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, ...) \ 26 net_warn_ratelimited("%s: " fmt, __func__, ##__VA_ARGS__) 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 42extern 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 52extern struct inet_hashinfo dccp_hashinfo; 53 54extern struct percpu_counter dccp_orphan_count; 55 56void 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 */ 97extern int sysctl_dccp_request_retries; 98extern int sysctl_dccp_retries1; 99extern int sysctl_dccp_retries2; 100extern int sysctl_dccp_tx_qlen; 101extern 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 114static inline void dccp_set_seqno(u64 *seqno, u64 value) 115{ 116 *seqno = value & UINT48_MAX; 117} 118 119static 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 */ 125static 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 ? */ 133static 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 ? */ 142static 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 147static 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 */ 158static 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 */ 171static 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 176enum { 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 196struct dccp_mib { 197 unsigned long mibs[DCCP_MIB_MAX]; 198}; 199 200DECLARE_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 */ 208static 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 217static 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 227void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb); 228 229int dccp_retransmit_skb(struct sock *sk); 230 231void dccp_send_ack(struct sock *sk); 232void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, 233 struct request_sock *rsk); 234 235void 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 */ 241void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb); 242bool dccp_qpolicy_full(struct sock *sk); 243void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb); 244struct sk_buff *dccp_qpolicy_top(struct sock *sk); 245struct sk_buff *dccp_qpolicy_pop(struct sock *sk); 246bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param); 247 248/* 249 * TX Packet Output and TX Timers 250 */ 251void dccp_write_xmit(struct sock *sk); 252void dccp_write_space(struct sock *sk); 253void dccp_flush_write_queue(struct sock *sk, long *time_budget); 254 255void dccp_init_xmit_timers(struct sock *sk); 256static inline void dccp_clear_xmit_timers(struct sock *sk) 257{ 258 inet_csk_clear_xmit_timers(sk); 259} 260 261unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu); 262 263const char *dccp_packet_name(const int type); 264 265void dccp_set_state(struct sock *sk, const int state); 266void dccp_done(struct sock *sk); 267 268int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp, 269 struct sk_buff const *skb); 270 271int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb); 272 273struct sock *dccp_create_openreq_child(struct sock *sk, 274 const struct request_sock *req, 275 const struct sk_buff *skb); 276 277int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); 278 279struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb, 280 struct request_sock *req, 281 struct dst_entry *dst); 282struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, 283 struct request_sock *req); 284 285int dccp_child_process(struct sock *parent, struct sock *child, 286 struct sk_buff *skb); 287int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, 288 struct dccp_hdr *dh, unsigned int len); 289int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, 290 const struct dccp_hdr *dh, const unsigned int len); 291 292int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized); 293void dccp_destroy_sock(struct sock *sk); 294 295void dccp_close(struct sock *sk, long timeout); 296struct sk_buff *dccp_make_response(struct sock *sk, struct dst_entry *dst, 297 struct request_sock *req); 298 299int dccp_connect(struct sock *sk); 300int dccp_disconnect(struct sock *sk, int flags); 301int dccp_getsockopt(struct sock *sk, int level, int optname, 302 char __user *optval, int __user *optlen); 303int dccp_setsockopt(struct sock *sk, int level, int optname, 304 char __user *optval, unsigned int optlen); 305#ifdef CONFIG_COMPAT 306int compat_dccp_getsockopt(struct sock *sk, int level, int optname, 307 char __user *optval, int __user *optlen); 308int compat_dccp_setsockopt(struct sock *sk, int level, int optname, 309 char __user *optval, unsigned int optlen); 310#endif 311int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg); 312int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); 313int dccp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, 314 int flags, int *addr_len); 315void dccp_shutdown(struct sock *sk, int how); 316int inet_dccp_listen(struct socket *sock, int backlog); 317unsigned int dccp_poll(struct file *file, struct socket *sock, 318 poll_table *wait); 319int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); 320void dccp_req_err(struct sock *sk, u64 seq); 321 322struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *skb); 323int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code); 324void dccp_send_close(struct sock *sk, const int active); 325int dccp_invalid_packet(struct sk_buff *skb); 326u32 dccp_sample_rtt(struct sock *sk, long delta); 327 328static inline int dccp_bad_service_code(const struct sock *sk, 329 const __be32 service) 330{ 331 const struct dccp_sock *dp = dccp_sk(sk); 332 333 if (dp->dccps_service == service) 334 return 0; 335 return !dccp_list_has_service(dp->dccps_service_list, service); 336} 337 338/** 339 * dccp_skb_cb - DCCP per-packet control information 340 * @dccpd_type: one of %dccp_pkt_type (or unknown) 341 * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1 342 * @dccpd_reset_code: one of %dccp_reset_codes 343 * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code) 344 * @dccpd_opt_len: total length of all options (5.8) in the packet 345 * @dccpd_seq: sequence number 346 * @dccpd_ack_seq: acknowledgment number subheader field value 347 * 348 * This is used for transmission as well as for reception. 