[RFC PATCH v7 12/19] Add a hook to intercept external buffers from NIC driver.

xiaohui.xin
2010-06-05T10:14:51Z

From: Xin Xiaohui <xiaohui.xin@intel.com>

The hook is called in netif_receive_skb().
Signed-off-by: Xin Xiaohui <xiaohui.xin@intel.com>
Signed-off-by: Zhao Yu <yzhao81new@gmail.com>
Reviewed-by: Jeff Dike <jdike@linux.intel.com>
---
net/core/dev.c | 35 +++++++++++++++++++++++++++++++++++
1 files changed, 35 insertions(+), 0 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 37b389a..dc2f225 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2548,6 +2548,37 @@ err:
EXPORT_SYMBOL(netdev_mp_port_prep);
#endif

+#if defined(CONFIG_MEDIATE_PASSTHRU) || defined(CONFIG_MEDIATE_PASSTHRU_MODULE)
+/* Add a hook to intercept mediate passthru(zero-copy) packets,
+ * and insert it to the socket queue owned by mp_port specially.
+ */
+static inline struct sk_buff *handle_mpassthru(struct sk_buff *skb,
+ struct packet_type **pt_prev,
+ int *ret,
+ struct net_device *orig_dev)
+{
+ struct mpassthru_port *mp_port = NULL;
+ struct sock *sk = NULL;
+
+ if (!dev_is_mpassthru(skb->dev))
+ return skb;
+ mp_port = skb->dev->mp_port;
+
+ if (*pt_prev) {
+ *ret = deliver_skb(skb, *pt_prev, orig_dev);
+ *pt_prev = NULL;
+ }
+
+ sk = mp_port->sock->sk;
+ skb_queue_tail(&sk->sk_receive_queue, skb);
+ sk->sk_state_change(sk);
+
+ return NULL;
+}
+#else
+#define handle_mpassthru(skb, pt_prev, ret, orig_dev) (skb)
+#endif
+
/**
* netif_receive_skb - process receive buffer from network
* @skb: buffer to process
@@ -2629,6 +2660,10 @@ int netif_receive_skb(struct sk_buff *skb)
ncls:
#endif

+ /* To intercept mediate passthru(zero-copy) packets here */
+ skb = handle_mpassthru(skb, &pt_prev, &ret, orig_dev);
+ if (!skb)
+ goto out;
skb = handle_bridge(skb, &pt_prev, &ret, orig_dev);
if (!skb)
goto out;
--
1.5.4.4