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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
12/**
13 * l3mdev_master_ifindex - get index of L3 master device
14 * @dev: targeted interface
15 */
16
17int l3mdev_master_ifindex_rcu(const struct net_device *dev)
18{
19 int ifindex = 0;
20
21 if (!dev)
22 return 0;
23
24 if (netif_is_l3_master(dev)) {
25 ifindex = dev->ifindex;
26 } else if (netif_is_l3_slave(dev)) {
27 struct net_device *master;
28 struct net_device *_dev = (struct net_device *)dev;
29
30 /* netdev_master_upper_dev_get_rcu calls
31 * list_first_or_null_rcu to walk the upper dev list.
32 * list_first_or_null_rcu does not handle a const arg. We aren't
33 * making changes, just want the master device from that list so
34 * typecast to remove the const
35 */
36 master = netdev_master_upper_dev_get_rcu(_dev);
37 if (master)
38 ifindex = master->ifindex;
39 }
40
41 return ifindex;
42}
43EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
44
45/**
46 * l3mdev_master_upper_ifindex_by_index - get index of upper l3 master
47 * device
48 * @net: network namespace for device index lookup
49 * @ifindex: targeted interface
50 */
51int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex)
52{
53 struct net_device *dev;
54
55 dev = dev_get_by_index_rcu(net, ifindex);
56 while (dev && !netif_is_l3_master(dev))
57 dev = netdev_master_upper_dev_get(dev);
58
59 return dev ? dev->ifindex : 0;
60}
61EXPORT_SYMBOL_GPL(l3mdev_master_upper_ifindex_by_index_rcu);
62
63/**
64 * l3mdev_fib_table - get FIB table id associated with an L3
65 * master interface
66 * @dev: targeted interface
67 */
68
69u32 l3mdev_fib_table_rcu(const struct net_device *dev)
70{
71 u32 tb_id = 0;
72
73 if (!dev)
74 return 0;
75
76 if (netif_is_l3_master(dev)) {
77 if (dev->l3mdev_ops->l3mdev_fib_table)
78 tb_id = dev->l3mdev_ops->l3mdev_fib_table(dev);
79 } else if (netif_is_l3_slave(dev)) {
80 /* Users of netdev_master_upper_dev_get_rcu need non-const,
81 * but current inet_*type functions take a const
82 */
83 struct net_device *_dev = (struct net_device *) dev;
84 const struct net_device *master;
85
86 master = netdev_master_upper_dev_get_rcu(_dev);
87 if (master &&
88 master->l3mdev_ops->l3mdev_fib_table)
89 tb_id = master->l3mdev_ops->l3mdev_fib_table(master);
90 }
91
92 return tb_id;
93}
94EXPORT_SYMBOL_GPL(l3mdev_fib_table_rcu);
95
96u32 l3mdev_fib_table_by_index(struct net *net, int ifindex)
97{
98 struct net_device *dev;
99 u32 tb_id = 0;
100
101 if (!ifindex)
102 return 0;
103
104 rcu_read_lock();
105
106 dev = dev_get_by_index_rcu(net, ifindex);
107 if (dev)
108 tb_id = l3mdev_fib_table_rcu(dev);
109
110 rcu_read_unlock();
111
112 return tb_id;
113}
114EXPORT_SYMBOL_GPL(l3mdev_fib_table_by_index);
115
116/**
117 * l3mdev_link_scope_lookup - IPv6 route lookup based on flow for link
118 * local and multicast addresses
119 * @net: network namespace for device index lookup
120 * @fl6: IPv6 flow struct for lookup
121 * This function does not hold refcnt on the returned dst.
122 * Caller must hold rcu_read_lock().
123 */
124
125struct dst_entry *l3mdev_link_scope_lookup(struct net *net,
126 struct flowi6 *fl6)
127{
128 struct dst_entry *dst = NULL;
129 struct net_device *dev;
130
131 WARN_ON_ONCE(!rcu_read_lock_held());
132 if (fl6->flowi6_oif) {
133 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
134 if (dev && netif_is_l3_slave(dev))
135 dev = netdev_master_upper_dev_get_rcu(dev);
136
137 if (dev && netif_is_l3_master(dev) &&
138 dev->l3mdev_ops->l3mdev_link_scope_lookup)
139 dst = dev->l3mdev_ops->l3mdev_link_scope_lookup(dev, fl6);
140 }
141
142 return dst;
143}
144EXPORT_SYMBOL_GPL(l3mdev_link_scope_lookup);
145
146/**
147 * l3mdev_fib_rule_match - Determine if flowi references an
148 * L3 master device
149 * @net: network namespace for device index lookup
150 * @fl: flow struct
151 */
152
153int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
154 struct fib_lookup_arg *arg)
155{
156 struct net_device *dev;
157 int rc = 0;
158
159 rcu_read_lock();
160
161 dev = dev_get_by_index_rcu(net, fl->flowi_oif);
162 if (dev && netif_is_l3_master(dev) &&
163 dev->l3mdev_ops->l3mdev_fib_table) {
164 arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
165 rc = 1;
166 goto out;
167 }
168
169 dev = dev_get_by_index_rcu(net, fl->flowi_iif);
170 if (dev && netif_is_l3_master(dev) &&
171 dev->l3mdev_ops->l3mdev_fib_table) {
172 arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
173 rc = 1;
174 goto out;
175 }
176
177out:
178 rcu_read_unlock();
179
180 return rc;
181}
182
183void l3mdev_update_flow(struct net *net, struct flowi *fl)
184{
185 struct net_device *dev;
186 int ifindex;
187
188 rcu_read_lock();
189
190 if (fl->flowi_oif) {
191 dev = dev_get_by_index_rcu(net, fl->flowi_oif);
192 if (dev) {
193 ifindex = l3mdev_master_ifindex_rcu(dev);
194 if (ifindex) {
195 fl->flowi_oif = ifindex;
196 fl->flowi_flags |= FLOWI_FLAG_SKIP_NH_OIF;
197 goto out;
198 }
199 }
200 }
201
202 if (fl->flowi_iif) {
203 dev = dev_get_by_index_rcu(net, fl->flowi_iif);
204 if (dev) {
205 ifindex = l3mdev_master_ifindex_rcu(dev);
206 if (ifindex) {
207 fl->flowi_iif = ifindex;
208 fl->flowi_flags |= FLOWI_FLAG_SKIP_NH_OIF;
209 }
210 }
211 }
212
213out:
214 rcu_read_unlock();
215}
216EXPORT_SYMBOL_GPL(l3mdev_update_flow);