include/net/nexthop.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Generic nexthop implementation
   4  *
   5  * Copyright (c) 2017-19 Cumulus Networks
   6  * Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com>
   7  */
   8
   9 #ifndef __LINUX_NEXTHOP_H
  10 #define __LINUX_NEXTHOP_H
  11
  12 #include <linux/netdevice.h>
  13 #include <linux/notifier.h>
  14 #include <linux/route.h>
  15 #include <linux/types.h>
  16 #include <net/ip_fib.h>
  17 #include <net/ip6_fib.h>
  18 #include <net/netlink.h>
  19
  20 #define NEXTHOP_VALID_USER_FLAGS RTNH_F_ONLINK
  21
  22 struct nexthop;
  23
  24 struct nh_config {
  25         u32             nh_id;
  26
  27         u8              nh_family;
  28         u8              nh_protocol;
  29         u8              nh_blackhole;
  30         u8              nh_fdb;
  31         u32             nh_flags;
  32
  33         int             nh_ifindex;
  34         struct net_device *dev;
  35
  36         union {
  37                 __be32          ipv4;
  38                 struct in6_addr ipv6;
  39         } gw;
  40
  41         struct nlattr   *nh_grp;
  42         u16             nh_grp_type;
  43         u16             nh_grp_res_num_buckets;
  44         unsigned long   nh_grp_res_idle_timer;
  45         unsigned long   nh_grp_res_unbalanced_timer;
  46         bool            nh_grp_res_has_num_buckets;
  47         bool            nh_grp_res_has_idle_timer;
  48         bool            nh_grp_res_has_unbalanced_timer;
  49
  50         struct nlattr   *nh_encap;
  51         u16             nh_encap_type;
  52
  53         u32             nlflags;
  54         struct nl_info  nlinfo;
  55 };
  56
  57 struct nh_info {
  58         struct hlist_node       dev_hash;    /* entry on netns devhash */
  59         struct nexthop          *nh_parent;
  60
  61         u8                      family;
  62         bool                    reject_nh;
  63         bool                    fdb_nh;
  64
  65         union {
  66                 struct fib_nh_common    fib_nhc;
  67                 struct fib_nh           fib_nh;
  68                 struct fib6_nh          fib6_nh;
  69         };
  70 };
  71
  72 struct nh_res_bucket {
  73         struct nh_grp_entry __rcu *nh_entry;
  74         atomic_long_t           used_time;
  75         unsigned long           migrated_time;
  76         bool                    occupied;
  77         u8                      nh_flags;
  78 };
  79
  80 struct nh_res_table {
  81         struct net              *net;
  82         u32                     nhg_id;
  83         struct delayed_work     upkeep_dw;
  84
  85         /* List of NHGEs that have too few buckets ("uw" for underweight).
  86          * Reclaimed buckets will be given to entries in this list.
  87          */
  88         struct list_head        uw_nh_entries;
  89         unsigned long           unbalanced_since;
  90
  91         u32                     idle_timer;
  92         u32                     unbalanced_timer;
  93
  94         u16                     num_nh_buckets;
  95         struct nh_res_bucket    nh_buckets[];
  96 };
  97
  98 struct nh_grp_entry {
  99         struct nexthop  *nh;
 100         u8              weight;
 101
 102         union {
 103                 struct {
 104                         atomic_t        upper_bound;
 105                 } hthr;
 106                 struct {
 107                         /* Member on uw_nh_entries. */
 108                         struct list_head        uw_nh_entry;
 109
 110                         u16                     count_buckets;
 111                         u16                     wants_buckets;
 112                 } res;
 113         };
 114
 115         struct list_head nh_list;
 116         struct nexthop  *nh_parent;  /* nexthop of group with this entry */
 117 };
 118
 119 struct nh_group {
 120         struct nh_group         *spare; /* spare group for removals */
 121         u16                     num_nh;
 122         bool                    is_multipath;
 123         bool                    hash_threshold;
 124         bool                    resilient;
 125         bool                    fdb_nh;
 126         bool                    has_v4;
 127
 128         struct nh_res_table __rcu *res_table;
 129         struct nh_grp_entry     nh_entries[];
 130 };
 131
 132 struct nexthop {
 133         struct rb_node          rb_node;    /* entry on netns rbtree */
 134         struct list_head        fi_list;    /* v4 entries using nh */
 135         struct list_head        f6i_list;   /* v6 entries using nh */
 136         struct list_head        fdb_list;   /* fdb entries using this nh */
 137         struct list_head        grp_list;   /* nh group entries using this nh */
 138         struct net              *net;
 139
