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![Antonio Quartulli](/assets/img/avatar_default.png)
In commit a63fc6b75c
("rcu: Upgrade rcu_swap_protected() to
rcu_replace_pointer()") a new helper macro named rcu_replace_pointer() was
introduced to simplify code requiring to switch an rcu pointer to a new
value while extracting the old one.
Use rcu_replace_pointer() where appropriate to make code slimer.
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
831 lines
22 KiB
C
831 lines
22 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2009-2020 B.A.T.M.A.N. contributors:
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*
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* Marek Lindner
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*/
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#include "gateway_client.h"
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#include "main.h"
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#include <linux/atomic.h>
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#include <linux/byteorder/generic.h>
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#include <linux/errno.h>
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#include <linux/etherdevice.h>
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#include <linux/gfp.h>
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#include <linux/if_ether.h>
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#include <linux/if_vlan.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/kernel.h>
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#include <linux/kref.h>
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#include <linux/list.h>
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#include <linux/lockdep.h>
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#include <linux/netdevice.h>
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#include <linux/netlink.h>
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#include <linux/rculist.h>
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#include <linux/rcupdate.h>
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#include <linux/seq_file.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/stddef.h>
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#include <linux/udp.h>
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#include <net/sock.h>
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#include <uapi/linux/batadv_packet.h>
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#include <uapi/linux/batman_adv.h>
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#include "hard-interface.h"
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#include "log.h"
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#include "netlink.h"
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#include "originator.h"
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#include "routing.h"
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#include "soft-interface.h"
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#include "translation-table.h"
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/* These are the offsets of the "hw type" and "hw address length" in the dhcp
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* packet starting at the beginning of the dhcp header
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*/
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#define BATADV_DHCP_HTYPE_OFFSET 1
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#define BATADV_DHCP_HLEN_OFFSET 2
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/* Value of htype representing Ethernet */
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#define BATADV_DHCP_HTYPE_ETHERNET 0x01
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/* This is the offset of the "chaddr" field in the dhcp packet starting at the
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* beginning of the dhcp header
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*/
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#define BATADV_DHCP_CHADDR_OFFSET 28
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/**
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* batadv_gw_node_release() - release gw_node from lists and queue for free
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* after rcu grace period
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* @ref: kref pointer of the gw_node
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*/
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static void batadv_gw_node_release(struct kref *ref)
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{
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struct batadv_gw_node *gw_node;
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gw_node = container_of(ref, struct batadv_gw_node, refcount);
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batadv_orig_node_put(gw_node->orig_node);
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kfree_rcu(gw_node, rcu);
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}
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/**
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* batadv_gw_node_put() - decrement the gw_node refcounter and possibly release
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* it
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* @gw_node: gateway node to free
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*/
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void batadv_gw_node_put(struct batadv_gw_node *gw_node)
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{
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kref_put(&gw_node->refcount, batadv_gw_node_release);
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}
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/**
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* batadv_gw_get_selected_gw_node() - Get currently selected gateway
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* @bat_priv: the bat priv with all the soft interface information
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*
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* Return: selected gateway (with increased refcnt), NULL on errors
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*/
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struct batadv_gw_node *
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batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
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{
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struct batadv_gw_node *gw_node;
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rcu_read_lock();
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gw_node = rcu_dereference(bat_priv->gw.curr_gw);
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if (!gw_node)
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goto out;
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if (!kref_get_unless_zero(&gw_node->refcount))
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gw_node = NULL;
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out:
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rcu_read_unlock();
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return gw_node;
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}
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/**
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* batadv_gw_get_selected_orig() - Get originator of currently selected gateway
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* @bat_priv: the bat priv with all the soft interface information
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*
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* Return: orig_node of selected gateway (with increased refcnt), NULL on errors
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*/
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struct batadv_orig_node *
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batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
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{
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struct batadv_gw_node *gw_node;
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struct batadv_orig_node *orig_node = NULL;
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gw_node = batadv_gw_get_selected_gw_node(bat_priv);
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if (!gw_node)
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goto out;
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rcu_read_lock();
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orig_node = gw_node->orig_node;
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if (!orig_node)
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goto unlock;
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if (!kref_get_unless_zero(&orig_node->refcount))
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orig_node = NULL;
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unlock:
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rcu_read_unlock();
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out:
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if (gw_node)
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batadv_gw_node_put(gw_node);
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return orig_node;
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}
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static void batadv_gw_select(struct batadv_priv *bat_priv,
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struct batadv_gw_node *new_gw_node)
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{
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struct batadv_gw_node *curr_gw_node;
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spin_lock_bh(&bat_priv->gw.list_lock);
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if (new_gw_node)
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kref_get(&new_gw_node->refcount);
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curr_gw_node = rcu_replace_pointer(bat_priv->gw.curr_gw, new_gw_node,
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true);
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if (curr_gw_node)
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batadv_gw_node_put(curr_gw_node);
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spin_unlock_bh(&bat_priv->gw.list_lock);
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}
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/**
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* batadv_gw_reselect() - force a gateway reselection
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* @bat_priv: the bat priv with all the soft interface information
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*
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* Set a flag to remind the GW component to perform a new gateway reselection.
