Adding upstream version 6.1.76.upstream/6.1.76

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

1 files changed, 1135 insertions, 0 deletions

diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c
new file mode 100644
index 000000000..0379b1268
--- /dev/null
+++ b/net/batman-adv/send.c
@@ -0,0 +1,1135 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) B.A.T.M.A.N. contributors:
+ *
+ * Marek Lindner, Simon Wunderlich
+ */
+
+#include "send.h"
+#include "main.h"
+
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <linux/byteorder/generic.h>
+#include <linux/container_of.h>
+#include <linux/errno.h>
+#include <linux/etherdevice.h>
+#include <linux/gfp.h>
+#include <linux/if.h>
+#include <linux/if_ether.h>
+#include <linux/jiffies.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/netdevice.h>
+#include <linux/printk.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/stddef.h>
+#include <linux/workqueue.h>
+
+#include "distributed-arp-table.h"
+#include "fragmentation.h"
+#include "gateway_client.h"
+#include "hard-interface.h"
+#include "log.h"
+#include "network-coding.h"
+#include "originator.h"
+#include "routing.h"
+#include "soft-interface.h"
+#include "translation-table.h"
+
+static void batadv_send_outstanding_bcast_packet(struct work_struct *work);
+
+/**
+ * batadv_send_skb_packet() - send an already prepared packet
+ * @skb: the packet to send
+ * @hard_iface: the interface to use to send the broadcast packet
+ * @dst_addr: the payload destination
+ *
+ * Send out an already prepared packet to the given neighbor or broadcast it
+ * using the specified interface. Either hard_iface or neigh_node must be not
+ * NULL.
+ * If neigh_node is NULL, then the packet is broadcasted using hard_iface,
+ * otherwise it is sent as unicast to the given neighbor.
+ *
+ * Regardless of the return value, the skb is consumed.
+ *
+ * Return: A negative errno code is returned on a failure. A success does not
+ * guarantee the frame will be transmitted as it may be dropped due
+ * to congestion or traffic shaping.
+ */
+int batadv_send_skb_packet(struct sk_buff *skb,
+			   struct batadv_hard_iface *hard_iface,
+			   const u8 *dst_addr)
+{
+	struct batadv_priv *bat_priv;
+	struct ethhdr *ethhdr;
+	int ret;
+
+	bat_priv = netdev_priv(hard_iface->soft_iface);
+
+	if (hard_iface->if_status != BATADV_IF_ACTIVE)
+		goto send_skb_err;
+
+	if (unlikely(!hard_iface->net_dev))
+		goto send_skb_err;
+
+	if (!(hard_iface->net_dev->flags & IFF_UP)) {
+		pr_warn("Interface %s is not up - can't send packet via that interface!\n",
+			hard_iface->net_dev->name);
+		goto send_skb_err;
+	}
+
+	/* push to the ethernet header. */
+	if (batadv_skb_head_push(skb, ETH_HLEN) < 0)
+		goto send_skb_err;
+
+	skb_reset_mac_header(skb);
+
+	ethhdr = eth_hdr(skb);
+	ether_addr_copy(ethhdr->h_source, hard_iface->net_dev->dev_addr);
+	ether_addr_copy(ethhdr->h_dest, dst_addr);
+	ethhdr->h_proto = htons(ETH_P_BATMAN);
+
+	skb_set_network_header(skb, ETH_HLEN);
+	skb->protocol = htons(ETH_P_BATMAN);
+
+	skb->dev = hard_iface->net_dev;
+
+	/* Save a clone of the skb to use when decoding coded packets */
+	batadv_nc_skb_store_for_decoding(bat_priv, skb);
+
+	/* dev_queue_xmit() returns a negative result on error.	 However on
+	 * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
+	 * (which is > 0). This will not be treated as an error.
+	 */
+	ret = dev_queue_xmit(skb);
+	return net_xmit_eval(ret);
+send_skb_err:
+	kfree_skb(skb);
+	return NET_XMIT_DROP;
+}
+
+/**
+ * batadv_send_broadcast_skb() - Send broadcast packet via hard interface
+ * @skb: packet to be transmitted (with batadv header and no outer eth header)
+ * @hard_iface: outgoing interface
+ *
+ * Return: A negative errno code is returned on a failure. A success does not
+ * guarantee the frame will be transmitted as it may be dropped due
+ * to congestion or traffic shaping.
+ */
+int batadv_send_broadcast_skb(struct sk_buff *skb,
+			      struct batadv_hard_iface *hard_iface)
+{
+	return batadv_send_skb_packet(skb, hard_iface, batadv_broadcast_addr);
+}
+
+/**
+ * batadv_send_unicast_skb() - Send unicast packet to neighbor
+ * @skb: packet to be transmitted (with batadv header and no outer eth header)
+ * @neigh: neighbor which is used as next hop to destination
+ *
+ * Return: A negative errno code is returned on a failure. A success does not
+ * guarantee the frame will be transmitted as it may be dropped due
+ * to congestion or traffic shaping.
