Support only one kernel at run-time,

.github/workflows/multipath-tcp.org.yml

@@ -0,0 +1,31 @@
+name: multipath-tcp.org kernel
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: dependencies
+      run: sudo apt-get -y install autoconf-archive git
+    - name: build and install ELL
+      run: |
+        git clone git://git.kernel.org/pub/scm/libs/ell/ell.git
+        cd ell
+        git checkout 0.30
+        ./bootstrap
+        ./configure --prefix=/usr
+        sudo make install
+    - name: bootstrap
+      run: ./bootstrap
+    - name: configure
+      run: ./configure --with-kernel=multipath-tcp.org
+    - name: make
+      run: make

configure.ac

@@ -108,6 +108,19 @@ AC_DEFINE_UNQUOTED([MPTCPD_LOGGER],
                    [Log message destination.])
 AC_SUBST([mptcpd_logger],[$enable_logging])
 
+# Allow the user to choose support for either the upstream or
+# multipath-tcp.org kernel.
+AC_ARG_WITH([kernel],
+     [AS_HELP_STRING([--with-kernel[=KERNEL]],
+                     [Support a specific MPTCP capable kernel
+                      (upstream, multipath-tcp.org, auto)
+                      @<:@default=auto@:>@])],
+     [AS_CASE([$withval],
+              [upstream | multipath-tcp.org | auto],
+              [with_kernel=$withval],
+              [AC_MSG_ERROR([invalid MPTCP capable kernel: $withval])])],
+     [with_kernel=auto])
+
 # Allow the user to set the default path manager plugin at 'configure-time'.
 AC_ARG_WITH([path-manager],
      [AS_HELP_STRING([--with-path-manager[=PLUGIN]],
@@ -200,29 +213,41 @@ AH_TEMPLATE([HAVE_LINUX_MPTCP_H_UPSTREAM],
 AH_TEMPLATE([HAVE_LINUX_MPTCP_H_MPTCP_ORG],
             [Define to 1 if you have the multipath-tcp.org kernel
             <linux/mptcp.h> header.])
-AH_TEMPLATE([HAVE_LINUX_MPTCP_H_UPSTREAM_EVENTS],
-            [Define to 1 if <linux/mptcp.h> supports MPTCP genl events.])
 AC_CHECK_HEADERS([linux/mptcp.h],
-   [
-    AX_CHECK_DEFINE(
-        [linux/mptcp.h],
-        [MPTCP_PM_NAME],
-        [AC_DEFINE([HAVE_LINUX_MPTCP_H_UPSTREAM], [1])
-         AX_CHECK_DEFINE([linux/mptcp.h],
-                         [MPTCP_PM_EV_GRP_NAME],
-                         [AC_DEFINE([HAVE_LINUX_MPTCP_H_UPSTREAM_EVENTS],
-                                    [1])
-                         ])
+  [
+   MPTCPD_IF_UPSTREAM_KERNEL(
+     [
+      AC_DEFINE([HAVE_LINUX_MPTCP_H_UPSTREAM], [1])
+      AS_IF([test "x$with_kernel" = "xauto"],
+            [with_kernel=upstream])
+     ],
+     [
+      MPTCPD_IF_MPTCP_ORG_KERNEL(
+        [
+         AC_DEFINE([HAVE_LINUX_MPTCP_H_MPTCP_ORG], [1])
+         AS_IF([test "x$with_kernel" = "xauto"],
+               [with_kernel=multipath-tcp.org])
         ],
         [
-         AX_CHECK_DEFINE(
-             [linux/mptcp.h],
-             [MPTCP_GENL_NAME],
-             [AC_DEFINE([HAVE_LINUX_MPTCP_H_MPTCP_ORG], [1])],
-             [AC_MSG_ERROR([Discrepancy in <linux/mptcp.h>.])])
+         AC_MSG_WARN([Unsupported <linux/mptcp.h> header. Using fallback.])
         ])
-   ],
-   [AC_MSG_WARN([<linux/mptcp.h> header not found. Using fallback.])])
+      ])
+  ],
+  [
+   AC_MSG_WARN([<linux/mptcp.h> header not found. Using fallback.])
+  ])
+
+AS_IF([test "x$with_kernel" = "xauto"], [with_kernel=upstream])
+
+AM_CONDITIONAL([HAVE_UPSTREAM_KERNEL],
+               [test "x$with_kernel" = "xupstream"])
+
+AH_TEMPLATE([HAVE_UPSTREAM_KERNEL],
+            [Define to 1 if mptcpd should support the upstream kernel.])
+AS_IF([test "x$with_kernel" = "xupstream"],
+      [AC_DEFINE([HAVE_UPSTREAM_KERNEL])
+       AC_MSG_NOTICE([Building support for upstream kernel.])],
+      [AC_MSG_NOTICE([Building support for multipath-tcp.org kernel.])])
 
