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 #include <linux/kernel.h>
23 
24 #include <net/inet_sock.h>
25 #include <net/request_sock.h>
26 
27 /* Cancel timers, when they are not required. */
28 #undef INET_CSK_CLEAR_TIMERS
29 
30 struct inet_bind_bucket;
31 struct tcp_congestion_ops;
32 
33 /*
34  * Pointers to address related TCP functions
35  * (i.e. things that depend on the address family)
36  */
37 struct inet_connection_sock_af_ops {
38 	int	    (*queue_xmit)(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
39 	void	    (*send_check)(struct sock *sk, struct sk_buff *skb);
40 	int	    (*rebuild_header)(struct sock *sk);
41 	void	    (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);
42 	int	    (*conn_request)(struct sock *sk, struct sk_buff *skb);
43 	struct sock *(*syn_recv_sock)(const struct sock *sk, struct sk_buff *skb,
44 				      struct request_sock *req,
45 				      struct dst_entry *dst,
46 				      struct request_sock *req_unhash,
47 				      bool *own_req);
48 	u16	    net_header_len;
49 	u16	    net_frag_header_len;
50 	u16	    sockaddr_len;
51 	int	    (*setsockopt)(struct sock *sk, int level, int optname,
52 				  char __user *optval, unsigned int optlen);
53 	int	    (*getsockopt)(struct sock *sk, int level, int optname,
54 				  char __user *optval, int __user *optlen);
55 #ifdef CONFIG_COMPAT
56 	int	    (*compat_setsockopt)(struct sock *sk,
57 				int level, int optname,
58 				char __user *optval, unsigned int optlen);
59 	int	    (*compat_getsockopt)(struct sock *sk,
60 				int level, int optname,
61 				char __user *optval, int __user *optlen);
62 #endif
63 	void	    (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
64 	void	    (*mtu_reduced)(struct sock *sk);
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_ulp_ops	   Pluggable ULP control hook
78  * @icsk_ulp_data	   ULP private data
79  * @icsk_clean_acked	   Clean acked data hook
80  * @icsk_listen_portaddr_node	hash to the portaddr listener hashtable
81  * @icsk_ca_state:	   Congestion control state
82  * @icsk_retransmits:	   Number of unrecovered [RTO] timeouts
83  * @icsk_pending:	   Scheduled timer event
84  * @icsk_backoff:	   Backoff
85  * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
86  * @icsk_probes_out:	   unanswered 0 window probes
87  * @icsk_ext_hdr_len:	   Network protocol overhead (IP/IPv6 options)
88  * @icsk_ack:		   Delayed ACK control data
89  * @icsk_mtup;		   MTU probing control data
90  */
91 struct inet_connection_sock {
92 	/* inet_sock has to be the first member! */
93 	struct inet_sock	  icsk_inet;
94 	struct request_sock_queue icsk_accept_queue;
95 	struct inet_bind_bucket	  *icsk_bind_hash;
96 	unsigned long		  icsk_timeout;
97  	struct timer_list	  icsk_retransmit_timer;
98  	struct timer_list	  icsk_delack_timer;
99 	__u32			  icsk_rto;
100 	__u32			  icsk_pmtu_cookie;
101 	const struct tcp_congestion_ops *icsk_ca_ops;
102 	const struct inet_connection_sock_af_ops *icsk_af_ops;
103 	const struct tcp_ulp_ops  *icsk_ulp_ops;
104 	void			  *icsk_ulp_data;
105 	void (*icsk_clean_acked)(struct sock *sk, u32 acked_seq);
106 	struct hlist_node         icsk_listen_portaddr_node;
107 	unsigned int		  (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
108 	__u8			  icsk_ca_state:6,
109 				  icsk_ca_setsockopt:1,
110 				  icsk_ca_dst_locked:1;
111 	__u8			  icsk_retransmits;
112 	__u8			  icsk_pending;
113 	__u8			  icsk_backoff;
114 	__u8			  icsk_syn_retries;
115 	__u8			  icsk_probes_out;
116 	__u16			  icsk_ext_hdr_len;
117 	struct {
118 		__u8		  pending;	 /* ACK is pending			   */
