network: UDPP2P

src/libs/network.cpp

@@ -891,6 +891,7 @@ struct P2pEndpoint {
 	uint16_t virtual_port   = 0;
 	int      nonblocking    = 0;
 	int      broadcast      = 0;
+	int      use_crypto     = 0;
 	int      send_buffer    = 9216;
 	int      receive_buffer = 40 * 1024;
 };
@@ -1095,6 +1096,7 @@ static int* P2pSocketOption(P2pEndpoint& endpoint, int option) {
 		case 0x1001: return &endpoint.send_buffer;
 		case 0x1002: return &endpoint.receive_buffer;
 		case 0x1200: return &endpoint.nonblocking;
+		case 0x20000: return &endpoint.use_crypto;
 		default: return nullptr;
 	}
 }
@@ -2459,9 +2461,9 @@ int64_t KYTY_SYSV_ABI Recvfrom(int s, void* buf, uint64_t len, int flags, void*
 		return -1;
 	}
 
-	NativeSocket                    socket = INVALID_NATIVE_SOCKET;
+	NativeSocket socket = INVALID_NATIVE_SOCKET;
-	std::shared_ptr<SocketTransport> transport;
+	SocketSlot   state;
-	if (!GetSocketBackend(s, &socket, nullptr, &transport)) {
+	if (!GetSocketBackend(s, &socket, &state)) {
 		return -1;
 	}
 
@@ -2469,6 +2471,21 @@ int64_t KYTY_SYSV_ABI Recvfrom(int s, void* buf, uint64_t len, int flags, void*
 	if (host_flags < 0) {
 		return -1;
 	}
+	if (state.p2p) {
+		if (!state.p2p->bound || (!state.p2p->nonblocking && (flags & 0x80) == 0)) {
+			return SetGuestSocketError(Posix::POSIX_EOPNOTSUPP);
+		}
+		char pending;
+		if (::recv(socket, &pending, sizeof(pending), MSG_PEEK) < 0) {
+			SetHostSocketError();
+			// Winsock reports a peeked datagram's truncation as EMSGSIZE.
+			if (*Posix::GetErrorAddr() != Posix::POSIX_EMSGSIZE) {
+				return -1;
+			}
+		}
+		// Pending UDPP2P packets still require framing and optional decryption.
+		return SetGuestSocketError(Posix::POSIX_EOPNOTSUPP);
+	}
 
 	const auto host_len = static_cast<SocketIoLength>(
 	    std::min<uint64_t>(len, std::numeric_limits<SocketIoLength>::max()));
@@ -2476,12 +2493,12 @@ int64_t KYTY_SYSV_ABI Recvfrom(int s, void* buf, uint64_t len, int flags, void*
 	SocketLength     host_addrlen = sizeof(host_addr);
 	int64_t          result       = 0;
 #if defined(_WIN32)
-	if (transport->type == SOCK_STREAM) {
+	if (state.transport->type == SOCK_STREAM) {
 		if (addr != nullptr &&
 		    ::getpeername(socket, reinterpret_cast<sockaddr*>(&host_addr), &host_addrlen) != 0) {
 			return SetHostSocketError();
 		}
-		result = ReceiveStream(*transport, static_cast<char*>(buf), host_len, host_flags,
+		result = ReceiveStream(*state.transport, static_cast<char*>(buf), host_len, host_flags,
 		                       (flags & 0x80) != 0);
 		if (result < 0) {
 			return result;
@@ -2489,7 +2506,7 @@ int64_t KYTY_SYSV_ABI Recvfrom(int s, void* buf, uint64_t len, int flags, void*
 	} else
 #endif
 	{
-		transport.reset();
+		state.transport.reset();
 		if (addr == nullptr) {
 			result = ::recv(socket, static_cast<char*>(buf), host_len, host_flags);
 		} else {

