1 #ifndef _LINUX_DCCP_H 2 #define _LINUX_DCCP_H 3 4 #include <linux/types.h> 5 #include <asm/byteorder.h> 6 7 /** 8 * struct dccp_hdr - generic part of DCCP packet header 9 * 10 * @dccph_sport - Relevant port on the endpoint that sent this packet 11 * @dccph_dport - Relevant port on the other endpoint 12 * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words 13 * @dccph_ccval - Used by the HC-Sender CCID 14 * @dccph_cscov - Parts of the packet that are covered by the Checksum field 15 * @dccph_checksum - Internet checksum, depends on dccph_cscov 16 * @dccph_x - 0 = 24 bit sequence number, 1 = 48 17 * @dccph_type - packet type, see DCCP_PKT_ prefixed macros 18 * @dccph_seq - sequence number high or low order 24 bits, depends on dccph_x 19 */ 20 struct dccp_hdr { 21 __be16 dccph_sport, 22 dccph_dport; 23 __u8 dccph_doff; 24 #if defined(__LITTLE_ENDIAN_BITFIELD) 25 __u8 dccph_cscov:4, 26 dccph_ccval:4; 27 #elif defined(__BIG_ENDIAN_BITFIELD) 28 __u8 dccph_ccval:4, 29 dccph_cscov:4; 30 #else 31 #error "Adjust your <asm/byteorder.h> defines" 32 #endif 33 __sum16 dccph_checksum; 34 #if defined(__LITTLE_ENDIAN_BITFIELD) 35 __u8 dccph_x:1, 36 dccph_type:4, 37 dccph_reserved:3; 38 #elif defined(__BIG_ENDIAN_BITFIELD) 39 __u8 dccph_reserved:3, 40 dccph_type:4, 41 dccph_x:1; 42 #else 43 #error "Adjust your <asm/byteorder.h> defines" 44 #endif 45 __u8 dccph_seq2; 46 __be16 dccph_seq; 47 }; 48 49 /** 50 * struct dccp_hdr_ext - the low bits of a 48 bit seq packet 51 * 52 * @dccph_seq_low - low 24 bits of a 48 bit seq packet 53 */ 54 struct dccp_hdr_ext { 55 __be32 dccph_seq_low; 56 }; 57 58 /** 59 * struct dccp_hdr_request - Connection initiation request header 60 * 61 * @dccph_req_service - Service to which the client app wants to connect 62 */ 63 struct dccp_hdr_request { 64 __be32 dccph_req_service; 65 }; 66 /** 67 * struct dccp_hdr_ack_bits - acknowledgment bits common to most packets 68 * 69 * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR 70 * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR 71 */ 72 struct dccp_hdr_ack_bits { 73 __be16 dccph_reserved1; 74 __be16 dccph_ack_nr_high; 75 __be32 dccph_ack_nr_low; 76 }; 77 /** 78 * struct dccp_hdr_response - Connection initiation response header 79 * 80 * @dccph_resp_ack - 48 bit Acknowledgment Number Subheader (5.3) 81 * @dccph_resp_service - Echoes the Service Code on a received DCCP-Request 82 */ 83 struct dccp_hdr_response { 84 struct dccp_hdr_ack_bits dccph_resp_ack; 85 __be32 dccph_resp_service; 86 }; 87 88 /** 89 * struct dccp_hdr_reset - Unconditionally shut down a connection 90 * 91 * @dccph_reset_ack - 48 bit Acknowledgment Number Subheader (5.6) 92 * @dccph_reset_code - one of %dccp_reset_codes 93 * @dccph_reset_data - the Data 1 ... Data 3 fields from 5.6 94 */ 95 struct dccp_hdr_reset { 96 struct dccp_hdr_ack_bits dccph_reset_ack; 97 __u8 dccph_reset_code, 98 dccph_reset_data[3]; 99 }; 100 101 enum dccp_pkt_type { 102 DCCP_PKT_REQUEST = 0, 103 DCCP_PKT_RESPONSE, 104 DCCP_PKT_DATA, 105 DCCP_PKT_ACK, 106 