// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015-2019 Jason A. Donenfeld <[email protected]>. All Rights Reserved.
*/
#include "device.h"
#include "peer.h"
#include "socket.h"
#include "queueing.h"
#include "messages.h"
#include <linux/ctype.h>
#include <linux/net.h>
#include <linux/if_vlan.h>
#include <linux/if_ether.h>
#include <linux/inetdevice.h>
#include <net/udp_tunnel.h>
#include <net/ipv6.h>
static int send4(struct wg_device *wg, struct sk_buff *skb,
struct endpoint *endpoint, u8 ds, struct dst_cache *cache)
{
struct flowi4 fl = {
.saddr = endpoint->src4.s_addr,
.daddr = endpoint->addr4.sin_addr.s_addr,
.fl4_dport = endpoint->addr4.sin_port,
.flowi4_mark = wg->fwmark,
.flowi4_proto = IPPROTO_UDP
};
struct rtable *rt = NULL;
struct sock *sock;
int ret = 0;
skb_mark_not_on_list(skb);
skb->dev = wg->dev;
skb->mark = wg->fwmark;
rcu_read_lock_bh();
sock = rcu_dereference_bh(wg->sock4);
if (unlikely(!sock)) {
ret = -ENONET;
goto err;
}
fl.fl4_sport = inet_sk(sock)->inet_sport;
if (cache)
rt = dst_cache_get_ip4(cache, &fl.saddr);
if (!rt) {
security_sk_classify_flow(sock, flowi4_to_flowi_common(&fl));
if (unlikely(!inet_confirm_addr(sock_net(sock), NULL, 0,
fl.saddr, RT_SCOPE_HOST))) {
endpoint->src4.s_addr = 0;
endpoint->src_if4 = 0;
fl.saddr = 0;
if (cache)
dst_cache_reset(cache);
}
rt = ip_route_output_flow(sock_net(sock), &fl, sock);
if (unlikely(endpoint->src_if4 && ((IS_ERR(rt) &&
PTR_ERR(rt) == -EINVAL) || (!IS_ERR(rt) &&
rt->dst.dev->ifindex != endpoint->src_if4)))) {
endpoint->src4.s_addr = 0;
endpoint->src_if4 = 0;
fl.saddr = 0;
if (cache)
dst_cache_reset(cache);
if (!IS_ERR(rt))
ip_rt_put(rt);
rt = ip_route_output_flow(sock_net(sock), &fl, sock);
}
if (IS_ERR(rt)) {
ret = PTR_ERR(rt);
net_dbg_ratelimited("%s: No route to %pISpfsc, error %d\n",
wg->dev->name, &endpoint->addr, ret);
goto err;
}
if (cache)
dst_cache_set_ip4(cache, &rt->dst, fl.saddr);
}
skb->ignore_df = 1;
udp_tunnel_xmit_skb(rt, sock, skb, fl.saddr, fl.daddr, ds,
ip4_dst_hoplimit(&rt->dst), 0, fl.fl4_sport,
fl.fl4_dport, false, false);
goto out;
err:
kfree_skb(skb);
out:
rcu_read_unlock_bh();
return ret;
}
static int send6(struct wg_device *wg, struct sk_buff *skb,
struct endpoint *endpoint, u8 ds, struct dst_cache *cache)
{
#if IS_ENABLED(CONFIG_IPV6)
struct flowi6 fl = {
.saddr = endpoint->src6,
.daddr = endpoint->addr6.sin6_addr,
.fl6_dport = endpoint->addr6.sin6_port,
.flowi6_mark = wg->fwmark,
.flowi6_oif = endpoint->addr6.sin6_scope_id,
.flowi6_proto = IPPROTO_UDP
/* TODO: addr->sin6_flowinfo */
};
struct dst_entry *dst = NULL;
struct sock *sock;
int ret = 0;
skb_mark_not_on_list(skb);
skb->dev = wg->dev;
skb->mark = wg->fwmark;
rcu_read_lock_bh();
sock = rcu_dereference_bh(wg->sock6);
if (unlikely(!sock)) {
ret = -ENONET;
goto err;
}
fl.fl6_sport = inet_sk(sock)->inet_sport;
if (cache)
dst = dst_cache_get_ip6(cache, &fl.saddr);
if (!dst) {
security_sk_classify_flow(sock, flowi6_to_flowi_common(&fl));
if (unlikely(!ipv6_addr_any(&fl.saddr) &&
!ipv6_chk_addr(sock_net(sock), &fl.saddr, NULL, 0))) {
endpoint->src6 = fl.saddr = in6addr_any;
if (cache)
dst_cache_reset(cache);
}
dst = ipv6_stub->ipv6_dst_lookup_flow(sock_net(sock), sock, &fl,
NULL);
if (IS_ERR(dst)) {
ret = PTR_ERR(dst);
net_dbg_ratelimited("%s: No route to %pISpfsc, error %d\n",
wg->dev->name, &endpoint->addr, ret);
goto err;
}
if (cache)
dst_cache_set_ip6(cache, dst, &fl.saddr);
}
skb->ignore_df = 1;
udp_tunnel6_xmit_skb(dst, sock, skb, skb->dev, &fl.saddr, &fl.daddr, ds,
ip6_dst_hoplimit(dst), 0, fl.fl6_sport,
