csum: Avoid misaligned data access.

[openvswitch] / lib / classifier.c

diff --git a/lib/classifier.c b/lib/classifier.c
index 6be47f8af110467e02aab44e1e455e102203080c..591322e7748fc5598c2ae82ab882b2b5fe0d3cba 100644 (file)
--- a/lib/classifier.c
+++ b/lib/classifier.c
@@ -423,7 +423,7 @@ classifier_remove(struct classifier *cls, struct cls_rule *rule)
         hmap_replace(&table->rules, &rule->hmap_node, &next->hmap_node);
     }
 
-    if (--table->n_table_rules == 0 && !table->n_refs) {
+    if (--table->n_table_rules == 0) {
         destroy_table(cls, table);
     }
 
@@ -507,10 +507,34 @@ classifier_rule_overlaps(const struct classifier *cls,
 
     return false;
 }
+\f
+/* Iteration. */
+
+static bool
+rule_matches(const struct cls_rule *rule, const struct cls_rule *target)
+{
+    return (!target
+            || flow_equal_except(&rule->flow, &target->flow, &target->wc));
+}
+
+static struct cls_rule *
+search_table(const struct cls_table *table, const struct cls_rule *target)
+{
+    if (!target || !flow_wildcards_has_extra(&table->wc, &target->wc)) {
+        struct cls_rule *rule;
+
+        HMAP_FOR_EACH (rule, hmap_node, &table->rules) {
+            if (rule_matches(rule, target)) {
+                return rule;
+            }
+        }
+    }
+    return NULL;
+}
 
-/* Searches 'cls' for rules that exactly match 'target' or are more specific
- * than 'target'.  That is, a given 'rule' matches 'target' if, for every
- * field:
+/* Initializes 'cursor' for iterating through 'cls' rules that exactly match
+ * 'target' or are more specific than 'target'.  That is, a given 'rule'
+ * matches 'target' if, for every field:
  *
  *   - 'target' and 'rule' specify the same (non-wildcarded) value for the
  *     field, or
@@ -541,72 +565,63 @@ classifier_rule_overlaps(const struct classifier *cls,
  *
  * Ignores target->priority.
  *
- * 'callback' is allowed to delete the rule that is passed as its argument, but
- * it must not delete (or move) any other rules in 'cls' that have the same
- * wildcards as the argument rule. */
+ * 'target' may be NULL to iterate over every rule in 'cls'. */
 void
-classifier_for_each_match(const struct classifier *cls_,
-                          const struct cls_rule *target,
-                          cls_cb_func *callback, void *aux)
-{
-    struct classifier *cls = (struct classifier *) cls_;
-    struct cls_table *table, *next_table;
-
-    for (table = classifier_first_table(cls); table; table = next_table) {
-        if (!flow_wildcards_has_extra(&table->wc, &target->wc)) {
-            /* We have eliminated the "no" case in the truth table above.  Two
-             * of the three remaining cases are trivial.  We only need to check
-             * the fourth case, where both 'rule' and 'target' require an exact
-             * match. */
-            struct cls_rule *head, *next_head;
-
-            table->n_refs++;
-            HMAP_FOR_EACH_SAFE (head, next_head, hmap_node, &table->rules) {
-                if (flow_equal_except(&head->flow, &target->flow,
-                                      &target->wc)) {
-                    struct cls_rule *rule, *next_rule;
-
-                    FOR_EACH_RULE_IN_LIST_SAFE (rule, next_rule, head) {
-                        callback(rule, aux);
-                    }
-                }
-            }
-            next_table = classifier_next_table(cls, table);
-            if (!--table->n_refs && !table->n_table_rules) {
-                destroy_table(cls, table);
-            }
-        } else {
-            next_table = classifier_next_table(cls, table);
+cls_cursor_init(struct cls_cursor *cursor, const struct classifier *cls,
+                const struct cls_rule *target)
+{
+    cursor->cls = cls;
+    cursor->target = target;
+}
+
+/* Returns the first matching cls_rule in 'cursor''s iteration, or a null
+ * pointer if there are no matches. */
+struct cls_rule *
+cls_cursor_first(struct cls_cursor *cursor)
+{
+    struct cls_table *table;
+
+    for (table = classifier_first_table(cursor->cls); table;
+         table = classifier_next_table(cursor->cls, table)) {
+        struct cls_rule *rule = search_table(table, cursor->target);
+        if (rule) {
+            cursor->table = table;
+            return rule;
         }
     }
+
+    return NULL;
 }
 
-/* 'callback' is allowed to delete the rule that is passed as its argument, but
- * it must not delete (or move) any other rules in 'cls' that have the same
- * wildcards as the argument rule. */
-void
-classifier_for_each(const struct classifier *cls_,
-                    cls_cb_func *callback, void *aux)
+/* Returns the next matching cls_rule in 'cursor''s iteration, or a null
+ * pointer if there are no more matches. */
+struct cls_rule *
+cls_cursor_next(struct cls_cursor *cursor, struct cls_rule *rule)
 {
-    struct classifier *cls = (struct classifier *) cls_;
-    struct cls_table *table, *next_table;
-
-    for (table = classifier_first_table(cls); table; table = next_table) {
-        struct cls_rule *head, *next_head;
+    const struct cls_table *table;
+    struct cls_rule *next;
 
-        table->n_refs++;
-        HMAP_FOR_EACH_SAFE (head, next_head, hmap_node, &table->rules) {
-            struct cls_rule *rule, *next_rule;
+    next = next_rule_in_list(rule);
+    if (next) {
+        return next;
+    }
 
-            FOR_EACH_RULE_IN_LIST_SAFE (rule, next_rule, head) {
-                callback(rule, aux);
-            }
+    HMAP_FOR_EACH_CONTINUE (rule, hmap_node, &cursor->table->rules) {
+        if (rule_matches(rule, cursor->target)) {
+            return rule;
         }
-        next_table = classifier_next_table(cls, table);
-        if (!--table->n_refs && !table->n_table_rules) {
-            destroy_table(cls, table);
+    }
+
+    for (table = classifier_next_table(cursor->cls, cursor->table); table;
+         table = classifier_next_table(cursor->cls, table)) {
+        rule = search_table(table, cursor->target);
+        if (rule) {
+            cursor->table = table;
+            return rule;
         }
     }
+
+    return NULL;
 }
 \f
 static struct cls_table *