Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1300 insertions, 0 deletions

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
new file mode 100644
index 000000000..98af41e38
--- /dev/null
+++ b/net/batman-adv/routing.c
@@ -0,0 +1,1300 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2007-2018  B.A.T.M.A.N. contributors:
+ *
+ * Marek Lindner, Simon Wunderlich
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "routing.h"
+#include "main.h"
+
+#include <linux/atomic.h>
+#include <linux/byteorder/generic.h>
+#include <linux/compiler.h>
+#include <linux/errno.h>
+#include <linux/etherdevice.h>
+#include <linux/if_ether.h>
+#include <linux/jiffies.h>
+#include <linux/kref.h>
+#include <linux/netdevice.h>
+#include <linux/printk.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <linux/stddef.h>
+#include <uapi/linux/batadv_packet.h>
+
+#include "bitarray.h"
+#include "bridge_loop_avoidance.h"
+#include "distributed-arp-table.h"
+#include "fragmentation.h"
+#include "hard-interface.h"
+#include "icmp_socket.h"
+#include "log.h"
+#include "network-coding.h"
+#include "originator.h"
+#include "send.h"
+#include "soft-interface.h"
+#include "tp_meter.h"
+#include "translation-table.h"
+#include "tvlv.h"
+
+static int batadv_route_unicast_packet(struct sk_buff *skb,
+				       struct batadv_hard_iface *recv_if);
+
+/**
+ * _batadv_update_route() - set the router for this originator
+ * @bat_priv: the bat priv with all the soft interface information
+ * @orig_node: orig node which is to be configured
+ * @recv_if: the receive interface for which this route is set
+ * @neigh_node: neighbor which should be the next router
+ *
+ * This function does not perform any error checks
+ */
+static void _batadv_update_route(struct batadv_priv *bat_priv,
+				 struct batadv_orig_node *orig_node,
+				 struct batadv_hard_iface *recv_if,
+				 struct batadv_neigh_node *neigh_node)
+{
+	struct batadv_orig_ifinfo *orig_ifinfo;
+	struct batadv_neigh_node *curr_router;
+
+	orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
+	if (!orig_ifinfo)
+		return;
+
+	spin_lock_bh(&orig_node->neigh_list_lock);
+	/* curr_router used earlier may not be the current orig_ifinfo->router
+	 * anymore because it was dereferenced outside of the neigh_list_lock
+	 * protected region. After the new best neighbor has replace the current
+	 * best neighbor the reference counter needs to decrease. Consequently,
+	 * the code needs to ensure the curr_router variable contains a pointer
+	 * to the replaced best neighbor.
+	 */
+	curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
+
+	/* increase refcount of new best neighbor */
+	if (neigh_node)
+		kref_get(&neigh_node->refcount);
+
+	rcu_assign_pointer(orig_ifinfo->router, neigh_node);
+	spin_unlock_bh(&orig_node->neigh_list_lock);
+	batadv_orig_ifinfo_put(orig_ifinfo);
+
+	/* route deleted */
+	if (curr_router && !neigh_node) {
+		batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
+			   "Deleting route towards: %pM\n", orig_node->orig);
+		batadv_tt_global_del_orig(bat_priv, orig_node, -1,
+					  "Deleted route towards originator");
+
+	/* route added */
+	} else if (!curr_router && neigh_node) {
+		batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
+			   "Adding route towards: %pM (via %pM)\n",
+			   orig_node->orig, neigh_node->addr);
+	/* route changed */
+	} else if (neigh_node && curr_router) {
+		batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
+			   "Changing route towards: %pM (now via %pM - was via %pM)\n",
+			   orig_node->orig, neigh_node->addr,
+			   curr_router->addr);
+	}
+
+	/* decrease refcount of previous best neighbor */
+	if (curr_router)
+		batadv_neigh_node_put(curr_router);
+}
+
+/**
+ * batadv_update_route() - set the router for this originator
+ * @bat_priv: the bat priv with all the soft interface information
+ * @orig_node: orig node which is to be configured
+ * @recv_if: the receive interface for which this route is set
+ * @neigh_node: neighbor which should be the next router
+ */
+void batadv_update_route(struct batadv_priv *bat_priv,
+			 struct batadv_orig_node *orig_node,
+			 struct batadv_hard_iface *recv_if,
+			 struct batadv_neigh_node *neigh_node)
+{
+	struct batadv_neigh_node *router = NULL;
+
+	if (!orig_node)
+		goto out;
+
+	router = batadv_orig_router_get(orig_node, recv_if);
+
+	if (router != neigh_node)
+		_batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
+
+out:
+	if (router)
+		batadv_neigh_node_put(router);
+}
+
+/**
+ * batadv_window_protected() - checks whether the host restarted and is in the
+ *  protection time.
