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  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   8  *
   9  *      This program is free software; you can redistribute it and/or modify it
  10  *      under the terms of the GNU General Public License version 2 as
  11  *      published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/dccp.h>
  15 #include <net/snmp.h>
  16 #include <net/sock.h>
  17 #include <net/tcp.h>
  18
  19 #define DCCP_DEBUG
  20
  21 #ifdef DCCP_DEBUG
  22 extern int dccp_debug;
  23
  24 #define dccp_pr_debug(format, a...) \
  25         do { if (dccp_debug) \
  26                 printk(KERN_DEBUG "%s: " format, __FUNCTION__ , ##a); \
  27         } while (0)
  28 #define dccp_pr_debug_cat(format, a...) do { if (dccp_debug) printk(format, ##a); } while (0)
  29 #else
  30 #define dccp_pr_debug(format, a...)
  31 #define dccp_pr_debug_cat(format, a...)
  32 #endif
  33
  34 extern struct inet_hashinfo dccp_hashinfo;
  35
  36 extern atomic_t dccp_orphan_count;
  37 extern int dccp_tw_count;
  38 extern void dccp_tw_deschedule(struct inet_timewait_sock *tw);
  39
  40 extern void dccp_time_wait(struct sock *sk, int state, int timeo);
  41
  42 /* FIXME: Right size this */
  43 #define DCCP_MAX_OPT_LEN 128
  44
  45 #define DCCP_MAX_PACKET_HDR 32
  46
  47 #define MAX_DCCP_HEADER  (DCCP_MAX_PACKET_HDR + DCCP_MAX_OPT_LEN + MAX_HEADER)
  48
  49 #define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
  50                                      * state, about 60 seconds */
  51
  52 /* draft-ietf-dccp-spec-11.txt initial RTO value */
  53 #define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
  54
  55 /* Maximal interval between probes for local resources.  */
  56 #define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))
  57
  58 #define DCCP_RTO_MAX ((unsigned)(120 * HZ)) /* FIXME: using TCP value */
  59
  60 extern struct proto dccp_v4_prot;
  61
  62 /* is seq1 < seq2 ? */
  63 static inline const  int before48(const u64 seq1, const u64 seq2)
  64 {
  65         return (const s64)((seq1 << 16) - (seq2 << 16)) < 0;
  66 }
  67
  68 /* is seq1 > seq2 ? */
  69 static inline const  int after48(const u64 seq1, const u64 seq2)
  70 {
  71         return (const s64)((seq2 << 16) - (seq1 << 16)) < 0;
  72 }
  73
  74 /* is seq2 <= seq1 <= seq3 ? */
  75 static inline const int between48(const u64 seq1, const u64 seq2, const u64 seq3)
  76 {
  77         return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
  78 }
  79
  80 static inline u64 max48(const u64 seq1, const u64 seq2)
  81 {
  82         return after48(seq1, seq2) ? seq1 : seq2;
  83 }
  84
  85 enum {
  86         DCCP_MIB_NUM = 0,
  87         DCCP_MIB_ACTIVEOPENS,                   /* ActiveOpens */
  88         DCCP_MIB_ESTABRESETS,                   /* EstabResets */
  89         DCCP_MIB_CURRESTAB,                     /* CurrEstab */
  90         DCCP_MIB_OUTSEGS,                       /* OutSegs */
  91         DCCP_MIB_OUTRSTS,
  92         DCCP_MIB_ABORTONTIMEOUT,
  93         DCCP_MIB_TIMEOUTS,
  94         DCCP_MIB_ABORTFAILED,
  95         DCCP_MIB_PASSIVEOPENS,
  96         DCCP_MIB_ATTEMPTFAILS,
  97         DCCP_MIB_OUTDATAGRAMS,
  98         DCCP_MIB_INERRS,
  99         DCCP_MIB_OPTMANDATORYERROR,
 100         DCCP_MIB_INVALIDOPT,
 101         __DCCP_MIB_MAX
 102 };
 103
 104 #define DCCP_MIB_MAX    __DCCP_MIB_MAX
 105 struct dccp_mib {
 106         unsigned long   mibs[DCCP_MIB_MAX];
 107 } __SNMP_MIB_ALIGN__;
 108
 109 DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
 110 #define DCCP_INC_STATS(field)           SNMP_INC_STATS(dccp_statistics, field)
 111 #define DCCP_INC_STATS_BH(field)        SNMP_INC_STATS_BH(dccp_statistics, field)
 112 #define DCCP_INC_STATS_USER(field)      SNMP_INC_STATS_USER(dccp_statistics, field)
 113 #define DCCP_DEC_STATS(field)           SNMP_DEC_STATS(dccp_statistics, field)
 114 #define DCCP_ADD_STATS_BH(field, val)   SNMP_ADD_STATS_BH(dccp_statistics, field, val)
 115 #define DCCP_ADD_STATS_USER(field, val) SNMP_ADD_STATS_USER(dccp_statistics, field, val)
 116
 117 extern int  dccp_transmit_skb(struct sock *sk, struct sk_buff *skb);
 118 extern int  dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);
 119
 120 extern int dccp_send_response(struct sock *sk);
