net/dccp/dccp.h

   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 int 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 #else
  46 #define dccp_pr_debug(format, a...)
  47 #define dccp_pr_debug_cat(format, a...)
  48 #endif
  49
  50 extern struct inet_hashinfo dccp_hashinfo;
  51
  52 extern atomic_t dccp_orphan_count;
  53
  54 extern void dccp_time_wait(struct sock *sk, int state, int timeo);
  55
  56 /*
  57  *  Set safe upper bounds for header and option length. Since Data Offset is 8
  58  *  bits (RFC 4340, sec. 5.1), the total header length can never be more than
  59  *  4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1):
  60  *    - DCCP-Response with ACK Subheader and 4 bytes of Service code      OR
  61  *    - DCCP-Reset    with ACK Subheader and 4 bytes of Reset Code fields
  62  *  Hence a safe upper bound for the maximum option length is 1020-28 = 992
  63  */
  64 #define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(int))
  65 #define DCCP_MAX_PACKET_HDR 28
  66 #define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR)
  67 #define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER)
  68
  69 #define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
  70                                      * state, about 60 seconds */
  71
  72 /* RFC 1122, 4.2.3.1 initial RTO value */
  73 #define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
  74
  75 /*
  76  * The maximum back-off value for retransmissions. This is needed for
  77  *  - retransmitting client-Requests (sec. 8.1.1),
  78  *  - retransmitting Close/CloseReq when closing (sec. 8.3),
  79  *  - feature-negotiation retransmission (sec. 6.6.3),
  80  *  - Acks in client-PARTOPEN state (sec. 8.1.5).
  81  */
  82 #define DCCP_RTO_MAX ((unsigned)(64 * HZ))
  83
  84 /*
  85  * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4
  86  */
  87 #define DCCP_SANE_RTT_MIN       100
  88 #define DCCP_FALLBACK_RTT       (USEC_PER_SEC / 5)
  89 #define DCCP_SANE_RTT_MAX       (3 * USEC_PER_SEC)
  90
  91 /* Maximal interval between probes for local resources.  */
  92 #define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))
  93
  94 /* sysctl variables for DCCP */
  95 extern int  sysctl_dccp_request_retries;
  96 extern int  sysctl_dccp_retries1;
  97 extern int  sysctl_dccp_retries2;
  98 extern int  sysctl_dccp_feat_sequence_window;
  99 extern int  sysctl_dccp_feat_rx_ccid;
 100 extern int  sysctl_dccp_feat_tx_ccid;
 101 extern int  sysctl_dccp_feat_ack_ratio;
 102 extern int  sysctl_dccp_feat_send_ack_vector;
 103 extern int  sysctl_dccp_feat_send_ndp_count;
 104 extern int  sysctl_dccp_tx_qlen;
 105 extern int  sysctl_dccp_sync_ratelimit;
 106
 107 /*
 108  *      48-bit sequence number arithmetic (signed and unsigned)
 109  */
 110 #define INT48_MIN         0x800000000000LL              /* 2^47     */
 111 #define UINT48_MAX        0xFFFFFFFFFFFFLL              /* 2^48 - 1 */
 112 #define COMPLEMENT48(x)  (0x1000000000000LL - (x))      /* 2^48 - x */
 113 #define TO_SIGNED48(x)   (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
 114 #define TO_UNSIGNED48(x) (((x) >= 0)?        (x) :  COMPLEMENT48(-(x)))
 115 #define ADD48(a, b)      (((a) + (b)) & UINT48_MAX)
 116 #define SUB48(a, b)      ADD48((a), COMPLEMENT48(b))
 117
 118 static inline void dccp_set_seqno(u64 *seqno, u64 value)
 119 {
 120         *seqno = value & UINT48_MAX;
 121 }
 122
 123 static inline void dccp_inc_seqno(u64 *seqno)
 124 {
 125         *seqno = ADD48(*seqno, 1);
 126 }
 127
 128 /* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
 129 static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
 130 {
 131         u64 delta = SUB48(seqno2, seqno1);
 132
 133         return TO_SIGNED48(delta);
 134 }
 135
 136 /* is seq1 < seq2 ? */
 137 static inline int before48(const u64 seq1, const u64 seq2)
 138 {
 139         return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
 140 }
 141
 142 /* is seq1 > seq2 ? */
 143 #define after48(seq1, seq2)     before48(seq2, seq1)
 144
 145 /* is seq2 <= seq1 <= seq3 ? */
 146 static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
 147 {
 148         return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
 149 }
 150
 151 static inline u64 max48(const u64 seq1, const u64 seq2)
 152 {
 153         return after48(seq1, seq2) ? seq1 : seq2;
 154 }
 155
 156 /**
 157  * dccp_loss_free  -  Evaluates condition for data loss from RFC 4340, 7.7.1
 158  * @s1:  start sequence number
 159  * @s2:  end sequence number
 160  * @ndp: NDP count on packet with sequence number @s2
 161  * Returns true if the sequence range s1...s2 has no data loss.
