Merge branch 'ipv4-convert-rtm_-new-del-addr-and-more-to-per-netns-rtnl'

Kuniyuki Iwashima says:

====================
ipv4: Convert RTM_{NEW,DEL}ADDR and more to per-netns RTNL.

The IPv4 address hash table and GC are already namespacified.

This series converts RTM_NEWADDR/RTM_DELADDR and some more
RTNL users to per-netns RTNL.

Changes:
  v2:
    * Add patch 1 to address sparse warning for CONFIG_DEBUG_NET_SMALL_RTNL=n
    * Add Eric's tags to patch 2-12

  v1: https://lore.kernel.org/netdev/20241018012225.90409-1-kuniyu@amazon.com/
====================

Link: https://patch.msgid.link/20241021183239.79741-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

include/linux/inetdevice.h

@@ -226,6 +226,10 @@ static __inline__ bool bad_mask(__be32 mask, __be32 addr)
 	for (ifa = rtnl_dereference((in_dev)->ifa_list); ifa;	\
 	     ifa = rtnl_dereference(ifa->ifa_next))
 
+#define in_dev_for_each_ifa_rtnl_net(net, ifa, in_dev)			\
+	for (ifa = rtnl_net_dereference(net, (in_dev)->ifa_list); ifa;	\
+	     ifa = rtnl_net_dereference(net, ifa->ifa_next))
+
 #define in_dev_for_each_ifa_rcu(ifa, in_dev)			\
 	for (ifa = rcu_dereference((in_dev)->ifa_list); ifa;	\
 	     ifa = rcu_dereference(ifa->ifa_next))
@@ -252,6 +256,11 @@ static inline struct in_device *__in_dev_get_rtnl(const struct net_device *dev)
 	return rtnl_dereference(dev->ip_ptr);
 }
 
+static inline struct in_device *__in_dev_get_rtnl_net(const struct net_device *dev)
+{
+	return rtnl_net_dereference(dev_net(dev), dev->ip_ptr);
+}
+
 /* called with rcu_read_lock or rtnl held */
 static inline bool ip_ignore_linkdown(const struct net_device *dev)
 {

include/linux/rtnetlink.h

@@ -101,6 +101,7 @@ void __rtnl_net_lock(struct net *net);
 void __rtnl_net_unlock(struct net *net);
 void rtnl_net_lock(struct net *net);
 void rtnl_net_unlock(struct net *net);
+int rtnl_net_trylock(struct net *net);
 int rtnl_net_lock_cmp_fn(const struct lockdep_map *a, const struct lockdep_map *b);
 
 bool rtnl_net_is_locked(struct net *net);
@@ -132,26 +133,22 @@ static inline void rtnl_net_unlock(struct net *net)
 	rtnl_unlock();
 }
 
+static inline int rtnl_net_trylock(struct net *net)
+{
+	return rtnl_trylock();
+}
+
 static inline void ASSERT_RTNL_NET(struct net *net)
 {
 	ASSERT_RTNL();
 }
 
-static inline void *rcu_dereference_rtnl_net(struct net *net, void *p)
-{
-	return rcu_dereference_rtnl(p);
-}
-
-static inline void *rtnl_net_dereference(struct net *net, void *p)
-{
-	return rtnl_dereference(p);
-}
-
-static inline void *rcu_replace_pointer_rtnl_net(struct net *net,
-						 void *rp, void *p)
-{
-	return rcu_replace_pointer_rtnl(rp, p);
-}
+#define rcu_dereference_rtnl_net(net, p)		\
+	rcu_dereference_rtnl(p)
+#define rtnl_net_dereference(net, p)			\
+	rtnl_dereference(p)
+#define rcu_replace_pointer_rtnl_net(net, rp, p)	\
+	rcu_replace_pointer_rtnl(rp, p)
 #endif
 
 static inline struct netdev_queue *dev_ingress_queue(struct net_device *dev)

include/net/rtnetlink.h

@@ -12,6 +12,7 @@ typedef int (*rtnl_dumpit_func)(struct sk_buff *, struct netlink_callback *);
 
