include/net/inet_connection_sock.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * NET          Generic infrastructure for INET connection oriented protocols.
   4  *
   5  *              Definitions for inet_connection_sock
   6  *
   7  * Authors:     Many people, see the TCP sources
   8  *
   9  *              From code originally in TCP
  10  */
  11 #ifndef _INET_CONNECTION_SOCK_H
  12 #define _INET_CONNECTION_SOCK_H
  13
  14 #include <linux/compiler.h>
  15 #include <linux/string.h>
  16 #include <linux/timer.h>
  17 #include <linux/poll.h>
  18 #include <linux/kernel.h>
  19 #include <linux/sockptr.h>
  20
  21 #include <net/inet_sock.h>
  22 #include <net/request_sock.h>
  23
  24 /* Cancel timers, when they are not required. */
  25 #undef INET_CSK_CLEAR_TIMERS
  26
  27 struct inet_bind_bucket;
  28 struct inet_bind2_bucket;
  29 struct tcp_congestion_ops;
  30
  31 /*
  32  * Pointers to address related TCP functions
  33  * (i.e. things that depend on the address family)
  34  */
  35 struct inet_connection_sock_af_ops {
  36         int         (*queue_xmit)(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
  37         void        (*send_check)(struct sock *sk, struct sk_buff *skb);
  38         int         (*rebuild_header)(struct sock *sk);
  39         void        (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
  40         int         (*conn_request)(struct sock *sk, struct sk_buff *skb);
  41         struct sock *(*syn_recv_sock)(const struct sock *sk, struct sk_buff *skb,
  42                                       struct request_sock *req,
  43                                       struct dst_entry *dst,
  44                                       struct request_sock *req_unhash,
  45                                       bool *own_req);
  46         u16         net_header_len;
  47         u16         sockaddr_len;
  48         int         (*setsockopt)(struct sock *sk, int level, int optname,
  49                                   sockptr_t optval, unsigned 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         void        (*mtu_reduced)(struct sock *sk);
  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_bind2_hash:       Bind node in the bhash2 table
  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_ulp_ops           Pluggable ULP control hook
  68  * @icsk_ulp_data          ULP private data
  69  * @icsk_clean_acked       Clean acked data hook
  70  * @icsk_ca_state:         Congestion control state
  71  * @icsk_retransmits:      Number of unrecovered [RTO] timeouts
  72  * @icsk_pending:          Scheduled timer event
  73  * @icsk_backoff:          Backoff
  74  * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
  75  * @icsk_probes_out:       unanswered 0 window probes
  76  * @icsk_ext_hdr_len:      Network protocol overhead (IP/IPv6 options)
  77  * @icsk_ack:              Delayed ACK control data
  78  * @icsk_mtup;             MTU probing control data
  79  * @icsk_probes_tstamp:    Probe timestamp (cleared by non-zero window ack)
  80  * @icsk_user_timeout:     TCP_USER_TIMEOUT value
  81  */
  82 struct inet_connection_sock {
  83         /* inet_sock has to be the first member! */
  84         struct inet_sock          icsk_inet;
  85         struct request_sock_queue icsk_accept_queue;
  86         struct inet_bind_bucket   *icsk_bind_hash;
  87         struct inet_bind2_bucket  *icsk_bind2_hash;
  88         unsigned long             icsk_timeout;
  89         struct timer_list         icsk_retransmit_timer;
  90         struct timer_list         icsk_delack_timer;
  91         __u32                     icsk_rto;
  92         __u32                     icsk_rto_min;
  93         __u32                     icsk_delack_max;
  94         __u32                     icsk_pmtu_cookie;
  95         const struct tcp_congestion_ops *icsk_ca_ops;
  96         const struct inet_connection_sock_af_ops *icsk_af_ops;
  97         const struct tcp_ulp_ops  *icsk_ulp_ops;
  98         void __rcu                *icsk_ulp_data;
  99         void (*icsk_clean_acked)(struct sock *sk, u32 acked_seq);
 100         unsigned int              (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
 101         __u8                      icsk_ca_state:5,
 102                                   icsk_ca_initialized:1,
 103                                   icsk_ca_setsockopt:1,
 104                                   icsk_ca_dst_locked:1;
 105         __u8                      icsk_retransmits;
 106         __u8                      icsk_pending;
 107         __u8                      icsk_backoff;
 108         __u8                      icsk_syn_retries;
 109         __u8                      icsk_probes_out;
 110         __u16                     icsk_ext_hdr_len;
 111         struct {
 112                 __u8              pending;       /* ACK is pending                         */
 113                 __u8              quick;         /* Scheduled number of quick acks         */
 114                 __u8              pingpong;      /* The session is interactive             */