+ * @bat_priv: the bat priv with all the soft interface information
+ * @seq_num_diff: difference between the current/received sequence number and
+ *  the last sequence number
+ * @seq_old_max_diff: maximum age of sequence number not considered as restart
+ * @last_reset: jiffies timestamp of the last reset, will be updated when reset
+ *  is detected
+ * @protection_started: is set to true if the protection window was started,
+ *   doesn't change otherwise.
+ *
+ * Return:
+ *  false if the packet is to be accepted.
+ *  true if the packet is to be ignored.
+ */
+bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
+			     s32 seq_old_max_diff, unsigned long *last_reset,
+			     bool *protection_started)
+{
+	if (seq_num_diff <= -seq_old_max_diff ||
+	    seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
+		if (!batadv_has_timed_out(*last_reset,
+					  BATADV_RESET_PROTECTION_MS))
+			return true;
+
+		*last_reset = jiffies;
+		if (protection_started)
+			*protection_started = true;
+		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+			   "old packet received, start protection\n");
+	}
+
+	return false;
+}
+
+/**
+ * batadv_check_management_packet() - Check preconditions for management packets
+ * @skb: incoming packet buffer
+ * @hard_iface: incoming hard interface
+ * @header_len: minimal header length of packet type
+ *
+ * Return: true when management preconditions are met, false otherwise
+ */
+bool batadv_check_management_packet(struct sk_buff *skb,
+				    struct batadv_hard_iface *hard_iface,
+				    int header_len)
+{
+	struct ethhdr *ethhdr;
+
+	/* drop packet if it has not necessary minimum size */
+	if (unlikely(!pskb_may_pull(skb, header_len)))
+		return false;
+
+	ethhdr = eth_hdr(skb);
+
+	/* packet with broadcast indication but unicast recipient */
+	if (!is_broadcast_ether_addr(ethhdr->h_dest))
+		return false;
+
+	/* packet with invalid sender address */
+	if (!is_valid_ether_addr(ethhdr->h_source))
+		return false;
+
+	/* create a copy of the skb, if needed, to modify it. */
+	if (skb_cow(skb, 0) < 0)
+		return false;
+
+	/* keep skb linear */
+	if (skb_linearize(skb) < 0)
+		return false;
+
+	return true;
+}
+
+/**
+ * batadv_recv_my_icmp_packet() - receive an icmp packet locally
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: icmp packet to process
+ *
+ * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
+ * otherwise.
+ */
+static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
+				      struct sk_buff *skb)
+{
+	struct batadv_hard_iface *primary_if = NULL;
+	struct batadv_orig_node *orig_node = NULL;
+	struct batadv_icmp_header *icmph;
+	int res, ret = NET_RX_DROP;
+
+	icmph = (struct batadv_icmp_header *)skb->data;
+
+	switch (icmph->msg_type) {
+	case BATADV_ECHO_REPLY:
+	case BATADV_DESTINATION_UNREACHABLE:
+	case BATADV_TTL_EXCEEDED:
+		/* receive the packet */
+		if (skb_linearize(skb) < 0)
+			break;
+
+		batadv_socket_receive_packet(icmph, skb->len);
+		break;
+	case BATADV_ECHO_REQUEST:
+		/* answer echo request (ping) */
+		primary_if = batadv_primary_if_get_selected(bat_priv);
+		if (!primary_if)
+			goto out;
+
+		/* get routing information */
+		orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
+		if (!orig_node)
+			goto out;
+
+		/* create a copy of the skb, if needed, to modify it. */
+		if (skb_cow(skb, ETH_HLEN) < 0)
+			goto out;
+
+		icmph = (struct batadv_icmp_header *)skb->data;
+
+		ether_addr_copy(icmph->dst, icmph->orig);
+		ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
+		icmph->msg_type = BATADV_ECHO_REPLY;
+		icmph->ttl = BATADV_TTL;
+
+		res = batadv_send_skb_to_orig(skb, orig_node, NULL);
+		if (res == NET_XMIT_SUCCESS)
+			ret = NET_RX_SUCCESS;
+
+		/* skb was consumed */
+		skb = NULL;
+		break;
+	case BATADV_TP:
+		if (!pskb_may_pull(skb, sizeof(struct batadv_icmp_tp_packet)))
+			goto out;
+
+		batadv_tp_meter_recv(bat_priv, skb);
+		ret = NET_RX_SUCCESS;
+		/* skb was consumed */
+		skb = NULL;
+		goto out;
+	default:
+		/* drop unknown type */
+		goto out;
+	}
+out:
+	if (primary_if)
+		batadv_hardif_put(primary_if);
+	if (orig_node)
+		batadv_orig_node_put(orig_node);
+
+	kfree_skb(skb);
+
+	return ret;
+}
+
+static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
+					 struct sk_buff *skb)
+{
+	struct batadv_hard_iface *primary_if = NULL;
+	struct batadv_orig_node *orig_node = NULL;
+	struct batadv_icmp_packet *icmp_packet;