 enum rtnl_link_flags {
 	RTNL_FLAG_DOIT_UNLOCKED		= BIT(0),
+#define RTNL_FLAG_DOIT_PERNET		RTNL_FLAG_DOIT_UNLOCKED
 	RTNL_FLAG_BULK_DEL_SUPPORTED	= BIT(1),
 	RTNL_FLAG_DUMP_UNLOCKED		= BIT(2),
 	RTNL_FLAG_DUMP_SPLIT_NLM_DONE	= BIT(3),	/* legacy behavior */

net/core/dev_ioctl.c

@@ -64,7 +64,7 @@ int dev_ifconf(struct net *net, struct ifconf __user *uifc)
 	}
 
 	/* Loop over the interfaces, and write an info block for each. */
-	rtnl_lock();
+	rtnl_net_lock(net);
 	for_each_netdev(net, dev) {
 		if (!pos)
 			done = inet_gifconf(dev, NULL, 0, size);
@@ -72,12 +72,12 @@ int dev_ifconf(struct net *net, struct ifconf __user *uifc)
 			done = inet_gifconf(dev, pos + total,
 					    len - total, size);
 		if (done < 0) {
-			rtnl_unlock();
+			rtnl_net_unlock(net);
 			return -EFAULT;
 		}
 		total += done;
 	}
-	rtnl_unlock();
+	rtnl_net_unlock(net);
 
 	return put_user(total, &uifc->ifc_len);
 }

net/core/rtnetlink.c

@@ -210,6 +210,17 @@ void rtnl_net_unlock(struct net *net)
 }
 EXPORT_SYMBOL(rtnl_net_unlock);
 
+int rtnl_net_trylock(struct net *net)
+{
+	int ret = rtnl_trylock();
+
+	if (ret)
+		__rtnl_net_lock(net);
+
+	return ret;
+}
+EXPORT_SYMBOL(rtnl_net_trylock);
+
 static int rtnl_net_cmp_locks(const struct net *net_a, const struct net *net_b)
 {
 	if (net_eq(net_a, net_b))

net/ipv4/devinet.c

@@ -508,11 +508,6 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
 
 	ASSERT_RTNL();
 
-	if (!ifa->ifa_local) {
-		inet_free_ifa(ifa);
-		return 0;
-	}
-
 	ifa->ifa_flags &= ~IFA_F_SECONDARY;
 	last_primary = &in_dev->ifa_list;
 
@@ -584,14 +579,17 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
 
 static int inet_insert_ifa(struct in_ifaddr *ifa)
 {
+	if (!ifa->ifa_local) {
+		inet_free_ifa(ifa);
+		return 0;
+	}
+
 	return __inet_insert_ifa(ifa, NULL, 0, NULL);
 }
 
 static int inet_set_ifa(struct net_device *dev, struct in_ifaddr *ifa)
 {
-	struct in_device *in_dev = __in_dev_get_rtnl(dev);
-
-	ASSERT_RTNL();
+	struct in_device *in_dev = __in_dev_get_rtnl_net(dev);
 
 	ipv4_devconf_setall(in_dev);
 	neigh_parms_data_state_setall(in_dev->arp_parms);
@@ -645,7 +643,7 @@ static int ip_mc_autojoin_config(struct net *net, bool join,
 	struct sock *sk = net->ipv4.mc_autojoin_sk;
 	int ret;
 
-	ASSERT_RTNL();
+	ASSERT_RTNL_NET(net);
 
 	lock_sock(sk);
 	if (join)
@@ -671,22 +669,24 @@ static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
 	struct in_ifaddr *ifa;
 	int err;
 
-	ASSERT_RTNL();
-
 	err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
 				     ifa_ipv4_policy, extack);
 	if (err < 0)
-		goto errout;
+		goto out;
 
 	ifm = nlmsg_data(nlh);
+
+	rtnl_net_lock(net);
+
 	in_dev = inetdev_by_index(net, ifm->ifa_index);
 	if (!in_dev) {
 		NL_SET_ERR_MSG(extack, "ipv4: Device not found");
 		err = -ENODEV;
-		goto errout;
+		goto unlock;
 	}
 
