xref: /linux/include/net/vxlan.h (revision 5c35a02c545a7bbe77f3a1ae337d9e29beed079b)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __NET_VXLAN_H
3 #define __NET_VXLAN_H 1
4 
5 #include <linux/if_vlan.h>
6 #include <net/udp_tunnel.h>
7 #include <net/dst_metadata.h>
8 #include <net/udp_tunnel.h>
9 
10 /* VXLAN protocol (RFC 7348) header:
11  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
12  * |R|R|R|R|I|R|R|R|               Reserved                        |
13  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
14  * |                VXLAN Network Identifier (VNI) |   Reserved    |
15  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
16  *
17  * I = VXLAN Network Identifier (VNI) present.
18  */
19 struct vxlanhdr {
20 	__be32 vx_flags;
21 	__be32 vx_vni;
22 };
23 
24 /* VXLAN header flags. */
25 #define VXLAN_HF_VNI	cpu_to_be32(BIT(27))
26 
27 #define VXLAN_N_VID     (1u << 24)
28 #define VXLAN_VID_MASK  (VXLAN_N_VID - 1)
29 #define VXLAN_VNI_MASK	cpu_to_be32(VXLAN_VID_MASK << 8)
30 #define VXLAN_HLEN (sizeof(struct udphdr) + sizeof(struct vxlanhdr))
31 
32 #define VNI_HASH_BITS	10
33 #define VNI_HASH_SIZE	(1<<VNI_HASH_BITS)
34 #define FDB_HASH_BITS	8
35 #define FDB_HASH_SIZE	(1<<FDB_HASH_BITS)
36 
37 /* Remote checksum offload for VXLAN (VXLAN_F_REMCSUM_[RT]X):
38  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
39  * |R|R|R|R|I|R|R|R|R|R|C|              Reserved                   |
40  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
41  * |           VXLAN Network Identifier (VNI)      |O| Csum start  |
42  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
43  *
44  * C = Remote checksum offload bit. When set indicates that the
45  *     remote checksum offload data is present.
46  *
47  * O = Offset bit. Indicates the checksum offset relative to
48  *     checksum start.
49  *
50  * Csum start = Checksum start divided by two.
51  *
52  * http://tools.ietf.org/html/draft-herbert-vxlan-rco
53  */
54 
55 /* VXLAN-RCO header flags. */
56 #define VXLAN_HF_RCO	cpu_to_be32(BIT(21))
57 
58 /* Remote checksum offload header option */
59 #define VXLAN_RCO_MASK	cpu_to_be32(0x7f)  /* Last byte of vni field */
60 #define VXLAN_RCO_UDP	cpu_to_be32(0x80)  /* Indicate UDP RCO (TCP when not set *) */
61 #define VXLAN_RCO_SHIFT	1		   /* Left shift of start */
62 #define VXLAN_RCO_SHIFT_MASK ((1 << VXLAN_RCO_SHIFT) - 1)
63 #define VXLAN_MAX_REMCSUM_START (0x7f << VXLAN_RCO_SHIFT)
64 
65 /*
66  * VXLAN Group Based Policy Extension (VXLAN_F_GBP):
67  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
68  * |G|R|R|R|I|R|R|R|R|D|R|R|A|R|R|R|        Group Policy ID        |
69  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
70  * |                VXLAN Network Identifier (VNI) |   Reserved    |
71  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
72  *
73  * G = Group Policy ID present.
74  *
75  * D = Don't Learn bit. When set, this bit indicates that the egress
76  *     VTEP MUST NOT learn the source address of the encapsulated frame.
77  *
78  * A = Indicates that the group policy has already been applied to
79  *     this packet. Policies MUST NOT be applied by devices when the
80  *     A bit is set.
