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