Module org.jnetpcap

Package org.jnetpcap.internal

Class UnsafePcapHandle

java.lang.Object

org.jnetpcap.Pcap

org.jnetpcap.Pcap0_4

org.jnetpcap.Pcap0_5

org.jnetpcap.Pcap0_6

org.jnetpcap.Pcap0_7

org.jnetpcap.Pcap0_8

org.jnetpcap.Pcap0_9

org.jnetpcap.Pcap1_0

org.jnetpcap.Pcap1_2

org.jnetpcap.Pcap1_5

org.jnetpcap.Pcap1_9

org.jnetpcap.Pcap1_10

org.jnetpcap.internal.UnsafePcapHandle

All Implemented Interfaces:

AutoCloseable

public non-sealed class UnsafePcapHandle
extends Pcap1_10

Non public unsafe Pcap handle mainly needed for jUnit testing.

Author:

Sly Technologies Inc, repos@slytechs.com, mark

Nested Class Summary

Nested classes/interfaces inherited from class org.jnetpcap.Pcap0_9

Pcap0_9.Linux0_9

Nested classes/interfaces inherited from class org.jnetpcap.Pcap0_8

Pcap0_8.Unix0_8

Nested classes/interfaces inherited from class org.jnetpcap.Pcap0_4

Pcap0_4.PcapSupplier<T extends Pcap>

Nested classes/interfaces inherited from class org.jnetpcap.Pcap

Pcap.LibraryPolicy, Pcap.Linux, Pcap.Unix

Field Summary

Fields inherited from class org.jnetpcap.Pcap0_4

dispatcher

Fields inherited from class org.jnetpcap.Pcap

closed, pcapHeaderABI, POINTER_TO_POINTER1, POINTER_TO_POINTER2, POINTER_TO_POINTER3, VERSION

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	UnsafePcapHandle(MemorySegment pcapHandle, String name, PcapHeaderABI abi)	Instantiates a new unsafe pcap handle.

Method Summary

Modifier and Type	Method	Description
MemorySegment	address()	Address.
static UnsafePcapHandle	create(String device)	Create a live capture handle.
int	dispatchWithAccessToRawPacket(int count, PcapHandler.NativeCallback handler, MemorySegment user)	Process packets from a live capture or savefile.
int	inject(MemorySegment packet, int length)	Inject.
int	loopWithAccessToRawPacket(int count, PcapHandler.NativeCallback handler)	Process packets from a live capture or savefile.
static String	makeDeadHandleName(PcapDlt dlt)	Make dead handle name.
static String	makeLiveHandleName(String device)	Make live handle name.
static String	makeOfflineHandleName(String fname)	Make offline handle name.
static UnsafePcapHandle	openOffline(String fname)	Open a saved capture file for reading.
void	sendPacket(MemorySegment packet, int length)	Send packet.

Methods inherited from class org.jnetpcap.Pcap1_10

isSupported, openDead, openDeadWithTstampPrecision, openLive

Methods inherited from class org.jnetpcap.Pcap1_5

getTstampPrecision, openDeadWithTstampPrecision, setImmediateMode, setTstampPrecision

Methods inherited from class org.jnetpcap.Pcap1_2

listTstampTypes, setTstampType

Methods inherited from class org.jnetpcap.Pcap1_0

activate, canSetRfmon, create, dataLinkExt, init, offlineFilter, setBufferSize, setPromisc, setPromisc, setRfmon, setRfmon, setSnaplen, setTimeout, statusToStr

Methods inherited from class org.jnetpcap.Pcap0_9

setDirection, setProtocolLinux

Methods inherited from class org.jnetpcap.Pcap0_8

breakloop, datalinkNameToVal, dataLinkValToDescription, dataLinkValToName, getSelectableFd, libVersion, listDataLinks, nextEx, setDatalink

Methods inherited from class org.jnetpcap.Pcap0_7

findAllDevs, getNonBlock, setNonBlock

Methods inherited from class org.jnetpcap.Pcap0_6

openDead

Methods inherited from class org.jnetpcap.Pcap0_5

compileNoPcap

Methods inherited from class org.jnetpcap.Pcap0_4

close, compile, datalink, datalinkGetAsInt, dispatch, dispatch, dispatch, dispatch, dumpOpen, file, fileno, getDispatcher, geterr, isInitialized, isSwapped, lookupDev, lookupNet, loop, loop, loop, loop, majorVersion, minorVersion, next, openLive, openOffline, perror, setDispatcher, setFilter, setUncaughtExceptionHandler, snapshot, stats, strerror

Methods inherited from class org.jnetpcap.Pcap

checkPcapVersion, compile, create, datalinkValToDescription, datalinkValToName, findAllDevsEx, getErrorString, getName, getPcapHandle, getPcapHeaderABI, init, inject, inject, inject, listAllPcapIf, loadNativePcapLibrary, lookupErrorString, lookupNet, newArena, openLive, openLive, openOffline, order, sendPacket, sendPacket, sendPacket, setDatalink, setDatalink, setDirection, setDirection, setFilter, setUncaughtExceptionHandler, statusToStr, toString

Methods inherited from class java.lang.Object

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

Constructor Details

UnsafePcapHandle

protected UnsafePcapHandle(MemorySegment pcapHandle,
 String name,
 PcapHeaderABI abi)

Instantiates a new unsafe pcap handle.

