Davide Pesavento | 50b9226 | 2018-07-11 12:28:31 -0400 | [diff] [blame] | 1 | /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */ |
| 2 | /* |
| 3 | * Copyright (c) 2013-2018 Regents of the University of California. |
| 4 | * |
| 5 | * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions). |
| 6 | * |
| 7 | * ndn-cxx library is free software: you can redistribute it and/or modify it under the |
| 8 | * terms of the GNU Lesser General Public License as published by the Free Software |
| 9 | * Foundation, either version 3 of the License, or (at your option) any later version. |
| 10 | * |
| 11 | * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY |
| 12 | * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A |
| 13 | * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. |
| 14 | * |
| 15 | * You should have received copies of the GNU General Public License and GNU Lesser |
| 16 | * General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see |
| 17 | * <http://www.gnu.org/licenses/>. |
| 18 | * |
| 19 | * See AUTHORS.md for complete list of ndn-cxx authors and contributors. |
| 20 | * |
| 21 | * @author Davide Pesavento <davide.pesavento@lip6.fr> |
| 22 | */ |
| 23 | |
Davide Pesavento | a0b2a2c | 2018-07-19 01:01:06 -0400 | [diff] [blame] | 24 | #ifndef NDN_NET_NETLINK_MESSAGE_HPP |
| 25 | #define NDN_NET_NETLINK_MESSAGE_HPP |
Davide Pesavento | 50b9226 | 2018-07-11 12:28:31 -0400 | [diff] [blame] | 26 | |
| 27 | #include "../../common.hpp" |
| 28 | #include "../ethernet.hpp" |
| 29 | |
Davide Pesavento | 474c3b2 | 2018-08-25 16:24:43 -0400 | [diff] [blame] | 30 | #ifndef NDN_CXX_HAVE_NETLINK |
Davide Pesavento | 50b9226 | 2018-07-11 12:28:31 -0400 | [diff] [blame] | 31 | #error "This file should not be included ..." |
| 32 | #endif |
| 33 | |
| 34 | #include <linux/netlink.h> |
| 35 | #include <linux/rtnetlink.h> |
| 36 | #include <string.h> |
| 37 | |
| 38 | #include <cstring> |
| 39 | #include <map> |
| 40 | |
| 41 | #include <boost/asio/ip/address.hpp> |
| 42 | |
| 43 | namespace ndn { |
| 44 | namespace net { |
| 45 | |
| 46 | template<typename T> |
| 47 | constexpr size_t |
| 48 | getAttributeLength(const T* attr); |
| 49 | |
| 50 | template<> |
| 51 | constexpr size_t |
| 52 | getAttributeLength(const nlattr* attr) |
| 53 | { |
| 54 | return attr->nla_len; |
| 55 | } |
| 56 | |
| 57 | template<> |
| 58 | constexpr size_t |
| 59 | getAttributeLength(const rtattr* attr) |
| 60 | { |
| 61 | return attr->rta_len; |
| 62 | } |
| 63 | |
| 64 | template<typename T> |
| 65 | constexpr size_t |
| 66 | getAttributeLengthAligned(const T* attr); |
| 67 | |
| 68 | template<> |
| 69 | constexpr size_t |
| 70 | getAttributeLengthAligned(const nlattr* attr) |
| 71 | { |
| 72 | return NLA_ALIGN(attr->nla_len); |
| 73 | } |
| 74 | |
| 75 | template<> |
| 76 | constexpr size_t |
| 77 | getAttributeLengthAligned(const rtattr* attr) |
| 78 | { |
| 79 | return RTA_ALIGN(attr->rta_len); |
| 80 | } |
| 81 | |
| 82 | template<typename T> |
| 83 | constexpr uint16_t |
| 84 | getAttributeType(const T* attr); |
| 85 | |
| 86 | template<> |
| 87 | constexpr uint16_t |
| 88 | getAttributeType(const nlattr* attr) |
| 89 | { |
| 90 | return attr->nla_type & NLA_TYPE_MASK; |
| 91 | } |
| 92 | |
| 93 | template<> |
| 94 | constexpr uint16_t |
| 95 | getAttributeType(const rtattr* attr) |
| 96 | { |
| 97 | return attr->rta_type; |
| 98 | } |
| 99 | |
