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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "wificond/net/nl80211_attribute.h"
using std::string;
using std::vector;
namespace android {
namespace wificond {
// Explicit instantiation
template class NL80211Attr<uint8_t>;
template class NL80211Attr<uint16_t>;
template class NL80211Attr<uint32_t>;
template class NL80211Attr<uint64_t>;
template class NL80211Attr<vector<uint8_t>>;
template class NL80211Attr<string>;
// For BaseNL80211Attr
void BaseNL80211Attr::InitHeaderAndResize(int attribute_id,
int payload_length) {
data_.resize(NLA_HDRLEN + NLA_ALIGN(payload_length), 0);
nlattr* header = reinterpret_cast<nlattr*>(data_.data());
header->nla_type = attribute_id;
header->nla_len = NLA_HDRLEN + payload_length;
}
int BaseNL80211Attr::GetAttributeId() const {
const nlattr* header = reinterpret_cast<const nlattr*>(data_.data());
return header->nla_type;
}
bool BaseNL80211Attr::IsValid() const {
if (data_.size() < NLA_HDRLEN) {
return false;
}
const nlattr* header = reinterpret_cast<const nlattr*>(data_.data());
return NLA_ALIGN(header->nla_len) == data_.size();
}
const vector<uint8_t>& BaseNL80211Attr::GetConstData() const {
return data_;
}
bool BaseNL80211Attr::GetAttributeImpl(const uint8_t* buf,
size_t len,
int attr_id,
uint8_t** attr_start,
uint8_t** attr_end) {
// Skip the top level attribute header.
const uint8_t* ptr = buf;
const uint8_t* end_ptr = buf + len;
while (ptr + NLA_HDRLEN <= end_ptr) {
const nlattr* header = reinterpret_cast<const nlattr*>(ptr);
if (header->nla_type == attr_id) {
if (ptr + NLA_ALIGN(header->nla_len) > end_ptr) {
LOG(ERROR) << "Failed to get attribute: broken nl80211 atrribute.";
return false;
}
if (attr_start != nullptr && attr_end != nullptr) {
*attr_start = const_cast<uint8_t*>(ptr);
*attr_end = const_cast<uint8_t*>(ptr + NLA_ALIGN(header->nla_len));
}
return true;
}
ptr += NLA_ALIGN(header->nla_len);
}
return false;
}
// For NL80211Attr<std::vector<uint8_t>>
NL80211Attr<vector<uint8_t>>::NL80211Attr(int id,
const vector<uint8_t>& raw_buffer) {
size_t size = raw_buffer.size();
InitHeaderAndResize(id, size);
memcpy(data_.data() + NLA_HDRLEN, raw_buffer.data(), raw_buffer.size());
}
NL80211Attr<vector<uint8_t>>::NL80211Attr(
const vector<uint8_t>& data) {
data_ = data;
}
vector<uint8_t> NL80211Attr<vector<uint8_t>>::GetValue() const {
const nlattr* header = reinterpret_cast<const nlattr*>(data_.data());
return vector<uint8_t>(
data_.data() + NLA_HDRLEN,
data_.data() + header->nla_len);
}
// For NL80211Attr<std::string>
NL80211Attr<string>::NL80211Attr(int id, const string& str) {
size_t size = str.size();
// This string is storaged as a null-terminated string.
// Buffer is initialized with 0s so we only need to make a space for
// the null terminator.
InitHeaderAndResize(id, size + 1);
char* storage = reinterpret_cast<char*>(data_.data() + NLA_HDRLEN);
str.copy(storage, size);
}
NL80211Attr<string>::NL80211Attr(const vector<uint8_t>& data) {
data_ = data;
}
string NL80211Attr<string>::GetValue() const {
const nlattr* header = reinterpret_cast<const nlattr*>(data_.data());
size_t str_length = header->nla_len - NLA_HDRLEN;
// Remove trailing zeros.
