![Jason A. Donenfeld](/assets/img/avatar_default.png)
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>
84 lines
2.1 KiB
C
84 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
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*/
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#ifndef _WG_PEER_H
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#define _WG_PEER_H
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#include "device.h"
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#include "noise.h"
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#include "cookie.h"
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#include <linux/types.h>
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#include <linux/netfilter.h>
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#include <linux/spinlock.h>
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#include <linux/kref.h>
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#include <net/dst_cache.h>
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struct wg_device;
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struct endpoint {
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union {
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struct sockaddr addr;
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struct sockaddr_in addr4;
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struct sockaddr_in6 addr6;
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};
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union {
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struct {
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struct in_addr src4;
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/* Essentially the same as addr6->scope_id */
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int src_if4;
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};
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struct in6_addr src6;
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};
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};
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struct wg_peer {
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struct wg_device *device;
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struct crypt_queue tx_queue, rx_queue;
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struct sk_buff_head staged_packet_queue;
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int serial_work_cpu;
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struct noise_keypairs keypairs;
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struct endpoint endpoint;
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struct dst_cache endpoint_cache;
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rwlock_t endpoint_lock;
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struct noise_handshake handshake;
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atomic64_t last_sent_handshake;
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struct work_struct transmit_handshake_work, clear_peer_work;
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struct cookie latest_cookie;
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struct hlist_node pubkey_hash;
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u64 rx_bytes, tx_bytes;
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struct timer_list timer_retransmit_handshake, timer_send_keepalive;
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struct timer_list timer_new_handshake, timer_zero_key_material;
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struct timer_list timer_persistent_keepalive;
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unsigned int timer_handshake_attempts;
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u16 persistent_keepalive_interval;
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bool timer_need_another_keepalive;
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bool sent_lastminute_handshake;
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struct timespec64 walltime_last_handshake;
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struct kref refcount;
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struct rcu_head rcu;
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struct list_head peer_list;
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struct list_head allowedips_list;
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u64 internal_id;
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struct napi_struct napi;
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bool is_dead;
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};
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struct wg_peer *wg_peer_create(struct wg_device *wg,
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const u8 public_key[NOISE_PUBLIC_KEY_LEN],
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const u8 preshared_key[NOISE_SYMMETRIC_KEY_LEN]);
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struct wg_peer *__must_check wg_peer_get_maybe_zero(struct wg_peer *peer);
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static inline struct wg_peer *wg_peer_get(struct wg_peer *peer)
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{
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kref_get(&peer->refcount);
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return peer;
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}
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void wg_peer_put(struct wg_peer *peer);
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void wg_peer_remove(struct wg_peer *peer);
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void wg_peer_remove_all(struct wg_device *wg);
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#endif /* _WG_PEER_H */
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