1 files changed, 352 insertions, 0 deletions
diff --git a/src/device.c b/src/device.c
new file mode 100644
index 0000000..4076e58
--- /dev/null
+++ b/src/device.c
@@ -0,0 +1,352 @@
+/* Copyright 2015-2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
+
+#include "wireguard.h"
+#include "packets.h"
+#include "socket.h"
+#include "timers.h"
+#include "device.h"
+#include "config.h"
+#include "peer.h"
+#include "uapi.h"
+#include "messages.h"
+#include <linux/module.h>
+#include <linux/rtnetlink.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/icmp.h>
+#include <net/icmp.h>
+#include <net/rtnetlink.h>
+#include <net/ip_tunnels.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_nat_core.h>
+
+#define MAX_QUEUED_PACKETS 1024
+
+static int init(struct net_device *dev)
+{
+	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
+	if (!dev->tstats)
+		return -ENOMEM;
+	return 0;
+}
+static void uninit(struct net_device *dev)
+{
+	free_percpu(dev->tstats);
+}
+
+static int open_peer(struct wireguard_peer *peer, void *data)
+{
+	socket_set_peer_dst(peer);
+	timers_init_peer(peer);
+	packet_send_queue(peer);
+	return 0;
+}
+
+static int open(struct net_device *dev)
+{
+	struct wireguard_device *wg = netdev_priv(dev);
+	int rc = socket_init(wg);
+	if (rc < 0)
+		return rc;
+	peer_for_each(wg, open_peer, NULL);
+	return 0;
+}
+
+static int stop_peer(struct wireguard_peer *peer, void *data)
+{
+	timers_uninit_peer_wait(peer);
+	noise_handshake_clear(&peer->handshake);
+	noise_keypairs_clear(&peer->keypairs);
+	return 0;
+}
+
+static int stop(struct net_device *dev)
+{
+	struct wireguard_device *wg = netdev_priv(dev);
+	peer_for_each(wg, stop_peer, NULL);
+	skb_queue_purge(&wg->incoming_handshakes);
+	socket_uninit(wg);
+	return 0;
+}
+
+static void skb_unsendable(struct sk_buff *skb, struct net_device *dev)
+{
+	/* This conntrack stuff is because the rate limiting needs to be applied
+	 * to the original src IP, so we have to restore saddr in the IP header. */
+	struct nf_conn *ct = NULL;
+#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
+	enum ip_conntrack_info ctinfo;
+	ct = nf_ct_get(skb, &ctinfo);
+#endif
+	++dev->stats.tx_errors;
+
+	if (skb->len < sizeof(struct iphdr))
+		goto free;
+
+	if (ip_hdr(skb)->version == 4) {
+		if (ct)
+			ip_hdr(skb)->saddr = ct->tuplehash[0].tuple.src.u3.ip;
+		icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
+	} else if (ip_hdr(skb)->version == 6) {
+		if (ct)
+			ipv6_hdr(skb)->saddr = ct->tuplehash[0].tuple.src.u3.in6;
+		icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
+	}
+free:
+	kfree_skb(skb);
+}
+
+static netdev_tx_t xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct wireguard_device *wg = netdev_priv(dev);
+	struct wireguard_peer *peer;
+	int ret;
+
+	if (unlikely(dev_recursion_level() > 4)) {
+		net_dbg_ratelimited("Routing loop detected\n");
+		skb_unsendable(skb, dev);
+		return -ELOOP;
+	}
+
+	dev->trans_start = jiffies;
+
+	peer = routing_table_lookup_dst(&wg->peer_routing_table, skb);
+	if (unlikely(!peer)) {
+		skb_unsendable(skb, dev);
+		return -ENOKEY;
+	}
+
+	read_lock_bh(&peer->endpoint_lock);
+	ret = unlikely(peer->endpoint_addr.ss_family != AF_INET && peer->endpoint_addr.ss_family != AF_INET6);
+	read_unlock_bh(&peer->endpoint_lock);
+	if (ret) {
+		net_dbg_ratelimited("No valid endpoint has been configured or discovered for device\n");
+		peer_put(peer);
+		skb_unsendable(skb, dev);
+		return -EHOSTUNREACH;
+	}
+
+	/* If the queue is getting too big, we start removing the oldest packets until it's small again.
