1 /* 2 * Copyright (C) 2017 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 #ifndef COMMON_LIBS_NET_NETLINK_REQUEST_H_ 17 #define COMMON_LIBS_NET_NETLINK_REQUEST_H_ 18 19 #include <stddef.h> 20 21 #include <linux/netlink.h> 22 23 #include <array> 24 #include <cstdint> 25 #include <string> 26 #include <type_traits> 27 #include <utility> 28 #include <vector> 29 30 namespace cuttlefish { 31 // Abstraction of Network link request. 32 // Used to supply kernel with information about which interface needs to be 33 // changed, and how. 34 class NetlinkRequest { 35 public: 36 // Create new Netlink Request structure. 37 // Parameter |type| specifies netlink request type (eg. RTM_NEWLINK), while 38 // |flags| are netlink and request specific flags (eg. NLM_F_DUMP). 39 NetlinkRequest(int type, int flags); 40 NetlinkRequest(NetlinkRequest&& other); 41 42 ~NetlinkRequest() = default; 43 44 // Add an IFLA tag followed by a string. 45 // Returns true, if successful. 46 void AddString(uint16_t type, const std::string& value); 47 48 // Add an IFLA tag followed by an integer. 49 template <typename T> AddInt(uint16_t type,T value)50 void AddInt(uint16_t type, T value) { 51 static_assert(std::is_integral<T>::value, 52 "AddInt must be used on integer types."); 53 AppendTag(type, &value, sizeof(value)); 54 } 55 56 // Add an interface info structure. 57 // Parameter |if_index| specifies particular interface index to which the 58 // attributes following the IfInfo apply. 59 void AddIfInfo(int32_t if_index, bool is_operational); 60 61 // Add an address info to a specific interface. 62 void AddAddrInfo(int32_t if_index, int prefix_len = 24); 63 64 // Add an ethernet address/mac address 65 void AddMacAddress(const std::array<unsigned char, 6>& address); 66 67 // Creates new list. 68 // List mimic recursive structures in a flat, continuous representation. 69 // Each call to PushList() should have a corresponding call to PopList 70 // indicating end of sub-attribute list. 71 void PushList(uint16_t type); 72 73 // Indicates end of previously declared list. 74 void PopList(); 75 76 // Request data. 77 void* RequestData() const; 78 79 // Request length. 80 size_t RequestLength() const; 81 82 // Request Sequence Number. 83 uint32_t SeqNo() const; 84 85 // Append raw data to buffer. 86 // data must not be null. 87 // Returns pointer to copied location. 88 void* AppendRaw(const void* data, size_t length); 89 90 // Reserve |length| number of bytes in the buffer. 91 // Returns pointer to reserved location. 92 void* ReserveRaw(size_t length); 93 94 // Append specialized data. Append(const T & data)95 template <typename T> T* Append(const T& data) { 96 return static_cast<T*>(AppendRaw(&data, sizeof(T))); 97 } 98 99 // Reserve specialized data. Reserve()100 template <typename T> T* Reserve() { 101 return static_cast<T*>(ReserveRaw(sizeof(T))); 102 } 103 104 private: 105 nlattr* AppendTag(uint16_t type, const void* data, uint16_t length); 106 107 std::vector<std::pair<nlattr*, int32_t>> lists_; 108 std::vector<char> request_; 109 nlmsghdr* header_; 110 111 NetlinkRequest(const NetlinkRequest&) = delete; 112 NetlinkRequest& operator= (const NetlinkRequest&) = delete; 113 }; 114 } // namespace cuttlefish 115 #endif // COMMON_LIBS_NET_NETLINK_REQUEST_H_ 116