netlink: add a basic rtnetlink parser of route messages

* defs.h (routing_scopes): New xlat prototype.
* rtnl_route.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* netlink_route.h (decode_rtmsg): New prototype.
* netlink_route.c (route_decoders): Add RTM_DELROUTE, RTM_GETROUTE,
and RTM_NEWROUTE.
* xlat/ip_type_of_services.in: New file.
* xlat/routing_flags.in: Likewise.
* xlat/routing_protocols.in: Likewise.
* xlat/routing_table_ids.in: Likewise.
* xlat/routing_types.in: Likewise.

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

Makefile.am

@@ -249,6 +249,7 @@ strace_SOURCES =	\
 	rtc.c		\
 	rtnl_addr.c	\
 	rtnl_link.c	\
+	rtnl_route.c	\
 	sched.c		\
 	sched_attr.h	\
 	scsi.c		\

defs.h

@@ -298,6 +298,7 @@ extern const struct xlat nl_route_types[];
 extern const struct xlat open_access_modes[];
 extern const struct xlat open_mode_flags[];
 extern const struct xlat resource_flags[];
+extern const struct xlat routing_scopes[];
 extern const struct xlat setns_types[];
 extern const struct xlat sg_io_info[];
 extern const struct xlat socketlayers[];

netlink_route.c

@@ -61,7 +61,11 @@ static const netlink_route_decoder_t route_decoders[] = {
 	[RTM_GETADDR - RTM_BASE] = decode_ifaddrmsg,
 	[RTM_GETANYCAST - RTM_BASE] = decode_ifaddrmsg,
 	[RTM_GETMULTICAST - RTM_BASE] = decode_ifaddrmsg,
-	[RTM_NEWADDR - RTM_BASE] = decode_ifaddrmsg
+	[RTM_NEWADDR - RTM_BASE] = decode_ifaddrmsg,
+
+	[RTM_DELROUTE - RTM_BASE] = decode_rtmsg,
+	[RTM_GETROUTE - RTM_BASE] = decode_rtmsg,
+	[RTM_NEWROUTE - RTM_BASE] = decode_rtmsg
 };
 
 bool

netlink_route.h

@@ -41,5 +41,6 @@ route_decode_name(struct tcb *tcp,			\
 
 extern DECL_NETLINK_ROUTE_DECODER(decode_ifaddrmsg);
 extern DECL_NETLINK_ROUTE_DECODER(decode_ifinfomsg);
+extern DECL_NETLINK_ROUTE_DECODER(decode_rtmsg);
 
 #endif /* !STRACE_NETLINK_ROUTE_H */

rtnl_route.c

@@ -0,0 +1,74 @@
+/*
+ * 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"
+#include "netlink_route.h"
+#include "print_fields.h"
+
+#include <linux/ip.h>
+#include "netlink.h"
+#include <linux/rtnetlink.h>
+
+#include "xlat/ip_type_of_services.h"
+#include "xlat/routing_flags.h"
+#include "xlat/routing_protocols.h"
+#include "xlat/routing_table_ids.h"
+#include "xlat/routing_types.h"
+
+DECL_NETLINK_ROUTE_DECODER(decode_rtmsg)
+{
+	struct rtmsg rtmsg = { .rtm_family = family };
+	const size_t offset = sizeof(rtmsg.rtm_family);
+
+	PRINT_FIELD_XVAL("{", rtmsg, rtm_family, addrfams, "AF_???");
+
+	tprints(", ");
+	if (len >= sizeof(rtmsg)) {
+		if (!umoven_or_printaddr(tcp, addr + offset,
+					 sizeof(rtmsg) - offset,
+					 (void *) &rtmsg + offset)) {
+			PRINT_FIELD_U("", rtmsg, rtm_dst_len);
+			PRINT_FIELD_U(", ", rtmsg, rtm_src_len);
+			PRINT_FIELD_FLAGS(", ", rtmsg, rtm_tos,
+					  ip_type_of_services, "IPTOS_TOS_???");
+			PRINT_FIELD_XVAL(", ", rtmsg, rtm_table,
+					 routing_table_ids, NULL);
+			PRINT_FIELD_XVAL(", ", rtmsg, rtm_protocol,
+					 routing_protocols, "RTPROT_???");
+			PRINT_FIELD_XVAL(", ", rtmsg, rtm_scope,
+					 routing_scopes, NULL);
+			PRINT_FIELD_XVAL(", ", rtmsg, rtm_type,
+					 routing_types, "RTN_???");
+			PRINT_FIELD_FLAGS(", ", rtmsg, rtm_flags,
+					  routing_flags, "RTM_F_???");
+		}
+	} else
+		tprints("...");
+	tprints("}");
+}

xlat/ip_type_of_services.in

@@ -0,0 +1,4 @@
+IPTOS_LOWDELAY
+IPTOS_THROUGHPUT
+IPTOS_RELIABILITY
+IPTOS_MINCOST

xlat/routing_flags.in

@@ -0,0 +1,5 @@
+RTM_F_NOTIFY
+RTM_F_CLONED
+RTM_F_EQUALIZE
+RTM_F_PREFIX
+RTM_F_LOOKUP_TABLE

xlat/routing_protocols.in

@@ -0,0 +1,16 @@
+RTPROT_UNSPEC
+RTPROT_REDIRECT
+RTPROT_KERNEL
+RTPROT_BOOT
+RTPROT_STATIC
+RTPROT_GATED
+RTPROT_RA
+RTPROT_MRT
+RTPROT_ZEBRA
+RTPROT_BIRD
+RTPROT_DNROUTED
+RTPROT_XORP
+RTPROT_NTK
+RTPROT_DHCP
+RTPROT_MROUTED
+RTPROT_BABEL

xlat/routing_table_ids.in

@@ -0,0 +1,5 @@
+RT_TABLE_UNSPEC		0
+RT_TABLE_COMPAT		252
+RT_TABLE_DEFAULT	253
+RT_TABLE_MAIN		254
+RT_TABLE_LOCAL		255

xlat/routing_types.in

@@ -0,0 +1,12 @@
+RTN_UNSPEC	0
+RTN_UNICAST	1
+RTN_LOCAL	2
+RTN_BROADCAST	3
+RTN_ANYCAST	4
+RTN_MULTICAST	5
+RTN_BLACKHOLE	6
+RTN_UNREACHABLE	7
+RTN_PROHIBIT	8
+RTN_THROW	9
+RTN_NAT		10
+RTN_XRESOLVE	11