1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		Definitions for a generic INET TIMEWAIT sock
7  *
8  *		From code originally in net/tcp.h
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_TIMEWAIT_SOCK_
16 #define _INET_TIMEWAIT_SOCK_
17 
18 #include <linux/list.h>
19 #include <linux/timer.h>
20 #include <linux/types.h>
21 #include <linux/workqueue.h>
22 
23 #include <net/inet_sock.h>
24 #include <net/sock.h>
25 #include <net/tcp_states.h>
26 #include <net/timewait_sock.h>
27 
28 #include <linux/atomic.h>
29 
30 struct inet_bind_bucket;
31 
32 /*
33  * This is a TIME_WAIT sock. It works around the memory consumption
34  * problems of sockets in such a state on heavily loaded servers, but
35  * without violating the protocol specification.
36  */
37 struct inet_timewait_sock {
38 	/*
39 	 * Now struct sock also uses sock_common, so please just
40 	 * don't add nothing before this first member (__tw_common) --acme
41 	 */
42 	struct sock_common	__tw_common;
43 #define tw_family		__tw_common.skc_family
44 #define tw_state		__tw_common.skc_state
45 #define tw_reuse		__tw_common.skc_reuse
46 #define tw_reuseport		__tw_common.skc_reuseport
47 #define tw_ipv6only		__tw_common.skc_ipv6only
48 #define tw_bound_dev_if		__tw_common.skc_bound_dev_if
49 #define tw_node			__tw_common.skc_nulls_node
50 #define tw_bind_node		__tw_common.skc_bind_node
51 #define tw_refcnt		__tw_common.skc_refcnt
52 #define tw_hash			__tw_common.skc_hash
53 #define tw_prot			__tw_common.skc_prot
54 #define tw_net			__tw_common.skc_net
55 #define tw_daddr        	__tw_common.skc_daddr
56 #define tw_v6_daddr		__tw_common.skc_v6_daddr
57 #define tw_rcv_saddr    	__tw_common.skc_rcv_saddr
58 #define tw_v6_rcv_saddr    	__tw_common.skc_v6_rcv_saddr
59 #define tw_dport		__tw_common.skc_dport
60 #define tw_num			__tw_common.skc_num
61 #define tw_cookie		__tw_common.skc_cookie
62 #define tw_dr			__tw_common.skc_tw_dr
63 
64 	int			tw_timeout;
65 	volatile unsigned char	tw_substate;
66 	unsigned char		tw_rcv_wscale;
67 
68 	/* Socket demultiplex comparisons on incoming packets. */
69 	/* these three are in inet_sock */
70 	__be16			tw_sport;
71 	/* And these are ours. */
72 	unsigned int		tw_kill		: 1,
73 				tw_transparent  : 1,
74 				tw_flowlabel	: 20,
75 				tw_pad		: 2,	/* 2 bits hole */
76 				tw_tos		: 8;
77 	struct timer_list	tw_timer;
78 	struct inet_bind_bucket	*tw_tb;
79 };
80 #define tw_tclass tw_tos
81 
82 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
83 {
84 	return (struct inet_timewait_sock *)sk;
85 }
86 
87 void inet_twsk_free(struct inet_timewait_sock *tw);
88 void inet_twsk_put(struct inet_timewait_sock *tw);
89 
90 void inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
91 			   struct inet_hashinfo *hashinfo);
92 
93 struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
94 					   struct inet_timewait_death_row *dr,
95 					   const int state);
96 
97 void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
98 			 struct inet_hashinfo *hashinfo);
99 
100 void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo,
101 			  bool rearm);
102 
103 static inline void inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo)
104 {
105 	__inet_twsk_schedule(tw, timeo, false);
106 }
107 
108 static inline void inet_twsk_reschedule(struct inet_timewait_sock *tw, int timeo)
109 {
110 	__inet_twsk_schedule(tw, timeo, true);
111 }
112 
113 void inet_twsk_deschedule_put(struct inet_timewait_sock *tw);
114 
115 void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family);
116 
117 static inline
118 struct net *twsk_net(const struct inet_timewait_sock *twsk)
119 {
120 	return read_pnet(&twsk->tw_net);
121 }
122 
123 static inline
124 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
125 {
126 	write_pnet(&twsk->tw_net, net);
127 }
128 #endif	/* _INET_TIMEWAIT_SOCK_ */
129