Merge branch 'rtnl-fdb-get'

Roopa Prabhu says:

====================
rtnl fdb get

This series adds support for rtnl fdb get similar to
route get.

v2: add nda_policy, fixes to exact msgs, strict nlmsg parsing

v3: remove unnecessary attribute length checks + simplify code
as pointed out by david
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 290 insertions, 2 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 49d4b5854c62..71c3b7b6b1ab 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1152,6 +1152,39 @@ out:
 	return err;
 }
 
+static int vxlan_fdb_get(struct sk_buff *skb,
+			 struct nlattr *tb[],
+			 struct net_device *dev,
+			 const unsigned char *addr,
+			 u16 vid, u32 portid, u32 seq,
+			 struct netlink_ext_ack *extack)
+{
+	struct vxlan_dev *vxlan = netdev_priv(dev);
+	struct vxlan_fdb *f;
+	__be32 vni;
+	int err;
+
+	if (tb[NDA_VNI])
+		vni = cpu_to_be32(nla_get_u32(tb[NDA_VNI]));
+	else
+		vni = vxlan->default_dst.remote_vni;
+
+	rcu_read_lock();
+
+	f = __vxlan_find_mac(vxlan, addr, vni);
+	if (!f) {
+		NL_SET_ERR_MSG(extack, "Fdb entry not found");
+		err = -ENOENT;
+		goto errout;
+	}
+
+	err = vxlan_fdb_info(skb, vxlan, f, portid, seq,
+			     RTM_NEWNEIGH, 0, first_remote_rcu(f));
+errout:
+	rcu_read_unlock();
+	return err;
+}
+
 /* Watch incoming packets to learn mapping between Ethernet address
  * and Tunnel endpoint.
  * Return true if packet is bogus and should be dropped.
@@ -2805,6 +2838,7 @@ static const struct net_device_ops vxlan_netdev_ether_ops = {
 	.ndo_fdb_add		= vxlan_fdb_add,
 	.ndo_fdb_del		= vxlan_fdb_delete,
 	.ndo_fdb_dump		= vxlan_fdb_dump,
+	.ndo_fdb_get		= vxlan_fdb_get,
 	.ndo_fill_metadata_dst	= vxlan_fill_metadata_dst,
 };
 
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 811632d4d8b1..1377d085ef99 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1387,7 +1387,12 @@ struct net_device_ops {
 						struct net_device *dev,
 						struct net_device *filter_dev,
 						int *idx);
-
+	int			(*ndo_fdb_get)(struct sk_buff *skb,
+					       struct nlattr *tb[],
+					       struct net_device *dev,
+					       const unsigned char *addr,
+					       u16 vid, u32 portid, u32 seq,
+					       struct netlink_ext_ack *extack);
 	int			(*ndo_bridge_setlink)(struct net_device *dev,
 						      struct nlmsghdr *nlh,
 						      u16 flags,
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 9f41a5d4da3f..013323b6dbe4 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -403,6 +403,7 @@ static const struct net_device_ops br_netdev_ops = {
 	.ndo_fdb_add		 = br_fdb_add,
 	.ndo_fdb_del		 = br_fdb_delete,
 	.ndo_fdb_dump		 = br_fdb_dump,
+	.ndo_fdb_get		 = br_fdb_get,
 	.ndo_bridge_getlink	 = br_getlink,
 	.ndo_bridge_setlink	 = br_setlink,
 	.ndo_bridge_dellink	 = br_dellink,
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 38b1d0dd0529..fe3c758791ca 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -773,6 +773,32 @@ skip:
 	return err;
 }
 
