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 #include <linux/kernel.h>
  23
  24 #include <net/inet_sock.h>
  25 #include <net/request_sock.h>
  26
  27 /* Cancel timers, when they are not required. */
  28 #undef INET_CSK_CLEAR_TIMERS
  29
  30 struct inet_bind_bucket;
  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 sock *sk, struct sk_buff *skb, struct flowi *fl);
  39         void        (*send_check)(struct sock *sk, struct sk_buff *skb);
  40         int         (*rebuild_header)(struct sock *sk);
  41         void        (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
  42         int         (*conn_request)(struct sock *sk, struct sk_buff *skb);
  43         struct sock *(*syn_recv_sock)(const struct sock *sk, struct sk_buff *skb,
  44                                       struct request_sock *req,
  45                                       struct dst_entry *dst,
  46                                       struct request_sock *req_unhash,
  47                                       bool *own_req);
  48         u16         net_header_len;
  49         u16         net_frag_header_len;
  50         u16         sockaddr_len;
  51         int         (*setsockopt)(struct sock *sk, int level, int optname,
  52                                   char __user *optval, unsigned int optlen);
  53         int         (*getsockopt)(struct sock *sk, int level, int optname,
  54                                   char __user *optval, int __user *optlen);
  55 #ifdef CONFIG_COMPAT
  56         int         (*compat_setsockopt)(struct sock *sk,
  57                                 int level, int optname,
  58                                 char __user *optval, unsigned int optlen);
  59         int         (*compat_getsockopt)(struct sock *sk,
  60                                 int level, int optname,
  61                                 char __user *optval, int __user *optlen);
  62 #endif
  63         void        (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
  64         void        (*mtu_reduced)(struct sock *sk);
  65 };
  66
  67 /** inet_connection_sock - INET connection oriented sock
  68  *
  69  * @icsk_accept_queue:     FIFO of established children
  70  * @icsk_bind_hash:        Bind node
  71  * @icsk_timeout:          Timeout
  72  * @icsk_retransmit_timer: Resend (no ack)
  73  * @icsk_rto:              Retransmit timeout
  74  * @icsk_pmtu_cookie       Last pmtu seen by socket
  75  * @icsk_ca_ops            Pluggable congestion control hook
  76  * @icsk_af_ops            Operations which are AF_INET{4,6} specific
  77  * @icsk_ulp_ops           Pluggable ULP control hook
  78  * @icsk_ulp_data          ULP private data
  79  * @icsk_clean_acked       Clean acked data hook
  80  * @icsk_listen_portaddr_node   hash to the portaddr listener hashtable
  81  * @icsk_ca_state:         Congestion control state
  82  * @icsk_retransmits:      Number of unrecovered [RTO] timeouts
  83  * @icsk_pending:          Scheduled timer event
  84  * @icsk_backoff:          Backoff
  85  * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
  86  * @icsk_probes_out:       unanswered 0 window probes
  87  * @icsk_ext_hdr_len:      Network protocol overhead (IP/IPv6 options)
  88  * @icsk_ack:              Delayed ACK control data
  89  * @icsk_mtup;             MTU probing control data
  90  */
  91 struct inet_connection_sock {
  92         /* inet_sock has to be the first member! */
  93         struct inet_sock          icsk_inet;
  94         struct request_sock_queue icsk_accept_queue;
  95         struct inet_bind_bucket   *icsk_bind_hash;
  96         unsigned long             icsk_timeout;
  97         struct timer_list         icsk_retransmit_timer;
  98         struct timer_list         icsk_delack_timer;
  99         __u32                     icsk_rto;
 100         __u32                     icsk_pmtu_cookie;
 101         const struct tcp_congestion_ops *icsk_ca_ops;
 102         const struct inet_connection_sock_af_ops *icsk_af_ops;
 103         const struct tcp_ulp_ops  *icsk_ulp_ops;
 104         void                      *icsk_ulp_data;
 105         void (*icsk_clean_acked)(struct sock *sk, u32 acked_seq);
 106         struct hlist_node         icsk_listen_portaddr_node;
 107         unsigned int              (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
 108         __u8                      icsk_ca_state:6,
 109                                   icsk_ca_setsockopt:1,
 110                                   icsk_ca_dst_locked:1;
 111         __u8                      icsk_retransmits;
