net/dsa/conduit.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Handling of a conduit device, switching frames via its switch fabric CPU port
   4  *
   5  * Copyright (c) 2017 Savoir-faire Linux Inc.
   6  *      Vivien Didelot <vivien.didelot@savoirfairelinux.com>
   7  */
   8
   9 #include <linux/ethtool.h>
  10 #include <linux/netdevice.h>
  11 #include <linux/netlink.h>
  12 #include <net/dsa.h>
  13
  14 #include "conduit.h"
  15 #include "dsa.h"
  16 #include "port.h"
  17 #include "tag.h"
  18
  19 static int dsa_conduit_get_regs_len(struct net_device *dev)
  20 {
  21         struct dsa_port *cpu_dp = dev->dsa_ptr;
  22         const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
  23         struct dsa_switch *ds = cpu_dp->ds;
  24         int port = cpu_dp->index;
  25         int ret = 0;
  26         int len;
  27
  28         if (ops->get_regs_len) {
  29                 len = ops->get_regs_len(dev);
  30                 if (len < 0)
  31                         return len;
  32                 ret += len;
  33         }
  34
  35         ret += sizeof(struct ethtool_drvinfo);
  36         ret += sizeof(struct ethtool_regs);
  37
  38         if (ds->ops->get_regs_len) {
  39                 len = ds->ops->get_regs_len(ds, port);
  40                 if (len < 0)
  41                         return len;
  42                 ret += len;
  43         }
  44
  45         return ret;
  46 }
  47
  48 static void dsa_conduit_get_regs(struct net_device *dev,
  49                                  struct ethtool_regs *regs, void *data)
  50 {
  51         struct dsa_port *cpu_dp = dev->dsa_ptr;
  52         const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
  53         struct dsa_switch *ds = cpu_dp->ds;
  54         struct ethtool_drvinfo *cpu_info;
  55         struct ethtool_regs *cpu_regs;
  56         int port = cpu_dp->index;
  57         int len;
  58
  59         if (ops->get_regs_len && ops->get_regs) {
  60                 len = ops->get_regs_len(dev);
  61                 if (len < 0)
  62                         return;
  63                 regs->len = len;
  64                 ops->get_regs(dev, regs, data);
  65                 data += regs->len;
  66         }
  67
  68         cpu_info = (struct ethtool_drvinfo *)data;
  69         strscpy(cpu_info->driver, "dsa", sizeof(cpu_info->driver));
  70         data += sizeof(*cpu_info);
  71         cpu_regs = (struct ethtool_regs *)data;
  72         data += sizeof(*cpu_regs);
  73
  74         if (ds->ops->get_regs_len && ds->ops->get_regs) {
  75                 len = ds->ops->get_regs_len(ds, port);
  76                 if (len < 0)
  77                         return;
  78                 cpu_regs->len = len;
  79                 ds->ops->get_regs(ds, port, cpu_regs, data);
  80         }
  81 }
  82
  83 static void dsa_conduit_get_ethtool_stats(struct net_device *dev,
  84                                           struct ethtool_stats *stats,
  85                                           uint64_t *data)
  86 {
  87         struct dsa_port *cpu_dp = dev->dsa_ptr;
  88         const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
  89         struct dsa_switch *ds = cpu_dp->ds;
  90         int port = cpu_dp->index;
  91         int count = 0;
  92
  93         if (ops->get_sset_count && ops->get_ethtool_stats) {
  94                 count = ops->get_sset_count(dev, ETH_SS_STATS);
  95                 ops->get_ethtool_stats(dev, stats, data);
  96         }
  97
  98         if (ds->ops->get_ethtool_stats)
  99                 ds->ops->get_ethtool_stats(ds, port, data + count);
 100 }
 101
 102 static void dsa_conduit_get_ethtool_phy_stats(struct net_device *dev,
 103                                               struct ethtool_stats *stats,
 104                                               uint64_t *data)
 105 {
 106         struct dsa_port *cpu_dp = dev->dsa_ptr;
