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* @(#) $Header: /usr/cvsroot/winpcap/dox/libpcap/funcs/pcap.h,v 1.18 2004/06/23 08:29:17 varenni Exp $ (LBL)
*/
/** @defgroup wpcapfunc Exported functions
* @ingroup wpcap
* Functions exported by wpcap.dll
* @{
*/
/** \name Deprecated Functions
These functions should be avoided because they have been replaced
with something else.
*/
//\{
/*! \brief It opens a live capture from the network.
\deprecated Use the pcap_open() instead.
pcap_open_live() is used to obtain a packet capture
descriptor 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. snaplen specifies the maximum number of bytes
to capture. promisc specifies if the interface is to be
put into promiscuous mode. (Note that even if this parameter
is false, the interface could well be in promiscuous
mode for some other reason.) For now, this doesn't work
on the "any" device; if an argument of "any" or NULL is
supplied, the promisc flag is ignored. to_ms specifies
the read timeout in milliseconds. The read timeout is
used to arrange that the read not necessarily return immediately
when a packet is seen, but that it wait for some
amount of time to allow more packets to arrive and to read
multiple packets from the OS kernel in one operation. Not
all platforms support a read timeout; on platforms that
don't, the read timeout is ignored. errbuf is used to
return error or warning text. It will be set to error
text when pcap_open_live() fails and returns NULL. errbuf
may also be set to warning text when pcap_open_live() succeds;
to detect this case the caller should store a zero
length string in errbuf before calling pcap_open_live()
and display the warning to the user if errbuf is no longer
a zero-length string.
\sa pcap_open_offline(), pcap_open_dead(), pcap_findalldevs(), pcap_close()
*/
pcap_t *pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, char *ebuf);
/*! \brief It creates a pcap_t structure without starting a capture.
\deprecated Use the pcap_open() instead.
pcap_open_dead() is 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
code.
\sa pcap_open_offline(), pcap_open_live(), pcap_findalldevs(), pcap_compile(), pcap_setfilter(), pcap_close()
*/
pcap_t *pcap_open_dead(int linktype, int snaplen);
/*! \brief It opens a savefile in the tcpdump/libpcap format to read the packets.
\deprecated Use the pcap_open() instead.
pcap_open_offline() is called to open a "savefile" for
reading. fname specifies the name of the file to open.
The file has the same format as those used by tcpdump(1)
and tcpslice(1). The name "-" in a synonym for stdin.
errbuf is used to return error text and is only set when
pcap_open_offline() fails and returns NULL.
\sa pcap_open_live(), pcap_dump_open(), pcap_findalldevs(), pcap_close()
*/
pcap_t *pcap_open_offline(const char *fname, char *errbuf);
/*! \brief Deprecated
\deprecated Use the pcap_findalldevs_ex() instead.
It returns the list of the interfaces available on the system.
pcap_findalldevs() constructs a list of network devices
that can be opened with pcap_open_live(). (Note that
there may be network devices that cannot be opened with
pcap_open_live() by the process calling pcap_findalldevs(),
because, for example, that process might not
have sufficient privileges to open them for capturing; if
so, those devices will not appear on the list.) alldevsp
is set to point to the first element of the list; each
element of the list is of type pcap_if_t.
\sa struct pcap_if, pcap_freealldevs(), pcap_open_live(), pcap_lookupdev(), pcap_lookupnet()
*/
int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf);
/*! \brief It returns the first valid device in the system.
\deprecated Use the pcap_findalldevs_ex() instead.
pcap_lookupdev() returns a pointer to a network device
suitable for use with pcap_open_live() and pcap_lookupnet().
If there is an error, NULL is returned and errbuf
is filled in with an appropriate error message.
\sa pcap_findalldevs(), pcap_open_live()
*/
char *pcap_lookupdev(char *errbuf);
/*! \brief It returns the subnet and netmask of an interface.
\deprecated Use the pcap_findalldevs_ex() instead.
pcap_lookupnet() is used to determine the network number
and mask associated with the network device device. Both
netp and maskp are bpf_u_int32 pointers. A return of -1
indicates an error in which case errbuf is filled in with
an appropriate error message.
\sa pcap_findalldevs()
*/
int pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp, char *errbuf);
//\}
// End of deprecated functions
/** \name Discouraged Functions
These functions are still valid, but we suggest to avoid their use and replace these calls
with something else.
*/
//\{
/*! \brief It collects a group of packets.