Parameters:

pcapHandle - the pcap handle

name - the name

abi - the abi

Method Details

makeDeadHandleName

public static String makeDeadHandleName(PcapDlt dlt)

Make dead handle name.

Parameters:

dlt - the dlt

Returns:

the string

makeLiveHandleName

public static String makeLiveHandleName(String device)

Make live handle name.

Parameters:

device - the device

Returns:

the string

makeOfflineHandleName

public static String makeOfflineHandleName(String fname)

Make offline handle name.

Parameters:

fname - the fname

Returns:

the string

openOffline

public static UnsafePcapHandle openOffline(String fname)
                                    throws PcapException

Open a saved capture file for reading.

pcap_open_offline() and pcap_open_offline_with_tstamp_precision() are called to open a ``savefile'' for reading.

Parameters:

fname - specifies the name of the file to open. The file can have the pcap file format as described in pcap-savefile(5), which is the file format used by, among other programs, tcpdump(1) and tcpslice(1), or can have the pcapng file format, although not all pcapng files can be read

Returns:

the pcap handle

Throws:

PcapException - any errors

Since:

libpcap 0.4

create

public static UnsafePcapHandle create(String device)
                               throws PcapException

Create a live capture handle. create is used to create a packet capture handle to look at packets on the network. source is a string that specifies the network device to open; on Linux systems with 2.2 or later kernels, a source argument of "any" or NULL can be used to capture packets from all interfaces. The returned handle must be activated with pcap_activate() before pack' ets can be captured with it; options for the capture, such as promiscu' ous mode, can be set on the handle before activating it.

Parameters:

device - a string that specifies the network device to open; on Linux systems with 2.2 or later kernels, a source argument of "any" or NULL can be used to capture packets from all interfaces.

Returns:

a new pcap object that needs to be activated using Pcap1_0.activate() call

Throws:

PcapException - the pcap exception

Since:

libpcap 1.0

address

public MemorySegment address()

Address.

Returns:

the memory segment

dispatchWithAccessToRawPacket

public int dispatchWithAccessToRawPacket(int count,
 PcapHandler.NativeCallback handler,
 MemorySegment user)

Process packets from a live capture or savefile.

Processes packets from a live capture or ``savefile'' until cnt packets are processed, the end of the current bufferful of packets is reached when doing a live capture, the end of the ``savefile'' is reached when reading from a ``savefile'', pcap_breakloop() is called, or an error occurs. Thus, when doing a live capture, cnt is the maximum number of packets to process before returning, but is not a minimum number; when reading a live capture, only one bufferful of packets is read at a time, so fewer than cnt packets may be processed. A value of -1 or 0 for cnt causes all the packets received in one buffer to be processed when reading a live capture, and causes all the packets in the file to be processed when reading a ``savefile''.

Note that, when doing a live capture on some platforms, if the read timeout expires when there are no packets available, pcap_dispatch() will return 0, even when not in non-blocking mode, as there are no packets to process. Applications should be prepared for this to happen, but must not rely on it happening.

Callback specifies a pcap_handler routine to be called with three arguments: a u_char pointer which is passed in the user argument to pcap_loop() or pcap_dispatch(), a const struct pcap_pkthdr pointer pointing to the packet time stamp and lengths, and a const u_char pointer to the first caplen (as given in the struct pcap_pkthdr a pointer to which is passed to the callback routine) bytes of data from the packet. The struct pcap_pkthdr and the packet data are not to be freed by the callback routine, and are not guaranteed to be valid after the callback routine returns; if the full needs them to be valid after the callback, it must make a copy of them.

The bytes of data from the packet begin with a link-layer header. The format of the link-layer header is indicated by the return value of the pcap_datalink(3PCAP) routine when handed the pcap_t value also passed to pcap_loop() or pcap_dispatch(). https://www.tcpdump.org/linktypes.html lists the values pcap_datalink() can return and describes the packet formats that correspond to those values. The value it returns will be valid for all packets received unless and until pcap_set_datalink(3PCAP) is called; after a successful call to pcap_set_datalink(), all subsequent packets will have a link-layer header of the type specified by the link-layer header type value passed to pcap_set_datalink().

