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 inet_bind2_bucket;
29struct tcp_congestion_ops;
30
31/*
32 * Pointers to address related TCP functions
33 * (i.e. things that depend on the address family)
34 */
35struct 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 */
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 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
150static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
151{
152 return (struct inet_connection_sock *)sk;
153}
154
155static inline void *inet_csk_ca(const struct sock *sk)
156{
157 return (void *)inet_csk(sk)->icsk_ca_priv;
158}
159
160struct sock *inet_csk_clone_lock(const struct sock *sk,
161 const struct request_sock *req,
162 const gfp_t priority);
163
164enum inet_csk_ack_state_t {
165 ICSK_ACK_SCHED = 1,
166 ICSK_ACK_TIMER = 2,
167 ICSK_ACK_PUSHED = 4,
168 ICSK_ACK_PUSHED2 = 8,
169 ICSK_ACK_NOW = 16, /* Send the next ACK immediately (once) */
170 ICSK_ACK_NOMEM = 32,
171};
172
173void inet_csk_init_xmit_timers(struct sock *sk,
174 void (*retransmit_handler)(struct timer_list *),
175 void (*delack_handler)(struct timer_list *),
176 void (*keepalive_handler)(struct timer_list *));
177void inet_csk_clear_xmit_timers(struct sock *sk);
178void inet_csk_clear_xmit_timers_sync(struct sock *sk);
179
180static inline void inet_csk_schedule_ack(struct sock *sk)
181{
182 inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
183}
184
185static inline int inet_csk_ack_scheduled(const struct sock *sk)
186{
187 return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
188}
189
190static inline void inet_csk_delack_init(struct sock *sk)
191{
192 memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
193}
194
195void inet_csk_delete_keepalive_timer(struct sock *sk);
196void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
197
198static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
199{
200 struct inet_connection_sock *icsk = inet_csk(sk);
201
202 if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
203 icsk->icsk_pending = 0;
204#ifdef INET_CSK_CLEAR_TIMERS
205 sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
206#endif
207 } else if (what == ICSK_TIME_DACK) {
208 icsk->icsk_ack.pending = 0;
209 icsk->icsk_ack.retry = 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 */
221static 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_LOSS_PROBE || what == ICSK_TIME_REO_TIMEOUT) {
235 icsk->icsk_pending = what;
236 icsk->icsk_timeout = jiffies + when;
237 sk_reset_timer(sk, timer: &icsk->icsk_retransmit_timer, expires: icsk->icsk_timeout);
238 } else if (what == ICSK_TIME_DACK) {
239 icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
240 icsk->icsk_ack.timeout = jiffies + when;
241 sk_reset_timer(sk, timer: &icsk->icsk_delack_timer, expires: icsk->icsk_ack.timeout);
242 } else {
243 pr_debug("inet_csk BUG: unknown timer value\n");
244 }
245}
246
247static inline unsigned long
248inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
249 unsigned long max_when)
250{
251 u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
252
253 return (unsigned long)min_t(u64, when, max_when);
254}
255
256struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern);
257
258int inet_csk_get_port(struct sock *sk, unsigned short snum);
259
260struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
261 const struct request_sock *req);
262struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
263 struct sock *newsk,
264 const struct request_sock *req);
265
266struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
267 struct request_sock *req,
268 struct sock *child);
269void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
270 unsigned long timeout);
271struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
272 struct request_sock *req,
273 bool own_req);
274
275static inline void inet_csk_reqsk_queue_added(struct sock *sk)
276{
277 reqsk_queue_added(queue: &inet_csk(sk)->icsk_accept_queue);
278}
279
280static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
281{
282 return reqsk_queue_len(queue: &inet_csk(sk)->icsk_accept_queue);
283}
284
285static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
286{
287 return inet_csk_reqsk_queue_len(sk) >= sk->sk_max_ack_backlog;
288}
289
290bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
291void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
292
293static inline unsigned long
294reqsk_timeout(struct request_sock *req, unsigned long max_timeout)
295{
296 u64 timeout = (u64)req->timeout << req->num_timeout;
297
298 return (unsigned long)min_t(u64, timeout, max_timeout);
299}
300
301static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk)
302{
303 /* The below has to be done to allow calling inet_csk_destroy_sock */
304 sock_set_flag(sk, flag: SOCK_DEAD);
305 this_cpu_inc(*sk->sk_prot->orphan_count);
306}
307
308void inet_csk_destroy_sock(struct sock *sk);
309void inet_csk_prepare_forced_close(struct sock *sk);
310
311/*
312 * LISTEN is a special case for poll..
313 */
314static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
315{
316 return !reqsk_queue_empty(queue: &inet_csk(sk)->icsk_accept_queue) ?
317 (EPOLLIN | EPOLLRDNORM) : 0;
318}
319
320int inet_csk_listen_start(struct sock *sk);
321void inet_csk_listen_stop(struct sock *sk);
322
323void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
324
325/* update the fast reuse flag when adding a socket */
326void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
327 struct sock *sk);
328
329struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
330
331static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
332{
333 inet_csk(sk)->icsk_ack.pingpong =
334 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pingpong_thresh);
335}
336
337static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
338{
339 inet_csk(sk)->icsk_ack.pingpong = 0;
340}
341
342static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
343{
344 return inet_csk(sk)->icsk_ack.pingpong >=
345 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pingpong_thresh);
346}
347
348static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
349{
350 struct inet_connection_sock *icsk = inet_csk(sk);
351
352 if (icsk->icsk_ack.pingpong < U8_MAX)
353 icsk->icsk_ack.pingpong++;
354}
355
356static inline bool inet_csk_has_ulp(const struct sock *sk)
357{
358 return inet_test_bit(IS_ICSK, sk) && !!inet_csk(sk)->icsk_ulp_ops;
359}
360
361static inline void inet_init_csk_locks(struct sock *sk)
362{
363 struct inet_connection_sock *icsk = inet_csk(sk);
364
365 spin_lock_init(&icsk->icsk_accept_queue.rskq_lock);
366 spin_lock_init(&icsk->icsk_accept_queue.fastopenq.lock);
367}
368
369#endif /* _INET_CONNECTION_SOCK_H */
370

source code of linux/include/net/inet_connection_sock.h