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