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/module.h>
22 #include <linux/timer.h>
23 #include <linux/types.h>
24 #include <linux/workqueue.h>
25
26 #include <net/inet_sock.h>
27 #include <net/sock.h>
28 #include <net/tcp_states.h>
29 #include <net/timewait_sock.h>
30
31 #include <asm/atomic.h>
32
33 struct inet_hashinfo;
34
35 #define INET_TWDR_RECYCLE_SLOTS_LOG 5
36 #define INET_TWDR_RECYCLE_SLOTS (1 << INET_TWDR_RECYCLE_SLOTS_LOG)
37
38 /*
39 * If time > 4sec, it is "slow" path, no recycling is required,
40 * so that we select tick to get range about 4 seconds.
41 */
42 #if HZ <= 16 || HZ > 4096
43 # error Unsupported: HZ <= 16 or HZ > 4096
44 #elif HZ <= 32
45 # define INET_TWDR_RECYCLE_TICK (5 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
46 #elif HZ <= 64
47 # define INET_TWDR_RECYCLE_TICK (6 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
48 #elif HZ <= 128
49 # define INET_TWDR_RECYCLE_TICK (7 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
50 #elif HZ <= 256
51 # define INET_TWDR_RECYCLE_TICK (8 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
52 #elif HZ <= 512
53 # define INET_TWDR_RECYCLE_TICK (9 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
54 #elif HZ <= 1024
55 # define INET_TWDR_RECYCLE_TICK (10 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
56 #elif HZ <= 2048
57 # define INET_TWDR_RECYCLE_TICK (11 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
58 #else
59 # define INET_TWDR_RECYCLE_TICK (12 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
60 #endif
61
62 /* TIME_WAIT reaping mechanism. */
63 #define INET_TWDR_TWKILL_SLOTS 8 /* Please keep this a power of 2. */
64
65 #define INET_TWDR_TWKILL_QUOTA 100
66
67 struct inet_timewait_death_row {
68 /* Short-time timewait calendar */
69 int twcal_hand;
70 unsigned long twcal_jiffie;
71 struct timer_list twcal_timer;
72 struct hlist_head twcal_row[INET_TWDR_RECYCLE_SLOTS];
73
74 spinlock_t death_lock;
75 int tw_count;
76 int period;
77 u32 thread_slots;
78 struct work_struct twkill_work;
79 struct timer_list tw_timer;
80 int slot;
81 struct hlist_head cells[INET_TWDR_TWKILL_SLOTS];
82 struct inet_hashinfo *hashinfo;
83 int sysctl_tw_recycle;
84 int sysctl_max_tw_buckets;
85 };
86
87 extern void inet_twdr_hangman(unsigned long data);
88 extern void inet_twdr_twkill_work(struct work_struct *work);
89 extern void inet_twdr_twcal_tick(unsigned long data);
90
91 struct inet_bind_bucket;
92
93 /*
94 * This is a TIME_WAIT sock. It works around the memory consumption
95 * problems of sockets in such a state on heavily loaded servers, but
96 * without violating the protocol specification.
