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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 int (*setsockopt)(struct sock *sk, int level, int optname,
48 sockptr_t optval, unsigned int optlen);
49 int (*getsockopt)(struct sock *sk, int level, int optname,
50 char __user *optval, int __user *optlen);
51 void (*mtu_reduced)(struct sock *sk);
52};
53
54/** inet_connection_sock - INET connection oriented sock
55 *
56 * @icsk_accept_queue: FIFO of established children
57 * @icsk_bind_hash: Bind node
58 * @icsk_bind2_hash: Bind node in the bhash2 table
59 * @icsk_delack_timer: Delayed ACK timer
60 * @icsk_keepalive_timer: Keepalive timer
61 * @mptcp_tout_timer: mptcp timer
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_ca_state: Congestion control state
69 * @icsk_retransmits: Number of unrecovered [RTO] timeouts
70 * @icsk_pending: Scheduled timer event
71 * @icsk_backoff: Backoff
72 * @icsk_syn_retries: Number of allowed SYN (or equivalent) retries
73 * @icsk_probes_out: unanswered 0 window probes
74 * @icsk_ext_hdr_len: Network protocol overhead (IP/IPv6 options)
75 * @icsk_ack: Delayed ACK control data
76 * @icsk_mtup; MTU probing control data
77 * @icsk_probes_tstamp: Probe timestamp (cleared by non-zero window ack)
78 * @icsk_user_timeout: TCP_USER_TIMEOUT value
79 */
80struct 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 struct inet_bind2_bucket *icsk_bind2_hash;
86 struct timer_list icsk_delack_timer;
87 union {
88 struct timer_list icsk_keepalive_timer;
89 struct timer_list mptcp_tout_timer;
90 };
91 __u32 icsk_rto;
92 __u32 icsk_rto_min;
93 u32 icsk_rto_max;
94 __u32 icsk_delack_max;
95 __u32 icsk_pmtu_cookie;
96 const struct tcp_congestion_ops *icsk_ca_ops;
97 const struct inet_connection_sock_af_ops *icsk_af_ops;
98 const struct tcp_ulp_ops *icsk_ulp_ops;
99 void __rcu *icsk_ulp_data;
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 dst_quick_ack:1, /* cache dst RTAX_QUICKACK */
120 unused:3;
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
150#define inet_csk(ptr) container_of_const(ptr, struct inet_connection_sock, icsk_inet.sk)
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 ICSK_ACK_NOMEM = 32,
168};
169
170void inet_csk_init_xmit_timers(struct sock *sk,
171 void (*retransmit_handler)(struct timer_list *),
172 void (*delack_handler)(struct timer_list *),
173 void (*keepalive_handler)(struct timer_list *));
174void inet_csk_clear_xmit_timers(struct sock *sk);
175void inet_csk_clear_xmit_timers_sync(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
192static inline unsigned long tcp_timeout_expires(const struct sock *sk)
193{
194 return READ_ONCE(sk->tcp_retransmit_timer.expires);
195}
196
197static inline unsigned long
198icsk_delack_timeout(const struct inet_connection_sock *icsk)
199{
200 return READ_ONCE(icsk->icsk_delack_timer.expires);
201}
202
203static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
204{
205 struct inet_connection_sock *icsk = inet_csk(sk);
206
207 if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
208 smp_store_release(&icsk->icsk_pending, 0);
209#ifdef INET_CSK_CLEAR_TIMERS
210 sk_stop_timer(sk, &sk->tcp_retransmit_timer);
211#endif
212 } else if (what == ICSK_TIME_DACK) {
213 smp_store_release(&icsk->icsk_ack.pending, 0);
214 icsk->icsk_ack.retry = 0;
215#ifdef INET_CSK_CLEAR_TIMERS
216 sk_stop_timer(sk, &icsk->icsk_delack_timer);
217#endif
218 } else {
219 pr_debug("inet_csk BUG: unknown timer value\n");
220 }
221}
222
223/*
224 * Reset the retransmission timer
225 */
226static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
227 unsigned long when,
228 const unsigned long max_when)
229{
230 struct inet_connection_sock *icsk = inet_csk(sk);
231
232 if (when > max_when) {
233 pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
234 sk, what, when, (void *)_THIS_IP_);
235 when = max_when;
236 }
237
238 when += jiffies;
