[1/2] batman-adv: Add wrapper for ARP reply creation
Commit Message
Removing duplicate code.
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
Changes in RFC -> non-RFC:
* Added kerneldoc
* Added Signed-off-by
net/batman-adv/distributed-arp-table.c | 61 ++++++++++++++++++++++------------
1 file changed, 40 insertions(+), 21 deletions(-)
Comments
On Saturday 02 July 2016 06:09:50 Linus Lüssing wrote:
[...]
> +
> + if (vid & BATADV_VLAN_HAS_TAG)
> + skb = vlan_insert_tag(skb, htons(ETH_P_8021Q),
> + vid & VLAN_VID_MASK);
> +
> + skb_reset_mac_header(skb);
> +
> + return skb;
> +}
vlan_insert_tag can return NULL when an error happens. Thus simply doing
a skb_reset_mac_header on it without checking skb's value for !NULL is a
bad idea.
But you can simply move the skb_reset_mac_header (when it is really
necessary) in front of the 'if (vid & BATADV_VLAN_HAS_TAG)'.
Doing it in front would result in (written as absolute values - in
reality mac_header is an offset):
skb->mac_header = skb->data
skb->data -= VLAN_HLEN
skb->mac_header -= VLAN_HLEN
Writing it after the vlan_insert_tag would result in:
skb->data -= VLAN_HLEN
skb->mac_header -= VLAN_HLEN
skb->mac_header = skb->data
Both calculations should result in skb->mac_header == skb->data
Kind regards,
Sven
@@ -948,6 +948,41 @@ static unsigned short batadv_dat_get_vid(struct sk_buff *skb, int *hdr_size)
}
/**
+ * batadv_dat_arp_create_reply - create an ARP Reply
+ * @bat_priv: the bat priv with all the soft interface information
+ * @ip_src: ARP sender IP
+ * @ip_dst: ARP target IP
+ * @hw_src: Ethernet source and ARP sender MAC
+ * @hw_dst: Ethernet destination and ARP target MAC
+ * @vid: VLAN identifier (optional, set to zero otherwise)
+ *
+ * Creates an ARP Reply from the given values, optionally encapsulated in a
+ * VLAN header.
+ *
+ * Return: An skb containing an ARP Reply.
+ */
+static struct sk_buff *
+batadv_dat_arp_create_reply(struct batadv_priv *bat_priv, __be32 ip_src,
+ __be32 ip_dst, u8 *hw_src, u8 *hw_dst,
+ unsigned short vid)
+{
+ struct sk_buff *skb;
+
+ skb = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_dst, bat_priv->soft_iface,
+ ip_src, hw_dst, hw_src, hw_dst);
+ if (!skb)
+ return NULL;
+
+ if (vid & BATADV_VLAN_HAS_TAG)
+ skb = vlan_insert_tag(skb, htons(ETH_P_8021Q),
+ vid & VLAN_VID_MASK);
+
+ skb_reset_mac_header(skb);
+
+ return skb;
+}
+
+/**
* batadv_dat_snoop_outgoing_arp_request - snoop the ARP request and try to
* answer using DAT
* @bat_priv: the bat priv with all the soft interface information
@@ -1005,17 +1040,12 @@ bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
goto out;
}
- skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
- bat_priv->soft_iface, ip_dst, hw_src,
- dat_entry->mac_addr, hw_src);
+ skb_new = batadv_dat_arp_create_reply(bat_priv, ip_dst, ip_src,
+ dat_entry->mac_addr,
+ hw_src, vid);
if (!skb_new)
goto out;
- if (vid & BATADV_VLAN_HAS_TAG)
- skb_new = vlan_insert_tag(skb_new, htons(ETH_P_8021Q),
- vid & VLAN_VID_MASK);
-
- skb_reset_mac_header(skb_new);
skb_new->protocol = eth_type_trans(skb_new,
bat_priv->soft_iface);
bat_priv->stats.rx_packets++;
@@ -1079,22 +1109,11 @@ bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
if (!dat_entry)
goto out;
- skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
- bat_priv->soft_iface, ip_dst, hw_src,
- dat_entry->mac_addr, hw_src);
-
+ skb_new = batadv_dat_arp_create_reply(bat_priv, ip_dst, ip_src,
+ dat_entry->mac_addr, hw_src, vid);
if (!skb_new)
goto out;
- /* the rest of the TX path assumes that the mac_header offset pointing
- * to the inner Ethernet header has been set, therefore reset it now.
- */
- skb_reset_mac_header(skb_new);
-
- if (vid & BATADV_VLAN_HAS_TAG)
- skb_new = vlan_insert_tag(skb_new, htons(ETH_P_8021Q),
- vid & VLAN_VID_MASK);
-
/* To preserve backwards compatibility, the node has choose the outgoing
* format based on the incoming request packet type. The assumption is
* that a node not using the 4addr packet format doesn't support it.