1 #ifndef _DCCP_H 2 #define _DCCP_H 3 /* 4 * net/dccp/dccp.h 5 * 6 * An implementation of the DCCP protocol 7 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br> 8 * Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz> 9 * 10 * This program is free software; you can redistribute it and/or modify it 11 * under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 */ 14 15 #include <linux/dccp.h> 16 #include <linux/ktime.h> 17 #include <net/snmp.h> 18 #include <net/sock.h> 19 #include <net/tcp.h> 20 #include "ackvec.h" 21 22 /* 23 * DCCP - specific warning and debugging macros. 24 */ 25 #define DCCP_WARN(fmt, a...) LIMIT_NETDEBUG(KERN_WARNING "%s: " fmt, \ 26 __func__, ##a) 27 #define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \ 28 __FILE__, __LINE__, __func__) 29 #define DCCP_BUG(a...) do { DCCP_CRIT("BUG: " a); dump_stack(); } while(0) 30 #define DCCP_BUG_ON(cond) do { if (unlikely((cond) != 0)) \ 31 DCCP_BUG("\"%s\" holds (exception!)", \ 32 __stringify(cond)); \ 33 } while (0) 34 35 #define DCCP_PRINTK(enable, fmt, args...) do { if (enable) \ 36 printk(fmt, ##args); \ 37 } while(0) 38 #define DCCP_PR_DEBUG(enable, fmt, a...) DCCP_PRINTK(enable, KERN_DEBUG \ 39 "%s: " fmt, __func__, ##a) 40 41 #ifdef CONFIG_IP_DCCP_DEBUG 42 extern bool dccp_debug; 43 #define dccp_pr_debug(format, a...) DCCP_PR_DEBUG(dccp_debug, format, ##a) 44 #define dccp_pr_debug_cat(format, a...) DCCP_PRINTK(dccp_debug, format, ##a) 45 #define dccp_debug(fmt, a...) dccp_pr_debug_cat(KERN_DEBUG fmt, ##a) 46 #else 47 #define dccp_pr_debug(format, a...) 48 #define dccp_pr_debug_cat(format, a...) 49 #define dccp_debug(format, a...) 50 #endif 51 52 extern struct inet_hashinfo dccp_hashinfo; 53 54 extern struct percpu_counter dccp_orphan_count; 55 56 void dccp_time_wait(struct sock *sk, int state, int timeo); 57 58 /* 59 * Set safe upper bounds for header and option length. Since Data Offset is 8 60 * bits (RFC 4340, sec. 5.1), the total header length can never be more than 61 * 4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1): 62 * - DCCP-Response with ACK Subheader and 4 bytes of Service code OR 63 * - DCCP-Reset with ACK Subheader and 4 bytes of Reset Code fields 64 * Hence a safe upper bound for the maximum option length is 1020-28 = 992 65 */ 66 #define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(uint32_t)) 67 #define DCCP_MAX_PACKET_HDR 28 68 #define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR) 69 #define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER) 70 71 /* Upper bound for initial feature-negotiation overhead (padded to 32 bits) */ 72 #define DCCP_FEATNEG_OVERHEAD (32 * sizeof(uint32_t)) 73 74 #define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT 75 * state, about 60 seconds */ 76 77 /* RFC 1122, 4.2.3.1 initial RTO value */ 78 #define DCCP_TIMEOUT_INIT ((unsigned int)(3 * HZ)) 79 80 /* 81 * The maximum back-off value for retransmissions. This is needed for 82 * - retransmitting client-Requests (sec. 8.1.1), 83 * - retransmitting Close/CloseReq when closing (sec. 8.3), 84 * - feature-negotiation retransmission (sec. 6.6.3), 85 * - Acks in client-PARTOPEN state (sec. 8.1.5). 86 */ 87 #define DCCP_RTO_MAX ((unsigned int)(64 * HZ)) 88 89 /* 90 * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4 91 */ 92 #define DCCP_SANE_RTT_MIN 100 93 #define DCCP_FALLBACK_RTT (USEC_PER_SEC / 5) 94 #define DCCP_SANE_RTT_MAX (3 * USEC_PER_SEC) 95 96 /* sysctl variables for DCCP */ 97 extern int sysctl_dccp_request_retries; 98 extern int sysctl_dccp_retries1; 99 extern int sysctl_dccp_retries2; 100 extern int sysctl_dccp_tx_qlen; 101 extern int sysctl_dccp_sync_ratelimit; 102 103 /* 104 * 48-bit sequence number arithmetic (signed and unsigned) 105 */ 106 #define INT48_MIN 0x800000000000LL /* 2^47 */ 107 #define UINT48_MAX 0xFFFFFFFFFFFFLL /* 2^48 - 1 */ 108 #define COMPLEMENT48(x) (0x1000000000000LL - (x)) /* 2^48 - x */ 109 #define TO_SIGNED48(x) (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x))) 110 #define TO_UNSIGNED48(x) (((x) >= 0)? (x) : COMPLEMENT48(-(x))) 111 #define ADD48(a, b) (((a) + (b)) & UINT48_MAX) 112 #define SUB48(a, b) ADD48((a), COMPLEMENT48(b)) 113 114 static inline void dccp_set_seqno(u64 *seqno, u64 value) 115 { 116 *seqno = value & UINT48_MAX; 117 } 118 119 static inline void dccp_inc_seqno(u64 *seqno) 120 { 121 *seqno = ADD48(*seqno, 1); 122 } 123 124 /* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */ 125 static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2) 126 { 127 u64 delta = SUB48(seqno2, seqno1); 128 129 return TO_SIGNED48(delta); 130 } 131 132 /* is seq1 < seq2 ? */ 133 static inline int before48(const u64 seq1, const u64 seq2) 134 { 135 return (s64)((seq2 << 16) - (seq1 << 16)) > 0; 136 } 137 138 /* is seq1 > seq2 ? */ 139 #define after48(seq1, seq2) before48(seq2, seq1) 140 141 /* is seq2 <= seq1 <= seq3 ? */ 142 static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3) 143 { 144 return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16); 145 } 146 147 static inline u64 max48(const u64 seq1, const u64 seq2) 148 { 149 return after48(seq1, seq2) ? seq1 : seq2; 150 } 151 152 /** 153 * dccp_loss_count - Approximate the number of lost data packets in a burst loss 154 * @s1: last known sequence number before the loss ('hole') 155 * @s2: first sequence number seen after the 'hole' 156 * @ndp: NDP count on packet with sequence number @s2 157 */ 158 static inline u64 dccp_loss_count(const u64 s1, const u64 s2, const u64 ndp) 159 { 160 s64 delta = dccp_delta_seqno(s1, s2); 161 162 WARN_ON(delta < 0); 163 delta -= ndp + 1; 164 165 return delta > 0 ? delta : 0; 166 } 167 168 /** 169 * dccp_loss_free - Evaluate condition for data loss from RFC 4340, 7.7.1 170 */ 171 static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp) 172 { 173 return dccp_loss_count(s1, s2, ndp) == 0; 174 } 175 176 enum { 177 DCCP_MIB_NUM = 0, 178 DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */ 179 DCCP_MIB_ESTABRESETS, /* EstabResets */ 180 DCCP_MIB_CURRESTAB, /* CurrEstab */ 181 DCCP_MIB_OUTSEGS, /* OutSegs */ 182 DCCP_MIB_OUTRSTS, 183 DCCP_MIB_ABORTONTIMEOUT, 184 DCCP_MIB_TIMEOUTS, 185 DCCP_MIB_ABORTFAILED, 186 DCCP_MIB_PASSIVEOPENS, 187 DCCP_MIB_ATTEMPTFAILS, 188 DCCP_MIB_OUTDATAGRAMS, 189 DCCP_MIB_INERRS, 190 DCCP_MIB_OPTMANDATORYERROR, 191 DCCP_MIB_INVALIDOPT, 192 __DCCP_MIB_MAX 193 }; 194 195 #define DCCP_MIB_MAX __DCCP_MIB_MAX 196 struct dccp_mib { 197 unsigned long mibs[DCCP_MIB_MAX]; 198 }; 199 200 DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics); 201 #define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field) 202 #define DCCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(dccp_statistics, field) 203 #define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field) 204 205 /* 206 * Checksumming routines 207 */ 208 static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb) 209 { 210 const struct dccp_hdr* dh = dccp_hdr(skb); 211 212 if (dh->dccph_cscov == 0) 213 return skb->len; 214 return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32); 215 } 216 217 static inline void dccp_csum_outgoing(struct sk_buff *skb) 218 { 219 unsigned int cov = dccp_csum_coverage(skb); 220 221 if (cov >= skb->len) 222 dccp_hdr(skb)->dccph_cscov = 0; 223 224 skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0); 225 } 226 227 void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb); 228 229 int dccp_retransmit_skb(struct sock *sk); 230 231 void dccp_send_ack(struct sock *sk); 232 void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, 233 struct request_sock *rsk); 234 235 void dccp_send_sync(struct sock *sk, const u64 seq, 236 const enum dccp_pkt_type pkt_type); 237 238 /* 239 * TX Packet Dequeueing Interface 240 */ 241 void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb); 242 bool dccp_qpolicy_full(struct sock *sk); 243 void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb); 244 struct sk_buff *dccp_qpolicy_top(struct sock *sk); 245 struct sk_buff *dccp_qpolicy_pop(struct sock *sk); 246 bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param); 247 248 /* 249 * TX Packet Output and TX Timers 250 */ 251 void dccp_write_xmit(struct sock *sk); 252 void dccp_write_space(struct sock *sk); 253 void dccp_flush_write_queue(struct sock *sk, long *time_budget); 254 255 void dccp_init_xmit_timers(struct sock *sk); 256 static inline void dccp_clear_xmit_timers(struct sock *sk) 257 { 258 inet_csk_clear_xmit_timers(sk); 259 } 260 261 unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu); 262 263 const char *dccp_packet_name(const int type); 264 265 void dccp_set_state(struct sock *sk, const int state); 266 void dccp_done(struct