+ */
+int batadv_send_unicast_skb(struct sk_buff *skb,
+			    struct batadv_neigh_node *neigh)
+{
+#ifdef CONFIG_BATMAN_ADV_BATMAN_V
+	struct batadv_hardif_neigh_node *hardif_neigh;
+#endif
+	int ret;
+
+	ret = batadv_send_skb_packet(skb, neigh->if_incoming, neigh->addr);
+
+#ifdef CONFIG_BATMAN_ADV_BATMAN_V
+	hardif_neigh = batadv_hardif_neigh_get(neigh->if_incoming, neigh->addr);
+
+	if (hardif_neigh && ret != NET_XMIT_DROP)
+		hardif_neigh->bat_v.last_unicast_tx = jiffies;
+
+	batadv_hardif_neigh_put(hardif_neigh);
+#endif
+
+	return ret;
+}
+
+/**
+ * batadv_send_skb_to_orig() - Lookup next-hop and transmit skb.
+ * @skb: Packet to be transmitted.
+ * @orig_node: Final destination of the packet.
+ * @recv_if: Interface used when receiving the packet (can be NULL).
+ *
+ * Looks up the best next-hop towards the passed originator and passes the
+ * skb on for preparation of MAC header. If the packet originated from this
+ * host, NULL can be passed as recv_if and no interface alternating is
+ * attempted.
+ *
+ * Return: negative errno code on a failure, -EINPROGRESS if the skb is
+ * buffered for later transmit or the NET_XMIT status returned by the
+ * lower routine if the packet has been passed down.
+ */
+int batadv_send_skb_to_orig(struct sk_buff *skb,
+			    struct batadv_orig_node *orig_node,
+			    struct batadv_hard_iface *recv_if)
+{
+	struct batadv_priv *bat_priv = orig_node->bat_priv;
+	struct batadv_neigh_node *neigh_node;
+	int ret;
+
+	/* batadv_find_router() increases neigh_nodes refcount if found. */
+	neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
+	if (!neigh_node) {
+		ret = -EINVAL;
+		goto free_skb;
+	}
+
+	/* Check if the skb is too large to send in one piece and fragment
+	 * it if needed.
+	 */
+	if (atomic_read(&bat_priv->fragmentation) &&
+	    skb->len > neigh_node->if_incoming->net_dev->mtu) {
+		/* Fragment and send packet. */
+		ret = batadv_frag_send_packet(skb, orig_node, neigh_node);
+		/* skb was consumed */
+		skb = NULL;
+
+		goto put_neigh_node;
+	}
+
+	/* try to network code the packet, if it is received on an interface
+	 * (i.e. being forwarded). If the packet originates from this node or if
+	 * network coding fails, then send the packet as usual.
+	 */
+	if (recv_if && batadv_nc_skb_forward(skb, neigh_node))
+		ret = -EINPROGRESS;
+	else
+		ret = batadv_send_unicast_skb(skb, neigh_node);
+
+	/* skb was consumed */
+	skb = NULL;
+
+put_neigh_node:
+	batadv_neigh_node_put(neigh_node);
+free_skb:
+	kfree_skb(skb);
+
+	return ret;
+}
+
+/**
+ * batadv_send_skb_push_fill_unicast() - extend the buffer and initialize the
+ *  common fields for unicast packets
+ * @skb: the skb carrying the unicast header to initialize
+ * @hdr_size: amount of bytes to push at the beginning of the skb
+ * @orig_node: the destination node
+ *
+ * Return: false if the buffer extension was not possible or true otherwise.
+ */
+static bool
+batadv_send_skb_push_fill_unicast(struct sk_buff *skb, int hdr_size,
+				  struct batadv_orig_node *orig_node)
+{
+	struct batadv_unicast_packet *unicast_packet;
+	u8 ttvn = (u8)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->version = BATADV_COMPAT_VERSION;
+	/* batman packet type: unicast */
+	unicast_packet->packet_type = BATADV_UNICAST;
+	/* set unicast ttl */
+	unicast_packet->ttl = BATADV_TTL;
+	/* copy the destination for faster routing */
+	ether_addr_copy(unicast_packet->dest, orig_node->orig);
+	/* set the destination tt version number */
+	unicast_packet->ttvn = ttvn;
+
+	return true;
+}
+
+/**
+ * batadv_send_skb_prepare_unicast() - encapsulate an skb with a unicast header
+ * @skb: the skb containing the payload to encapsulate
+ * @orig_node: the destination node
+ *
+ * Return: false if the payload could not be encapsulated or true otherwise.
+ */
+static bool batadv_send_skb_prepare_unicast(struct sk_buff *skb,
+					    struct batadv_orig_node *orig_node)
+{
+	size_t uni_size = sizeof(struct batadv_unicast_packet);
+
+	return batadv_send_skb_push_fill_unicast(skb, uni_size, orig_node);
+}
+
+/**
+ * batadv_send_skb_prepare_unicast_4addr() - encapsulate an skb with a
+ *  unicast 4addr header
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: the skb containing the payload to encapsulate
+ * @orig: the destination node
+ * @packet_subtype: the unicast 4addr packet subtype to use
+ *
+ * Return: false if the payload could not be encapsulated or true otherwise.
