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 inet_bind2_bucket;
29  struct tcp_congestion_ops;
30  
31  /*
32   * Pointers to address related TCP functions
33   * (i.e. things that depend on the address family)
34   */
35  struct 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   */
82  struct 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  
150  #define inet_csk(ptr) container_of_const(ptr, struct inet_connection_sock, icsk_inet.sk)
151  
inet_csk_ca(const struct sock * sk)152  static inline void *inet_csk_ca(const struct sock *sk)
153  {
154  	return (void *)inet_csk(sk)->icsk_ca_priv;
155  }
156  
157  struct sock *inet_csk_clone_lock(const struct sock *sk,
158  				 const struct request_sock *req,
159  				 const gfp_t priority);
160  
161  enum 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  
170  void 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 *));
174  void inet_csk_clear_xmit_timers(struct sock *sk);
175  void inet_csk_clear_xmit_timers_sync(struct sock *sk);
176  
inet_csk_schedule_ack(struct sock * sk)177  static inline void inet_csk_schedule_ack(struct sock *sk)
178  {
179  	inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
180  }
181  
inet_csk_ack_scheduled(const struct sock * sk)182  static inline int inet_csk_ack_scheduled(const struct sock *sk)
183  {
184  	return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
185  }
186  
inet_csk_delack_init(struct sock * sk)187  static 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  
192  void inet_csk_delete_keepalive_timer(struct sock *sk);
193  void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
194  
inet_csk_clear_xmit_timer(struct sock * sk,const int what)195  static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
196  {
197  	struct inet_connection_sock *icsk = inet_csk(sk);
198  
199  	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
200  		icsk->icsk_pending = 0;
201  #ifdef INET_CSK_CLEAR_TIMERS
202  		sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
203  #endif
204  	} else if (what == ICSK_TIME_DACK) {
205  		icsk->icsk_ack.pending = 0;
206  		icsk->icsk_ack.retry = 0;
207  #ifdef INET_CSK_CLEAR_TIMERS
208  		sk_stop_timer(sk, &icsk->icsk_delack_timer);
209  #endif
210  	} else {
211  		pr_debug("inet_csk BUG: unknown timer value\n");
212  	}
213  }
214  
215  /*
216   *	Reset the retransmission timer
217   */
inet_csk_reset_xmit_timer(struct sock * sk,const int what,unsigned long when,const unsigned long max_when)218  static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
219  					     unsigned long when,
220  					     const unsigned long max_when)
221  {
222  	struct inet_connection_sock *icsk = inet_csk(sk);
223  
224  	if (when > max_when) {
225  		pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
226  			 sk, what, when, (void *)_THIS_IP_);
227  		when = max_when;
228  	}
229  
230  	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
231  	    what == ICSK_TIME_LOSS_PROBE || what == ICSK_TIME_REO_TIMEOUT) {
232  		icsk->icsk_pending = what;
233  		icsk->icsk_timeout = jiffies + when;
234  		sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
235  	} else if (what == ICSK_TIME_DACK) {
236  		icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
237  		icsk->icsk_ack.timeout = jiffies + when;
238  		sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
239  	} else {
240  		pr_debug("inet_csk BUG: unknown timer value\n");
241  	}
242  }
243  
244  static inline unsigned long
inet_csk_rto_backoff(const struct inet_connection_sock * icsk,unsigned long max_when)245  inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
246  		     unsigned long max_when)
247  {
248          u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
249  
250          return (unsigned long)min_t(u64, when, max_when);
251  }
252  
253  struct sock *inet_csk_accept(struct sock *sk, struct proto_accept_arg *arg);
254  
255  int inet_csk_get_port(struct sock *sk, unsigned short snum);
256  
257  struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
258  				     const struct request_sock *req);
259  struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
260  					    struct sock *newsk,
261  					    const struct request_sock *req);
262  
263  struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
264  				      struct request_sock *req,
265  				      struct sock *child);
266  bool inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
267  				   unsigned long timeout);
268  struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
269  					 struct request_sock *req,
270  					 bool own_req);
271  
inet_csk_reqsk_queue_added(struct sock * sk)272  static inline void inet_csk_reqsk_queue_added(struct sock *sk)
273  {
274  	reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
275  }
276  
inet_csk_reqsk_queue_len(const struct sock * sk)277  static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
278  {
279  	return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
280  }
281  
inet_csk_reqsk_queue_is_full(const struct sock * sk)282  static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
283  {
284  	return inet_csk_reqsk_queue_len(sk) >= READ_ONCE(sk->sk_max_ack_backlog);
285  }
286  
287  bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
288  void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
289  
290  static inline unsigned long
reqsk_timeout(struct request_sock * req,unsigned long max_timeout)291  reqsk_timeout(struct request_sock *req, unsigned long max_timeout)
292  {
293  	u64 timeout = (u64)req->timeout << req->num_timeout;
294  
295  	return (unsigned long)min_t(u64, timeout, max_timeout);
296  }
297  
inet_csk_prepare_for_destroy_sock(struct sock * sk)298  static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk)
299  {
300  	/* The below has to be done to allow calling inet_csk_destroy_sock */
301  	sock_set_flag(sk, SOCK_DEAD);
302  	this_cpu_inc(*sk->sk_prot->orphan_count);
303  }
304  
305  void inet_csk_destroy_sock(struct sock *sk);
306  void inet_csk_prepare_forced_close(struct sock *sk);
307  
308  /*
309   * LISTEN is a special case for poll..
310   */
inet_csk_listen_poll(const struct sock * sk)311  static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
312  {
313  	return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
314  			(EPOLLIN | EPOLLRDNORM) : 0;
315  }
316  
317  int inet_csk_listen_start(struct sock *sk);
318  void inet_csk_listen_stop(struct sock *sk);
319  
320  void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
321  
322  /* update the fast reuse flag when adding a socket */
323  void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
324  			       struct sock *sk);
325  
326  struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
327  
inet_csk_enter_pingpong_mode(struct sock * sk)328  static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
329  {
330  	inet_csk(sk)->icsk_ack.pingpong =
331  		READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pingpong_thresh);
332  }
333  
inet_csk_exit_pingpong_mode(struct sock * sk)334  static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
335  {
336  	inet_csk(sk)->icsk_ack.pingpong = 0;
337  }
338  
inet_csk_in_pingpong_mode(struct sock * sk)339  static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
340  {
341  	return inet_csk(sk)->icsk_ack.pingpong >=
342  	       READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pingpong_thresh);
343  }
344  
inet_csk_inc_pingpong_cnt(struct sock * sk)345  static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
346  {
347  	struct inet_connection_sock *icsk = inet_csk(sk);
348  
349  	if (icsk->icsk_ack.pingpong < U8_MAX)
350  		icsk->icsk_ack.pingpong++;
351  }
352  
inet_csk_has_ulp(const struct sock * sk)353  static inline bool inet_csk_has_ulp(const struct sock *sk)
354  {
355  	return inet_test_bit(IS_ICSK, sk) && !!inet_csk(sk)->icsk_ulp_ops;
356  }
357  
inet_init_csk_locks(struct sock * sk)358  static inline void inet_init_csk_locks(struct sock *sk)
359  {
360  	struct inet_connection_sock *icsk = inet_csk(sk);
361  
362  	spin_lock_init(&icsk->icsk_accept_queue.rskq_lock);
363  	spin_lock_init(&icsk->icsk_accept_queue.fastopenq.lock);
364  }
365  
366  #endif /* _INET_CONNECTION_SOCK_H */
367