+int br_fdb_get(struct sk_buff *skb,
+	       struct nlattr *tb[],
+	       struct net_device *dev,
+	       const unsigned char *addr,
+	       u16 vid, u32 portid, u32 seq,
+	       struct netlink_ext_ack *extack)
+{
+	struct net_bridge *br = netdev_priv(dev);
+	struct net_bridge_fdb_entry *f;
+	int err = 0;
+
+	rcu_read_lock();
+	f = br_fdb_find_rcu(br, addr, vid);
+	if (!f) {
+		NL_SET_ERR_MSG(extack, "Fdb entry not found");
+		err = -ENOENT;
+		goto errout;
+	}
+
+	err = fdb_fill_info(skb, br, f, portid, seq,
+			    RTM_NEWNEIGH, 0);
+errout:
+	rcu_read_unlock();
+	return err;
+}
+
 /* Update (create or replace) forwarding database entry */
 static int fdb_add_entry(struct net_bridge *br, struct net_bridge_port *source,
 			 const u8 *addr, u16 state, u16 flags, u16 vid,
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index ff3dfb2a78b8..d240b3e7919f 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -575,6 +575,9 @@ int br_fdb_add(struct ndmsg *nlh, struct nlattr *tb[], struct net_device *dev,
 	       const unsigned char *addr, u16 vid, u16 nlh_flags);
 int br_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb,
 		struct net_device *dev, struct net_device *fdev, int *idx);
+int br_fdb_get(struct sk_buff *skb, struct nlattr *tb[], struct net_device *dev,
+	       const unsigned char *addr, u16 vid, u32 portid, u32 seq,
+	       struct netlink_ext_ack *extack);
 int br_fdb_sync_static(struct net_bridge *br, struct net_bridge_port *p);
 void br_fdb_unsync_static(struct net_bridge *br, struct net_bridge_port *p);
 int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f8bdb8adab2c..baf2685b4da2 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3460,6 +3460,18 @@ void rtmsg_ifinfo_newnet(int type, struct net_device *dev, unsigned int change,
 			   new_nsid, new_ifindex);
 }
 
+static const struct nla_policy nda_policy[NDA_MAX+1] = {
+	[NDA_DST]		= { .type = NLA_BINARY, .len = MAX_ADDR_LEN },
+	[NDA_LLADDR]		= { .type = NLA_BINARY, .len = MAX_ADDR_LEN },
+	[NDA_CACHEINFO]		= { .len = sizeof(struct nda_cacheinfo) },
+	[NDA_PROBES]		= { .type = NLA_U32 },
+	[NDA_VLAN]		= { .type = NLA_U16 },
+	[NDA_PORT]		= { .type = NLA_U16 },
+	[NDA_VNI]		= { .type = NLA_U32 },
+	[NDA_IFINDEX]		= { .type = NLA_U32 },
+	[NDA_MASTER]		= { .type = NLA_U32 },
+};
+
 static int nlmsg_populate_fdb_fill(struct sk_buff *skb,
 				   struct net_device *dev,
 				   u8 *addr, u16 vid, u32 pid, u32 seq,
@@ -4021,6 +4033,160 @@ out:
 	return skb->len;
 }
 
