xref: /linux/net/ipv4/udp_tunnel_core.c (revision c5288cda69ee2d8607f5026bd599a5cebf0ee783)
1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/module.h>
3 #include <linux/errno.h>
4 #include <linux/socket.h>
5 #include <linux/kernel.h>
6 #include <net/dst_metadata.h>
7 #include <net/udp.h>
8 #include <net/udp_tunnel.h>
9 
10 int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
11 		     struct socket **sockp)
12 {
13 	int err;
14 	struct socket *sock = NULL;
15 	struct sockaddr_in udp_addr;
16 
17 	err = sock_create_kern(net, AF_INET, SOCK_DGRAM, 0, &sock);
18 	if (err < 0)
19 		goto error;
20 
21 	if (cfg->bind_ifindex) {
22 		err = sock_bindtoindex(sock->sk, cfg->bind_ifindex, true);
23 		if (err < 0)
24 			goto error;
25 	}
26 
27 	udp_addr.sin_family = AF_INET;
28 	udp_addr.sin_addr = cfg->local_ip;
29 	udp_addr.sin_port = cfg->local_udp_port;
30 	err = kernel_bind(sock, (struct sockaddr *)&udp_addr,
31 			  sizeof(udp_addr));
32 	if (err < 0)
33 		goto error;
34 
35 	if (cfg->peer_udp_port) {
36 		udp_addr.sin_family = AF_INET;
37 		udp_addr.sin_addr = cfg->peer_ip;
38 		udp_addr.sin_port = cfg->peer_udp_port;
39 		err = kernel_connect(sock, (struct sockaddr *)&udp_addr,
40 				     sizeof(udp_addr), 0);
41 		if (err < 0)
42 			goto error;
43 	}
44 
45 	sock->sk->sk_no_check_tx = !cfg->use_udp_checksums;
46 
47 	*sockp = sock;
48 	return 0;
49 
50 error:
51 	if (sock) {
52 		kernel_sock_shutdown(sock, SHUT_RDWR);
53 		sock_release(sock);
54 	}
55 	*sockp = NULL;
56 	return err;
57 }
58 EXPORT_SYMBOL(udp_sock_create4);
59 
60 void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
61 			   struct udp_tunnel_sock_cfg *cfg)
62 {
63 	struct sock *sk = sock->sk;
64 
65 	/* Disable multicast loopback */
66 	inet_clear_bit(MC_LOOP, sk);
67 
68 	/* Enable CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE conversion */
69 	inet_inc_convert_csum(sk);
70 
71 	rcu_assign_sk_user_data(sk, cfg->sk_user_data);
72 
73 	udp_sk(sk)->encap_type = cfg->encap_type;
74 	udp_sk(sk)->encap_rcv = cfg->encap_rcv;
75 	udp_sk(sk)->encap_err_rcv = cfg->encap_err_rcv;
76 	udp_sk(sk)->encap_err_lookup = cfg->encap_err_lookup;
77 	udp_sk(sk)->encap_destroy = cfg->encap_destroy;
78 	udp_sk(sk)->gro_receive = cfg->gro_receive;
79 	udp_sk(sk)->gro_complete = cfg->gro_complete;
80 
81 	udp_tunnel_encap_enable(sk);
82 }
83 EXPORT_SYMBOL_GPL(setup_udp_tunnel_sock);
84 
85 void udp_tunnel_push_rx_port(struct net_device *dev, struct socket *sock,
86 			     unsigned short type)
87 {
88 	struct sock *sk = sock->sk;
89 	struct udp_tunnel_info ti;
90 
91 	ti.type = type;
92 	ti.sa_family = sk->sk_family;
93 	ti.port = inet_sk(sk)->inet_sport;
94 
95 	udp_tunnel_nic_add_port(dev, &ti);
96 }
97 EXPORT_SYMBOL_GPL(udp_tunnel_push_rx_port);
98 
99 void udp_tunnel_drop_rx_port(struct net_device *dev, struct socket *sock,
100 			     unsigned short type)
101 {
102 	struct sock *sk = sock->sk;
103 	struct udp_tunnel_info ti;
104 
105 	ti.type = type;
106 	ti.sa_family = sk->sk_family;
107 	ti.port = inet_sk(sk)->inet_sport;
108 
109 	udp_tunnel_nic_del_port(dev, &ti);
110 }
111 EXPORT_SYMBOL_GPL(udp_tunnel_drop_rx_port);
112 
113 /* Notify netdevs that UDP port started listening */
114 void udp_tunnel_notify_add_rx_port(struct socket *sock, unsigned short type)
115 {
116 	struct sock *sk = sock->sk;
117 	struct net *net = sock_net(sk);
118 	struct udp_tunnel_info ti;
119 	struct net_device *dev;
120 
121 	ti.type = type;
122 	ti.sa_family = sk->sk_family;
123 	ti.port = inet_sk(sk)->inet_sport;
124 
125 	rcu_read_lock();
126 	for_each_netdev_rcu(net, dev) {
127 		udp_tunnel_nic_add_port(dev, &ti);
128 	}
129 	rcu_read_unlock();
130 }
131 EXPORT_SYMBOL_GPL(udp_tunnel_notify_add_rx_port);
132 
