net: WireGuard secure network tunnel

WireGuard is a layer 3 secure networking tunnel made specifically for
the kernel, that aims to be much simpler and easier to audit than IPsec.
Extensive documentation and description of the protocol and
considerations, along with formal proofs of the cryptography, are
available at:

  * https://www.wireguard.com/
  * https://www.wireguard.com/papers/wireguard.pdf

This commit implements WireGuard as a simple network device driver,
accessible in the usual RTNL way used by virtual network drivers. It
makes use of the udp_tunnel APIs, GRO, GSO, NAPI, and the usual set of
networking subsystem APIs. It has a somewhat novel multicore queueing
system designed for maximum throughput and minimal latency of encryption
operations, but it is implemented modestly using workqueues and NAPI.
Configuration is done via generic Netlink, and following a review from
the Netlink maintainer a year ago, several high profile userspace tools
have already implemented the API.

This commit also comes with several different tests, both in-kernel
tests and out-of-kernel tests based on network namespaces, taking profit
of the fact that sockets used by WireGuard intentionally stay in the
namespace the WireGuard interface was originally created, exactly like
the semantics of userspace tun devices. See wireguard.com/netns/ for
pictures and examples.

The source code is fairly short, but rather than combining everything
into a single file, WireGuard is developed as cleanly separable files,
making auditing and comprehension easier. Things are laid out as
follows:

  * noise.[ch], cookie.[ch], messages.h: These implement the bulk of the
    cryptographic aspects of the protocol, and are mostly data-only in
    nature, taking in buffers of bytes and spitting out buffers of
    bytes. They also handle reference counting for their various shared
    pieces of data, like keys and key lists.

  * ratelimiter.[ch]: Used as an integral part of cookie.[ch] for
    ratelimiting certain types of cryptographic operations in accordance
    with particular WireGuard semantics.

  * allowedips.[ch], peerlookup.[ch]: The main lookup structures of
    WireGuard, the former being trie-like with particular semantics, an
    integral part of the design of the protocol, and the latter just
    being nice helper functions around the various hashtables we use.

  * device.[ch]: Implementation of functions for the netdevice and for
    rtnl, responsible for maintaining the life of a given interface and
    wiring it up to the rest of WireGuard.

  * peer.[ch]: Each interface has a list of peers, with helper functions
    available here for creation, destruction, and reference counting.

  * socket.[ch]: Implementation of functions related to udp_socket and
    the general set of kernel socket APIs, for sending and receiving
    ciphertext UDP packets, and taking care of WireGuard-specific sticky
    socket routing semantics for the automatic roaming.

  * netlink.[ch]: Userspace API entry point for configuring WireGuard
    peers and devices. The API has been implemented by several userspace
    tools and network management utility, and the WireGuard project
    distributes the basic wg(8) tool.

  * queueing.[ch]: Shared function on the rx and tx path for handling
    the various queues used in the multicore algorithms.

  * send.c: Handles encrypting outgoing packets in parallel on
    multiple cores, before sending them in order on a single core, via
    workqueues and ring buffers. Also handles sending handshake and cookie
    messages as part of the protocol, in parallel.

  * receive.c: Handles decrypting incoming packets in parallel on
    multiple cores, before passing them off in order to be ingested via
    the rest of the networking subsystem with GRO via the typical NAPI
    poll function. Also handles receiving handshake and cookie messages
    as part of the protocol, in parallel.

  * timers.[ch]: Uses the timer wheel to implement protocol particular
    event timeouts, and gives a set of very simple event-driven entry
    point functions for callers.

  * main.c, version.h: Initialization and deinitialization of the module.

  * selftest/*.h: Runtime unit tests for some of the most security
    sensitive functions.

  * tools/testing/selftests/wireguard/netns.sh: Aforementioned testing
    script using network namespaces.

This commit aims to be as self-contained as possible, implementing
WireGuard as a standalone module not needing much special handling or
coordination from the network subsystem. I expect for future
optimizations to the network stack to positively improve WireGuard, and
vice-versa, but for the time being, this exists as intentionally
standalone.