| 100 | template<typename T> |
| 101 | const uint8_t* |
| 102 | getAttributeValue(const T* attr); |
| 103 | |
| 104 | template<> |
| 105 | inline const uint8_t* |
| 106 | getAttributeValue(const nlattr* attr) |
| 107 | { |
| 108 | return reinterpret_cast<const uint8_t*>(attr) + NLA_HDRLEN; |
| 109 | } |
| 110 | |
| 111 | template<> |
| 112 | inline const uint8_t* |
| 113 | getAttributeValue(const rtattr* attr) |
| 114 | { |
| 115 | return reinterpret_cast<const uint8_t*>(RTA_DATA(const_cast<rtattr*>(attr))); |
| 116 | } |
| 117 | |
| 118 | template<typename T> |
| 119 | constexpr size_t |
| 120 | getAttributeValueLength(const T* attr); |
| 121 | |
| 122 | template<> |
| 123 | constexpr size_t |
| 124 | getAttributeValueLength(const nlattr* attr) |
| 125 | { |
| 126 | return attr->nla_len - NLA_HDRLEN; |
| 127 | } |
| 128 | |
| 129 | template<> |
| 130 | constexpr size_t |
| 131 | getAttributeValueLength(const rtattr* attr) |
| 132 | { |
| 133 | return RTA_PAYLOAD(attr); |
| 134 | } |
| 135 | |
| 136 | template<typename T> |
| 137 | class NetlinkMessageAttributes; |
| 138 | |
| 139 | class NetlinkMessage |
| 140 | { |
| 141 | public: |
| 142 | explicit |
| 143 | NetlinkMessage(const uint8_t* buf, size_t buflen) noexcept |
| 144 | : m_msg(reinterpret_cast<const nlmsghdr*>(buf)) |
| 145 | , m_length(buflen) |
| 146 | { |
| 147 | BOOST_ASSERT(buf != nullptr); |
| 148 | } |
| 149 | |
| 150 | const nlmsghdr& |
| 151 | operator*() const noexcept |
| 152 | { |
| 153 | return *m_msg; |
| 154 | } |
| 155 | |
| 156 | const nlmsghdr* |
| 157 | operator->() const noexcept |
| 158 | { |
| 159 | return m_msg; |
| 160 | } |
| 161 | |
| 162 | bool |
| 163 | isValid() const noexcept |
| 164 | { |
| 165 | return NLMSG_OK(m_msg, m_length); |
| 166 | } |
| 167 | |
| 168 | NetlinkMessage |
| 169 | getNext() const noexcept |
| 170 | { |
| 171 | BOOST_ASSERT(isValid()); |
| 172 | |
| 173 | // mimic NLMSG_NEXT |
| 174 | auto thisLen = NLMSG_ALIGN(m_msg->nlmsg_len); |
| 175 | return NetlinkMessage{reinterpret_cast<const uint8_t*>(m_msg) + thisLen, m_length - thisLen}; |
| 176 | } |
| 177 | |
| 178 | template<typename T> |
| 179 | const T* |
| 180 | getPayload() const noexcept |
| 181 | { |
| 182 | BOOST_ASSERT(isValid()); |
| 183 | |
| 184 | if (m_msg->nlmsg_len < NLMSG_LENGTH(sizeof(T))) |
| 185 | return nullptr; |
| 186 | |
| 187 | return reinterpret_cast<const T*>(NLMSG_DATA(const_cast<nlmsghdr*>(m_msg))); |
| 188 | } |
| 189 | |
| 190 | template<typename AttributeT, typename PayloadT> |
| 191 | NetlinkMessageAttributes<AttributeT> |
| 192 | getAttributes(const PayloadT* p) const noexcept |
| 193 | { |
| 194 | BOOST_ASSERT(isValid()); |
| 195 | |
| 196 | auto begin = reinterpret_cast<const uint8_t*>(p) + NLMSG_ALIGN(sizeof(PayloadT)); |
| 197 | auto length = NLMSG_PAYLOAD(m_msg, sizeof(PayloadT)); |
| 198 | return NetlinkMessageAttributes<AttributeT>{reinterpret_cast<const AttributeT*>(begin), length}; |
| 199 | } |
| 200 | |
| 201 | private: |
| 202 | const nlmsghdr* m_msg; |
| 203 | size_t m_length; |
| 204 | }; |
| 205 | |
| 206 | template<typename T> |
| 207 | class NetlinkMessageAttributes |
| 208 | { |
| 209 | // empty type used to implement tag dispatching in getAttributeByType() |
| 210 | template<typename U> |
| 211 | struct AttrValueTypeTag {}; |
| 212 | |
| 213 | public: |
| 214 | explicit |
| 215 | NetlinkMessageAttributes(const T* begin, size_t length) noexcept |
