Merge tag 'batman-adv-for-davem' of git://git.open-mesh.org/linux-merge

Included changes:
- minimal fixes to the packet layout to avoid the __packed attribute when not
  needed
- new packet type called UNICAST_4ADDR: in this packet it is possible to find
  both source and destination node (in the classic UNICAST header only the
  destination field exists).
- a new feature: Distributed ARP Table (D.A.T.). It aims to reduce ARP lookups
  latency by means of a simil-DHT approach.

Documentation/networking/batman-adv.txt

@@ -203,7 +203,8 @@ abled  during run time. Following log_levels are defined:
 2 - Enable messages related to route added / changed / deleted
 4 - Enable messages related to translation table operations
 8 - Enable messages related to bridge loop avoidance
-15 - enable all messages
+16 - Enable messaged related to DAT, ARP snooping and parsing
+31 - Enable all messages
 
 The debug output can be changed at runtime  using  the  file
 /sys/class/net/bat0/mesh/log_level. e.g.

net/batman-adv/Kconfig

@@ -25,6 +25,16 @@ config BATMAN_ADV_BLA
 	  more than one mesh node in the same LAN, you can safely remove
 	  this feature and save some space.
 
+config BATMAN_ADV_DAT
+	bool "Distributed ARP Table"
+	depends on BATMAN_ADV && INET
+	default n
+	help
+	  This option enables DAT (Distributed ARP Table), a DHT based
+	  mechanism that increases ARP reliability on sparse wireless
+	  mesh networks. If you think that your network does not need
+	  this option you can safely remove it and save some space.
+
 config BATMAN_ADV_DEBUG
 	bool "B.A.T.M.A.N. debugging"
 	depends on BATMAN_ADV

net/batman-adv/Makefile

@@ -23,6 +23,7 @@ batman-adv-y += bat_iv_ogm.o
 batman-adv-y += bitarray.o
 batman-adv-$(CONFIG_BATMAN_ADV_BLA) += bridge_loop_avoidance.o
 batman-adv-y += debugfs.o
+batman-adv-$(CONFIG_BATMAN_ADV_DAT) += distributed-arp-table.o
 batman-adv-y += gateway_client.o
 batman-adv-y += gateway_common.o
 batman-adv-y += hard-interface.o

net/batman-adv/bat_iv_ogm.c

@@ -411,9 +411,11 @@ static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
 
 	if ((atomic_read(&bat_priv->aggregated_ogms)) &&
 	    (packet_len < BATADV_MAX_AGGREGATION_BYTES))
-		skb_size = BATADV_MAX_AGGREGATION_BYTES + ETH_HLEN;
+		skb_size = BATADV_MAX_AGGREGATION_BYTES;
 	else
-		skb_size = packet_len + ETH_HLEN;
+		skb_size = packet_len;
+
+	skb_size += ETH_HLEN + NET_IP_ALIGN;
 
 	forw_packet_aggr->skb = dev_alloc_skb(skb_size);
 	if (!forw_packet_aggr->skb) {
@@ -422,7 +424,7 @@ static void batadv_iv_ogm_aggregate_new(const unsigned char *packet_buff,
 		kfree(forw_packet_aggr);
 		goto out;
 	}
-	skb_reserve(forw_packet_aggr->skb, ETH_HLEN);
+	skb_reserve(forw_packet_aggr->skb, ETH_HLEN + NET_IP_ALIGN);
 
 	INIT_HLIST_NODE(&forw_packet_aggr->list);
 

net/batman-adv/debugfs.c

@@ -31,6 +31,7 @@
 #include "vis.h"
 #include "icmp_socket.h"
 #include "bridge_loop_avoidance.h"
+#include "distributed-arp-table.h"
 
 static struct dentry *batadv_debugfs;
 
@@ -280,6 +281,19 @@ static int batadv_bla_backbone_table_open(struct inode *inode,
 
 #endif
 
+#ifdef CONFIG_BATMAN_ADV_DAT
+/**
+ * batadv_dat_cache_open - Prepare file handler for reads from dat_chache
+ * @inode: inode which was opened
+ * @file: file handle to be initialized
+ */
+static int batadv_dat_cache_open(struct inode *inode, struct file *file)
+{
+	struct net_device *net_dev = (struct net_device *)inode->i_private;
+	return single_open(file, batadv_dat_cache_seq_print_text, net_dev);
+}
+#endif
+
 static int batadv_transtable_local_open(struct inode *inode, struct file *file)
 {
 	struct net_device *net_dev = (struct net_device *)inode->i_private;
@@ -319,6 +333,9 @@ static BATADV_DEBUGINFO(bla_claim_table, S_IRUGO, batadv_bla_claim_table_open);
 static BATADV_DEBUGINFO(bla_backbone_table, S_IRUGO,
 			batadv_bla_backbone_table_open);
 #endif
+#ifdef CONFIG_BATMAN_ADV_DAT
+static BATADV_DEBUGINFO(dat_cache, S_IRUGO, batadv_dat_cache_open);
+#endif
 static BATADV_DEBUGINFO(transtable_local, S_IRUGO,
 			batadv_transtable_local_open);
 static BATADV_DEBUGINFO(vis_data, S_IRUGO, batadv_vis_data_open);
@@ -330,6 +347,9 @@ static struct batadv_debuginfo *batadv_mesh_debuginfos[] = {
 #ifdef CONFIG_BATMAN_ADV_BLA
 	&batadv_debuginfo_bla_claim_table,
 	&batadv_debuginfo_bla_backbone_table,
+#endif
+#ifdef CONFIG_BATMAN_ADV_DAT
+	&batadv_debuginfo_dat_cache,
 #endif
 	&batadv_debuginfo_transtable_local,
 	&batadv_debuginfo_vis_data,

