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
17 #include "netlinkmessage.h"
18
19 #include "log.h"
20
21 #include <linux/netlink.h>
22 #include <linux/rtnetlink.h>
23 #include <sys/types.h>
24 #include <unistd.h>
25 #include <netlink/msg.h>
26
getSpaceForMessageType(uint16_t type)27 size_t getSpaceForMessageType(uint16_t type) {
28 switch (type) {
29 case RTM_NEWLINK:
30 case RTM_GETLINK:
31 return NLMSG_SPACE(sizeof(ifinfomsg));
32 default:
33 return 0;
34 }
35 }
36
NetlinkMessage(uint16_t type,uint32_t sequence)37 NetlinkMessage::NetlinkMessage(uint16_t type,
38 uint32_t sequence)
39 : mData(getSpaceForMessageType(type), 0) {
40
41 auto header = reinterpret_cast<nlmsghdr*>(mData.data());
42 header->nlmsg_len = mData.size();
43 header->nlmsg_flags = NLM_F_REQUEST;
44 header->nlmsg_type = type;
45 header->nlmsg_seq = sequence;
46 header->nlmsg_pid = getpid();
47 }
48
NetlinkMessage(const char * data,size_t size)49 NetlinkMessage::NetlinkMessage(const char* data, size_t size)
50 : mData(data, data + size) {
51 }
52
getAttribute(int attributeId,void * data,size_t size) const53 bool NetlinkMessage::getAttribute(int attributeId, void* data, size_t size) const {
54 const void* value = nullptr;
55 const auto attr = nlmsg_find_attr((struct nlmsghdr*)mData.data(), sizeof(ifinfomsg), attributeId);
56 if (!attr) {
57 return false;
58 }
59 value = (const uint8_t*) attr + NLA_HDRLEN;
60 size = attr->nla_len;
61 memcpy(data, value, size);
62 return true;
63 }
64
type() const65 uint16_t NetlinkMessage::type() const {
66 auto header = reinterpret_cast<const nlmsghdr*>(mData.data());
67 return header->nlmsg_type;
68 }
69
sequence() const70 uint32_t NetlinkMessage::sequence() const {
71 auto header = reinterpret_cast<const nlmsghdr*>(mData.data());
72 return header->nlmsg_seq;
73 }
74