+	int res, ret = NET_RX_DROP;
+
+	icmp_packet = (struct batadv_icmp_packet *)skb->data;
+
+	/* send TTL exceeded if packet is an echo request (traceroute) */
+	if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
+		pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
+			 icmp_packet->orig, icmp_packet->dst);
+		goto out;
+	}
+
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (!primary_if)
+		goto out;
+
+	/* get routing information */
+	orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
+	if (!orig_node)
+		goto out;
+
+	/* create a copy of the skb, if needed, to modify it. */
+	if (skb_cow(skb, ETH_HLEN) < 0)
+		goto out;
+
+	icmp_packet = (struct batadv_icmp_packet *)skb->data;
+
+	ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
+	ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
+	icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
+	icmp_packet->ttl = BATADV_TTL;
+
+	res = batadv_send_skb_to_orig(skb, orig_node, NULL);
+	if (res == NET_RX_SUCCESS)
+		ret = NET_XMIT_SUCCESS;
+
+	/* skb was consumed */
+	skb = NULL;
+
+out:
+	if (primary_if)
+		batadv_hardif_put(primary_if);
+	if (orig_node)
+		batadv_orig_node_put(orig_node);
+
+	kfree_skb(skb);
+
+	return ret;
+}
+
+/**
+ * batadv_recv_icmp_packet() - Process incoming icmp packet
+ * @skb: incoming packet buffer
+ * @recv_if: incoming hard interface
+ *
+ * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
+ */
+int batadv_recv_icmp_packet(struct sk_buff *skb,
+			    struct batadv_hard_iface *recv_if)
+{
+	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
+	struct batadv_icmp_header *icmph;
+	struct batadv_icmp_packet_rr *icmp_packet_rr;
+	struct ethhdr *ethhdr;
+	struct batadv_orig_node *orig_node = NULL;
+	int hdr_size = sizeof(struct batadv_icmp_header);
+	int res, ret = NET_RX_DROP;
+
+	/* drop packet if it has not necessary minimum size */
+	if (unlikely(!pskb_may_pull(skb, hdr_size)))
+		goto free_skb;
+
+	ethhdr = eth_hdr(skb);
+
+	/* packet with unicast indication but non-unicast recipient */
+	if (!is_valid_ether_addr(ethhdr->h_dest))
+		goto free_skb;
+
+	/* packet with broadcast/multicast sender address */
+	if (is_multicast_ether_addr(ethhdr->h_source))
+		goto free_skb;
+
+	/* not for me */
+	if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
+		goto free_skb;
+
+	icmph = (struct batadv_icmp_header *)skb->data;
+
+	/* add record route information if not full */
+	if ((icmph->msg_type == BATADV_ECHO_REPLY ||
+	     icmph->msg_type == BATADV_ECHO_REQUEST) &&
+	    skb->len >= sizeof(struct batadv_icmp_packet_rr)) {
+		if (skb_linearize(skb) < 0)
+			goto free_skb;
+
+		/* create a copy of the skb, if needed, to modify it. */
+		if (skb_cow(skb, ETH_HLEN) < 0)
+			goto free_skb;
+
+		ethhdr = eth_hdr(skb);
+		icmph = (struct batadv_icmp_header *)skb->data;
+		icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
+		if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
+			goto free_skb;
+
+		ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
+				ethhdr->h_dest);
+		icmp_packet_rr->rr_cur++;
+	}
+
+	/* packet for me */
+	if (batadv_is_my_mac(bat_priv, icmph->dst))
+		return batadv_recv_my_icmp_packet(bat_priv, skb);
+
+	/* TTL exceeded */
+	if (icmph->ttl < 2)
+		return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
+
+	/* get routing information */
+	orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
+	if (!orig_node)
+		goto free_skb;
+
+	/* create a copy of the skb, if needed, to modify it. */
+	if (skb_cow(skb, ETH_HLEN) < 0)
+		goto put_orig_node;
+
+	icmph = (struct batadv_icmp_header *)skb->data;
+
+	/* decrement ttl */
+	icmph->ttl--;
+
+	/* route it */
+	res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
+	if (res == NET_XMIT_SUCCESS)
+		ret = NET_RX_SUCCESS;
+
+	/* skb was consumed */
+	skb = NULL;
+
+put_orig_node:
+	if (orig_node)
+		batadv_orig_node_put(orig_node);
+free_skb:
+	kfree_skb(skb);
+
+	return ret;
+}
+
+/**
+ * batadv_check_unicast_packet() - Check for malformed unicast packets
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: packet to check
+ * @hdr_size: size of header to pull
+ *
+ * Check for short header and bad addresses in given packet.
+ *
+ * Return: negative value when check fails and 0 otherwise. The negative value
+ * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
+ * destination or source, and -EREMOTE for non-local (other host) destination.