net/batman-adv/distributed-arp-table.h

+/* Copyright (C) 2011-2012 B.A.T.M.A.N. contributors:
+ *
+ * Antonio Quartulli
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA
+ */
+
+#ifndef _NET_BATMAN_ADV_ARP_H_
+#define _NET_BATMAN_ADV_ARP_H_
+
+#ifdef CONFIG_BATMAN_ADV_DAT
+
+#include "types.h"
+#include "originator.h"
+
+#include <linux/if_arp.h>
+
+#define BATADV_DAT_ADDR_MAX ((batadv_dat_addr_t)~(batadv_dat_addr_t)0)
+
+bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
+					   struct sk_buff *skb);
+bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
+					   struct sk_buff *skb, int hdr_size);
+void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv,
+					 struct sk_buff *skb);
+bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
+					 struct sk_buff *skb, int hdr_size);
+bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv,
+				      struct batadv_forw_packet *forw_packet);
+
+/**
+ * batadv_dat_init_orig_node_addr - assign a DAT address to the orig_node
+ * @orig_node: the node to assign the DAT address to
+ */
+static inline void
+batadv_dat_init_orig_node_addr(struct batadv_orig_node *orig_node)
+{
+	uint32_t addr;
+
+	addr = batadv_choose_orig(orig_node->orig, BATADV_DAT_ADDR_MAX);
+	orig_node->dat_addr = (batadv_dat_addr_t)addr;
+}
+
+/**
+ * batadv_dat_init_own_addr - assign a DAT address to the node itself
+ * @bat_priv: the bat priv with all the soft interface information
+ * @primary_if: a pointer to the primary interface
+ */
+static inline void
+batadv_dat_init_own_addr(struct batadv_priv *bat_priv,
+			 struct batadv_hard_iface *primary_if)
+{
+	uint32_t addr;
+
+	addr = batadv_choose_orig(primary_if->net_dev->dev_addr,
+				  BATADV_DAT_ADDR_MAX);
+
+	bat_priv->dat.addr = (batadv_dat_addr_t)addr;
+}
+
+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);
+
+/**
+ * batadv_dat_inc_counter - increment the correct DAT packet counter
+ * @bat_priv: the bat priv with all the soft interface information
+ * @subtype: the 4addr subtype of the packet to be counted
+ *
+ * Updates the ethtool statistics for the received packet if it is a DAT subtype
+ */
+static inline void batadv_dat_inc_counter(struct batadv_priv *bat_priv,
+					  uint8_t subtype)
+{
+	switch (subtype) {
+	case BATADV_P_DAT_DHT_GET:
+		batadv_inc_counter(bat_priv,
+				   BATADV_CNT_DAT_GET_RX);
+		break;
+	case BATADV_P_DAT_DHT_PUT:
+		batadv_inc_counter(bat_priv,
+				   BATADV_CNT_DAT_PUT_RX);
+		break;
+	}
+}
+
+#else
+
+static inline bool
+batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
+				      struct sk_buff *skb)
+{
+	return false;
+}
+
+static inline bool
+batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
+				      struct sk_buff *skb, int hdr_size)
+{
+	return false;
+}
+
+static inline bool
+batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv,
+				    struct sk_buff *skb)
+{
+	return false;
+}
+
+static inline bool
+batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
+				    struct sk_buff *skb, int hdr_size)
+{
+	return false;
+}
+
+static inline bool
+batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv,
+				 struct batadv_forw_packet *forw_packet)
+{
+	return false;
+}
+
+static inline void
+batadv_dat_init_orig_node_addr(struct batadv_orig_node *orig_node)
+{
+}
+
+static inline void batadv_dat_init_own_addr(struct batadv_priv *bat_priv,
+					    struct batadv_hard_iface *iface)
+{
+}
+
+static inline void batadv_arp_change_timeout(struct net_device *soft_iface,
+					     const char *name)
+{
+}
+
+static inline int batadv_dat_init(struct batadv_priv *bat_priv)
+{
+	return 0;
+}
+
+static inline void batadv_dat_free(struct batadv_priv *bat_priv)
+{
+}
+
+static inline void batadv_dat_inc_counter(struct batadv_priv *bat_priv,
+					  uint8_t subtype)
+{
+}
+
+#endif /* CONFIG_BATMAN_ADV_DAT */
+
+#endif /* _NET_BATMAN_ADV_ARP_H_ */

net/batman-adv/hard-interface.c

@@ -18,6 +18,7 @@
  */
 
 #include "main.h"
+#include "distributed-arp-table.h"
 #include "hard-interface.h"
 #include "soft-interface.h"
 #include "send.h"
@@ -109,6 +110,8 @@ static void batadv_primary_if_update_addr(struct batadv_priv *bat_priv,
 	if (!primary_if)
 		goto out;
 
+	batadv_dat_init_own_addr(bat_priv, primary_if);
+
 	skb = bat_priv->vis.my_info->skb_packet;
 	vis_packet = (struct batadv_vis_packet *)skb->data;
 	memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN);

net/batman-adv/icmp_socket.c

@@ -177,13 +177,13 @@ static ssize_t batadv_socket_write(struct file *file, const char __user *buff,
 	if (len >= sizeof(struct batadv_icmp_packet_rr))
 		packet_len = sizeof(struct batadv_icmp_packet_rr);
 
-	skb = dev_alloc_skb(packet_len + ETH_HLEN);
+	skb = dev_alloc_skb(packet_len + ETH_HLEN + NET_IP_ALIGN);
 	if (!skb) {
 		len = -ENOMEM;
 		goto out;
 	}
 
-	skb_reserve(skb, ETH_HLEN);
+	skb_reserve(skb, ETH_HLEN + NET_IP_ALIGN);
 	icmp_packet = (struct batadv_icmp_packet_rr *)skb_put(skb, packet_len);
 
 	if (copy_from_user(icmp_packet, buff, packet_len)) {

net/batman-adv/main.c

@@ -29,6 +29,7 @@
 #include "hard-interface.h"
 #include "gateway_client.h"
 #include "bridge_loop_avoidance.h"
+#include "distributed-arp-table.h"
 #include "vis.h"
 #include "hash.h"
 #include "bat_algo.h"
@@ -128,6 +129,10 @@ int batadv_mesh_init(struct net_device *soft_iface)
 	if (ret < 0)
 		goto err;
 
