Extend libnetdevice for Netlink Proxy (06c2c0de) · Commits · e / os / android_hardware_interfaces

automotive/can/1.0/default/libnetdevice/NetlinkSocket.cpp

+78 −15

Original line number	Diff line number	Diff line
		@@ -27,7 +27,8 @@ namespace android::netdevice {
		*/
		static constexpr bool kSuperVerbose = false;

		NetlinkSocket::NetlinkSocket(int protocol) : mProtocol(protocol) {
		NetlinkSocket::NetlinkSocket(int protocol, unsigned int pid, uint32_t groups)
		: mProtocol(protocol) {
		mFd.reset(socket(AF_NETLINK, SOCK_RAW, protocol));
		if (!mFd.ok()) {
		PLOG(ERROR) << "Can't open Netlink socket";
		@@ -35,21 +36,23 @@ NetlinkSocket::NetlinkSocket(int protocol) : mProtocol(protocol) {
		return;
		}

		struct sockaddr_nl sa = {};
		sockaddr_nl sa = {};
		sa.nl_family = AF_NETLINK;
		sa.nl_pid = pid;
		sa.nl_groups = groups;

		if (bind(mFd.get(), reinterpret_cast<struct sockaddr*>(&sa), sizeof(sa)) < 0) {
		if (bind(mFd.get(), reinterpret_cast<sockaddr*>(&sa), sizeof(sa)) < 0) {
		PLOG(ERROR) << "Can't bind Netlink socket";
		mFd.reset();
		mFailed = true;
		}
		}

		bool NetlinkSocket::send(struct nlmsghdr* nlmsg, size_t totalLen) {
		bool NetlinkSocket::send(nlmsghdr* nlmsg, size_t totalLen) {
		if constexpr (kSuperVerbose) {
		nlmsg->nlmsg_seq = mSeq;
		LOG(VERBOSE) << (mFailed ? "(not) " : "")
		<< "sending Netlink message: " << toString(nlmsg, totalLen, mProtocol);
		<< "sending Netlink message: " << toString({nlmsg, totalLen}, mProtocol);
		}

		if (mFailed) return false;
		@@ -58,12 +61,12 @@ bool NetlinkSocket::send(struct nlmsghdr* nlmsg, size_t totalLen) {
		nlmsg->nlmsg_seq = mSeq++;
		nlmsg->nlmsg_flags \|= NLM_F_ACK;

		struct iovec iov = {nlmsg, nlmsg->nlmsg_len};
		iovec iov = {nlmsg, nlmsg->nlmsg_len};

		struct sockaddr_nl sa = {};
		sockaddr_nl sa = {};
		sa.nl_family = AF_NETLINK;

		struct msghdr msg = {};
		msghdr msg = {};
		msg.msg_name = &sa;
		msg.msg_namelen = sizeof(sa);
		msg.msg_iov = &iov;
		@@ -76,15 +79,65 @@ bool NetlinkSocket::send(struct nlmsghdr* nlmsg, size_t totalLen) {
		return true;
		}

		bool NetlinkSocket::send(const nlbuf<nlmsghdr>& msg, const sockaddr_nl& sa) {
		if constexpr (kSuperVerbose) {
		LOG(VERBOSE) << (mFailed ? "(not) " : "")
		<< "sending Netlink message: " << toString(msg, mProtocol);
		}

		if (mFailed) return false;
		const auto rawMsg = msg.getRaw();
		const auto bytesSent = sendto(mFd.get(), rawMsg.ptr(), rawMsg.len(), 0,
		reinterpret_cast<const sockaddr*>(&sa), sizeof(sa));
		if (bytesSent < 0) {
		PLOG(ERROR) << "Can't send Netlink message";
		return false;
		}
		return true;
		}

		std::optional<nlbuf<nlmsghdr>> NetlinkSocket::receive(void* buf, size_t bufLen) {
		sockaddr_nl sa = {};
		return receive(buf, bufLen, sa);
		}

		std::optional<nlbuf<nlmsghdr>> NetlinkSocket::receive(void* buf, size_t bufLen, sockaddr_nl& sa) {
		if (mFailed) return std::nullopt;

		socklen_t saLen = sizeof(sa);
		if (bufLen == 0) {
		LOG(ERROR) << "Receive buffer has zero size!";
		return std::nullopt;
		}
		const auto bytesReceived =
		recvfrom(mFd.get(), buf, bufLen, MSG_TRUNC, reinterpret_cast<sockaddr*>(&sa), &saLen);
		if (bytesReceived <= 0) {
		PLOG(ERROR) << "Failed to receive Netlink message";
		return std::nullopt;
		} else if (unsigned(bytesReceived) > bufLen) {
		PLOG(ERROR) << "Received data larger than the receive buffer! " << bytesReceived << " > "
		<< bufLen;
		return std::nullopt;
		}

		nlbuf<nlmsghdr> msg(reinterpret_cast<nlmsghdr*>(buf), bytesReceived);
		if constexpr (kSuperVerbose) {
		LOG(VERBOSE) << "received " << toString(msg, mProtocol);
		}
		return msg;
		}

