@@ -21,6 +21,8 @@
#include <linux/if_ether.h>
#include <linux/if_arp.h>
+/* needed to use arp_tbl */
+#include <net/arp.h>
#include "main.h"
#include "distributed-arp-table.h"
@@ -28,22 +30,14 @@
#include "originator.h"
#include "send.h"
#include "types.h"
+#include "translation-table.h"
#include "unicast.h"
static inline void bat_dbg_arp(struct bat_priv *bat_priv,
struct sk_buff *skb, uint16_t type) {
- char buf[30];
- const char *type_str[] = { "REQUEST", "REPLY", "RREQUEST", "RREPLY",
- "InREQUEST", "InREPLY", "NAK" };
-
- if (type >= 1 && type <= ARRAY_SIZE(type_str))
- scnprintf(buf, sizeof(buf), "%s", type_str[type - 1]);
- else
- scnprintf(buf, sizeof(buf), "UNKNOWN (%hu)", type);
-
- bat_dbg(DBG_ARP, bat_priv, "ARP message of type %s recognised "
- "[src: %pM-%pI4 dst: %pM-%pI4]\n", buf, ARP_HW_SRC(skb),
- &ARP_IP_SRC(skb), ARP_HW_DST(skb), &ARP_IP_DST(skb));
+ bat_dbg(DBG_ARP, bat_priv, "ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]\n",
+ ARP_HW_SRC(skb), &ARP_IP_SRC(skb), ARP_HW_DST(skb),
+ &ARP_IP_DST(skb));
}
/* Given a key, selects the candidates which the DHT message has to be sent to.
@@ -197,6 +191,31 @@ out:
return ret;
}
+/* Update the neighbour entry corresponding to the IP passed as parameter with
+ * the hw address hw. If the neighbour entry doesn't exists, then it will be
+ * created */
+static void arp_neigh_update(struct bat_priv *bat_priv, uint32_t ip,
+ uint8_t *hw)
+{
+ struct neighbour *n = NULL;
+ struct hard_iface *primary_if = primary_if_get_selected(bat_priv);
+ if (!primary_if)
+ goto out;
+
+ n = __neigh_lookup(&arp_tbl, &ip, primary_if->soft_iface, 1);
+ if (!n)
+ goto out;
+
+ bat_dbg(DBG_ARP, bat_priv, "Updating neighbour: %pI4 - %pM\n", &ip, hw);
+
+ neigh_update(n, hw, NUD_CONNECTED, NEIGH_UPDATE_F_OVERRIDE);
+out:
+ if (n && !IS_ERR(n))
+ neigh_release(n);
+ if (primary_if)
+ hardif_free_ref(primary_if);
+}
+
/* Returns arphdr->ar_op if the skb contains a valid ARP packet, otherwise
* returns 0 */
static uint16_t arp_get_type(struct bat_priv *bat_priv, struct sk_buff *skb)
@@ -232,7 +251,230 @@ static uint16_t arp_get_type(struct bat_priv *bat_priv, struct sk_buff *skb)
if (arphdr->ar_pln != 4)
goto out;
+ /* Check for bad reply/request. If the ARP message is not sane, DAT
+ * will simply ignore it */
+ if (ipv4_is_loopback(ARP_IP_SRC(skb)) ||
+ ipv4_is_multicast(ARP_IP_SRC(skb)) ||
+ ipv4_is_loopback(ARP_IP_DST(skb)) ||
+ ipv4_is_multicast(ARP_IP_DST(skb)))
+ goto out;
+
type = ntohs(arphdr->ar_op);
out:
return type;
}
+
+/* return true if the message has been sent to the dht candidates, false
+ * otherwise. In case of true the message has to be enqueued to permit the
+ * fallback */
+bool dat_snoop_outgoing_arp_request(struct bat_priv *bat_priv,
+ struct sk_buff *skb)
+{
+ uint16_t type = 0;
+ uint32_t ip_dst, ip_src;
+ uint8_t *hw_src;
+ bool ret = false;
+ struct neighbour *n = NULL;
+ struct hard_iface *primary_if = NULL;
+ struct sk_buff *skb_new;
+
+ type = arp_get_type(bat_priv, skb);
