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23461551 TH |
1 | #include <linux/module.h> |
2 | #include <linux/errno.h> | |
3 | #include <linux/socket.h> | |
4 | #include <linux/skbuff.h> | |
5 | #include <linux/ip.h> | |
6 | #include <linux/udp.h> | |
7 | #include <linux/types.h> | |
8 | #include <linux/kernel.h> | |
9 | #include <net/genetlink.h> | |
10 | #include <net/ip.h> | |
afe93325 | 11 | #include <net/protocol.h> |
23461551 TH |
12 | #include <net/udp.h> |
13 | #include <net/udp_tunnel.h> | |
14 | #include <net/xfrm.h> | |
15 | #include <uapi/linux/fou.h> | |
16 | #include <uapi/linux/genetlink.h> | |
17 | ||
18 | static DEFINE_SPINLOCK(fou_lock); | |
19 | static LIST_HEAD(fou_list); | |
20 | ||
21 | struct fou { | |
22 | struct socket *sock; | |
23 | u8 protocol; | |
24 | u16 port; | |
afe93325 | 25 | struct udp_offload udp_offloads; |
23461551 TH |
26 | struct list_head list; |
27 | }; | |
28 | ||
29 | struct fou_cfg { | |
30 | u8 protocol; | |
31 | struct udp_port_cfg udp_config; | |
32 | }; | |
33 | ||
34 | static inline struct fou *fou_from_sock(struct sock *sk) | |
35 | { | |
36 | return sk->sk_user_data; | |
37 | } | |
38 | ||
39 | static int fou_udp_encap_recv_deliver(struct sk_buff *skb, | |
40 | u8 protocol, size_t len) | |
41 | { | |
42 | struct iphdr *iph = ip_hdr(skb); | |
43 | ||
44 | /* Remove 'len' bytes from the packet (UDP header and | |
45 | * FOU header if present), modify the protocol to the one | |
46 | * we found, and then call rcv_encap. | |
47 | */ | |
48 | iph->tot_len = htons(ntohs(iph->tot_len) - len); | |
49 | __skb_pull(skb, len); | |
50 | skb_postpull_rcsum(skb, udp_hdr(skb), len); | |
51 | skb_reset_transport_header(skb); | |
52 | ||
53 | return -protocol; | |
54 | } | |
55 | ||
56 | static int fou_udp_recv(struct sock *sk, struct sk_buff *skb) | |
57 | { | |
58 | struct fou *fou = fou_from_sock(sk); | |
59 | ||
60 | if (!fou) | |
61 | return 1; | |
62 | ||
63 | return fou_udp_encap_recv_deliver(skb, fou->protocol, | |
64 | sizeof(struct udphdr)); | |
65 | } | |
66 | ||
afe93325 | 67 | static struct sk_buff **fou_gro_receive(struct sk_buff **head, |
efc98d08 | 68 | struct sk_buff *skb) |
afe93325 TH |
69 | { |
70 | const struct net_offload *ops; | |
71 | struct sk_buff **pp = NULL; | |
72 | u8 proto = NAPI_GRO_CB(skb)->proto; | |
efc98d08 | 73 | const struct net_offload **offloads; |
afe93325 TH |
74 | |
75 | rcu_read_lock(); | |
efc98d08 | 76 | offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads; |
afe93325 TH |
77 | ops = rcu_dereference(offloads[proto]); |
78 | if (!ops || !ops->callbacks.gro_receive) | |
79 | goto out_unlock; | |
80 | ||
81 | pp = ops->callbacks.gro_receive(head, skb); | |
82 | ||
83 | out_unlock: | |
84 | rcu_read_unlock(); | |
85 | ||
86 | return pp; | |
87 | } | |
88 | ||
efc98d08 | 89 | static int fou_gro_complete(struct sk_buff *skb, int nhoff) |
afe93325 TH |
90 | { |
91 | const struct net_offload *ops; | |
92 | u8 proto = NAPI_GRO_CB(skb)->proto; | |
93 | int err = -ENOSYS; | |
efc98d08 | 94 | const struct net_offload **offloads; |
afe93325 TH |
95 | |
96 | rcu_read_lock(); | |
efc98d08 | 97 | offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads; |
afe93325 TH |
98 | ops = rcu_dereference(offloads[proto]); |
99 | if (WARN_ON(!ops || !ops->callbacks.gro_complete)) | |
