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/* Copyright (C) 2007-2016 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 "send.h"
#include "main.h"
#include <linux/atomic.h>
#include <linux/byteorder/generic.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/fs.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/jiffies.h>
#include <linux/kernel.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.
*
* Return: NET_TX_DROP in case of error or the result of dev_queue_xmit(skb)
* otherwise
*/
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.
*
* a negative value cannot be returned because it could be interepreted
* as not consumed skb by callers of batadv_send_skb_to_orig.
*/
ret = dev_queue_xmit(skb);
if (ret < 0)
ret = NET_XMIT_DROP;
return ret;
send_skb_err:
kfree_skb(skb);
return NET_XMIT_DROP;
}
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);
}
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;
if (hardif_neigh)
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: -1 on failure (and the skb is not consumed), -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.
*
* If the returning value is not -1 the skb has been consumed.
*/
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 = -1;
/* batadv_find_router() increases neigh_nodes refcount if found. */
neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
if (!neigh_node)
goto out;
/* 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);
goto out;
}
/* 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);
out:
if (neigh_node)
batadv_neigh_node_put(neigh_node);
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);
}
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