DCCP_PKT_DATAACK, 107 DCCP_PKT_CLOSEREQ, 108 DCCP_PKT_CLOSE, 109 DCCP_PKT_RESET, 110 DCCP_PKT_SYNC, 111 DCCP_PKT_SYNCACK, 112 DCCP_PKT_INVALID, 113 }; 114 115 #define DCCP_NR_PKT_TYPES DCCP_PKT_INVALID 116 117 static inline unsigned int dccp_packet_hdr_len(const __u8 type) 118 { 119 if (type == DCCP_PKT_DATA) 120 return 0; 121 if (type == DCCP_PKT_DATAACK || 122 type == DCCP_PKT_ACK || 123 type == DCCP_PKT_SYNC || 124 type == DCCP_PKT_SYNCACK || 125 type == DCCP_PKT_CLOSE || 126 type == DCCP_PKT_CLOSEREQ) 127 return sizeof(struct dccp_hdr_ack_bits); 128 if (type == DCCP_PKT_REQUEST) 129 return sizeof(struct dccp_hdr_request); 130 if (type == DCCP_PKT_RESPONSE) 131 return sizeof(struct dccp_hdr_response); 132 return sizeof(struct dccp_hdr_reset); 133 } 134 enum dccp_reset_codes { 135 DCCP_RESET_CODE_UNSPECIFIED = 0, 136 DCCP_RESET_CODE_CLOSED, 137 DCCP_RESET_CODE_ABORTED, 138 DCCP_RESET_CODE_NO_CONNECTION, 139 DCCP_RESET_CODE_PACKET_ERROR, 140 DCCP_RESET_CODE_OPTION_ERROR, 141 DCCP_RESET_CODE_MANDATORY_ERROR, 142 DCCP_RESET_CODE_CONNECTION_REFUSED, 143 DCCP_RESET_CODE_BAD_SERVICE_CODE, 144 DCCP_RESET_CODE_TOO_BUSY, 145 DCCP_RESET_CODE_BAD_INIT_COOKIE, 146 DCCP_RESET_CODE_AGGRESSION_PENALTY, 147 148 DCCP_MAX_RESET_CODES /* Leave at the end! */ 149 }; 150 151 /* DCCP options */ 152 enum { 153 DCCPO_PADDING = 0, 154 DCCPO_MANDATORY = 1, 155 DCCPO_MIN_RESERVED = 3, 156 DCCPO_MAX_RESERVED = 31, 157 DCCPO_CHANGE_L = 32, 158 DCCPO_CONFIRM_L = 33, 159 DCCPO_CHANGE_R = 34, 160 DCCPO_CONFIRM_R = 35, 161 DCCPO_NDP_COUNT = 37, 162 DCCPO_ACK_VECTOR_0 = 38, 163 DCCPO_ACK_VECTOR_1 = 39, 164 DCCPO_TIMESTAMP = 41, 165 DCCPO_TIMESTAMP_ECHO = 42, 166 DCCPO_ELAPSED_TIME = 43, 167 DCCPO_MAX = 45, 168 DCCPO_MIN_RX_CCID_SPECIFIC = 128, /* from sender to receiver */ 169 DCCPO_MAX_RX_CCID_SPECIFIC = 191, 170 DCCPO_MIN_TX_CCID_SPECIFIC = 192, /* from receiver to sender */ 171 DCCPO_MAX_TX_CCID_SPECIFIC = 255, 172 }; 173 /* maximum size of a single TLV-encoded DCCP option (sans type/len bytes) */ 174 #define DCCP_SINGLE_OPT_MAXLEN 253 175 176 /* DCCP CCIDS */ 177 enum { 178 DCCPC_CCID2 = 2, 179 DCCPC_CCID3 = 3, 180 }; 181 182 /* DCCP features (RFC 4340 section 6.4) */ 183 enum dccp_feature_numbers { 184 DCCPF_RESERVED = 0, 185 DCCPF_CCID = 1, 186 DCCPF_SHORT_SEQNOS = 2, 187 DCCPF_SEQUENCE_WINDOW = 3, 188 DCCPF_ECN_INCAPABLE = 4, 189 DCCPF_ACK_RATIO = 5, 190 DCCPF_SEND_ACK_VECTOR = 6, 191 DCCPF_SEND_NDP_COUNT = 7, 192 DCCPF_MIN_CSUM_COVER = 8, 193 DCCPF_DATA_CHECKSUM = 9, 194 /* 10-127 reserved */ 195 DCCPF_MIN_CCID_SPECIFIC = 128, 196 DCCPF_SEND_LEV_RATE = 192, /* RFC 4342, sec. 8.4 */ 197 DCCPF_MAX_CCID_SPECIFIC = 255, 198 }; 199 200 /* DCCP socket control message types for cmsg */ 201 enum dccp_cmsg_type { 202 DCCP_SCM_PRIORITY = 1, 203 DCCP_SCM_QPOLICY_MAX = 0xFFFF, 204 /* ^-- Up to here reserved exclusively for qpolicy parameters */ 205 DCCP_SCM_MAX 206 }; 207 208 /* DCCP priorities for outgoing/queued packets */ 209 enum dccp_packet_dequeueing_policy { 210 DCCPQ_POLICY_SIMPLE, 211 