netlink: improve interface handling

* Separate interface creation from interface modification code
* Support setting some interface attributes (ifdescr, mtu, up/down, promisc)
* Improve interaction with the cloners requiring to parse/write custom
 interface attributes
* Add bitmask-based way of checking if the attribute is present in the
message
* Don't use multipart RTM_GETLINK replies when searching for the
specific interface names
* Use ENODEV instead of ENOENT in case of failed RTM_GETLINK search
* Add python netlink test helpers
* Add some netlink interface tests

Differential Revision: https://reviews.freebsd.org/D37668

(cherry picked from commit 80f03e63d67ede8fedbed4bd6bf6b12ec2ab2cfb)

12 files changed, 2116 insertions, 53 deletions

diff --git a/etc/mtree/BSD.tests.dist b/etc/mtree/BSD.tests.dist
index 475b9571d8e9..0dabe96110d8 100644
--- a/etc/mtree/BSD.tests.dist
+++ b/etc/mtree/BSD.tests.dist
@@ -820,6 +820,8 @@
             tunnel
             ..
         ..
+        netlink
+        ..
         netmap
         ..
         netpfil
diff --git a/share/man/man4/rtnetlink.4 b/share/man/man4/rtnetlink.4
index 9f20671719f0..a06807809691 100644
--- a/share/man/man4/rtnetlink.4
+++ b/share/man/man4/rtnetlink.4
@@ -309,6 +309,8 @@ IFLA_ALT_IFNAME	interface name
 (binary) (readonly) Link-level broadcast address.
 .It Dv IFLA_IFNAME
 (string) New interface name.
+.It Dv IFLA_IFALIAS
+(string) Interface description.
 .It Dv IFLA_LINK
 (uint32_t) (readonly) Interface index.
 .It Dv IFLA_MASTER
diff --git a/sys/netlink/netlink_message_parser.c b/sys/netlink/netlink_message_parser.c
index d33eddb800e4..451d9d497491 100644
--- a/sys/netlink/netlink_message_parser.c
+++ b/sys/netlink/netlink_message_parser.c
@@ -147,17 +147,23 @@ nl_parse_attrs_raw(struct nlattr *nla_head, int len, const struct nlattr_parser
 	return (0);
 }
 
-int
-nl_parse_attrs(struct nlmsghdr *hdr, int hdrlen, struct nlattr_parser *ps, int pslen,
-    struct nl_pstate *npt, void *target)
+void
+nl_get_attrs_bmask_raw(struct nlattr *nla_head, int len, struct nlattr_bmask *bm)
 {
-	int off = NLMSG_HDRLEN + NETLINK_ALIGN(hdrlen);
-	int len = hdr->nlmsg_len - off;
-	struct nlattr *nla_head = (struct nlattr *)((char *)hdr + off);
+	struct nlattr *nla = NULL;
+
+	bzero(bm->mask, sizeof(bm->mask));
 
-	return (nl_parse_attrs_raw(nla_head, len, ps, pslen, npt, target));
+	NLA_FOREACH(nla, nla_head, len) {
+		if (nla->nla_len < sizeof(struct nlattr))
+			return;
+		int nla_type = nla->nla_type & NLA_TYPE_MASK;
+		if (nla_type <= sizeof(bm->mask) * 8)
+			bm->mask[nla_type / 8] |= 1 << (nla_type % 8);
+	}
 }
 
+
 int
 nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
 {
diff --git a/sys/netlink/netlink_message_parser.h b/sys/netlink/netlink_message_parser.h
index b23b223ef80e..96fd1c7337b7 100644
--- a/sys/netlink/netlink_message_parser.h
+++ b/sys/netlink/netlink_message_parser.h
@@ -152,15 +152,21 @@ static const struct nlhdr_parser _name = {		\
 	.np_size = NL_ARRAY_LEN(_np),			\
 }
 
-struct nlarr_hdr {
-	int num_items;
-	int max_items;
+struct nlattr_bmask {
+	uint64_t			mask[2];
 };
 
+static inline bool
+nl_has_attr(const struct nlattr_bmask *bm, unsigned int attr_type)
+{
+	MPASS(attr_type < sizeof(bm->mask) * 8);
+
+	return ((bm->mask[attr_type / 8] & (1 << (attr_type % 8))));
+}
+void nl_get_attrs_bmask_raw(struct nlattr *nla_head, int len, struct nlattr_bmask *bm);
+
 int nl_parse_attrs_raw(struct nlattr *nla_head, int len, const struct nlattr_parser *ps,
     int pslen, struct nl_pstate *npt, void *target);
-int nl_parse_attrs(struct nlmsghdr *hdr, int hdrlen, struct nlattr_parser *ps,
-    int pslen, struct nl_pstate *npt, void *target);
 
 int nlattr_get_flag(struct nlattr *nla, struct nl_pstate *npt,
     const void *arg, void *target);
@@ -270,5 +276,17 @@ nl_parse_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser,
 	return (nl_parse_header(hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser, npt, target));
 }
 
+static inline void
+nl_get_attrs_bmask_nlmsg(struct nlmsghdr *hdr, const struct nlhdr_parser *parser,
+    struct nlattr_bmask *bm)
+{
+	struct nlattr *nla_head;
+
+	nla_head = (struct nlattr *)((char *)(hdr + 1) + parser->nl_hdr_off);
+	int len = hdr->nlmsg_len - sizeof(*hdr) - parser->nl_hdr_off;
+
+	nl_get_attrs_bmask_raw(nla_head, len, bm);
+}
+
 #endif
 #endif
diff --git a/sys/netlink/route/iface.c b/sys/netlink/route/iface.c
index 579869e9662c..b033ba71009d 100644
--- a/sys/netlink/route/iface.c
+++ b/sys/netlink/route/iface.c
@@ -75,6 +75,8 @@ static SLIST_HEAD(, nl_cloner) nl_cloners = SLIST_HEAD_INITIALIZER(nl_cloners);
 static struct sx rtnl_cloner_lock;
 SX_SYSINIT(rtnl_cloner_lock, &rtnl_cloner_lock, "rtnl cloner lock");
 
+static struct nl_cloner *rtnl_iface_find_cloner_locked(const char *name);
+
 /*
  * RTM_GETLINK request
  * sendto(3, {{len=32, type=RTM_GETLINK, flags=NLM_F_REQUEST|NLM_F_DUMP, seq=1641940952, pid=0},
@@ -286,11 +288,23 @@ dump_iface(struct nl_writer *nw, struct ifnet *ifp, const struct nlmsghdr *hdr,
         nlattr_add_u32(nw, IFLA_MAX_MTU, 9000);
         nlattr_add_u32(nw, IFLA_GROUP, 0);
 */
+
+	if (ifp->if_description != NULL)
+		nlattr_add_string(nw, IFLA_IFALIAS, ifp->if_description);
+
 	get_stats(nw, ifp);
 
 	uint32_t val = (ifp->if_flags & IFF_PROMISC) != 0;
         nlattr_add_u32(nw, IFLA_PROMISCUITY, val);
 
+	sx_slock(&rtnl_cloner_lock);
+	struct nl_cloner *cloner = rtnl_iface_find_cloner_locked(ifp->if_dname);
+	if (cloner != NULL && cloner->dump_f != NULL) {
+		/* Ignore any dump error */
+		cloner->dump_f(ifp, nw);
+	}
+	sx_sunlock(&rtnl_cloner_lock);
+
         if (nlmsg_end(nw))
 		return (true);
 
@@ -320,6 +334,8 @@ check_ifmsg(void *hdr, struct nl_pstate *npt)
 static const struct nlfield_parser nlf_p_if[] = {
 	{ .off_in = _IN(ifi_type), .off_out = _OUT(ifi_type), .cb = nlf_get_u16 },
 	{ .off_in = _IN(ifi_index), .off_out = _OUT(ifi_index), .cb = nlf_get_u32 },
+	{ .off_in = _IN(ifi_flags), .off_out = _OUT(ifi_flags), .cb = nlf_get_u32 },
+	{ .off_in = _IN(ifi_change), .off_out = _OUT(ifi_change), .cb = nlf_get_u32 },
 };
 
 static const struct nlattr_parser nla_p_linfo[] = {
@@ -333,6 +349,7 @@ static const struct nlattr_parser nla_p_if[] = {
 	{ .type = IFLA_MTU, .off = _OUT(ifla_mtu), .cb = nlattr_get_uint32 },
 	{ .type = IFLA_LINK, .off = _OUT(ifi_index), .cb = nlattr_get_uint32 },
 	{ .type = IFLA_LINKINFO, .arg = &linfo_parser, .cb = nlattr_get_nested },
+	{ .type = IFLA_IFALIAS, .off = _OUT(ifla_ifalias), .cb = nlattr_get_string },
 	{ .type = IFLA_GROUP, .off = _OUT(ifla_group), .cb = nlattr_get_string },
 	{ .type = IFLA_ALT_IFNAME, .off = _OUT(ifla_ifname), .cb = nlattr_get_string },
 };
@@ -379,28 +396,39 @@ rtnl_handle_getlink(struct nlmsghdr *hdr, struct nlpcb *nlp, struct nl_pstate *n
 		.nw = npt->nw,
 		.hdr.nlmsg_pid = hdr->nlmsg_pid,
 		.hdr.nlmsg_seq = hdr->nlmsg_seq,
-		.hdr.nlmsg_flags = hdr->nlmsg_flags | NLM_F_MULTI,
+		.hdr.nlmsg_flags = hdr->nlmsg_flags,
 		.hdr.nlmsg_type = NL_RTM_NEWLINK,
 	};
 
-	/* Fast track for an interface w/ explicit index match */
-	if (attrs.ifi_index != 0) {
-		NET_EPOCH_ENTER(et);
-		ifp = ifnet_byindex_ref(attrs.ifi_index);
-		NET_EPOCH_EXIT(et);
-		NLP_LOG(LOG_DEBUG3, nlp, "fast track -> searching index %u", attrs.ifi_index);
+	/* Fast track for an interface w/ explicit name or index match */
+	if ((attrs.ifi_index != 0) || (attrs.ifla_ifname != NULL)) {
+		if (attrs.ifi_index != 0) {
+			NLP_LOG(LOG_DEBUG3, nlp, "fast track -> searching index %u",
+			    attrs.ifi_index);
+			NET_EPOCH_ENTER(et);
+			ifp = ifnet_byindex_ref(attrs.ifi_index);
+			NET_EPOCH_EXIT(et);
+		} else {
+			NLP_LOG(LOG_DEBUG3, nlp, "fast track -> searching name %s",
+			    attrs.ifla_ifname);
+			ifp = ifunit_ref(attrs.ifla_ifname);
+		}
+
 		if (ifp != NULL) {
 			if (match_iface(&attrs, ifp)) {
 				if (!dump_iface(wa.nw, ifp, &wa.hdr, 0))
 					error = ENOMEM;
 			} else
-				error = ESRCH;
+				error = ENODEV;
 			if_rele(ifp);
 		} else
-			error = ESRCH;
+			error = ENODEV;
 		return (error);
 	}
 
+	/* Always treat non-direct-match as a multipart message */
+	wa.hdr.nlmsg_flags |= NLM_F_MULTI;
+
 	/*
 	 * Fetching some link properties require performing ioctl's that may be blocking.
 	 * Address it by saving referenced pointers of the matching links,
@@ -504,48 +532,146 @@ rtnl_handle_dellink(struct nlmsghdr *hdr, struct nlpcb *nlp, struct nl_pstate *n
 	return (error);
 }
 