 140         u32                     id;
 141
 142         u8                      protocol;   /* app managing this nh */
 143         u8                      nh_flags;
 144         bool                    is_group;
 145
 146         refcount_t              refcnt;
 147         struct rcu_head         rcu;
 148
 149         union {
 150                 struct nh_info  __rcu *nh_info;
 151                 struct nh_group __rcu *nh_grp;
 152         };
 153 };
 154
 155 enum nexthop_event_type {
 156         NEXTHOP_EVENT_DEL,
 157         NEXTHOP_EVENT_REPLACE,
 158         NEXTHOP_EVENT_RES_TABLE_PRE_REPLACE,
 159         NEXTHOP_EVENT_BUCKET_REPLACE,
 160 };
 161
 162 enum nh_notifier_info_type {
 163         NH_NOTIFIER_INFO_TYPE_SINGLE,
 164         NH_NOTIFIER_INFO_TYPE_GRP,
 165         NH_NOTIFIER_INFO_TYPE_RES_TABLE,
 166         NH_NOTIFIER_INFO_TYPE_RES_BUCKET,
 167 };
 168
 169 struct nh_notifier_single_info {
 170         struct net_device *dev;
 171         u8 gw_family;
 172         union {
 173                 __be32 ipv4;
 174                 struct in6_addr ipv6;
 175         };
 176         u8 is_reject:1,
 177            is_fdb:1,
 178            has_encap:1;
 179 };
 180
 181 struct nh_notifier_grp_entry_info {
 182         u8 weight;
 183         u32 id;
 184         struct nh_notifier_single_info nh;
 185 };
 186
 187 struct nh_notifier_grp_info {
 188         u16 num_nh;
 189         bool is_fdb;
 190         struct nh_notifier_grp_entry_info nh_entries[];
 191 };
 192
 193 struct nh_notifier_res_bucket_info {
 194         u16 bucket_index;
 195         unsigned int idle_timer_ms;
 196         bool force;
 197         struct nh_notifier_single_info old_nh;
 198         struct nh_notifier_single_info new_nh;
 199 };
 200
 201 struct nh_notifier_res_table_info {
 202         u16 num_nh_buckets;
 203         struct nh_notifier_single_info nhs[];
 204 };
 205
 206 struct nh_notifier_info {
 207         struct net *net;
 208         struct netlink_ext_ack *extack;
 209         u32 id;
 210         enum nh_notifier_info_type type;
 211         union {
 212                 struct nh_notifier_single_info *nh;
 213                 struct nh_notifier_grp_info *nh_grp;
 214                 struct nh_notifier_res_table_info *nh_res_table;
 215                 struct nh_notifier_res_bucket_info *nh_res_bucket;
 216         };
 217 };
 218
 219 int register_nexthop_notifier(struct net *net, struct notifier_block *nb,
 220                               struct netlink_ext_ack *extack);
 221 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb);
 222 void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap);
 223 void nexthop_bucket_set_hw_flags(struct net *net, u32 id, u16 bucket_index,
 224                                  bool offload, bool trap);
 225 void nexthop_res_grp_activity_update(struct net *net, u32 id, u16 num_buckets,
 226                                      unsigned long *activity);
 227
 228 /* caller is holding rcu or rtnl; no reference taken to nexthop */
 229 struct nexthop *nexthop_find_by_id(struct net *net, u32 id);
 230 void nexthop_free_rcu(struct rcu_head *head);
 231
 232 static inline bool nexthop_get(struct nexthop *nh)
 233 {
 234         return refcount_inc_not_zero(&nh->refcnt);
 235 }
 236
 237 static inline void nexthop_put(struct nexthop *nh)
 238 {
 239         if (refcount_dec_and_test(&nh->refcnt))
 240                 call_rcu(&nh->rcu, nexthop_free_rcu);
 241 }
 242
 243 static inline bool nexthop_cmp(const struct nexthop *nh1,
 244                                const struct nexthop *nh2)
 245 {
 246         return nh1 == nh2;
 247 }
 248
 249 static inline bool nexthop_is_fdb(const struct nexthop *nh)
 250 {
 251         if (nh->is_group) {
 252                 const struct nh_group *nh_grp;
 253
 254                 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
 255                 return nh_grp->fdb_nh;
 256         } else {
 257                 const struct nh_info *nhi;
 258
 259                 nhi = rcu_dereference_rtnl(nh->nh_info);
 260                 return nhi->fdb_nh;
 261         }
 262 }
 263
 264 static inline bool nexthop_has_v4(const struct nexthop *nh)
 265 {
 266         if (nh->is_group) {
 267                 struct nh_group *nh_grp;
 268
 269                 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
 270                 return nh_grp->has_v4;
 271         }
 272         return false;
 273 }
 274
 275 static inline bool nexthop_is_multipath(const struct nexthop *nh)
 276 {
 277         if (nh->is_group) {
 278                 struct nh_group *nh_grp;
 279
 280                 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
 281                 return nh_grp->is_multipath;
 282         }
 283         return false;
 284 }
 285
 286 struct nexthop *nexthop_select_path(struct nexthop *nh, int hash);
 287
