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 #include "network.h"
  30
  31 static uint32_t qobj_hash(const struct qobj_node *node)
  32 {
  33         return (uint32_t)node->nid;
  34 }
  35
  36 static int qobj_cmp(const struct qobj_node *na, const struct qobj_node *nb)
  37 {
  38         if (na->nid < nb->nid)
  39                 return -1;
  40         if (na->nid > nb->nid)
  41                 return 1;
  42         return 0;
  43 }
  44
  45 DECLARE_HASH(qobj_nodes, struct qobj_node, nodehash,
  46                         qobj_cmp, qobj_hash)
  47
  48 static pthread_rwlock_t nodes_lock;
  49 static struct qobj_nodes_head nodes = { };
  50
  51
  52 void qobj_reg(struct qobj_node *node, const struct qobj_nodetype *type)
  53 {
  54         node->type = type;
  55         pthread_rwlock_wrlock(&nodes_lock);
  56         do {
  57                 node->nid = (uint64_t)frr_weak_random();
  58                 node->nid ^= (uint64_t)frr_weak_random() << 32;
  59         } while (!node->nid || qobj_nodes_find(&nodes, node));
  60         qobj_nodes_add(&nodes, node);
  61         pthread_rwlock_unlock(&nodes_lock);
  62 }
  63
  64 void qobj_unreg(struct qobj_node *node)
  65 {
  66         pthread_rwlock_wrlock(&nodes_lock);
  67         qobj_nodes_del(&nodes, node);
  68         pthread_rwlock_unlock(&nodes_lock);
  69 }
  70
  71 struct qobj_node *qobj_get(uint64_t id)
  72 {
  73         struct qobj_node dummy = {.nid = id}, *rv;
  74         pthread_rwlock_rdlock(&nodes_lock);
  75         rv = qobj_nodes_find(&nodes, &dummy);
  76         pthread_rwlock_unlock(&nodes_lock);
  77         return rv;
  78 }
  79
  80 void *qobj_get_typed(uint64_t id, const struct qobj_nodetype *type)
  81 {
  82         struct qobj_node dummy = {.nid = id};
  83         struct qobj_node *node;
  84         void *rv;
  85
  86         pthread_rwlock_rdlock(&nodes_lock);
  87         node = qobj_nodes_find(&nodes, &dummy);
  88
  89         /* note: we explicitly hold the lock until after we have checked the
  90          * type.
  91          * if the caller holds a lock that for example prevents the deletion of
  92          * route-maps, we can still race against a delete of something that
  93          * isn't
  94          * a route-map. */
  95         if (!node || node->type != type)
  96                 rv = NULL;
  97         else
  98                 rv = (char *)node - node->type->node_member_offset;
  99
 100         pthread_rwlock_unlock(&nodes_lock);
 101         return rv;
 102 }
 103
 104 void qobj_init(void)
 105 {
 106         pthread_rwlock_init(&nodes_lock, NULL);
 107         qobj_nodes_init(&nodes);
 108 }
 109
 110 void qobj_finish(void)
 111 {
 112         struct qobj_node *node;
 113         while ((node = qobj_nodes_pop(&nodes)))
 114                 qobj_nodes_del(&nodes, node);
 115         pthread_rwlock_destroy(&nodes_lock);
 116 }