Module org.jnetpcap

Package org.jnetpcap

Class Pcap.Linux

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.Pcap.Unix

org.jnetpcap.Pcap.Linux

All Implemented Interfaces:

AutoCloseable

Enclosing class:

Pcap

public static final class Pcap.Linux
extends Pcap.Unix

Linux only/specific calls.

Nested Class Summary

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

Pcap.LibraryPolicy, Pcap.Linux, Pcap.Unix

Field Summary

Fields inherited from class org.jnetpcap.Pcap

VERSION

Method Summary

Modifier and Type	Method	Description
static Pcap.Linux	create(String device)	Create a live capture handle.
static boolean	isSupported()	Checks if the Pcap subclass at a specific libpcap API version is natively supported.
static Pcap.Linux	openDead(PcapDlt linktype, int snaplen)	Open a fake pcap_t for compiling filters or opening a capture for output.
static Pcap.Linux	openDeadWithTstampPrecision(PcapDlt linktype, int snaplen, PcapTStampPrecision precision)	Open a fake pcap_t for compiling filters or opening a capture for output.
static Pcap.Linux	openLive(String device, int snaplen, boolean promisc, long timeout, TimeUnit unit)	Open a device for capturing.
static Pcap.Linux	openOffline(String fname)	Open a saved capture file for reading.
int	setProtocolLinux(int protocol)	Set capture protocol for a not-yet-activated capture handle.

Methods inherited from class org.jnetpcap.Pcap.Unix

getSelectableFd

Methods inherited from class org.jnetpcap.Pcap1_5

getTstampPrecision, setImmediateMode, setTstampPrecision

Methods inherited from class org.jnetpcap.Pcap1_2

listTstampTypes, setTstampType

Methods inherited from class org.jnetpcap.Pcap1_0

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

Methods inherited from class org.jnetpcap.Pcap0_9

inject, setDirection

Methods inherited from class org.jnetpcap.Pcap0_8

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

Methods inherited from class org.jnetpcap.Pcap0_7

findAllDevs, getNonBlock, setNonBlock

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, geterr, isInitialized, isSwapped, lookupDev, lookupNet, loop, loop, loop, loop, majorVersion, minorVersion, next, perror, setFilter, setUncaughtExceptionHandler, snapshot, stats, strerror

Methods inherited from class org.jnetpcap.Pcap

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

Methods inherited from class java.lang.Object

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

Method Details

create

public static Pcap.Linux 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

isSupported

public static boolean isSupported()

Checks if the Pcap subclass at a specific libpcap API version is natively supported. This is a safe method to use anytime on any platform, weather native library is present or not.

For example, Pcap1_0.isSupported() will accurately ascertain if libpcap API version 1.0 level calls are supported by the system runtime. Also a call such as WinPcap.isSupported() will determine if WinPcap related calls, ie. native WinPcap 4.1.3 or less, are supported and by extension if this is a Microsoft Windows platform.

Due to libpcap API versioning, it is safe to assume that if Pcap1_10.isSupported() returns true, that at least libpcap API version 1.0 is installed on this platform, and that all lower version calls such as libpcap 0.8 and 0.9 are available as well. The subclass hierarchy of jNetPcap module reflects the versioning of libpcap and its derivatives and the public releases of the native libraries. For example Npcap class extends WinPcap class because Npcap project took over the support for WinPcap where it left off.

Implementation notes: The check is performed by verifying that certain, subclass specific native symbols were linked with Pcap full which was introduced at a specific libpcap or related API levels.

Returns:

true, if pcap is supported up to this specific version level, otherwise false

See Also:

• Pcap.LibraryPolicy.setDefault(LibraryPolicy)

openDead

public static Pcap.Linux openDead(PcapDlt linktype,
 int snaplen)
                           throws PcapException

Open a fake pcap_t for compiling filters or opening a capture for output.

openDead(org.jnetpcap.constant.PcapDlt, int) and pcap_open_dead_with_tstamp_precision() are used for creating a pcap_t structure to use when calling the other functions in libpcap. It is typically used when just using libpcap for compiling BPF full; it can also be used if using pcap_dump_open(3PCAP), pcap_dump(3PCAP), and pcap_dump_close(3PCAP) to write a savefile if there is no pcap_t that supplies the packets to be written.