 # ---------------------------------------------------------------
 # Checks for typedefs, structures, and compiler characteristics.
@@ -249,14 +274,14 @@ LIBS="$LIBS $ELL_LIBS"
 dnl l_genl_msg_get_extended_error() was introduced in ELL v0.31.
 AC_CHECK_FUNC([l_genl_msg_get_extended_error],
               [AC_DEFINE([HAVE_L_GENL_MSG_GET_EXTENDED_ERROR],
-	                 [],
-			 [ELL has l_genl_msg_get_extended_error()])])
+                         [],
+                         [ELL has l_genl_msg_get_extended_error()])])
 
 dnl l_hashmap_replace() was introduced in ELL v0.33.
 AC_CHECK_FUNC([l_hashmap_replace],
               [AC_DEFINE([HAVE_L_HASHMAP_REPLACE],
-	                 [],
-			 [ELL has l_hashmap_replace()])])
+                         [],
+                         [ELL has l_hashmap_replace()])])
 LIBS=$mptcpd_save_libs
 
 # ---------------------------------------------------------------
@@ -272,29 +297,29 @@ AX_APPEND_COMPILE_FLAGS([-Wextra -Werror -pedantic])
 # ---------------------------------------------------------------
 
 AC_ARG_ENABLE(stack-protection,
-	[AS_HELP_STRING([--disable-stack-protection],
-		[Disable compiler stack protection.
-		FORTIFY_SOURCE=2 and -fstack-protector-strong]
-	)],
-	[],
-	[enable_stack_protection=yes])
+        [AS_HELP_STRING([--disable-stack-protection],
+                [Disable compiler stack protection.
+                FORTIFY_SOURCE=2 and -fstack-protector-strong]
+        )],
+        [],
+        [enable_stack_protection=yes])
 
 AS_IF([test "x$enable_stack_protection" = "xyes"],
-	[
-	# Fortify source
-	# Enabling optimization implies _FORTIFY_SOURCE on some platforms.
-	# Explicitly redefine to _FORTIFY_SOURCE=2 to make sure we have the
-	# desired fortification level.
-	AX_APPEND_FLAG([-U_FORTIFY_SOURCE], [CPPFLAGS])
-	AX_APPEND_FLAG([-D_FORTIFY_SOURCE=2], [CPPFLAGS])
-
-	# Stack-based buffer overrun detection
-	MPTCPD_ADD_COMPILE_FLAG([-fstack-protector-strong],
-	                        [# GCC < 4.9
-	                         MPTCPD_ADD_COMPILE_FLAG([-fstack-protector])
-	                        ])
-	],[]
-	)
+        [
+        # Fortify source
+        # Enabling optimization implies _FORTIFY_SOURCE on some platforms.
+        # Explicitly redefine to _FORTIFY_SOURCE=2 to make sure we have the
+        # desired fortification level.
+        AX_APPEND_FLAG([-U_FORTIFY_SOURCE], [CPPFLAGS])
+        AX_APPEND_FLAG([-D_FORTIFY_SOURCE=2], [CPPFLAGS])
+
+        # Stack-based buffer overrun detection
+        MPTCPD_ADD_COMPILE_FLAG([-fstack-protector-strong],
+                                [# GCC < 4.9
+                                 MPTCPD_ADD_COMPILE_FLAG([-fstack-protector])
+                                ])
+        ],[]
+        )
 
