net/l3mdev/l3mdev.c

   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/fib_rules.h>
  14 #include <net/l3mdev.h>
  15
  16 /**
  17  *      l3mdev_master_ifindex - get index of L3 master device
  18  *      @dev: targeted interface
  19  */
  20
  21 int l3mdev_master_ifindex_rcu(const struct net_device *dev)
  22 {
  23         int ifindex = 0;
  24
  25         if (!dev)
  26                 return 0;
  27
  28         if (netif_is_l3_master(dev)) {
  29                 ifindex = dev->ifindex;
  30         } else if (netif_is_l3_slave(dev)) {
  31                 struct net_device *master;
  32                 struct net_device *_dev = (struct net_device *)dev;
  33
  34                 /* netdev_master_upper_dev_get_rcu calls
  35                  * list_first_or_null_rcu to walk the upper dev list.
  36                  * list_first_or_null_rcu does not handle a const arg. We aren't
  37                  * making changes, just want the master device from that list so
  38                  * typecast to remove the const
  39                  */
  40                 master = netdev_master_upper_dev_get_rcu(_dev);
  41                 if (master)
  42                         ifindex = master->ifindex;
  43         }
  44
  45         return ifindex;
  46 }
  47 EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
  48
  49 /**
  50  *      l3mdev_fib_table - get FIB table id associated with an L3
  51  *                             master interface
  52  *      @dev: targeted interface
  53  */
  54
  55 u32 l3mdev_fib_table_rcu(const struct net_device *dev)
  56 {
  57         u32 tb_id = 0;
  58
  59         if (!dev)
  60                 return 0;
  61
  62         if (netif_is_l3_master(dev)) {
  63                 if (dev->l3mdev_ops->l3mdev_fib_table)
  64                         tb_id = dev->l3mdev_ops->l3mdev_fib_table(dev);
  65         } else if (netif_is_l3_slave(dev)) {
  66                 /* Users of netdev_master_upper_dev_get_rcu need non-const,
  67                  * but current inet_*type functions take a const
  68                  */
  69                 struct net_device *_dev = (struct net_device *) dev;
  70                 const struct net_device *master;
  71
  72                 master = netdev_master_upper_dev_get_rcu(_dev);
  73                 if (master &&
  74                     master->l3mdev_ops->l3mdev_fib_table)
  75                         tb_id = master->l3mdev_ops->l3mdev_fib_table(master);
  76         }
  77
  78         return tb_id;
  79 }
  80 EXPORT_SYMBOL_GPL(l3mdev_fib_table_rcu);
  81
  82 u32 l3mdev_fib_table_by_index(struct net *net, int ifindex)
  83 {
  84         struct net_device *dev;
  85         u32 tb_id = 0;
  86
  87         if (!ifindex)
  88                 return 0;
  89
  90         rcu_read_lock();
  91
  92         dev = dev_get_by_index_rcu(net, ifindex);
  93         if (dev)
  94                 tb_id = l3mdev_fib_table_rcu(dev);
  95
  96         rcu_read_unlock();
  97
  98         return tb_id;
  99 }
 100 EXPORT_SYMBOL_GPL(l3mdev_fib_table_by_index);
 101
 102 /**
 103  *      l3mdev_get_rt6_dst - IPv6 route lookup based on flow. Returns
 104  *                           cached route for L3 master device if relevant
 105  *                           to flow
 106  *      @net: network namespace for device index lookup
 107  *      @fl6: IPv6 flow struct for lookup
 108  */
 109
 110 struct dst_entry *l3mdev_get_rt6_dst(struct net *net,
 111                                      struct flowi6 *fl6)
 112 {
 113         struct dst_entry *dst = NULL;
 114         struct net_device *dev;
 115
 116         if (fl6->flowi6_oif) {
 117                 rcu_read_lock();
 118
 119                 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
 120                 if (dev && netif_is_l3_slave(dev))
 121                         dev = netdev_master_upper_dev_get_rcu(dev);
 122
 123                 if (dev && netif_is_l3_master(dev) &&
 124                     dev->l3mdev_ops->l3mdev_get_rt6_dst)
 125                         dst = dev->l3mdev_ops->l3mdev_get_rt6_dst(dev, fl6);
 126
 127                 rcu_read_unlock();
 128         }
 129
 130         return dst;
 131 }
 132 EXPORT_SYMBOL_GPL(l3mdev_get_rt6_dst);
 133
 134 /**
 135  *      l3mdev_get_saddr - get source address for a flow based on an interface
 136  *                         enslaved to an L3 master device
 137  *      @net: network namespace for device index lookup
 138  *      @ifindex: Interface index
 139  *      @fl4: IPv4 flow struct
 140  */
 141
 142 int l3mdev_get_saddr(struct net *net, int ifindex, struct flowi4 *fl4)
 143 {
 144         struct net_device *dev;
 145         int rc = 0;
 146
 147         if (ifindex) {
 148                 rcu_read_lock();
 149
 150                 dev = dev_get_by_index_rcu(net, ifindex);
 151                 if (dev && netif_is_l3_slave(dev))
 152                         dev = netdev_master_upper_dev_get_rcu(dev);
 153
 154                 if (dev && netif_is_l3_master(dev) &&
 155                     dev->l3mdev_ops->l3mdev_get_saddr)
 156                         rc = dev->l3mdev_ops->l3mdev_get_saddr(dev, fl4);
 157
 158                 rcu_read_unlock();
 159         }
 160
 161         return rc;
 162 }
 163 EXPORT_SYMBOL_GPL(l3mdev_get_saddr);
 164
 165 /**
 166  *      l3mdev_fib_rule_match - Determine if flowi references an
 167  *                              L3 master device
 168  *      @net: network namespace for device index lookup
 169  *      @fl:  flow struct
 170  */
 171
 172 int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
 173                           struct fib_lookup_arg *arg)
 174 {
 175         struct net_device *dev;
 176         int rc = 0;
 177
 178         rcu_read_lock();
 179
 180         dev = dev_get_by_index_rcu(net, fl->flowi_oif);
 181         if (dev && netif_is_l3_master(dev) &&
 182             dev->l3mdev_ops->l3mdev_fib_table) {
 183                 arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
 184                 rc = 1;
 185                 goto out;
 186         }
 187
 188         dev = dev_get_by_index_rcu(net, fl->flowi_iif);
 189         if (dev && netif_is_l3_master(dev) &&
 190             dev->l3mdev_ops->l3mdev_fib_table) {
 191                 arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
 192                 rc = 1;
 193                 goto out;
 194         }
 195
 196 out:
 197         rcu_read_unlock();
 198
 199         return rc;
 200 }