+/*
+ * New link:
+ * type=RTM_NEWLINK, flags=NLM_F_REQUEST|NLM_F_ACK|NLM_F_EXCL|NLM_F_CREATE, seq=1668185590, pid=0},
+ *   {ifi_family=AF_UNSPEC, ifi_type=ARPHRD_NETROM, ifi_index=0, ifi_flags=0, ifi_change=0}
+ *    [
+ *     {{nla_len=8, nla_type=IFLA_MTU}, 123},
+ *     {{nla_len=10, nla_type=IFLA_IFNAME}, "vlan1"},
+ *     {{nla_len=24, nla_type=IFLA_LINKINFO},
+ *      [
+ *       {{nla_len=8, nla_type=IFLA_INFO_KIND}, "vlan"...},
+ *       {{nla_len=12, nla_type=IFLA_INFO_DATA}, "\x06\x00\x01\x00\x7b\x00\x00\x00"}]}]}
+ *
+ * Update link:
+ * type=RTM_NEWLINK, flags=NLM_F_REQUEST|NLM_F_ACK, seq=1668185923, pid=0},
+ * {ifi_family=AF_UNSPEC, ifi_type=ARPHRD_NETROM, ifi_index=if_nametoindex("lo"), ifi_flags=0, ifi_change=0},
+ * {{nla_len=8, nla_type=IFLA_MTU}, 123}}
+ *
+ *
+ * Check command availability:
+ * type=RTM_NEWLINK, flags=NLM_F_REQUEST|NLM_F_ACK, seq=0, pid=0},
+ *  {ifi_family=AF_UNSPEC, ifi_type=ARPHRD_NETROM, ifi_index=0, ifi_flags=0, ifi_change=0}
+ */
+
+
 static int
-rtnl_handle_newlink(struct nlmsghdr *hdr, struct nlpcb *nlp, struct nl_pstate *npt)
+create_link(struct nlmsghdr *hdr, struct nl_parsed_link *lattrs,
+    struct nlattr_bmask *bm, struct nlpcb *nlp, struct nl_pstate *npt)
 {
-	struct nl_cloner *cloner;
-	int error;
+	if (lattrs->ifla_ifname == NULL || strlen(lattrs->ifla_ifname) == 0) {
+		NLMSG_REPORT_ERR_MSG(npt, "empty IFLA_IFNAME attribute");
+		return (EINVAL);
+	}
+	if (lattrs->ifla_cloner == NULL || strlen(lattrs->ifla_cloner) == 0) {
+		NLMSG_REPORT_ERR_MSG(npt, "empty IFLA_INFO_KIND attribute");
+		return (EINVAL);
+	}
 
-	struct nl_parsed_link attrs = {};
-	error = nl_parse_nlmsg(hdr, &ifmsg_parser, npt, &attrs);
-	if (error != 0)
-		return (error);
+	bool found = false;
+	int error = 0;
+
+	sx_slock(&rtnl_cloner_lock);
+	struct nl_cloner *cloner = rtnl_iface_find_cloner_locked(lattrs->ifla_cloner);
+	if (cloner != NULL) {
+		found = true;
+		error = cloner->create_f(lattrs, bm, nlp, npt);
+	}
+	sx_sunlock(&rtnl_cloner_lock);
+
+	if (!found)
+		error = generic_cloner.create_f(lattrs, bm, nlp, npt);
+
+	return (error);
+}
+
+static int
+modify_link(struct nlmsghdr *hdr, struct nl_parsed_link *lattrs,
+    struct nlattr_bmask *bm, struct nlpcb *nlp, struct nl_pstate *npt)
+{
+	struct ifnet *ifp = NULL;
+	struct epoch_tracker et;
 
-	if (attrs.ifla_ifname == NULL || strlen(attrs.ifla_ifname) == 0) {
-		/* Applications like ip(8) verify RTM_NEWLINK existance
-		 * by calling it with empty arguments. Always return "innocent"
-		 * error.
+	if (lattrs->ifi_index == 0 && lattrs->ifla_ifname == NULL) {
+		/*
+		 * Applications like ip(8) verify RTM_NEWLINK command
+		 * existence by calling it with empty arguments. Always
+		 * return "innocent" error in that case.
 		 */
-		NLMSG_REPORT_ERR_MSG(npt, "empty IFLA_IFNAME attribute");
+		NLMSG_REPORT_ERR_MSG(npt, "empty ifi_index field");
 		return (EPERM);
 	}
 
-	if (attrs.ifla_cloner == NULL || strlen(attrs.ifla_cloner) == 0) {
-		NLMSG_REPORT_ERR_MSG(npt, "empty IFLA_INFO_KIND attribute");
-		return (EINVAL);
+	if (lattrs->ifi_index != 0) {
+		NET_EPOCH_ENTER(et);
+		ifp = ifnet_byindex_ref(lattrs->ifi_index);
+		NET_EPOCH_EXIT(et);
+		if (ifp == NULL) {
+			NLMSG_REPORT_ERR_MSG(npt, "unable to find interface #%u",
+			    lattrs->ifi_index);
+			return (ENOENT);
+		}
 	}
 
-	sx_slock(&rtnl_cloner_lock);
-	SLIST_FOREACH(cloner, &nl_cloners, next) {
-		if (!strcmp(attrs.ifla_cloner, cloner->name)) {
-			error = cloner->create_f(&attrs, nlp, npt);
-			sx_sunlock(&rtnl_cloner_lock);
-			return (error);
+	if (ifp == NULL && lattrs->ifla_ifname != NULL) {
+		ifp = ifunit_ref(lattrs->ifla_ifname);
+		if (ifp == NULL) {
+			NLMSG_REPORT_ERR_MSG(npt, "unable to find interface %s",
+			    lattrs->ifla_ifname);
+			return (ENOENT);
 		}
 	}
+
+	MPASS(ifp != NULL);
+
+	/*
+	 * There can be multiple kinds of interfaces:
+	 * 1) cloned, with additional options
+	 * 2) cloned, but w/o additional options
+	 * 3) non-cloned (e.g. "physical).
+	 *
+	 * Thus, try to find cloner-specific callback and fallback to the
+	 * "default" handler if not found.
+	 */
+	bool found = false;
+	int error = 0;
+
+	sx_slock(&rtnl_cloner_lock);
+	struct nl_cloner *cloner = rtnl_iface_find_cloner_locked(ifp->if_dname);
+	if (cloner != NULL) {
+		found = true;
+		error = cloner->modify_f(ifp, lattrs, bm, nlp, npt);
+	}
 	sx_sunlock(&rtnl_cloner_lock);
 
-	/* TODO: load cloner module if not exists & privilege permits */
-	NLMSG_REPORT_ERR_MSG(npt, "interface type %s not supported", attrs.ifla_cloner);
-	return (ENOTSUP);
+	if (!found)
+		error = generic_cloner.modify_f(ifp, lattrs, bm, nlp, npt);
+
+	if_rele(ifp);
 
 	return (error);
 }
 
+
+static int
+rtnl_handle_newlink(struct nlmsghdr *hdr, struct nlpcb *nlp, struct nl_pstate *npt)
+{
+	struct nlattr_bmask bm;
+	int error;
+
+	struct nl_parsed_link attrs = {};
+	error = nl_parse_nlmsg(hdr, &ifmsg_parser, npt, &attrs);
+	if (error != 0)
+		return (error);
+	nl_get_attrs_bmask_nlmsg(hdr, &ifmsg_parser, &bm);
+
+	if (hdr->nlmsg_flags & NLM_F_CREATE)
+		return (create_link(hdr, &attrs, &bm, nlp, npt));
+	else
+		return (modify_link(hdr, &attrs, &bm, nlp, npt));
+}
+
 /*
 
 {ifa_family=AF_INET, ifa_prefixlen=8, ifa_flags=IFA_F_PERMANENT, ifa_scope=RT_SCOPE_HOST, ifa_index=if_nametoindex("lo")},
@@ -863,13 +989,27 @@ rtnl_iface_add_cloner(struct nl_cloner *cloner)
 	sx_xunlock(&rtnl_cloner_lock);
 }
 
-void rtnl_iface_del_cloner(struct nl_cloner *cloner)
+void
+rtnl_iface_del_cloner(struct nl_cloner *cloner)
 {
 	sx_xlock(&rtnl_cloner_lock);
 	SLIST_REMOVE(&nl_cloners, cloner, nl_cloner, next);
 	sx_xunlock(&rtnl_cloner_lock);
 }
 
+static struct nl_cloner *
+rtnl_iface_find_cloner_locked(const char *name)
+{
+	struct nl_cloner *cloner;
+
+	SLIST_FOREACH(cloner, &nl_cloners, next) {
+		if (!strcmp(name, cloner->name))
+			return (cloner);
+	}
+
+	return (NULL);
+}
+
 void
 rtnl_ifaces_init(void)
 {
diff --git a/sys/netlink/route/iface_drivers.c b/sys/netlink/route/iface_drivers.c
index ccc8f2184fa3..7f098b808743 100644
--- a/sys/netlink/route/iface_drivers.c
+++ b/sys/netlink/route/iface_drivers.c
@@ -59,6 +59,95 @@ __FBSDID("$FreeBSD$");
 _DECLARE_DEBUG(LOG_DEBUG);
 
 /*
+ * Generic modification interface handler.
+ * Responsible for changing network stack interface attributes
+ * such as state, mtu or description.
+ */
+static int
+modify_generic(struct ifnet *ifp, struct nl_parsed_link *lattrs,
+    const struct nlattr_bmask *bm, struct nlpcb *nlp, struct nl_pstate *npt)
+{
+	int error;
+
+	if (lattrs->ifla_ifalias != NULL) {
+		if (nlp_has_priv(nlp, PRIV_NET_SETIFDESCR)) {
+			int len = strlen(lattrs->ifla_ifalias) + 1;
+			char *buf = if_allocdescr(len, true);
+
+			memcpy(buf, lattrs->ifla_ifalias, len);
+			if_setdescr(ifp, buf);
+			getmicrotime(&ifp->if_lastchange);
+		} else {
+			nlmsg_report_err_msg(npt, "Not enough privileges to set descr");
+			return (EPERM);
+		}
+	}
+
+	if ((lattrs->ifi_change & IFF_UP) && (lattrs->ifi_flags & IFF_UP) == 0) {
+		/* Request to down the interface */
+		if_down(ifp);
+	}
+
+	if (lattrs->ifla_mtu > 0) {
+		if (nlp_has_priv(nlp, PRIV_NET_SETIFMTU)) {
+			struct ifreq ifr = { .ifr_mtu = lattrs->ifla_mtu };
+			error = ifhwioctl(SIOCSIFMTU, ifp, (char *)&ifr, curthread);
+		} else {
+			nlmsg_report_err_msg(npt, "Not enough privileges to set mtu");
+			return (EPERM);
+		}
+	}
+
+	if (lattrs->ifi_change & IFF_PROMISC) {
+		error = ifpromisc(ifp, lattrs->ifi_flags & IFF_PROMISC);
+		if (error != 0) {
+			nlmsg_report_err_msg(npt, "unable to set promisc");
+			return (error);
+		}
+	}
+
+	return (0);
+}
+
+/*
+ * Generic creation interface handler.
+ * Responsible for creating interfaces w/o parameters and setting
+ * misc attributes such as state, mtu or description.
+ */
+static int
+create_generic(struct nl_parsed_link *lattrs, const struct nlattr_bmask *bm,
+    struct nlpcb *nlp, struct nl_pstate *npt)
+{
+	int error = 0;
+
+	struct ifc_data ifd = {};
+	struct ifnet *ifp = NULL;
+	error = ifc_create_ifp(lattrs->ifla_ifname, &ifd, &ifp);
+
+	NLP_LOG(LOG_DEBUG2, nlp, "clone for %s returned %d", lattrs->ifla_ifname, error);
+
+	if (error == 0) {
+		struct epoch_tracker et;
+
+		NET_EPOCH_ENTER(et);
+		bool success = if_try_ref(ifp);
+		NET_EPOCH_EXIT(et);
+		if (!success)
+			return (EINVAL);
+		error = modify_generic(ifp, lattrs, bm, nlp, npt);
+		if_rele(ifp);
+	}
+
+	return (error);
+}
+
+struct nl_cloner generic_cloner = {
+	.name = "_default_",
+	.create_f = create_generic,
+	.modify_f = modify_generic,
+};
+
+/*
  *
  * {len=76, type=RTM_NEWLINK, flags=NLM_F_REQUEST|NLM_F_ACK|NLM_F_EXCL|NLM_F_CREATE, seq=1662892737, pid=0},
  *  {ifi_family=AF_UNSPEC, ifi_type=ARPHRD_NETROM, ifi_index=0, ifi_flags=0, ifi_change=0},
@@ -87,7 +176,8 @@ static const struct nlattr_parser nla_p_vlan[] = {
 NL_DECLARE_ATTR_PARSER(vlan_parser, nla_p_vlan);
 
 static int
-create_vlan(struct nl_parsed_link *lattrs, struct nlpcb *nlp, struct nl_pstate *npt)
+create_vlan(struct nl_parsed_link *lattrs, const struct nlattr_bmask *bm,
+    struct nlpcb *nlp, struct nl_pstate *npt)
 {
 	struct epoch_tracker et;
         struct ifnet *ifp;
@@ -147,9 +237,17 @@ create_vlan(struct nl_parsed_link *lattrs, struct nlpcb *nlp, struct nl_pstate *
 	return (error);
 }
 
