Index: sbin/ifconfig/ifconfig.8
===================================================================
--- sbin/ifconfig/ifconfig.8
+++ sbin/ifconfig/ifconfig.8
@@ -28,7 +28,7 @@
 .\"     From: @(#)ifconfig.8	8.3 (Berkeley) 1/5/94
 .\" $FreeBSD$
 .\"
-.Dd December 17, 2019
+.Dd May 27, 2020
 .Dt IFCONFIG 8
 .Os
 .Sh NAME
@@ -56,6 +56,7 @@
 .Fl a
 .Op Fl L
 .Op Fl d
+.Op Fl g Ar groupname
 .Op Fl m
 .Op Fl u
 .Op Fl v
@@ -2915,9 +2916,17 @@
 to display information about all interfaces in the system.
 The
 .Fl d
-flag limits this to interfaces that are down, and
+flag limits this to interfaces that are down,
 .Fl u
-limits this to interfaces that are up.
+limits this to interfaces that are up, and
+.Fl -g
+limits this to members of specified group of interfaces.
+.Sy groupname
+may be prefixed with caret symbol (^) to list
+interfaces not belonging to specified group
+(see the
+.Sx EXAMPLES
+section).
 When no arguments are given,
 .Fl a
 is implied.
@@ -3041,6 +3050,9 @@
 .Pp
 Display inet and inet6 address subnet masks in CIDR notation
 .Dl # ifconfig -f inet:cidr,inet6:cidr
+.Pp
+Display interfaces that are up with the exception of loopack
+.Dl # ifconfig -a -u -g ^lo
 .Sh DIAGNOSTICS
 Messages indicating the specified interface does not exist, the
 requested address is unknown, or the user is not privileged and
Index: sbin/ifconfig/ifconfig.c
===================================================================
--- sbin/ifconfig/ifconfig.c
+++ sbin/ifconfig/ifconfig.c
@@ -105,6 +105,7 @@
 /* Formatter Strings */
 char	*f_inet, *f_inet6, *f_ether, *f_addr;
 
+static	bool group_member(const char *ifname, const char *match);
 static	int ifconfig(int argc, char *const *argv, int iscreate,
 		const struct afswtch *afp);
 static	void status(const struct afswtch *afp, const struct sockaddr_dl *sdl,
@@ -402,13 +403,15 @@
 	char options[1024], *cp, *envformat, *namecp = NULL;
 	struct ifa_queue q = TAILQ_HEAD_INITIALIZER(q);
 	struct ifa_order_elt *cur, *tmp;
-	const char *ifname;
+	const char *ifname, *matchgroup;
+
 	struct option *p;
 	size_t iflen;
 	int flags;
 
 	all = downonly = uponly = namesonly = noload = verbose = 0;
 	f_inet = f_inet6 = f_ether = f_addr = NULL;
+	matchgroup = NULL;
 
 	envformat = getenv("IFCONFIG_FORMAT");
 	if (envformat != NULL)
@@ -455,6 +458,14 @@
 		case 'v':
 			verbose++;
 			break;
+		case 'g':
+			if (all) {
+				if (optarg == NULL)
+					usage();
+				matchgroup = optarg;
+				break;
+			}
+			/* FALLTHROUGH */
 		default:
 			for (p = opts; p != NULL; p = p->next)
 				if (p->opt[0] == c) {
@@ -626,6 +637,8 @@
 			continue;
 		if (uponly && (ifa->ifa_flags & IFF_UP) == 0)
 			continue;
+		if (matchgroup && !group_member(ifa->ifa_name, matchgroup))
+			continue;
 		/*
 		 * Are we just listing the interfaces?
 		 */
@@ -670,6 +683,73 @@
 	exit(exit_code);
 }
 
+/*
+ * Returns true if an interface ifname should be listed based on rules:
+ * 1) ifname is a member of interface group;
+ * 2) ifname is NOT a member of interface group prepended
+ *     with caret: "^group".
+ */
+static bool
+group_member(const char *ifname, const char *match)
+{
+	static int		 sock = -1;
+
+	struct ifgroupreq	 ifgr;
+	struct ifg_req		*ifg;
+	int			 len;
+	bool			 findmatch;
+
+	/* Sanity checks. */
+	if (ifname == NULL || match == NULL)
+		return (false);
+
+	memset(&ifgr, 0, sizeof(ifgr));
+	strlcpy(ifgr.ifgr_name, ifname, IFNAMSIZ);
+
+	/* The socket is opened once. Let _exit() close it. */
+	if (sock == -1) {
+		sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
+    		if (sock == -1)
+            	    errx(1, "%s: socket(AF_LOCAL,SOCK_DGRAM)", __func__);
+	}
+
+	/* Determine amount of memory for the list of groups. */
+	if (ioctl(sock, SIOCGIFGROUP, (caddr_t)&ifgr) == -1) {
+		if (errno == EINVAL || errno == ENOTTY)
+			return (false);
+		else
+			errx(1, "%s: SIOCGIFGROUP", __func__);
+	}
+
+	/* Obtain the list of groups. */
+	len = ifgr.ifgr_len;
+	ifgr.ifgr_groups =
+	    (struct ifg_req *)calloc(len / sizeof(*ifg), sizeof(*ifg));
+
+	if (ifgr.ifgr_groups == NULL)
+		errx(1, "%s: no memory", __func__);
+	if (ioctl(sock, SIOCGIFGROUP, (caddr_t)&ifgr) == -1)
+		errx(1, "%s: SIOCGIFGROUP", __func__);
+
+	/* Perform matching. */
+	findmatch = true;
+	if (match[0] == '^') {
+		findmatch = false;
+		match++;
+
+		/* Sanity check. */
+		if (!*match)
+			return (false);
+	}
+
+	for (ifg = ifgr.ifgr_groups; ifg && len >= sizeof(*ifg); ifg++) {
+		if (strcmp(ifg->ifgrq_group, match) == 0)
+		    	return (findmatch);
+		len -= sizeof(*ifg);
+	}
+	return (!findmatch);
+}
+
 static struct afswtch *afs = NULL;
 
 void