DCCPQ_POLICY_PRIO, 212 DCCPQ_POLICY_MAX 213 }; 214 215 /* DCCP socket options */ 216 #define DCCP_SOCKOPT_PACKET_SIZE 1 /* XXX deprecated, without effect */ 217 #define DCCP_SOCKOPT_SERVICE 2 218 #define DCCP_SOCKOPT_CHANGE_L 3 219 #define DCCP_SOCKOPT_CHANGE_R 4 220 #define DCCP_SOCKOPT_GET_CUR_MPS 5 221 #define DCCP_SOCKOPT_SERVER_TIMEWAIT 6 222 #define DCCP_SOCKOPT_SEND_CSCOV 10 223 #define DCCP_SOCKOPT_RECV_CSCOV 11 224 #define DCCP_SOCKOPT_AVAILABLE_CCIDS 12 225 #define DCCP_SOCKOPT_CCID 13 226 #define DCCP_SOCKOPT_TX_CCID 14 227 #define DCCP_SOCKOPT_RX_CCID 15 228 #define DCCP_SOCKOPT_QPOLICY_ID 16 229 #define DCCP_SOCKOPT_QPOLICY_TXQLEN 17 230 #define DCCP_SOCKOPT_CCID_RX_INFO 128 231 #define DCCP_SOCKOPT_CCID_TX_INFO 192 232 233 /* maximum number of services provided on the same listening port */ 234 #define DCCP_SERVICE_LIST_MAX_LEN 32 235 236 #ifdef __KERNEL__ 237 238 #include <linux/in.h> 239 #include <linux/ktime.h> 240 #include <linux/list.h> 241 #include <linux/uio.h> 242 #include <linux/workqueue.h> 243 244 #include <net/inet_connection_sock.h> 245 #include <net/inet_sock.h> 246 #include <net/inet_timewait_sock.h> 247 #include <net/tcp_states.h> 248 249 enum dccp_state { 250 DCCP_OPEN = TCP_ESTABLISHED, 251 DCCP_REQUESTING = TCP_SYN_SENT, 252 DCCP_LISTEN = TCP_LISTEN, 253 DCCP_RESPOND = TCP_SYN_RECV, 254 /* 255 * States involved in closing a DCCP connection: 256 * 1) ACTIVE_CLOSEREQ is entered by a server sending a CloseReq. 257 * 258 * 2) CLOSING can have three different meanings (RFC 4340, 8.3): 259 * a. Client has performed active-close, has sent a Close to the server 260 * from state OPEN or PARTOPEN, and is waiting for the final Reset 261 * (in this case, SOCK_DONE == 1). 262 * b. Client is asked to perform passive-close, by receiving a CloseReq 263 * in (PART)OPEN state. It sends a Close and waits for final Reset 264 * (in this case, SOCK_DONE == 0). 265 * c. Server performs an active-close as in (a), keeps TIMEWAIT state. 266 * 267 * 3) The following intermediate states are employed to give passively 268 * closing nodes a chance to process their unread data: 269 * - PASSIVE_CLOSE (from OPEN => CLOSED) and 270 * - PASSIVE_CLOSEREQ (from (PART)OPEN to CLOSING; case (b) above). 271 */ 272 DCCP_ACTIVE_CLOSEREQ = TCP_FIN_WAIT1, 273 DCCP_PASSIVE_CLOSE = TCP_CLOSE_WAIT, /* any node receiving a Close */ 274 DCCP_CLOSING = TCP_CLOSING, 275 DCCP_TIME_WAIT = TCP_TIME_WAIT, 276 DCCP_CLOSED = TCP_CLOSE, 277 DCCP_PARTOPEN = TCP_MAX_STATES, 278 DCCP_PASSIVE_CLOSEREQ, /* clients receiving CloseReq */ 279 DCCP_MAX_STATES 280 }; 281 282 #define DCCP_STATE_MASK 0x1f 283 284 enum { 285 DCCPF_OPEN = TCPF_ESTABLISHED, 286 DCCPF_REQUESTING = TCPF_SYN_SENT, 287 DCCPF_LISTEN = TCPF_LISTEN, 288 DCCPF_RESPOND = TCPF_SYN_RECV, 289 DCCPF_ACTIVE_CLOSEREQ = TCPF_FIN_WAIT1, 290 DCCPF_CLOSING = TCPF_CLOSING, 291 DCCPF_TIME_WAIT = TCPF_TIME_WAIT, 292 DCCPF_CLOSED = TCPF_CLOSE, 293 DCCPF_PARTOPEN = (1 << DCCP_PARTOPEN), 294 }; 295 296 static inline struct dccp_hdr *dccp_hdr(const struct