sock *sk); 267 268 int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp, 269 struct sk_buff const *skb); 270 271 int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb); 272 273 struct sock *dccp_create_openreq_child(struct sock *sk, 274 const struct request_sock *req, 275 const struct sk_buff *skb); 276 277 int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); 278 279 struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb, 280 struct request_sock *req, 281 struct dst_entry *dst); 282 struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, 283 struct request_sock *req, 284 struct request_sock **prev); 285 286 int dccp_child_process(struct sock *parent, struct sock *child, 287 struct sk_buff *skb); 288 int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, 289 struct dccp_hdr *dh, unsigned int len); 290 int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, 291 const struct dccp_hdr *dh, const unsigned int len); 292 293 int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized); 294 void dccp_destroy_sock(struct sock *sk); 295 296 void dccp_close(struct sock *sk, long timeout); 297 struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, 298 struct request_sock *req); 299 300 int dccp_connect(struct sock *sk); 301 int dccp_disconnect(struct sock *sk, int flags); 302 int dccp_getsockopt(struct sock *sk, int level, int optname, 303 char __user *optval, int __user *optlen); 304 int dccp_setsockopt(struct sock *sk, int level, int optname, 305 char __user *optval, unsigned int optlen); 306 #ifdef CONFIG_COMPAT 307 int compat_dccp_getsockopt(struct sock *sk, int level, int optname, 308 char __user *optval, int __user *optlen); 309 int compat_dccp_setsockopt(struct sock *sk, int level, int optname, 310 char __user *optval, unsigned int optlen); 311 #endif 312 int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg); 313 int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 314 size_t size); 315 int dccp_recvmsg(struct kiocb *iocb, struct sock *sk, 316 struct msghdr *msg, size_t len, int nonblock, int flags, 317 int *addr_len); 318 void dccp_shutdown(struct sock *sk, int how); 319 int inet_dccp_listen(struct socket *sock, int backlog); 320 unsigned int dccp_poll(struct file *file, struct socket *sock, 321 poll_table *wait); 322 int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 323 324 struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *skb); 325 int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code); 326 void dccp_send_close(struct sock *sk, const int active); 327 int dccp_invalid_packet(struct sk_buff *skb); 328 u32 dccp_sample_rtt(struct sock *sk, long delta); 329 330 static inline int dccp_bad_service_code(const struct sock *sk, 331 const __be32 service) 332 { 333 const struct dccp_sock *dp = dccp_sk(sk); 334 335 if (dp->dccps_service == service) 336 return 0; 337 return !dccp_list_has_service(dp->dccps_service_list, service); 338 } 339 340 /** 341 * dccp_skb_cb - DCCP per-packet control information 342 * @dccpd_type: one of %dccp_pkt_type (or unknown) 343 * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1 344 * @dccpd_reset_code: one of %dccp_reset_codes 345 * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code) 346 * @dccpd_opt_len: total length of all options (5.8) in the packet 347 * @dccpd_seq: sequence number 348 * @dccpd_ack_seq: acknowledgment number subheader field value 349 * 350 * This is used for transmission as well as for reception. 351 */ 352 struct dccp_skb_cb { 353 union { 354 struct inet_skb_parm h4; 355 #if IS_ENABLED(CONFIG_IPV6) 356 struct inet6_skb_parm h6; 357 #endif 358 } header; 359 __u8 dccpd_type:4; 360 __u8 dccpd_ccval:4; 361 __u8 dccpd_reset_code, 362 dccpd_reset_data[3]; 363 __u16 dccpd_opt_len; 364 __u64 dccpd_seq; 365 __u64 dccpd_ack_seq; 366 }; 367 368 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0])) 369 370 /* RFC 4340, sec. 7.7 */ 371 static inline int dccp_non_data_packet(const struct sk_buff *skb) 372 { 373 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type; 374 375 return type == DCCP_PKT_ACK || 376 type == DCCP_PKT_CLOSE || 377 type == DCCP_PKT_CLOSEREQ || 378 type == DCCP_PKT_RESET || 379 type == DCCP_PKT_SYNC || 380 type == DCCP_PKT_SYNCACK; 381 } 382 383 /* RFC 4340, sec. 7.7 */ 384 static inline int dccp_data_packet(const struct sk_buff *skb) 385 { 386 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type; 387 388 return type == DCCP_PKT_DATA || 389 type == DCCP_PKT_DATAACK || 390 type == DCCP_PKT_REQUEST || 391 type == DCCP_PKT_RESPONSE; 392 } 393 394 static inline int dccp_packet_without_ack(const struct sk_buff *skb) 395 { 396 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type; 397 398 return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST; 399 } 400 401 #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2) 402 403 static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss) 404 { 405 struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh + 406 sizeof(*dh)); 407 dh->dccph_seq2 = 0; 408 dh->dccph_seq = htons((gss >> 32) & 0xfffff); 409 dhx->dccph_seq_low = htonl(gss & 0xffffffff); 410 } 411 412 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack, 413 const u64 gsr) 414 { 415 dhack->dccph_reserved1 = 0; 416 dhack->dccph_ack_nr_high = htons(gsr >> 32); 417 dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff); 418 } 419 420 static inline void dccp_update_gsr(struct sock *sk, u64 seq) 421 { 422 struct dccp_sock *dp = dccp_sk(sk); 423 424 if (after48(seq, dp->dccps_gsr)) 425 dp->dccps_gsr = seq; 426 /* Sequence validity window depends on remote Sequence Window (7.5.1) */ 427 dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4); 428 /* 429 * Adjust SWL so that it is not below ISR. In contrast to RFC 4340, 430 * 7.5.1 we perform this check beyond the initial handshake: W/W' are 431 * always > 32, so for the first W/W' packets in the lifetime of a 432 * connection we always have to adjust SWL. 433 * A second reason why we are doing this is that the window depends on 434 * the feature-remote value of Sequence Window: nothing stops the peer 435 * from updating this value while we are busy adjusting SWL for the 436 * first W packets (we would have to count from scratch again then). 437 * Therefore it is safer to always make sure that the Sequence Window 438 * is not artificially extended by a peer who grows SWL downwards by 439 * continually updating the feature-remote Sequence-Window. 440 * If sequence numbers wrap it is bad luck. But that will take a while 441 * (48 bit), and this measure prevents Sequence-number attacks. 442 */ 443 if (before48(dp->dccps_swl, dp->dccps_isr)) 444 dp->dccps_swl = dp->dccps_isr; 445 dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4); 446 } 447 448 static inline void dccp_update_gss(struct sock *sk, u64 seq) 449 { 450 struct dccp_sock *dp = dccp_sk(sk); 451 452 dp->dccps_gss = seq; 453 /* Ack validity window depends on local Sequence Window value (7.5.1) */ 454 dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win); 455 /* Adjust AWL so that it is not below ISS - see comment above for SWL */ 456 if (before48(dp->dccps_awl, dp->dccps_iss)) 457 dp->dccps_awl = dp->dccps_iss; 458 dp->dccps_awh = dp->dccps_gss; 459 } 460 461 static inline int dccp_ackvec_pending(const struct sock *sk) 462 { 463 return dccp_sk(sk)->dccps_hc_rx_ackvec != NULL && 464 !dccp_ackvec_is_empty(dccp_sk(sk)->dccps_hc_rx_ackvec); 465 } 466 467 static inline int dccp_ack_pending(const struct sock *sk) 468 { 469 return dccp_ackvec_pending(sk) || inet_csk_ack_scheduled(sk); 470 } 471 472 int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val); 473 int dccp_feat_finalise_settings(struct dccp_sock *dp); 474 int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq); 475 int dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*, 476 struct sk_buff *skb); 477 int dccp_feat_activate_values(struct sock *sk, struct list_head *fn); 478 void dccp_feat_list_purge(struct list_head *fn_list); 479 480 int dccp_insert_options(struct sock *sk, struct sk_buff *skb); 481 int dccp_insert_options_rsk(struct dccp_request_sock *, struct sk_buff *); 482 int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed); 483 u32 dccp_timestamp(void); 484 void dccp_timestamping_init(void); 485 int dccp_insert_option(struct sk_buff *skb, unsigned char option, 486 const void *value, unsigned char len); 487 488 #ifdef CONFIG_SYSCTL 489 int dccp_sysctl_init(void); 490 void dccp_sysctl_exit(void); 491 #else 492 static inline int dccp_sysctl_init(void) 493 { 494 return 0; 495 } 496 497 static inline void dccp_sysctl_exit(void) 498 { 499 } 500 #endif 501 502 #endif /* _DCCP_H */ 503