aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/wireguard/allowedips.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/net/wireguard/allowedips.c')
-rw-r--r--drivers/net/wireguard/allowedips.c377
1 files changed, 377 insertions, 0 deletions
diff --git a/drivers/net/wireguard/allowedips.c b/drivers/net/wireguard/allowedips.c
new file mode 100644
index 000000000000..f175944384cd
--- /dev/null
+++ b/drivers/net/wireguard/allowedips.c
@@ -0,0 +1,377 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include "allowedips.h"
+#include "peer.h"
+
+static void swap_endian(u8 *dst, const u8 *src, u8 bits)
+{
+ if (bits == 32) {
+ *(u32 *)dst = be32_to_cpu(*(const __be32 *)src);
+ } else if (bits == 128) {
+ ((u64 *)dst)[0] = be64_to_cpu(((const __be64 *)src)[0]);
+ ((u64 *)dst)[1] = be64_to_cpu(((const __be64 *)src)[1]);
+ }
+}
+
+static void copy_and_assign_cidr(struct allowedips_node *node, const u8 *src,
+ u8 cidr, u8 bits)
+{
+ node->cidr = cidr;
+ node->bit_at_a = cidr / 8U;
+#ifdef __LITTLE_ENDIAN
+ node->bit_at_a ^= (bits / 8U - 1U) % 8U;
+#endif
+ node->bit_at_b = 7U - (cidr % 8U);
+ node->bitlen = bits;
+ memcpy(node->bits, src, bits / 8U);
+}
+#define CHOOSE_NODE(parent, key) \
+ parent->bit[(key[parent->bit_at_a] >> parent->bit_at_b) & 1]
+
+static void node_free_rcu(struct rcu_head *rcu)
+{
+ kfree(container_of(rcu, struct allowedips_node, rcu));
+}
+
+static void push_rcu(struct allowedips_node **stack,
+ struct allowedips_node __rcu *p, unsigned int *len)
+{
+ if (rcu_access_pointer(p)) {
+ WARN_ON(IS_ENABLED(DEBUG) && *len >= 128);
+ stack[(*len)++] = rcu_dereference_raw(p);
+ }
+}
+
+static void root_free_rcu(struct rcu_head *rcu)
+{
+ struct allowedips_node *node, *stack[128] = {
+ container_of(rcu, struct allowedips_node, rcu) };
+ unsigned int len = 1;
+
+ while (len > 0 && (node = stack[--len])) {
+ push_rcu(stack, node->bit[0], &len);
+ push_rcu(stack, node->bit[1], &len);
+ kfree(node);
+ }
+}
+
+static void root_remove_peer_lists(struct allowedips_node *root)
+{
+ struct allowedips_node *node, *stack[128] = { root };
+ unsigned int len = 1;
+
+ while (len > 0 && (node = stack[--len])) {
+ push_rcu(stack, node->bit[0], &len);
+ push_rcu(stack, node->bit[1], &len);
+ if (rcu_access_pointer(node->peer))
+ list_del(&node->peer_list);
+ }
+}
+
+static void walk_remove_by_peer(struct allowedips_node __rcu **top,
+ struct wg_peer *peer, struct mutex *lock)
+{
+#define REF(p) rcu_access_pointer(p)
+#define DEREF(p) rcu_dereference_protected(*(p), lockdep_is_held(lock))
+#define PUSH(p) ({ \
+ WARN_ON(IS_ENABLED(DEBUG) && len >= 128); \
+ stack[len++] = p; \
+ })
+
+ struct allowedips_node __rcu **stack[128], **nptr;
+ struct allowedips_node *node, *prev;
+ unsigned int len;
+
+ if (unlikely(!peer || !REF(*top)))
+ return;
+
+ for (prev = NULL, len = 0, PUSH(top); len > 0; prev = node) {
+ nptr = stack[len - 1];
+ node = DEREF(nptr);
+ if (!node) {
+ --len;
+ continue;
+ }
+ if (!prev || REF(prev->bit[0]) == node ||
+ REF(prev->bit[1]) == node) {
+ if (REF(node->bit[0]))
+ PUSH(&node->bit[0]);
+ else if (REF(node->bit[1]))
+ PUSH(&node->bit[1]);
+ } else if (REF(node->bit[0]) == prev) {
+ if (REF(node->bit[1]))
+ PUSH(&node->bit[1]);
+ } else {
+ if (rcu_dereference_protected(node->peer,
+ lockdep_is_held(lock)) == peer) {
+ RCU_INIT_POINTER(node->peer, NULL);
+ list_del(&node->peer_list);
+ if (!node->bit[0] || !node->bit[1]) {
+ rcu_assign_pointer(*nptr, DEREF(
+ &node->bit[!REF(node->bit[0])]));
+ call_rcu(&node->rcu, node_free_rcu);
+ node = DEREF(nptr);
+ }
+ }
+ --len;
+ }
+ }
+
+#undef REF
+#undef DEREF
+#undef PUSH
+}
+
+static unsigned int fls128(u64 a, u64 b)
+{
+ return a ? fls64(a) + 64U : fls64(b);
+}
+
+static u8 common_bits(const struct allowedips_node *node, const u8 *key,
+ u8 bits)
+{
+ if (bits == 32)
+ return 32U - fls(*(const u32 *)node->bits ^ *(const u32 *)key);
+ else if (bits == 128)
+ return 128U - fls128(
+ *(const u64 *)&node->bits[0] ^ *(const u64 *)&key[0],
+ *(const u64 *)&node->bits[8] ^ *(const u64 *)&key[8]);
+ return 0;
+}
+
+static bool prefix_matches(const struct allowedips_node *node, const u8 *key,
+ u8 bits)
+{
+ /* This could be much faster if it actually just compared the common
+ * bits properly, by precomputing a mask bswap(~0 << (32 - cidr)), and
+ * the rest, but it turns out that common_bits is already super fast on
+ * modern processors, even taking into account the unfortunate bswap.