+ */
+bool batadv_send_skb_prepare_unicast_4addr(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 *uc_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 uc_4addr_packet
+	 * is of type struct unicast_packet
+	 */
+	if (!batadv_send_skb_push_fill_unicast(skb, sizeof(*uc_4addr_packet),
+					       orig))
+		goto out;
+
+	uc_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
+	uc_4addr_packet->u.packet_type = BATADV_UNICAST_4ADDR;
+	ether_addr_copy(uc_4addr_packet->src, primary_if->net_dev->dev_addr);
+	uc_4addr_packet->subtype = packet_subtype;
+	uc_4addr_packet->reserved = 0;
+
+	ret = true;
+out:
+	batadv_hardif_put(primary_if);
+	return ret;
+}
+
+/**
+ * batadv_send_skb_unicast() - encapsulate and send an skb via 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 unicast 4addr packet subtype (only relevant for unicast
+ *  4addr packets)
+ * @orig_node: the originator to send the packet to
+ * @vid: the vid to be used to search the translation table
+ *
+ * Wrap the given skb into a batman-adv unicast or unicast-4addr header
+ * depending on whether BATADV_UNICAST or BATADV_UNICAST_4ADDR was supplied
+ * as packet_type. Then send this frame to the given orig_node.
+ *
+ * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
+ */
+int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
+			    struct sk_buff *skb, int packet_type,
+			    int packet_subtype,
+			    struct batadv_orig_node *orig_node,
+			    unsigned short vid)
+{
+	struct batadv_unicast_packet *unicast_packet;
+	struct ethhdr *ethhdr;
+	int ret = NET_XMIT_DROP;
+
+	if (!orig_node)
+		goto out;
+
+	switch (packet_type) {
+	case BATADV_UNICAST:
+		if (!batadv_send_skb_prepare_unicast(skb, orig_node))
+			goto out;
+		break;
+	case BATADV_UNICAST_4ADDR:
+		if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb,
+							   orig_node,
+							   packet_subtype))
+			goto out;
+		break;
+	default:
+		/* this function supports UNICAST and UNICAST_4ADDR only. It
+		 * should never be invoked with any other packet type
+		 */
+		goto out;
+	}
+
+	/* skb->data might have been reallocated by
+	 * batadv_send_skb_prepare_unicast{,_4addr}()
+	 */
+	ethhdr = eth_hdr(skb);
+	unicast_packet = (struct batadv_unicast_packet *)skb->data;
+
+	/* 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
+	 * than the current one
+	 */
+	if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest, vid))
+		unicast_packet->ttvn = unicast_packet->ttvn - 1;
+
+	ret = batadv_send_skb_to_orig(skb, orig_node, NULL);
+	 /* skb was consumed */
+	skb = NULL;
+
+out:
+	kfree_skb(skb);
+	return ret;
+}
+
+/**
+ * batadv_send_skb_via_tt_generic() - send an skb via TT lookup
+ * @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 unicast 4addr packet subtype (only relevant for unicast
+ *  4addr packets)
+ * @dst_hint: can be used to override the destination contained in the skb
+ * @vid: the vid to be used to search the translation table
+ *
+ * Look up the recipient node for the destination address in the ethernet
+ * header via the translation table. Wrap the given skb into a batman-adv
+ * unicast or unicast-4addr header depending on whether BATADV_UNICAST or
+ * BATADV_UNICAST_4ADDR was supplied as packet_type. Then send this frame
+ * to the according destination node.
+ *
+ * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
+ */
+int batadv_send_skb_via_tt_generic(struct batadv_priv *bat_priv,
+				   struct sk_buff *skb, int packet_type,
+				   int packet_subtype, u8 *dst_hint,
+				   unsigned short vid)
+{
+	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
+	struct batadv_orig_node *orig_node;
+	u8 *src, *dst;
+	int ret;
+
+	src = ethhdr->h_source;
+	dst = ethhdr->h_dest;
+
+	/* if we got an hint! let's send the packet to this client (if any) */
+	if (dst_hint) {
+		src = NULL;
+		dst = dst_hint;
+	}
+	orig_node = batadv_transtable_search(bat_priv, src, dst, vid);
+
+	ret = batadv_send_skb_unicast(bat_priv, skb, packet_type,
+				      packet_subtype, orig_node, vid);
+
+	batadv_orig_node_put(orig_node);
+
+	return ret;
+}
+
+/**
+ * batadv_send_skb_via_gw() - send an skb via gateway lookup
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: payload to send
+ * @vid: the vid to be used to search the translation table
+ *
+ * Look up the currently selected gateway. Wrap the given skb into a batman-adv
+ * unicast header and send this frame to this gateway node.
+ *
+ * Return: NET_XMIT_DROP in case of error or NET_XMIT_SUCCESS otherwise.
