simnet
Class SimpleFilter

java.lang.Object
  simnet.IPFilter
      simnet.SimpleFilter

All Implemented Interfaces:

Pluggable

public class SimpleFilter

extends IPFilter

implements Pluggable

A simple implementation of a set of rules and BPF filters. Rules are run in order by number until a match is found, and the allow/deny of that rule determines action. For packets that are allowed, all BPFs are run on them.

Field Summary

Vektor	bpfs The Vector that holds this Filter' s BPF rules
private java.util.Hashtable	removeHash
java.util.TreeSet	rules This Filer' s rule list

Fields inherited from class simnet.IPFilter

id

Constructor Summary

SimpleFilter()

Method Summary

void	addBPF(BPF bpf) Adds the specified BPF rule to the BPF table.
void	addRule(int rule_id, int action, int protocol, int src_id, int dest_id, int dest_port) Adds a rule with the specified fields to this Filter's rule list.
void	addRule(Rule rule) Adds the specified rule to this Filter' s rule list.
boolean	in(IP_Packet ipp) Processes incoming IP packets by checking them against each Rule in increasing order of their IDs.
void	initialize(int filter_id) Initializes a new SimpleFilter by initializing its ID and default rules.
boolean	prePlugout(java.lang.Object replacement) No special cleanup is needed.
void	removeBPF(BPF bpf) Removes the specified BPF rule from the BPF table.
void	removeRule(int rid) Removes the Rule with the specified ID from the rule list.
java.lang.String	toString() Returns a String listinag all of this Filter's Rules.

Methods inherited from class simnet.IPFilter

finalize

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

rules

public java.util.TreeSet rules

This Filer' s rule list

bpfs

public Vektor bpfs

The Vector that holds this Filter' s BPF rules

removeHash

private java.util.Hashtable removeHash

Constructor Detail

SimpleFilter

public SimpleFilter()

Method Detail

initialize

public void initialize(int filter_id)

Initializes a new SimpleFilter by initializing its ID and default rules.

Specified by:

initialize in class IPFilter

Parameters:

filter_id - the ID of this filter

in

public boolean in(IP_Packet ipp)

Processes incoming IP packets by checking them against each Rule in increasing order of their IDs. The action determined by the first rule that matches the packet is taken.

Specified by:

in in class IPFilter

Parameters:

ipp - the incoming IP packet

Returns:

TRUE if the packet matches a rule with an ALLOW action; FALSE if it matches a packet with a DENY action or if it does not match any rule at all

addRule

public void addRule(Rule rule)

Adds the specified rule to this Filter' s rule list.

Specified by:

addRule in class IPFilter

Parameters:

rule - the rule to add

addRule

public void addRule(int rule_id,
                    int action,
                    int protocol,
                    int src_id,
                    int dest_id,
                    int dest_port)

Adds a rule with the specified fields to this Filter's rule list.

Specified by:

addRule in class IPFilter

Parameters:

rule_id - the unique ID of this Rule

action - the action to take when a packet has been matched (either Simnet.ALLOW or Simnet.DENY)

protocol - the Rule' s protocol

src_id - the Rule' s source Node

dest_id - the Rule's destination Node

dest_port - the Rule' s destination port

removeRule

public void removeRule(int rid)

Removes the Rule with the specified ID from the rule list. Note: the TreeSet.remove() method only takes objects, so in order to delete an object from the Tree, we need to keep a pointer to that object. However all we have is the ID, so we keep track of the objects and their IDs in a hashtable. This isn' t very elegant but it works.

Specified by:

removeRule in class IPFilter

Parameters:

rid - The Rule's ID

addBPF

public void addBPF(BPF bpf)

Adds the specified BPF rule to the BPF table.

Specified by:

addBPF in class IPFilter

Parameters:

bpf - the BPF rule to add

removeBPF

public void removeBPF(BPF bpf)

Removes the specified BPF rule from the BPF table.

Specified by:

removeBPF in class IPFilter

Parameters:

bpf - the BPF rule to remove

toString

public java.lang.String toString()

Returns a String listinag all of this Filter's Rules.

prePlugout

public boolean prePlugout(java.lang.Object replacement)

No special cleanup is needed.

Specified by:

prePlugout in interface Pluggable

Returns:

if this object can now be removed (was the operation sucessful)