Reassembled IP datagram interface to libpcap. More...

Enumerations
enum	nmsg_pcap_type { nmsg_pcap_type_file , nmsg_pcap_type_live }

Functions
nmsg_pcap_t	nmsg_pcap_input_open (pcap_t *phandle)
	Initialize a new nmsg_pcap_t input from a libpcap source.

nmsg_res	nmsg_pcap_input_close (nmsg_pcap_t *pcap)
	Close an nmsg_pcap_t object and release all associated resources.

nmsg_res	nmsg_pcap_input_read (nmsg_pcap_t pcap, struct nmsg_ipdg dg, struct timespec ts)
	Read an IP datagram from an nmsg_pcap_t input, performing reassembly if necessary.

nmsg_res	nmsg_pcap_input_read_raw (nmsg_pcap_t pcap, struct pcap_pkthdr pkt_hdr, const uint8_t pkt_data, struct timespec *ts)
	Read a raw packet from an nmsg_pcap_t input.

nmsg_res	nmsg_pcap_input_setfilter (nmsg_pcap_t pcap, const char *bpfstr)
	Set a bpf filter on an nmsg_pcap_t object.

nmsg_res	nmsg_pcap_input_setfilter_raw (nmsg_pcap_t pcap, const char *bpfstr)
	Set a bpf filter on an nmsg_pcap_t object.

void	nmsg_pcap_input_set_raw (nmsg_pcap_t pcap, bool raw)
	Set raw mode.

int	nmsg_pcap_snapshot (nmsg_pcap_t pcap)
	Get the snapshot length of the underlying pcap handle.

nmsg_pcap_type	nmsg_pcap_get_type (nmsg_pcap_t pcap)
	Get the type of the underlying pcap handle.

int	nmsg_pcap_get_datalink (nmsg_pcap_t pcap)
	Get the datalink type of the underlying pcap handle.

bool	nmsg_pcap_filter (nmsg_pcap_t pcap, const uint8_t *pkt, size_t len)
	Return the result of filtering a packet.

Detailed Description

Reassembled IP datagram interface to libpcap.

libpcap's frame-based interface is wrapped with calls to the ipdg.h interface and provides the caller with reassembled IP datagrams.

Callers should not call pcap_setfilter() on the pcap_t handle passed to nmsg_pcap_input_open() but should instead use nmsg_pcap_input_setfilter(). Since IP datagrams are reassembled in userspace, they must undergo reevaluation of the user-provided filter. nmsg_pcap_input_setfilter() and nmsg_pcap_input_read() handle this transparently.

Definition in file pcap_input.h.

Enumeration Type Documentation

◆ nmsg_pcap_type

enum nmsg_pcap_type

Definition at line 33 of file pcap_input.h.

Function Documentation

◆ nmsg_pcap_input_open()

nmsg_pcap_t nmsg_pcap_input_open ( pcap_t * phandle )

Initialize a new nmsg_pcap_t input from a libpcap source.

Parameters

[in] phandle pcap_t handle (e.g., acquired from pcap_open_offline() or pcap_open_live()).

Returns: Opaque pointer that is NULL on failure or non-NULL on success.

◆ nmsg_pcap_input_close()

nmsg_res nmsg_pcap_input_close ( nmsg_pcap_t * pcap )

Close an nmsg_pcap_t object and release all associated resources.

Parameters

[in] pcap pointer to an nmsg_pcap_t object.

◆ nmsg_pcap_input_read()

nmsg_res nmsg_pcap_input_read	(	nmsg_pcap_t	pcap,
		struct nmsg_ipdg *	dg,
		struct timespec *	ts
	)

Read an IP datagram from an nmsg_pcap_t input, performing reassembly if necessary.

Parameters

[in]	pcap	nmsg_pcap_t object.
[out]	dg	nmsg_ipdg structure to be filled.
[out]	ts	timespec structure indicating time of datagram reception.