+	 * We do this before adding the new packet, so we don't remove GSO segments that are in excess. */
+	while (skb_queue_len(&peer->tx_packet_queue) > MAX_QUEUED_PACKETS)
+		dev_kfree_skb(skb_dequeue(&peer->tx_packet_queue));
+
+	if (!skb_is_gso(skb))
+		skb->next = NULL;
+	else {
+		struct sk_buff *segs = skb_gso_segment(skb, 0);
+		if (unlikely(IS_ERR(segs))) {
+			skb_unsendable(skb, dev);
+			peer_put(peer);
+			return PTR_ERR(segs);
+		}
+		dev_kfree_skb(skb);
+		skb = segs;
+	}
+	while (skb) {
+		struct sk_buff *next = skb->next;
+		skb->next = skb->prev = NULL;
+
+		skb = skb_share_check(skb, GFP_ATOMIC);
+		if (unlikely(!skb))
+			continue;
+
+		/* We only need to keep the original dst around for icmp,
+		 * so at this point we're in a position to drop it. */
+		skb_dst_drop(skb);
+
+		skb_queue_tail(&peer->tx_packet_queue, skb);
+		skb = next;
+	}
+
+	ret = packet_send_queue(peer);
+	peer_put(peer);
+	return ret;
+}
+
+
+static int ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+	struct wireguard_device *wg = netdev_priv(dev);
+
+	if (!ns_capable(dev_net(dev)->user_ns, CAP_NET_ADMIN))
+		return -EPERM;
+
+	switch (cmd) {
+	case WG_GET_DEVICE:
+		return config_get_device(wg, ifr->ifr_ifru.ifru_data);
+	case WG_SET_DEVICE:
+		return config_set_device(wg, ifr->ifr_ifru.ifru_data);
+	}
+	return -EINVAL;
+}
+
+static const struct net_device_ops netdev_ops = {
+	.ndo_init		= init,
+	.ndo_uninit		= uninit,
+	.ndo_open		= open,
+	.ndo_stop		= stop,
+	.ndo_start_xmit		= xmit,
+	.ndo_get_stats64	= ip_tunnel_get_stats64,
+	.ndo_do_ioctl		= ioctl
+};
+
+static void destruct(struct net_device *dev)
+{
+	struct wireguard_device *wg = netdev_priv(dev);
+
+	mutex_lock(&wg->device_update_lock);
+	peer_remove_all(wg);
+	wg->incoming_port = 0;
+	destroy_workqueue(wg->workqueue);
+#ifdef CONFIG_WIREGUARD_PARALLEL
+	destroy_workqueue(wg->parallelqueue);
+	padata_free(wg->parallel_send);
+	padata_free(wg->parallel_receive);
+#endif
+	routing_table_free(&wg->peer_routing_table);
+	memzero_explicit(&wg->static_identity, sizeof(struct noise_static_identity));
+	skb_queue_purge(&wg->incoming_handshakes);
+	socket_uninit(wg);
+	cookie_checker_uninit(&wg->cookie_checker);
+	mutex_unlock(&wg->device_update_lock);
+
+	put_net(wg->creating_net);
+
+	pr_debug("Device %s has been deleted\n", dev->name);
+	free_netdev(dev);
+}
+
+#define WG_FEATURES (NETIF_F_HW_CSUM | NETIF_F_RXCSUM | NETIF_F_SG | NETIF_F_GSO | NETIF_F_GSO_SOFTWARE | NETIF_F_HIGHDMA)
+
+static void setup(struct net_device *dev)
+{
+	struct wireguard_device *wg = netdev_priv(dev);
+
+	dev->netdev_ops = &netdev_ops;
+	dev->destructor = destruct;
+	dev->hard_header_len = 0;
+	dev->addr_len = 0;
+	dev->needed_headroom = DATA_PACKET_HEAD_ROOM;
+	dev->needed_tailroom = noise_encrypted_len(MESSAGE_PADDING_MULTIPLE);
+	dev->type = ARPHRD_NONE;
+	dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0)
+	dev->flags |= IFF_NO_QUEUE;
+#else
+	dev->tx_queue_len = 0;
+#endif
+	dev->features |= NETIF_F_LLTX;
