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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 | ||
2ad69c55 | 81 | /** struct listen_sock - listen state |
0e87506f ACM |
82 | * |
83 | * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs | |
84 | */ | |
2ad69c55 | 85 | struct listen_sock { |
0e87506f ACM |
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; | |
83e3609e | 92 | u32 nr_table_entries; |
0e87506f ACM |
93 | struct request_sock *syn_table[0]; |
94 | }; | |
95 | ||
96 | /** struct request_sock_queue - queue of request_socks | |
97 | * | |
98 | * @rskq_accept_head - FIFO head of established children | |
99 | * @rskq_accept_tail - FIFO tail of established children | |
100 | * @syn_wait_lock - serializer | |
101 | * | |
102 | * %syn_wait_lock is necessary only to avoid proc interface having to grab the main | |
103 | * lock sock while browsing the listening hash (otherwise it's deadlock prone). | |
104 | * | |
105 | * This lock is acquired in read mode only from listening_get_next() seq_file | |
106 | * op and it's acquired in write mode _only_ from code that is actively | |
107 | * changing rskq_accept_head. All readers that are holding the master sock lock | |
108 | * don't need to grab this lock in read mode too as rskq_accept_head. writes | |
109 | * are always protected from the main sock lock. | |
110 | */ | |
111 | struct request_sock_queue { | |
112 | struct request_sock *rskq_accept_head; | |
113 | struct request_sock *rskq_accept_tail; | |
114 | rwlock_t syn_wait_lock; | |
2ad69c55 | 115 | struct listen_sock *listen_opt; |
0e87506f ACM |
116 | }; |
117 | ||
118 | extern int reqsk_queue_alloc(struct request_sock_queue *queue, | |
119 | const int nr_table_entries); | |
120 | ||
2ad69c55 | 121 | static inline struct listen_sock *reqsk_queue_yank_listen_sk(struct request_sock_queue *queue) |
0e87506f | 122 | { |
2ad69c55 | 123 | struct listen_sock *lopt; |
0e87506f ACM |
124 | |
125 | write_lock_bh(&queue->syn_wait_lock); | |
126 | lopt = queue->listen_opt; | |
127 | queue->listen_opt = NULL; | |
128 | write_unlock_bh(&queue->syn_wait_lock); | |
129 | ||
130 | return lopt; | |
131 | } | |
132 | ||
83e3609e | 133 | static inline void __reqsk_queue_destroy(struct request_sock_queue *queue) |
0e87506f ACM |
134 | { |
135 | kfree(reqsk_queue_yank_listen_sk(queue)); | |
136 | } | |
137 | ||
83e3609e ACM |
138 | extern void reqsk_queue_destroy(struct request_sock_queue *queue); |
139 | ||
0e87506f ACM |
140 | static inline struct request_sock * |
141 | reqsk_queue_yank_acceptq(struct request_sock_queue *queue) | |
142 | { | |
143 | struct request_sock *req = queue->rskq_accept_head; | |
144 | ||
145 | queue->rskq_accept_head = queue->rskq_accept_head = NULL; | |
146 | return req; | |
147 | } | |
148 | ||
149 | static inline int reqsk_queue_empty(struct request_sock_queue *queue) | |
150 | { | |
151 | return queue->rskq_accept_head == NULL; | |
152 | } | |
153 | ||
154 | static inline void reqsk_queue_unlink(struct request_sock_queue *queue, | |
155 | struct request_sock *req, | |
156 | struct request_sock **prev_req) | |
157 | { | |
158 | write_lock(&queue->syn_wait_lock); | |
159 | *prev_req = req->dl_next; | |
160 | write_unlock(&queue->syn_wait_lock); | |
161 | } | |
162 | ||
163 | static inline void reqsk_queue_add(struct request_sock_queue *queue, | |
164 | struct request_sock *req, | |
165 | struct sock *parent, | |
166 | struct sock *child) | |
167 | { | |
168 | req->sk = child; | |
169 | sk_acceptq_added(parent); | |
170 | ||
171 | if (queue->rskq_accept_head == NULL) | |
172 | queue->rskq_accept_head = req; | |
173 | else | |
174 | queue->rskq_accept_tail->dl_next = req; | |
175 | ||
176 | queue->rskq_accept_tail = req; | |
177 | req->dl_next = NULL; | |
178 | } | |
179 | ||
180 | static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue) | |
181 | { | |
182 | struct request_sock *req = queue->rskq_accept_head; | |
183 | ||
184 | BUG_TRAP(req != NULL); | |
185 | ||
186 | queue->rskq_accept_head = req->dl_next; | |
187 | if (queue->rskq_accept_head == NULL) | |
188 | queue->rskq_accept_tail = NULL; | |
189 | ||
190 | return req; | |
191 | } | |
192 | ||
193 | static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue, | |
194 | struct sock *parent) | |
195 | { | |
196 | struct request_sock *req = reqsk_queue_remove(queue); | |
197 | struct sock *child = req->sk; | |
198 | ||
199 | BUG_TRAP(child != NULL); | |
200 | ||
201 | sk_acceptq_removed(parent); | |
202 | __reqsk_free(req); | |
203 | return child; | |
204 | } | |
205 | ||
206 | static inline int reqsk_queue_removed(struct request_sock_queue *queue, | |
207 | struct request_sock *req) | |
208 | { | |
2ad69c55 | 209 | struct listen_sock *lopt = queue->listen_opt; |
0e87506f ACM |
210 | |
211 | if (req->retrans == 0) | |
212 | --lopt->qlen_young; | |
213 | ||
214 | return --lopt->qlen; | |
215 | } | |
216 | ||
217 | static inline int reqsk_queue_added(struct request_sock_queue *queue) | |
218 | { | |
2ad69c55 | 219 | struct listen_sock *lopt = queue->listen_opt; |
0e87506f ACM |
220 | const int prev_qlen = lopt->qlen; |
221 | ||
222 | lopt->qlen_young++; | |
223 | lopt->qlen++; | |
224 | return prev_qlen; | |
225 | } | |
226 | ||
463c84b9 | 227 | static inline int reqsk_queue_len(const struct request_sock_queue *queue) |
0e87506f ACM |
228 | { |
229 | return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0; | |
230 | } | |
231 | ||
463c84b9 | 232 | static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) |
0e87506f ACM |
233 | { |
234 | return queue->listen_opt->qlen_young; | |
235 | } | |
236 | ||
463c84b9 | 237 | static inline int reqsk_queue_is_full(const struct request_sock_queue *queue) |
0e87506f ACM |
238 | { |
239 | return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log; | |
240 | } | |
241 | ||
242 | static inline void reqsk_queue_hash_req(struct request_sock_queue *queue, | |
243 | u32 hash, struct request_sock *req, | |
244 | unsigned timeout) | |
245 | { | |
2ad69c55 | 246 | struct listen_sock *lopt = queue->listen_opt; |
0e87506f ACM |
247 | |
248 | req->expires = jiffies + timeout; | |
249 | req->retrans = 0; | |
250 | req->sk = NULL; | |
251 | req->dl_next = lopt->syn_table[hash]; | |
252 | ||
253 | write_lock(&queue->syn_wait_lock); | |
254 | lopt->syn_table[hash] = req; | |
255 | write_unlock(&queue->syn_wait_lock); | |
256 | } | |
257 | ||
2e6599cb | 258 | #endif /* _REQUEST_SOCK_H */ |