| 216 | { |
| 217 | for (; isAttrValid(begin, length); begin = getNextAttr(begin, length)) { |
| 218 | m_attrs[getAttributeType(begin)] = begin; |
| 219 | } |
| 220 | } |
| 221 | |
| 222 | size_t |
| 223 | size() const noexcept |
| 224 | { |
| 225 | return m_attrs.size(); |
| 226 | } |
| 227 | |
| 228 | template<typename U> |
| 229 | optional<U> |
| 230 | getAttributeByType(uint16_t attrType) const |
| 231 | { |
| 232 | auto it = m_attrs.find(attrType); |
| 233 | if (it == m_attrs.end()) |
| 234 | return nullopt; |
| 235 | |
| 236 | return convertAttrValue(getAttributeValue(it->second), |
| 237 | getAttributeValueLength(it->second), |
| 238 | AttrValueTypeTag<U>{}); |
| 239 | } |
| 240 | |
| 241 | private: |
| 242 | static bool |
| 243 | isAttrValid(const T* attr, size_t nBytesRemaining) noexcept |
| 244 | { |
| 245 | return attr != nullptr && |
| 246 | nBytesRemaining >= sizeof(T) && |
| 247 | getAttributeLength(attr) >= sizeof(T) && |
| 248 | getAttributeLength(attr) <= nBytesRemaining; |
| 249 | } |
| 250 | |
| 251 | static const T* |
| 252 | getNextAttr(const T* attr, size_t& nBytesRemaining) noexcept |
| 253 | { |
| 254 | auto len = getAttributeLengthAligned(attr); |
| 255 | if (len > nBytesRemaining) // prevent integer underflow |
| 256 | return nullptr; |
| 257 | |
| 258 | nBytesRemaining -= len; |
| 259 | return reinterpret_cast<const T*>(reinterpret_cast<const uint8_t*>(attr) + len); |
| 260 | } |
| 261 | |
| 262 | template<typename Integral> |
| 263 | static std::enable_if_t<std::is_integral<Integral>::value, optional<Integral>> |
| 264 | convertAttrValue(const uint8_t* val, size_t len, AttrValueTypeTag<Integral>) |
| 265 | { |
| 266 | if (len < sizeof(Integral)) |
| 267 | return nullopt; |
| 268 | |
| 269 | Integral i; |
| 270 | std::memcpy(&i, val, sizeof(Integral)); |
| 271 | return i; |
| 272 | } |
| 273 | |
| 274 | static optional<std::string> |
| 275 | convertAttrValue(const uint8_t* val, size_t len, AttrValueTypeTag<std::string>) |
| 276 | { |
| 277 | auto str = reinterpret_cast<const char*>(val); |
| 278 | if (::strnlen(str, len) < len) |
| 279 | return std::string(str); |
| 280 | else |
| 281 | return nullopt; |
| 282 | } |
| 283 | |
| 284 | static optional<ethernet::Address> |
| 285 | convertAttrValue(const uint8_t* val, size_t len, AttrValueTypeTag<ethernet::Address>) |
| 286 | { |
| 287 | if (len < ethernet::ADDR_LEN) |
| 288 | return nullopt; |
| 289 | |
| 290 | return ethernet::Address(val); |
| 291 | } |
| 292 | |
| 293 | template<typename IpAddress> |
| 294 | static std::enable_if_t<std::is_same<IpAddress, boost::asio::ip::address_v4>::value || |
| 295 | std::is_same<IpAddress, boost::asio::ip::address_v6>::value, optional<IpAddress>> |
| 296 | convertAttrValue(const uint8_t* val, size_t len, AttrValueTypeTag<IpAddress>) |
| 297 | { |
| 298 | typename IpAddress::bytes_type bytes; |
| 299 | if (len < bytes.size()) |
| 300 | return nullopt; |
| 301 | |
| 302 | std::copy_n(val, bytes.size(), bytes.begin()); |
| 303 | return IpAddress(bytes); |
| 304 | } |
| 305 | |
| 306 | private: |
| 307 | std::map<uint16_t, const T*> m_attrs; |
| 308 | }; |
| 309 | |
Davide Pesavento | 50b9226 | 2018-07-11 12:28:31 -0400 | [diff] [blame] | 310 | } // namespace net |
| 311 | } // namespace ndn |
| 312 | |
Davide Pesavento | a0b2a2c | 2018-07-19 01:01:06 -0400 | [diff] [blame] | 313 | #endif // NDN_NET_NETLINK_MESSAGE_HPP |