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
  20#include <net/inet_sock.h>
  21#include <net/request_sock.h>
  22
  23/* Cancel timers, when they are not required. */
  24#undef INET_CSK_CLEAR_TIMERS
  25
  26struct inet_bind_bucket;
  27struct tcp_congestion_ops;
  28
  29/*
  30 * Pointers to address related TCP functions
  31 * (i.e. things that depend on the address family)
  32 */
  33struct inet_connection_sock_af_ops {
  34        int         (*queue_xmit)(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
  35        void        (*send_check)(struct sock *sk, struct sk_buff *skb);
  36        int         (*rebuild_header)(struct sock *sk);
  37        void        (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
  38        int         (*conn_request)(struct sock *sk, struct sk_buff *skb);
  39        struct sock *(*syn_recv_sock)(const struct sock *sk, struct sk_buff *skb,
  40                                      struct request_sock *req,
  41                                      struct dst_entry *dst,
  42                                      struct request_sock *req_unhash,
  43                                      bool *own_req);
  44        u16         net_header_len;
  45        u16         net_frag_header_len;
  46        u16         sockaddr_len;
  47        int         (*setsockopt)(struct sock *sk, int level, int optname,
  48                                  char __user *optval, unsigned int optlen);
  49        int         (*getsockopt)(struct sock *sk, int level, int optname,
  50                                  char __user *optval, int __user *optlen);
  51#ifdef CONFIG_COMPAT
  52        int         (*compat_setsockopt)(struct sock *sk,
  53                                int level, int optname,
  54                                char __user *optval, unsigned int optlen);
  55        int         (*compat_getsockopt)(struct sock *sk,
  56                                int level, int optname,
  57                                char __user *optval, int __user *optlen);
  58#endif
  59        void        (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
  60        void        (*mtu_reduced)(struct sock *sk);
  61};
  62
  63/** inet_connection_sock - INET connection oriented sock
  64 *
  65 * @icsk_accept_queue:     FIFO of established children
  66 * @icsk_bind_hash:        Bind node
  67 * @icsk_timeout:          Timeout
  68 * @icsk_retransmit_timer: Resend (no ack)
  69 * @icsk_rto:              Retransmit timeout
  70 * @icsk_pmtu_cookie       Last pmtu seen by socket
  71 * @icsk_ca_ops            Pluggable congestion control hook
  72 * @icsk_af_ops            Operations which are AF_INET{4,6} specific
  73 * @icsk_ulp_ops           Pluggable ULP control hook
  74 * @icsk_ulp_data          ULP private data
  75 * @icsk_clean_acked       Clean acked data hook
  76 * @icsk_listen_portaddr_node   hash to the portaddr listener hashtable
  77 * @icsk_ca_state:         Congestion control state
  78 * @icsk_retransmits:      Number of unrecovered [RTO] timeouts
  79 * @icsk_pending:          Scheduled timer event
  80 * @icsk_backoff:          Backoff
  81 * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
  82 * @icsk_probes_out:       unanswered 0 window probes
  83 * @icsk_ext_hdr_len:      Network protocol overhead (IP/IPv6 options)
  84 * @icsk_ack:              Delayed ACK control data
  85 * @icsk_mtup;             MTU probing control data
  86 */
  87struct inet_connection_sock {
  88        /* inet_sock has to be the first member! */
  89        struct inet_sock          icsk_inet;
  90        struct request_sock_queue icsk_accept_queue;
  91        struct inet_bind_bucket   *icsk_bind_hash;
  92        unsigned long             icsk_timeout;
  93        struct timer_list         icsk_retransmit_timer;
  94        struct timer_list         icsk_delack_timer;
  95        __u32                     icsk_rto;
  96        __u32                     icsk_pmtu_cookie;
  97        const struct tcp_congestion_ops *icsk_ca_ops;
  98        const struct inet_connection_sock_af_ops *icsk_af_ops;
  99        const struct tcp_ulp_ops  *icsk_ulp_ops;
 100        void                      *icsk_ulp_data;
 101        void (*icsk_clean_acked)(struct sock *sk, u32 acked_seq);
 102        struct hlist_node         icsk_listen_portaddr_node;
 103        unsigned int              (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
 104        __u8                      icsk_ca_state:6,
 105                                  icsk_ca_setsockopt:1,
 106                                  icsk_ca_dst_locked:1;
 107        __u8                      icsk_retransmits;
 108        __u8                      icsk_pending;
 109        __u8                      icsk_backoff;
 110        __u8                      icsk_syn_retries;
 111        __u8                      icsk_probes_out;
 112        __u16                     icsk_ext_hdr_len;
 113        struct {
 114                __u8              pending;       /* ACK is pending                         */
 115                __u8              quick;         /* Scheduled number of quick acks         */
 116                __u8              pingpong;      /* The session is interactive             */
 117                __u8              blocked;       /* Delayed ACK was blocked by socket lock */
 118                __u32             ato;           /* Predicted tick of soft clock           */
 119                unsigned long     timeout;       /* Currently scheduled timeout            */
 120                __u32             lrcvtime;      /* timestamp of last received data packet */
 121                __u16             last_seg_size; /* Size of last incoming segment          */
 122                __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */
 123        } icsk_ack;
 124        struct {
 125                int               enabled;
 126
 127                /* Range of MTUs to search */
 128                int               search_high;
 129                int               search_low;
 130
 131                /* Information on the current probe. */
 132                int               probe_size;
 133
 134                u32               probe_timestamp;
 135        } icsk_mtup;
 136        u32                       icsk_user_timeout;
 137
 138        u64                       icsk_ca_priv[104 / sizeof(u64)];
 139#define ICSK_CA_PRIV_SIZE      (13 * sizeof(u64))
 140};
 141
 142#define ICSK_TIME_RETRANS       1       /* Retransmit timer */
 143#define ICSK_TIME_DACK          2       /* Delayed ack timer */
 144#define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
