Added IPv4Reassembler class.

include/ip.h

@@ -568,6 +568,13 @@ namespace Tins {
          */
         PDU *recv_response(PacketSender &sender, const NetworkInterface &);
 
+        /**
+         * Indicates whether this PDU is fragmented.
+         *
+         * \return true if this PDU is fragmented, false otherwise.
+         */
+        bool is_fragmented() const;
+
         /**
          * \brief Getter for the PDU's type.
          * \sa PDU::pdu_type

include/ip_reassembler.h

@@ -0,0 +1,216 @@
+/*
+ * Copyright (c) 2012, Matias Fontanini
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following disclaimer
+ *   in the documentation and/or other materials provided with the
+ *   distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef TINS_IP_REASSEMBLER_H
+#define TINS_IP_REASSEMBLER_H
+
+#include <vector>
+#include <map>
+#include "pdu.h"
+#include "ip_address.h"
+
+namespace Tins {
+/** 
+ * \cond
+ */
+class IP;
+namespace Internals {
+class IPv4Fragment {
+public:
+    typedef PDU::serialization_type payload_type;
+
+    IPv4Fragment() : offset_() { }
+
+    template<typename T>
+    IPv4Fragment(T *pdu, uint16_t offset)
+    : payload_(pdu->serialize()), offset_(offset) 
+    {
+        
+    }
+    
+    const payload_type &payload() const {
+        return payload_;
+    }
+    
+    uint16_t offset() const {
+        return offset_;
+    }
+private:
+    payload_type payload_;
+    uint16_t offset_;
+};
+
+class IPv4Stream {
+public:
+    IPv4Stream();
+    
+    void add_fragment(IP *ip);
+    bool is_complete() const;
+    PDU *allocate_pdu() const;
+private:
+    typedef std::vector<IPv4Fragment> fragments_type;
+    
+    uint16_t extract_offset(const IP *ip);
+    bool extract_more_frag(const IP *ip);
+
+    fragments_type fragments;
+    bool received_end;
+    uint8_t transport_proto;
+    size_t received_size, total_size;
+};
+} // namespace Internals
+
+/** 
+ * \endcond
+ */
+
+/**
+ * \brief Reassembles fragmented IP packets.
+ */
+class IPv4Reassembler {
+public:
+    /**
+     * The status of each processed packet.
+     */
+    enum packet_status {
+        NOT_FRAGMENTED,
+        FRAGMENTED,
+        REASSEMBLED
+    };
+
+    /**
+     * The type used to represent the overlapped segment 
+     * reassembly technique to be used.
+     */
+    enum overlapping_technique {
+        NONE
+    };
+
+    /**
+     * Constructs an IPV4Reassembler.
+     * \param technique The technique to be used for reassembling
+     * overlapped fragments.
+     */
+    IPv4Reassembler(overlapping_technique technique = NONE);
+
+    /**
+     * \brief Processes a PDU and tries to reassemble it.
+     *
+     * This method tries to reassemble the provided packet. If
+     * the packet is successfully reassembled using previously
+     * processed packets, its contents will be modified so that
+     * it contains the whole payload and not just a fragment.
+     * 
+     * \param pdu The PDU to process.
+     * \return NOT_FRAGMENTED if the PDU does not contain an IP
+     * layer or is not fragmented, FRAGMENTED if the packet is 
+     * fragmented or REASSEMBLED if the packet was fragmented 
+     * but has now been reassembled.
+     */
+    packet_status process(PDU &pdu);
+
+    /**
+     * Removes all of the packets and data stored.
+     */
+    void clear_streams();
+
+    /**
+     * \brief Removes all of the packets and data stored that 
+     * belongs to IP headers whose identifier, source and destination
+     * addresses are equal to the provided parameters.
+     * 
+     * \param id The idenfier to search.
+     * \param addr1 The source address to search.
+     * \param addr2 The destinatin address to search.
+     * \sa IP::id
+     */
+    void remove_stream(uint16_t id, IPv4Address addr1, IPv4Address addr2);
+private:
+    typedef std::pair<IPv4Address, IPv4Address> address_pair;
+    typedef std::pair<uint16_t, address_pair> key_type;
+    typedef std::map<key_type, Internals::IPv4Stream> streams_type;
+
+    key_type make_key(const IP *ip) const;
+    address_pair make_address_pair(IPv4Address addr1, IPv4Address addr2) const;
+    
+    streams_type streams;
+    overlapping_technique technique;
+};
+
+/**
+ * Proxy functor class that reassembles PDUs.
+ */
+template<typename Functor>
+class IPv4ReassemblerProxy {
+public:
+    /**
+     * Constructs the proxy from a functor object.
+     *
+     * \param func The functor object.
+     */
+    IPv4ReassemblerProxy(Functor func)
+    : functor_(func)
+    {
+
+    }
+
+    /**
+     * \brief Tries to reassemble the packet and forwards it to 
+     * the functor.
+     * 
+     * \param pdu The packet to process
+     * \return true if the packet wasn't forwarded, otherwise
+     * the value returned by the functor.
+     */
+    bool operator()(PDU &pdu) {
+        // Forward it unless it's fragmented.
+        if(reassembler.process(pdu) != IPv4Reassembler::FRAGMENTED)
+            return functor_(pdu);
+        else
+            return true;
+    }
+private:
+    IPv4Reassembler reassembler;
+    Functor functor_;
+};
+
+/**
+ * Helper function that creates an IPv4ReassemblerProxy.
+ *
+ * \param func The functor object to use in the IPv4ReassemblerProxy.
+ * \return An IPv4ReassemblerProxy.
+ */
+template<typename Functor>
+IPv4ReassemblerProxy<Functor> make_ipv4_reassembler_proxy(Functor func) {
+    return IPv4ReassemblerProxy<Functor>(func);
+}
+}
+
+
+#endif // TINS_IP_REASSEMBLER_H

include/tins.h

@@ -70,5 +70,7 @@
 #include "handshake_capturer.h"
 #include "address_range.h"
 #include "pdu_allocator.h"
+#include "ipsec.h"
+#include "ip_reassembler.h"
 
 #endif // TINS_TINS_H