sk_buff *skb) 297 { 298 return (struct dccp_hdr *)skb_transport_header(skb); 299 } 300 301 static inline struct dccp_hdr *dccp_zeroed_hdr(struct sk_buff *skb, int headlen) 302 { 303 skb_push(skb, headlen); 304 skb_reset_transport_header(skb); 305 return memset(skb_transport_header(skb), 0, headlen); 306 } 307 308 static inline struct dccp_hdr_ext *dccp_hdrx(const struct dccp_hdr *dh) 309 { 310 return (struct dccp_hdr_ext *)((unsigned char *)dh + sizeof(*dh)); 311 } 312 313 static inline unsigned int __dccp_basic_hdr_len(const struct dccp_hdr *dh) 314 { 315 return sizeof(*dh) + (dh->dccph_x ? sizeof(struct dccp_hdr_ext) : 0); 316 } 317 318 static inline unsigned int dccp_basic_hdr_len(const struct sk_buff *skb) 319 { 320 const struct dccp_hdr *dh = dccp_hdr(skb); 321 return __dccp_basic_hdr_len(dh); 322 } 323 324 static inline __u64 dccp_hdr_seq(const struct dccp_hdr *dh) 325 { 326 __u64 seq_nr = ntohs(dh->dccph_seq); 327 328 if (dh->dccph_x != 0) 329 seq_nr = (seq_nr << 32) + ntohl(dccp_hdrx(dh)->dccph_seq_low); 330 else 331 seq_nr += (u32)dh->dccph_seq2 << 16; 332 333 return seq_nr; 334 } 335 336 static inline struct dccp_hdr_request *dccp_hdr_request(struct sk_buff *skb) 337 { 338 return (struct dccp_hdr_request *)(skb_transport_header(skb) + 339 dccp_basic_hdr_len(skb)); 340 } 341 342 static inline struct dccp_hdr_ack_bits *dccp_hdr_ack_bits(const struct sk_buff *skb) 343 { 344 return (struct dccp_hdr_ack_bits *)(skb_transport_header(skb) + 345 dccp_basic_hdr_len(skb)); 346 } 347 348 static inline u64 dccp_hdr_ack_seq(const struct sk_buff *skb) 349 { 350 const struct dccp_hdr_ack_bits *dhack = dccp_hdr_ack_bits(skb); 351 return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) + ntohl(dhack->dccph_ack_nr_low); 352 } 353 354 static inline struct dccp_hdr_response *dccp_hdr_response(struct sk_buff *skb) 355 { 356 return (struct dccp_hdr_response *)(skb_transport_header(skb) + 357 dccp_basic_hdr_len(skb)); 358 } 359 360 static inline struct dccp_hdr_reset *dccp_hdr_reset(struct sk_buff *skb) 361 { 362 return (struct dccp_hdr_reset *)(skb_transport_header(skb) + 363 dccp_basic_hdr_len(skb)); 364 } 365 366 static inline unsigned int __dccp_hdr_len(const struct dccp_hdr *dh) 367 { 368 return __dccp_basic_hdr_len(dh) + 369 dccp_packet_hdr_len(dh->dccph_type); 370 } 371 372 static inline unsigned int dccp_hdr_len(const struct sk_buff *skb) 373 { 374 return __dccp_hdr_len(dccp_hdr(skb)); 375 } 376 377 /** 378 * struct dccp_request_sock - represent DCCP-specific connection request 379 * @dreq_inet_rsk: structure inherited from 380 * @dreq_iss: initial sequence number sent on the Response (RFC 4340, 7.1) 381 * @dreq_isr: initial sequence number received on the Request 382 * @dreq_service: service code present on the Request (there is just one) 383 * @dreq_featneg: feature negotiation options for this connection 384 * The following two fields are analogous to the ones in dccp_sock: 385 * @dreq_timestamp_echo: last received timestamp to echo (13.1) 386 * @dreq_timestamp_echo: the time of receiving the last @dreq_timestamp_echo 387 */ 388 struct dccp_request_sock { 389 struct inet_request_sock dreq_inet_rsk; 390 __u64 dreq_iss; 391 __u64 dreq_isr; 392 __be32 dreq_service; 393 struct list_head dreq_featneg; 394 __u32 dreq_timestamp_echo; 395 __u32 dreq_timestamp_time; 396 }; 397 398 static inline struct dccp_request_sock *dccp_rsk(const struct request_sock *req) 399 { 400 return (struct dccp_request_sock *)req; 401 } 402 403 extern struct inet_timewait_death_row dccp_death_row; 404 405 extern int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq, 406 struct sk_buff *skb); 407 408 struct dccp_options_received { 409 u64 dccpor_ndp:48; 410 u32 dccpor_timestamp; 411 u32 dccpor_timestamp_echo; 412 u32 dccpor_elapsed_time; 413 }; 414 415 struct ccid; 416 417 enum dccp_role { 418 DCCP_ROLE_UNDEFINED, 419 DCCP_ROLE_LISTEN, 420 DCCP_ROLE_CLIENT, 421 DCCP_ROLE_SERVER, 422 }; 423 424 struct dccp_service_list { 425 __u32 dccpsl_nr; 426 __be32 dccpsl_list[0]; 427 }; 428 429 #define DCCP_SERVICE_INVALID_VALUE htonl((__u32)-1) 430 #define DCCP_SERVICE_CODE_IS_ABSENT 0 431 432 static inline int dccp_list_has_service(const struct dccp_service_list *sl, 433 const __be32 service) 434 { 435 if (likely(sl != NULL)) { 436 u32 i = sl->dccpsl_nr; 437 while (i--) 438 if (sl->dccpsl_list[i] == service) 439 return 1; 440 } 441 return 0; 442 } 443 444 struct dccp_ackvec; 445 446 /** 447 * struct dccp_sock - DCCP socket state 448 * 449 * @dccps_swl - sequence number window low 450 * @dccps_swh - sequence number window high 451 * @dccps_awl - acknowledgement number window low 452 * @dccps_awh - acknowledgement number window high 453 * @dccps_iss - initial sequence number sent 454 * @dccps_isr - initial sequence number received 455 * @dccps_osr - first OPEN sequence number received 456 * @dccps_gss - greatest sequence number sent 457 * @dccps_gsr - greatest valid sequence number received 458 * @dccps_gar - greatest valid ack number received on a non-Sync; initialized to %dccps_iss 459 * @dccps_service - first (passive sock) or unique (active sock) service code 460 * @dccps_service_list - second .. last service code on passive socket 461 * @dccps_timestamp_echo - latest timestamp received on a TIMESTAMP option 462 * @dccps_timestamp_time - time of receiving latest @dccps_timestamp_echo 463 * @dccps_l_ack_ratio - feature-local Ack Ratio 464 * @dccps_r_ack_ratio - feature-remote Ack Ratio 465 * @dccps_l_seq_win - local Sequence Window (influences ack number validity) 466 * @dccps_r_seq_win - remote Sequence Window (influences seq number validity) 467 * @dccps_pcslen - sender partial checksum coverage (via sockopt) 468 * @dccps_pcrlen - receiver partial checksum coverage (via sockopt) 469 * @dccps_send_ndp_count - local Send NDP Count feature (7.7.2) 470 * @dccps_ndp_count - number of Non Data Packets since last data packet 471 * @dccps_mss_cache - current value of MSS (path MTU minus header sizes) 472 * @dccps_rate_last - timestamp for rate-limiting DCCP-Sync (RFC 4340, 