+static int valid_fdb_get_strict(const struct nlmsghdr *nlh,
+				struct nlattr **tb, u8 *ndm_flags,
+				int *br_idx, int *brport_idx, u8 **addr,
+				u16 *vid, struct netlink_ext_ack *extack)
+{
+	struct ndmsg *ndm;
+	int err, i;
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ndm))) {
+		NL_SET_ERR_MSG(extack, "Invalid header for fdb get request");
+		return -EINVAL;
+	}
+
+	ndm = nlmsg_data(nlh);
+	if (ndm->ndm_pad1  || ndm->ndm_pad2  || ndm->ndm_state ||
+	    ndm->ndm_type) {
+		NL_SET_ERR_MSG(extack, "Invalid values in header for fdb get request");
+		return -EINVAL;
+	}
+
+	if (ndm->ndm_flags & ~(NTF_MASTER | NTF_SELF)) {
+		NL_SET_ERR_MSG(extack, "Invalid flags in header for fdb get request");
+		return -EINVAL;
+	}
+
+	err = nlmsg_parse_strict(nlh, sizeof(struct ndmsg), tb, NDA_MAX,
+				 nda_policy, extack);
+	if (err < 0)
+		return err;
+
+	*ndm_flags = ndm->ndm_flags;
+	*brport_idx = ndm->ndm_ifindex;
+	for (i = 0; i <= NDA_MAX; ++i) {
+		if (!tb[i])
+			continue;
+
+		switch (i) {
+		case NDA_MASTER:
+			*br_idx = nla_get_u32(tb[i]);
+			break;
+		case NDA_LLADDR:
+			if (nla_len(tb[i]) != ETH_ALEN) {
+				NL_SET_ERR_MSG(extack, "Invalid address in fdb get request");
+				return -EINVAL;
+			}
+			*addr = nla_data(tb[i]);
+			break;
+		case NDA_VLAN:
+			err = fdb_vid_parse(tb[i], vid, extack);
+			if (err)
+				return err;
+			break;
+		case NDA_VNI:
+			break;
+		default:
+			NL_SET_ERR_MSG(extack, "Unsupported attribute in fdb get request");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int rtnl_fdb_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
+			struct netlink_ext_ack *extack)
+{
+	struct net_device *dev = NULL, *br_dev = NULL;
+	const struct net_device_ops *ops = NULL;
+	struct net *net = sock_net(in_skb->sk);
+	struct nlattr *tb[NDA_MAX + 1];
+	struct sk_buff *skb;
+	int brport_idx = 0;
+	u8 ndm_flags = 0;
+	int br_idx = 0;
+	u8 *addr = NULL;
+	u16 vid = 0;
+	int err;
+
+	err = valid_fdb_get_strict(nlh, tb, &ndm_flags, &br_idx,
+				   &brport_idx, &addr, &vid, extack);
+	if (err < 0)
+		return err;
+
+	if (brport_idx) {
+		dev = __dev_get_by_index(net, brport_idx);
+		if (!dev) {
+			NL_SET_ERR_MSG(extack, "Unknown device ifindex");
+			return -ENODEV;
+		}
+	}
+
+	if (br_idx) {
+		if (dev) {
+			NL_SET_ERR_MSG(extack, "Master and device are mutually exclusive");
+			return -EINVAL;
+		}
+
+		br_dev = __dev_get_by_index(net, br_idx);
+		if (!br_dev) {
+			NL_SET_ERR_MSG(extack, "Invalid master ifindex");
+			return -EINVAL;
+		}
+		ops = br_dev->netdev_ops;
+	}
+
+	if (dev) {
+		if (!ndm_flags || (ndm_flags & NTF_MASTER)) {
+			if (!(dev->priv_flags & IFF_BRIDGE_PORT)) {
+				NL_SET_ERR_MSG(extack, "Device is not a bridge port");
+				return -EINVAL;
+			}
+			br_dev = netdev_master_upper_dev_get(dev);
+			if (!br_dev) {
+				NL_SET_ERR_MSG(extack, "Master of device not found");
+				return -EINVAL;
+			}
+			ops = br_dev->netdev_ops;
+		} else {
+			if (!(ndm_flags & NTF_SELF)) {
+				NL_SET_ERR_MSG(extack, "Missing NTF_SELF");
+				return -EINVAL;
+			}
+			ops = dev->netdev_ops;
+		}
+	}
+
+	if (!br_dev && !dev) {
+		NL_SET_ERR_MSG(extack, "No device specified");
+		return -ENODEV;
+	}
+
+	if (!ops || !ops->ndo_fdb_get) {
+		NL_SET_ERR_MSG(extack, "Fdb get operation not supported by device");
+		return -EOPNOTSUPP;
+	}
+
+	skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!skb)
+		return -ENOBUFS;
+
+	if (br_dev)
+		dev = br_dev;
+	err = ops->ndo_fdb_get(skb, tb, dev, addr, vid,
+			       NETLINK_CB(in_skb).portid,
+			       nlh->nlmsg_seq, extack);
+	if (err)
+		goto out;
+
+	return rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
+out:
+	kfree_skb(skb);
+	return err;
+}
+
 static int brport_nla_put_flag(struct sk_buff *skb, u32 flags, u32 mask,
 			       unsigned int attrnum, unsigned int flag)
 {
@@ -5081,7 +5247,7 @@ void __init rtnetlink_init(void)
 