We introduce a menu option for CONFIG_WIREGUARD, as well as providing a
verbose debug log and self-tests via CONFIG_WIREGUARD_DEBUG.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: David Miller <davem@davemloft.net>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 683 insertions, 0 deletions

diff --git a/drivers/net/wireguard/selftest/allowedips.c b/drivers/net/wireguard/selftest/allowedips.c
new file mode 100644
index 000000000000..846db14cb046
--- /dev/null
+++ b/drivers/net/wireguard/selftest/allowedips.c
@@ -0,0 +1,683 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This contains some basic static unit tests for the allowedips data structure.
+ * It also has two additional modes that are disabled and meant to be used by
+ * folks directly playing with this file. If you define the macro
+ * DEBUG_PRINT_TRIE_GRAPHVIZ to be 1, then every time there's a full tree in
+ * memory, it will be printed out as KERN_DEBUG in a format that can be passed
+ * to graphviz (the dot command) to visualize it. If you define the macro
+ * DEBUG_RANDOM_TRIE to be 1, then there will be an extremely costly set of
+ * randomized tests done against a trivial implementation, which may take
+ * upwards of a half-hour to complete. There's no set of users who should be
+ * enabling these, and the only developers that should go anywhere near these
+ * nobs are the ones who are reading this comment.
+ */
+
+#ifdef DEBUG
+
+#include <linux/siphash.h>
+
+static __init void swap_endian_and_apply_cidr(u8 *dst, const u8 *src, u8 bits,
+					      u8 cidr)
+{
+	swap_endian(dst, src, bits);
+	memset(dst + (cidr + 7) / 8, 0, bits / 8 - (cidr + 7) / 8);
+	if (cidr)
+		dst[(cidr + 7) / 8 - 1] &= ~0U << ((8 - (cidr % 8)) % 8);
+}
+
+static __init void print_node(struct allowedips_node *node, u8 bits)
+{
+	char *fmt_connection = KERN_DEBUG "\t\"%p/%d\" -> \"%p/%d\";\n";
+	char *fmt_declaration = KERN_DEBUG
+		"\t\"%p/%d\"[style=%s, color=\"#%06x\"];\n";
+	char *style = "dotted";
+	u8 ip1[16], ip2[16];
+	u32 color = 0;
+
+	if (bits == 32) {
+		fmt_connection = KERN_DEBUG "\t\"%pI4/%d\" -> \"%pI4/%d\";\n";
+		fmt_declaration = KERN_DEBUG
+			"\t\"%pI4/%d\"[style=%s, color=\"#%06x\"];\n";
+	} else if (bits == 128) {
+		fmt_connection = KERN_DEBUG "\t\"%pI6/%d\" -> \"%pI6/%d\";\n";
+		fmt_declaration = KERN_DEBUG
+			"\t\"%pI6/%d\"[style=%s, color=\"#%06x\"];\n";
+	}
+	if (node->peer) {
+		hsiphash_key_t key = { { 0 } };
+
+		memcpy(&key, &node->peer, sizeof(node->peer));
+		color = hsiphash_1u32(0xdeadbeef, &key) % 200 << 16 |
+			hsiphash_1u32(0xbabecafe, &key) % 200 << 8 |
+			hsiphash_1u32(0xabad1dea, &key) % 200;
+		style = "bold";
+	}
+	swap_endian_and_apply_cidr(ip1, node->bits, bits, node->cidr);
+	printk(fmt_declaration, ip1, node->cidr, style, color);
+	if (node->bit[0]) {
+		swap_endian_and_apply_cidr(ip2,
+				rcu_dereference_raw(node->bit[0])->bits, bits,
+				node->cidr);
+		printk(fmt_connection, ip1, node->cidr, ip2,
