1 /*
2  * NET		Generic infrastructure for INET connection oriented protocols.
3  *
4  *		Definitions for inet_connection_sock
5  *
6  * Authors:	Many people, see the TCP sources
7  *
8  * 		From code originally in TCP
9  *
10  *		This program is free software; you can redistribute it and/or
11  *		modify it under the terms of the GNU General Public License
12  *		as published by the Free Software Foundation; either version
13  *		2 of the License, or (at your option) any later version.
14  */
15 #ifndef _INET_CONNECTION_SOCK_H
16 #define _INET_CONNECTION_SOCK_H
17 
18 #include <linux/compiler.h>
19 #include <linux/string.h>
20 #include <linux/timer.h>
21 #include <linux/poll.h>
22 
23 #include <net/inet_sock.h>
24 #include <net/request_sock.h>
25 
26 #define INET_CSK_DEBUG 1
27 
28 /* Cancel timers, when they are not required. */
29 #undef INET_CSK_CLEAR_TIMERS
30 
31 struct inet_bind_bucket;
32 struct tcp_congestion_ops;
33 
34 /*
35  * Pointers to address related TCP functions
36  * (i.e. things that depend on the address family)
37  */
38 struct inet_connection_sock_af_ops {
39 	int	    (*queue_xmit)(struct sk_buff *skb, int ipfragok);
40 	void	    (*send_check)(struct sock *sk, int len,
41 				  struct sk_buff *skb);
42 	int	    (*rebuild_header)(struct sock *sk);
43 	int	    (*conn_request)(struct sock *sk, struct sk_buff *skb);
44 	struct sock *(*syn_recv_sock)(struct sock *sk, struct sk_buff *skb,
45 				      struct request_sock *req,
46 				      struct dst_entry *dst);
47 	int	    (*remember_stamp)(struct sock *sk);
48 	u16	    net_header_len;
49 	u16	    sockaddr_len;
50 	int	    (*setsockopt)(struct sock *sk, int level, int optname,
51 				  char __user *optval, int optlen);
52 	int	    (*getsockopt)(struct sock *sk, int level, int optname,
53 				  char __user *optval, int __user *optlen);
54 #ifdef CONFIG_COMPAT
55 	int	    (*compat_setsockopt)(struct sock *sk,
56 				int level, int optname,
57 				char __user *optval, int optlen);
58 	int	    (*compat_getsockopt)(struct sock *sk,
59 				int level, int optname,
60 				char __user *optval, int __user *optlen);
61 #endif
62 	void	    (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
63 	int	    (*bind_conflict)(const struct sock *sk,
64 				     const struct inet_bind_bucket *tb);
65 };
66 
67 /** inet_connection_sock - INET connection oriented sock
68  *
69  * @icsk_accept_queue:	   FIFO of established children
70  * @icsk_bind_hash:	   Bind node
71  * @icsk_timeout:	   Timeout
72  * @icsk_retransmit_timer: Resend (no ack)
73  * @icsk_rto:		   Retransmit timeout
74  * @icsk_pmtu_cookie	   Last pmtu seen by socket
75  * @icsk_ca_ops		   Pluggable congestion control hook
76  * @icsk_af_ops		   Operations which are AF_INET{4,6} specific
77  * @icsk_ca_state:	   Congestion control state
78  * @icsk_retransmits:	   Number of unrecovered [RTO] timeouts
79  * @icsk_pending:	   Scheduled timer event
80  * @icsk_backoff:	   Backoff
81  * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
82  * @icsk_probes_out:	   unanswered 0 window probes
83  * @icsk_ext_hdr_len:	   Network protocol overhead (IP/IPv6 options)
84  * @icsk_ack:		   Delayed ACK control data
85  * @icsk_mtup;		   MTU probing control data
86  */
87 struct inet_connection_sock {
88 	/* inet_sock has to be the first member! */
89 	struct inet_sock	  icsk_inet;
90 	struct request_sock_queue icsk_accept_queue;
91 	struct inet_bind_bucket	  *icsk_bind_hash;
92 	unsigned long		  icsk_timeout;
93  	struct timer_list	  icsk_retransmit_timer;
94  	struct timer_list	  icsk_delack_timer;
95 	__u32			  icsk_rto;
96 	__u32			  icsk_pmtu_cookie;
97 	const struct tcp_congestion_ops *icsk_ca_ops;
98 	const struct inet_connection_sock_af_ops *icsk_af_ops;
99 	unsigned int		  (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
100 	__u8			  icsk_ca_state;
101 	__u8			  icsk_retransmits;
102 	__u8			  icsk_pending;
