datapath: Add support for RHEL-7 / CentOS-7 kernel.

This patch mostly is related to tunnel API where RHEL 7
kernel API are not in-sync with newer linux kernel API. So
extra checks are required to check for parameters of API.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jiri Benc <jbenc@redhat.com>

acinclude.m4

@@ -284,6 +284,7 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
 
   OVS_GREP_IFELSE([$KSRC/include/linux/err.h], [ERR_CAST])
   OVS_GREP_IFELSE([$KSRC/include/linux/err.h], [IS_ERR_OR_NULL])
+  OVS_GREP_IFELSE([$KSRC/include/linux/hash.h], [fast_hash_ops])
 
   OVS_GREP_IFELSE([$KSRC/include/linux/etherdevice.h], [eth_hw_addr_random])
   OVS_GREP_IFELSE([$KSRC/include/linux/etherdevice.h], [ether_addr_copy])
@@ -341,6 +342,8 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
   OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [skb_orphan_frags])
   OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [skb_get_hash])
   OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [skb_clear_hash])
+  OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [int.skb_zerocopy(],
+                  [OVS_DEFINE([HAVE_SKB_ZEROCOPY])])
   OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [l4_rxhash])
 
   OVS_GREP_IFELSE([$KSRC/include/linux/types.h], [bool],
@@ -356,7 +359,11 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
   OVS_GREP_IFELSE([$KSRC/include/net/genetlink.h], [genl_has_listeners])
   OVS_GREP_IFELSE([$KSRC/include/net/genetlink.h], [mcgrp_offset])
   OVS_GREP_IFELSE([$KSRC/include/net/genetlink.h], [parallel_ops])
+  OVS_GREP_IFELSE([$KSRC/include/net/genetlink.h], [genlmsg_new_unicast])
   OVS_GREP_IFELSE([$KSRC/include/net/gre.h], [gre_cisco_register])
+  OVS_GREP_IFELSE([$KSRC/include/net/gre.h], [gre_handle_offloads])
+  OVS_GREP_IFELSE([$KSRC/include/net/ip_tunnels.h], [iptunnel_xmit.*net],
+                  [OVS_DEFINE([HAVE_IPTUNNEL_XMIT_NET])])
   OVS_GREP_IFELSE([$KSRC/include/net/netlink.h], [nla_get_be16])
   OVS_GREP_IFELSE([$KSRC/include/net/netlink.h], [nla_put_be16])
   OVS_GREP_IFELSE([$KSRC/include/net/netlink.h], [nla_put_be32])

datapath/datapath.c

@@ -408,7 +408,7 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
 	struct sk_buff *user_skb = NULL; /* to be queued to userspace */
 	struct nlattr *nla;
 	struct genl_info info = {
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,14,0)
+#ifdef HAVE_GENLMSG_NEW_UNICAST
 		.dst_sk = ovs_dp_get_net(dp)->genl_sock,
 #endif
 		.snd_portid = upcall_info->portid,

datapath/linux/compat/gre.c

@@ -268,6 +268,8 @@ int gre_cisco_unregister(struct gre_cisco_protocol *proto)
 
 #endif /* !HAVE_GRE_CISCO_REGISTER */
 
+#ifndef GRE_USE_KERNEL_GRE_HANDLE_OFFLOADS
+
 /* GRE TX side. */
 static void gre_csum_fix(struct sk_buff *skb)
 {
@@ -343,6 +345,7 @@ void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 		}
 	}
 }
+#endif
 
 #endif /* CONFIG_NET_IPGRE_DEMUX */
 

datapath/linux/compat/include/linux/hash.h

@@ -2,11 +2,10 @@
 #define _LINUX_HASH_WRAPPER_H
 
 #include_next <linux/hash.h>
-
-#include <linux/version.h>
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,14,0)
 #include <asm/hash.h>
 
+#ifndef HAVE_FAST_HASH_OPS
+
 struct fast_hash_ops {
 	u32 (*hash)(const void *data, u32 len, u32 seed);
 	u32 (*hash2)(const u32 *data, u32 len, u32 seed);
@@ -40,6 +39,6 @@ extern u32 arch_fast_hash(const void *data, u32 len, u32 seed);
  *	Returns 32bit hash.
  */
 extern u32 arch_fast_hash2(const u32 *data, u32 len, u32 seed);
-#endif /* < 3.14 */
+#endif /* !HASH_FAST_HASH_OPS */
 
 #endif /* _LINUX_HASH_WRAPPER_H */

datapath/linux/compat/include/linux/skbuff.h

@@ -288,6 +288,10 @@ static inline void skb_tx_error(struct sk_buff *skb)
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3,14,0)
 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
+#endif
+
+#ifndef HAVE_SKB_ZEROCOPY
+#define skb_zerocopy rpl_skb_zerocopy
 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len,
 		  int hlen);
 #endif

datapath/linux/compat/include/net/genetlink.h

@@ -96,7 +96,7 @@ static inline int rpl_genl_register_family(struct genl_family *family)
 