\deprecated Use the pcap_next_ex() instead.
It returns when \b cnt packets have been received
or when the timeout set with pcap_open_live() expires.
pcap_dispatch() is used to collect and process packets.
cnt specifies the maximum number of packets to process
before returning. This 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 cnt of -1 processes all the packets received in
one buffer when reading a live capture, or all the packets
in the file when reading a "savefile". callback specifies
a routine to be called with three arguments: a u_char
pointer which is passed in from pcap_dispatch(), a pointer
packet data.
The number of packets read is returned. 0 is returned 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 read 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." A return of -1 indicates an
error in which case pcap_perror() or pcap_geterr() may be
used to display the error text.
\note when reading a live capture, pcap_dispatch() will
not necessarily return when the read times out; on some
platforms, the read timeout isn't supported, and, on other
platforms, the timer doesn't start until at least one
packet arrives. This means that the read timeout should
NOT be used in, for example, an interactive application,
to allow the packet capture loop to "poll" for user
input periodically, as there's no guarantee that pcap_dispatch()
will return after the timeout expires.
\sa pcap_loop(), pcap_next(), pcap_open_live(), pcap_open_offline(), pcap_handler
*/
int pcap_dispatch(pcap_t *p, int cnt, pcap_handler callback, u_char *user);
/*! \brief It collects a group of packets.
\deprecated Use the pcap_next_ex() instead.
Returns when \b cnt packets have been received, but doesn't respect
the timeout set with pcap_open_live(), therefore it can block forever.
pcap_loop() is similar to pcap_dispatch() except it keeps
reading packets until cnt packets are processed or an
error occurs. It does not return when live read timeouts
occur. Rather, specifying a non-zero read timeout to
pcap_open_live() and then calling pcap_dispatch() allows
the reception and processing of any packets that arrive
when the timeout occurs. A negative cnt causes
pcap_loop() to loop forever (or at least until an error
occur s).
\sa pcap_dispatch(), pcap_next(), pcap_open_live(), pcap_open_offline(), pcap_handler
*/
int pcap_loop(pcap_t *p, int cnt, pcap_handler callback, u_char *user);
/*! \brief It returns the next available packet.
\deprecated Use the pcap_next_ex() instead.
pcap_next() reads the next packet (by calling pcap_dispatch()
with a cnt of 1) and returns a u_char pointer to
the data in that packet. (The pcap_pkthdr struct for that
packet is not supplied.)
\sa pcap_dispatch(), pcap_loop()
*/
u_char *pcap_next(pcap_t *p, struct pcap_pkthdr *h);
/*! \brief It returns statistics on current capture.
\deprecated Use the pcap_next_ex() instead.
pcap_stats() returns 0 and fills in a pcap_stat struct.
The values represent packet statistics from the start of
the run to the time of the call. If there is an error or
the underlying packet capture doesn't support packet
statistics, -1 is returned and the error text can be
obtained with pcap_perror() or pcap_geterr().
pcap_stats() is supported only on live captures, not on
"savefiles"; no statistics are stored in "savefiles",
so no statistics are available when reading from a "savefile".
\sa pcap_stats_ex(), pcap_open_live()
*/
int pcap_stats(pcap_t *p, struct pcap_stat *ps);
/*! \brief It returns the stdio stream of an offile capture.
\deprecated Use the pcap_dump() instead.
pcap_file() returns the standard I/O stream of the "savefile",
if a "savefile" was opened with
pcap_open_offline(), or NULL, if a network device was
opened with pcap_open_live().
\sa pcap_open_offline(), pcap_open_live()
*/
FILE *pcap_file(pcap_t *p);
/*! \brief It returns the file descriptor of a capture device.
\deprecated This function has different behaviours in Unix and Win32.
pcap_fileno() returns the file descriptor number from
which captured packets are read, if a network device was
opened with pcap_open_live(), or -1, if a "savefile" was
opened with pcap_open_offline().
\sa pcap_open_offline(), pcap_open_live()
*/
int pcap_fileno(pcap_t *p);
//\}
// End of discouraged functions
/** \name Basic functions
This section lists the most important functions exported by the WinPcap library.
*/
//\{
/*! \brief Frees an interface list returned by pcap_findalldevs().
pcap_freealldevs() is used to free a list allocated by pcap_findalldevs().
