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Commits per author per week (path 'target/linux/bcm53xx/patches-4.1')

Author	W03 2025	W04 2025	W05 2025	W06 2025	Total
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/* * Radiotap parser * * Copyright 2007 Andy Green <andy@warmcat.com> */ #include <net/cfg80211.h> #include <net/ieee80211_radiotap.h> #include <asm/unaligned.h> /* function prototypes and related defs are in include/net/cfg80211.h */ /** * 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: * See Documentation/networking/radiotap-headers.txt */ int ieee80211_radiotap_iterator_init( struct ieee80211_radiotap_iterator *iterator, struct ieee80211_radiotap_header *radiotap_header, int max_length) { /* Linux only supports version 0 radiotap format */ if (radiotap_header->it_version) return -EINVAL; /* sanity check for allowed length and radiotap length field */ if (max_length < le16_to_cpu(get_unaligned(&radiotap_header->it_len))) return -EINVAL; iterator->rtheader = radiotap_header; iterator->max_length = le16_to_cpu(get_unaligned( &radiotap_header->it_len)); iterator->arg_index = 0; iterator->bitmap_shifter = le32_to_cpu(get_unaligned( &radiotap_header->it_present)); iterator->arg = (u8 *)radiotap_header + sizeof(*radiotap_header); iterator->this_arg = NULL; /* find payload start allowing for extended bitmap(s) */ if (unlikely(iterator->bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT))) { while (le32_to_cpu(get_unaligned((__le32 *)iterator->arg)) & (1<<IEEE80211_RADIOTAP_EXT)) { iterator->arg += sizeof(u32); /* * check for insanity where the present bitmaps * keep claiming to extend up to or even beyond the * stated radiotap header length */ if (((ulong)iterator->arg - (ulong)iterator->rtheader) > iterator->max_length) return -EINVAL; } iterator->arg += sizeof(u32); /* * no need to check again for blowing past stated radiotap * header length, because ieee80211_radiotap_iterator_next * checks it before it is dereferenced */ } /* we are all initialized happily */ return 0; } EXPORT_SYMBOL(ieee80211_radiotap_iterator_init); /** * 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 endianess 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.


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