Tins::IPv4Reassembler Class Reference

Reassembles fragmented IP packets. More...

#include <ip_reassembler.h>

Public Types
enum	PacketStatus { NOT_FRAGMENTED, FRAGMENTED, REASSEMBLED }
enum	OverlappingTechnique { NONE }

Public Member Functions
	TINS_DEPRECATED (typedef PacketStatus packet_status)
	IPv4Reassembler ()
	IPv4Reassembler (OverlappingTechnique technique)
PacketStatus	process (PDU &pdu)
	Processes a PDU and tries to reassemble it. More...
void	clear_streams ()
void	remove_stream (uint16_t id, IPv4Address addr1, IPv4Address addr2)
	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. More...

Detailed Description

Reassembles fragmented IP packets.

This class is fairly simple: just feed packets into it using IPv4Reassembler::process. If the return value is IPv4Reassembler::FRAGMENTED, then the packet is fragmented and we haven't yet seen the missing fragments, hence we can't reassemble it. If the function returns either IPv4Reassembler::NOT_FRAGMENTED (meaning the packet wasn't fragmented) or IPv4Reassembler::REASSEMBLED (meaning the packet was fragmented but it's now reassembled), then you can process the packet normally.

Simple example:

IPv4Reassembler reassembler;
Sniffer sniffer = ...;
sniffer.sniff_loop([&](PDU& pdu) {
    // Process it in any case, unless it's fragmented (and can't be reassembled yet)
    if (reassembler.process(pdu) != IPv4Reassembler::FRAGMENTED) {
        // Now actually process the packet
        process_packet(pdu);
    }
});

Member Enumeration Documentation

enum Tins::IPv4Reassembler::OverlappingTechnique

The type used to represent the overlapped segment reassembly technique to be used.

enum Tins::IPv4Reassembler::PacketStatus

The status of each processed packet.

Enumerator
NOT_FRAGMENTED	The given packet is not fragmented.
FRAGMENTED	The given packet is fragmented and can't be reassembled yet.
REASSEMBLED	The given packet was fragmented but is now reassembled.

Constructor & Destructor Documentation

Tins::IPv4Reassembler::IPv4Reassembler

(

)

Default constructor

Tins::IPv4Reassembler::IPv4Reassembler

(

OverlappingTechnique

technique

)

Constructs an IPV4Reassembler.

Parameters

technique

The technique to be used for reassembling overlapped fragments.

Member Function Documentation

void Tins::IPv4Reassembler::clear_streams

(

)

Removes all of the packets and data stored.

IPv4Reassembler::PacketStatus Tins::IPv4Reassembler::process

(

PDU &

pdu

)

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.

Parameters

pdu	The PDU to process.

Returns

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.

void Tins::IPv4Reassembler::remove_stream	(	uint16_t	id,
		IPv4Address	addr1,
		IPv4Address	addr2
	)

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.

Parameters

id	The idenfier to search.
addr1	The source address to search.
addr2	The destinatin address to search.

See also

IP::id

---

The documentation for this class was generated from the following files:

• /home/matias/Projects/libtins/code/include/tins/ip_reassembler.h
• /home/matias/Projects/libtins/code/src/ip_reassembler.cpp