Line data Source code
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 : };
49 1 :
50 : /* struct request_sock - mini sock to represent a connection request
51 : */
52 : struct request_sock {
53 : struct request_sock *dl_next; /* Must be first member! */
54 : u16 mss;
55 : u8 retrans;
56 : u8 cookie_ts; /* syncookie: encode tcpopts in timestamp */
57 : /* The following two fields can be easily recomputed I think -AK */
58 : u32 window_clamp; /* window clamp at creation time */
59 : u32 rcv_wnd; /* rcv_wnd offered first time */
60 : u32 ts_recent;
61 : unsigned long expires;
62 : const struct request_sock_ops *rsk_ops;
63 : struct sock *sk;
64 : u32 secid;
65 : u32 peer_secid;
66 : };
67 :
68 : static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
69 : {
70 : struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
71 :
72 : if (req != NULL)
73 : req->rsk_ops = ops;
74 :
75 : return req;
76 : }
77 :
78 : static inline void __reqsk_free(struct request_sock *req)
79 : {
80 : kmem_cache_free(req->rsk_ops->slab, req);
81 : }
82 :
83 : static inline void reqsk_free(struct request_sock *req)
84 : {
85 : req->rsk_ops->destructor(req);
86 : __reqsk_free(req);
87 : }
88 :
89 : extern int sysctl_max_syn_backlog;
90 1 :
91 : /** struct listen_sock - listen state
92 : *
93 : * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
94 : */
95 : struct listen_sock {
96 : u8 max_qlen_log;
97 : /* 3 bytes hole, try to use */
98 : int qlen;
99 : int qlen_young;
100 : int clock_hand;
101 : u32 hash_rnd;
102 : u32 nr_table_entries;
103 : struct request_sock *syn_table[0];
104 : };
105 1 :
106 : /** struct request_sock_queue - queue of request_socks
107 : *
108 : * @rskq_accept_head - FIFO head of established children
109 : * @rskq_accept_tail - FIFO tail of established children
110 : * @rskq_defer_accept - User waits for some data after accept()
111 : * @syn_wait_lock - serializer
112 : *
113 : * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
114 : * lock sock while browsing the listening hash (otherwise it's deadlock prone).
115 : *
116 : * This lock is acquired in read mode only from listening_get_next() seq_file
117 : * op and it's acquired in write mode _only_ from code that is actively
118 : * changing rskq_accept_head. All readers that are holding the master sock lock
119 : * don't need to grab this lock in read mode too as rskq_accept_head. writes
120 : * are always protected from the main sock lock.
121 : */
122 : struct request_sock_queue {
123 : struct request_sock *rskq_accept_head;
124 : struct request_sock *rskq_accept_tail;
125 : rwlock_t syn_wait_lock;
126 : u8 rskq_defer_accept;
127 : /* 3 bytes hole, try to pack */
128 : struct listen_sock *listen_opt;
129 : };
130 :
131 : extern int reqsk_queue_alloc(struct request_sock_queue *queue,
132 : unsigned int nr_table_entries);
133 :
134 : extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
135 : extern void reqsk_queue_destroy(struct request_sock_queue *queue);
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 = 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 : WARN_ON(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 : WARN_ON(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 listen_sock *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 listen_sock *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(const 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(const struct request_sock_queue *queue)
230 : {
231 : return queue->listen_opt->qlen_young;
232 : }
233 :
234 : static inline int reqsk_queue_is_full(const 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 long timeout)
242 : {
243 : struct listen_sock *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 :
255 : #endif /* _REQUEST_SOCK_H */
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