Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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 #if (BITS_PER_LONG == 64)
 92 #define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 8
 93 #else
 94 #define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 4
 95 #endif
 96 
 97 struct inet_bind_bucket;
 98 
 99 /*
100  * This is a TIME_WAIT sock. It works around the memory consumption
101  * problems of sockets in such a state on heavily loaded servers, but
102  * without violating the protocol specification.
103  */
104 struct inet_timewait_sock {
105         /*
106          * Now struct sock also uses sock_common, so please just
107          * don't add nothing before this first member (__tw_common) --acme
108          */
109         struct sock_common      __tw_common;
110 #define tw_family               __tw_common.skc_family
111 #define tw_state                __tw_common.skc_state
112 #define tw_reuse                __tw_common.skc_reuse
113 #define tw_bound_dev_if         __tw_common.skc_bound_dev_if
114 #define tw_node                 __tw_common.skc_nulls_node
115 #define tw_bind_node            __tw_common.skc_bind_node
116 #define tw_refcnt               __tw_common.skc_refcnt
117 #define tw_hash                 __tw_common.skc_hash
118 #define tw_prot                 __tw_common.skc_prot
119 #define tw_net                  __tw_common.skc_net
120         int                     tw_timeout;
121         volatile unsigned char  tw_substate;
122         /* 3 bits hole, try to pack */
123         unsigned char           tw_rcv_wscale;
124         /* Socket demultiplex comparisons on incoming packets. */
125         /* these five are in inet_sock */
126         __be16                  tw_sport;
127         __be32                  tw_daddr __attribute__((aligned(INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES)));
128         __be32                  tw_rcv_saddr;
129         __be16                  tw_dport;
130         __u16                   tw_num;
131         kmemcheck_bitfield_begin(flags);
132         /* And these are ours. */
133         __u8                    tw_ipv6only:1,
134                                 tw_transparent:1;
135         /* 14 bits hole, try to pack */
136         kmemcheck_bitfield_end(flags);
137         __u16                   tw_ipv6_offset;
138         unsigned long           tw_ttd;
139         struct inet_bind_bucket *tw_tb;
140         struct hlist_node       tw_death_node;
141 };
142 
143 static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
144                                       struct hlist_nulls_head *list)
145 {
146         hlist_nulls_add_head_rcu(&tw->tw_node, list);
147 }
148 
149 static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
150                                            struct hlist_head *list)
151 {
152         hlist_add_head(&tw->tw_bind_node, list);
153 }
154 
155 static inline int inet_twsk_dead_hashed(const struct inet_timewait_sock *tw)
156 {
157         return !hlist_unhashed(&tw->tw_death_node);
158 }
159 
160 static inline void inet_twsk_dead_node_init(struct inet_timewait_sock *tw)
161 {
162         tw->tw_death_node.pprev = NULL;
163 }
164 
165 static inline void __inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
166 {
167         __hlist_del(&tw->tw_death_node);
168         inet_twsk_dead_node_init(tw);
169 }
170 
171 static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
172 {
173         if (inet_twsk_dead_hashed(tw)) {
174                 __inet_twsk_del_dead_node(tw);
175                 return 1;
176         }
177         return 0;
178 }
179 
180 #define inet_twsk_for_each(tw, node, head) \
181         hlist_nulls_for_each_entry(tw, node, head, tw_node)
182 
183 #define inet_twsk_for_each_inmate(tw, node, jail) \
184         hlist_for_each_entry(tw, node, jail, tw_death_node)
185 
186 #define inet_twsk_for_each_inmate_safe(tw, node, safe, jail) \
187         hlist_for_each_entry_safe(tw, node, safe, jail, tw_death_node)
188 
189 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
190 {
191         return (struct inet_timewait_sock *)sk;
192 }
193 
194 static inline __be32 inet_rcv_saddr(const struct sock *sk)
195 {
196         return likely(sk->sk_state != TCP_TIME_WAIT) ?
197                 inet_sk(sk)->rcv_saddr : inet_twsk(sk)->tw_rcv_saddr;
198 }
199 
200 extern void inet_twsk_put(struct inet_timewait_sock *tw);
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 net *net, 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 #ifdef CONFIG_NET_NS
222         return twsk->tw_net;
223 #else
224         return &init_net;
225 #endif
226 }
227 
228 static inline
229 void twsk_net_set(struct inet_timewait_sock *twsk, struct net *net)
230 {
231 #ifdef CONFIG_NET_NS
232         twsk->tw_net = net;
233 #endif
234 }
235 #endif  /* _INET_TIMEWAIT_SOCK_ */
236 
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