netlink: add a basic rtnetlink parser of netconf messages

* rtnl_netconf.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* netlink_route.h (decode_netconfmsg): New prototype.
* configure.ac (AC_CHECK_TYPES): Check for struct netconfmsg
in <linux/netconf.h>.
* netlink_route.c (route_decoders): Add RTM_GETNETCONF
and RTM_NEWNETCONF.

Co-authored-by: Fabien Siron <fabien.siron@epita.fr>

Makefile.am

@@ -253,6 +253,7 @@ strace_SOURCES =	\
 	rtnl_link.c	\
 	rtnl_neigh.c	\
 	rtnl_neightbl.c	\
+	rtnl_netconf.c	\
 	rtnl_route.c	\
 	rtnl_rule.c	\
 	rtnl_tc.c	\

configure.ac

@@ -445,6 +445,7 @@ AC_CHECK_HEADERS([linux/bpf.h], [
 
 AC_CHECK_TYPES([struct dcbmsg],,, [#include <linux/dcbnl.h>])
 AC_CHECK_TYPES([struct ifaddrlblmsg],,, [#include <linux/if_addrlabel.h>])
+AC_CHECK_TYPES([struct netconfmsg],,, [#include <linux/netconf.h>])
 
 AC_CHECK_TYPES([struct statfs], [
 	AC_CHECK_MEMBERS([struct statfs.f_frsize],,, [#include <linux/types.h>

netlink_route.c

@@ -101,7 +101,13 @@ static const netlink_route_decoder_t route_decoders[] = {
 
 #ifdef HAVE_STRUCT_DCBMSG
 	[RTM_GETDCB - RTM_BASE] = decode_dcbmsg,
-	[RTM_SETDCB - RTM_BASE] = decode_dcbmsg
+	[RTM_SETDCB - RTM_BASE] = decode_dcbmsg,
+#endif
+
+#ifdef HAVE_STRUCT_NETCONFMSG
+	[RTM_DELNETCONF - RTM_BASE] = decode_netconfmsg,
+	[RTM_GETNETCONF - RTM_BASE] = decode_netconfmsg,
+	[RTM_NEWNETCONF - RTM_BASE] = decode_netconfmsg
 #endif
 };
 

netlink_route.h

@@ -46,6 +46,7 @@ extern DECL_NETLINK_ROUTE_DECODER(decode_ifaddrmsg);
 extern DECL_NETLINK_ROUTE_DECODER(decode_ifinfomsg);
 extern DECL_NETLINK_ROUTE_DECODER(decode_ndmsg);
 extern DECL_NETLINK_ROUTE_DECODER(decode_ndtmsg);
+extern DECL_NETLINK_ROUTE_DECODER(decode_netconfmsg);
 extern DECL_NETLINK_ROUTE_DECODER(decode_rtm_getneigh);
 extern DECL_NETLINK_ROUTE_DECODER(decode_rtmsg);
 extern DECL_NETLINK_ROUTE_DECODER(decode_tcamsg);

rtnl_netconf.c

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2016 Fabien Siron <fabien.siron@epita.fr>
+ * Copyright (c) 2017 JingPiao Chen <chenjingpiao@gmail.com>
+ * Copyright (c) 2016-2017 The strace developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "defs.h"
+
+#ifdef HAVE_STRUCT_NETCONFMSG
+
+# include "netlink_route.h"
+# include "print_fields.h"
+
+# include <linux/netconf.h>
+
+DECL_NETLINK_ROUTE_DECODER(decode_netconfmsg)
+{
+	struct netconfmsg ncm = { .ncm_family = family };
+
+	PRINT_FIELD_XVAL("{", ncm, ncm_family, addrfams, "AF_???");
+	tprints("}");
+}
+
+#endif