include/net/inet_connection_sock.h

   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
  31 /** inet_connection_sock - INET connection oriented sock
  32  *
  33  * @icsk_accept_queue:     FIFO of established children
  34  * @icsk_bind_hash:        Bind node
  35  * @icsk_timeout:          Timeout
  36  * @icsk_retransmit_timer: Resend (no ack)
  37  * @icsk_rto:              Retransmit timeout
  38  * @icsk_retransmits:      Number of unrecovered [RTO] timeouts
  39  * @icsk_pending:          Scheduled timer event
  40  * @icsk_backoff:          Backoff
  41  * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
  42  * @icsk_ack:              Delayed ACK control data
  43  */
  44 struct inet_connection_sock {
  45         /* inet_sock has to be the first member! */
  46         struct inet_sock          icsk_inet;
  47         struct request_sock_queue icsk_accept_queue;
  48         struct inet_bind_bucket   *icsk_bind_hash;
  49         unsigned long             icsk_timeout;
  50         struct timer_list         icsk_retransmit_timer;
  51         struct timer_list         icsk_delack_timer;
  52         __u32                     icsk_rto;
  53         __u8                      icsk_retransmits;
  54         __u8                      icsk_pending;
  55         __u8                      icsk_backoff;
  56         __u8                      icsk_syn_retries;
  57         struct {
  58                 __u8              pending;       /* ACK is pending                         */
  59                 __u8              quick;         /* Scheduled number of quick acks         */
  60                 __u8              pingpong;      /* The session is interactive             */
  61                 __u8              blocked;       /* Delayed ACK was blocked by socket lock */
  62                 __u32             ato;           /* Predicted tick of soft clock           */
  63                 unsigned long     timeout;       /* Currently scheduled timeout            */
  64                 __u32             lrcvtime;      /* timestamp of last received data packet */
  65                 __u16             last_seg_size; /* Size of last incoming segment          */
  66                 __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */
  67         } icsk_ack;
  68 };
  69
  70 #define ICSK_TIME_RETRANS       1       /* Retransmit timer */
  71 #define ICSK_TIME_DACK          2       /* Delayed ack timer */
  72 #define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
  73 #define ICSK_TIME_KEEPOPEN      4       /* Keepalive timer */
  74
  75 static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
  76 {
  77         return (struct inet_connection_sock *)sk;
  78 }
  79
  80 enum inet_csk_ack_state_t {
  81         ICSK_ACK_SCHED  = 1,
  82         ICSK_ACK_TIMER  = 2,
  83         ICSK_ACK_PUSHED = 4
  84 };
  85
  86 extern void inet_csk_init_xmit_timers(struct sock *sk,
  87                                       void (*retransmit_handler)(unsigned long),
  88                                       void (*delack_handler)(unsigned long),
  89                                       void (*keepalive_handler)(unsigned long));
  90 extern void inet_csk_clear_xmit_timers(struct sock *sk);
  91
  92 static inline void inet_csk_schedule_ack(struct sock *sk)
  93 {
  94         inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
  95 }
  96
  97 static inline int inet_csk_ack_scheduled(const struct sock *sk)
  98 {
  99         return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
 100 }
 101
 102 static inline void inet_csk_delack_init(struct sock *sk)
 103 {
 104         memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
 105 }
 106
 107 extern void inet_csk_delete_keepalive_timer(struct sock *sk);
 108 extern void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
 109
 110 #ifdef INET_CSK_DEBUG
 111 extern const char inet_csk_timer_bug_msg[];
 112 #endif
 113
 114 static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
 115 {
 116         struct inet_connection_sock *icsk = inet_csk(sk);
 117
 118         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 119                 icsk->icsk_pending = 0;
 120 #ifdef INET_CSK_CLEAR_TIMERS
 121                 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 122 #endif
 123         } else if (what == ICSK_TIME_DACK) {
 124                 icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
 125 #ifdef INET_CSK_CLEAR_TIMERS
 126                 sk_stop_timer(sk, &icsk->icsk_delack_timer);
 127 #endif
