radiotap_iter.h File Reference

#include "platform.h"
#include "radiotap.h"
#include <stdint.h>

Go to the source code of this file.

Data Structures
struct	radiotap_override
struct	radiotap_align_size
struct	ieee80211_radiotap_namespace
struct	ieee80211_radiotap_vendor_namespaces
struct	ieee80211_radiotap_iterator
	struct ieee80211_radiotap_iterator - tracks walk thru present radiotap args @this_arg_index: index of current arg, valid after each successful call to ieee80211_radiotap_iterator_next() @this_arg: pointer to current radiotap arg; it is valid after each call to ieee80211_radiotap_iterator_next() but also after ieee80211_radiotap_iterator_init() where it will point to the beginning of the actual data portion @this_arg_size: length of the current arg, for convenience @current_namespace: pointer to the current namespace definition (or internally NULL if the current namespace is unknown) @is_radiotap_ns: indicates whether the current namespace is the default radiotap namespace or not More...

Macros
#define	CALLING_CONVENTION

Functions
IMPORT CALLING_CONVENTION int	ieee80211_radiotap_iterator_init (struct ieee80211_radiotap_iterator *iterator, struct ieee80211_radiotap_header *radiotap_header, int max_length, const struct ieee80211_radiotap_vendor_namespaces *vns)
	ieee80211_radiotap_iterator_init - radiotap parser iterator initialization @iterator: radiotap_iterator to initialize @radiotap_header: radiotap header to parse @max_length: total length we can parse into (eg, whole packet length) More...
IMPORT CALLING_CONVENTION int	ieee80211_radiotap_iterator_next (struct ieee80211_radiotap_iterator *iterator)
	ieee80211_radiotap_iterator_next - return next radiotap parser iterator arg @iterator: radiotap_iterator to move to next arg (if any) More...

Macro Definition Documentation

CALLING_CONVENTION

#define CALLING_CONVENTION

Definition at line 90 of file radiotap_iter.h.

Function Documentation

ieee80211_radiotap_iterator_init()

IMPORT CALLING_CONVENTION int ieee80211_radiotap_iterator_init	(	struct ieee80211_radiotap_iterator *	iterator,
		struct ieee80211_radiotap_header *	radiotap_header,
		int	max_length,
		const struct ieee80211_radiotap_vendor_namespaces *	vns
	)

ieee80211_radiotap_iterator_init - radiotap parser iterator initialization @iterator: radiotap_iterator to initialize @radiotap_header: radiotap header to parse @max_length: total length we can parse into (eg, whole packet length)

Returns: 0 or a negative error code if there is a problem.

This function initializes an opaque iterator struct which can then be passed to ieee80211_radiotap_iterator_next() to visit every radiotap argument which is present in the header. It knows about extended present headers and handles them.

How to use: call __ieee80211_radiotap_iterator_init() to init a semi-opaque iterator struct ieee80211_radiotap_iterator (no need to init the struct beforehand) checking for a good 0 return code. Then loop calling __ieee80211_radiotap_iterator_next()... it returns either 0, -ENOENT if there are no more args to parse, or -EINVAL if there is a problem. The iterator's @this_arg member points to the start of the argument associated with the current argument index that is present, which can be found in the iterator's @this_arg_index member. This arg index corresponds to the IEEE80211_RADIOTAP_... defines.

Radiotap header length: You can find the CPU-endian total radiotap header length in iterator->max_length after executing ieee80211_radiotap_iterator_init() successfully.

Alignment Gotcha: You must take care when dereferencing iterator.this_arg for multibyte types... the pointer is not aligned. Use get_unaligned((type *)iterator.this_arg) to dereference iterator.this_arg for type "type" safely on all arches.

Example code: parse.c

Definition at line 179 of file radiotap.c.

ieee80211_radiotap_iterator_next()

IMPORT CALLING_CONVENTION int ieee80211_radiotap_iterator_next

(

struct ieee80211_radiotap_iterator *

iterator

)

ieee80211_radiotap_iterator_next - return next radiotap parser iterator arg @iterator: radiotap_iterator to move to next arg (if any)

Returns: 0 if there is an argument to handle, -ENOENT if there are no more args or -EINVAL if there is something else wrong.

This function provides the next radiotap arg index (IEEE80211_RADIOTAP_*) in @this_arg_index and sets @this_arg to point to the payload for the field. It takes care of alignment handling and extended present fields. @this_arg can be changed by the caller (eg, incremented to move inside a compound argument like IEEE80211_RADIOTAP_CHANNEL). The args pointed to are in little-endian format whatever the endianness of your CPU.

Alignment Gotcha: You must take care when dereferencing iterator.this_arg for multibyte types... the pointer is not aligned. Use get_unaligned((type *)iterator.this_arg) to dereference iterator.this_arg for type "type" safely on all arches.

Definition at line 317 of file radiotap.c.