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