81  *
82  * https://tools.ietf.org/html/draft-smith-vxlan-group-policy
83  */
84 struct vxlanhdr_gbp {
85 	u8	vx_flags;
86 #ifdef __LITTLE_ENDIAN_BITFIELD
87 	u8	reserved_flags1:3,
88 		policy_applied:1,
89 		reserved_flags2:2,
90 		dont_learn:1,
91 		reserved_flags3:1;
92 #elif defined(__BIG_ENDIAN_BITFIELD)
93 	u8	reserved_flags1:1,
94 		dont_learn:1,
95 		reserved_flags2:2,
96 		policy_applied:1,
97 		reserved_flags3:3;
98 #else
99 #error	"Please fix <asm/byteorder.h>"
100 #endif
101 	__be16	policy_id;
102 	__be32	vx_vni;
103 };
104 
105 /* VXLAN-GBP header flags. */
106 #define VXLAN_HF_GBP	cpu_to_be32(BIT(31))
107 
108 #define VXLAN_GBP_USED_BITS (VXLAN_HF_GBP | cpu_to_be32(0xFFFFFF))
109 
110 /* skb->mark mapping
111  *
112  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
113  * |R|R|R|R|R|R|R|R|R|D|R|R|A|R|R|R|        Group Policy ID        |
114  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
115  */
116 #define VXLAN_GBP_DONT_LEARN		(BIT(6) << 16)
117 #define VXLAN_GBP_POLICY_APPLIED	(BIT(3) << 16)
118 #define VXLAN_GBP_ID_MASK		(0xFFFF)
119 
120 /*
121  * VXLAN Generic Protocol Extension (VXLAN_F_GPE):
122  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
123  * |R|R|Ver|I|P|R|O|       Reserved                |Next Protocol  |
124  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
125  * |                VXLAN Network Identifier (VNI) |   Reserved    |
126  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
127  *
128  * Ver = Version. Indicates VXLAN GPE protocol version.
129  *
130  * P = Next Protocol Bit. The P bit is set to indicate that the
131  *     Next Protocol field is present.
132  *
133  * O = OAM Flag Bit. The O bit is set to indicate that the packet
134  *     is an OAM packet.
135  *
136  * Next Protocol = This 8 bit field indicates the protocol header
137  * immediately following the VXLAN GPE header.
138  *
139  * https://tools.ietf.org/html/draft-ietf-nvo3-vxlan-gpe-01
140  */
141 
142 struct vxlanhdr_gpe {
143 #if defined(__LITTLE_ENDIAN_BITFIELD)
144 	u8	oam_flag:1,
145 		reserved_flags1:1,
146 		np_applied:1,
147 		instance_applied:1,
148 		version:2,
149 		reserved_flags2:2;
150 #elif defined(__BIG_ENDIAN_BITFIELD)
151 	u8	reserved_flags2:2,
152 		version:2,
153 		instance_applied:1,
154 		np_applied:1,
155 		reserved_flags1:1,
156 		oam_flag:1;
157 #endif
158 	u8	reserved_flags3;
159 	u8	reserved_flags4;
160 	u8	next_protocol;
161 	__be32	vx_vni;
162 };
163 
164 /* VXLAN-GPE header flags. */
165 #define VXLAN_HF_VER	cpu_to_be32(BIT(29) | BIT(28))
166 #define VXLAN_HF_NP	cpu_to_be32(BIT(26))
167 #define VXLAN_HF_OAM	cpu_to_be32(BIT(24))
168 
169 #define VXLAN_GPE_USED_BITS (VXLAN_HF_VER | VXLAN_HF_NP | VXLAN_HF_OAM | \
170 			     cpu_to_be32(0xff))
171 
172 struct vxlan_metadata {
173 	u32		gbp;
174 };
175 
176 /* per UDP socket information */
177 struct vxlan_sock {
178 	struct hlist_node hlist;
179 	struct socket	 *sock;