+static int
+dump_vlan(struct ifnet *ifp, struct nl_writer *nw)
+{
+	return (0);
+}
+
 static struct nl_cloner vlan_cloner = {
 	.name = "vlan",
 	.create_f = create_vlan,
+	.modify_f = modify_generic,
+	.dump_f = dump_vlan,
 
 };
 
diff --git a/sys/netlink/route/interface.h b/sys/netlink/route/interface.h
index 1b8f1cf7b53d..12a8aa718993 100644
--- a/sys/netlink/route/interface.h
+++ b/sys/netlink/route/interface.h
@@ -92,7 +92,7 @@ enum {
 #define IFLA_LINKINFO IFLA_LINKINFO
 	IFLA_NET_NS_PID	= 19,	/* u32: vnet id (not supported) */
 #define	IFLA_NET_NS_PID IFLA_NET_NS_PID
-	IFLA_IFALIAS	= 20,	/* not supported */
+	IFLA_IFALIAS	= 20,	/* string: interface description */
 #define	IFLA_IFALIAS IFLA_IFALIAS
 	IFLA_NUM_VF	= 21,	/* not supported */
 #define	IFLA_NUM_VF IFLA_NUM_VF
diff --git a/sys/netlink/route/route_var.h b/sys/netlink/route/route_var.h
index 0bcfcc962020..f1e522c7ae05 100644
--- a/sys/netlink/route/route_var.h
+++ b/sys/netlink/route/route_var.h
@@ -66,24 +66,31 @@ struct nl_parsed_link {
 	char		*ifla_group;
 	char		*ifla_ifname;
 	char		*ifla_cloner;
+	char		*ifla_ifalias;
 	struct nlattr	*ifla_idata;
 	unsigned short	ifi_type;
 	int		ifi_index;
 	uint32_t	ifla_mtu;
+	uint32_t	ifi_flags;
+	uint32_t	ifi_change;
 };
 
-typedef int rtnl_iface_create_f(struct nl_parsed_link *lattrs, struct nlpcb *nlp,
-    struct nl_pstate *npt);
-typedef int rtnl_iface_modify_f(struct nl_parsed_link *lattrs, struct nlpcb *nlp,
-    struct nl_pstate *npt);
+typedef int rtnl_iface_create_f(struct nl_parsed_link *lattrs,
+    const struct nlattr_bmask *bm, struct nlpcb *nlp, struct nl_pstate *npt);
+typedef int rtnl_iface_modify_f(struct ifnet *ifp, struct nl_parsed_link *lattrs,
+    const struct nlattr_bmask *bm, struct nlpcb *nlp, struct nl_pstate *npt);
+typedef int rtnl_iface_dump_f(struct ifnet *ifp, struct nl_writer *nw);
 
 struct nl_cloner {
 	const char		*name;
 	rtnl_iface_create_f	*create_f;
 	rtnl_iface_modify_f	*modify_f;
+	rtnl_iface_dump_f	*dump_f;
 	SLIST_ENTRY(nl_cloner)	next;
 };
 
+extern struct nl_cloner	generic_cloner;
+
 void rtnl_ifaces_init(void);
 void rtnl_ifaces_destroy(void);
 void rtnl_iface_add_cloner(struct nl_cloner *cloner);
diff --git a/tests/atf_python/sys/net/Makefile b/tests/atf_python/sys/net/Makefile
index 05b1d8afe863..63efefd27142 100644
--- a/tests/atf_python/sys/net/Makefile
+++ b/tests/atf_python/sys/net/Makefile
@@ -2,7 +2,7 @@
 
 .PATH:	${.CURDIR}
 
-FILES=	__init__.py rtsock.py tools.py vnet.py
+FILES=	__init__.py netlink.py rtsock.py tools.py vnet.py
 
