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authorTobias Waldekranz <tobias@waldekranz.com>2021-07-21 19:23:59 +0300
committerDavid S. Miller <davem@davemloft.net>2021-07-22 10:26:23 +0300
commitf7cf972f9375388838b0fbdaa007ce8494646990 (patch)
treef344d0e330eb0cb8478c8ece49e798955fc7bd06 /net/bridge/br_switchdev.c
parent45035febc49511d12e9687a83a3789767fe505e0 (diff)
downloadlinux-f7cf972f9375388838b0fbdaa007ce8494646990.tar.xz
net: bridge: disambiguate offload_fwd_mark
Before this change, four related - but distinct - concepts where named offload_fwd_mark: - skb->offload_fwd_mark: Set by the switchdev driver if the underlying hardware has already forwarded this frame to the other ports in the same hardware domain. - nbp->offload_fwd_mark: An idetifier used to group ports that share the same hardware forwarding domain. - br->offload_fwd_mark: Counter used to make sure that unique IDs are used in cases where a bridge contains ports from multiple hardware domains. - skb->cb->offload_fwd_mark: The hardware domain on which the frame ingressed and was forwarded. Introduce the term "hardware forwarding domain" ("hwdom") in the bridge to denote a set of ports with the following property: If an skb with skb->offload_fwd_mark set, is received on a port belonging to hwdom N, that frame has already been forwarded to all other ports in hwdom N. By decoupling the name from "offload_fwd_mark", we can extend the term's definition in the future - e.g. to add constraints that describe expected egress behavior - without overloading the meaning of "offload_fwd_mark". - nbp->offload_fwd_mark thus becomes nbp->hwdom. - br->offload_fwd_mark becomes br->last_hwdom. - skb->cb->offload_fwd_mark becomes skb->cb->src_hwdom. The slight change in naming here mandates a slight change in behavior of the nbp_switchdev_frame_mark() function. Previously, it only set this value in skb->cb for packets with skb->offload_fwd_mark true (ones which were forwarded in hardware). Whereas now we always track the incoming hwdom for all packets coming from a switchdev (even for the packets which weren't forwarded in hardware, such as STP BPDUs, IGMP reports etc). As all uses of skb->cb->offload_fwd_mark were already gated behind checks of skb->offload_fwd_mark, this will not introduce any functional change, but it paves the way for future changes where the ingressing hwdom must be known for frames coming from a switchdev regardless of whether they were forwarded in hardware or not (basically, if the skb comes from a switchdev, skb->cb->src_hwdom now always tracks which one). A typical example where this is relevant: the switchdev has a fixed configuration to trap STP BPDUs, but STP is not running on the bridge and the group_fwd_mask allows them to be forwarded. Say we have this setup: br0 / | \ / | \ swp0 swp1 swp2 A BPDU comes in on swp0 and is trapped to the CPU; the driver does not set skb->offload_fwd_mark. The bridge determines that the frame should be forwarded to swp{1,2}. It is imperative that forward offloading is _not_ allowed in this case, as the source hwdom is already "poisoned". Recording the source hwdom allows this case to be handled properly. v2->v3: added code comments v3->v6: none Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/bridge/br_switchdev.c')
-rw-r--r--net/bridge/br_switchdev.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
index d3adee0f91f9..833fd30482c2 100644
--- a/net/bridge/br_switchdev.c
+++ b/net/bridge/br_switchdev.c
@@ -8,20 +8,20 @@
#include "br_private.h"
-static int br_switchdev_mark_get(struct net_bridge *br, struct net_device *dev)
+static int br_switchdev_hwdom_get(struct net_bridge *br, struct net_device *dev)
{
struct net_bridge_port *p;
/* dev is yet to be added to the port list. */
list_for_each_entry(p, &br->port_list, list) {
if (netdev_port_same_parent_id(dev, p->dev))
- return p->offload_fwd_mark;
+ return p->hwdom;
}
- return ++br->offload_fwd_mark;
+ return ++br->last_hwdom;
}
-int nbp_switchdev_mark_set(struct net_bridge_port *p)
+int nbp_switchdev_hwdom_set(struct net_bridge_port *p)
{
struct netdev_phys_item_id ppid = { };
int err;
@@ -35,7 +35,7 @@ int nbp_switchdev_mark_set(struct net_bridge_port *p)
return err;
}
- p->offload_fwd_mark = br_switchdev_mark_get(p->br, p->dev);
+ p->hwdom = br_switchdev_hwdom_get(p->br, p->dev);
return 0;
}
@@ -43,15 +43,15 @@ int nbp_switchdev_mark_set(struct net_bridge_port *p)
void nbp_switchdev_frame_mark(const struct net_bridge_port *p,
struct sk_buff *skb)
{
- if (skb->offload_fwd_mark && !WARN_ON_ONCE(!p->offload_fwd_mark))
- BR_INPUT_SKB_CB(skb)->offload_fwd_mark = p->offload_fwd_mark;
+ if (p->hwdom)
+ BR_INPUT_SKB_CB(skb)->src_hwdom = p->hwdom;
}
bool nbp_switchdev_allowed_egress(const struct net_bridge_port *p,
const struct sk_buff *skb)
{
return !skb->offload_fwd_mark ||
- BR_INPUT_SKB_CB(skb)->offload_fwd_mark != p->offload_fwd_mark;
+ BR_INPUT_SKB_CB(skb)->src_hwdom != p->hwdom;
}
/* Flags that can be offloaded to hardware */