path: root/drivers/net/wireguard/device.h
diff options
authorJason A. Donenfeld <Jason@zx2c4.com>2019-12-09 00:27:34 +0100
committerDavid S. Miller <davem@davemloft.net>2019-12-08 17:48:42 -0800
commite7096c131e5161fa3b8e52a650d7719d2857adfd (patch)
tree269266506f365dd23e8ccf9a16dcfc2d8af1b0c5 /drivers/net/wireguard/device.h
parentLinux 5.5-rc1 (diff)
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>
Diffstat (limited to 'drivers/net/wireguard/device.h')
1 files changed, 73 insertions, 0 deletions
diff --git a/drivers/net/wireguard/device.h b/drivers/net/wireguard/device.h
new file mode 100644
index 000000000000..c91f3051c5c7
--- /dev/null
+++ b/drivers/net/wireguard/device.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+#ifndef _WG_DEVICE_H
+#define _WG_DEVICE_H
+#include "noise.h"
+#include "allowedips.h"
+#include "peerlookup.h"
+#include "cookie.h"
+#include <linux/types.h>
+#include <linux/netdevice.h>
+#include <linux/workqueue.h>
+#include <linux/mutex.h>
+#include <linux/net.h>
+#include <linux/ptr_ring.h>
+struct wg_device;
+struct multicore_worker {
+ void *ptr;
+ struct work_struct work;
+struct crypt_queue {
+ struct ptr_ring ring;
+ union {
+ struct {
+ struct multicore_worker __percpu *worker;
+ int last_cpu;
+ };
+ struct work_struct work;
+ };
+struct wg_device {
+ struct net_device *dev;
+ struct crypt_queue encrypt_queue, decrypt_queue;
+ struct sock __rcu *sock4, *sock6;
+ struct net *creating_net;
+ struct noise_static_identity static_identity;
+ struct workqueue_struct *handshake_receive_wq, *handshake_send_wq;
+ struct workqueue_struct *packet_crypt_wq;
+ struct sk_buff_head incoming_handshakes;
+ int incoming_handshake_cpu;
+ struct multicore_worker __percpu *incoming_handshakes_worker;
+ struct cookie_checker cookie_checker;
+ struct pubkey_hashtable *peer_hashtable;
+ struct index_hashtable *index_hashtable;
+ struct allowedips peer_allowedips;
+ struct mutex device_update_lock, socket_update_lock;
+ struct list_head device_list, peer_list;
+ unsigned int num_peers, device_update_gen;
+ u32 fwmark;
+ u16 incoming_port;
+ bool have_creating_net_ref;
+int wg_device_init(void);
+void wg_device_uninit(void);
+/* Later after the dust settles, this can be moved into include/linux/skbuff.h,
+ * where virtually all code that deals with GSO segs can benefit, around ~30
+ * drivers as of writing.
+ */
+#define skb_list_walk_safe(first, skb, next) \
+ for (skb = first, next = skb->next; skb; \
+ skb = next, next = skb ? skb->next : NULL)
+#endif /* _WG_DEVICE_H */