datapath: more accurate checksumming in queue_userspace_packet()

Upstream commit: commit 7529390d08f07fbf9b0174c5a87600b5caa1a8e8 Author: Davide Caratti <[email protected]> Date: Thu May 18 15:44:42 2017 +0200 openvswitch: more accurate checksumming in queue_userspace_packet() if skb carries an SCTP packet and ip_summed is CHECKSUM_PARTIAL, it needs CRC32c in place of Internet Checksum: use skb_csum_hwoffload_help to avoid corrupting such packets while queueing them towards userspace. Signed-off-by: Davide Caratti <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Joe Stringer <[email protected]>
dkarhi · Jul 24, 2017 · a0c9fed · a0c9fed
1 parent ac8e3c6
commit a0c9fed
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Showing 3 changed files with 17 additions and 1 deletion.
diff --git a/acinclude.m4 b/acinclude.m4
@@ -538,6 +538,7 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
                   [OVS_DEFINE([HAVE_PCPU_SW_NETSTATS])])
   OVS_GREP_IFELSE([$KSRC/include/linux/netdevice.h], [netif_needs_gso.*net_device],
                   [OVS_DEFINE([HAVE_NETIF_NEEDS_GSO_NETDEV])])
+  OVS_GREP_IFELSE([$KSRC/include/linux/netdevice.h], [skb_csum_hwoffload_help])
   OVS_GREP_IFELSE([$KSRC/include/linux/netdevice.h], [udp_offload])
   OVS_GREP_IFELSE([$KSRC/include/linux/netdevice.h], [udp_offload.*uoff],
                   [OVS_DEFINE([HAVE_UDP_OFFLOAD_ARG_UOFF])])

diff --git a/datapath/datapath.c b/datapath/datapath.c
@@ -460,7 +460,7 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
 
 	/* Complete checksum if needed */
 	if (skb->ip_summed == CHECKSUM_PARTIAL &&
-	    (err = skb_checksum_help(skb)))
+	    (err = skb_csum_hwoffload_help(skb, 0)))
 		goto out;
 
 	/* Older versions of OVS user space enforce alignment of the last

diff --git a/datapath/linux/compat/include/linux/netdevice.h b/datapath/linux/compat/include/linux/netdevice.h
@@ -270,4 +270,19 @@ static inline void netdev_reset_rx_headroom(struct net_device *dev)
 #define IFF_NO_QUEUE 0
 #endif
 
+#ifndef HAVE_SKB_CSUM_HWOFFLOAD_HELP
+static inline int skb_csum_hwoffload_help(struct sk_buff *skb,
+					  const netdev_features_t features)
+{
+	/* It's less accurate to approximate to this for older kernels, but
+	 * it was sufficient for a long time. If you care about ensuring that
+	 * upstream commit 7529390d08f0 has the same effect on older kernels,
+	 * consider backporting the following commits:
+	 * b72b5bf6a8fc ("net: introduce skb_crc32c_csum_help")
+	 * 43c26a1a4593 ("net: more accurate checksumming in validate_xmit_skb()")
+	 */
+	return skb_checksum_help(skb);
+}
+#endif
+
 #endif /* __LINUX_NETDEVICE_WRAPPER_H */