+	ret = batadv_dat_init(bat_priv);
+	if (ret < 0)
+		goto err;
+
 	atomic_set(&bat_priv->gw.reselect, 0);
 	atomic_set(&bat_priv->mesh_state, BATADV_MESH_ACTIVE);
 
@@ -155,6 +160,8 @@ void batadv_mesh_free(struct net_device *soft_iface)
 
 	batadv_bla_free(bat_priv);
 
+	batadv_dat_free(bat_priv);
+
 	free_percpu(bat_priv->bat_counters);
 
 	atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
@@ -300,6 +307,8 @@ static void batadv_recv_handler_init(void)
 
 	/* batman icmp packet */
 	batadv_rx_handler[BATADV_ICMP] = batadv_recv_icmp_packet;
+	/* unicast with 4 addresses packet */
+	batadv_rx_handler[BATADV_UNICAST_4ADDR] = batadv_recv_unicast_packet;
 	/* unicast packet */
 	batadv_rx_handler[BATADV_UNICAST] = batadv_recv_unicast_packet;
 	/* fragmented unicast packet */

net/batman-adv/main.h

@@ -44,6 +44,7 @@
 #define BATADV_TT_LOCAL_TIMEOUT 3600000 /* in milliseconds */
 #define BATADV_TT_CLIENT_ROAM_TIMEOUT 600000 /* in milliseconds */
 #define BATADV_TT_CLIENT_TEMP_TIMEOUT 600000 /* in milliseconds */
+#define BATADV_DAT_ENTRY_TIMEOUT (5*60000) /* 5 mins in milliseconds */
 /* sliding packet range of received originator messages in sequence numbers
  * (should be a multiple of our word size)
  */
@@ -73,6 +74,11 @@
 
 #define BATADV_LOG_BUF_LEN 8192	  /* has to be a power of 2 */
 
+/* msecs after which an ARP_REQUEST is sent in broadcast as fallback */
+#define ARP_REQ_DELAY 250
+/* numbers of originator to contact for any PUT/GET DHT operation */
+#define BATADV_DAT_CANDIDATES_NUM 3
+
 #define BATADV_VIS_INTERVAL 5000	/* 5 seconds */
 
 /* how much worse secondary interfaces may be to be considered as bonding
@@ -117,6 +123,9 @@ enum batadv_uev_type {
 
 #define BATADV_GW_THRESHOLD	50
 
+#define BATADV_DAT_CANDIDATE_NOT_FOUND	0
+#define BATADV_DAT_CANDIDATE_ORIG	1
+
 /* Debug Messages */
 #ifdef pr_fmt
 #undef pr_fmt
@@ -171,6 +180,7 @@ int batadv_algo_seq_print_text(struct seq_file *seq, void *offset);
  * @BATADV_DBG_ROUTES: route added / changed / deleted
  * @BATADV_DBG_TT: translation table messages
  * @BATADV_DBG_BLA: bridge loop avoidance messages
+ * @BATADV_DBG_DAT: ARP snooping and DAT related messages
  * @BATADV_DBG_ALL: the union of all the above log levels
  */
 enum batadv_dbg_level {
@@ -178,7 +188,8 @@ enum batadv_dbg_level {
 	BATADV_DBG_ROUTES = BIT(1),
 	BATADV_DBG_TT	  = BIT(2),
 	BATADV_DBG_BLA    = BIT(3),
-	BATADV_DBG_ALL    = 15,
+	BATADV_DBG_DAT    = BIT(4),
+	BATADV_DBG_ALL    = 31,
 };
 
 #ifdef CONFIG_BATMAN_ADV_DEBUG

net/batman-adv/originator.c

@@ -18,6 +18,7 @@
  */
 
 #include "main.h"
+#include "distributed-arp-table.h"
 #include "originator.h"
 #include "hash.h"
 #include "translation-table.h"
@@ -223,6 +224,7 @@ struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
 	orig_node->tt_poss_change = false;
 	orig_node->bat_priv = bat_priv;
 	memcpy(orig_node->orig, addr, ETH_ALEN);
+	batadv_dat_init_orig_node_addr(orig_node);
 	orig_node->router = NULL;
 	orig_node->tt_crc = 0;
 	atomic_set(&orig_node->last_ttvn, 0);

net/batman-adv/packet.h

@@ -31,6 +31,21 @@ enum batadv_packettype {
 	BATADV_UNICAST_FRAG	= 0x06,
 	BATADV_TT_QUERY		= 0x07,
 	BATADV_ROAM_ADV		= 0x08,
+	BATADV_UNICAST_4ADDR	= 0x09,
+};
+
+/**
+ * enum batadv_subtype - packet subtype for unicast4addr
+ * @BATADV_P_DATA: user payload
+ * @BATADV_P_DAT_DHT_GET: DHT request message
+ * @BATADV_P_DAT_DHT_PUT: DHT store message
+ * @BATADV_P_DAT_CACHE_REPLY: ARP reply generated by DAT
+ */
+enum batadv_subtype {
+	BATADV_P_DATA			= 0x01,
+	BATADV_P_DAT_DHT_GET		= 0x02,
+	BATADV_P_DAT_DHT_PUT		= 0x03,
+	BATADV_P_DAT_CACHE_REPLY	= 0x04,
 };
 
 /* this file is included by batctl which needs these defines */
@@ -106,13 +121,16 @@ struct batadv_bla_claim_dst {
 	uint8_t magic[3];	/* FF:43:05 */
 	uint8_t type;		/* bla_claimframe */
 	__be16 group;		/* group id */
-} __packed;
+};
 
 struct batadv_header {
 	uint8_t  packet_type;
 	uint8_t  version;  /* batman version field */
 	uint8_t  ttl;
-} __packed;
+	/* the parent struct has to add a byte after the header to make
+	 * everything 4 bytes aligned again
+	 */
+};
 
 struct batadv_ogm_packet {
 	struct batadv_header header;
@@ -137,7 +155,7 @@ struct batadv_icmp_packet {
 	__be16   seqno;
 	uint8_t  uid;
 	uint8_t  reserved;
-} __packed;
+};
 