 162  */
 163 static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
 164 {
 165         s64 delta = dccp_delta_seqno(s1, s2);
 166
 167         WARN_ON(delta < 0);
 168         return (u64)delta <= ndp + 1;
 169 }
 170
 171 enum {
 172         DCCP_MIB_NUM = 0,
 173         DCCP_MIB_ACTIVEOPENS,                   /* ActiveOpens */
 174         DCCP_MIB_ESTABRESETS,                   /* EstabResets */
 175         DCCP_MIB_CURRESTAB,                     /* CurrEstab */
 176         DCCP_MIB_OUTSEGS,                       /* OutSegs */
 177         DCCP_MIB_OUTRSTS,
 178         DCCP_MIB_ABORTONTIMEOUT,
 179         DCCP_MIB_TIMEOUTS,
 180         DCCP_MIB_ABORTFAILED,
 181         DCCP_MIB_PASSIVEOPENS,
 182         DCCP_MIB_ATTEMPTFAILS,
 183         DCCP_MIB_OUTDATAGRAMS,
 184         DCCP_MIB_INERRS,
 185         DCCP_MIB_OPTMANDATORYERROR,
 186         DCCP_MIB_INVALIDOPT,
 187         __DCCP_MIB_MAX
 188 };
 189
 190 #define DCCP_MIB_MAX    __DCCP_MIB_MAX
 191 struct dccp_mib {
 192         unsigned long   mibs[DCCP_MIB_MAX];
 193 } __SNMP_MIB_ALIGN__;
 194
 195 DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
 196 #define DCCP_INC_STATS(field)       SNMP_INC_STATS(dccp_statistics, field)
 197 #define DCCP_INC_STATS_BH(field)    SNMP_INC_STATS_BH(dccp_statistics, field)
 198 #define DCCP_INC_STATS_USER(field)  SNMP_INC_STATS_USER(dccp_statistics, field)
 199 #define DCCP_DEC_STATS(field)       SNMP_DEC_STATS(dccp_statistics, field)
 200 #define DCCP_ADD_STATS_BH(field, val) \
 201                         SNMP_ADD_STATS_BH(dccp_statistics, field, val)
 202 #define DCCP_ADD_STATS_USER(field, val) \
 203                         SNMP_ADD_STATS_USER(dccp_statistics, field, val)
 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 extern void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
 228
 229 extern int  dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);
 230
 231 extern void dccp_send_ack(struct sock *sk);
 232 extern void dccp_reqsk_send_ack(struct sk_buff *sk, struct request_sock *rsk);
 233
 234 extern void dccp_send_sync(struct sock *sk, const u64 seq,
 235                            const enum dccp_pkt_type pkt_type);
 236
 237 extern void dccp_write_xmit(struct sock *sk, int block);
 238 extern void dccp_write_space(struct sock *sk);
 239
 240 extern void dccp_init_xmit_timers(struct sock *sk);
 241 static inline void dccp_clear_xmit_timers(struct sock *sk)
 242 {
 243         inet_csk_clear_xmit_timers(sk);
 244 }
 245
 246 extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
 247
 248 extern const char *dccp_packet_name(const int type);
 249 extern const char *dccp_state_name(const int state);
 250
 251 extern void dccp_set_state(struct sock *sk, const int state);
 252 extern void dccp_done(struct sock *sk);
 253
 254 extern void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb);
 255
 256 extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
 257
 258 extern struct sock *dccp_create_openreq_child(struct sock *sk,
 259                                               const struct request_sock *req,
 260                                               const struct sk_buff *skb);
 261
 262 extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
 263
 264 extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
 265                                               struct sk_buff *skb,
 266                                               struct request_sock *req,
 267                                               struct dst_entry *dst);
 268 extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
 269                                    struct request_sock *req,
 270                                    struct request_sock **prev);
 271
 272 extern int dccp_child_process(struct sock *parent, struct sock *child,