fl.fl6_dport, false);
goto out;
err:
kfree_skb(skb);
out:
rcu_read_unlock_bh();
return ret;
#else
kfree_skb(skb);
return -EAFNOSUPPORT;
#endif
}
int wg_socket_send_skb_to_peer(struct wg_peer *peer, struct sk_buff *skb, u8 ds)
{
size_t skb_len = skb->len;
int ret = -EAFNOSUPPORT;
read_lock_bh(&peer->endpoint_lock);
if (peer->endpoint.addr.sa_family == AF_INET)
ret = send4(peer->device, skb, &peer->endpoint, ds,
&peer->endpoint_cache);
else if (peer->endpoint.addr.sa_family == AF_INET6)
ret = send6(peer->device, skb, &peer->endpoint, ds,
&peer->endpoint_cache);
else
dev_kfree_skb(skb);
if (likely(!ret))
peer->tx_bytes += skb_len;
read_unlock_bh(&peer->endpoint_lock);
return ret;
}
int wg_socket_send_buffer_to_peer(struct wg_peer *peer, void *buffer,
size_t len, u8 ds)
{
struct sk_buff *skb = alloc_skb(len + SKB_HEADER_LEN, GFP_ATOMIC);
if (unlikely(!skb))
return -ENOMEM;
skb_reserve(skb, SKB_HEADER_LEN);
skb_set_inner_network_header(skb, 0);
skb_put_data(skb, buffer, len);
return wg_socket_send_skb_to_peer(peer, skb, ds);
}
int wg_socket_send_buffer_as_reply_to_skb(struct wg_device *wg,
struct sk_buff *in_skb, void *buffer,
size_t len)
{
int ret = 0;
struct sk_buff *skb;
struct endpoint endpoint;
if (unlikely(!in_skb))
return -EINVAL;
ret = wg_socket_endpoint_from_skb(&endpoint, in_skb);
if (unlikely(ret < 0))
return ret;
skb = alloc_skb(len + SKB_HEADER_LEN, GFP_ATOMIC);
if (unlikely(!skb))
return -ENOMEM;
skb_reserve(skb, SKB_HEADER_LEN);
skb_set_inner_network_header(skb, 0);
skb_put_data(skb, buffer, len);
if (endpoint.addr.sa_family == AF_INET)
ret = send4(wg, skb, &endpoint, 0, NULL);
else if (endpoint.addr.sa_family == AF_INET6)
ret = send6(wg, skb, &endpoint, 0, NULL);
/* No other possibilities if the endpoint is valid, which it is,
* as we checked above.
*/
return ret;
}
int wg_socket_endpoint_from_skb(struct endpoint *endpoint,
const struct sk_buff *skb)
{
memset(endpoint, 0, sizeof(*endpoint));
if (skb->protocol == htons(ETH_P_IP)) {
endpoint->addr4.sin_family = AF_INET;
endpoint->addr4.sin_port = udp_hdr(skb)->source;
endpoint->addr4.sin_addr.s_addr = ip_hdr(skb)->saddr;
endpoint->src4.s_addr = ip_hdr(skb)->daddr;
endpoint->src_if4 = skb->skb_iif;
} else if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) {
endpoint->addr6.sin6_family = AF_INET6;
endpoint->addr6.sin6_port = udp_hdr(skb)->source;
endpoint->addr6.sin6_addr = ipv6_hdr(skb)->saddr;
endpoint->addr6.sin6_scope_id = ipv6_iface_scope_id(
&ipv6_hdr(skb)->saddr, skb->skb_iif);
endpoint->src6 = ipv6_hdr(skb)->daddr;
} else {
return -EINVAL;
}
return 0;
}
static bool endpoint_eq(const struct endpoint *a, const struct endpoint *b)
{
return (a->addr.sa_family == AF_INET && b->addr.sa_family == AF_INET &&
a->addr4.sin_port == b->addr4.sin_port &&
a->addr4.sin_addr.s_addr == b->addr4.sin_addr.s_addr &&
a->src4.s_addr == b->src4.s_addr && a->src_if4 == b->src_if4) ||
(a->addr.sa_family == AF_INET6 &&
b->addr.sa_family == AF_INET6 &&
a->addr6.sin6_port == b->addr6.sin6_port &&
ipv6_addr_equal(&a->addr6.sin6_addr, &b->addr6.sin6_addr) &&
a->addr6.sin6_scope_id == b->addr6.sin6_scope_id &&
ipv6_addr_equal(&a->src6, &b->src6)) ||
unlikely(!a->addr.sa_family && !b->addr.sa_family);
}
void wg_socket_set_peer_endpoint(struct wg_peer *peer,
const struct endpoint *endpoint)
{
/* First we check unlocked, in order to optimize, since it's pretty rare
* that an endpoint will change. If we happen to be mid-write, and two
* CPUs wind up writing the same thing or something slightly different,
* it doesn't really matter much either.
