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_ipv6only		__tw_common.skc_ipv6only
47 #define tw_bound_dev_if		__tw_common.skc_bound_dev_if
48 #define tw_node			__tw_common.skc_nulls_node
49 #define tw_bind_node		__tw_common.skc_bind_node
50 #define tw_refcnt		__tw_common.skc_refcnt
51 #define tw_hash			__tw_common.skc_hash
52 #define tw_prot			__tw_common.skc_prot
53 #define tw_net			__tw_common.skc_net
54 #define tw_daddr        	__tw_common.skc_daddr
55 #define tw_v6_daddr		__tw_common.skc_v6_daddr
56 #define tw_rcv_saddr    	__tw_common.skc_rcv_saddr
57 #define tw_v6_rcv_saddr    	__tw_common.skc_v6_rcv_saddr
58 #define tw_dport		__tw_common.skc_dport
59 #define tw_num			__tw_common.skc_num
60 #define tw_cookie		__tw_common.skc_cookie
61 #define tw_dr			__tw_common.skc_tw_dr
62 
63 	int			tw_timeout;
64 	volatile unsigned char	tw_substate;
65 	unsigned char		tw_rcv_wscale;
66 
67 	/* Socket demultiplex comparisons on incoming packets. */
68 	/* these three are in inet_sock */
69 	__be16			tw_sport;
70 	/* And these are ours. */
71 	unsigned int		tw_kill		: 1,
72 				tw_transparent  : 1,
73 				tw_flowlabel	: 20,
74 				tw_pad		: 2,	/* 2 bits hole */
75 				tw_tos		: 8;
76 	struct timer_list	tw_timer;
77 	struct inet_bind_bucket	*tw_tb;
78 };
79 #define tw_tclass tw_tos
80 
81 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
82 {
83 	return (struct inet_timewait_sock *)sk;
84 }
85 
86 void inet_twsk_free(struct inet_timewait_sock *tw);
87 void inet_twsk_put(struct inet_timewait_sock *tw);
88 
89 void inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
90 			   struct inet_hashinfo *hashinfo);
91 
92 struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
93 					   struct inet_timewait_death_row *dr,
94 					   const int state);
95 
96 void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
97 			 struct inet_hashinfo *hashinfo);
98 
99 void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo,
100 			  bool rearm);
101 
102 static inline void inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo)
103 {
104 	__inet_twsk_schedule(tw, timeo, false);
105 }
106 
107 static inline void inet_twsk_reschedule(struct inet_timewait_sock *tw, int timeo)
108 {
109 	__inet_twsk_schedule(tw, timeo, true);
110 }
111 
112 void inet_twsk_deschedule_put(struct inet_timewait_sock *tw);
113 
114 void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family);
115 
116 static inline
117 struct net *twsk_net(const struct inet_timewait_sock *twsk)
118 {
119 	return read_pnet(&twsk->tw_net);
120 }
121 
122 static inline
123 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
124 {
125 	write_pnet(&twsk->tw_net, net);
126 }
127 #endif	/* _INET_TIMEWAIT_SOCK_ */
128