LXR linux/include/net/inet_connection

   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
  27struct inet_bind_bucket;
  28struct tcp_congestion_ops;
  29
  30/*
  31 * Pointers to address related TCP functions
  32 * (i.e. things that depend on the address family)
  33 */
  34struct inet_connection_sock_af_ops {
  35        int         (*queue_xmit)(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
  36        void        (*send_check)(struct sock *sk, struct sk_buff *skb);
  37        int         (*rebuild_header)(struct sock *sk);
  38        void        (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
  39        int         (*conn_request)(struct sock *sk, struct sk_buff *skb);
  40        struct sock *(*syn_recv_sock)(const struct sock *sk, struct sk_buff *skb,
  41                                      struct request_sock *req,
  42                                      struct dst_entry *dst,
  43                                      struct request_sock *req_unhash,
  44                                      bool *own_req);
  45        u16         net_header_len;
  46        u16         net_frag_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_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_ulp_ops           Pluggable ULP control hook
  67 * @icsk_ulp_data          ULP private data
  68 * @icsk_clean_acked       Clean acked data hook
  69 * @icsk_listen_portaddr_node   hash to the portaddr listener hashtable
  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 */
  82struct 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        unsigned long             icsk_timeout;
  88        struct timer_list         icsk_retransmit_timer;
  89        struct timer_list         icsk_delack_timer;
  90        __u32                     icsk_rto;
  91        __u32                     icsk_rto_min;
  92        __u32                     icsk_delack_max;
  93        __u32                     icsk_pmtu_cookie;
  94        const struct tcp_congestion_ops *icsk_ca_ops;
  95        const struct inet_connection_sock_af_ops *icsk_af_ops;
  96        const struct tcp_ulp_ops  *icsk_ulp_ops;
  97        void __rcu                *icsk_ulp_data;
  98        void (*icsk_clean_acked)(struct sock *sk, u32 acked_seq);
  99        struct hlist_node         icsk_listen_portaddr_node;
 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                __u32             ato;           /* Predicted tick of soft clock           */
 117                unsigned long     timeout;       /* Currently scheduled timeout            */
 118                __u32             lrcvtime;      /* timestamp of last received data packet */
 119                __u16             last_seg_size; /* Size of last incoming segment          */
 120                __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */
 121        } icsk_ack;
 122        struct {
 123                /* Range of MTUs to search */
 124                int               search_high;
 125                int               search_low;
 126
 127                /* Information on the current probe. */
 128                u32               probe_size:31,
 129                /* Is the MTUP feature enabled for this connection? */
 130                                  enabled:1;
 131
 132                u32               probe_timestamp;
 133        } icsk_mtup;
 134        u32                       icsk_probes_tstamp;
 135        u32                       icsk_user_timeout;
 136
 137        u64                       icsk_ca_priv[104 / sizeof(u64)];
 138#define ICSK_CA_PRIV_SIZE         sizeof_field(struct inet_connection_sock, icsk_ca_priv)
 139};
 140
 141#define ICSK_TIME_RETRANS       1       /* Retransmit timer */
 142#define ICSK_TIME_DACK          2       /* Delayed ack timer */
 143#define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
 144#define ICSK_TIME_LOSS_PROBE    5       /* Tail loss probe timer */
 145#define ICSK_TIME_REO_TIMEOUT   6       /* Reordering timer */
 146
 147static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
 148{
 149        return (struct inet_connection_sock *)sk;
 150}
 151
 152static inline void *inet_csk_ca(const struct sock *sk)
 153{
 154        return (void *)inet_csk(sk)->icsk_ca_priv;
 155}
 156
 157struct sock *inet_csk_clone_lock(const struct sock *sk,
 158                                 const struct request_sock *req,
 159                                 const gfp_t priority);
 160
 161enum 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};
 168
 169void inet_csk_init_xmit_timers(struct sock *sk,
 170                               void (*retransmit_handler)(struct timer_list *),
 171                               void (*delack_handler)(struct timer_list *),
 172                               void (*keepalive_handler)(struct timer_list *));
 173void inet_csk_clear_xmit_timers(struct sock *sk);
 174
 175static inline void inet_csk_schedule_ack(struct sock *sk)
 176{
 177        inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
 178}
 179
 180static inline int inet_csk_ack_scheduled(const struct sock *sk)
 181{
 182        return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
 183}
 184
 185static inline void inet_csk_delack_init(struct sock *sk)
 186{
 187        memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
 188}
 189
 190void inet_csk_delete_keepalive_timer(struct sock *sk);
 191void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
 192
 193static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
 194{
 195        struct inet_connection_sock *icsk = inet_csk(sk);