 #endif
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,14,0)
+#ifndef HAVE_GENLMSG_NEW_UNICAST
 static inline struct sk_buff *genlmsg_new_unicast(size_t payload,
 						  struct genl_info *info,
 						  gfp_t flags)

datapath/linux/compat/include/net/gre.h

@@ -81,7 +81,7 @@ static inline __be16 tnl_flags_to_gre_flags(__be16 tflags)
 #endif /* LINUX_VERSION_CODE < KERNEL_VERSION(3,10,0) */
 #endif /* HAVE_GRE_CISCO_REGISTER */
 
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,12,0)
+#ifndef GRE_USE_KERNEL_GRE_HANDLE_OFFLOADS
 
 #define gre_build_header rpl_gre_build_header
 void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi,

datapath/linux/compat/include/net/ip_tunnels.h

@@ -2,7 +2,15 @@
 #define __NET_IP_TUNNELS_WRAPPER_H 1
 
 #include <linux/version.h>
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,12,0)
+#if defined(HAVE_GRE_HANDLE_OFFLOADS) && \
+     LINUX_VERSION_CODE >= KERNEL_VERSION(3,10,0)
+/* RHEL6 and RHEL7 both has backported tunnel API but RHEL6 has
+ * older version, so avoid using RHEL6 backports.
+ */
+#define GRE_USE_KERNEL_GRE_HANDLE_OFFLOADS
+#endif
+
+#ifdef GRE_USE_KERNEL_GRE_HANDLE_OFFLOADS
 #include_next <net/ip_tunnels.h>
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3,15,0)
@@ -11,7 +19,11 @@ static inline int rpl_iptunnel_xmit(struct sock *sk, struct rtable *rt,
 				    __be32 dst, __u8 proto, __u8 tos,
 				    __u8 ttl, __be16 df, bool xnet)
 {
+#ifdef HAVE_IPTUNNEL_XMIT_NET
+	return iptunnel_xmit(NULL, rt, skb, src, dst, proto, tos, ttl, df);
+#else
 	return iptunnel_xmit(rt, skb, src, dst, proto, tos, ttl, df, xnet);
+#endif
 }
 #define iptunnel_xmit rpl_iptunnel_xmit
 #endif

datapath/linux/compat/include/net/vxlan.h

@@ -4,9 +4,10 @@
 #include <linux/skbuff.h>
 #include <linux/netdevice.h>
 #include <linux/udp.h>
+#include <net/gre.h>
 
 #include <linux/version.h>
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,12,0)
+#ifdef GRE_USE_KERNEL_GRE_HANDLE_OFFLOADS
 #include_next <net/vxlan.h>
 
 static inline int rpl_vxlan_xmit_skb(struct vxlan_sock *vs,
@@ -23,8 +24,14 @@ static inline int rpl_vxlan_xmit_skb(struct vxlan_sock *vs,
 	return vxlan_xmit_skb(vs, rt, skb, src, dst, tos, ttl, df,
 			      src_port, dst_port, vni, false);
 #else
+#ifndef HAVE_IPTUNNEL_XMIT_NET
 	return vxlan_xmit_skb(vs, rt, skb, src, dst, tos, ttl, df,
 			      src_port, dst_port, vni);
+#else
+	return vxlan_xmit_skb(NULL, vs, rt, skb, src, dst, tos, ttl, df,
+			      src_port, dst_port, vni);
+#endif
+
 #endif
 }
 

datapath/linux/compat/ip_tunnels_core.c

@@ -16,8 +16,6 @@
  * 02110-1301, USA
  */
 
-#include <linux/version.h>
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,12,0)
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
@@ -37,6 +35,7 @@
 #include "compat.h"
 #include "gso.h"
 
+#ifndef GRE_USE_KERNEL_GRE_HANDLE_OFFLOADS
 int iptunnel_xmit(struct sock *sk, struct rtable *rt,
 		  struct sk_buff *skb,
 		  __be32 src, __be32 dst, __u8 proto,
@@ -117,4 +116,4 @@ int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto)
 	return 0;
 }
 
-#endif /* 3.12 */
+#endif

datapath/linux/compat/skbuff-openvswitch.c

@@ -49,6 +49,7 @@ skb_zerocopy_headlen(const struct sk_buff *from)
 	return hlen;
 }
 
+#ifndef HAVE_SKB_ZEROCOPY
 /**
  *	skb_zerocopy - Zero copy skb to skb
  *	@to: destination buffer
@@ -122,3 +123,4 @@ skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
 	return 0;
 }
 #endif
+#endif

datapath/linux/compat/vxlan.c

@@ -19,7 +19,6 @@
  */
 
 #include <linux/version.h>
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,12,0)
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
@@ -43,6 +42,7 @@
 #include <net/arp.h>
 #include <net/ndisc.h>
 #include <net/ip.h>
+#include <net/gre.h>
 #include <net/ip_tunnels.h>
 #include <net/icmp.h>
 #include <net/udp.h>
@@ -58,6 +58,7 @@
 #include "datapath.h"
 #include "gso.h"
 #include "vlan.h"
+#ifndef GRE_USE_KERNEL_GRE_HANDLE_OFFLOADS
 
 #define VXLAN_HLEN (sizeof(struct udphdr) + sizeof(struct vxlanhdr))