100 | goto out_unlock; | |
101 | ||
102 | err = ops->callbacks.gro_complete(skb, nhoff); | |
103 | ||
104 | out_unlock: | |
105 | rcu_read_unlock(); | |
106 | ||
107 | return err; | |
108 | } | |
109 | ||
23461551 TH |
110 | static int fou_add_to_port_list(struct fou *fou) |
111 | { | |
112 | struct fou *fout; | |
113 | ||
114 | spin_lock(&fou_lock); | |
115 | list_for_each_entry(fout, &fou_list, list) { | |
116 | if (fou->port == fout->port) { | |
117 | spin_unlock(&fou_lock); | |
118 | return -EALREADY; | |
119 | } | |
120 | } | |
121 | ||
122 | list_add(&fou->list, &fou_list); | |
123 | spin_unlock(&fou_lock); | |
124 | ||
125 | return 0; | |
126 | } | |
127 | ||
128 | static void fou_release(struct fou *fou) | |
129 | { | |
130 | struct socket *sock = fou->sock; | |
131 | struct sock *sk = sock->sk; | |
132 | ||
133 | udp_del_offload(&fou->udp_offloads); | |
134 | ||
135 | list_del(&fou->list); | |
136 | ||
137 | /* Remove hooks into tunnel socket */ | |
138 | sk->sk_user_data = NULL; | |
139 | ||
140 | sock_release(sock); | |
141 | ||
142 | kfree(fou); | |
143 | } | |
144 | ||
145 | static int fou_create(struct net *net, struct fou_cfg *cfg, | |
146 | struct socket **sockp) | |
147 | { | |
148 | struct fou *fou = NULL; | |
149 | int err; | |
150 | struct socket *sock = NULL; | |
151 | struct sock *sk; | |
152 | ||
153 | /* Open UDP socket */ | |
154 | err = udp_sock_create(net, &cfg->udp_config, &sock); | |
155 | if (err < 0) | |
156 | goto error; | |
157 | ||
158 | /* Allocate FOU port structure */ | |
159 | fou = kzalloc(sizeof(*fou), GFP_KERNEL); | |
160 | if (!fou) { | |
161 | err = -ENOMEM; | |
162 | goto error; | |
163 | } | |
164 | ||
165 | sk = sock->sk; | |
166 | ||
167 | /* Mark socket as an encapsulation socket. See net/ipv4/udp.c */ | |
168 | fou->protocol = cfg->protocol; | |
169 | fou->port = cfg->udp_config.local_udp_port; | |
170 | udp_sk(sk)->encap_rcv = fou_udp_recv; | |
171 | ||
172 | udp_sk(sk)->encap_type = 1; | |
173 | udp_encap_enable(); | |
174 | ||
175 | sk->sk_user_data = fou; | |
176 | fou->sock = sock; | |
177 | ||
178 | udp_set_convert_csum(sk, true); | |
179 | ||
180 | sk->sk_allocation = GFP_ATOMIC; | |
181 | ||
efc98d08 TH |
182 | fou->udp_offloads.callbacks.gro_receive = fou_gro_receive; |
183 | fou->udp_offloads.callbacks.gro_complete = fou_gro_complete; | |
afe93325 TH |
184 | fou->udp_offloads.port = cfg->udp_config.local_udp_port; |
185 | fou->udp_offloads.ipproto = cfg->protocol; | |
186 | ||
187 | if (cfg->udp_config.family == AF_INET) { | |
188 | err = udp_add_offload(&fou->udp_offloads); | |
189 | if (err) | |
190 | goto error; | |
191 | } | |
192 | ||
23461551 TH |
193 | err = fou_add_to_port_list(fou); |
194 | if (err) | |
195 | goto error; | |
196 | ||
197 | if (sockp) | |
198 | *sockp = sock; | |
199 | ||
200 | return 0; | |
201 | ||
202 | error: | |
203 | kfree(fou); | |
204 | if (sock) | |
205 | sock_release(sock); | |
206 | ||
207 | return err; | |
208 | } | |
209 | ||
210 | static int fou_destroy(struct net *net, struct fou_cfg *cfg) | |
211 | { | |
212 | struct fou *fou; | |
213 | u16 port = cfg->udp_config.local_udp_port; | |
214 | int err = -EINVAL; | |
215 | ||
216 | spin_lock(&fou_lock); | |
217 | list_for_each_entry(fou, &fou_list, list) { | |
218 | if (fou->port == port) { | |
