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
 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				      void (*opt_child_init)(struct sock *newsk,
 47							     const struct sock *sk));
 48	u16	    net_header_len;
 49	int	    (*setsockopt)(struct sock *sk, int level, int optname,
 50				  sockptr_t optval, unsigned int optlen);
 51	int	    (*getsockopt)(struct sock *sk, int level, int optname,
 52				  char __user *optval, int __user *optlen);
 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_delack_timer:     Delayed ACK timer
 62 * @icsk_keepalive_timer:  Keepalive timer
 63 * @mptcp_tout_timer: mptcp timer
 64 * @icsk_rto:		   Retransmit timeout
 65 * @icsk_pmtu_cookie	   Last pmtu seen by socket
 66 * @icsk_ca_ops		   Pluggable congestion control hook
 67 * @icsk_af_ops		   Operations which are AF_INET{4,6} specific
 68 * @icsk_ulp_ops	   Pluggable ULP control hook
 69 * @icsk_ulp_data	   ULP private data
 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	struct timer_list	  icsk_delack_timer;
 89	union {
 90		struct timer_list icsk_keepalive_timer;
 91		struct timer_list mptcp_tout_timer;
 92	};
 93	__u32			  icsk_rto;
 94	__u32                     icsk_rto_min;
 95	u32			  icsk_rto_max;
 96	__u32                     icsk_delack_max;
 97	__u32			  icsk_pmtu_cookie;
 98	const struct tcp_congestion_ops *icsk_ca_ops;
 99	const struct inet_connection_sock_af_ops *icsk_af_ops;
100	const struct tcp_ulp_ops  *icsk_ulp_ops;
101	void __rcu		  *icsk_ulp_data;
102	unsigned int		  (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
103	__u8			  icsk_ca_state:5,
104				  icsk_ca_initialized:1,
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		  retry;	 /* Number of attempts			   */
118		#define ATO_BITS 8
119		__u32		  ato:ATO_BITS,	 /* Predicted tick of soft clock	   */
120				  lrcv_flowlabel:20, /* last received ipv6 flowlabel	   */
121				  dst_quick_ack:1, /* cache dst RTAX_QUICKACK		   */
122				  unused:3;
123		__u32		  lrcvtime;	 /* timestamp of last received data packet */
124		__u16		  last_seg_size; /* Size of last incoming segment	   */
125		__u16		  rcv_mss;	 /* MSS used for delayed ACK decisions	   */
126	} icsk_ack;
127	struct {
128		/* Range of MTUs to search */
129		int		  search_high;
130		int		  search_low;
131
132		/* Information on the current probe. */
133		u32		  probe_size:31,
134		/* Is the MTUP feature enabled for this connection? */
135				  enabled:1;
136
137		u32		  probe_timestamp;
138	} icsk_mtup;
139	u32			  icsk_probes_tstamp;
140	u32			  icsk_user_timeout;
141
142	u64			  icsk_ca_priv[104 / sizeof(u64)];
143#define ICSK_CA_PRIV_SIZE	  sizeof_field(struct inet_connection_sock, icsk_ca_priv)
144};
145
146#define ICSK_TIME_RETRANS	1	/* Retransmit timer */
147#define ICSK_TIME_DACK		2	/* Delayed ack timer */
148#define ICSK_TIME_PROBE0	3	/* Zero window probe timer */
149#define ICSK_TIME_LOSS_PROBE	5	/* Tail loss probe timer */
150#define ICSK_TIME_REO_TIMEOUT	6	/* Reordering timer */
151
152#define inet_csk(ptr) container_of_const(ptr, struct inet_connection_sock, icsk_inet.sk)
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	ICSK_ACK_NOMEM = 32,
170};
171
172void inet_csk_init_xmit_timers(struct sock *sk,
173			       void (*retransmit_handler)(struct timer_list *),
174			       void (*delack_handler)(struct timer_list *),
175			       void (*keepalive_handler)(struct timer_list *));
176void inet_csk_clear_xmit_timers(struct sock *sk);
177void inet_csk_clear_xmit_timers_sync(struct sock *sk);
178
179static inline void inet_csk_schedule_ack(struct sock *sk)
180{
181	inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
182}
183
184static inline int inet_csk_ack_scheduled(const struct sock *sk)
185{
186	return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
187}
188
189static inline void inet_csk_delack_init(struct sock *sk)
190{
191	memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
192}
193
194static inline unsigned long tcp_timeout_expires(const struct sock *sk)
195{
196	return READ_ONCE(sk->tcp_retransmit_timer.expires);
197}
198
199static inline unsigned long
200icsk_delack_timeout(const struct inet_connection_sock *icsk)
201{
202	return READ_ONCE(icsk->icsk_delack_timer.expires);
203}
204
205static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
206{
207	struct inet_connection_sock *icsk = inet_csk(sk);
208
209	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
210		smp_store_release(&icsk->icsk_pending, 0);
211#ifdef INET_CSK_CLEAR_TIMERS
212		sk_stop_timer(sk, &sk->tcp_retransmit_timer);
213#endif
214	} else if (what == ICSK_TIME_DACK) {
215		smp_store_release(&icsk->icsk_ack.pending, 0);