		/* TODO(161389935): Migrate receiveAck to use nlmsg<> internally. Possibly reuse
		* NetlinkSocket::receive(). */
		bool NetlinkSocket::receiveAck() {
		if (mFailed) return false;

		char buf[8192];

		struct sockaddr_nl sa;
		struct iovec iov = {buf, sizeof(buf)};
		sockaddr_nl sa;
		iovec iov = {buf, sizeof(buf)};

		struct msghdr msg = {};
		msghdr msg = {};
		msg.msg_name = &sa;
		msg.msg_namelen = sizeof(sa);
		msg.msg_iov = &iov;
		@@ -102,11 +155,11 @@ bool NetlinkSocket::receiveAck() {
		return false;
		}

		for (auto nlmsg = reinterpret_cast<struct nlmsghdr*>(buf); NLMSG_OK(nlmsg, remainingLen);
		for (auto nlmsg = reinterpret_cast<nlmsghdr*>(buf); NLMSG_OK(nlmsg, remainingLen);
		nlmsg = NLMSG_NEXT(nlmsg, remainingLen)) {
		if constexpr (kSuperVerbose) {
		LOG(VERBOSE) << "received Netlink response: "
		<< toString(nlmsg, sizeof(buf), mProtocol);
		<< toString({nlmsg, nlmsg->nlmsg_len}, mProtocol);
		}

		// We're looking for error/ack message only, ignoring others.
		@@ -116,7 +169,7 @@ bool NetlinkSocket::receiveAck() {
		}

		// Found error/ack message, return status.
		auto nlerr = reinterpret_cast<struct nlmsgerr*>(NLMSG_DATA(nlmsg));
		const auto nlerr = reinterpret_cast<nlmsgerr*>(NLMSG_DATA(nlmsg));
		if (nlerr->error != 0) {
		LOG(ERROR) << "Received Netlink error message: " << nlerr->error;
		return false;
		@@ -127,4 +180,14 @@ bool NetlinkSocket::receiveAck() {
		return false;
		}

		std::optional<unsigned int> NetlinkSocket::getSocketPid() {
		sockaddr_nl sa = {};
		socklen_t sasize = sizeof(sa);
		if (getsockname(mFd.get(), reinterpret_cast<sockaddr*>(&sa), &sasize) < 0) {
		PLOG(ERROR) << "Failed to getsockname() for netlink_fd!";
		return std::nullopt;
		}
		return sa.nl_pid;
		}

		} // namespace android::netdevice

automotive/can/1.0/default/libnetdevice/include/libnetdevice/NetlinkSocket.h

+53 −4

Original line number	Diff line number	Diff line
		@@ -19,9 +19,12 @@
		#include <android-base/macros.h>
		#include <android-base/unique_fd.h>
		#include <libnetdevice/NetlinkRequest.h>
		#include <libnetdevice/nlbuf.h>

		#include <linux/netlink.h>

		#include <optional>

		namespace android::netdevice {

		/**
		@@ -31,12 +34,23 @@ namespace android::netdevice {
		* use multiple instances over multiple threads.
		*/
		struct NetlinkSocket {
		NetlinkSocket(int protocol);
		/**
		* NetlinkSocket constructor.
		*
		* \param protocol the Netlink protocol to use.
		* \param pid port id. Default value of 0 allows the kernel to assign us a unique pid. (NOTE:
		* this is NOT the same as process id!)
		* \param groups Netlink multicast groups to listen to. This is a 32-bit bitfield, where each
		* bit is a different group. Default value of 0 means no groups are selected. See man netlink.7
		* for more details.
		*/
		NetlinkSocket(int protocol, unsigned int pid = 0, uint32_t groups = 0);

		/**
		* Send Netlink message to Kernel.
		* Send Netlink message to Kernel. The sequence number will be automatically incremented, and
		* the NLM_F_ACK (request ACK) flag will be set.
		*
		* \param msg Message to send, nlmsg_seq will be set to next sequence number
		* \param msg Message to send.
		* \return true, if succeeded
		*/
		template <class T, unsigned int BUFSIZE>
		@@ -45,6 +59,34 @@ struct NetlinkSocket {
		return send(req.header(), req.totalLength);
		}

		/**
		* Send Netlink message. The message will be sent as is, without any modification.
		*
		* \param msg Message to send.
		* \param sa Destination address.
		* \return true, if succeeded
		*/
		bool send(const nlbuf<nlmsghdr>& msg, const sockaddr_nl& sa);

		/**
		* Receive Netlink data.
		*
		* \param buf buffer to hold message data.
		* \param bufLen length of buf.
		* \return nlbuf with message data, std::nullopt on error.
		*/
		std::optional<nlbuf<nlmsghdr>> receive(void* buf, size_t bufLen);