 115                 __u8              retry;         /* Number of attempts                     */
 116                 #define ATO_BITS 8
 117                 __u32             ato:ATO_BITS,  /* Predicted tick of soft clock           */
 118                                   lrcv_flowlabel:20, /* last received ipv6 flowlabel       */
 119                                   unused:4;
 120                 unsigned long     timeout;       /* Currently scheduled timeout            */
 121                 __u32             lrcvtime;      /* timestamp of last received data packet */
 122                 __u16             last_seg_size; /* Size of last incoming segment          */
 123                 __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */
 124         } icsk_ack;
 125         struct {
 126                 /* Range of MTUs to search */
 127                 int               search_high;
 128                 int               search_low;
 129
 130                 /* Information on the current probe. */
 131                 u32               probe_size:31,
 132                 /* Is the MTUP feature enabled for this connection? */
 133                                   enabled:1;
 134
 135                 u32               probe_timestamp;
 136         } icsk_mtup;
 137         u32                       icsk_probes_tstamp;
 138         u32                       icsk_user_timeout;
 139
 140         u64                       icsk_ca_priv[104 / sizeof(u64)];
 141 #define ICSK_CA_PRIV_SIZE         sizeof_field(struct inet_connection_sock, icsk_ca_priv)
 142 };
 143
 144 #define ICSK_TIME_RETRANS       1       /* Retransmit timer */
 145 #define ICSK_TIME_DACK          2       /* Delayed ack timer */
 146 #define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
 147 #define ICSK_TIME_LOSS_PROBE    5       /* Tail loss probe timer */
 148 #define ICSK_TIME_REO_TIMEOUT   6       /* Reordering timer */
 149
 150 #define inet_csk(ptr) container_of_const(ptr, struct inet_connection_sock, icsk_inet.sk)
 151
 152 static inline void *inet_csk_ca(const struct sock *sk)
 153 {
 154         return (void *)inet_csk(sk)->icsk_ca_priv;
 155 }
 156
 157 struct sock *inet_csk_clone_lock(const struct sock *sk,
 158                                  const struct request_sock *req,
 159                                  const gfp_t priority);
 160
 161 enum inet_csk_ack_state_t {
 162         ICSK_ACK_SCHED  = 1,
 163         ICSK_ACK_TIMER  = 2,
 164         ICSK_ACK_PUSHED = 4,
 165         ICSK_ACK_PUSHED2 = 8,
 166         ICSK_ACK_NOW = 16,      /* Send the next ACK immediately (once) */
 167         ICSK_ACK_NOMEM = 32,
 168 };
 169
 170 void inet_csk_init_xmit_timers(struct sock *sk,
 171                                void (*retransmit_handler)(struct timer_list *),
 172                                void (*delack_handler)(struct timer_list *),
 173                                void (*keepalive_handler)(struct timer_list *));
 174 void inet_csk_clear_xmit_timers(struct sock *sk);
 175 void inet_csk_clear_xmit_timers_sync(struct sock *sk);
 176
 177 static inline void inet_csk_schedule_ack(struct sock *sk)
 178 {
 179         inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
 180 }
 181
 182 static inline int inet_csk_ack_scheduled(const struct sock *sk)
 183 {
 184         return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
 185 }
 186
 187 static inline void inet_csk_delack_init(struct sock *sk)
 188 {
 189         memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
 190 }
 191
 192 void inet_csk_delete_keepalive_timer(struct sock *sk);
 193 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
 194
 195 static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
 196 {
 197         struct inet_connection_sock *icsk = inet_csk(sk);
 198
 199         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 200                 smp_store_release(&icsk->icsk_pending, 0);
 201 #ifdef INET_CSK_CLEAR_TIMERS
 202                 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 203 #endif
 204         } else if (what == ICSK_TIME_DACK) {
 205                 smp_store_release(&icsk->icsk_ack.pending, 0);
 206                 icsk->icsk_ack.retry = 0;
 207 #ifdef INET_CSK_CLEAR_TIMERS
 208                 sk_stop_timer(sk, &icsk->icsk_delack_timer);
 209 #endif
 210         } else {
 211                 pr_debug("inet_csk BUG: unknown timer value\n");
 212         }
 213 }
 214
 215 /*
 216  *      Reset the retransmission timer
 217  */
 218 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
 219                                              unsigned long when,
 220                                              const unsigned long max_when)
 221 {
 222         struct inet_connection_sock *icsk = inet_csk(sk);
 223
 224         if (when > max_when) {
 225                 pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
 226                          sk, what, when, (void *)_THIS_IP_);
 227                 when = max_when;
 228         }
 229
 230         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
