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Make RadioTapParser work using only the options buffer

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This commit is contained in:
Matias Fontanini
2017-05-21 12:56:22 -07:00
parent b983fe0bb3
commit 988f2382c4
3 changed files with 29 additions and 20 deletions
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34
src/utils/radiotap_parser.cpp
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@@ -142,20 +142,18 @@ void align_buffer(const uint8_t* buffer_start, const uint8_t*& buffer, uint32_t
RadioTapParser::RadioTapParser(const vector<uint8_t>& buffer)
: current_namespace_(RADIOTAP_NS), current_bit_(0), namespace_index_(0) {
if (TINS_UNLIKELY(buffer.empty())) {
throw malformed_packet();
if (buffer.empty()) {
start_ = 0;
end_ = 0;
current_ptr_ = start_;
}
start_ = &*buffer.begin();
end_ = start_ + buffer.size();
const size_t max_size = end_ - start_;
if (TINS_UNLIKELY(max_size < sizeof(RadiotapHeader))) {
throw malformed_packet();
else {
start_ = &*buffer.begin();
end_ = start_ + buffer.size();
current_ptr_ = find_options_start();
// Skip all fields and make this point to the first flags one
advance_to_next_field(true /* start from bit zero */);
}
const RadiotapHeader* radio = (const RadiotapHeader*)start_;
end_ = start_ + Endian::le_to_host(radio->length);
current_ptr_ = find_options_start();
// Skip all fields and make this point to the first flags one
advance_to_next_field(true /* start from bit zero */);
}
RadioTapParser::NamespaceType RadioTapParser::current_namespace() const {
@@ -174,6 +172,10 @@ RadioTapParser::option RadioTapParser::current_option() {
return option(current_field(), size, current_ptr_);
}
const uint8_t* RadioTapParser::current_option_ptr() const {
return current_ptr_;
}
bool RadioTapParser::advance_field() {
// If we manage to advance the field, return true
if (advance_to_next_field(false /* keep going from current */)) {
@@ -190,7 +192,7 @@ bool RadioTapParser::advance_field() {
const uint8_t* RadioTapParser::find_options_start() const {
uint32_t total_sz = end_ - start_;
if (TINS_UNLIKELY(total_sz < sizeof(RadiotapHeader))) {
if (TINS_UNLIKELY(total_sz < sizeof(RadioTapFlags))) {
throw malformed_packet();
}
// Skip fields before the flags one
@@ -220,8 +222,10 @@ bool RadioTapParser::advance_to_next_field(bool start_from_zero) {
bit++;
}
if (bit < BIT_LIMIT) {
const uint8_t* radiotap_start = start_ - sizeof(uint32_t);
// Skip and align the buffer
align_buffer(start_, current_ptr_, end_ - start_, RADIOTAP_METADATA[bit].alignment);
align_buffer(radiotap_start, current_ptr_, end_ - radiotap_start,
RADIOTAP_METADATA[bit].alignment);
current_bit_ = bit;
return true;
}
@@ -257,7 +261,7 @@ bool RadioTapParser::is_field_set(uint32_t bit, const RadioTapFlags* flags) cons
}
const RadioTapFlags* RadioTapParser::get_flags_ptr() const {
return (const RadioTapFlags*)(start_ + sizeof(uint32_t) * (namespace_index_ + 1));
return (const RadioTapFlags*)(start_ + sizeof(uint32_t) * namespace_index_);
}
} // Utils