Default implementation for CAN bus HAL
This implementation supports SocketCAN interfaces.
Bug: 135918744
Test: VTS (separate new change)
Change-Id: I12b93e37fa64e341bee2c64eaf130b39977fcef5
diff --git a/automotive/can/1.0/default/libnetdevice/NetlinkSocket.cpp b/automotive/can/1.0/default/libnetdevice/NetlinkSocket.cpp
new file mode 100644
index 0000000..0514764
--- /dev/null
+++ b/automotive/can/1.0/default/libnetdevice/NetlinkSocket.cpp
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2019 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 "NetlinkSocket.h"
+
+#include <android-base/logging.h>
+
+namespace android {
+namespace netdevice {
+
+NetlinkSocket::NetlinkSocket(int protocol) {
+ mFd.reset(socket(AF_NETLINK, SOCK_RAW, protocol));
+ if (!mFd.ok()) {
+ LOG(ERROR) << "Can't open Netlink socket: " << errno;
+ mFailed = true;
+ return;
+ }
+
+ struct sockaddr_nl sa = {};
+ sa.nl_family = AF_NETLINK;
+
+ if (bind(mFd.get(), reinterpret_cast<struct sockaddr*>(&sa), sizeof(sa)) < 0) {
+ LOG(ERROR) << "Can't bind Netlink socket: " << errno;
+ mFd.reset();
+ mFailed = true;
+ }
+}
+
+bool NetlinkSocket::send(struct nlmsghdr* nlmsg) {
+ if (mFailed) return false;
+
+ nlmsg->nlmsg_pid = 0; // kernel
+ nlmsg->nlmsg_seq = mSeq++;
+ nlmsg->nlmsg_flags |= NLM_F_ACK;
+
+ struct iovec iov = {nlmsg, nlmsg->nlmsg_len};
+
+ struct sockaddr_nl sa = {};
+ sa.nl_family = AF_NETLINK;
+
+ struct msghdr msg = {};
+ msg.msg_name = &sa;
+ msg.msg_namelen = sizeof(sa);
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+
+ if (sendmsg(mFd.get(), &msg, 0) < 0) {
+ LOG(ERROR) << "Can't send Netlink message: " << errno;
+ return false;
+ }
+ return true;
+}
+
+bool NetlinkSocket::receiveAck() {
+ if (mFailed) return false;
+
+ char buf[8192];
+
+ struct sockaddr_nl sa;
+ struct iovec iov = {buf, sizeof(buf)};
+
+ struct msghdr msg = {};
+ msg.msg_name = &sa;
+ msg.msg_namelen = sizeof(sa);
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+
+ const ssize_t status = recvmsg(mFd.get(), &msg, 0);
+ if (status < 0) {
+ LOG(ERROR) << "Failed to receive Netlink message: " << errno;
+ return false;
+ }
+ size_t remainingLen = status;
+
+ if (msg.msg_flags & MSG_TRUNC) {
+ LOG(ERROR) << "Failed to receive Netlink message: truncated";
+ return false;
+ }
+
+ for (auto nlmsg = reinterpret_cast<struct nlmsghdr*>(buf); NLMSG_OK(nlmsg, remainingLen);
+ nlmsg = NLMSG_NEXT(nlmsg, remainingLen)) {
+ // We're looking for error/ack message only, ignoring others.
+ if (nlmsg->nlmsg_type != NLMSG_ERROR) {
+ LOG(WARNING) << "Received unexpected Netlink message (ignored): " << nlmsg->nlmsg_type;
+ continue;
+ }
+
+ // Found error/ack message, return status.
+ auto nlerr = reinterpret_cast<struct nlmsgerr*>(NLMSG_DATA(nlmsg));
+ if (nlerr->error != 0) {
+ LOG(ERROR) << "Received Netlink error message: " << nlerr->error;
+ return false;
+ }
+ return true;
+ }
+ // Couldn't find any error/ack messages.
+ return false;
+}
+
+} // namespace netdevice
+} // namespace android