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* However this function does not ensure that the current gateway is going to be
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* deselected. The reselection mechanism may elect the same gateway once again.
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*
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* This means that invoking batadv_gw_reselect() does not guarantee a gateway
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* change and therefore a uevent is not necessarily expected.
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*/
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void batadv_gw_reselect(struct batadv_priv *bat_priv)
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{
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atomic_set(&bat_priv->gw.reselect, 1);
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}
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/**
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* batadv_gw_check_client_stop() - check if client mode has been switched off
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* @bat_priv: the bat priv with all the soft interface information
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*
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* This function assumes the caller has checked that the gw state *is actually
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* changing*. This function is not supposed to be called when there is no state
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* change.
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*/
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void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
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{
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struct batadv_gw_node *curr_gw;
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if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT)
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return;
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curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
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if (!curr_gw)
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return;
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/* deselect the current gateway so that next time that client mode is
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* enabled a proper GW_ADD event can be sent
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*/
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batadv_gw_select(bat_priv, NULL);
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/* if batman-adv is switching the gw client mode off and a gateway was
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* already selected, send a DEL uevent
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*/
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batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL, NULL);
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batadv_gw_node_put(curr_gw);
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}
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/**
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* batadv_gw_election() - Elect the best gateway
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* @bat_priv: the bat priv with all the soft interface information
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*/
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void batadv_gw_election(struct batadv_priv *bat_priv)
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{
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struct batadv_gw_node *curr_gw = NULL;
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struct batadv_gw_node *next_gw = NULL;
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struct batadv_neigh_node *router = NULL;
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struct batadv_neigh_ifinfo *router_ifinfo = NULL;
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char gw_addr[18] = { '\0' };
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if (atomic_read(&bat_priv->gw.mode) != BATADV_GW_MODE_CLIENT)
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goto out;
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if (!bat_priv->algo_ops->gw.get_best_gw_node)
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goto out;
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curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
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if (!batadv_atomic_dec_not_zero(&bat_priv->gw.reselect) && curr_gw)
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goto out;
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/* if gw.reselect is set to 1 it means that a previous call to
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* gw.is_eligible() said that we have a new best GW, therefore it can
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* now be picked from the list and selected
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*/
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next_gw = bat_priv->algo_ops->gw.get_best_gw_node(bat_priv);
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if (curr_gw == next_gw)
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goto out;
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if (next_gw) {
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sprintf(gw_addr, "%pM", next_gw->orig_node->orig);
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router = batadv_orig_router_get(next_gw->orig_node,
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BATADV_IF_DEFAULT);
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if (!router) {
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batadv_gw_reselect(bat_priv);
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goto out;
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}
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router_ifinfo = batadv_neigh_ifinfo_get(router,
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BATADV_IF_DEFAULT);
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if (!router_ifinfo) {
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batadv_gw_reselect(bat_priv);
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goto out;
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}
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}
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if (curr_gw && !next_gw) {
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batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
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"Removing selected gateway - no gateway in range\n");
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batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
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NULL);
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} else if (!curr_gw && next_gw) {
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batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
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"Adding route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
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next_gw->orig_node->orig,
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next_gw->bandwidth_down / 10,
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next_gw->bandwidth_down % 10,
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next_gw->bandwidth_up / 10,
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next_gw->bandwidth_up % 10,
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router_ifinfo->bat_iv.tq_avg);
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batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
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gw_addr);
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} else {