103 	__u8			  icsk_backoff;
104 	__u8			  icsk_syn_retries;
105 	__u8			  icsk_probes_out;
106 	__u16			  icsk_ext_hdr_len;
107 	struct {
108 		__u8		  pending;	 /* ACK is pending			   */
109 		__u8		  quick;	 /* Scheduled number of quick acks	   */
110 		__u8		  pingpong;	 /* The session is interactive		   */
111 		__u8		  blocked;	 /* Delayed ACK was blocked by socket lock */
112 		__u32		  ato;		 /* Predicted tick of soft clock	   */
113 		unsigned long	  timeout;	 /* Currently scheduled timeout		   */
114 		__u32		  lrcvtime;	 /* timestamp of last received data packet */
115 		__u16		  last_seg_size; /* Size of last incoming segment	   */
116 		__u16		  rcv_mss;	 /* MSS used for delayed ACK decisions	   */
117 	} icsk_ack;
118 	struct {
119 		int		  enabled;
120 
121 		/* Range of MTUs to search */
122 		int		  search_high;
123 		int		  search_low;
124 
125 		/* Information on the current probe. */
126 		int		  probe_size;
127 	} icsk_mtup;
128 	u32			  icsk_ca_priv[16];
129 #define ICSK_CA_PRIV_SIZE	(16 * sizeof(u32))
130 };
131 
132 #define ICSK_TIME_RETRANS	1	/* Retransmit timer */
133 #define ICSK_TIME_DACK		2	/* Delayed ack timer */
134 #define ICSK_TIME_PROBE0	3	/* Zero window probe timer */
135 #define ICSK_TIME_KEEPOPEN	4	/* Keepalive timer */
136 
137 static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
138 {
139 	return (struct inet_connection_sock *)sk;
140 }
141 
142 static inline void *inet_csk_ca(const struct sock *sk)
143 {
144 	return (void *)inet_csk(sk)->icsk_ca_priv;
145 }
146 
147 extern struct sock *inet_csk_clone(struct sock *sk,
148 				   const struct request_sock *req,
149 				   const gfp_t priority);
150 
151 enum inet_csk_ack_state_t {
152 	ICSK_ACK_SCHED	= 1,
153 	ICSK_ACK_TIMER  = 2,
154 	ICSK_ACK_PUSHED = 4,
155 	ICSK_ACK_PUSHED2 = 8
156 };
157 
158 extern void inet_csk_init_xmit_timers(struct sock *sk,
159 				      void (*retransmit_handler)(unsigned long),
160 				      void (*delack_handler)(unsigned long),
161 				      void (*keepalive_handler)(unsigned long));
162 extern void inet_csk_clear_xmit_timers(struct sock *sk);
163 
164 static inline void inet_csk_schedule_ack(struct sock *sk)
165 {
166 	inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
167 }
168 
169 static inline int inet_csk_ack_scheduled(const struct sock *sk)
170 {
171 	return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
172 }
173 
174 static inline void inet_csk_delack_init(struct sock *sk)
175 {
176 	memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
177 }
178 
179 extern void inet_csk_delete_keepalive_timer(struct sock *sk);
180 extern void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
181 
182 #ifdef INET_CSK_DEBUG
183 extern const char inet_csk_timer_bug_msg[];
184 #endif
185 
186 static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
187 {
188 	struct inet_connection_sock *icsk = inet_csk(sk);
189 
190 	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
191 		icsk->icsk_pending = 0;
192 #ifdef INET_CSK_CLEAR_TIMERS
193 		sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
194 #endif
195 	} else if (what == ICSK_TIME_DACK) {
196 		icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
197 #ifdef INET_CSK_CLEAR_TIMERS
198 		sk_stop_timer(sk, &icsk->icsk_delack_timer);
199 #endif
200 	}
201 #ifdef INET_CSK_DEBUG
202 	else {
203 		pr_debug("%s", inet_csk_timer_bug_msg);
204 	}
205 #endif
206 }
207 
208 /*
209  *	Reset the retransmission timer
210  */
211 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
212 					     unsigned long when,
213 					     const unsigned long max_when)
214 {
215 	struct inet_connection_sock *icsk = inet_csk(sk);
216 
217 	if (when > max_when) {
218 #ifdef INET_CSK_DEBUG
219 		pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
220 			 sk, what, when, current_text_addr());
221 #endif
222 		when = max_when;
223 	}
224 
225 	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
