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2e6599cb ACM |
1 | /* |
2 | * NET Generic infrastructure for Network protocols. | |
3 | * | |
4 | * Definitions for request_sock | |
5 | * | |
6 | * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br> | |
7 | * | |
8 | * From code originally in include/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 _REQUEST_SOCK_H | |
16 | #define _REQUEST_SOCK_H | |
17 | ||
18 | #include <linux/slab.h> | |
0e87506f | 19 | #include <linux/spinlock.h> |
2e6599cb | 20 | #include <linux/types.h> |
0e87506f | 21 | |
2e6599cb ACM |
22 | #include <net/sock.h> |
23 | ||
60236fdd | 24 | struct request_sock; |
2e6599cb ACM |
25 | struct sk_buff; |
26 | struct dst_entry; | |
27 | struct proto; | |
28 | ||
60236fdd | 29 | struct request_sock_ops { |
2e6599cb ACM |
30 | int family; |
31 | kmem_cache_t *slab; | |
32 | int obj_size; | |
33 | int (*rtx_syn_ack)(struct sock *sk, | |
60236fdd | 34 | struct request_sock *req, |
2e6599cb ACM |
35 | struct dst_entry *dst); |
36 | void (*send_ack)(struct sk_buff *skb, | |
60236fdd | 37 | struct request_sock *req); |
2e6599cb | 38 | void (*send_reset)(struct sk_buff *skb); |
60236fdd | 39 | void (*destructor)(struct request_sock *req); |
2e6599cb ACM |
40 | }; |
41 | ||
60236fdd | 42 | /* struct request_sock - mini sock to represent a connection request |
2e6599cb | 43 | */ |
60236fdd ACM |
44 | struct request_sock { |
45 | struct request_sock *dl_next; /* Must be first member! */ | |
2e6599cb ACM |
46 | u16 mss; |
47 | u8 retrans; | |
48 | u8 __pad; | |
49 | /* The following two fields can be easily recomputed I think -AK */ | |
50 | u32 window_clamp; /* window clamp at creation time */ | |
51 | u32 rcv_wnd; /* rcv_wnd offered first time */ | |
52 | u32 ts_recent; | |
53 | unsigned long expires; | |
60236fdd | 54 | struct request_sock_ops *rsk_ops; |
2e6599cb ACM |
55 | struct sock *sk; |
56 | }; | |
57 | ||
60236fdd | 58 | static inline struct request_sock *reqsk_alloc(struct request_sock_ops *ops) |
2e6599cb | 59 | { |
60236fdd | 60 | struct request_sock *req = kmem_cache_alloc(ops->slab, SLAB_ATOMIC); |
2e6599cb ACM |
61 | |
62 | if (req != NULL) | |
60236fdd | 63 | req->rsk_ops = ops; |
2e6599cb ACM |
64 | |
65 | return req; | |
66 | } | |
67 | ||
60236fdd | 68 | static inline void __reqsk_free(struct request_sock *req) |
2e6599cb | 69 | { |
60236fdd | 70 | kmem_cache_free(req->rsk_ops->slab, req); |
2e6599cb ACM |
71 | } |
72 | ||
60236fdd | 73 | static inline void reqsk_free(struct request_sock *req) |
2e6599cb | 74 | { |
60236fdd ACM |
75 | req->rsk_ops->destructor(req); |
76 | __reqsk_free(req); | |
2e6599cb ACM |
77 | } |
78 | ||
0e87506f ACM |
79 | extern int sysctl_max_syn_backlog; |
80 | ||
81 | /** struct tcp_listen_opt - listen state | |
82 | * | |
83 | * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs | |
84 | */ | |
85 | struct tcp_listen_opt { | |
86 | u8 max_qlen_log; | |
87 | /* 3 bytes hole, try to use */ | |
88 | int qlen; | |
89 | int qlen_young; | |
90 | int clock_hand; | |
91 | u32 hash_rnd; | |
92 | struct request_sock *syn_table[0]; | |
93 | }; | |
94 | ||
95 | /** struct request_sock_queue - queue of request_socks | |
96 | * | |
97 | * @rskq_accept_head - FIFO head of established children | |
98 | * @rskq_accept_tail - FIFO tail of established children | |
99 | * @syn_wait_lock - serializer | |
100 | * | |
101 | * %syn_wait_lock is necessary only to avoid proc interface having to grab the main | |
102 | * lock sock while browsing the listening hash (otherwise it's deadlock prone). | |
103 | * | |
104 | * This lock is acquired in read mode only from listening_get_next() seq_file | |
105 | * op and it's acquired in write mode _only_ from code that is actively | |
106 | * changing rskq_accept_head. All readers that are holding the master sock lock | |
107 | * don't need to grab this lock in read mode too as rskq_accept_head. writes | |
108 | * are always protected from the main sock lock. | |
109 | */ | |
110 | struct request_sock_queue { | |
111 | struct request_sock *rskq_accept_head; | |
112 | struct request_sock *rskq_accept_tail; | |
113 | rwlock_t syn_wait_lock; | |
114 | struct tcp_listen_opt *listen_opt; | |
115 | }; | |
116 | ||
117 | extern int reqsk_queue_alloc(struct request_sock_queue *queue, | |
118 | const int nr_table_entries); | |
119 | ||
