[PATCH net-next v3 1/4] xfrm: bail early on slave pass over skb

From: Jarod Wilson
Date: Fri Jun 19 2020 - 10:32:37 EST


This is prep work for initial support of bonding hardware encryption
pass-through support. The bonding driver will fill in the slave_dev
pointer, and we use that to know not to skb_push() again on a given
skb that was already processed on the bond device.

CC: Jay Vosburgh <j.vosburgh@xxxxxxxxx>
CC: Veaceslav Falico <vfalico@xxxxxxxxx>
CC: Andy Gospodarek <andy@xxxxxxxxxxxxx>
CC: "David S. Miller" <davem@xxxxxxxxxxxxx>
CC: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
CC: Jakub Kicinski <kuba@xxxxxxxxxx>
CC: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
CC: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
CC: netdev@xxxxxxxxxxxxxxx
CC: intel-wired-lan@xxxxxxxxxxxxxxxx
Signed-off-by: Jarod Wilson <jarod@xxxxxxxxxx>
---
include/net/xfrm.h | 1 +
net/xfrm/xfrm_device.c | 34 +++++++++++++++++-----------------
2 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 094fe682f5d7..e20b2b27ec48 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -127,6 +127,7 @@ struct xfrm_state_walk {

struct xfrm_state_offload {
struct net_device *dev;
+ struct net_device *slave_dev;
unsigned long offload_handle;
unsigned int num_exthdrs;
u8 flags;
diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index f50d1f97cf8e..b8918fc5248b 100644
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -106,6 +106,7 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur
struct sk_buff *skb2, *nskb, *pskb = NULL;
netdev_features_t esp_features = features;
struct xfrm_offload *xo = xfrm_offload(skb);
+ struct net_device *dev = skb->dev;
struct sec_path *sp;

if (!xo)
@@ -119,6 +120,10 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur
if (xo->flags & XFRM_GRO || x->xso.flags & XFRM_OFFLOAD_INBOUND)
return skb;

+ /* This skb was already validated on the master dev */
+ if ((x->xso.dev != dev) && (x->xso.slave_dev == dev))
+ return skb;
+
local_irq_save(flags);
sd = this_cpu_ptr(&softnet_data);
err = !skb_queue_empty(&sd->xfrm_backlog);
@@ -129,25 +134,20 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur
return skb;
}

- if (skb_is_gso(skb)) {
- struct net_device *dev = skb->dev;
-
- if (unlikely(x->xso.dev != dev)) {
- struct sk_buff *segs;
+ if (skb_is_gso(skb) && unlikely(x->xso.dev != dev)) {
+ struct sk_buff *segs;

- /* Packet got rerouted, fixup features and segment it. */
- esp_features = esp_features & ~(NETIF_F_HW_ESP
- | NETIF_F_GSO_ESP);
+ /* Packet got rerouted, fixup features and segment it. */
+ esp_features = esp_features & ~(NETIF_F_HW_ESP | NETIF_F_GSO_ESP);

- segs = skb_gso_segment(skb, esp_features);
- if (IS_ERR(segs)) {
- kfree_skb(skb);
- atomic_long_inc(&dev->tx_dropped);
- return NULL;
- } else {
- consume_skb(skb);
- skb = segs;
- }
+ segs = skb_gso_segment(skb, esp_features);
+ if (IS_ERR(segs)) {
+ kfree_skb(skb);
+ atomic_long_inc(&dev->tx_dropped);
+ return NULL;
+ } else {
+ consume_skb(skb);
+ skb = segs;
}
}

--
2.20.1