diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 38c680f..d11f1a7 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5082,6 +5082,11 @@
 				err = -EBUSY;
 			else if (!(nlmsg_flags & NLM_F_EXCL))
 				err = 0;
+		} else if (err == -ENOTEMPTY) {
+			/* ENOTEMPTY reports overlapping between this element
+			 * and an existing one.
+			 */
+			err = -EEXIST;
 		}
 		goto err_element_clash;
 	}
diff --git a/net/netfilter/nft_fwd_netdev.c b/net/netfilter/nft_fwd_netdev.c
index aba11c2..74f050b 100644
--- a/net/netfilter/nft_fwd_netdev.c
+++ b/net/netfilter/nft_fwd_netdev.c
@@ -28,6 +28,10 @@
 	struct nft_fwd_netdev *priv = nft_expr_priv(expr);
 	int oif = regs->data[priv->sreg_dev];
 
+	/* These are used by ifb only. */
+	pkt->skb->tc_redirected = 1;
+	pkt->skb->tc_from_ingress = 1;
+
 	nf_fwd_netdev_egress(pkt, oif);
 	regs->verdict.code = NF_STOLEN;
 }
@@ -190,6 +194,13 @@
 	return -1;
 }
 
+static int nft_fwd_validate(const struct nft_ctx *ctx,
+			    const struct nft_expr *expr,
+			    const struct nft_data **data)
+{
+	return nft_chain_validate_hooks(ctx->chain, (1 << NF_NETDEV_INGRESS));
+}
+
 static struct nft_expr_type nft_fwd_netdev_type;
 static const struct nft_expr_ops nft_fwd_neigh_netdev_ops = {
 	.type		= &nft_fwd_netdev_type,
@@ -197,6 +208,7 @@
 	.eval		= nft_fwd_neigh_eval,
 	.init		= nft_fwd_neigh_init,
 	.dump		= nft_fwd_neigh_dump,
+	.validate	= nft_fwd_validate,
 };
 
 static const struct nft_expr_ops nft_fwd_netdev_ops = {
@@ -205,6 +217,7 @@
 	.eval		= nft_fwd_netdev_eval,
 	.init		= nft_fwd_netdev_init,
 	.dump		= nft_fwd_netdev_dump,
+	.validate	= nft_fwd_validate,
 	.offload	= nft_fwd_netdev_offload,
 };
 
diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c
index 4fc0c92..ef7e8ad 100644
--- a/net/netfilter/nft_set_pipapo.c
+++ b/net/netfilter/nft_set_pipapo.c
@@ -1098,21 +1098,41 @@
 	struct nft_pipapo_field *f;
 	int i, bsize_max, err = 0;
 
+	if (nft_set_ext_exists(ext, NFT_SET_EXT_KEY_END))
+		end = (const u8 *)nft_set_ext_key_end(ext)->data;
+	else
+		end = start;
+
 	dup = pipapo_get(net, set, start, genmask);
-	if (PTR_ERR(dup) == -ENOENT) {
-		if (nft_set_ext_exists(ext, NFT_SET_EXT_KEY_END)) {
-			end = (const u8 *)nft_set_ext_key_end(ext)->data;
-			dup = pipapo_get(net, set, end, nft_genmask_next(net));
-		} else {
-			end = start;
+	if (!IS_ERR(dup)) {
+		/* Check if we already have the same exact entry */
+		const struct nft_data *dup_key, *dup_end;
+
+		dup_key = nft_set_ext_key(&dup->ext);
+		if (nft_set_ext_exists(&dup->ext, NFT_SET_EXT_KEY_END))
+			dup_end = nft_set_ext_key_end(&dup->ext);
+		else
+			dup_end = dup_key;
+
+		if (!memcmp(start, dup_key->data, sizeof(*dup_key->data)) &&
+		    !memcmp(end, dup_end->data, sizeof(*dup_end->data))) {
+			*ext2 = &dup->ext;
+			return -EEXIST;
 		}
+
+		return -ENOTEMPTY;
+	}
+
+	if (PTR_ERR(dup) == -ENOENT) {
+		/* Look for partially overlapping entries */
