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 sock *sk, struct sk_buff *skb, struct flowi *fl);
40 	void	    (*send_check)(struct sock *sk, struct sk_buff *skb);
41 	int	    (*rebuild_header)(struct sock *sk);
42 	void	    (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
43 	int	    (*conn_request)(struct sock *sk, struct sk_buff *skb);
44 	struct sock *(*syn_recv_sock)(const struct sock *sk, struct sk_buff *skb,
45 				      struct request_sock *req,
46 				      struct dst_entry *dst,
47 				      struct request_sock *req_unhash,
48 				      bool *own_req);
49 	u16	    net_header_len;
50 	u16	    net_frag_header_len;
51 	u16	    sockaddr_len;
52 	int	    (*setsockopt)(struct sock *sk, int level, int optname,
53 				  char __user *optval, unsigned int optlen);
54 	int	    (*getsockopt)(struct sock *sk, int level, int optname,
55 				  char __user *optval, int __user *optlen);
56 #ifdef CONFIG_COMPAT
57 	int	    (*compat_setsockopt)(struct sock *sk,
58 				int level, int optname,
59 				char __user *optval, unsigned int optlen);
60 	int	    (*compat_getsockopt)(struct sock *sk,
61 				int level, int optname,
62 				char __user *optval, int __user *optlen);
63 #endif
64 	void	    (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
65 	void	    (*mtu_reduced)(struct sock *sk);
66 };
67 
68 /** inet_connection_sock - INET connection oriented sock
69  *
70  * @icsk_accept_queue:	   FIFO of established children
71  * @icsk_bind_hash:	   Bind node
72  * @icsk_timeout:	   Timeout
73  * @icsk_retransmit_timer: Resend (no ack)
74  * @icsk_rto:		   Retransmit timeout
75  * @icsk_pmtu_cookie	   Last pmtu seen by socket
76  * @icsk_ca_ops		   Pluggable congestion control hook
77  * @icsk_af_ops		   Operations which are AF_INET{4,6} specific
78  * @icsk_ulp_ops	   Pluggable ULP control hook
79  * @icsk_ulp_data	   ULP private data
80  * @icsk_ca_state:	   Congestion control state
81  * @icsk_retransmits:	   Number of unrecovered [RTO] timeouts
82  * @icsk_pending:	   Scheduled timer event
83  * @icsk_backoff:	   Backoff
84  * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
85  * @icsk_probes_out:	   unanswered 0 window probes
86  * @icsk_ext_hdr_len:	   Network protocol overhead (IP/IPv6 options)
87  * @icsk_ack:		   Delayed ACK control data
88  * @icsk_mtup;		   MTU probing control data
89  */
90 struct inet_connection_sock {
91 	/* inet_sock has to be the first member! */
92 	struct inet_sock	  icsk_inet;
93 	struct request_sock_queue icsk_accept_queue;
94 	struct inet_bind_bucket	  *icsk_bind_hash;
95 	unsigned long		  icsk_timeout;
96  	struct timer_list	  icsk_retransmit_timer;
97  	struct timer_list	  icsk_delack_timer;
98 	__u32			  icsk_rto;
99 	__u32			  icsk_pmtu_cookie;
100 	const struct tcp_congestion_ops *icsk_ca_ops;
101 	const struct inet_connection_sock_af_ops *icsk_af_ops;
102 	const struct tcp_ulp_ops  *icsk_ulp_ops;
103 	void			  *icsk_ulp_data;
104 	unsigned int		  (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
105 	__u8			  icsk_ca_state:6,
106 				  icsk_ca_setsockopt:1,
107 				  icsk_ca_dst_locked:1;
108 	__u8			  icsk_retransmits;
109 	__u8			  icsk_pending;
110 	__u8			  icsk_backoff;
111 	__u8			  icsk_syn_retries;
112 	__u8			  icsk_probes_out;
113 	__u16			  icsk_ext_hdr_len;
114 	struct {
115 		__u8		  pending;	 /* ACK is pending			   */
116 		__u8		  quick;	 /* Scheduled number of quick acks	   */
117 		__u8		  pingpong;	 /* The session is interactive		   */
118 		__u8		  blocked;	 /* Delayed ACK was blocked by socket lock */
119 		__u32		  ato;		 /* Predicted tick of soft clock	   */
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 		int		  enabled;
127 
128 		/* Range of MTUs to search */
129 		int		  search_high;
130 		int		  search_low;
131 
132 		/* Information on the current probe. */
133 		int		  probe_size;
134 
135 		u32		  probe_timestamp;
136 	} icsk_mtup;
137 	u32			  icsk_user_timeout;
138 
139 	u64			  icsk_ca_priv[88 / sizeof(u64)];
140 #define ICSK_CA_PRIV_SIZE      (11 * sizeof(u64))
141 };
142 
143 #define ICSK_TIME_RETRANS	1	/* Retransmit timer */
144 #define ICSK_TIME_DACK		2	/* Delayed ack timer */
145 #define ICSK_TIME_PROBE0	3	/* Zero window probe timer */
146 #define ICSK_TIME_EARLY_RETRANS 4	/* Early retransmit timer */
147 #define ICSK_TIME_LOSS_PROBE	5	/* Tail loss probe timer */
148 #define ICSK_TIME_REO_TIMEOUT	6	/* Reordering timer */
149 
150 static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
151 {
152 	return (struct inet_connection_sock *)sk;
153 }
154 
155 static inline void *inet_csk_ca(const struct sock *sk)
156 {
157 	return (void *)inet_csk(sk)->icsk_ca_priv;
158 }
159 
160 struct sock *inet_csk_clone_lock(const struct sock *sk,
161 				 const struct request_sock *req,
162 				 const gfp_t priority);
163 
164 enum inet_csk_ack_state_t {
165 	ICSK_ACK_SCHED	= 1,
166 	ICSK_ACK_TIMER  = 2,
