setupInetServer also returns port
Test: pass
Bug: 186468965
Change-Id: If3b031054717387beb93835a798f96d07a6948ad
diff --git a/libs/binder/RpcConnection.cpp b/libs/binder/RpcConnection.cpp
index f2302f7..2502d1b 100644
--- a/libs/binder/RpcConnection.cpp
+++ b/libs/binder/RpcConnection.cpp
@@ -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 @@
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 @@
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);
diff --git a/libs/binder/include/binder/RpcConnection.h b/libs/binder/include/binder/RpcConnection.h
index 2395e78..09aed13 100644
--- a/libs/binder/include/binder/RpcConnection.h
+++ b/libs/binder/include/binder/RpcConnection.h
@@ -74,9 +74,15 @@
#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.