[NET]: Detect hardware rx checksum faults correctly
Here is the patch that introduces the generic skb_checksum_complete
which also checks for hardware RX checksum faults. If that happens,
it'll call netdev_rx_csum_fault which currently prints out a stack
trace with the device name. In future it can turn off RX checksum.
I've converted every spot under net/ that does RX checksum checks to
use skb_checksum_complete or __skb_checksum_complete with the
exceptions of:
* Those places where checksums are done bit by bit. These will call
netdev_rx_csum_fault directly.
* The following have not been completely checked/converted:
ipmr
ip_vs
netfilter
dccp
This patch is based on patches and suggestions from Stephen Hemminger
and David S. Miller.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c6efce4..936f8b7 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -927,6 +927,13 @@
extern int weight_p;
extern int netdev_set_master(struct net_device *dev, struct net_device *master);
extern int skb_checksum_help(struct sk_buff *skb, int inward);
+#ifdef CONFIG_BUG
+extern void netdev_rx_csum_fault(struct net_device *dev);
+#else
+static inline void netdev_rx_csum_fault(struct net_device *dev)
+{
+}
+#endif
/* rx skb timestamps */
extern void net_enable_timestamp(void);
extern void net_disable_timestamp(void);
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 8301023..0a8ea8b 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1236,8 +1236,7 @@
extern int skb_copy_datagram_iovec(const struct sk_buff *from,
int offset, struct iovec *to,
int size);
-extern int skb_copy_and_csum_datagram_iovec(const
- struct sk_buff *skb,
+extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
int hlen,
struct iovec *iov);
extern void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
@@ -1305,6 +1304,30 @@
extern void __net_timestamp(struct sk_buff *skb);
+extern unsigned int __skb_checksum_complete(struct sk_buff *skb);
+
+/**
+ * skb_checksum_complete - Calculate checksum of an entire packet
+ * @skb: packet to process
+ *
+ * This function calculates the checksum over the entire packet plus
+ * the value of skb->csum. The latter can be used to supply the
+ * checksum of a pseudo header as used by TCP/UDP. It returns the
+ * checksum.
+ *
+ * For protocols that contain complete checksums such as ICMP/TCP/UDP,
+ * this function can be used to verify that checksum on received
+ * packets. In that case the function should return zero if the
+ * checksum is correct. In particular, this function will return zero
+ * if skb->ip_summed is CHECKSUM_UNNECESSARY which indicates that the
+ * hardware has already verified the correctness of the checksum.
+ */
+static inline unsigned int skb_checksum_complete(struct sk_buff *skb)
+{
+ return skb->ip_summed != CHECKSUM_UNNECESSARY &&
+ __skb_checksum_complete(skb);
+}
+
#ifdef CONFIG_NETFILTER
static inline void nf_conntrack_put(struct nf_conntrack *nfct)
{
diff --git a/include/net/tcp.h b/include/net/tcp.h
index c24339c..96cc3b4 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -27,6 +27,7 @@
#include <linux/slab.h>
#include <linux/cache.h>
#include <linux/percpu.h>
+#include <linux/skbuff.h>
#include <net/inet_connection_sock.h>
#include <net/inet_timewait_sock.h>
@@ -852,7 +853,7 @@
static __inline__ int __tcp_checksum_complete(struct sk_buff *skb)
{
- return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
+ return __skb_checksum_complete(skb);
}
static __inline__ int tcp_checksum_complete(struct sk_buff *skb)