xref: /openbmc/linux/net/l3mdev/l3mdev.c (revision 4f205687)
1 /*
2  * net/l3mdev/l3mdev.c - L3 master device implementation
3  * Copyright (c) 2015 Cumulus Networks
4  * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  */
11 
12 #include <linux/netdevice.h>
13 #include <net/l3mdev.h>
14 
15 /**
16  *	l3mdev_master_ifindex - get index of L3 master device
17  *	@dev: targeted interface
18  */
19 
20 int l3mdev_master_ifindex_rcu(const struct net_device *dev)
21 {
22 	int ifindex = 0;
23 
24 	if (!dev)
25 		return 0;
26 
27 	if (netif_is_l3_master(dev)) {
28 		ifindex = dev->ifindex;
29 	} else if (netif_is_l3_slave(dev)) {
30 		struct net_device *master;
31 		struct net_device *_dev = (struct net_device *)dev;
32 
33 		/* netdev_master_upper_dev_get_rcu calls
34 		 * list_first_or_null_rcu to walk the upper dev list.
35 		 * list_first_or_null_rcu does not handle a const arg. We aren't
36 		 * making changes, just want the master device from that list so
37 		 * typecast to remove the const
38 		 */
39 		master = netdev_master_upper_dev_get_rcu(_dev);
40 		if (master)
41 			ifindex = master->ifindex;
42 	}
43 
44 	return ifindex;
45 }
46 EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
47 
48 /**
49  *	l3mdev_fib_table - get FIB table id associated with an L3
50  *                             master interface
51  *	@dev: targeted interface
52  */
53 
54 u32 l3mdev_fib_table_rcu(const struct net_device *dev)
55 {
56 	u32 tb_id = 0;
57 
58 	if (!dev)
59 		return 0;
60 
61 	if (netif_is_l3_master(dev)) {
62 		if (dev->l3mdev_ops->l3mdev_fib_table)
63 			tb_id = dev->l3mdev_ops->l3mdev_fib_table(dev);
64 	} else if (netif_is_l3_slave(dev)) {
65 		/* Users of netdev_master_upper_dev_get_rcu need non-const,
66 		 * but current inet_*type functions take a const
67 		 */
68 		struct net_device *_dev = (struct net_device *) dev;
69 		const struct net_device *master;
70 
71 		master = netdev_master_upper_dev_get_rcu(_dev);
72 		if (master &&
73 		    master->l3mdev_ops->l3mdev_fib_table)
74 			tb_id = master->l3mdev_ops->l3mdev_fib_table(master);
75 	}
76 
77 	return tb_id;
78 }
79 EXPORT_SYMBOL_GPL(l3mdev_fib_table_rcu);
80 
81 u32 l3mdev_fib_table_by_index(struct net *net, int ifindex)
82 {
83 	struct net_device *dev;
84 	u32 tb_id = 0;
85 
86 	if (!ifindex)
87 		return 0;
88 
89 	rcu_read_lock();
90 
91 	dev = dev_get_by_index_rcu(net, ifindex);
92 	if (dev)
93 		tb_id = l3mdev_fib_table_rcu(dev);
94 
95 	rcu_read_unlock();
96 
97 	return tb_id;
98 }
99 EXPORT_SYMBOL_GPL(l3mdev_fib_table_by_index);
100 
101 /**
102  *	l3mdev_get_rt6_dst - IPv6 route lookup based on flow. Returns
103  *			     cached route for L3 master device if relevant
104  *			     to flow
105  *	@net: network namespace for device index lookup
106  *	@fl6: IPv6 flow struct for lookup
107  */
108 
109 struct dst_entry *l3mdev_get_rt6_dst(struct net *net,
110 				     const struct flowi6 *fl6)
111 {
112 	struct dst_entry *dst = NULL;
113 	struct net_device *dev;
114 
115 	if (fl6->flowi6_oif) {
116 		rcu_read_lock();
117 
118 		dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
119 		if (dev && netif_is_l3_slave(dev))
120 			dev = netdev_master_upper_dev_get_rcu(dev);
121 
122 		if (dev && netif_is_l3_master(dev) &&
123 		    dev->l3mdev_ops->l3mdev_get_rt6_dst)
124 			dst = dev->l3mdev_ops->l3mdev_get_rt6_dst(dev, fl6);
125 
126 		rcu_read_unlock();
127 	}
128 
129 	return dst;
130 }
131 EXPORT_SYMBOL_GPL(l3mdev_get_rt6_dst);
132 
133 /**
134  *	l3mdev_get_saddr - get source address for a flow based on an interface
135  *			   enslaved to an L3 master device
136  *	@net: network namespace for device index lookup
137  *	@ifindex: Interface index
138  *	@fl4: IPv4 flow struct
139  */
140 
141 int l3mdev_get_saddr(struct net *net, int ifindex, struct flowi4 *fl4)
142 {
143 	struct net_device *dev;
144 	int rc = 0;
145 
146 	if (ifindex) {
147 		rcu_read_lock();
148 
149 		dev = dev_get_by_index_rcu(net, ifindex);
150 		if (dev && netif_is_l3_slave(dev))
151 			dev = netdev_master_upper_dev_get_rcu(dev);
152 
153 		if (dev && netif_is_l3_master(dev) &&
154 		    dev->l3mdev_ops->l3mdev_get_saddr)
155 			rc = dev->l3mdev_ops->l3mdev_get_saddr(dev, fl4);
156 
157 		rcu_read_unlock();
158 	}
159 
160 	return rc;
161 }
162 EXPORT_SYMBOL_GPL(l3mdev_get_saddr);
163