1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/l3mdev/l3mdev.c - L3 master device implementation
4 * Copyright (c) 2015 Cumulus Networks
5 * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
6 */
7
8#include <linux/netdevice.h>
9#include <net/fib_rules.h>
10#include <net/l3mdev.h>
11
12static DEFINE_SPINLOCK(l3mdev_lock);
13
14struct l3mdev_handler {
15	lookup_by_table_id_t dev_lookup;
16};
17
18static struct l3mdev_handler l3mdev_handlers[L3MDEV_TYPE_MAX + 1];
19
20static int l3mdev_check_type(enum l3mdev_type l3type)
21{
22	if (l3type <= L3MDEV_TYPE_UNSPEC || l3type > L3MDEV_TYPE_MAX)
23		return -EINVAL;
24
25	return 0;
26}
27
28int l3mdev_table_lookup_register(enum l3mdev_type l3type,
29				 lookup_by_table_id_t fn)
30{
31	struct l3mdev_handler *hdlr;
32	int res;
33
34	res = l3mdev_check_type(l3type);
35	if (res)
36		return res;
37
38	hdlr = &l3mdev_handlers[l3type];
39
40	spin_lock(&l3mdev_lock);
41
42	if (hdlr->dev_lookup) {
43		res = -EBUSY;
44		goto unlock;
45	}
46
47	hdlr->dev_lookup = fn;
48	res = 0;
49
50unlock:
51	spin_unlock(&l3mdev_lock);
52
53	return res;
54}
55EXPORT_SYMBOL_GPL(l3mdev_table_lookup_register);
56
57void l3mdev_table_lookup_unregister(enum l3mdev_type l3type,
58				    lookup_by_table_id_t fn)
59{
60	struct l3mdev_handler *hdlr;
61
62	if (l3mdev_check_type(l3type))
63		return;
64
65	hdlr = &l3mdev_handlers[l3type];
66
67	spin_lock(&l3mdev_lock);
68
69	if (hdlr->dev_lookup == fn)
70		hdlr->dev_lookup = NULL;
71
72	spin_unlock(&l3mdev_lock);
73}
74EXPORT_SYMBOL_GPL(l3mdev_table_lookup_unregister);
75
76int l3mdev_ifindex_lookup_by_table_id(enum l3mdev_type l3type,
77				      struct net *net, u32 table_id)
78{
79	lookup_by_table_id_t lookup;
80	struct l3mdev_handler *hdlr;
81	int ifindex = -EINVAL;
82	int res;
83
84	res = l3mdev_check_type(l3type);
85	if (res)
86		return res;
87
88	hdlr = &l3mdev_handlers[l3type];
89
90	spin_lock(&l3mdev_lock);
91
92	lookup = hdlr->dev_lookup;
93	if (!lookup)
94		goto unlock;
95
96	ifindex = lookup(net, table_id);
97
98unlock:
99	spin_unlock(&l3mdev_lock);
100
101	return ifindex;
102}
103EXPORT_SYMBOL_GPL(l3mdev_ifindex_lookup_by_table_id);
104
105/**
106 *	l3mdev_master_ifindex_rcu - get index of L3 master device
107 *	@dev: targeted interface
108 */
109
110int l3mdev_master_ifindex_rcu(const struct net_device *dev)
111{
112	int ifindex = 0;
113
114	if (!dev)
115		return 0;
116
117	if (netif_is_l3_master(dev)) {
118		ifindex = dev->ifindex;
119	} else if (netif_is_l3_slave(dev)) {
120		struct net_device *master;
121		struct net_device *_dev = (struct net_device *)dev;
122
123		/* netdev_master_upper_dev_get_rcu calls
124		 * list_first_or_null_rcu to walk the upper dev list.
