Tom Herbert | 2346155 | 2014-09-17 12:25:56 -0700 | [diff] [blame] | 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> |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 11 | #include <net/protocol.h> |
Tom Herbert | 2346155 | 2014-09-17 12:25:56 -0700 | [diff] [blame] | 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; |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 25 | struct udp_offload udp_offloads; |
Tom Herbert | 2346155 | 2014-09-17 12:25:56 -0700 | [diff] [blame] | 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 | |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 67 | static struct sk_buff **fou_gro_receive(struct sk_buff **head, |
Tom Herbert | efc98d0 | 2014-10-03 15:48:08 -0700 | [diff] [blame^] | 68 | struct sk_buff *skb) |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 69 | { |
| 70 | const struct net_offload *ops; |
| 71 | struct sk_buff **pp = NULL; |
| 72 | u8 proto = NAPI_GRO_CB(skb)->proto; |
Tom Herbert | efc98d0 | 2014-10-03 15:48:08 -0700 | [diff] [blame^] | 73 | const struct net_offload **offloads; |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 74 | |
| 75 | rcu_read_lock(); |
Tom Herbert | efc98d0 | 2014-10-03 15:48:08 -0700 | [diff] [blame^] | 76 | offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads; |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 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 | |
Tom Herbert | efc98d0 | 2014-10-03 15:48:08 -0700 | [diff] [blame^] | 89 | static int fou_gro_complete(struct sk_buff *skb, int nhoff) |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 90 | { |
| 91 | const struct net_offload *ops; |
| 92 | u8 proto = NAPI_GRO_CB(skb)->proto; |
| 93 | int err = -ENOSYS; |
Tom Herbert | efc98d0 | 2014-10-03 15:48:08 -0700 | [diff] [blame^] | 94 | const struct net_offload **offloads; |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 95 | |
| 96 | rcu_read_lock(); |
Tom Herbert | efc98d0 | 2014-10-03 15:48:08 -0700 | [diff] [blame^] | 97 | offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads; |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 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 | |
Tom Herbert | 2346155 | 2014-09-17 12:25:56 -0700 | [diff] [blame] | 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 | |
Tom Herbert | efc98d0 | 2014-10-03 15:48:08 -0700 | [diff] [blame^] | 182 | fou->udp_offloads.callbacks.gro_receive = fou_gro_receive; |
| 183 | fou->udp_offloads.callbacks.gro_complete = fou_gro_complete; |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 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 | |
Tom Herbert | 2346155 | 2014-09-17 12:25:56 -0700 | [diff] [blame] | 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) { |
Tom Herbert | afe9332 | 2014-09-17 12:25:57 -0700 | [diff] [blame] | 219 | udp_del_offload(&fou->udp_offloads); |
Tom Herbert | 2346155 | 2014-09-17 12:25:56 -0700 | [diff] [blame] | 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"); |