7.5.4) 473 * @dccps_featneg - tracks feature-negotiation state (mostly during handshake) 474 * @dccps_hc_rx_ackvec - rx half connection ack vector 475 * @dccps_hc_rx_ccid - CCID used for the receiver (or receiving half-connection) 476 * @dccps_hc_tx_ccid - CCID used for the sender (or sending half-connection) 477 * @dccps_options_received - parsed set of retrieved options 478 * @dccps_qpolicy - TX dequeueing policy, one of %dccp_packet_dequeueing_policy 479 * @dccps_tx_qlen - maximum length of the TX queue 480 * @dccps_role - role of this sock, one of %dccp_role 481 * @dccps_hc_rx_insert_options - receiver wants to add options when acking 482 * @dccps_hc_tx_insert_options - sender wants to add options when sending 483 * @dccps_server_timewait - server holds timewait state on close (RFC 4340, 8.3) 484 * @dccps_sync_scheduled - flag which signals "send out-of-band message soon" 485 * @dccps_xmitlet - tasklet scheduled by the TX CCID to dequeue data packets 486 * @dccps_xmit_timer - used by the TX CCID to delay sending (rate-based pacing) 487 * @dccps_syn_rtt - RTT sample from Request/Response exchange (in usecs) 488 */ 489 struct dccp_sock { 490 /* inet_connection_sock has to be the first member of dccp_sock */ 491 struct inet_connection_sock dccps_inet_connection; 492 #define dccps_syn_rtt dccps_inet_connection.icsk_ack.lrcvtime 493 __u64 dccps_swl; 494 __u64 dccps_swh; 495 __u64 dccps_awl; 496 __u64 dccps_awh; 497 __u64 dccps_iss; 498 __u64 dccps_isr; 499 __u64 dccps_osr; 500 __u64 dccps_gss; 501 __u64 dccps_gsr; 502 __u64 dccps_gar; 503 __be32 dccps_service; 504 __u32 dccps_mss_cache; 505 struct dccp_service_list *dccps_service_list; 506 __u32 dccps_timestamp_echo; 507 __u32 dccps_timestamp_time; 508 __u16 dccps_l_ack_ratio; 509 __u16 dccps_r_ack_ratio; 510 __u64 dccps_l_seq_win:48; 511 __u64 dccps_r_seq_win:48; 512 __u8 dccps_pcslen:4; 513 __u8 dccps_pcrlen:4; 514 __u8 dccps_send_ndp_count:1; 515 __u64 dccps_ndp_count:48; 516 unsigned long dccps_rate_last; 517 struct list_head dccps_featneg; 518 struct dccp_ackvec *dccps_hc_rx_ackvec; 519 struct ccid *dccps_hc_rx_ccid; 520 struct ccid *dccps_hc_tx_ccid; 521 struct dccp_options_received dccps_options_received; 522 __u8 dccps_qpolicy; 523 __u32 dccps_tx_qlen; 524 enum dccp_role dccps_role:2; 525 __u8 dccps_hc_rx_insert_options:1; 526 __u8 dccps_hc_tx_insert_options:1; 527 __u8 dccps_server_timewait:1; 528 __u8 dccps_sync_scheduled:1; 529 struct tasklet_struct dccps_xmitlet; 530 struct timer_list dccps_xmit_timer; 531 }; 532 533 static inline struct dccp_sock *dccp_sk(const struct sock *sk) 534 { 535 return (struct dccp_sock *)sk; 536 } 537 538 static inline const char *dccp_role(const struct sock *sk) 539 { 540 switch (dccp_sk(sk)->dccps_role) { 541 case DCCP_ROLE_UNDEFINED: return "undefined"; 542 case DCCP_ROLE_LISTEN: return "listen"; 543 case DCCP_ROLE_SERVER: return "server"; 544 case DCCP_ROLE_CLIENT: return "client"; 545 } 546 return NULL; 547 } 548 549 #endif /* __KERNEL__ */ 550 551 #endif /* _LINUX_DCCP_H */ 552