1 /*
2 * Copyright (C) 2019 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 "NetlinkRequest.h"
18
19 #include <android-base/logging.h>
20
21 namespace android::netdevice::impl {
22
nlmsg_tail(struct nlmsghdr * n)23 static struct rtattr* nlmsg_tail(struct nlmsghdr* n) {
24 return reinterpret_cast<struct rtattr*>( //
25 reinterpret_cast<uintptr_t>(n) + NLMSG_ALIGN(n->nlmsg_len));
26 }
27
addattr_l(struct nlmsghdr * n,size_t maxLen,rtattrtype_t type,const void * data,size_t dataLen)28 struct rtattr* addattr_l(struct nlmsghdr* n, size_t maxLen, rtattrtype_t type, const void* data,
29 size_t dataLen) {
30 size_t newLen = NLMSG_ALIGN(n->nlmsg_len) + RTA_SPACE(dataLen);
31 if (newLen > maxLen) {
32 LOG(ERROR) << "addattr_l failed - exceeded maxLen: " << newLen << " > " << maxLen;
33 return nullptr;
34 }
35
36 auto attr = nlmsg_tail(n);
37 attr->rta_len = RTA_SPACE(dataLen);
38 attr->rta_type = type;
39 if (dataLen > 0) memcpy(RTA_DATA(attr), data, dataLen);
40
41 n->nlmsg_len = newLen;
42 return attr;
43 }
44
addattr_nest(struct nlmsghdr * n,size_t maxLen,rtattrtype_t type)45 struct rtattr* addattr_nest(struct nlmsghdr* n, size_t maxLen, rtattrtype_t type) {
46 return addattr_l(n, maxLen, type, nullptr, 0);
47 }
48
addattr_nest_end(struct nlmsghdr * n,struct rtattr * nest)49 void addattr_nest_end(struct nlmsghdr* n, struct rtattr* nest) {
50 size_t nestLen = reinterpret_cast<uintptr_t>(nlmsg_tail(n)) - reinterpret_cast<uintptr_t>(nest);
51 nest->rta_len = nestLen;
52 }
53
54 } // namespace android::netdevice::impl
55