\sa pcap_findalldevs()
*/
void pcap_freealldevs(pcap_if_t *alldevsp);
/*! \brief Compiles a packet filter. Converts an high level filtering expression
(see \ref language) in a program that can be interpreted by the kernel-level
filtering engine.
pcap_compile() is used to compile the string str into a
filter program. program is a pointer to a bpf_program
struct and is filled in by pcap_compile(). optimize controls
whether optimization on the resulting code is performed.
netmask specifies the netmask of the local net.
A return of -1 indicates an error in which case
pcap_geterr() may be used to display the error text.
\sa pcap_open_live(), pcap_setfilter(), pcap_freecode(), pcap_snapshot()
*/
int pcap_compile(pcap_t *p, struct bpf_program *fp, char *str, int optimize, bpf_u_int32 netmask);
/*!\brief Compiles a packet filter without the need of opening an adapter. Converts an high level filtering expression
(see \ref language) in a program that can be interpreted by the kernel-level filtering engine.
pcap_compile_nopcap() is similar to pcap_compile() except
that instead of passing a pcap structure, one passes the
snaplen and linktype explicitly. It is intended to be
used for compiling filters for direct BPF usage, without
necessarily having called pcap_open(). A return of -1
indicates an error; the error text is unavailable.
(pcap_compile_nopcap() is a wrapper around
pcap_open_dead(), pcap_compile(), and pcap_close(); the
latter three routines can be used directly in order to get
the error text for a compilation error.)
Look at the \ref language section for details on the
str parameter.
\sa pcap_open_live(), pcap_setfilter(), pcap_freecode(), pcap_snapshot()
*/
int pcap_compile_nopcap(int snaplen_arg, int linktype_arg, struct bpf_program *program, char *buf, int optimize, bpf_u_int32 mask);
/*! \brief Associates a filter to a capture.
pcap_setfilter() is used to specify a filter program. fp
is a pointer to a bpf_program struct, usually the result
of a call to pcap_compile(). -1 is returned on failure,
in which case pcap_geterr() may be used to display the
error text; 0 is returned on success.
\sa pcap_compile(), pcap_compile_nopcap()
*/
int pcap_setfilter(pcap_t *p, struct bpf_program *fp);
/*! \brief Frees a filter.
pcap_freecode() is used to free up allocated memory
pointed to by a bpf_program struct generated by pcap_compile()
when that BPF program is no longer needed, for
example after it has been made the filter program for a
pcap structure by a call to pcap_setfilter().
\sa pcap_compile(), pcap_compile_nopcap()
*/
void pcap_freecode(struct bpf_program *fp);
/*! \brief Win32 Specific. It returns if a given filter applies to an offline packet.
This function is used to apply a filter to a packet that is currently in memory.
This process does not need to open an adapter; we need just to create the proper filter (by settings
parameters like the snapshot length, or the link-layer type) by means of the pcap_compile_nopcap().
The current API of libpcap does not allow to receive a packet and to filter the packet after it has been
received. However, this can be useful in case you want to filter packets in the application, instead of into
the receiving process. This function allows you to do the job.
\param prog: bpf program (created with the pcap_compile_nopcap() )
\param header: header of the packet that has to be filtered
\param pkt_data: buffer containing the packet, in network-byte order.
\return the length of the bytes that are currently available into the packet if the packet satisfies the filter,
0 otherwise.
*/
bool pcap_offline_filter(struct bpf_program *prog, const struct pcap_pkthdr *header, const u_char *pkt_data);
/*! \brief Opens a file to write the network traffic.
pcap_dump_open() is called to open a "savefile" for
writing. fname is the name of the file to open.
The name "-" in a synonym for stdout. If NULL is returned,
pcap_geterr() can be used to get the error text.
\sa pcap_dump_close(), pcap_file(), pcap_dump ()
*/
pcap_dumper_t *pcap_dump_open(pcap_t *p, const char *fname);
/*!\brief Saves a packet to disk.
pcap_dump() outputs a packet to the "savefile" opened
with pcap_dump_open(). Note that its calling arguments
are suitable for use with pcap_dispatch() or pcap_loop().
If called directly, the user parameter is of type
pcap_dumper_t as returned by pcap_dump_open().
\sa pcap_dump_open(), pcap_dump_close(), pcap_dispatch(), pcap_loop()
*/
void pcap_dump(u_char *user, const struct pcap_pkthdr *h, const u_char *sp);
/*! \brief
closes the files associated with p and deallocates resources.
