[PATCH net-next] vrf: handle CONFIG_IPV6 not set for vrf_add_mac_header_if_unset()

From: Andrea Mayer
Date: Tue Dec 08 2020 - 12:55:50 EST


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@xxxxxxxxx>
Fixes: 0489390882202 ("vrf: add mac header for tunneled packets when sniffer is attached")
Signed-off-by: Andrea Mayer <andrea.mayer@xxxxxxxxxxx>
---
drivers/net/vrf.c | 110 +++++++++++++++++++++++-----------------------
1 file changed, 55 insertions(+), 55 deletions(-)

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 259d5cbacf2c..571bd03ebd81 100644
--- 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)
{
--
2.20.1