mptcp: new netlink-based path manager

This path-management module is controlled over a Netlink interface. A userspace module can therefore control the establishment of new subflows and the policy to apply over those new subflows for every connection. Original author is Gregory Detal with the help of many others, see the header of the new mptcp_netlink.c file. The original implementation has been ported to a recent kernel version with adaptions to fit with Linux coding style. Signed-off-by: Gregory Detal <[email protected]> Signed-off-by: Matthieu Baerts <[email protected]> Signed-off-by: Christoph Paasch <[email protected]>
multipath-tcp · Jan 23, 2019 · 4ea5dee · 4ea5dee
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diff --git a/include/uapi/linux/mptcp.h b/include/uapi/linux/mptcp.h
@@ -0,0 +1,149 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Netlink API for Multipath TCP
+ *
+ * Author: Gregory Detal <[email protected]>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _LINUX_MPTCP_H
+#define _LINUX_MPTCP_H
+
+#define MPTCP_GENL_NAME		"mptcp"
+#define MPTCP_GENL_EV_GRP_NAME	"mptcp_events"
+#define MPTCP_GENL_CMD_GRP_NAME "mptcp_commands"
+#define MPTCP_GENL_VER		0x1
+
+/*
+ * ATTR types defined for MPTCP
+ */
+enum {
+	MPTCP_ATTR_UNSPEC = 0,
+
+	MPTCP_ATTR_TOKEN,	/* u32 */
+	MPTCP_ATTR_FAMILY,	/* u16 */
+	MPTCP_ATTR_LOC_ID,	/* u8 */
+	MPTCP_ATTR_REM_ID,	/* u8 */
+	MPTCP_ATTR_SADDR4,	/* u32 */
+	MPTCP_ATTR_SADDR6,	/* struct in6_addr */
+	MPTCP_ATTR_DADDR4,	/* u32 */
+	MPTCP_ATTR_DADDR6,	/* struct in6_addr */
+	MPTCP_ATTR_SPORT,	/* u16 */
+	MPTCP_ATTR_DPORT,	/* u16 */
+	MPTCP_ATTR_BACKUP,	/* u8 */
+	MPTCP_ATTR_ERROR,	/* u8 */
+	MPTCP_ATTR_FLAGS,	/* u16 */
+	MPTCP_ATTR_TIMEOUT,	/* u32 */
+	MPTCP_ATTR_IF_IDX,	/* s32 */
+
+	__MPTCP_ATTR_AFTER_LAST
+};
+
+#define MPTCP_ATTR_MAX (__MPTCP_ATTR_AFTER_LAST - 1)
+
+/*
+ * Events generated by MPTCP:
+ *   - MPTCP_EVENT_CREATED: token, family, saddr4 | saddr6, daddr4 | daddr6,
+ *                          sport, dport
+ *       A new connection has been created. It is the good time to allocate
+ *       memory and send ADD_ADDR if needed. Depending on the traffic-patterns
+ *       it can take a long time until the MPTCP_EVENT_ESTABLISHED is sent.
+ *
+ *   - MPTCP_EVENT_ESTABLISHED: token, family, saddr4 | saddr6, daddr4 | daddr6,
+ *                              sport, dport
+ *       A connection is established (can start new subflows).
+ *
+ *   - MPTCP_EVENT_CLOSED: token
+ *       A connection has stopped.
+ *
+ *   - MPTCP_EVENT_ANNOUNCED: token, rem_id, family, daddr4 | daddr6 [, dport]
+ *       A new address has been announced by the peer.
+ *
+ *   - MPTCP_EVENT_REMOVED: token, rem_id
+ *       An address has been lost by the peer.
+ *
+ *   - MPTCP_EVENT_SUB_ESTABLISHED: token, family, saddr4 | saddr6,
+ *                                  daddr4 | daddr6, sport, dport, backup,
+ *                                  if_idx [, error]
+ *       A new subflow has been established. 'error' should not be set.
+ *
+ *   - MPTCP_EVENT_SUB_CLOSED: token, family, saddr4 | saddr6, daddr4 | daddr6,
+ *                             sport, dport, backup, if_idx [, error]
+ *       A subflow has been closed. An error (copy of sk_err) could be set if an
+ *       error has been detected for this subflow.
+ *
+ *   - MPTCP_EVENT_SUB_PRIORITY: token, family, saddr4 | saddr6, daddr4 | daddr6,
+ *                               sport, dport, backup, if_idx [, error]
+ *       The priority of a subflow has changed. 'error' should not be set.
+ *
+ * Commands for MPTCP:
+ *   - MPTCP_CMD_ANNOUNCE: token, loc_id, family, saddr4 | saddr6 [, sport]
+ *       Announce a new address to the peer.
+ *
+ *   - MPTCP_CMD_REMOVE: token, loc_id
+ *       Announce that an address has been lost to the peer.
+ *
+ *   - MPTCP_CMD_SUB_CREATE: token, family, loc_id, rem_id, [saddr4 | saddr6,
+ *                           daddr4 | daddr6, dport [, sport, backup, if_idx]]
+ *       Create a new subflow.
+ *
+ *   - MPTCP_CMD_SUB_DESTROY: token, family, saddr4 | saddr6, daddr4 | daddr6,
+ *                            sport, dport
+ *       Close a subflow.
+ *
+ *   - MPTCP_CMD_SUB_PRIORITY: token, family, saddr4 | saddr6, daddr4 | daddr6,
+ *                             sport, dport, backup
+ *       Change the priority of a subflow.
+ *
+ *   - MPTCP_CMD_SET_FILTER: flags
+ *       Set the filter on events. Set MPTCPF_* flags to only receive specific
+ *       events. Default is to receive all events.
+ *
+ *   - MPTCP_CMD_EXIST: token
+ *       Check if this token is linked to an existing socket.
+ */
+enum {
+	MPTCP_CMD_UNSPEC = 0,
+
+	MPTCP_EVENT_CREATED,
+	MPTCP_EVENT_ESTABLISHED,
+	MPTCP_EVENT_CLOSED,
+
+	MPTCP_CMD_ANNOUNCE,
+	MPTCP_CMD_REMOVE,
+	MPTCP_EVENT_ANNOUNCED,
+	MPTCP_EVENT_REMOVED,
+
+	MPTCP_CMD_SUB_CREATE,
+	MPTCP_CMD_SUB_DESTROY,
+	MPTCP_EVENT_SUB_ESTABLISHED,
+	MPTCP_EVENT_SUB_CLOSED,
+
+	MPTCP_CMD_SUB_PRIORITY,
+	MPTCP_EVENT_SUB_PRIORITY,
+
+	MPTCP_CMD_SET_FILTER,
+
+	MPTCP_CMD_EXIST,
+
+	__MPTCP_CMD_AFTER_LAST
+};
+
+#define MPTCP_CMD_MAX (__MPTCP_CMD_AFTER_LAST - 1)
+
+enum {
+	MPTCPF_EVENT_CREATED		= (1 << 1),
+	MPTCPF_EVENT_ESTABLISHED	= (1 << 2),
+	MPTCPF_EVENT_CLOSED		= (1 << 3),
+	MPTCPF_EVENT_ANNOUNCED		= (1 << 4),
+	MPTCPF_EVENT_REMOVED		= (1 << 5),
+	MPTCPF_EVENT_SUB_ESTABLISHED	= (1 << 6),
+	MPTCPF_EVENT_SUB_CLOSED		= (1 << 7),
+	MPTCPF_EVENT_SUB_PRIORITY	= (1 << 8),
+};
+
+#endif /* _LINUX_MPTCP_H */
diff --git a/net/mptcp/Kconfig b/net/mptcp/Kconfig
@@ -39,6 +39,14 @@ config MPTCP_BINDER
 	  option to set the gateway (and/or path to) per each additional subflow
 	  via Loose Source Routing (IPv4 only).
 