		/**
		* Receive Netlink data with address info.
		*
		* \param buf buffer to hold message data.
		* \param bufLen length of buf.
		* \param sa Blank struct that recvfrom will populate with address info.
		* \return nlbuf with message data, std::nullopt on error.
		*/
		std::optional<nlbuf<nlmsghdr>> receive(void* buf, size_t bufLen, sockaddr_nl& sa);

		/**
		* Receive Netlink ACK message from Kernel.
		*
		@@ -52,6 +94,13 @@ struct NetlinkSocket {
		*/
		bool receiveAck();

		/**
		* Gets the PID assigned to mFd.
		*
		* \return pid that mSocket is bound to.
		*/
		std::optional<unsigned int> getSocketPid();

		private:
		const int mProtocol;

		@@ -59,7 +108,7 @@ struct NetlinkSocket {
		base::unique_fd mFd;
		bool mFailed = false;

		bool send(struct nlmsghdr* msg, size_t totalLen);
		bool send(nlmsghdr* msg, size_t totalLen);

		DISALLOW_COPY_AND_ASSIGN(NetlinkSocket);
		};

automotive/can/1.0/default/libnetdevice/include/libnetdevice/nlbuf.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -53,6 +53,12 @@ class nlbuf {
		static constexpr size_t hdrlen = align(sizeof(T));

		public:
		/**
		* Constructor for nlbuf.
		*
		* \param data A pointer to the data the nlbuf wraps.
		* \param bufferLen Length of buffer.
		*/
		nlbuf(const T* data, size_t bufferLen) : mData(data), mBufferEnd(pointerAdd(data, bufferLen)) {}

		const T* operator->() const {

automotive/can/1.0/default/libnetdevice/include/libnetdevice/printer.h

+11 −1

Original line number	Diff line number	Diff line
		@@ -16,12 +16,22 @@

		#pragma once

		#include <libnetdevice/nlbuf.h>

		#include <linux/netlink.h>

		#include <string>

		namespace android::netdevice {

		std::string toString(const nlmsghdr* hdr, size_t bufLen, int protocol);
		/**
		* Stringify a Netlink message.
		*
		* \param hdr Pointer to the message(s) to print.
		* \param protocol Which Netlink protocol hdr uses.
		* \param printPayload True will stringify message data, false will only stringify the header(s).
		* \return Stringified message.
		*/
		std::string toString(const nlbuf<nlmsghdr> hdr, int protocol, bool printPayload = false);

		} // namespace android::netdevice

automotive/can/1.0/default/libnetdevice/printer.cpp

+12 −6

Original line number	Diff line number	Diff line
		@@ -62,13 +62,20 @@ static void flagsToStream(std::stringstream& ss, __u16 nlmsg_flags) {
		}

		static void toStream(std::stringstream& ss, const nlbuf<uint8_t> data) {
		const auto rawData = data.getRaw();
		const auto dataLen = rawData.len();
		ss << std::hex;
		if (dataLen > 16) ss << std::endl << " 0000 ";
		int i = 0;
		for (const auto byte : data.getRaw()) {
		for (const auto byte : rawData) {
		if (i++ > 0) ss << ' ';
		ss << std::setw(2) << unsigned(byte);
		if (i % 16 == 0) {
		ss << std::endl << ' ' << std::dec << std::setw(4) << i << std::hex;
		}
		}
		ss << std::dec;
		if (dataLen > 16) ss << std::endl;
		}

		static void toStream(std::stringstream& ss, const nlbuf<nlattr> attr,
		@@ -105,7 +112,7 @@ static void toStream(std::stringstream& ss, const nlbuf<nlattr> attr,
		}
		}

		static std::string toString(const nlbuf<nlmsghdr> hdr, int protocol) {
		std::string toString(const nlbuf<nlmsghdr> hdr, int protocol, bool printPayload) {
		if (!hdr.firstOk()) return "nlmsg{buffer overflow}";

		std::stringstream ss;
		@@ -133,10 +140,13 @@ static std::string toString(const nlbuf<nlmsghdr> hdr, int protocol) {
		}
		if (hdr->nlmsg_seq != 0) ss << ", seq=" << hdr->nlmsg_seq;
		if (hdr->nlmsg_pid != 0) ss << ", pid=" << hdr->nlmsg_pid;
		ss << ", len=" << hdr->nlmsg_len;

		ss << ", crc=" << std::hex << std::setw(4) << crc16(hdr.data<uint8_t>()) << std::dec;
		ss << "} ";

		if (!printPayload) return ss.str();

		if (!msgDescMaybe.has_value()) {
		toStream(ss, hdr.data<uint8_t>());
		} else {
		@@ -161,8 +171,4 @@ static std::string toString(const nlbuf<nlmsghdr> hdr, int protocol) {
		return ss.str();
		}

		std::string toString(const nlmsghdr* hdr, size_t bufLen, int protocol) {
		return toString({hdr, bufLen}, protocol);
		}

		} // namespace android::netdevice