 .include <bsd.own.mk>
 FILESDIR=	${TESTSBASE}/atf_python/sys/net
diff --git a/tests/atf_python/sys/net/netlink.py b/tests/atf_python/sys/net/netlink.py
new file mode 100644
index 000000000000..046519ce0343
--- /dev/null
+++ b/tests/atf_python/sys/net/netlink.py
@@ -0,0 +1,1495 @@
+#!/usr/local/bin/python3
+import os
+import socket
+import struct
+import sys
+import unittest
+from ctypes import c_int
+from ctypes import c_ubyte
+from ctypes import c_uint
+from ctypes import c_ushort
+from ctypes import sizeof
+from ctypes import Structure
+from enum import auto
+from enum import Enum
+from typing import Any
+from typing import Dict
+from typing import List
+from typing import NamedTuple
+
+
+def roundup2(val: int, num: int) -> int:
+    if val % num:
+        return (val | (num - 1)) + 1
+    else:
+        return val
+
+
+def align4(val: int) -> int:
+    return roundup2(val, 4)
+
+
+class SockaddrNl(Structure):
+    _fields_ = [
+        ("nl_len", c_ubyte),
+        ("nl_family", c_ubyte),
+        ("nl_pad", c_ushort),
+        ("nl_pid", c_uint),
+        ("nl_groups", c_uint),
+    ]
+
+
+class Nlmsghdr(Structure):
+    _fields_ = [
+        ("nlmsg_len", c_uint),
+        ("nlmsg_type", c_ushort),
+        ("nlmsg_flags", c_ushort),
+        ("nlmsg_seq", c_uint),
+        ("nlmsg_pid", c_uint),
+    ]
+
+
+class Nlmsgerr(Structure):
+    _fields_ = [
+        ("error", c_int),
+        ("msg", Nlmsghdr),
+    ]
+
+
+class NlErrattrType(Enum):
+    NLMSGERR_ATTR_UNUSED = 0
+    NLMSGERR_ATTR_MSG = auto()
+    NLMSGERR_ATTR_OFFS = auto()
+    NLMSGERR_ATTR_COOKIE = auto()
+    NLMSGERR_ATTR_POLICY = auto()
+
+
+class RtattrType(Enum):
+    RTA_UNSPEC = 0
+    RTA_DST = auto()
+    RTA_SRC = auto()
+    RTA_IIF = auto()
+    RTA_OIF = auto()
+    RTA_GATEWAY = auto()
+    RTA_PRIORITY = auto()
+    RTA_PREFSRC = auto()
+    RTA_METRICS = auto()
+    RTA_MULTIPATH = auto()
+    RTA_PROTOINFO = auto()
+    RTA_FLOW = auto()
+    RTA_CACHEINFO = auto()
+    RTA_SESSION = auto()
+    RTA_MP_ALGO = auto()
+    RTA_TABLE = auto()
+    RTA_MARK = auto()
+    RTA_MFC_STATS = auto()
+    RTA_VIA = auto()
+    RTA_NEWDST = auto()
+    RTA_PREF = auto()
+    RTA_ENCAP_TYPE = auto()
+    RTA_ENCAP = auto()
+    RTA_EXPIRES = auto()
+    RTA_PAD = auto()
+    RTA_UID = auto()
+    RTA_TTL_PROPAGATE = auto()
+    RTA_IP_PROTO = auto()
+    RTA_SPORT = auto()
+    RTA_DPORT = auto()
+    RTA_NH_ID = auto()
+
+
+class NlMsgType(Enum):
+    NLMSG_NOOP = 1
+    NLMSG_ERROR = 2
+    NLMSG_DONE = 3
+    NLMSG_OVERRUN = 4
+
+
+class NlRtMsgType(Enum):
+    RTM_NEWLINK = 16
+    RTM_DELLINK = 17
+    RTM_GETLINK = 18
+    RTM_SETLINK = 19
+    RTM_NEWADDR = 20
+    RTM_DELADDR = 21
+    RTM_GETADDR = 22
+    RTM_NEWROUTE = 24
+    RTM_DELROUTE = 25
+    RTM_GETROUTE = 26
+    RTM_NEWNEIGH = 28
+    RTM_DELNEIGH = 27
+    RTM_GETNEIGH = 28
+    RTM_NEWRULE = 32
+    RTM_DELRULE = 33
+    RTM_GETRULE = 34
+    RTM_NEWQDISC = 36
+    RTM_DELQDISC = 37
+    RTM_GETQDISC = 38
+    RTM_NEWTCLASS = 40
+    RTM_DELTCLASS = 41
+    RTM_GETTCLASS = 42
+    RTM_NEWTFILTER = 44
+    RTM_DELTFILTER = 45
+    RTM_GETTFILTER = 46
+    RTM_NEWACTION = 48
+    RTM_DELACTION = 49
+    RTM_GETACTION = 50
+    RTM_NEWPREFIX = 52
+    RTM_GETMULTICAST = 58
+    RTM_GETANYCAST = 62
+    RTM_NEWNEIGHTBL = 64
+    RTM_GETNEIGHTBL = 66
+    RTM_SETNEIGHTBL = 67
+    RTM_NEWNDUSEROPT = 68
+    RTM_NEWADDRLABEL = 72
+    RTM_DELADDRLABEL = 73
+    RTM_GETADDRLABEL = 74
+    RTM_GETDCB = 78
+    RTM_SETDCB = 79
+    RTM_NEWNETCONF = 80
+    RTM_GETNETCONF = 82
+    RTM_NEWMDB = 84
+    RTM_DELMDB = 85
+    RTM_GETMDB = 86
+    RTM_NEWNSID = 88
+    RTM_DELNSID = 89
+    RTM_GETNSID = 90
+    RTM_NEWSTATS = 92
+    RTM_GETSTATS = 94
+
+
+class RtAttr(Structure):
+    _fields_ = [
+        ("rta_len", c_ushort),
+        ("rta_type", c_ushort),
+    ]
+
+
+class RtMsgHdr(Structure):
+    _fields_ = [
+        ("rtm_family", c_ubyte),
+        ("rtm_dst_len", c_ubyte),
+        ("rtm_src_len", c_ubyte),
+        ("rtm_tos", c_ubyte),
+        ("rtm_table", c_ubyte),
+        ("rtm_protocol", c_ubyte),
+        ("rtm_scope", c_ubyte),
+        ("rtm_type", c_ubyte),
+        ("rtm_flags", c_uint),
+    ]
+
+
+class RtMsgFlags(Enum):
+    RTM_F_NOTIFY = 0x100
+    RTM_F_CLONED = 0x200
+    RTM_F_EQUALIZE = 0x400
+    RTM_F_PREFIX = 0x800
+    RTM_F_LOOKUP_TABLE = 0x1000
+    RTM_F_FIB_MATCH = 0x2000
+    RTM_F_OFFLOAD = 0x4000
+    RTM_F_TRAP = 0x8000
+    RTM_F_OFFLOAD_FAILED = 0x20000000
+
+
+class AddressFamilyLinux(Enum):
+    AF_INET = socket.AF_INET
+    AF_INET6 = socket.AF_INET6
+    AF_NETLINK = 16
+
+
+class AddressFamilyBsd(Enum):
+    AF_INET = socket.AF_INET
+    AF_INET6 = socket.AF_INET6
+    AF_NETLINK = 38
+
+
+class NlmBaseFlags(Enum):
+    NLM_F_REQUEST = 0x01
+    NLM_F_MULTI = 0x02
+    NLM_F_ACK = 0x04
+    NLM_F_ECHO = 0x08
+    NLM_F_DUMP_INTR = 0x10
+    NLM_F_DUMP_FILTERED = 0x20
+
+
+# XXX: in python3.8 it is possible to
+# class NlmGetFlags(Enum, NlmBaseFlags):
+
+
+class NlmGetFlags(Enum):
+    NLM_F_ROOT = 0x100
+    NLM_F_MATCH = 0x200
+    NLM_F_ATOMIC = 0x400
+
+
+class NlmNewFlags(Enum):
+    NLM_F_REPLACE = 0x100
+    NLM_F_EXCL = 0x200
+    NLM_F_CREATE = 0x400
+    NLM_F_APPEND = 0x800
+
+
+class NlmDeleteFlags(Enum):
+    NLM_F_NONREC = 0x100
+
+
+class NlmAckFlags(Enum):
+    NLM_F_CAPPED = 0x100
+    NLM_F_ACK_TLVS = 0x200
+
+
+class RtScope(Enum):
+    RT_SCOPE_UNIVERSE = 0
+    RT_SCOPE_SITE = 200
+    RT_SCOPE_LINK = 253
+    RT_SCOPE_HOST = 254
+    RT_SCOPE_NOWHERE = 255
+
+
+class RtType(Enum):
+    RTN_UNSPEC = 0
+    RTN_UNICAST = auto()
+    RTN_LOCAL = auto()
+    RTN_BROADCAST = auto()
+    RTN_ANYCAST = auto()
+    RTN_MULTICAST = auto()
+    RTN_BLACKHOLE = auto()
+    RTN_UNREACHABLE = auto()
+    RTN_PROHIBIT = auto()
+    RTN_THROW = auto()
+    RTN_NAT = auto()
+    RTN_XRESOLVE = auto()
+
+
+class RtProto(Enum):
+    RTPROT_UNSPEC = 0
+    RTPROT_REDIRECT = 1
+    RTPROT_KERNEL = 2
+    RTPROT_BOOT = 3
+    RTPROT_STATIC = 4
+    RTPROT_GATED = 8
+    RTPROT_RA = 9
+    RTPROT_MRT = 10
+    RTPROT_ZEBRA = 11
+    RTPROT_BIRD = 12
+    RTPROT_DNROUTED = 13
+    RTPROT_XORP = 14
+    RTPROT_NTK = 15
+    RTPROT_DHCP = 16
+    RTPROT_MROUTED = 17
+    RTPROT_KEEPALIVED = 18
+    RTPROT_BABEL = 42
+    RTPROT_OPENR = 99
+    RTPROT_BGP = 186
+    RTPROT_ISIS = 187
+    RTPROT_OSPF = 188
+    RTPROT_RIP = 189
+    RTPROT_EIGRP = 192
+
+
+class NlRtaxType(Enum):
+    RTAX_UNSPEC = 0
+    RTAX_LOCK = auto()
+    RTAX_MTU = auto()
+    RTAX_WINDOW = auto()
+    RTAX_RTT = auto()
+    RTAX_RTTVAR = auto()
+    RTAX_SSTHRESH = auto()
+    RTAX_CWND = auto()
+    RTAX_ADVMSS = auto()
+    RTAX_REORDERING = auto()
+    RTAX_HOPLIMIT = auto()
+    RTAX_INITCWND = auto()
+    RTAX_FEATURES = auto()
+    RTAX_RTO_MIN = auto()
+    RTAX_INITRWND = auto()
+    RTAX_QUICKACK = auto()
+    RTAX_CC_ALGO = auto()
+    RTAX_FASTOPEN_NO_COOKIE = auto()
+
+
+class NlRtGroup(Enum):
+    RTNLGRP_NONE = 0
+    RTNLGRP_LINK = auto()
+    RTNLGRP_NOTIFY = auto()
+    RTNLGRP_NEIGH = auto()
+    RTNLGRP_TC = auto()
+    RTNLGRP_IPV4_IFADDR = auto()
+    RTNLGRP_IPV4_MROUTE = auto()
+    RTNLGRP_IPV4_ROUTE = auto()
+    RTNLGRP_IPV4_RULE = auto()
+    RTNLGRP_IPV6_IFADDR = auto()
+    RTNLGRP_IPV6_MROUTE = auto()
+    RTNLGRP_IPV6_ROUTE = auto()
+    RTNLGRP_IPV6_IFINFO = auto()
+    RTNLGRP_DECnet_IFADDR = auto()
+    RTNLGRP_NOP2 = auto()
+    RTNLGRP_DECnet_ROUTE = auto()
+    RTNLGRP_DECnet_RULE = auto()
+    RTNLGRP_NOP4 = auto()
+    RTNLGRP_IPV6_PREFIX = auto()
+    RTNLGRP_IPV6_RULE = auto()
+    RTNLGRP_ND_USEROPT = auto()
+    RTNLGRP_PHONET_IFADDR = auto()
+    RTNLGRP_PHONET_ROUTE = auto()
+    RTNLGRP_DCB = auto()
+    RTNLGRP_IPV4_NETCONF = auto()
+    RTNLGRP_IPV6_NETCONF = auto()
+    RTNLGRP_MDB = auto()
+    RTNLGRP_MPLS_ROUTE = auto()
+    RTNLGRP_NSID = auto()
+    RTNLGRP_MPLS_NETCONF = auto()
+    RTNLGRP_IPV4_MROUTE_R = auto()
+    RTNLGRP_IPV6_MROUTE_R = auto()
+    RTNLGRP_NEXTHOP = auto()
+    RTNLGRP_BRVLAN = auto()
+
+
+class IfinfoMsg(Structure):
+    _fields_ = [
+        ("ifi_family", c_ubyte),
+        ("__ifi_pad", c_ubyte),
+        ("ifi_type", c_ushort),
+        ("ifi_index", c_int),
+        ("ifi_flags", c_uint),
+        ("ifi_change", c_uint),
+    ]
+
+
+class IflattrType(Enum):
+    IFLA_UNSPEC = 0
+    IFLA_ADDRESS = auto()
+    IFLA_BROADCAST = auto()
+    IFLA_IFNAME = auto()
+    IFLA_MTU = auto()
+    IFLA_LINK = auto()
+    IFLA_QDISC = auto()
+    IFLA_STATS = auto()
+    IFLA_COST = auto()
+    IFLA_PRIORITY = auto()
+    IFLA_MASTER = auto()
+    IFLA_WIRELESS = auto()
+    IFLA_PROTINFO = auto()
+    IFLA_TXQLEN = auto()
+    IFLA_MAP = auto()
+    IFLA_WEIGHT = auto()
+    IFLA_OPERSTATE = auto()
+    IFLA_LINKMODE = auto()
+    IFLA_LINKINFO = auto()
+    IFLA_NET_NS_PID = auto()
+    IFLA_IFALIAS = auto()
+    IFLA_NUM_VF = auto()
+    IFLA_VFINFO_LIST = auto()
+    IFLA_STATS64 = auto()
+    IFLA_VF_PORTS = auto()
+    IFLA_PORT_SELF = auto()
+    IFLA_AF_SPEC = auto()
+    IFLA_GROUP = auto()
+    IFLA_NET_NS_FD = auto()
+    IFLA_EXT_MASK = auto()
+    IFLA_PROMISCUITY = auto()
+    IFLA_NUM_TX_QUEUES = auto()
+    IFLA_NUM_RX_QUEUES = auto()
+    IFLA_CARRIER = auto()
+    IFLA_PHYS_PORT_ID = auto()
+    IFLA_CARRIER_CHANGES = auto()
+    IFLA_PHYS_SWITCH_ID = auto()
+    IFLA_LINK_NETNSID = auto()
+    IFLA_PHYS_PORT_NAME = auto()
+    IFLA_PROTO_DOWN = auto()
+    IFLA_GSO_MAX_SEGS = auto()
+    IFLA_GSO_MAX_SIZE = auto()
+    IFLA_PAD = auto()
+    IFLA_XDP = auto()
+    IFLA_EVENT = auto()
+    IFLA_NEW_NETNSID = auto()
+    IFLA_IF_NETNSID = auto()
+    IFLA_CARRIER_UP_COUNT = auto()
+    IFLA_CARRIER_DOWN_COUNT = auto()
+    IFLA_NEW_IFINDEX = auto()
+    IFLA_MIN_MTU = auto()
+    IFLA_MAX_MTU = auto()
+    IFLA_PROP_LIST = auto()
+    IFLA_ALT_IFNAME = auto()
+    IFLA_PERM_ADDRESS = auto()
+    IFLA_PROTO_DOWN_REASON = auto()
+
+
+class IflinkInfo(Enum):
+    IFLA_INFO_UNSPEC = 0
+    IFLA_INFO_KIND = auto()
+    IFLA_INFO_DATA = auto()
+    IFLA_INFO_XSTATS = auto()
+    IFLA_INFO_SLAVE_KIND = auto()
+    IFLA_INFO_SLAVE_DATA = auto()
+
+
+class IfLinkInfoDataVlan(Enum):
+    IFLA_VLAN_UNSPEC = 0
+    IFLA_VLAN_ID = auto()
+    IFLA_VLAN_FLAGS = auto()
+    IFLA_VLAN_EGRESS_QOS = auto()
+    IFLA_VLAN_INGRESS_QOS = auto()
+    IFLA_VLAN_PROTOCOL = auto()
+
+
+class IfaddrMsg(Structure):
+    _fields_ = [
+        ("ifa_family", c_ubyte),
+        ("ifa_prefixlen", c_ubyte),
+        ("ifa_flags", c_ubyte),
+        ("ifa_scope", c_ubyte),
+        ("ifa_index", c_uint),
+    ]
+
+
+class IfattrType(Enum):
+    IFA_UNSPEC = 0
+    IFA_ADDRESS = auto()
+    IFA_LOCAL = auto()
+    IFA_LABEL = auto()
+    IFA_BROADCAST = auto()
+    IFA_ANYCAST = auto()
+    IFA_CACHEINFO = auto()
+    IFA_MULTICAST = auto()
+    IFA_FLAGS = auto()
+    IFA_RT_PRIORITY = auto()
+    IFA_TARGET_NETNSID = auto()
+
+
+class GenlMsgHdr(Structure):
+    _fields_ = [
+        ("cmd", c_ubyte),
+        ("version", c_ubyte),
