gateway_client.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) B.A.T.M.A.N. contributors:
 *
 * Marek Lindner
 */

#include "gateway_client.h"
#include "main.h"

#include <linux/atomic.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_ether.h>
#include <linux/if_vlan.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/netlink.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/sprintf.h>
#include <linux/stddef.h>
#include <linux/udp.h>
#include <net/sock.h>
#include <uapi/linux/batadv_packet.h>
#include <uapi/linux/batman_adv.h>

#include "hard-interface.h"
#include "log.h"
#include "netlink.h"
#include "originator.h"
#include "routing.h"
#include "soft-interface.h"
#include "translation-table.h"

/* These are the offsets of the "hw type" and "hw address length" in the dhcp
 * packet starting at the beginning of the dhcp header
 */
#define BATADV_DHCP_HTYPE_OFFSET …
#define BATADV_DHCP_HLEN_OFFSET …
/* Value of htype representing Ethernet */
#define BATADV_DHCP_HTYPE_ETHERNET …
/* This is the offset of the "chaddr" field in the dhcp packet starting at the
 * beginning of the dhcp header
 */
#define BATADV_DHCP_CHADDR_OFFSET …

/**
 * batadv_gw_node_release() - release gw_node from lists and queue for free
 *  after rcu grace period
 * @ref: kref pointer of the gw_node
 */
void batadv_gw_node_release(struct kref *ref)
{ … }

/**
 * batadv_gw_get_selected_gw_node() - Get currently selected gateway
 * @bat_priv: the bat priv with all the soft interface information
 *
 * Return: selected gateway (with increased refcnt), NULL on errors
 */
struct batadv_gw_node *
batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
{ … }

/**
 * batadv_gw_get_selected_orig() - Get originator of currently selected gateway
 * @bat_priv: the bat priv with all the soft interface information
 *
 * Return: orig_node of selected gateway (with increased refcnt), NULL on errors
 */
struct batadv_orig_node *
batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
{ … }

static void batadv_gw_select(struct batadv_priv *bat_priv,
			     struct batadv_gw_node *new_gw_node)
{ … }

/**
 * batadv_gw_reselect() - force a gateway reselection
 * @bat_priv: the bat priv with all the soft interface information
 *
 * Set a flag to remind the GW component to perform a new gateway reselection.
 * However this function does not ensure that the current gateway is going to be
 * deselected. The reselection mechanism may elect the same gateway once again.
 *
 * This means that invoking batadv_gw_reselect() does not guarantee a gateway
 * change and therefore a uevent is not necessarily expected.
 */
void batadv_gw_reselect(struct batadv_priv *bat_priv)
{ … }

/**
 * batadv_gw_check_client_stop() - check if client mode has been switched off
 * @bat_priv: the bat priv with all the soft interface information
 *
 * This function assumes the caller has checked that the gw state *is actually
 * changing*. This function is not supposed to be called when there is no state
 * change.
 */
void batadv_gw_check_client_stop(struct batadv_priv *bat_priv)
{ … }

/**
 * batadv_gw_election() - Elect the best gateway
 * @bat_priv: the bat priv with all the soft interface information
 */
void batadv_gw_election(struct batadv_priv *bat_priv)
{ … }

/**
 * batadv_gw_check_election() - Elect orig node as best gateway when eligible
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: orig node which is to be checked
 */
void batadv_gw_check_election(struct batadv_priv *bat_priv,
			      struct batadv_orig_node *orig_node)
{ … }

/**
 * batadv_gw_node_add() - add gateway node to list of available gateways
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: originator announcing gateway capabilities
 * @gateway: announced bandwidth information
 *
 * Has to be called with the appropriate locks being acquired
 * (gw.list_lock).
 */
static void batadv_gw_node_add(struct batadv_priv *bat_priv,
			       struct batadv_orig_node *orig_node,
			       struct batadv_tvlv_gateway_data *gateway)
{ … }

/**
 * batadv_gw_node_get() - retrieve gateway node from list of available gateways
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: originator announcing gateway capabilities
 *
 * Return: gateway node if found or NULL otherwise.
 */
struct batadv_gw_node *batadv_gw_node_get(struct batadv_priv *bat_priv,
					  struct batadv_orig_node *orig_node)
{ … }

/**
 * batadv_gw_node_update() - update list of available gateways with changed
 *  bandwidth information
 * @bat_priv: the bat priv with all the soft interface information
 * @orig_node: originator announcing gateway capabilities
 * @gateway: announced bandwidth information
 */
void batadv_gw_node_update(struct batadv_priv *bat_priv,
			   struct batadv_orig_node *orig_node,
			   struct batadv_tvlv_gateway_data *gateway)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }
linux/net/batman-adv/gateway_client.c