\sa pcap_open_live(), pcap_open_offline(), pcap_open_dead()
*/
void pcap_close(pcap_t *p);
/*! \brief
pcap_dump_close() closes the "savefile".
\sa pcap_dump_open(), pcap_dump()
*/
void pcap_dump_close(pcap_dumper_t *p);
/*! \brief Read a packet from an interface or from an offline capture.
This function is used to retrieve the next available packet, bypassing the callback method traditionally
provided by libpcap.
pcap_next_ex fills the pkt_header and pkt_data parameters (see pcap_handler()) with the pointers to the
header and to the data of the next captured packet.
The return value can be:
- 1 if the packet has been read without problems
- 0 if the timeout set with pcap_open_live() has elapsed. In this case pkt_header and pkt_data don't point to a valid packet
- -1 if an error occurred
- -2 if EOF was reached reading from an offline capture
\sa pcap_open_live(), pcap_loop(), pcap_dispatch(), pcap_handler()
*/
int pcap_next_ex(pcap_t *p, struct pcap_pkthdr **pkt_header, const u_char **pkt_data);
/*! \brief Win32 Specific. Saves a capture to file.
pcap_live_dump() dumps the network traffic from an interface to
a file. Using this function the dump is performed at kernel level, therefore it is more efficient than using
pcap_dump().
The parameters of this function are an interface descriptor (obtained with pcap_open_live()), a string with
the name of the dump file, the maximum size of the file (in bytes) and the maximum number of packets that the file
will contain. Setting maxsize or maxpacks to 0 means no limit. When maxsize or maxpacks are reached,
the dump ends.
pcap_live_dump() is non-blocking, threfore it returns immediately. pcap_live_dump_ended() can be used to
check the status of the dump process or to wait until it is finished. pcap_close() can instead be used to
end the dump process.
Note that when one of the two limits is reached, the dump is stopped, but the file remains opened. In order
to correctly flush the data and put the file in a consistent state, the adapter must be closed with
pcap_close().
\sa pcap_live_dump_ended(), pcap_open_live(), pcap_close(), pcap_dump_open(), pcap_dump()
*/
int pcap_live_dump(pcap_t *p, char *filename, int maxsize, int maxpacks);
/*! \brief Win32 Specific. Returns the status of the kernel dump process, i.e. tells if one of the limits defined with pcap_live_dump() has been reached.
pcap_live_dump_ended() informs the user about the limits that were set with a previous call to
pcap_live_dump() on the interface pointed by p: if the return value is nonzero, one of the limits has been
reched and the dump process is currently stopped.
If sync is nonzero, the function blocks until the dump is finished, otherwise it returns immediately.
\warning if the dump process has no limits (i.e. if the maxsize and maxpacks arguments of pcap_live_dump()
were both 0), the dump process will never stop, therefore setting sync to TRUE will block the application
on this call forever.
\sa pcap_live_dump()
*/
int pcap_live_dump_ended(pcap_t *p, int sync);
/*! \brief Win32 Specific. Returns statistics on current capture.
pcap_stats_ex() extends the pcap_stats() allowing to return more statistical parameters than the old call.
One of the advantages of this new call is that the pcap_stat structure is not allocated by the user; instead,
it is returned back by the system. This allow to extend the pcap_stat structure without affecting backward compatibility
on older applications. These will simply check at the values of the members at the beginning of the structure,
while only newest applications are able to read new statistical values, which are appended in tail.
To be sure not to read a piece of mamory which has not been allocated by the system, the variable pcap_stat_size
will return back the size of the structure pcap_stat allocated by the system.
\param p: pointer to the pcap_t currently in use.
\param pcap_stat_size: pointer to an integer that will contain (when the function returns back) the size of the
structure pcap_stat as it has been allocated by the system.
\return: a pointer to a pcap_stat structure, that will contain the statistics related to the current device.
The return value is NULL in case of errors, and the error text can be obtained with pcap_perror() or pcap_geterr().
\warning pcap_stats_ex() is supported only on live captures, not on "savefiles"; no statistics are stored in
"savefiles", so no statistics are available when reading from a "savefile".
\sa pcap_stats()
*/
struct pcap_stat *pcap_stats_ex(pcap_t *p, int *pcap_stat_size);
/*! \brief Prototype of the callback function that receives the packets.