216		icsk->icsk_ack.retry = 0;
217#ifdef INET_CSK_CLEAR_TIMERS
218		sk_stop_timer(sk, &icsk->icsk_delack_timer);
219#endif
220	} else {
221		pr_debug("inet_csk BUG: unknown timer value\n");
222	}
223}
224
225/*
226 *	Reset the retransmission timer
227 */
228static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
229					     unsigned long when,
230					     const unsigned long max_when)
231{
232	struct inet_connection_sock *icsk = inet_csk(sk);
233
234	if (when > max_when) {
235		pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
236			 sk, what, when, (void *)_THIS_IP_);
237		when = max_when;
238	}
239
240	when += jiffies;
241	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
242	    what == ICSK_TIME_LOSS_PROBE || what == ICSK_TIME_REO_TIMEOUT) {
243		smp_store_release(&icsk->icsk_pending, what);
244		sk_reset_timer(sk, &sk->tcp_retransmit_timer, when);
245	} else if (what == ICSK_TIME_DACK) {
246		smp_store_release(&icsk->icsk_ack.pending,
247				  icsk->icsk_ack.pending | ICSK_ACK_TIMER);
248		sk_reset_timer(sk, &icsk->icsk_delack_timer, when);
249	} else {
250		pr_debug("inet_csk BUG: unknown timer value\n");
251	}
252}
253
254static inline unsigned long
255inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
256		     unsigned long max_when)
257{
258        u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
259
260        return (unsigned long)min_t(u64, when, max_when);
261}
262
263struct sock *inet_csk_accept(struct sock *sk, struct proto_accept_arg *arg);
264
265int inet_csk_get_port(struct sock *sk, unsigned short snum);
266
267struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
268				     const struct request_sock *req);
269struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
270					    struct sock *newsk,
271					    const struct request_sock *req);
272
273struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
274				      struct request_sock *req,
275				      struct sock *child);
276bool inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req);
277struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
278					 struct request_sock *req,
279					 bool own_req);
280
281static inline void inet_csk_reqsk_queue_added(struct sock *sk)
282{
283	reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
284}
285
286static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
287{
288	return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
289}
290
291static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
292{
293	return inet_csk_reqsk_queue_len(sk) > READ_ONCE(sk->sk_max_ack_backlog);
294}
295
296bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
297void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
298
299void inet_csk_destroy_sock(struct sock *sk);
300void inet_csk_prepare_for_destroy_sock(struct sock *sk);
301void inet_csk_prepare_forced_close(struct sock *sk);
302
303/*
304 * LISTEN is a special case for poll..
305 */
306static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
307{
308	return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
309			(EPOLLIN | EPOLLRDNORM) : 0;
310}
311
312int inet_csk_listen_start(struct sock *sk);
313void inet_csk_listen_stop(struct sock *sk);
314
315/* update the fast reuse flag when adding a socket */
316void inet_csk_update_fastreuse(const struct sock *sk,
317			       struct inet_bind_bucket *tb,
318			       struct inet_bind2_bucket *tb2);
319
320struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
321
322static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
323{
324	inet_csk(sk)->icsk_ack.pingpong =
325		READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pingpong_thresh);
326}
327
328static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
329{
330	inet_csk(sk)->icsk_ack.pingpong = 0;
331}
332
333static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
334{
335	return inet_csk(sk)->icsk_ack.pingpong >=
336	       READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pingpong_thresh);
337}
338
339static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
340{
341	struct inet_connection_sock *icsk = inet_csk(sk);
342
343	if (icsk->icsk_ack.pingpong < U8_MAX)
344		icsk->icsk_ack.pingpong++;
345}
346
347static inline bool inet_csk_has_ulp(const struct sock *sk)
348{
349	return inet_test_bit(IS_ICSK, sk) && !!inet_csk(sk)->icsk_ulp_ops;
350}
351
352static inline void inet_init_csk_locks(struct sock *sk)
353{
354	struct inet_connection_sock *icsk = inet_csk(sk);
355
356	spin_lock_init(&icsk->icsk_accept_queue.rskq_lock);
357	spin_lock_init(&icsk->icsk_accept_queue.fastopenq.lock);
358}
359
360#endif /* _INET_CONNECTION_SOCK_H */