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   1 /*
   2  * NET          Generic infrastructure for INET connection oriented protocols.
   3  *
   4  *              Definitions for inet_connection_sock
   5  *
   6  * Authors:     Many people, see the TCP sources
   7  *
   8  *              From code originally in TCP
   9  *
  10  *              This program is free software; you can redistribute it and/or
  11  *              modify it under the terms of the GNU General Public License
  12  *              as published by the Free Software Foundation; either version
  13  *              2 of the License, or (at your option) any later version.
  14  */
  15 #ifndef _INET_CONNECTION_SOCK_H
  16 #define _INET_CONNECTION_SOCK_H
  17
  18 #include <linux/ip.h>
  19 #include <linux/string.h>
  20 #include <linux/timer.h>
  21 #include <net/request_sock.h>
  22
  23 #define INET_CSK_DEBUG 1
  24
  25 /* Cancel timers, when they are not required. */
  26 #undef INET_CSK_CLEAR_TIMERS
  27
  28 struct inet_bind_bucket;
  29 struct inet_hashinfo;
  30 struct tcp_congestion_ops;
  31
  32 /** inet_connection_sock - INET connection oriented sock
  33  *
  34  * @icsk_accept_queue:     FIFO of established children
  35  * @icsk_bind_hash:        Bind node
  36  * @icsk_timeout:          Timeout
  37  * @icsk_retransmit_timer: Resend (no ack)
  38  * @icsk_rto:              Retransmit timeout
  39  * @icsk_ca_ops            Pluggable congestion control hook
  40  * @icsk_ca_state:         Congestion control state
  41  * @icsk_retransmits:      Number of unrecovered [RTO] timeouts
  42  * @icsk_pending:          Scheduled timer event
  43  * @icsk_backoff:          Backoff
  44  * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
  45  * @icsk_probes_out:       unanswered 0 window probes
  46  * @icsk_ack:              Delayed ACK control data
  47  */
  48 struct inet_connection_sock {
  49         /* inet_sock has to be the first member! */
  50         struct inet_sock          icsk_inet;
  51         struct request_sock_queue icsk_accept_queue;
  52         struct inet_bind_bucket   *icsk_bind_hash;
  53         unsigned long             icsk_timeout;
  54         struct timer_list         icsk_retransmit_timer;
  55         struct timer_list         icsk_delack_timer;
  56         __u32                     icsk_rto;
  57         struct tcp_congestion_ops *icsk_ca_ops;
  58         __u8                      icsk_ca_state;
  59         __u8                      icsk_retransmits;
  60         __u8                      icsk_pending;
  61         __u8                      icsk_backoff;
  62         __u8                      icsk_syn_retries;
  63         __u8                      icsk_probes_out;
  64         /* 2 BYTES HOLE, TRY TO PACK! */
  65         struct {
  66                 __u8              pending;       /* ACK is pending                         */
  67                 __u8              quick;         /* Scheduled number of quick acks         */
  68                 __u8              pingpong;      /* The session is interactive             */
  69                 __u8              blocked;       /* Delayed ACK was blocked by socket lock */
  70                 __u32             ato;           /* Predicted tick of soft clock           */
  71                 unsigned long     timeout;       /* Currently scheduled timeout            */
  72                 __u32             lrcvtime;      /* timestamp of last received data packet */
  73                 __u16             last_seg_size; /* Size of last incoming segment          */
  74                 __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */
  75         } icsk_ack;
  76         u32                       icsk_ca_priv[16];
  77 #define ICSK_CA_PRIV_SIZE       (16 * sizeof(u32))
  78 };
  79
  80 #define ICSK_TIME_RETRANS       1       /* Retransmit timer */
  81 #define ICSK_TIME_DACK          2       /* Delayed ack timer */
  82 #define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
  83 #define ICSK_TIME_KEEPOPEN      4       /* Keepalive timer */
  84
  85 static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
  86 {
  87         return (struct inet_connection_sock *)sk;
  88 }
  89
  90 static inline void *inet_csk_ca(const struct sock *sk)
  91 {
  92         return (void *)inet_csk(sk)->icsk_ca_priv;
  93 }
  94
  95 extern struct sock *inet_csk_clone(struct sock *sk,
  96                                    const struct request_sock *req,
  97                                    const gfp_t priority);
  98
  99 enum inet_csk_ack_state_t {
 100         ICSK_ACK_SCHED  = 1,
 101         ICSK_ACK_TIMER  = 2,
 102         ICSK_ACK_PUSHED = 4
 103 };
 104
 105 extern void inet_csk_init_xmit_timers(struct sock *sk,
 106                                       void (*retransmit_handler)(unsigned long),
 107                                       void (*delack_handler)(unsigned long),
 108                                       void (*keepalive_handler)(unsigned long));
 109 extern void inet_csk_clear_xmit_timers(struct sock *sk);
 110
 111 static inline void inet_csk_schedule_ack(struct sock *sk)
 112 {
 113         inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
 114 }
 115
 116 static inline int inet_csk_ack_scheduled(const struct sock *sk)
 117 {
 118         return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
 119 }
 120
 121 static inline void inet_csk_delack_init(struct sock *sk)
 122 {
 123         memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
 124 }
 125
 126 extern void inet_csk_delete_keepalive_timer(struct sock *sk);
 127 extern void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
 128
 129 #ifdef INET_CSK_DEBUG
 130 extern const char inet_csk_timer_bug_msg[];
 131 #endif
 132
 133 static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
 134 {