+ */
+int batadv_send_skb_via_gw(struct batadv_priv *bat_priv, struct sk_buff *skb,
+			   unsigned short vid)
+{
+	struct batadv_orig_node *orig_node;
+	int ret;
+
+	orig_node = batadv_gw_get_selected_orig(bat_priv);
+	ret = batadv_send_skb_unicast(bat_priv, skb, BATADV_UNICAST_4ADDR,
+				      BATADV_P_DATA, orig_node, vid);
+
+	batadv_orig_node_put(orig_node);
+
+	return ret;
+}
+
+/**
+ * batadv_forw_packet_free() - free a forwarding packet
+ * @forw_packet: The packet to free
+ * @dropped: whether the packet is freed because is dropped
+ *
+ * This frees a forwarding packet and releases any resources it might
+ * have claimed.
+ */
+void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet,
+			     bool dropped)
+{
+	if (dropped)
+		kfree_skb(forw_packet->skb);
+	else
+		consume_skb(forw_packet->skb);
+
+	batadv_hardif_put(forw_packet->if_incoming);
+	batadv_hardif_put(forw_packet->if_outgoing);
+	if (forw_packet->queue_left)
+		atomic_inc(forw_packet->queue_left);
+	kfree(forw_packet);
+}
+
+/**
+ * batadv_forw_packet_alloc() - allocate a forwarding packet
+ * @if_incoming: The (optional) if_incoming to be grabbed
+ * @if_outgoing: The (optional) if_outgoing to be grabbed
+ * @queue_left: The (optional) queue counter to decrease
+ * @bat_priv: The bat_priv for the mesh of this forw_packet
+ * @skb: The raw packet this forwarding packet shall contain
+ *
+ * Allocates a forwarding packet and tries to get a reference to the
+ * (optional) if_incoming, if_outgoing and queue_left. If queue_left
+ * is NULL then bat_priv is optional, too.
+ *
+ * Return: An allocated forwarding packet on success, NULL otherwise.
+ */
+struct batadv_forw_packet *
+batadv_forw_packet_alloc(struct batadv_hard_iface *if_incoming,
+			 struct batadv_hard_iface *if_outgoing,
+			 atomic_t *queue_left,
+			 struct batadv_priv *bat_priv,
+			 struct sk_buff *skb)
+{
+	struct batadv_forw_packet *forw_packet;
+	const char *qname;
+
+	if (queue_left && !batadv_atomic_dec_not_zero(queue_left)) {
+		qname = "unknown";
+
+		if (queue_left == &bat_priv->bcast_queue_left)
+			qname = "bcast";
+
+		if (queue_left == &bat_priv->batman_queue_left)
+			qname = "batman";
+
+		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+			   "%s queue is full\n", qname);
+
+		return NULL;
+	}
+
+	forw_packet = kmalloc(sizeof(*forw_packet), GFP_ATOMIC);
+	if (!forw_packet)
+		goto err;
+
+	if (if_incoming)
+		kref_get(&if_incoming->refcount);
+
+	if (if_outgoing)
+		kref_get(&if_outgoing->refcount);
+
+	INIT_HLIST_NODE(&forw_packet->list);
+	INIT_HLIST_NODE(&forw_packet->cleanup_list);
+	forw_packet->skb = skb;
+	forw_packet->queue_left = queue_left;
+	forw_packet->if_incoming = if_incoming;
+	forw_packet->if_outgoing = if_outgoing;
+	forw_packet->num_packets = 0;
+
+	return forw_packet;
+
+err:
+	if (queue_left)
+		atomic_inc(queue_left);
+
+	return NULL;
+}
+
+/**
+ * batadv_forw_packet_was_stolen() - check whether someone stole this packet
+ * @forw_packet: the forwarding packet to check
+ *
+ * This function checks whether the given forwarding packet was claimed by
+ * someone else for free().
+ *
+ * Return: True if someone stole it, false otherwise.
+ */
+static bool
+batadv_forw_packet_was_stolen(struct batadv_forw_packet *forw_packet)
+{
+	return !hlist_unhashed(&forw_packet->cleanup_list);
+}
+
+/**
+ * batadv_forw_packet_steal() - claim a forw_packet for free()
+ * @forw_packet: the forwarding packet to steal
+ * @lock: a key to the store to steal from (e.g. forw_{bat,bcast}_list_lock)
+ *
+ * This function tries to steal a specific forw_packet from global
+ * visibility for the purpose of getting it for free(). That means
+ * the caller is *not* allowed to requeue it afterwards.
+ *
+ * Return: True if stealing was successful. False if someone else stole it
+ * before us.
+ */
+bool batadv_forw_packet_steal(struct batadv_forw_packet *forw_packet,
+			      spinlock_t *lock)
+{
+	/* did purging routine steal it earlier? */
+	spin_lock_bh(lock);
+	if (batadv_forw_packet_was_stolen(forw_packet)) {
+		spin_unlock_bh(lock);
+		return false;
+	}
+
+	hlist_del_init(&forw_packet->list);
+
+	/* Just to spot misuse of this function */
+	hlist_add_fake(&forw_packet->cleanup_list);
+
+	spin_unlock_bh(lock);
+	return true;
+}
+
+/**
+ * batadv_forw_packet_list_steal() - claim a list of forward packets for free()
+ * @forw_list: the to be stolen forward packets
+ * @cleanup_list: a backup pointer, to be able to dispose the packet later
+ * @hard_iface: the interface to steal forward packets from
+ *
+ * This function claims responsibility to free any forw_packet queued on the
+ * given hard_iface. If hard_iface is NULL forwarding packets on all hard
+ * interfaces will be claimed.
