438 lines
11 KiB
C
438 lines
11 KiB
C
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// 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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#include "device.h"
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#include "peer.h"
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#include "socket.h"
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#include "queueing.h"
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#include "messages.h"
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#include <linux/ctype.h>
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#include <linux/net.h>
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#include <linux/if_vlan.h>
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#include <linux/if_ether.h>
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#include <linux/inetdevice.h>
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#include <net/udp_tunnel.h>
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#include <net/ipv6.h>
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static int send4(struct wg_device *wg, struct sk_buff *skb,
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struct endpoint *endpoint, u8 ds, struct dst_cache *cache)
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{
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struct flowi4 fl = {
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.saddr = endpoint->src4.s_addr,
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.daddr = endpoint->addr4.sin_addr.s_addr,
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.fl4_dport = endpoint->addr4.sin_port,
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.flowi4_mark = wg->fwmark,
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.flowi4_proto = IPPROTO_UDP
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};
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struct rtable *rt = NULL;
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struct sock *sock;
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int ret = 0;
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skb_mark_not_on_list(skb);
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skb->dev = wg->dev;
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skb->mark = wg->fwmark;
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rcu_read_lock_bh();
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sock = rcu_dereference_bh(wg->sock4);
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if (unlikely(!sock)) {
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ret = -ENONET;
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goto err;
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}
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fl.fl4_sport = inet_sk(sock)->inet_sport;
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if (cache)
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rt = dst_cache_get_ip4(cache, &fl.saddr);
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if (!rt) {
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security_sk_classify_flow(sock, flowi4_to_flowi_common(&fl));
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if (unlikely(!inet_confirm_addr(sock_net(sock), NULL, 0,
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fl.saddr, RT_SCOPE_HOST))) {
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endpoint->src4.s_addr = 0;
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endpoint->src_if4 = 0;
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fl.saddr = 0;
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if (cache)
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dst_cache_reset(cache);
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}
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rt = ip_route_output_flow(sock_net(sock), &fl, sock);
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if (unlikely(endpoint->src_if4 && ((IS_ERR(rt) &&
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PTR_ERR(rt) == -EINVAL) || (!IS_ERR(rt) &&
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rt->dst.dev->ifindex != endpoint->src_if4)))) {
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endpoint->src4.s_addr = 0;
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endpoint->src_if4 = 0;
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fl.saddr = 0;
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if (cache)
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dst_cache_reset(cache);
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if (!IS_ERR(rt))
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ip_rt_put(rt);
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rt = ip_route_output_flow(sock_net(sock), &fl, sock);
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}
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if (IS_ERR(rt)) {
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ret = PTR_ERR(rt);
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net_dbg_ratelimited("%s: No route to %pISpfsc, error %d\n",
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wg->dev->name, &endpoint->addr, ret);
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goto err;
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}
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if (cache)
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dst_cache_set_ip4(cache, &rt->dst, fl.saddr);
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}
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skb->ignore_df = 1;
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udp_tunnel_xmit_skb(rt, sock, skb, fl.saddr, fl.daddr, ds,
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ip4_dst_hoplimit(&rt->dst), 0, fl.fl4_sport,
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fl.fl4_dport, false, false);
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goto out;
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err:
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kfree_skb(skb);
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out:
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rcu_read_unlock_bh();
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return ret;
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}
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static int send6(struct wg_device *wg, struct sk_buff *skb,
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struct endpoint *endpoint, u8 ds, struct dst_cache *cache)
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{
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#if IS_ENABLED(CONFIG_IPV6)
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struct flowi6 fl = {
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.saddr = endpoint->src6,
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.daddr = endpoint->addr6.sin6_addr,
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.fl6_dport = endpoint->addr6.sin6_port,
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.flowi6_mark = wg->fwmark,
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.flowi6_oif = endpoint->addr6.sin6_scope_id,
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.flowi6_proto = IPPROTO_UDP
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/* TODO: addr->sin6_flowinfo */
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};
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struct dst_entry *dst = NULL;
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struct sock *sock;
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int ret = 0;
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skb_mark_not_on_list(skb);
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skb->dev = wg->dev;