-	for (ifap = &in_dev->ifa_list; (ifa = rtnl_dereference(*ifap)) != NULL;
+	for (ifap = &in_dev->ifa_list;
+	     (ifa = rtnl_net_dereference(net, *ifap)) != NULL;
 	     ifap = &ifa->ifa_next) {
 		if (tb[IFA_LOCAL] &&
 		    ifa->ifa_local != nla_get_in_addr(tb[IFA_LOCAL]))
@@ -702,13 +702,16 @@ static int inet_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 		if (ipv4_is_multicast(ifa->ifa_address))
 			ip_mc_autojoin_config(net, false, ifa);
+
 		__inet_del_ifa(in_dev, ifap, 1, nlh, NETLINK_CB(skb).portid);
-		return 0;
+		goto unlock;
 	}
 
 	NL_SET_ERR_MSG(extack, "ipv4: Address not found");
 	err = -EADDRNOTAVAIL;
-errout:
+unlock:
+	rtnl_net_unlock(net);
+out:
 	return err;
 }
 
@@ -766,7 +769,8 @@ static void check_lifetime(struct work_struct *work)
 		rcu_read_unlock();
 		if (!change_needed)
 			continue;
-		rtnl_lock();
+
+		rtnl_net_lock(net);
 		hlist_for_each_entry_safe(ifa, n, head, addr_lst) {
 			unsigned long age;
 
@@ -783,7 +787,7 @@ static void check_lifetime(struct work_struct *work)
 				struct in_ifaddr *tmp;
 
 				ifap = &ifa->ifa_dev->ifa_list;
-				tmp = rtnl_dereference(*ifap);
+				tmp = rtnl_net_dereference(net, *ifap);
 				while (tmp) {
 					if (tmp == ifa) {
 						inet_del_ifa(ifa->ifa_dev,
@@ -791,7 +795,7 @@ static void check_lifetime(struct work_struct *work)
 						break;
 					}
 					ifap = &tmp->ifa_next;
-					tmp = rtnl_dereference(*ifap);
+					tmp = rtnl_net_dereference(net, *ifap);
 				}
 			} else if (ifa->ifa_preferred_lft !=
 				   INFINITY_LIFE_TIME &&
@@ -801,7 +805,7 @@ static void check_lifetime(struct work_struct *work)
 				rtmsg_ifa(RTM_NEWADDR, ifa, NULL, 0);
 			}
 		}
-		rtnl_unlock();
+		rtnl_net_unlock(net);
 	}
 
 	next_sec = round_jiffies_up(next);
@@ -846,35 +850,54 @@ static void set_ifa_lifetime(struct in_ifaddr *ifa, __u32 valid_lft,
 		WRITE_ONCE(ifa->ifa_cstamp, ifa->ifa_tstamp);
 }
 
-static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh,
-				       __u32 *pvalid_lft, __u32 *pprefered_lft,
-				       struct netlink_ext_ack *extack)
+static int inet_validate_rtm(struct nlmsghdr *nlh, struct nlattr **tb,
+			     struct netlink_ext_ack *extack,
+			     __u32 *valid_lft, __u32 *prefered_lft)
 {
-	struct nlattr *tb[IFA_MAX+1];
-	struct in_ifaddr *ifa;
-	struct ifaddrmsg *ifm;
-	struct net_device *dev;
-	struct in_device *in_dev;
+	struct ifaddrmsg *ifm = nlmsg_data(nlh);
 	int err;
 
 	err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
 				     ifa_ipv4_policy, extack);
 	if (err < 0)
-		goto errout;
-
-	ifm = nlmsg_data(nlh);
-	err = -EINVAL;
+		return err;
 
 	if (ifm->ifa_prefixlen > 32) {
 		NL_SET_ERR_MSG(extack, "ipv4: Invalid prefix length");
-		goto errout;
+		return -EINVAL;
 	}
 
 	if (!tb[IFA_LOCAL]) {
 		NL_SET_ERR_MSG(extack, "ipv4: Local address is not supplied");
-		goto errout;
+		return -EINVAL;
 	}
 
