Add nl hashtable structures and access functions

This patch adds the required structures and access functions to create
and manage hashtables for netlink cache objects

Signed-off-by: Shrijeet Mukherjee <shm@cumulusnetworks.com>
Signed-off-by: Nolan Leake <nolan@cumulusnetworks.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Reviewed-by: Wilson Kok <wkok@cumulusnetworks.com>
Signed-off-by: Thomas Graf <tgraf@suug.ch>

diff --git a/include/netlink/hashtable.h b/include/netlink/hashtable.h
new file mode 100644 (file)
index 0000000..d9e6ee4
--- /dev/null
+++ b/include/netlink/hashtable.h
@@ -0,0 +1,52 @@
+/*
+ * netlink/hashtable.h       Netlink hashtable Utilities
+ *
+ *      This library is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU Lesser General Public
+ *      License as published by the Free Software Foundation version 2.1
+ *      of the License.
+ *
+ * Copyright (c) 2012 Cumulus Networks, Inc
+ */
+
+#ifndef NETLINK_HASHTABLE_H_
+#define NETLINK_HASHTABLE_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct nl_hash_node {
+    uint32_t                   key;
+    uint32_t                   key_size;
+    struct nl_object *         obj;
+    struct nl_hash_node *      next;
+} nl_hash_node_t;
+
+typedef struct nl_hash_table {
+    int                        size;
+    nl_hash_node_t **          nodes;
+} nl_hash_table_t;
+
+/* Default hash table size */
+#define NL_MAX_HASH_ENTRIES 1024
+
+/* Access Functions */
+extern nl_hash_table_t *       nl_hash_table_alloc(int size);
+extern void                    nl_hash_table_free(nl_hash_table_t *ht);
+
+extern int                     nl_hash_table_add(nl_hash_table_t *ht,
+                                                 struct nl_object *obj);
+extern int                     nl_hash_table_del(nl_hash_table_t *ht,
+                                                 struct nl_object *obj);
+
+extern struct nl_object *      nl_hash_table_lookup(nl_hash_table_t *ht,
+                                                    struct nl_object *obj);
+extern uint32_t                nl_hash(void *k, size_t length,
+                                       uint32_t initval);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NETLINK_HASHTABLE_H_ */

diff --git a/include/netlink/object-api.h b/include/netlink/object-api.h
index ec2192b5a7230ee6d7ae95e5973f23801f0fda8f..ae6180ac4d1a8c9a6f8089517ad2a5fd6bba1237 100644 (file)
--- a/include/netlink/object-api.h
+++ b/include/netlink/object-api.h
@@ -348,6 +348,16 @@ struct nl_object_ops
         */
        int   (*oo_update)(struct nl_object *, struct nl_object *);
 
+       /**
+        * Hash Key generator function
+        *
+        * When called returns a hash key for the object being
+        * referenced. This key will be used by higher level hash functions
+        * to build association lists. Each object type gets to specify
+        * it's own key formulation
+        */
+       void   (*oo_keygen)(struct nl_object *, uint32_t *, uint32_t);
+
        char *(*oo_attrs2str)(int, char *, size_t);
 
        /**

diff --git a/include/netlink/object.h b/include/netlink/object.h
index 788ae487664e323f3cbf10546408057ff9868f79..f25713ec6220b30371fa910a5045b31ea822834e 100644 (file)
--- a/include/netlink/object.h
+++ b/include/netlink/object.h
@@ -50,6 +50,8 @@ extern char *                 nl_object_attrs2str(struct nl_object *,
                                                    size_t);
 extern char *                  nl_object_attr_list(struct nl_object *,
                                                    char *, size_t);
+extern void                    nl_object_keygen(struct nl_object *,
+                                                uint32_t *, uint32_t);
 
 /* Marks */
 extern void                    nl_object_mark(struct nl_object *);

diff --git a/lib/Makefile.am b/lib/Makefile.am
index c79ba2962f41682ca0c0985e6147cbc519311e95..748194123717f559426bce99f7ea2a8815bde06e 100644 (file)
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -18,7 +18,7 @@ lib_LTLIBRARIES = \
 libnl_3_la_SOURCES = \
        addr.c attr.c cache.c cache_mngr.c cache_mngt.c data.c \
        error.c handlers.c msg.c nl.c object.c socket.c utils.c \
-       version.c hash.c
+       version.c hash.c hashtable.c
 
