1/* SPDX-License-Identifier: GPL-2.0 */ 2/* 3 * net/dst.h Protocol independent destination cache definitions. 4 * 5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 6 * 7 */ 8 9#ifndef _NET_DST_H 10#define _NET_DST_H 11 12#include <net/dst_ops.h> 13#include <linux/netdevice.h> 14#include <linux/rtnetlink.h> 15#include <linux/rcupdate.h> 16#include <linux/bug.h> 17#include <linux/jiffies.h> 18#include <linux/refcount.h> 19#include <linux/rcuref.h> 20#include <net/neighbour.h> 21#include <asm/processor.h> 22#include <linux/indirect_call_wrapper.h> 23 24struct sk_buff; 25 26struct dst_entry { 27 struct net_device *dev; 28 struct dst_ops *ops; 29 unsigned long _metrics; 30 unsigned long expires; 31#ifdef CONFIG_XFRM 32 struct xfrm_state *xfrm; 33#else 34 void *__pad1; 35#endif 36 int (*input)(struct sk_buff *); 37 int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb); 38 39 unsigned short flags; 40#define DST_NOXFRM 0x0002 41#define DST_NOPOLICY 0x0004 42#define DST_NOCOUNT 0x0008 43#define DST_FAKE_RTABLE 0x0010 44#define DST_XFRM_TUNNEL 0x0020 45#define DST_XFRM_QUEUE 0x0040 46#define DST_METADATA 0x0080 47 48 /* A non-zero value of dst->obsolete forces by-hand validation 49 * of the route entry. Positive values are set by the generic 50 * dst layer to indicate that the entry has been forcefully 51 * destroyed. 52 * 53 * Negative values are used by the implementation layer code to 54 * force invocation of the dst_ops->check() method. 55 */ 56 short obsolete; 57#define DST_OBSOLETE_NONE 0 58#define DST_OBSOLETE_DEAD 2 59#define DST_OBSOLETE_FORCE_CHK -1 60#define DST_OBSOLETE_KILL -2 61 unsigned short header_len; /* more space at head required */ 62 unsigned short trailer_len; /* space to reserve at tail */ 63 64 /* 65 * __rcuref wants to be on a different cache line from 66 * input/output/ops or performance tanks badly 67 */ 68#ifdef CONFIG_64BIT 69 rcuref_t __rcuref; /* 64-bit offset 64 */ 70#endif 71 int __use; 72 unsigned long lastuse; 73 struct rcu_head rcu_head; 74 short error; 75 short __pad; 76 __u32 tclassid; 77#ifndef CONFIG_64BIT 78 struct lwtunnel_state *lwtstate; 79 rcuref_t __rcuref; /* 32-bit offset 64 */ 80#endif 81 netdevice_tracker dev_tracker; 82 83 /* 84 * Used by rtable and rt6_info. Moves lwtstate into the next cache 85 * line on 64bit so that lwtstate does not cause false sharing with 86 * __rcuref under contention of __rcuref. This also puts the 87 * frequently accessed members of rtable and rt6_info out of the 88 * __rcuref cache line. 89 */ 90 struct list_head rt_uncached; 91 struct uncached_list *rt_uncached_list; 92#ifdef CONFIG_64BIT 93 struct lwtunnel_state *lwtstate; 94#endif 95}; 96 97struct dst_metrics { 98 u32 metrics[RTAX_MAX]; 99 refcount_t refcnt; 100} __aligned(4); /* Low pointer bits contain DST_METRICS_FLAGS */ 101extern const struct dst_metrics dst_default_metrics; 102 103u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old); 104 105#define DST_METRICS_READ_ONLY 0x1UL 106#define DST_METRICS_REFCOUNTED 0x2UL 107#define DST_METRICS_FLAGS 0x3UL 108#define __DST_METRICS_PTR(Y) \ 109 ((u32 *)((Y) & ~DST_METRICS_FLAGS)) 110#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics) 111 112static inline bool dst_metrics_read_only(const struct dst_entry *dst) 113{ 114 return dst->_metrics & DST_METRICS_READ_ONLY; 115} 116 117void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old); 118 119static inline void dst_destroy_metrics_generic(struct dst_entry *dst) 120{ 121 unsigned long val = dst->_metrics; 122 if (!(val & DST_METRICS_READ_ONLY)) 123 __dst_destroy_metrics_generic(dst, val); 124} 125 126static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst) 127{ 128 unsigned long p = dst->_metrics; 129 130 BUG_ON(!p); 131 132 if (p & DST_METRICS_READ_ONLY) 133 return dst->ops->cow_metrics(dst, p); 134 return __DST_METRICS_PTR(p); 135} 136 137/* This may only be invoked before the entry has reached global 138 * visibility. 