 196
 197        if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 198                icsk->icsk_pending = 0;
 199#ifdef INET_CSK_CLEAR_TIMERS
 200                sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 201#endif
 202        } else if (what == ICSK_TIME_DACK) {
 203                icsk->icsk_ack.pending = 0;
 204                icsk->icsk_ack.retry = 0;
 205#ifdef INET_CSK_CLEAR_TIMERS
 206                sk_stop_timer(sk, &icsk->icsk_delack_timer);
 207#endif
 208        } else {
 209                pr_debug("inet_csk BUG: unknown timer value\n");
 210        }
 211}
 212
 213/*
 214 *      Reset the retransmission timer
 215 */
 216static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
 217                                             unsigned long when,
 218                                             const unsigned long max_when)
 219{
 220        struct inet_connection_sock *icsk = inet_csk(sk);
 221
 222        if (when > max_when) {
 223                pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
 224                         sk, what, when, (void *)_THIS_IP_);
 225                when = max_when;
 226        }
 227
 228        if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
 229            what == ICSK_TIME_LOSS_PROBE || what == ICSK_TIME_REO_TIMEOUT) {
 230                icsk->icsk_pending = what;
 231                icsk->icsk_timeout = jiffies + when;
 232                sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
 233        } else if (what == ICSK_TIME_DACK) {
 234                icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
 235                icsk->icsk_ack.timeout = jiffies + when;
 236                sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
 237        } else {
 238                pr_debug("inet_csk BUG: unknown timer value\n");
 239        }
 240}
 241
 242static inline unsigned long
 243inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
 244                     unsigned long max_when)
 245{
 246        u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
 247
 248        return (unsigned long)min_t(u64, when, max_when);
 249}
 250
 251struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern);
 252
 253int inet_csk_get_port(struct sock *sk, unsigned short snum);
 254
 255struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
 256                                     const struct request_sock *req);
 257struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
 258                                            struct sock *newsk,
 259                                            const struct request_sock *req);
 260
 261struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
 262                                      struct request_sock *req,
 263                                      struct sock *child);
 264void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 265                                   unsigned long timeout);
 266struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
 267                                         struct request_sock *req,
 268                                         bool own_req);
 269
 270static inline void inet_csk_reqsk_queue_added(struct sock *sk)
 271{
 272        reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
 273}
 274
 275static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
 276{
 277        return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
 278}
 279
 280static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
 281{
 282        return inet_csk_reqsk_queue_len(sk) >= sk->sk_max_ack_backlog;
 283}
 284
 285bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
 286void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
 287
 288static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk)
 289{
 290        /* The below has to be done to allow calling inet_csk_destroy_sock */
 291        sock_set_flag(sk, SOCK_DEAD);
 292        percpu_counter_inc(sk->sk_prot->orphan_count);
 293}
 294
 295void inet_csk_destroy_sock(struct sock *sk);
 296void inet_csk_prepare_forced_close(struct sock *sk);
 297
 298/*
 299 * LISTEN is a special case for poll..
 300 */
 301static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
 302{
 303        return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
 304                        (EPOLLIN | EPOLLRDNORM) : 0;
 305}
 306
 307int inet_csk_listen_start(struct sock *sk, int backlog);
 308void inet_csk_listen_stop(struct sock *sk);
 309
 310void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
 311
 312/* update the fast reuse flag when adding a socket */
 313void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
 314                               struct sock *sk);
 315
 316struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
 317
 318#define TCP_PINGPONG_THRESH     3
 319
 320static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
 321{
 322        inet_csk(sk)->icsk_ack.pingpong = TCP_PINGPONG_THRESH;
 323}
 324
 325static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
 326{
 327        inet_csk(sk)->icsk_ack.pingpong = 0;
 328}
 329
 330static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
 331{
 332        return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
 333}
 334
 335static 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
 343static inline bool inet_csk_has_ulp(struct sock *sk)
 344{
 345        return inet_sk(sk)->is_icsk && !!inet_csk(sk)->icsk_ulp_ops;
 346}
 347
 348#endif /* _INET_CONNECTION_SOCK_H */
 349