netlink_unix_diag: implement UDIAG_SHOW_UID/UNIX_DIAG_UID decoding

... introduced by Linux kernel commit v5.3-rc1~140^2~467.

* linux/unix_diag.h (UDIAG_SHOW_UID, UNIX_DIAG_FIRST_UNUSED): New macro
constants.
(UNIX_DIAG_UID): New enum constant.
* xlat/unix_diag_attrs.in: Add UNIX_DIAG_UID.
* xlat/unix_diag_show.in: Add UDIAG_SHOW_UID.
* netlink_unix_diag.c (unix_diag_msg_nla_decoders): Handle
UNIX_DIAG_UID.
* NEWS: Mention this.
* tests/nlattr.c (test_nlattr, test_nla_type): Replace
UNIX_DIAG_SHUTDOWN + 1 with UNIX_DIAG_FIRST_UNUSED.

6 files changed, 14 insertions, 7 deletions

diff --git a/NEWS b/NEWS
index 93ae07f59..87c628347 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,7 @@ Noteworthy changes in release ?.? (????-??-??)
 
 * Improvements
   * Enhanced decoding of NETLINK_ROUTE protocol.
+  * Implemented decoding of UNIX_DIAG_UID netlink attribute.
   * Updated lists of BPF_*, ETH_*, KEYCTL_*, KVM_*, MAP_*, SO_*, TCP_*, V4L2_*,
     XDP_*, and *_MAGIC constants.
 
diff --git a/linux/unix_diag.h b/linux/unix_diag.h
index 1d15a0ce0..8f1f62b12 100644
--- a/linux/unix_diag.h
+++ b/linux/unix_diag.h
@@ -24,6 +24,7 @@ struct unix_diag_req {
 # define UDIAG_SHOW_ICONS	0x08
 # define UDIAG_SHOW_RQLEN	0x10
 # define UDIAG_SHOW_MEMINFO	0x20
+# define UDIAG_SHOW_UID		0x40
 
 struct unix_diag_msg {
 	uint8_t	 udiag_family;
@@ -42,6 +43,8 @@ enum {
 	UNIX_DIAG_RQLEN,
 	UNIX_DIAG_MEMINFO,
 	UNIX_DIAG_SHUTDOWN,
+	UNIX_DIAG_UID,
+	UNIX_DIAG_FIRST_UNUSED
 };
 
 struct unix_diag_vfs {
diff --git a/netlink_unix_diag.c b/netlink_unix_diag.c
index 5a9099634..920ac558c 100644
--- a/netlink_unix_diag.c
+++ b/netlink_unix_diag.c
@@ -119,7 +119,8 @@ static const nla_decoder_t unix_diag_msg_nla_decoders[] = {
 	[UNIX_DIAG_ICONS]	= decode_unix_diag_inode,
 	[UNIX_DIAG_RQLEN]	= decode_unix_diag_rqlen,
 	[UNIX_DIAG_MEMINFO]	= decode_nla_meminfo,
-	[UNIX_DIAG_SHUTDOWN]	= decode_nla_u8
+	[UNIX_DIAG_SHUTDOWN]	= decode_nla_u8,
+	[UNIX_DIAG_UID]		= decode_nla_uid
 };
 
 DECL_NETLINK_DIAG_DECODER(decode_unix_diag_msg)
diff --git a/tests/nlattr.c b/tests/nlattr.c
index 2c5927b23..204b3672c 100644
--- a/tests/nlattr.c
+++ b/tests/nlattr.c
@@ -105,7 +105,7 @@ test_nlattr(const int fd)
 	nla = NLMSG_ATTR(msg, sizeof(msg->udm));
 	*nla = (struct nlattr) {
 		.nla_len = NLA_HDRLEN + 4,
-		.nla_type = UNIX_DIAG_SHUTDOWN + 1
+		.nla_type = UNIX_DIAG_FIRST_UNUSED
 	};
 	memcpy(RTA_DATA(nla), "1234", 4);
 	rc = sendto(fd, msg, msg_len, MSG_DONTWAIT, NULL, 0);
@@ -116,7 +116,7 @@ test_nlattr(const int fd)
 	       ", nla_type=%#x /* UNIX_DIAG_??? */}"
 	       ", \"\\x31\\x32\\x33\\x34\"}}"
 	       ", %u, MSG_DONTWAIT, NULL, 0) = %s\n",
-	       fd, msg_len, nla->nla_len, UNIX_DIAG_SHUTDOWN + 1,
+	       fd, msg_len, nla->nla_len, UNIX_DIAG_FIRST_UNUSED,
 	       msg_len, sprintrc(rc));
 
