linux/net/batman-adv/gateway_common.c

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

#include "gateway_common.h"
#include "main.h"

#include <linux/atomic.h>
#include <linux/byteorder/generic.h>
#include <linux/kstrtox.h>
#include <linux/limits.h>
#include <linux/math64.h>
#include <linux/netdevice.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <uapi/linux/batadv_packet.h>
#include <uapi/linux/batman_adv.h>

#include "gateway_client.h"
#include "log.h"
#include "tvlv.h"

/**
 * batadv_parse_throughput() - parse supplied string buffer to extract
 *  throughput information
 * @net_dev: the soft interface net device
 * @buff: string buffer to parse
 * @description: text shown when throughput string cannot be parsed
 * @throughput: pointer holding the returned throughput information
 *
 * Return: false on parse error and true otherwise.
 */
bool batadv_parse_throughput(struct net_device *net_dev, char *buff,
			     const char *description, u32 *throughput)
{
	enum batadv_bandwidth_units bw_unit_type = BATADV_BW_UNIT_KBIT;
	u64 lthroughput;
	char *tmp_ptr;
	int ret;

	if (strlen(buff) > 4) {
		tmp_ptr = buff + strlen(buff) - 4;

		if (strncasecmp(tmp_ptr, "mbit", 4) == 0)
			bw_unit_type = BATADV_BW_UNIT_MBIT;

		if (strncasecmp(tmp_ptr, "kbit", 4) == 0 ||
		    bw_unit_type == BATADV_BW_UNIT_MBIT)
			*tmp_ptr = '\0';
	}

	ret = kstrtou64(buff, 10, &lthroughput);
	if (ret) {
		batadv_err(net_dev,
			   "Invalid throughput speed for %s: %s\n",
			   description, buff);
		return false;
	}

	switch (bw_unit_type) {
	case BATADV_BW_UNIT_MBIT:
		/* prevent overflow */
		if (U64_MAX / 10 < lthroughput) {
			batadv_err(net_dev,
				   "Throughput speed for %s too large: %s\n",
				   description, buff);
			return false;
		}

		lthroughput *= 10;
		break;
	case BATADV_BW_UNIT_KBIT:
	default:
		lthroughput = div_u64(lthroughput, 100);
		break;
	}

	if (lthroughput > U32_MAX) {
		batadv_err(net_dev,
			   "Throughput speed for %s too large: %s\n",
			   description, buff);
		return false;
	}

	*throughput = lthroughput;

	return true;
}

/**
 * batadv_gw_tvlv_container_update() - update the gw tvlv container after
 *  gateway setting change
 * @bat_priv: the bat priv with all the soft interface information
 */
void batadv_gw_tvlv_container_update(struct batadv_priv *bat_priv)
{
	struct batadv_tvlv_gateway_data gw;
	u32 down, up;
	char gw_mode;

	gw_mode = atomic_read(&bat_priv->gw.mode);

	switch (gw_mode) {
	case BATADV_GW_MODE_OFF:
	case BATADV_GW_MODE_CLIENT:
		batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_GW, 1);
		break;
	case BATADV_GW_MODE_SERVER:
		down = atomic_read(&bat_priv->gw.bandwidth_down);
		up = atomic_read(&bat_priv->gw.bandwidth_up);
		gw.bandwidth_down = htonl(down);
		gw.bandwidth_up = htonl(up);
		batadv_tvlv_container_register(bat_priv, BATADV_TVLV_GW, 1,
					       &gw, sizeof(gw));
		break;
	}
}

/**
 * batadv_gw_tvlv_ogm_handler_v1() - process incoming gateway tvlv container
 * @bat_priv: the bat priv with all the soft interface information
 * @orig: the orig_node of the ogm
 * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
 * @tvlv_value: tvlv buffer containing the gateway data
 * @tvlv_value_len: tvlv buffer length
 */
static void batadv_gw_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
					  struct batadv_orig_node *orig,
					  u8 flags,
					  void *tvlv_value, u16 tvlv_value_len)
{
	struct batadv_tvlv_gateway_data gateway, *gateway_ptr;

	/* only fetch the tvlv value if the handler wasn't called via the
	 * CIFNOTFND flag and if there is data to fetch
	 */
	if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND ||
	    tvlv_value_len < sizeof(gateway)) {
		gateway.bandwidth_down = 0;
		gateway.bandwidth_up = 0;
	} else {
		gateway_ptr = tvlv_value;
		gateway.bandwidth_down = gateway_ptr->bandwidth_down;
		gateway.bandwidth_up = gateway_ptr->bandwidth_up;
		if (gateway.bandwidth_down == 0 ||
		    gateway.bandwidth_up == 0) {
			gateway.bandwidth_down = 0;
			gateway.bandwidth_up = 0;
		}
	}

	batadv_gw_node_update(bat_priv, orig, &gateway);

	/* restart gateway selection */
	if (gateway.bandwidth_down != 0 &&
	    atomic_read(&bat_priv->gw.mode) == BATADV_GW_MODE_CLIENT)
		batadv_gw_check_election(bat_priv, orig);
}

/**
 * batadv_gw_init() - initialise the gateway handling internals
 * @bat_priv: the bat priv with all the soft interface information
 */
void batadv_gw_init(struct batadv_priv *bat_priv)
{
	if (bat_priv->algo_ops->gw.init_sel_class)
		bat_priv->algo_ops->gw.init_sel_class(bat_priv);
	else
		atomic_set(&bat_priv->gw.sel_class, 1);

	batadv_tvlv_handler_register(bat_priv, batadv_gw_tvlv_ogm_handler_v1,
				     NULL, NULL, BATADV_TVLV_GW, 1,
				     BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
}

/**
 * batadv_gw_free() - free the gateway handling internals
 * @bat_priv: the bat priv with all the soft interface information
 */
void batadv_gw_free(struct batadv_priv *bat_priv)
{
	batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_GW, 1);
	batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_GW, 1);
}