+		dup = pipapo_get(net, set, end, nft_genmask_next(net));
 	}
 
 	if (PTR_ERR(dup) != -ENOENT) {
 		if (IS_ERR(dup))
 			return PTR_ERR(dup);
 		*ext2 = &dup->ext;
-		return -EEXIST;
+		return -ENOTEMPTY;
 	}
 
 	/* Validate */
diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c
index 5000b93..8617fc1 100644
--- a/net/netfilter/nft_set_rbtree.c
+++ b/net/netfilter/nft_set_rbtree.c
@@ -33,6 +33,11 @@
 	       (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END);
 }
 
+static bool nft_rbtree_interval_start(const struct nft_rbtree_elem *rbe)
+{
+	return !nft_rbtree_interval_end(rbe);
+}
+
 static bool nft_rbtree_equal(const struct nft_set *set, const void *this,
 			     const struct nft_rbtree_elem *interval)
 {
@@ -64,7 +69,7 @@
 			if (interval &&
 			    nft_rbtree_equal(set, this, interval) &&
 			    nft_rbtree_interval_end(rbe) &&
-			    !nft_rbtree_interval_end(interval))
+			    nft_rbtree_interval_start(interval))
 				continue;
 			interval = rbe;
 		} else if (d > 0)
@@ -89,7 +94,7 @@
 
 	if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
 	    nft_set_elem_active(&interval->ext, genmask) &&
-	    !nft_rbtree_interval_end(interval)) {
+	    nft_rbtree_interval_start(interval)) {
 		*ext = &interval->ext;
 		return true;
 	}
@@ -208,8 +213,43 @@
 	u8 genmask = nft_genmask_next(net);
 	struct nft_rbtree_elem *rbe;
 	struct rb_node *parent, **p;
+	bool overlap = false;
 	int d;
 
+	/* Detect overlaps as we descend the tree. Set the flag in these cases:
+	 *
+	 * a1. |__ _ _?  >|__ _ _  (insert start after existing start)
+	 * a2. _ _ __>|  ?_ _ __|  (insert end before existing end)
+	 * a3. _ _ ___|  ?_ _ _>|  (insert end after existing end)
+	 * a4. >|__ _ _   _ _ __|  (insert start before existing end)
+	 *
+	 * and clear it later on, as we eventually reach the points indicated by
+	 * '?' above, in the cases described below. We'll always meet these
+	 * later, locally, due to tree ordering, and overlaps for the intervals
+	 * that are the closest together are always evaluated last.
+	 *
+	 * b1. |__ _ _!  >|__ _ _  (insert start after existing end)
+	 * b2. _ _ __>|  !_ _ __|  (insert end before existing start)
+	 * b3. !_____>|            (insert end after existing start)
+	 *
+	 * Case a4. resolves to b1.:
+	 * - if the inserted start element is the leftmost, because the '0'
+	 *   element in the tree serves as end element
+	 * - otherwise, if an existing end is found. Note that end elements are
+	 *   always inserted after corresponding start elements.
+	 *
+	 * For a new, rightmost pair of elements, we'll hit cases b1. and b3.,
+	 * in that order.
+	 *
+	 * The flag is also cleared in two special cases:
+	 *
+	 * b4. |__ _ _!|<_ _ _   (insert start right before existing end)
+	 * b5. |__ _ >|!__ _ _   (insert end right after existing start)
+	 *
+	 * which always happen as last step and imply that no further
+	 * overlapping is possible.