 #define BATADV_RR_LEN 16
 
@@ -153,13 +171,32 @@ struct batadv_icmp_packet_rr {
 	uint8_t  uid;
 	uint8_t  rr_cur;
 	uint8_t  rr[BATADV_RR_LEN][ETH_ALEN];
-} __packed;
+};
 
 struct batadv_unicast_packet {
 	struct batadv_header header;
 	uint8_t  ttvn; /* destination translation table version number */
 	uint8_t  dest[ETH_ALEN];
-} __packed;
+	/* "4 bytes boundary + 2 bytes" long to make the payload after the
+	 * following ethernet header again 4 bytes boundary aligned
+	 */
+};
+
+/**
+ * struct batadv_unicast_4addr_packet - extended unicast packet
+ * @u: common unicast packet header
+ * @src: address of the source
+ * @subtype: packet subtype
+ */
+struct batadv_unicast_4addr_packet {
+	struct batadv_unicast_packet u;
+	uint8_t src[ETH_ALEN];
+	uint8_t subtype;
+	uint8_t reserved;
+	/* "4 bytes boundary + 2 bytes" long to make the payload after the
+	 * following ethernet header again 4 bytes boundary aligned
+	 */
+};
 
 struct batadv_unicast_frag_packet {
 	struct batadv_header header;
@@ -176,6 +213,9 @@ struct batadv_bcast_packet {
 	uint8_t  reserved;
 	__be32   seqno;
 	uint8_t  orig[ETH_ALEN];
+	/* "4 bytes boundary + 2 bytes" long to make the payload after the
+	 * following ethernet header again 4 bytes boundary aligned
+	 */
 } __packed;
 
 struct batadv_vis_packet {
@@ -187,7 +227,7 @@ struct batadv_vis_packet {
 	uint8_t  vis_orig[ETH_ALEN];	/* originator reporting its neighbors */
 	uint8_t  target_orig[ETH_ALEN]; /* who should receive this packet */
 	uint8_t  sender_orig[ETH_ALEN]; /* who sent or forwarded this packet */
-} __packed;
+};
 
 struct batadv_tt_query_packet {
 	struct batadv_header header;

net/batman-adv/routing.c

@@ -28,6 +28,7 @@
 #include "vis.h"
 #include "unicast.h"
 #include "bridge_loop_avoidance.h"
+#include "distributed-arp-table.h"
 
 static int batadv_route_unicast_packet(struct sk_buff *skb,
 				       struct batadv_hard_iface *recv_if);
@@ -984,7 +985,19 @@ int batadv_recv_unicast_packet(struct sk_buff *skb,
 {
 	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
 	struct batadv_unicast_packet *unicast_packet;
+	struct batadv_unicast_4addr_packet *unicast_4addr_packet;
+	uint8_t *orig_addr;
+	struct batadv_orig_node *orig_node = NULL;
 	int hdr_size = sizeof(*unicast_packet);
+	bool is4addr;
+
+	unicast_packet = (struct batadv_unicast_packet *)skb->data;
+	unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
+
+	is4addr = unicast_packet->header.packet_type == BATADV_UNICAST_4ADDR;
+	/* the caller function should have already pulled 2 bytes */
+	if (is4addr)
+		hdr_size = sizeof(*unicast_4addr_packet);
 
 	if (batadv_check_unicast_packet(skb, hdr_size) < 0)
 		return NET_RX_DROP;
@@ -992,12 +1005,28 @@ int batadv_recv_unicast_packet(struct sk_buff *skb,
 	if (!batadv_check_unicast_ttvn(bat_priv, skb))
 		return NET_RX_DROP;
 
-	unicast_packet = (struct batadv_unicast_packet *)skb->data;
-
 	/* packet for me */
 	if (batadv_is_my_mac(unicast_packet->dest)) {
+		if (is4addr) {
+			batadv_dat_inc_counter(bat_priv,
+					       unicast_4addr_packet->subtype);
+			orig_addr = unicast_4addr_packet->src;
+			orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
+		}
+
+		if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
+							  hdr_size))
+			goto rx_success;
+		if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
+							hdr_size))
+			goto rx_success;
+
 		batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
-				    NULL);
+				    orig_node);
+
+rx_success:
+		if (orig_node)
+			batadv_orig_node_free_ref(orig_node);
 
 		return NET_RX_SUCCESS;
 	}
@@ -1034,8 +1063,17 @@ int batadv_recv_ucast_frag_packet(struct sk_buff *skb,
 		if (!new_skb)
 			return NET_RX_SUCCESS;
 
+		if (batadv_dat_snoop_incoming_arp_request(bat_priv, new_skb,
+							  hdr_size))
+			goto rx_success;
+		if (batadv_dat_snoop_incoming_arp_reply(bat_priv, new_skb,
+							hdr_size))
+			goto rx_success;
+
 		batadv_interface_rx(recv_if->soft_iface, new_skb, recv_if,
 				    sizeof(struct batadv_unicast_packet), NULL);
+
+rx_success:
 		return NET_RX_SUCCESS;
 	}
 
@@ -1127,9 +1165,16 @@ int batadv_recv_bcast_packet(struct sk_buff *skb,
 	if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
 		goto out;
 
+	if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
+		goto rx_success;
+	if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
+		goto rx_success;
+
 	/* broadcast for me */
 	batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
 			    orig_node);
+
+rx_success:
 	ret = NET_RX_SUCCESS;
 	goto out;
 

net/batman-adv/send.c

@@ -18,6 +18,7 @@
  */
 
 #include "main.h"
+#include "distributed-arp-table.h"
 #include "send.h"
 #include "routing.h"
 #include "translation-table.h"
@@ -209,6 +210,9 @@ static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
 	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 		goto out;
 