 273                               struct sk_buff *skb);
 274 extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 275                                   struct dccp_hdr *dh, unsigned len);
 276 extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
 277                                 const struct dccp_hdr *dh, const unsigned len);
 278
 279 extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
 280 extern void dccp_destroy_sock(struct sock *sk);
 281
 282 extern void             dccp_close(struct sock *sk, long timeout);
 283 extern struct sk_buff   *dccp_make_response(struct sock *sk,
 284                                             struct dst_entry *dst,
 285                                             struct request_sock *req);
 286
 287 extern int         dccp_connect(struct sock *sk);
 288 extern int         dccp_disconnect(struct sock *sk, int flags);
 289 extern int         dccp_getsockopt(struct sock *sk, int level, int optname,
 290                                    char __user *optval, int __user *optlen);
 291 extern int         dccp_setsockopt(struct sock *sk, int level, int optname,
 292                                    char __user *optval, int optlen);
 293 #ifdef CONFIG_COMPAT
 294 extern int         compat_dccp_getsockopt(struct sock *sk,
 295                                 int level, int optname,
 296                                 char __user *optval, int __user *optlen);
 297 extern int         compat_dccp_setsockopt(struct sock *sk,
 298                                 int level, int optname,
 299                                 char __user *optval, int optlen);
 300 #endif
 301 extern int         dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 302 extern int         dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
 303                                 struct msghdr *msg, size_t size);
 304 extern int         dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
 305                                 struct msghdr *msg, size_t len, int nonblock,
 306                                 int flags, int *addr_len);
 307 extern void        dccp_shutdown(struct sock *sk, int how);
 308 extern int         inet_dccp_listen(struct socket *sock, int backlog);
 309 extern unsigned int dccp_poll(struct file *file, struct socket *sock,
 310                              poll_table *wait);
 311 extern int         dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
 312                                    int addr_len);
 313
 314 extern struct sk_buff *dccp_ctl_make_reset(struct sock *sk,
 315                                            struct sk_buff *skb);
 316 extern int         dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
 317 extern void        dccp_send_close(struct sock *sk, const int active);
 318 extern int         dccp_invalid_packet(struct sk_buff *skb);
 319 extern u32         dccp_sample_rtt(struct sock *sk, long delta);
 320
 321 static inline int dccp_bad_service_code(const struct sock *sk,
 322                                         const __be32 service)
 323 {
 324         const struct dccp_sock *dp = dccp_sk(sk);
 325
 326         if (dp->dccps_service == service)
 327                 return 0;
 328         return !dccp_list_has_service(dp->dccps_service_list, service);
 329 }
 330
 331 /**
 332  * dccp_skb_cb  -  DCCP per-packet control information
 333  * @dccpd_type: one of %dccp_pkt_type (or unknown)
 334  * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1
 335  * @dccpd_reset_code: one of %dccp_reset_codes
 336  * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code)
 337  * @dccpd_opt_len: total length of all options (5.8) in the packet
 338  * @dccpd_seq: sequence number
 339  * @dccpd_ack_seq: acknowledgment number subheader field value
 340  * This is used for transmission as well as for reception.