+ */
+static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
+				       struct sk_buff *skb, int hdr_size)
+{
+	struct ethhdr *ethhdr;
+
+	/* drop packet if it has not necessary minimum size */
+	if (unlikely(!pskb_may_pull(skb, hdr_size)))
+		return -ENODATA;
+
+	ethhdr = eth_hdr(skb);
+
+	/* packet with unicast indication but non-unicast recipient */
+	if (!is_valid_ether_addr(ethhdr->h_dest))
+		return -EBADR;
+
+	/* packet with broadcast/multicast sender address */
+	if (is_multicast_ether_addr(ethhdr->h_source))
+		return -EBADR;
+
+	/* not for me */
+	if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
+		return -EREMOTE;
+
+	return 0;
+}
+
+/**
+ * batadv_last_bonding_get() - Get last_bonding_candidate of orig_node
+ * @orig_node: originator node whose last bonding candidate should be retrieved
+ *
+ * Return: last bonding candidate of router or NULL if not found
+ *
+ * The object is returned with refcounter increased by 1.
+ */
+static struct batadv_orig_ifinfo *
+batadv_last_bonding_get(struct batadv_orig_node *orig_node)
+{
+	struct batadv_orig_ifinfo *last_bonding_candidate;
+
+	spin_lock_bh(&orig_node->neigh_list_lock);
+	last_bonding_candidate = orig_node->last_bonding_candidate;
+
+	if (last_bonding_candidate)
+		kref_get(&last_bonding_candidate->refcount);
+	spin_unlock_bh(&orig_node->neigh_list_lock);
+
+	return last_bonding_candidate;
+}
+
+/**
+ * batadv_last_bonding_replace() - Replace last_bonding_candidate of orig_node
+ * @orig_node: originator node whose bonding candidates should be replaced
+ * @new_candidate: new bonding candidate or NULL
+ */
+static void
+batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
+			    struct batadv_orig_ifinfo *new_candidate)
+{
+	struct batadv_orig_ifinfo *old_candidate;
+
+	spin_lock_bh(&orig_node->neigh_list_lock);
+	old_candidate = orig_node->last_bonding_candidate;
+
+	if (new_candidate)
+		kref_get(&new_candidate->refcount);
+	orig_node->last_bonding_candidate = new_candidate;
+	spin_unlock_bh(&orig_node->neigh_list_lock);
+
+	if (old_candidate)
+		batadv_orig_ifinfo_put(old_candidate);
+}
+
+/**
+ * batadv_find_router() - find a suitable router for this originator
+ * @bat_priv: the bat priv with all the soft interface information
+ * @orig_node: the destination node
+ * @recv_if: pointer to interface this packet was received on
+ *
+ * Return: the router which should be used for this orig_node on
+ * this interface, or NULL if not available.
+ */
+struct batadv_neigh_node *
+batadv_find_router(struct batadv_priv *bat_priv,
+		   struct batadv_orig_node *orig_node,
+		   struct batadv_hard_iface *recv_if)
+{
+	struct batadv_algo_ops *bao = bat_priv->algo_ops;
+	struct batadv_neigh_node *first_candidate_router = NULL;
+	struct batadv_neigh_node *next_candidate_router = NULL;
+	struct batadv_neigh_node *router, *cand_router = NULL;
+	struct batadv_neigh_node *last_cand_router = NULL;
+	struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
+	struct batadv_orig_ifinfo *next_candidate = NULL;
+	struct batadv_orig_ifinfo *last_candidate;
+	bool last_candidate_found = false;
+
+	if (!orig_node)
+		return NULL;
+
+	router = batadv_orig_router_get(orig_node, recv_if);
+
+	if (!router)
+		return router;
+
+	/* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
+	 * and if activated.
+	 */
+	if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
+		return router;
+
+	/* bonding: loop through the list of possible routers found
+	 * for the various outgoing interfaces and find a candidate after
+	 * the last chosen bonding candidate (next_candidate). If no such
+	 * router is found, use the first candidate found (the previously
+	 * chosen bonding candidate might have been the last one in the list).
+	 * If this can't be found either, return the previously chosen
+	 * router - obviously there are no other candidates.
+	 */
+	rcu_read_lock();
+	last_candidate = batadv_last_bonding_get(orig_node);
+	if (last_candidate)
+		last_cand_router = rcu_dereference(last_candidate->router);
+
+	hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
+		/* acquire some structures and references ... */
+		if (!kref_get_unless_zero(&cand->refcount))
+			continue;
+
+		cand_router = rcu_dereference(cand->router);
+		if (!cand_router)
+			goto next;
+
+		if (!kref_get_unless_zero(&cand_router->refcount)) {
+			cand_router = NULL;
+			goto next;
+		}
+
+		/* alternative candidate should be good enough to be
+		 * considered
+		 */
+		if (!bao->neigh.is_similar_or_better(cand_router,
+						     cand->if_outgoing, router,
+						     recv_if))
+			goto next;
+
+		/* don't use the same router twice */
+		if (last_cand_router == cand_router)
+			goto next;
+
+		/* mark the first possible candidate */
+		if (!first_candidate) {
+			kref_get(&cand_router->refcount);
+			kref_get(&cand->refcount);
+			first_candidate = cand;
+			first_candidate_router = cand_router;
+		}
+
+		/* check if the loop has already passed the previously selected
+		 * candidate ... this function should select the next candidate
+		 * AFTER the previously used bonding candidate.