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batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
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"Changing route to gateway %pM (bandwidth: %u.%u/%u.%u MBit, tq: %i)\n",
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next_gw->orig_node->orig,
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next_gw->bandwidth_down / 10,
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next_gw->bandwidth_down % 10,
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next_gw->bandwidth_up / 10,
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next_gw->bandwidth_up % 10,
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router_ifinfo->bat_iv.tq_avg);
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batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
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gw_addr);
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}
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batadv_gw_select(bat_priv, next_gw);
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out:
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if (curr_gw)
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batadv_gw_node_put(curr_gw);
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if (next_gw)
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batadv_gw_node_put(next_gw);
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if (router)
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batadv_neigh_node_put(router);
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if (router_ifinfo)
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batadv_neigh_ifinfo_put(router_ifinfo);
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}
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/**
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* batadv_gw_check_election() - Elect orig node as best gateway when eligible
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* @bat_priv: the bat priv with all the soft interface information
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* @orig_node: orig node which is to be checked
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*/
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void batadv_gw_check_election(struct batadv_priv *bat_priv,
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struct batadv_orig_node *orig_node)
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{
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struct batadv_orig_node *curr_gw_orig;
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/* abort immediately if the routing algorithm does not support gateway
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* election
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*/
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if (!bat_priv->algo_ops->gw.is_eligible)
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return;
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curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
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if (!curr_gw_orig)
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goto reselect;
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/* this node already is the gateway */
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if (curr_gw_orig == orig_node)
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goto out;
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if (!bat_priv->algo_ops->gw.is_eligible(bat_priv, curr_gw_orig,
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orig_node))
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goto out;
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reselect:
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batadv_gw_reselect(bat_priv);
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out:
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if (curr_gw_orig)
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batadv_orig_node_put(curr_gw_orig);
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}
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/**
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* batadv_gw_node_add() - add gateway node to list of available gateways
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* @bat_priv: the bat priv with all the soft interface information
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* @orig_node: originator announcing gateway capabilities
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* @gateway: announced bandwidth information
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*
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* Has to be called with the appropriate locks being acquired
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* (gw.list_lock).
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*/
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static void batadv_gw_node_add(struct batadv_priv *bat_priv,
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struct batadv_orig_node *orig_node,
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struct batadv_tvlv_gateway_data *gateway)
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{
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struct batadv_gw_node *gw_node;
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lockdep_assert_held(&bat_priv->gw.list_lock);
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if (gateway->bandwidth_down == 0)
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return;
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gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
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if (!gw_node)
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return;
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kref_init(&gw_node->refcount);
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INIT_HLIST_NODE(&gw_node->list);
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kref_get(&orig_node->refcount);
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gw_node->orig_node = orig_node;
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gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
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gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
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kref_get(&gw_node->refcount);
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hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.gateway_list);
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bat_priv->gw.generation++;
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batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
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"Found new gateway %pM -> gw bandwidth: %u.%u/%u.%u MBit\n",
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orig_node->orig,
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ntohl(gateway->bandwidth_down) / 10,
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ntohl(gateway->bandwidth_down) % 10,
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ntohl(gateway->bandwidth_up) / 10,
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ntohl(gateway->bandwidth_up) % 10);
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/* don't return reference to new gw_node */
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batadv_gw_node_put(gw_node);
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}
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/**
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* batadv_gw_node_get() - retrieve gateway node from list of available gateways
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* @bat_priv: the bat priv with all the soft interface information
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* @orig_node: originator announcing gateway capabilities
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*
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* Return: gateway node if found or NULL otherwise.