239 if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
240 what == ICSK_TIME_LOSS_PROBE || what == ICSK_TIME_REO_TIMEOUT) {
241 smp_store_release(&icsk->icsk_pending, what);
242 sk_reset_timer(sk, &sk->tcp_retransmit_timer, when);
243 } else if (what == ICSK_TIME_DACK) {
244 smp_store_release(&icsk->icsk_ack.pending,
245 icsk->icsk_ack.pending | ICSK_ACK_TIMER);
246 sk_reset_timer(sk, &icsk->icsk_delack_timer, when);
247 } else {
248 pr_debug("inet_csk BUG: unknown timer value\n");
249 }
250}
251
252static inline unsigned long
253inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
254 unsigned long max_when)
255{
256 u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
257
258 return (unsigned long)min_t(u64, when, max_when);
259}
260
261struct sock *inet_csk_accept(struct sock *sk, struct proto_accept_arg *arg);
262
263int inet_csk_get_port(struct sock *sk, unsigned short snum);
264
265struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
266 const struct request_sock *req);
267struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
268 struct sock *newsk,
269 const struct request_sock *req);
270
271struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
272 struct request_sock *req,
273 struct sock *child);
274bool inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req);
275struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
276 struct request_sock *req,
277 bool own_req);
278
279static inline void inet_csk_reqsk_queue_added(struct sock *sk)
280{
281 reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
282}
283
284static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
285{
286 return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
287}
288
289static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
290{
291 return inet_csk_reqsk_queue_len(sk) > READ_ONCE(sk->sk_max_ack_backlog);
292}
293
294bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
295void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
296
297void inet_csk_destroy_sock(struct sock *sk);
298void inet_csk_prepare_for_destroy_sock(struct sock *sk);
299void inet_csk_prepare_forced_close(struct sock *sk);
300
301/*
302 * LISTEN is a special case for poll..
303 */
304static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
305{
306 return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
307 (EPOLLIN | EPOLLRDNORM) : 0;
308}
309
310int inet_csk_listen_start(struct sock *sk);
311void inet_csk_listen_stop(struct sock *sk);
312
313/* update the fast reuse flag when adding a socket */
314void inet_csk_update_fastreuse(const struct sock *sk,
315 struct inet_bind_bucket *tb,
316 struct inet_bind2_bucket *tb2);
317
318struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
319
320static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
321{
322 inet_csk(sk)->icsk_ack.pingpong =
323 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pingpong_thresh);
324}
325
326static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
327{
328 inet_csk(sk)->icsk_ack.pingpong = 0;
329}
330
331static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
332{
333 return inet_csk(sk)->icsk_ack.pingpong >=
334 READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pingpong_thresh);
335}
336
337static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
338{
339 struct inet_connection_sock *icsk = inet_csk(sk);
340
341 if (icsk->icsk_ack.pingpong < U8_MAX)
342 icsk->icsk_ack.pingpong++;
343}
344
345static inline bool inet_csk_has_ulp(const struct sock *sk)
346{
347 return inet_test_bit(IS_ICSK, sk) && !!inet_csk(sk)->icsk_ulp_ops;
348}
349
350static inline void inet_init_csk_locks(struct sock *sk)
351{
352 struct inet_connection_sock *icsk = inet_csk(sk);
353
354 spin_lock_init(&icsk->icsk_accept_queue.rskq_lock);
355 spin_lock_init(&icsk->icsk_accept_queue.fastopenq.lock);
356}
357
358#endif /* _INET_CONNECTION_SOCK_H */