+        ("reserved", c_ushort),
+    ]
+
+
+class NlConst:
+    AF_NETLINK = 38
+    NETLINK_ROUTE = 0
+    NETLINK_GENERIC = 16
+
+
+class NlHelper:
+    def __init__(self):
+        self._pmap = {}
+        self._af_cls = self.get_af_cls()
+        self._seq_counter = 1
+        self.pid = os.getpid()
+
+    def get_seq(self):
+        ret = self._seq_counter
+        self._seq_counter += 1
+        return ret
+
+    def get_af_cls(self):
+        if sys.platform.startswith("freebsd"):
+            cls = AddressFamilyBsd
+        else:
+            cls = AddressFamilyLinux
+        return cls
+
+    def get_propmap(self, cls):
+        if cls not in self._pmap:
+            ret = {}
+            for prop in dir(cls):
+                if not prop.startswith("_"):
+                    ret[getattr(cls, prop).value] = prop
+            self._pmap[cls] = ret
+        return self._pmap[cls]
+
+    def get_name_propmap(self, cls):
+        ret = {}
+        for prop in dir(cls):
+            if not prop.startswith("_"):
+                ret[prop] = getattr(cls, prop).value
+        return ret
+
+    def get_attr_byval(self, cls, attr_val):
+        propmap = self.get_propmap(cls)
+        return propmap.get(attr_val)
+
+    def get_nlmsg_name(self, val):
+        for cls in [NlRtMsgType, NlMsgType]:
+            v = self.get_attr_byval(cls, val)
+            if v is not None:
+                return v
+        return "msg#{}".format(val)
+
+    def get_af_name(self, family):
+        v = self.get_attr_byval(self._af_cls, family)
+        if v is not None:
+            return v
+        return "af#{}".format(family)
+
+    def get_af_value(self, family_str: str) -> int:
+        propmap = self.get_name_propmap(self._af_cls)
+        return propmap.get(family_str)
+
+    def get_rta_name(self, val):
+        return self.get_attr_byval(RtattrType, val)
+
+    def get_bitmask_map(self, cls, val):
+        propmap = self.get_propmap(cls)
+        v = 1
+        ret = {}
+        while val:
+            if v & val:
+                if v in propmap:
+                    ret[v] = propmap[v]
+                else:
+                    ret[v] = hex(v)
+                val -= v
+            v *= 2
+        return ret
+
+    def get_bitmask_str(self, cls, val):
+        bmap = self.get_bitmask_map(cls, val)
+        return ",".join([v for k, v in bmap.items()])
+
+    def get_nlm_flags_str(self, msg_str: str, reply: bool, val):
+        if reply:
+            return self.get_bitmask_str(NlmAckFlags, val)
+        if msg_str.startswith("RTM_GET"):
+            return self.get_bitmask_str(NlmGetFlags, val)
+        elif msg_str.startswith("RTM_DEL"):
+            return self.get_bitmask_str(NlmDeleteFlags, val)
+        elif msg_str.startswith("RTM_NEW"):
+            return self.get_bitmask_str(NlmNewFlags, val)
+        else:
+            return self.get_bitmask_str(NlmBaseFlags, val)
+
+
+class NlAttr(object):
+    def __init__(self, nla_type, data):
+        if isinstance(nla_type, Enum):
+            self._nla_type = nla_type.value
+            self._enum = nla_type
+        else:
+            self._nla_type = nla_type
+            self._enum = None
+        self.nla_list = []
+        self._data = data
+
+    @property
+    def nla_type(self):
+        return self._nla_type & 0x3F
+
+    @property
+    def nla_len(self):
+        return len(self._data) + 4
+
+    def add_nla(self, nla):
+        self.nla_list.append(nla)
+
+    def print_attr(self, prepend=""):
+        if self._enum is not None:
+            type_str = self._enum.name
+        else:
+            type_str = "nla#{}".format(self.nla_type)
+        print(
+            "{}len={} type={}({}){}".format(
+                prepend, self.nla_len, type_str, self.nla_type, self._print_attr_value()
+            )
+        )
+
+    @staticmethod
+    def _validate(data):
+        if len(data) < 4:
+            raise ValueError("attribute too short")
+        nla_len, nla_type = struct.unpack("@HH", data[:4])
+        if nla_len > len(data):
+            raise ValueError("attribute length too big")
+        if nla_len < 4:
+            raise ValueError("attribute length too short")
+
+    @classmethod
+    def _parse(cls, data):
+        nla_len, nla_type = struct.unpack("@HH", data[:4])
+        return cls(nla_type, data[4:])
+
+    @classmethod
+    def from_bytes(cls, data, attr_type_enum=None):
+        cls._validate(data)
+        attr = cls._parse(data)
+        attr._enum = attr_type_enum
+        return attr
+
+    def _to_bytes(self, data: bytes):
+        ret = data
+        if align4(len(ret)) != len(ret):
+            ret = data + bytes(align4(len(ret)) - len(ret))
+        return struct.pack("@HH", len(data) + 4, self._nla_type) + ret
+
+    def __bytes__(self):
+        return self._to_bytes(self._data)
+
+    def _print_attr_value(self):
+        return " " + " ".join(["x{:02X}".format(b) for b in self._data])
+
+
+class NlAttrNested(NlAttr):
+    def __init__(self, nla_type, val):
+        super().__init__(nla_type, b"")
+        self.nla_list = val
+
+    @property
+    def nla_len(self):
+        return align4(len(b"".join([bytes(nla) for nla in self.nla_list]))) + 4
+
+    def print_attr(self, prepend=""):
+        if self._enum is not None:
+            type_str = self._enum.name
+        else:
+            type_str = "nla#{}".format(self.nla_type)
+        print(
+            "{}len={} type={}({}) {{".format(
+                prepend, self.nla_len, type_str, self.nla_type
+            )
+        )
+        for nla in self.nla_list:
+            nla.print_attr(prepend + "  ")
+        print("{}}}".format(prepend))
+
+    def __bytes__(self):
+        return self._to_bytes(b"".join([bytes(nla) for nla in self.nla_list]))
+
+
+class NlAttrU32(NlAttr):
+    def __init__(self, nla_type, val):
+        self.u32 = val
+        super().__init__(nla_type, b"")
+
+    @property
+    def nla_len(self):
+        return 8
+
+    def _print_attr_value(self):
+        return " val={}".format(self.u32)
+
+    @staticmethod
+    def _validate(data):
+        assert len(data) == 8
+        nla_len, nla_type = struct.unpack("@HH", data[:4])
+        assert nla_len == 8
+
+    @classmethod
+    def _parse(cls, data):
+        nla_len, nla_type, val = struct.unpack("@HHI", data)
+        return cls(nla_type, val)
+
+    def __bytes__(self):
+        return self._to_bytes(struct.pack("@I", self.u32))
+
+
+class NlAttrU16(NlAttr):
+    def __init__(self, nla_type, val):
+        self.u16 = val
+        super().__init__(nla_type, b"")
+
+    @property
+    def nla_len(self):
+        return 6
+
+    def _print_attr_value(self):
+        return " val={}".format(self.u16)
+
+    @staticmethod
+    def _validate(data):
+        assert len(data) == 6
+        nla_len, nla_type = struct.unpack("@HH", data[:4])
+        assert nla_len == 6
+
+    @classmethod
+    def _parse(cls, data):
+        nla_len, nla_type, val = struct.unpack("@HHH", data)
+        return cls(nla_type, val)
+
+    def __bytes__(self):
+        return self._to_bytes(struct.pack("@H", self.u16))
+
+
+class NlAttrU8(NlAttr):
+    def __init__(self, nla_type, val):
+        self.u8 = val
+        super().__init__(nla_type, b"")
+
+    @property
+    def nla_len(self):
+        return 5
+
+    def _print_attr_value(self):
+        return " val={}".format(self.u8)
+
+    @staticmethod
+    def _validate(data):
+        assert len(data) == 5
+        nla_len, nla_type = struct.unpack("@HH", data[:4])
+        assert nla_len == 5
+
+    @classmethod
+    def _parse(cls, data):
+        nla_len, nla_type, val = struct.unpack("@HHB", data)
+        return cls(nla_type, val)
+
+    def __bytes__(self):
+        return self._to_bytes(struct.pack("@B", self.u8))
+
+
+class NlAttrIp(NlAttr):
+    def __init__(self, nla_type, addr: str):
+        super().__init__(nla_type, b"")
+        self.addr = addr
+        if ":" in self.addr:
+            self.family = socket.AF_INET6
+        else:
+            self.family = socket.AF_INET
+
+    @staticmethod
+    def _validate(data):
+        nla_len, nla_type = struct.unpack("@HH", data[:4])
+        data_len = nla_len - 4
+        if data_len != 4 and data_len != 16:
+            raise ValueError(
+                "Error validating attr {}: nla_len is not valid".format(  # noqa: E501
+                    nla_type
+                )
+            )
+
+    @property
+    def nla_len(self):
+        if self.family == socket.AF_INET6:
+            return 20
+        else:
+            return 8
+        return align4(len(self._data)) + 4
+
+    @classmethod
+    def _parse(cls, data):
+        nla_len, nla_type = struct.unpack("@HH", data[:4])
+        data_len = len(data) - 4
+        if data_len == 4:
+            addr = socket.inet_ntop(socket.AF_INET, data[4:8])
+        else:
+            addr = socket.inet_ntop(socket.AF_INET6, data[4:20])
+        return cls(nla_type, addr)
+
+    def __bytes__(self):
+        return self._to_bytes(socket.inet_pton(self.family, self.addr))
+
+    def _print_attr_value(self):
+        return " addr={}".format(self.addr)
+
+
+class NlAttrIfindex(NlAttrU32):
+    def _print_attr_value(self):
+        try:
+            ifname = socket.if_indextoname(self.u32)
+            return " iface={}(#{})".format(ifname, self.u32)
+        except OSError:
+            pass
+        return " iface=if#{}".format(self.u32)
+
+
+class NlAttrTable(NlAttrU32):
+    def _print_attr_value(self):
+        return " rtable={}".format(self.u32)
+
+
+class NlAttrNhId(NlAttrU32):
+    def _print_attr_value(self):
+        return " nh_id={}".format(self.u32)
+
+
+class NlAttrMac(NlAttr):
+    def _print_attr_value(self):
+        return ' mac="' + ":".join(["{:02X}".format(b) for b in self._data]) + '"'
+
+
+class NlAttrIfStats(NlAttr):
+    def _print_attr_value(self):
+        return " stats={...}"
+
+
+class NlAttrVia(NlAttr):
+    def __init__(self, nla_type, family, addr: str):
+        super().__init__(nla_type, b"")
+        self.addr = addr
+        self.family = family
+
+    @staticmethod
+    def _validate(data):
+        nla_len, nla_type = struct.unpack("@HH", data[:4])
+        data_len = nla_len - 4
+        if data_len == 0:
+            raise ValueError(
+                "Error validating attr {}: empty data".format(nla_type)
+            )  # noqa: E501
+        family = int(data_len[0])
+        if family not in (socket.AF_INET, socket.AF_INET6):
+            raise ValueError(
+                "Error validating attr {}: unsupported AF {}".format(  # noqa: E501
+                    nla_type, family
+                )
+            )
+        if family == socket.AF_INET:
+            expected_len = 1 + 4
+        else:
+            expected_len = 1 + 16
+        if data_len != expected_len:
+            raise ValueError(
+                "Error validating attr {}: expected len {} got {}".format(  # noqa: E501
+                    nla_type, expected_len, data_len
+                )
+            )
+
+    @property