226 		icsk->icsk_pending = what;
227 		icsk->icsk_timeout = jiffies + when;
228 		sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
229 	} else if (what == ICSK_TIME_DACK) {
230 		icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
231 		icsk->icsk_ack.timeout = jiffies + when;
232 		sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
233 	}
234 #ifdef INET_CSK_DEBUG
235 	else {
236 		pr_debug("%s", inet_csk_timer_bug_msg);
237 	}
238 #endif
239 }
240 
241 extern struct sock *inet_csk_accept(struct sock *sk, int flags, int *err);
242 
243 extern struct request_sock *inet_csk_search_req(const struct sock *sk,
244 						struct request_sock ***prevp,
245 						const __be16 rport,
246 						const __be32 raddr,
247 						const __be32 laddr);
248 extern int inet_csk_bind_conflict(const struct sock *sk,
249 				  const struct inet_bind_bucket *tb);
250 extern int inet_csk_get_port(struct sock *sk, unsigned short snum);
251 
252 extern struct dst_entry* inet_csk_route_req(struct sock *sk,
253 					    const struct request_sock *req);
254 
255 static inline void inet_csk_reqsk_queue_add(struct sock *sk,
256 					    struct request_sock *req,
257 					    struct sock *child)
258 {
259 	reqsk_queue_add(&inet_csk(sk)->icsk_accept_queue, req, sk, child);
260 }
261 
262 extern void inet_csk_reqsk_queue_hash_add(struct sock *sk,
263 					  struct request_sock *req,
264 					  unsigned long timeout);
265 
266 static inline void inet_csk_reqsk_queue_removed(struct sock *sk,
267 						struct request_sock *req)
268 {
269 	if (reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req) == 0)
270 		inet_csk_delete_keepalive_timer(sk);
271 }
272 
273 static inline void inet_csk_reqsk_queue_added(struct sock *sk,
274 					      const unsigned long timeout)
275 {
276 	if (reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue) == 0)
277 		inet_csk_reset_keepalive_timer(sk, timeout);
278 }
279 
280 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
281 {
282 	return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
283 }
284 
285 static inline int inet_csk_reqsk_queue_young(const struct sock *sk)
286 {
287 	return reqsk_queue_len_young(&inet_csk(sk)->icsk_accept_queue);
288 }
289 
290 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
291 {
292 	return reqsk_queue_is_full(&inet_csk(sk)->icsk_accept_queue);
293 }
294 
295 static inline void inet_csk_reqsk_queue_unlink(struct sock *sk,
296 					       struct request_sock *req,
297 					       struct request_sock **prev)
298 {
299 	reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req, prev);
300 }
301 
302 static inline void inet_csk_reqsk_queue_drop(struct sock *sk,
303 					     struct request_sock *req,
304 					     struct request_sock **prev)
305 {
306 	inet_csk_reqsk_queue_unlink(sk, req, prev);
307 	inet_csk_reqsk_queue_removed(sk, req);
308 	reqsk_free(req);
309 }
310 
311 extern void inet_csk_reqsk_queue_prune(struct sock *parent,
312 				       const unsigned long interval,
313 				       const unsigned long timeout,
314 				       const unsigned long max_rto);
315 
316 extern void inet_csk_destroy_sock(struct sock *sk);
317 
318 /*
319  * LISTEN is a special case for poll..
320  */
321 static inline unsigned int inet_csk_listen_poll(const struct sock *sk)
322 {
323 	return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
324 			(POLLIN | POLLRDNORM) : 0;
325 }
326 
327 extern int  inet_csk_listen_start(struct sock *sk, const int nr_table_entries);
328 extern void inet_csk_listen_stop(struct sock *sk);
329 
330 extern void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
331 
332 extern int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
333 				      char __user *optval, int __user *optlen);
334 extern int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
335 				      char __user *optval, int optlen);
336 #endif /* _INET_CONNECTION_SOCK_H */
337