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*/
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struct batadv_gw_node *batadv_gw_node_get(struct batadv_priv *bat_priv,
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struct batadv_orig_node *orig_node)
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{
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struct batadv_gw_node *gw_node_tmp, *gw_node = NULL;
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rcu_read_lock();
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hlist_for_each_entry_rcu(gw_node_tmp, &bat_priv->gw.gateway_list,
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list) {
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if (gw_node_tmp->orig_node != orig_node)
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continue;
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if (!kref_get_unless_zero(&gw_node_tmp->refcount))
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continue;
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gw_node = gw_node_tmp;
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break;
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}
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rcu_read_unlock();
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return gw_node;
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}
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|
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/**
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* batadv_gw_node_update() - update list of available gateways with changed
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* bandwidth information
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* @bat_priv: the bat priv with all the soft interface information
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* @orig_node: originator announcing gateway capabilities
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* @gateway: announced bandwidth information
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*/
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void batadv_gw_node_update(struct batadv_priv *bat_priv,
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struct batadv_orig_node *orig_node,
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struct batadv_tvlv_gateway_data *gateway)
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{
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struct batadv_gw_node *gw_node, *curr_gw = NULL;
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spin_lock_bh(&bat_priv->gw.list_lock);
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gw_node = batadv_gw_node_get(bat_priv, orig_node);
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if (!gw_node) {
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batadv_gw_node_add(bat_priv, orig_node, gateway);
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spin_unlock_bh(&bat_priv->gw.list_lock);
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goto out;
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}
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spin_unlock_bh(&bat_priv->gw.list_lock);
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if (gw_node->bandwidth_down == ntohl(gateway->bandwidth_down) &&
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gw_node->bandwidth_up == ntohl(gateway->bandwidth_up))
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goto out;
|
|
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batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
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"Gateway bandwidth of originator %pM changed from %u.%u/%u.%u MBit to %u.%u/%u.%u MBit\n",
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orig_node->orig,
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gw_node->bandwidth_down / 10,
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gw_node->bandwidth_down % 10,
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gw_node->bandwidth_up / 10,
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gw_node->bandwidth_up % 10,
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ntohl(gateway->bandwidth_down) / 10,
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ntohl(gateway->bandwidth_down) % 10,
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ntohl(gateway->bandwidth_up) / 10,
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ntohl(gateway->bandwidth_up) % 10);
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gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
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gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
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if (ntohl(gateway->bandwidth_down) == 0) {
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batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