 128         }
 129 #ifdef INET_CSK_DEBUG
 130         else {
 131                 pr_debug(inet_csk_timer_bug_msg);
 132         }
 133 #endif
 134 }
 135
 136 /*
 137  *      Reset the retransmission timer
 138  */
 139 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
 140                                              unsigned long when,
 141                                              const unsigned long max_when)
 142 {
 143         struct inet_connection_sock *icsk = inet_csk(sk);
 144
 145         if (when > max_when) {
 146 #ifdef INET_CSK_DEBUG
 147                 pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
 148                          sk, what, when, current_text_addr());
 149 #endif
 150                 when = max_when;
 151         }
 152
 153         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 154                 icsk->icsk_pending = what;
 155                 icsk->icsk_timeout = jiffies + when;
 156                 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
 157         } else if (what == ICSK_TIME_DACK) {
 158                 icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
 159                 icsk->icsk_ack.timeout = jiffies + when;
 160                 sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
 161         }
 162 #ifdef INET_CSK_DEBUG
 163         else {
 164                 pr_debug(inet_csk_timer_bug_msg);
 165         }
 166 #endif
 167 }
 168
 169 extern struct sock *inet_csk_accept(struct sock *sk, int flags, int *err);
 170
 171 extern struct request_sock *inet_csk_search_req(const struct sock *sk,
 172                                                 struct request_sock ***prevp,
 173                                                 const __u16 rport,
 174                                                 const __u32 raddr,
 175                                                 const __u32 laddr);
 176 extern int inet_csk_get_port(struct inet_hashinfo *hashinfo,
 177                              struct sock *sk, unsigned short snum);
 178
 179 extern struct dst_entry* inet_csk_route_req(struct sock *sk,
 180                                             const struct request_sock *req);
 181
 182 static inline void inet_csk_reqsk_queue_add(struct sock *sk,
 183                                             struct request_sock *req,
 184                                             struct sock *child)
 185 {
 186         reqsk_queue_add(&inet_csk(sk)->icsk_accept_queue, req, sk, child);
 187 }
 188
 189 extern void inet_csk_reqsk_queue_hash_add(struct sock *sk,
 190                                           struct request_sock *req,
 191                                           const unsigned timeout);
 192
 193 static inline void inet_csk_reqsk_queue_removed(struct sock *sk,
 194                                                 struct request_sock *req)
 195 {
 196         if (reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req) == 0)
 197                 inet_csk_delete_keepalive_timer(sk);
 198 }
 199
 200 static inline void inet_csk_reqsk_queue_added(struct sock *sk,
 201                                               const unsigned long timeout)
 202 {
 203         if (reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue) == 0)
 204                 inet_csk_reset_keepalive_timer(sk, timeout);
 205 }
 206
 207 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
 208 {
 209         return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
 210 }
 211
 212 static inline int inet_csk_reqsk_queue_young(const struct sock *sk)
 213 {
 214         return reqsk_queue_len_young(&inet_csk(sk)->icsk_accept_queue);
 215 }
 216
 217 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
 218 {
 219         return reqsk_queue_is_full(&inet_csk(sk)->icsk_accept_queue);
 220 }
 221
 222 static inline void inet_csk_reqsk_queue_unlink(struct sock *sk,
 223                                                struct request_sock *req,
 224                                                struct request_sock **prev)
 225 {
 226         reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req, prev);
 227 }
 228
 229 static inline void inet_csk_reqsk_queue_drop(struct sock *sk,
 230                                              struct request_sock *req,
 231                                              struct request_sock **prev)
 232 {
 233         inet_csk_reqsk_queue_unlink(sk, req, prev);
 234         inet_csk_reqsk_queue_removed(sk, req);
 235         reqsk_free(req);
 236 }
 237
 238 #endif /* _INET_CONNECTION_SOCK_H */