request_sock.h 6.7 KB

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