+		 */
+		if (!last_candidate || last_candidate_found) {
+			next_candidate = cand;
+			next_candidate_router = cand_router;
+			break;
+		}
+
+		if (last_candidate == cand)
+			last_candidate_found = true;
+next:
+		/* free references */
+		if (cand_router) {
+			batadv_neigh_node_put(cand_router);
+			cand_router = NULL;
+		}
+		batadv_orig_ifinfo_put(cand);
+	}
+	rcu_read_unlock();
+
+	/* After finding candidates, handle the three cases:
+	 * 1) there is a next candidate, use that
+	 * 2) there is no next candidate, use the first of the list
+	 * 3) there is no candidate at all, return the default router
+	 */
+	if (next_candidate) {
+		batadv_neigh_node_put(router);
+
+		kref_get(&next_candidate_router->refcount);
+		router = next_candidate_router;
+		batadv_last_bonding_replace(orig_node, next_candidate);
+	} else if (first_candidate) {
+		batadv_neigh_node_put(router);
+
+		kref_get(&first_candidate_router->refcount);
+		router = first_candidate_router;
+		batadv_last_bonding_replace(orig_node, first_candidate);
+	} else {
+		batadv_last_bonding_replace(orig_node, NULL);
+	}
+
+	/* cleanup of candidates */
+	if (first_candidate) {
+		batadv_neigh_node_put(first_candidate_router);
+		batadv_orig_ifinfo_put(first_candidate);
+	}
+
+	if (next_candidate) {
+		batadv_neigh_node_put(next_candidate_router);
+		batadv_orig_ifinfo_put(next_candidate);
+	}
+
+	if (last_candidate)
+		batadv_orig_ifinfo_put(last_candidate);
+
+	return router;
+}
+
+static int batadv_route_unicast_packet(struct sk_buff *skb,
+				       struct batadv_hard_iface *recv_if)
+{
+	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
+	struct batadv_orig_node *orig_node = NULL;
+	struct batadv_unicast_packet *unicast_packet;
+	struct ethhdr *ethhdr = eth_hdr(skb);
+	int res, hdr_len, ret = NET_RX_DROP;
+	unsigned int len;
+
+	unicast_packet = (struct batadv_unicast_packet *)skb->data;
+
+	/* TTL exceeded */
+	if (unicast_packet->ttl < 2) {
+		pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
+			 ethhdr->h_source, unicast_packet->dest);
+		goto free_skb;
+	}
+
+	/* get routing information */
+	orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
+
+	if (!orig_node)
+		goto free_skb;
+
+	/* create a copy of the skb, if needed, to modify it. */
+	if (skb_cow(skb, ETH_HLEN) < 0)
+		goto put_orig_node;
+
+	/* decrement ttl */
+	unicast_packet = (struct batadv_unicast_packet *)skb->data;
+	unicast_packet->ttl--;
+
+	switch (unicast_packet->packet_type) {
+	case BATADV_UNICAST_4ADDR:
+		hdr_len = sizeof(struct batadv_unicast_4addr_packet);
+		break;
+	case BATADV_UNICAST:
+		hdr_len = sizeof(struct batadv_unicast_packet);
+		break;
+	default:
+		/* other packet types not supported - yet */
+		hdr_len = -1;
+		break;
+	}
+
+	if (hdr_len > 0)
+		batadv_skb_set_priority(skb, hdr_len);
+
+	len = skb->len;
+	res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
+
+	/* translate transmit result into receive result */
+	if (res == NET_XMIT_SUCCESS) {
+		ret = NET_RX_SUCCESS;
+		/* skb was transmitted and consumed */
+		batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
+		batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
+				   len + ETH_HLEN);
+	}
+
+	/* skb was consumed */
+	skb = NULL;
+
+put_orig_node:
+	batadv_orig_node_put(orig_node);
+free_skb:
+	kfree_skb(skb);
+
+	return ret;
+}
+
+/**
+ * batadv_reroute_unicast_packet() - update the unicast header for re-routing
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: unicast packet to process
+ * @unicast_packet: the unicast header to be updated
+ * @dst_addr: the payload destination
+ * @vid: VLAN identifier
+ *
+ * Search the translation table for dst_addr and update the unicast header with
+ * the new corresponding information (originator address where the destination
+ * client currently is and its known TTVN)
+ *
+ * Return: true if the packet header has been updated, false otherwise
+ */
+static bool
+batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
+			      struct batadv_unicast_packet *unicast_packet,
+			      u8 *dst_addr, unsigned short vid)
+{
+	struct batadv_orig_node *orig_node = NULL;
+	struct batadv_hard_iface *primary_if = NULL;
+	bool ret = false;
+	u8 *orig_addr, orig_ttvn;
+
+	if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
+		primary_if = batadv_primary_if_get_selected(bat_priv);
+		if (!primary_if)
+			goto out;
+		orig_addr = primary_if->net_dev->dev_addr;
+		orig_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
+	} else {
+		orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
+						     vid);
+		if (!orig_node)
+			goto out;
+
+		if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
+			goto out;
+
+		orig_addr = orig_node->orig;