When pcap_dispatch() or pcap_loop() are called by the user, the packets are passed to the application
by means of this callback. user is a user-defined parameter that contains the state of the
capture session, it corresponds to the \e user parameter of pcap_dispatch() and pcap_loop(). pkt_header is
the header associated by the capture driver to the packet. It is NOT a protocol header. pkt_data
points to the data of the packet, including the protocol headers.
*/
typedef void (*pcap_handler)(u_char *user, const struct pcap_pkthdr *pkt_header,
const u_char *pkt_data);
//\}
// End of basic functions
/** \name Miscellaneous functions
This section lists the helper functions exported by the WinPcap library.
*/
//\{
/*! \brief Switches between blocking and nonblocking mode.
pcap_setnonblock() puts a capture descriptor, opened with
pcap_open_live(), into "non-blocking" mode, or takes it
out of "non-blocking" mode, depending on whether the
nonblock argument is non-zero or zero. It has no effect
on "savefiles". If there is an error, -1 is returned
and errbuf is filled in with an appropriate error message;
otherwise, 0 is returned. In "non-blocking" mode, an
attempt to read from the capture descriptor with pcap_dispatch()
will, if no packets are currently available to be
read, return 0 immediately rather than blocking waiting
for packets to arrive. pcap_loop() and pcap_next() will
not work in "non-blocking" mode.
\sa pcap_getnonblock(), pcap_dispatch()
*/
int pcap_setnonblock(pcap_t *p, int nonblock, char *errbuf);
/*! \brief Gets the "non-blocking" state of an interface.
pcap_getnonblock() returns the current "non-blocking"
state of the capture descriptor; it always returns 0 on
"savefiles". If there is an error, -1 is returned and
errbuf is filled in with an appropriate error message.
\sa pcap_setnonblock()
*/
int pcap_getnonblock(pcap_t *p, char *errbuf);
/*! \brief Win32 Specific. Sets the size of the kernel buffer associated with an adapter.
\e dim specifies the size of the buffer in bytes.
The return value is 0 when the call succeeds, -1 otherwise. If an old buffer was already created
with a previous call to pcap_setbuff(), it is deleted and its content is discarded.
pcap_open_live() creates a 1 MByte buffer by default.
\sa pcap_open_live(), pcap_loop(), pcap_dispatch()
*/
int pcap_setbuff(pcap_t *p, int dim);
/*! \brief Win32 Specific. Sets the working mode of the interface p to mode.
Valid values for mode are
MODE_CAPT (default capture mode) and MODE_STAT (statistical mode). See the tutorial "\ref wpcap_tut9"
for details about statistical mode.
*/
int pcap_setmode(pcap_t *p, int mode);
/*! \brief Win32 Specific. Sets the minumum amount of data received by the kernel in a single call.
pcap_setmintocopy() changes the minimum amount of data in the kernel buffer that causes a read from
the application to return (unless the timeout expires). If the value of \e size is large, the kernel
is forced to wait the arrival of several packets before copying the data to the user. This guarantees
a low number of system calls, i.e. low processor usage, and is a good setting for applications like
packet-sniffers and protocol analyzers. Vice versa, in presence of a small value for this variable,
the kernel will copy the packets as soon as the application is ready to receive them. This is useful
for real time applications that need the best responsiveness from the kernel.
\sa pcap_open_live(), pcap_loop(), pcap_dispatch()
*/
int pcap_setmintocopy(pcap_t *p, int size);
/*! \brief Returns the link layer of an adapter.
pcap_datalink() returns the link layer type; link layer
types it can return include:
- DLT_NULL
BSD loopback encapsulation; the link layer
header is a 4-byte field, in host byte order,
containing a PF_ value from socket.h for the
network-layer protocol of the packet
Note that "host byte order" is the byte order
of the machine on which the packets are captured,
and the PF_ values are for the OS of the
machine on which the packets are captured; if a
live capture is being done, "host byte order"
is the byte order of the machine capturing the
packets, and the PF_ values are those of the OS
of the machine capturing the packets, but if a
"savefile" is being read, the byte order and
PF_ values are not necessarily those of the
machine reading the capture file.
