[PATCH v2 4/7] rtnl_neigh: decode ndmsg netlink attributes

[JingPiao Chen]

* nlattr.c: Include <netinet/in.h> and <arpa/inet.h>.
(decode_nla_be16): New function.
* nlattr.h (decode_nla_be16): New prototype.
* rtnl_neigh.c (decode_neigh_addr,
decode_nda_cacheinfo): New functions.
(ndmsg_nla_decoders): New array.
(decode_ndmsg): Use it.
---
 nlattr.c     | 18 ++++++++++++++++++
 nlattr.h     |  1 +
 rtnl_neigh.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/nlattr.c b/nlattr.c
index 396db35..e67339c 100644
--- a/nlattr.c
+++ b/nlattr.c
@@ -33,6 +33,8 @@
 
 #include <endian.h>
 
+#include <netinet/in.h>
+#include <arpa/inet.h>
 #include <linux/sock_diag.h>
 
 static bool
@@ -224,6 +226,22 @@ decode_nla_ifindex(struct tcb *const tcp,
 }
 
 bool
+decode_nla_be16(struct tcb *const tcp,
+		const kernel_ulong_t addr,
+		const unsigned int len,
+		const void *const opaque_data)
+{
+	uint16_t num;
+
+	if (len < sizeof(num))
+		return false;
+	else if (!umove_or_printaddr(tcp, addr, &num))
+		tprintf("htons(%u)", ntohs(num));
+
+	return true;
+}
+
+bool
 decode_nla_be64(struct tcb *const tcp,
 		const kernel_ulong_t addr,
 		const unsigned int len,
diff --git a/nlattr.h b/nlattr.h
index db1fd69..09c233e 100644
--- a/nlattr.h
+++ b/nlattr.h
@@ -56,6 +56,7 @@ DECL_NLA(s8);
 DECL_NLA(s16);
 DECL_NLA(s32);
 DECL_NLA(s64);
+DECL_NLA(be16);
 DECL_NLA(be64);
 DECL_NLA(str);
 DECL_NLA(strn);
diff --git a/rtnl_neigh.c b/rtnl_neigh.c
index 7191ecb..0eaadc5 100644
--- a/rtnl_neigh.c
+++ b/rtnl_neigh.c
@@ -42,6 +42,54 @@
 #include "xlat/neighbor_cache_entry_states.h"
 #include "xlat/rtnl_neigh_attrs.h"
 
+static bool
+decode_neigh_addr(struct tcb *const tcp,
+		  const kernel_ulong_t addr,
+		  const unsigned int len,
+		  const void *const opaque_data)
+{
+	const struct ndmsg *const ndmsg = opaque_data;
+
+	decode_inet_addr(tcp, addr, len, ndmsg->ndm_family, NULL);
+
+	return true;
+}
+
+static bool
+decode_nda_cacheinfo(struct tcb *const tcp,
+		     const kernel_ulong_t addr,
+		     const unsigned int len,
+		     const void *const opaque_data)
+{
+	struct nda_cacheinfo ci;
+
+	if (len < sizeof(ci))
+		return false;
+	else if (!umove_or_printaddr(tcp, addr, &ci)) {
+		PRINT_FIELD_U("{", ci, ndm_confirmed);
+		PRINT_FIELD_U(", ", ci, ndm_used);
+		PRINT_FIELD_U(", ", ci, ndm_updated);
+		PRINT_FIELD_U(", ", ci, ndm_refcnt);
+		tprints("}");
+	}
+
+	return true;
+}
+
+static const nla_decoder_t ndmsg_nla_decoders[] = {
+	[NDA_DST]		= decode_neigh_addr,
+	[NDA_LLADDR]		= decode_neigh_addr,
+	[NDA_CACHEINFO]		= decode_nda_cacheinfo,
+	[NDA_PROBES]		= decode_nla_u32,
+	[NDA_VLAN]		= decode_nla_u16,
+	[NDA_PORT]		= decode_nla_be16,
+	[NDA_VNI]		= decode_nla_u32,
+	[NDA_IFINDEX]		= decode_nla_ifindex,
+	[NDA_MASTER]		= decode_nla_ifindex,
+	[NDA_LINK_NETNSID]	= decode_nla_u32,
+	[NDA_SRC_VNI]		= NULL,
+};
+
 DECL_NETLINK_ROUTE_DECODER(decode_ndmsg)
 {
 	struct ndmsg ndmsg = { .ndm_family = family };
@@ -74,7 +122,9 @@ DECL_NETLINK_ROUTE_DECODER(decode_ndmsg)
 	if (decode_nla && len > offset) {
 		tprints(", ");
 		decode_nlattr(tcp, addr + offset, len - offset,
-			      rtnl_neigh_attrs, "NDA_???", NULL, 0, NULL);
+			      rtnl_neigh_attrs, "NDA_???",
+			      ndmsg_nla_decoders,
+			      ARRAY_SIZE(ndmsg_nla_decoders), &ndmsg);
 	}
 }
 
-- 
2.7.4