+		       rcu_dereference_raw(node->bit[0])->cidr);
+		print_node(rcu_dereference_raw(node->bit[0]), bits);
+	}
+	if (node->bit[1]) {
+		swap_endian_and_apply_cidr(ip2,
+				rcu_dereference_raw(node->bit[1])->bits,
+				bits, node->cidr);
+		printk(fmt_connection, ip1, node->cidr, ip2,
+		       rcu_dereference_raw(node->bit[1])->cidr);
+		print_node(rcu_dereference_raw(node->bit[1]), bits);
+	}
+}
+
+static __init void print_tree(struct allowedips_node __rcu *top, u8 bits)
+{
+	printk(KERN_DEBUG "digraph trie {\n");
+	print_node(rcu_dereference_raw(top), bits);
+	printk(KERN_DEBUG "}\n");
+}
+
+enum {
+	NUM_PEERS = 2000,
+	NUM_RAND_ROUTES = 400,
+	NUM_MUTATED_ROUTES = 100,
+	NUM_QUERIES = NUM_RAND_ROUTES * NUM_MUTATED_ROUTES * 30
+};
+
+struct horrible_allowedips {
+	struct hlist_head head;
+};
+
+struct horrible_allowedips_node {
+	struct hlist_node table;
+	union nf_inet_addr ip;
+	union nf_inet_addr mask;
+	u8 ip_version;
+	void *value;
+};
+
+static __init void horrible_allowedips_init(struct horrible_allowedips *table)
+{
+	INIT_HLIST_HEAD(&table->head);
+}
+
+static __init void horrible_allowedips_free(struct horrible_allowedips *table)
+{
+	struct horrible_allowedips_node *node;
+	struct hlist_node *h;
+
+	hlist_for_each_entry_safe(node, h, &table->head, table) {
+		hlist_del(&node->table);
+		kfree(node);
+	}
+}
+
+static __init inline union nf_inet_addr horrible_cidr_to_mask(u8 cidr)
+{
+	union nf_inet_addr mask;
+
+	memset(&mask, 0x00, 128 / 8);
+	memset(&mask, 0xff, cidr / 8);
+	if (cidr % 32)
+		mask.all[cidr / 32] = (__force u32)htonl(
+			(0xFFFFFFFFUL << (32 - (cidr % 32))) & 0xFFFFFFFFUL);
+	return mask;
+}
+
+static __init inline u8 horrible_mask_to_cidr(union nf_inet_addr subnet)
+{
+	return hweight32(subnet.all[0]) + hweight32(subnet.all[1]) +
+	       hweight32(subnet.all[2]) + hweight32(subnet.all[3]);
+}
+
+static __init inline void
+horrible_mask_self(struct horrible_allowedips_node *node)
+{
+	if (node->ip_version == 4) {
+		node->ip.ip &= node->mask.ip;
+	} else if (node->ip_version == 6) {
+		node->ip.ip6[0] &= node->mask.ip6[0];
+		node->ip.ip6[1] &= node->mask.ip6[1];
+		node->ip.ip6[2] &= node->mask.ip6[2];
+		node->ip.ip6[3] &= node->mask.ip6[3];
+	}
+}
+
+static __init inline bool
+horrible_match_v4(const struct horrible_allowedips_node *node,
+		  struct in_addr *ip)
+{
+	return (ip->s_addr & node->mask.ip) == node->ip.ip;
+}
+
+static __init inline bool
+horrible_match_v6(const struct horrible_allowedips_node *node,
+		  struct in6_addr *ip)
+{
+	return (ip->in6_u.u6_addr32[0] & node->mask.ip6[0]) ==
+		       node->ip.ip6[0] &&
+	       (ip->in6_u.u6_addr32[1] & node->mask.ip6[1]) ==
+		       node->ip.ip6[1] &&
+	       (ip->in6_u.u6_addr32[2] & node->mask.ip6[2]) ==
+		       node->ip.ip6[2] &&
+	       (ip->in6_u.u6_addr32[3] & node->mask.ip6[3]) == node->ip.ip6[3];
+}
+
+static __init void
+horrible_insert_ordered(struct horrible_allowedips *table,
+			struct horrible_allowedips_node *node)
