/*
* 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_packet.h"
#include <android-base/logging.h>
using std::make_unique;
using std::unique_ptr;
using std::vector;
namespace android {
namespace wificond {
NL80211Packet::NL80211Packet(const vector<uint8_t>& data)
: data_(data) {
data_ = data;
}
NL80211Packet::NL80211Packet(const NL80211Packet& packet) {
data_ = packet.data_;
LOG(WARNING) << "Copy constructor is only used for unit tests";
}
NL80211Packet::NL80211Packet(uint16_t type,
uint8_t command,
uint32_t sequence,
uint32_t pid) {
// Initialize the netlink header and generic netlink header.
// NLMSG_HDRLEN and GENL_HDRLEN already include the padding size.
data_.resize(NLMSG_HDRLEN + GENL_HDRLEN, 0);
// Initialize length field.
nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data());
nl_header->nlmsg_len = data_.size();
// Add NLM_F_REQUEST flag.
nl_header->nlmsg_flags = nl_header->nlmsg_flags | NLM_F_REQUEST;
nl_header->nlmsg_type = type;
nl_header->nlmsg_seq = sequence;
nl_header->nlmsg_pid = pid;
genlmsghdr* genl_header =
reinterpret_cast<genlmsghdr*>(data_.data() + NLMSG_HDRLEN);
genl_header->version = 1;
genl_header->cmd = command;
// genl_header->reserved is aready 0.
}
bool NL80211Packet::IsValid() const {
// Verify the size of packet.
if (data_.size() < NLMSG_HDRLEN) {
LOG(ERROR) << "Cannot retrieve netlink header.";
return false;
}
const nlmsghdr* nl_header = reinterpret_cast<const nlmsghdr*>(data_.data());
// If type < NLMSG_MIN_TYPE, this should be a reserved control message,
// which doesn't carry a generic netlink header.
if (GetMessageType() >= NLMSG_MIN_TYPE) {
if (data_.size() < NLMSG_HDRLEN + GENL_HDRLEN ||
nl_header->nlmsg_len < NLMSG_HDRLEN + GENL_HDRLEN) {
LOG(ERROR) << "Cannot retrieve generic netlink header.";
return false;
}
}
// If it is an ERROR message, it should be long enough to carry an extra error
// code field.
// Kernel uses int for this field.
if (GetMessageType() == NLMSG_ERROR) {
if (data_.size() < NLMSG_HDRLEN + sizeof(int) ||
nl_header->nlmsg_len < NLMSG_HDRLEN + sizeof(int)) {
LOG(ERROR) << "Broken error message.";
return false;
}
}
// Verify the netlink header.
if (data_.size() < nl_header->nlmsg_len ||
nl_header->nlmsg_len < sizeof(nlmsghdr)) {
LOG(ERROR) << "Discarding incomplete / invalid message.";
return false;
}
return true;
}
bool NL80211Packet::IsDump() const {
return GetFlags() & NLM_F_DUMP;
}
bool NL80211Packet::IsMulti() const {
return GetFlags() & NLM_F_MULTI;
}
uint8_t NL80211Packet::GetCommand() const {
const genlmsghdr* genl_header = reinterpret_cast<const genlmsghdr*>(
data_.data() + NLMSG_HDRLEN);
return genl_header->cmd;
}
uint16_t NL80211Packet::GetFlags() const {
const nlmsghdr* nl_header = reinterpret_cast<const nlmsghdr*>(data_.data());
return nl_header->nlmsg_flags;
}
uint16_t NL80211Packet::GetMessageType() const {
const nlmsghdr* nl_header = reinterpret_cast<const nlmsghdr*>(data_.data());
return nl_header->nlmsg_type;
}
uint32_t NL80211Packet::GetMessageSequence() const {
const nlmsghdr* nl_header = reinterpret_cast<const nlmsghdr*>(data_.data());
return nl_header->nlmsg_seq;
}
uint32_t NL80211Packet::GetPortId() const {
const nlmsghdr* nl_header = reinterpret_cast<const nlmsghdr*>(data_.data());
return nl_header->nlmsg_pid;
}
int NL80211Packet::GetErrorCode() const {
return -*reinterpret_cast<const int*>(data_.data() + NLMSG_HDRLEN);
}
const vector<uint8_t>& NL80211Packet::GetConstData() const {
return data_;
}
void NL80211Packet::SetCommand(uint8_t command) {
genlmsghdr* genl_header = reinterpret_cast<genlmsghdr*>(
data_.data() + NLMSG_HDRLEN);
genl_header->cmd = command;
}
void NL80211Packet::AddFlag(uint16_t flag) {
nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data());
nl_header->nlmsg_flags |= flag;
}
void NL80211Packet::SetFlags(uint16_t flags) {
nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data());
nl_header->nlmsg_flags = flags;
}
void NL80211Packet::SetMessageType(uint16_t message_type) {
nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data());
nl_header->nlmsg_type = message_type;
}
void NL80211Packet::SetMessageSequence(uint32_t message_sequence) {
nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data());
nl_header->nlmsg_seq = message_sequence;
}
void NL80211Packet::SetPortId(uint32_t pid) {
nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data());
nl_header->nlmsg_pid = pid;
}
void NL80211Packet::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());
nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data());
// We don't need to worry about padding for a nl80211 packet.
// Because as long as all sub attributes have padding, the payload is aligned.
nl_header->nlmsg_len += append_data.size();
}
void NL80211Packet::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;
nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data());
nl_header->nlmsg_len += NLA_HDRLEN;
}
bool NL80211Packet::HasAttribute(int id) const {
return BaseNL80211Attr::GetAttributeImpl(
data_.data() + NLMSG_HDRLEN + GENL_HDRLEN,
data_.size() - NLMSG_HDRLEN - GENL_HDRLEN,
id, nullptr, nullptr);
}
bool NL80211Packet::GetAttribute(int id,
NL80211NestedAttr* attribute) const {
uint8_t* start = nullptr;
uint8_t* end = nullptr;
if (!BaseNL80211Attr::GetAttributeImpl(
data_.data() + NLMSG_HDRLEN + GENL_HDRLEN,
data_.size() - NLMSG_HDRLEN - GENL_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 NL80211Packet::GetAllAttributes(
vector<BaseNL80211Attr>* attributes) const {
const uint8_t* ptr = data_.data() + NLMSG_HDRLEN + GENL_HDRLEN;
const uint8_t* end_ptr = data_.data() + data_.size();
while (ptr + NLA_HDRLEN <= end_ptr) {
auto header = reinterpret_cast<const nlattr*>(ptr);
if (ptr + NLA_ALIGN(header->nla_len) > end_ptr ||
header->nla_len == 0) {
LOG(ERROR) << "broken nl80211 atrribute.";
return false;
}
attributes->emplace_back(
header->nla_type,
vector<uint8_t>(ptr + NLA_HDRLEN, ptr + header->nla_len));
ptr += NLA_ALIGN(header->nla_len);
}
return true;
}
void NL80211Packet::DebugLog() const {
const uint8_t* ptr = data_.data() + NLMSG_HDRLEN + GENL_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