+ * So, we just inline it like this instead.
+ */
+ return common_bits(node, key, bits) >= node->cidr;
+}
+
+static struct allowedips_node *find_node(struct allowedips_node *trie, u8 bits,
+ const u8 *key)
+{
+ struct allowedips_node *node = trie, *found = NULL;
+
+ while (node && prefix_matches(node, key, bits)) {
+ if (rcu_access_pointer(node->peer))
+ found = node;
+ if (node->cidr == bits)
+ break;
+ node = rcu_dereference_bh(CHOOSE_NODE(node, key));
+ }
+ return found;
+}
+
+/* Returns a strong reference to a peer */
+static struct wg_peer *lookup(struct allowedips_node __rcu *root, u8 bits,
+ const void *be_ip)
+{
+ /* Aligned so it can be passed to fls/fls64 */
+ u8 ip[16] __aligned(__alignof(u64));
+ struct allowedips_node *node;
+ struct wg_peer *peer = NULL;
+
+ swap_endian(ip, be_ip, bits);
+
+ rcu_read_lock_bh();
+retry:
+ node = find_node(rcu_dereference_bh(root), bits, ip);
+ if (node) {
+ peer = wg_peer_get_maybe_zero(rcu_dereference_bh(node->peer));
+ if (!peer)
+ goto retry;
+ }
+ rcu_read_unlock_bh();
+ return peer;
+}
+
+static bool node_placement(struct allowedips_node __rcu *trie, const u8 *key,
+ u8 cidr, u8 bits, struct allowedips_node **rnode,
+ struct mutex *lock)
+{
+ struct allowedips_node *node = rcu_dereference_protected(trie,
+ lockdep_is_held(lock));
+ struct allowedips_node *parent = NULL;
+ bool exact = false;
+
+ while (node && node->cidr <= cidr && prefix_matches(node, key, bits)) {
+ parent = node;
+ if (parent->cidr == cidr) {
+ exact = true;
+ break;
+ }
+ node = rcu_dereference_protected(CHOOSE_NODE(parent, key),
+ lockdep_is_held(lock));
+ }
+ *rnode = parent;
+ return exact;
+}
+
+static int add(struct allowedips_node __rcu **trie, u8 bits, const u8 *key,
+ u8 cidr, struct wg_peer *peer, struct mutex *lock)
+{
+ struct allowedips_node *node, *parent, *down, *newnode;
+
+ if (unlikely(cidr > bits || !peer))
+ return -EINVAL;
+
+ if (!rcu_access_pointer(*trie)) {
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (unlikely(!node))
+ return -ENOMEM;
+ RCU_INIT_POINTER(node->peer, peer);
+ list_add_tail(&node->peer_list, &peer->allowedips_list);
+ copy_and_assign_cidr(node, key, cidr, bits);
+ rcu_assign_pointer(*trie, node);
+ return 0;
+ }
+ if (node_placement(*trie, key, cidr, bits, &node, lock)) {
+ rcu_assign_pointer(node->peer, peer);
+ list_move_tail(&node->peer_list, &peer->allowedips_list);
+ return 0;
+ }
+
+ newnode = kzalloc(sizeof(*newnode), GFP_KERNEL);
+ if (unlikely(!newnode))
+ return -ENOMEM;
+ RCU_INIT_POINTER(newnode->peer, peer);
+ list_add_tail(&newnode->peer_list, &peer->allowedips_list);
+ copy_and_assign_cidr(newnode, key, cidr, bits);
+
+ if (!node) {
+ down = rcu_dereference_protected(*trie, lockdep_is_held(lock));
+ } else {
+ down = rcu_dereference_protected(CHOOSE_NODE(node, key),
+ lockdep_is_held(lock));
+ if (!down) {
+ rcu_assign_pointer(CHOOSE_NODE(node, key), newnode);
+ return 0;
+ }
+ }
+ cidr = min(cidr, common_bits(down, key, bits));
+ parent = node;
+
+ if (newnode->cidr == cidr) {
+ rcu_assign_pointer(CHOOSE_NODE(newnode, down->bits), down);
+ if (!parent)
+ rcu_assign_pointer(*trie, newnode);
+ else
+ rcu_assign_pointer(CHOOSE_NODE(parent, newnode->bits),
+ newnode);
+ } else {
