[PATCH net-next] net/bridge: add drop reasons for bridge forwarding
From: yang.yang29
Date: Thu Apr 06 2023 - 07:30:45 EST
From: xu xin <xu.xin16@xxxxxxxxxx>
This creates six drop reasons as follows, which will help users know the
specific reason why bridge drops the packets when forwarding.
1) SKB_DROP_REASON_BRIDGE_FWD_NO_BACKUP_PORT: failed to get a backup
port link when the destination port is down.
2) SKB_DROP_REASON_BRIDGE_FWD_SAME_PORT: destination port is the same
with originating port when forwarding by a bridge.
3) SKB_DROP_REASON_BRIDGE_NON_FORWARDING_STATE: the bridge's state is
not forwarding.
4) SKB_DROP_REASON_BRIDGE_NOT_ALLOWED_EGRESS: the packet is not allowed
to go out through the port due to vlan filtering.
5) SKB_DROP_REASON_BRIDGE_SWDEV_NOT_ALLOWED_EGRESS: the packet is not
allowed to go out through the port which is offloaded by a hardware
switchdev, checked by nbp_switchdev_allowed_egress().
6) SKB_DROP_REASON_BRIDGE_BOTH_PORT_ISOLATED: both source port and dest
port are in BR_ISOLATED state when bridge forwarding.
Signed-off-by: xu xin <xu.xin16@xxxxxxxxxx>
Reviewed-by: Zhang Yunkai <zhang.yunkai@xxxxxxxxxx>
Reviewed-by: Yang Yang <yang.yang19@xxxxxxxxxx>
Cc: Xuexin Jiang <jiang.xuexin@xxxxxxxxxx>
---
include/net/dropreason.h | 33 ++++++++++++++++++++++++++++++++
net/bridge/br_forward.c | 49 +++++++++++++++++++++++++++++++++++++-----------
2 files changed, 71 insertions(+), 11 deletions(-)
diff --git a/include/net/dropreason.h b/include/net/dropreason.h
index c0a3ea806cd5..888039fd01c9 100644
--- a/include/net/dropreason.h
+++ b/include/net/dropreason.h
@@ -78,6 +78,12 @@
FN(IPV6_NDISC_BAD_CODE) \
FN(IPV6_NDISC_BAD_OPTIONS) \
FN(IPV6_NDISC_NS_OTHERHOST) \
+ FN(BRIDGE_FWD_NO_BACKUP_PORT) \
+ FN(BRIDGE_FWD_SAME_PORT) \
+ FN(BRIDGE_NON_FORWARDING_STATE) \
+ FN(BRIDGE_NOT_ALLOWED_EGRESS) \
+ FN(BRIDGE_SWDEV_NOT_ALLOWED_EGRESS) \
+ FN(BRIDGE_BOTH_PORT_ISOLATED) \
FNe(MAX)
/**
@@ -338,6 +344,33 @@ enum skb_drop_reason {
* for another host.
*/
SKB_DROP_REASON_IPV6_NDISC_NS_OTHERHOST,
+ /** @SKB_DROP_REASON_BRIDGE_FWD_NO_BACKUP_PORT: failed to get a backup
+ * port link when the destination port is down.
+ */
+ SKB_DROP_REASON_BRIDGE_FWD_NO_BACKUP_PORT,
+ /** @SKB_DROP_REASON_BRIDGE_FWD_SAME_PORT: destination port is the same
+ * with originating port when forwarding by a bridge.
+ */
+ SKB_DROP_REASON_BRIDGE_FWD_SAME_PORT,
+ /** @SKB_DROP_REASON_BRIDGE_NON_FORWARDING_STATE: the bridge's state is
+ * not forwarding.
+ */
+ SKB_DROP_REASON_BRIDGE_NON_FORWARDING_STATE,
+ /** @SKB_DROP_REASON_BRIDGE_NOT_ALLOWED_EGRESS: the packet is not allowed
+ * to go out through the port due to vlan filtering.
+ */
+ SKB_DROP_REASON_BRIDGE_NOT_ALLOWED_EGRESS,
+ /** @SKB_DROP_REASON_BRIDGE_SWDEV_NOT_ALLOWED_EGRESS: the packet is not
+ * allowed to go out through the port which is offloaded by a hardware
+ * switchdev, checked by nbp_switchdev_allowed_egress(). E.g, the source
+ * switchdev is the same with the switchdev by which the dest port is
+ * offloaded.