+{
+	struct horrible_allowedips_node *other = NULL, *where = NULL;
+	u8 my_cidr = horrible_mask_to_cidr(node->mask);
+
+	hlist_for_each_entry(other, &table->head, table) {
+		if (!memcmp(&other->mask, &node->mask,
+			    sizeof(union nf_inet_addr)) &&
+		    !memcmp(&other->ip, &node->ip,
+			    sizeof(union nf_inet_addr)) &&
+		    other->ip_version == node->ip_version) {
+			other->value = node->value;
+			kfree(node);
+			return;
+		}
+		where = other;
+		if (horrible_mask_to_cidr(other->mask) <= my_cidr)
+			break;
+	}
+	if (!other && !where)
+		hlist_add_head(&node->table, &table->head);
+	else if (!other)
+		hlist_add_behind(&node->table, &where->table);
+	else
+		hlist_add_before(&node->table, &where->table);
+}
+
+static __init int
+horrible_allowedips_insert_v4(struct horrible_allowedips *table,
+			      struct in_addr *ip, u8 cidr, void *value)
+{
+	struct horrible_allowedips_node *node = kzalloc(sizeof(*node),
+							GFP_KERNEL);
+
+	if (unlikely(!node))
+		return -ENOMEM;
+	node->ip.in = *ip;
+	node->mask = horrible_cidr_to_mask(cidr);
+	node->ip_version = 4;
+	node->value = value;
+	horrible_mask_self(node);
+	horrible_insert_ordered(table, node);
+	return 0;
+}
+
+static __init int
+horrible_allowedips_insert_v6(struct horrible_allowedips *table,
+			      struct in6_addr *ip, u8 cidr, void *value)
+{
+	struct horrible_allowedips_node *node = kzalloc(sizeof(*node),
+							GFP_KERNEL);
+
+	if (unlikely(!node))
+		return -ENOMEM;
+	node->ip.in6 = *ip;
+	node->mask = horrible_cidr_to_mask(cidr);
+	node->ip_version = 6;
+	node->value = value;
+	horrible_mask_self(node);
+	horrible_insert_ordered(table, node);
+	return 0;
+}
+
+static __init void *
+horrible_allowedips_lookup_v4(struct horrible_allowedips *table,
+			      struct in_addr *ip)
+{
+	struct horrible_allowedips_node *node;
+	void *ret = NULL;
+
+	hlist_for_each_entry(node, &table->head, table) {
+		if (node->ip_version != 4)
+			continue;
+		if (horrible_match_v4(node, ip)) {
+			ret = node->value;
+			break;
+		}
+	}
+	return ret;
+}
+
+static __init void *
+horrible_allowedips_lookup_v6(struct horrible_allowedips *table,
+			      struct in6_addr *ip)
+{
+	struct horrible_allowedips_node *node;
+	void *ret = NULL;
+
+	hlist_for_each_entry(node, &table->head, table) {
+		if (node->ip_version != 6)
+			continue;
+		if (horrible_match_v6(node, ip)) {
+			ret = node->value;
+			break;
+		}
+	}
+	return ret;
+}
+
+static __init bool randomized_test(void)
+{
+	unsigned int i, j, k, mutate_amount, cidr;
+	u8 ip[16], mutate_mask[16], mutated[16];
+	struct wg_peer **peers, *peer;
+	struct horrible_allowedips h;
+	DEFINE_MUTEX(mutex);
+	struct allowedips t;
+	bool ret = false;
+
+	mutex_init(&mutex);
+
+	wg_allowedips_init(&t);
+	horrible_allowedips_init(&h);
+
+	peers = kcalloc(NUM_PEERS, sizeof(*peers), GFP_KERNEL);
+	if (unlikely(!peers)) {
+		pr_err("allowedips random self-test malloc: FAIL\n");
+		goto free;
+	}