+ /* If we get an ARP_REQUEST we have to send the unicast message to the
+ * selected DHT candidates */
+ if (type != ARPOP_REQUEST)
+ goto out;
+
+ bat_dbg(DBG_ARP, bat_priv, "Parsing outgoing ARP REQUEST\n");
+ bat_dbg_arp(bat_priv, skb, type);
+
+ ip_src = ARP_IP_SRC(skb);
+ hw_src = ARP_HW_SRC(skb);
+ ip_dst = ARP_IP_DST(skb);
+
+ primary_if = primary_if_get_selected(bat_priv);
+ if (!primary_if)
+ goto out;
+
+ arp_neigh_update(bat_priv, ip_src, hw_src);
+
+ n = neigh_lookup(&arp_tbl, &ip_dst, primary_if->soft_iface);
+ /* check if it is a valid neigh entry */
+ if (n && (n->nud_state & NUD_CONNECTED)) {
+ skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
+ primary_if->soft_iface, ip_dst, hw_src,
+ n->ha, hw_src);
+ if (!skb_new)
+ goto out;
+
+ skb_reset_mac_header(skb_new);
+ skb_new->protocol = eth_type_trans(skb_new,
+ primary_if->soft_iface);
+ bat_priv->stats.rx_packets++;
+ bat_priv->stats.rx_bytes += skb->len + sizeof(struct ethhdr);
+ primary_if->soft_iface->last_rx = jiffies;
+
+ netif_rx(skb_new);
+ bat_dbg(DBG_ARP, bat_priv, "ARP request replied locally\n");
+ } else
+ /* Send the request on the DHT */
+ ret = dht_send_data(bat_priv, skb, ip_dst);
+out:
+ if (n)
+ neigh_release(n);
+ if (primary_if)
+ hardif_free_ref(primary_if);
+ return ret;
+}
+
+/* This function is meant to be invoked for an ARP request which is coming into
+ * the bat0 interfaces from the mesh network. It will check for the needed data
+ * into the local table. If found, an ARP reply is sent immediately, otherwise
+ * the caller has to deliver the ARP request to the upper layer */
+bool dat_snoop_incoming_arp_request(struct bat_priv *bat_priv,
+ struct sk_buff *skb)
+{
+ uint16_t type;
+ uint32_t ip_src, ip_dst;
+ uint8_t *hw_src;
+ struct hard_iface *primary_if = NULL;
+ struct sk_buff *skb_new;
+ struct neighbour *n = NULL;
+ bool ret = false;
+
+ type = arp_get_type(bat_priv, skb);
+ if (type != ARPOP_REQUEST)
+ goto out;
+
+ hw_src = ARP_HW_SRC(skb);
+ ip_src = ARP_IP_SRC(skb);
+ ip_dst = ARP_IP_DST(skb);
+
+ bat_dbg(DBG_ARP, bat_priv, "Parsing incoming ARP REQUEST\n");
+ bat_dbg_arp(bat_priv, skb, type);
+
+ primary_if = primary_if_get_selected(bat_priv);
+ if (!primary_if)
+ goto out;
+
+ arp_neigh_update(bat_priv, ip_src, hw_src);
+
+ n = neigh_lookup(&arp_tbl, &ip_dst, primary_if->soft_iface);
+ /* check if it is a valid neigh entry */
+ if (!n || !(n->nud_state & NUD_CONNECTED))
+ goto out;
+
+ skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
+ primary_if->soft_iface, ip_dst, hw_src, n->ha,
+ hw_src);
+
+ if (!skb_new)
+ goto out;
+
+ unicast_send_skb(skb_new, bat_priv);
+
+ ret = true;
+out:
+ if (n)
+ neigh_release(n);
+ if (primary_if)
+ hardif_free_ref(primary_if);
+ if (ret)
+ kfree_skb(skb);
+ return ret;
+}
+
+/* This function is meant to be invoked on an ARP reply packet going into the
+ * soft interface. The related neighbour entry has to be updated and the DHT has
+ * to be populated as well */
+bool dat_snoop_outgoing_arp_reply(struct bat_priv *bat_priv,
+ struct sk_buff *skb)
+{
