// SPDX-License-Identifier: GPL-2.0

  /* Copyright (C) 2007-2019  B.A.T.M.A.N. contributors:

   *
   * Marek Lindner, Simon Wunderlich

   */
  
  #include "main.h"
  
  #include <linux/errno.h>
  #include <linux/list.h>
  #include <linux/moduleparam.h>

  #include <linux/netlink.h>

  #include <linux/printk.h>
  #include <linux/seq_file.h>

  #include <linux/skbuff.h>

  #include <linux/stddef.h>
  #include <linux/string.h>

  #include <net/genetlink.h>
  #include <net/netlink.h>
  #include <uapi/linux/batman_adv.h>

  
  #include "bat_algo.h"

  #include "netlink.h"

  
  char batadv_routing_algo[20] = "BATMAN_IV";
  static struct hlist_head batadv_algo_list;
  
  /**

   * batadv_algo_init() - Initialize batman-adv algorithm management data
   *  structures

   */
  void batadv_algo_init(void)
  {
  	INIT_HLIST_HEAD(&batadv_algo_list);
  }
  
  static struct batadv_algo_ops *batadv_algo_get(char *name)
  {
  	struct batadv_algo_ops *bat_algo_ops = NULL, *bat_algo_ops_tmp;
  
  	hlist_for_each_entry(bat_algo_ops_tmp, &batadv_algo_list, list) {
  		if (strcmp(bat_algo_ops_tmp->name, name) != 0)
  			continue;
  
  		bat_algo_ops = bat_algo_ops_tmp;
  		break;
  	}
  
  	return bat_algo_ops;
  }

  /**
   * batadv_algo_register() - Register callbacks for a mesh algorithm
   * @bat_algo_ops: mesh algorithm callbacks to add
   *
   * Return: 0 on success or negative error number in case of failure
   */

  int batadv_algo_register(struct batadv_algo_ops *bat_algo_ops)
  {
  	struct batadv_algo_ops *bat_algo_ops_tmp;
  
  	bat_algo_ops_tmp = batadv_algo_get(bat_algo_ops->name);
  	if (bat_algo_ops_tmp) {
  		pr_info("Trying to register already registered routing algorithm: %s
  ",
  			bat_algo_ops->name);
  		return -EEXIST;
  	}
  
  	/* all algorithms must implement all ops (for now) */

  	if (!bat_algo_ops->iface.enable ||
  	    !bat_algo_ops->iface.disable ||
  	    !bat_algo_ops->iface.update_mac ||
  	    !bat_algo_ops->iface.primary_set ||
  	    !bat_algo_ops->neigh.cmp ||
  	    !bat_algo_ops->neigh.is_similar_or_better) {

  		pr_info("Routing algo '%s' does not implement required ops
  ",
  			bat_algo_ops->name);
  		return -EINVAL;
  	}
  
  	INIT_HLIST_NODE(&bat_algo_ops->list);
  	hlist_add_head(&bat_algo_ops->list, &batadv_algo_list);
  
  	return 0;
  }

  /**
   * batadv_algo_select() - Select algorithm of soft interface
   * @bat_priv: the bat priv with all the soft interface information
   * @name: name of the algorithm to select
   *
   * The algorithm callbacks for the soft interface will be set when the algorithm
   * with the correct name was found. Any previous selected algorithm will not be
   * deinitialized and the new selected algorithm will also not be initialized.
   * It is therefore not allowed to call batadv_algo_select outside the creation
   * function of the soft interface.
   *
   * Return: 0 on success or negative error number in case of failure
   */

  int batadv_algo_select(struct batadv_priv *bat_priv, char *name)
  {
  	struct batadv_algo_ops *bat_algo_ops;
  
  	bat_algo_ops = batadv_algo_get(name);
  	if (!bat_algo_ops)
  		return -EINVAL;

  	bat_priv->algo_ops = bat_algo_ops;

  
  	return 0;
  }

  #ifdef CONFIG_BATMAN_ADV_DEBUGFS

  
  /**
   * batadv_algo_seq_print_text() - Print the supported algorithms in a seq file
   * @seq: seq file to print on
   * @offset: not used
   *
   * Return: always 0
   */

  int batadv_algo_seq_print_text(struct seq_file *seq, void *offset)
  {
  	struct batadv_algo_ops *bat_algo_ops;
  
  	seq_puts(seq, "Available routing algorithms:
  ");
  
  	hlist_for_each_entry(bat_algo_ops, &batadv_algo_list, list) {
  		seq_printf(seq, " * %s
  ", bat_algo_ops->name);
  	}
  
  	return 0;
  }

  #endif

  
  static int batadv_param_set_ra(const char *val, const struct kernel_param *kp)
  {
  	struct batadv_algo_ops *bat_algo_ops;
  	char *algo_name = (char *)val;
  	size_t name_len = strlen(algo_name);
  
  	if (name_len > 0 && algo_name[name_len - 1] == '
  ')
  		algo_name[name_len - 1] = '\0';
  
  	bat_algo_ops = batadv_algo_get(algo_name);
  	if (!bat_algo_ops) {
  		pr_err("Routing algorithm '%s' is not supported
  ", algo_name);
  		return -EINVAL;
  	}
  
  	return param_set_copystring(algo_name, kp);
  }
  
  static const struct kernel_param_ops batadv_param_ops_ra = {
  	.set = batadv_param_set_ra,
  	.get = param_get_string,
  };
  
  static struct kparam_string batadv_param_string_ra = {
  	.maxlen = sizeof(batadv_routing_algo),
  	.string = batadv_routing_algo,
  };
  
  module_param_cb(routing_algo, &batadv_param_ops_ra, &batadv_param_string_ra,
  		0644);

  
  /**

   * batadv_algo_dump_entry() - fill in information about one supported routing

   *  algorithm
   * @msg: netlink message to be sent back
   * @portid: Port to reply to
   * @seq: Sequence number of message
   * @bat_algo_ops: Algorithm to be dumped
   *
   * Return: Error number, or 0 on success
   */
  static int batadv_algo_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
  				  struct batadv_algo_ops *bat_algo_ops)
  {
  	void *hdr;
  
  	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family,
  			  NLM_F_MULTI, BATADV_CMD_GET_ROUTING_ALGOS);
  	if (!hdr)
  		return -EMSGSIZE;
  
  	if (nla_put_string(msg, BATADV_ATTR_ALGO_NAME, bat_algo_ops->name))
  		goto nla_put_failure;
  
  	genlmsg_end(msg, hdr);
  	return 0;
  
   nla_put_failure:
  	genlmsg_cancel(msg, hdr);
  	return -EMSGSIZE;
  }
  
  /**

   * batadv_algo_dump() - fill in information about supported routing

   *  algorithms
   * @msg: netlink message to be sent back
   * @cb: Parameters to the netlink request
   *
   * Return: Length of reply message.
   */
  int batadv_algo_dump(struct sk_buff *msg, struct netlink_callback *cb)
  {
  	int portid = NETLINK_CB(cb->skb).portid;
  	struct batadv_algo_ops *bat_algo_ops;
  	int skip = cb->args[0];
  	int i = 0;
  
  	hlist_for_each_entry(bat_algo_ops, &batadv_algo_list, list) {
  		if (i++ < skip)
  			continue;
  
  		if (batadv_algo_dump_entry(msg, portid, cb->nlh->nlmsg_seq,
  					   bat_algo_ops)) {
  			i--;
  			break;
  		}
  	}
  
  	cb->args[0] = i;
  
  	return msg->len;
  }