+		orig_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
+	}
+
+	/* update the packet header */
+	skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
+	ether_addr_copy(unicast_packet->dest, orig_addr);
+	unicast_packet->ttvn = orig_ttvn;
+	skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
+
+	ret = true;
+out:
+	if (primary_if)
+		batadv_hardif_put(primary_if);
+	if (orig_node)
+		batadv_orig_node_put(orig_node);
+
+	return ret;
+}
+
+static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
+				      struct sk_buff *skb, int hdr_len)
+{
+	struct batadv_unicast_packet *unicast_packet;
+	struct batadv_hard_iface *primary_if;
+	struct batadv_orig_node *orig_node;
+	u8 curr_ttvn, old_ttvn;
+	struct ethhdr *ethhdr;
+	unsigned short vid;
+	int is_old_ttvn;
+
+	/* check if there is enough data before accessing it */
+	if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
+		return false;
+
+	/* create a copy of the skb (in case of for re-routing) to modify it. */
+	if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
+		return false;
+
+	unicast_packet = (struct batadv_unicast_packet *)skb->data;
+	vid = batadv_get_vid(skb, hdr_len);
+	ethhdr = (struct ethhdr *)(skb->data + hdr_len);
+
+	/* do not reroute multicast frames in a unicast header */
+	if (is_multicast_ether_addr(ethhdr->h_dest))
+		return true;
+
+	/* check if the destination client was served by this node and it is now
+	 * roaming. In this case, it means that the node has got a ROAM_ADV
+	 * message and that it knows the new destination in the mesh to re-route
+	 * the packet to
+	 */
+	if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
+		if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
+						  ethhdr->h_dest, vid))
+			batadv_dbg_ratelimited(BATADV_DBG_TT,
+					       bat_priv,
+					       "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
+					       unicast_packet->dest,
+					       ethhdr->h_dest);
+		/* at this point the mesh destination should have been
+		 * substituted with the originator address found in the global
+		 * table. If not, let the packet go untouched anyway because
+		 * there is nothing the node can do
+		 */
+		return true;
+	}
+
+	/* retrieve the TTVN known by this node for the packet destination. This
+	 * value is used later to check if the node which sent (or re-routed
+	 * last time) the packet had an updated information or not
+	 */
+	curr_ttvn = (u8)atomic_read(&bat_priv->tt.vn);
+	if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
+		orig_node = batadv_orig_hash_find(bat_priv,
+						  unicast_packet->dest);
+		/* if it is not possible to find the orig_node representing the
+		 * destination, the packet can immediately be dropped as it will
+		 * not be possible to deliver it
+		 */
+		if (!orig_node)
+			return false;
+
+		curr_ttvn = (u8)atomic_read(&orig_node->last_ttvn);
+		batadv_orig_node_put(orig_node);
+	}
+
+	/* check if the TTVN contained in the packet is fresher than what the
+	 * node knows
+	 */
+	is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
+	if (!is_old_ttvn)
+		return true;
+
+	old_ttvn = unicast_packet->ttvn;
+	/* the packet was forged based on outdated network information. Its
+	 * destination can possibly be updated and forwarded towards the new
+	 * target host
+	 */
+	if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
+					  ethhdr->h_dest, vid)) {
+		batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
+				       "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
+				       unicast_packet->dest, ethhdr->h_dest,
+				       old_ttvn, curr_ttvn);
+		return true;
+	}
+
+	/* the packet has not been re-routed: either the destination is
+	 * currently served by this node or there is no destination at all and
+	 * it is possible to drop the packet
+	 */
+	if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
+		return false;
+
+	/* update the header in order to let the packet be delivered to this
+	 * node's soft interface
+	 */
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (!primary_if)
+		return false;
+
+	/* update the packet header */
+	skb_postpull_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
+	ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
+	unicast_packet->ttvn = curr_ttvn;
+	skb_postpush_rcsum(skb, unicast_packet, sizeof(*unicast_packet));
+
+	batadv_hardif_put(primary_if);
+
+	return true;
+}
+
+/**
+ * batadv_recv_unhandled_unicast_packet() - receive and process packets which
+ *	are in the unicast number space but not yet known to the implementation
+ * @skb: unicast tvlv packet to process
+ * @recv_if: pointer to interface this packet was received on
+ *
+ * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
+ * otherwise.
