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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> |
19 | #include <linux/spinlock.h> |
20 | #include <linux/types.h> |
21 | #include <linux/bug.h> |
22 | |
23 | #include <net/sock.h> |
24 | |
25 | struct request_sock; |
26 | struct sk_buff; |
27 | struct dst_entry; |
28 | struct proto; |
29 | |
30 | /* empty to "strongly type" an otherwise void parameter. |
31 | */ |
32 | struct request_values { |
33 | }; |
34 | |
35 | struct request_sock_ops { |
36 | int family; |
37 | int obj_size; |
38 | struct kmem_cache *slab; |
39 | char *slab_name; |
40 | int (*rtx_syn_ack)(struct sock *sk, |
41 | struct request_sock *req, |
42 | struct request_values *rvp); |
43 | void (*send_ack)(struct sock *sk, struct sk_buff *skb, |
44 | struct request_sock *req); |
45 | void (*send_reset)(struct sock *sk, |
46 | struct sk_buff *skb); |
47 | void (*destructor)(struct request_sock *req); |
48 | void (*syn_ack_timeout)(struct sock *sk, |
49 | struct request_sock *req); |
50 | }; |
51 | |
52 | /* struct request_sock - mini sock to represent a connection request |
53 | */ |
54 | struct request_sock { |
55 | struct request_sock *dl_next; /* Must be first member! */ |
56 | u16 mss; |
57 | u8 retrans; |
58 | u8 cookie_ts; /* syncookie: encode tcpopts in timestamp */ |
59 | /* The following two fields can be easily recomputed I think -AK */ |
60 | u32 window_clamp; /* window clamp at creation time */ |
61 | u32 rcv_wnd; /* rcv_wnd offered first time */ |
62 | u32 ts_recent; |
63 | unsigned long expires; |
64 | const struct request_sock_ops *rsk_ops; |
65 | struct sock *sk; |
66 | u32 secid; |
67 | u32 peer_secid; |
68 | }; |
69 | |
70 | static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops) |
71 | { |
72 | struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC); |
73 | |
74 | if (req != NULL) |
75 | req->rsk_ops = ops; |
76 | |
77 | return req; |
78 | } |
79 | |
80 | static inline void __reqsk_free(struct request_sock *req) |
81 | { |
82 | kmem_cache_free(req->rsk_ops->slab, req); |
83 | } |
84 | |
85 | static inline void reqsk_free(struct request_sock *req) |
86 | { |
87 | req->rsk_ops->destructor(req); |
88 | __reqsk_free(req); |
89 | } |
90 | |
91 | extern int sysctl_max_syn_backlog; |
92 | |
93 | /** struct listen_sock - listen state |
94 | * |
95 | * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs |
96 | */ |
97 | struct listen_sock { |
98 | u8 max_qlen_log; |
99 | /* 3 bytes hole, try to use */ |
100 | int qlen; |
101 | int qlen_young; |
102 | int clock_hand; |
103 | u32 hash_rnd; |
104 | u32 nr_table_entries; |
105 | struct request_sock *syn_table[0]; |
106 | }; |
107 | |
108 | /** struct request_sock_queue - queue of request_socks |
109 | * |
110 | * @rskq_accept_head - FIFO head of established children |
111 | * @rskq_accept_tail - FIFO tail of established children |
112 | * @rskq_defer_accept - User waits for some data after accept() |
113 | * @syn_wait_lock - serializer |
114 | * |
115 | * %syn_wait_lock is necessary only to avoid proc interface having to grab the main |
116 | * lock sock while browsing the listening hash (otherwise it's deadlock prone). |
117 | * |
118 | * This lock is acquired in read mode only from listening_get_next() seq_file |
119 | * op and it's acquired in write mode _only_ from code that is actively |
120 | * changing rskq_accept_head. All readers that are holding the master sock lock |
121 | * don't need to grab this lock in read mode too as rskq_accept_head. writes |
122 | * are always protected from the main sock lock. |
123 | */ |
124 | struct request_sock_queue { |
125 | struct request_sock *rskq_accept_head; |
126 | struct request_sock *rskq_accept_tail; |
127 | rwlock_t syn_wait_lock; |
128 | u8 rskq_defer_accept; |
129 | /* 3 bytes hole, try to pack */ |
130 | struct listen_sock *listen_opt; |
131 | }; |
132 | |
