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                                                         __FUNCTION__, ##a)
  27 #define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \
  28                                          __FILE__, __LINE__, __FUNCTION__)
  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, __FUNCTION__, ##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 #define DCCP_RTO_MAX ((unsigned)(120 * HZ)) /* FIXME: using TCP value */
  76
  77 /* bounds for sampled RTT values from packet exchanges (in usec) */
  78 #define DCCP_SANE_RTT_MIN       100
  79 #define DCCP_SANE_RTT_MAX       (4 * USEC_PER_SEC)
  80
  81 /* Maximal interval between probes for local resources.  */
  82 #define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))
  83
  84 /* sysctl variables for DCCP */
  85 extern int  sysctl_dccp_request_retries;
  86 extern int  sysctl_dccp_retries1;
  87 extern int  sysctl_dccp_retries2;
  88 extern int  sysctl_dccp_feat_sequence_window;
  89 extern int  sysctl_dccp_feat_rx_ccid;
  90 extern int  sysctl_dccp_feat_tx_ccid;
  91 extern int  sysctl_dccp_feat_ack_ratio;
  92 extern int  sysctl_dccp_feat_send_ack_vector;
  93 extern int  sysctl_dccp_feat_send_ndp_count;
  94 extern int  sysctl_dccp_tx_qlen;
  95
  96 /*
  97  *      48-bit sequence number arithmetic (signed and unsigned)
  98  */
  99 #define INT48_MIN         0x800000000000LL              /* 2^47     */
 100 #define UINT48_MAX        0xFFFFFFFFFFFFLL              /* 2^48 - 1 */
 101 #define COMPLEMENT48(x)  (0x1000000000000LL - (x))      /* 2^48 - x */
 102 #define TO_SIGNED48(x)   (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x)))
 103 #define TO_UNSIGNED48(x) (((x) >= 0)?        (x) :  COMPLEMENT48(-(x)))
 104 #define ADD48(a, b)      (((a) + (b)) & UINT48_MAX)
 105 #define SUB48(a, b)      ADD48((a), COMPLEMENT48(b))
 106
 107 static inline void dccp_set_seqno(u64 *seqno, u64 value)
 108 {
 109         *seqno = value & UINT48_MAX;
 110 }
 111
 112 static inline void dccp_inc_seqno(u64 *seqno)
 113 {
 114         *seqno = ADD48(*seqno, 1);
 115 }
 116
 117 /* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */
 118 static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2)
 119 {
 120         u64 delta = SUB48(seqno2, seqno1);
 121
 122         return TO_SIGNED48(delta);
 123 }
 124
 125 /* is seq1 < seq2 ? */
 126 static inline int before48(const u64 seq1, const u64 seq2)
 127 {
 128         return (s64)((seq2 << 16) - (seq1 << 16)) > 0;
 129 }
 130
 131 /* is seq1 > seq2 ? */
 132 #define after48(seq1, seq2)     before48(seq2, seq1)
 133
 134 /* is seq2 <= seq1 <= seq3 ? */
 135 static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3)
 136 {
 137         return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16);
 138 }
 139
 140 static inline u64 max48(const u64 seq1, const u64 seq2)
 141 {
 142         return after48(seq1, seq2) ? seq1 : seq2;
 143 }
 144
 145 /* is seq1 next seqno after seq2 */
 146 static inline int follows48(const u64 seq1, const u64 seq2)
 147 {
 148         return dccp_delta_seqno(seq2, seq1) == 1;
 149 }
 150
 151 enum {
 152         DCCP_MIB_NUM = 0,
 153         DCCP_MIB_ACTIVEOPENS,                   /* ActiveOpens */
 154         DCCP_MIB_ESTABRESETS,                   /* EstabResets */
 155         DCCP_MIB_CURRESTAB,                     /* CurrEstab */
 156         DCCP_MIB_OUTSEGS,                       /* OutSegs */
 157         DCCP_MIB_OUTRSTS,
 158         DCCP_MIB_ABORTONTIMEOUT,
 159         DCCP_MIB_TIMEOUTS,
 160         DCCP_MIB_ABORTFAILED,
 161         DCCP_MIB_PASSIVEOPENS,
 162         DCCP_MIB_ATTEMPTFAILS,
 163         DCCP_MIB_OUTDATAGRAMS,
 164         DCCP_MIB_INERRS,
 165         DCCP_MIB_OPTMANDATORYERROR,
 166         DCCP_MIB_INVALIDOPT,
 167         __DCCP_MIB_MAX
 168 };
 169
 170 #define DCCP_MIB_MAX    __DCCP_MIB_MAX
 171 struct dccp_mib {
 172         unsigned long   mibs[DCCP_MIB_MAX];
 173 } __SNMP_MIB_ALIGN__;
 174
 175 DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
 176 #define DCCP_INC_STATS(field)       SNMP_INC_STATS(dccp_statistics, field)
 177 #define DCCP_INC_STATS_BH(field)    SNMP_INC_STATS_BH(dccp_statistics, field)
 178 #define DCCP_INC_STATS_USER(field)  SNMP_INC_STATS_USER(dccp_statistics, field)
 179 #define DCCP_DEC_STATS(field)       SNMP_DEC_STATS(dccp_statistics, field)
 180 #define DCCP_ADD_STATS_BH(field, val) \
 181                         SNMP_ADD_STATS_BH(dccp_statistics, field, val)
 182 #define DCCP_ADD_STATS_USER(field, val) \
 183                         SNMP_ADD_STATS_USER(dccp_statistics, field, val)
 184
 185 /*
 186  *      Checksumming routines
 187  */
 188 static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb)
 189 {
 190         const struct dccp_hdr* dh = dccp_hdr(skb);
 191
 192         if (dh->dccph_cscov == 0)
 193                 return skb->len;
 194         return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32);