119 		__u8		  quick;	 /* Scheduled number of quick acks	   */
120 		__u8		  pingpong;	 /* The session is interactive		   */
121 		__u8		  blocked;	 /* Delayed ACK was blocked by socket lock */
122 		__u32		  ato;		 /* Predicted tick of soft clock	   */
123 		unsigned long	  timeout;	 /* Currently scheduled timeout		   */
124 		__u32		  lrcvtime;	 /* timestamp of last received data packet */
125 		__u16		  last_seg_size; /* Size of last incoming segment	   */
126 		__u16		  rcv_mss;	 /* MSS used for delayed ACK decisions	   */
127 	} icsk_ack;
128 	struct {
129 		int		  enabled;
130 
131 		/* Range of MTUs to search */
132 		int		  search_high;
133 		int		  search_low;
134 
135 		/* Information on the current probe. */
136 		int		  probe_size;
137 
138 		u32		  probe_timestamp;
139 	} icsk_mtup;
140 	u32			  icsk_user_timeout;
141 
142 	u64			  icsk_ca_priv[104 / sizeof(u64)];
143 #define ICSK_CA_PRIV_SIZE      (13 * sizeof(u64))
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_EARLY_RETRANS 4	/* Early retransmit timer */
150 #define ICSK_TIME_LOSS_PROBE	5	/* Tail loss probe timer */
151 #define ICSK_TIME_REO_TIMEOUT	6	/* Reordering timer */
152 
inet_csk(const struct sock * sk)153 static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
154 {
155 	return (struct inet_connection_sock *)sk;
156 }
157 
inet_csk_ca(const struct sock * sk)158 static inline void *inet_csk_ca(const struct sock *sk)
159 {
160 	return (void *)inet_csk(sk)->icsk_ca_priv;
161 }
162 
163 struct sock *inet_csk_clone_lock(const struct sock *sk,
164 				 const struct request_sock *req,
165 				 const gfp_t priority);
166 
167 enum inet_csk_ack_state_t {
168 	ICSK_ACK_SCHED	= 1,
169 	ICSK_ACK_TIMER  = 2,
170 	ICSK_ACK_PUSHED = 4,
171 	ICSK_ACK_PUSHED2 = 8,
172 	ICSK_ACK_NOW = 16	/* Send the next ACK immediately (once) */
173 };
174 
175 void inet_csk_init_xmit_timers(struct sock *sk,
176 			       void (*retransmit_handler)(struct timer_list *),
177 			       void (*delack_handler)(struct timer_list *),
178 			       void (*keepalive_handler)(struct timer_list *));
179 void inet_csk_clear_xmit_timers(struct sock *sk);
180 
inet_csk_schedule_ack(struct sock * sk)181 static inline void inet_csk_schedule_ack(struct sock *sk)
182 {
183 	inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_SCHED;
184 }
185 
inet_csk_ack_scheduled(const struct sock * sk)186 static inline int inet_csk_ack_scheduled(const struct sock *sk)
187 {
188 	return inet_csk(sk)->icsk_ack.pending & ICSK_ACK_SCHED;
189 }
190 
inet_csk_delack_init(struct sock * sk)191 static inline void inet_csk_delack_init(struct sock *sk)
192 {
193 	memset(&inet_csk(sk)->icsk_ack, 0, sizeof(inet_csk(sk)->icsk_ack));
194 }
195 
196 void inet_csk_delete_keepalive_timer(struct sock *sk);
197 void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long timeout);
198 
inet_csk_clear_xmit_timer(struct sock * sk,const int what)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 	} else {
214 		pr_debug("inet_csk BUG: unknown timer value\n");
215 	}
216 }
217 
218 /*
219  *	Reset the retransmission timer
220  */
inet_csk_reset_xmit_timer(struct sock * sk,const int what,unsigned long when,const unsigned long max_when)221 static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what,
222 					     unsigned long when,
223 					     const unsigned long max_when)
224 {
225 	struct inet_connection_sock *icsk = inet_csk(sk);
226 
227 	if (when > max_when) {
228 		pr_debug("reset_xmit_timer: sk=%p %d when=0x%lx, caller=%p\n",
229 			 sk, what, when, (void *)_THIS_IP_);
230 		when = max_when;
231 	}
232 