+	if (tb[IFA_CACHEINFO]) {
+		struct ifa_cacheinfo *ci;
+
+		ci = nla_data(tb[IFA_CACHEINFO]);
+		if (!ci->ifa_valid || ci->ifa_prefered > ci->ifa_valid) {
+			NL_SET_ERR_MSG(extack, "ipv4: address lifetime invalid");
+			return -EINVAL;
+		}
+
+		*valid_lft = ci->ifa_valid;
+		*prefered_lft = ci->ifa_prefered;
+	}
+
+	return 0;
+}
+
+static struct in_ifaddr *inet_rtm_to_ifa(struct net *net, struct nlmsghdr *nlh,
+					 struct nlattr **tb,
+					 struct netlink_ext_ack *extack)
+{
+	struct ifaddrmsg *ifm = nlmsg_data(nlh);
+	struct in_device *in_dev;
+	struct net_device *dev;
+	struct in_ifaddr *ifa;
+	int err;
+
 	dev = __dev_get_by_index(net, ifm->ifa_index);
 	err = -ENODEV;
 	if (!dev) {
@@ -882,7 +905,7 @@ static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh,
 		goto errout;
 	}
 
-	in_dev = __in_dev_get_rtnl(dev);
+	in_dev = __in_dev_get_rtnl_net(dev);
 	err = -ENOBUFS;
 	if (!in_dev)
 		goto errout;
@@ -923,76 +946,69 @@ static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh,
 	if (tb[IFA_PROTO])
 		ifa->ifa_proto = nla_get_u8(tb[IFA_PROTO]);
 
-	if (tb[IFA_CACHEINFO]) {
-		struct ifa_cacheinfo *ci;
-
-		ci = nla_data(tb[IFA_CACHEINFO]);
-		if (!ci->ifa_valid || ci->ifa_prefered > ci->ifa_valid) {
-			NL_SET_ERR_MSG(extack, "ipv4: address lifetime invalid");
-			err = -EINVAL;
-			goto errout_free;
-		}
-		*pvalid_lft = ci->ifa_valid;
-		*pprefered_lft = ci->ifa_prefered;
-	}
-
 	return ifa;
 
-errout_free:
-	inet_free_ifa(ifa);
 errout:
 	return ERR_PTR(err);
 }
 
-static struct in_ifaddr *find_matching_ifa(struct in_ifaddr *ifa)
+static struct in_ifaddr *find_matching_ifa(struct net *net, struct in_ifaddr *ifa)
 {
 	struct in_device *in_dev = ifa->ifa_dev;
 	struct in_ifaddr *ifa1;
 
-	if (!ifa->ifa_local)
-		return NULL;
-
-	in_dev_for_each_ifa_rtnl(ifa1, in_dev) {
+	in_dev_for_each_ifa_rtnl_net(net, ifa1, in_dev) {
 		if (ifa1->ifa_mask == ifa->ifa_mask &&
 		    inet_ifa_match(ifa1->ifa_address, ifa) &&
 		    ifa1->ifa_local == ifa->ifa_local)
 			return ifa1;
 	}
+
 	return NULL;
 }
 
 static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
 			    struct netlink_ext_ack *extack)
 {
-	struct net *net = sock_net(skb->sk);
-	struct in_ifaddr *ifa;
-	struct in_ifaddr *ifa_existing;
-	__u32 valid_lft = INFINITY_LIFE_TIME;
 	__u32 prefered_lft = INFINITY_LIFE_TIME;
+	__u32 valid_lft = INFINITY_LIFE_TIME;
+	struct net *net = sock_net(skb->sk);
+	struct in_ifaddr *ifa_existing;
+	struct nlattr *tb[IFA_MAX + 1];
+	struct in_ifaddr *ifa;
+	int ret;
 