 # Format string vulnerabilities
 # -Wformat=2 implies:

include/linux/mptcp_upstream.h

@@ -48,6 +48,8 @@ enum {
 	MPTCP_PM_ATTR_ADDR,				/* nested address */
 	MPTCP_PM_ATTR_RCV_ADD_ADDRS,			/* u32 */
 	MPTCP_PM_ATTR_SUBFLOWS,				/* u32 */
+	MPTCP_PM_ATTR_TOKEN,				/* u32 */
+	MPTCP_PM_ATTR_LOC_ID,				/* u8 */
 
 	__MPTCP_PM_ATTR_MAX
 };
@@ -84,6 +86,8 @@ enum {
 	MPTCP_PM_CMD_SET_LIMITS,
 	MPTCP_PM_CMD_GET_LIMITS,
 	MPTCP_PM_CMD_SET_FLAGS,
+        MPTCP_PM_CMD_ANNOUNCE,
+        MPTCP_PM_CMD_REMOVE,
 
 	__MPTCP_PM_CMD_AFTER_LAST
 };

include/mptcpd/private/mptcp_upstream.h

@@ -16,8 +16,7 @@
 # include "mptcpd/private/config.h"
 #endif
 
-#if defined(HAVE_LINUX_MPTCP_H_UPSTREAM) \
-    && defined(HAVE_LINUX_MPTCP_H_UPSTREAM_EVENTS)
+#ifdef HAVE_LINUX_MPTCP_H_UPSTREAM
 # include <linux/mptcp.h>
 #else
 /*

include/mptcpd/private/netlink_pm.h

@@ -15,6 +15,9 @@
 extern "C" {
 #endif
 
+struct mptcpd_pm_cmd_ops;
+struct mptcpd_kpm_cmd_ops;
+
 /**
  * @struct mptcpd_netlink_pm
  *

include/mptcpd/private/path_manager.h

@@ -134,6 +134,9 @@ struct mptcpd_pm_cmd_ops
          *                  ignored if it is zero.
          * @param[in] id    MPTCP local address ID.
          * @param[in] token MPTCP connection token.
+         *
+         * @return @c 0 if operation was successful. -1 or @c errno
+         *         otherwise.
          */
         int (*add_addr)(struct mptcpd_pm *pm,
                         struct sockaddr const *addr,
@@ -142,6 +145,12 @@ struct mptcpd_pm_cmd_ops
 
         /**
          * @brief Stop advertising network address to peers.
+         * @param[in] pm         The mptcpd path manager object.
+         * @param[in] address_id MPTCP local address ID.
+         * @param[in] token      MPTCP connection token.
+         *
+         * @return @c 0 if operation was successful. -1 or @c errno
+         *         otherwise.
          */
         int (*remove_addr)(struct mptcpd_pm *pm,
                            mptcpd_aid_t address_id,
@@ -177,12 +186,12 @@ struct mptcpd_pm_cmd_ops
         /**
          * @brief Remove a subflow.
          *
-         * @param[in] pm                The mptcpd path manager object.
-         * @param[in] token             MPTCP connection token.
-         * @param[in] local_addr        MPTCP subflow local address
-         *                              information, including the port.
-         * @param[in] remote_addr       MPTCP subflow remote address
-         *                              information, including the port.
+         * @param[in] pm          The mptcpd path manager object.
+         * @param[in] token       MPTCP connection token.
+         * @param[in] local_addr  MPTCP subflow local address
+         *                        information, including the port.
+         * @param[in] remote_addr MPTCP subflow remote address
+         *                        information, including the port.
          *
          * @return @c 0 if operation was successful. @c errno
          *         otherwise.
@@ -195,14 +204,14 @@ struct mptcpd_pm_cmd_ops
         /**
          * @brief Set priority of a subflow.
          *
-         * @param[in] pm                The mptcpd path manager object.
-         * @param[in] token             MPTCP connection token.
-         * @param[in] local_addr        MPTCP subflow local address
-         *                              information, including the port.
-         * @param[in] remote_addr       MPTCP subflow remote address
-         *                              information, including the port.
-         * @param[in] backup            Whether or not to set the MPTCP
-         *                              subflow backup priority flag.
+         * @param[in] pm          The mptcpd path manager object.
+         * @param[in] token       MPTCP connection token.
+         * @param[in] local_addr  MPTCP subflow local address
+         *                        information, including the port.
+         * @param[in] remote_addr MPTCP subflow remote address
+         *                        information, including the port.
+         * @param[in] backup      Whether or not to set the MPTCP
+         *                        subflow backup priority flag.
          *
          * @return @c 0 if operation was successful. @c errno
          *         otherwise.
@@ -238,6 +247,9 @@ struct mptcpd_kpm_cmd_ops
          * @param[in] id    MPTCP local address ID.
          * @param[in] flags
          * @param[in] index Network interface index (optional).
+         *
+         * @return @c 0 if operation was successful. -1 or @c errno
+         *         otherwise.
          */
         int (*add_addr)(struct mptcpd_pm *pm,
                         struct sockaddr const *addr,
@@ -247,6 +259,12 @@ struct mptcpd_kpm_cmd_ops
 