+    def nla_len(self):
+        if self.family == socket.AF_INET6:
+            return 21
+        else:
+            return 9
+
+    @classmethod
+    def _parse(cls, data):
+        nla_len, nla_type, family = struct.unpack("@HHB", data[:5])
+        off = 5
+        if family == socket.AF_INET:
+            addr = socket.inet_ntop(family, data[off : off + 4])
+        else:
+            addr = socket.inet_ntop(family, data[off : off + 16])
+        return cls(nla_type, family, addr)
+
+    def __bytes__(self):
+        addr = socket.inet_pton(self.family, self.addr)
+        return self._to_bytes(struct.pack("@B", self.family) + addr)
+
+    def _print_attr_value(self):
+        return " via={}".format(self.addr)
+
+
+class NlAttrStr(NlAttr):
+    def __init__(self, nla_type, text):
+        super().__init__(nla_type, b"")
+        self.text = text
+
+    @staticmethod
+    def _validate(data):
+        NlAttr._validate(data)
+        try:
+            data[4:].decode("utf-8")
+        except Exception as e:
+            raise ValueError("wrong utf-8 string: {}".format(e))
+
+    @property
+    def nla_len(self):
+        return len(self.text) + 5
+
+    @classmethod
+    def _parse(cls, data):
+        text = data[4:-1].decode("utf-8")
+        nla_len, nla_type = struct.unpack("@HH", data[:4])
+        return cls(nla_type, text)
+
+    def __bytes__(self):
+        return self._to_bytes(bytes(self.text, encoding="utf-8") + bytes(1))
+
+    def _print_attr_value(self):
+        return ' val="{}"'.format(self.text)
+
+
+class NlAttrStrn(NlAttr):
+    def __init__(self, nla_type, text):
+        super().__init__(nla_type, b"")
+        self.text = text
+
+    @staticmethod
+    def _validate(data):
+        NlAttr._validate(data)
+        try:
+            data[4:].decode("utf-8")
+        except Exception as e:
+            raise ValueError("wrong utf-8 string: {}".format(e))
+
+    @property
+    def nla_len(self):
+        return len(self.text) + 4
+
+    @classmethod
+    def _parse(cls, data):
+        text = data[4:].decode("utf-8")
+        nla_len, nla_type = struct.unpack("@HH", data[:4])
+        return cls(nla_type, text)
+
+    def __bytes__(self):
+        return self._to_bytes(bytes(self.text, encoding="utf-8"))
+
+    def _print_attr_value(self):
+        return ' val="{}"'.format(self.text)
+
+
+class AttrDescr(NamedTuple):
+    val: Enum
+    cls: NlAttr
+    child_map: Any = None
+
+
+def prepare_attrs_map(attrs: List[AttrDescr]) -> Dict[str, Dict]:
+    ret = {}
+    for ad in attrs:
+        ret[ad.val.value] = {"ad": ad}
+        if ad.child_map:
+            ret[ad.val.value]["child"] = prepare_attrs_map(ad.child_map)
+    return ret
+
+
+rtnl_route_attrs = [
+    AttrDescr(RtattrType.RTA_DST, NlAttrIp),
+    AttrDescr(RtattrType.RTA_SRC, NlAttrIp),
+    AttrDescr(RtattrType.RTA_IIF, NlAttrIfindex),
+    AttrDescr(RtattrType.RTA_OIF, NlAttrIfindex),
+    AttrDescr(RtattrType.RTA_GATEWAY, NlAttrTable),
+    AttrDescr(RtattrType.RTA_VIA, NlAttrVia),
+    AttrDescr(RtattrType.RTA_NH_ID, NlAttrNhId),
+    AttrDescr(
+        RtattrType.RTA_METRICS,
+        NlAttrNested,
+        [
+            AttrDescr(NlRtaxType.RTAX_MTU, NlAttrU32),
+        ],
+    ),
+]
+
+nlerr_attrs = [
+    AttrDescr(NlErrattrType.NLMSGERR_ATTR_MSG, NlAttrStr),
+    AttrDescr(NlErrattrType.NLMSGERR_ATTR_OFFS, NlAttrU32),
+]
+
+rtnl_ifla_attrs = [
+    AttrDescr(IflattrType.IFLA_ADDRESS, NlAttrMac),
+    AttrDescr(IflattrType.IFLA_BROADCAST, NlAttrMac),
+    AttrDescr(IflattrType.IFLA_IFNAME, NlAttrStr),
+    AttrDescr(IflattrType.IFLA_MTU, NlAttrU32),
+    AttrDescr(IflattrType.IFLA_PROMISCUITY, NlAttrU32),
+    AttrDescr(IflattrType.IFLA_OPERSTATE, NlAttrU8),
+    AttrDescr(IflattrType.IFLA_CARRIER, NlAttrU8),
+    AttrDescr(IflattrType.IFLA_IFALIAS, NlAttrStr),
+    AttrDescr(IflattrType.IFLA_STATS64, NlAttrIfStats),
+    AttrDescr(
+        IflattrType.IFLA_LINKINFO,
+        NlAttrNested,
+        [
+            AttrDescr(IflinkInfo.IFLA_INFO_KIND, NlAttrStr),
+            AttrDescr(IflinkInfo.IFLA_INFO_DATA, NlAttr),
+        ],
+    ),
+]
+
+rtnl_ifa_attrs = [
+    AttrDescr(IfattrType.IFA_ADDRESS, NlAttrIp),
+    AttrDescr(IfattrType.IFA_LOCAL, NlAttrIp),
+    AttrDescr(IfattrType.IFA_BROADCAST, NlAttrIp),
+    AttrDescr(IfattrType.IFA_ANYCAST, NlAttrIp),
+    AttrDescr(IfattrType.IFA_FLAGS, NlAttrU32),
+]
+
+
+class BaseNetlinkMessage(object):
+    def __init__(self, helper, nlmsg_type):
+        self.nlmsg_type = nlmsg_type
+        self.ut = unittest.TestCase()
+        self.nla_list = []
+        self._orig_data = None
+        self.helper = helper
+        self.nl_hdr = Nlmsghdr(
+            nlmsg_type=nlmsg_type, nlmsg_seq=helper.get_seq(), nlmsg_pid=helper.pid
+        )
+        self.base_hdr = None
+
+    def add_nla(self, nla):
+        self.nla_list.append(nla)
+
+    def _get_nla(self, nla_list, nla_type):
+        if isinstance(nla_type, Enum):
+            nla_type_raw = nla_type.value
+        else:
+            nla_type_raw = nla_type
+        for nla in nla_list:
+            if nla.nla_type == nla_type_raw:
+                return nla
+        return None
+
+    def get_nla(self, nla_type):
+        return self._get_nla(self.nla_list, nla_type)
+
+    @staticmethod
+    def parse_nl_header(data: bytes):
+        if len(data) < sizeof(Nlmsghdr):
+            raise ValueError("length less than netlink message header")
+        return Nlmsghdr.from_buffer_copy(data), sizeof(Nlmsghdr)
+
+    def is_type(self, nlmsg_type):
+        if isinstance(nlmsg_type, Enum):
+            nlmsg_type_raw = nlmsg_type.value
+        else:
+            nlmsg_type_raw = nlmsg_type
+        return nlmsg_type_raw == self.nl_hdr.nlmsg_type
+
+    def is_reply(self, hdr):
+        return hdr.nlmsg_type == NlMsgType.NLMSG_ERROR.value
+
+    def print_nl_header(self, hdr, prepend=""):
+        # len=44, type=RTM_DELROUTE, flags=NLM_F_REQUEST|NLM_F_ACK, seq=1641163704, pid=0  # noqa: E501
+        is_reply = self.is_reply(hdr)
+        msg_name = self.helper.get_nlmsg_name(hdr.nlmsg_type)
+        print(
+            "{}len={}, type={}, flags={}(0x{:X}), seq={}, pid={}".format(
+                prepend,
+                hdr.nlmsg_len,
+                msg_name,
+                self.helper.get_nlm_flags_str(
+                    msg_name, is_reply, hdr.nlmsg_flags
+                ),  # noqa: E501
+                hdr.nlmsg_flags,
+                hdr.nlmsg_seq,
+                hdr.nlmsg_pid,
+            )
+        )
+
+    @classmethod
+    def from_bytes(cls, helper, data):
+        try:
+            hdr, hdrlen = BaseNetlinkMessage.parse_nl_header(data)
+            self = cls(helper, hdr.nlmsg_type)
+            self._orig_data = data
+            self.nl_hdr = hdr
+        except ValueError as e:
+            print("Failed to parse nl header: {}".format(e))
+            cls.print_as_bytes(data)
+            raise
+        return self
+
+    def print_message(self):
+        self.print_nl_header(self.nl_hdr)
+
+    @staticmethod
+    def print_as_bytes(data: bytes, descr: str):
+        print("===vv {} (len:{:3d}) vv===".format(descr, len(data)))
+        off = 0
+        step = 16
+        while off < len(data):
+            for i in range(step):
+                if off + i < len(data):
+                    print(" {:02X}".format(data[off + i]), end="")
+            print("")
+            off += step
+        print("--------------------")
+
+
+class StdNetlinkMessage(BaseNetlinkMessage):
+    nl_attrs_map = {}
+
+    @classmethod
+    def from_bytes(cls, helper, data):
+        try:
+            hdr, hdrlen = BaseNetlinkMessage.parse_nl_header(data)
+            self = cls(helper, hdr.nlmsg_type)
+            self._orig_data = data
+            self.nl_hdr = hdr
+        except ValueError as e:
+            print("Failed to parse nl header: {}".format(e))
+            cls.print_as_bytes(data)
+            raise
+
+        offset = align4(hdrlen)
+        try:
+            base_hdr, hdrlen = self.parse_base_header(data[offset:])
+            self.base_hdr = base_hdr
+            offset += align4(hdrlen)
+            # XXX: CAP_ACK
+        except ValueError as e:
+            print("Failed to parse nl rt header: {}".format(e))
+            cls.print_as_bytes(data)
+            raise
+
+        orig_offset = offset
+        try:
+            nla_list, nla_len = self.parse_nla_list(data[offset:])
+            offset += nla_len
+            if offset != len(data):
+                raise ValueError(
+                    "{} bytes left at the end of the packet".format(len(data) - offset)
+                )  # noqa: E501
+            self.nla_list = nla_list
+        except ValueError as e:
+            print(
+                "Failed to parse nla attributes at offset {}: {}".format(orig_offset, e)
+            )  # noqa: E501
+            cls.print_as_bytes(data, "msg dump")
+            cls.print_as_bytes(data[orig_offset:], "failed block")
+            raise
+        return self
+
+    def _parse_attrs(self, data: bytes, attr_map):
+        ret = []
+        off = 0
+        while len(data) - off >= 4:
+            nla_len, raw_nla_type = struct.unpack("@HH", data[off : off + 4])
+            if nla_len + off > len(data):
+                raise ValueError(
+                    "attr length {} > than the remaining length {}".format(
+                        nla_len, len(data) - off
+                    )
+                )
+            nla_type = raw_nla_type & 0x3F
+            if nla_type in attr_map:
+                v = attr_map[nla_type]
+                val = v["ad"].cls.from_bytes(data[off : off + nla_len], v["ad"].val)
+                if "child" in v:
+                    # nested
+                    attrs, _ = self._parse_attrs(data[off : off + nla_len], v["child"])
+                    val = NlAttrNested(raw_nla_type, attrs)
+            else:
+                # unknown attribute
+                val = NlAttr(raw_nla_type, data[off + 4 : off + nla_len])
+            ret.append(val)
+            off += align4(nla_len)
+        return ret, off
+
+    def parse_nla_list(self, data: bytes) -> List[NlAttr]:
+        return self._parse_attrs(data, self.nl_attrs_map)
+
+    def print_message(self):
+        self.print_nl_header(self.nl_hdr)
+        self.print_base_header(self.base_hdr, " ")
+        for nla in self.nla_list:
+            nla.print_attr("  ")
+
+
+class NetlinkErrorMessage(StdNetlinkMessage):
+    messages = [NlMsgType.NLMSG_ERROR.value]
+    nl_attrs_map = prepare_attrs_map(nlerr_attrs)
+
+    @property
+    def error_code(self):
+        return self.base_hdr.error
+
+    @property
+    def error_str(self):
+        nla = self.get_nla(NlErrattrType.NLMSGERR_ATTR_MSG)
+        if nla:
+            return nla.text
+        return None
+
+    @property
+    def error_offset(self):
+        nla = self.get_nla(NlErrattrType.NLMSGERR_ATTR_OFFS)
+        if nla:
+            return nla.u32
+        return None
+
+    def parse_base_header(self, data):
