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/compiler.h>
  19 #include <linux/string.h>
  20 #include <linux/timer.h>
  21 #include <linux/poll.h>
  22
  23 #include <net/inet_sock.h>
  24 #include <net/request_sock.h>
  25
  26 #define INET_CSK_DEBUG 1
  27
  28 /* Cancel timers, when they are not required. */
  29 #undef INET_CSK_CLEAR_TIMERS
  30
  31 struct inet_bind_bucket;
  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 sock *sk, struct sk_buff *skb, struct flowi *fl);
  40         void        (*send_check)(struct sock *sk, struct sk_buff *skb);
  41         int         (*rebuild_header)(struct sock *sk);
  42         void        (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
  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         u16         net_header_len;
  48         u16         net_frag_header_len;
  49         u16         sockaddr_len;
  50         int         (*setsockopt)(struct sock *sk, int level, int optname,
  51                                   char __user *optval, unsigned int optlen);
  52         int         (*getsockopt)(struct sock *sk, int level, int optname,
  53                                   char __user *optval, int __user *optlen);
  54 #ifdef CONFIG_COMPAT
  55         int         (*compat_setsockopt)(struct sock *sk,
  56                                 int level, int optname,
  57                                 char __user *optval, unsigned int optlen);
  58         int         (*compat_getsockopt)(struct sock *sk,
  59                                 int level, int optname,
  60                                 char __user *optval, int __user *optlen);
  61 #endif
  62         void        (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
  63         int         (*bind_conflict)(const struct sock *sk,
  64                                      const struct inet_bind_bucket *tb, bool relax);
  65         void        (*mtu_reduced)(struct sock *sk);
  66 };
  67
  68 /** inet_connection_sock - INET connection oriented sock
  69  *
  70  * @icsk_accept_queue:     FIFO of established children
  71  * @icsk_bind_hash:        Bind node
  72  * @icsk_timeout:          Timeout
  73  * @icsk_retransmit_timer: Resend (no ack)
  74  * @icsk_rto:              Retransmit timeout
  75  * @icsk_pmtu_cookie       Last pmtu seen by socket
  76  * @icsk_ca_ops            Pluggable congestion control hook
  77  * @icsk_af_ops            Operations which are AF_INET{4,6} specific
  78  * @icsk_ca_state:         Congestion control state
  79  * @icsk_retransmits:      Number of unrecovered [RTO] timeouts
  80  * @icsk_pending:          Scheduled timer event
  81  * @icsk_backoff:          Backoff
  82  * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
  83  * @icsk_probes_out:       unanswered 0 window probes
  84  * @icsk_ext_hdr_len:      Network protocol overhead (IP/IPv6 options)
  85  * @icsk_ack:              Delayed ACK control data
  86  * @icsk_mtup;             MTU probing control data
  87  */
  88 struct inet_connection_sock {
  89         /* inet_sock has to be the first member! */
  90         struct inet_sock          icsk_inet;
  91         struct request_sock_queue icsk_accept_queue;
  92         struct inet_bind_bucket   *icsk_bind_hash;
  93         unsigned long             icsk_timeout;
  94         struct timer_list         icsk_retransmit_timer;
  95         struct timer_list         icsk_delack_timer;
  96         __u32                     icsk_rto;
  97         __u32                     icsk_pmtu_cookie;
  98         const struct tcp_congestion_ops *icsk_ca_ops;
  99         const struct inet_connection_sock_af_ops *icsk_af_ops;
 100         unsigned int              (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
 101         __u8                      icsk_ca_state:7,
 102                                   icsk_ca_dst_locked:1;
 103         __u8                      icsk_retransmits;
 104         __u8                      icsk_pending;
 105         __u8                      icsk_backoff;
 106         __u8                      icsk_syn_retries;
 107         __u8                      icsk_probes_out;
 108         __u16                     icsk_ext_hdr_len;
 109         struct {
 110                 __u8              pending;       /* ACK is pending                         */
 111                 __u8              quick;         /* Scheduled number of quick acks         */
 112                 __u8              pingpong;      /* The session is interactive             */
 113                 __u8              blocked;       /* Delayed ACK was blocked by socket lock */
 114                 __u32             ato;           /* Predicted tick of soft clock           */
 115                 unsigned long     timeout;       /* Currently scheduled timeout            */
 116                 __u32             lrcvtime;      /* timestamp of last received data packet */
