datapath: Add __vlan_insert_tag() compat helper if not available

Since older kernels do not have skb->vlan_proto, it is assumed that
kernels which don't provide their own __vlan_insert_tag() will also
not have skb->vlan_proto. The backwards compat function therefore
only supports ETH_P_8021Q as the protocol type.

Upstream: 15255a43 ("vlan: introduce __vlan_insert_tag helper which does not free skb")
Signed-off-by: Thomas Graf <tgraf@noironetworks.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>

diff --git a/acinclude.m4 b/acinclude.m4
index 05dc112..444141d 100644 (file)
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -377,6 +377,8 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
   OVS_GREP_IFELSE([$KSRC/include/linux/if_vlan.h], [ADD_ALL_VLANS_CMD],
                   [OVS_DEFINE([HAVE_VLAN_BUG_WORKAROUND])])
   OVS_GREP_IFELSE([$KSRC/include/linux/if_vlan.h], [vlan_insert_tag_set_proto])
+  OVS_GREP_IFELSE([$KSRC/include/linux/if_vlan.h], [__vlan_insert_tag])
+
 
   OVS_GREP_IFELSE([$KSRC/include/linux/u64_stats_sync.h], [u64_stats_fetch_begin_irq])
 

diff --git a/datapath/linux/compat/include/linux/if_vlan.h b/datapath/linux/compat/include/linux/if_vlan.h
index 616b3bf..28c4dae 100644 (file)
--- a/datapath/linux/compat/include/linux/if_vlan.h
+++ b/datapath/linux/compat/include/linux/if_vlan.h
@@ -106,4 +106,33 @@ static inline void vlan_set_encap_proto(struct sk_buff *skb, struct vlan_hdr *vh
                skb->protocol = htons(ETH_P_802_2);
 }
 #endif
+
+#ifndef HAVE___VLAN_INSERT_TAG
+/* Kernels which don't have __vlan_insert_tag() also don't have skb->vlan_proto
+ * so ignore the proto paramter.
+ */
+#define __vlan_insert_tag(skb, proto, tci) rpl_vlan_insert_tag(skb, tci)
+static inline int rpl_vlan_insert_tag(struct sk_buff *skb, u16 vlan_tci)
+{
+       struct vlan_ethhdr *veth;
+
+       if (skb_cow_head(skb, VLAN_HLEN) < 0)
+               return -ENOMEM;
+
+       veth = (struct vlan_ethhdr *)skb_push(skb, VLAN_HLEN);
+
+       /* Move the mac addresses to the beginning of the new header. */
+       memmove(skb->data, skb->data + VLAN_HLEN, 2 * ETH_ALEN);
+       skb->mac_header -= VLAN_HLEN;
+
+       /* first, the ethernet type */
+       veth->h_vlan_proto = htons(ETH_P_8021Q);
+
+       /* now, the TCI */
+       veth->h_vlan_TCI = htons(ETH_P_8021Q);
+
+       return 0;
+}
+#endif
+
 #endif /* linux/if_vlan.h wrapper */