+        if len(data) < sizeof(Nlmsgerr):
+            raise ValueError("length less than nlmsgerr header")
+        err_hdr = Nlmsgerr.from_buffer_copy(data)
+        sz = sizeof(Nlmsgerr)
+        if (self.nl_hdr.nlmsg_flags & 0x100) == 0:
+            sz += align4(err_hdr.msg.nlmsg_len - sizeof(Nlmsghdr))
+        return (err_hdr, sz)
+
+    def print_base_header(self, errhdr, prepend=""):
+        print("{}error={}, ".format(prepend, errhdr.error), end="")
+        self.print_nl_header(errhdr.msg, prepend)
+
+
+class BaseNetlinkRtMessage(StdNetlinkMessage):
+    def __init__(self, helper, nlm_type):
+        super().__init__(helper, nlm_type)
+        self.base_hdr = None
+
+    def __bytes__(self):
+        ret = bytes()
+        for nla in self.nla_list:
+            ret += bytes(nla)
+        ret = bytes(self.base_hdr) + ret
+        self.nl_hdr.nlmsg_len = len(ret) + sizeof(Nlmsghdr)
+        return bytes(self.nl_hdr) + ret
+
+    def print_message(self):
+        self.print_nl_header(self.nl_hdr)
+        self.print_base_header(self.base_hdr, " ")
+        for nla in self.nla_list:
+            nla.print_attr("  ")
+
+
+class NetlinkRtMessage(BaseNetlinkRtMessage):
+    messages = [
+        NlRtMsgType.RTM_NEWROUTE.value,
+        NlRtMsgType.RTM_DELROUTE.value,
+        NlRtMsgType.RTM_GETROUTE.value,
+    ]
+    nl_attrs_map = prepare_attrs_map(rtnl_route_attrs)
+
+    def __init__(self, helper, nlm_type):
+        super().__init__(helper, nlm_type)
+        self.base_hdr = RtMsgHdr()
+
+    def parse_base_header(self, data):
+        if len(data) < sizeof(RtMsgHdr):
+            raise ValueError("length less than rtmsg header")
+        rtm_hdr = RtMsgHdr.from_buffer_copy(data)
+        return (rtm_hdr, sizeof(RtMsgHdr))
+
+    def print_base_header(self, hdr, prepend=""):
+        family = self.helper.get_af_name(hdr.rtm_family)
+        print(
+            "{}family={}, dst_len={}, src_len={}, tos={}, table={}, protocol={}({}), scope={}({}), type={}({}), flags={}({})".format(  # noqa: E501
+                prepend,
+                family,
+                hdr.rtm_dst_len,
+                hdr.rtm_src_len,
+                hdr.rtm_tos,
+                hdr.rtm_table,
+                self.helper.get_attr_byval(RtProto, hdr.rtm_protocol),
+                hdr.rtm_protocol,
+                self.helper.get_attr_byval(RtScope, hdr.rtm_scope),
+                hdr.rtm_scope,
+                self.helper.get_attr_byval(RtType, hdr.rtm_type),
+                hdr.rtm_type,
+                self.helper.get_bitmask_str(RtMsgFlags, hdr.rtm_flags),
+                hdr.rtm_flags,
+            )
+        )
+
+
+class NetlinkIflaMessage(BaseNetlinkRtMessage):
+    messages = [
+        NlRtMsgType.RTM_NEWLINK.value,
+        NlRtMsgType.RTM_DELLINK.value,
+        NlRtMsgType.RTM_GETLINK.value,
+    ]
+    nl_attrs_map = prepare_attrs_map(rtnl_ifla_attrs)
+
+    def __init__(self, helper, nlm_type):
+        super().__init__(helper, nlm_type)
+        self.base_hdr = IfinfoMsg()
+
+    def parse_base_header(self, data):
+        if len(data) < sizeof(IfinfoMsg):
+            raise ValueError("length less than IfinfoMsg header")
+        rtm_hdr = IfinfoMsg.from_buffer_copy(data)
+        return (rtm_hdr, sizeof(IfinfoMsg))
+
+    def print_base_header(self, hdr, prepend=""):
+        family = self.helper.get_af_name(hdr.ifi_family)
+        print(
+            "{}family={}, ifi_type={}, ifi_index={}, ifi_flags={}, ifi_change={}".format(  # noqa: E501
+                prepend,
+                family,
+                hdr.ifi_type,
+                hdr.ifi_index,
+                hdr.ifi_flags,
+                hdr.ifi_change,
+            )
+        )
+
+
+class NetlinkIfaMessage(BaseNetlinkRtMessage):
+    messages = [
+        NlRtMsgType.RTM_NEWADDR.value,
+        NlRtMsgType.RTM_DELADDR.value,
+        NlRtMsgType.RTM_GETADDR.value,
+    ]
+    nl_attrs_map = prepare_attrs_map(rtnl_ifa_attrs)
+
+    def __init__(self, helper, nlm_type):
+        super().__init__(helper, nlm_type)
+        self.base_hdr = IfaddrMsg()
+
+    def parse_base_header(self, data):
+        if len(data) < sizeof(IfaddrMsg):
+            raise ValueError("length less than IfaddrMsg header")
+        rtm_hdr = IfaddrMsg.from_buffer_copy(data)
+        return (rtm_hdr, sizeof(IfaddrMsg))
+
+    def print_base_header(self, hdr, prepend=""):
+        family = self.helper.get_af_name(hdr.ifa_family)
+        print(
+            "{}family={}, ifa_prefixlen={}, ifa_flags={}, ifa_scope={}, ifa_index={}".format(  # noqa: E501
+                prepend,
+                family,
+                hdr.ifa_prefixlen,
+                hdr.ifa_flags,
+                hdr.ifa_scope,
+                hdr.ifa_index,
+            )
+        )
+
+
+class Nlsock:
+    def __init__(self, family, helper):
+        self.helper = helper
+        self.sock_fd = self._setup_netlink(family)
+        self._data = bytes()
+        self.msgmap = self.build_msgmap()
+        # self.set_groups(NlRtGroup.RTNLGRP_IPV4_ROUTE.value | NlRtGroup.RTNLGRP_IPV6_ROUTE.value)  # noqa: E501
+
+    def build_msgmap(self):
+        classes = [
+            NetlinkRtMessage,
+            NetlinkIflaMessage,
+            NetlinkIfaMessage,
+            NetlinkErrorMessage,
+        ]
+        xmap = {}
+        for cls in classes:
+            for message in cls.messages:
+                xmap[message] = cls
+        return xmap
+
+    def _setup_netlink(self, netlink_family) -> int:
+        family = self.helper.get_af_value("AF_NETLINK")
+        s = socket.socket(family, socket.SOCK_RAW, netlink_family)
+        s.setsockopt(270, 10, 1)  # NETLINK_CAP_ACK
+        s.setsockopt(270, 11, 1)  # NETLINK_EXT_ACK
+        return s
+
+    def set_groups(self, mask: int):
+        self.sock_fd.setsockopt(socket.SOL_SOCKET, 1, mask)
+        # snl = SockaddrNl(nl_len = sizeof(SockaddrNl), nl_family=38,
+        #                  nl_pid=self.pid, nl_groups=mask)
+        # xbuffer = create_string_buffer(sizeof(SockaddrNl))
+        # memmove(xbuffer, addressof(snl), sizeof(SockaddrNl))
+        # k = struct.pack("@BBHII", 12, 38, 0, self.pid, mask)
+        # self.sock_fd.bind(k)
+
+    def write_message(self, msg):
+        print("vvvvvvvv OUT vvvvvvvv")
+        msg.print_message()
+        msg_bytes = bytes(msg)
+        try:
+            ret = os.write(self.sock_fd.fileno(), msg_bytes)
+            assert ret == len(msg_bytes)
+        except Exception as e:
+            print("write({}) -> {}".format(len(msg_bytes), e))
+
+    def parse_message(self, data: bytes):
+        if len(data) < sizeof(Nlmsghdr):
+            raise Exception("Short read from nl: {} bytes".format(len(data)))
+        hdr = Nlmsghdr.from_buffer_copy(data)
+        nlmsg_type = hdr.nlmsg_type
+        cls = self.msgmap.get(nlmsg_type)
+        if not cls:
+            cls = BaseNetlinkMessage
+        return cls.from_bytes(self.helper, data)
+
+    def write_data(self, data: bytes):
+        self.sock_fd.send(data)
+
+    def read_data(self):
+        while True:
+            data = self.sock_fd.recv(65535)
+            self._data += data
+            if len(self._data) >= sizeof(Nlmsghdr):
+                break
+
+    def read_message(self) -> bytes:
+        if len(self._data) < sizeof(Nlmsghdr):
+            self.read_data()
+        hdr = Nlmsghdr.from_buffer_copy(self._data)
+        while hdr.nlmsg_len > len(self._data):
+            self.read_data()
+        raw_msg = self._data[: hdr.nlmsg_len]
+        self._data = self._data[hdr.nlmsg_len :]
+        return self.parse_message(raw_msg)
+
+    def request_ifaces(self):
+        msg = NetlinkIfaMessage(self.helper, NlRtMsgType.RTM_GETLINK.value)
+        flags = NlmGetFlags.NLM_F_ROOT.value | NlmGetFlags.NLM_F_MATCH.value
+        msg.nl_hdr.nlmsg_flags = flags | NlmBaseFlags.NLM_F_REQUEST.value
+
+        msg_bytes = bytes(msg)
+        x = self.parse_message(msg_bytes)
+        x.print_message()
+        print(msg_bytes)
+        # Skip family for now
+        self.write_data(msg_bytes)
+
+    def request_ifaddrs(self, family):
+        msg = NetlinkIfaMessage(self.helper, NlRtMsgType.RTM_GETADDR.value)
+        flags = NlmGetFlags.NLM_F_ROOT.value | NlmGetFlags.NLM_F_MATCH.value
+        msg.base_hdr.ifa_family = family
+        msg.nl_hdr.nlmsg_flags = flags | NlmBaseFlags.NLM_F_REQUEST.value
+
+        msg_bytes = bytes(msg)
+        x = self.parse_message(msg_bytes)
+        x.print_message()
+        print(msg_bytes)
+        # Skip family for now
+        self.write_data(msg_bytes)
+
+    def request_routes(self, family):
+        msg = NetlinkRtMessage(self.helper, NlRtMsgType.RTM_GETROUTE.value)
+        flags = NlmGetFlags.NLM_F_ROOT.value | NlmGetFlags.NLM_F_MATCH.value
+        msg.base_hdr.rtm_family = family
+        msg.nl_hdr.nlmsg_flags = flags | NlmBaseFlags.NLM_F_REQUEST.value
+
+        msg_bytes = bytes(msg)
+        x = self.parse_message(msg_bytes)
+        x.print_message()
+        print(msg_bytes)
+        # Skip family for now
+        self.write_data(msg_bytes)
+
+    def request_raw(self):
+        flags = NlmGetFlags.NLM_F_ROOT.value | NlmGetFlags.NLM_F_MATCH.value
+        hdr = Nlmsghdr(
+            nlmsg_type=NlRtMsgType.RTM_GETROUTE.value,
+            nlmsg_flags=flags | NlmBaseFlags.NLM_F_REQUEST.value,
+            nlmsg_len=sizeof(Nlmsghdr) + sizeof(RtMsgHdr) + 4,
+        )
+        rthdr = RtMsgHdr()
+
+        rta = RtAttr(rta_len=3, rta_type=RtattrType.RTA_OIF.value)
+
+        msg_bytes = bytes(hdr) + bytes(rthdr) + bytes(rta)
+        # x = self.parse_message(msg_bytes)
+        # x.print_message()
+        print(msg_bytes)
+        self.write_data(msg_bytes)
+
+    def request_families(self):
+        hdr = Nlmsghdr(
+            nlmsg_type=16,
+            nlmsg_flags=NlmBaseFlags.NLM_F_REQUEST.value,
+            nlmsg_len=sizeof(Nlmsghdr) + sizeof(GenlMsgHdr) + 4,
+        )
+        ghdr = GenlMsgHdr(cmd=3)
+
+        rta = RtAttr(rta_len=3, rta_type=RtattrType.RTA_OIF)
+
+        msg_bytes = bytes(hdr) + bytes(ghdr) + bytes(rta)
+        x = self.parse_message(msg_bytes)
+        x.print_message()
+        print(msg_bytes)
+        self.write_data(msg_bytes)
+
+
+def main():
+    helper = NlHelper()
+    if False:
+        nl = Nlsock(NlConst.NETLINK_GENERIC, helper)
+        nl.request_families()
+    else:
+        nl = Nlsock(NlConst.NETLINK_ROUTE, helper)
+        # nl.request_ifaddrs(socket.AF_INET)
+        # nl.request_raw()
+        nl.request_routes(0)
+        # nl.request_ifaces()
+    while True:
+        msg = nl.read_message()
+        print("")
+        msg.print_message()
+        msg.print_as_bytes(msg._orig_data, "-- DATA --")
+    pass
diff --git a/tests/sys/netlink/Makefile b/tests/sys/netlink/Makefile
new file mode 100644
index 000000000000..d05965761f62
--- /dev/null
+++ b/tests/sys/netlink/Makefile
@@ -0,0 +1,14 @@
+# $FreeBSD$
+
+PACKAGE=	tests
+WARNS?=		1
+
+TESTSDIR=       ${TESTSBASE}/sys/netlink
+