 135         struct inet_connection_sock *icsk = inet_csk(sk);
 136
 137         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 138                 icsk->icsk_pending = 0;
 139 #ifdef INET_CSK_CLEAR_TIMERS
 140                 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 141 #endif
 142         } else if (what == ICSK_TIME_DACK) {
 143                 icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
 144 #ifdef INET_CSK_CLEAR_TIMERS
 145                 sk_stop_timer(sk, &icsk->icsk_delack_timer);
 146 #endif
 147         }
 148 #ifdef INET_CSK_DEBUG
 149         else {
 150                 pr_debug("%s", inet_csk_timer_bug_msg);
 151         }
 152 #endif
 153 }
 154
 155 /*
 156  *      Reset the retransmission timer
 157  */
 158 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
 159                                              unsigned long when,
 160                                              const unsigned long max_when)
 161 {
 162         struct inet_connection_sock *icsk = inet_csk(sk);
 163
 164         if (when > max_when) {
 165 #ifdef INET_CSK_DEBUG
 166                 pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
 167                          sk, what, when, current_text_addr());
 168 #endif
 169                 when = max_when;
 170         }
 171
 172         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 173                 icsk->icsk_pending = what;
 174                 icsk->icsk_timeout = jiffies + when;
 175                 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
 176         } else if (what == ICSK_TIME_DACK) {
 177                 icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
 178                 icsk->icsk_ack.timeout = jiffies + when;
 179                 sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
 180         }
 181 #ifdef INET_CSK_DEBUG
 182         else {
 183                 pr_debug("%s", inet_csk_timer_bug_msg);
 184         }
 185 #endif
 186 }
 187
 188 extern struct sock *inet_csk_accept(struct sock *sk, int flags, int *err);
 189
 190 extern struct request_sock *inet_csk_search_req(const struct sock *sk,
 191                                                 struct request_sock ***prevp,
 192                                                 const __u16 rport,
 193                                                 const __u32 raddr,
 194                                                 const __u32 laddr);
 195 extern int inet_csk_get_port(struct inet_hashinfo *hashinfo,
 196                              struct sock *sk, unsigned short snum);
 197
 198 extern struct dst_entry* inet_csk_route_req(struct sock *sk,
 199                                             const struct request_sock *req);
 200
 201 static inline void inet_csk_reqsk_queue_add(struct sock *sk,
 202                                             struct request_sock *req,
 203                                             struct sock *child)
 204 {
 205         reqsk_queue_add(&inet_csk(sk)->icsk_accept_queue, req, sk, child);
 206 }
 207
 208 extern void inet_csk_reqsk_queue_hash_add(struct sock *sk,
 209                                           struct request_sock *req,
 210                                           const unsigned timeout);
 211
 212 static inline void inet_csk_reqsk_queue_removed(struct sock *sk,
 213                                                 struct request_sock *req)
 214 {
 215         if (reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req) == 0)
 216                 inet_csk_delete_keepalive_timer(sk);
 217 }
 218
 219 static inline void inet_csk_reqsk_queue_added(struct sock *sk,
 220                                               const unsigned long timeout)
 221 {
 222         if (reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue) == 0)
 223                 inet_csk_reset_keepalive_timer(sk, timeout);
 224 }
 225
 226 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
 227 {
 228         return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
 229 }
 230
 231 static inline int inet_csk_reqsk_queue_young(const struct sock *sk)
 232 {
 233         return reqsk_queue_len_young(&inet_csk(sk)->icsk_accept_queue);
 234 }
 235
 236 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
 237 {
 238         return reqsk_queue_is_full(&inet_csk(sk)->icsk_accept_queue);
 239 }
 240
 241 static inline void inet_csk_reqsk_queue_unlink(struct sock *sk,
 242                                                struct request_sock *req,
 243                                                struct request_sock **prev)
 244 {
 245         reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req, prev);
 246 }
 247
 248 static inline void inet_csk_reqsk_queue_drop(struct sock *sk,
 249                                              struct request_sock *req,
 250                                              struct request_sock **prev)
 251 {
 252         inet_csk_reqsk_queue_unlink(sk, req, prev);
 253         inet_csk_reqsk_queue_removed(sk, req);
 254         reqsk_free(req);
 255 }
 256
 257 extern void inet_csk_reqsk_queue_prune(struct sock *parent,
 258                                        const unsigned long interval,
 259                                        const unsigned long timeout,
 260                                        const unsigned long max_rto);
 261
 262 extern void inet_csk_destroy_sock(struct sock *sk);
 263
 264 /*
 265  * LISTEN is a special case for poll..
 266  */
 267 static inline unsigned int inet_csk_listen_poll(const struct sock *sk)
 268 {
 269         return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
 270                         (POLLIN | POLLRDNORM) : 0;
 271 }
 272
 273 extern int  inet_csk_listen_start(struct sock *sk, const int nr_table_entries);
 274 extern void inet_csk_listen_stop(struct sock *sk);
 275
 276 #endif /* _INET_CONNECTION_SOCK_H */