+ *
+ * The packets are being moved from the forw_list to the cleanup_list. This
+ * makes it possible for already running threads to notice the claim.
+ */
+static void
+batadv_forw_packet_list_steal(struct hlist_head *forw_list,
+			      struct hlist_head *cleanup_list,
+			      const struct batadv_hard_iface *hard_iface)
+{
+	struct batadv_forw_packet *forw_packet;
+	struct hlist_node *safe_tmp_node;
+
+	hlist_for_each_entry_safe(forw_packet, safe_tmp_node,
+				  forw_list, list) {
+		/* if purge_outstanding_packets() was called with an argument
+		 * we delete only packets belonging to the given interface
+		 */
+		if (hard_iface &&
+		    forw_packet->if_incoming != hard_iface &&
+		    forw_packet->if_outgoing != hard_iface)
+			continue;
+
+		hlist_del(&forw_packet->list);
+		hlist_add_head(&forw_packet->cleanup_list, cleanup_list);
+	}
+}
+
+/**
+ * batadv_forw_packet_list_free() - free a list of forward packets
+ * @head: a list of to be freed forw_packets
+ *
+ * This function cancels the scheduling of any packet in the provided list,
+ * waits for any possibly running packet forwarding thread to finish and
+ * finally, safely frees this forward packet.
+ *
+ * This function might sleep.
+ */
+static void batadv_forw_packet_list_free(struct hlist_head *head)
+{
+	struct batadv_forw_packet *forw_packet;
+	struct hlist_node *safe_tmp_node;
+
+	hlist_for_each_entry_safe(forw_packet, safe_tmp_node, head,
+				  cleanup_list) {
+		cancel_delayed_work_sync(&forw_packet->delayed_work);
+
+		hlist_del(&forw_packet->cleanup_list);
+		batadv_forw_packet_free(forw_packet, true);
+	}
+}
+
+/**
+ * batadv_forw_packet_queue() - try to queue a forwarding packet
+ * @forw_packet: the forwarding packet to queue
+ * @lock: a key to the store (e.g. forw_{bat,bcast}_list_lock)
+ * @head: the shelve to queue it on (e.g. forw_{bat,bcast}_list)
+ * @send_time: timestamp (jiffies) when the packet is to be sent
+ *
+ * This function tries to (re)queue a forwarding packet. Requeuing
+ * is prevented if the according interface is shutting down
+ * (e.g. if batadv_forw_packet_list_steal() was called for this
+ * packet earlier).
+ *
+ * Calling batadv_forw_packet_queue() after a call to
+ * batadv_forw_packet_steal() is forbidden!
+ *
+ * Caller needs to ensure that forw_packet->delayed_work was initialized.
+ */
+static void batadv_forw_packet_queue(struct batadv_forw_packet *forw_packet,
+				     spinlock_t *lock, struct hlist_head *head,
+				     unsigned long send_time)
+{
+	spin_lock_bh(lock);
+
+	/* did purging routine steal it from us? */
+	if (batadv_forw_packet_was_stolen(forw_packet)) {
+		/* If you got it for free() without trouble, then
+		 * don't get back into the queue after stealing...
+		 */
+		WARN_ONCE(hlist_fake(&forw_packet->cleanup_list),
+			  "Requeuing after batadv_forw_packet_steal() not allowed!\n");
+
+		spin_unlock_bh(lock);
+		return;
+	}
+
+	hlist_del_init(&forw_packet->list);
+	hlist_add_head(&forw_packet->list, head);
+
+	queue_delayed_work(batadv_event_workqueue,
+			   &forw_packet->delayed_work,
+			   send_time - jiffies);
+	spin_unlock_bh(lock);
+}
+
+/**
+ * batadv_forw_packet_bcast_queue() - try to queue a broadcast packet
+ * @bat_priv: the bat priv with all the soft interface information
+ * @forw_packet: the forwarding packet to queue
+ * @send_time: timestamp (jiffies) when the packet is to be sent
+ *
+ * This function tries to (re)queue a broadcast packet.
+ *
+ * Caller needs to ensure that forw_packet->delayed_work was initialized.
+ */
+static void
+batadv_forw_packet_bcast_queue(struct batadv_priv *bat_priv,
+			       struct batadv_forw_packet *forw_packet,
+			       unsigned long send_time)
+{
+	batadv_forw_packet_queue(forw_packet, &bat_priv->forw_bcast_list_lock,
+				 &bat_priv->forw_bcast_list, send_time);
+}
+
+/**
+ * batadv_forw_packet_ogmv1_queue() - try to queue an OGMv1 packet
+ * @bat_priv: the bat priv with all the soft interface information
+ * @forw_packet: the forwarding packet to queue
+ * @send_time: timestamp (jiffies) when the packet is to be sent
+ *
+ * This function tries to (re)queue an OGMv1 packet.