 195 }
 196
 197 static inline void dccp_csum_outgoing(struct sk_buff *skb)
 198 {
 199         unsigned int cov = dccp_csum_coverage(skb);
 200
 201         if (cov >= skb->len)
 202                 dccp_hdr(skb)->dccph_cscov = 0;
 203
 204         skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0);
 205 }
 206
 207 extern void dccp_v4_send_check(struct sock *sk, int len, struct sk_buff *skb);
 208
 209 extern int  dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);
 210
 211 extern void dccp_send_ack(struct sock *sk);
 212 extern void dccp_send_delayed_ack(struct sock *sk);
 213 extern void dccp_reqsk_send_ack(struct sk_buff *sk, struct request_sock *rsk);
 214
 215 extern void dccp_send_sync(struct sock *sk, const u64 seq,
 216                            const enum dccp_pkt_type pkt_type);
 217
 218 extern void dccp_write_xmit(struct sock *sk, int block);
 219 extern void dccp_write_space(struct sock *sk);
 220
 221 extern void dccp_init_xmit_timers(struct sock *sk);
 222 static inline void dccp_clear_xmit_timers(struct sock *sk)
 223 {
 224         inet_csk_clear_xmit_timers(sk);
 225 }
 226
 227 extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu);
 228
 229 extern const char *dccp_packet_name(const int type);
 230 extern const char *dccp_state_name(const int state);
 231
 232 extern void dccp_set_state(struct sock *sk, const int state);
 233 extern void dccp_done(struct sock *sk);
 234
 235 extern void dccp_reqsk_init(struct request_sock *req, struct sk_buff *skb);
 236
 237 extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
 238
 239 extern struct sock *dccp_create_openreq_child(struct sock *sk,
 240                                               const struct request_sock *req,
 241                                               const struct sk_buff *skb);
 242
 243 extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb);
 244
 245 extern struct sock *dccp_v4_request_recv_sock(struct sock *sk,
 246                                               struct sk_buff *skb,
 247                                               struct request_sock *req,
 248                                               struct dst_entry *dst);
 249 extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb,
 250                                    struct request_sock *req,
 251                                    struct request_sock **prev);
 252
 253 extern int dccp_child_process(struct sock *parent, struct sock *child,
 254                               struct sk_buff *skb);
 255 extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 256                                   struct dccp_hdr *dh, unsigned len);
 257 extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
 258                                 const struct dccp_hdr *dh, const unsigned len);
 259
 260 extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized);
 261 extern int dccp_destroy_sock(struct sock *sk);
 262
 263 extern void             dccp_close(struct sock *sk, long timeout);
 264 extern struct sk_buff   *dccp_make_response(struct sock *sk,
 265                                             struct dst_entry *dst,
 266                                             struct request_sock *req);
 267
 268 extern int         dccp_connect(struct sock *sk);
 269 extern int         dccp_disconnect(struct sock *sk, int flags);
 270 extern void        dccp_hash(struct sock *sk);
 271 extern void        dccp_unhash(struct sock *sk);
 272 extern int         dccp_getsockopt(struct sock *sk, int level, int optname,
 273                                    char __user *optval, int __user *optlen);
 274 extern int         dccp_setsockopt(struct sock *sk, int level, int optname,
 275                                    char __user *optval, int optlen);
 276 #ifdef CONFIG_COMPAT
 277 extern int         compat_dccp_getsockopt(struct sock *sk,
 278                                 int level, int optname,
 279                                 char __user *optval, int __user *optlen);
 280 extern int         compat_dccp_setsockopt(struct sock *sk,
 281                                 int level, int optname,
 282                                 char __user *optval, int optlen);
 283 #endif
 284 extern int         dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
 285 extern int         dccp_sendmsg(struct kiocb *iocb, struct sock *sk,
 286                                 struct msghdr *msg, size_t size);
 287 extern int         dccp_recvmsg(struct kiocb *iocb, struct sock *sk,
 288                                 struct msghdr *msg, size_t len, int nonblock,
 289                                 int flags, int *addr_len);
 290 extern void        dccp_shutdown(struct sock *sk, int how);
 291 extern int         inet_dccp_listen(struct socket *sock, int backlog);
 292 extern unsigned int dccp_poll(struct file *file, struct socket *sock,
 293                              poll_table *wait);
