net/bridge/br_mst.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Bridge Multiple Spanning Tree Support
   4  *
   5  *      Authors:
   6  *      Tobias Waldekranz               <tobias@waldekranz.com>
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <net/switchdev.h>
  11
  12 #include "br_private.h"
  13
  14 DEFINE_STATIC_KEY_FALSE(br_mst_used);
  15
  16 bool br_mst_enabled(const struct net_device *dev)
  17 {
  18         if (!netif_is_bridge_master(dev))
  19                 return false;
  20
  21         return br_opt_get(netdev_priv(dev), BROPT_MST_ENABLED);
  22 }
  23 EXPORT_SYMBOL_GPL(br_mst_enabled);
  24
  25 int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long *vids)
  26 {
  27         const struct net_bridge_vlan_group *vg;
  28         const struct net_bridge_vlan *v;
  29         const struct net_bridge *br;
  30
  31         ASSERT_RTNL();
  32
  33         if (!netif_is_bridge_master(dev))
  34                 return -EINVAL;
  35
  36         br = netdev_priv(dev);
  37         if (!br_opt_get(br, BROPT_MST_ENABLED))
  38                 return -EINVAL;
  39
  40         vg = br_vlan_group(br);
  41
  42         list_for_each_entry(v, &vg->vlan_list, vlist) {
  43                 if (v->msti == msti)
  44                         __set_bit(v->vid, vids);
  45         }
  46
  47         return 0;
  48 }
  49 EXPORT_SYMBOL_GPL(br_mst_get_info);
  50
  51 int br_mst_get_state(const struct net_device *dev, u16 msti, u8 *state)
  52 {
  53         const struct net_bridge_port *p = NULL;
  54         const struct net_bridge_vlan_group *vg;
  55         const struct net_bridge_vlan *v;
  56
  57         ASSERT_RTNL();
  58
  59         p = br_port_get_check_rtnl(dev);
  60         if (!p || !br_opt_get(p->br, BROPT_MST_ENABLED))
  61                 return -EINVAL;
  62
  63         vg = nbp_vlan_group(p);
  64
  65         list_for_each_entry(v, &vg->vlan_list, vlist) {
  66                 if (v->brvlan->msti == msti) {
  67                         *state = v->state;
  68                         return 0;
  69                 }
  70         }
  71
  72         return -ENOENT;
  73 }
  74 EXPORT_SYMBOL_GPL(br_mst_get_state);
  75
  76 static void br_mst_vlan_set_state(struct net_bridge_vlan_group *vg,
  77                                   struct net_bridge_vlan *v,
  78                                   u8 state)
  79 {
  80         if (br_vlan_get_state(v) == state)
  81                 return;
  82
  83         br_vlan_set_state(v, state);
  84
  85         if (v->vid == vg->pvid)
  86                 br_vlan_set_pvid_state(vg, state);
  87 }
  88
  89 int br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state,
  90                      struct netlink_ext_ack *extack)
  91 {
  92         struct switchdev_attr attr = {
  93                 .id = SWITCHDEV_ATTR_ID_PORT_MST_STATE,
  94                 .orig_dev = p->dev,
  95                 .u.mst_state = {
  96                         .msti = msti,
  97                         .state = state,
  98                 },
  99         };
 100         struct net_bridge_vlan_group *vg;
 101         struct net_bridge_vlan *v;
 102         int err = 0;
 103
 104         rcu_read_lock();
 105         vg = nbp_vlan_group_rcu(p);
 106         if (!vg)
 107                 goto out;
 108
 109         /* MSTI 0 (CST) state changes are notified via the regular
 110          * SWITCHDEV_ATTR_ID_PORT_STP_STATE.
 111          */
 112         if (msti) {
 113                 err = switchdev_port_attr_set(p->dev, &attr, extack);
 114                 if (err && err != -EOPNOTSUPP)
 115                         goto out;
 116         }
 117
 118         err = 0;
 119         list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
 120                 if (v->brvlan->msti != msti)
 121                         continue;
 122
 123                 br_mst_vlan_set_state(vg, v, state);
 124         }
 125
 126 out:
 127         rcu_read_unlock();
 128         return err;
 129 }
 130
 131 static void br_mst_vlan_sync_state(struct net_bridge_vlan *pv, u16 msti)
 132 {
 133         struct net_bridge_vlan_group *vg = nbp_vlan_group(pv->port);
 134         struct net_bridge_vlan *v;
 135
 136         list_for_each_entry(v, &vg->vlan_list, vlist) {
 137                 /* If this port already has a defined state in this
 138                  * MSTI (through some other VLAN membership), inherit
 139                  * it.
