Index: ifconfig.8
===================================================================
--- ifconfig.8
+++ ifconfig.8
@@ -28,7 +28,7 @@
 .\"     From: @(#)ifconfig.8	8.3 (Berkeley) 1/5/94
 .\" $FreeBSD$
 .\"
-.Dd December 17, 2019
+.Dd May 31, 2020
 .Dt IFCONFIG 8
 .Os
 .Sh NAME
@@ -56,6 +56,7 @@
 .Fl a
 .Op Fl L
 .Op Fl d
+.Op Fl [gG] Ar groupname
 .Op Fl m
 .Op Fl u
 .Op Fl v
@@ -2915,9 +2916,20 @@
 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,
+.Fl g
+limits this to members of specified group of interfaces, and
+.Fl G
+excludes members of specified group from the list.
+Both
+.Fl g
+and
+.Fl G
+flags may be specified to apply both conditions.
+.Sy groupname
+may contain shell patterns in which case it should be quoted.
 When no arguments are given,
 .Fl a
 is implied.
@@ -3041,6 +3053,9 @@
 .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: ifconfig.c
===================================================================
--- ifconfig.c
+++ ifconfig.c
@@ -63,6 +63,7 @@
 #include <arpa/inet.h>
 #include <netdb.h>
 
+#include <fnmatch.h>
 #include <ifaddrs.h>
 #include <ctype.h>
 #include <err.h>
@@ -105,6 +106,8 @@
 /* Formatter Strings */
 char	*f_inet, *f_inet6, *f_ether, *f_addr;
 
+static	bool group_member(const char *ifname, const char *match,
+		const char *nomatch);
 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 +405,14 @@
 	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, *nogroup;
 	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 = nogroup = NULL;
 
 	envformat = getenv("IFCONFIG_FORMAT");
 	if (envformat != NULL)
@@ -421,7 +425,7 @@
 	atexit(printifnamemaybe);
 
 	/* Parse leading line options */
-	strlcpy(options, "f:adklmnuv", sizeof(options));
+	strlcpy(options, "G:adf:klmnuv", sizeof(options));
 	for (p = opts; p != NULL; p = p->next)
 		strlcat(options, p->opt, sizeof(options));
 	while ((c = getopt(argc, argv, options)) != -1) {
@@ -437,6 +441,11 @@
 				usage();
 			setformat(optarg);
 			break;
+		case 'G':
+			if (optarg == NULL || all == 0)
+				usage();
+			nogroup = optarg;
+			break;
 		case 'k':
 			printkeys++;
 			break;
@@ -455,6 +464,14 @@
 		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 +643,8 @@
 			continue;
 		if (uponly && (ifa->ifa_flags & IFF_UP) == 0)
 			continue;
+		if (!group_member(ifa->ifa_name, matchgroup, nogroup))
+			continue;
 		/*
 		 * Are we just listing the interfaces?
 		 */
@@ -670,6 +689,73 @@
 	exit(exit_code);
 }
 
+/*
+ * Returns true if an interface should be listed because any its groups
+ * matches shell pattern "match" and none of groups matches pattern "nomatch".
+ * If any pattern is NULL, corresponding condition is skipped.
+ */
+static bool
+group_member(const char *ifname, const char *match, const char *nomatch)
+{
+	static int		 sock = -1;
+
+	struct ifgroupreq	 ifgr;
+	struct ifg_req		*ifg;
+	int			 len;
+	bool			 matched, nomatched;
+
+	/* Sanity checks. */
+	if (match == NULL && nomatch == NULL)
+		return (true);
+	if (ifname == 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. */
+	matched = false;
+	nomatched = true;
+	for (ifg = ifgr.ifgr_groups; ifg && len >= sizeof(*ifg); ifg++) {
+		len -= sizeof(struct ifg_req);
+		if (match)
+			matched |= !fnmatch(match, ifg->ifgrq_group, 0);
+		if (nomatch)
+			nomatched &= fnmatch(nomatch, ifg->ifgrq_group, 0);
+	}
+
+	if (match && !nomatch)
+		return (matched);
+	if (!match && nomatch)
+		return (nomatched);
+	return (matched && nomatched);
+}
+
 static struct afswtch *afs = NULL;
 
 void