libwifi 0.0.3
An 802.11 Frame Parsing and Generation library in C
radiotap.c File Reference
#include "platform.h"
#include "radiotap_iter.h"

Go to the source code of this file.

Functions

EXPORT 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...
 
static void find_ns (struct ieee80211_radiotap_iterator *iterator, uint32_t oui, uint8_t subns)
 
EXPORT 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...
 

Variables

static const struct radiotap_align_size rtap_namespace_sizes []
 
const struct ieee80211_radiotap_namespace radiotap_ns
 

Function Documentation

◆ find_ns()

static void find_ns ( struct ieee80211_radiotap_iterator iterator,
uint32_t  oui,
uint8_t  subns 
)
static

Definition at line 253 of file radiotap.c.

◆ ieee80211_radiotap_iterator_init()

EXPORT 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()

EXPORT 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.

Variable Documentation

◆ radiotap_ns

const struct ieee80211_radiotap_namespace radiotap_ns
Initial value:
= {
.n_bits = sizeof(rtap_namespace_sizes) / sizeof(rtap_namespace_sizes[0]),
.align_size = rtap_namespace_sizes,
}
static const struct radiotap_align_size rtap_namespace_sizes[]
Definition: radiotap.c:19

Definition at line 135 of file radiotap.c.

◆ rtap_namespace_sizes

const struct radiotap_align_size rtap_namespace_sizes[]
static

Definition at line 19 of file radiotap.c.