139 */ 140static inline void dst_init_metrics(struct dst_entry *dst, 141 const u32 *src_metrics, 142 bool read_only) 143{ 144 dst->_metrics = ((unsigned long) src_metrics) | 145 (read_only ? DST_METRICS_READ_ONLY : 0); 146} 147 148static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src) 149{ 150 u32 *dst_metrics = dst_metrics_write_ptr(dest); 151 152 if (dst_metrics) { 153 u32 *src_metrics = DST_METRICS_PTR(src); 154 155 memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32)); 156 } 157} 158 159static inline u32 *dst_metrics_ptr(struct dst_entry *dst) 160{ 161 return DST_METRICS_PTR(dst); 162} 163 164static inline u32 165dst_metric_raw(const struct dst_entry *dst, const int metric) 166{ 167 u32 *p = DST_METRICS_PTR(dst); 168 169 return p[metric-1]; 170} 171 172static inline u32 173dst_metric(const struct dst_entry *dst, const int metric) 174{ 175 WARN_ON_ONCE(metric == RTAX_HOPLIMIT || 176 metric == RTAX_ADVMSS || 177 metric == RTAX_MTU); 178 return dst_metric_raw(dst, metric); 179} 180 181static inline u32 182dst_metric_advmss(const struct dst_entry *dst) 183{ 184 u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS); 185 186 if (!advmss) 187 advmss = dst->ops->default_advmss(dst); 188 189 return advmss; 190} 191 192static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val) 193{ 194 u32 *p = dst_metrics_write_ptr(dst); 195 196 if (p) 197 p[metric-1] = val; 198} 199 200/* Kernel-internal feature bits that are unallocated in user space. */ 201#define DST_FEATURE_ECN_CA (1U << 31) 202 203#define DST_FEATURE_MASK (DST_FEATURE_ECN_CA) 204#define DST_FEATURE_ECN_MASK (DST_FEATURE_ECN_CA | RTAX_FEATURE_ECN) 205 206static inline u32 207dst_feature(const struct dst_entry *dst, u32 feature) 208{ 209 return dst_metric(dst, RTAX_FEATURES) & feature; 210} 211 212INDIRECT_CALLABLE_DECLARE(unsigned int ip6_mtu(const struct dst_entry *)); 213INDIRECT_CALLABLE_DECLARE(unsigned int ipv4_mtu(const struct dst_entry *)); 214static inline u32 dst_mtu(const struct dst_entry *dst) 215{ 216 return INDIRECT_CALL_INET(dst->ops->mtu, ip6_mtu, ipv4_mtu, dst); 217} 218 219/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */ 220static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric) 221{ 222 return msecs_to_jiffies(dst_metric(dst, metric)); 223} 224 225static inline int 226dst_metric_locked(const struct dst_entry *dst, int metric) 227{ 228 return dst_metric(dst, RTAX_LOCK) & (1 << metric); 229} 230 231static inline void dst_hold(struct dst_entry *dst) 232{ 233 /* 234 * If your kernel compilation stops here, please check 235 * the placement of __rcuref in struct dst_entry 236 */ 237 BUILD_BUG_ON(offsetof(struct dst_entry, __rcuref) & 63); 238 WARN_ON(!rcuref_get(&dst->__rcuref)); 239} 240 241static inline void dst_use_noref(struct dst_entry *dst, unsigned long time) 242{ 243 if (unlikely(time != dst->lastuse)) { 244 dst->__use++; 245 dst->lastuse = time; 246 } 247} 248 249static inline struct dst_entry *dst_clone(struct dst_entry *dst) 250{ 251 if (dst) 252 dst_hold(dst); 253 return dst; 254} 255 256void dst_release(struct dst_entry *dst); 257 258void dst_release_immediate(struct dst_entry *dst); 259 260static inline void refdst_drop(unsigned long refdst) 261{ 262 if (!(refdst & SKB_DST_NOREF)) 263 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK)); 264} 265 266/** 267 * skb_dst_drop - drops skb dst 268 * @skb: buffer 269 * 270 * Drops dst reference count if a reference was taken. 271 */ 272static inline void skb_dst_drop(struct sk_buff *skb) 273{ 274 if (skb->_skb_refdst) { 275 refdst_drop(skb->_skb_refdst); 276 skb->_skb_refdst = 0UL; 277 } 278} 279 280static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst) 281{ 282 nskb->slow_gro |= !!refdst; 283 nskb->_skb_refdst = refdst; 284 if (!