 112         __u8                      icsk_pending;
 113         __u8                      icsk_backoff;
 114         __u8                      icsk_syn_retries;
 115         __u8                      icsk_probes_out;
 116         __u16                     icsk_ext_hdr_len;
 117         struct {
 118                 __u8              pending;       /* ACK is pending                         */
 119                 __u8              quick;         /* Scheduled number of quick acks         */
 120                 __u8              pingpong;      /* The session is interactive             */
 121                 __u8              blocked;       /* Delayed ACK was blocked by socket lock */
 122                 __u32             ato;           /* Predicted tick of soft clock           */
 123                 unsigned long     timeout;       /* Currently scheduled timeout            */
 124                 __u32             lrcvtime;      /* timestamp of last received data packet */
 125                 __u16             last_seg_size; /* Size of last incoming segment          */
 126                 __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */
 127         } icsk_ack;
 128         struct {
 129                 int               enabled;
 130
 131                 /* Range of MTUs to search */
 132                 int               search_high;
 133                 int               search_low;
 134
 135                 /* Information on the current probe. */
 136                 int               probe_size;
 137
 138                 u32               probe_timestamp;
 139         } icsk_mtup;
 140         u32                       icsk_user_timeout;
 141
 142         u64                       icsk_ca_priv[104 / sizeof(u64)];
 143 #define ICSK_CA_PRIV_SIZE      (13 * sizeof(u64))
 144 };
 145
 146 #define ICSK_TIME_RETRANS       1       /* Retransmit timer */
 147 #define ICSK_TIME_DACK          2       /* Delayed ack timer */
 148 #define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
 149 #define ICSK_TIME_EARLY_RETRANS 4       /* Early retransmit timer */
 150 #define ICSK_TIME_LOSS_PROBE    5       /* Tail loss probe timer */
 151 #define ICSK_TIME_REO_TIMEOUT   6       /* Reordering timer */
 152
 153 static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
 154 {
 155         return (struct inet_connection_sock *)sk;
 156 }
 157
 158 static inline void *inet_csk_ca(const struct sock *sk)
 159 {
 160         return (void *)inet_csk(sk)->icsk_ca_priv;
 161 }
 162
 163 struct sock *inet_csk_clone_lock(const struct sock *sk,
 164                                  const struct request_sock *req,
 165                                  const gfp_t priority);
 166
 167 enum inet_csk_ack_state_t {
 168         ICSK_ACK_SCHED  = 1,
 169         ICSK_ACK_TIMER  = 2,
 170         ICSK_ACK_PUSHED = 4,
 171         ICSK_ACK_PUSHED2 = 8,
 172         ICSK_ACK_NOW = 16       /* Send the next ACK immediately (once) */
 173 };
 174
 175 void inet_csk_init_xmit_timers(struct sock *sk,
 176                                void (*retransmit_handler)(struct timer_list *),
 177                                void (*delack_handler)(struct timer_list *),
 178                                void (*keepalive_handler)(struct timer_list *));
 179 void inet_csk_clear_xmit_timers(struct sock *sk);
 180
 181 static inline void inet_csk_schedule_ack(struct sock *sk)
 182 {
 183         inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
 184 }
 185
 186 static inline int inet_csk_ack_scheduled(const struct sock *sk)
 187 {
 188         return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
 189 }
 190
 191 static inline void inet_csk_delack_init(struct sock *sk)
 192 {
 193         memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
 194 }
 195
 196 void inet_csk_delete_keepalive_timer(struct sock *sk);
 197 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
 198
 199 static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
 200 {
 201         struct inet_connection_sock *icsk = inet_csk(sk);
 202
 203         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 204                 icsk->icsk_pending = 0;
 205 #ifdef INET_CSK_CLEAR_TIMERS
 206                 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 207 #endif
 208         } else if (what == ICSK_TIME_DACK) {
 209                 icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
 210 #ifdef INET_CSK_CLEAR_TIMERS
 211                 sk_stop_timer(sk, &icsk->icsk_delack_timer);
 212 #endif
 213         } else {
 214                 pr_debug("inet_csk BUG: unknown timer value\n");
 215         }
 216 }
