1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (C) B.A.T.M.A.N. contributors:
3 *
4 * Marek Lindner, Simon Wunderlich
5 */
6
7#include "main.h"
8
9#include <linux/errno.h>
10#include <linux/list.h>
11#include <linux/moduleparam.h>
12#include <linux/netlink.h>
13#include <linux/printk.h>
14#include <linux/skbuff.h>
15#include <linux/stddef.h>
16#include <linux/string.h>
17#include <net/genetlink.h>
18#include <net/netlink.h>
19#include <uapi/linux/batman_adv.h>
20
21#include "bat_algo.h"
22#include "netlink.h"
23
24char batadv_routing_algo[20] = "BATMAN_IV";
25static struct hlist_head batadv_algo_list;
26
27/**
28 * batadv_algo_init() - Initialize batman-adv algorithm management data
29 *  structures
30 */
31void batadv_algo_init(void)
32{
33	INIT_HLIST_HEAD(&batadv_algo_list);
34}
35
36/**
37 * batadv_algo_get() - Search for algorithm with specific name
38 * @name: algorithm name to find
39 *
40 * Return: Pointer to batadv_algo_ops on success, NULL otherwise
41 */
42struct batadv_algo_ops *batadv_algo_get(const char *name)
43{
44	struct batadv_algo_ops *bat_algo_ops = NULL, *bat_algo_ops_tmp;
45
46	hlist_for_each_entry(bat_algo_ops_tmp, &batadv_algo_list, list) {
47		if (strcmp(bat_algo_ops_tmp->name, name) != 0)
48			continue;
49
50		bat_algo_ops = bat_algo_ops_tmp;
51		break;
52	}
53
54	return bat_algo_ops;
55}
56
57/**
58 * batadv_algo_register() - Register callbacks for a mesh algorithm
59 * @bat_algo_ops: mesh algorithm callbacks to add
60 *
61 * Return: 0 on success or negative error number in case of failure
62 */
63int batadv_algo_register(struct batadv_algo_ops *bat_algo_ops)
64{
65	struct batadv_algo_ops *bat_algo_ops_tmp;
66
67	bat_algo_ops_tmp = batadv_algo_get(bat_algo_ops->name);
68	if (bat_algo_ops_tmp) {
69		pr_info("Trying to register already registered routing algorithm: %s\n",
70			bat_algo_ops->name);
71		return -EEXIST;
72	}
73
74	/* all algorithms must implement all ops (for now) */
75	if (!bat_algo_ops->iface.enable ||
76	    !bat_algo_ops->iface.disable ||
77	    !bat_algo_ops->iface.update_mac ||
78	    !bat_algo_ops->iface.primary_set ||
79	    !bat_algo_ops->neigh.cmp ||
80	    !bat_algo_ops->neigh.is_similar_or_better) {
81		pr_info("Routing algo '%s' does not implement required ops\n",
82			bat_algo_ops->name);
83		return -EINVAL;
84	}
85
86	INIT_HLIST_NODE(&bat_algo_ops->list);
87	hlist_add_head(&bat_algo_ops->list, &batadv_algo_list);
88
89	return 0;
90}
91
92/**
93 * batadv_algo_select() - Select algorithm of soft interface
94 * @bat_priv: the bat priv with all the soft interface information
95 * @name: name of the algorithm to select
96 *
97 * The algorithm callbacks for the soft interface will be set when the algorithm
98 * with the correct name was found. Any previous selected algorithm will not be
99 * deinitialized and the new selected algorithm will also not be initialized.
100 * It is therefore not allowed to call batadv_algo_select outside the creation
101 * function of the soft interface.
102 *
103 * Return: 0 on success or negative error number in case of failure
104 */
105int batadv_algo_select(struct batadv_priv *bat_priv, const char *name)
106{
107	struct batadv_algo_ops *bat_algo_ops;
108
109	bat_algo_ops = batadv_algo_get(name);
110	if (!bat_algo_ops)
111		return -EINVAL;
112
113	bat_priv->algo_ops = bat_algo_ops;
114
115	return 0;
116}
117
118static int batadv_param_set_ra(const char *val, const struct kernel_param *kp)
119{
120	struct batadv_algo_ops *bat_algo_ops;
121	char *algo_name = (char *)val;
122	size_t name_len = strlen(algo_name);
123
124	if (name_len > 0 && algo_name[name_len - 1] == '\n')
125		algo_name[name_len - 1] = '\0';
126
127	bat_algo_ops = batadv_algo_get(algo_name);
128	if (!bat_algo_ops) {
129		pr_err("Routing algorithm '%s' is not supported\n", algo_name);
130		return -EINVAL;
131	}
132
133	return param_set_copystring(algo_name, kp);
134}
135
136static const struct kernel_param_ops batadv_param_ops_ra = {
137	.set = batadv_param_set_ra,
138	.get = param_get_string,
139};
140
141static struct kparam_string batadv_param_string_ra = {
142	.maxlen = sizeof(batadv_routing_algo),
143	.string = batadv_routing_algo,
144};
145
146module_param_cb(routing_algo, &batadv_param_ops_ra, &batadv_param_string_ra,
147		0644);
148
149/**
150 * batadv_algo_dump_entry() - fill in information about one supported routing
151 *  algorithm
152 * @msg: netlink message to be sent back
153 * @portid: Port to reply to
154 * @seq: Sequence number of message
155 * @bat_algo_ops: Algorithm to be dumped
156 *
157 * Return: Error number, or 0 on success
158 */
159static int batadv_algo_dump_entry(struct sk_buff *msg, u32 portid, u32 seq,
160				  struct batadv_algo_ops *bat_algo_ops)
161{
162	void *hdr;
163
164	hdr = genlmsg_put(msg, portid, seq, &batadv_netlink_family,
165			  NLM_F_MULTI, BATADV_CMD_GET_ROUTING_ALGOS);
166	if (!hdr)
167		return -EMSGSIZE;
168
169	if (nla_put_string(msg, BATADV_ATTR_ALGO_NAME, bat_algo_ops->name))
170		goto nla_put_failure;
171
172	genlmsg_end(msg, hdr);
173	return 0;
174
175 nla_put_failure:
176	genlmsg_cancel(msg, hdr);
177	return -EMSGSIZE;
178}
179
180/**
181 * batadv_algo_dump() - fill in information about supported routing
182 *  algorithms
183 * @msg: netlink message to be sent back
184 * @cb: Parameters to the netlink request
185 *
186 * Return: Length of reply message.
187 */
188int batadv_algo_dump(struct sk_buff *msg, struct netlink_callback *cb)
189{
190	int portid = NETLINK_CB(cb->skb).portid;
191	struct batadv_algo_ops *bat_algo_ops;
192	int skip = cb->args[0];
193	int i = 0;
194
195	hlist_for_each_entry(bat_algo_ops, &batadv_algo_list, list) {
196		if (i++ < skip)
197			continue;
198
199		if (batadv_algo_dump_entry(msg, portid, cb->nlh->nlmsg_seq,
200					   bat_algo_ops)) {
201			i--;
202			break;
203		}
204	}
205
206	cb->args[0] = i;
207
208	return msg->len;
209}
210