Traffic monitoring device, and traffic monitoring method

1. A traffic monitoring apparatus comprising:

a processor;

a memory storing a program to be executed by the processor, the program including instructions to:

acquire one or more identifiers from a header of a received packet;

convert a rule table into a predetermined format and register the rule table, wherein the rule table includes rules in which one or more rule elements are registered for each of the rules; and

search for matching rules from the rule table to be matched with the one or more identifiers;

wherein the instructions to search for matching rules includes instructions to:

output values indicating the matching rules to be matched with the one or more identifiers; and

calculate a logical AND of the output values indicating the matching rules to be matched with the one or more identifiers; and

wherein the instructions to output values indicating the matching rules to be matched with the one or more identifiers includes instructions to:

calculate hash values of the one or more identifiers;

hold, in a hash table, values representing rules to be matched with identifiers for hash values identifying each of the rule elements;

hold, in a wild card storage circuit, values representing wild card rules for which wild cards have been set, for each of the rule elements; and

calculate a logical OR of values in the hash table corresponding to the hash values of the rule elements and corresponding values of corresponding rule elements in the wild card storage circuit.

2. The traffic monitoring apparatus according to claim 1 , wherein the hash table is configured with:

a first table in which an address of a second table is registered for each of the hash values of the rule elements; and

the second table in which the values representing the rules to be matched with the one or more identifiers are registered for each address.

3. The traffic monitoring apparatus according to claim 1 , wherein instructions to search for matching rules includes further instructions to:

calculate hash values for the rule elements;

group rule elements of the rule elements with a same hash value for each of the rule elements;

calculate values representing the rules to be matched with the one or more identifiers for each group of the rule elements;

calculate values representing the rules for which the wild cards have been set, for each of the rule elements; and

register the calculated values in the hash table and the wild card storage circuit.

4. The traffic monitoring apparatus according to claim 1 , wherein the hash table holds, for each of the hash values of the rule elements, a bit sequence in which rules with described identifiers corresponding to the hash values of the rule elements are represented by 1 and other rules are represented by 0, and wherein the wild card storage circuit holds, for each of the rule elements, a bit sequence in which rules with wild cards set are represented by 1 and other rules are represented by 0.

5. A traffic monitoring method comprising:

converting a rule table into a predetermined format and registering the rule table, wherein the rule table includes rules in which one or more rule elements are registered for each of the rules

acquiring one or more identifiers from a header of a received packet; and

searching for matching rules to be matched with the one or more identifiers;

wherein the searching for the matching rules includes:

a step of outputting values representing the matching rules to be matched with the one or more identifiers, the step of outputting the values including:

calculating hash values of the one or more identifiers;

searching for a hash table that holds values representing rules to be matched with identifiers for hash values identifying each of the rule elements, using the hash values of the one or more identifiers as inputs; and

calculating, for each of the rule elements, a logical OR of wild card information constituted by a value output from the hash table and a value representing a rule for which a wild card has been set in a corresponding one of the rule elements; and

a step of calculating a logical AND of the logical OR calculated for each of the rule elements.

6. The traffic monitoring method according to claim 5 , wherein the hash table is configured with:

a first table in which an address of a second table is registered for each of the hash values of the rule elements; and

the second table in which the values representing the rules to be matched with the one or more identifiers are registered for each address.

7. The traffic monitoring method according to claim 5 , wherein the registering of the rule table includes:

calculating hash values for the rule elements;

grouping rule elements of the rule elements with a same hash value for each of the rule elements;

calculating values representing the rules to be matched with the identifiers for each group of the rule elements;

calculating values representing the rules for which the wild cards have been set, for each of the rule elements; and

registering the calculated values in the hash table and the wild card information.

8. The traffic monitoring method according to claim 5 , wherein the hash table holds, for each of the hash values, a bit sequence in which rules with described identifiers corresponding to the hash values are represented by 1 and other rules are represented by 0, and the wild card information is a bit sequence in which for each of the rule elements, a bit sequence in which rules with wild cards set are represented by 1 and other rules are represented by 0.