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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/compiler.h>
  19 #include <linux/string.h>
  20 #include <linux/timer.h>
  21
  22 #include <net/inet_sock.h>
  23 #include <net/request_sock.h>
  24
  25 #define INET_CSK_DEBUG 1
  26
  27 /* Cancel timers, when they are not required. */
  28 #undef INET_CSK_CLEAR_TIMERS
  29
  30 struct inet_bind_bucket;
  31 struct inet_hashinfo;
  32 struct tcp_congestion_ops;
  33
  34 /*
  35  * Pointers to address related TCP functions
  36  * (i.e. things that depend on the address family)
  37  */
  38 struct inet_connection_sock_af_ops {
  39         int         (*queue_xmit)(struct sk_buff *skb, int ipfragok);
  40         void        (*send_check)(struct sock *sk, int len,
  41                                   struct sk_buff *skb);
  42         int         (*rebuild_header)(struct sock *sk);
  43         int         (*conn_request)(struct sock *sk, struct sk_buff *skb);
  44         struct sock *(*syn_recv_sock)(struct sock *sk, struct sk_buff *skb,
  45                                       struct request_sock *req,
  46                                       struct dst_entry *dst);
  47         int         (*remember_stamp)(struct sock *sk);
  48         __u16       net_header_len;
  49         int         (*setsockopt)(struct sock *sk, int level, int optname,
  50                                   char __user *optval, int optlen);
  51         int         (*getsockopt)(struct sock *sk, int level, int optname,
  52                                   char __user *optval, int __user *optlen);
  53         void        (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
  54         int sockaddr_len;
  55 };
  56
  57 /** inet_connection_sock - INET connection oriented sock
  58  *
  59  * @icsk_accept_queue:     FIFO of established children
  60  * @icsk_bind_hash:        Bind node
  61  * @icsk_timeout:          Timeout
  62  * @icsk_retransmit_timer: Resend (no ack)
  63  * @icsk_rto:              Retransmit timeout
  64  * @icsk_pmtu_cookie       Last pmtu seen by socket
  65  * @icsk_ca_ops            Pluggable congestion control hook
  66  * @icsk_af_ops            Operations which are AF_INET{4,6} specific
  67  * @icsk_ca_state:         Congestion control state
  68  * @icsk_retransmits:      Number of unrecovered [RTO] timeouts
  69  * @icsk_pending:          Scheduled timer event
  70  * @icsk_backoff:          Backoff
  71  * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
  72  * @icsk_probes_out:       unanswered 0 window probes
  73  * @icsk_ext_hdr_len:      Network protocol overhead (IP/IPv6 options)
  74  * @icsk_ack:              Delayed ACK control data
  75  * @icsk_mtup;             MTU probing control data
  76  */
  77 struct inet_connection_sock {
  78         /* inet_sock has to be the first member! */
  79         struct inet_sock          icsk_inet;
  80         struct request_sock_queue icsk_accept_queue;
  81         struct inet_bind_bucket   *icsk_bind_hash;
  82         unsigned long             icsk_timeout;
  83         struct timer_list         icsk_retransmit_timer;
  84         struct timer_list         icsk_delack_timer;
  85         __u32                     icsk_rto;
  86         __u32                     icsk_pmtu_cookie;
  87         const struct tcp_congestion_ops *icsk_ca_ops;
  88         const struct inet_connection_sock_af_ops *icsk_af_ops;
  89         unsigned int              (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
  90         __u8                      icsk_ca_state;
  91         __u8                      icsk_retransmits;
  92         __u8                      icsk_pending;
  93         __u8                      icsk_backoff;
  94         __u8                      icsk_syn_retries;
  95         __u8                      icsk_probes_out;
  96         __u16                     icsk_ext_hdr_len;
  97         struct {
  98                 __u8              pending;       /* ACK is pending                         */
  99                 __u8              quick;         /* Scheduled number of quick acks         */
 100                 __u8              pingpong;      /* The session is interactive             */
 101                 __u8              blocked;       /* Delayed ACK was blocked by socket lock */
 102                 __u32             ato;           /* Predicted tick of soft clock           */
 103                 unsigned long     timeout;       /* Currently scheduled timeout            */