 341  */
 342 struct dccp_skb_cb {
 343         union {
 344                 struct inet_skb_parm    h4;
 345 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
 346                 struct inet6_skb_parm   h6;
 347 #endif
 348         } header;
 349         __u8  dccpd_type:4;
 350         __u8  dccpd_ccval:4;
 351         __u8  dccpd_reset_code,
 352               dccpd_reset_data[3];
 353         __u16 dccpd_opt_len;
 354         __u64 dccpd_seq;
 355         __u64 dccpd_ack_seq;
 356 };
 357
 358 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
 359
 360 /* RFC 4340, sec. 7.7 */
 361 static inline int dccp_non_data_packet(const struct sk_buff *skb)
 362 {
 363         const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
 364
 365         return type == DCCP_PKT_ACK      ||
 366                type == DCCP_PKT_CLOSE    ||
 367                type == DCCP_PKT_CLOSEREQ ||
 368                type == DCCP_PKT_RESET    ||
 369                type == DCCP_PKT_SYNC     ||
 370                type == DCCP_PKT_SYNCACK;
 371 }
 372
 373 /* RFC 4340, sec. 7.7 */
 374 static inline int dccp_data_packet(const struct sk_buff *skb)
 375 {
 376         const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
 377
 378         return type == DCCP_PKT_DATA     ||
 379                type == DCCP_PKT_DATAACK  ||
 380                type == DCCP_PKT_REQUEST  ||
 381                type == DCCP_PKT_RESPONSE;
 382 }
 383
 384 static inline int dccp_packet_without_ack(const struct sk_buff *skb)
 385 {
 386         const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
 387
 388         return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
 389 }
 390
 391 #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
 392
 393 static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
 394 {
 395         struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
 396                                                            sizeof(*dh));
 397         dh->dccph_seq2 = 0;
 398         dh->dccph_seq = htons((gss >> 32) & 0xfffff);
 399         dhx->dccph_seq_low = htonl(gss & 0xffffffff);
 400 }
 401
 402 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
 403                                     const u64 gsr)
 404 {
 405         dhack->dccph_reserved1 = 0;
 406         dhack->dccph_ack_nr_high = htons(gsr >> 32);
 407         dhack->dccph_ack_nr_low  = htonl(gsr & 0xffffffff);
 408 }
 409
 410 static inline void dccp_update_gsr(struct sock *sk, u64 seq)
 411 {
 412         struct dccp_sock *dp = dccp_sk(sk);
 413         const struct dccp_minisock *dmsk = dccp_msk(sk);
 414
 415         dp->dccps_gsr = seq;
 416         dccp_set_seqno(&dp->dccps_swl,
 417                        dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4));
 418         dccp_set_seqno(&dp->dccps_swh,
 419                        dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4);
 420 }
 421
 422 static inline void dccp_update_gss(struct sock *sk, u64 seq)
 423 {
 424         struct dccp_sock *dp = dccp_sk(sk);
 425
 426         dp->dccps_awh = dp->dccps_gss = seq;
 427         dccp_set_seqno(&dp->dccps_awl,
 428                        (dp->dccps_gss -
 429                         dccp_msk(sk)->dccpms_sequence_window + 1));
 430 }
 431
 432 static inline int dccp_ack_pending(const struct sock *sk)
 433 {
 434         const struct dccp_sock *dp = dccp_sk(sk);
 435         return dp->dccps_timestamp_echo != 0 ||
 436 #ifdef CONFIG_IP_DCCP_ACKVEC
 437                (dccp_msk(sk)->dccpms_send_ack_vector &&
 438                 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
 439 #endif
 440                inet_csk_ack_scheduled(sk);
 441 }
 442
 443 extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
 444 extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
 445 extern int dccp_insert_option_elapsed_time(struct sock *sk,
 446                                             struct sk_buff *skb,
 447                                             u32 elapsed_time);
 448 extern u32 dccp_timestamp(void);
 449 extern void dccp_timestamping_init(void);
 450 extern int dccp_insert_option_timestamp(struct sock *sk,
 451                                          struct sk_buff *skb);
 452 extern int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
 453                                unsigned char option,
 454                                const void *value, unsigned char len);
 455
 456 #ifdef CONFIG_SYSCTL
 457 extern int dccp_sysctl_init(void);
 458 extern void dccp_sysctl_exit(void);
 459 #else
 460 static inline int dccp_sysctl_init(void)
 461 {
 462         return 0;
 463 }
 464
 465 static inline void dccp_sysctl_exit(void)
 466 {
 467 }
 468 #endif
 469
 470 #endif /* _DCCP_H */