 117                 __u16             last_seg_size; /* Size of last incoming segment          */
 118                 __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */
 119         } icsk_ack;
 120         struct {
 121                 int               enabled;
 122
 123                 /* Range of MTUs to search */
 124                 int               search_high;
 125                 int               search_low;
 126
 127                 /* Information on the current probe. */
 128                 int               probe_size;
 129
 130                 u32               probe_timestamp;
 131         } icsk_mtup;
 132         u32                       icsk_ca_priv[16];
 133         u32                       icsk_user_timeout;
 134 #define ICSK_CA_PRIV_SIZE       (16 * sizeof(u32))
 135 };
 136
 137 #define ICSK_TIME_RETRANS       1       /* Retransmit timer */
 138 #define ICSK_TIME_DACK          2       /* Delayed ack timer */
 139 #define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
 140 #define ICSK_TIME_EARLY_RETRANS 4       /* Early retransmit timer */
 141 #define ICSK_TIME_LOSS_PROBE    5       /* Tail loss probe timer */
 142
 143 static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
 144 {
 145         return (struct inet_connection_sock *)sk;
 146 }
 147
 148 static inline void *inet_csk_ca(const struct sock *sk)
 149 {
 150         return (void *)inet_csk(sk)->icsk_ca_priv;
 151 }
 152
 153 struct sock *inet_csk_clone_lock(const struct sock *sk,
 154                                  const struct request_sock *req,
 155                                  const gfp_t priority);
 156
 157 enum inet_csk_ack_state_t {
 158         ICSK_ACK_SCHED  = 1,
 159         ICSK_ACK_TIMER  = 2,
 160         ICSK_ACK_PUSHED = 4,
 161         ICSK_ACK_PUSHED2 = 8
 162 };
 163
 164 void inet_csk_init_xmit_timers(struct sock *sk,
 165                                void (*retransmit_handler)(unsigned long),
 166                                void (*delack_handler)(unsigned long),
 167                                void (*keepalive_handler)(unsigned long));
 168 void inet_csk_clear_xmit_timers(struct sock *sk);
 169
 170 static inline void inet_csk_schedule_ack(struct sock *sk)
 171 {
 172         inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
 173 }
 174
 175 static inline int inet_csk_ack_scheduled(const struct sock *sk)
 176 {
 177         return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
 178 }
 179
 180 static inline void inet_csk_delack_init(struct sock *sk)
 181 {
 182         memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
 183 }
 184
 185 void inet_csk_delete_keepalive_timer(struct sock *sk);
 186 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
 187
 188 #ifdef INET_CSK_DEBUG
 189 extern const char inet_csk_timer_bug_msg[];
 190 #endif
 191
 192 static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
 193 {
 194         struct inet_connection_sock *icsk = inet_csk(sk);
 195
 196         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 197                 icsk->icsk_pending = 0;
 198 #ifdef INET_CSK_CLEAR_TIMERS
 199                 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 200 #endif
 201         } else if (what == ICSK_TIME_DACK) {
 202                 icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
 203 #ifdef INET_CSK_CLEAR_TIMERS
 204                 sk_stop_timer(sk, &icsk->icsk_delack_timer);
 205 #endif
 206         }
 207 #ifdef INET_CSK_DEBUG
 208         else {
 209                 pr_debug("%s", inet_csk_timer_bug_msg);
 210         }
 211 #endif
 212 }
 213
 214 /*
 215  *      Reset the retransmission timer
 216  */
 217 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
 218                                              unsigned long when,
 219                                              const unsigned long max_when)
 220 {
 221         struct inet_connection_sock *icsk = inet_csk(sk);
 222
 223         if (when > max_when) {
 224 #ifdef INET_CSK_DEBUG
 225                 pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
 226                          sk, what, when, current_text_addr());
 227 #endif
 228                 when = max_when;
 229         }
 230
 231         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
 232             what == ICSK_TIME_EARLY_RETRANS || what ==  ICSK_TIME_LOSS_PROBE) {
 233                 icsk->icsk_pending = what;
 234                 icsk->icsk_timeout = jiffies + when;
 235                 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
 236         } else if (what == ICSK_TIME_DACK) {
 237                 icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
 238                 icsk->icsk_ack.timeout = jiffies + when;
 239                 sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
 240         }
 241 #ifdef INET_CSK_DEBUG
 242         else {
 243                 pr_debug("%s", inet_csk_timer_bug_msg);