- DLT_EN10MB
Ethernet (10Mb, 100Mb, 1000Mb, and up)
- DLT_IEEE802
IEEE 802.5 Token Ring
- DLT_ARCNET
ARCNET
SLIP; the link layer header contains, in order:
a 1-byte flag, which is 0 for packets
received by the machine and 1 for packets
sent by the machine;
a 1-byte field, the upper 4 bits of which
indicate the type of packet, as per RFC
1144:
- 0x40 an unmodified IP datagram
(TYPE_IP);
- 0x70 an uncompressed-TCP IP datagram
(UNCOMPRESSED_TCP), with that
byte being the first byte of the
raw IP header on the wire, containing
the connection number in
the protocol field;
- 0x80 a compressed-TCP IP datagram
(COMPRESSED_TCP), with that byte
being the first byte of the compressed
TCP/IP datagram header;
for UNCOMPRESSED_TCP, the rest of the modified
IP header, and for COMPRESSED_TCP, the
compressed TCP/IP datagram header;
for a total of 16 bytes; the uncompressed IP
datagram follows the header
- DLT_PPP
PPP; if the first 2 bytes are 0xff and 0x03,
it's PPP in HDLC-like framing, with the PPP
header following those two bytes, otherwise it's
PPP without framing, and the packet begins with
the PPP header
- DLT_FDDI
FDDI
- DLT_ATM_RFC1483
RFC 1483 LLC/SNAP-encapsulated ATM; the packet
begins with an IEEE 802.2 LLC header
- DLT_RAW
raw IP; the packet begins with an IP header
- DLT_PPP_SERIAL
PPP in HDLC-like framing, as per RFC 1662, or
Cisco PPP with HDLC framing, as per section
or 0x8F for Cisco PPP with HDLC framing
- DLT_PPP_ETHER
PPPoE; the packet begins with a PPPoE header, as
per RFC 2516
- DLT_C_HDLC
Cisco PPP with HDLC framing, as per section
4.3.1 of RFC 1547
- DLT_IEEE802_11
IEEE 802.11 wireless LAN
- DLT_LOOP
OpenBSD loopback encapsulation; the link layer
header is a 4-byte field, in network byte order,
containing a PF_ value from OpenBSD's socket.h
for the network-layer protocol of the packet
Note that, if a "savefile" is being read,
those PF_ values are not necessarily those of
the machine reading the capture file.
- DLT_LINUX_SLL
Linux "cooked" capture encapsulation; the link
layer header contains, in order:
a 2-byte "packet type", in network byte
order, which is one of:
- 0 packet was sent to us by somebody
else
- 1 packet was broadcast by somebody
else
- 2 packet was multicast, but not
broadcast, by somebody else
- 3 packet was sent by somebody else
to somebody else
- 4 packet was sent by us
a 2-byte field, in network byte order, containing
a Linux ARPHRD_ value for the link
layer device type;
a 2-byte field, in network byte order, containing
the length of the link layer
address of the sender of the packet (which
could be 0);
bytes of the link layer header (if there
are more than 8 bytes, only the first 8 are
present);
a 2-byte field containing an Ethernet protocol
type, in network byte order, or containing
1 for Novell 802.3 frames without
an 802.2 LLC header or 4 for frames beginning
with an 802.2 LLC header.
- DLT_LTALK
Apple LocalTalk; the packet begins with an
AppleTalk LLAP header
*/
int pcap_datalink(pcap_t *p);
/*! \brief Returns the dimension of the packet portion (in bytes) that is delivered to the application.
pcap_snapshot() returns the snapshot length specified when
pcap_open_live was called.
\sa pcap_open_live(), pcap_compile(), pcap_compile_nopcap()
*/
int pcap_snapshot(pcap_t *p);
/*! \brief
returns true if the current savefile
uses a different byte order than the current system.
*/
int pcap_is_swapped(pcap_t *p);
/*! \brief
returns the major version number of the pcap library used to write the savefile.
\sa pcap_minor_version()
*/
int pcap_major_version(pcap_t *p);
/*! \brief
returns the minor version number of the pcap library used to write the savefile.
\sa pcap_major_version()
*/
int pcap_minor_version(pcap_t *p);
/*! \brief Win32 Specific. Returns the handle of the event associated with the interface p.
This event can be passed to functions like WaitForSingleObject() or WaitForMultipleObjects() to wait
until the driver's buffer contains some data without performing a read.
We disourage the use of this function because it is not portable.
\sa pcap_open_live()
*/
HANDLE pcap_getevent(pcap_t *p);
/*! \brief
prints the text of the last pcap library
error on stderr, prefixed by prefix.
\sa pcap_geterr()
*/
void pcap_perror(pcap_t *p, char *prefix);
/*! \brief
returns the error text pertaining to the
last pcap library error.