 217
 218 /*
 219  *      Reset the retransmission timer
 220  */
 221 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
 222                                              unsigned long when,
 223                                              const unsigned long max_when)
 224 {
 225         struct inet_connection_sock *icsk = inet_csk(sk);
 226
 227         if (when > max_when) {
 228                 pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
 229                          sk, what, when, (void *)_THIS_IP_);
 230                 when = max_when;
 231         }
 232
 233         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
 234             what == ICSK_TIME_EARLY_RETRANS || what == ICSK_TIME_LOSS_PROBE ||
 235             what == ICSK_TIME_REO_TIMEOUT) {
 236                 icsk->icsk_pending = what;
 237                 icsk->icsk_timeout = jiffies + when;
 238                 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
 239         } else if (what == ICSK_TIME_DACK) {
 240                 icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
 241                 icsk->icsk_ack.timeout = jiffies + when;
 242                 sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
 243         } else {
 244                 pr_debug("inet_csk BUG: unknown timer value\n");
 245         }
 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, bool kern);
 258
 259 int inet_csk_get_port(struct sock *sk, unsigned short snum);
 260
 261 struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
 262                                      const struct request_sock *req);
 263 struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
 264                                             struct sock *newsk,
 265                                             const struct request_sock *req);
 266
 267 struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
 268                                       struct request_sock *req,
 269                                       struct sock *child);
 270 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 271                                    unsigned long timeout);
 272 struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
 273                                          struct request_sock *req,
 274                                          bool own_req);
 275
 276 static inline void inet_csk_reqsk_queue_added(struct sock *sk)
 277 {
 278         reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
 279 }
 280
 281 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
 282 {
 283         return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
 284 }
 285
 286 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
 287 {
 288         return inet_csk_reqsk_queue_len(sk) >= sk->sk_max_ack_backlog;
 289 }
 290
 291 void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
 292 void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
 293
 294 void inet_csk_destroy_sock(struct sock *sk);
 295 void inet_csk_prepare_forced_close(struct sock *sk);
 296
 297 /*
 298  * LISTEN is a special case for poll..
 299  */
 300 static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
 301 {
 302         return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
 303                         (EPOLLIN | EPOLLRDNORM) : 0;
 304 }
 305
 306 int inet_csk_listen_start(struct sock *sk, int backlog);
 307 void inet_csk_listen_stop(struct sock *sk);
 308
 309 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
 310
 311 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
 312                                char __user *optval, int __user *optlen);
 313 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
 314                                char __user *optval, unsigned int optlen);
 315
 316 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
 317
 318 #define TCP_PINGPONG_THRESH     3
 319
 320 static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
 321 {
 322         inet_csk(sk)->icsk_ack.pingpong = TCP_PINGPONG_THRESH;
 323 }
 324
 325 static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
 326 {
 327         inet_csk(sk)->icsk_ack.pingpong = 0;
 328 }
 329
 330 static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
 331 {
 332         return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
 333 }
 334
 335 static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
 336 {
 337         struct inet_connection_sock *icsk = inet_csk(sk);
 338
 339         if (icsk->icsk_ack.pingpong < U8_MAX)
 340                 icsk->icsk_ack.pingpong++;
 341 }
 342 #endif /* _INET_CONNECTION_SOCK_H */