 145#define ICSK_TIME_EARLY_RETRANS 4       /* Early retransmit timer */
 146#define ICSK_TIME_LOSS_PROBE    5       /* Tail loss probe timer */
 147#define ICSK_TIME_REO_TIMEOUT   6       /* Reordering timer */
 148
 149static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
 150{
 151        return (struct inet_connection_sock *)sk;
 152}
 153
 154static inline void *inet_csk_ca(const struct sock *sk)
 155{
 156        return (void *)inet_csk(sk)->icsk_ca_priv;
 157}
 158
 159struct sock *inet_csk_clone_lock(const struct sock *sk,
 160                                 const struct request_sock *req,
 161                                 const gfp_t priority);
 162
 163enum inet_csk_ack_state_t {
 164        ICSK_ACK_SCHED  = 1,
 165        ICSK_ACK_TIMER  = 2,
 166        ICSK_ACK_PUSHED = 4,
 167        ICSK_ACK_PUSHED2 = 8,
 168        ICSK_ACK_NOW = 16       /* Send the next ACK immediately (once) */
 169};
 170
 171void inet_csk_init_xmit_timers(struct sock *sk,
 172                               void (*retransmit_handler)(struct timer_list *),
 173                               void (*delack_handler)(struct timer_list *),
 174                               void (*keepalive_handler)(struct timer_list *));
 175void inet_csk_clear_xmit_timers(struct sock *sk);
 176
 177static inline void inet_csk_schedule_ack(struct sock *sk)
 178{
 179        inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
 180}
 181
 182static inline int inet_csk_ack_scheduled(const struct sock *sk)
 183{
 184        return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
 185}
 186
 187static 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
 192void inet_csk_delete_keepalive_timer(struct sock *sk);
 193void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
 194
 195static 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                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                icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
 206#ifdef INET_CSK_CLEAR_TIMERS
 207                sk_stop_timer(sk, &icsk->icsk_delack_timer);
 208#endif
 209        } else {
 210                pr_debug("inet_csk BUG: unknown timer value\n");
 211        }
 212}
 213
 214/*
 215 *      Reset the retransmission timer
 216 */
 217static 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                pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
 225                         sk, what, when, (void *)_THIS_IP_);
 226                when = max_when;
 227        }
 228
 229        if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
 230            what == ICSK_TIME_EARLY_RETRANS || what == ICSK_TIME_LOSS_PROBE ||
 231            what == ICSK_TIME_REO_TIMEOUT) {
 232                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                icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
 237                icsk->icsk_ack.timeout = jiffies + when;
 238                sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
 239        } else {
 240                pr_debug("inet_csk BUG: unknown timer value\n");
 241        }
 242}
 243
 244static inline unsigned long
 245inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
 246                     unsigned long max_when)
 247{
 248        u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
 249
 250        return (unsigned long)min_t(u64, when, max_when);
 251}
 252
 253struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern);
 254
 255int inet_csk_get_port(struct sock *sk, unsigned short snum);
 256
 257struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
 258                                     const struct request_sock *req);
 259struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
 260                                            struct sock *newsk,
 261                                            const struct request_sock *req);
 262
 263struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
 264                                      struct request_sock *req,
 265                                      struct sock *child);
 266void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 267                                   unsigned long timeout);
 268struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
 269                                         struct request_sock *req,
 270                                         bool own_req);
 271
 272static inline void inet_csk_reqsk_queue_added(struct sock *sk)
 273{
 274        reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
 275}
 276
 277static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
 278{
 279        return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
 280}
 281
 282static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
 283{
 284        return inet_csk_reqsk_queue_len(sk) >= sk->sk_max_ack_backlog;
 285}
 286
 287void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
 288void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
 289
 290void inet_csk_destroy_sock(struct sock *sk);
 291void inet_csk_prepare_forced_close(struct sock *sk);
 292
 293/*
 294 * LISTEN is a special case for poll..
 295 */
 296static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
 297{
 298        return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
 299                        (EPOLLIN | EPOLLRDNORM) : 0;
 300}
 301
 302int inet_csk_listen_start(struct sock *sk, int backlog);
 303void inet_csk_listen_stop(struct sock *sk);
 304
 305void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
 306
 307int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
 308                               char __user *optval, int __user *optlen);
 309int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
 310                               char __user *optval, unsigned int optlen);
 311
 312struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
 313
 314#define TCP_PINGPONG_THRESH     3
 315
 316static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
 317{
 318        inet_csk(sk)->icsk_ack.pingpong = TCP_PINGPONG_THRESH;
 319}
 320
 321static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
 322{
 323        inet_csk(sk)->icsk_ack.pingpong = 0;
 324}
 325
 326static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
 327{
 328        return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
 329}
 330
 331static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
 332{
 333        struct inet_connection_sock *icsk = inet_csk(sk);
 334
 335        if (icsk->icsk_ack.pingpong < U8_MAX)
 336                icsk->icsk_ack.pingpong++;
 337}
 338#endif /* _INET_CONNECTION_SOCK_H */
 339