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inet_timewait_sock.h
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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 #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 struct inet_bind_bucket;
91 
92 /*
93  * This is a TIME_WAIT sock. It works around the memory consumption
94  * problems of sockets in such a state on heavily loaded servers, but
95  * without violating the protocol specification.
96  */
97 struct inet_timewait_sock {
98  /*
99  * Now struct sock also uses sock_common, so please just
100  * don't add nothing before this first member (__tw_common) --acme
101  */
102  struct sock_common __tw_common;
103 #define tw_family __tw_common.skc_family
104 #define tw_state __tw_common.skc_state
105 #define tw_reuse __tw_common.skc_reuse
106 #define tw_bound_dev_if __tw_common.skc_bound_dev_if
107 #define tw_node __tw_common.skc_nulls_node
108 #define tw_bind_node __tw_common.skc_bind_node
109 #define tw_refcnt __tw_common.skc_refcnt
110 #define tw_hash __tw_common.skc_hash
111 #define tw_prot __tw_common.skc_prot
112 #define tw_net __tw_common.skc_net
113 #define tw_daddr __tw_common.skc_daddr
114 #define tw_rcv_saddr __tw_common.skc_rcv_saddr
115  int tw_timeout;
116  volatile unsigned char tw_substate;
117  unsigned char tw_rcv_wscale;
118 
119  /* Socket demultiplex comparisons on incoming packets. */
120  /* these three are in inet_sock */
121  __be16 tw_sport;
122  __be16 tw_dport;
123  __u16 tw_num;
124  kmemcheck_bitfield_begin(flags);
125  /* And these are ours. */
126  unsigned int tw_ipv6only : 1,
127  tw_transparent : 1,
128  tw_pad : 6, /* 6 bits hole */
129  tw_tos : 8,
130  tw_ipv6_offset : 16;
131  kmemcheck_bitfield_end(flags);
132  unsigned long tw_ttd;
133  struct inet_bind_bucket *tw_tb;
134  struct hlist_node tw_death_node;
135 };
136 #define tw_tclass tw_tos
137 
138 static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
139  struct hlist_nulls_head *list)
140 {
141  hlist_nulls_add_head_rcu(&tw->tw_node, list);
142 }
143 
144 static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
145  struct hlist_head *list)
146 {
147  hlist_add_head(&tw->tw_bind_node, list);
148 }
149 
150 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
151 {
152  return !hlist_unhashed(&tw->tw_death_node);
153 }
154 
155 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
156 {
157  tw->tw_death_node.pprev = NULL;
158 }
159 
160 static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
161 {
162  __hlist_del(&tw->tw_death_node);
163  inet_twsk_dead_node_init(tw);
164 }
165 
166 static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
167 {
168  if (inet_twsk_dead_hashed(tw)) {
169  __inet_twsk_del_dead_node(tw);
170  return 1;
171  }
172  return 0;
173 }
174 
175 #define inet_twsk_for_each(tw, node, head) \
176  hlist_nulls_for_each_entry(tw, node, head, tw_node)
177 
178 #define inet_twsk_for_each_inmate(tw, node, jail) \
179  hlist_for_each_entry(tw, node, jail, tw_death_node)
180 
181 #define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
182  hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
183 
184 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
185 {
186  return (struct inet_timewait_sock *)sk;
187 }
188 
189 static inline __be32 sk_rcv_saddr(const struct sock *sk)
190 {
191 /* both inet_sk() and inet_twsk() store rcv_saddr in skc_rcv_saddr */
192  return sk->__sk_common.skc_rcv_saddr;
193 }
194 
195 extern void inet_twsk_put(struct inet_timewait_sock *tw);
196 
197 extern int inet_twsk_unhash(struct inet_timewait_sock *tw);
198 
199 extern int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
200  struct inet_hashinfo *hashinfo);
201 
202 extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
203  const int state);
204 
205 extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
206  struct sock *sk,
207  struct inet_hashinfo *hashinfo);
208 
209 extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
210  struct inet_timewait_death_row *twdr,
211  const int timeo, const int timewait_len);
212 extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
213  struct inet_timewait_death_row *twdr);
214 
215 extern void inet_twsk_purge(struct inet_hashinfo *hashinfo,
216  struct inet_timewait_death_row *twdr, int family);
217 
218 static inline
219 struct net *twsk_net(const struct inet_timewait_sock *twsk)
220 {
221  return read_pnet(&twsk->tw_net);
222 }
223 
224 static inline
225 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
226 {
227  write_pnet(&twsk->tw_net, net);
228 }
229 #endif /* _INET_TIMEWAIT_SOCK_ */
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