diff options
Diffstat (limited to 'net/ipv4/inet_hashtables.c')
| -rw-r--r-- | net/ipv4/inet_hashtables.c | 949 |
1 files changed, 949 insertions, 0 deletions
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c new file mode 100644 index 000000000..ad050f847 --- /dev/null +++ b/net/ipv4/inet_hashtables.c @@ -0,0 +1,949 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * Generic INET transport hashtables + * + * Authors: Lotsa people, from code originally in tcp + */ + +#include <linux/module.h> +#include <linux/random.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/wait.h> +#include <linux/vmalloc.h> +#include <linux/memblock.h> + +#include <net/addrconf.h> +#include <net/inet_connection_sock.h> +#include <net/inet_hashtables.h> +#if IS_ENABLED(CONFIG_IPV6) +#include <net/inet6_hashtables.h> +#endif +#include <net/secure_seq.h> +#include <net/ip.h> +#include <net/tcp.h> +#include <net/sock_reuseport.h> + +static u32 inet_ehashfn(const struct net *net, const __be32 laddr, + const __u16 lport, const __be32 faddr, + const __be16 fport) +{ + static u32 inet_ehash_secret __read_mostly; + + net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret)); + + return __inet_ehashfn(laddr, lport, faddr, fport, + inet_ehash_secret + net_hash_mix(net)); +} + +/* This function handles inet_sock, but also timewait and request sockets + * for IPv4/IPv6. + */ +static u32 sk_ehashfn(const struct sock *sk) +{ +#if IS_ENABLED(CONFIG_IPV6) + if (sk->sk_family == AF_INET6 && + !ipv6_addr_v4mapped(&sk->sk_v6_daddr)) + return inet6_ehashfn(sock_net(sk), + &sk->sk_v6_rcv_saddr, sk->sk_num, + &sk->sk_v6_daddr, sk->sk_dport); +#endif + return inet_ehashfn(sock_net(sk), + sk->sk_rcv_saddr, sk->sk_num, + sk->sk_daddr, sk->sk_dport); +} + +/* + * Allocate and initialize a new local port bind bucket. + * The bindhash mutex for snum's hash chain must be held here. + */ +struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep, + struct net *net, + struct inet_bind_hashbucket *head, + const unsigned short snum, + int l3mdev) +{ + struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC); + + if (tb) { + write_pnet(&tb->ib_net, net); + tb->l3mdev = l3mdev; + tb->port = snum; + tb->fastreuse = 0; + tb->fastreuseport = 0; + INIT_HLIST_HEAD(&tb->owners); + hlist_add_head(&tb->node, &head->chain); + } + return tb; +} + +/* + * Caller must hold hashbucket lock for this tb with local BH disabled + */ +void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb) +{ + if (hlist_empty(&tb->owners)) { + __hlist_del(&tb->node); + kmem_cache_free(cachep, tb); + } +} + +void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, + const unsigned short snum) +{ + inet_sk(sk)->inet_num = snum; + sk_add_bind_node(sk, &tb->owners); + inet_csk(sk)->icsk_bind_hash = tb; +} + +/* + * Get rid of any references to a local port held by the given sock. + */ +static void __inet_put_port(struct sock *sk) +{ + struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; + const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num, + hashinfo->bhash_size); + struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash]; + struct inet_bind_bucket *tb; + + spin_lock(&head->lock); + tb = inet_csk(sk)->icsk_bind_hash; + __sk_del_bind_node(sk); + inet_csk(sk)->icsk_bind_hash = NULL; + inet_sk(sk)->inet_num = 0; + inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb); + spin_unlock(&head->lock); +} + +void inet_put_port(struct sock *sk) +{ + local_bh_disable(); + __inet_put_port(sk); + local_bh_enable(); +} +EXPORT_SYMBOL(inet_put_port); + +int __inet_inherit_port(const struct sock *sk, struct sock *child) +{ + struct inet_hashinfo *table = sk->sk_prot->h.hashinfo; + unsigned short port = inet_sk(child)->inet_num; + const int bhash = inet_bhashfn(sock_net(sk), port, + table->bhash_size); + struct inet_bind_hashbucket *head = &table->bhash[bhash]; + struct inet_bind_bucket *tb; + int l3mdev; + + spin_lock(&head->lock); + tb = inet_csk(sk)->icsk_bind_hash; + if (unlikely(!tb)) { + spin_unlock(&head->lock); + return -ENOENT; + } + if (tb->port != port) { + l3mdev = inet_sk_bound_l3mdev(sk); + + /* NOTE: using tproxy and redirecting skbs to a proxy + * on a different listener port breaks the assumption + * that the listener socket's icsk_bind_hash is the same + * as that of the child socket. We have to look up or + * create a new bind bucket for the child here. */ + inet_bind_bucket_for_each(tb, &head->chain) { + if (net_eq(ib_net(tb), sock_net(sk)) && + tb->l3mdev == l3mdev && tb->port == port) + break; + } + if (!tb) { + tb = inet_bind_bucket_create(table->bind_bucket_cachep, + sock_net(sk), head, port, + l3mdev); + if (!tb) { + spin_unlock(&head->lock); + return -ENOMEM; + } + } + inet_csk_update_fastreuse(tb, child); + } + inet_bind_hash(child, tb, port); + spin_unlock(&head->lock); + + return 0; +} +EXPORT_SYMBOL_GPL(__inet_inherit_port); + +static struct inet_listen_hashbucket * +inet_lhash2_bucket_sk(struct inet_hashinfo *h, struct sock *sk) +{ + u32 hash; + +#if IS_ENABLED(CONFIG_IPV6) + if (sk->sk_family == AF_INET6) + hash = ipv6_portaddr_hash(sock_net(sk), + &sk->sk_v6_rcv_saddr, + inet_sk(sk)->inet_num); + else +#endif + hash = ipv4_portaddr_hash(sock_net(sk), + inet_sk(sk)->inet_rcv_saddr, + inet_sk(sk)->inet_num); + return inet_lhash2_bucket(h, hash); +} + +static void inet_hash2(struct inet_hashinfo *h, struct sock *sk) +{ + struct inet_listen_hashbucket *ilb2; + + if (!h->lhash2) + return; + + ilb2 = inet_lhash2_bucket_sk(h, sk); + + spin_lock(&ilb2->lock); + if (sk->sk_reuseport && sk->sk_family == AF_INET6) + hlist_add_tail_rcu(&inet_csk(sk)->icsk_listen_portaddr_node, + &ilb2->head); + else + hlist_add_head_rcu(&inet_csk(sk)->icsk_listen_portaddr_node, + &ilb2->head); + ilb2->count++; + spin_unlock(&ilb2->lock); +} + +static void inet_unhash2(struct inet_hashinfo *h, struct sock *sk) +{ + struct inet_listen_hashbucket *ilb2; + + if (!h->lhash2 || + WARN_ON_ONCE(hlist_unhashed(&inet_csk(sk)->icsk_listen_portaddr_node))) + return; + + ilb2 = inet_lhash2_bucket_sk(h, sk); + + spin_lock(&ilb2->lock); + hlist_del_init_rcu(&inet_csk(sk)->icsk_listen_portaddr_node); + ilb2->count--; + spin_unlock(&ilb2->lock); +} + +static inline int compute_score(struct sock *sk, struct net *net, + const unsigned short hnum, const __be32 daddr, + const int dif, const int sdif) +{ + int score = -1; + + if (net_eq(sock_net(sk), net) && sk->sk_num == hnum && + !ipv6_only_sock(sk)) { + if (sk->sk_rcv_saddr != daddr) + return -1; + + if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif)) + return -1; + score = sk->sk_bound_dev_if ? 2 : 1; + + if (sk->sk_family == PF_INET) + score++; + if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id()) + score++; + } + return score; +} + +static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk, + struct sk_buff *skb, int doff, + __be32 saddr, __be16 sport, + __be32 daddr, unsigned short hnum) +{ + struct sock *reuse_sk = NULL; + u32 phash; + + if (sk->sk_reuseport) { + phash = inet_ehashfn(net, daddr, hnum, saddr, sport); + reuse_sk = reuseport_select_sock(sk, phash, skb, doff); + } + return reuse_sk; +} + +/* + * Here are some nice properties to exploit here. The BSD API + * does not allow a listening sock