97 */
98 struct inet_timewait_sock {
99 /*
100 * Now struct sock also uses sock_common, so please just
101 * don't add nothing before this first member (__tw_common) --acme
102 */
103 struct sock_common __tw_common;
104 #define tw_family __tw_common.skc_family
105 #define tw_state __tw_common.skc_state
106 #define tw_reuse __tw_common.skc_reuse
107 #define tw_bound_dev_if __tw_common.skc_bound_dev_if
108 #define tw_node __tw_common.skc_nulls_node
109 #define tw_bind_node __tw_common.skc_bind_node
110 #define tw_refcnt __tw_common.skc_refcnt
111 #define tw_hash __tw_common.skc_hash
112 #define tw_prot __tw_common.skc_prot
113 #define tw_net __tw_common.skc_net
114 #define tw_daddr __tw_common.skc_daddr
115 #define tw_rcv_saddr __tw_common.skc_rcv_saddr
116 int tw_timeout;
117 volatile unsigned char tw_substate;
118 unsigned char tw_rcv_wscale;
119
120 /* Socket demultiplex comparisons on incoming packets. */
121 /* these three are in inet_sock */
122 __be16 tw_sport;
123 __be16 tw_dport;
124 __u16 tw_num;
125 kmemcheck_bitfield_begin(flags);
126 /* And these are ours. */
127 unsigned int tw_ipv6only : 1,
128 tw_transparent : 1,
129 tw_pad : 14, /* 14 bits hole */
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
inet_twsk_add_node_rcu(struct inet_timewait_sock * tw,struct hlist_nulls_head * list)137 static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
138 struct hlist_nulls_head *list)
139 {
140 hlist_nulls_add_head_rcu(&tw->tw_node, list);
141 }
142
inet_twsk_add_bind_node(struct inet_timewait_sock * tw,struct hlist_head * list)143 static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
144 struct hlist_head *list)
145 {
146 hlist_add_head(&tw->tw_bind_node, list);
147 }
148
inet_twsk_dead_hashed(const struct inet_timewait_sock * tw)149 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
150 {
151 return !hlist_unhashed(&tw->tw_death_node);
152 }
153
inet_twsk_dead_node_init(struct inet_timewait_sock * tw)154 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
155 {
156 tw->tw_death_node.pprev = NULL;
157 }
158
__inet_twsk_del_dead_node(struct inet_timewait_sock * tw)159 static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
160 {
161 __hlist_del(&tw->tw_death_node);
162 inet_twsk_dead_node_init(tw);
163 }
164
inet_twsk_del_dead_node(struct inet_timewait_sock * tw)165 static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
166 {
167 if (inet_twsk_dead_hashed(tw)) {
168 __inet_twsk_del_dead_node(tw);
169 return 1;
170 }
171 return 0;
172 }
173
174 #define inet_twsk_for_each(tw, node, head) \
175 hlist_nulls_for_each_entry(tw, node, head, tw_node)
176
177 #define inet_twsk_for_each_inmate(tw, node, jail) \
178 hlist_for_each_entry(tw, node, jail, tw_death_node)
179
180 #define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
181 hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
182
inet_twsk(const struct sock * sk)183 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
184 {
185 return (struct inet_timewait_sock *)sk;
186 }
187
sk_rcv_saddr(const struct sock * sk)188 static inline __be32 sk_rcv_saddr(const struct sock *sk)
189 {
190 /* both inet_sk() and inet_twsk() store rcv_saddr in skc_rcv_saddr */
191 return sk->__sk_common.skc_rcv_saddr;
192 }
193
194 extern void inet_twsk_put(struct inet_timewait_sock *tw);
195
196 extern int inet_twsk_unhash(struct inet_timewait_sock *tw);
197
198 extern int inet_twsk_bind_unhash(struct inet_timewait_sock *tw,
199 struct inet_hashinfo *hashinfo);
200
201 extern struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
202 const int state);
203
204 extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,
205 struct sock *sk,
206 struct inet_hashinfo *hashinfo);
207
208 extern void inet_twsk_schedule(struct inet_timewait_sock *tw,
209 struct inet_timewait_death_row *twdr,
210 const int timeo, const int timewait_len);
211 extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,
212 struct inet_timewait_death_row *twdr);
213
214 extern void inet_twsk_purge(struct inet_hashinfo *hashinfo,
215 struct inet_timewait_death_row *twdr, int family);
216
217 static inline
twsk_net(const struct inet_timewait_sock * twsk)218 struct net *twsk_net(const struct inet_timewait_sock *twsk)
219 {
220 #ifdef CONFIG_NET_NS
221 return rcu_dereference_raw(twsk->tw_net); /* protected by locking, */
222 /* reference counting, */
223 /* initialization, or RCU. */
224 #else
225 return &init_net;
226 #endif
227 }
228
229 static inline
twsk_net_set(struct inet_timewait_sock * twsk,struct net * net)230 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
231 {
232 #ifdef CONFIG_NET_NS
233 rcu_assign_pointer(twsk->tw_net, net);
234 #endif
235 }
236 #endif /* _INET_TIMEWAIT_SOCK_ */
237