233 	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||
234 	    what == ICSK_TIME_EARLY_RETRANS || what == ICSK_TIME_LOSS_PROBE ||
235 	    what == ICSK_TIME_REO_TIMEOUT) {
236 		icsk->icsk_pending = what;
237 		icsk->icsk_timeout = jiffies + when;
238 		sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
239 	} else if (what == ICSK_TIME_DACK) {
240 		icsk->icsk_ack.pending |= ICSK_ACK_TIMER;
241 		icsk->icsk_ack.timeout = jiffies + when;
242 		sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
243 	} else {
244 		pr_debug("inet_csk BUG: unknown timer value\n");
245 	}
246 }
247 
248 static inline unsigned long
inet_csk_rto_backoff(const struct inet_connection_sock * icsk,unsigned long max_when)249 inet_csk_rto_backoff(const struct inet_connection_sock *icsk,
250 		     unsigned long max_when)
251 {
252         u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff;
253 
254         return (unsigned long)min_t(u64, when, max_when);
255 }
256 
257 struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern);
258 
259 int inet_csk_get_port(struct sock *sk, unsigned short snum);
260 
261 struct dst_entry *inet_csk_route_req(const struct sock *sk, struct flowi4 *fl4,
262 				     const struct request_sock *req);
263 struct dst_entry *inet_csk_route_child_sock(const struct sock *sk,
264 					    struct sock *newsk,
265 					    const struct request_sock *req);
266 
267 struct sock *inet_csk_reqsk_queue_add(struct sock *sk,
268 				      struct request_sock *req,
269 				      struct sock *child);
270 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
271 				   unsigned long timeout);
272 struct sock *inet_csk_complete_hashdance(struct sock *sk, struct sock *child,
273 					 struct request_sock *req,
274 					 bool own_req);
275 
inet_csk_reqsk_queue_added(struct sock * sk)276 static inline void inet_csk_reqsk_queue_added(struct sock *sk)
277 {
278 	reqsk_queue_added(&inet_csk(sk)->icsk_accept_queue);
279 }
280 
inet_csk_reqsk_queue_len(const struct sock * sk)281 static inline int inet_csk_reqsk_queue_len(const struct sock *sk)
282 {
283 	return reqsk_queue_len(&inet_csk(sk)->icsk_accept_queue);
284 }
285 
inet_csk_reqsk_queue_is_full(const struct sock * sk)286 static inline int inet_csk_reqsk_queue_is_full(const struct sock *sk)
287 {
288 	return inet_csk_reqsk_queue_len(sk) >= sk->sk_max_ack_backlog;
289 }
290 
291 bool inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req);
292 void inet_csk_reqsk_queue_drop_and_put(struct sock *sk, struct request_sock *req);
293 
294 void inet_csk_destroy_sock(struct sock *sk);
295 void inet_csk_prepare_forced_close(struct sock *sk);
296 
297 /*
298  * LISTEN is a special case for poll..
299  */
inet_csk_listen_poll(const struct sock * sk)300 static inline __poll_t inet_csk_listen_poll(const struct sock *sk)
301 {
302 	return !reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue) ?
303 			(EPOLLIN | EPOLLRDNORM) : 0;
304 }
305 
306 int inet_csk_listen_start(struct sock *sk, int backlog);
307 void inet_csk_listen_stop(struct sock *sk);
308 
309 void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
310 
311 int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
312 			       char __user *optval, int __user *optlen);
313 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
314 			       char __user *optval, unsigned int optlen);
315 
316 /* update the fast reuse flag when adding a socket */
317 void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
318 			       struct sock *sk);
319 
320 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
321 #endif /* _INET_CONNECTION_SOCK_H */
322