Merge "Implement MessageMutator and FamilyTracker"
diff --git a/automotive/can/1.0/default/libnl++/Android.bp b/automotive/can/1.0/default/libnl++/Android.bp
index 90e1002..a69e302 100644
--- a/automotive/can/1.0/default/libnl++/Android.bp
+++ b/automotive/can/1.0/default/libnl++/Android.bp
@@ -22,6 +22,7 @@
"protocols/common/Empty.cpp",
"protocols/common/Error.cpp",
"protocols/generic/Ctrl.cpp",
+ "protocols/generic/FamilyTracker.cpp",
"protocols/generic/Generic.cpp",
"protocols/generic/GenericMessageBase.cpp",
"protocols/generic/Unknown.cpp",
@@ -34,6 +35,7 @@
"protocols/all.cpp",
"Attributes.cpp",
"MessageFactory.cpp",
+ "MessageMutator.cpp",
"Socket.cpp",
"common.cpp",
"printer.cpp",
diff --git a/automotive/can/1.0/default/libnl++/MessageMutator.cpp b/automotive/can/1.0/default/libnl++/MessageMutator.cpp
new file mode 100644
index 0000000..00b48a6
--- /dev/null
+++ b/automotive/can/1.0/default/libnl++/MessageMutator.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <libnl++/MessageMutator.h>
+
+namespace android::nl {
+
+MessageMutator::MessageMutator(nlmsghdr* buffer, size_t totalLen)
+ : mConstBuffer(buffer, totalLen), mMutableBuffer(buffer) {
+ CHECK(totalLen >= sizeof(nlmsghdr));
+}
+
+nlmsghdr* MessageMutator::operator->() const {
+ return mMutableBuffer;
+}
+
+MessageMutator::operator Buffer<nlmsghdr>() const {
+ return mConstBuffer;
+}
+
+uint64_t MessageMutator::read(Buffer<nlattr> attr) const {
+ return attr.data<uint64_t>().copyFirst();
+}
+
+void MessageMutator::write(Buffer<nlattr> attr, uint64_t val) const {
+ const auto attrData = attr.data<uint64_t>();
+ const auto offset = mConstBuffer.getOffset(attrData);
+ CHECK(offset.has_value()) << "Trying to write attribute that's not a member of this message";
+
+ const auto writeableBuffer = reinterpret_cast<uint8_t*>(mMutableBuffer) + *offset;
+ const auto attrSize = attrData.getRaw().len();
+
+ if (attrSize > sizeof(val)) memset(writeableBuffer, 0, attrSize);
+ memcpy(writeableBuffer, &val, std::min(sizeof(val), attrSize));
+}
+
+} // namespace android::nl
diff --git a/automotive/can/1.0/default/libnl++/include/libnl++/Attributes.h b/automotive/can/1.0/default/libnl++/include/libnl++/Attributes.h
index f16d997..a438a69 100644
--- a/automotive/can/1.0/default/libnl++/include/libnl++/Attributes.h
+++ b/automotive/can/1.0/default/libnl++/include/libnl++/Attributes.h
@@ -93,14 +93,29 @@
*/
template <typename T>
T get(nlattrtype_t attrtype) const {
- const auto& ind = index();
- const auto it = ind.find(attrtype);
- if (it == ind.end()) {
+ const auto buffer = getBuffer(attrtype);
+ if (!buffer.has_value()) {
LOG(WARNING) << "Netlink attribute is missing: " << attrtype;
return T{};
}
- return parse<T>(it->second);
+ return parse<T>(*buffer);
+ }
+
+ /**
+ * Fetches underlying buffer of a given attribute.
+ *
+ * This is a low-level access method unlikely to be useful in most cases. Please consider
+ * using #get instead.
+ *
+ * \param attrtype Attribute to fetch
+ * \return Attribute buffer.
+ */
+ std::optional<Buffer<nlattr>> getBuffer(nlattrtype_t attrtype) const {
+ const auto& ind = index();
+ const auto it = ind.find(attrtype);
+ if (it == ind.end()) return std::nullopt;
+ return it->second;
}
/**
diff --git a/automotive/can/1.0/default/libnl++/include/libnl++/Buffer.h b/automotive/can/1.0/default/libnl++/include/libnl++/Buffer.h
index bf83fbc..d759a0a 100644
--- a/automotive/can/1.0/default/libnl++/include/libnl++/Buffer.h
+++ b/automotive/can/1.0/default/libnl++/include/libnl++/Buffer.h
@@ -91,6 +91,18 @@
return {impl::data<const T, const D>(mData, offset), dataEnd()};
}
+ template <typename B>
+ std::optional<uintptr_t> getOffset(Buffer<B> inner) const {
+ const auto selfStart = uintptr_t(mData);
+ const auto selfEnd = uintptr_t(mBufferEnd);
+ const auto innerStart = uintptr_t(inner.mData);
+ const auto innerEnd = uintptr_t(inner.mBufferEnd);
+
+ if (innerStart < selfStart || innerEnd > selfEnd) return std::nullopt;
+
+ return innerStart - selfStart;
+ }
+
class iterator {
public:
iterator() : mCurrent(nullptr, size_t(0)) {
diff --git a/automotive/can/1.0/default/libnl++/include/libnl++/MessageMutator.h b/automotive/can/1.0/default/libnl++/include/libnl++/MessageMutator.h
new file mode 100644
index 0000000..7d495e9
--- /dev/null
+++ b/automotive/can/1.0/default/libnl++/include/libnl++/MessageMutator.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <libnl++/Message.h>
+
+namespace android::nl {
+
+/**
+ * In-place message mutator.