180 	struct hlist_head vni_list[VNI_HASH_SIZE];
181 	refcount_t	  refcnt;
182 	u32		  flags;
183 };
184 
185 union vxlan_addr {
186 	struct sockaddr_in sin;
187 	struct sockaddr_in6 sin6;
188 	struct sockaddr sa;
189 };
190 
191 struct vxlan_rdst {
192 	union vxlan_addr	 remote_ip;
193 	__be16			 remote_port;
194 	__be32			 remote_vni;
195 	u32			 remote_ifindex;
196 	struct list_head	 list;
197 	struct rcu_head		 rcu;
198 	struct dst_cache	 dst_cache;
199 };
200 
201 struct vxlan_config {
202 	union vxlan_addr	remote_ip;
203 	union vxlan_addr	saddr;
204 	__be32			vni;
205 	int			remote_ifindex;
206 	int			mtu;
207 	__be16			dst_port;
208 	u16			port_min;
209 	u16			port_max;
210 	u8			tos;
211 	u8			ttl;
212 	__be32			label;
213 	u32			flags;
214 	unsigned long		age_interval;
215 	unsigned int		addrmax;
216 	bool			no_share;
217 };
218 
219 struct vxlan_dev_node {
220 	struct hlist_node hlist;
221 	struct vxlan_dev *vxlan;
222 };
223 
224 /* Pseudo network device */
225 struct vxlan_dev {
226 	struct vxlan_dev_node hlist4;	/* vni hash table for IPv4 socket */
227 #if IS_ENABLED(CONFIG_IPV6)
228 	struct vxlan_dev_node hlist6;	/* vni hash table for IPv6 socket */
229 #endif
230 	struct list_head  next;		/* vxlan's per namespace list */
231 	struct vxlan_sock __rcu *vn4_sock;	/* listening socket for IPv4 */
232 #if IS_ENABLED(CONFIG_IPV6)
233 	struct vxlan_sock __rcu *vn6_sock;	/* listening socket for IPv6 */
234 #endif
235 	struct net_device *dev;
236 	struct net	  *net;		/* netns for packet i/o */
237 	struct vxlan_rdst default_dst;	/* default destination */
238 
239 	struct timer_list age_timer;
240 	spinlock_t	  hash_lock;
241 	unsigned int	  addrcnt;
242 	struct gro_cells  gro_cells;
243 
244 	struct vxlan_config	cfg;
245 
246 	struct hlist_head fdb_head[FDB_HASH_SIZE];
247 };
248 
249 #define VXLAN_F_LEARN			0x01
250 #define VXLAN_F_PROXY			0x02
251 #define VXLAN_F_RSC			0x04
252 #define VXLAN_F_L2MISS			0x08
253 #define VXLAN_F_L3MISS			0x10
254 #define VXLAN_F_IPV6			0x20
255 #define VXLAN_F_UDP_ZERO_CSUM_TX	0x40
256 #define VXLAN_F_UDP_ZERO_CSUM6_TX	0x80
257 #define VXLAN_F_UDP_ZERO_CSUM6_RX	0x100
258 #define VXLAN_F_REMCSUM_TX		0x200
259 #define VXLAN_F_REMCSUM_RX		0x400
260 #define VXLAN_F_GBP			0x800
261 #define VXLAN_F_REMCSUM_NOPARTIAL	0x1000
262 #define VXLAN_F_COLLECT_METADATA	0x2000
263 #define VXLAN_F_GPE			0x4000
264 #define VXLAN_F_IPV6_LINKLOCAL		0x8000
265 #define VXLAN_F_TTL_INHERIT		0x10000
266 
267 /* Flags that are used in the receive path. These flags must match in
268  * order for a socket to be shareable
269  */
270 #define VXLAN_F_RCV_FLAGS		(VXLAN_F_GBP |			\
271 					 VXLAN_F_GPE |			\
272 					 VXLAN_F_UDP_ZERO_CSUM6_RX |	\
273 					 VXLAN_F_REMCSUM_RX |		\
274 					 VXLAN_F_REMCSUM_NOPARTIAL |	\
275 					 VXLAN_F_COLLECT_METADATA)
276 
277 /* Flags that can be set together with VXLAN_F_GPE. */
278 #define VXLAN_F_ALLOWED_GPE		(VXLAN_F_GPE |			\