+	for (i = 0; i < NUM_PEERS; ++i) {
+		peers[i] = kzalloc(sizeof(*peers[i]), GFP_KERNEL);
+		if (unlikely(!peers[i])) {
+			pr_err("allowedips random self-test malloc: FAIL\n");
+			goto free;
+		}
+		kref_init(&peers[i]->refcount);
+	}
+
+	mutex_lock(&mutex);
+
+	for (i = 0; i < NUM_RAND_ROUTES; ++i) {
+		prandom_bytes(ip, 4);
+		cidr = prandom_u32_max(32) + 1;
+		peer = peers[prandom_u32_max(NUM_PEERS)];
+		if (wg_allowedips_insert_v4(&t, (struct in_addr *)ip, cidr,
+					    peer, &mutex) < 0) {
+			pr_err("allowedips random self-test malloc: FAIL\n");
+			goto free_locked;
+		}
+		if (horrible_allowedips_insert_v4(&h, (struct in_addr *)ip,
+						  cidr, peer) < 0) {
+			pr_err("allowedips random self-test malloc: FAIL\n");
+			goto free_locked;
+		}
+		for (j = 0; j < NUM_MUTATED_ROUTES; ++j) {
+			memcpy(mutated, ip, 4);
+			prandom_bytes(mutate_mask, 4);
+			mutate_amount = prandom_u32_max(32);
+			for (k = 0; k < mutate_amount / 8; ++k)
+				mutate_mask[k] = 0xff;
+			mutate_mask[k] = 0xff
+					 << ((8 - (mutate_amount % 8)) % 8);
+			for (; k < 4; ++k)
+				mutate_mask[k] = 0;
+			for (k = 0; k < 4; ++k)
+				mutated[k] = (mutated[k] & mutate_mask[k]) |
+					     (~mutate_mask[k] &
+					      prandom_u32_max(256));
+			cidr = prandom_u32_max(32) + 1;
+			peer = peers[prandom_u32_max(NUM_PEERS)];
+			if (wg_allowedips_insert_v4(&t,
+						    (struct in_addr *)mutated,
+						    cidr, peer, &mutex) < 0) {
+				pr_err("allowedips random malloc: FAIL\n");
+				goto free_locked;
+			}
+			if (horrible_allowedips_insert_v4(&h,
+				(struct in_addr *)mutated, cidr, peer)) {
+				pr_err("allowedips random self-test malloc: FAIL\n");
+				goto free_locked;
+			}
+		}
+	}
+
+	for (i = 0; i < NUM_RAND_ROUTES; ++i) {
+		prandom_bytes(ip, 16);
+		cidr = prandom_u32_max(128) + 1;
+		peer = peers[prandom_u32_max(NUM_PEERS)];
+		if (wg_allowedips_insert_v6(&t, (struct in6_addr *)ip, cidr,
+					    peer, &mutex) < 0) {
+			pr_err("allowedips random self-test malloc: FAIL\n");
+			goto free_locked;
+		}
+		if (horrible_allowedips_insert_v6(&h, (struct in6_addr *)ip,
+						  cidr, peer) < 0) {
+			pr_err("allowedips random self-test malloc: FAIL\n");
+			goto free_locked;
+		}
+		for (j = 0; j < NUM_MUTATED_ROUTES; ++j) {
+			memcpy(mutated, ip, 16);
+			prandom_bytes(mutate_mask, 16);
+			mutate_amount = prandom_u32_max(128);
+			for (k = 0; k < mutate_amount / 8; ++k)
+				mutate_mask[k] = 0xff;
+			mutate_mask[k] = 0xff
+					 << ((8 - (mutate_amount % 8)) % 8);
+			for (; k < 4; ++k)
+				mutate_mask[k] = 0;
+			for (k = 0; k < 4; ++k)
+				mutated[k] = (mutated[k] & mutate_mask[k]) |
+					     (~mutate_mask[k] &
+					      prandom_u32_max(256));
+			cidr = prandom_u32_max(128) + 1;
+			peer = peers[prandom_u32_max(NUM_PEERS)];
+			if (wg_allowedips_insert_v6(&t,
+						    (struct in6_addr *)mutated,
+						    cidr, peer, &mutex) < 0) {
+				pr_err("allowedips random self-test malloc: FAIL\n");