 140                  */
 141                 if (v != pv && v->brvlan->msti == msti) {
 142                         br_mst_vlan_set_state(vg, pv, v->state);
 143                         return;
 144                 }
 145         }
 146
 147         /* Otherwise, start out in a new MSTI with all ports disabled. */
 148         return br_mst_vlan_set_state(vg, pv, BR_STATE_DISABLED);
 149 }
 150
 151 int br_mst_vlan_set_msti(struct net_bridge_vlan *mv, u16 msti)
 152 {
 153         struct switchdev_attr attr = {
 154                 .id = SWITCHDEV_ATTR_ID_VLAN_MSTI,
 155                 .orig_dev = mv->br->dev,
 156                 .u.vlan_msti = {
 157                         .vid = mv->vid,
 158                         .msti = msti,
 159                 },
 160         };
 161         struct net_bridge_vlan_group *vg;
 162         struct net_bridge_vlan *pv;
 163         struct net_bridge_port *p;
 164         int err;
 165
 166         if (mv->msti == msti)
 167                 return 0;
 168
 169         err = switchdev_port_attr_set(mv->br->dev, &attr, NULL);
 170         if (err && err != -EOPNOTSUPP)
 171                 return err;
 172
 173         mv->msti = msti;
 174
 175         list_for_each_entry(p, &mv->br->port_list, list) {
 176                 vg = nbp_vlan_group(p);
 177
 178                 pv = br_vlan_find(vg, mv->vid);
 179                 if (pv)
 180                         br_mst_vlan_sync_state(pv, msti);
 181         }
 182
 183         return 0;
 184 }
 185
 186 void br_mst_vlan_init_state(struct net_bridge_vlan *v)
 187 {
 188         /* VLANs always start out in MSTI 0 (CST) */
 189         v->msti = 0;
 190
 191         if (br_vlan_is_master(v))
 192                 v->state = BR_STATE_FORWARDING;
 193         else
 194                 v->state = v->port->state;
 195 }
 196
 197 int br_mst_set_enabled(struct net_bridge *br, bool on,
 198                        struct netlink_ext_ack *extack)
 199 {
 200         struct switchdev_attr attr = {
 201                 .id = SWITCHDEV_ATTR_ID_BRIDGE_MST,
 202                 .orig_dev = br->dev,
 203                 .u.mst = on,
 204         };
 205         struct net_bridge_vlan_group *vg;
 206         struct net_bridge_port *p;
 207         int err;
 208
 209         list_for_each_entry(p, &br->port_list, list) {
 210                 vg = nbp_vlan_group(p);
 211
 212                 if (!vg->num_vlans)
 213                         continue;
 214
 215                 NL_SET_ERR_MSG(extack,
 216                                "MST mode can't be changed while VLANs exist");
 217                 return -EBUSY;
 218         }
 219
 220         if (br_opt_get(br, BROPT_MST_ENABLED) == on)
 221                 return 0;
 222
 223         err = switchdev_port_attr_set(br->dev, &attr, extack);
 224         if (err && err != -EOPNOTSUPP)
 225                 return err;
 226
 227         if (on)
 228                 static_branch_enable(&br_mst_used);
 229         else
 230                 static_branch_disable(&br_mst_used);
 231
 232         br_opt_toggle(br, BROPT_MST_ENABLED, on);
 233         return 0;
 234 }
 235
 236 size_t br_mst_info_size(const struct net_bridge_vlan_group *vg)
 237 {
 238         DECLARE_BITMAP(seen, VLAN_N_VID) = { 0 };
 239         const struct net_bridge_vlan *v;
 240         size_t sz;
 241
 242         /* IFLA_BRIDGE_MST */
 243         sz = nla_total_size(0);
 244
 245         list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
 246                 if (test_bit(v->brvlan->msti, seen))
 247                         continue;
 248
 249                 /* IFLA_BRIDGE_MST_ENTRY */
 250                 sz += nla_total_size(0) +
 251                         /* IFLA_BRIDGE_MST_ENTRY_MSTI */
 252                         nla_total_size(sizeof(u16)) +
 253                         /* IFLA_BRIDGE_MST_ENTRY_STATE */
 254                         nla_total_size(sizeof(u8));
