[ovs-dev] [PATCH v2] datapath: gre: Reset fix_segment pointer.

[Pravin B Shelar]

For kernel version 3.12 to 3.18, GRE uses compat code to
transmit packets which used fix_segment to segment packets.
but ovs_gso_cb->fix_segment is not initialized for GRE tunnels.
Following patches fixes it by resetting fix_segment.

Signed-off-by: Pravin B Shelar <pshelar at nicira.com>
---
Fixed for kernel 3.12 and newer.
---
 datapath/linux/compat/gre.c             |   50 ++++++++++++++++++------------
 datapath/linux/compat/include/net/gre.h |   18 ++---------
 2 files changed, 33 insertions(+), 35 deletions(-)

diff --git a/datapath/linux/compat/gre.c b/datapath/linux/compat/gre.c
index e2a7591..fe81380 100644
--- a/datapath/linux/compat/gre.c
+++ b/datapath/linux/compat/gre.c
@@ -17,11 +17,7 @@
  */
 
 #include <linux/version.h>
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,12,0)
-
 #include <linux/kconfig.h>
-#if IS_ENABLED(CONFIG_NET_IPGRE_DEMUX)
-
 #include <linux/module.h>
 #include <linux/if.h>
 #include <linux/if_tunnel.h>
@@ -42,6 +38,10 @@
 
 #include "gso.h"
 
+#if IS_ENABLED(CONFIG_NET_IPGRE_DEMUX)
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3,12,0)
+
 #ifndef HAVE_GRE_CISCO_REGISTER
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,37)
@@ -287,20 +287,6 @@ static void gre_csum_fix(struct sk_buff *skb)
 						     skb->len - gre_offset, 0));
 }
 
-struct sk_buff *rpl_gre_handle_offloads(struct sk_buff *skb, bool gre_csum)
-{
-	int type = gre_csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE;
-	gso_fix_segment_t fix_segment;
-
-	if (gre_csum)
-		fix_segment = gre_csum_fix;
-	else
-		fix_segment = gre_nop_fix;
-
-	return ovs_iptunnel_handle_offloads(skb, gre_csum, type, fix_segment);
-}
-EXPORT_SYMBOL_GPL(rpl_gre_handle_offloads);
-
 static bool is_gre_gso(struct sk_buff *skb)
 {
 	return skb_is_gso(skb);
@@ -339,6 +325,30 @@ void rpl_gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 }
 EXPORT_SYMBOL_GPL(rpl_gre_build_header);
 
-#endif /* CONFIG_NET_IPGRE_DEMUX */
+struct sk_buff *rpl_gre_handle_offloads(struct sk_buff *skb, bool gre_csum)
+{
+	int type = gre_csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE;
+	gso_fix_segment_t fix_segment;
+
+	if (gre_csum)
+		fix_segment = gre_csum_fix;
+	else
+		fix_segment = gre_nop_fix;
 
-#endif /* 3.12 */
+	return ovs_iptunnel_handle_offloads(skb, gre_csum, type, fix_segment);
+}
+#else
+struct sk_buff *rpl_gre_handle_offloads(struct sk_buff *skb, bool gre_csum)
+{
+	if (skb_is_gso(skb) && skb_is_encapsulated(skb)) {
+		kfree_skb(skb);
+		return ERR_PTR(-ENOSYS);
+	}
+	skb_clear_ovs_gso_cb(skb);
+#undef gre_handle_offloads
+	return gre_handle_offloads(skb, gre_csum);
+}
+#endif
+EXPORT_SYMBOL_GPL(rpl_gre_handle_offloads);
+
+#endif /* CONFIG_NET_IPGRE_DEMUX */
diff --git a/datapath/linux/compat/include/net/gre.h b/datapath/linux/compat/include/net/gre.h
index f572ac9..6e0df0f 100644
--- a/datapath/linux/compat/include/net/gre.h
+++ b/datapath/linux/compat/include/net/gre.h
@@ -81,15 +81,15 @@ static inline __be16 tnl_flags_to_gre_flags(__be16 tflags)
 #endif /* LINUX_VERSION_CODE < KERNEL_VERSION(3,10,0) */
 #endif /* HAVE_GRE_CISCO_REGISTER */
 
+#define gre_handle_offloads rpl_gre_handle_offloads
+struct sk_buff *rpl_gre_handle_offloads(struct sk_buff *skb, bool gre_csum);
+
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3,12,0)
 
 #define gre_build_header rpl_gre_build_header
 void rpl_gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 		          int hdr_len);
 
-#define gre_handle_offloads rpl_gre_handle_offloads
-struct sk_buff *rpl_gre_handle_offloads(struct sk_buff *skb, bool gre_csum);
-
 #define ip_gre_calc_hlen rpl_ip_gre_calc_hlen
 static inline int ip_gre_calc_hlen(__be16 o_flags)
 {
@@ -103,18 +103,6 @@ static inline int ip_gre_calc_hlen(__be16 o_flags)
 		addend += 4;
 	return addend;
 }
-#else
-
-static inline struct sk_buff *rpl_gre_handle_offloads(struct sk_buff *skb,
-						  bool gre_csum)
-{
-	if (skb_is_gso(skb) && skb_is_encapsulated(skb)) {
-		kfree_skb(skb);
-		return ERR_PTR(-ENOSYS);
-	}
-	return gre_handle_offloads(skb, gre_csum);
-}
-#define gre_handle_offloads rpl_gre_handle_offloads
 #endif
 
 #endif
-- 
1.7.1