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 tcp_congestion_ops;
  29
  30 /*
  31  * Pointers to address related TCP functions
  32  * (i.e. things that depend on the address family)
  33  */
  34 struct 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  */
  80 struct inet_connection_sock {
  81         /* inet_sock has to be the first member! */
  82         struct inet_sock          icsk_inet;
  83         struct request_sock_queue icsk_accept_queue;
  84         struct inet_bind_bucket   *icsk_bind_hash;
  85         unsigned long             icsk_timeout;
  86         struct timer_list         icsk_retransmit_timer;
  87         struct timer_list         icsk_delack_timer;
  88         __u32                     icsk_rto;
  89         __u32                     icsk_rto_min;
  90         __u32                     icsk_delack_max;
  91         __u32                     icsk_pmtu_cookie;
  92         const struct tcp_congestion_ops *icsk_ca_ops;
  93         const struct inet_connection_sock_af_ops *icsk_af_ops;
  94         const struct tcp_ulp_ops  *icsk_ulp_ops;
  95         void __rcu                *icsk_ulp_data;
  96         void (*icsk_clean_acked)(struct sock *sk, u32 acked_seq);
  97         struct hlist_node         icsk_listen_portaddr_node;
  98         unsigned int              (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
  99         __u8                      icsk_ca_state:5,
 100                                   icsk_ca_initialized:1,
 101                                   icsk_ca_setsockopt:1,
 102                                   icsk_ca_dst_locked:1;
 103         __u8                      icsk_retransmits;
 104         __u8                      icsk_pending;
 105         __u8                      icsk_backoff;
 106         __u8                      icsk_syn_retries;
 107         __u8                      icsk_probes_out;
 108         __u16                     icsk_ext_hdr_len;
 109         struct {
 110                 __u8              pending;       /* ACK is pending                         */
 111                 __u8              quick;         /* Scheduled number of quick acks         */
 112                 __u8              pingpong;      /* The session is interactive             */
 113                 __u8              retry;         /* Number of attempts                     */
 114                 __u32             ato;           /* Predicted tick of soft clock           */
 115                 unsigned long     timeout;       /* Currently scheduled timeout            */
 116                 __u32             lrcvtime;      /* timestamp of last received data packet */
 117                 __u16             last_seg_size; /* Size of last incoming segment          */
 118                 __u16             rcv_mss;       /* MSS used for delayed ACK decisions     */
 119         } icsk_ack;
 120         struct {
 121                 int               enabled;
 122
 123                 /* Range of MTUs to search */
 124                 int               search_high;
 125                 int               search_low;
 126
 127                 /* Information on the current probe. */
 128                 int               probe_size;
 129
 130                 u32               probe_timestamp;
 131         } icsk_mtup;
 132         u32                       icsk_user_timeout;
 133
 134         u64                       icsk_ca_priv[104 / sizeof(u64)];
 135 #define ICSK_CA_PRIV_SIZE      (13 * sizeof(u64))
 136 };
 137
 138 #define ICSK_TIME_RETRANS       1       /* Retransmit timer */
 139 #define ICSK_TIME_DACK          2       /* Delayed ack timer */
 140 #define ICSK_TIME_PROBE0        3       /* Zero window probe timer */
 141 #define ICSK_TIME_EARLY_RETRANS 4       /* Early retransmit timer */
 142 #define ICSK_TIME_LOSS_PROBE    5       /* Tail loss probe timer */
 143 #define ICSK_TIME_REO_TIMEOUT   6       /* Reordering timer */
 144
 145 static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
 146 {
 147         return (struct inet_connection_sock *)sk;
 148 }
 149
 150 static inline void *inet_csk_ca(const struct sock *sk)
 151 {
 152         return (void *)inet_csk(sk)->icsk_ca_priv;
 153 }
 154
 155 struct sock *inet_csk_clone_lock(const struct sock *sk,
 156                                  const struct request_sock *req,
 157                                  const gfp_t priority);
 158
 159 enum inet_csk_ack_state_t {
 160         ICSK_ACK_SCHED  = 1,
 161         ICSK_ACK_TIMER  = 2,
 162         ICSK_ACK_PUSHED = 4,
 163         ICSK_ACK_PUSHED2 = 8,
 164         ICSK_ACK_NOW = 16       /* Send the next ACK immediately (once) */
 165 };
 166
 167 void inet_csk_init_xmit_timers(struct sock *sk,
 168                                void (*retransmit_handler)(struct timer_list *),
 169                                void (*delack_handler)(struct timer_list *),
 170                                void (*keepalive_handler)(struct timer_list *));
 171 void inet_csk_clear_xmit_timers(struct sock *sk);
 172
 173 static inline void inet_csk_schedule_ack(struct sock *sk)
 174 {
 175         inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
 176 }
 177
 178 static inline int inet_csk_ack_scheduled(const struct sock *sk)
 179 {
 180         return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
 181 }
 182
 183 static inline void inet_csk_delack_init(struct sock *sk)
 184 {
 185         memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
 186 }
 187
 188 void inet_csk_delete_keepalive_timer(struct sock *sk);