 107         const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
 108         struct dsa_switch *ds = cpu_dp->ds;
 109         int port = cpu_dp->index;
 110         int count = 0;
 111
 112         if (dev->phydev && !ops->get_ethtool_phy_stats) {
 113                 count = phy_ethtool_get_sset_count(dev->phydev);
 114                 if (count >= 0)
 115                         phy_ethtool_get_stats(dev->phydev, stats, data);
 116         } else if (ops->get_sset_count && ops->get_ethtool_phy_stats) {
 117                 count = ops->get_sset_count(dev, ETH_SS_PHY_STATS);
 118                 ops->get_ethtool_phy_stats(dev, stats, data);
 119         }
 120
 121         if (count < 0)
 122                 count = 0;
 123
 124         if (ds->ops->get_ethtool_phy_stats)
 125                 ds->ops->get_ethtool_phy_stats(ds, port, data + count);
 126 }
 127
 128 static int dsa_conduit_get_sset_count(struct net_device *dev, int sset)
 129 {
 130         struct dsa_port *cpu_dp = dev->dsa_ptr;
 131         const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
 132         struct dsa_switch *ds = cpu_dp->ds;
 133         int count = 0;
 134
 135         if (sset == ETH_SS_PHY_STATS && dev->phydev &&
 136             !ops->get_ethtool_phy_stats)
 137                 count = phy_ethtool_get_sset_count(dev->phydev);
 138         else if (ops->get_sset_count)
 139                 count = ops->get_sset_count(dev, sset);
 140
 141         if (count < 0)
 142                 count = 0;
 143
 144         if (ds->ops->get_sset_count)
 145                 count += ds->ops->get_sset_count(ds, cpu_dp->index, sset);
 146
 147         return count;
 148 }
 149
 150 static void dsa_conduit_get_strings(struct net_device *dev, uint32_t stringset,
 151                                     uint8_t *data)
 152 {
 153         struct dsa_port *cpu_dp = dev->dsa_ptr;
 154         const struct ethtool_ops *ops = cpu_dp->orig_ethtool_ops;
 155         struct dsa_switch *ds = cpu_dp->ds;
 156         int port = cpu_dp->index;
 157         int len = ETH_GSTRING_LEN;
 158         int mcount = 0, count, i;
 159         uint8_t pfx[4];
 160         uint8_t *ndata;
 161
 162         snprintf(pfx, sizeof(pfx), "p%.2d", port);
 163         /* We do not want to be NULL-terminated, since this is a prefix */
 164         pfx[sizeof(pfx) - 1] = '_';
 165
 166         if (stringset == ETH_SS_PHY_STATS && dev->phydev &&
 167             !ops->get_ethtool_phy_stats) {
 168                 mcount = phy_ethtool_get_sset_count(dev->phydev);
 169                 if (mcount < 0)
 170                         mcount = 0;
 171                 else
 172                         phy_ethtool_get_strings(dev->phydev, data);
 173         } else if (ops->get_sset_count && ops->get_strings) {
 174                 mcount = ops->get_sset_count(dev, stringset);
 175                 if (mcount < 0)
 176                         mcount = 0;
 177                 ops->get_strings(dev, stringset, data);
 178         }
 179
 180         if (ds->ops->get_strings) {
 181                 ndata = data + mcount * len;
 182                 /* This function copies ETH_GSTRINGS_LEN bytes, we will mangle
 183                  * the output after to prepend our CPU port prefix we
 184                  * constructed earlier
 185                  */
 186                 ds->ops->get_strings(ds, port, stringset, ndata);
 187                 count = ds->ops->get_sset_count(ds, port, stringset);
 188                 if (count < 0)
 189                         return;
 190                 for (i = 0; i < count; i++) {
 191                         memmove(ndata + (i * len + sizeof(pfx)),
 192                                 ndata + i * len, len - sizeof(pfx));
 193                         memcpy(ndata + i * len, pfx, sizeof(pfx));
 194                 }
 195         }
 196 }
 197
 198 /* Deny PTP operations on conduit if there is at least one switch in the tree
 199  * that is PTP capable.