(nskb->_skb_refdst & SKB_DST_NOREF)) 285 dst_clone(skb_dst(nskb)); 286} 287 288static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb) 289{ 290 __skb_dst_copy(nskb, oskb->_skb_refdst); 291} 292 293/** 294 * dst_hold_safe - Take a reference on a dst if possible 295 * @dst: pointer to dst entry 296 * 297 * This helper returns false if it could not safely 298 * take a reference on a dst. 299 */ 300static inline bool dst_hold_safe(struct dst_entry *dst) 301{ 302 return rcuref_get(&dst->__rcuref); 303} 304 305/** 306 * skb_dst_force - makes sure skb dst is refcounted 307 * @skb: buffer 308 * 309 * If dst is not yet refcounted and not destroyed, grab a ref on it. 310 * Returns true if dst is refcounted. 311 */ 312static inline bool skb_dst_force(struct sk_buff *skb) 313{ 314 if (skb_dst_is_noref(skb)) { 315 struct dst_entry *dst = skb_dst(skb); 316 317 WARN_ON(!rcu_read_lock_held()); 318 if (!dst_hold_safe(dst)) 319 dst = NULL; 320 321 skb->_skb_refdst = (unsigned long)dst; 322 skb->slow_gro |= !!dst; 323 } 324 325 return skb->_skb_refdst != 0UL; 326} 327 328 329/** 330 * __skb_tunnel_rx - prepare skb for rx reinsert 331 * @skb: buffer 332 * @dev: tunnel device 333 * @net: netns for packet i/o 334 * 335 * After decapsulation, packet is going to re-enter (netif_rx()) our stack, 336 * so make some cleanups. (no accounting done) 337 */ 338static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev, 339 struct net *net) 340{ 341 skb->dev = dev; 342 343 /* 344 * Clear hash so that we can recalulate the hash for the 345 * encapsulated packet, unless we have already determine the hash 346 * over the L4 4-tuple. 347 */ 348 skb_clear_hash_if_not_l4(skb); 349 skb_set_queue_mapping(skb, 0); 350 skb_scrub_packet(skb, !net_eq(net, dev_net(dev))); 351} 352 353/** 354 * skb_tunnel_rx - prepare skb for rx reinsert 355 * @skb: buffer 356 * @dev: tunnel device 357 * @net: netns for packet i/o 358 * 359 * After decapsulation, packet is going to re-enter (netif_rx()) our stack, 360 * so make some cleanups, and perform accounting. 361 * Note: this accounting is not SMP safe. 362 */ 363static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev, 364 struct net *net) 365{ 366 DEV_STATS_INC(dev, rx_packets); 367 DEV_STATS_ADD(dev, rx_bytes, skb->len); 368 __skb_tunnel_rx(skb, dev, net); 369} 370 371static inline u32 dst_tclassid(const struct sk_buff *skb) 372{ 373#ifdef CONFIG_IP_ROUTE_CLASSID 374 const struct dst_entry *dst; 375 376 dst = skb_dst(skb); 377 if (dst) 378 return dst->tclassid; 379#endif 380 return 0; 381} 382 383int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb); 384static inline int dst_discard(struct sk_buff *skb) 385{ 386 return dst_discard_out(&init_net, skb->sk, skb); 387} 388void *dst_alloc(struct dst_ops *ops, struct net_device *dev, 389 int initial_obsolete, unsigned short flags); 390void dst_init(struct dst_entry *dst, struct dst_ops *ops, 391 struct net_device *dev, int initial_obsolete, 392 unsigned short flags); 393void dst_dev_put(struct dst_entry *dst); 394 395static inline void dst_confirm(struct dst_entry *dst) 396{ 397} 398 399static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr) 400{ 401 struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr); 402 return IS_ERR(n) ? NULL : n; 403} 404 405static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst, 406 struct sk_buff *skb) 407{ 408 struct neighbour *n; 409 410 if (WARN_ON_ONCE(!dst->ops->neigh_lookup)) 411 return NULL; 412 413 n = dst->ops->neigh_lookup(dst, skb, NULL); 414 415 return IS_ERR(n) ? NULL : n; 416} 417 418static inline void dst_confirm_neigh(const struct dst_entry *dst, 419 const void *daddr) 420{ 421 if (dst->ops->confirm_neigh) 422 dst->ops->confirm_neigh(dst, daddr); 423} 424 425static inline void dst_link_failure(struct sk_buff *skb) 426{ 427 struct dst_entry *dst = skb_dst(skb); 428 if (dst && dst->ops && dst->ops->link_failure) 429 dst->ops->link_failure(skb); 430} 431 432static inline void dst_set_expires(struct dst_entry *dst, int timeout) 433{ 434 unsigned long expires = jiffies + timeout; 435 