path: root/net/batman-adv/send.c

// 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 t