120 | static inline struct tcp_listen_opt *reqsk_queue_yank_listen_sk(struct request_sock_queue *queue) | |
121 | { | |
122 | struct tcp_listen_opt *lopt; | |
123 | ||
124 | write_lock_bh(&queue->syn_wait_lock); | |
125 | lopt = queue->listen_opt; | |
126 | queue->listen_opt = NULL; | |
127 | write_unlock_bh(&queue->syn_wait_lock); | |
128 | ||
129 | return lopt; | |
130 | } | |
131 | ||
132 | static inline void reqsk_queue_destroy(struct request_sock_queue *queue) | |
133 | { | |
134 | kfree(reqsk_queue_yank_listen_sk(queue)); | |
135 | } | |
136 | ||
137 | static inline struct request_sock * | |
138 | reqsk_queue_yank_acceptq(struct request_sock_queue *queue) | |
139 | { | |
140 | struct request_sock *req = queue->rskq_accept_head; | |
141 | ||
142 | queue->rskq_accept_head = queue->rskq_accept_head = NULL; | |
143 | return req; | |
144 | } | |
145 | ||
146 | static inline int reqsk_queue_empty(struct request_sock_queue *queue) | |
147 | { | |
148 | return queue->rskq_accept_head == NULL; | |
149 | } | |
150 | ||
151 | static inline void reqsk_queue_unlink(struct request_sock_queue *queue, | |
152 | struct request_sock *req, | |
153 | struct request_sock **prev_req) | |
154 | { | |
155 | write_lock(&queue->syn_wait_lock); | |
156 | *prev_req = req->dl_next; | |
157 | write_unlock(&queue->syn_wait_lock); | |
158 | } | |
159 | ||
160 | static inline void reqsk_queue_add(struct request_sock_queue *queue, | |
161 | struct request_sock *req, | |
162 | struct sock *parent, | |
163 | struct sock *child) | |
164 | { | |
165 | req->sk = child; | |
166 | sk_acceptq_added(parent); | |
167 | ||
168 | if (queue->rskq_accept_head == NULL) | |
169 | queue->rskq_accept_head = req; | |
170 | else | |
171 | queue->rskq_accept_tail->dl_next = req; | |
172 | ||
173 | queue->rskq_accept_tail = req; | |
174 | req->dl_next = NULL; | |
175 | } | |
176 | ||
177 | static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue) | |
178 | { | |
179 | struct request_sock *req = queue->rskq_accept_head; | |
180 | ||
181 | BUG_TRAP(req != NULL); | |
182 | ||
183 | queue->rskq_accept_head = req->dl_next; | |
184 | if (queue->rskq_accept_head == NULL) | |
185 | queue->rskq_accept_tail = NULL; | |
186 | ||
187 | return req; | |
188 | } | |
189 | ||
190 | static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue, | |
191 | struct sock *parent) | |
192 | { | |
193 | struct request_sock *req = reqsk_queue_remove(queue); | |
194 | struct sock *child = req->sk; | |
195 | ||
196 | BUG_TRAP(child != NULL); | |
197 | ||
198 | sk_acceptq_removed(parent); | |
199 | __reqsk_free(req); | |
200 | return child; | |
201 | } | |
202 | ||
203 | static inline int reqsk_queue_removed(struct request_sock_queue *queue, | |
204 | struct request_sock *req) | |
205 | { | |
206 | struct tcp_listen_opt *lopt = queue->listen_opt; | |
207 | ||
208 | if (req->retrans == 0) | |
209 | --lopt->qlen_young; | |
210 | ||
211 | return --lopt->qlen; | |
212 | } | |
213 | ||
214 | static inline int reqsk_queue_added(struct request_sock_queue *queue) | |
215 | { | |
216 | struct tcp_listen_opt *lopt = queue->listen_opt; | |
217 | const int prev_qlen = lopt->qlen; | |
218 | ||
219 | lopt->qlen_young++; | |
220 | lopt->qlen++; | |
221 | return prev_qlen; | |
222 | } | |
223 | ||
224 | static inline int reqsk_queue_len(struct request_sock_queue *queue) | |
225 | { | |
226 | return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0; | |
227 | } | |
228 | ||
229 | static inline int reqsk_queue_len_young(struct request_sock_queue *queue) | |
230 | { | |
231 | return queue->listen_opt->qlen_young; | |
232 | } | |
233 | ||
234 | static inline int reqsk_queue_is_full(struct request_sock_queue *queue) | |
235 | { | |
236 | return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log; | |
237 | } | |
238 | ||
239 | static inline void reqsk_queue_hash_req(struct request_sock_queue *queue, | |
240 | u32 hash, struct request_sock *req, | |
241 | unsigned timeout) | |
242 | { | |
243 | struct tcp_listen_opt *lopt = queue->listen_opt; | |
244 | ||
245 | req->expires = jiffies + timeout; | |
246 | req->retrans = 0; | |
247 | req->sk = NULL; | |
248 | req->dl_next = lopt->syn_table[hash]; | |
249 | ||
250 | write_lock(&queue->syn_wait_lock); | |
251 | lopt->syn_table[hash] = req; | |
252 | write_unlock(&queue->syn_wait_lock); | |
253 | } | |
254 | ||
2e6599cb | 255 | #endif /* _REQUEST_SOCK_H */ |