+ *
+ * Caller needs to ensure that forw_packet->delayed_work was initialized.
+ */
+void batadv_forw_packet_ogmv1_queue(struct batadv_priv *bat_priv,
+				    struct batadv_forw_packet *forw_packet,
+				    unsigned long send_time)
+{
+	batadv_forw_packet_queue(forw_packet, &bat_priv->forw_bat_list_lock,
+				 &bat_priv->forw_bat_list, send_time);
+}
+
+/**
+ * batadv_forw_bcast_packet_to_list() - queue broadcast packet for transmissions
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: broadcast packet to add
+ * @delay: number of jiffies to wait before sending
+ * @own_packet: true if it is a self-generated broadcast packet
+ * @if_in: the interface where the packet was received on
+ * @if_out: the outgoing interface to queue on
+ *
+ * Adds a broadcast packet to the queue and sets up timers. Broadcast packets
+ * are sent multiple times to increase probability for being received.
+ *
+ * This call clones the given skb, hence the caller needs to take into
+ * account that the data segment of the original skb might not be
+ * modifiable anymore.
+ *
+ * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
+ */
+static int batadv_forw_bcast_packet_to_list(struct batadv_priv *bat_priv,
+					    struct sk_buff *skb,
+					    unsigned long delay,
+					    bool own_packet,
+					    struct batadv_hard_iface *if_in,
+					    struct batadv_hard_iface *if_out)
+{
+	struct batadv_forw_packet *forw_packet;
+	unsigned long send_time = jiffies;
+	struct sk_buff *newskb;
+
+	newskb = skb_clone(skb, GFP_ATOMIC);
+	if (!newskb)
+		goto err;
+
+	forw_packet = batadv_forw_packet_alloc(if_in, if_out,
+					       &bat_priv->bcast_queue_left,
+					       bat_priv, newskb);
+	if (!forw_packet)
+		goto err_packet_free;
+
+	forw_packet->own = own_packet;
+
+	INIT_DELAYED_WORK(&forw_packet->delayed_work,
+			  batadv_send_outstanding_bcast_packet);
+
+	send_time += delay ? delay : msecs_to_jiffies(5);
+
+	batadv_forw_packet_bcast_queue(bat_priv, forw_packet, send_time);
+	return NETDEV_TX_OK;
+
+err_packet_free:
+	kfree_skb(newskb);
+err:
+	return NETDEV_TX_BUSY;
+}
+
+/**
+ * batadv_forw_bcast_packet_if() - forward and queue a broadcast packet
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: broadcast packet to add
+ * @delay: number of jiffies to wait before sending
+ * @own_packet: true if it is a self-generated broadcast packet
+ * @if_in: the interface where the packet was received on
+ * @if_out: the outgoing interface to forward to
+ *
+ * Transmits a broadcast packet on the specified interface either immediately
+ * or if a delay is given after that. Furthermore, queues additional
+ * retransmissions if this interface is a wireless one.
+ *
+ * This call clones the given skb, hence the caller needs to take into
+ * account that the data segment of the original skb might not be
+ * modifiable anymore.
+ *
+ * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
+ */
+static int batadv_forw_bcast_packet_if(struct batadv_priv *bat_priv,
+				       struct sk_buff *skb,
+				       unsigned long delay,
+				       bool own_packet,
+				       struct batadv_hard_iface *if_in,
+				       struct batadv_hard_iface *if_out)
+{
+	unsigned int num_bcasts = if_out->num_bcasts;
+	struct sk_buff *newskb;
+	int ret = NETDEV_TX_OK;
+
+	if (!delay) {
+		newskb = skb_clone(skb, GFP_ATOMIC);
+		if (!newskb)
+			return NETDEV_TX_BUSY;
+
+		batadv_send_broadcast_skb(newskb, if_out);
+		num_bcasts--;
+	}
+
+	/* delayed broadcast or rebroadcasts? */
+	if (num_bcasts >= 1) {
+		BATADV_SKB_CB(skb)->num_bcasts = num_bcasts;
+
+		ret = batadv_forw_bcast_packet_to_list(bat_priv, skb, delay,
+						       own_packet, if_in,
+						       if_out);
+	}
+
+	return ret;
+}
+
+/**
+ * batadv_send_no_broadcast() - check whether (re)broadcast is necessary
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: broadcast packet to check
+ * @own_packet: true if it is a self-generated broadcast packet
+ * @if_out: the outgoing interface checked and considered for (re)broadcast
+ *
+ * Return: False if a packet needs to be (re)broadcasted on the given interface,
+ * true otherwise.