+	if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet))
+		goto out;
+
 	/* rebroadcast packet */
 	rcu_read_lock();
 	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {

net/batman-adv/soft-interface.c

@@ -20,6 +20,7 @@
 #include "main.h"
 #include "soft-interface.h"
 #include "hard-interface.h"
+#include "distributed-arp-table.h"
 #include "routing.h"
 #include "send.h"
 #include "debugfs.h"
@@ -155,6 +156,7 @@ static int batadv_interface_tx(struct sk_buff *skb,
 	short vid __maybe_unused = -1;
 	bool do_bcast = false;
 	uint32_t seqno;
+	unsigned long brd_delay = 1;
 
 	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 		goto dropped;
@@ -224,6 +226,13 @@ static int batadv_interface_tx(struct sk_buff *skb,
 		if (!primary_if)
 			goto dropped;
 
+		/* in case of ARP request, we do not immediately broadcasti the
+		 * packet, instead we first wait for DAT to try to retrieve the
+		 * correct ARP entry
+		 */
+		if (batadv_dat_snoop_outgoing_arp_request(bat_priv, skb))
+			brd_delay = msecs_to_jiffies(ARP_REQ_DELAY);
+
 		if (batadv_skb_head_push(skb, sizeof(*bcast_packet)) < 0)
 			goto dropped;
 
@@ -245,7 +254,7 @@ static int batadv_interface_tx(struct sk_buff *skb,
 		seqno = atomic_inc_return(&bat_priv->bcast_seqno);
 		bcast_packet->seqno = htonl(seqno);
 
-		batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
+		batadv_add_bcast_packet_to_list(bat_priv, skb, brd_delay);
 
 		/* a copy is stored in the bcast list, therefore removing
 		 * the original skb.
@@ -260,7 +269,12 @@ static int batadv_interface_tx(struct sk_buff *skb,
 				goto dropped;
 		}
 
-		ret = batadv_unicast_send_skb(skb, bat_priv);
+		if (batadv_dat_snoop_outgoing_arp_request(bat_priv, skb))
+			goto dropped;
+
+		batadv_dat_snoop_outgoing_arp_reply(bat_priv, skb);
+
+		ret = batadv_unicast_send_skb(bat_priv, skb);
 		if (ret != 0)
 			goto dropped_freed;
 	}
@@ -466,6 +480,9 @@ struct net_device *batadv_softif_create(const char *name)
 	atomic_set(&bat_priv->aggregated_ogms, 1);
 	atomic_set(&bat_priv->bonding, 0);
 	atomic_set(&bat_priv->bridge_loop_avoidance, 0);
+#ifdef CONFIG_BATMAN_ADV_DAT
+	atomic_set(&bat_priv->distributed_arp_table, 1);
+#endif
 	atomic_set(&bat_priv->ap_isolation, 0);
 	atomic_set(&bat_priv->vis_mode, BATADV_VIS_TYPE_CLIENT_UPDATE);
 	atomic_set(&bat_priv->gw_mode, BATADV_GW_MODE_OFF);
@@ -608,6 +625,13 @@ static const struct {
 	{ "tt_response_rx" },
 	{ "tt_roam_adv_tx" },
 	{ "tt_roam_adv_rx" },
+#ifdef CONFIG_BATMAN_ADV_DAT
+	{ "dat_get_tx" },
+	{ "dat_get_rx" },
+	{ "dat_put_tx" },
+	{ "dat_put_rx" },
+	{ "dat_cached_reply_tx" },
+#endif
 };
 
 static void batadv_get_strings(struct net_device *dev, uint32_t stringset,

net/batman-adv/sysfs.c

@@ -20,6 +20,7 @@
 #include "main.h"
 #include "sysfs.h"
 #include "translation-table.h"
+#include "distributed-arp-table.h"
 #include "originator.h"
 #include "hard-interface.h"
 #include "gateway_common.h"
@@ -420,6 +421,9 @@ BATADV_ATTR_SIF_BOOL(bonding, S_IRUGO | S_IWUSR, NULL);
 #ifdef CONFIG_BATMAN_ADV_BLA
 BATADV_ATTR_SIF_BOOL(bridge_loop_avoidance, S_IRUGO | S_IWUSR, NULL);
 #endif
+#ifdef CONFIG_BATMAN_ADV_DAT
+BATADV_ATTR_SIF_BOOL(distributed_arp_table, S_IRUGO | S_IWUSR, NULL);
+#endif
 BATADV_ATTR_SIF_BOOL(fragmentation, S_IRUGO | S_IWUSR, batadv_update_min_mtu);
 BATADV_ATTR_SIF_BOOL(ap_isolation, S_IRUGO | S_IWUSR, NULL);
 static BATADV_ATTR(vis_mode, S_IRUGO | S_IWUSR, batadv_show_vis_mode,
@@ -444,6 +448,9 @@ static struct batadv_attribute *batadv_mesh_attrs[] = {
 	&batadv_attr_bonding,
 #ifdef CONFIG_BATMAN_ADV_BLA
 	&batadv_attr_bridge_loop_avoidance,
+#endif
+#ifdef CONFIG_BATMAN_ADV_DAT
+	&batadv_attr_distributed_arp_table,
 #endif
 	&batadv_attr_fragmentation,
 	&batadv_attr_ap_isolation,

net/batman-adv/translation-table.c

@@ -1472,11 +1472,11 @@ batadv_tt_response_fill_table(uint16_t tt_len, uint8_t ttvn,
 	tt_tot = tt_len / sizeof(struct batadv_tt_change);
 
 	len = tt_query_size + tt_len;
-	skb = dev_alloc_skb(len + ETH_HLEN);
+	skb = dev_alloc_skb(len + ETH_HLEN + NET_IP_ALIGN);
 	if (!skb)
 		goto out;
 
-	skb_reserve(skb, ETH_HLEN);
+	skb_reserve(skb, ETH_HLEN + NET_IP_ALIGN);
 	tt_response = (struct batadv_tt_query_packet *)skb_put(skb, len);
 	tt_response->ttvn = ttvn;
 
@@ -1538,11 +1538,11 @@ static int batadv_send_tt_request(struct batadv_priv *bat_priv,
 	if (!tt_req_node)
 		goto out;
 