436 if (expires == 0) 437 expires = 1; 438 439 if (dst->expires == 0 || time_before(expires, dst->expires)) 440 dst->expires = expires; 441} 442 443INDIRECT_CALLABLE_DECLARE(int ip6_output(struct net *, struct sock *, 444 struct sk_buff *)); 445INDIRECT_CALLABLE_DECLARE(int ip_output(struct net *, struct sock *, 446 struct sk_buff *)); 447/* Output packet to network from transport. */ 448static inline int dst_output(struct net *net, struct sock *sk, struct sk_buff *skb) 449{ 450 return INDIRECT_CALL_INET(skb_dst(skb)->output, 451 ip6_output, ip_output, 452 net, sk, skb); 453} 454 455INDIRECT_CALLABLE_DECLARE(int ip6_input(struct sk_buff *)); 456INDIRECT_CALLABLE_DECLARE(int ip_local_deliver(struct sk_buff *)); 457/* Input packet from network to transport. */ 458static inline int dst_input(struct sk_buff *skb) 459{ 460 return INDIRECT_CALL_INET(skb_dst(skb)->input, 461 ip6_input, ip_local_deliver, skb); 462} 463 464INDIRECT_CALLABLE_DECLARE(struct dst_entry *ip6_dst_check(struct dst_entry *, 465 u32)); 466INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *, 467 u32)); 468static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie) 469{ 470 if (dst->obsolete) 471 dst = INDIRECT_CALL_INET(dst->ops->check, ip6_dst_check, 472 ipv4_dst_check, dst, cookie); 473 return dst; 474} 475 476/* Flags for xfrm_lookup flags argument. */ 477enum { 478 XFRM_LOOKUP_ICMP = 1 << 0, 479 XFRM_LOOKUP_QUEUE = 1 << 1, 480 XFRM_LOOKUP_KEEP_DST_REF = 1 << 2, 481}; 482 483struct flowi; 484#ifndef CONFIG_XFRM 485static inline struct dst_entry *xfrm_lookup(struct net *net, 486 struct dst_entry *dst_orig, 487 const struct flowi *fl, 488 const struct sock *sk, 489 int flags) 490{ 491 return dst_orig; 492} 493 494static inline struct dst_entry * 495xfrm_lookup_with_ifid(struct net *net, struct dst_entry *dst_orig, 496 const struct flowi *fl, const struct sock *sk, 497 int flags, u32 if_id) 498{ 499 return dst_orig; 500} 501 502static inline struct dst_entry *xfrm_lookup_route(struct net *net, 503 struct dst_entry *dst_orig, 504 const struct flowi *fl, 505 const struct sock *sk, 506 int flags) 507{ 508 return dst_orig; 509} 510 511static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) 512{ 513 return NULL; 514} 515 516#else 517struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig, 518 const struct flowi *fl, const struct sock *sk, 519 int flags); 520 521struct dst_entry *xfrm_lookup_with_ifid(struct net *net, 522 struct dst_entry *dst_orig, 523 const struct flowi *fl, 524 const struct sock *sk, int flags, 525 u32 if_id); 526 527struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig, 528 const struct flowi *fl, const struct sock *sk, 529 int flags); 530 531/* skb attached with this dst needs transformation if dst->xfrm is valid */ 532static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) 533{ 534 return dst->xfrm; 535} 536#endif 537 538static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu) 539{ 540 struct dst_entry *dst = skb_dst(skb); 541 542 if (dst && dst->ops->update_pmtu) 543 dst->ops->update_pmtu(dst, NULL, skb, mtu, true); 544} 545 546/* update dst pmtu but not do neighbor confirm */ 547static inline void skb_dst_update_pmtu_no_confirm(struct sk_buff *skb, u32 mtu) 548{ 549 struct dst_entry *dst = skb_dst(skb); 550 551 if (dst && dst->ops->update_pmtu) 552 dst->ops->update_pmtu(dst, NULL, skb, mtu, false); 553} 554 555struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie); 556void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk, 557 struct sk_buff *skb, u32 mtu, bool confirm_neigh); 558void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk, 559 struct sk_buff *skb); 560u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old); 561struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst, 562 struct sk_buff *skb, 563 const void *daddr); 564unsigned int dst_blackhole_mtu(const struct dst_entry *dst); 565 566#endif /* _NET_DST_H */ 567