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
inet_twsk_add_node_rcu(struct inet_timewait_sock * tw,struct hlist_nulls_head * list)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
inet_twsk_add_bind_node(struct inet_timewait_sock * tw,struct hlist_head * list)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
inet_twsk_dead_hashed(const struct inet_timewait_sock * tw)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
inet_twsk_dead_node_init(struct inet_timewait_sock * tw)155 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
156 {
157 tw->tw_death_node.pprev = NULL;
158 }
159
__inet_twsk_del_dead_node(struct inet_timewait_sock * tw)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
inet_twsk_del_dead_node(struct inet_timewait_sock * tw)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
inet_twsk(const struct sock * sk)184 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
185 {
186 return (struct inet_timewait_sock *)sk;
187 }
188
sk_rcv_saddr(const struct sock * sk)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
twsk_net(const struct inet_timewait_sock * twsk)219 struct net *twsk_net(const struct inet_timewait_sock *twsk)
220 {
221 return read_pnet(&twsk->tw_net);
222 }
223
224 static inline
twsk_net_set(struct inet_timewait_sock * twsk,struct net * net)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_ */
230