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authorVladimir Oltean <vladimir.oltean@nxp.com>2020-05-10 19:37:40 +0300
committerJakub Kicinski <kuba@kernel.org>2020-05-11 05:52:33 +0300
commit9eb8eff0cf2f1e1afc0756bb30cb9746ba90dd07 (patch)
tree6b41633b856834a8cc2a05bdfde065475b19f702 /net/bridge
parent90d9834ecd6b92880765cbcafba373ce33a7cb05 (diff)
downloadlinux-9eb8eff0cf2f1e1afc0756bb30cb9746ba90dd07.tar.xz
net: bridge: allow enslaving some DSA master network devices
Commit 8db0a2ee2c63 ("net: bridge: reject DSA-enabled master netdevices as bridge members") added a special check in br_if.c in order to check for a DSA master network device with a tagging protocol configured. This was done because back then, such devices, once enslaved in a bridge would become inoperative and would not pass DSA tagged traffic anymore due to br_handle_frame returning RX_HANDLER_CONSUMED. But right now we have valid use cases which do require bridging of DSA masters. One such example is when the DSA master ports are DSA switch ports themselves (in a disjoint tree setup). This should be completely equivalent, functionally speaking, from having multiple DSA switches hanging off of the ports of a switchdev driver. So we should allow the enslaving of DSA tagged master network devices. Instead of the regular br_handle_frame(), install a new function br_handle_frame_dummy() on these DSA masters, which returns RX_HANDLER_PASS in order to call into the DSA specific tagging protocol handlers, and lift the restriction from br_add_if. Suggested-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Suggested-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Tested-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/bridge')
-rw-r--r--net/bridge/br_if.c32
-rw-r--r--net/bridge/br_input.c23
-rw-r--r--net/bridge/br_private.h6
3 files changed, 48 insertions, 13 deletions
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index ca685c0cdf95..a0e9a7937412 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -563,18 +563,32 @@ int br_add_if(struct net_bridge *br, struct net_device *dev,
unsigned br_hr, dev_hr;
bool changed_addr;
- /* 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.
- */
+ /* Don't allow bridging non-ethernet like devices. */
if ((dev->flags & IFF_LOOPBACK) ||
dev->type != ARPHRD_ETHER || dev->addr_len != ETH_ALEN ||
- !is_valid_ether_addr(dev->dev_addr) ||
- netdev_uses_dsa(dev))
+ !is_valid_ether_addr(dev->dev_addr))
return -EINVAL;
+ /* Also don't allow bridging of net devices that are DSA masters, since
+ * the bridge layer rx_handler prevents the DSA fake ethertype handler
+ * to be invoked, so we don't get the chance to strip off and parse the
+ * DSA switch tag protocol header (the bridge layer just returns
+ * RX_HANDLER_CONSUMED, stopping RX processing for these frames).
+ * The only case where that would not be an issue is when bridging can
+ * already be offloaded, such as when the DSA master is itself a DSA
+ * or plain switchdev port, and is bridged only with other ports from
+ * the same hardware device.
+ */
+ if (netdev_uses_dsa(dev)) {
+ list_for_each_entry(p, &br->port_list, list) {
+ if (!netdev_port_same_parent_id(dev, p->dev)) {
+ NL_SET_ERR_MSG(extack,
+ "Cannot do software bridging with a DSA master");
+ return -EINVAL;
+ }
+ }
+ }
+
/* No bridging of bridges */
if (dev->netdev_ops->ndo_start_xmit == br_dev_xmit) {
NL_SET_ERR_MSG(extack,
@@ -618,7 +632,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev,
if (err)
goto err3;
- err = netdev_rx_handler_register(dev, br_handle_frame, p);
+ err = netdev_rx_handler_register(dev, br_get_rx_handler(dev), p);
if (err)
goto err4;
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index d5c34f36f0f4..59a318b9f646 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -17,6 +17,7 @@
#endif
#include <linux/neighbour.h>
#include <net/arp.h>
+#include <net/dsa.h>
#include <linux/export.h>
#include <linux/rculist.h>
#include "br_private.h"
@@ -257,7 +258,7 @@ frame_finish:
* Return NULL if skb is handled
* note: already called with rcu_read_lock
*/
-rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
+static rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
{
struct net_bridge_port *p;
struct sk_buff *skb = *pskb;
@@ -359,3 +360,23 @@ drop:
}
return RX_HANDLER_CONSUMED;
}
+
+/* This function has no purpose other than to appease the br_port_get_rcu/rtnl
+ * helpers which identify bridged ports according to the rx_handler installed
+ * on them (so there _needs_ to be a bridge rx_handler even if we don't need it
+ * to do anything useful). This bridge won't support traffic to/from the stack,
+ * but only hardware bridging. So return RX_HANDLER_PASS so we don't steal
+ * frames from the ETH_P_XDSA packet_type handler.
+ */
+static rx_handler_result_t br_handle_frame_dummy(struct sk_buff **pskb)
+{
+ return RX_HANDLER_PASS;
+}
+
+rx_handler_func_t *br_get_rx_handler(const struct net_device *dev)
+{
+ if (netdev_uses_dsa(dev))
+ return br_handle_frame_dummy;
+
+ return br_handle_frame;
+}
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 4dc21e8f7e33..7501be4eeba0 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -702,16 +702,16 @@ int nbp_backup_change(struct net_bridge_port *p, struct net_device *backup_dev);
/* br_input.c */
int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb);
-rx_handler_result_t br_handle_frame(struct sk_buff **pskb);
+rx_handler_func_t *br_get_rx_handler(const struct net_device *dev);
static inline bool br_rx_handler_check_rcu(const struct net_device *dev)
{
- return rcu_dereference(dev->rx_handler) == br_handle_frame;
+ return rcu_dereference(dev->rx_handler) == br_get_rx_handler(dev);
}
static inline bool br_rx_handler_check_rtnl(const struct net_device *dev)
{
- return rcu_dereference_rtnl(dev->rx_handler) == br_handle_frame;
+ return rcu_dereference_rtnl(dev->rx_handler) == br_get_rx_handler(dev);
}
static inline struct net_bridge_port *br_port_get_check_rcu(const struct net_device *dev)