 104                 __u32             lrcvtime;      /* timestamp of last received data packet */
 105                 __u16             last_seg_size; /* Size of last incoming segment          */
 106                 __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */
 107         } icsk_ack;
 108         struct {
 109                 int               enabled;
 110
 111                 /* Range of MTUs to search */
 112                 int               search_high;
 113                 int               search_low;
 114
 115                 /* Information on the current probe. */
 116                 int               probe_size;
 117         } icsk_mtup;
 118         u32                       icsk_ca_priv[16];
 119 #define ICSK_CA_PRIV_SIZE       (16 * sizeof(u32))
 120 };
 121
 122 #define ICSK_TIME_RETRANS       1       /* Retransmit timer */
 123 #define ICSK_TIME_DACK          2       /* Delayed ack timer */
 124 #define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
 125 #define ICSK_TIME_KEEPOPEN      4       /* Keepalive timer */
 126
 127 static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
 128 {
 129         return (struct inet_connection_sock *)sk;
 130 }
 131
 132 static inline void *inet_csk_ca(const struct sock *sk)
 133 {
 134         return (void *)inet_csk(sk)->icsk_ca_priv;
 135 }
 136
 137 extern struct sock *inet_csk_clone(struct sock *sk,
 138                                    const struct request_sock *req,
 139                                    const gfp_t priority);
 140
 141 enum inet_csk_ack_state_t {
 142         ICSK_ACK_SCHED  = 1,
 143         ICSK_ACK_TIMER  = 2,
 144         ICSK_ACK_PUSHED = 4
 145 };
 146
 147 extern void inet_csk_init_xmit_timers(struct sock *sk,
 148                                       void (*retransmit_handler)(unsigned long),
 149                                       void (*delack_handler)(unsigned long),
 150                                       void (*keepalive_handler)(unsigned long));
 151 extern void inet_csk_clear_xmit_timers(struct sock *sk);
 152
 153 static inline void inet_csk_schedule_ack(struct sock *sk)
 154 {
 155         inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
 156 }
 157
 158 static inline int inet_csk_ack_scheduled(const struct sock *sk)
 159 {
 160         return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
 161 }
 162
 163 static inline void inet_csk_delack_init(struct sock *sk)
 164 {
 165         memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
 166 }
 167
 168 extern void inet_csk_delete_keepalive_timer(struct sock *sk);
 169 extern void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
 170
 171 #ifdef INET_CSK_DEBUG
 172 extern const char inet_csk_timer_bug_msg[];
 173 #endif
 174
 175 static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
 176 {
 177         struct inet_connection_sock *icsk = inet_csk(sk);
 178
 179         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 180                 icsk->icsk_pending = 0;
 181 #ifdef INET_CSK_CLEAR_TIMERS
 182                 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 183 #endif
 184         } else if (what == ICSK_TIME_DACK) {
 185                 icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
 186 #ifdef INET_CSK_CLEAR_TIMERS
 187                 sk_stop_timer(sk, &icsk->icsk_delack_timer);
 188 #endif
 189         }
 190 #ifdef INET_CSK_DEBUG
 191         else {
 192                 pr_debug("%s", inet_csk_timer_bug_msg);
 193         }
 194 #endif
 195 }
 196
 197 /*
 198  *      Reset the retransmission timer
 199  */
 200 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
 201                                              unsigned long when,
 202                                              const unsigned long max_when)
 203 {
 204         struct inet_connection_sock *icsk = inet_csk(sk);
 205
 206         if (when > max_when) {
 207 #ifdef INET_CSK_DEBUG
 208                 pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
 209                          sk, what, when, current_text_addr());
 210 #endif
 211                 when = max_when;
 212         }
 213
 214         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 215                 icsk->icsk_pending = what;
 216                 icsk->icsk_timeout = jiffies + when;
 217                 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
 218         } else if (what == ICSK_TIME_DACK) {
 219                 icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