+ */
+static bool batadv_send_no_broadcast(struct batadv_priv *bat_priv,
+				     struct sk_buff *skb, bool own_packet,
+				     struct batadv_hard_iface *if_out)
+{
+	struct batadv_hardif_neigh_node *neigh_node = NULL;
+	struct batadv_bcast_packet *bcast_packet;
+	u8 *orig_neigh;
+	u8 *neigh_addr;
+	char *type;
+	int ret;
+
+	if (!own_packet) {
+		neigh_addr = eth_hdr(skb)->h_source;
+		neigh_node = batadv_hardif_neigh_get(if_out,
+						     neigh_addr);
+	}
+
+	bcast_packet = (struct batadv_bcast_packet *)skb->data;
+	orig_neigh = neigh_node ? neigh_node->orig : NULL;
+
+	ret = batadv_hardif_no_broadcast(if_out, bcast_packet->orig,
+					 orig_neigh);
+
+	batadv_hardif_neigh_put(neigh_node);
+
+	/* ok, may broadcast */
+	if (!ret)
+		return false;
+
+	/* no broadcast */
+	switch (ret) {
+	case BATADV_HARDIF_BCAST_NORECIPIENT:
+		type = "no neighbor";
+		break;
+	case BATADV_HARDIF_BCAST_DUPFWD:
+		type = "single neighbor is source";
+		break;
+	case BATADV_HARDIF_BCAST_DUPORIG:
+		type = "single neighbor is originator";
+		break;
+	default:
+		type = "unknown";
+	}
+
+	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+		   "BCAST packet from orig %pM on %s suppressed: %s\n",
+		   bcast_packet->orig,
+		   if_out->net_dev->name, type);
+
+	return true;
+}
+
+/**
+ * __batadv_forw_bcast_packet() - forward and queue a broadcast packet
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: broadcast packet to add
+ * @delay: number of jiffies to wait before sending
+ * @own_packet: true if it is a self-generated broadcast packet
+ *
+ * Transmits a broadcast packet either immediately or if a delay is given
+ * after that. Furthermore, queues additional retransmissions on wireless
+ * interfaces.
+ *
+ * This call clones the given skb, hence the caller needs to take into
+ * account that the data segment of the given skb might not be
+ * modifiable anymore.
+ *
+ * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
+ */
+static int __batadv_forw_bcast_packet(struct batadv_priv *bat_priv,
+				      struct sk_buff *skb,
+				      unsigned long delay,
+				      bool own_packet)
+{
+	struct batadv_hard_iface *hard_iface;
+	struct batadv_hard_iface *primary_if;
+	int ret = NETDEV_TX_OK;
+
+	primary_if = batadv_primary_if_get_selected(bat_priv);
+	if (!primary_if)
+		return NETDEV_TX_BUSY;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
+		if (hard_iface->soft_iface != bat_priv->soft_iface)
+			continue;
+
+		if (!kref_get_unless_zero(&hard_iface->refcount))
+			continue;
+
+		if (batadv_send_no_broadcast(bat_priv, skb, own_packet,
+					     hard_iface)) {
+			batadv_hardif_put(hard_iface);
+			continue;
+		}
+
+		ret = batadv_forw_bcast_packet_if(bat_priv, skb, delay,
+						  own_packet, primary_if,
+						  hard_iface);
+		batadv_hardif_put(hard_iface);
+
+		if (ret == NETDEV_TX_BUSY)
+			break;
+	}
+	rcu_read_unlock();
+
+	batadv_hardif_put(primary_if);
+	return ret;
+}
+
+/**
+ * batadv_forw_bcast_packet() - forward and queue a broadcast packet
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: broadcast packet to add
+ * @delay: number of jiffies to wait before sending
+ * @own_packet: true if it is a self-generated broadcast packet
+ *
+ * Transmits a broadcast packet either immediately or if a delay is given
+ * after that. Furthermore, queues additional retransmissions on wireless
+ * interfaces.
+ *
+ * Return: NETDEV_TX_OK on success and NETDEV_TX_BUSY on errors.
+ */
+int batadv_forw_bcast_packet(struct batadv_priv *bat_priv,
+			     struct sk_buff *skb,
+			     unsigned long delay,
+			     bool own_packet)
+{
+	return __batadv_forw_bcast_packet(bat_priv, skb, delay, own_packet);
+}
+
+/**
+ * batadv_send_bcast_packet() - send and queue a broadcast packet
+ * @bat_priv: the bat priv with all the soft interface information
+ * @skb: broadcast packet to add
+ * @delay: number of jiffies to wait before sending
+ * @own_packet: true if it is a self-generated broadcast packet
+ *
+ * Transmits a broadcast packet either immediately or if a delay is given
+ * after that. Furthermore, queues additional retransmissions on wireless
+ * interfaces.
+ *
+ * Consumes the provided skb.
+ */
+void batadv_send_bcast_packet(struct batadv_priv *bat_priv,
+			      struct sk_buff *skb,
+			      unsigned long delay,
+			      bool own_packet)
+{
+	__batadv_forw_bcast_packet(bat_priv, skb, delay, own_packet);
+	consume_skb(skb);
+}
+
+/**
+ * batadv_forw_packet_bcasts_left() - check if a retransmission is necessary
+ * @forw_packet: the forwarding packet to check
+ *
+ * Checks whether a given packet has any (re)transmissions left on the provided
+ * interface.