349 */ 350struct dccp_skb_cb { 351 union { 352 struct inet_skb_parm h4; 353#if IS_ENABLED(CONFIG_IPV6) 354 struct inet6_skb_parm h6; 355#endif 356 } header; 357 __u8 dccpd_type:4; 358 __u8 dccpd_ccval:4; 359 __u8 dccpd_reset_code, 360 dccpd_reset_data[3]; 361 __u16 dccpd_opt_len; 362 __u64 dccpd_seq; 363 __u64 dccpd_ack_seq; 364}; 365 366#define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0])) 367 368/* RFC 4340, sec. 7.7 */ 369static inline int dccp_non_data_packet(const struct sk_buff *skb) 370{ 371 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type; 372 373 return type == DCCP_PKT_ACK || 374 type == DCCP_PKT_CLOSE || 375 type == DCCP_PKT_CLOSEREQ || 376 type == DCCP_PKT_RESET || 377 type == DCCP_PKT_SYNC || 378 type == DCCP_PKT_SYNCACK; 379} 380 381/* RFC 4340, sec. 7.7 */ 382static inline int dccp_data_packet(const struct sk_buff *skb) 383{ 384 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type; 385 386 return type == DCCP_PKT_DATA || 387 type == DCCP_PKT_DATAACK || 388 type == DCCP_PKT_REQUEST || 389 type == DCCP_PKT_RESPONSE; 390} 391 392static inline int dccp_packet_without_ack(const struct sk_buff *skb) 393{ 394 const __u8 type = DCCP_SKB_CB(skb)->dccpd_type; 395 396 return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST; 397} 398 399#define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2) 400 401static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss) 402{ 403 struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh + 404 sizeof(*dh)); 405 dh->dccph_seq2 = 0; 406 dh->dccph_seq = htons((gss >> 32) & 0xfffff); 407 dhx->dccph_seq_low = htonl(gss & 0xffffffff); 408} 409 410static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack, 411 const u64 gsr) 412{ 413 dhack->dccph_reserved1 = 0; 414 dhack->dccph_ack_nr_high = htons(gsr >> 32); 415 dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff); 416} 417 418static inline void dccp_update_gsr(struct sock *sk, u64 seq) 419{ 420 struct dccp_sock *dp = dccp_sk(sk); 421 422 if (after48(seq, dp->dccps_gsr)) 423 dp->dccps_gsr = seq; 424 /* Sequence validity window depends on remote Sequence Window (7.5.1) */ 425 dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4); 426 /* 427 * Adjust SWL so that it is not below ISR. In contrast to RFC 4340, 428 * 7.5.1 we perform this check beyond the initial handshake: W/W' are 429 * always > 32, so for the first W/W' packets in the lifetime of a 430 * connection we always have to adjust SWL. 431 * A second reason why we are doing this is that the window depends on 432 * the feature-remote value of Sequence Window: nothing stops the peer 433 * from updating this value while we are busy adjusting SWL for the 434 * first W packets (we would have to count from scratch again then). 435 * Therefore it is safer to always make sure that the Sequence Window 436 * is not artificially extended by a peer who grows SWL downwards by 437 * continually updating the feature-remote Sequence-Window. 438 * If sequence numbers wrap it is bad luck. But that will take a while 439 * (48 bit), and this measure prevents Sequence-number attacks. 440 */ 441 if (before48(dp->dccps_swl, dp->dccps_isr)) 442 dp->dccps_swl = dp->dccps_isr; 443 dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4); 444} 445 446static inline void dccp_update_gss(struct sock *sk, u64 seq) 447{ 448 struct dccp_sock *dp = dccp_sk(sk); 449 450 dp->dccps_gss = seq; 451 /* Ack validity window depends on local Sequence Window value (7.5.1) */ 452 dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win); 453 /* Adjust AWL so that it is not below ISS - see comment above for SWL */ 454 if (before48(dp->dccps_awl, dp->dccps_iss)) 455 dp->dccps_awl = dp->dccps_iss; 456 dp->dccps_awh = dp->dccps_gss; 457} 458 459static inline int dccp_ackvec_pending(const struct sock *sk) 460{ 461 return dccp_sk(sk)->dccps_hc_rx_ackvec != NULL && 462 !dccp_ackvec_is_empty(dccp_sk(sk)->dccps_hc_rx_ackvec); 463} 464 465static inline int dccp_ack_pending(const struct sock *sk) 466{ 467 return dccp_ackvec_pending(sk) || inet_csk_ack_scheduled(sk); 468} 469 470int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val); 471int dccp_feat_finalise_settings(struct dccp_sock *dp); 472int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq); 473int dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*, 474 struct sk_buff *skb); 475int dccp_feat_activate_values(struct sock *sk, struct list_head *fn); 476void dccp_feat_list_purge(struct list_head *fn_list); 477 478int dccp_insert_options(struct sock *sk, struct sk_buff *skb); 479int dccp_insert_options_rsk(struct dccp_request_sock *, struct sk_buff *); 480u32 dccp_timestamp(void); 481void dccp_timestamping_init(void); 482int dccp_insert_option(struct sk_buff *skb, unsigned char option, 483 const void *value, unsigned char len); 484 485#ifdef CONFIG_SYSCTL 486int dccp_sysctl_init(void); 487void dccp_sysctl_exit(void); 488#else 489static inline int dccp_sysctl_init(void) 490{ 491 return 0; 492} 493 494static inline void dccp_sysctl_exit(void) 495{ 496} 497#endif 498 499#endif /* _DCCP_H */ 500