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skb->mark = wg->fwmark;
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rcu_read_lock_bh();
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sock = rcu_dereference_bh(wg->sock6);
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if (unlikely(!sock)) {
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ret = -ENONET;
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goto err;
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}
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fl.fl6_sport = inet_sk(sock)->inet_sport;
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if (cache)
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dst = dst_cache_get_ip6(cache, &fl.saddr);
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if (!dst) {
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security_sk_classify_flow(sock, flowi6_to_flowi_common(&fl));
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if (unlikely(!ipv6_addr_any(&fl.saddr) &&
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!ipv6_chk_addr(sock_net(sock), &fl.saddr, NULL, 0))) {
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endpoint->src6 = fl.saddr = in6addr_any;
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if (cache)
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dst_cache_reset(cache);
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}
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dst = ipv6_stub->ipv6_dst_lookup_flow(sock_net(sock), sock, &fl,
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NULL);
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if (IS_ERR(dst)) {
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ret = PTR_ERR(dst);
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net_dbg_ratelimited("%s: No route to %pISpfsc, error %d\n",
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wg->dev->name, &endpoint->addr, ret);
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goto err;
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}
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if (cache)
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dst_cache_set_ip6(cache, dst, &fl.saddr);
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}
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skb->ignore_df = 1;
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udp_tunnel6_xmit_skb(dst, sock, skb, skb->dev, &fl.saddr, &fl.daddr, ds,
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ip6_dst_hoplimit(dst), 0, fl.fl6_sport,
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fl.fl6_dport, false);
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goto out;
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err:
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kfree_skb(skb);
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out:
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rcu_read_unlock_bh();
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return ret;
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#else
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kfree_skb(skb);
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return -EAFNOSUPPORT;
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#endif
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}
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int wg_socket_send_skb_to_peer(struct wg_peer *peer, struct sk_buff *skb, u8 ds)
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{
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size_t skb_len = skb->len;
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int ret = -EAFNOSUPPORT;
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read_lock_bh(&peer->endpoint_lock);
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if (peer->endpoint.addr.sa_family == AF_INET)
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ret = send4(peer->device, skb, &peer->endpoint, ds,
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&peer->endpoint_cache);
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else if (peer->endpoint.addr.sa_family == AF_INET6)
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ret = send6(peer->device, skb, &peer->endpoint, ds,
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&peer->endpoint_cache);
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else
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dev_kfree_skb(skb);
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if (likely(!ret))
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peer->tx_bytes += skb_len;
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read_unlock_bh(&peer->endpoint_lock);
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return ret;
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}
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int wg_socket_send_buffer_to_peer(struct wg_peer *peer, void *buffer,
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size_t len, u8 ds)
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{
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struct sk_buff *skb = alloc_skb(len + SKB_HEADER_LEN, GFP_ATOMIC);
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if (unlikely(!skb))
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return -ENOMEM;
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skb_reserve(skb, SKB_HEADER_LEN);
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skb_set_inner_network_header(skb, 0);
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skb_put_data(skb, buffer, len);
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return wg_socket_send_skb_to_peer(peer, skb, ds);
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}
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int wg_socket_send_buffer_as_reply_to_skb(struct wg_device *wg,
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struct sk_buff *in_skb, void *buffer,
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size_t len)
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{
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int ret = 0;
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struct sk_buff *skb;
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struct endpoint endpoint;
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if (unlikely(!in_skb))
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return -EINVAL;
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ret = wg_socket_endpoint_from_skb(&endpoint, in_skb);
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if (unlikely(ret < 0))
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return ret;
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skb = alloc_skb(len + SKB_HEADER_LEN, GFP_ATOMIC);
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if (unlikely(!skb))
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return -ENOMEM;
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skb_reserve(skb, SKB_HEADER_LEN);
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skb_set_inner_network_header(skb, 0);
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skb_put_data(skb, buffer, len);
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if (endpoint.addr.sa_family == AF_INET)
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ret = send4(wg, skb, &endpoint, 0, NULL);
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else if (endpoint.addr.sa_family == AF_INET6)
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ret = send6(wg, skb, &endpoint, 0, NULL);
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/* No other possibilities if the endpoint is valid, which it is,
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* as we checked above.