+ *
+ * hard_iface may be NULL: In that case the number of transmissions this skb had
+ * so far is compared with the maximum amount of retransmissions independent of
+ * any interface instead.
+ *
+ * Return: True if (re)transmissions are left, false otherwise.
+ */
+static bool
+batadv_forw_packet_bcasts_left(struct batadv_forw_packet *forw_packet)
+{
+	return BATADV_SKB_CB(forw_packet->skb)->num_bcasts;
+}
+
+/**
+ * batadv_forw_packet_bcasts_dec() - decrement retransmission counter of a
+ *  packet
+ * @forw_packet: the packet to decrease the counter for
+ */
+static void
+batadv_forw_packet_bcasts_dec(struct batadv_forw_packet *forw_packet)
+{
+	BATADV_SKB_CB(forw_packet->skb)->num_bcasts--;
+}
+
+/**
+ * batadv_forw_packet_is_rebroadcast() - check packet for previous transmissions
+ * @forw_packet: the packet to check
+ *
+ * Return: True if this packet was transmitted before, false otherwise.
+ */
+bool batadv_forw_packet_is_rebroadcast(struct batadv_forw_packet *forw_packet)
+{
+	unsigned char num_bcasts = BATADV_SKB_CB(forw_packet->skb)->num_bcasts;
+
+	return num_bcasts != forw_packet->if_outgoing->num_bcasts;
+}
+
+/**
+ * batadv_send_outstanding_bcast_packet() - transmit a queued broadcast packet
+ * @work: work queue item
+ *
+ * Transmits a queued broadcast packet and if necessary reschedules it.
+ */
+static void batadv_send_outstanding_bcast_packet(struct work_struct *work)
+{
+	unsigned long send_time = jiffies + msecs_to_jiffies(5);
+	struct batadv_forw_packet *forw_packet;
+	struct delayed_work *delayed_work;
+	struct batadv_priv *bat_priv;
+	struct sk_buff *skb1;
+	bool dropped = false;
+
+	delayed_work = to_delayed_work(work);
+	forw_packet = container_of(delayed_work, struct batadv_forw_packet,
+				   delayed_work);
+	bat_priv = netdev_priv(forw_packet->if_incoming->soft_iface);
+
+	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING) {
+		dropped = true;
+		goto out;
+	}
+
+	if (batadv_dat_drop_broadcast_packet(bat_priv, forw_packet)) {
+		dropped = true;
+		goto out;
+	}
+
+	/* send a copy of the saved skb */
+	skb1 = skb_clone(forw_packet->skb, GFP_ATOMIC);
+	if (!skb1)
+		goto out;
+
+	batadv_send_broadcast_skb(skb1, forw_packet->if_outgoing);
+	batadv_forw_packet_bcasts_dec(forw_packet);
+
+	if (batadv_forw_packet_bcasts_left(forw_packet)) {
+		batadv_forw_packet_bcast_queue(bat_priv, forw_packet,
+					       send_time);
+		return;
+	}
+
+out:
+	/* do we get something for free()? */
+	if (batadv_forw_packet_steal(forw_packet,
+				     &bat_priv->forw_bcast_list_lock))
+		batadv_forw_packet_free(forw_packet, dropped);
+}
+
+/**
+ * batadv_purge_outstanding_packets() - stop/purge scheduled bcast/OGMv1 packets
+ * @bat_priv: the bat priv with all the soft interface information
+ * @hard_iface: the hard interface to cancel and purge bcast/ogm packets on
+ *
+ * This method cancels and purges any broadcast and OGMv1 packet on the given
+ * hard_iface. If hard_iface is NULL, broadcast and OGMv1 packets on all hard
+ * interfaces will be canceled and purged.
+ *
+ * This function might sleep.
+ */
+void
+batadv_purge_outstanding_packets(struct batadv_priv *bat_priv,
+				 const struct batadv_hard_iface *hard_iface)
+{
+	struct hlist_head head = HLIST_HEAD_INIT;
+
+	if (hard_iface)
+		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+			   "%s(): %s\n",
+			   __func__, hard_iface->net_dev->name);
+	else
+		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
+			   "%s()\n", __func__);
+
+	/* claim bcast list for free() */
+	spin_lock_bh(&bat_priv->forw_bcast_list_lock);
+	batadv_forw_packet_list_steal(&bat_priv->forw_bcast_list, &head,
+				      hard_iface);
+	spin_unlock_bh(&bat_priv->forw_bcast_list_lock);
+
+	/* claim batman packet list for free() */
+	spin_lock_bh(&bat_priv->forw_bat_list_lock);
+	batadv_forw_packet_list_steal(&bat_priv->forw_bat_list, &head,
+				      hard_iface);
+	spin_unlock_bh(&bat_priv->forw_bat_list_lock);
+
+	/* then cancel or wait for packet workers to finish and free */
+	batadv_forw_packet_list_free(&head);
+}