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_ca_state: Congestion control state
70 * @icsk_retransmits: Number of unrecovered [RTO] timeouts
71 * @icsk_pending: Scheduled timer event
72 * @icsk_backoff: Backoff
73 * @icsk_syn_retries: Number of allowed SYN (or equivalent) retries
74 * @icsk_probes_out: unanswered 0 window probes
75 * @icsk_ext_hdr_len: Network protocol overhead (IP/IPv6 options)
76 * @icsk_ack: Delayed ACK control data
77 * @icsk_mtup; MTU probing control data
78 * @icsk_probes_tstamp: Probe timestamp (cleared by non-zero window ack)
79 * @icsk_user_timeout: TCP_USER_TIMEOUT value
80 */
81struct inet_connection_sock {
82 /* inet_sock has to be the first member! */
83 struct inet_sock icsk_inet;
84 struct request_sock_queue icsk_accept_queue;
85 struct inet_bind_bucket *icsk_bind_hash;
86 unsigned long icsk_timeout;
87 struct timer_list icsk_retransmit_timer;
88 struct timer_list icsk_delack_timer;
89 __u32 icsk_rto;
90 __u32 icsk_rto_min;
91 __u32 icsk_delack_max;
92 __u32 icsk_pmtu_cookie;
93 const struct tcp_congestion_ops *icsk_ca_ops;
94 const struct inet_connection_sock_af_ops *icsk_af_ops;
95 const struct tcp_ulp_ops *icsk_ulp_ops;
96 void __rcu *icsk_ulp_data;
97 void (*icsk_clean_acked)(struct sock *sk, u32 acked_seq);
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 /* Range of MTUs to search */
122 int search_high;
123 int search_low;
124
125 /* Information on the current probe. */
126 u32 probe_size:31,
127 /* Is the MTUP feature enabled for this connection? */
128 enabled:1;
129
130 u32 probe_timestamp;
131 } icsk_mtup;
132 u32 icsk_probes_tstamp;
133 u32 icsk_user_timeout;
134
135 u64 icsk_ca_priv[104 / sizeof(u64)];
136#define ICSK_CA_PRIV_SIZE sizeof_field(struct inet_connection_sock, icsk_ca_priv)
137};
138
139#define ICSK_TIME_RETRANS 1 /* Retransmit timer */
140#define ICSK_TIME_DACK 2 /* Delayed ack timer */
141#define ICSK_TIME_PROBE0 3 /* Zero window probe timer */
142#define ICSK_TIME_LOSS_PROBE 5 /* Tail loss probe timer */
143#define ICSK_TIME_REO_TIMEOUT 6 /* Reordering timer */
144
145static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
146{
147 return (struct inet_connection_sock *)sk;
148}
149
150static inline void *inet_csk_ca(const struct sock *sk)
151{
152 return (void *)inet_csk(sk)->icsk_ca_priv;
153}
154
155struct sock *inet_csk_clone_lock(const struct sock *sk,
156 const struct request_sock *req,
157 const gfp_t priority);
158
159enum 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
167void 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 *));
171void inet_csk_clear_xmit_timers(struct sock *sk);
172
173static inline void inet_csk_schedule_ack(struct sock *sk)
174{
175 inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
176}
177
178static inline int inet_csk_ack_scheduled(const struct sock *sk)
179{
180 return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
181}
182
183static 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
188void inet_csk_delete_keepalive_timer(struct sock *sk);
189void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
190
191static 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 */
214static 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_LOSS_PROBE || what == ICSK_TIME_REO_TIMEOUT) {
228 icsk->icsk_pending = what;
229 icsk->icsk_timeout = jiffies + when;
230 sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
231 } else if (what == ICSK_TIME_DACK) {
232 icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
233 icsk->icsk_ack.timeout = jiffies + when;
234 sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
235 } else {
236 pr_debug("inet_csk BUG: unknown timer value\n");
237 }
238}
239
240static inline unsigned long
241inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
242 unsigned long max_when)
243{
244 u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
245
246 return (unsigned long)min_t(u64, when, max_when);
247}
248
249struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern);
250
251int inet_csk_get_port(struct sock *sk, unsigned short snum);
252
253struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
254 const struct request_sock *req);
255struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
256 struct sock *newsk,
257 const struct request_sock *req);
258
259struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
260 struct request_sock *req,
261 struct sock *child);
262void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
263 unsigned long timeout);
264struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
265 struct request_sock *req,
266 bool own_req);
267
268static inline void inet_csk_reqsk_queue_added(struct sock *sk)
269{
270 reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
271}
272
273static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
274{
275 return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
276}
277
278static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
279{
280 return inet_csk_reqsk_queue_len(sk) >= sk->sk_max_ack_backlog;
281}
282
283bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
284void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
285
286static inline unsigned long
287reqsk_timeout(struct request_sock *req, unsigned long max_timeout)
288{
289 u64 timeout = (u64)req->timeout << req->num_timeout;
290
291 return (unsigned long)min_t(u64, timeout, max_timeout);
292}
293
294static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk)
295{
296 /* The below has to be done to allow calling inet_csk_destroy_sock */
297 sock_set_flag(sk, SOCK_DEAD);
298 this_cpu_inc(*sk->sk_prot->orphan_count);
299}
300
301void inet_csk_destroy_sock(struct sock *sk);
302void inet_csk_prepare_forced_close(struct sock *sk);
303
304/*
305 * LISTEN is a special case for poll..
306 */
307static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
308{
309 return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
310 (EPOLLIN | EPOLLRDNORM) : 0;
311}
312
313int inet_csk_listen_start(struct sock *sk);
314void inet_csk_listen_stop(struct sock *sk);
315
316void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
317
318/* update the fast reuse flag when adding a socket */
319void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
320 struct sock *sk);
321
322struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
323
324#define TCP_PINGPONG_THRESH 1
325
326static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
327{
328 inet_csk(sk)->icsk_ack.pingpong = TCP_PINGPONG_THRESH;
329}
330
331static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
332{
333 inet_csk(sk)->icsk_ack.pingpong = 0;
334}
335
336static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
337{
338 return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
339}
340
341static inline bool inet_csk_has_ulp(struct sock *sk)
342{
343 return inet_sk(sk)->is_icsk && !!inet_csk(sk)->icsk_ulp_ops;
344}
345
346#endif /* _INET_CONNECTION_SOCK_H */
347

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