+				goto free_locked;
+			}
+			if (horrible_allowedips_insert_v6(
+				    &h, (struct in6_addr *)mutated, cidr,
+				    peer)) {
+				pr_err("allowedips random self-test malloc: FAIL\n");
+				goto free_locked;
+			}
+		}
+	}
+
+	mutex_unlock(&mutex);
+
+	if (IS_ENABLED(DEBUG_PRINT_TRIE_GRAPHVIZ)) {
+		print_tree(t.root4, 32);
+		print_tree(t.root6, 128);
+	}
+
+	for (i = 0; i < NUM_QUERIES; ++i) {
+		prandom_bytes(ip, 4);
+		if (lookup(t.root4, 32, ip) !=
+		    horrible_allowedips_lookup_v4(&h, (struct in_addr *)ip)) {
+			pr_err("allowedips random self-test: FAIL\n");
+			goto free;
+		}
+	}
+
+	for (i = 0; i < NUM_QUERIES; ++i) {
+		prandom_bytes(ip, 16);
+		if (lookup(t.root6, 128, ip) !=
+		    horrible_allowedips_lookup_v6(&h, (struct in6_addr *)ip)) {
+			pr_err("allowedips random self-test: FAIL\n");
+			goto free;
+		}
+	}
+	ret = true;
+
+free:
+	mutex_lock(&mutex);
+free_locked:
+	wg_allowedips_free(&t, &mutex);
+	mutex_unlock(&mutex);
+	horrible_allowedips_free(&h);
+	if (peers) {
+		for (i = 0; i < NUM_PEERS; ++i)
+			kfree(peers[i]);
+	}
+	kfree(peers);
+	return ret;
+}
+
+static __init inline struct in_addr *ip4(u8 a, u8 b, u8 c, u8 d)
+{
+	static struct in_addr ip;
+	u8 *split = (u8 *)&ip;
+
+	split[0] = a;
+	split[1] = b;
+	split[2] = c;
+	split[3] = d;
+	return &ip;
+}
+
+static __init inline struct in6_addr *ip6(u32 a, u32 b, u32 c, u32 d)
+{
+	static struct in6_addr ip;
+	__be32 *split = (__be32 *)&ip;
+
+	split[0] = cpu_to_be32(a);
+	split[1] = cpu_to_be32(b);
+	split[2] = cpu_to_be32(c);
+	split[3] = cpu_to_be32(d);
+	return &ip;
+}
+
+static __init struct wg_peer *init_peer(void)
+{
+	struct wg_peer *peer = kzalloc(sizeof(*peer), GFP_KERNEL);
+
+	if (!peer)
+		return NULL;
+	kref_init(&peer->refcount);
+	INIT_LIST_HEAD(&peer->allowedips_list);
+	return peer;
+}
+
+#define insert(version, mem, ipa, ipb, ipc, ipd, cidr)                       \
+	wg_allowedips_insert_v##version(&t, ip##version(ipa, ipb, ipc, ipd), \
+					cidr, mem, &mutex)
+
+#define maybe_fail() do {                                               \
+		++i;                                                    \
+		if (!_s) {                                              \
+			pr_info("allowedips self-test %zu: FAIL\n", i); \
+			success = false;                                \
+		}                                                       \
+	} while (0)
+
+#define test(version, mem, ipa, ipb, ipc, ipd) do {                          \
+		bool _s = lookup(t.root##version, (version) == 4 ? 32 : 128, \
+				 ip##version(ipa, ipb, ipc, ipd)) == (mem);  \
+		maybe_fail();                                                \
+	} while (0)
+
+#define test_negative(version, mem, ipa, ipb, ipc, ipd) do {                 \
+		bool _s = lookup(t.root##version, (version) == 4 ? 32 : 128, \
+				 ip##version(ipa, ipb, ipc, ipd)) != (mem);  \
+		maybe_fail();                                                \
+	} while (0)
+
+#define test_boolean(cond) do {   \