 244         }
 245 #endif
 246 }
 247
 248 static inline unsigned long
 249 inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
 250                      unsigned long max_when)
 251 {
 252         u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
 253
 254         return (unsigned long)min_t(u64, when, max_when);
 255 }
 256
 257 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err);
 258
 259 struct request_sock *inet_csk_search_req(const struct sock *sk,
 260                                          struct request_sock ***prevp,
 261                                          const __be16 rport,
 262                                          const __be32 raddr,
 263                                          const __be32 laddr);
 264 int inet_csk_bind_conflict(const struct sock *sk,
 265                            const struct inet_bind_bucket *tb, bool relax);
 266 int inet_csk_get_port(struct sock *sk, unsigned short snum);
 267
 268 struct dst_entry *inet_csk_route_req(struct sock *sk, struct flowi4 *fl4,
 269                                      const struct request_sock *req);
 270 struct dst_entry *inet_csk_route_child_sock(struct sock *sk, struct sock *newsk,
 271                                             const struct request_sock *req);
 272
 273 static inline void inet_csk_reqsk_queue_add(struct sock *sk,
 274                                             struct request_sock *req,
 275                                             struct sock *child)
 276 {
 277         reqsk_queue_add(&inet_csk(sk)->icsk_accept_queue, req, sk, child);
 278         /* before letting lookups find us, make sure all req fields
 279          * are committed to memory.
 280          */
 281         smp_wmb();
 282         atomic_set(&req->rsk_refcnt, 1);
 283 }
 284
 285 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 286                                    unsigned long timeout);
 287
 288 static inline void inet_csk_reqsk_queue_removed(struct sock *sk,
 289                                                 struct request_sock *req)
 290 {
 291         if (reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req) == 0)
 292                 inet_csk_delete_keepalive_timer(sk);
 293 }
 294
 295 static inline void inet_csk_reqsk_queue_added(struct sock *sk,
 296                                               const unsigned long timeout)
 297 {
 298         if (reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue) == 0)
 299                 inet_csk_reset_keepalive_timer(sk, timeout);
 300 }
 301
 302 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
 303 {
 304         return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
 305 }
 306
 307 static inline int inet_csk_reqsk_queue_young(const struct sock *sk)
 308 {
 309         return reqsk_queue_len_young(&inet_csk(sk)->icsk_accept_queue);
 310 }
 311
 312 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
 313 {
 314         return reqsk_queue_is_full(&inet_csk(sk)->icsk_accept_queue);
 315 }
 316
 317 static inline void inet_csk_reqsk_queue_unlink(struct sock *sk,
 318                                                struct request_sock *req,
 319                                                struct request_sock **prev)
 320 {
 321         reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req, prev);
 322 }
 323
 324 static inline void inet_csk_reqsk_queue_drop(struct sock *sk,
 325                                              struct request_sock *req,
 326                                              struct request_sock **prev)
 327 {
 328         inet_csk_reqsk_queue_unlink(sk, req, prev);
 329         inet_csk_reqsk_queue_removed(sk, req);
 330         reqsk_free(req);
 331 }
 332
 333 void inet_csk_reqsk_queue_prune(struct sock *parent,
 334                                 const unsigned long interval,
 335                                 const unsigned long timeout,
 336                                 const unsigned long max_rto);
 337
 338 void inet_csk_destroy_sock(struct sock *sk);
 339 void inet_csk_prepare_forced_close(struct sock *sk);
 340
 341 /*
 342  * LISTEN is a special case for poll..
 343  */
 344 static inline unsigned int inet_csk_listen_poll(const struct sock *sk)
 345 {
 346         return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
 347                         (POLLIN | POLLRDNORM) : 0;
 348 }
 349
 350 int inet_csk_listen_start(struct sock *sk, const int nr_table_entries);
 351 void inet_csk_listen_stop(struct sock *sk);
 352
 353 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
 354
 355 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
 356                                char __user *optval, int __user *optlen);
 357 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
 358                                char __user *optval, unsigned int optlen);
 359
 360 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
 361 #endif /* _INET_CONNECTION_SOCK_H */