+	 */
+
 	parent = NULL;
 	p = &priv->root.rb_node;
 	while (*p != NULL) {
@@ -218,17 +258,42 @@
 		d = memcmp(nft_set_ext_key(&rbe->ext),
 			   nft_set_ext_key(&new->ext),
 			   set->klen);
-		if (d < 0)
+		if (d < 0) {
 			p = &parent->rb_left;
-		else if (d > 0)
+
+			if (nft_rbtree_interval_start(new)) {
+				overlap = nft_rbtree_interval_start(rbe) &&
+					  nft_set_elem_active(&rbe->ext,
+							      genmask);
+			} else {
+				overlap = nft_rbtree_interval_end(rbe) &&
+					  nft_set_elem_active(&rbe->ext,
+							      genmask);
+			}
+		} else if (d > 0) {
 			p = &parent->rb_right;
-		else {
+
+			if (nft_rbtree_interval_end(new)) {
+				overlap = nft_rbtree_interval_end(rbe) &&
+					  nft_set_elem_active(&rbe->ext,
+							      genmask);
+			} else if (nft_rbtree_interval_end(rbe) &&
+				   nft_set_elem_active(&rbe->ext, genmask)) {
+				overlap = true;
+			}
+		} else {
 			if (nft_rbtree_interval_end(rbe) &&
-			    !nft_rbtree_interval_end(new)) {
+			    nft_rbtree_interval_start(new)) {
 				p = &parent->rb_left;
-			} else if (!nft_rbtree_interval_end(rbe) &&
+
+				if (nft_set_elem_active(&rbe->ext, genmask))
+					overlap = false;
+			} else if (nft_rbtree_interval_start(rbe) &&
 				   nft_rbtree_interval_end(new)) {
 				p = &parent->rb_right;
+
+				if (nft_set_elem_active(&rbe->ext, genmask))
+					overlap = false;
 			} else if (nft_set_elem_active(&rbe->ext, genmask)) {
 				*ext = &rbe->ext;
 				return -EEXIST;
@@ -237,6 +302,10 @@
 			}
 		}
 	}
+
+	if (overlap)
+		return -ENOTEMPTY;
+
 	rb_link_node_rcu(&new->node, parent, p);
 	rb_insert_color(&new->node, &priv->root);
 	return 0;
@@ -317,10 +386,10 @@
 			parent = parent->rb_right;
 		else {
 			if (nft_rbtree_interval_end(rbe) &&
-			    !nft_rbtree_interval_end(this)) {
+			    nft_rbtree_interval_start(this)) {
 				parent = parent->rb_left;
 				continue;
-			} else if (!nft_rbtree_interval_end(rbe) &&
+			} else if (nft_rbtree_interval_start(rbe) &&
 				   nft_rbtree_interval_end(this)) {
 				parent = parent->rb_right;
 				continue;
diff --git a/tools/testing/selftests/netfilter/Makefile b/tools/testing/selftests/netfilter/Makefile
index 08194aa..9c0f758 100644
--- a/tools/testing/selftests/netfilter/Makefile
+++ b/tools/testing/selftests/netfilter/Makefile
@@ -3,6 +3,10 @@
 
 TEST_PROGS := nft_trans_stress.sh nft_nat.sh bridge_brouter.sh \
 	conntrack_icmp_related.sh nft_flowtable.sh ipvs.sh \
-	nft_concat_range.sh
+	nft_concat_range.sh \
+	nft_queue.sh
+
+LDLIBS = -lmnl
+TEST_GEN_FILES =  nf-queue
 
 include ../lib.mk
diff --git a/tools/testing/selftests/netfilter/config b/tools/testing/selftests/netfilter/config
index 59caa8f..4faf2ce 100644
--- a/tools/testing/selftests/netfilter/config
+++ b/tools/testing/selftests/netfilter/config
@@ -1,2 +1,8 @@
 CONFIG_NET_NS=y
 CONFIG_NF_TABLES_INET=y
+CONFIG_NFT_QUEUE=m
+CONFIG_NFT_NAT=m
+CONFIG_NFT_REDIR=m
+CONFIG_NFT_MASQ=m
+CONFIG_NFT_FLOW_OFFLOAD=m
+CONFIG_NF_CT_NETLINK=m
diff --git a/tools/testing/selftests/netfilter/nf-queue.c b/tools/testing/selftests/netfilter/nf-queue.c
new file mode 100644
index 0000000..29c73bc
--- /dev/null
+++ b/tools/testing/selftests/netfilter/nf-queue.c
