vrf: handle CONFIG_IPV6 not set for vrf_add_mac_header_if_unset()

The vrf_add_mac_header_if_unset() is defined within a conditional
compilation block which depends on the CONFIG_IPV6 macro.
However, the vrf_add_mac_header_if_unset() needs to be called also by IPv4
related code and when the CONFIG_IPV6 is not set, this function is missing.
As a consequence, the build process stops reporting the error:

 ERROR: implicit declaration of function 'vrf_add_mac_header_if_unset'

The problem is solved by *only* moving functions
vrf_add_mac_header_if_unset() and vrf_prepare_mac_header() out of the
conditional block.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 0489390882202 ("vrf: add mac header for tunneled packets when sniffer is attached")
Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20201208175210.8906-1-andrea.mayer@uniroma2.it
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 259d5cb..571bd03 100644 (file)
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -1237,6 +1237,61 @@ static struct sk_buff *vrf_rcv_nfhook(u8 pf, unsigned int hook,
        return skb;
 }
 
+static int vrf_prepare_mac_header(struct sk_buff *skb,
+                                 struct net_device *vrf_dev, u16 proto)
+{
+       struct ethhdr *eth;
+       int err;
+
+       /* in general, we do not know if there is enough space in the head of
+        * the packet for hosting the mac header.
+        */
+       err = skb_cow_head(skb, LL_RESERVED_SPACE(vrf_dev));
+       if (unlikely(err))
+               /* no space in the skb head */
+               return -ENOBUFS;
+
+       __skb_push(skb, ETH_HLEN);
+       eth = (struct ethhdr *)skb->data;
+
+       skb_reset_mac_header(skb);
+
+       /* we set the ethernet destination and the source addresses to the
+        * address of the VRF device.
+        */
+       ether_addr_copy(eth->h_dest, vrf_dev->dev_addr);
+       ether_addr_copy(eth->h_source, vrf_dev->dev_addr);
+       eth->h_proto = htons(proto);
+
+       /* the destination address of the Ethernet frame corresponds to the
+        * address set on the VRF interface; therefore, the packet is intended
+        * to be processed locally.
+        */
+       skb->protocol = eth->h_proto;
+       skb->pkt_type = PACKET_HOST;
+
+       skb_postpush_rcsum(skb, skb->data, ETH_HLEN);
+
+       skb_pull_inline(skb, ETH_HLEN);
+
+       return 0;
+}
+
+/* prepare and add the mac header to the packet if it was not set previously.
+ * In this way, packet sniffers such as tcpdump can parse the packet correctly.
+ * If the mac header was already set, the original mac header is left
+ * untouched and the function returns immediately.
+ */
+static int vrf_add_mac_header_if_unset(struct sk_buff *skb,
+                                      struct net_device *vrf_dev,
+                                      u16 proto)
+{
+       if (skb_mac_header_was_set(skb))
+               return 0;
+
+       return vrf_prepare_mac_header(skb, vrf_dev, proto);
+}
+
 #if IS_ENABLED(CONFIG_IPV6)
 /* neighbor handling is done with actual device; do not want
  * to flip skb->dev for those ndisc packets. This really fails
@@ -1310,61 +1365,6 @@ static void vrf_ip6_input_dst(struct sk_buff *skb, struct net_device *vrf_dev,
        skb_dst_set(skb, &rt6->dst);
 }
 
-static int vrf_prepare_mac_header(struct sk_buff *skb,
-                                 struct net_device *vrf_dev, u16 proto)
-{
-       struct ethhdr *eth;
-       int err;
-
-       /* in general, we do not know if there is enough space in the head of
-        * the packet for hosting the mac header.
-        */
-       err = skb_cow_head(skb, LL_RESERVED_SPACE(vrf_dev));
-       if (unlikely(err))
-               /* no space in the skb head */
-               return -ENOBUFS;
-
-       __skb_push(skb, ETH_HLEN);
-       eth = (struct ethhdr *)skb->data;
-
-       skb_reset_mac_header(skb);
-
-       /* we set the ethernet destination and the source addresses to the
-        * address of the VRF device.
-        */
-       ether_addr_copy(eth->h_dest, vrf_dev->dev_addr);
-       ether_addr_copy(eth->h_source, vrf_dev->dev_addr);
-       eth->h_proto = htons(proto);
-
-       /* the destination address of the Ethernet frame corresponds to the
-        * address set on the VRF interface; therefore, the packet is intended
-        * to be processed locally.
-        */
-       skb->protocol = eth->h_proto;
-       skb->pkt_type = PACKET_HOST;
-
-       skb_postpush_rcsum(skb, skb->data, ETH_HLEN);
-
-       skb_pull_inline(skb, ETH_HLEN);
-
-       return 0;
-}
-
-/* prepare and add the mac header to the packet if it was not set previously.
- * In this way, packet sniffers such as tcpdump can parse the packet correctly.
- * If the mac header was already set, the original mac header is left
- * untouched and the function returns immediately.
- */
-static int vrf_add_mac_header_if_unset(struct sk_buff *skb,
-                                      struct net_device *vrf_dev,
-                                      u16 proto)
-{
-       if (skb_mac_header_was_set(skb))
-               return 0;
-
-       return vrf_prepare_mac_header(skb, vrf_dev, proto);
-}
-
 static struct sk_buff *vrf_ip6_rcv(struct net_device *vrf_dev,
                                   struct sk_buff *skb)
 {