+		bool _s = (cond); \
+		maybe_fail();     \
+	} while (0)
+
+bool __init wg_allowedips_selftest(void)
+{
+	bool found_a = false, found_b = false, found_c = false, found_d = false,
+	     found_e = false, found_other = false;
+	struct wg_peer *a = init_peer(), *b = init_peer(), *c = init_peer(),
+		       *d = init_peer(), *e = init_peer(), *f = init_peer(),
+		       *g = init_peer(), *h = init_peer();
+	struct allowedips_node *iter_node;
+	bool success = false;
+	struct allowedips t;
+	DEFINE_MUTEX(mutex);
+	struct in6_addr ip;
+	size_t i = 0, count = 0;
+	__be64 part;
+
+	mutex_init(&mutex);
+	mutex_lock(&mutex);
+	wg_allowedips_init(&t);
+
+	if (!a || !b || !c || !d || !e || !f || !g || !h) {
+		pr_err("allowedips self-test malloc: FAIL\n");
+		goto free;
+	}
+
+	insert(4, a, 192, 168, 4, 0, 24);
+	insert(4, b, 192, 168, 4, 4, 32);
+	insert(4, c, 192, 168, 0, 0, 16);
+	insert(4, d, 192, 95, 5, 64, 27);
+	/* replaces previous entry, and maskself is required */
+	insert(4, c, 192, 95, 5, 65, 27);
+	insert(6, d, 0x26075300, 0x60006b00, 0, 0xc05f0543, 128);
+	insert(6, c, 0x26075300, 0x60006b00, 0, 0, 64);
+	insert(4, e, 0, 0, 0, 0, 0);
+	insert(6, e, 0, 0, 0, 0, 0);
+	/* replaces previous entry */
+	insert(6, f, 0, 0, 0, 0, 0);
+	insert(6, g, 0x24046800, 0, 0, 0, 32);
+	/* maskself is required */
+	insert(6, h, 0x24046800, 0x40040800, 0xdeadbeef, 0xdeadbeef, 64);
+	insert(6, a, 0x24046800, 0x40040800, 0xdeadbeef, 0xdeadbeef, 128);
+	insert(6, c, 0x24446800, 0x40e40800, 0xdeaebeef, 0xdefbeef, 128);
+	insert(6, b, 0x24446800, 0xf0e40800, 0xeeaebeef, 0, 98);
+	insert(4, g, 64, 15, 112, 0, 20);
+	/* maskself is required */
+	insert(4, h, 64, 15, 123, 211, 25);
+	insert(4, a, 10, 0, 0, 0, 25);
+	insert(4, b, 10, 0, 0, 128, 25);
+	insert(4, a, 10, 1, 0, 0, 30);
+	insert(4, b, 10, 1, 0, 4, 30);
+	insert(4, c, 10, 1, 0, 8, 29);
+	insert(4, d, 10, 1, 0, 16, 29);
+
+	if (IS_ENABLED(DEBUG_PRINT_TRIE_GRAPHVIZ)) {
+		print_tree(t.root4, 32);
+		print_tree(t.root6, 128);
+	}
+
+	success = true;
+
+	test(4, a, 192, 168, 4, 20);
+	test(4, a, 192, 168, 4, 0);
+	test(4, b, 192, 168, 4, 4);
+	test(4, c, 192, 168, 200, 182);
+	test(4, c, 192, 95, 5, 68);
+	test(4, e, 192, 95, 5, 96);
+	test(6, d, 0x26075300, 0x60006b00, 0, 0xc05f0543);
+	test(6, c, 0x26075300, 0x60006b00, 0, 0xc02e01ee);
+	test(6, f, 0x26075300, 0x60006b01, 0, 0);
+	test(6, g, 0x24046800, 0x40040806, 0, 0x1006);
+	test(6, g, 0x24046800, 0x40040806, 0x1234, 0x5678);
+	test(6, f, 0x240467ff, 0x40040806, 0x1234, 0x5678);
+	test(6, f, 0x24046801, 0x40040806, 0x1234, 0x5678);
+	test(6, h, 0x24046800, 0x40040800, 0x1234, 0x5678);
+	test(6, h, 0x24046800, 0x40040800, 0, 0);
+	test(6, h, 0x24046800, 0x40040800, 0x10101010, 0x10101010);
+	test(6, a, 0x24046800, 0x40040800, 0xdeadbeef, 0xdeadbeef);
+	test(4, g, 64, 15, 116, 26);
+	test(4, g, 64, 15, 127, 3);
+	test(4, g, 64, 15, 123, 1);
+	test(4, h, 64, 15, 123, 128);
+	test(4, h, 64, 15, 123, 129);