@@ -0,0 +1,352 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <time.h>
+#include <arpa/inet.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_queue.h>
+
+struct options {
+	bool count_packets;
+	int verbose;
+	unsigned int queue_num;
+	unsigned int timeout;
+};
+
+static unsigned int queue_stats[5];
+static struct options opts;
+
+static void help(const char *p)
+{
+	printf("Usage: %s [-c|-v [-vv] ] [-t timeout] [-q queue_num]\n", p);
+}
+
+static int parse_attr_cb(const struct nlattr *attr, void *data)
+{
+	const struct nlattr **tb = data;
+	int type = mnl_attr_get_type(attr);
+
+	/* skip unsupported attribute in user-space */
+	if (mnl_attr_type_valid(attr, NFQA_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch (type) {
+	case NFQA_MARK:
+	case NFQA_IFINDEX_INDEV:
+	case NFQA_IFINDEX_OUTDEV:
+	case NFQA_IFINDEX_PHYSINDEV:
+	case NFQA_IFINDEX_PHYSOUTDEV:
+		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFQA_TIMESTAMP:
+		if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
+		    sizeof(struct nfqnl_msg_packet_timestamp)) < 0) {
+			perror("mnl_attr_validate2");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFQA_HWADDR:
+		if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
+		    sizeof(struct nfqnl_msg_packet_hw)) < 0) {
+			perror("mnl_attr_validate2");
+			return MNL_CB_ERROR;
+		}
+		break;
+	case NFQA_PAYLOAD:
+		break;
+	}
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static int queue_cb(const struct nlmsghdr *nlh, void *data)
+{
+	struct nlattr *tb[NFQA_MAX+1] = { 0 };
+	struct nfqnl_msg_packet_hdr *ph = NULL;
+	uint32_t id = 0;
+
+	(void)data;
+
+	mnl_attr_parse(nlh, sizeof(struct nfgenmsg), parse_attr_cb, tb);
+	if (tb[NFQA_PACKET_HDR]) {
+		ph = mnl_attr_get_payload(tb[NFQA_PACKET_HDR]);
+		id = ntohl(ph->packet_id);
+
+		if (opts.verbose > 0)
+			printf("packet hook=%u, hwproto 0x%x",
+				ntohs(ph->hw_protocol), ph->hook);
+
+		if (ph->hook >= 5) {
+			fprintf(stderr, "Unknown hook %d\n", ph->hook);
+			return MNL_CB_ERROR;
+		}
+
+		if (opts.verbose > 0) {
+			uint32_t skbinfo = 0;
+
+			if (tb[NFQA_SKB_INFO])
+				skbinfo = ntohl(mnl_attr_get_u32(tb[NFQA_SKB_INFO]));
+			if (skbinfo & NFQA_SKB_CSUMNOTREADY)
+				printf(" csumnotready");
+			if (skbinfo & NFQA_SKB_GSO)
+				printf(" gso");
+			if (skbinfo & NFQA_SKB_CSUM_NOTVERIFIED)
+				printf(" csumnotverified");
+			puts("");
+		}
+
+		if (opts.count_packets)
+			queue_stats[ph->hook]++;
+	}
+
+	return MNL_CB_OK + id;
+}
+
+static struct nlmsghdr *
+nfq_build_cfg_request(char *buf, uint8_t command, int queue_num)
+{
+	struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
+	struct nfqnl_msg_config_cmd cmd = {
+		.command = command,
+		.pf = htons(AF_INET),
+	};
+	struct nfgenmsg *nfg;
+
+	nlh->nlmsg_type	= (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG;
+	nlh->nlmsg_flags = NLM_F_REQUEST;
+
+	nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
+
+	nfg->nfgen_family = AF_UNSPEC;
+	nfg->version = NFNETLINK_V0;
+	nfg->res_id = htons(queue_num);
+
+	mnl_attr_put(nlh, NFQA_CFG_CMD, sizeof(cmd), &cmd);
+
+	return nlh;
+}
+
+static struct nlmsghdr *
+nfq_build_cfg_params(char *buf, uint8_t mode, int range, int queue_num)
+{
