netlink: add a basic rtnetlink parser of neigh messages

* rtnl_neigh.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* netlink_route.h (decode_ndmsg, decode_rtm_getneigh): New prototypes.
* configure.ac (AC_CHECK_HEADERS): Add linux/neighbour.h.
* netlink_route.c (route_decoders): Add RTM_DELNEIGH, RTM_DELNEIGH,
and RTM_NEWNEIGH.
* xlat/nda_types.in: New file.
* xlat/neighbor_cache_entry_flags.in: Likewise.
* xlat/neighbor_cache_entry_states.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_neigh.c	\
 	rtnl_route.c	\
 	rtnl_rule.c	\
 	sched.c		\

configure.ac

@@ -386,6 +386,7 @@ AC_CHECK_HEADERS(m4_normalize([
 	linux/ipc.h
 	linux/mmtimer.h
 	linux/msg.h
+	linux/neighbour.h
 	linux/netfilter/nfnetlink.h
 	linux/nsfs.h
 	linux/perf_event.h

netlink_route.c

@@ -69,7 +69,11 @@ static const netlink_route_decoder_t route_decoders[] = {
 
 	[RTM_DELRULE - RTM_BASE] = decode_fib_rule_hdr,
 	[RTM_GETRULE - RTM_BASE] = decode_fib_rule_hdr,
-	[RTM_NEWRULE - RTM_BASE] = decode_fib_rule_hdr
+	[RTM_NEWRULE - RTM_BASE] = decode_fib_rule_hdr,
+
+	[RTM_DELNEIGH - RTM_BASE] = decode_ndmsg,
+	[RTM_GETNEIGH - RTM_BASE] = decode_rtm_getneigh,
+	[RTM_NEWNEIGH - RTM_BASE] = decode_ndmsg
 };
 
 bool

netlink_route.h

@@ -42,6 +42,8 @@ route_decode_name(struct tcb *tcp,			\
 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_ndmsg);
+extern DECL_NETLINK_ROUTE_DECODER(decode_rtm_getneigh);
 extern DECL_NETLINK_ROUTE_DECODER(decode_rtmsg);
 
 #endif /* !STRACE_NETLINK_ROUTE_H */

rtnl_neigh.c

@@ -0,0 +1,77 @@
+/*
+ * 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_NEIGHBOUR_H
+# include <linux/neighbour.h>
+#endif
+
+#include "xlat/nda_types.h"
+#include "xlat/neighbor_cache_entry_flags.h"
+#include "xlat/neighbor_cache_entry_states.h"
+
+DECL_NETLINK_ROUTE_DECODER(decode_ndmsg)
+{
+	struct ndmsg ndmsg = { .ndm_family = family };
+	const size_t offset = sizeof(ndmsg.ndm_family);
+
+	PRINT_FIELD_XVAL("{", ndmsg, ndm_family, addrfams, "AF_???");
+
+	tprints(", ");
+	if (len >= sizeof(ndmsg)) {
+		if (!umoven_or_printaddr(tcp, addr + offset,
+					 sizeof(ndmsg) - offset,
+					 (void *) &ndmsg + offset)) {
+			PRINT_FIELD_IFINDEX("", ndmsg, ndm_ifindex);
+			PRINT_FIELD_FLAGS(", ", ndmsg, ndm_state,
+					  neighbor_cache_entry_states,
+					  "NUD_???");
+			PRINT_FIELD_FLAGS(", ", ndmsg, ndm_flags,
+					  neighbor_cache_entry_flags,
+					  "NTF_???");
+			PRINT_FIELD_XVAL(", ", ndmsg, ndm_type,
+					 nda_types, "NDA_???");
+		}
+	} else
+		tprints("...");
+	tprints("}");
+}
+
+DECL_NETLINK_ROUTE_DECODER(decode_rtm_getneigh)
+{
+	if (family == AF_BRIDGE)
+		decode_ifinfomsg(tcp, nlmsghdr, family, addr, len);
+	else
+		decode_ndmsg(tcp, nlmsghdr, family, addr, len);
+}

xlat/nda_types.in

@@ -0,0 +1,12 @@
+NDA_UNSPEC		0
+NDA_DST			1
+NDA_LLADDR		2
+NDA_CACHEINFO		3
+NDA_PROBES		4
+NDA_VLAN		5
+NDA_PORT		6
+NDA_VNI			7
+NDA_IFINDEX		8
+NDA_MASTER		9
+NDA_LINK_NETNSID	10
+NDA_SRC_VNI		11

xlat/neighbor_cache_entry_flags.in

@@ -0,0 +1,6 @@
+NTF_USE
+NTF_SELF
+NTF_MASTER
+NTF_PROXY
+NTF_EXT_LEARNED
+NTF_ROUTER

xlat/neighbor_cache_entry_states.in

@@ -0,0 +1,9 @@
+NUD_INCOMPLETE
+NUD_REACHABLE
+NUD_STALE
+NUD_DELAY
+NUD_PROBE
+NUD_FAILED
+NUD_NOARP
+NUD_PERMANENT
+NUD_NONE