 189 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
 190
 191 static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
 192 {
 193         struct inet_connection_sock *icsk = inet_csk(sk);
 194
 195         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
 196                 icsk->icsk_pending = 0;
 197 #ifdef INET_CSK_CLEAR_TIMERS
 198                 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
 199 #endif
 200         } else if (what == ICSK_TIME_DACK) {
 201                 icsk->icsk_ack.pending = 0;
 202                 icsk->icsk_ack.retry = 0;
 203 #ifdef INET_CSK_CLEAR_TIMERS
 204                 sk_stop_timer(sk, &icsk->icsk_delack_timer);
 205 #endif
 206         } else {
 207                 pr_debug("inet_csk BUG: unknown timer value\n");
 208         }
 209 }
 210
 211 /*
 212  *      Reset the retransmission timer
 213  */
 214 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
 215                                              unsigned long when,
 216                                              const unsigned long max_when)
 217 {
 218         struct inet_connection_sock *icsk = inet_csk(sk);
 219
 220         if (when > max_when) {
 221                 pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
 222                          sk, what, when, (void *)_THIS_IP_);
 223                 when = max_when;
 224         }
 225
 226         if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
 227             what == ICSK_TIME_EARLY_RETRANS || what == ICSK_TIME_LOSS_PROBE ||
 228             what == ICSK_TIME_REO_TIMEOUT) {
 229                 icsk->icsk_pending = what;
 230                 icsk->icsk_timeout = jiffies + when;
 231                 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
 232         } else if (what == ICSK_TIME_DACK) {
 233                 icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
 234                 icsk->icsk_ack.timeout = jiffies + when;
 235                 sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
 236         } else {
 237                 pr_debug("inet_csk BUG: unknown timer value\n");
 238         }
 239 }
 240
 241 static inline unsigned long
 242 inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
 243                      unsigned long max_when)
 244 {
 245         u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
 246
 247         return (unsigned long)min_t(u64, when, max_when);
 248 }
 249
 250 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern);
 251
 252 int inet_csk_get_port(struct sock *sk, unsigned short snum);
 253
 254 struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
 255                                      const struct request_sock *req);
 256 struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
 257                                             struct sock *newsk,
 258                                             const struct request_sock *req);
 259
 260 struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
 261                                       struct request_sock *req,
 262                                       struct sock *child);
 263 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 264                                    unsigned long timeout);
 265 struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
 266                                          struct request_sock *req,
 267                                          bool own_req);
 268
 269 static inline void inet_csk_reqsk_queue_added(struct sock *sk)
 270 {
 271         reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
 272 }
 273
 274 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
 275 {
 276         return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
 277 }
 278
 279 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
 280 {
 281         return inet_csk_reqsk_queue_len(sk) >= sk->sk_max_ack_backlog;
 282 }
 283
 284 void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
 285 void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
 286
 287 static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk)
 288 {
 289         /* The below has to be done to allow calling inet_csk_destroy_sock */
 290         sock_set_flag(sk, SOCK_DEAD);
 291         percpu_counter_inc(sk->sk_prot->orphan_count);
 292 }
 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 /* update the fast reuse flag when adding a socket */
 312 void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
 313                                struct sock *sk);
 314
 315 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
 316
 317 #define TCP_PINGPONG_THRESH     3
 318
 319 static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
 320 {
 321         inet_csk(sk)->icsk_ack.pingpong = TCP_PINGPONG_THRESH;
 322 }
 323
 324 static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
 325 {
 326         inet_csk(sk)->icsk_ack.pingpong = 0;
 327 }
 328
 329 static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
 330 {
 331         return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
 332 }
 333
 334 static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
 335 {
 336         struct inet_connection_sock *icsk = inet_csk(sk);
 337
 338         if (icsk->icsk_ack.pingpong < U8_MAX)
 339                 icsk->icsk_ack.pingpong++;
 340 }
 341
 342 static inline bool inet_csk_has_ulp(struct sock *sk)
 343 {
 344         return inet_sk(sk)->is_icsk && !!inet_csk(sk)->icsk_ulp_ops;
 345 }
 346
 347 #endif /* _INET_CONNECTION_SOCK_H */