*/
if (endpoint_eq(endpoint, &peer->endpoint))
return;
write_lock_bh(&peer->endpoint_lock);
if (endpoint->addr.sa_family == AF_INET) {
peer->endpoint.addr4 = endpoint->addr4;
peer->endpoint.src4 = endpoint->src4;
peer->endpoint.src_if4 = endpoint->src_if4;
} else if (IS_ENABLED(CONFIG_IPV6) && endpoint->addr.sa_family == AF_INET6) {
peer->endpoint.addr6 = endpoint->addr6;
peer->endpoint.src6 = endpoint->src6;
} else {
goto out;
}
dst_cache_reset(&peer->endpoint_cache);
out:
write_unlock_bh(&peer->endpoint_lock);
}
void wg_socket_set_peer_endpoint_from_skb(struct wg_peer *peer,
const struct sk_buff *skb)
{
struct endpoint endpoint;
if (!wg_socket_endpoint_from_skb(&endpoint, skb))
wg_socket_set_peer_endpoint(peer, &endpoint);
}
void wg_socket_clear_peer_endpoint_src(struct wg_peer *peer)
{
write_lock_bh(&peer->endpoint_lock);
memset(&peer->endpoint.src6, 0, sizeof(peer->endpoint.src6));
dst_cache_reset_now(&peer->endpoint_cache);
write_unlock_bh(&peer->endpoint_lock);
}
static int wg_receive(struct sock *sk, struct sk_buff *skb)
{
struct wg_device *wg;
if (unlikely(!sk))
goto err;
wg = sk->sk_user_data;
if (unlikely(!wg))
goto err;
skb_mark_not_on_list(skb);
wg_packet_receive(wg, skb);
return 0;
err:
kfree_skb(skb);
return 0;
}
static void sock_free(struct sock *sock)
{
if (unlikely(!sock))
return;
sk_clear_memalloc(sock);
udp_tunnel_sock_release(sock->sk_socket);
}
static void set_sock_opts(struct socket *sock)
{
sock->sk->sk_allocation = GFP_ATOMIC;
sock->sk->sk_sndbuf = INT_MAX;
sk_set_memalloc(sock->sk);
}
int wg_socket_init(struct wg_device *wg, u16 port)
{
struct net *net;
int ret;
struct udp_tunnel_sock_cfg cfg = {
.sk_user_data = wg,
.encap_type = 1,
.encap_rcv = wg_receive
};
struct socket *new4 = NULL, *new6 = NULL;
struct udp_port_cfg port4 = {
.family = AF_INET,
.local_ip.s_addr = htonl(INADDR_ANY),
.local_udp_port = htons(port),
.use_udp_checksums = true
};
#if IS_ENABLED(CONFIG_IPV6)
int retries = 0;
struct udp_port_cfg port6 = {
.family = AF_INET6,
.local_ip6 = IN6ADDR_ANY_INIT,
.use_udp6_tx_checksums = true,
.use_udp6_rx_checksums = true,
.ipv6_v6only = true
};
#endif
rcu_read_lock();
net = rcu_dereference(wg->creating_net);
net = net ? maybe_get_net(net) : NULL;
rcu_read_unlock();
if (unlikely(!net))
return -ENONET;
#if IS_ENABLED(CONFIG_IPV6)
retry:
#endif
ret = udp_sock_create(net, &port4, &new4);
if (ret < 0) {
pr_err("%s: Could not create IPv4 socket\n", wg->dev->name);
goto out;
}
set_sock_opts(new4);
setup_udp_tunnel_sock(net, new4, &cfg);
#if IS_ENABLED(CONFIG_IPV6)
if (ipv6_mod_enabled()) {
port6.local_udp_port = inet_sk(new4->sk)->inet_sport;
ret = udp_sock_create(net, &port6, &new6);
if (ret < 0) {
udp_tunnel_sock_release(new4);
if (ret == -EADDRINUSE && !port && retries++ < 100)
goto retry;
pr_err("%s: Could not create IPv6 socket\n",
wg->dev->name);
goto out;
}
set_sock_opts(new6);
setup_udp_tunnel_sock(net, new6, &cfg);
}
#endif
wg_socket_reinit(wg, new4->sk, new6 ? new6->sk : NULL);
ret = 0;
out:
put_net(net);
return ret;
}
void wg_socket_reinit(struct wg_device *wg, struct sock *new4,
struct sock *new6)
{
struct sock *old4, *old6;
mutex_lock(&wg->socket_update_lock);
old4 = rcu_dereference_protected(wg->sock4,
lockdep_is_held(&wg->socket_update_lock));
old6 = rcu_dereference_protected(wg->sock6,
lockdep_is_held(&wg->socket_update_lock));
rcu_assign_pointer(wg->sock4, new4);
rcu_assign_pointer(wg->sock6, new6);
if (new4)
wg->incoming_port = ntohs(inet_sk(new4)->inet_sport);
mutex_unlock(&wg->socket_update_lock);
synchronize_net();
sock_free(old4);
sock_free(old6);
}
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