Returns: nmsg_res_success; nmsg_res_pcap_error; nmsg_res_again

◆ nmsg_pcap_input_read_raw()

nmsg_res nmsg_pcap_input_read_raw	(	nmsg_pcap_t	pcap,
		struct pcap_pkthdr **	pkt_hdr,
		const uint8_t **	pkt_data,
		struct timespec *	ts
	)

Read a raw packet from an nmsg_pcap_t input.

Parameters

[in]	pcap	nmsg_pcap_t object.
[out]	pkt_hdr	Location to store pcap packet header.
[out]	pkt_data	Location to store pcap packet data.
[out]	ts	timespec structure indicating time of packet reception.

Returns: nmsg_res_success; nmsg_res_pcap_error; nmsg_res_again

◆ nmsg_pcap_input_setfilter()

nmsg_res nmsg_pcap_input_setfilter	(	nmsg_pcap_t	pcap,
		const char *	bpfstr
	)

Set a bpf filter on an nmsg_pcap_t object.

This function performs additional transformation on the bpf filter text before passing the filter to pcap_compile() and pcap_setfilter().

Parameters

[in]	pcap	nmsg_pcap_t object.
[in]	bpfstr	is a valid bpf filter expression that will be passed to pcap_compile().

Returns: nmsg_res_success; nmsg_res_failure

◆ nmsg_pcap_input_setfilter_raw()

nmsg_res nmsg_pcap_input_setfilter_raw	(	nmsg_pcap_t	pcap,
		const char *	bpfstr
	)

Set a bpf filter on an nmsg_pcap_t object.

This function is a thin wrapper for pcap_setfilter().

Parameters

[in]	pcap	nmsg_pcap_t object.
[in]	bpfstr	is a valid bpf filter expression that will be passed to pcap_compile() and pcap_setfilter().

Returns: nmsg_res_success; nmsg_res_failure

◆ nmsg_pcap_input_set_raw()

void nmsg_pcap_input_set_raw	(	nmsg_pcap_t	pcap,
		bool	raw
	)

Set raw mode.

Parameters

[in]	pcap	nmsg_pcap_t object.
[in]	raw	True if raw packets should be passed, false if reassembled datagrams should be passed.

◆ nmsg_pcap_snapshot()

int nmsg_pcap_snapshot ( nmsg_pcap_t pcap )

Get the snapshot length of the underlying pcap handle.

Parameters

[in] pcap nmsg_pcap_t object.

Returns: Pcap snapshot length.

◆ nmsg_pcap_get_type()

nmsg_pcap_type nmsg_pcap_get_type ( nmsg_pcap_t pcap )

Get the type of the underlying pcap handle.

Parameters

[in] pcap nmsg_pcap_t object.

Returns: nmsg_pcap_type_file; nmsg_pcap_type_live

◆ nmsg_pcap_get_datalink()

int nmsg_pcap_get_datalink ( nmsg_pcap_t pcap )

Get the datalink type of the underlying pcap handle.

Parameters

[in] pcap nmsg_pcap_t object.

◆ nmsg_pcap_filter()

bool nmsg_pcap_filter	(	nmsg_pcap_t	pcap,
		const uint8_t *	pkt,
		size_t	len
	)

Return the result of filtering a packet.

Parameters

[in]	pcap	nmsg_pcap_t object.
[in]	pkt	Pointer to start of network packet.
[in]	len	Length of packet.

Returns: false if packet failed the filter; true if packet passed the filter

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ nmsg_pcap_type

Function Documentation

◆ nmsg_pcap_input_open()

◆ nmsg_pcap_input_close()

◆ nmsg_pcap_input_read()

◆ nmsg_pcap_input_read_raw()

◆ nmsg_pcap_input_setfilter()

◆ nmsg_pcap_input_setfilter_raw()

◆ nmsg_pcap_input_set_raw()

◆ nmsg_pcap_snapshot()

◆ nmsg_pcap_get_type()

◆ nmsg_pcap_get_datalink()

◆ nmsg_pcap_filter()