 294 extern int         dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
 295                                    int addr_len);
 296
 297 extern int         dccp_send_reset(struct sock *sk, enum dccp_reset_codes code);
 298 extern void        dccp_send_close(struct sock *sk, const int active);
 299 extern int         dccp_invalid_packet(struct sk_buff *skb);
 300 extern u32         dccp_sample_rtt(struct sock *sk, ktime_t t_recv,
 301                                    ktime_t *t_history);
 302
 303 static inline int dccp_bad_service_code(const struct sock *sk,
 304                                         const __be32 service)
 305 {
 306         const struct dccp_sock *dp = dccp_sk(sk);
 307
 308         if (dp->dccps_service == service)
 309                 return 0;
 310         return !dccp_list_has_service(dp->dccps_service_list, service);
 311 }
 312
 313 struct dccp_skb_cb {
 314         __u8  dccpd_type:4;
 315         __u8  dccpd_ccval:4;
 316         __u8  dccpd_reset_code;
 317         __u16 dccpd_opt_len;
 318         __u64 dccpd_seq;
 319         __u64 dccpd_ack_seq;
 320 };
 321
 322 #define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
 323
 324 static inline int dccp_non_data_packet(const struct sk_buff *skb)
 325 {
 326         const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
 327
 328         return type == DCCP_PKT_ACK      ||
 329                type == DCCP_PKT_CLOSE    ||
 330                type == DCCP_PKT_CLOSEREQ ||
 331                type == DCCP_PKT_RESET    ||
 332                type == DCCP_PKT_SYNC     ||
 333                type == DCCP_PKT_SYNCACK;
 334 }
 335
 336 static inline int dccp_packet_without_ack(const struct sk_buff *skb)
 337 {
 338         const __u8 type = DCCP_SKB_CB(skb)->dccpd_type;
 339
 340         return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST;
 341 }
 342
 343 #define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2)
 344
 345 static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss)
 346 {
 347         struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh +
 348                                                            sizeof(*dh));
 349         dh->dccph_seq2 = 0;
 350         dh->dccph_seq = htons((gss >> 32) & 0xfffff);
 351         dhx->dccph_seq_low = htonl(gss & 0xffffffff);
 352 }
 353
 354 static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack,
 355                                     const u64 gsr)
 356 {
 357         dhack->dccph_reserved1 = 0;
 358         dhack->dccph_ack_nr_high = htons(gsr >> 32);
 359         dhack->dccph_ack_nr_low  = htonl(gsr & 0xffffffff);
 360 }
 361
 362 static inline void dccp_update_gsr(struct sock *sk, u64 seq)
 363 {
 364         struct dccp_sock *dp = dccp_sk(sk);
 365         const struct dccp_minisock *dmsk = dccp_msk(sk);
 366
 367         dp->dccps_gsr = seq;
 368         dccp_set_seqno(&dp->dccps_swl,
 369                        dp->dccps_gsr + 1 - (dmsk->dccpms_sequence_window / 4));
 370         dccp_set_seqno(&dp->dccps_swh,
 371                        dp->dccps_gsr + (3 * dmsk->dccpms_sequence_window) / 4);
 372 }
 373
 374 static inline void dccp_update_gss(struct sock *sk, u64 seq)
 375 {
 376         struct dccp_sock *dp = dccp_sk(sk);
 377
 378         dp->dccps_awh = dp->dccps_gss = seq;
 379         dccp_set_seqno(&dp->dccps_awl,
 380                        (dp->dccps_gss -
 381                         dccp_msk(sk)->dccpms_sequence_window + 1));
 382 }
 383
 384 static inline int dccp_ack_pending(const struct sock *sk)
 385 {
 386         const struct dccp_sock *dp = dccp_sk(sk);
 387         return dp->dccps_timestamp_echo != 0 ||
 388 #ifdef CONFIG_IP_DCCP_ACKVEC
 389                (dccp_msk(sk)->dccpms_send_ack_vector &&
 390                 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
 391 #endif
 392                inet_csk_ack_scheduled(sk);
 393 }
 394
 395 extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
 396 extern int dccp_insert_option_elapsed_time(struct sock *sk,
 397                                             struct sk_buff *skb,
 398                                             u32 elapsed_time);
 399 extern u32 dccp_timestamp(void);
 400 extern void dccp_timestamping_init(void);
 401 extern int dccp_insert_option_timestamp(struct sock *sk,
 402                                          struct sk_buff *skb);
 403 extern int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
 404                                unsigned char option,
 405                                const void *value, unsigned char len);
 406
 407 #ifdef CONFIG_SYSCTL
 408 extern int dccp_sysctl_init(void);
 409 extern void dccp_sysctl_exit(void);
 410 #else
 411 static inline int dccp_sysctl_init(void)
 412 {
 413         return 0;
 414 }
 415
 416 static inline void dccp_sysctl_exit(void)
 417 {
 418 }
 419 #endif
 420
 421 #endif /* _DCCP_H */