while (str_length > 0 &&
*(data_.data() + NLA_HDRLEN + str_length - 1) == 0) {
str_length--;
}
return string(reinterpret_cast<const char*>(data_.data() + NLA_HDRLEN),
str_length);
}
// For NL80211NestedAttr
NL80211NestedAttr::NL80211NestedAttr(int id) {
InitHeaderAndResize(id, 0);
}
NL80211NestedAttr::NL80211NestedAttr(const vector<uint8_t>& data) {
data_ = data;
}
void NL80211NestedAttr::AddAttribute(const BaseNL80211Attr& attribute) {
const vector<uint8_t>& append_data = attribute.GetConstData();
// Append the data of |attribute| to |this|.
data_.insert(data_.end(), append_data.begin(), append_data.end());
nlattr* header = reinterpret_cast<nlattr*>(data_.data());
// We don't need to worry about padding for nested attribute.
// Because as long as all sub attributes have padding, the payload is aligned.
header->nla_len += append_data.size();
}
void NL80211NestedAttr::AddFlagAttribute(int attribute_id) {
// We only need to append a header for flag attribute.
// Make space for the new attribute.
data_.resize(data_.size() + NLA_HDRLEN, 0);
nlattr* flag_header =
reinterpret_cast<nlattr*>(data_.data() + data_.size() - NLA_HDRLEN);
flag_header->nla_type = attribute_id;
flag_header->nla_len = NLA_HDRLEN;
nlattr* nl_header = reinterpret_cast<nlattr*>(data_.data());
nl_header->nla_len += NLA_HDRLEN;
}
bool NL80211NestedAttr::HasAttribute(int id) const {
return BaseNL80211Attr::GetAttributeImpl(data_.data() + NLA_HDRLEN,
data_.size() - NLA_HDRLEN,
id, nullptr, nullptr);
}
bool NL80211NestedAttr::GetAttribute(int id,
NL80211NestedAttr* attribute) const {
uint8_t* start = nullptr;
uint8_t* end = nullptr;
if (!BaseNL80211Attr::GetAttributeImpl(data_.data() + NLA_HDRLEN,
data_.size() - NLA_HDRLEN,
id, &start, &end) ||
start == nullptr ||
end == nullptr) {
return false;
}
*attribute = NL80211NestedAttr(vector<uint8_t>(start, end));
if (!attribute->IsValid()) {
return false;
}
return true;
}
bool NL80211NestedAttr::GetListOfNestedAttributes(
vector<NL80211NestedAttr>* value) const {
const uint8_t* ptr = data_.data() + NLA_HDRLEN;
const uint8_t* end_ptr = data_.data() + data_.size();
vector<NL80211NestedAttr> nested_attr_list;
while (ptr + NLA_HDRLEN <= end_ptr) {
const nlattr* header = reinterpret_cast<const nlattr*>(ptr);
if (ptr + NLA_ALIGN(header->nla_len) > end_ptr) {
LOG(ERROR) << "Failed to get list of nested attributes: invalid nla_len.";
return false;
}
nested_attr_list.emplace_back(
NL80211NestedAttr(vector<uint8_t>(ptr,
ptr + NLA_ALIGN(header->nla_len))));
if (!nested_attr_list.back().IsValid()) {
return false;
}
ptr += NLA_ALIGN(header->nla_len);
}
*value = std::move(nested_attr_list);
return true;
}
void NL80211NestedAttr::DebugLog() const {
const uint8_t* ptr = data_.data() + NLA_HDRLEN;
const uint8_t* end_ptr = data_.data() + data_.size();
while (ptr + NLA_HDRLEN <= end_ptr) {
const nlattr* header = reinterpret_cast<const nlattr*>(ptr);
if (ptr + NLA_ALIGN(header->nla_len) > end_ptr) {
LOG(ERROR) << "broken nl80211 atrribute.";
return;
}
LOG(INFO) << "Have attribute with nla_type=" << header->nla_type
<< " and nla_len=" << header->nla_len;
if (header->nla_len == 0) {
LOG(ERROR) << "0 is a bad nla_len";
return;
}
ptr += NLA_ALIGN(header->nla_len);
}
}
} // namespace wificond
} // namespace android
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