167 	ICSK_ACK_PUSHED = 4,
168 	ICSK_ACK_PUSHED2 = 8
169 };
170 
171 void inet_csk_init_xmit_timers(struct sock *sk,
172 			       void (*retransmit_handler)(unsigned long),
173 			       void (*delack_handler)(unsigned long),
174 			       void (*keepalive_handler)(unsigned long));
175 void inet_csk_clear_xmit_timers(struct sock *sk);
176 
177 static inline void inet_csk_schedule_ack(struct sock *sk)
178 {
179 	inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
180 }
181 
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 
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 
195 #ifdef INET_CSK_DEBUG
196 extern const char inet_csk_timer_bug_msg[];
197 #endif
198 
199 static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)
200 {
201 	struct inet_connection_sock *icsk = inet_csk(sk);
202 
203 	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0) {
204 		icsk->icsk_pending = 0;
205 #ifdef INET_CSK_CLEAR_TIMERS
206 		sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
207 #endif
208 	} else if (what == ICSK_TIME_DACK) {
209 		icsk->icsk_ack.blocked = icsk->icsk_ack.pending = 0;
210 #ifdef INET_CSK_CLEAR_TIMERS
211 		sk_stop_timer(sk, &icsk->icsk_delack_timer);
212 #endif
213 	}
214 #ifdef INET_CSK_DEBUG
215 	else {
216 		pr_debug("%s", inet_csk_timer_bug_msg);
217 	}
218 #endif
219 }
220 
221 /*
222  *	Reset the retransmission timer
223  */
224 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
225 					     unsigned long when,
226 					     const unsigned long max_when)
227 {
228 	struct inet_connection_sock *icsk = inet_csk(sk);
229 
230 	if (when > max_when) {
231 #ifdef INET_CSK_DEBUG
232 		pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
233 			 sk, what, when, current_text_addr());
234 #endif
235 		when = max_when;
236 	}
237 
238 	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
239 	    what == ICSK_TIME_EARLY_RETRANS || what == ICSK_TIME_LOSS_PROBE ||
240 	    what == ICSK_TIME_REO_TIMEOUT) {
241 		icsk->icsk_pending = what;
242 		icsk->icsk_timeout = jiffies + when;
243 		sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
244 	} else if (what == ICSK_TIME_DACK) {
245 		icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
246 		icsk->icsk_ack.timeout = jiffies + when;
247 		sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
248 	}
249 #ifdef INET_CSK_DEBUG
250 	else {
251 		pr_debug("%s", inet_csk_timer_bug_msg);
252 	}
253 #endif
254 }
255 
256 static inline unsigned long
257 inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
258 		     unsigned long max_when)
259 {
260         u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
261 
262         return (unsigned long)min_t(u64, when, max_when);
263 }
264 
265 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern);
266 
267 int inet_csk_get_port(struct sock *sk, unsigned short snum);
268 
269 struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
270 				     const struct request_sock *req);
271 struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
272 					    struct sock *newsk,
273 					    const struct request_sock *req);
274 
275 struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
276 				      struct request_sock *req,
277 				      struct sock *child);
278 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
279 				   unsigned long timeout);
280 struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
281 					 struct request_sock *req,
282 					 bool own_req);
283 
284 static inline void inet_csk_reqsk_queue_added(struct sock *sk)
285 {
286 	reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
287 }
288 
289 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
290 {
291 	return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
292 }
293 
294 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
295 {
296 	return inet_csk_reqsk_queue_len(sk) >= sk->sk_max_ack_backlog;
297 }
298 
299 void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
300 void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
301 
302 void inet_csk_destroy_sock(struct sock *sk);
303 void inet_csk_prepare_forced_close(struct sock *sk);
304 
305 /*
306  * LISTEN is a special case for poll..
307  */
308 static inline unsigned int inet_csk_listen_poll(const struct sock *sk)
309 {
310 	return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
311 			(POLLIN | POLLRDNORM) : 0;
312 }
313 
314 int inet_csk_listen_start(struct sock *sk, int backlog);
315 void inet_csk_listen_stop(struct sock *sk);
316 
317 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
318 
319 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
320 			       char __user *optval, int __user *optlen);
321 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
322 			       char __user *optval, unsigned int optlen);
323 
324 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
325 #endif /* _INET_CONNECTION_SOCK_H */
326