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/list.h>
20 #include <linux/module.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 <asm/atomic.h>
31
32 struct inet_hashinfo;
33
34 #define INET_TWDR_RECYCLE_SLOTS_LOG 5
35 #define INET_TWDR_RECYCLE_SLOTS (1 << INET_TWDR_RECYCLE_SLOTS_LOG)
36
37 /*
38 * If time > 4sec, it is "slow" path, no recycling is required,
39 * so that we select tick to get range about 4 seconds.
40 */
41 #if HZ <= 16 || HZ > 4096
42 # error Unsupported: HZ <= 16 or HZ > 4096
43 #elif HZ <= 32
44 # define INET_TWDR_RECYCLE_TICK (5 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
45 #elif HZ <= 64
46 # define INET_TWDR_RECYCLE_TICK (6 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
47 #elif HZ <= 128
48 # define INET_TWDR_RECYCLE_TICK (7 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
49 #elif HZ <= 256
50 # define INET_TWDR_RECYCLE_TICK (8 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
51 #elif HZ <= 512
52 # define INET_TWDR_RECYCLE_TICK (9 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
53 #elif HZ <= 1024
54 # define INET_TWDR_RECYCLE_TICK (10 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
55 #elif HZ <= 2048
56 # define INET_TWDR_RECYCLE_TICK (11 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
57 #else
58 # define INET_TWDR_RECYCLE_TICK (12 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
59 #endif
60
61 /* TIME_WAIT reaping mechanism. */
62 #define INET_TWDR_TWKILL_SLOTS 8 /* Please keep this a power of 2. */
63
64 #define INET_TWDR_TWKILL_QUOTA 100
65
66 struct inet_timewait_death_row {
67 /* Short-time timewait calendar */
68 int twcal_hand;
69 unsigned long twcal_jiffie;
70 struct timer_list twcal_timer;
71 struct hlist_head twcal_row[INET_TWDR_RECYCLE_SLOTS];
72
73 spinlock_t death_lock;
74 int tw_count;
75 int period;
76 u32 thread_slots;
77 struct work_struct twkill_work;
78 struct timer_list tw_timer;
79 int slot;
80 struct hlist_head cells[INET_TWDR_TWKILL_SLOTS];
81 struct inet_hashinfo *hashinfo;
82 int sysctl_tw_recycle;
83 int sysctl_max_tw_buckets;
84 };
85
86 extern void inet_twdr_hangman(unsigned long data);
87 extern void inet_twdr_twkill_work(struct work_struct *work);
88 extern void inet_twdr_twcal_tick(unsigned long data);
89
90 #if (BITS_PER_LONG == 64)
91 #define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 8
92 #else
93 #define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 4
94 #endif
95
96 struct inet_bind_bucket;
97
98 /*
99 * This is a TIME_WAIT sock. It works around the memory consumption
100 * problems of sockets in such a state on heavily loaded servers, but
101 * without violating the protocol specification.
102 */
103 struct inet_timewait_sock {
104 /*
105 * Now struct sock also uses sock_common, so please just
106 * don't add nothing before this first member (__tw_common) --acme
107 */
108 struct sock_common __tw_common;
109 #define tw_family __tw_common.skc_family
110 #define tw_state __tw_common.skc_state
111 #define tw_reuse __tw_common.skc_reuse
112 #define tw_bound_dev_if __tw_common.skc_bound_dev_if
113 #define tw_node __tw_common.skc_node
114 #define tw_bind_node __tw_common.skc_bind_node
115 #define tw_refcnt __tw_common.skc_refcnt
116 #define tw_hash __tw_common.skc_hash
117 #define tw_prot __tw_common.skc_prot
118 #define tw_net __tw_common.skc_net
119 int tw_timeout;
120 volatile unsigned char tw_substate;
121 /* 3 bits hole, try to pack */
122 unsigned char tw_rcv_wscale;
123 /* Socket demultiplex comparisons on incoming packets. */
124 /* these five are in inet_sock */
125 __be16 tw_sport;
126 __be32 tw_daddr __attribute__((aligned(INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES)));
127 __be32 tw_rcv_saddr;
128 __be16 tw_dport;
129 __u16 tw_num;
130 /* And these are ours. */
131 __u8 tw_ipv6only:1;
132 /* 15 bits hole, try to pack */
133 __u16 tw_ipv6_offset;
134 unsigned long tw_ttd;
135 struct inet_bind_bucket *tw_tb;
136 struct hlist_node tw_death_node;
137 };
138
139 static inline void inet_twsk_add_node(struct inet_timewait_sock *tw,
140 struct hlist_head *list)
141 {
142 hlist_add_head(&tw->tw_node, list);
143 }
144
145 static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
146 struct hlist_head *list)
147 {
148 hlist_add_head(&tw->tw_bind_node, list);
149 }
150
151 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
152 {
153 return !hlist_unhashed(&tw->tw_death_node);
154 }
155
156 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
157 {
158 tw->tw_death_node.pprev = NULL;
159 }
160
161 static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
162 {
163 __hlist_del(&tw->tw_death_node);
164 inet_twsk_dead_node_init(tw);
165 }
166
167 static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
168 {
169 if (inet_twsk_dead_hashed(tw)) {
170 __inet_twsk_del_dead_node(tw);
171 return 1;
172 }
173 return 0;
174 }
175
176 #define inet_twsk_for_each(tw, node, head) \
177 hlist_for_each_entry(tw, node, head, tw_node)
178
179 #define inet_twsk_for_each_inmate(tw, node, jail) \
180 hlist_for_each_entry(tw, node, jail, tw_death_node)
181
182 #define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
183 hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
184
185 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
186 {
187 return (struct inet_timewait_sock *)sk;
188 }
189
190 static inline __be32 inet_rcv_saddr(const struct sock *sk)
191 {
192 return likely(sk->sk_state != TCP_TIME_WAIT) ?
193 inet_sk(sk)->rcv_saddr : inet_twsk(sk)->tw_rcv_saddr;
194 }
195
196 extern void inet_twsk_put(struct inet_timewait_sock *tw);
197
198 extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
199 const int state);
200
201 extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
202 struct sock *sk,
203 struct inet_hashinfo *hashinfo);
204
205 extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
206 struct inet_timewait_death_row *twdr,
207 const int timeo, const int timewait_len);
208 extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
209 struct inet_timewait_death_row *twdr);
210 #endif /* _INET_TIMEWAIT_SOCK_ */
211
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