 121 extern void dccp_send_ack(struct sock *sk);
 122 extern void dccp_send_delayed_ack(struct sock *sk);
 123 extern void dccp_send_sync(struct sock *sk, u64 seq);
 124
 125 extern void dccp_init_xmit_timers(struct sock *sk);
 126 static inline void dccp_clear_xmit_timers(struct sock *sk)
 127 {
 128         inet_csk_clear_xmit_timers(sk);
 129 }
 130
 131 extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
 132
 133 extern const char *dccp_packet_name(const int type);
 134 extern const char *dccp_state_name(const int state);
 135
 136 static inline void dccp_set_state(struct sock *sk, const int state)
 137 {
 138         const int oldstate = sk->sk_state;
 139
 140         dccp_pr_debug("%s(%p) %-10.10s -> %s\n",
 141                       dccp_role(sk), sk,
 142                       dccp_state_name(oldstate), dccp_state_name(state));
 143         WARN_ON(state == oldstate);
 144
 145         switch (state) {
 146         case DCCP_OPEN:
 147                 if (oldstate != DCCP_OPEN)
 148                         DCCP_INC_STATS(DCCP_MIB_CURRESTAB);
 149                 break;
 150
 151         case DCCP_CLOSED:
 152                 if (oldstate == DCCP_CLOSING || oldstate == DCCP_OPEN)
 153                         DCCP_INC_STATS(DCCP_MIB_ESTABRESETS);
 154
 155                 sk->sk_prot->unhash(sk);
 156                 if (inet_csk(sk)->icsk_bind_hash != NULL &&
 157                     !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
 158                         inet_put_port(&dccp_hashinfo, sk);
 159                 /* fall through */
 160         default:
 161                 if (oldstate == DCCP_OPEN)
 162                         DCCP_DEC_STATS(DCCP_MIB_CURRESTAB);
 163         }
 164
 165         /* Change state AFTER socket is unhashed to avoid closed
 166          * socket sitting in hash tables.
 167          */
 168         sk->sk_state = state;
 169 }
 170
 171 static inline void dccp_done(struct sock *sk)
 172 {
 173         dccp_set_state(sk, DCCP_CLOSED);
 174         dccp_clear_xmit_timers(sk);
 175
 176         sk->sk_shutdown = SHUTDOWN_MASK;
 177
 178         if (!sock_flag(sk, SOCK_DEAD))
 179                 sk->sk_state_change(sk);
 180         else
 181                 inet_csk_destroy_sock(sk);
 182 }
 183
 184 static inline void dccp_openreq_init(struct request_sock *req,
 185                                      struct dccp_sock *dp,
 186                                      struct sk_buff *skb)
 187 {
 188         /*
 189          * FIXME: fill in the other req fields from the DCCP options
 190          * received
 191          */
 192         inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
 193         inet_rsk(req)->acked    = 0;
 194         req->rcv_wnd = 0;
 195 }
 196
 197 extern void dccp_v4_send_check(struct sock *sk, struct dccp_hdr *dh, int len,
 198                                struct sk_buff *skb);
 199 extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
 200
 201 extern struct sock *dccp_create_openreq_child(struct sock *sk,
 202                                               const struct request_sock *req,
 203                                               const struct sk_buff *skb);
 204
 205 extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
 206
 207 extern void dccp_v4_err(struct sk_buff *skb, u32);
 208
 209 extern int dccp_v4_rcv(struct sk_buff *skb);
 210
 211 extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
 212                                               struct sk_buff *skb,
 213                                               struct request_sock *req,
 214                                               struct dst_entry *dst);
 215 extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
 216                                    struct request_sock *req,
 217                                    struct request_sock **prev);
 218
 219 extern int dccp_child_process(struct sock *parent, struct sock *child,
 220                               struct sk_buff *skb);
 221 extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 222                                   struct dccp_hdr *dh, unsigned len);
 223 extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
 224                                 const struct dccp_hdr *dh, const unsigned len);
 225