-	ASSERT_RTNL();
+	ret = inet_validate_rtm(nlh, tb, extack, &valid_lft, &prefered_lft);
+	if (ret < 0)
+		return ret;
 
-	ifa = rtm_to_ifaddr(net, nlh, &valid_lft, &prefered_lft, extack);
-	if (IS_ERR(ifa))
-		return PTR_ERR(ifa);
+	if (!nla_get_in_addr(tb[IFA_LOCAL]))
+		return 0;
 
-	ifa_existing = find_matching_ifa(ifa);
+	rtnl_net_lock(net);
+
+	ifa = inet_rtm_to_ifa(net, nlh, tb, extack);
+	if (IS_ERR(ifa)) {
+		ret = PTR_ERR(ifa);
+		goto unlock;
+	}
+
+	ifa_existing = find_matching_ifa(net, ifa);
 	if (!ifa_existing) {
 		/* It would be best to check for !NLM_F_CREATE here but
 		 * userspace already relies on not having to provide this.
 		 */
 		set_ifa_lifetime(ifa, valid_lft, prefered_lft);
 		if (ifa->ifa_flags & IFA_F_MCAUTOJOIN) {
-			int ret = ip_mc_autojoin_config(net, true, ifa);
-
+			ret = ip_mc_autojoin_config(net, true, ifa);
 			if (ret < 0) {
 				NL_SET_ERR_MSG(extack, "ipv4: Multicast auto join failed");
 				inet_free_ifa(ifa);
-				return ret;
+				goto unlock;
 			}
 		}
-		return __inet_insert_ifa(ifa, nlh, NETLINK_CB(skb).portid,
-					 extack);
+
+		ret = __inet_insert_ifa(ifa, nlh, NETLINK_CB(skb).portid, extack);
 	} else {
 		u32 new_metric = ifa->ifa_rt_priority;
 		u8 new_proto = ifa->ifa_proto;
@@ -1002,7 +1018,8 @@ static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
 		if (nlh->nlmsg_flags & NLM_F_EXCL ||
 		    !(nlh->nlmsg_flags & NLM_F_REPLACE)) {
 			NL_SET_ERR_MSG(extack, "ipv4: Address already assigned");
-			return -EEXIST;
+			ret = -EEXIST;
+			goto unlock;
 		}
 		ifa = ifa_existing;
 
@@ -1019,7 +1036,11 @@ static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
 				   &net->ipv4.addr_chk_work, 0);
 		rtmsg_ifa(RTM_NEWADDR, ifa, nlh, NETLINK_CB(skb).portid);
 	}
-	return 0;
+
+unlock:
+	rtnl_net_unlock(net);
+
+	return ret;
 }
 
 /*
@@ -1106,7 +1127,7 @@ int devinet_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr)
 		goto out;
 	}
 
-	rtnl_lock();
+	rtnl_net_lock(net);
 
 	ret = -ENODEV;
 	dev = __dev_get_by_name(net, ifr->ifr_name);
@@ -1116,7 +1137,7 @@ int devinet_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr)
 	if (colon)
 		*colon = ':';
 
-	in_dev = __in_dev_get_rtnl(dev);
+	in_dev = __in_dev_get_rtnl_net(dev);
 	if (in_dev) {
 		if (tryaddrmatch) {
 			/* Matthias Andree */
@@ -1126,7 +1147,7 @@ int devinet_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr)
 			   This is checked above. */
 
 			for (ifap = &in_dev->ifa_list;
-			     (ifa = rtnl_dereference(*ifap)) != NULL;
+			     (ifa = rtnl_net_dereference(net, *ifap)) != NULL;
 			     ifap = &ifa->ifa_next) {
 				if (!strcmp(ifr->ifr_name, ifa->ifa_label) &&
 				    sin_orig.sin_addr.s_addr ==
@@ -1140,7 +1161,7 @@ int devinet_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr)
 		   comparing just the label */
 		if (!ifa) {
 			for (ifap = &in_dev->ifa_list;
-			     (ifa = rtnl_dereference(*ifap)) != NULL;
+			     (ifa = rtnl_net_dereference(net, *ifap)) != NULL;
 			     ifap = &ifa->ifa_next)
 				if (!strcmp(ifr->ifr_name, ifa->ifa_label))
 					break;
@@ -1182,6 +1203,9 @@ int devinet_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr)
 				inet_del_ifa(in_dev, ifap, 1);
 			break;
 		}
+
+		/* NETDEV_UP/DOWN/CHANGE could touch a peer dev */
+		ASSERT_RTNL();
 		ret = dev_change_flags(dev, ifr->ifr_flags, NULL);
 		break;
 