+	struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
+	struct nfqnl_msg_config_params params = {
+		.copy_range = htonl(range),
+		.copy_mode = mode,
+	};
+	struct nfgenmsg *nfg;
+
+	nlh->nlmsg_type	= (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG;
+	nlh->nlmsg_flags = NLM_F_REQUEST;
+
+	nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
+	nfg->nfgen_family = AF_UNSPEC;
+	nfg->version = NFNETLINK_V0;
+	nfg->res_id = htons(queue_num);
+
+	mnl_attr_put(nlh, NFQA_CFG_PARAMS, sizeof(params), &params);
+
+	return nlh;
+}
+
+static struct nlmsghdr *
+nfq_build_verdict(char *buf, int id, int queue_num, int verd)
+{
+	struct nfqnl_msg_verdict_hdr vh = {
+		.verdict = htonl(verd),
+		.id = htonl(id),
+	};
+	struct nlmsghdr *nlh;
+	struct nfgenmsg *nfg;
+
+	nlh = mnl_nlmsg_put_header(buf);
+	nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_VERDICT;
+	nlh->nlmsg_flags = NLM_F_REQUEST;
+	nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
+	nfg->nfgen_family = AF_UNSPEC;
+	nfg->version = NFNETLINK_V0;
+	nfg->res_id = htons(queue_num);
+
+	mnl_attr_put(nlh, NFQA_VERDICT_HDR, sizeof(vh), &vh);
+
+	return nlh;
+}
+
+static void print_stats(void)
+{
+	unsigned int last, total;
+	int i;
+
+	if (!opts.count_packets)
+		return;
+
+	total = 0;
+	last = queue_stats[0];
+
+	for (i = 0; i < 5; i++) {
+		printf("hook %d packets %08u\n", i, queue_stats[i]);
+		last = queue_stats[i];
+		total += last;
+	}
+
+	printf("%u packets total\n", total);
+}
+
+struct mnl_socket *open_queue(void)
+{
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+	unsigned int queue_num;
+	struct mnl_socket *nl;
+	struct nlmsghdr *nlh;
+	struct timeval tv;
+	uint32_t flags;
+
+	nl = mnl_socket_open(NETLINK_NETFILTER);
+	if (nl == NULL) {
+		perror("mnl_socket_open");
+		exit(EXIT_FAILURE);
+	}
+
+	if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
+		perror("mnl_socket_bind");
+		exit(EXIT_FAILURE);
+	}
+
+	queue_num = opts.queue_num;
+	nlh = nfq_build_cfg_request(buf, NFQNL_CFG_CMD_BIND, queue_num);
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_sendto");
+		exit(EXIT_FAILURE);
+	}
+
+	nlh = nfq_build_cfg_params(buf, NFQNL_COPY_PACKET, 0xFFFF, queue_num);
+
+	flags = NFQA_CFG_F_GSO | NFQA_CFG_F_UID_GID;
+	mnl_attr_put_u32(nlh, NFQA_CFG_FLAGS, htonl(flags));
+	mnl_attr_put_u32(nlh, NFQA_CFG_MASK, htonl(flags));
+
+	if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+		perror("mnl_socket_sendto");
+		exit(EXIT_FAILURE);
+	}
+
+	memset(&tv, 0, sizeof(tv));
+	tv.tv_sec = opts.timeout;
+	if (opts.timeout && setsockopt(mnl_socket_get_fd(nl),
+				       SOL_SOCKET, SO_RCVTIMEO,
+				       &tv, sizeof(tv))) {
+		perror("setsockopt(SO_RCVTIMEO)");
+		exit(EXIT_FAILURE);
+	}
+
+	return nl;
+}
+
+static int mainloop(void)
+{
+	unsigned int buflen = 64 * 1024 + MNL_SOCKET_BUFFER_SIZE;
+	struct mnl_socket *nl;
+	struct nlmsghdr *nlh;
+	unsigned int portid;
+	char *buf;
+	int ret;
+
+	buf = malloc(buflen);
+	if (!buf) {
+		perror("malloc");
+		exit(EXIT_FAILURE);
+	}
+
+	nl = open_queue();
+	portid = mnl_socket_get_portid(nl);
+
+	for (;;) {
+		uint32_t id;
+
+		ret = mnl_socket_recvfrom(nl, buf, buflen);
+		if (ret == -1) {
+			if (errno == ENOBUFS)
+				continue;
+