+ *
+ * Useful for making small changes (such as adjusting const-sized attributes or struct fields)
+ * efficiently and in-place. However, if you need to rebuild the message (e.g. to modify variable
+ * sized attributes or add/remove them), you need to use MessageFactory instead.
+ */
+class MessageMutator {
+ public:
+ /**
+ * Construct message mutator object from editable buffer.
+ */
+ MessageMutator(nlmsghdr* buffer, size_t totalLen);
+
+ nlmsghdr* operator->() const;
+ operator Buffer<nlmsghdr>() const;
+
+ /**
+ * Read current attribute value.
+ *
+ * \param Read-only attribute buffer.
+ * \returns Attribute value.
+ */
+ uint64_t read(Buffer<nlattr> attr) const;
+
+ /**
+ * Write new attribute value.
+ *
+ * \param Read-only attribute buffer.
+ * \param val New value to set.
+ */
+ void write(Buffer<nlattr> attr, uint64_t val) const;
+
+ private:
+ const Buffer<nlmsghdr> mConstBuffer;
+ nlmsghdr* mMutableBuffer;
+};
+
+} // namespace android::nl
diff --git a/automotive/can/1.0/default/libnl++/include/libnl++/generic/FamilyTracker.h b/automotive/can/1.0/default/libnl++/include/libnl++/generic/FamilyTracker.h
new file mode 100644
index 0000000..2530035
--- /dev/null
+++ b/automotive/can/1.0/default/libnl++/include/libnl++/generic/FamilyTracker.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <libnl++/Buffer.h>
+#include <libnl++/Message.h>
+
+#include <linux/genetlink.h>
+
+#include <optional>
+
+namespace android::nl::generic {
+
+/**
+ * Tracker of Netlink family ID registrations.
+ */
+class FamilyTracker {
+ public:
+ /**
+ * Try parsing NL80211 message.
+ *
+ * Proper parsing of NL80211 nessages requires prior parsing of control message for Generic
+ * Netlink protocol.
+ *
+ * \param msg Message to parse
+ * \returns Parsed NL80211 message or std::nullopt if it wasn't one
+ */
+ std::optional<Message<genlmsghdr>> parseNl80211(Buffer<nlmsghdr> msg);
+
+ private:
+ /* For efficiency, we use a single hardcoded family ID. However, if we supported multiple family
+ * types, this should probably be a map.
+ */
+ std::optional<uint16_t> mNl80211FamilyId;
+
+ /**
+ * Track Generic protocol messages.
+ *
+ * This method is looking for family registration messages.
+ *
+ * \param msg Message to track
+ * \returns True, if the message was a control message (regardless of carrying
+ * family info or not)
+ */
+ bool track(const Buffer<nlmsghdr>& msg);
+};
+
+} // namespace android::nl::generic
diff --git a/automotive/can/1.0/default/libnl++/protocols/generic/FamilyTracker.cpp b/automotive/can/1.0/default/libnl++/protocols/generic/FamilyTracker.cpp
new file mode 100644
index 0000000..900560e
--- /dev/null
+++ b/automotive/can/1.0/default/libnl++/protocols/generic/FamilyTracker.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <libnl++/generic/FamilyTracker.h>
+
+#include <android-base/logging.h>
+
+namespace android::nl::generic {
+
+bool FamilyTracker::track(const Buffer<nlmsghdr>& buffer) {
+ const auto msgMaybe = nl::Message<genlmsghdr>::parse(buffer, {GENL_ID_CTRL});
+ if (!msgMaybe.has_value()) return false;
+
+ const auto msg = *msgMaybe;
+ if (msg->cmd != CTRL_CMD_NEWFAMILY) return true;
+
+ const auto familyName = msg.attributes.get<std::string>(CTRL_ATTR_FAMILY_NAME);
+ const auto familyId = msg.attributes.get<uint16_t>(CTRL_ATTR_FAMILY_ID);
+
+ if (familyId < GENL_START_ALLOC) {
+ LOG(WARNING) << "Invalid family ID: " << familyId;
+ return true;
+ }
+
+ if (familyName == "nl80211") mNl80211FamilyId = familyId;
+
+ return true;
+}
+
+std::optional<Message<genlmsghdr>> FamilyTracker::parseNl80211(Buffer<nlmsghdr> msg) {
+ if (track(msg)) return std::nullopt;
+ if (!mNl80211FamilyId.has_value()) return std::nullopt;
+
+ return nl::Message<genlmsghdr>::parse(msg, {*mNl80211FamilyId});
+}
+
+} // namespace android::nl::generic