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"Gateway %pM removed from gateway list\n",
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orig_node->orig);
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|
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/* Note: We don't need a NULL check here, since curr_gw never
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* gets dereferenced.
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*/
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spin_lock_bh(&bat_priv->gw.list_lock);
|
|
if (!hlist_unhashed(&gw_node->list)) {
|
|
hlist_del_init_rcu(&gw_node->list);
|
|
batadv_gw_node_put(gw_node);
|
|
bat_priv->gw.generation++;
|
|
}
|
|
spin_unlock_bh(&bat_priv->gw.list_lock);
|
|
|
|
curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
|
|
if (gw_node == curr_gw)
|
|
batadv_gw_reselect(bat_priv);
|
|
|
|
if (curr_gw)
|
|
batadv_gw_node_put(curr_gw);
|
|
}
|
|
|
|
out:
|
|
if (gw_node)
|
|
batadv_gw_node_put(gw_node);
|
|
}
|
|
|
|
/**
|
|
* batadv_gw_node_delete() - Remove orig_node from gateway list
|
|
* @bat_priv: the bat priv with all the soft interface information
|
|
* @orig_node: orig node which is currently in process of being removed
|
|
*/
|
|
void batadv_gw_node_delete(struct batadv_priv *bat_priv,
|
|
struct batadv_orig_node *orig_node)
|
|
{
|
|
struct batadv_tvlv_gateway_data gateway;
|
|
|
|
gateway.bandwidth_down = 0;
|
|
gateway.bandwidth_up = 0;
|
|
|
|
batadv_gw_node_update(bat_priv, orig_node, &gateway);
|
|
}
|
|
|
|
/**
|
|
* batadv_gw_node_free() - Free gateway information from soft interface
|
|
* @bat_priv: the bat priv with all the soft interface information
|
|
*/
|
|
void batadv_gw_node_free(struct batadv_priv *bat_priv)
|
|
{
|
|
struct batadv_gw_node *gw_node;
|
|
struct hlist_node *node_tmp;
|
|
|
|
spin_lock_bh(&bat_priv->gw.list_lock);
|
|
hlist_for_each_entry_safe(gw_node, node_tmp,
|
|
&bat_priv->gw.gateway_list, list) {
|
|
hlist_del_init_rcu(&gw_node->list);
|
|
batadv_gw_node_put(gw_node);
|
|
bat_priv->gw.generation++;
|
|
}
|
|
spin_unlock_bh(&bat_priv->gw.list_lock);
|
|
}
|
|
|
|
#ifdef CONFIG_BATMAN_ADV_DEBUGFS
|
|
|
|
/**
|
|
* batadv_gw_client_seq_print_text() - Print the gateway table in a seq file
|
|
* @seq: seq file to print on
|
|
* @offset: not used
|
|
*
|
|
* Return: always 0
|
|
*/
|
|
int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
|
|
{
|
|
struct net_device *net_dev = (struct net_device *)seq->private;
|
|
struct batadv_priv *bat_priv = netdev_priv(net_dev);
|
|
struct batadv_hard_iface *primary_if;
|
|
|
|
primary_if = batadv_seq_print_text_primary_if_get(seq);
|
|
if (!primary_if)
|
|
return 0;
|
|
|
|
seq_printf(seq, "[B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s %s)]\n",
|
|
BATADV_SOURCE_VERSION, primary_if->net_dev->name,
|
|
primary_if->net_dev->dev_addr, net_dev->name,
|
|
bat_priv->algo_ops->name);
|
|
|
|
batadv_hardif_put(primary_if);
|
|
|
|
if (!bat_priv->algo_ops->gw.print) {
|
|
seq_puts(seq,
|
|
"No printing function for this routing protocol\n");
|
|
return 0;
|
|
}
|
|
|
|
bat_priv->algo_ops->gw.print(bat_priv, seq);
|
|
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* batadv_gw_dump() - Dump gateways into a message
|
|
* @msg: Netlink message to dump into
|
|
* @cb: Control block containing additional options
|
|
*
|
|
* Return: Error code, or length of message
|
|
*/
|
|
int batadv_gw_dump(struct sk_buff *msg, struct netlink_callback *cb)
|
|
{
|
|
struct batadv_hard_iface *primary_if = NULL;
|
|
struct net *net = sock_net(cb->skb->sk);
|
|
struct net_device *soft_iface;
|
|
struct batadv_priv *bat_priv;
|
|
int ifindex;
|
|
int ret;
|
|
|
|
ifindex = batadv_netlink_get_ifindex(cb->nlh,
|
|
BATADV_ATTR_MESH_IFINDEX);
|
|
if (!ifindex)
|
|
return -EINVAL;
|
|
|
|
soft_iface = dev_get_by_index(net, ifindex);
|
|
if (!soft_iface || !batadv_softif_is_valid(soft_iface)) {
|
|
ret = -ENODEV;
|
|
goto out;
|
|
}
|
|
|
|
bat_priv = netdev_priv(soft_iface);
|
|
|
|
primary_if = batadv_primary_if_get_selected(bat_priv);
|
|
if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
|
|
ret = -ENOENT;
|
|
goto out;
|
|
}
|
|
|
|
if (!bat_priv->algo_ops->gw.dump) {
|
|
ret = -EOPNOTSUPP;
|
|
goto out;
|
|
}
|
|
|
|
bat_priv->algo_ops->gw.dump(msg, cb, bat_priv);
|
|
|
|
ret = msg->len;
|
|
|
|
out:
|
|
if (primary_if)
|
|
batadv_hardif_put(primary_if);
|
|
if (soft_iface)
|
|
dev_put(soft_iface);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* batadv_gw_dhcp_recipient_get() - check if a packet is a DHCP message
|
|
* @skb: the packet to check
|
|
* @header_len: a pointer to the batman-adv header size
|
|
* @chaddr: buffer where the client address will be stored. Valid
|
|
* only if the function returns BATADV_DHCP_TO_CLIENT
|
|
*
|
|
* This function may re-allocate the data buffer of the skb passed as argument.