+			if (errno == EAGAIN) {
+				errno = 0;
+				ret = 0;
+				break;
+			}
+
+			perror("mnl_socket_recvfrom");
+			exit(EXIT_FAILURE);
+		}
+
+		ret = mnl_cb_run(buf, ret, 0, portid, queue_cb, NULL);
+		if (ret < 0) {
+			perror("mnl_cb_run");
+			exit(EXIT_FAILURE);
+		}
+
+		id = ret - MNL_CB_OK;
+		nlh = nfq_build_verdict(buf, id, opts.queue_num, NF_ACCEPT);
+		if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
+			perror("mnl_socket_sendto");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	mnl_socket_close(nl);
+
+	return ret;
+}
+
+static void parse_opts(int argc, char **argv)
+{
+	int c;
+
+	while ((c = getopt(argc, argv, "chvt:q:")) != -1) {
+		switch (c) {
+		case 'c':
+			opts.count_packets = true;
+			break;
+		case 'h':
+			help(argv[0]);
+			exit(0);
+			break;
+		case 'q':
+			opts.queue_num = atoi(optarg);
+			if (opts.queue_num > 0xffff)
+				opts.queue_num = 0;
+			break;
+		case 't':
+			opts.timeout = atoi(optarg);
+			break;
+		case 'v':
+			opts.verbose++;
+			break;
+		}
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	int ret;
+
+	parse_opts(argc, argv);
+
+	ret = mainloop();
+	if (opts.count_packets)
+		print_stats();
+
+	return ret;
+}
diff --git a/tools/testing/selftests/netfilter/nft_queue.sh b/tools/testing/selftests/netfilter/nft_queue.sh
new file mode 100755
index 0000000..6898448
--- /dev/null
+++ b/tools/testing/selftests/netfilter/nft_queue.sh
@@ -0,0 +1,332 @@
+#!/bin/bash
+#
+# This tests nf_queue:
+# 1. can process packets from all hooks
+# 2. support running nfqueue from more than one base chain
+#
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+ret=0
+
+sfx=$(mktemp -u "XXXXXXXX")
+ns1="ns1-$sfx"
+ns2="ns2-$sfx"
+nsrouter="nsrouter-$sfx"
+
+cleanup()
+{
+	ip netns del ${ns1}
+	ip netns del ${ns2}
+	ip netns del ${nsrouter}
+	rm -f "$TMPFILE0"
+	rm -f "$TMPFILE1"
+}
+
+nft --version > /dev/null 2>&1
+if [ $? -ne 0 ];then
+	echo "SKIP: Could not run test without nft tool"
+	exit $ksft_skip
+fi
+
+ip -Version > /dev/null 2>&1
+if [ $? -ne 0 ];then
+	echo "SKIP: Could not run test without ip tool"
+	exit $ksft_skip
+fi
+
+ip netns add ${nsrouter}
+if [ $? -ne 0 ];then
+	echo "SKIP: Could not create net namespace"
+	exit $ksft_skip
+fi
+
+TMPFILE0=$(mktemp)
+TMPFILE1=$(mktemp)
+trap cleanup EXIT
+
+ip netns add ${ns1}
+ip netns add ${ns2}
+
+ip link add veth0 netns ${nsrouter} type veth peer name eth0 netns ${ns1} > /dev/null 2>&1
+if [ $? -ne 0 ];then
+    echo "SKIP: No virtual ethernet pair device support in kernel"
+    exit $ksft_skip
+fi
+ip link add veth1 netns ${nsrouter} type veth peer name eth0 netns ${ns2}
+
+ip -net ${nsrouter} link set lo up
+ip -net ${nsrouter} link set veth0 up
+ip -net ${nsrouter} addr add 10.0.1.1/24 dev veth0
+ip -net ${nsrouter} addr add dead:1::1/64 dev veth0
+
+ip -net ${nsrouter} link set veth1 up
+ip -net ${nsrouter} addr add 10.0.2.1/24 dev veth1
+ip -net ${nsrouter} addr add dead:2::1/64 dev veth1
+
+ip -net ${ns1} link set lo up
+ip -net ${ns1} link set eth0 up
+
+ip -net ${ns2} link set lo up
+ip -net ${ns2} link set eth0 up
+
+ip -net ${ns1} addr add 10.0.1.99/24 dev eth0
+ip -net ${ns1} addr add dead:1::99/64 dev eth0
+ip -net ${ns1} route add default via 10.0.1.1