279 					 VXLAN_F_IPV6 |			\
280 					 VXLAN_F_IPV6_LINKLOCAL |	\
281 					 VXLAN_F_UDP_ZERO_CSUM_TX |	\
282 					 VXLAN_F_UDP_ZERO_CSUM6_TX |	\
283 					 VXLAN_F_UDP_ZERO_CSUM6_RX |	\
284 					 VXLAN_F_COLLECT_METADATA)
285 
286 struct net_device *vxlan_dev_create(struct net *net, const char *name,
287 				    u8 name_assign_type, struct vxlan_config *conf);
288 
289 static inline netdev_features_t vxlan_features_check(struct sk_buff *skb,
290 						     netdev_features_t features)
291 {
292 	u8 l4_hdr = 0;
293 
294 	if (!skb->encapsulation)
295 		return features;
296 
297 	switch (vlan_get_protocol(skb)) {
298 	case htons(ETH_P_IP):
299 		l4_hdr = ip_hdr(skb)->protocol;
300 		break;
301 	case htons(ETH_P_IPV6):
302 		l4_hdr = ipv6_hdr(skb)->nexthdr;
303 		break;
304 	default:
305 		return features;
306 	}
307 
308 	if ((l4_hdr == IPPROTO_UDP) &&
309 	    (skb->inner_protocol_type != ENCAP_TYPE_ETHER ||
310 	     skb->inner_protocol != htons(ETH_P_TEB) ||
311 	     (skb_inner_mac_header(skb) - skb_transport_header(skb) !=
312 	      sizeof(struct udphdr) + sizeof(struct vxlanhdr)) ||
313 	     (skb->ip_summed != CHECKSUM_NONE &&
314 	      !can_checksum_protocol(features, inner_eth_hdr(skb)->h_proto))))
315 		return features & ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK);
316 
317 	return features;
318 }
319 
320 /* IP header + UDP + VXLAN + Ethernet header */
321 #define VXLAN_HEADROOM (20 + 8 + 8 + 14)
322 /* IPv6 header + UDP + VXLAN + Ethernet header */
323 #define VXLAN6_HEADROOM (40 + 8 + 8 + 14)
324 
325 static inline struct vxlanhdr *vxlan_hdr(struct sk_buff *skb)
326 {
327 	return (struct vxlanhdr *)(udp_hdr(skb) + 1);
328 }
329 
330 static inline __be32 vxlan_vni(__be32 vni_field)
331 {
332 #if defined(__BIG_ENDIAN)
333 	return (__force __be32)((__force u32)vni_field >> 8);
334 #else
335 	return (__force __be32)((__force u32)(vni_field & VXLAN_VNI_MASK) << 8);
336 #endif
337 }
338 
339 static inline __be32 vxlan_vni_field(__be32 vni)
340 {
341 #if defined(__BIG_ENDIAN)
342 	return (__force __be32)((__force u32)vni << 8);
343 #else
344 	return (__force __be32)((__force u32)vni >> 8);
345 #endif
346 }
347 
348 static inline size_t vxlan_rco_start(__be32 vni_field)
349 {
350 	return be32_to_cpu(vni_field & VXLAN_RCO_MASK) << VXLAN_RCO_SHIFT;
351 }
352 
353 static inline size_t vxlan_rco_offset(__be32 vni_field)
354 {
355 	return (vni_field & VXLAN_RCO_UDP) ?
356 		offsetof(struct udphdr, check) :
357 		offsetof(struct tcphdr, check);
358 }
359 
360 static inline __be32 vxlan_compute_rco(unsigned int start, unsigned int offset)
361 {
362 	__be32 vni_field = cpu_to_be32(start >> VXLAN_RCO_SHIFT);
363 
364 	if (offset == offsetof(struct udphdr, check))
365 		vni_field |= VXLAN_RCO_UDP;
366 	return vni_field;
367 }
368 
369 static inline unsigned short vxlan_get_sk_family(struct vxlan_sock *vs)
370 {
371 	return vs->sock->sk->sk_family;
372 }
373 
374 #endif
375