[B.A.T.M.A.N.] [PATCHv2 2/7] batman-adv: speed up dat by snooping received ip traffic

Andreas Pape
2016-02-26T13:18:17Z

Speeding up dat address lookup is achieved by snooping all incoming ip
traffic. This especially increases the propability in bla setups that
a gateway into a common backbone network already has a fitting dat entry
to answer incoming ARP requests directly coming from the backbone
network thus further reducing ARP traffic in the mesh.

Signed-off-by: Andreas Pape <apape@phoenixcontact.com>
---
net/batman-adv/distributed-arp-table.c | 18 ++++++++++++++++++
net/batman-adv/distributed-arp-table.h | 9 ++++++++-
net/batman-adv/soft-interface.c | 22 +++++++++++++++++++++-
3 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
index a9152e7..0f899b9 100644
--- a/net/batman-adv/distributed-arp-table.c
+++ b/net/batman-adv/distributed-arp-table.c
@@ -362,6 +362,24 @@ out:
batadv_dat_entry_put(dat_entry);
}

+/**
+ * batadv_dat_entry_check - check and update a dat entry
+ * @bat_priv: the bat priv with all the soft interface information
+ * @ip: ipv4 to add/edit
+ * @mac_addr: mac address to assign to the given ipv4
+ * @vid: VLAN identifier
+ *
+ * checks additionally, if dat is enabled. can be called from other modules.
+ */
+void batadv_dat_entry_check(struct batadv_priv *bat_priv, __be32 ip,
+ u8 *mac_addr, unsigned short vid)
+{
+ if (!atomic_read(&bat_priv->distributed_arp_table))
+ return;
+
+ batadv_dat_entry_add(bat_priv, ip, mac_addr, vid);
+}
+
#ifdef CONFIG_BATMAN_ADV_DEBUG

/**
diff --git a/net/batman-adv/distributed-arp-table.h b/net/batman-adv/distributed-arp-table.h
index 813ecea..e1b4848 100644
--- a/net/batman-adv/distributed-arp-table.h
+++ b/net/batman-adv/distributed-arp-table.h
@@ -80,7 +80,8 @@ batadv_dat_init_own_addr(struct batadv_priv *bat_priv,
int batadv_dat_init(struct batadv_priv *bat_priv);
void batadv_dat_free(struct batadv_priv *bat_priv);
int batadv_dat_cache_seq_print_text(struct seq_file *seq, void *offset);
-
+void batadv_dat_entry_check(struct batadv_priv *bat_priv, __be32 ip,
+ u8 *mac_addr, unsigned short vid);
/**
* batadv_dat_inc_counter - increment the correct DAT packet counter
* @bat_priv: the bat priv with all the soft interface information
@@ -173,6 +174,12 @@ static inline void batadv_dat_inc_counter(struct batadv_priv *bat_priv,
{
}

+static inline
+void batadv_dat_entry_check(struct batadv_priv *bat_priv, __be32 ip,
+ u8 *mac_addr, unsigned short vid)
+{
+}
+
#endif /* CONFIG_BATMAN_ADV_DAT */

#endif /* _NET_BATMAN_ADV_DISTRIBUTED_ARP_TABLE_H_ */
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 0710379..f031781 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -28,6 +28,7 @@
#include <linux/fs.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
+#include <linux/ip.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kref.h>
@@ -390,6 +391,7 @@ void batadv_interface_rx(struct net_device *soft_iface,
__be16 ethertype = htons(ETH_P_BATMAN);
struct vlan_ethhdr *vhdr;
struct ethhdr *ethhdr;
+ struct iphdr *iphdr;
unsigned short vid;
bool is_bcast;

@@ -412,11 +414,29 @@ void batadv_interface_rx(struct net_device *soft_iface,
ethhdr = eth_hdr(skb);

switch (ntohs(ethhdr->h_proto)) {
+ case ETH_P_IP:
+ iphdr = (struct iphdr *)(skb->data + ETH_HLEN);
+ /* snoop incoming traffic for dat update using the source mac
+ * and source ip to speed up dat.
+ */
+ batadv_dat_entry_check(bat_priv, iphdr->saddr,
+ ethhdr->h_source, vid);
+ break;
case ETH_P_8021Q:
vhdr = (struct vlan_ethhdr *)skb->data;

- if (vhdr->h_vlan_encapsulated_proto != ethertype)
+ if (vhdr->h_vlan_encapsulated_proto != ethertype) {
+ /* snoop incoming traffic for dat update also for vlan
+ * tagged frames.
+ */
+ if (vhdr->h_vlan_encapsulated_proto == ETH_P_IP) {
+ iphdr = (struct iphdr *)(vhdr +
+ sizeof(struct vlan_ethhdr));
+ batadv_dat_entry_check(bat_priv, iphdr->saddr,
+ vhdr->h_source, vid);
+ }
break;
+ }

/* fall through */
case ETH_P_BATMAN:
--
1.7.0.4

..................................................................
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