+ */
+ SKB_DROP_REASON_BRIDGE_SWDEV_NOT_ALLOWED_EGRESS,
+ /** @SKB_DROP_REASON_BRIDGE_BOTH_PORT_ISOLATED: both source port and dest
+ * port are in BR_ISOLATED state when bridge forwarding.
+ */
+ SKB_DROP_REASON_BRIDGE_BOTH_PORT_ISOLATED,
/**
* @SKB_DROP_REASON_MAX: the maximum of drop reason, which shouldn't be
* used as a real 'reason'
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 02bb620d3b8d..7ebdf9937125 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -18,16 +18,39 @@
#include "br_private.h"
/* Don't forward packets to originating port or forwarding disabled */
-static inline int should_deliver(const struct net_bridge_port *p,
- const struct sk_buff *skb)
+static inline bool should_deliver(const struct net_bridge_port *p, const struct sk_buff *skb,
+ enum skb_drop_reason *need_reason)
{
struct net_bridge_vlan_group *vg;
+ enum skb_drop_reason reason;
vg = nbp_vlan_group_rcu(p);
- return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
- p->state == BR_STATE_FORWARDING && br_allowed_egress(vg, skb) &&
- nbp_switchdev_allowed_egress(p, skb) &&
- !br_skb_isolated(p, skb);
+ if (!(p->flags & BR_HAIRPIN_MODE) && skb->dev == p->dev) {
+ reason = SKB_DROP_REASON_BRIDGE_FWD_SAME_PORT;
+ goto undeliverable;
+ }
+ if (p->state != BR_STATE_FORWARDING) {
+ reason = SKB_DROP_REASON_BRIDGE_NON_FORWARDING_STATE;
+ goto undeliverable;
+ }
+ if (!br_allowed_egress(vg, skb)) {
+ reason = SKB_DROP_REASON_BRIDGE_NOT_ALLOWED_EGRESS;
+ goto undeliverable;
+ }
+ if (!nbp_switchdev_allowed_egress(p, skb)) {
+ reason = SKB_DROP_REASON_BRIDGE_SWDEV_NOT_ALLOWED_EGRESS;
+ goto undeliverable;
+ }
+ if (br_skb_isolated(p, skb)) {
+ reason = SKB_DROP_REASON_BRIDGE_BOTH_PORT_ISOLATED;
+ goto undeliverable;
+ }
+ return true;
+
+undeliverable:
+ if (need_reason)
+ *need_reason = reason;
+ return false;
}
int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
@@ -144,6 +167,8 @@ static int deliver_clone(const struct net_bridge_port *prev,
void br_forward(const struct net_bridge_port *to,
struct sk_buff *skb, bool local_rcv, bool local_orig)
{
+ enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
+
if (unlikely(!to))
goto out;
@@ -152,12 +177,14 @@ void br_forward(const struct net_bridge_port *to,
struct net_bridge_port *backup_port;
backup_port = rcu_dereference(to->backup_port);
- if (unlikely(!backup_port))
+ if (unlikely(!backup_port)) {
+ reason = SKB_DROP_REASON_BRIDGE_FWD_NO_BACKUP_PORT;
goto out;
+ }
to = backup_port;
}
- if (should_deliver(to, skb)) {
+ if (should_deliver(to, skb, &reason)) {
if (local_rcv)
deliver_clone(to, skb, local_orig);
else
@@ -167,7 +194,7 @@ void br_forward(const struct net_bridge_port *to,
out:
if (!local_rcv)
- kfree_skb(skb);
+ kfree_skb_reason(skb, reason);
}
EXPORT_SYMBOL_GPL(br_forward);
@@ -178,7 +205,7 @@ static struct net_bridge_port *maybe_deliver(
u8 igmp_type = br_multicast_igmp_type(skb);
int err;
- if (!should_deliver(p, skb))
+ if (!should_deliver(p, skb, NULL))
return prev;
nbp_switchdev_frame_mark_tx_fwd_to_hwdom(p, skb);
@@ -254,7 +281,7 @@ static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
const unsigned char *src = eth_hdr(skb)->h_source;
- if (!should_deliver(p, skb))
+ if (!should_deliver(p, skb, NULL))
return;
/* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
--
2.15.2