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 44 struct nlattr *nh_encap; 45 u16 nh_encap_type; 46 47 u32 nlflags; 48 struct nl_info nlinfo; 49 }; 50 51 struct nh_info { 52 struct hlist_node dev_hash; /* entry on netns devhash */ 53 struct nexthop *nh_parent; 54 55 u8 family; 56 bool reject_nh; 57 bool fdb_nh; 58 59 union { 60 struct fib_nh_common fib_nhc; 61 struct fib_nh fib_nh; 62 struct fib6_nh fib6_nh; 63 }; 64 }; 65 66 struct nh_grp_entry { 67 struct nexthop *nh; 68 u8 weight; 69 70 union { 71 struct { 72 atomic_t upper_bound; 73 } mpath; 74 }; 75 76 struct list_head nh_list; 77 struct nexthop *nh_parent; /* nexthop of group with this entry */ 78 }; 79 80 struct nh_group { 81 struct nh_group *spare; /* spare group for removals */ 82 u16 num_nh; 83 bool mpath; 84 bool fdb_nh; 85 bool has_v4; 86 struct nh_grp_entry nh_entries[]; 87 }; 88 89 struct nexthop { 90 struct rb_node rb_node; /* entry on netns rbtree */ 91 struct list_head fi_list; /* v4 entries using nh */ 92 struct list_head f6i_list; /* v6 entries using nh */ 93 struct list_head fdb_list; /* fdb entries using this nh */ 94 struct list_head grp_list; /* nh group entries using this nh */ 95 struct net *net; 96 97 u32 id; 98 99 u8 protocol; /* app managing this nh */ 100 u8 nh_flags; 101 bool is_group; 102 103 refcount_t refcnt; 104 struct rcu_head rcu; 105 106 union { 107 struct nh_info __rcu *nh_info; 108 struct nh_group __rcu *nh_grp; 109 }; 110 }; 111 112 enum nexthop_event_type { 113 NEXTHOP_EVENT_DEL, 114 NEXTHOP_EVENT_REPLACE, 115 }; 116 117 enum nh_notifier_info_type { 118 NH_NOTIFIER_INFO_TYPE_SINGLE, 119 NH_NOTIFIER_INFO_TYPE_GRP, 120 }; 121 122 struct nh_notifier_single_info { 123 struct net_device *dev; 124 u8 gw_family; 125 union { 126 __be32 ipv4; 127 struct in6_addr ipv6; 128 }; 129 u8 is_reject:1, 130 is_fdb:1, 131 has_encap:1; 132 }; 133 134 struct nh_notifier_grp_entry_info { 135 u8 weight; 136 u32 id; 137 struct nh_notifier_single_info nh; 138 }; 139 140 struct nh_notifier_grp_info { 141 u16 num_nh; 142 bool is_fdb; 143 struct nh_notifier_grp_entry_info nh_entries[]; 144 }; 145 146 struct nh_notifier_info { 147 struct net *net; 148 struct netlink_ext_ack *extack; 149 u32 id; 150 enum nh_notifier_info_type type; 151 union { 152 struct nh_notifier_single_info *nh; 153 struct nh_notifier_grp_info *nh_grp; 154 }; 155 }; 156 157 int register_nexthop_notifier(struct net *net, struct notifier_block *nb, 158 struct netlink_ext_ack *extack); 159 int unregister_nexthop_notifier(struct net *net, struct notifier_block *nb); 160 void nexthop_set_hw_flags(struct net *net, u32 id, bool offload, bool trap); 161 162 /* caller is holding rcu or rtnl; no reference taken to nexthop */ 163 struct nexthop *nexthop_find_by_id(struct net *net, u32 id); 164 void nexthop_free_rcu(struct rcu_head *head); 165 166 static inline bool nexthop_get(struct nexthop *nh) 167 { 168 return refcount_inc_not_zero(&nh->refcnt); 169 } 170 171 static inline void nexthop_put(struct nexthop *nh) 172 { 173 if (refcount_dec_and_test(&nh->refcnt)) 174 call_rcu(&nh->rcu, nexthop_free_rcu); 175 } 176 177 static inline bool nexthop_cmp(const struct nexthop *nh1, 178 const struct nexthop *nh2) 179 { 180 return nh1 == nh2; 181 } 182 183 static inline bool nexthop_is_fdb(const struct nexthop *nh) 184 { 185 if (nh->is_group) { 186 const struct nh_group *nh_grp; 187 188 nh_grp = rcu_dereference_rtnl(nh->nh_grp); 189 return nh_grp->fdb_nh; 190 } else { 191 const struct nh_info *nhi; 192 193 nhi = rcu_dereference_rtnl(nh->nh_info); 194 return nhi->fdb_nh; 195 } 196 } 197 198 static inline bool nexthop_has_v4(const struct nexthop *nh) 199 { 200 if (nh->is_group) { 201 struct nh_group *nh_grp; 202 203 nh_grp = rcu_dereference_rtnl(nh->nh_grp); 204 return nh_grp->has_v4; 205 } 206 return false; 207 } 208 209 static inline bool nexthop_is_multipath(const struct nexthop *nh) 210 { 211 if (nh->is_group) { 212 struct nh_group *nh_grp; 213 214 nh_grp = rcu_dereference_rtnl(nh->nh_grp); 215 return nh_grp->mpath; 216 } 217 return false; 218 } 219 220 struct nexthop *nexthop_select_path(struct nexthop *nh, int hash); 221 222 static inline unsigned int nexthop_num_path(const struct nexthop *nh) 223 { 224 unsigned int rc = 1; 225 226 if (nh->is_group) { 227 struct nh_group *nh_grp; 228 229 nh_grp = rcu_dereference_rtnl(nh->nh_grp); 230 if (nh_grp->mpath) 231 rc = nh_grp->num_nh; 232 } 233 234 return rc; 235 } 236 237 static inline 238 struct nexthop *nexthop_mpath_select(const struct nh_group *nhg, int nhsel) 239 { 240 /* for_nexthops macros in fib_semantics.c grabs a pointer to 241 * the nexthop before checking nhsel 242 */ 243 if (nhsel >= nhg->num_nh) 244 return NULL; 245 246 return nhg->nh_entries[nhsel].nh; 247 } 248 249 static inline 250 int nexthop_mpath_fill_node(struct sk_buff *skb, struct nexthop *nh, 251 u8 rt_family) 252 { 253 struct nh_group *nhg = rtnl_dereference(nh->nh_grp); 254 int i; 255 256 for (i = 0; i < nhg->num_nh; i++) { 257 struct nexthop *nhe = nhg->nh_entries[i].nh; 258 struct nh_info *nhi = rcu_dereference_rtnl(nhe->nh_info); 259 struct fib_nh_common *nhc = &nhi->fib_nhc; 260 int weight = nhg->nh_entries[i].weight; 261 262 if (fib_add_nexthop(skb, nhc, weight, rt_family) < 0) 263 return -EMSGSIZE; 264 } 265 266 return 0; 267 } 268 269 /* called with rcu lock */ 270 static inline bool nexthop_is_blackhole(const struct nexthop *nh) 271 { 272 const struct nh_info *nhi; 273 274 if (nh->is_group) { 275 struct nh_group *nh_grp; 276 277 nh_grp = rcu_dereference_rtnl(nh->nh_grp); 278 if (nh_grp->num_nh > 1) 279 return false; 280 281 nh = nh_grp->nh_entries[0].nh; 282 } 283 284 nhi = rcu_dereference_rtnl(nh->nh_info); 285 return nhi->reject_nh; 286 } 287 288 static inline void nexthop_path_fib_result(struct fib_result *res, int hash) 289 { 290 struct nh_info *nhi; 291 struct nexthop *nh; 292 293 nh = nexthop_select_path(res->fi->nh, hash); 294 nhi = rcu_dereference(nh->nh_info); 295 res->nhc = &nhi->fib_nhc; 296 } 297 298 /* called with rcu read lock or rtnl held */ 299 static inline 300 struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel) 301 { 302 struct nh_info *nhi; 303 304 BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0); 305 BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0); 306 307 if (nh->is_group) { 308 struct nh_group *nh_grp; 309 310 nh_grp = rcu_dereference_rtnl(nh->nh_grp); 311 if (nh_grp->mpath) { 312 nh = nexthop_mpath_select(nh_grp, nhsel); 313 if (!nh) 314 return NULL; 315 } 316 } 317 318 nhi = rcu_dereference_rtnl(nh->nh_info); 319 return &nhi->fib_nhc; 320 } 321 322 /* called from fib_table_lookup with rcu_lock */ 323 static inline 324 struct fib_nh_common *nexthop_get_nhc_lookup(const struct nexthop *nh, 325 int fib_flags, 326 const struct flowi4 *flp, 327 int *nhsel) 328 { 329 struct nh_info *nhi; 330 331 if (nh->is_group) { 332 struct nh_group *nhg = rcu_dereference(nh->nh_grp); 333 int i; 334 335 for (i = 0; i < nhg->num_nh; i++) { 336 struct nexthop *nhe = nhg->nh_entries[i].nh; 337 338 nhi = rcu_dereference(nhe->nh_info); 339 if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) { 340 *nhsel = i; 341 return &nhi->fib_nhc; 342 } 343 } 344 } else { 345 nhi = rcu_dereference(nh->nh_info); 346 if (fib_lookup_good_nhc(&nhi->fib_nhc, fib_flags, flp)) { 347 *nhsel = 0; 348 return &nhi->fib_nhc; 349 } 350 } 351 352 return NULL; 353 } 354 355 static inline bool nexthop_uses_dev(const struct nexthop *nh, 356 const struct net_device *dev) 357 { 358 struct nh_info *nhi; 359 360 if (nh->is_group) { 361 struct nh_group *nhg = rcu_dereference(nh->nh_grp); 362 int i; 363 364 for (i = 0; i < nhg->num_nh; i++) { 365 struct nexthop *nhe = nhg->nh_entries[i].nh; 366 367 nhi = rcu_dereference(nhe->nh_info); 368 if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev)) 369 return true; 370 } 371 } else { 372 nhi = rcu_dereference(nh->nh_info); 373 if (nhc_l3mdev_matches_dev(&nhi->fib_nhc, dev)) 374 return true; 375 } 376 377 return false; 378 } 379 380 static inline unsigned int fib_info_num_path(const struct fib_info *fi) 381 { 382 if (unlikely(fi->nh)) 383 return nexthop_num_path(fi->nh); 384 385 return fi->fib_nhs; 386 } 387 388 int fib_check_nexthop(struct nexthop *nh, u8 scope, 389 struct netlink_ext_ack *extack); 390 391 static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel) 392 { 393 if (unlikely(fi->nh)) 394 return nexthop_fib_nhc(fi->nh, nhsel); 395 396 return &fi->fib_nh[nhsel].nh_common; 397 } 398 399 /* only used when fib_nh is built into fib_info */ 400 static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel) 401 { 402 WARN_ON(fi->nh); 403 404 return &fi->fib_nh[nhsel]; 405 } 406 407 /* 408 * IPv6 variants 409 */ 410 int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg, 411 struct netlink_ext_ack *extack); 412 413 static inline struct fib6_nh *nexthop_fib6_nh(struct nexthop *nh) 414 { 415 struct nh_info *nhi; 416 417 if (nh->is_group) { 418 struct nh_group *nh_grp; 419 420 nh_grp = rcu_dereference_rtnl(nh->nh_grp); 421 nh = nexthop_mpath_select(nh_grp, 0); 422 if (!nh) 423 return NULL; 424 } 425 426 nhi = rcu_dereference_rtnl(nh->nh_info); 427 if (nhi->family == AF_INET6) 428 return &nhi->fib6_nh; 429 430 return NULL; 431 } 432 433 static inline struct net_device *fib6_info_nh_dev(struct fib6_info *f6i) 434 { 435 struct fib6_nh *fib6_nh; 436 437 fib6_nh = f6i->nh ? nexthop_fib6_nh(f6i->nh) : f6i->fib6_nh; 438 return fib6_nh->fib_nh_dev; 439 } 440 441 static inline void nexthop_path_fib6_result(struct fib6_result *res, int hash) 442 { 443 struct nexthop *nh = res->f6i->nh; 444 struct nh_info *nhi; 445 446 nh = nexthop_select_path(nh, hash); 447 448 nhi = rcu_dereference_rtnl(nh->nh_info); 449 if (nhi->reject_nh) { 450 res->fib6_type = RTN_BLACKHOLE; 451 res->fib6_flags |= RTF_REJECT; 452 res->nh = nexthop_fib6_nh(nh); 453 } else { 454 res->nh = &nhi->fib6_nh; 455 } 456 } 457 458 int nexthop_for_each_fib6_nh(struct nexthop *nh, 459 int (*cb)(struct fib6_nh *nh, void *arg), 460 void *arg); 461 462 static inline int nexthop_get_family(struct nexthop *nh) 463 { 464 struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info); 465 466 return nhi->family; 467 } 468 469 static inline 470 struct fib_nh_common *nexthop_fdb_nhc(struct nexthop *nh) 471 { 472 struct nh_info *nhi = rcu_dereference_rtnl(nh->nh_info); 473 474 return &nhi->fib_nhc; 475 } 476 477 static inline struct fib_nh_common *nexthop_path_fdb_result(struct nexthop *nh, 478 int hash) 479 { 480 struct nh_info *nhi; 481 struct nexthop *nhp; 482 483 nhp = nexthop_select_path(nh, hash); 484 if (unlikely(!nhp)) 485 return NULL; 486 nhi = rcu_dereference(nhp->nh_info); 487 return &nhi->fib_nhc; 488 } 489 #endif 490