 226 extern void             dccp_close(struct sock *sk, long timeout);
 227 extern struct sk_buff   *dccp_make_response(struct sock *sk,
 228                                             struct dst_entry *dst,
 229                                             struct request_sock *req);
 230
 231 extern int         dccp_connect(struct sock *sk);
 232 extern int         dccp_disconnect(struct sock *sk, int flags);
 233 extern int         dccp_getsockopt(struct sock *sk, int level, int optname,
 234                                    char *optval, int *optlen);
 235 extern int         dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 236 extern int         dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 237                                 size_t size);
 238 extern int         dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
 239                                 struct msghdr *msg, size_t len, int nonblock,
 240                                 int flags, int *addr_len);
 241 extern int         dccp_setsockopt(struct sock *sk, int level, int optname,
 242                                    char *optval, int optlen);
 243 extern void        dccp_shutdown(struct sock *sk, int how);
 244
 245 extern int         dccp_v4_checksum(const struct sk_buff *skb,
 246                                     const u32 saddr, const u32 daddr);
 247
 248 extern int         dccp_v4_send_reset(struct sock *sk, enum dccp_reset_codes code);
 249 extern void        dccp_send_close(struct sock *sk);
 250
 251 struct dccp_skb_cb {
 252         __u8 dccpd_type;
 253         __u8 dccpd_reset_code;
 254         __u8 dccpd_service;
 255         __u8 dccpd_ccval;
 256         __u64 dccpd_seq;
 257         __u64 dccpd_ack_seq;
 258         int  dccpd_opt_len;
 259 };
 260
 261 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
 262
 263 static inline int dccp_non_data_packet(const struct sk_buff *skb)
 264 {
 265         const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
 266
 267         return type == DCCP_PKT_ACK      ||
 268                type == DCCP_PKT_CLOSE    ||
 269                type == DCCP_PKT_CLOSEREQ ||
 270                type == DCCP_PKT_RESET    ||
 271                type == DCCP_PKT_SYNC     ||
 272                type == DCCP_PKT_SYNCACK;
 273 }
 274
 275 static inline int dccp_packet_without_ack(const struct sk_buff *skb)
 276 {
 277         const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
 278
 279         return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
 280 }
 281
 282 #define DCCP_MAX_SEQNO ((((u64)1) << 48) - 1)
 283 #define DCCP_PKT_WITHOUT_ACK_SEQ (DCCP_MAX_SEQNO << 2)
 284
 285 static inline void dccp_set_seqno(u64 *seqno, u64 value)
 286 {
 287         if (value > DCCP_MAX_SEQNO)
 288                 value -= DCCP_MAX_SEQNO + 1;
 289         *seqno = value;
 290 }
 291
 292 static inline u64 dccp_delta_seqno(u64 seqno1, u64 seqno2)
 293 {
 294         return ((seqno2 << 16) - (seqno1 << 16)) >> 16;
 295 }
 296
 297 static inline void dccp_inc_seqno(u64 *seqno)
 298 {
 299         if (++*seqno > DCCP_MAX_SEQNO)
 300                 *seqno = 0;
 301 }
 302
 303 static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
 304 {
 305         struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh + sizeof(*dh));
 306
 307 #if defined(__LITTLE_ENDIAN_BITFIELD)
 308         dh->dccph_seq      = htonl((gss >> 32)) >> 8;
 309 #elif defined(__BIG_ENDIAN_BITFIELD)
 310         dh->dccph_seq      = htonl((gss >> 32));
 311 #else
 312 #error  "Adjust your <asm/byteorder.h> defines"
 313 #endif
 314         dhx->dccph_seq_low = htonl(gss & 0xffffffff);
 315 }
 316
 317 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack, const u64 gsr)
 318 {
 319 #if defined(__LITTLE_ENDIAN_BITFIELD)
 320         dhack->dccph_ack_nr_high = htonl((gsr >> 32)) >> 8;
 321 #elif defined(__BIG_ENDIAN_BITFIELD)
 322         dhack->dccph_ack_nr_high = htonl((gsr >> 32));
 323 #else
 324 #error  "Adjust your <asm/byteorder.h> defines"
 325 #endif
 326         dhack->dccph_ack_nr_low  = htonl(gsr & 0xffffffff);
 327 }
 328
 329 static inline void dccp_update_gsr(struct sock *sk, u64 seq)
 330 {
 331         struct dccp_sock *dp = dccp_sk(sk);
 332         u64 tmp_gsr;
 333
 334         dccp_set_seqno(&tmp_gsr, dp->dccps_gsr + 1 - (dp->dccps_options.dccpo_sequence_window / 4));
