netlink: add a basic rtnetlink parser of rule messages

* defs.h (routing_table_ids): New xlat prototype.
* rtnl_rule.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* defs.h (ip_type_of_services, routing_table_ids): New xlat prototypes.
* netlink_route.h (decode_fib_rule_hdr): New prototype.
* configure.ac (AC_CHECK_HEADERS): Add linux/fib_rules.h.
* netlink_route.c (route_decoders): Add RTM_DELRULE, RTM_GETRULE,
and RTM_NEWRULE.
* xlat/fib_rule_actions.in: New file.
* xlat/fib_rule_flags.in: Likewise.

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

Makefile.am

@@ -250,6 +250,7 @@ strace_SOURCES =	\
 	rtnl_addr.c	\
 	rtnl_link.c	\
 	rtnl_route.c	\
+	rtnl_rule.c	\
 	sched.c		\
 	sched_attr.h	\
 	scsi.c		\

configure.ac

@@ -377,6 +377,7 @@ AC_CHECK_HEADERS(m4_normalize([
 	linux/dm-ioctl.h
 	linux/dqblk_xfs.h
 	linux/falloc.h
+	linux/fib_rules.h
 	linux/fiemap.h
 	linux/genetlink.h
 	linux/hiddev.h

defs.h

@@ -292,6 +292,7 @@ extern const struct xlat ethernet_protocols[];
 extern const struct xlat evdev_abs[];
 extern const struct xlat iffflags[];
 extern const struct xlat inet_protocols[];
+extern const struct xlat ip_type_of_services[];
 extern const struct xlat msg_flags[];
 extern const struct xlat netlink_protocols[];
 extern const struct xlat nl_route_types[];
@@ -299,6 +300,7 @@ 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 routing_table_ids[];
 extern const struct xlat setns_types[];
 extern const struct xlat sg_io_info[];
 extern const struct xlat socketlayers[];

netlink_route.c

@@ -65,7 +65,11 @@ static const netlink_route_decoder_t route_decoders[] = {
 
 	[RTM_DELROUTE - RTM_BASE] = decode_rtmsg,
 	[RTM_GETROUTE - RTM_BASE] = decode_rtmsg,
-	[RTM_NEWROUTE - RTM_BASE] = decode_rtmsg
+	[RTM_NEWROUTE - RTM_BASE] = decode_rtmsg,
+
+	[RTM_DELRULE - RTM_BASE] = decode_fib_rule_hdr,
+	[RTM_GETRULE - RTM_BASE] = decode_fib_rule_hdr,
+	[RTM_NEWRULE - RTM_BASE] = decode_fib_rule_hdr
 };
 
 bool

netlink_route.h

@@ -39,6 +39,7 @@ route_decode_name(struct tcb *tcp,			\
 		  unsigned int len)			\
 /* End of DECL_NETLINK_ROUTE_DECODER definition. */
 
+extern DECL_NETLINK_ROUTE_DECODER(decode_fib_rule_hdr);
 extern DECL_NETLINK_ROUTE_DECODER(decode_ifaddrmsg);
 extern DECL_NETLINK_ROUTE_DECODER(decode_ifinfomsg);
 extern DECL_NETLINK_ROUTE_DECODER(decode_rtmsg);

rtnl_rule.c

@@ -0,0 +1,78 @@
+/*
+ * 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 "netlink.h"
+#include <linux/rtnetlink.h>
+#ifdef HAVE_LINUX_FIB_RULES_H
+# include <linux/fib_rules.h>
+#endif
+
+#include "xlat/fib_rule_actions.h"
+#include "xlat/fib_rule_flags.h"
+
+DECL_NETLINK_ROUTE_DECODER(decode_fib_rule_hdr)
+{
+	/*
+	 * struct rtmsg and struct fib_rule_hdr are essentially
+	 * the same structure, use struct rtmsg but treat it as
+	 * struct fib_rule_hdr.
+	 */
+	struct rtmsg msg = { .rtm_family = family };
+	const size_t offset = sizeof(msg.rtm_family);
+
+	tprints("{family=");
+	printxval(addrfams, msg.rtm_family, "AF_???");
+
+	tprints(", ");
+	if (len >= sizeof(msg)) {
+		if (!umoven_or_printaddr(tcp, addr + offset,
+					 sizeof(msg) - offset,
+					 (void *) &msg + offset)) {
+			tprintf("dst_len=%u, src_len=%u",
+				msg.rtm_dst_len, msg.rtm_src_len);
+			tprints(", tos=");
+			printflags(ip_type_of_services, msg.rtm_tos,
+				   "IPTOS_TOS_???");
+			tprints(", table=");
+			printxval(routing_table_ids, msg.rtm_table, NULL);
+			tprints(", action=");
+			printxval(fib_rule_actions, msg.rtm_type, "FR_ACT_???");
+			tprints(", flags=");
+			printflags(fib_rule_flags, msg.rtm_flags,
+				   "FIB_RULE_???");
+		}
+	} else
+		tprints("...");
+	tprints("}");
+}

xlat/fib_rule_actions.in

@@ -0,0 +1,9 @@
+FR_ACT_UNSPEC		0
+FR_ACT_TO_TBL		1
+FR_ACT_GOTO		2
+FR_ACT_NOP		3
+FR_ACT_RES3		4
+FR_ACT_RES4		5
+FR_ACT_BLACKHOLE	6
+FR_ACT_UNREACHABLE	7
+FR_ACT_PROHIBIT		8

xlat/fib_rule_flags.in

@@ -0,0 +1,6 @@
+FIB_RULE_PERMANENT
+FIB_RULE_INVERT
+FIB_RULE_UNRESOLVED
+FIB_RULE_IIF_DETACHED
+FIB_RULE_OIF_DETACHED
+FIB_RULE_FIND_SADDR