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 
19 #include <linux/kmemcheck.h>
20 #include <linux/list.h>
21 #include <linux/timer.h>
22 #include <linux/types.h>
23 #include <linux/workqueue.h>
24 
25 #include <net/inet_sock.h>
26 #include <net/sock.h>
27 #include <net/tcp_states.h>
28 #include <net/timewait_sock.h>
29 
30 #include <linux/atomic.h>
31 
32 struct inet_hashinfo;
33 
34 struct inet_timewait_death_row {
35 	atomic_t		tw_count;
36 
37 	struct inet_hashinfo 	*hashinfo ____cacheline_aligned_in_smp;
38 	int			sysctl_tw_recycle;
39 	int			sysctl_max_tw_buckets;
40 };
41 
42 struct inet_bind_bucket;
43 
44 /*
45  * This is a TIME_WAIT sock. It works around the memory consumption
46  * problems of sockets in such a state on heavily loaded servers, but
47  * without violating the protocol specification.
48  */
49 struct inet_timewait_sock {
50 	/*
51 	 * Now struct sock also uses sock_common, so please just
52 	 * don't add nothing before this first member (__tw_common) --acme
53 	 */
54 	struct sock_common	__tw_common;
55 #define tw_family		__tw_common.skc_family
56 #define tw_state		__tw_common.skc_state
57 #define tw_reuse		__tw_common.skc_reuse
58 #define tw_ipv6only		__tw_common.skc_ipv6only
59 #define tw_bound_dev_if		__tw_common.skc_bound_dev_if
60 #define tw_node			__tw_common.skc_nulls_node
61 #define tw_bind_node		__tw_common.skc_bind_node
62 #define tw_refcnt		__tw_common.skc_refcnt
63 #define tw_hash			__tw_common.skc_hash
64 #define tw_prot			__tw_common.skc_prot
65 #define tw_net			__tw_common.skc_net
66 #define tw_daddr        	__tw_common.skc_daddr
67 #define tw_v6_daddr		__tw_common.skc_v6_daddr
68 #define tw_rcv_saddr    	__tw_common.skc_rcv_saddr
69 #define tw_v6_rcv_saddr    	__tw_common.skc_v6_rcv_saddr
70 #define tw_dport		__tw_common.skc_dport
71 #define tw_num			__tw_common.skc_num
72 #define tw_cookie		__tw_common.skc_cookie
73 
74 	int			tw_timeout;
75 	volatile unsigned char	tw_substate;
76 	unsigned char		tw_rcv_wscale;
77 
78 	/* Socket demultiplex comparisons on incoming packets. */
79 	/* these three are in inet_sock */
80 	__be16			tw_sport;
81 	kmemcheck_bitfield_begin(flags);
82 	/* And these are ours. */
83 	unsigned int		tw_kill		: 1,
84 				tw_transparent  : 1,
85 				tw_flowlabel	: 20,
86 				tw_pad		: 2,	/* 2 bits hole */
87 				tw_tos		: 8;
88 	kmemcheck_bitfield_end(flags);
89 	struct timer_list	tw_timer;
90 	struct inet_bind_bucket	*tw_tb;
91 	struct inet_timewait_death_row *tw_dr;
92 };
93 #define tw_tclass tw_tos
94 
95 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
96 {
97 	return (struct inet_timewait_sock *)sk;
98 }
99 
100 void inet_twsk_free(struct inet_timewait_sock *tw);
101 void inet_twsk_put(struct inet_timewait_sock *tw);
102 
103 void inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
104 			   struct inet_hashinfo *hashinfo);
105 
106 struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
107 					   struct inet_timewait_death_row *dr,
108 					   const int state);
109 
110 void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
111 			   struct inet_hashinfo *hashinfo);
112 
113 void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo,
114 			  bool rearm);
115 
116 static inline void inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo)
117 {
118 	__inet_twsk_schedule(tw, timeo, false);
119 }
120 
121 static inline void inet_twsk_reschedule(struct inet_timewait_sock *tw, int timeo)
122 {
123 	__inet_twsk_schedule(tw, timeo, true);
124 }
125 
126 void inet_twsk_deschedule_put(struct inet_timewait_sock *tw);
127 
128 void inet_twsk_purge(struct inet_hashinfo *hashinfo,
129 		     struct inet_timewait_death_row *twdr, int family);
130 
131 static inline
132 struct net *twsk_net(const struct inet_timewait_sock *twsk)
133 {
134 	return read_pnet(&twsk->tw_net);
135 }
136 
137 static inline
138 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
139 {
140 	write_pnet(&twsk->tw_net, net);
141 }
142 #endif	/* _INET_TIMEWAIT_SOCK_ */
143