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (unlikely(!node)) {
+ kfree(newnode);
+ return -ENOMEM;
+ }
+ INIT_LIST_HEAD(&node->peer_list);
+ copy_and_assign_cidr(node, newnode->bits, cidr, bits);
+
+ rcu_assign_pointer(CHOOSE_NODE(node, down->bits), down);
+ rcu_assign_pointer(CHOOSE_NODE(node, newnode->bits), newnode);
+ if (!parent)
+ rcu_assign_pointer(*trie, node);
+ else
+ rcu_assign_pointer(CHOOSE_NODE(parent, node->bits),
+ node);
+ }
+ return 0;
+}
+
+void wg_allowedips_init(struct allowedips *table)
+{
+ table->root4 = table->root6 = NULL;
+ table->seq = 1;
+}
+
+void wg_allowedips_free(struct allowedips *table, struct mutex *lock)
+{
+ struct allowedips_node __rcu *old4 = table->root4, *old6 = table->root6;
+
+ ++table->seq;
+ RCU_INIT_POINTER(table->root4, NULL);
+ RCU_INIT_POINTER(table->root6, NULL);
+ if (rcu_access_pointer(old4)) {
+ root_remove_peer_lists(old4);
+ call_rcu(&rcu_dereference_protected(old4,
+ lockdep_is_held(lock))->rcu, root_free_rcu);
+ }
+ if (rcu_access_pointer(old6)) {
+ root_remove_peer_lists(old6);
+ call_rcu(&rcu_dereference_protected(old6,
+ lockdep_is_held(lock))->rcu, root_free_rcu);
+ }
+}
+
+int wg_allowedips_insert_v4(struct allowedips *table, const struct in_addr *ip,
+ u8 cidr, struct wg_peer *peer, struct mutex *lock)
+{
+ /* Aligned so it can be passed to fls */
+ u8 key[4] __aligned(__alignof(u32));
+
+ ++table->seq;
+ swap_endian(key, (const u8 *)ip, 32);
+ return add(&table->root4, 32, key, cidr, peer, lock);
+}
+
+int wg_allowedips_insert_v6(struct allowedips *table, const struct in6_addr *ip,
+ u8 cidr, struct wg_peer *peer, struct mutex *lock)
+{
+ /* Aligned so it can be passed to fls64 */
+ u8 key[16] __aligned(__alignof(u64));
+
+ ++table->seq;
+ swap_endian(key, (const u8 *)ip, 128);
+ return add(&table->root6, 128, key, cidr, peer, lock);
+}
+
+void wg_allowedips_remove_by_peer(struct allowedips *table,
+ struct wg_peer *peer, struct mutex *lock)
+{
+ ++table->seq;
+ walk_remove_by_peer(&table->root4, peer, lock);
+ walk_remove_by_peer(&table->root6, peer, lock);
+}
+
+int wg_allowedips_read_node(struct allowedips_node *node, u8 ip[16], u8 *cidr)
+{
+ const unsigned int cidr_bytes = DIV_ROUND_UP(node->cidr, 8U);
+ swap_endian(ip, node->bits, node->bitlen);
+ memset(ip + cidr_bytes, 0, node->bitlen / 8U - cidr_bytes);
+ if (node->cidr)
+ ip[cidr_bytes - 1U] &= ~0U << (-node->cidr % 8U);
+
+ *cidr = node->cidr;
+ return node->bitlen == 32 ? AF_INET : AF_INET6;
+}
+
+/* Returns a strong reference to a peer */
+struct wg_peer *wg_allowedips_lookup_dst(struct allowedips *table,
+ struct sk_buff *skb)
+{
+ if (skb->protocol == htons(ETH_P_IP))
+ return lookup(table->root4, 32, &ip_hdr(skb)->daddr);
+ else if (skb->protocol == htons(ETH_P_IPV6))
+ return lookup(table->root6, 128, &ipv6_hdr(skb)->daddr);
+ return NULL;
+}
+
+/* Returns a strong reference to a peer */
+struct wg_peer *wg_allowedips_lookup_src(struct allowedips *table,
+ struct sk_buff *skb)
+{
+ if (skb->protocol == htons(ETH_P_IP))
+ return lookup(table->root4, 32, &ip_hdr(skb)->saddr);
+ else if (skb->protocol == htons(ETH_P_IPV6))
+ return lookup(table->root6, 128, &ipv6_hdr(skb)->saddr);
+ return NULL;
+}
+
+#include "selftest/allowedips.c"