Implements the infrastructure for MPTCP sockets.
MPTCP sockets open one in-kernel TCP socket per subflow. These subflow
sockets are only managed by the MPTCP socket that owns them and are not
visible from userspace. This commit allows a userspace program to open
an MPTCP socket with:
sock = socket(AF_INET, SOCK_STREAM, IPPROTO_MPTCP);
The resulting socket is simply a wrapper around a single regular TCP
socket, without any of the MPTCP protocol implemented over the wire.
Signed-off-by: Mat Martineau <mathew.j.martin...@linux.intel.com>
Signed-off-by: Florian Westphal <f...@strlen.de>
Signed-off-by: Peter Krystad <peter.krys...@linux.intel.com>
Signed-off-by: Matthieu Baerts <matthieu.bae...@tessares.net>
---
include/net/mptcp.h | 22 ++++++++
net/Kconfig | 1 +
net/Makefile | 1 +
net/ipv4/tcp.c | 2 +
net/mptcp/Kconfig | 10 ++++
net/mptcp/Makefile | 4 ++
net/mptcp/protocol.c | 118 +++++++++++++++++++++++++++++++++++++++++++
net/mptcp/protocol.h | 22 ++++++++
8 files changed, 180 insertions(+)
create mode 100644 include/net/mptcp.h
create mode 100644 net/mptcp/Kconfig
create mode 100644 net/mptcp/Makefile
create mode 100644 net/mptcp/protocol.c
create mode 100644 net/mptcp/protocol.h
diff --git a/include/net/mptcp.h b/include/net/mptcp.h
new file mode 100644
index 000000000000..0fe78fddc638
--- /dev/null
+++ b/include/net/mptcp.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Multipath TCP
+ *
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ */
+
+#ifndef __NET_MPTCP_H
+#define __NET_MPTCP_H
+
+#ifdef CONFIG_MPTCP
+
+void mptcp_init(void);
+
+#else
+
+static inline void mptcp_init(void)
+{
+}
+
+#endif /* CONFIG_MPTCP */
+#endif /* __NET_MPTCP_H */
diff --git a/net/Kconfig b/net/Kconfig
index d122f53c6fa2..8d5d43017feb 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -93,6 +93,7 @@ if INET
source "net/ipv4/Kconfig"
source "net/ipv6/Kconfig"
source "net/netlabel/Kconfig"
+source "net/mptcp/Kconfig"
endif # if INET
diff --git a/net/Makefile b/net/Makefile
index 449fc0b221f8..306d2e8c12c0 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -87,3 +87,4 @@ endif
obj-$(CONFIG_QRTR) += qrtr/
obj-$(CONFIG_NET_NCSI) += ncsi/
obj-$(CONFIG_XDP_SOCKETS) += xdp/
+obj-$(CONFIG_MPTCP) += mptcp/
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 5542e3d778e6..866c985a0c04 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -271,6 +271,7 @@
#include <net/icmp.h>
#include <net/inet_common.h>
#include <net/tcp.h>
+#include <net/mptcp.h>
#include <net/xfrm.h>
#include <net/ip.h>
#include <net/sock.h>
@@ -3978,4 +3979,5 @@ void __init tcp_init(void)
tcp_metrics_init();
BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
tcp_tasklet_init();
+ mptcp_init();
}
diff --git a/net/mptcp/Kconfig b/net/mptcp/Kconfig
new file mode 100644
index 000000000000..d87dfdc210cc
--- /dev/null
+++ b/net/mptcp/Kconfig
@@ -0,0 +1,10 @@
+
+config MPTCP
+ bool "Multipath TCP"
+ depends on INET
+ help
+ Multipath TCP (MPTCP) connections send and receive data over multiple
+ subflows in order to utilize multiple network paths. Each subflow
+ uses the TCP protocol, and TCP options carry header information for
+ MPTCP.