 335         dp->dccps_gsr = seq;
 336         dccp_set_seqno(&dp->dccps_swl, max48(tmp_gsr, dp->dccps_isr));
 337         dccp_set_seqno(&dp->dccps_swh,
 338                        dp->dccps_gsr + (3 * dp->dccps_options.dccpo_sequence_window) / 4);
 339 }
 340
 341 static inline void dccp_update_gss(struct sock *sk, u64 seq)
 342 {
 343         struct dccp_sock *dp = dccp_sk(sk);
 344         u64 tmp_gss;
 345
 346         dccp_set_seqno(&tmp_gss, dp->dccps_gss - dp->dccps_options.dccpo_sequence_window + 1);
 347         dp->dccps_awl = max48(tmp_gss, dp->dccps_iss);
 348         dp->dccps_awh = dp->dccps_gss = seq;
 349 }
 350
 351 extern void dccp_insert_options(struct sock *sk, struct sk_buff *skb);
 352 extern void dccp_insert_option_elapsed_time(struct sock *sk,
 353                                             struct sk_buff *skb,
 354                                             u32 elapsed_time);
 355 extern void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
 356                                unsigned char option,
 357                                const void *value, unsigned char len);
 358
 359 extern struct socket *dccp_ctl_socket;
 360
 361 #define DCCP_ACKPKTS_STATE_RECEIVED     0
 362 #define DCCP_ACKPKTS_STATE_ECN_MARKED   (1 << 6)
 363 #define DCCP_ACKPKTS_STATE_NOT_RECEIVED (3 << 6)
 364
 365 #define DCCP_ACKPKTS_STATE_MASK         0xC0 /* 11000000 */
 366 #define DCCP_ACKPKTS_LEN_MASK           0x3F /* 00111111 */
 367
 368 /** struct dccp_ackpkts - acknowledgeable packets
 369  *
 370  * This data structure is the one defined in the DCCP draft
 371  * Appendix A.
 372  *
 373  * @dccpap_buf_head - circular buffer head
 374  * @dccpap_buf_tail - circular buffer tail
 375  * @dccpap_buf_ackno - ack # of the most recent packet acknoldgeable in the buffer (i.e. %dccpap_buf_head)
 376  * @dccpap_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked by the buffer with State 0
 377  *
 378  * Additionally, the HC-Receiver must keep some information about the
 379  * Ack Vectors it has recently sent. For each packet sent carrying an
 380  * Ack Vector, it remembers four variables:
 381  *
 382  * @dccpap_ack_seqno - the Sequence Number used for the packet (HC-Receiver seqno)
 383  * @dccpap_ack_ptr - the value of buf_head at the time of acknowledgement.
 384  * @dccpap_ack_ackno - the Acknowledgement Number used for the packet (HC-Sender seqno)
 385  * @dccpap_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
 386  *
 387  * @dccpap_buf_len - circular buffer length
 388  * @dccpap_buf - circular buffer of acknowledgeable packets
 389  */
 390 struct dccp_ackpkts {
 391         unsigned int            dccpap_buf_head;
 392         unsigned int            dccpap_buf_tail;
 393         u64                     dccpap_buf_ackno;
 394         u64                     dccpap_ack_seqno;
 395         u64                     dccpap_ack_ackno;
 396         unsigned int            dccpap_ack_ptr;
 397         unsigned int            dccpap_buf_vector_len;
 398         unsigned int            dccpap_ack_vector_len;
 399         unsigned int            dccpap_buf_len;
 400         unsigned long           dccpap_time;
 401         u8                      dccpap_buf_nonce;
 402         u8                      dccpap_ack_nonce;
 403         u8                      dccpap_buf[0];
 404 };
 405
 406 extern struct dccp_ackpkts *dccp_ackpkts_alloc(unsigned int len, int priority);
 407 extern void dccp_ackpkts_free(struct dccp_ackpkts *ap);
 408 extern int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state);
 409 extern void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap,
 410                                          struct sock *sk, u64 ackno);
 411
 412 #ifdef DCCP_DEBUG
 413 extern void dccp_ackvector_print(const u64 ackno,
 414                                  const unsigned char *vector, int len);
 415 extern void dccp_ackpkts_print(const struct dccp_ackpkts *ap);
 416 #else
 417 static inline void dccp_ackvector_print(const u64 ackno,
 418                                         const unsigned char *vector,
 419                                         int len) { }
 420 static inline void dccp_ackpkts_print(const struct dccp_ackpkts *ap) { }
 421 #endif
 422
 423 #endif /* _DCCP_H */