+	dev->features |= WG_FEATURES;
+	dev->hw_features |= WG_FEATURES;
+	dev->hw_enc_features |= WG_FEATURES;
+	dev->mtu = ETH_DATA_LEN - MESSAGE_MINIMUM_LENGTH - sizeof(struct udphdr) - max(sizeof(struct ipv6hdr), sizeof(struct iphdr));
+
+	/* We need to keep the dst around in case of icmp replies. */
+	netif_keep_dst(dev);
+
+	memset(wg, 0, sizeof(struct wireguard_device));
+}
+
+static int newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[], struct nlattr *data[])
+{
+	int ret = 0;
+	struct wireguard_device *wg = netdev_priv(dev);
+
+	wg->creating_net = get_net(src_net);
+	init_rwsem(&wg->static_identity.lock);
+	mutex_init(&wg->socket_update_lock);
+	mutex_init(&wg->device_update_lock);
+	skb_queue_head_init(&wg->incoming_handshakes);
+	INIT_WORK(&wg->incoming_handshakes_work, packet_process_queued_handshake_packets);
+	pubkey_hashtable_init(&wg->peer_hashtable);
+	index_hashtable_init(&wg->index_hashtable);
+	routing_table_init(&wg->peer_routing_table);
+	INIT_LIST_HEAD(&wg->peer_list);
+
+	wg->workqueue = alloc_workqueue(KBUILD_MODNAME "-%s", WQ_UNBOUND | WQ_FREEZABLE, 0, dev->name);
+	if (!wg->workqueue) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+#ifdef CONFIG_WIREGUARD_PARALLEL
+	wg->parallelqueue = alloc_workqueue(KBUILD_MODNAME "-crypt-%s", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1, dev->name);
+	if (!wg->parallelqueue) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	wg->parallel_send = padata_alloc_possible(wg->parallelqueue);
+	if (!wg->parallel_send) {
+		ret = -ENOMEM;
+		goto err;
+	}
+	padata_start(wg->parallel_send);
+
+	wg->parallel_receive = padata_alloc_possible(wg->parallelqueue);
+	if (!wg->parallel_receive) {
+		ret = -ENOMEM;
+		goto err;
+	}
+	padata_start(wg->parallel_receive);
+#endif
+
+	ret = cookie_checker_init(&wg->cookie_checker, wg);
+	if (ret < 0)
+		goto err;
+
+	ret = register_netdevice(dev);
+	if (ret < 0)
+		goto err;
+
+	pr_debug("Device %s has been created\n", dev->name);
+
+	return 0;
+
+err:
+	put_net(src_net);
+	if (wg->workqueue)
+		destroy_workqueue(wg->workqueue);
+#ifdef CONFIG_WIREGUARD_PARALLEL
+	if (wg->parallelqueue)
+		destroy_workqueue(wg->parallelqueue);
+	if (wg->parallel_send)
+		padata_free(wg->parallel_send);
+	if (wg->parallel_receive)
+		padata_free(wg->parallel_receive);
+#endif
+	if (wg->cookie_checker.device)
+		cookie_checker_uninit(&wg->cookie_checker);
+	return ret;
+}
+
+static void dellink(struct net_device *dev, struct list_head *head)
+{
+	unregister_netdevice_queue(dev, head);
+}
+
+static struct rtnl_link_ops link_ops __read_mostly = {
+	.kind			= KBUILD_MODNAME,
+	.priv_size		= sizeof(struct wireguard_device),
+	.setup			= setup,
+	.newlink		= newlink,
+	.dellink		= dellink
+};
+
+int device_init(void)
+{
+	int ret = rtnl_link_register(&link_ops);
+	if (ret < 0) {
+		pr_err("Cannot register link_ops\n");
+		return ret;
+	}
+	return ret;
+}
+
+void device_uninit(void)
+{
+	rtnl_link_unregister(&link_ops);
+	rcu_barrier();
+}