+ uint16_t type;
+ uint32_t ip_src, ip_dst;
+ uint8_t *hw_src, *hw_dst;
+ bool ret = false;
+
+ type = arp_get_type(bat_priv, skb);
+ if (type != ARPOP_REPLY)
+ goto out;
+
+ bat_dbg(DBG_ARP, bat_priv, "Parsing outgoing ARP REPLY\n");
+ bat_dbg_arp(bat_priv, skb, type);
+
+ hw_src = ARP_HW_SRC(skb);
+ ip_src = ARP_IP_SRC(skb);
+ hw_dst = ARP_HW_DST(skb);
+ ip_dst = ARP_IP_DST(skb);
+
+ arp_neigh_update(bat_priv, ip_src, hw_src);
+ arp_neigh_update(bat_priv, ip_dst, hw_dst);
+
+ /* Send the ARP reply to the candidates for both the IP addresses we
+ * fetched from the ARP reply */
+ dht_send_data(bat_priv, skb, ip_src);
+ dht_send_data(bat_priv, skb, ip_dst);
+ ret = true;
+out:
+ return ret;
+}
+
+/* This function has to be invoked on an ARP reply coming into the soft
+ * interface from the mesh network. The local table has to be updated */
+bool dat_snoop_incoming_arp_reply(struct bat_priv *bat_priv,
+ struct sk_buff *skb)
+{
+ uint16_t type;
+ uint32_t ip_src, ip_dst;
+ uint8_t *hw_src, *hw_dst;
+ bool ret = false;
+
+ type = arp_get_type(bat_priv, skb);
+ if (type != ARPOP_REPLY)
+ goto out;
+
+ bat_dbg(DBG_ARP, bat_priv, "Parsing incoming ARP REPLY\n");
+ bat_dbg_arp(bat_priv, skb, type);
+
+ hw_src = ARP_HW_SRC(skb);
+ ip_src = ARP_IP_SRC(skb);
+ hw_dst = ARP_HW_DST(skb);
+ ip_dst = ARP_IP_DST(skb);
+
+ /* Update our internal cache with both the IP addresses we fetched from
+ * the ARP reply */
+ arp_neigh_update(bat_priv, ip_src, hw_src);
+ arp_neigh_update(bat_priv, ip_dst, hw_dst);
+
+ /* if this REPLY is directed to a client of mine, let's deliver the
+ * packet to the interface */
+ ret = !is_my_client(bat_priv, hw_dst);
+out:
+ /* if ret == false packet has to be delivered to the interface */
+ return ret;
+}
+
+bool arp_drop_broadcast_packet(struct bat_priv *bat_priv,
+ struct forw_packet *forw_packet)
+{
+ struct neighbour *n;
+
+ /* If this packet is an ARP_REQUEST and we already have the information
+ * that it is going to ask, we can drop the packet */
+ if (!forw_packet->num_packets &&
+ (arp_get_type(bat_priv, forw_packet->skb) ==
+ ARPOP_REQUEST)) {
+ n = neigh_lookup(&arp_tbl, &ARP_IP_DST(forw_packet->skb),
+ forw_packet->if_incoming->soft_iface);
+ /* check if we already know this neigh */
+ if (n && (n->nud_state & NUD_CONNECTED)) {
+ bat_dbg(DBG_ARP, bat_priv, "ARP Request for %pI4: "
+ "fallback prevented\n",
+ &ARP_IP_DST(forw_packet->skb));
+ return true;
+ }
+
+ bat_dbg(DBG_ARP, bat_priv, "ARP Request for %pI4: fallback\n",
+ &ARP_IP_DST(forw_packet->skb));
+ }
+ return false;
+}
@@ -27,6 +27,7 @@
#include <linux/if_arp.h>
struct bat_priv;
+struct forw_packet;
/*
* dat_addr_t is the type used for all DHT indexes. If it is changed,
@@ -43,6 +44,17 @@ struct bat_priv;
#define ARP_HW_DST(skb) (ARP_HW_SRC(skb) + ETH_ALEN + 4)
#define ARP_IP_DST(skb) (*(uint32_t *)(ARP_HW_SRC(skb) + ETH_ALEN * 2 + 4))
+bool dat_snoop_outgoing_arp_request(struct bat_priv *bat_priv,
+ struct sk_buff *skb);
+bool dat_snoop_incoming_arp_request(struct bat_priv *bat_priv,