+ */
+int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
+					 struct batadv_hard_iface *recv_if)
+{
+	struct batadv_unicast_packet *unicast_packet;
+	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
+	int check, hdr_size = sizeof(*unicast_packet);
+
+	check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
+	if (check < 0)
+		goto free_skb;
+
+	/* we don't know about this type, drop it. */
+	unicast_packet = (struct batadv_unicast_packet *)skb->data;
+	if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
+		goto free_skb;
+
+	return batadv_route_unicast_packet(skb, recv_if);
+
+free_skb:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+/**
+ * batadv_recv_unicast_packet() - Process incoming unicast packet
+ * @skb: incoming packet buffer
+ * @recv_if: incoming hard interface
+ *
+ * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
+ */
+int batadv_recv_unicast_packet(struct sk_buff *skb,
+			       struct batadv_hard_iface *recv_if)
+{
+	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;
+	u8 *orig_addr, *orig_addr_gw;
+	struct batadv_orig_node *orig_node = NULL, *orig_node_gw = NULL;
+	int check, hdr_size = sizeof(*unicast_packet);
+	enum batadv_subtype subtype;
+	int ret = NET_RX_DROP;
+	bool is4addr, is_gw;
+
+	unicast_packet = (struct batadv_unicast_packet *)skb->data;
+	is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
+	/* the caller function should have already pulled 2 bytes */
+	if (is4addr)
+		hdr_size = sizeof(*unicast_4addr_packet);
+
+	/* function returns -EREMOTE for promiscuous packets */
+	check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
+
+	/* Even though the packet is not for us, we might save it to use for
+	 * decoding a later received coded packet
+	 */
+	if (check == -EREMOTE)
+		batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
+
+	if (check < 0)
+		goto free_skb;
+	if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
+		goto free_skb;
+
+	unicast_packet = (struct batadv_unicast_packet *)skb->data;
+
+	/* packet for me */
+	if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
+		/* If this is a unicast packet from another backgone gw,
+		 * drop it.
+		 */
+		orig_addr_gw = eth_hdr(skb)->h_source;
+		orig_node_gw = batadv_orig_hash_find(bat_priv, orig_addr_gw);
+		if (orig_node_gw) {
+			is_gw = batadv_bla_is_backbone_gw(skb, orig_node_gw,
+							  hdr_size);
+			batadv_orig_node_put(orig_node_gw);
+			if (is_gw) {
+				batadv_dbg(BATADV_DBG_BLA, bat_priv,
+					   "%s(): Dropped unicast pkt received from another backbone gw %pM.\n",
+					   __func__, orig_addr_gw);
+				goto free_skb;
+			}
+		}
+
+		if (is4addr) {
+			unicast_4addr_packet =
+				(struct batadv_unicast_4addr_packet *)skb->data;
+			subtype = unicast_4addr_packet->subtype;
+			batadv_dat_inc_counter(bat_priv, subtype);
+
+			/* Only payload data should be considered for speedy
+			 * join. For example, DAT also uses unicast 4addr
+			 * types, but those packets should not be considered
+			 * for speedy join, since the clients do not actually
+			 * reside at the sending originator.
+			 */
+			if (subtype == BATADV_P_DATA) {
+				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, hdr_size,
+				    orig_node);
+
+rx_success:
+		if (orig_node)
+			batadv_orig_node_put(orig_node);
+
+		return NET_RX_SUCCESS;
+	}
+
+	ret = batadv_route_unicast_packet(skb, recv_if);
+	/* skb was consumed */
+	skb = NULL;
+
+free_skb:
+	kfree_skb(skb);
+
+	return ret;
+}
+
+/**
+ * batadv_recv_unicast_tvlv() - receive and process unicast tvlv packets
+ * @skb: unicast tvlv packet to process
+ * @recv_if: pointer to interface this packet was received on
+ *
+ * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
+ * otherwise.
+ */
+int batadv_recv_unicast_tvlv(struct sk_buff *skb,
+			     struct batadv_hard_iface *recv_if)
+{
+	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
+	struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
+	unsigned char *tvlv_buff;
+	u16 tvlv_buff_len;
+	int hdr_size = sizeof(*unicast_tvlv_packet);
+	int ret = NET_RX_DROP;
+
+	if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
+		goto free_skb;
+
+	/* the header is likely to be modified while forwarding */
+	if (skb_cow(skb, hdr_size) < 0)
+		goto free_skb;
+
+	/* packet needs to be linearized to access the tvlv content */
+	if (skb_linearize(skb) < 0)
+		goto free_skb;
+
+	unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
+
+	tvlv_buff = (unsigned char *)(skb->data + hdr_size);
+	tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
+
+	if (tvlv_buff_len > skb->len - hdr_size)
+		goto free_skb;
+
+	ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
+					     unicast_tvlv_packet->src,
+					     unicast_tvlv_packet->dst,
+					     tvlv_buff, tvlv_buff_len);
+
+	if (ret != NET_RX_SUCCESS) {
+		ret = batadv_route_unicast_packet(skb, recv_if);
+		/* skb was consumed */
+		skb = NULL;
+	}
+
+free_skb:
+	kfree_skb(skb);
+
+	return ret;
+}
+
+/**
+ * batadv_recv_frag_packet() - process received fragment
+ * @skb: the received fragment
+ * @recv_if: interface that the skb is received on
+ *
+ * This function does one of the three following things: 1) Forward fragment, if
+ * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
+ * lack further fragments; 3) Merge fragments, if we have all needed parts.