+config MPTCP_NETLINK
+	tristate "MPTCP Netlink Path-Manager"
+	depends on MPTCP=y
+	---help---
+	  This path-management module is controlled over a Netlink interface. A userspace
+	  module can therefore control the establishment of new subflows and the policy
+	  to apply over those new subflows for every connection.
+
 choice
 	prompt "Default MPTCP Path-Manager"
 	default DEFAULT
@@ -54,6 +62,9 @@ choice
 	config DEFAULT_BINDER
 		bool "binder" if MPTCP_BINDER=y
 
+	config DEFAULT_NETLINK
+		bool "Netlink" if MPTCP_NETLINK=y
+
 	config DEFAULT_DUMMY
 		bool "Default"
 

diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
@@ -16,8 +16,8 @@ obj-$(CONFIG_TCP_CONG_MCTCPDESYNC) += mctcp_desync.o
 obj-$(CONFIG_MPTCP_FULLMESH) += mptcp_fullmesh.o
 obj-$(CONFIG_MPTCP_NDIFFPORTS) += mptcp_ndiffports.o
 obj-$(CONFIG_MPTCP_BINDER) += mptcp_binder.o
+obj-$(CONFIG_MPTCP_NETLINK) += mptcp_netlink.o
 obj-$(CONFIG_MPTCP_ROUNDROBIN) += mptcp_rr.o
 obj-$(CONFIG_MPTCP_REDUNDANT) += mptcp_redundant.o
 
 mptcp-$(subst m,y,$(CONFIG_IPV6)) += mptcp_ipv6.o
-
diff --git a/net/mptcp/mptcp_ctrl.c b/net/mptcp/mptcp_ctrl.c
@@ -548,6 +548,7 @@ struct sock *mptcp_hash_find(const struct net *net, const u32 token)
 	rcu_read_unlock_bh();
 	return meta_sk;
 }
+EXPORT_SYMBOL_GPL(mptcp_hash_find);
 
 void mptcp_hash_remove_bh(struct tcp_sock *meta_tp)
 {