+#ATF_TESTS_C +=	test_rtsock_l3
+#ATF_TESTS_C +=	test_rtsock_lladdr
+ATF_TESTS_PYTEST +=	test_rtnl_iface.py
+
+CFLAGS+=	-I${.CURDIR:H:H:H}
+
+.include <bsd.test.mk>
diff --git a/tests/sys/netlink/test_rtnl_iface.py b/tests/sys/netlink/test_rtnl_iface.py
new file mode 100644
index 000000000000..38a3075f09c9
--- /dev/null
+++ b/tests/sys/netlink/test_rtnl_iface.py
@@ -0,0 +1,281 @@
+import errno
+import socket
+
+import pytest
+from atf_python.sys.net.netlink import IflattrType
+from atf_python.sys.net.netlink import IflinkInfo
+from atf_python.sys.net.netlink import IfLinkInfoDataVlan
+from atf_python.sys.net.netlink import NetlinkIflaMessage
+from atf_python.sys.net.netlink import NlAttrNested
+from atf_python.sys.net.netlink import NlAttrStr
+from atf_python.sys.net.netlink import NlAttrStrn
+from atf_python.sys.net.netlink import NlAttrU16
+from atf_python.sys.net.netlink import NlAttrU32
+from atf_python.sys.net.netlink import NlConst
+from atf_python.sys.net.netlink import NlHelper
+from atf_python.sys.net.netlink import NlmBaseFlags
+from atf_python.sys.net.netlink import NlmNewFlags
+from atf_python.sys.net.netlink import NlMsgType
+from atf_python.sys.net.netlink import NlRtMsgType
+from atf_python.sys.net.netlink import Nlsock
+from atf_python.sys.net.vnet import SingleVnetTestTemplate
+
+
+class TestRtNlIface(SingleVnetTestTemplate):
+    def setup_method(self, method):
+        super().setup_method(method)
+        self.helper = NlHelper()
+        self.nlsock = Nlsock(NlConst.NETLINK_ROUTE, self.helper)
+
+    def write_message(self, msg):
+        print("")
+        print("============= >> TX MESSAGE =============")
+        msg.print_message()
+        self.nlsock.write_data(bytes(msg))
+        msg.print_as_bytes(bytes(msg), "-- DATA --")
+
+    def read_message(self):
+        msg = self.nlsock.read_message()
+        print("")
+        print("============= << RX MESSAGE =============")
+        msg.print_message()
+        return msg
+
+    def get_reply(self, tx_msg):
+        self.write_message(tx_msg)
+        while True:
+            rx_msg = self.read_message()
+            if tx_msg.nl_hdr.nlmsg_seq == rx_msg.nl_hdr.nlmsg_seq:
+                return rx_msg
+
+    def get_interface_byname(self, ifname):
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_GETLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+        msg.add_nla(NlAttrStr(IflattrType.IFLA_IFNAME, ifname))
+        self.write_message(msg)
+        while True:
+            rx_msg = self.read_message()
+            if msg.nl_hdr.nlmsg_seq == rx_msg.nl_hdr.nlmsg_seq:
+                if rx_msg.is_type(NlMsgType.NLMSG_ERROR):
+                    if rx_msg.error_code != 0:
+                        raise ValueError("unable to get interface {}".format(ifname))
+                elif rx_msg.is_type(NlRtMsgType.RTM_NEWLINK):
+                    return rx_msg
+                else:
+                    raise ValueError("bad message")
+
+    def test_get_iface_byname_error(self):
+        """Tests error on fetching non-existing interface name"""
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_GETLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+        msg.add_nla(NlAttrStr(IflattrType.IFLA_IFNAME, "lo10"))
+
+        rx_msg = self.get_reply(msg)
+        assert rx_msg.is_type(NlMsgType.NLMSG_ERROR)
+        assert rx_msg.error_code == errno.ENODEV
+
+    def test_get_iface_byindex_error(self):
+        """Tests error on fetching non-existing interface index"""
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_GETLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+        msg.base_hdr.ifi_index = 2147483647
+
+        rx_msg = self.get_reply(msg)
+        assert rx_msg.is_type(NlMsgType.NLMSG_ERROR)
+        assert rx_msg.error_code == errno.ENODEV
+
+    @pytest.mark.require_user("root")
+    def test_create_iface_plain(self):
+        """Tests loopback creation w/o any parameters"""
+        flags = NlmNewFlags.NLM_F_EXCL.value | NlmNewFlags.NLM_F_CREATE.value
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_NEWLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            flags | NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+        msg.add_nla(NlAttrStr(IflattrType.IFLA_IFNAME, "lo10"))
+        msg.add_nla(
+            NlAttrNested(
+                IflattrType.IFLA_LINKINFO,
+                [
+                    NlAttrStrn(IflinkInfo.IFLA_INFO_KIND, "lo"),
+                ],
+            )
+        )
+
+        rx_msg = self.get_reply(msg)
+        assert rx_msg.is_type(NlMsgType.NLMSG_ERROR)
+        assert rx_msg.error_code == 0
+
+        self.get_interface_byname("lo10")
+
+    @pytest.mark.require_user("root")
+    def test_create_iface_attrs(self):
+        """Tests interface creation with additional properties"""
+        flags = NlmNewFlags.NLM_F_EXCL.value | NlmNewFlags.NLM_F_CREATE.value
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_NEWLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            flags | NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+        msg.add_nla(NlAttrStr(IflattrType.IFLA_IFNAME, "lo10"))
+        msg.add_nla(
+            NlAttrNested(
+                IflattrType.IFLA_LINKINFO,
+                [
+                    NlAttrStrn(IflinkInfo.IFLA_INFO_KIND, "lo"),
+                ],
+            )
+        )
+
+        # Custom attributes
+        msg.add_nla(NlAttrStr(IflattrType.IFLA_IFALIAS, "test description"))
+        msg.add_nla(NlAttrU32(IflattrType.IFLA_MTU, 1024))
+
+        rx_msg = self.get_reply(msg)
+        assert rx_msg.is_type(NlMsgType.NLMSG_ERROR)
+        assert rx_msg.error_code == 0
+
+        iface_msg = self.get_interface_byname("lo10")
+        assert iface_msg.get_nla(IflattrType.IFLA_IFALIAS).text == "test description"
+        assert iface_msg.get_nla(IflattrType.IFLA_MTU).u32 == 1024
+
+    @pytest.mark.require_user("root")
+    def test_modify_iface_attrs(self):
+        """Tests interface modifications"""
+        flags = NlmNewFlags.NLM_F_EXCL.value | NlmNewFlags.NLM_F_CREATE.value
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_NEWLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            flags | NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+        msg.add_nla(NlAttrStr(IflattrType.IFLA_IFNAME, "lo10"))
+        msg.add_nla(
+            NlAttrNested(
+                IflattrType.IFLA_LINKINFO,
+                [
+                    NlAttrStrn(IflinkInfo.IFLA_INFO_KIND, "lo"),
+                ],
+            )
+        )
+
+        rx_msg = self.get_reply(msg)
+        assert rx_msg.is_type(NlMsgType.NLMSG_ERROR)
+        assert rx_msg.error_code == 0
+
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_NEWLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+        msg.add_nla(NlAttrStr(IflattrType.IFLA_IFNAME, "lo10"))
+
+        # Custom attributes
+        msg.add_nla(NlAttrStr(IflattrType.IFLA_IFALIAS, "test description"))
+        msg.add_nla(NlAttrU32(IflattrType.IFLA_MTU, 1024))
+
+        rx_msg = self.get_reply(msg)
+        assert rx_msg.is_type(NlMsgType.NLMSG_ERROR)
+        assert rx_msg.error_code == 0
+
+        iface_msg = self.get_interface_byname("lo10")
+        assert iface_msg.get_nla(IflattrType.IFLA_IFALIAS).text == "test description"
+        assert iface_msg.get_nla(IflattrType.IFLA_MTU).u32 == 1024
+
+    @pytest.mark.require_user("root")
+    def test_delete_iface(self):
+        """Tests interface modifications"""
+        flags = NlmNewFlags.NLM_F_EXCL.value | NlmNewFlags.NLM_F_CREATE.value
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_NEWLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            flags | NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+        msg.add_nla(NlAttrStr(IflattrType.IFLA_IFNAME, "lo10"))
+        msg.add_nla(
+            NlAttrNested(
+                IflattrType.IFLA_LINKINFO,
+                [
+                    NlAttrStrn(IflinkInfo.IFLA_INFO_KIND, "lo"),
+                ],
+            )
+        )
+
+        rx_msg = self.get_reply(msg)
+        assert rx_msg.is_type(NlMsgType.NLMSG_ERROR)
+        assert rx_msg.error_code == 0
+
+        iface_msg = self.get_interface_byname("lo10")
+        iface_idx = iface_msg.base_hdr.ifi_index
+
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_DELLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+        msg.base_hdr.ifi_index = iface_idx
+        # msg.add_nla(NlAttrStr(IflattrType.IFLA_IFNAME, "lo10"))
+
+        rx_msg = self.get_reply(msg)
+        assert rx_msg.is_type(NlMsgType.NLMSG_ERROR)
+        assert rx_msg.error_code == 0
+
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_GETLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+        msg.base_hdr.ifi_index = 2147483647
+
+        rx_msg = self.get_reply(msg)
+        assert rx_msg.is_type(NlMsgType.NLMSG_ERROR)
+        assert rx_msg.error_code == errno.ENODEV
+
+    #
+    # *
+    # * {len=76, type=RTM_NEWLINK, flags=NLM_F_REQUEST|NLM_F_ACK|NLM_F_EXCL|NLM_F_CREATE, seq=1662892737, pid=0},
+    # *  {ifi_family=AF_UNSPEC, ifi_type=ARPHRD_NETROM, ifi_index=0, ifi_flags=0, ifi_change=0},
+    # *   [
+    # *    {{nla_len=8, nla_type=IFLA_LINK}, 2},
+    # *    {{nla_len=12, nla_type=IFLA_IFNAME}, "xvlan22"},
+    # *    {{nla_len=24, nla_type=IFLA_LINKINFO},
+    # *     [
+    # *      {{nla_len=8, nla_type=IFLA_INFO_KIND}, "vlan"...},
+    # *      {{nla_len=12, nla_type=IFLA_INFO_DATA}, "\x06\x00\x01\x00\x16\x00\x00\x00"}]}]}, iov_len=76}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 76
+    # */
+    @pytest.mark.skip(reason="vlan support needs more work")
+    @pytest.mark.require_user("root")
+    def test_create_vlan_plain(self):
+        """Creates 802.1Q VLAN interface in vlanXX and ifX fashion"""
+        os_ifname = self.vnet.iface_alias_map["if1"].name
+        ifindex = socket.if_nametoindex(os_ifname)
+
+        flags = NlmNewFlags.NLM_F_EXCL.value | NlmNewFlags.NLM_F_CREATE.value
+        msg = NetlinkIflaMessage(self.helper, NlRtMsgType.RTM_NEWLINK.value)
+        msg.nl_hdr.nlmsg_flags = (
+            flags | NlmBaseFlags.NLM_F_ACK.value | NlmBaseFlags.NLM_F_REQUEST.value
+        )
+
+        msg.add_nla(NlAttrU32(IflattrType.IFLA_LINK, ifindex))
+        msg.add_nla(NlAttrStr(IflattrType.IFLA_IFNAME, "vlan22"))
+
+        msg.add_nla(
+            NlAttrNested(
+                IflattrType.IFLA_LINKINFO,
+                [
+                    NlAttrStrn(IflinkInfo.IFLA_INFO_KIND, "vlan"),
+                    NlAttrNested(
+                        IflinkInfo.IFLA_INFO_DATA,
+                        [
+                            NlAttrU16(IfLinkInfoDataVlan.IFLA_VLAN_ID, 22),
+                        ],
+                    ),
+                ],
+            )
+        )
+
+        rx_msg = self.get_reply(msg)
+        assert rx_msg.is_type(NlMsgType.NLMSG_ERROR)
+        assert rx_msg.error_code == 0
+
+        self.get_interface_byname("vlan22")
+        # ToolsHelper.print_net_debug()