tests/KernelFileSystemTests.cpp

@@ -2173,6 +2173,53 @@ void CheckSocketWakeup() {
         "write shutdown drains queued bytes, signals EOF, and preserves reverse traffic");
   Check(Net::SocketClose(shutdown_reader) == 0 && Net::SocketClose(shutdown_writer) == 0,
         "close half-shutdown sockets");
+  const int encrypted = Net::Socket(2, 6, 0);
+  int crypto = -1;
+  uint32_t crypto_size = sizeof(crypto);
+  Check(encrypted >= 0 &&
+            Net::Getsockopt(encrypted, 0xffff, 0x20000, &crypto, &crypto_size) == 0 &&
+            crypto == 0,
+        "UDPP2P encryption defaults to disabled");
+  for (const int setting : {7, 0}) {
+    Check(Net::Setsockopt(encrypted, 0xffff, 0x20000, &setting, sizeof(setting)) == 0 &&
+              Net::Getsockopt(encrypted, 0xffff, 0x20000, &crypto, &crypto_size) == 0 &&
+              crypto == (setting != 0),
+          "UDPP2P encryption configuration retains normalized enable and disable values");
+    Check(Net::Send(encrypted, "x", 1, 0) == -1 &&
+              *Libs::Posix::GetErrorAddr() == Libs::Posix::POSIX_EOPNOTSUPP,
+          "UDPP2P configuration never exposes unframed plaintext transport");
+  }
+  std::array<uint8_t, 16> p2p_address {16, 2, 0x0e, 0x4a, 127, 0, 0, 1, 0x1e, 0x61};
+  Check(Net::Bind(encrypted, p2p_address.data(), p2p_address.size()) == 0,
+        "bind UDPP2P physical and virtual ports");
+  char untouched = '!';
+  auto source = p2p_address;
+  uint32_t source_size = source.size();
+  Check(Net::Recvfrom(encrypted, &untouched, 1, 0x80, source.data(), &source_size) == -1 &&
+            *Libs::Posix::GetErrorAddr() == Libs::Posix::POSIX_EWOULDBLOCK,
+        "per-call nonblocking UDPP2P receive reports an actually empty queue");
+  Check(Net::Setsockopt(encrypted, 0xffff, 0x1200, &enabled, sizeof(enabled)) == 0 &&
+            Net::Setsockopt(encrypted, 0xffff, 0x20000, &enabled, sizeof(enabled)) == 0 &&
+            Net::Recvfrom(encrypted, &untouched, 1, 0, source.data(), &source_size) == -1 &&
+            *Libs::Posix::GetErrorAddr() == Libs::Posix::POSIX_EWOULDBLOCK &&
+            untouched == '!' && source == p2p_address && source_size == source.size(),
+        "empty encrypted nonblocking receive preserves all caller outputs");
+  const int raw_sender = Net::Socket(2, 2, 0);
+  Check(raw_sender >= 0 &&
+            Net::Sendto(raw_sender, "pending", 7, 0, p2p_address.data(), p2p_address.size()) == 7,
+        "queue a datagram requiring unsupported UDPP2P processing");
+  const auto pending_deadline = std::chrono::steady_clock::now() + std::chrono::seconds(2);
+  while (Net::Recv(encrypted, &untouched, 1, 0) == -1 &&
+         *Libs::Posix::GetErrorAddr() == Libs::Posix::POSIX_EWOULDBLOCK &&
+         std::chrono::steady_clock::now() < pending_deadline) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+  }
+  Check(*Libs::Posix::GetErrorAddr() == Libs::Posix::POSIX_EOPNOTSUPP &&
+            Net::Recv(encrypted, &untouched, 1, 0) == -1 &&
+            *Libs::Posix::GetErrorAddr() == Libs::Posix::POSIX_EOPNOTSUPP && untouched == '!',
+        "queued packets remain queued and unsupported instead of masquerading as empty");
+  Check(Net::SocketClose(encrypted) == 0 && Net::SocketClose(raw_sender) == 0,
+        "close UDPP2P readiness fixtures");
   Check(Net::SocketClose(writer) == 0, "close wake writer");
   *net_errno = Libs::Posix::POSIX_EINVAL;
   Check(net_recv(reader, received.data(), received.size(), 0) == 0 &&