setupInetServer also returns port (b00ff661) · Commits · e / os / platform_frameworks_native

libs/binder/RpcConnection.cpp

+62 −2

Original line number	Diff line number	Diff line
		@@ -19,6 +19,7 @@
		#include <binder/RpcConnection.h>

		#include <arpa/inet.h>
		#include <inttypes.h>
		#include <netdb.h>
		#include <netinet/in.h>
		#include <sys/socket.h>
		@@ -45,9 +46,55 @@ extern "C" pid_t gettid();

		namespace android {

		using base::borrowed_fd;
		using base::unique_fd;
		using AddrInfo = std::unique_ptr<addrinfo, decltype(&freeaddrinfo)>;

		namespace {
		bool checkSockaddrSize(const char* name, size_t actual, size_t expected) {
		if (actual >= expected) return true;
		ALOGW("getSockaddrPort: family is %s but size is %zu < %zu", name, actual, expected);
		return false;
		}

		// Get the port number of \|storage\| for certain families. Requires storage->sa_family to be
		// set to a known family; otherwise, return nullopt.
		std::optional<unsigned int> getSockaddrPort(const sockaddr* storage, socklen_t len) {
		switch (storage->sa_family) {
		case AF_INET: {
		if (!checkSockaddrSize("INET", len, sizeof(sockaddr_in))) return std::nullopt;
		auto inetStorage = reinterpret_cast<const sockaddr_in*>(storage);
		return ntohs(inetStorage->sin_port);
		}
		default: {
		uint16_t family = storage->sa_family;
		ALOGW("Don't know how to infer port for family %" PRIu16, family);
		return std::nullopt;
		}
		}
		}

		std::optional<unsigned int> getSocketPort(borrowed_fd socketfd,
		const RpcConnection::SocketAddress& socketAddress) {
		sockaddr_storage storage{};
		socklen_t len = sizeof(storage);
		auto storagePtr = reinterpret_cast<sockaddr*>(&storage);
		if (0 != getsockname(socketfd.get(), storagePtr, &len)) {
		int savedErrno = errno;
		ALOGE("Could not getsockname at %s: %s", socketAddress.toString().c_str(),
		strerror(savedErrno));
		return std::nullopt;
		}

		// getsockname does not fill in family, but getSockaddrPort() needs it.
		if (storage.ss_family == AF_UNSPEC) {
		storage.ss_family = socketAddress.addr()->sa_family;
		}
		return getSockaddrPort(storagePtr, len);
		}

		} // namespace

		RpcConnection::SocketAddress::~SocketAddress() {}

		RpcConnection::RpcConnection() {
		@@ -166,14 +213,27 @@ AddrInfo GetAddrInfo(const char* addr, unsigned int port) {
		return AddrInfo(aiStart, &freeaddrinfo);
		}

		bool RpcConnection::setupInetServer(unsigned int port) {
		bool RpcConnection::setupInetServer(unsigned int port, unsigned int* assignedPort) {
		const char* kAddr = "127.0.0.1";

		if (assignedPort != nullptr) *assignedPort = 0;
		auto aiStart = GetAddrInfo(kAddr, port);
		if (aiStart == nullptr) return false;
		for (auto ai = aiStart.get(); ai != nullptr; ai = ai->ai_next) {
		InetSocketAddress socketAddress(ai->ai_addr, ai->ai_addrlen, kAddr, port);
		if (setupSocketServer(socketAddress)) return true;
		if (!setupSocketServer(socketAddress)) {
		continue;
		}
		auto realPort = getSocketPort(mServer.get(), socketAddress);
		LOG_ALWAYS_FATAL_IF(!realPort.has_value(), "Unable to get port number after setting up %s",
		socketAddress.toString().c_str());
		LOG_ALWAYS_FATAL_IF(port != 0 && *realPort != port,
		"Requesting inet server on %s but it is set up on %u.",
		socketAddress.toString().c_str(), *realPort);
		if (assignedPort != nullptr) {
		assignedPort = realPort;
		}
		return true;
		}
		ALOGE("None of the socket address resolved for %s:%u can be set up as inet server.", kAddr,
		port);

libs/binder/include/binder/RpcConnection.h

+8 −2

Original line number	Diff line number	Diff line
		@@ -74,9 +74,15 @@ public:
		#endif // __BIONIC__

		/**
		* Creates an RPC server at the current port.
		* Creates an RPC server at the current port using IPv4.
		*
		* TODO(b/182914638): IPv6 support
		*
		* Set \|port\| to 0 to pick an ephemeral port; see discussion of
		* /proc/sys/net/ipv4/ip_local_port_range in ip(7). In this case, \|assignedPort\|
		* will be set to the picked port number, if it is not null.
		*/
		[[nodiscard]] bool setupInetServer(unsigned int port);
		[[nodiscard]] bool setupInetServer(unsigned int port, unsigned int* assignedPort);

		/**
		* Connects to an RPC server at the given address and port.