|
|
*
|
|
* Return:
|
|
* - BATADV_DHCP_NO if the packet is not a dhcp message or if there was an error
|
|
* while parsing it
|
|
* - BATADV_DHCP_TO_SERVER if this is a message going to the DHCP server
|
|
* - BATADV_DHCP_TO_CLIENT if this is a message going to a DHCP client
|
|
*/
|
|
enum batadv_dhcp_recipient
|
|
batadv_gw_dhcp_recipient_get(struct sk_buff *skb, unsigned int *header_len,
|
|
u8 *chaddr)
|
|
{
|
|
enum batadv_dhcp_recipient ret = BATADV_DHCP_NO;
|
|
struct ethhdr *ethhdr;
|
|
struct iphdr *iphdr;
|
|
struct ipv6hdr *ipv6hdr;
|
|
struct udphdr *udphdr;
|
|
struct vlan_ethhdr *vhdr;
|
|
int chaddr_offset;
|
|
__be16 proto;
|
|
u8 *p;
|
|
|
|
/* check for ethernet header */
|
|
if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
|
|
return BATADV_DHCP_NO;
|
|
|
|
ethhdr = eth_hdr(skb);
|
|
proto = ethhdr->h_proto;
|
|
*header_len += ETH_HLEN;
|
|
|
|
/* check for initial vlan header */
|
|
if (proto == htons(ETH_P_8021Q)) {
|
|
if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
|
|
return BATADV_DHCP_NO;
|
|
|
|
vhdr = vlan_eth_hdr(skb);
|
|
proto = vhdr->h_vlan_encapsulated_proto;
|
|
*header_len += VLAN_HLEN;
|
|
}
|
|
|
|
/* check for ip header */
|
|
switch (proto) {
|
|
case htons(ETH_P_IP):
|
|
if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
|
|
return BATADV_DHCP_NO;
|
|
|
|
iphdr = (struct iphdr *)(skb->data + *header_len);
|
|
*header_len += iphdr->ihl * 4;
|
|
|
|
/* check for udp header */
|
|
if (iphdr->protocol != IPPROTO_UDP)
|
|
return BATADV_DHCP_NO;
|
|
|
|
break;
|
|
case htons(ETH_P_IPV6):
|
|
if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
|
|
return BATADV_DHCP_NO;
|
|
|
|
ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
|
|
*header_len += sizeof(*ipv6hdr);
|
|
|
|
/* check for udp header */
|
|
if (ipv6hdr->nexthdr != IPPROTO_UDP)
|
|
return BATADV_DHCP_NO;
|
|
|
|
break;
|
|
default:
|
|
return BATADV_DHCP_NO;
|
|
}
|
|
|
|
if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
|
|
return BATADV_DHCP_NO;
|
|
|
|
udphdr = (struct udphdr *)(skb->data + *header_len);
|
|
*header_len += sizeof(*udphdr);
|
|
|
|
/* check for bootp port */
|
|
switch (proto) {
|
|
case htons(ETH_P_IP):
|
|
if (udphdr->dest == htons(67))
|
|
ret = BATADV_DHCP_TO_SERVER;
|
|
else if (udphdr->source == htons(67))
|
|
ret = BATADV_DHCP_TO_CLIENT;
|
|
break;
|
|
case htons(ETH_P_IPV6):
|
|
if (udphdr->dest == htons(547))
|
|
ret = BATADV_DHCP_TO_SERVER;
|
|
else if (udphdr->source == htons(547))
|
|
ret = BATADV_DHCP_TO_CLIENT;
|
|
break;
|
|
}
|
|
|
|
chaddr_offset = *header_len + BATADV_DHCP_CHADDR_OFFSET;
|
|
/* store the client address if the message is going to a client */
|
|
if (ret == BATADV_DHCP_TO_CLIENT &&
|
|
pskb_may_pull(skb, chaddr_offset + ETH_ALEN)) {
|
|
/* check if the DHCP packet carries an Ethernet DHCP */
|
|
p = skb->data + *header_len + BATADV_DHCP_HTYPE_OFFSET;
|
|
if (*p != BATADV_DHCP_HTYPE_ETHERNET)
|
|
return BATADV_DHCP_NO;
|
|
|
|
/* check if the DHCP packet carries a valid Ethernet address */
|
|
p = skb->data + *header_len + BATADV_DHCP_HLEN_OFFSET;
|
|
if (*p != ETH_ALEN)
|
|
return BATADV_DHCP_NO;
|
|
|
|
ether_addr_copy(chaddr, skb->data + chaddr_offset);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* batadv_gw_out_of_range() - check if the dhcp request destination is the best
|
|
* gateway
|
|
* @bat_priv: the bat priv with all the soft interface information
|
|
* @skb: the outgoing packet
|
|
*
|
|
* Check if the skb is a DHCP request and if it is sent to the current best GW
|
|
* server. Due to topology changes it may be the case that the GW server
|
|
* previously selected is not the best one anymore.