\note the pointer it returns will no longer point to a valid
error message string after the pcap_t passed to it is closed;
you must use or copy the string before closing the pcap_t.
\sa pcap_perror()
*/
char *pcap_geterr(pcap_t *p);
/*! \brief
pcap_strerror() is provided in case strerror() isn't
available.
\sa pcap_perror(), pcap_geterr()
*/
char *pcap_strerror(int error);
//\}
// End of miscellaneous functions
/** \name Sending functions
This section lists the functions that are available for sending raw packets on the network.
These functions are WinPcap specific.
*/
//\{
/*! \brief Win32 Specific. Sends a raw packet.
This function allows to send a raw packet to the network. p is the interface that
will be used to send the packet, buf contains the data of the packet to send (including the various
protocol headers), size is the dimension of the buffer pointed by buf, i.e. the size of the packet to send.
The MAC CRC doesn't need to be included, because it is transparently calculated and added by the network
interface driver.
The return value is 0 if the packet is succesfully sent, -1 otherwise.
\sa pcap_open_live()
*/
int pcap_sendpacket(pcap_t *p, u_char *buf, int size);
/*! \brief Win32 Specific. Allocate a send queue.
This function allocates a send queue, i.e. a buffer containing a set of raw packets that will be transimtted
on the network with pcap_sendqueue_transmit().
memsize is the size, in bytes, of the queue, therefore it determines the maximum amount of data that the
queue will contain.
Use pcap_sendqueue_queue() to insert packets in the queue.
\sa pcap_sendqueue_queue(), pcap_sendqueue_transmit(), pcap_sendqueue_destroy()
*/
pcap_send_queue* pcap_sendqueue_alloc(u_int memsize);
/*! \brief Win32 Specific. Destroy a send queue.
Deletes a send queue and frees all the memory associated with it.
\sa pcap_sendqueue_alloc(), pcap_sendqueue_queue(), pcap_sendqueue_transmit()
*/
void pcap_sendqueue_destroy(pcap_send_queue* queue);
/*! \brief Win32 Specific. Add a packet to a send queue.
pcap_sendqueue_queue() adds a packet at the end of the send queue pointed by the queue parameter.
pkt_header points to a pcap_pkthdr structure with the timestamp and the length of the packet, pkt_data
points to a buffer with the data of the packet.
The pcap_pkthdr structure is the same used by WinPcap and libpcap to store the packets in a file,
therefore sending a capture file is straightforward.
'Raw packet' means that the sending application will have to include the protocol headers, since every packet
is sent to the network 'as is'. The CRC of the packets needs not to be calculated, because it will be
transparently added by the network interface.
\sa pcap_sendqueue_alloc(), pcap_sendqueue_transmit(), pcap_sendqueue_destroy()
*/
int pcap_sendqueue_queue(pcap_send_queue* queue, const struct pcap_pkthdr *pkt_header, const u_char *pkt_data);
/*! \brief Win32 Specific. Sends a queue of raw packets to the network.
This function transmits the content of a queue to the wire. p is a
pointer to the adapter on which the packets will be sent, queue points to a pcap_send_queue structure
containing the packets to send (see pcap_sendqueue_alloc() and pcap_sendqueue_queue()), sync determines if the
send operation must be synchronized: if it is non-zero, the packets are sent respecting the timestamps,
otherwise they are sent as fast as possible.
The return value is the amount of bytes actually sent. If it is smaller than the size parameter, an
error occurred during the send. The error can be caused by a driver/adapter problem or by an inconsistent/bogus
send queue.
\note Using this function is more efficient than issuing a series of pcap_sendpacket(), because the packets are
buffered in the kernel driver, so the number of context switches is reduced. Therefore, expect a better
throughput when using pcap_sendqueue_transmit.
\note When Sync is set to TRUE, the packets are synchronized in the kernel with a high precision timestamp.
This requires a non-negligible amount of CPU, but allows normally to send the packets with a precision of some
microseconds (depending on the accuracy of the performance counter of the machine). Such a precision cannot
be reached sending the packets with pcap_sendpacket().
\sa pcap_sendqueue_alloc(), pcap_sendqueue_queue(), pcap_sendqueue_destroy()
*/
u_int pcap_sendqueue_transmit(pcap_t *p, pcap_send_queue* queue, int sync);
//\}
// End of sending functions
/*@}*/