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1 | package Guardian::Events; | |
2 | use strict; | |
3 | use warnings; | |
4 | ||
5 | use Exporter qw(import); | |
6 | ||
7 | our @EXPORT_OK = qw(Init CheckAction Update); | |
8 | ||
9 | # Hash which stores all supported commands from the queue. | |
10 | my %commands = ( | |
11 | 'count' => \&Counter, | |
12 | 'block' => \&CallBlock, | |
13 | 'unblock' => \&CallUnblock, | |
14 | 'flush' => \&CallFlush, | |
15 | ); | |
16 | ||
17 | # Hash to store addresses and their current count. | |
18 | my %counthash = (); | |
19 | ||
20 | # Hash to store all currentyl blocked addresses and a timestamp | |
21 | # when the block for this address can be released. | |
22 | my %blockhash = (); | |
23 | ||
24 | # This object will contain the reference to the logger object after calling Init. | |
25 | my $logger; | |
26 | ||
27 | # | |
28 | ## The "Init" (Block) function. | |
29 | # | |
30 | ## This function is responsible to initialize Block as a class based object. | |
31 | ## It has to be called once before any blocking event can be processed. | |
32 | # | |
33 | ## The following arguments must be passed, during initialization: | |
34 | ## "BlockCount" and "BlockTime" which both have to be natural numbers. | |
35 | # | |
36 | sub Init (%) { | |
37 | my ( $class, %args ) = @_; | |
38 | my $self = \%args; | |
39 | ||
40 | # Fail, if some critical arguments are missing. | |
41 | unless ((exists($self->{BlockCount})) && (exists($self->{BlockTime}))) { | |
42 | die "Could not initialize Block: Too less arguments are given.\n"; | |
43 | } | |
44 | ||
45 | # Use bless to make "$self" to an object of class "$class". | |
46 | bless($self, $class); | |
47 | ||
48 | # Assign logger object. | |
49 | $logger = $self->{Logger}; | |
50 | ||
51 | # Log used firewall engine. | |
52 | $logger->Log("debug", "Using firewall engine: $self->{FirewallEngine}"); | |
53 | ||
54 | # Try to load the specified firewall engine or die. | |
55 | my $module_name = "Guardian::" . $self->{FirewallEngine}; | |
56 | eval "use $module_name; 1" or die "Could not load a module for firewall engine: $self->{FirewallEngine}!"; | |
57 | ||
58 | # Return the class object. | |
59 | return $self; | |
60 | } | |
61 | ||
62 | # | |
63 | ## The main "CheckAction" function. | |
64 | # | |
65 | ## This function is used to handle each recived event from the main event queue of guardian. | |
66 | # | |
67 | ## It will check if the given command is valid and will pass it to the responsible function. | |
68 | # | |
69 | sub CheckAction ($$) { | |
70 | my $self = shift; | |
71 | my @event = split(/ /, $_[0], 4); | |
72 | my ($command, $address, $module, $message) = @event; | |
73 | ||
74 | # Check if we got an invalid command. | |
75 | unless(exists($commands{$command})) { | |
76 | $logger->Log("err", "The CheckAction function has been called with an unsupported command ($command)!"); | |
77 | return; | |
78 | } | |
79 | ||
80 | # Check if the given address is valid. | |
81 | unless(&Guardian::Base::IsValidAddressOrNetwork($address)) { | |
82 | # Log error message. | |
83 | $logger->Log("err", "Invalid IP address: $address"); | |
84 | return; | |
85 | } | |
86 | ||
87 | # Call required handler. | |
88 | my $error = $commands{$command}->($self, $address, $module, $message); | |
89 | ||
90 | # If we got any return code, something went wrong and should be logged. | |
91 | if ($error) { | |
92 | $logger->Log("err", "Got error: $error"); | |
93 | return; | |
94 | } | |
95 | } | |
96 | ||
97 | # | |
98 | ## The main "Counter" function. | |
99 | # | |
100 | ## This function is used to handle each count message + address, which has been sent by the main event | |
101 | ## loop of guardian. | |
102 | # | |
103 | ## It stores the address and the current count into the counthash and increase the count each time when | |
104 | ## the same address should be counted again. When the current count reaches the configured BlockCount, | |
105 | ## the responsible function will be called to block the address. | |
106 | # | |
107 | sub Counter ($@) { | |
108 | my $self = shift; | |
109 | my ($address, $module, $message) = @_; | |
110 | ||
111 | # Log event. | |
112 | $logger->Log("debug", "$module reported $message for address: $address"); | |
113 | ||
114 | # Increase existing count or start counting for new source addresses. | |
115 | if (exists($counthash{$address})) { | |
116 | # Skip already blocked addresses. | |
117 | if (exists($blockhash{$address})) { | |
118 | return undef; | |
119 | } | |
120 | ||
121 | # Increase count of the existing entry. | |
122 | $counthash{$address} = $counthash{$address} + 1; | |
123 | ||
124 | # Log altered count of the address. | |
125 | $logger->Log("debug", "Source $address now has count $counthash{$address}/$self->{BlockCount}..."); | |
126 | } else { | |
127 | # Log that counting for the address has been started. | |