 	/* print one struct nlattr and fetch fail second struct nlattr */
@@ -201,7 +201,7 @@ test_nlattr(const int fd)
 	for (i = 0; i < ABBREV_LEN; ++i) {
 		nla[i * 2] = (struct nlattr) {
 			.nla_len = NLA_HDRLEN * 2 - 1,
-			.nla_type = UNIX_DIAG_SHUTDOWN + 1 + i
+			.nla_type = UNIX_DIAG_FIRST_UNUSED + i
 		};
 		fill_memory_ex(&nla[i * 2 + 1], NLA_HDRLEN,
 			       '0' + i, '~' - '0' - i);
@@ -218,7 +218,7 @@ test_nlattr(const int fd)
 		if (i)
 			printf(", ");
 		printf("{{nla_len=%u, nla_type=%#x /* UNIX_DIAG_??? */}, ",
-		       nla->nla_len, UNIX_DIAG_SHUTDOWN + 1 + i);
+		       nla->nla_len, UNIX_DIAG_FIRST_UNUSED + i);
 		print_quoted_hex(&nla[i * 2 + 1], NLA_HDRLEN - 1);
 		printf("}");
 	}
@@ -286,7 +286,7 @@ test_nla_type(const int fd)
 	       ", %u, MSG_DONTWAIT, NULL, 0) = %s\n",
 	       fd, msg_len, nla->nla_len, msg_len, sprintrc(rc));
 
-	nla->nla_type = NLA_F_NESTED | (UNIX_DIAG_SHUTDOWN + 1);
+	nla->nla_type = NLA_F_NESTED | (UNIX_DIAG_FIRST_UNUSED);
 	rc = sendto(fd, msg, msg->nlh.nlmsg_len, MSG_DONTWAIT, NULL, 0);
 	printf("sendto(%d, {{len=%u, type=SOCK_DIAG_BY_FAMILY"
 	       ", flags=NLM_F_DUMP, seq=0, pid=0}, {udiag_family=AF_UNIX"
@@ -294,7 +294,7 @@ test_nla_type(const int fd)
 	       ", udiag_ino=0, udiag_cookie=[0, 0]}, {nla_len=%u"
 	       ", nla_type=NLA_F_NESTED|%#x /* UNIX_DIAG_??? */}}"
 	       ", %u, MSG_DONTWAIT, NULL, 0) = %s\n",
-	       fd, msg->nlh.nlmsg_len, nla->nla_len, UNIX_DIAG_SHUTDOWN + 1,
+	       fd, msg->nlh.nlmsg_len, nla->nla_len, UNIX_DIAG_FIRST_UNUSED,
 	       msg->nlh.nlmsg_len, sprintrc(rc));
 }
 
diff --git a/xlat/unix_diag_attrs.in b/xlat/unix_diag_attrs.in
index 4c3d9b2e3..fb2838cc9 100644
--- a/xlat/unix_diag_attrs.in
+++ b/xlat/unix_diag_attrs.in
@@ -6,3 +6,4 @@ UNIX_DIAG_ICONS
 UNIX_DIAG_RQLEN
 UNIX_DIAG_MEMINFO
 UNIX_DIAG_SHUTDOWN
+UNIX_DIAG_UID
diff --git a/xlat/unix_diag_show.in b/xlat/unix_diag_show.in
index c7dbdfbc6..5f50887fc 100644
--- a/xlat/unix_diag_show.in
+++ b/xlat/unix_diag_show.in
@@ -4,3 +4,4 @@ UDIAG_SHOW_PEER
 UDIAG_SHOW_ICONS
 UDIAG_SHOW_RQLEN
 UDIAG_SHOW_MEMINFO
+UDIAG_SHOW_UID