to specify the remote port nor the + * remote address for the connection. So always assume those are both + * wildcarded during the search since they can never be otherwise. + */ + +/* called with rcu_read_lock() : No refcount taken on the socket */ +static struct sock *inet_lhash2_lookup(struct net *net, + struct inet_listen_hashbucket *ilb2, + struct sk_buff *skb, int doff, + const __be32 saddr, __be16 sport, + const __be32 daddr, const unsigned short hnum, + const int dif, const int sdif) +{ + struct inet_connection_sock *icsk; + struct sock *sk, *result = NULL; + int score, hiscore = 0; + + inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) { + sk = (struct sock *)icsk; + score = compute_score(sk, net, hnum, daddr, dif, sdif); + if (score > hiscore) { + result = lookup_reuseport(net, sk, skb, doff, + saddr, sport, daddr, hnum); + if (result) + return result; + + result = sk; + hiscore = score; + } + } + + return result; +} + +static inline struct sock *inet_lookup_run_bpf(struct net *net, + struct inet_hashinfo *hashinfo, + struct sk_buff *skb, int doff, + __be32 saddr, __be16 sport, + __be32 daddr, u16 hnum) +{ + struct sock *sk, *reuse_sk; + bool no_reuseport; + + if (hashinfo != &tcp_hashinfo) + return NULL; /* only TCP is supported */ + + no_reuseport = bpf_sk_lookup_run_v4(net, IPPROTO_TCP, + saddr, sport, daddr, hnum, &sk); + if (no_reuseport || IS_ERR_OR_NULL(sk)) + return sk; + + reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum); + if (reuse_sk) + sk = reuse_sk; + return sk; +} + +struct sock *__inet_lookup_listener(struct net *net, + struct inet_hashinfo *hashinfo, + struct sk_buff *skb, int doff, + const __be32 saddr, __be16 sport, + const __be32 daddr, const unsigned short hnum, + const int dif, const int sdif) +{ + struct inet_listen_hashbucket *ilb2; + struct sock *result = NULL; + unsigned int hash2; + + /* Lookup redirect from BPF */ + if (static_branch_unlikely(&bpf_sk_lookup_enabled)) { + result = inet_lookup_run_bpf(net, hashinfo, skb, doff, + saddr, sport, daddr, hnum); + if (result) + goto done; + } + + hash2 = ipv4_portaddr_hash(net, daddr, hnum); + ilb2 = inet_lhash2_bucket(hashinfo, hash2); + + result = inet_lhash2_lookup(net, ilb2, skb, doff, + saddr, sport, daddr, hnum, + dif, sdif); + if (result) + goto done; + + /* Lookup lhash2 with INADDR_ANY */ + hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum); + ilb2 = inet_lhash2_bucket(hashinfo, hash2); + + result = inet_lhash2_lookup(net, ilb2, skb, doff, + saddr, sport, htonl(INADDR_ANY), hnum, + dif, sdif); +done: + if (IS_ERR(result)) + return NULL; + return result; +} +EXPORT_SYMBOL_GPL(__inet_lookup_listener); + +/* All sockets share common refcount, but have different destructors */ +void sock_gen_put(struct sock *sk) +{ + if (!refcount_dec_and_test(&sk->sk_refcnt)) + return; + + if (sk->sk_state == TCP_TIME_WAIT) + inet_twsk_free(inet_twsk(sk)); + else if (sk->sk_state == TCP_NEW_SYN_RECV) + reqsk_free(inet_reqsk(sk)); + else + sk_free(sk); +} +EXPORT_SYMBOL_GPL(sock_gen_put); + +void sock_edemux(struct sk_buff *skb) +{ + sock_gen_put(skb->sk); +} +EXPORT_SYMBOL(sock_edemux); + +struct sock *__inet_lookup_established(struct net *net, + struct inet_hashinfo *hashinfo, + const __be32 saddr, const __be16 sport, + const __be32 daddr, const u16 hnum, + const int dif, const int sdif) +{ + INET_ADDR_COOKIE(acookie, saddr, daddr); + const __portpair ports = INET_COMBINED_PORTS(sport, hnum); + struct sock *sk; + const struct hlist_nulls_node *node; + /* Optimize here for direct hit, only listening connections can + * have wildcards anyways. + */ + unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport); + unsigned int slot = hash & hashinfo->ehash_mask; + struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; + +begin: + sk_nulls_for_each_rcu(sk, node, &head->chain) { + if (sk->sk_hash != hash) + continue; + if (likely(INET_MATCH(net, sk, acookie, ports, dif, sdif))) { + if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) + goto out; + if (unlikely(!INET_MATCH(net, sk, acookie, + ports, dif, sdif))) { + sock_gen_put(sk); + goto begin; + } + goto found; + } + } + /* + * 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(node) != slot) + goto begin; +out: + sk = NULL; +found: + return sk; +} +EXPORT_SYMBOL_GPL(__inet_lookup_established); + +/* called with local bh disabled */ +static int __inet_check_established(struct inet_timewait_death_row *death_row, + struct sock *sk, __u16 lport, + struct inet_timewait_sock **twp) +{ + struct inet_hashinfo *hinfo = death_row->hashinfo; + struct inet_sock *inet = inet_sk(sk); + __be32 daddr = inet->inet_rcv_saddr; + __be32 saddr = inet->inet_daddr; + int dif = sk->sk_bound_dev_if; + struct net *net = sock_net(sk); + int sdif = l3mdev_master_ifindex_by_index(net, dif); + INET_ADDR_COOKIE(acookie, saddr, daddr); + const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); + unsigned int hash = inet_ehashfn(net, daddr, lport, + saddr, inet->inet_dport); + struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); + spinlock_t *lock = inet_ehash_lockp(hinfo, hash); + struct sock *sk2; + const struct hlist_nulls_node *node; + struct inet_timewait_sock *tw = NULL; + + spin_lock(lock); + + sk_nulls_for_each(sk2, node, &head->chain) { + if (sk2->sk_hash != hash) + continue; + + if (likely(INET_MATCH(net, sk2, acookie, ports, dif, sdif))) { + if (sk2->sk_state == TCP_TIME_WAIT) { + tw = inet_twsk(sk2); + if (twsk_unique(sk, sk2, twp)) + break; + } + goto not_unique; + } + } + + /* Must record num and sport now. Otherwise we will see + * in hash table socket with a funny identity. + */ + inet->inet_num = lport; + inet->inet_sport = htons(lport); + sk->sk_hash = hash; + WARN_ON(!sk_unhashed(sk)); + __sk_nulls_add_node_rcu(sk, &head->chain); + if (tw) { + sk_nulls_del_node_init_rcu((struct sock *)tw); + __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED); + } + spin_unlock(lock); + sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); + + if (twp) { + *twp = tw; + } else if (tw) { + /* Silly. Should hash-dance instead... */ + inet_twsk_deschedule_put(tw); + } + return 0; + +not_unique: + spin_unlock(lock); + return -EADDRNOTAVAIL; +} + +static u64 inet_sk_port_offset(const struct sock *sk) +{ + const struct inet_sock *inet = inet_sk(sk); + + return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr, + inet->inet_daddr, + inet->inet_dport); +} + +/* Searches for an exsiting socket in the ehash bucket list. + * Returns true if found, false otherwise. + */ +static bool inet_ehash_lookup_by_sk(struct sock *sk, + struct hlist_nulls_head *list) +{ + const __portpair ports = INET_COMBINED_PORTS(sk->sk_dport, sk->sk_num); + const int sdif = sk->sk_bound_dev_if; + const int dif = sk->sk_bound_dev_if; + const struct hlist_nulls_node *node; + struct net *net = sock_net(sk); + struct sock *esk; + + INET_ADDR_COOKIE(acookie, sk->sk_daddr, sk->sk_rcv_saddr); + + sk_nulls_for_each_rcu(esk, node, list) { + if (esk->sk_hash != sk->sk_hash) + continue; + if (sk->sk_family == AF_INET) { + if (unlikely(INET_MATCH(net, esk, acookie, + ports, dif, sdif))) { + return true; + } + } +#if IS_ENABLED(CONFIG_IPV6) + else if (sk->sk_family == AF_INET6) { + if (unlikely(inet6_match(net, esk, + &sk->sk_v6_daddr, + &sk->sk_v6_rcv_saddr, + ports, dif, sdif))) { + return true; + } + } +#endif + } + return false; +} + +/* Insert a socket into ehash, and eventually remove another one + * (The another one can be a SYN_RECV or TIMEWAIT) + * If an existing socket already exists, socket sk is not inserted, + * and sets found_dup_sk parameter to true. + */ +bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk) +{ + struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; + struct hlist_nulls_head *list; + struct inet_ehash_bucket *head; + spinlock_t *lock; + bool ret = true; + + WARN_ON_ONCE(!sk_unhashed(sk)); + + sk->sk_hash = sk_ehashfn(sk); + head = inet_ehash_bucket(hashinfo, sk->sk_hash); + list = &head->chain; + lock = inet_ehash_lockp(hashinfo, sk->sk_hash); + + spin_lock(lock); + if (osk) { + WARN_ON_ONCE(sk->sk_hash != osk->sk_hash); + ret = sk_nulls_del_node_init_rcu(osk); + } else if (found_dup_sk) { + *found_dup_sk = inet_ehash_lookup_by_sk(sk, list); + if (*found_dup_sk) + ret = false; + } + + if (ret) + __sk_nulls_add_node_rcu(sk, list); + + spin_unlock(lock); + + return ret; +} + +bool inet_ehash_nolisten(struct sock *sk, struct sock *osk, bool *found_dup_sk) +{ + bool ok = inet_ehash_insert(sk, osk, found_dup_sk); + + if (ok) { + sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); + } else { + this_cpu_inc(*sk->sk_prot->orphan_count); + inet_sk_set_state(sk, TCP_CLOSE); + sock_set_flag(sk, SOCK_DEAD); + inet_csk_destroy_sock(sk); + } + return ok; +} +EXPORT_SYMBOL_GPL(inet_ehash_nolisten); + +static int inet_reuseport_add_sock(struct sock *sk, + struct inet_listen_hashbucket *ilb) +{ + struct inet_bind_bucket *tb = inet_csk(sk)->icsk_bind_hash; + const struct hlist_nulls_node *node; + struct sock *sk2; + kuid_t uid = sock_i_uid(sk); + + sk_nulls_for_each_rcu(sk2, node, &ilb->nulls_head) { + if (sk2 != sk && + sk2->sk_family == sk->sk_family && + ipv6_only_sock(sk2) == ipv6_only_sock(sk) && + sk2->sk_bound_dev_if == sk->sk_bound_dev_if && + inet_csk(sk2)->icsk_bind_hash == tb && + sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) && + inet_rcv_saddr_equal(sk, sk2, false)) + return reuseport_add_sock(sk, sk2, + inet_rcv_saddr_any(sk)); + } + + return reuseport_alloc(sk, inet_rcv_saddr_any(sk)); +} + +int __inet_hash(struct sock *sk, struct sock *osk) +{ + struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; + struct inet_listen_hashbucket *ilb; + int err = 0; + + if (sk->sk_state != TCP_LISTEN) { + local_bh_disable(); + inet_ehash_nolisten(sk, osk, NULL); + local_bh_enable(); + return 0; + } + WARN_ON(!sk_unhashed(sk)); + ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; + + spin_lock(&ilb->lock); + if (sk->sk_reuseport) { + err = inet_reuseport_add_sock(sk, ilb); + if (err) + goto unlock; + } + if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport && + sk->sk_family == AF_INET6) + __sk_nulls_add_node_tail_rcu(sk, &ilb->nulls_head); + else + __sk_nulls_add_node_rcu(sk, &ilb->nulls_head); + inet_hash2(hashinfo, sk); + ilb->count++; + sock_set_flag(sk, SOCK_RCU_FREE); + sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); +unlock: + spin_unlock(&ilb->lock); + + return err; +} +EXPORT_SYMBOL(__inet_hash); + +int inet_hash(struct sock *sk) +{ + int err = 0; + + if (sk->sk_state != TCP_CLOSE) + err = __inet_hash(sk, NULL); + + return err; +} +EXPORT_SYMBOL_GPL(inet_hash); + +static void __inet_unhash(struct sock *sk, struct inet_listen_hashbucket *ilb) +{ + if (sk_unhashed(sk)) + return; + + if (rcu_access_pointer(sk->sk_reuseport_cb)) + reuseport_detach_sock(sk); + if (ilb) { + struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; + + inet_unhash2(hashinfo, sk); + ilb->count--; + } + __sk_nulls_del_node_init_rcu(sk); + sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); +} + +void inet_unhash(struct sock *sk) +{ + struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; + + if (sk_unhashed(sk)) + return; + + if (sk->sk_state == TCP_LISTEN) { + struct inet_listen_hashbucket *ilb; + + ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; + /* Don't disable bottom halves while acquiring the lock to + * avoid circular locking dependency on PREEMPT_RT. + */ + spin_lock(&ilb->lock); + __inet_unhash(sk, ilb); + spin_unlock(&ilb->lock); + } else { + spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash); + + spin_lock_bh(lock); + __inet_unhash(sk, NULL); + spin_unlock_bh(lock); + } +} +EXPORT_SYMBOL_GPL(inet_unhash); + +/* RFC 6056 3.3.4. Algorithm 4: Double-Hash Port Selection Algorithm + * Note that we use 32bit integers (vs RFC 'short integers') + * because 2^16 is not a multiple of num_ephemeral and this + * property might be used by clever attacker. + * + * RFC claims using TABLE_LENGTH=10 buckets gives an improvement, though + * attacks were since demonstrated, thus we use 65536 by default instead + * to really give more isolation and privacy, at the expense of 256kB + * of kernel memory. + */ +#define INET_TABLE_PERTURB_SIZE (1 << CONFIG_INET_TABLE_PERTURB_ORDER) +static u32 *table_perturb; + +int __inet_hash_connect(struct inet_timewait_death_row *death_row, + struct sock *sk, u64 port_offset, + int (*check_established)(struct inet_timewait_death_row *, + struct sock *, __u16, struct inet_timewait_sock **)) +{ + struct inet_hashinfo *hinfo = death_row->hashinfo; + struct inet_timewait_sock *tw = NULL; + struct inet_bind_hashbucket *head; + int port = inet_sk(sk)->inet_num; + struct net *net = sock_net(sk); + struct inet_bind_bucket *tb; + u32 remaining, offset; + int ret, i, low, high; + int l3mdev; + u32 index; + + if (port) { + local_bh_disable(); + ret = check_established(death_row, sk, port, NULL); + local_bh_enable(); + return ret; + } + + l3mdev = inet_sk_bound_l3mdev(sk); + + inet_get_local_port_range(net, &low, &high); + high++; /* [32768, 60999] -> [32768, 61000[ */ + remaining = high - low; + if (likely(remaining > 1)) + remaining &= ~1U; + + get_random_slow_once(table_perturb, + INET_TABLE_PERTURB_SIZE * sizeof(*table_perturb)); + index = port_offset & (INET_TABLE_PERTURB_SIZE - 1); + + offset = READ_ONCE(table_perturb[index]) + (port_offset >> 32); + offset %= remaining; + + /* In first pass we try ports of @low parity. + * inet_csk_get_port() does the opposite choice. + */ + offset &= ~1U; +other_parity_scan: + port = low + offset; + for (i = 0; i < remaining; i += 2, port += 2) { + if (unlikely(port >= high)) + port -= remaining; + if (inet_is_local_reserved_port(net, port)) + continue; + head = &hinfo->bhash[inet_bhashfn(net, port, + hinfo->bhash_size)]; + spin_lock_bh(&head->lock); + + /* Does not bother with rcv_saddr checks, because + * the established check is already unique enough. + */ + inet_bind_bucket_for_each(tb, &head->chain) { + if (net_eq(ib_net(tb), net) && tb->l3mdev == l3mdev && + tb->port == port) { + if (tb->fastreuse >= 0 || + tb->fastreuseport >= 0) + goto next_port; + WARN_ON(hlist_empty(&tb->owners)); + if (!check_established(death_row, sk, + port, &tw)) + goto ok; + goto next_port; + } + } + + tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, + net, head, port, l3mdev); + if (!tb) { + spin_unlock_bh(&head->lock); + return -ENOMEM; + } + tb->fastreuse = -1; + tb->fastreuseport = -1; + goto ok; +next_port: + spin_unlock_bh(&head->lock); + cond_resched(); + } + + offset++; + if ((offset & 1) && remaining > 1) + goto other_parity_scan; + + return -EADDRNOTAVAIL; + +ok: + /* Here we want to add a little bit of randomness to the next source + * port that will be chosen. We use a max() with a random here so that + * on low contention the randomness is maximal and on high contention + * it may be inexistent. + */ + i = max_t(int, i, (prandom_u32() & 7) * 2); + WRITE_ONCE(table_perturb[index], READ_ONCE(table_perturb[index]) + i + 2); + + /* Head lock still held and bh's disabled */ + inet_bind_hash(sk, tb, port); + if (sk_unhashed(sk)) { + inet_sk(sk)->inet_sport = htons(port); + inet_ehash_nolisten(sk, (struct sock *)tw, NULL); + } + if (tw) + inet_twsk_bind_unhash(tw, hinfo); + spin_unlock(&head->lock); + if (tw) + inet_twsk_deschedule_put(tw); + local_bh_enable(); + return 0; +} + +/* + * Bind a port for a connect operation and hash it. + */ +int inet_hash_connect(struct inet_timewait_death_row *death_row, + struct sock *sk) +{ + u64 port_offset = 0; + + if (!inet_sk(sk)->inet_num) + port_offset = inet_sk_port_offset(sk); + return __inet_hash_connect(death_row, sk, port_offset, + __inet_check_established); +} +EXPORT_SYMBOL_GPL(inet_hash_connect); + +void inet_hashinfo_init(struct inet_hashinfo *h) +{ + int i; + + for (i = 0; i < INET_LHTABLE_SIZE; i++) { + spin_lock_init(&h->listening_hash[i].lock); + INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].nulls_head, + i + LISTENING_NULLS_BASE); + h->listening_hash[i].count = 0; + } + + h->lhash2 = NULL; +} +EXPORT_SYMBOL_GPL(inet_hashinfo_init); + +static void init_hashinfo_lhash2(struct inet_hashinfo *h) +{ + int i; + + for (i = 0; i <= h->lhash2_mask; i++) { + spin_lock_init(&h->lhash2[i].lock); + INIT_HLIST_HEAD(&h->lhash2[i].head); + h->lhash2[i].count = 0; + } +} + +void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name, + unsigned long numentries, int scale, + unsigned long low_limit, + unsigned long high_limit) +{ + h->lhash2 = alloc_large_system_hash(name, + sizeof(*h->lhash2), + numentries, + scale, + 0, + NULL, + &h->lhash2_mask, + low_limit, + high_limit); + init_hashinfo_lhash2(h); + + /* this one is used for source ports of outgoing connections */ + table_perturb = kmalloc_array(INET_TABLE_PERTURB_SIZE, + sizeof(*table_perturb), GFP_KERNEL); + if (!table_perturb) + panic("TCP: failed to alloc table_perturb"); +} + +int inet_hashinfo2_init_mod(struct inet_hashinfo *h) +{ + h->lhash2 = kmalloc_array(INET_LHTABLE_SIZE, sizeof(*h->lhash2), GFP_KERNEL); + if (!h->lhash2) + return -ENOMEM; + + h->lhash2_mask = INET_LHTABLE_SIZE - 1; + /* INET_LHTABLE_SIZE must be a power of 2 */ + BUG_ON(INET_LHTABLE_SIZE & h->lhash2_mask); + + init_hashinfo_lhash2(h); + return 0; +} +EXPORT_SYMBOL_GPL(inet_hashinfo2_init_mod); + +int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo) +{ + unsigned int locksz = sizeof(spinlock_t); + unsigned int i, nblocks = 1; + + if (locksz != 0) { + /* allocate 2 cache lines or at least one spinlock per cpu */ + nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U); + nblocks = roundup_pow_of_two(nblocks * num_possible_cpus()); + + /* no more locks than number of hash buckets */ + nblocks = min(nblocks, hashinfo->ehash_mask + 1); + + hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL); + if (!hashinfo->ehash_locks) + return -ENOMEM; + + for (i = 0; i < nblocks; i++) + spin_lock_init(&hashinfo->ehash_locks[i]); + } + hashinfo->ehash_locks_mask = nblocks - 1; + return 0; +} +EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc); |