1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "wificond/net/nl80211_packet.h" 18 19 #include <android-base/logging.h> 20 21 using std::vector; 22 23 namespace android { 24 namespace wificond { 25 26 NL80211Packet::NL80211Packet(const vector<uint8_t>& data) 27 : data_(data) { 28 data_ = data; 29 } 30 31 NL80211Packet::NL80211Packet(const NL80211Packet& packet) { 32 data_ = packet.data_; 33 LOG(WARNING) << "Copy constructor is only used for unit tests"; 34 } 35 36 NL80211Packet::NL80211Packet(uint16_t type, 37 uint8_t command, 38 uint32_t sequence, 39 uint32_t pid) { 40 // Initialize the netlink header and generic netlink header. 41 // NLMSG_HDRLEN and GENL_HDRLEN already include the padding size. 42 data_.resize(NLMSG_HDRLEN + GENL_HDRLEN, 0); 43 // Initialize length field. 44 nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data()); 45 nl_header->nlmsg_len = data_.size(); 46 // Add NLM_F_REQUEST flag. 47 nl_header->nlmsg_flags = nl_header->nlmsg_flags | NLM_F_REQUEST; 48 nl_header->nlmsg_type = type; 49 nl_header->nlmsg_seq = sequence; 50 nl_header->nlmsg_pid = pid; 51 52 genlmsghdr* genl_header = 53 reinterpret_cast<genlmsghdr*>(data_.data() + NLMSG_HDRLEN); 54 genl_header->version = 1; 55 genl_header->cmd = command; 56 // genl_header->reserved is aready 0. 57 } 58 59 bool NL80211Packet::IsValid() const { 60 // Verify the size of packet. 61 if (data_.size() < NLMSG_HDRLEN) { 62 LOG(ERROR) << "Cannot retrieve netlink header."; 63 return false; 64 } 65 66 const nlmsghdr* nl_header = reinterpret_cast<const nlmsghdr*>(data_.data()); 67 68 // If type < NLMSG_MIN_TYPE, this should be a reserved control message, 69 // which doesn't carry a generic netlink header. 70 if (GetMessageType() >= NLMSG_MIN_TYPE) { 71 if (data_.size() < NLMSG_HDRLEN + GENL_HDRLEN || 72 nl_header->nlmsg_len < NLMSG_HDRLEN + GENL_HDRLEN) { 73 LOG(ERROR) << "Cannot retrieve generic netlink header."; 74 return false; 75 } 76 } 77 // If it is an ERROR message, it should be long enough to carry an extra error 78 // code field. 79 // Kernel uses int for this field. 80 if (GetMessageType() == NLMSG_ERROR) { 81 if (data_.size() < NLMSG_HDRLEN + sizeof(int) || 82 nl_header->nlmsg_len < NLMSG_HDRLEN + sizeof(int)) { 83 LOG(ERROR) << "Broken error message."; 84 return false; 85 } 86 } 87 88 // Verify the netlink header. 89 if (data_.size() < nl_header->nlmsg_len || 90 nl_header->nlmsg_len < sizeof(nlmsghdr)) { 91 LOG(ERROR) << "Discarding incomplete / invalid message."; 92 return false; 93 } 94 return true; 95 } 96 97 bool NL80211Packet::IsDump() const { 98 return GetFlags() & NLM_F_DUMP; 99 } 100 101 bool NL80211Packet::IsMulti() const { 102 return GetFlags() & NLM_F_MULTI; 103 } 104 105 uint8_t NL80211Packet::GetCommand() const { 106 const genlmsghdr* genl_header = reinterpret_cast<const genlmsghdr*>( 107 data_.data() + NLMSG_HDRLEN); 108 return genl_header->cmd; 109 } 110 111 uint16_t NL80211Packet::GetFlags() const { 112 const nlmsghdr* nl_header = reinterpret_cast<const nlmsghdr*>(data_.data()); 113 return nl_header->nlmsg_flags; 114 } 115 116 uint16_t NL80211Packet::GetMessageType() const { 117 const nlmsghdr* nl_header = reinterpret_cast<const nlmsghdr*>(data_.data()); 118 return nl_header->nlmsg_type; 119 } 120 121 uint32_t NL80211Packet::GetMessageSequence() const { 122 const nlmsghdr* nl_header = reinterpret_cast<const nlmsghdr*>(data_.data()); 123 return nl_header->nlmsg_seq; 124 } 125 126 uint32_t NL80211Packet::GetPortId() const { 127 const nlmsghdr* nl_header = reinterpret_cast<const nlmsghdr*>(data_.data()); 128 return nl_header->nlmsg_pid; 129 } 130 131 int NL80211Packet::GetErrorCode() const { 132 return -*reinterpret_cast<const