// SPDX-License-Identifier: GPL-2.0/* * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. 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, 0);	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 = ip6_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, 0);	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);} 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->sk, &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->sk);			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->sk, &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);}