 libnl_genl_3_la_LIBADD  = libnl-3.la
 libnl_genl_3_la_SOURCES = \

diff --git a/lib/hashtable.c b/lib/hashtable.c
new file mode 100644 (file)
index 0000000..59cd91e
--- /dev/null
+++ b/lib/hashtable.c
@@ -0,0 +1,141 @@
+/*
+ * netlink/hashtable.c      Netlink hashtable Utilities
+ *
+ *      This library is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU Lesser General Public
+ *      License as published by the Free Software Foundation version 2.1
+ *      of the License.
+ *
+ * Copyright (c) 2012 Cumulus Networks, Inc
+ */
+#include <string.h>
+#include <netlink-local.h>
+#include <netlink/object.h>
+#include <netlink/hash.h>
+#include <netlink/hashtable.h>
+
+nl_hash_table_t *nl_hash_table_alloc(int size)
+{
+       nl_hash_table_t *ht;
+
+       ht = calloc(1, sizeof (*ht));
+       if (!ht)
+               goto errout;
+
+       ht->nodes = calloc(size, sizeof (*ht->nodes));
+       if (!ht->nodes) {
+               free(ht);
+               goto errout;
+       }
+
+       ht->size = size;
+
+       return ht;
+errout:
+       return NULL;
+}
+
+void nl_hash_table_free(nl_hash_table_t *ht)
+{
+       int i;
+
+       for(i = 0; i < ht->size; i++) {
+           nl_hash_node_t *node = ht->nodes[i];
+           nl_hash_node_t *saved_node;
+
+           while (node) {
+                  saved_node = node;
+                  node = node->next;
+                  free(saved_node);
+           }
+       }
+
+       free(ht->nodes);
+       free(ht);
+}
+
+struct nl_object* nl_hash_table_lookup(nl_hash_table_t *ht,
+                                      struct nl_object *obj)
+{
+       nl_hash_node_t *node;
+       uint32_t key_hash;
+
+       nl_object_keygen(obj, &key_hash, ht->size);
+       node = ht->nodes[key_hash];
+
+       while (node) {
+              if (nl_object_identical(node->obj, obj))
+                  return node->obj;
+              node = node->next;
+       }
+
+       return NULL;
+}
+
+int nl_hash_table_add(nl_hash_table_t *ht, struct nl_object *obj)
+{
+       nl_hash_node_t *node;
+       uint32_t key_hash;
+
+       nl_object_keygen(obj, &key_hash, ht->size);
+       node = ht->nodes[key_hash];
+
+       while (node) {
+              if (nl_object_identical(node->obj, obj)) {
+                  NL_DBG(2, "Warning: Add to hashtable found duplicate...\n");
+                  return -NLE_EXIST;
+              }
+              node = node->next;
+       }
+
+       NL_DBG (5, "adding cache entry of obj %p in table %p, with hash 0x%x\n",
+               obj, ht, key_hash);
+
+       node = malloc(sizeof(nl_hash_node_t));
+       if (!node)
+               return -NLE_NOMEM;
+       nl_object_get(obj);
+       node->obj = obj;
+       node->key = key_hash;
+       node->key_size = sizeof(uint32_t);
+       node->next = ht->nodes[key_hash];
+       ht->nodes[key_hash] = node;
+
+       return 0;
+}
+
+int nl_hash_table_del(nl_hash_table_t *ht, struct nl_object *obj)
+{
+       nl_hash_node_t *node, *prev;
+       uint32_t key_hash;
+
+       nl_object_keygen(obj, &key_hash, ht->size);
+       prev = node = ht->nodes[key_hash];
+
+       while (node) {
+              if (nl_object_identical(node->obj, obj)) {
+                  nl_object_put(obj);
+
+                  NL_DBG (5, "deleting cache entry of obj %p in table %p, with"
+                          " hash 0x%x\n", obj, ht, key_hash);
+
+                  if (node == ht->nodes[key_hash])
+                      ht->nodes[key_hash] = node->next;
+                  else
+                      prev->next = node->next;
+
+                  free(node);
+
+                  return 0;
+               }
+               prev = node;
+               node = node->next;
+       }
+
+       return -1;
+}
+
+uint32_t nl_hash(void *k, size_t length, uint32_t initval)
+{
+       return(hash(k, length, initval));
+}

diff --git a/lib/object.c b/lib/object.c
index d58f9a73e0e18f288a4fd756ca47ed65fc6b92d8..024062ec09e4f03e9058617f6134b879b201d544 100644 (file)
--- a/lib/object.c
+++ b/lib/object.c
@@ -413,6 +413,27 @@ char *nl_object_attr_list(struct nl_object *obj, char *buf, size_t len)
        return nl_object_attrs2str(obj, obj->ce_mask, buf, len);
 }
 
+/**
+ * Generate object hash key
+ * @arg obj            the object
+ * @arg hashkey                destination buffer to be used for key stream
+ * @arg hashtbl_sz     hash table size
+ *
+ * @return hash key in destination buffer
+ */
+void nl_object_keygen(struct nl_object *obj, uint32_t *hashkey,
+                     uint32_t hashtbl_sz)
+{
+       struct nl_object_ops *ops = obj_ops(obj);
+
+       if (ops->oo_keygen)
+               ops->oo_keygen(obj, hashkey, hashtbl_sz);
+       else
+               *hashkey = 0;
+
+       return;
+}
+
 /** @} */
 
 /**