         /**
          * @brief Stop advertising network address to peers.
+         *
+         * @param[in] pm         The mptcpd path manager object.
+         * @param[in] address_id MPTCP local address ID.
+         *
+         * @return @c 0 if operation was successful. -1 or @c errno
+         *         otherwise.
          */
         int (*remove_addr)(struct mptcpd_pm *pm,
                            mptcpd_aid_t address_id);

m4/mptcpd_kernel.m4

@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: BSD-3-Clause
+#
+# Copyright (c) 2021, Intel Corporation
+
+#serial 1
+
+# MPTCPD_IF_UPSTREAM_KERNEL([ACTION-IF-TRUE], [ACTION-IF-FALSE])
+#
+# Check if the <linux/mptcp.h> header for the upstream kernel is
+# available in the system include path.
+AC_DEFUN([MPTCPD_IF_UPSTREAM_KERNEL],
+[
+ AC_CACHE_CHECK([for MPTCP_PM_CMD_ANNOUNCE in linux/mptcp.h],
+   [mptcpd_cv_header_upstream],
+   [
+    AC_COMPILE_IFELSE([
+      AC_LANG_SOURCE([
+#include <linux/mptcp.h>
+
+int announce_cmd(void) { return MPTCP_PM_CMD_ANNOUNCE; }
+      ])
+    ],
+    [mptcpd_cv_header_upstream=yes],
+    [mptcpd_cv_header_upstream=no])
+   ])
+
+ AS_IF([test "x$mptcpd_cv_header_upstream" = xyes], [$1], [$2])
+])
+
+# MPTCPD_IF_MPTCP_ORG_KERNEL([ACTION-IF-TRUE], [ACTION-IF-FALSE])
+#
+# Check if the <linux/mptcp.h> header for the multipath-tcp.org kernel
+# is available in the system include path.
+AC_DEFUN([MPTCPD_IF_MPTCP_ORG_KERNEL],
+[
+ AX_CHECK_DEFINE([linux/mptcp.h], [MPTCP_GENL_NAME], [$1], [$2])
+])

src/Makefile.am

@@ -19,11 +19,15 @@ libpath_manager_la_SOURCES =	\
 	configuration.c		\
 	netlink_pm.c		\
 	netlink_pm.h		\
-	netlink_pm_mptcp_org.c	\
-	netlink_pm_upstream.c	\
 	path_manager.c		\
 	path_manager.h
 
+if HAVE_UPSTREAM_KERNEL
+libpath_manager_la_SOURCES += netlink_pm_upstream.c
+else
+libpath_manager_la_SOURCES += netlink_pm_mptcp_org.c
+endif
+
 libpath_manager_la_LIBADD =			\
 	$(top_builddir)/lib/libmptcpd.la	\
 	$(ELL_LIBS) $(CODE_COVERAGE_LIBS)