tcp: MPTCP support

For Linux define IPPROTO_MPTCP if not available to 266
For other platforms - check if constant is defined
Fall back to TCP if not available and for Unix sockets

python/test/test_tcp.py

@@ -4,6 +4,7 @@
 import tll.channel as C
 from tll.error import TLLError
 from tll.test_util import Accum, ports
+from tll.processor import Loop
 
 import os
 import pytest
@@ -326,3 +327,40 @@ def test_client_scheme():
     c.open()
 
     assert [m.name for m in s.scheme.messages] == ['Test']
+
+@pytest.mark.skipif(not hasattr(socket, 'IPPROTO_MPTCP'), reason="MPTCP not available")
+@pytest.mark.parametrize("client", ["yes", "no"])
+@pytest.mark.parametrize("server", ["yes", "no"])
+@pytest.mark.parametrize("host", [f"127.0.0.1:{ports.TCP4}", f"::1:{ports.TCP6}", "./tcp.sock"])
+def test_mptcp(host, client, server):
+    s = Accum(f'tcp://{host};mode=server;dump=frame', mptcp=server)
+    c = Accum(f'tcp://{host};mode=client;dump=frame', mptcp=client)
+
+    loop = Loop()
+
+    loop.add(s)
+    loop.add(c)
+
+    s.open()
+    c.open()
+
+    try:
+        for _ in range(10):
+            if s.result:
+                break
+            loop.step(0.001)
+        addr = s.result[-1].addr
+        s.result = []
+
+        c.post(b'xxx', seq=10)
+        s.post(b'zzz', seq=20, addr=addr)
+
+        for _ in range(10):
+            if s.result and c.result:
+                break
+            loop.step(0.001)
+        assert [(m.data.tobytes(), m.seq) for m in s.result] == [(b'xxx', 10)]
+        assert [(m.data.tobytes(), m.seq) for m in c.result] == [(b'zzz', 20)]
+    finally:
+        s.close()
+        c.close()

src/tll/channel/tcp.h

@@ -45,6 +45,7 @@ struct tcp_settings_t {
 	bool timestamping = false;
 	bool keepalive = true;
 	bool nodelay = false;
+	bool mptcp = false;
 };
 
 struct tcp_connect_t {

src/tll/channel/tcp.hpp

@@ -25,6 +25,10 @@
 #include <linux/sockios.h>
 #include <linux/net_tstamp.h>
 #include <sys/ioctl.h>
+
+#ifndef IPPROTO_MPTCP
+#define IPPROTO_MPTCP 262
+#endif
 #endif
 
 #if defined(__APPLE__) || defined(__FreeBSD__)
@@ -56,6 +60,23 @@ size_t _fill_iovec(size_t full, struct iovec * iov, const Arg &arg, const Args &
 	return _fill_iovec(full + tll::memoryview_api<Arg>::size(arg), iov + 1, std::forward<const Args &>(args)...);
 }
 
+inline int check_mptcp_proto(tll::Logger &log, const tcp_settings_t &settings, int af)
+{
+	if (!settings.mptcp)
+		return 0;
+	if (af == AF_UNIX) {
+		log.info("MPTCP not supported for Unix sockets, fall back to TCP");
+		return 0;
+	}
+
+#ifdef IPPROTO_MPTCP
+	return IPPROTO_MPTCP;
+#else
+	log.warning("MPTCP not supported on this platform, fall back to TCP");
+	return 0;
+#endif
+}
+
 } // namespace _
 
 template <typename T>
@@ -359,6 +380,7 @@ int TcpClient<T, S>::_init(const tll::Channel::Url &url, tll::Channel *master)
 	_settings.sndbuf = reader.getT("sndbuf", util::Size { 0 });
 	_settings.rcvbuf = reader.getT("rcvbuf", util::Size { 0 });
 	_settings.buffer_size = reader.getT("buffer-size", util::Size { 64 * 1024 });
+	_settings.mptcp = reader.getT("mptcp", false);
 	if (!reader)
 		return this->_log.fail(EINVAL, "Invalid url: {}", reader.error());
 
@@ -406,7 +428,7 @@ int TcpClient<T, S>::_open(const ConstConfig &url)
 	std::swap(_addr_list, *addr);
 	_addr = _addr_list.begin();
 
-	auto fd = socket((*_addr)->sa_family, SOCK_STREAM, 0);
+	auto fd = socket((*_addr)->sa_family, SOCK_STREAM, _::check_mptcp_proto(this->_log, _settings, (*_addr)->sa_family));
 	if (fd == -1)
 		return this->_log.fail(errno, "Failed to create socket: {}", strerror(errno));
 	this->_update_fd(fd);
@@ -619,7 +641,7 @@ int TcpServer<T, C>::_bind(const tll::network::sockaddr_any &addr)
 	static constexpr int sflags = SOCK_STREAM;
 #endif
 
-	tll::network::scoped_socket fd(socket(addr->sa_family, sflags, 0));
+	tll::network::scoped_socket fd(socket(addr->sa_family, sflags, _::check_mptcp_proto(this->_log, _settings, addr->sa_family)));
 	if (fd == -1)
 		return this->_log.fail(errno, "Failed to create socket: {}", strerror(errno));