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authorFlorian Fainelli <f.fainelli@gmail.com>2015-01-16 09:56:02 -0800
committerDavid S. Miller <davem@davemloft.net>2015-01-19 15:45:10 -0500
commit8db0a2ee2c6302a1dcbcdb93cb731dfc6c0cdb5e (patch)
tree73b836097d22b1c91acaaa5441180f47756a2658 /net/bridge/br_if.c
parent728c02089a0e3eefb02e9927bfae50490f40e72e (diff)
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net: bridge: reject DSA-enabled master netdevices as bridge members
DSA-enabled master network devices with a switch tagging protocol should strip the protocol specific format before handing the frame over to higher layer. When adding such a DSA master network device as a bridge member, we go through the following code path when receiving a frame: __netif_receive_skb_core -> first ptype check against ptype_all is not returning any handler for this skb -> check and invoke rx_handler: -> deliver frame to the bridge layer: br_handle_frame DSA registers a ptype handler with the fake ETH_XDSA ethertype, which is called *after* the bridge-layer rx_handler has run. br_handle_frame() tries to parse the frame it received from the DSA master network device, and will not be able to match any of its conditions and jumps straight at the end of the end of br_handle_frame() and returns RX_HANDLER_CONSUMED there. Since we returned RX_HANDLER_CONSUMED, __netif_receive_skb_core() stops RX processing for this frame and returns NET_RX_SUCCESS, so we never get a chance to call our switch tag packet processing logic and deliver frames to the DSA slave network devices, and so we do not get any functional bridge members at all. Instead of cluttering the bridge receive path with DSA-specific checks, and rely on assumptions about how __netif_receive_skb_core() is processing frames, we simply deny adding the DSA master network device (conduit interface) as a bridge member, leaving only the slave DSA network devices to be bridge members, since those will work correctly in all circumstances. Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge/br_if.c')
-rw-r--r--net/bridge/br_if.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 81e49fb..b087d27 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -436,10 +436,16 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
int err = 0;
bool changed_addr;
- /* Don't allow bridging non-ethernet like devices */
+ /* Don't allow bridging non-ethernet like devices, or DSA-enabled
+ * master network devices since the bridge layer rx_handler prevents
+ * the DSA fake ethertype handler to be invoked, so we do not strip off
+ * the DSA switch tag protocol header and the bridge layer just return
+ * RX_HANDLER_CONSUMED, stopping RX processing for these frames.
+ */
if ((dev->flags & IFF_LOOPBACK) ||
dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
- !is_valid_ether_addr(dev->dev_addr))
+ !is_valid_ether_addr(dev->dev_addr) ||
+ netdev_uses_dsa(dev))
return -EINVAL;
/* No bridging of bridges */
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