 200  */
 201 int __dsa_conduit_hwtstamp_validate(struct net_device *dev,
 202                                     const struct kernel_hwtstamp_config *config,
 203                                     struct netlink_ext_ack *extack)
 204 {
 205         struct dsa_port *cpu_dp = dev->dsa_ptr;
 206         struct dsa_switch *ds = cpu_dp->ds;
 207         struct dsa_switch_tree *dst;
 208         struct dsa_port *dp;
 209
 210         dst = ds->dst;
 211
 212         list_for_each_entry(dp, &dst->ports, list) {
 213                 if (dsa_port_supports_hwtstamp(dp)) {
 214                         NL_SET_ERR_MSG(extack,
 215                                        "HW timestamping not allowed on DSA conduit when switch supports the operation");
 216                         return -EBUSY;
 217                 }
 218         }
 219
 220         return 0;
 221 }
 222
 223 static int dsa_conduit_ethtool_setup(struct net_device *dev)
 224 {
 225         struct dsa_port *cpu_dp = dev->dsa_ptr;
 226         struct dsa_switch *ds = cpu_dp->ds;
 227         struct ethtool_ops *ops;
 228
 229         if (netif_is_lag_master(dev))
 230                 return 0;
 231
 232         ops = devm_kzalloc(ds->dev, sizeof(*ops), GFP_KERNEL);
 233         if (!ops)
 234                 return -ENOMEM;
 235
 236         cpu_dp->orig_ethtool_ops = dev->ethtool_ops;
 237         if (cpu_dp->orig_ethtool_ops)
 238                 memcpy(ops, cpu_dp->orig_ethtool_ops, sizeof(*ops));
 239
 240         ops->get_regs_len = dsa_conduit_get_regs_len;
 241         ops->get_regs = dsa_conduit_get_regs;
 242         ops->get_sset_count = dsa_conduit_get_sset_count;
 243         ops->get_ethtool_stats = dsa_conduit_get_ethtool_stats;
 244         ops->get_strings = dsa_conduit_get_strings;
 245         ops->get_ethtool_phy_stats = dsa_conduit_get_ethtool_phy_stats;
 246
 247         dev->ethtool_ops = ops;
 248
 249         return 0;
 250 }
 251
 252 static void dsa_conduit_ethtool_teardown(struct net_device *dev)
 253 {
 254         struct dsa_port *cpu_dp = dev->dsa_ptr;
 255
 256         if (netif_is_lag_master(dev))
 257                 return;
 258
 259         dev->ethtool_ops = cpu_dp->orig_ethtool_ops;
 260         cpu_dp->orig_ethtool_ops = NULL;
 261 }
 262
 263 /* Keep the conduit always promiscuous if the tagging protocol requires that
 264  * (garbles MAC DA) or if it doesn't support unicast filtering, case in which
 265  * it would revert to promiscuous mode as soon as we call dev_uc_add() on it
 266  * anyway.
 267  */
 268 static void dsa_conduit_set_promiscuity(struct net_device *dev, int inc)
 269 {
 270         const struct dsa_device_ops *ops = dev->dsa_ptr->tag_ops;
 271
 272         if ((dev->priv_flags & IFF_UNICAST_FLT) && !ops->promisc_on_conduit)
 273                 return;
 274
 275         ASSERT_RTNL();
 276
 277         dev_set_promiscuity(dev, inc);
 278 }
 279
 280 static ssize_t tagging_show(struct device *d, struct device_attribute *attr,
 281                             char *buf)
 282 {
 283         struct net_device *dev = to_net_dev(d);
 284         struct dsa_port *cpu_dp = dev->dsa_ptr;
 285
 286         return sysfs_emit(buf, "%s\n",
 287                        dsa_tag_protocol_to_str(cpu_dp->tag_ops));
 288 }
 289
 290 static ssize_t tagging_store(struct device *d, struct device_attribute *attr,
 291                              const char *buf, size_t count)
 292 {
 293         const struct dsa_device_ops *new_tag_ops, *old_tag_ops;
 294         const char *end = strchrnul(buf, '\n'), *name;
 295         struct net_device *dev = to_net_dev(d);
 296         struct dsa_port *cpu_dp = dev->dsa_ptr;
 297         size_t len = end - buf;
 298         int err;
 299
 300         /* Empty string passed */
 301         if (!len)
 302                 return -ENOPROTOOPT;
 303
 304         name = kstrndup(buf, len, GFP_KERNEL);
 305         if (!name)
 306                 return -ENOMEM;
 307
 308         old_tag_ops = cpu_dp->tag_ops;
 309         new_tag_ops = dsa_tag_driver_get_by_name(name);
 310         kfree(name);
 311         /* Bad tagger name? */
 312         if (IS_ERR(new_tag_ops))
 313                 return PTR_ERR(new_tag_ops);
 314
 315         if (new_tag_ops == old_tag_ops)
 316                 /* Drop the temporarily held duplicate reference, since
 317                  * the DSA switch tree uses this tagger.
 318                  */
 319                 goto out;
 320
 321         err = dsa_tree_change_tag_proto(cpu_dp->ds->dst, new_tag_ops,
 322                                         old_tag_ops);
 323         if (err) {
 324                 /* On failure the old tagger is restored, so we don't need the
 325                  * driver for the new one.