 255
 256                 __set_bit(v->brvlan->msti, seen);
 257         }
 258
 259         return sz;
 260 }
 261
 262 int br_mst_fill_info(struct sk_buff *skb,
 263                      const struct net_bridge_vlan_group *vg)
 264 {
 265         DECLARE_BITMAP(seen, VLAN_N_VID) = { 0 };
 266         const struct net_bridge_vlan *v;
 267         struct nlattr *nest;
 268         int err = 0;
 269
 270         list_for_each_entry(v, &vg->vlan_list, vlist) {
 271                 if (test_bit(v->brvlan->msti, seen))
 272                         continue;
 273
 274                 nest = nla_nest_start_noflag(skb, IFLA_BRIDGE_MST_ENTRY);
 275                 if (!nest ||
 276                     nla_put_u16(skb, IFLA_BRIDGE_MST_ENTRY_MSTI, v->brvlan->msti) ||
 277                     nla_put_u8(skb, IFLA_BRIDGE_MST_ENTRY_STATE, v->state)) {
 278                         err = -EMSGSIZE;
 279                         break;
 280                 }
 281                 nla_nest_end(skb, nest);
 282
 283                 __set_bit(v->brvlan->msti, seen);
 284         }
 285
 286         return err;
 287 }
 288
 289 static const struct nla_policy br_mst_nl_policy[IFLA_BRIDGE_MST_ENTRY_MAX + 1] = {
 290         [IFLA_BRIDGE_MST_ENTRY_MSTI] = NLA_POLICY_RANGE(NLA_U16,
 291                                                    1, /* 0 reserved for CST */
 292                                                    VLAN_N_VID - 1),
 293         [IFLA_BRIDGE_MST_ENTRY_STATE] = NLA_POLICY_RANGE(NLA_U8,
 294                                                     BR_STATE_DISABLED,
 295                                                     BR_STATE_BLOCKING),
 296 };
 297
 298 static int br_mst_process_one(struct net_bridge_port *p,
 299                               const struct nlattr *attr,
 300                               struct netlink_ext_ack *extack)
 301 {
 302         struct nlattr *tb[IFLA_BRIDGE_MST_ENTRY_MAX + 1];
 303         u16 msti;
 304         u8 state;
 305         int err;
 306
 307         err = nla_parse_nested(tb, IFLA_BRIDGE_MST_ENTRY_MAX, attr,
 308                                br_mst_nl_policy, extack);
 309         if (err)
 310                 return err;
 311
 312         if (!tb[IFLA_BRIDGE_MST_ENTRY_MSTI]) {
 313                 NL_SET_ERR_MSG_MOD(extack, "MSTI not specified");
 314                 return -EINVAL;
 315         }
 316
 317         if (!tb[IFLA_BRIDGE_MST_ENTRY_STATE]) {
 318                 NL_SET_ERR_MSG_MOD(extack, "State not specified");
 319                 return -EINVAL;
 320         }
 321
 322         msti = nla_get_u16(tb[IFLA_BRIDGE_MST_ENTRY_MSTI]);
 323         state = nla_get_u8(tb[IFLA_BRIDGE_MST_ENTRY_STATE]);
 324
 325         return br_mst_set_state(p, msti, state, extack);
 326 }
 327
 328 int br_mst_process(struct net_bridge_port *p, const struct nlattr *mst_attr,
 329                    struct netlink_ext_ack *extack)
 330 {
 331         struct nlattr *attr;
 332         int err, msts = 0;
 333         int rem;
 334
 335         if (!br_opt_get(p->br, BROPT_MST_ENABLED)) {
 336                 NL_SET_ERR_MSG_MOD(extack, "Can't modify MST state when MST is disabled");
 337                 return -EBUSY;
 338         }
 339
 340         nla_for_each_nested(attr, mst_attr, rem) {
 341                 switch (nla_type(attr)) {
 342                 case IFLA_BRIDGE_MST_ENTRY:
 343                         err = br_mst_process_one(p, attr, extack);
 344                         break;
 345                 default:
 346                         continue;
 347                 }
 348
 349                 msts++;
 350                 if (err)
 351                         break;
 352         }
 353
 354         if (!msts) {
 355                 NL_SET_ERR_MSG_MOD(extack, "Found no MST entries to process");
 356                 err = -EINVAL;
 357         }
 358
 359         return err;
 360 }