125		 * list_first_or_null_rcu does not handle a const arg. We aren't
126		 * making changes, just want the master device from that list so
127		 * typecast to remove the const
128		 */
129		master = netdev_master_upper_dev_get_rcu(_dev);
130		if (master)
131			ifindex = master->ifindex;
132	}
133
134	return ifindex;
135}
136EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
137
138/**
139 *	l3mdev_master_upper_ifindex_by_index_rcu - get index of upper l3 master
140 *					       device
141 *	@net: network namespace for device index lookup
142 *	@ifindex: targeted interface
143 */
144int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex)
145{
146	struct net_device *dev;
147
148	dev = dev_get_by_index_rcu(net, ifindex);
149	while (dev && !netif_is_l3_master(dev))
150		dev = netdev_master_upper_dev_get_rcu(dev);
151
152	return dev ? dev->ifindex : 0;
153}
154EXPORT_SYMBOL_GPL(l3mdev_master_upper_ifindex_by_index_rcu);
155
156/**
157 *	l3mdev_fib_table_rcu - get FIB table id associated with an L3
158 *                             master interface
159 *	@dev: targeted interface
160 */
161
162u32 l3mdev_fib_table_rcu(const struct net_device *dev)
163{
164	u32 tb_id = 0;
165
166	if (!dev)
167		return 0;
168
169	if (netif_is_l3_master(dev)) {
170		if (dev->l3mdev_ops->l3mdev_fib_table)
171			tb_id = dev->l3mdev_ops->l3mdev_fib_table(dev);
172	} else if (netif_is_l3_slave(dev)) {
173		/* Users of netdev_master_upper_dev_get_rcu need non-const,
174		 * but current inet_*type functions take a const
175		 */
176		struct net_device *_dev = (struct net_device *) dev;
177		const struct net_device *master;
178
179		master = netdev_master_upper_dev_get_rcu(_dev);
180		if (master &&
181		    master->l3mdev_ops->l3mdev_fib_table)
182			tb_id = master->l3mdev_ops->l3mdev_fib_table(master);
183	}
184
185	return tb_id;
186}
187EXPORT_SYMBOL_GPL(l3mdev_fib_table_rcu);
188
189u32 l3mdev_fib_table_by_index(struct net *net, int ifindex)
190{
191	struct net_device *dev;
192	u32 tb_id = 0;
193
194	if (!ifindex)
195		return 0;
196
197	rcu_read_lock();
198
199	dev = dev_get_by_index_rcu(net, ifindex);
200	if (dev)
201		tb_id = l3mdev_fib_table_rcu(dev);
202
203	rcu_read_unlock();
204
205	return tb_id;
206}
207EXPORT_SYMBOL_GPL(l3mdev_fib_table_by_index);
208
209/**
210 *	l3mdev_link_scope_lookup - IPv6 route lookup based on flow for link
211 *			     local and multicast addresses
212 *	@net: network namespace for device index lookup
213 *	@fl6: IPv6 flow struct for lookup
214 *	This function does not hold refcnt on the returned dst.
215 *	Caller must hold rcu_read_lock().
216 */
217
218struct dst_entry *l3mdev_link_scope_lookup(struct net *net,
219					   struct flowi6 *fl6)
220{
221	struct dst_entry *dst = NULL;
222	struct net_device *dev;
223
224	WARN_ON_ONCE(!rcu_read_lock_held());
225	if (fl6->flowi6_oif) {
226		dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
227		if (dev && netif_is_l3_slave(dev))
228			dev = netdev_master_upper_dev_get_rcu(dev);
229
230		if (dev && netif_is_l3_master(dev) &&
231		    dev->l3mdev_ops->l3mdev_link_scope_lookup)
232			dst = dev->l3mdev_ops->l3mdev_link_scope_lookup(dev, fl6);
233	}
234
235	return dst;
236}
237EXPORT_SYMBOL_GPL(l3mdev_link_scope_lookup);
238
239/**
240 *	l3mdev_fib_rule_match - Determine if flowi references an
241 *				L3 master device
242 *	@net: network namespace for device index lookup
243 *	@fl:  flow struct
244 *	@arg: store the table the rule matched with here
245 */
246
247int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
248			  struct fib_lookup_arg *arg)
249{
250	struct net_device *dev;
251	int rc = 0;
252
253	/* update flow ensures flowi_l3mdev is set when relevant */
254	if (!fl->flowi_l3mdev)
255		return 0;
256
257	rcu_read_lock();
258
259	dev = dev_get_by_index_rcu(net, fl->flowi_l3mdev);
260	if (dev && netif_is_l3_master(dev) &&
261	    dev->l3mdev_ops->l3mdev_fib_table) {
262		arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
263		rc = 1;
264	}
265
266	rcu_read_unlock();
267
268	return rc;
269}
270
271void l3mdev_update_flow(struct net *net, struct flowi *fl)
272{
273	struct net_device *dev;
274
275	rcu_read_lock();
276
277	if (fl->flowi_oif) {
278		dev = dev_get_by_index_rcu(net, fl->flowi_oif);
279		if (dev) {
280			if (!fl->flowi_l3mdev)
281				fl->flowi_l3mdev = l3mdev_master_ifindex_rcu(dev);
282
283			/* oif set to L3mdev directs lookup to its table;
284			 * reset to avoid oif match in fib_lookup
285			 */
286			if (netif_is_l3_master(dev))
287				fl->flowi_oif = 0;
288			goto out;
289		}
290	}
291
292	if (fl->flowi_iif > LOOPBACK_IFINDEX && !fl->flowi_l3mdev) {
293		dev = dev_get_by_index_rcu(net, fl->flowi_iif);
294		if (dev)
295			fl->flowi_l3mdev = l3mdev_master_ifindex_rcu(dev);
296	}
297
298out:
299	rcu_read_unlock();
300}
301EXPORT_SYMBOL_GPL(l3mdev_update_flow);
302