@@ -1283,14 +1307,14 @@ int devinet_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr)
 		break;
 	}
 done:
-	rtnl_unlock();
+	rtnl_net_unlock(net);
 out:
 	return ret;
 }
 
 int inet_gifconf(struct net_device *dev, char __user *buf, int len, int size)
 {
-	struct in_device *in_dev = __in_dev_get_rtnl(dev);
+	struct in_device *in_dev = __in_dev_get_rtnl_net(dev);
 	const struct in_ifaddr *ifa;
 	struct ifreq ifr;
 	int done = 0;
@@ -1301,7 +1325,7 @@ int inet_gifconf(struct net_device *dev, char __user *buf, int len, int size)
 	if (!in_dev)
 		goto out;
 
-	in_dev_for_each_ifa_rtnl(ifa, in_dev) {
+	in_dev_for_each_ifa_rtnl_net(dev_net(dev), ifa, in_dev) {
 		if (!buf) {
 			done += size;
 			continue;
@@ -2372,7 +2396,7 @@ static void inet_forward_change(struct net *net)
 		if (on)
 			dev_disable_lro(dev);
 
-		in_dev = __in_dev_get_rtnl(dev);
+		in_dev = __in_dev_get_rtnl_net(dev);
 		if (in_dev) {
 			IN_DEV_CONF_SET(in_dev, FORWARDING, on);
 			inet_netconf_notify_devconf(net, RTM_NEWNETCONF,
@@ -2463,7 +2487,7 @@ static int devinet_sysctl_forward(const struct ctl_table *ctl, int write,
 
 	if (write && *valp != val) {
 		if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) {
-			if (!rtnl_trylock()) {
+			if (!rtnl_net_trylock(net)) {
 				/* Restore the original values before restarting */
 				*valp = val;
 				*ppos = pos;
@@ -2482,7 +2506,7 @@ static int devinet_sysctl_forward(const struct ctl_table *ctl, int write,
 							    idev->dev->ifindex,
 							    cnf);
 			}
-			rtnl_unlock();
+			rtnl_net_unlock(net);
 			rt_cache_flush(net);
 		} else
 			inet_netconf_notify_devconf(net, RTM_NEWNETCONF,
@@ -2813,8 +2837,10 @@ static struct rtnl_af_ops inet_af_ops __read_mostly = {
 };
 
 static const struct rtnl_msg_handler devinet_rtnl_msg_handlers[] __initconst = {
-	{.protocol = PF_INET, .msgtype = RTM_NEWADDR, .doit = inet_rtm_newaddr},
-	{.protocol = PF_INET, .msgtype = RTM_DELADDR, .doit = inet_rtm_deladdr},
+	{.protocol = PF_INET, .msgtype = RTM_NEWADDR, .doit = inet_rtm_newaddr,
+	 .flags = RTNL_FLAG_DOIT_PERNET},
+	{.protocol = PF_INET, .msgtype = RTM_DELADDR, .doit = inet_rtm_deladdr,
+	 .flags = RTNL_FLAG_DOIT_PERNET},
 	{.protocol = PF_INET, .msgtype = RTM_GETADDR, .dumpit = inet_dump_ifaddr,
 	 .flags = RTNL_FLAG_DUMP_UNLOCKED | RTNL_FLAG_DUMP_SPLIT_NLM_DONE},
 	{.protocol = PF_INET, .msgtype = RTM_GETNETCONF,