 	rtnl_register(PF_BRIDGE, RTM_NEWNEIGH, rtnl_fdb_add, NULL, 0);
 	rtnl_register(PF_BRIDGE, RTM_DELNEIGH, rtnl_fdb_del, NULL, 0);
-	rtnl_register(PF_BRIDGE, RTM_GETNEIGH, NULL, rtnl_fdb_dump, 0);
+	rtnl_register(PF_BRIDGE, RTM_GETNEIGH, rtnl_fdb_get, rtnl_fdb_dump, 0);
 
 	rtnl_register(PF_BRIDGE, RTM_GETLINK, NULL, rtnl_bridge_getlink, 0);
 	rtnl_register(PF_BRIDGE, RTM_DELLINK, rtnl_bridge_dellink, NULL, 0);
diff --git a/tools/testing/selftests/net/rtnetlink.sh b/tools/testing/selftests/net/rtnetlink.sh
index e101af52d1d6..bb3436f8807f 100755
--- a/tools/testing/selftests/net/rtnetlink.sh
+++ b/tools/testing/selftests/net/rtnetlink.sh
@@ -955,6 +955,58 @@ kci_test_ip6erspan()
 	ip netns del "$testns"
 }
 
+kci_test_fdb_get()
+{
+	IP="ip -netns testns"
+	BRIDGE="bridge -netns testns"
+	brdev="test-br0"
+	vxlandev="vxlan10"
+	test_mac=de:ad:be:ef:13:37
+	localip="10.0.2.2"
+	dstip="10.0.2.3"
+	ret=0
+
+	bridge fdb help 2>&1 |grep -q 'bridge fdb get'
+	if [ $? -ne 0 ];then
+		echo "SKIP: fdb get tests: iproute2 too old"
+		return $ksft_skip
+	fi
+
+	ip netns add testns
+	if [ $? -ne 0 ]; then
+		echo "SKIP fdb get tests: cannot add net namespace $testns"
+		return $ksft_skip
+	fi
+
+	$IP link add "$vxlandev" type vxlan id 10 local $localip \
+                dstport 4789 2>/dev/null
+	check_err $?
+	$IP link add name "$brdev" type bridge &>/dev/null
+	check_err $?
+	$IP link set dev "$vxlandev" master "$brdev" &>/dev/null
+	check_err $?
+	$BRIDGE fdb add $test_mac dev "$vxlandev" master &>/dev/null
+	check_err $?
+	$BRIDGE fdb add $test_mac dev "$vxlandev" dst $dstip self &>/dev/null
+	check_err $?
+
+	$BRIDGE fdb get $test_mac brport "$vxlandev" 2>/dev/null | grep -q "dev $vxlandev master $brdev"
+	check_err $?
+	$BRIDGE fdb get $test_mac br "$brdev" 2>/dev/null | grep -q "dev $vxlandev master $brdev"
+	check_err $?
+	$BRIDGE fdb get $test_mac dev "$vxlandev" self 2>/dev/null | grep -q "dev $vxlandev dst $dstip"
+	check_err $?
+
+	ip netns del testns &>/dev/null
+
+	if [ $ret -ne 0 ]; then
+		echo "FAIL: bridge fdb get"
+		return 1
+	fi
+
+	echo "PASS: bridge fdb get"
+}
+
 kci_test_rtnl()
 {
 	kci_add_dummy
@@ -979,6 +1031,7 @@ kci_test_rtnl()
 	kci_test_macsec
 	kci_test_ipsec
 	kci_test_ipsec_offload
+	kci_test_fdb_get
 
 	kci_del_dummy
 }