash; struct nf_conntrack_tuple srctuple; enum ip_conntrack_info ctinfo; struct nf_conn *ct; ct = nf_ct_get(skb, &ctinfo); if (ct) { src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo)); memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple)); return true; } if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), NFPROTO_IPV4, dev_net(skb->dev), &srctuple)) return false; hash = nf_conntrack_find_get(dev_net(skb->dev), &nf_ct_zone_dflt, &srctuple); if (!hash) return false; ct = nf_ct_tuplehash_to_ctrack(hash); src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir); memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple)); nf_ct_put(ct); return true; } /* Bring out ya dead! */ static struct nf_conn * get_next_corpse(int (*iter)(struct nf_conn *i, void *data), const struct nf_ct_iter_data *iter_data, unsigned int *bucket) { struct nf_conntrack_tuple_hash *h; struct nf_conn *ct; struct hlist_nulls_node *n; spinlock_t *lockp; for (; *bucket < nf_conntrack_htable_size; (*bucket)++) { struct hlist_nulls_head *hslot = &nf_conntrack_hash[*bucket]; if (hlist_nulls_empty(hslot)) continue; lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS]; local_bh_disable(); nf_conntrack_lock(lockp); hlist_nulls_for_each_entry(h, n, hslot, hnnode) { if (NF_CT_DIRECTION(h) != IP_CT_DIR_REPLY) continue; /* All nf_conn objects are added to hash table twice, one * for original direction tuple, once for the reply tuple. * * Exception: In the IPS_NAT_CLASH case, only the reply * tuple is added (the original tuple already existed for * a different object). * * We only need to call the iterator once for each * conntrack, so we just use the 'reply' direction * tuple while iterating. */ ct = nf_ct_tuplehash_to_ctrack(h); if (iter_data->net && !net_eq(iter_data->net, nf_ct_net(ct))) continue; if (iter(ct, iter_data->data)) goto found; } spin_unlock(lockp); local_bh_enable(); cond_resched(); } return NULL; found: refcount_inc(&ct->ct_general.use); spin_unlock(lockp); local_bh_enable(); return ct; } static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), const struct nf_ct_iter_data *iter_data) { unsigned int bucket = 0; struct nf_conn *ct; might_sleep(); mutex_lock(&nf_conntrack_mutex); while ((ct = get_next_corpse(iter, iter_data, &bucket)) != NULL) { /* Time to push up daises... */ nf_ct_delete(ct, iter_data->portid, iter_data->report); nf_ct_put(ct); cond_resched(); } mutex_unlock(&nf_conntrack_mutex); } void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data), const struct nf_ct_iter_data *iter_data) { struct net *net = iter_data->net; struct nf_conntrack_net *cnet = nf_ct_pernet(net); might_sleep(); if (atomic_read(&cnet->count) == 0) return; nf_ct_iterate_cleanup(iter, iter_data); } EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net); /** * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table * @iter: callback to invoke for each conntrack * @data: data to pass to @iter * * Like nf_ct_iterate_cleanup, but first marks conntracks on the * unconfirmed list as dying (so they will not be inserted into * main table). * * Can only be called in module exit path. */ void nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data) { struct nf_ct_iter_data iter_data = {}; struct net *net; down_read(&net_rwsem); for_each_net(net) { struct nf_conntrack_net *cnet = nf_ct_pernet(net); if (atomic_read(&cnet->count) == 0) continue; nf_queue_nf_hook_drop(net); } up_read(&net_rwsem); /* Need to wait for netns cleanup worker to finish, if its * running -- it might have deleted a net namespace from * the global list, so hook drop above might not have * affected all namespaces. */ net_ns_barrier(); /* a skb w. unconfirmed conntrack could have been reinjected just * before we called nf_queue_nf_hook_drop(). * * This makes sure its inserted into conntrack table. */ synchronize_net(); nf_ct_ext_bump_genid(); iter_data.data = data; nf_ct_iterate_cleanup(iter, &iter_data); /* Another cpu might be in a rcu read section with * rcu protected pointer cleared in iter callback * or hidden via nf_ct_ext_bump_genid() above. * * Wait until those are done. */ synchronize_rcu(); } EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy); static int kill_all(struct nf_conn *i, void *data) { return 1; } void nf_conntrack_cleanup_start(void) { cleanup_nf_conntrack_bpf(); conntrack_gc_work.exiting = true; } void nf_conntrack_cleanup_end(void) { RCU_INIT_POINTER(nf_ct_hook, NULL); cancel_delayed_work_sync(&conntrack_gc_work.dwork); kvfree(nf_conntrack_hash); nf_conntrack_proto_fini(); nf_conntrack_helper_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) { struct nf_ct_iter_data iter_data = {}; struct net *net; int busy; /* * This makes sure all current packets have passed through * netfilter framework. Roll on, two-stage module * delete... */ synchronize_rcu_expedited(); i_see_dead_people: busy = 0; list_for_each_entry(net, net_exit_list, exit_list) { struct nf_conntrack_net *cnet = nf_ct_pernet(net); iter_data.net = net; nf_ct_iterate_cleanup_net(kill_all, &iter_data); if (atomic_read(&cnet->count) != 0) busy = 1; } if (busy) { schedule(); goto i_see_dead_people; } list_for_each_entry(net, net_exit_list, exit_list) { nf_conntrack_ecache_pernet_fini(net); nf_conntrack_expect_pernet_fini(net); free_percpu(net->ct.stat); } } void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls) { struct hlist_nulls_head *hash; unsigned