aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/src/hashtables.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/hashtables.c')
-rw-r--r--src/hashtables.c168
1 files changed, 0 insertions, 168 deletions
diff --git a/src/hashtables.c b/src/hashtables.c
deleted file mode 100644
index 0e5235d..0000000
--- a/src/hashtables.c
+++ /dev/null
@@ -1,168 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0
- *
- * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
- */
-
-#include "hashtables.h"
-#include "peer.h"
-#include "noise.h"
-
-static inline struct hlist_head *pubkey_bucket(struct pubkey_hashtable *table, const u8 pubkey[NOISE_PUBLIC_KEY_LEN])
-{
- /* siphash gives us a secure 64bit number based on a random key. Since the bits are
- * uniformly distributed, we can then mask off to get the bits we need.
- */
- return &table->hashtable[siphash(pubkey, NOISE_PUBLIC_KEY_LEN, &table->key) & (HASH_SIZE(table->hashtable) - 1)];
-}
-
-void pubkey_hashtable_init(struct pubkey_hashtable *table)
-{
- get_random_bytes(&table->key, sizeof(table->key));
- hash_init(table->hashtable);
- mutex_init(&table->lock);
-}
-
-void pubkey_hashtable_add(struct pubkey_hashtable *table, struct wireguard_peer *peer)
-{
- mutex_lock(&table->lock);
- hlist_add_head_rcu(&peer->pubkey_hash, pubkey_bucket(table, peer->handshake.remote_static));
- mutex_unlock(&table->lock);
-}
-
-void pubkey_hashtable_remove(struct pubkey_hashtable *table, struct wireguard_peer *peer)
-{
- mutex_lock(&table->lock);
- hlist_del_init_rcu(&peer->pubkey_hash);
- mutex_unlock(&table->lock);
-}
-
-/* Returns a strong reference to a peer */
-struct wireguard_peer *pubkey_hashtable_lookup(struct pubkey_hashtable *table, const u8 pubkey[NOISE_PUBLIC_KEY_LEN])
-{
- struct wireguard_peer *iter_peer, *peer = NULL;
-
- rcu_read_lock_bh();
- hlist_for_each_entry_rcu_bh(iter_peer, pubkey_bucket(table, pubkey), pubkey_hash) {
- if (!memcmp(pubkey, iter_peer->handshake.remote_static, NOISE_PUBLIC_KEY_LEN)) {
- peer = iter_peer;
- break;
- }
- }
- peer = peer_get(peer);
- rcu_read_unlock_bh();
- return peer;
-}
-
-static inline struct hlist_head *index_bucket(struct index_hashtable *table, const __le32 index)
-{
- /* Since the indices are random and thus all bits are uniformly distributed,
- * we can find its bucket simply by masking.
- */
- return &table->hashtable[(__force u32)index & (HASH_SIZE(table->hashtable) - 1)];
-}
-
-void index_hashtable_init(struct index_hashtable *table)
-{
- hash_init(table->hashtable);
- spin_lock_init(&table->lock);
-}
-
-/* At the moment, we limit ourselves to 2^20 total peers, which generally might amount to 2^20*3
- * items in this hashtable. The algorithm below works by picking a random number and testing it.
- * We can see that these limits mean we usually succeed pretty quickly:
- *
- * >>> def calculation(tries, size):
- * ... return (size / 2**32)**(tries - 1) * (1 - (size / 2**32))
- * ...
- * >>> calculation(1, 2**20 * 3)
- * 0.999267578125
- * >>> calculation(2, 2**20 * 3)
- * 0.0007318854331970215
- * >>> calculation(3, 2**20 * 3)
- * 5.360489012673497e-07
- * >>> calculation(4, 2**20 * 3)
- * 3.9261394135792216e-10
- *
- * At the moment, we don't do any masking, so this algorithm isn't exactly constant time in
- * either the random guessing or in the hash list lookup. We could require a minimum of 3
- * tries, which would successfully mask the guessing. TODO: this would not, however, help
- * with the growing hash lengths.
- */
-
-__le32 index_hashtable_insert(struct index_hashtable *table, struct index_hashtable_entry *entry)
-{
- struct index_hashtable_entry *existing_entry;
-
- spin_lock_bh(&table->lock);
- hlist_del_init_rcu(&entry->index_hash);
- spin_unlock_bh(&table->lock);
-
- rcu_read_lock_bh();
-
-search_unused_slot:
- /* First we try to find an unused slot, randomly, while unlocked. */
- entry->index = (__force __le32)get_random_u32();
- hlist_for_each_entry_rcu_bh(existing_entry, index_bucket(table, entry->index), index_hash) {
- if (existing_entry->index == entry->index)
- goto search_unused_slot; /* If it's already in use, we continue searching. */
- }
-
- /* Once we've found an unused slot, we lock it, and then double-check
- * that nobody else stole it from us.
- */
- spin_lock_bh(&table->lock);
- hlist_for_each_entry_rcu_bh(existing_entry, index_bucket(table, entry->index), index_hash) {
- if (existing_entry->index == entry->index) {
- spin_unlock_bh(&table->lock);
- goto search_unused_slot; /* If it was stolen, we start over. */
- }
- }
- /* Otherwise, we know we have it exclusively (since we're locked), so we insert. */
- hlist_add_head_rcu(&entry->index_hash, index_bucket(table, entry->index));
- spin_unlock_bh(&table->lock);
-
- rcu_read_unlock_bh();
-
- return entry->index;
-}
-
-bool index_hashtable_replace(struct index_hashtable *table, struct index_hashtable_entry *old, struct index_hashtable_entry *new)
-{
- if (unlikely(hlist_unhashed(&old->index_hash)))
- return false;
- spin_lock_bh(&table->lock);
- new->index = old->index;
- hlist_replace_rcu(&old->index_hash, &new->index_hash);
- INIT_HLIST_NODE(&old->index_hash);
- spin_unlock_bh(&table->lock);
- return true;
-}
-
-void index_hashtable_remove(struct index_hashtable *table, struct index_hashtable_entry *entry)
-{
- spin_lock_bh(&table->lock);
- hlist_del_init_rcu(&entry->index_hash);
- spin_unlock_bh(&table->lock);
-}
-
-/* Returns a strong reference to a entry->peer */
-struct index_hashtable_entry *index_hashtable_lookup(struct index_hashtable *table, const enum index_hashtable_type type_mask, const __le32 index)
-{
- struct index_hashtable_entry *iter_entry, *entry = NULL;
-
- rcu_read_lock_bh();
- hlist_for_each_entry_rcu_bh(iter_entry, index_bucket(table, index), index_hash) {
- if (iter_entry->index == index) {
- if (likely(iter_entry->type & type_mask))
- entry = iter_entry;
- break;
- }
- }
- if (likely(entry)) {
- entry->peer = peer_get(entry->peer);
- if (unlikely(!entry->peer))
- entry = NULL;
- }
- rcu_read_unlock_bh();
- return entry;
-}