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 <libnl++/MessageFactory.h>
18
19 #include <android-base/logging.h>
20 #include <libnl++/bits.h>
21
22 namespace android::nl {
23
tail(nlmsghdr * msg)24 static nlattr* tail(nlmsghdr* msg) {
25 return reinterpret_cast<nlattr*>(uintptr_t(msg) + impl::align(msg->nlmsg_len));
26 }
27
add(nlmsghdr * msg,size_t maxLen,nlattrtype_t type,const void * data,size_t dataLen)28 nlattr* MessageFactoryBase::add(nlmsghdr* msg, size_t maxLen, nlattrtype_t type, const void* data,
29 size_t dataLen) {
30 const auto totalAttrLen = impl::length<nlattr>(dataLen);
31 const auto newLen = impl::align(msg->nlmsg_len) + impl::align(totalAttrLen);
32 if (newLen > maxLen) {
33 LOG(ERROR) << "Can't add attribute of size " << dataLen //
34 << " - exceeded maxLen: " << newLen << " > " << maxLen;
35 return nullptr;
36 }
37
38 auto attr = tail(msg);
39 attr->nla_len = totalAttrLen;
40 attr->nla_type = type;
41 if (dataLen > 0) memcpy(impl::data<nlattr, void>(attr), data, dataLen);
42
43 msg->nlmsg_len = newLen;
44 return attr;
45 }
46
closeNested(nlmsghdr * msg,nlattr * nested)47 void MessageFactoryBase::closeNested(nlmsghdr* msg, nlattr* nested) {
48 if (nested == nullptr) return;
49 nested->nla_len = uintptr_t(tail(msg)) - uintptr_t(nested);
50 }
51
52 } // namespace android::nl
53