+
diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
new file mode 100644
index 000000000000..659129d1fcbf
--- /dev/null
+++ b/net/mptcp/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_MPTCP) += mptcp.o
+
+mptcp-y := protocol.o
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
new file mode 100644
index 000000000000..86db17af8c05
--- /dev/null
+++ b/net/mptcp/protocol.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <net/sock.h>
+#include <net/inet_common.h>
+#include <net/inet_hashtables.h>
+#include <net/protocol.h>
+#include <net/tcp.h>
+#include <net/mptcp.h>
+#include "protocol.h"
+
+static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct socket *subflow = msk->subflow;
+
+ pr_debug("subflow=%p", subflow->sk);
+
+ return sock_sendmsg(subflow, msg);
+}
+
+static int mptcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
+ int nonblock, int flags, int *addr_len)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct socket *subflow = msk->subflow;
+
+ pr_debug("subflow=%p", subflow->sk);
+
+ return sock_recvmsg(subflow, msg, flags);
+}
+
+static int mptcp_init_sock(struct sock *sk)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ struct socket *sf;
+ int err;
+
+ pr_debug("msk=%p", msk);
+
+ err = sock_create_kern(&init_net, PF_INET, SOCK_STREAM, IPPROTO_TCP,
+ &sf);
+ if (!err) {
+ pr_debug("subflow=%p", sf->sk);
+ msk->subflow = sf;
+ }
+
+ return err;
+}
+
+static void mptcp_close(struct sock *sk, long timeout)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+
+ inet_sk_state_store(sk, TCP_CLOSE);
+
+ if (msk->subflow) {
+ pr_debug("subflow=%p", msk->subflow->sk);
+ sock_release(msk->subflow);
+ }
+
+ sock_orphan(sk);
+ sock_put(sk);
+}
+
+static int mptcp_connect(struct sock *sk, struct sockaddr *saddr, int len)
+{
+ struct mptcp_sock *msk = mptcp_sk(sk);
+ int err;
+
+ saddr->sa_family = AF_INET;
+
+ pr_debug("msk=%p, subflow=%p", msk, msk->subflow->sk);
+
+ err = kernel_connect(msk->subflow, saddr, len, 0);
+
+ sk->sk_state = TCP_ESTABLISHED;
+
+ return err;
+}
+
+static struct proto mptcp_prot = {
+ .name = "MPTCP",
+ .owner = THIS_MODULE,
+ .init = mptcp_init_sock,
+ .close = mptcp_close,
+ .accept = inet_csk_accept,
+ .connect = mptcp_connect,
+ .shutdown = tcp_shutdown,
+ .sendmsg = mptcp_sendmsg,
+ .recvmsg = mptcp_recvmsg,
+ .hash = inet_hash,
+ .unhash = inet_unhash,
+ .get_port = inet_csk_get_port,
+ .obj_size = sizeof(struct mptcp_sock),
+ .no_autobind = 1,
+};
+
+static struct inet_protosw mptcp_protosw = {
+ .type = SOCK_STREAM,
+ .protocol = IPPROTO_MPTCP,
+ .prot = &mptcp_prot,
+ .ops = &inet_stream_ops,
+};
+
+void __init mptcp_init(void)
+{
+ if (proto_register(&mptcp_prot, 1) != 0)
+ panic("Failed to register MPTCP proto.\n");
+
+ inet_register_protosw(&mptcp_protosw);
+}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
new file mode 100644
index 000000000000..972204835421
--- /dev/null
+++ b/net/mptcp/protocol.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Multipath TCP
+ *
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ */
+
+#ifndef __MPTCP_PROTOCOL_H
+#define __MPTCP_PROTOCOL_H
+
+/* MPTCP connection sock */
+struct mptcp_sock {
+ /* inet_connection_sock must be the first member */
+ struct inet_connection_sock sk;
+ struct socket *subflow;
+};
+
+static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
+{
+ return (struct mptcp_sock *)sk;
+}
+
+#endif /* __MPTCP_PROTOCOL_H */
--
2.22.0
