[RFC PATCH net-next 10/11] net: vlan: disallow non-Ethernet devices

[Edwin Peer <edwin.peer@broadcom.com>]

Layering VLANs on top of non-Ethernet devices is not defined. This
prevents nonsensical combinations like VLANs on top of raw IP in
IP tunnels, for example.

Checking the device type means that some devices no longer need to
explicitly set NETIF_F_VLAN_CHALLENGED. Remove this flags from those
devices where this is trivially the case.

The failover device does not explicitly check device types when adding
slaves (team and bonding drivers do), so include the device type check
when VLANs are in use too.

TEQL scheduling devices have historically allowed VLANs and this change
would break that. Inherit the slave device's type instead of ARPHRD_VOID
and enforce that all slaves have the same type.

IFB devices do not have a normal xmit function and so VLAN devices
cannot forward frames (packets must be redirected). IFB devices are
also IFF_NOARP, so we can set the device type accordingly to disable
support for VLANs. Similarly the SB1000 is RX only.

VLANs don't make sense for VRF devices because they are raw IP. Relying
on NETIF_F_VLAN_CHALLENGED is unnecessary if the device type is set
appropriately.

Signed-off-by: Edwin Peer <edwin.peer@broadcom.com>
---
 drivers/infiniband/ulp/ipoib/ipoib_main.c   | 3 +--
 drivers/net/ethernet/xilinx/ll_temac_main.c | 1 -
 drivers/net/ifb.c                           | 4 ++++
 drivers/net/loopback.c                      | 1 -
 drivers/net/net_failover.c                  | 3 +--
 drivers/net/sb1000.c                        | 1 +
 drivers/net/vrf.c                           | 4 +---
 include/linux/if_vlan.h                     | 8 ++++++++
 net/8021q/vlan.c                            | 2 +-
 net/sched/sch_teql.c                        | 3 +++
 10 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index 81b8227214f1..a4404957b39b 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -2086,8 +2086,7 @@ void ipoib_setup_common(struct net_device *dev)
 	dev->addr_len		 = INFINIBAND_ALEN;
 	dev->type		 = ARPHRD_INFINIBAND;
 	dev->tx_queue_len	 = ipoib_sendq_size * 2;
-	dev->features		 = (NETIF_F_VLAN_CHALLENGED	|
-				    NETIF_F_HIGHDMA);
+	dev->features		 = NETIF_F_HIGHDMA;
 	netif_keep_dst(dev);
 
 	memcpy(dev->broadcast, ipv4_bcast_addr, INFINIBAND_ALEN);
diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c
index 929244064abd..731326d1e99f 100644
--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -1375,7 +1375,6 @@ static int temac_probe(struct platform_device *pdev)
 	ndev->features |= NETIF_F_HW_VLAN_CTAG_TX; /* Transmit VLAN hw accel */
 	ndev->features |= NETIF_F_HW_VLAN_CTAG_RX; /* Receive VLAN hw acceleration */
 	ndev->features |= NETIF_F_HW_VLAN_CTAG_FILTER; /* Receive VLAN filtering */
-	ndev->features |= NETIF_F_VLAN_CHALLENGED; /* cannot handle VLAN pkts */
 	ndev->features |= NETIF_F_GSO; /* Enable software GSO. */
 	ndev->features |= NETIF_F_MULTI_QUEUE; /* Has multiple TX/RX queues */
 	ndev->features |= NETIF_F_LRO; /* large receive offload */
diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
index 7fe306e76281..3ac6b4282113 100644
--- a/drivers/net/ifb.c
+++ b/drivers/net/ifb.c
@@ -213,6 +213,10 @@ static void ifb_setup(struct net_device *dev)
 
 	/* Fill in device structure with ethernet-generic values. */
 	ether_setup(dev);
+
+	/* Override ARPHRD_ETHER to disallow upper VLAN devices (no xmit). */
+	dev->type = ARPHRD_NONE;
+
 	dev->tx_queue_len = TX_Q_LIMIT;
 
 	dev->features |= IFB_FEATURES;
diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index a1c77cc00416..59c7aa726245 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -183,7 +183,6 @@ static void gen_lo_setup(struct net_device *dev,
 		| NETIF_F_HIGHDMA
 		| NETIF_F_LLTX
 		| NETIF_F_NETNS_LOCAL
-		| NETIF_F_VLAN_CHALLENGED
 		| NETIF_F_LOOPBACK;
 	dev->ethtool_ops	= eth_ops;
 	dev->header_ops		= hdr_ops;
diff --git a/drivers/net/net_failover.c b/drivers/net/net_failover.c
index a085d292b4cf..78ef32642c85 100644
--- a/drivers/net/net_failover.c
+++ b/drivers/net/net_failover.c
@@ -496,8 +496,7 @@ static int net_failover_slave_pre_register(struct net_device *slave_dev,
 				  !dev_is_pci(slave_dev->dev.parent)))
 		return -EINVAL;
 