+ *
+ * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
+ */
+int batadv_recv_frag_packet(struct sk_buff *skb,
+			    struct batadv_hard_iface *recv_if)
+{
+	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
+	struct batadv_orig_node *orig_node_src = NULL;
+	struct batadv_frag_packet *frag_packet;
+	int ret = NET_RX_DROP;
+
+	if (batadv_check_unicast_packet(bat_priv, skb,
+					sizeof(*frag_packet)) < 0)
+		goto free_skb;
+
+	frag_packet = (struct batadv_frag_packet *)skb->data;
+	orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
+	if (!orig_node_src)
+		goto free_skb;
+
+	skb->priority = frag_packet->priority + 256;
+
+	/* Route the fragment if it is not for us and too big to be merged. */
+	if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
+	    batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
+		/* skb was consumed */
+		skb = NULL;
+		ret = NET_RX_SUCCESS;
+		goto put_orig_node;
+	}
+
+	batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
+	batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
+
+	/* Add fragment to buffer and merge if possible. */
+	if (!batadv_frag_skb_buffer(&skb, orig_node_src))
+		goto put_orig_node;
+
+	/* Deliver merged packet to the appropriate handler, if it was
+	 * merged
+	 */
+	if (skb) {
+		batadv_batman_skb_recv(skb, recv_if->net_dev,
+				       &recv_if->batman_adv_ptype, NULL);
+		/* skb was consumed */
+		skb = NULL;
+	}
+
+	ret = NET_RX_SUCCESS;
+
+put_orig_node:
+	batadv_orig_node_put(orig_node_src);
+free_skb:
+	kfree_skb(skb);
+
+	return ret;
+}
+
+/**
+ * batadv_recv_bcast_packet() - Process incoming broadcast packet
+ * @skb: incoming packet buffer
+ * @recv_if: incoming hard interface
+ *
+ * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
+ */
+int batadv_recv_bcast_packet(struct sk_buff *skb,
+			     struct batadv_hard_iface *recv_if)
+{
+	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
+	struct batadv_orig_node *orig_node = NULL;
+	struct batadv_bcast_packet *bcast_packet;
+	struct ethhdr *ethhdr;
+	int hdr_size = sizeof(*bcast_packet);
+	int ret = NET_RX_DROP;
+	s32 seq_diff;
+	u32 seqno;
+
+	/* drop packet if it has not necessary minimum size */
+	if (unlikely(!pskb_may_pull(skb, hdr_size)))
+		goto free_skb;
+
+	ethhdr = eth_hdr(skb);
+
+	/* packet with broadcast indication but unicast recipient */
+	if (!is_broadcast_ether_addr(ethhdr->h_dest))
+		goto free_skb;
+
+	/* packet with broadcast/multicast sender address */
+	if (is_multicast_ether_addr(ethhdr->h_source))
+		goto free_skb;
+
+	/* ignore broadcasts sent by myself */
+	if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
+		goto free_skb;
+
+	bcast_packet = (struct batadv_bcast_packet *)skb->data;
+
+	/* ignore broadcasts originated by myself */
+	if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
+		goto free_skb;
+
+	if (bcast_packet->ttl < 2)
+		goto free_skb;
+
+	orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
+
+	if (!orig_node)
+		goto free_skb;
+
+	spin_lock_bh(&orig_node->bcast_seqno_lock);
+
+	seqno = ntohl(bcast_packet->seqno);
+	/* check whether the packet is a duplicate */
+	if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
+			    seqno))
+		goto spin_unlock;
+
+	seq_diff = seqno - orig_node->last_bcast_seqno;
+
+	/* check whether the packet is old and the host just restarted. */
+	if (batadv_window_protected(bat_priv, seq_diff,
+				    BATADV_BCAST_MAX_AGE,
+				    &orig_node->bcast_seqno_reset, NULL))
+		goto spin_unlock;
+
+	/* mark broadcast in flood history, update window position
+	 * if required.
+	 */
+	if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
+		orig_node->last_bcast_seqno = seqno;
+
+	spin_unlock_bh(&orig_node->bcast_seqno_lock);
+
+	/* check whether this has been sent by another originator before */
+	if (batadv_bla_check_bcast_duplist(bat_priv, skb))
+		goto free_skb;
+
+	batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
+
+	/* rebroadcast packet */
+	batadv_add_bcast_packet_to_list(bat_priv, skb, 1, false);
+
+	/* don't hand the broadcast up if it is from an originator
+	 * from the same backbone.
+	 */
+	if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
+		goto free_skb;
+
+	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, hdr_size, orig_node);
+
+rx_success:
+	ret = NET_RX_SUCCESS;
+	goto out;
+
+spin_unlock:
+	spin_unlock_bh(&orig_node->bcast_seqno_lock);
+free_skb:
+	kfree_skb(skb);
+out:
+	if (orig_node)
+		batadv_orig_node_put(orig_node);
+	return ret;
+}