+ struct sk_buff *skb);
+bool dat_snoop_outgoing_arp_reply(struct bat_priv *bat_priv,
+ struct sk_buff *skb);
+bool dat_snoop_incoming_arp_reply(struct bat_priv *bat_priv,
+ struct sk_buff *skb);
+bool arp_drop_broadcast_packet(struct bat_priv *bat_priv,
+ struct forw_packet *forw_packet);
+
/* hash function to choose an entry in a hash table of given size */
/* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */
static inline uint32_t hash_ipv4(const void *data, uint32_t size)
@@ -67,6 +67,8 @@
#define NUM_WORDS BITS_TO_LONGS(TQ_LOCAL_WINDOW_SIZE)
+/* msecs after which an ARP_REQUEST is sent in broadcast as fallback */
+#define ARP_REQ_DELAY 250
/* numbers of originator to contact for any STORE/GET DHT operation */
#define DHT_CANDIDATES_NUM 3
@@ -20,6 +20,7 @@
*/
#include "main.h"
+#include "distributed-arp-table.h"
#include "send.h"
#include "routing.h"
#include "translation-table.h"
@@ -29,6 +30,8 @@
#include "gateway_common.h"
#include "originator.h"
+#include <net/arp.h>
+
static void send_outstanding_bcast_packet(struct work_struct *work);
/* send out an already prepared packet to the given address via the
@@ -274,6 +277,9 @@ static void send_outstanding_bcast_packet(struct work_struct *work)
if (atomic_read(&bat_priv->mesh_state) == MESH_DEACTIVATING)
goto out;
+ if (arp_drop_broadcast_packet(bat_priv, forw_packet))
+ goto out;
+
/* rebroadcast packet */
rcu_read_lock();
list_for_each_entry_rcu(hard_iface, &hardif_list, list) {
@@ -22,6 +22,7 @@
#include "main.h"
#include "soft-interface.h"
#include "hard-interface.h"
+#include "distributed-arp-table.h"
#include "routing.h"
#include "send.h"
#include "bat_debugfs.h"
@@ -134,6 +135,7 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
int data_len = skb->len, ret;
short vid = -1;
bool do_bcast = false;
+ unsigned long brd_delay = 1;
if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
goto dropped;
@@ -194,6 +196,9 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
if (!primary_if)
goto dropped;
+ if (dat_snoop_outgoing_arp_request(bat_priv, skb))
+ brd_delay = msecs_to_jiffies(ARP_REQ_DELAY);
+
if (my_skb_head_push(skb, sizeof(*bcast_packet)) < 0)
goto dropped;
@@ -213,7 +218,7 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
bcast_packet->seqno =
htonl(atomic_inc_return(&bat_priv->bcast_seqno));
- add_bcast_packet_to_list(bat_priv, skb, 1);
+ add_bcast_packet_to_list(bat_priv, skb, brd_delay);
/* a copy is stored in the bcast list, therefore removing
* the original skb. */
@@ -227,6 +232,8 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
goto dropped;
}
+ dat_snoop_outgoing_arp_reply(bat_priv, skb);
+
ret = unicast_send_skb(skb, bat_priv);
if (ret != 0)
goto dropped_freed;
@@ -277,6 +284,12 @@ void interface_rx(struct net_device *soft_iface,
goto dropped;
}
+ if (dat_snoop_incoming_arp_request(bat_priv, skb))
+ goto out;
+
+ if (dat_snoop_incoming_arp_reply(bat_priv, skb))
+ goto out;
+
/* skb->dev & skb->pkt_type are set here */
if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
goto dropped;