133 | extern int reqsk_queue_alloc(struct request_sock_queue *queue, |
134 | unsigned int nr_table_entries); |
135 | |
136 | extern void __reqsk_queue_destroy(struct request_sock_queue *queue); |
137 | extern void reqsk_queue_destroy(struct request_sock_queue *queue); |
138 | |
139 | static inline struct request_sock * |
140 | reqsk_queue_yank_acceptq(struct request_sock_queue *queue) |
141 | { |
142 | struct request_sock *req = queue->rskq_accept_head; |
143 | |
144 | queue->rskq_accept_head = NULL; |
145 | return req; |
146 | } |
147 | |
148 | static inline int reqsk_queue_empty(struct request_sock_queue *queue) |
149 | { |
150 | return queue->rskq_accept_head == NULL; |
151 | } |
152 | |
153 | static inline void reqsk_queue_unlink(struct request_sock_queue *queue, |
154 | struct request_sock *req, |
155 | struct request_sock **prev_req) |
156 | { |
157 | write_lock(&queue->syn_wait_lock); |
158 | *prev_req = req->dl_next; |
159 | write_unlock(&queue->syn_wait_lock); |
160 | } |
161 | |
162 | static inline void reqsk_queue_add(struct request_sock_queue *queue, |
163 | struct request_sock *req, |
164 | struct sock *parent, |
165 | struct sock *child) |
166 | { |
167 | req->sk = child; |
168 | sk_acceptq_added(parent); |
169 | |
170 | if (queue->rskq_accept_head == NULL) |
171 | queue->rskq_accept_head = req; |
172 | else |
173 | queue->rskq_accept_tail->dl_next = req; |
174 | |
175 | queue->rskq_accept_tail = req; |
176 | req->dl_next = NULL; |
177 | } |
178 | |
179 | static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue) |
180 | { |
181 | struct request_sock *req = queue->rskq_accept_head; |
182 | |
183 | WARN_ON(req == NULL); |
184 | |
185 | queue->rskq_accept_head = req->dl_next; |
186 | if (queue->rskq_accept_head == NULL) |
187 | queue->rskq_accept_tail = NULL; |
188 | |
189 | return req; |
190 | } |
191 | |
192 | static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue, |
193 | struct sock *parent) |
194 | { |
195 | struct request_sock *req = reqsk_queue_remove(queue); |
196 | struct sock *child = req->sk; |
197 | |
198 | WARN_ON(child == NULL); |
199 | |
200 | sk_acceptq_removed(parent); |
201 | __reqsk_free(req); |
202 | return child; |
203 | } |
204 | |
205 | static inline int reqsk_queue_removed(struct request_sock_queue *queue, |
206 | struct request_sock *req) |
207 | { |
208 | struct listen_sock *lopt = queue->listen_opt; |
209 | |
210 | if (req->retrans == 0) |
211 | --lopt->qlen_young; |
212 | |
213 | return --lopt->qlen; |
214 | } |
215 | |
216 | static inline int reqsk_queue_added(struct request_sock_queue *queue) |
217 | { |
218 | struct listen_sock *lopt = queue->listen_opt; |
219 | const int prev_qlen = lopt->qlen; |
220 | |
221 | lopt->qlen_young++; |
222 | lopt->qlen++; |
223 | return prev_qlen; |
224 | } |
225 | |
226 | static inline int reqsk_queue_len(const struct request_sock_queue *queue) |
227 | { |
228 | return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0; |
229 | } |
230 | |
231 | static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) |
232 | { |
233 | return queue->listen_opt->qlen_young; |
234 | } |
235 | |
236 | static inline int reqsk_queue_is_full(const struct request_sock_queue *queue) |
237 | { |
238 | return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log; |
239 | } |
240 | |
241 | static inline void reqsk_queue_hash_req(struct request_sock_queue *queue, |
242 | u32 hash, struct request_sock *req, |
243 | unsigned long timeout) |
244 | { |
245 | struct listen_sock *lopt = queue->listen_opt; |
246 | |
247 | req->expires = jiffies + timeout; |
248 | req->retrans = 0; |
249 | req->sk = NULL; |
250 | req->dl_next = lopt->syn_table[hash]; |
251 | |
252 | write_lock(&queue->syn_wait_lock); |
253 | lopt->syn_table[hash] = req; |
254 | write_unlock(&queue->syn_wait_lock); |
255 | } |
256 | |
257 | #endif /* _REQUEST_SOCK_H */ |
258 |
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