linux-stable/net/batman-adv/bat_algo.c
Sven Eckelmann a5ad457eea batman-adv: Allow selection of routing algorithm over rtnetlink
A batadv net_device is associated to a B.A.T.M.A.N. routing algorithm. This
algorithm has to be selected before the interface is initialized and cannot
be changed after that. The only way to select this algorithm was a module
parameter which specifies the default algorithm used during the creation of
the net_device.

This module parameter is writeable over
/sys/module/batman_adv/parameters/routing_algo and thus allows switching of
the routing algorithm:

1. change routing_algo parameter
2. create new batadv net_device

But this is not race free because another process can be scheduled between
1 + 2 and in that time frame change the routing_algo parameter again.

It is much cleaner to directly provide this information inside the
rtnetlink's RTM_NEWLINK message. The two processes would be (in regards of
the creation parameter of their batadv interfaces) be isolated. This also
eases the integration of batadv devices inside tools like network-manager
or systemd-networkd which are not expecting to operate on /sys before a new
net_device is created.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2020-12-04 08:40:52 +01:00

233 lines
5.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2007-2020 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);
}
/**
* batadv_algo_get() - Search for algorithm with specific name
* @name: algorithm name to find
*
* Return: Pointer to batadv_algo_ops on success, NULL otherwise
*/
struct batadv_algo_ops *batadv_algo_get(const 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\n",
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\n",
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, const 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:\n");
hlist_for_each_entry(bat_algo_ops, &batadv_algo_list, list) {
seq_printf(seq, " * %s\n", 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] == '\n')
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\n", 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;
}