-	skb = dev_alloc_skb(sizeof(*tt_request) + ETH_HLEN);
+	skb = dev_alloc_skb(sizeof(*tt_request) + ETH_HLEN + NET_IP_ALIGN);
 	if (!skb)
 		goto out;
 
-	skb_reserve(skb, ETH_HLEN);
+	skb_reserve(skb, ETH_HLEN + NET_IP_ALIGN);
 
 	tt_req_len = sizeof(*tt_request);
 	tt_request = (struct batadv_tt_query_packet *)skb_put(skb, tt_req_len);
@@ -1653,11 +1653,11 @@ batadv_send_other_tt_response(struct batadv_priv *bat_priv,
 		tt_tot = tt_len / sizeof(struct batadv_tt_change);
 
 		len = sizeof(*tt_response) + tt_len;
-		skb = dev_alloc_skb(len + ETH_HLEN);
+		skb = dev_alloc_skb(len + ETH_HLEN + NET_IP_ALIGN);
 		if (!skb)
 			goto unlock;
 
-		skb_reserve(skb, ETH_HLEN);
+		skb_reserve(skb, ETH_HLEN + NET_IP_ALIGN);
 		packet_pos = skb_put(skb, len);
 		tt_response = (struct batadv_tt_query_packet *)packet_pos;
 		tt_response->ttvn = req_ttvn;
@@ -1780,11 +1780,11 @@ batadv_send_my_tt_response(struct batadv_priv *bat_priv,
 		tt_tot = tt_len / sizeof(struct batadv_tt_change);
 
 		len = sizeof(*tt_response) + tt_len;
-		skb = dev_alloc_skb(len + ETH_HLEN);
+		skb = dev_alloc_skb(len + ETH_HLEN + NET_IP_ALIGN);
 		if (!skb)
 			goto unlock;
 
-		skb_reserve(skb, ETH_HLEN);
+		skb_reserve(skb, ETH_HLEN + NET_IP_ALIGN);
 		packet_pos = skb_put(skb, len);
 		tt_response = (struct batadv_tt_query_packet *)packet_pos;
 		tt_response->ttvn = req_ttvn;
@@ -2118,11 +2118,11 @@ static void batadv_send_roam_adv(struct batadv_priv *bat_priv, uint8_t *client,
 	if (!batadv_tt_check_roam_count(bat_priv, client))
 		goto out;
 
-	skb = dev_alloc_skb(sizeof(*roam_adv_packet) + ETH_HLEN);
+	skb = dev_alloc_skb(sizeof(*roam_adv_packet) + ETH_HLEN + NET_IP_ALIGN);
 	if (!skb)
 		goto out;
 
-	skb_reserve(skb, ETH_HLEN);
+	skb_reserve(skb, ETH_HLEN + NET_IP_ALIGN);
 
 	roam_adv_packet = (struct batadv_roam_adv_packet *)skb_put(skb, len);
 

net/batman-adv/types.h

@@ -28,6 +28,17 @@
 	(ETH_HLEN + max(sizeof(struct batadv_unicast_packet), \
 			sizeof(struct batadv_bcast_packet)))
 
+#ifdef CONFIG_BATMAN_ADV_DAT
+
+/* batadv_dat_addr_t is the type used for all DHT addresses. If it is changed,
+ * BATADV_DAT_ADDR_MAX is changed as well.
+ *
+ * *Please be careful: batadv_dat_addr_t must be UNSIGNED*
+ */
+#define batadv_dat_addr_t uint16_t
+
+#endif /* CONFIG_BATMAN_ADV_DAT */
+
 /**
  * struct batadv_hard_iface_bat_iv - per hard interface B.A.T.M.A.N. IV data
  * @ogm_buff: buffer holding the OGM packet
@@ -73,6 +84,9 @@ struct batadv_orig_node {
 	uint8_t orig[ETH_ALEN];
 	uint8_t primary_addr[ETH_ALEN];
 	struct batadv_neigh_node __rcu *router; /* rcu protected pointer */
+#ifdef CONFIG_BATMAN_ADV_DAT
+	batadv_dat_addr_t dat_addr;
+#endif
 	unsigned long *bcast_own;
 	uint8_t *bcast_own_sum;
 	unsigned long last_seen;
@@ -172,6 +186,13 @@ enum batadv_counters {
 	BATADV_CNT_TT_RESPONSE_RX,
 	BATADV_CNT_TT_ROAM_ADV_TX,
 	BATADV_CNT_TT_ROAM_ADV_RX,
+#ifdef CONFIG_BATMAN_ADV_DAT
+	BATADV_CNT_DAT_GET_TX,
+	BATADV_CNT_DAT_GET_RX,
+	BATADV_CNT_DAT_PUT_TX,
+	BATADV_CNT_DAT_PUT_RX,
+	BATADV_CNT_DAT_CACHED_REPLY_TX,
+#endif
 	BATADV_CNT_NUM,
 };
 
@@ -238,6 +259,20 @@ struct batadv_priv_vis {
 	struct batadv_vis_info *my_info;
 };
 
+/**
+ * struct batadv_priv_dat - per mesh interface DAT private data
+ * @addr: node DAT address
+ * @hash: hashtable representing the local ARP cache
+ * @work: work queue callback item for cache purging
+ */
+#ifdef CONFIG_BATMAN_ADV_DAT
+struct batadv_priv_dat {
+	batadv_dat_addr_t addr;
+	struct batadv_hashtable *hash;
+	struct delayed_work work;
+};
+#endif
+
 struct batadv_priv {
 	atomic_t mesh_state;
 	struct net_device_stats stats;
@@ -247,6 +282,9 @@ struct batadv_priv {
 	atomic_t fragmentation;		/* boolean */
 	atomic_t ap_isolation;		/* boolean */
 	atomic_t bridge_loop_avoidance;	/* boolean */
+#ifdef CONFIG_BATMAN_ADV_DAT
+	atomic_t distributed_arp_table;	/* boolean */
+#endif
 	atomic_t vis_mode;		/* VIS_TYPE_* */
 	atomic_t gw_mode;		/* GW_MODE_* */
 	atomic_t gw_sel_class;		/* uint */
@@ -275,6 +313,9 @@ struct batadv_priv {
 	struct batadv_priv_gw gw;
 	struct batadv_priv_tt tt;
 	struct batadv_priv_vis vis;
+#ifdef CONFIG_BATMAN_ADV_DAT
+	struct batadv_priv_dat dat;
+#endif
 };
 
 struct batadv_socket_client {
@@ -447,4 +488,36 @@ struct batadv_algo_ops {
 	void (*bat_ogm_emit)(struct batadv_forw_packet *forw_packet);
 };
 
