LXR linux/net/l3mdev/l3mdev.c

   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 - 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 - 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(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        rcu_read_lock();
 254
 255        dev = dev_get_by_index_rcu(net, fl->flowi_oif);
 256        if (dev && netif_is_l3_master(dev) &&
 257            dev->l3mdev_ops->l3mdev_fib_table) {
 258                arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
 259                rc = 1;
 260                goto out;
 261        }
 262
 263        dev = dev_get_by_index_rcu(net, fl->flowi_iif);
 264        if (dev && netif_is_l3_master(dev) &&
 265            dev->l3mdev_ops->l3mdev_fib_table) {
 266                arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
 267                rc = 1;
 268                goto out;
 269        }
 270
 271out:
 272        rcu_read_unlock();
 273
 274        return rc;
 275}
 276
 277void l3mdev_update_flow(struct net *net, struct flowi *fl)
 278{
 279        struct net_device *dev;
 280        int ifindex;
 281
 282        rcu_read_lock();
 283
 284        if (fl->flowi_oif) {
 285                dev = dev_get_by_index_rcu(net, fl->flowi_oif);
 286                if (dev) {
 287                        ifindex = l3mdev_master_ifindex_rcu(dev);
 288                        if (ifindex) {
 289                                fl->flowi_oif = ifindex;
 290                                fl->flowi_flags |= FLOWI_FLAG_SKIP_NH_OIF;
 291                                goto out;
 292                        }
 293                }
 294        }
 295
 296        if (fl->flowi_iif) {
 297                dev = dev_get_by_index_rcu(net, fl->flowi_iif);
 298                if (dev) {
 299                        ifindex = l3mdev_master_ifindex_rcu(dev);
 300                        if (ifindex) {
 301                                fl->flowi_iif = ifindex;
 302                                fl->flowi_flags |= FLOWI_FLAG_SKIP_NH_OIF;
 303                        }
 304                }
 305        }
 306
 307out:
 308        rcu_read_unlock();
 309}
 310EXPORT_SYMBOL_GPL(l3mdev_update_flow);
 311