133 /* Notify netdevs that UDP port is no more listening */
134 void udp_tunnel_notify_del_rx_port(struct socket *sock, unsigned short type)
135 {
136 	struct sock *sk = sock->sk;
137 	struct net *net = sock_net(sk);
138 	struct udp_tunnel_info ti;
139 	struct net_device *dev;
140 
141 	ti.type = type;
142 	ti.sa_family = sk->sk_family;
143 	ti.port = inet_sk(sk)->inet_sport;
144 
145 	rcu_read_lock();
146 	for_each_netdev_rcu(net, dev) {
147 		udp_tunnel_nic_del_port(dev, &ti);
148 	}
149 	rcu_read_unlock();
150 }
151 EXPORT_SYMBOL_GPL(udp_tunnel_notify_del_rx_port);
152 
153 void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
154 			 __be32 src, __be32 dst, __u8 tos, __u8 ttl,
155 			 __be16 df, __be16 src_port, __be16 dst_port,
156 			 bool xnet, bool nocheck)
157 {
158 	struct udphdr *uh;
159 
160 	__skb_push(skb, sizeof(*uh));
161 	skb_reset_transport_header(skb);
162 	uh = udp_hdr(skb);
163 
164 	uh->dest = dst_port;
165 	uh->source = src_port;
166 	uh->len = htons(skb->len);
167 
168 	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
169 
170 	udp_set_csum(nocheck, skb, src, dst, skb->len);
171 
172 	iptunnel_xmit(sk, rt, skb, src, dst, IPPROTO_UDP, tos, ttl, df, xnet);
173 }
174 EXPORT_SYMBOL_GPL(udp_tunnel_xmit_skb);
175 
176 void udp_tunnel_sock_release(struct socket *sock)
177 {
178 	rcu_assign_sk_user_data(sock->sk, NULL);
179 	synchronize_rcu();
180 	kernel_sock_shutdown(sock, SHUT_RDWR);
181 	sock_release(sock);
182 }
183 EXPORT_SYMBOL_GPL(udp_tunnel_sock_release);
184 
185 struct metadata_dst *udp_tun_rx_dst(struct sk_buff *skb,  unsigned short family,
186 				    const unsigned long *flags,
187 				    __be64 tunnel_id, int md_size)
188 {
189 	struct metadata_dst *tun_dst;
190 	struct ip_tunnel_info *info;
191 
192 	if (family == AF_INET)
193 		tun_dst = ip_tun_rx_dst(skb, flags, tunnel_id, md_size);
194 	else
195 		tun_dst = ipv6_tun_rx_dst(skb, flags, tunnel_id, md_size);
196 	if (!tun_dst)
197 		return NULL;
198 
199 	info = &tun_dst->u.tun_info;
200 	info->key.tp_src = udp_hdr(skb)->source;
201 	info->key.tp_dst = udp_hdr(skb)->dest;
202 	if (udp_hdr(skb)->check)
203 		__set_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags);
204 	return tun_dst;
205 }
206 EXPORT_SYMBOL_GPL(udp_tun_rx_dst);
207 
208 struct rtable *udp_tunnel_dst_lookup(struct sk_buff *skb,
209 				     struct net_device *dev,
210 				     struct net *net, int oif,
211 				     __be32 *saddr,
212 				     const struct ip_tunnel_key *key,
213 				     __be16 sport, __be16 dport, u8 tos,
214 				     struct dst_cache *dst_cache)
215 {
216 	struct rtable *rt = NULL;
217 	struct flowi4 fl4;
218 
219 #ifdef CONFIG_DST_CACHE
220 	if (dst_cache) {
221 		rt = dst_cache_get_ip4(dst_cache, saddr);
222 		if (rt)
223 			return rt;
224 	}
225 #endif
226 
227 	memset(&fl4, 0, sizeof(fl4));
228 	fl4.flowi4_mark = skb->mark;
229 	fl4.flowi4_proto = IPPROTO_UDP;
230 	fl4.flowi4_oif = oif;
231 	fl4.daddr = key->u.ipv4.dst;
232 	fl4.saddr = key->u.ipv4.src;
233 	fl4.fl4_dport = dport;
234 	fl4.fl4_sport = sport;
235 	fl4.flowi4_tos = RT_TOS(tos);
236 	fl4.flowi4_flags = key->flow_flags;
237 
238 	rt = ip_route_output_key(net, &fl4);
239 	if (IS_ERR(rt)) {
240 		netdev_dbg(dev, "no route to %pI4\n", &fl4.daddr);
241 		return ERR_PTR(-ENETUNREACH);
242 	}
243 	if (rt->dst.dev == dev) { /* is this necessary? */
244 		netdev_dbg(dev, "circular route to %pI4\n", &fl4.daddr);
245 		ip_rt_put(rt);
246 		return ERR_PTR(-ELOOP);
247 	}
248 #ifdef CONFIG_DST_CACHE
249 	if (dst_cache)
250 		dst_cache_set_ip4(dst_cache, &rt->dst, fl4.saddr);
251 #endif
252 	*saddr = fl4.saddr;
253 	return rt;
254 }
255 EXPORT_SYMBOL_GPL(udp_tunnel_dst_lookup);
256 
257 MODULE_DESCRIPTION("IPv4 Foo over UDP tunnel driver");
258 MODULE_LICENSE("GPL");
259