 220                 icsk->icsk_ack.timeout = jiffies + when;
 221                 sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
 222         }
 223 #ifdef INET_CSK_DEBUG
 224         else {
 225                 pr_debug("%s", inet_csk_timer_bug_msg);
 226         }
 227 #endif
 228 }
 229
 230 extern struct sock *inet_csk_accept(struct sock *sk, int flags, int *err);
 231
 232 extern struct request_sock *inet_csk_search_req(const struct sock *sk,
 233                                                 struct request_sock ***prevp,
 234                                                 const __u16 rport,
 235                                                 const __u32 raddr,
 236                                                 const __u32 laddr);
 237 extern int inet_csk_bind_conflict(const struct sock *sk,
 238                                   const struct inet_bind_bucket *tb);
 239 extern int inet_csk_get_port(struct inet_hashinfo *hashinfo,
 240                              struct sock *sk, unsigned short snum,
 241                              int (*bind_conflict)(const struct sock *sk,
 242                                                   const struct inet_bind_bucket *tb));
 243
 244 extern struct dst_entry* inet_csk_route_req(struct sock *sk,
 245                                             const struct request_sock *req);
 246
 247 static inline void inet_csk_reqsk_queue_add(struct sock *sk,
 248                                             struct request_sock *req,
 249                                             struct sock *child)
 250 {
 251         reqsk_queue_add(&inet_csk(sk)->icsk_accept_queue, req, sk, child);
 252 }
 253
 254 extern void inet_csk_reqsk_queue_hash_add(struct sock *sk,
 255                                           struct request_sock *req,
 256                                           unsigned long timeout);
 257
 258 static inline void inet_csk_reqsk_queue_removed(struct sock *sk,
 259                                                 struct request_sock *req)
 260 {
 261         if (reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req) == 0)
 262                 inet_csk_delete_keepalive_timer(sk);
 263 }
 264
 265 static inline void inet_csk_reqsk_queue_added(struct sock *sk,
 266                                               const unsigned long timeout)
 267 {
 268         if (reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue) == 0)
 269                 inet_csk_reset_keepalive_timer(sk, timeout);
 270 }
 271
 272 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
 273 {
 274         return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
 275 }
 276
 277 static inline int inet_csk_reqsk_queue_young(const struct sock *sk)
 278 {
 279         return reqsk_queue_len_young(&inet_csk(sk)->icsk_accept_queue);
 280 }
 281
 282 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
 283 {
 284         return reqsk_queue_is_full(&inet_csk(sk)->icsk_accept_queue);
 285 }
 286
 287 static inline void inet_csk_reqsk_queue_unlink(struct sock *sk,
 288                                                struct request_sock *req,
 289                                                struct request_sock **prev)
 290 {
 291         reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req, prev);
 292 }
 293
 294 static inline void inet_csk_reqsk_queue_drop(struct sock *sk,
 295                                              struct request_sock *req,
 296                                              struct request_sock **prev)
 297 {
 298         inet_csk_reqsk_queue_unlink(sk, req, prev);
 299         inet_csk_reqsk_queue_removed(sk, req);
 300         reqsk_free(req);
 301 }
 302
 303 extern void inet_csk_reqsk_queue_prune(struct sock *parent,
 304                                        const unsigned long interval,
 305                                        const unsigned long timeout,
 306                                        const unsigned long max_rto);
 307
 308 extern void inet_csk_destroy_sock(struct sock *sk);
 309
 310 /*
 311  * LISTEN is a special case for poll..
 312  */
 313 static inline unsigned int inet_csk_listen_poll(const struct sock *sk)
 314 {
 315         return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
 316                         (POLLIN | POLLRDNORM) : 0;
 317 }
 318
 319 extern int  inet_csk_listen_start(struct sock *sk, const int nr_table_entries);
 320 extern void inet_csk_listen_stop(struct sock *sk);
 321
 322 extern void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
 323
 324 #endif /* _INET_CONNECTION_SOCK_H */