+	test(4, a, 10, 0, 0, 52);
+	test(4, b, 10, 0, 0, 220);
+	test(4, a, 10, 1, 0, 2);
+	test(4, b, 10, 1, 0, 6);
+	test(4, c, 10, 1, 0, 10);
+	test(4, d, 10, 1, 0, 20);
+
+	insert(4, a, 1, 0, 0, 0, 32);
+	insert(4, a, 64, 0, 0, 0, 32);
+	insert(4, a, 128, 0, 0, 0, 32);
+	insert(4, a, 192, 0, 0, 0, 32);
+	insert(4, a, 255, 0, 0, 0, 32);
+	wg_allowedips_remove_by_peer(&t, a, &mutex);
+	test_negative(4, a, 1, 0, 0, 0);
+	test_negative(4, a, 64, 0, 0, 0);
+	test_negative(4, a, 128, 0, 0, 0);
+	test_negative(4, a, 192, 0, 0, 0);
+	test_negative(4, a, 255, 0, 0, 0);
+
+	wg_allowedips_free(&t, &mutex);
+	wg_allowedips_init(&t);
+	insert(4, a, 192, 168, 0, 0, 16);
+	insert(4, a, 192, 168, 0, 0, 24);
+	wg_allowedips_remove_by_peer(&t, a, &mutex);
+	test_negative(4, a, 192, 168, 0, 1);
+
+	/* These will hit the WARN_ON(len >= 128) in free_node if something
+	 * goes wrong.
+	 */
+	for (i = 0; i < 128; ++i) {
+		part = cpu_to_be64(~(1LLU << (i % 64)));
+		memset(&ip, 0xff, 16);
+		memcpy((u8 *)&ip + (i < 64) * 8, &part, 8);
+		wg_allowedips_insert_v6(&t, &ip, 128, a, &mutex);
+	}
+
+	wg_allowedips_free(&t, &mutex);
+
+	wg_allowedips_init(&t);
+	insert(4, a, 192, 95, 5, 93, 27);
+	insert(6, a, 0x26075300, 0x60006b00, 0, 0xc05f0543, 128);
+	insert(4, a, 10, 1, 0, 20, 29);
+	insert(6, a, 0x26075300, 0x6d8a6bf8, 0xdab1f1df, 0xc05f1523, 83);
+	insert(6, a, 0x26075300, 0x6d8a6bf8, 0xdab1f1df, 0xc05f1523, 21);
+	list_for_each_entry(iter_node, &a->allowedips_list, peer_list) {
+		u8 cidr, ip[16] __aligned(__alignof(u64));
+		int family = wg_allowedips_read_node(iter_node, ip, &cidr);
+
+		count++;
+
+		if (cidr == 27 && family == AF_INET &&
+		    !memcmp(ip, ip4(192, 95, 5, 64), sizeof(struct in_addr)))
+			found_a = true;
+		else if (cidr == 128 && family == AF_INET6 &&
+			 !memcmp(ip, ip6(0x26075300, 0x60006b00, 0, 0xc05f0543),
+				 sizeof(struct in6_addr)))
+			found_b = true;
+		else if (cidr == 29 && family == AF_INET &&
+			 !memcmp(ip, ip4(10, 1, 0, 16), sizeof(struct in_addr)))
+			found_c = true;
+		else if (cidr == 83 && family == AF_INET6 &&
+			 !memcmp(ip, ip6(0x26075300, 0x6d8a6bf8, 0xdab1e000, 0),
+				 sizeof(struct in6_addr)))
+			found_d = true;
+		else if (cidr == 21 && family == AF_INET6 &&
+			 !memcmp(ip, ip6(0x26075000, 0, 0, 0),
+				 sizeof(struct in6_addr)))
+			found_e = true;
+		else
+			found_other = true;
+	}
+	test_boolean(count == 5);
+	test_boolean(found_a);
+	test_boolean(found_b);
+	test_boolean(found_c);
+	test_boolean(found_d);
+	test_boolean(found_e);
+	test_boolean(!found_other);
+
+	if (IS_ENABLED(DEBUG_RANDOM_TRIE) && success)
+		success = randomized_test();
+
+	if (success)
+		pr_info("allowedips self-tests: pass\n");
+
+free:
+	wg_allowedips_free(&t, &mutex);
+	kfree(a);
+	kfree(b);
+	kfree(c);
+	kfree(d);
+	kfree(e);
+	kfree(f);
+	kfree(g);
+	kfree(h);
+	mutex_unlock(&mutex);
+
+	return success;
+}
+
+#undef test_negative
+#undef test
+#undef remove
+#undef insert
+#undef init_peer
+
+#endif