+ip -net ${ns1} route add default via dead:1::1
+
+ip -net ${ns2} addr add 10.0.2.99/24 dev eth0
+ip -net ${ns2} addr add dead:2::99/64 dev eth0
+ip -net ${ns2} route add default via 10.0.2.1
+ip -net ${ns2} route add default via dead:2::1
+
+load_ruleset() {
+	local name=$1
+	local prio=$2
+
+ip netns exec ${nsrouter} nft -f - <<EOF
+table inet $name {
+	chain nfq {
+		ip protocol icmp queue bypass
+		icmpv6 type { "echo-request", "echo-reply" } queue num 1 bypass
+	}
+	chain pre {
+		type filter hook prerouting priority $prio; policy accept;
+		jump nfq
+	}
+	chain input {
+		type filter hook input priority $prio; policy accept;
+		jump nfq
+	}
+	chain forward {
+		type filter hook forward priority $prio; policy accept;
+		tcp dport 12345 queue num 2
+		jump nfq
+	}
+	chain output {
+		type filter hook output priority $prio; policy accept;
+		tcp dport 12345 queue num 3
+		jump nfq
+	}
+	chain post {
+		type filter hook postrouting priority $prio; policy accept;
+		jump nfq
+	}
+}
+EOF
+}
+
+load_counter_ruleset() {
+	local prio=$1
+
+ip netns exec ${nsrouter} nft -f - <<EOF
+table inet countrules {
+	chain pre {
+		type filter hook prerouting priority $prio; policy accept;
+		counter
+	}
+	chain input {
+		type filter hook input priority $prio; policy accept;
+		counter
+	}
+	chain forward {
+		type filter hook forward priority $prio; policy accept;
+		counter
+	}
+	chain output {
+		type filter hook output priority $prio; policy accept;
+		counter
+	}
+	chain post {
+		type filter hook postrouting priority $prio; policy accept;
+		counter
+	}
+}
+EOF
+}
+
+test_ping() {
+  ip netns exec ${ns1} ping -c 1 -q 10.0.2.99 > /dev/null
+  if [ $? -ne 0 ];then
+	return 1
+  fi
+
+  ip netns exec ${ns1} ping -c 1 -q dead:2::99 > /dev/null
+  if [ $? -ne 0 ];then
+	return 1
+  fi
+
+  return 0
+}
+
+test_ping_router() {
+  ip netns exec ${ns1} ping -c 1 -q 10.0.2.1 > /dev/null
+  if [ $? -ne 0 ];then
+	return 1
+  fi
+
+  ip netns exec ${ns1} ping -c 1 -q dead:2::1 > /dev/null
+  if [ $? -ne 0 ];then
+	return 1
+  fi
+
+  return 0
+}
+
+test_queue_blackhole() {
+	local proto=$1
+
+ip netns exec ${nsrouter} nft -f - <<EOF
+table $proto blackh {
+	chain forward {
+	type filter hook forward priority 0; policy accept;
+		queue num 600
+	}
+}
+EOF
+	if [ $proto = "ip" ] ;then
+		ip netns exec ${ns1} ping -c 1 -q 10.0.2.99 > /dev/null
+		lret=$?
+	elif [ $proto = "ip6" ]; then
+		ip netns exec ${ns1} ping -c 1 -q dead:2::99 > /dev/null
+		lret=$?
+	else
+		lret=111
+	fi
+
+	# queue without bypass keyword should drop traffic if no listener exists.
+	if [ $lret -eq 0 ];then
+		echo "FAIL: $proto expected failure, got $lret" 1>&2
+		exit 1
+	fi
+
+	ip netns exec ${nsrouter} nft delete table $proto blackh
+	if [ $? -ne 0 ] ;then
+	        echo "FAIL: $proto: Could not delete blackh table"
+	        exit 1
+	fi
+
+        echo "PASS: $proto: statement with no listener results in packet drop"
+}
+
+test_queue()
+{
+	local expected=$1
+	local last=""
+
+	# spawn nf-queue listeners
+	ip netns exec ${nsrouter} ./nf-queue -c -q 0 -t 3 > "$TMPFILE0" &
+	ip netns exec ${nsrouter} ./nf-queue -c -q 1 -t 3 > "$TMPFILE1" &
+	sleep 1
+	test_ping
+	ret=$?