When pcap_open_dead_with_tstamp_precision(), is used to create a pcap_t for use with pcap_dump_open(), precision specifies the time stamp precision for packets; PCAP_TSTAMP_PRECISION_MICRO should be specified if the packets to be written have time stamps in seconds and microseconds, and PCAP_TSTAMP_PRECISION_NANO should be specified if the packets to be written have time stamps in seconds and nanoseconds. Its value does not affect pcap_compile(3PCAP).

Parameters:

linktype - specifies the link-layer type for the pcap handle

snaplen - specifies the snapshot length for the pcap handle

Returns:

A dead pcap handle

Throws:

PcapException - any errors

Since:

libpcap 0.6

openDeadWithTstampPrecision

public static Pcap.Linux openDeadWithTstampPrecision(PcapDlt linktype,
 int snaplen,
 PcapTStampPrecision precision)
                                              throws PcapException

Open a fake pcap_t for compiling filters or opening a capture for output.

openDead(PcapDlt, int) and openDeadWithTstampPrecision(PcapDlt, int, PcapTStampPrecision) are used for creating a pcap_t structure to use when calling the other functions in libpcap. It is typically used when just using libpcap for compiling BPF full; it can also be used if using #dumpOpen(String), PcapDumper.dump(MemorySegment, MemorySegment)^PREVIEW, and PcapDumper.close() to write a savefile if there is no pcap_t that supplies the packets to be written.

When openDeadWithTstampPrecision(PcapDlt, int, PcapTStampPrecision), is used to create a Pcap handle for use with Pcap0_4.dumpOpen(String), precision specifies the time stamp precision for packets; PCAP_TSTAMP_PRECISION_MICRO should be specified if the packets to be written have time stamps in seconds and microseconds, and PCAP_TSTAMP_PRECISION_NANO should be specified if the packets to be written have time stamps in seconds and nanoseconds. Its value does not affect pcap_compile(3PCAP).

Parameters:

linktype - specifies the link-layer type for the pcap handle

snaplen - specifies the snapshot length for the pcap handle

precision - the requested timestamp precision

Returns:

A dead pcap handle

Throws:

PcapException - any errors

Since:

libpcap 1.5.1

openLive

public static Pcap.Linux openLive(String device,
 int snaplen,
 boolean promisc,
 long timeout,
 TimeUnit unit)
                           throws PcapException

Open a device for capturing.

openLive is used to obtain a packet capture handle to look at packets on the network. device is a string that specifies the network device to open; on Linux systems with 2.2 or later kernels, a device argument of "any" or NULL can be used to capture packets from all interfaces.

Parameters:

device - the device name

snaplen - specifies the snapshot length to be set on the handle

promisc - specifies whether the interface is to be put into promiscuous mode. If promisc is non-zero, promiscuous mode will be set, otherwise it will not be set

timeout - the packet buffer timeout, as a non-negative value, in units

unit - time timeout unit

Returns:

the pcap handle

Throws:

PcapException - any errors

Since:

libpcap 0.4

openOffline

public static Pcap.Linux 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

setProtocolLinux

public int setProtocolLinux(int protocol)
                     throws PcapException

Set capture protocol for a not-yet-activated capture handle.

On network interface devices on Linux, pcap_set_protocol_linux() sets the protocol to be used in the socket(2) call to create a capture socket when the handle is activated. The argument is a link-layer protocol value, such as the values in the <linux/if_ether.h> header file, specified in host byte order. If protocol is non-zero, packets of that protocol will be captured when the handle is activated, otherwise, all packets will be captured. This function is only provided on Linux, and, if it is used on any device other than a network interface, it will have no effect. It should not be used in portable full; instead, a filter should be specified with pcap_setfilter(3PCAP).

If a given network interface provides a standard link-layer header, with a standard packet type, but provides some packet types with a different socket-layer protocol type from the one in the link-layer header, that packet type cannot be filtered with a filter specified with pcap_setfilter() but can be filtered by specifying the socket-layer protocol type using pcap_set_protocol_linux().

Parameters:

protocol - the protocol

Returns:

the int

Throws:

PcapException - the pcap exception

Since:

libpcap 0.9 (Linux only)