lib/qobj.c

   1 /*
   2  * Copyright (c) 2015-16  David Lamparter, for NetDEF, Inc.
   3  *
   4  * This file is part of Quagga
   5  *
   6  * Quagga is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2, or (at your option) any
   9  * later version.
  10  *
  11  * Quagga is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <zebra.h>
  22
  23 #include "thread.h"
  24 #include "memory.h"
  25 #include "hash.h"
  26 #include "log.h"
  27 #include "qobj.h"
  28 #include "jhash.h"
  29
  30 static uint32_t qobj_hash(const struct qobj_node *node)
  31 {
  32         return (uint32_t)node->nid;
  33 }
  34
  35 static int qobj_cmp(const struct qobj_node *na, const struct qobj_node *nb)
  36 {
  37         if (na->nid < nb->nid)
  38                 return -1;
  39         if (na->nid > nb->nid)
  40                 return 1;
  41         return 0;
  42 }
  43
  44 DECLARE_HASH(qobj_nodes, struct qobj_node, nodehash,
  45                         qobj_cmp, qobj_hash)
  46
  47 static pthread_rwlock_t nodes_lock;
  48 static struct qobj_nodes_head nodes = { };
  49
  50
  51 void qobj_reg(struct qobj_node *node, const struct qobj_nodetype *type)
  52 {
  53         node->type = type;
  54         pthread_rwlock_wrlock(&nodes_lock);
  55         do {
  56                 node->nid = (uint64_t)random();
  57                 node->nid ^= (uint64_t)random() << 32;
  58         } while (!node->nid || qobj_nodes_find(&nodes, node));
  59         qobj_nodes_add(&nodes, node);
  60         pthread_rwlock_unlock(&nodes_lock);
  61 }
  62
  63 void qobj_unreg(struct qobj_node *node)
  64 {
  65         pthread_rwlock_wrlock(&nodes_lock);
  66         qobj_nodes_del(&nodes, node);
  67         pthread_rwlock_unlock(&nodes_lock);
  68 }
  69
  70 struct qobj_node *qobj_get(uint64_t id)
  71 {
  72         struct qobj_node dummy = {.nid = id}, *rv;
  73         pthread_rwlock_rdlock(&nodes_lock);
  74         rv = qobj_nodes_find(&nodes, &dummy);
  75         pthread_rwlock_unlock(&nodes_lock);
  76         return rv;
  77 }
  78
  79 void *qobj_get_typed(uint64_t id, const struct qobj_nodetype *type)
  80 {
  81         struct qobj_node dummy = {.nid = id};
  82         struct qobj_node *node;
  83         void *rv;
  84
  85         pthread_rwlock_rdlock(&nodes_lock);
  86         node = qobj_nodes_find(&nodes, &dummy);
  87
  88         /* note: we explicitly hold the lock until after we have checked the
  89          * type.
  90          * if the caller holds a lock that for example prevents the deletion of
  91          * route-maps, we can still race against a delete of something that
  92          * isn't
  93          * a route-map. */
  94         if (!node || node->type != type)
  95                 rv = NULL;
  96         else
  97                 rv = (char *)node - node->type->node_member_offset;
  98
  99         pthread_rwlock_unlock(&nodes_lock);
 100         return rv;
 101 }
 102
 103 void qobj_init(void)
 104 {
 105         pthread_rwlock_init(&nodes_lock, NULL);
 106         qobj_nodes_init(&nodes);
 107 }
 108
 109 void qobj_finish(void)
 110 {
 111         struct qobj_node *node;
 112         while ((node = qobj_nodes_pop(&nodes)))
 113                 qobj_nodes_del(&nodes, node);
 114         pthread_rwlock_destroy(&nodes_lock);
 115 }