int*>(data_.data() + NLMSG_HDRLEN); 133 } 134 135 const vector<uint8_t>& NL80211Packet::GetConstData() const { 136 return data_; 137 } 138 139 void NL80211Packet::SetCommand(uint8_t command) { 140 genlmsghdr* genl_header = reinterpret_cast<genlmsghdr*>( 141 data_.data() + NLMSG_HDRLEN); 142 genl_header->cmd = command; 143 } 144 145 void NL80211Packet::AddFlag(uint16_t flag) { 146 nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data()); 147 nl_header->nlmsg_flags |= flag; 148 } 149 150 void NL80211Packet::SetFlags(uint16_t flags) { 151 nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data()); 152 nl_header->nlmsg_flags = flags; 153 } 154 155 void NL80211Packet::SetMessageType(uint16_t message_type) { 156 nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data()); 157 nl_header->nlmsg_type = message_type; 158 } 159 160 void NL80211Packet::SetMessageSequence(uint32_t message_sequence) { 161 nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data()); 162 nl_header->nlmsg_seq = message_sequence; 163 } 164 165 void NL80211Packet::SetPortId(uint32_t pid) { 166 nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data()); 167 nl_header->nlmsg_pid = pid; 168 } 169 170 void NL80211Packet::AddAttribute(const BaseNL80211Attr& attribute) { 171 const vector<uint8_t>& append_data = attribute.GetConstData(); 172 // Append the data of |attribute| to |this|. 173 data_.insert(data_.end(), append_data.begin(), append_data.end()); 174 nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data()); 175 // We don't need to worry about padding for a nl80211 packet. 176 // Because as long as all sub attributes have padding, the payload is aligned. 177 nl_header->nlmsg_len += append_data.size(); 178 } 179 180 void NL80211Packet::AddFlagAttribute(int attribute_id) { 181 // We only need to append a header for flag attribute. 182 // Make space for the new attribute. 183 data_.resize(data_.size() + NLA_HDRLEN, 0); 184 nlattr* flag_header = 185 reinterpret_cast<nlattr*>(data_.data() + data_.size() - NLA_HDRLEN); 186 flag_header->nla_type = attribute_id; 187 flag_header->nla_len = NLA_HDRLEN; 188 nlmsghdr* nl_header = reinterpret_cast<nlmsghdr*>(data_.data()); 189 nl_header->nlmsg_len += NLA_HDRLEN; 190 } 191 192 bool NL80211Packet::HasAttribute(int id) const { 193 return BaseNL80211Attr::GetAttributeImpl( 194 data_.data() + NLMSG_HDRLEN + GENL_HDRLEN, 195 data_.size() - NLMSG_HDRLEN - GENL_HDRLEN, 196 id, nullptr, nullptr); 197 } 198 199 bool NL80211Packet::GetAttribute(int id, 200 NL80211NestedAttr* attribute) const { 201 uint8_t* start = nullptr; 202 uint8_t* end = nullptr; 203 if (!BaseNL80211Attr::GetAttributeImpl( 204 data_.data() + NLMSG_HDRLEN + GENL_HDRLEN, 205 data_.size() - NLMSG_HDRLEN - GENL_HDRLEN, 206 id, &start, &end) || 207 start == nullptr || 208 end == nullptr) { 209 return false; 210 } 211 *attribute = NL80211NestedAttr(vector<uint8_t>(start, end)); 212 if (!attribute->IsValid()) { 213 return false; 214 } 215 return true; 216 } 217 218 void NL80211Packet::DebugLog() const { 219 const uint8_t* ptr = data_.data() + NLMSG_HDRLEN + GENL_HDRLEN; 220 const uint8_t* end_ptr = data_.data() + data_.size(); 221 while (ptr + NLA_HDRLEN <= end_ptr) { 222 const nlattr* header = reinterpret_cast<const nlattr*>(ptr); 223 if (ptr + NLA_ALIGN(header->nla_len) > end_ptr) { 224 LOG(ERROR) << "broken nl80211 atrribute."; 225 return; 226 } 227 LOG(INFO) << "Have attribute with nla_type=" << header->nla_type 228 << " and nla_len=" << header->nla_len; 229 if (header->nla_len == 0) { 230 LOG(ERROR) << "0 is a bad nla_len"; 231 return; 232 } 233 ptr += NLA_ALIGN(header->nla_len); 234 } 235 } 236 237 } // namespace wificond 238 } // namespace android 239