Do NOT assume that the packets for a given capture or ``savefile`` will have any given link-layer header type, such as DLT_EN10MB for Ethernet. For example, the "any" device on Linux will have a link-layer header type of DLT_LINUX_SLL or DLT_LINUX_SLL2 even if all devices on the system at the time the "any" device is opened have some other data link type, such as DLT_EN10MB for Ethernet.

Parameters:

count - maximum number of packets to process before returning

handler - the handler

user - TODO

Returns:

the number of packets processed on success; this can be 0 if no packets were read from a live capture (if, for example, they were discarded because they didn't pass the packet filter, or if, on platforms that support a packet buffer timeout that starts before any packets arrive, the timeout expires before any packets arrive, or if the file descriptor for the capture device is in non-blocking mode and no packets were available to be read) or if no more packets are available in a ``savefile.''

Since:

libpcap 0.4

loopWithAccessToRawPacket

public int loopWithAccessToRawPacket(int count,
 PcapHandler.NativeCallback handler)

Process packets from a live capture or savefile.

Processes packets from a live capture or ``savefile'' until cnt packets are processed, the end of the current bufferful of packets is reached when doing a live capture, the end of the ``savefile'' is reached when reading from a ``savefile'', pcap_breakloop() is called, or an error occurs. Thus, when doing a live capture, cnt is the maximum number of packets to process before returning, but is not a minimum number; when reading a live capture, only one bufferful of packets is read at a time, so fewer than cnt packets may be processed. A value of -1 or 0 for cnt causes all the packets received in one buffer to be processed when reading a live capture, and causes all the packets in the file to be processed when reading a ``savefile''.

Note that, when doing a live capture on some platforms, if the read timeout expires when there are no packets available, pcap_dispatch() will return 0, even when not in non-blocking mode, as there are no packets to process. Applications should be prepared for this to happen, but must not rely on it happening.

Callback specifies a pcap_handler routine to be called with three arguments: a u_char pointer which is passed in the user argument to pcap_loop() or pcap_dispatch(), a const struct pcap_pkthdr pointer pointing to the packet time stamp and lengths, and a const u_char pointer to the first caplen (as given in the struct pcap_pkthdr a pointer to which is passed to the callback routine) bytes of data from the packet. The struct pcap_pkthdr and the packet data are not to be freed by the callback routine, and are not guaranteed to be valid after the callback routine returns; if the full needs them to be valid after the callback, it must make a copy of them.

The bytes of data from the packet begin with a link-layer header. The format of the link-layer header is indicated by the return value of the pcap_datalink(3PCAP) routine when handed the pcap_t value also passed to pcap_loop() or pcap_dispatch(). https://www.tcpdump.org/linktypes.html lists the values pcap_datalink() can return and describes the packet formats that correspond to those values. The value it returns will be valid for all packets received unless and until pcap_set_datalink(3PCAP) is called; after a successful call to pcap_set_datalink(), all subsequent packets will have a link-layer header of the type specified by the link-layer header type value passed to pcap_set_datalink().

Do NOT assume that the packets for a given capture or ``savefile`` will have any given link-layer header type, such as DLT_EN10MB for Ethernet. For example, the "any" device on Linux will have a link-layer header type of DLT_LINUX_SLL or DLT_LINUX_SLL2 even if all devices on the system at the time the "any" device is opened have some other data link type, such as DLT_EN10MB for Ethernet.

Parameters:

count - maximum number of packets to process before returning

handler - the handler

Returns:

the number of packets processed on success; this can be 0 if no packets were read from a live capture (if, for example, they were discarded because they didn't pass the packet filter, or if, on platforms that support a packet buffer timeout that starts before any packets arrive, the timeout expires before any packets arrive, or if the file descriptor for the capture device is in non-blocking mode and no packets were available to be read) or if no more packets are available in a ``savefile.''

Since:

libpcap 0.4

inject

public int inject(MemorySegment packet,
 int length)
           throws PcapException

Inject.

Overrides:

inject in class Pcap0_9

Parameters:

packet - the packet

length - the length

Returns:

the int

Throws:

PcapException - the pcap exception

See Also:

• Pcap0_9.inject(java.lang.foreign.MemorySegment, int)

sendPacket

public void sendPacket(MemorySegment packet,
 int length)
                throws PcapException

Send packet.

Overrides:

sendPacket in class Pcap0_8

Parameters:

packet - the packet

length - the length

Throws:

PcapException - the pcap exception

See Also:

• Pcap0_8.sendPacket(java.lang.foreign.MemorySegment, int)