128 | $logger->Log("debug", "Start counting for $address..."); | |
129 | ||
130 | # Set count to "1". | |
131 | $counthash{$address} = 1; | |
132 | } | |
133 | ||
134 | # Check if the address has reached the configured count limit. | |
135 | if ($counthash{$address} >= $self->{BlockCount}) { | |
136 | # Write out log message. | |
137 | $logger->Log("info", "Blocking $address for $self->{BlockTime} seconds..."); | |
138 | ||
139 | # Call block subroutine to block the address. | |
140 | my $error = &CallBlock($self, $address, $module, $message); | |
141 | ||
142 | # Return the message if an error occurs. | |
143 | return $error; | |
144 | } | |
145 | ||
146 | # Everything worked well, return nothing. | |
147 | return undef; | |
148 | } | |
149 | ||
150 | # | |
151 | ## The RemoveBlocks function. | |
152 | # | |
153 | ## This function periodly will be called and is responsible for releasing the block if the Blocktime | |
154 | ## on an address has expired. | |
155 | # | |
156 | ## To do this, the code will loop through all entries of the blockhash and check | |
157 | ## if the estimiated BlockTime of each address has reached and so the block can be released. | |
158 | # | |
159 | sub RemoveBlocks () { | |
160 | my $self = shift; | |
161 | ||
162 | # Get the current time. | |
163 | my $time = time(); | |
164 | ||
165 | # Loop through the blockhash. | |
166 | foreach my $address (keys %blockhash) { | |
167 | # Check if the blocktime for the address has expired. | |
168 | if ($blockhash{$address} <= $time) { | |
169 | # Call unblock subroutine. | |
170 | my $error = &CallUnblock($self, $address, "BlockTime", "has expired for $address"); | |
171 | ||
172 | # Log error messages if returned. | |
173 | if ($error) { | |
174 | $logger->Log("err", "$error"); | |
175 | } | |
176 | } | |
177 | } | |
178 | ||
179 | # Everything okay, return nothing. | |
180 | return undef; | |
181 | } | |
182 | ||
183 | # | |
184 | ## The CallBlock function. | |
185 | # | |
186 | ## This function is called, if the BlockCount for an address is reached or a direct | |
187 | ## request for blocking an address has been recieved. | |
188 | # | |
189 | sub CallBlock ($@) { | |
190 | my $self = shift; | |
191 | my ($address, $module, $message) = @_; | |
192 | ||
193 | # Log the call for blocking an address. | |
194 | $logger->Log("info", "$module - $message"); | |
195 | ||
196 | # Check if an entry for this address exists | |
197 | # in the blockhash. If not, the address has | |
198 | # not been blocked yet, call the responisible | |
199 | # function to do this now. | |
200 | unless (exists($blockhash{$address})) { | |
201 | # Obtain the configured FirewallAction. | |
202 | my $action = $self->{FirewallAction}; | |
203 | ||
204 | # Block the given address. | |
205 | my $error = &DoBlock($address, $action); | |
206 | ||
207 | # If we got back an error message something went wrong. | |
208 | if ($error) { | |
209 | # Exit function and return the used FirewallEngine and the error message. | |
210 | return "$self->{FirewallEngine} - $error"; | |
211 | } else { | |
212 | # Address has been successfully blocked, print a log message. | |
213 | $logger->Log("debug", "Address $address successfully has been blocked..."); | |
214 | } | |
215 | } | |
216 | ||
217 | # Generate time when the block will expire. | |
218 | my $expire = time() + $self->{BlockTime}; | |
219 | ||
220 | # Store the blocked address and the expire time | |
221 | # in the blockhash. | |
222 | $blockhash{$address} = $expire; | |
223 | ||
224 | # Return nothing "undef" if everything is okay. | |
225 | return undef; | |
226 | } | |
227 | ||
228 | # | |
229 | ## CallUnblock function. | |
230 | # | |
231 | ## This function is responsible for unblocking and deleting a given | |
232 | ## address from the blockhash. | |
233 | # | |
234 | sub CallUnblock ($) { | |
235 | my $self = shift; | |
236 | my ($address, $module, $message) = @_; | |
237 | ||
238 | # Log the call for unblocking an address. | |
239 | $logger->Log("info", "$module - $message"); | |
240 | ||
241 | # Return an error if no entry for the given address | |
242 | # is present in the blockhash. | |
243 | unless (exists($blockhash{$address})) { | |
244 | return "Address $address was not blocked!"; | |
245 | } | |
246 | ||
247 | # Unblock the address. | |
248 | my $error = &DoUnblock($address); | |
249 | ||
250 | # If an error message is returned, something went wrong. | |
251 | if ($error) { | |
252 | # Exit function and return the error message. | |
253 | return $error; | |
254 | } else { | |
255 | # Address successfully has been unblocked. | |
256 | $logger->Log("debug", "Address $address successfully has been unblocked..."); | |
257 | } | |
258 | ||
259 | # Drop address from blockhash. | |
260 | delete ($blockhash{$address}); | |
261 | ||
262 | # Everything worked well, return nothing. | |
263 | return undef; | |
264 | } | |
265 | ||
266 | 1; |