 288 static inline unsigned int nexthop_num_path(const struct nexthop *nh)
 289 {
 290         unsigned int rc = 1;
 291
 292         if (nh->is_group) {
 293                 struct nh_group *nh_grp;
 294
 295                 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
 296                 if (nh_grp->is_multipath)
 297                         rc = nh_grp->num_nh;
 298         }
 299
 300         return rc;
 301 }
 302
 303 static inline
 304 struct nexthop *nexthop_mpath_select(const struct nh_group *nhg, int nhsel)
 305 {
 306         /* for_nexthops macros in fib_semantics.c grabs a pointer to
 307          * the nexthop before checking nhsel
 308          */
 309         if (nhsel >= nhg->num_nh)
 310                 return NULL;
 311
 312         return nhg->nh_entries[nhsel].nh;
 313 }
 314
 315 static inline
 316 int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh,
 317                             u8 rt_family)
 318 {
 319         struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
 320         int i;
 321
 322         for (i = 0; i < nhg->num_nh; i++) {
 323                 struct nexthop *nhe = nhg->nh_entries[i].nh;
 324                 struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info);
 325                 struct fib_nh_common *nhc = &nhi->fib_nhc;
 326                 int weight = nhg->nh_entries[i].weight;
 327
 328                 if (fib_add_nexthop(skb, nhc, weight, rt_family) < 0)
 329                         return -EMSGSIZE;
 330         }
 331
 332         return 0;
 333 }
 334
 335 /* called with rcu lock */
 336 static inline bool nexthop_is_blackhole(const struct nexthop *nh)
 337 {
 338         const struct nh_info *nhi;
 339
 340         if (nh->is_group) {
 341                 struct nh_group *nh_grp;
 342
 343                 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
 344                 if (nh_grp->num_nh > 1)
 345                         return false;
 346
 347                 nh = nh_grp->nh_entries[0].nh;
 348         }
 349
 350         nhi = rcu_dereference_rtnl(nh->nh_info);
 351         return nhi->reject_nh;
 352 }
 353
 354 static inline void nexthop_path_fib_result(struct fib_result *res, int hash)
 355 {
 356         struct nh_info *nhi;
 357         struct nexthop *nh;
 358
 359         nh = nexthop_select_path(res->fi->nh, hash);
 360         nhi = rcu_dereference(nh->nh_info);
 361         res->nhc = &nhi->fib_nhc;
 362 }
 363
 364 /* called with rcu read lock or rtnl held */
 365 static inline
 366 struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel)
 367 {
 368         struct nh_info *nhi;
 369
 370         BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0);
 371         BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
 372
 373         if (nh->is_group) {
 374                 struct nh_group *nh_grp;
 375
 376                 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
 377                 if (nh_grp->is_multipath) {
 378                         nh = nexthop_mpath_select(nh_grp, nhsel);
 379                         if (!nh)
 380                                 return NULL;
 381                 }
 382         }
 383
 384         nhi = rcu_dereference_rtnl(nh->nh_info);
 385         return &nhi->fib_nhc;
 386 }
 387
 388 /* called from fib_table_lookup with rcu_lock */
 389 static inline
 390 struct fib_nh_common *nexthop_get_nhc_lookup(const struct nexthop *nh,
 391                                              int fib_flags,
 392                                              const struct flowi4 *flp,
 393                                              int *nhsel)
 394 {
 395         struct nh_info *nhi;
 396
 397         if (nh->is_group) {
 398                 struct nh_group *nhg = rcu_dereference(nh->nh_grp);
 399                 int i;
 400
 401                 for (i = 0; i < nhg->num_nh; i++) {
 402                         struct nexthop *nhe = nhg->nh_entries[i].nh;
 403
 404                         nhi = rcu_dereference(nhe->nh_info);
 405                         if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
 406                                 *nhsel = i;
 407                                 return &nhi->fib_nhc;
 408                         }
 409                 }
 410         } else {
 411                 nhi = rcu_dereference(nh->nh_info);
 412                 if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) {
 413                         *nhsel = 0;
 414                         return &nhi->fib_nhc;
 415                 }
 416         }
 417
 418         return NULL;
 419 }
 420
 421 static inline bool nexthop_uses_dev(const struct nexthop *nh,
 422                                     const struct net_device *dev)
 423 {
 424         struct nh_info *nhi;
 425
 426         if (nh->is_group) {
 427                 struct nh_group *nhg = rcu_dereference(nh->nh_grp);
