LCOV - code coverage report
Current view: top level - include/net - request_sock.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 1 1 100.0 %
Date: 2017-01-25 Functions: 0 0 -

          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             : 
      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             : 
     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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