|
|
*
|
|
* This call might reallocate skb data.
|
|
* Must be invoked only when the DHCP packet is going TO a DHCP SERVER.
|
|
*
|
|
* Return: true if the packet destination is unicast and it is not the best gw,
|
|
* false otherwise.
|
|
*/
|
|
bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
|
|
struct sk_buff *skb)
|
|
{
|
|
struct batadv_neigh_node *neigh_curr = NULL;
|
|
struct batadv_neigh_node *neigh_old = NULL;
|
|
struct batadv_orig_node *orig_dst_node = NULL;
|
|
struct batadv_gw_node *gw_node = NULL;
|
|
struct batadv_gw_node *curr_gw = NULL;
|
|
struct batadv_neigh_ifinfo *curr_ifinfo, *old_ifinfo;
|
|
struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
|
|
bool out_of_range = false;
|
|
u8 curr_tq_avg;
|
|
unsigned short vid;
|
|
|
|
vid = batadv_get_vid(skb, 0);
|
|
|
|
if (is_multicast_ether_addr(ethhdr->h_dest))
|
|
goto out;
|
|
|
|
orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
|
|
ethhdr->h_dest, vid);
|
|
if (!orig_dst_node)
|
|
goto out;
|
|
|
|
gw_node = batadv_gw_node_get(bat_priv, orig_dst_node);
|
|
if (!gw_node)
|
|
goto out;
|
|
|
|
switch (atomic_read(&bat_priv->gw.mode)) {
|
|
case BATADV_GW_MODE_SERVER:
|
|
/* If we are a GW then we are our best GW. We can artificially
|
|
* set the tq towards ourself as the maximum value
|
|
*/
|
|
curr_tq_avg = BATADV_TQ_MAX_VALUE;
|
|
break;
|
|
case BATADV_GW_MODE_CLIENT:
|
|
curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
|
|
if (!curr_gw)
|
|
goto out;
|
|
|
|
/* packet is going to our gateway */
|
|
if (curr_gw->orig_node == orig_dst_node)
|
|
goto out;
|
|
|
|
/* If the dhcp packet has been sent to a different gw,
|
|
* we have to evaluate whether the old gw is still
|
|
* reliable enough
|
|
*/
|
|
neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
|
|
NULL);
|
|
if (!neigh_curr)
|
|
goto out;
|
|
|
|
curr_ifinfo = batadv_neigh_ifinfo_get(neigh_curr,
|
|
BATADV_IF_DEFAULT);
|
|
if (!curr_ifinfo)
|
|
goto out;
|
|
|
|
curr_tq_avg = curr_ifinfo->bat_iv.tq_avg;
|
|
batadv_neigh_ifinfo_put(curr_ifinfo);
|
|
|
|
break;
|
|
case BATADV_GW_MODE_OFF:
|
|
default:
|
|
goto out;
|
|
}
|
|
|
|
neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
|
|
if (!neigh_old)
|
|
goto out;
|
|
|
|
old_ifinfo = batadv_neigh_ifinfo_get(neigh_old, BATADV_IF_DEFAULT);
|
|
if (!old_ifinfo)
|
|
goto out;
|
|
|
|
if ((curr_tq_avg - old_ifinfo->bat_iv.tq_avg) > BATADV_GW_THRESHOLD)
|
|
out_of_range = true;
|
|
batadv_neigh_ifinfo_put(old_ifinfo);
|
|
|
|
out:
|
|
if (orig_dst_node)
|
|
batadv_orig_node_put(orig_dst_node);
|
|
if (curr_gw)
|
|
batadv_gw_node_put(curr_gw);
|
|
if (gw_node)
|
|
batadv_gw_node_put(gw_node);
|
|
if (neigh_old)
|
|
batadv_neigh_node_put(neigh_old);
|
|
if (neigh_curr)
|
|
batadv_neigh_node_put(neigh_curr);
|
|
return out_of_range;
|
|
}
|