int nr_slots, i; 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)); hash = kvcalloc(nr_slots, sizeof(struct hlist_nulls_head), GFP_KERNEL); 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; mutex_lock(&nf_conntrack_mutex); old_size = nf_conntrack_htable_size; if (old_size == hashsize) { mutex_unlock(&nf_conntrack_mutex); kvfree(hash); 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])) { unsigned int zone_id; 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); zone_id = nf_ct_zone_id(nf_ct_zone(ct), NF_CT_DIRECTION(h)); bucket = __hash_conntrack(nf_ct_net(ct), &h->tuple, zone_id, hashsize); hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); } } 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(); mutex_unlock(&nf_conntrack_mutex); synchronize_net(); kvfree(old_hash); return 0; } int nf_conntrack_set_hashsize(const char *val, const 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_hash) return param_set_uint(val, kp); rc = kstrtouint(val, 0, &hashsize); if (rc) return rc; return nf_conntrack_hash_resize(hashsize); } int nf_conntrack_init_start(void) { unsigned long nr_pages = totalram_pages(); int max_factor = 8; int ret = -ENOMEM; int i; seqcount_spinlock_init(&nf_conntrack_generation, &nf_conntrack_locks_all_lock); for (i = 0; i < CONNTRACK_LOCKS; i++) spin_lock_init(&nf_conntrack_locks[i]); if (!nf_conntrack_htable_size) { nf_conntrack_htable_size = (((nr_pages << PAGE_SHIFT) / 16384) / sizeof(struct hlist_head)); if (BITS_PER_LONG >= 64 && nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE))) nf_conntrack_htable_size = 262144; else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) nf_conntrack_htable_size = 65536; if (nf_conntrack_htable_size < 1024) nf_conntrack_htable_size = 1024; /* Use a max. factor of one by default to keep the average * hash chain length at 2 entries. Each entry has to be added * twice (once for original direction, once for reply). * When a table size is given we use the old value of 8 to * avoid implicit reduction of the max entries setting. */ max_factor = 1; } 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_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL); if (!nf_conntrack_cachep) goto err_cachep; ret = nf_conntrack_expect_init(); if (ret < 0) goto err_expect; ret = nf_conntrack_helper_init(); if (ret < 0) goto err_helper; ret = nf_conntrack_proto_init(); if (ret < 0) goto err_proto; conntrack_gc_work_init(&conntrack_gc_work); queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ); ret = register_nf_conntrack_bpf(); if (ret < 0) goto err_kfunc; return 0; err_kfunc: cancel_delayed_work_sync(&conntrack_gc_work.dwork); nf_conntrack_proto_fini(); err_proto: nf_conntrack_helper_fini(); err_helper: nf_conntrack_expect_fini(); err_expect: kmem_cache_destroy(nf_conntrack_cachep); err_cachep: kvfree(nf_conntrack_hash); return ret; } static void nf_conntrack_set_closing(struct nf_conntrack *nfct) { struct nf_conn *ct = nf_ct_to_nf_conn(nfct); switch (nf_ct_protonum(ct)) { case IPPROTO_TCP: nf_conntrack_tcp_set_closing(ct); break; } } static const struct nf_ct_hook nf_conntrack_hook = { .update = nf_conntrack_update, .destroy = nf_ct_destroy, .get_tuple_skb = nf_conntrack_get_tuple_skb, .attach = nf_conntrack_attach, .set_closing = nf_conntrack_set_closing, .confirm = __nf_conntrack_confirm, }; void nf_conntrack_init_end(void) { RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook); } /* * We need to use special "null" values, not used in hash table */ #define UNCONFIRMED_NULLS_VAL ((1<<30)+0) int nf_conntrack_init_net(struct net *net) { struct nf_conntrack_net *cnet = nf_ct_pernet(net); int ret = -ENOMEM; BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER); BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS); atomic_set(&cnet->count, 0); net->ct.stat = alloc_percpu(struct ip_conntrack_stat); if (!net->ct.stat) return ret; ret = nf_conntrack_expect_pernet_init(net); if (ret < 0) goto err_expect; nf_conntrack_acct_pernet_init(net); nf_conntrack_tstamp_pernet_init(net); nf_conntrack_ecache_pernet_init(net); nf_conntrack_proto_pernet_init(net); return 0; err_expect: free_percpu(net->ct.stat); return ret; } /* ctnetlink code shared by both ctnetlink and nf_conntrack_bpf */ int __nf_ct_change_timeout(struct nf_conn *ct, u64 timeout) { if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) return -EPERM; __nf_ct_set_timeout(ct, timeout); if (test_bit(IPS_DYING_BIT, &ct->status)) return -ETIME; return 0; } EXPORT_SYMBOL_GPL(__nf_ct_change_timeout); void __nf_ct_change_status(struct nf_conn *ct, unsigned long on, unsigned long off) { unsigned int bit; /* Ignore these unchangable bits */ on &= ~IPS_UNCHANGEABLE_MASK; off &= ~IPS_UNCHANGEABLE_MASK; for (bit = 0; bit < __IPS_MAX_BIT; bit++) { if (on & (1 << bit)) set_bit(bit, &ct->status); else if (off & (1 << bit)) clear_bit(bit, &ct->status); } } EXPORT_SYMBOL_GPL(__nf_ct_change_status); int nf_ct_change_status_common(struct nf_conn *ct, unsigned int status) { unsigned long d; d = ct->status ^ status; if (d & (IPS_EXPECTED|IPS_CONFIRMED|IPS_DYING)) /* unchangeable */ return -EBUSY; if (d & IPS_SEEN_REPLY && !(status & IPS_SEEN_REPLY)) /* SEEN_REPLY bit can only be set */ return -EBUSY; if (d & IPS_ASSURED && !(status & IPS_ASSURED)) /* ASSURED bit can only be set */ return -EBUSY; __nf_ct_change_status(ct, status, 0); return 0; } EXPORT_SYMBOL_GPL(nf_ct_change_status_common);