rtnl_neigh: implement NDA_FDB_EXT_ATTRS decoding

* src/xlat/fdb_notify_flags.in: New file.
* src/xlat/rtnl_neigh_fdb_ext_attrs.in: Likewise.
* src/rtnl_neigh.c: Include "xlat/fdb_notify_flags.h",
"xlat/rtnl_neigh_fdb_ext_attrs.h".
(decode_fdb_notify_flags, decode_nda_fdb_ext_attrs): New functions.
(nda_fdb_ext_attrs_nla_decoders): New decoder array.
(ndmsg_nla_decoders) <[NDA_FDB_EXT_ATTRS]>: New entry, calls
decode_nda_fdb_ext_attrs.
* tests/nlattr_ndmsg.c: Add checks.
* NEWS: Mention it.

5 files changed, 103 insertions, 3 deletions

diff --git a/NEWS b/NEWS
index 58597e451..c4ecb52c2 100644
--- a/NEWS
+++ b/NEWS
@@ -8,8 +8,8 @@ Noteworthy changes in release ?.?? (????-??-??)
 
 * Improvements
   * Implemented printing of Unix socket sun_path field's SELinux context.
-  * Implemented decoding of IFLA_TSO_MAX_SIZE and IFLA_TSO_MAX_SEGS netlink
-    attributes.
+  * Implemented decoding of IFLA_TSO_MAX_SIZE, IFLA_TSO_MAX_SEGS,
+    and NDA_FDB_EXT_ATTRS netlink attributes.
   * Improved decoding of INET_DIAG_LOCALS, INET_DIAG_MD5SIG, INET_DIAG_PEERS,
     INET_DIAG_PROTOCOL, INET_DIAG_REQ_PROTOCOL, INET_DIAG_SHUTDOWN,
     INET_DIAG_SK_BPF_STORAGES, INET_DIAG_SOCKOPT, and INET_DIAG_ULP_INFO
diff --git a/src/rtnl_neigh.c b/src/rtnl_neigh.c
index aea1240bf..28dd1d59b 100644
--- a/src/rtnl_neigh.c
+++ b/src/rtnl_neigh.c
@@ -14,9 +14,11 @@
 #include "netlink.h"
 #include <linux/neighbour.h>
 
+#include "xlat/fdb_notify_flags.h"
 #include "xlat/neighbor_cache_entry_flags.h"
 #include "xlat/neighbor_cache_entry_states.h"
 #include "xlat/rtnl_neigh_attrs.h"
+#include "xlat/rtnl_neigh_fdb_ext_attrs.h"
 
 static bool
 decode_neigh_addr(struct tcb *const tcp,
@@ -56,6 +58,39 @@ decode_nda_cacheinfo(struct tcb *const tcp,
 	return true;
 }
 
+static bool
+decode_fdb_notify_flags(struct tcb *const tcp,
+		        const kernel_ulong_t addr,
+		        const unsigned int len,
+		        const void *const opaque_data)
+{
+	static const struct decode_nla_xlat_opts opts = {
+		fdb_notify_flags, "FDB_NOTIFY_???",
+		.size = 1,
+	};
+
+	return decode_nla_flags(tcp, addr, len, &opts);
+}
+
+static const nla_decoder_t nda_fdb_ext_attrs_nla_decoders[] = {
+	[NFEA_UNSPEC]		= NULL,
+	[NFEA_ACTIVITY_NOTIFY]	= decode_fdb_notify_flags,
+	[NFEA_DONT_REFRESH]	= NULL, /* flag attr, no payload is expected */
+};
+
+static bool
+decode_nda_fdb_ext_attrs(struct tcb *const tcp,
+			 const kernel_ulong_t addr,
+			 const unsigned int len,
+			 const void *const opaque_data)
+{
+	decode_nlattr(tcp, addr, len, rtnl_neigh_fdb_ext_attrs,
+		      "NFEA_???", ARRSZ_PAIR(nda_fdb_ext_attrs_nla_decoders),
+		      opaque_data);
+
+	return true;
+}
+
 static const nla_decoder_t ndmsg_nla_decoders[] = {
 	[NDA_DST]		= decode_neigh_addr,
 	[NDA_LLADDR]		= decode_nla_hwaddr_nofamily,
@@ -70,6 +105,7 @@ static const nla_decoder_t ndmsg_nla_decoders[] = {
 	[NDA_SRC_VNI]		= NULL,
 	[NDA_PROTOCOL]		= decode_nla_u8,
 	[NDA_NH_ID]		= decode_nla_u32,
+	[NDA_FDB_EXT_ATTRS]	= decode_nda_fdb_ext_attrs,
 };
 