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*/
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return ret;
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}
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int wg_socket_endpoint_from_skb(struct endpoint *endpoint,
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const struct sk_buff *skb)
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{
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memset(endpoint, 0, sizeof(*endpoint));
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if (skb->protocol == htons(ETH_P_IP)) {
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endpoint->addr4.sin_family = AF_INET;
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endpoint->addr4.sin_port = udp_hdr(skb)->source;
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endpoint->addr4.sin_addr.s_addr = ip_hdr(skb)->saddr;
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endpoint->src4.s_addr = ip_hdr(skb)->daddr;
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endpoint->src_if4 = skb->skb_iif;
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} else if (IS_ENABLED(CONFIG_IPV6) && skb->protocol == htons(ETH_P_IPV6)) {
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endpoint->addr6.sin6_family = AF_INET6;
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endpoint->addr6.sin6_port = udp_hdr(skb)->source;
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endpoint->addr6.sin6_addr = ipv6_hdr(skb)->saddr;
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endpoint->addr6.sin6_scope_id = ipv6_iface_scope_id(
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&ipv6_hdr(skb)->saddr, skb->skb_iif);
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endpoint->src6 = ipv6_hdr(skb)->daddr;
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} else {
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return -EINVAL;
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}
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return 0;
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}
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static bool endpoint_eq(const struct endpoint *a, const struct endpoint *b)
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{
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return (a->addr.sa_family == AF_INET && b->addr.sa_family == AF_INET &&
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a->addr4.sin_port == b->addr4.sin_port &&
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a->addr4.sin_addr.s_addr == b->addr4.sin_addr.s_addr &&
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a->src4.s_addr == b->src4.s_addr && a->src_if4 == b->src_if4) ||
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(a->addr.sa_family == AF_INET6 &&
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b->addr.sa_family == AF_INET6 &&
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a->addr6.sin6_port == b->addr6.sin6_port &&
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ipv6_addr_equal(&a->addr6.sin6_addr, &b->addr6.sin6_addr) &&
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a->addr6.sin6_scope_id == b->addr6.sin6_scope_id &&
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ipv6_addr_equal(&a->src6, &b->src6)) ||
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unlikely(!a->addr.sa_family && !b->addr.sa_family);
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}
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void wg_socket_set_peer_endpoint(struct wg_peer *peer,
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const struct endpoint *endpoint)
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{
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/* First we check unlocked, in order to optimize, since it's pretty rare
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* that an endpoint will change. If we happen to be mid-write, and two
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* CPUs wind up writing the same thing or something slightly different,
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* it doesn't really matter much either.
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*/
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if (endpoint_eq(endpoint, &peer->endpoint))
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return;
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write_lock_bh(&peer->endpoint_lock);
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if (endpoint->addr.sa_family == AF_INET) {
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peer->endpoint.addr4 = endpoint->addr4;
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peer->endpoint.src4 = endpoint->src4;
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peer->endpoint.src_if4 = endpoint->src_if4;
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} else if (IS_ENABLED(CONFIG_IPV6) && endpoint->addr.sa_family == AF_INET6) {
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peer->endpoint.addr6 = endpoint->addr6;
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peer->endpoint.src6 = endpoint->src6;
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} else {
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goto out;
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}
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dst_cache_reset(&peer->endpoint_cache);
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out:
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write_unlock_bh(&peer->endpoint_lock);
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}
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void wg_socket_set_peer_endpoint_from_skb(struct wg_peer *peer,
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const struct sk_buff *skb)
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{
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struct endpoint endpoint;
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if (!wg_socket_endpoint_from_skb(&endpoint, skb))
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wg_socket_set_peer_endpoint(peer, &endpoint);
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}
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void wg_socket_clear_peer_endpoint_src(struct wg_peer *peer)
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{
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write_lock_bh(&peer->endpoint_lock);
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memset(&peer->endpoint.src6, 0, sizeof(peer->endpoint.src6));
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dst_cache_reset_now(&peer->endpoint_cache);
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write_unlock_bh(&peer->endpoint_lock);
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}
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static int wg_receive(struct sock *sk, struct sk_buff *skb)
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{
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struct wg_device *wg;
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if (unlikely(!sk))
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goto err;
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wg = sk->sk_user_data;
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if (unlikely(!wg))
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goto err;
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skb_mark_not_on_list(skb);
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wg_packet_receive(wg, skb);
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return 0;
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err:
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kfree_skb(skb);
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return 0;
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}
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static void sock_free(struct sock *sock)
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{
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if (unlikely(!sock))
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return;
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sk_clear_memalloc(sock);
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udp_tunnel_sock_release(sock->sk_socket);
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}
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static void set_sock_opts(struct socket *sock)
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{
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sock->sk->sk_allocation = GFP_ATOMIC;
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sock->sk->sk_sndbuf = INT_MAX;
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sk_set_memalloc(sock->sk);
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}
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int wg_socket_init(struct wg_device *wg, u16 port)
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{
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struct net *net;
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int ret;
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struct udp_tunnel_sock_cfg cfg = {
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|
|
.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);
|
||
|
|
}
|