 231             what == ICSK_TIME_LOSS_PROBE || what == ICSK_TIME_REO_TIMEOUT) {
 232                 smp_store_release(&icsk->icsk_pending, what);
 233                 icsk->icsk_timeout = jiffies + when;
 234                 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
 235         } else if (what == ICSK_TIME_DACK) {
 236                 smp_store_release(&icsk->icsk_ack.pending,
 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         } else {
 241                 pr_debug("inet_csk BUG: unknown timer value\n");
 242         }
 243 }
 244
 245 static inline unsigned long
 246 inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
 247                      unsigned long max_when)
 248 {
 249         u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
 250
 251         return (unsigned long)min_t(u64, when, max_when);
 252 }
 253
 254 struct sock *inet_csk_accept(struct sock *sk, struct proto_accept_arg *arg);
 255
 256 int inet_csk_get_port(struct sock *sk, unsigned short snum);
 257
 258 struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
 259                                      const struct request_sock *req);
 260 struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
 261                                             struct sock *newsk,
 262                                             const struct request_sock *req);
 263
 264 struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
 265                                       struct request_sock *req,
 266                                       struct sock *child);
 267 bool inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 268                                    unsigned long timeout);
 269 struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
 270                                          struct request_sock *req,
 271                                          bool own_req);
 272
 273 static inline void inet_csk_reqsk_queue_added(struct sock *sk)
 274 {
 275         reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
 276 }
 277
 278 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
 279 {
 280         return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
 281 }
 282
 283 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
 284 {
 285         return inet_csk_reqsk_queue_len(sk) >= READ_ONCE(sk->sk_max_ack_backlog);
 286 }
 287
 288 bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
 289 void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
 290
 291 static inline unsigned long
 292 reqsk_timeout(struct request_sock *req, unsigned long max_timeout)
 293 {
 294         u64 timeout = (u64)req->timeout << req->num_timeout;
 295
 296         return (unsigned long)min_t(u64, timeout, max_timeout);
 297 }
 298
 299 static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk)
 300 {
 301         /* The below has to be done to allow calling inet_csk_destroy_sock */
 302         sock_set_flag(sk, SOCK_DEAD);
 303         this_cpu_inc(*sk->sk_prot->orphan_count);
 304 }
 305
 306 void inet_csk_destroy_sock(struct sock *sk);
 307 void inet_csk_prepare_forced_close(struct sock *sk);
 308
 309 /*
 310  * LISTEN is a special case for poll..
 311  */
 312 static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
 313 {
 314         return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
 315                         (EPOLLIN | EPOLLRDNORM) : 0;
 316 }
 317
 318 int inet_csk_listen_start(struct sock *sk);
 319 void inet_csk_listen_stop(struct sock *sk);
 320
 321 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
 322
 323 /* update the fast reuse flag when adding a socket */
 324 void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
 325                                struct sock *sk);
 326
 327 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
 328
 329 static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
 330 {
 331         inet_csk(sk)->icsk_ack.pingpong =
 332                 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pingpong_thresh);
 333 }
 334
 335 static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
 336 {
 337         inet_csk(sk)->icsk_ack.pingpong = 0;
 338 }
 339
 340 static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
 341 {
 342         return inet_csk(sk)->icsk_ack.pingpong >=
 343                READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pingpong_thresh);
 344 }
 345
 346 static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
 347 {
 348         struct inet_connection_sock *icsk = inet_csk(sk);
 349
 350         if (icsk->icsk_ack.pingpong < U8_MAX)
 351                 icsk->icsk_ack.pingpong++;
 352 }
 353
 354 static inline bool inet_csk_has_ulp(const struct sock *sk)
 355 {
 356         return inet_test_bit(IS_ICSK, sk) && !!inet_csk(sk)->icsk_ulp_ops;
 357 }
 358
 359 static inline void inet_init_csk_locks(struct sock *sk)
 360 {
 361         struct inet_connection_sock *icsk = inet_csk(sk);
 362
 363         spin_lock_init(&icsk->icsk_accept_queue.rskq_lock);
 364         spin_lock_init(&icsk->icsk_accept_queue.fastopenq.lock);
 365 }
 366
 367 #endif /* _INET_CONNECTION_SOCK_H */