afe93325 | 219 | udp_del_offload(&fou->udp_offloads); |
23461551 TH |
220 | fou_release(fou); |
221 | err = 0; | |
222 | break; | |
223 | } | |
224 | } | |
225 | spin_unlock(&fou_lock); | |
226 | ||
227 | return err; | |
228 | } | |
229 | ||
230 | static struct genl_family fou_nl_family = { | |
231 | .id = GENL_ID_GENERATE, | |
232 | .hdrsize = 0, | |
233 | .name = FOU_GENL_NAME, | |
234 | .version = FOU_GENL_VERSION, | |
235 | .maxattr = FOU_ATTR_MAX, | |
236 | .netnsok = true, | |
237 | }; | |
238 | ||
239 | static struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = { | |
240 | [FOU_ATTR_PORT] = { .type = NLA_U16, }, | |
241 | [FOU_ATTR_AF] = { .type = NLA_U8, }, | |
242 | [FOU_ATTR_IPPROTO] = { .type = NLA_U8, }, | |
243 | }; | |
244 | ||
245 | static int parse_nl_config(struct genl_info *info, | |
246 | struct fou_cfg *cfg) | |
247 | { | |
248 | memset(cfg, 0, sizeof(*cfg)); | |
249 | ||
250 | cfg->udp_config.family = AF_INET; | |
251 | ||
252 | if (info->attrs[FOU_ATTR_AF]) { | |
253 | u8 family = nla_get_u8(info->attrs[FOU_ATTR_AF]); | |
254 | ||
255 | if (family != AF_INET && family != AF_INET6) | |
256 | return -EINVAL; | |
257 | ||
258 | cfg->udp_config.family = family; | |
259 | } | |
260 | ||
261 | if (info->attrs[FOU_ATTR_PORT]) { | |
262 | u16 port = nla_get_u16(info->attrs[FOU_ATTR_PORT]); | |
263 | ||
264 | cfg->udp_config.local_udp_port = port; | |
265 | } | |
266 | ||
267 | if (info->attrs[FOU_ATTR_IPPROTO]) | |
268 | cfg->protocol = nla_get_u8(info->attrs[FOU_ATTR_IPPROTO]); | |
269 | ||
270 | return 0; | |
271 | } | |
272 | ||
273 | static int fou_nl_cmd_add_port(struct sk_buff *skb, struct genl_info *info) | |
274 | { | |
275 | struct fou_cfg cfg; | |
276 | int err; | |
277 | ||
278 | err = parse_nl_config(info, &cfg); | |
279 | if (err) | |
280 | return err; | |
281 | ||
282 | return fou_create(&init_net, &cfg, NULL); | |
283 | } | |
284 | ||
285 | static int fou_nl_cmd_rm_port(struct sk_buff *skb, struct genl_info *info) | |
286 | { | |
287 | struct fou_cfg cfg; | |
288 | ||
289 | parse_nl_config(info, &cfg); | |
290 | ||
291 | return fou_destroy(&init_net, &cfg); | |
292 | } | |
293 | ||
294 | static const struct genl_ops fou_nl_ops[] = { | |
295 | { | |
296 | .cmd = FOU_CMD_ADD, | |
297 | .doit = fou_nl_cmd_add_port, | |
298 | .policy = fou_nl_policy, | |
299 | .flags = GENL_ADMIN_PERM, | |
300 | }, | |
301 | { | |
302 | .cmd = FOU_CMD_DEL, | |
303 | .doit = fou_nl_cmd_rm_port, | |
304 | .policy = fou_nl_policy, | |
305 | .flags = GENL_ADMIN_PERM, | |
306 | }, | |
307 | }; | |
308 | ||
309 | static int __init fou_init(void) | |
310 | { | |
311 | int ret; | |
312 | ||
313 | ret = genl_register_family_with_ops(&fou_nl_family, | |
314 | fou_nl_ops); | |
315 | ||
316 | return ret; | |
317 | } | |
318 | ||
319 | static void __exit fou_fini(void) | |
320 | { | |
321 | struct fou *fou, *next; | |
322 | ||
323 | genl_unregister_family(&fou_nl_family); | |
324 | ||
325 | /* Close all the FOU sockets */ | |
326 | ||
327 | spin_lock(&fou_lock); | |
328 | list_for_each_entry_safe(fou, next, &fou_list, list) | |
329 | fou_release(fou); | |
330 | spin_unlock(&fou_lock); | |
331 | } | |
332 | ||
333 | module_init(fou_init); | |
334 | module_exit(fou_fini); | |
335 | MODULE_AUTHOR("Tom Herbert <therbert@google.com>"); | |
336 | MODULE_LICENSE("GPL"); |