 DECL_NETLINK_ROUTE_DECODER(decode_ndmsg)
diff --git a/src/xlat/fdb_notify_flags.in b/src/xlat/fdb_notify_flags.in
new file mode 100644
index 000000000..b9181496d
--- /dev/null
+++ b/src/xlat/fdb_notify_flags.in
@@ -0,0 +1,2 @@
+FDB_NOTIFY_BIT		(1 << 0)
+FDB_NOTIFY_INACTIVE_BIT	(1 << 1)
diff --git a/src/xlat/rtnl_neigh_fdb_ext_attrs.in b/src/xlat/rtnl_neigh_fdb_ext_attrs.in
new file mode 100644
index 000000000..24b52286e
--- /dev/null
+++ b/src/xlat/rtnl_neigh_fdb_ext_attrs.in
@@ -0,0 +1,5 @@
+#enum
+#value_indexed
+NFEA_UNSPEC		0
+NFEA_ACTIVITY_NOTIFY	1
+NFEA_DONT_REFRESH	2
diff --git a/tests/nlattr_ndmsg.c b/tests/nlattr_ndmsg.c
index 77694c22e..85ec7c746 100644
--- a/tests/nlattr_ndmsg.c
+++ b/tests/nlattr_ndmsg.c
@@ -15,6 +15,8 @@
 #include <linux/neighbour.h>
 #include <linux/rtnetlink.h>
 
+static const unsigned int hdrlen = sizeof(struct ndmsg);
+
 static void
 init_ndmsg(struct nlmsghdr *const nlh, const unsigned int msg_len)
 {
@@ -46,13 +48,32 @@ print_ndmsg(const unsigned int msg_len)
 	       msg_len);
 }
 
+static void
+init_ndmsg_nfea(struct nlmsghdr *const nlh, const unsigned int msg_len)
+{
+	init_ndmsg(nlh, msg_len);
+
+	struct nlattr *nla = NLMSG_ATTR(nlh, hdrlen);
+	SET_STRUCT(struct nlattr, nla,
+		.nla_len = msg_len - NLMSG_SPACE(hdrlen),
+		.nla_type = NDA_FDB_EXT_ATTRS,
+	);
+}
+
+static void
+print_ndmsg_nfea(const unsigned int msg_len)
+{
+	print_ndmsg(msg_len);
+	printf(", [{nla_len=%u, nla_type=NDA_FDB_EXT_ATTRS}",
+	       msg_len - NLMSG_SPACE(hdrlen));
+}
+
 int
 main(void)
 {
 	skip_if_unavailable("/proc/self/fd/");
 
 	const int fd = create_nl_socket(NETLINK_ROUTE);
-	const unsigned int hdrlen = sizeof(struct ndmsg);
 	void *nlh0 = midtail_alloc(NLMSG_SPACE(hdrlen),
 				   NLA_HDRLEN + sizeof(struct nda_cacheinfo));
 
@@ -110,6 +131,42 @@ main(void)
 		    for (unsigned int i = 0; i < sizeof(mac); ++i)
 			printf("%s%02x", i ? ":" : "", mac[i]));
 
+	/* NDA_FDB_EXT_ATTRS: unknown, undecoded */
+	static const struct strval16 nfea_unk_attrs[] = {
+		{ ENUM_KNOWN(0, NFEA_UNSPEC) },
+		{ ENUM_KNOWN(0x2, NFEA_DONT_REFRESH) },
+		{ ARG_XLAT_UNKNOWN(0x3, "NFEA_???") },
+		{ ARG_XLAT_UNKNOWN(0x1ace, "NFEA_???") },
+	};
+	static const uint32_t dummy = BE_LE(0xbadc0ded, 0xed0ddcba);
+
+	for (size_t i = 0; i < ARRAY_SIZE(nfea_unk_attrs); i++) {
+		TEST_NESTED_NLATTR_(fd, nlh0, hdrlen,
+				    init_ndmsg_nfea, print_ndmsg_nfea,
+				    nfea_unk_attrs[i].val,
+				    nfea_unk_attrs[i].str,
+				    sizeof(dummy), &dummy, sizeof(dummy), 1,
+				    printf("\"\\xba\\xdc\\x0d\\xed\""));
+	}
+
+	/* NDA_FDB_EXT_ATTRS: NFEA_ACTIVITY_NOTIFY */
+	static const struct strval8 fan_flags[] = {
+		{ ARG_STR(0) },
+		{ ARG_XLAT_KNOWN(0x1, "FDB_NOTIFY_BIT") },
+		{ ARG_XLAT_KNOWN(0xef, "FDB_NOTIFY_BIT"
+				       "|FDB_NOTIFY_INACTIVE_BIT|0xec") },
+		{ ARG_XLAT_UNKNOWN(0xfc, "FDB_NOTIFY_???") },
+	};
+
+	for (size_t i = 0; i < ARRAY_SIZE(fan_flags); i++) {
+		TEST_NESTED_NLATTR_(fd, nlh0, hdrlen,
+				    init_ndmsg_nfea, print_ndmsg_nfea,
+				    NFEA_ACTIVITY_NOTIFY,
+				    "NFEA_ACTIVITY_NOTIFY",
+				    1, &fan_flags[i].val, 1, 1,
+				    printf("%s", fan_flags[i].str));
+	}
+
 	puts("+++ exited with 0 +++");
 	return 0;
 }