 428                 int i;
 429
 430                 for (i = 0; i < nhg->num_nh; i++) {
 431                         struct nexthop *nhe = nhg->nh_entries[i].nh;
 432
 433                         nhi = rcu_dereference(nhe->nh_info);
 434                         if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
 435                                 return true;
 436                 }
 437         } else {
 438                 nhi = rcu_dereference(nh->nh_info);
 439                 if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev))
 440                         return true;
 441         }
 442
 443         return false;
 444 }
 445
 446 static inline unsigned int fib_info_num_path(const struct fib_info *fi)
 447 {
 448         if (unlikely(fi->nh))
 449                 return nexthop_num_path(fi->nh);
 450
 451         return fi->fib_nhs;
 452 }
 453
 454 int fib_check_nexthop(struct nexthop *nh, u8 scope,
 455                       struct netlink_ext_ack *extack);
 456
 457 static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel)
 458 {
 459         if (unlikely(fi->nh))
 460                 return nexthop_fib_nhc(fi->nh, nhsel);
 461
 462         return &fi->fib_nh[nhsel].nh_common;
 463 }
 464
 465 /* only used when fib_nh is built into fib_info */
 466 static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel)
 467 {
 468         WARN_ON(fi->nh);
 469
 470         return &fi->fib_nh[nhsel];
 471 }
 472
 473 /*
 474  * IPv6 variants
 475  */
 476 int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
 477                        struct netlink_ext_ack *extack);
 478
 479 /* Caller should either hold rcu_read_lock(), or RTNL. */
 480 static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh)
 481 {
 482         struct nh_info *nhi;
 483
 484         if (nh->is_group) {
 485                 struct nh_group *nh_grp;
 486
 487                 nh_grp = rcu_dereference_rtnl(nh->nh_grp);
 488                 nh = nexthop_mpath_select(nh_grp, 0);
 489                 if (!nh)
 490                         return NULL;
 491         }
 492
 493         nhi = rcu_dereference_rtnl(nh->nh_info);
 494         if (nhi->family == AF_INET6)
 495                 return &nhi->fib6_nh;
 496
 497         return NULL;
 498 }
 499
 500 /* Variant of nexthop_fib6_nh().
 501  * Caller should either hold rcu_read_lock_bh(), or RTNL.
 502  */
 503 static inline struct fib6_nh *nexthop_fib6_nh_bh(struct nexthop *nh)
 504 {
 505         struct nh_info *nhi;
 506
 507         if (nh->is_group) {
 508                 struct nh_group *nh_grp;
 509
 510                 nh_grp = rcu_dereference_bh_rtnl(nh->nh_grp);
 511                 nh = nexthop_mpath_select(nh_grp, 0);
 512                 if (!nh)
 513                         return NULL;
 514         }
 515
 516         nhi = rcu_dereference_bh_rtnl(nh->nh_info);
 517         if (nhi->family == AF_INET6)
 518                 return &nhi->fib6_nh;
 519
 520         return NULL;
 521 }
 522
 523 static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i)
 524 {
 525         struct fib6_nh *fib6_nh;
 526
 527         fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh;
 528         return fib6_nh->fib_nh_dev;
 529 }
 530
 531 static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash)
 532 {
 533         struct nexthop *nh = res->f6i->nh;
 534         struct nh_info *nhi;
 535
 536         nh = nexthop_select_path(nh, hash);
 537
 538         nhi = rcu_dereference_rtnl(nh->nh_info);
 539         if (nhi->reject_nh) {
 540                 res->fib6_type = RTN_BLACKHOLE;
 541                 res->fib6_flags |= RTF_REJECT;
 542                 res->nh = nexthop_fib6_nh(nh);
 543         } else {
 544                 res->nh = &nhi->fib6_nh;
 545         }
 546 }
 547
 548 int nexthop_for_each_fib6_nh(struct nexthop *nh,
 549                              int (*cb)(struct fib6_nh *nh, void *arg),
 550                              void *arg);
 551
 552 static inline int nexthop_get_family(struct nexthop *nh)
 553 {
 554         struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
 555
 556         return nhi->family;
 557 }
 558
 559 static inline
 560 struct fib_nh_common *nexthop_fdb_nhc(struct nexthop *nh)
 561 {
 562         struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info);
 563
 564         return &nhi->fib_nhc;
 565 }
 566
 567 static inline struct fib_nh_common *nexthop_path_fdb_result(struct nexthop *nh,
 568                                                             int hash)
 569 {
 570         struct nh_info *nhi;
 571         struct nexthop *nhp;
 572
 573         nhp = nexthop_select_path(nh, hash);
 574         if (unlikely(!nhp))
 575                 return NULL;
 576         nhi = rcu_dereference(nhp->nh_info);
 577         return &nhi->fib_nhc;
 578 }
 579 #endif