 326                  */
 327                 dsa_tag_driver_put(new_tag_ops);
 328                 return err;
 329         }
 330
 331         /* On success we no longer need the module for the old tagging protocol
 332          */
 333 out:
 334         dsa_tag_driver_put(old_tag_ops);
 335         return count;
 336 }
 337 static DEVICE_ATTR_RW(tagging);
 338
 339 static struct attribute *dsa_user_attrs[] = {
 340         &dev_attr_tagging.attr,
 341         NULL
 342 };
 343
 344 static const struct attribute_group dsa_group = {
 345         .name   = "dsa",
 346         .attrs  = dsa_user_attrs,
 347 };
 348
 349 static void dsa_conduit_reset_mtu(struct net_device *dev)
 350 {
 351         int err;
 352
 353         err = dev_set_mtu(dev, ETH_DATA_LEN);
 354         if (err)
 355                 netdev_dbg(dev,
 356                            "Unable to reset MTU to exclude DSA overheads\n");
 357 }
 358
 359 int dsa_conduit_setup(struct net_device *dev, struct dsa_port *cpu_dp)
 360 {
 361         const struct dsa_device_ops *tag_ops = cpu_dp->tag_ops;
 362         struct dsa_switch *ds = cpu_dp->ds;
 363         struct device_link *consumer_link;
 364         int mtu, ret;
 365
 366         mtu = ETH_DATA_LEN + dsa_tag_protocol_overhead(tag_ops);
 367
 368         /* The DSA conduit must use SET_NETDEV_DEV for this to work. */
 369         if (!netif_is_lag_master(dev)) {
 370                 consumer_link = device_link_add(ds->dev, dev->dev.parent,
 371                                                 DL_FLAG_AUTOREMOVE_CONSUMER);
 372                 if (!consumer_link)
 373                         netdev_err(dev,
 374                                    "Failed to create a device link to DSA switch %s\n",
 375                                    dev_name(ds->dev));
 376         }
 377
 378         /* The switch driver may not implement ->port_change_mtu(), case in
 379          * which dsa_user_change_mtu() will not update the conduit MTU either,
 380          * so we need to do that here.
 381          */
 382         ret = dev_set_mtu(dev, mtu);
 383         if (ret)
 384                 netdev_warn(dev, "error %d setting MTU to %d to include DSA overhead\n",
 385                             ret, mtu);
 386
 387         /* If we use a tagging format that doesn't have an ethertype
 388          * field, make sure that all packets from this point on get
 389          * sent to the tag format's receive function.
 390          */
 391         wmb();
 392
 393         dev->dsa_ptr = cpu_dp;
 394
 395         dsa_conduit_set_promiscuity(dev, 1);
 396
 397         ret = dsa_conduit_ethtool_setup(dev);
 398         if (ret)
 399                 goto out_err_reset_promisc;
 400
 401         ret = sysfs_create_group(&dev->dev.kobj, &dsa_group);
 402         if (ret)
 403                 goto out_err_ethtool_teardown;
 404
 405         return ret;
 406
 407 out_err_ethtool_teardown:
 408         dsa_conduit_ethtool_teardown(dev);
 409 out_err_reset_promisc:
 410         dsa_conduit_set_promiscuity(dev, -1);
 411         return ret;
 412 }
 413
 414 void dsa_conduit_teardown(struct net_device *dev)
 415 {
 416         sysfs_remove_group(&dev->dev.kobj, &dsa_group);
 417         dsa_conduit_ethtool_teardown(dev);
 418         dsa_conduit_reset_mtu(dev);
 419         dsa_conduit_set_promiscuity(dev, -1);
 420
 421         dev->dsa_ptr = NULL;
 422
 423         /* If we used a tagging format that doesn't have an ethertype
 424          * field, make sure that all packets from this point get sent
 425          * without the tag and go through the regular receive path.
 426          */
 427         wmb();
 428 }
 429
 430 int dsa_conduit_lag_setup(struct net_device *lag_dev, struct dsa_port *cpu_dp,
 431                           struct netdev_lag_upper_info *uinfo,
 432                           struct netlink_ext_ack *extack)
 433 {
 434         bool conduit_setup = false;
 435         int err;
 436
 437         if (!netdev_uses_dsa(lag_dev)) {
 438                 err = dsa_conduit_setup(lag_dev, cpu_dp);
 439                 if (err)
 440                         return err;
 441
 442                 conduit_setup = true;
 443         }
 444
 445         err = dsa_port_lag_join(cpu_dp, lag_dev, uinfo, extack);
 446         if (err) {
 447                 NL_SET_ERR_MSG_WEAK_MOD(extack, "CPU port failed to join LAG");
 448                 goto out_conduit_teardown;
 449         }
 450
 451         return 0;
 452
 453 out_conduit_teardown:
 454         if (conduit_setup)
 455                 dsa_conduit_teardown(lag_dev);
 456         return err;
 457 }
 458
 459 /* Tear down a conduit if there isn't any other user port on it,
 460  * optionally also destroying LAG information.
 461  */
 462 void dsa_conduit_lag_teardown(struct net_device *lag_dev,
 463                               struct dsa_port *cpu_dp)
 464 {
 465         struct net_device *upper;
 466         struct list_head *iter;
 467
 468         dsa_port_lag_leave(cpu_dp, lag_dev);
 469
 470         netdev_for_each_upper_dev_rcu(lag_dev, upper, iter)
 471                 if (dsa_user_dev_check(upper))
 472                         return;
 473
 474         dsa_conduit_teardown(lag_dev);
 475 }