+	if [ $ret -ne 0 ];then
+		echo "FAIL: netns routing/connectivity with active listener on queue $queue: $ret" 1>&2
+		exit $ret
+	fi
+
+	test_ping_router
+	ret=$?
+	if [ $ret -ne 0 ];then
+		echo "FAIL: netns router unreachable listener on queue $queue: $ret" 1>&2
+		exit $ret
+	fi
+
+	wait
+	ret=$?
+
+	for file in $TMPFILE0 $TMPFILE1; do
+		last=$(tail -n1 "$file")
+		if [ x"$last" != x"$expected packets total" ]; then
+			echo "FAIL: Expected $expected packets total, but got $last" 1>&2
+			cat "$file" 1>&2
+
+			ip netns exec ${nsrouter} nft list ruleset
+			exit 1
+		fi
+	done
+
+	echo "PASS: Expected and received $last"
+}
+
+test_tcp_forward()
+{
+	ip netns exec ${nsrouter} ./nf-queue -q 2 -t 10 &
+	local nfqpid=$!
+
+	tmpfile=$(mktemp) || exit 1
+	dd conv=sparse status=none if=/dev/zero bs=1M count=100 of=$tmpfile
+	ip netns exec ${ns2} nc -w 5 -l -p 12345 <"$tmpfile" >/dev/null &
+	local rpid=$!
+
+	sleep 1
+	ip netns exec ${ns1} nc -w 5 10.0.2.99 12345 <"$tmpfile" >/dev/null &
+
+	rm -f "$tmpfile"
+
+	wait $rpid
+	wait $lpid
+	[ $? -eq 0 ] && echo "PASS: tcp and nfqueue in forward chain"
+}
+
+test_tcp_localhost()
+{
+	tc -net "${nsrouter}" qdisc add dev lo root netem loss random 1%
+
+	tmpfile=$(mktemp) || exit 1
+
+	dd conv=sparse status=none if=/dev/zero bs=1M count=900 of=$tmpfile
+	ip netns exec ${nsrouter} nc -w 5 -l -p 12345 <"$tmpfile" >/dev/null &
+	local rpid=$!
+
+	ip netns exec ${nsrouter} ./nf-queue -q 3 -t 30 &
+	local nfqpid=$!
+
+	sleep 1
+	ip netns exec ${nsrouter} nc -w 5 127.0.0.1 12345 <"$tmpfile" > /dev/null
+	rm -f "$tmpfile"
+
+	wait $rpid
+	[ $? -eq 0 ] && echo "PASS: tcp via loopback"
+}
+
+ip netns exec ${nsrouter} sysctl net.ipv6.conf.all.forwarding=1 > /dev/null
+ip netns exec ${nsrouter} sysctl net.ipv4.conf.veth0.forwarding=1 > /dev/null
+ip netns exec ${nsrouter} sysctl net.ipv4.conf.veth1.forwarding=1 > /dev/null
+
+load_ruleset "filter" 0
+
+sleep 3
+
+test_ping
+ret=$?
+if [ $ret -eq 0 ];then
+	# queue bypass works (rules were skipped, no listener)
+	echo "PASS: ${ns1} can reach ${ns2}"
+else
+	echo "FAIL: ${ns1} cannot reach ${ns2}: $ret" 1>&2
+	exit $ret
+fi
+
+test_queue_blackhole ip
+test_queue_blackhole ip6
+
+# dummy ruleset to add base chains between the
+# queueing rules.  We don't want the second reinject
+# to re-execute the old hooks.
+load_counter_ruleset 10
+
+# we are hooking all: prerouting/input/forward/output/postrouting.
+# we ping ${ns2} from ${ns1} via ${nsrouter} using ipv4 and ipv6, so:
+# 1x icmp prerouting,forward,postrouting -> 3 queue events (6 incl. reply).
+# 1x icmp prerouting,input,output postrouting -> 4 queue events incl. reply.
+# so we expect that userspace program receives 10 packets.
+test_queue 10
+
+# same.  We queue to a second program as well.
+load_ruleset "filter2" 20
+test_queue 20
+
+test_tcp_forward
+test_tcp_localhost
+
+exit $ret