+/**
+ * struct batadv_dat_entry - it is a single entry of batman-adv ARP backend. It
+ * is used to stored ARP entries needed for the global DAT cache
+ * @ip: the IPv4 corresponding to this DAT/ARP entry
+ * @mac_addr: the MAC address associated to the stored IPv4
+ * @last_update: time in jiffies when this entry was refreshed last time
+ * @hash_entry: hlist node for batadv_priv_dat::hash
+ * @refcount: number of contexts the object is used
+ * @rcu: struct used for freeing in an RCU-safe manner
+ */
+struct batadv_dat_entry {
+	__be32 ip;
+	uint8_t mac_addr[ETH_ALEN];
+	unsigned long last_update;
+	struct hlist_node hash_entry;
+	atomic_t refcount;
+	struct rcu_head rcu;
+};
+
+/**
+ * struct batadv_dat_candidate - candidate destination for DAT operations
+ * @type: the type of the selected candidate. It can one of the following:
+ *	  - BATADV_DAT_CANDIDATE_NOT_FOUND
+ *	  - BATADV_DAT_CANDIDATE_ORIG
+ * @orig_node: if type is BATADV_DAT_CANDIDATE_ORIG this field points to the
+ *	       corresponding originator node structure
+ */
+struct batadv_dat_candidate {
+	int type;
+	struct batadv_orig_node *orig_node;
+};
+
 #endif /* _NET_BATMAN_ADV_TYPES_H_ */

net/batman-adv/unicast.c

@@ -291,7 +291,111 @@ int batadv_frag_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv,
 	return ret;
 }
 
-int batadv_unicast_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv)
+/**
+ * batadv_unicast_push_and_fill_skb - extends the buffer and initializes the
+ * common fields for unicast packets
+ * @skb: packet
+ * @hdr_size: amount of bytes to push at the beginning of the skb
+ * @orig_node: the destination node
+ *
+ * Returns false if the buffer extension was not possible or true otherwise
+ */
+static bool batadv_unicast_push_and_fill_skb(struct sk_buff *skb, int hdr_size,
+					     struct batadv_orig_node *orig_node)
+{
+	struct batadv_unicast_packet *unicast_packet;
+	uint8_t ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
+
+	if (batadv_skb_head_push(skb, hdr_size) < 0)
+		return false;
+
+	unicast_packet = (struct batadv_unicast_packet *)skb->data;
+	unicast_packet->header.version = BATADV_COMPAT_VERSION;
+	/* batman packet type: unicast */
+	unicast_packet->header.packet_type = BATADV_UNICAST;
+	/* set unicast ttl */
+	unicast_packet->header.ttl = BATADV_TTL;
+	/* copy the destination for faster routing */
+	memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
+	/* set the destination tt version number */
+	unicast_packet->ttvn = ttvn;
+
+	return true;
+}
+
+/**
+ * batadv_unicast_prepare_skb - encapsulate an skb with a unicast header
+ * @skb: the skb containing the payload to encapsulate
+ * @orig_node: the destination node
+ *
+ * Returns false if the payload could not be encapsulated or true otherwise
+ */
+static bool batadv_unicast_prepare_skb(struct sk_buff *skb,
+				       struct batadv_orig_node *orig_node)
+{
+	size_t uni_size = sizeof(struct batadv_unicast_packet);
+	return batadv_unicast_push_and_fill_skb(skb, uni_size, orig_node);
+}
+
+/**
+ * batadv_unicast_4addr_prepare_skb - encapsulate an skb with a unicast4addr
+ * header
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: the skb containing the payload to encapsulate
+ * @orig_node: the destination node
+ * @packet_subtype: the batman 4addr packet subtype to use
+ *
+ * Returns false if the payload could not be encapsulated or true otherwise
+ */
+bool batadv_unicast_4addr_prepare_skb(struct batadv_priv *bat_priv,
+				      struct sk_buff *skb,
+				      struct batadv_orig_node *orig,
+				      int packet_subtype)
+{
+	struct batadv_hard_iface *primary_if;
+	struct batadv_unicast_4addr_packet *unicast_4addr_packet;
+	bool ret = false;
+
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (!primary_if)
+		goto out;
+
+	/* pull the header space and fill the unicast_packet substructure.
+	 * We can do that because the first member of the unicast_4addr_packet
+	 * is of type struct unicast_packet
+	 */
+	if (!batadv_unicast_push_and_fill_skb(skb,
+					      sizeof(*unicast_4addr_packet),
+					      orig))
+		goto out;
+
+	unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
+	unicast_4addr_packet->u.header.packet_type = BATADV_UNICAST_4ADDR;
+	memcpy(unicast_4addr_packet->src, primary_if->net_dev->dev_addr,
+	       ETH_ALEN);
+	unicast_4addr_packet->subtype = packet_subtype;
+	unicast_4addr_packet->reserved = 0;
+
+	ret = true;
+out:
+	if (primary_if)
+		batadv_hardif_free_ref(primary_if);
+	return ret;
+}
+
+/**
+ * batadv_unicast_generic_send_skb - send an skb as unicast
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: payload to send
+ * @packet_type: the batman unicast packet type to use
+ * @packet_subtype: the batman packet subtype. It is ignored if packet_type is
+ *		    not BATADV_UNICAT_4ADDR
+ *
+ * Returns 1 in case of error or 0 otherwise
+ */
+int batadv_unicast_generic_send_skb(struct batadv_priv *bat_priv,
+				    struct sk_buff *skb, int packet_type,
+				    int packet_subtype)
 {
 	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 	struct batadv_unicast_packet *unicast_packet;
@@ -324,21 +428,23 @@ int batadv_unicast_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv)
 	if (!neigh_node)
 		goto out;
 