-	if (failover_dev->features & NETIF_F_VLAN_CHALLENGED &&
-	    vlan_uses_dev(failover_dev)) {
+	if (vlan_challenged(failover_dev) && vlan_uses_dev(failover_dev)) {
 		netdev_err(failover_dev, "Device %s is VLAN challenged and failover device has VLAN set up\n",
 			   failover_dev->name);
 		return -EINVAL;
diff --git a/drivers/net/sb1000.c b/drivers/net/sb1000.c
index e88af978f63c..0cb3fb563160 100644
--- a/drivers/net/sb1000.c
+++ b/drivers/net/sb1000.c
@@ -192,6 +192,7 @@ sb1000_probe_one(struct pnp_dev *pdev, const struct pnp_device_id *id)
 	 * The SB1000 is an rx-only cable modem device.  The uplink is a modem
 	 * and we do not want to arp on it.
 	 */
+	dev->type = ARPHRD_NONE;
 	dev->flags = IFF_POINTOPOINT|IFF_NOARP;
 
 	SET_NETDEV_DEV(dev, &pdev->dev);
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 43928a1c2f2a..f490f3cfa358 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -860,6 +860,7 @@ static int vrf_dev_init(struct net_device *dev)
 	if (vrf_rt6_create(dev) != 0)
 		goto out_rth;
 
+	dev->type = ARPHRD_RAWIP;
 	dev->flags = IFF_MASTER | IFF_NOARP;
 
 	/* MTU is irrelevant for VRF device; set to 64k similar to lo */
@@ -1271,9 +1272,6 @@ static void vrf_setup(struct net_device *dev)
 	/* don't allow vrf devices to change network namespaces. */
 	dev->features |= NETIF_F_NETNS_LOCAL;
 
-	/* does not make sense for a VLAN to be added to a vrf device */
-	dev->features   |= NETIF_F_VLAN_CHALLENGED;
-
 	/* enable offload features */
 	dev->features   |= NETIF_F_GSO_SOFTWARE;
 	dev->features   |= NETIF_F_RXCSUM | NETIF_F_HW_CSUM | NETIF_F_SCTP_CRC;
diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index e4a5532fb179..7c2781ec7013 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -12,6 +12,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/bug.h>
 #include <uapi/linux/if_vlan.h>
+#include <uapi/linux/if_arp.h>
 
 #define VLAN_HLEN	4		/* The additional bytes required by VLAN
 					 * (in addition to the Ethernet header)
@@ -789,4 +790,11 @@ static inline void vlan_constrain_mtu(struct net_device *dev)
  */
 int vlan_constrained_change_mtu(struct net_device *dev, int new_mtu);
 
+/* in addition to NETIF_F_VLAN_CHALLENGED, non-Ethernet devices can't VLAN */
+static inline bool vlan_challenged(struct net_device *dev)
+{
+	return dev->type != ARPHRD_ETHER ||
+	       dev->features & NETIF_F_VLAN_CHALLENGED;
+}
+
 #endif /* !(_LINUX_IF_VLAN_H_) */
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index d4bcfd8f95bf..eb162b020ec9 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -127,7 +127,7 @@ int vlan_check_real_dev(struct net_device *real_dev,
 {
 	const char *name = real_dev->name;
 
-	if (real_dev->features & NETIF_F_VLAN_CHALLENGED) {
+	if (vlan_challenged(real_dev)) {
 		pr_info("VLANs not supported on %s\n", name);
 		NL_SET_ERR_MSG_MOD(extack, "VLANs not supported on device");
 		return -EOPNOTSUPP;
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index 689ef6f3ded8..7ef08bd16b24 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -181,6 +181,8 @@ static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt,
 	skb_queue_head_init(&q->q);
 
 	if (m->slaves) {
+		if (m->dev->type != dev->type)
+			return -EINVAL;
 		if (m->dev->flags & IFF_UP) {
 			if ((m->dev->flags & IFF_POINTOPOINT &&
 			     !(dev->flags & IFF_POINTOPOINT)) ||
@@ -205,6 +207,7 @@ static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt,
 	} else {
 		q->next = sch;
 		m->slaves = sch;
+		m->dev->type = dev->type;
 		m->dev->mtu = dev->mtu;
 		m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
 	}
-- 
2.26.2