-	if (batadv_skb_head_push(skb, sizeof(*unicast_packet)) < 0)
+	switch (packet_type) {
+	case BATADV_UNICAST:
+		batadv_unicast_prepare_skb(skb, orig_node);
+		break;
+	case BATADV_UNICAST_4ADDR:
+		batadv_unicast_4addr_prepare_skb(bat_priv, skb, orig_node,
+						 packet_subtype);
+		break;
+	default:
+		/* this function supports UNICAST and UNICAST_4ADDR only. It
+		 * should never be invoked with any other packet type
+		 */
 		goto out;
+	}
 
 	unicast_packet = (struct batadv_unicast_packet *)skb->data;
 
-	unicast_packet->header.version = BATADV_COMPAT_VERSION;
-	/* batman packet type: unicast */
-	unicast_packet->header.packet_type = BATADV_UNICAST;
-	/* set unicast ttl */
-	unicast_packet->header.ttl = BATADV_TTL;
-	/* copy the destination for faster routing */
-	memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
-	/* set the destination tt version number */
-	unicast_packet->ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
-
 	/* inform the destination node that we are still missing a correct route
 	 * for this client. The destination will receive this packet and will
 	 * try to reroute it because the ttvn contained in the header is less
@@ -348,7 +454,9 @@ int batadv_unicast_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv)
 		unicast_packet->ttvn = unicast_packet->ttvn - 1;
 
 	dev_mtu = neigh_node->if_incoming->net_dev->mtu;
-	if (atomic_read(&bat_priv->fragmentation) &&
+	/* fragmentation mechanism only works for UNICAST (now) */
+	if (packet_type == BATADV_UNICAST &&
+	    atomic_read(&bat_priv->fragmentation) &&
 	    data_len + sizeof(*unicast_packet) > dev_mtu) {
 		/* send frag skb decreases ttl */
 		unicast_packet->header.ttl++;
@@ -360,7 +468,6 @@ int batadv_unicast_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv)
 
 	batadv_send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr);
 	ret = 0;
-	goto out;
 
 out:
 	if (neigh_node)

net/batman-adv/unicast.h

@@ -29,10 +29,44 @@ int batadv_frag_reassemble_skb(struct sk_buff *skb,
 			       struct batadv_priv *bat_priv,
 			       struct sk_buff **new_skb);
 void batadv_frag_list_free(struct list_head *head);
-int batadv_unicast_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv);
 int batadv_frag_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv,
 			 struct batadv_hard_iface *hard_iface,
 			 const uint8_t dstaddr[]);
+bool batadv_unicast_4addr_prepare_skb(struct batadv_priv *bat_priv,
+				      struct sk_buff *skb,
+				      struct batadv_orig_node *orig_node,
+				      int packet_subtype);
+int batadv_unicast_generic_send_skb(struct batadv_priv *bat_priv,
+				    struct sk_buff *skb, int packet_type,
+				    int packet_subtype);
+
+
+/**
+ * batadv_unicast_send_skb - send the skb encapsulated in a unicast packet
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: the payload to send
+ */
+static inline int batadv_unicast_send_skb(struct batadv_priv *bat_priv,
+					  struct sk_buff *skb)
+{
+	return batadv_unicast_generic_send_skb(bat_priv, skb, BATADV_UNICAST,
+					       0);
+}
+
+/**
+ * batadv_unicast_send_skb - send the skb encapsulated in a unicast4addr packet
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: the payload to send
+ * @packet_subtype: the batman 4addr packet subtype to use
+ */
+static inline int batadv_unicast_4addr_send_skb(struct batadv_priv *bat_priv,
+						struct sk_buff *skb,
+						int packet_subtype)
+{
+	return batadv_unicast_generic_send_skb(bat_priv, skb,
+					       BATADV_UNICAST_4ADDR,
+					       packet_subtype);
+}
 
 static inline int batadv_frag_can_reassemble(const struct sk_buff *skb, int mtu)
 {

net/batman-adv/vis.c

@@ -396,12 +396,12 @@ batadv_add_packet(struct batadv_priv *bat_priv,
 		return NULL;
 
 	len = sizeof(*packet) + vis_info_len;
-	info->skb_packet = dev_alloc_skb(len + ETH_HLEN);
+	info->skb_packet = dev_alloc_skb(len + ETH_HLEN + NET_IP_ALIGN);
 	if (!info->skb_packet) {
 		kfree(info);
 		return NULL;
 	}
-	skb_reserve(info->skb_packet, ETH_HLEN);
+	skb_reserve(info->skb_packet, ETH_HLEN + NET_IP_ALIGN);
 	packet = (struct batadv_vis_packet *)skb_put(info->skb_packet, len);
 
 	kref_init(&info->refcount);
@@ -873,12 +873,13 @@ int batadv_vis_init(struct batadv_priv *bat_priv)
 	if (!bat_priv->vis.my_info)
 		goto err;
 
-	len = sizeof(*packet) + BATADV_MAX_VIS_PACKET_SIZE + ETH_HLEN;
+	len = sizeof(*packet) + BATADV_MAX_VIS_PACKET_SIZE;
+	len += ETH_HLEN + NET_IP_ALIGN;
 	bat_priv->vis.my_info->skb_packet = dev_alloc_skb(len);
 	if (!bat_priv->vis.my_info->skb_packet)
 		goto free_info;
 
-	skb_reserve(bat_priv->vis.my_info->skb_packet, ETH_HLEN);
+	skb_reserve(bat_priv->vis.my_info->skb_packet, ETH_HLEN + NET_IP_ALIGN);
 	tmp_skb = bat_priv->vis.my_info->skb_packet;
 	packet = (struct batadv_vis_packet *)skb_put(tmp_skb, sizeof(*packet));