1 /* 2 * net/dst.h Protocol independent destination cache definitions. 3 * 4 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 5 * 6 */ 7 8 #ifndef _NET_DST_H 9 #define _NET_DST_H 10 11 #include <net/dst_ops.h> 12 #include <linux/netdevice.h> 13 #include <linux/rtnetlink.h> 14 #include <linux/rcupdate.h> 15 #include <linux/bug.h> 16 #include <linux/jiffies.h> 17 #include <net/neighbour.h> 18 #include <asm/processor.h> 19 20 #define DST_GC_MIN (HZ/10) 21 #define DST_GC_INC (HZ/2) 22 #define DST_GC_MAX (120*HZ) 23 24 /* Each dst_entry has reference count and sits in some parent list(s). 25 * When it is removed from parent list, it is "freed" (dst_free). 26 * After this it enters dead state (dst->obsolete > 0) and if its refcnt 27 * is zero, it can be destroyed immediately, otherwise it is added 28 * to gc list and garbage collector periodically checks the refcnt. 29 */ 30 31 struct sk_buff; 32 33 struct dst_entry { 34 struct rcu_head rcu_head; 35 struct dst_entry *child; 36 struct net_device *dev; 37 struct dst_ops *ops; 38 unsigned long _metrics; 39 unsigned long expires; 40 struct dst_entry *path; 41 struct dst_entry *from; 42 #ifdef CONFIG_XFRM 43 struct xfrm_state *xfrm; 44 #else 45 void *__pad1; 46 #endif 47 int (*input)(struct sk_buff *); 48 int (*output)(struct sock *sk, struct sk_buff *skb); 49 50 unsigned short flags; 51 #define DST_HOST 0x0001 52 #define DST_NOXFRM 0x0002 53 #define DST_NOPOLICY 0x0004 54 #define DST_NOHASH 0x0008 55 #define DST_NOCACHE 0x0010 56 #define DST_NOCOUNT 0x0020 57 #define DST_FAKE_RTABLE 0x0040 58 #define DST_XFRM_TUNNEL 0x0080 59 #define DST_XFRM_QUEUE 0x0100 60 #define DST_METADATA 0x0200 61 62 unsigned short pending_confirm; 63 64 short error; 65 66 /* A non-zero value of dst->obsolete forces by-hand validation 67 * of the route entry. Positive values are set by the generic 68 * dst layer to indicate that the entry has been forcefully 69 * destroyed. 70 * 71 * Negative values are used by the implementation layer code to 72 * force invocation of the dst_ops->check() method. 73 */ 74 short obsolete; 75 #define DST_OBSOLETE_NONE 0 76 #define DST_OBSOLETE_DEAD 2 77 #define DST_OBSOLETE_FORCE_CHK -1 78 #define DST_OBSOLETE_KILL -2 79 unsigned short header_len; /* more space at head required */ 80 unsigned short trailer_len; /* space to reserve at tail */ 81 #ifdef CONFIG_IP_ROUTE_CLASSID 82 __u32 tclassid; 83 #else 84 __u32 __pad2; 85 #endif 86 87 /* 88 * Align __refcnt to a 64 bytes alignment 89 * (L1_CACHE_SIZE would be too much) 90 */ 91 #ifdef CONFIG_64BIT 92 long __pad_to_align_refcnt[2]; 93 #endif 94 /* 95 * __refcnt wants to be on a different cache line from 96 * input/output/ops or performance tanks badly 97 */ 98 atomic_t __refcnt; /* client references */ 99 int __use; 100 unsigned long lastuse; 101 union { 102 struct dst_entry *next; 103 struct rtable __rcu *rt_next; 104 struct rt6_info *rt6_next; 105 struct dn_route __rcu *dn_next; 106 }; 107 }; 108 109 u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old); 110 extern const u32 dst_default_metrics[]; 111 112 #define DST_METRICS_READ_ONLY 0x1UL 113 #define DST_METRICS_FLAGS 0x3UL 114 #define __DST_METRICS_PTR(Y) \ 115 ((u32 *)((Y) & ~DST_METRICS_FLAGS)) 116 #define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics) 117 118 static inline bool dst_metrics_read_only(const struct dst_entry *dst) 119 { 120 return dst->_metrics & DST_METRICS_READ_ONLY; 121 } 122 123 void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old); 124 125 static inline void dst_destroy_metrics_generic(struct dst_entry *dst) 126 { 127 unsigned long val = dst->_metrics; 128 if (!(val & DST_METRICS_READ_ONLY)) 129 __dst_destroy_metrics_generic(dst, val); 130 } 131 132 static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst) 133 { 134 unsigned long p = dst->_metrics; 135 136 BUG_ON(!p); 137 138 if (p & DST_METRICS_READ_ONLY) 139 return dst->ops->cow_metrics(dst, p); 140 return __DST_METRICS_PTR(p); 141 } 142 143 /* This may only be invoked before the entry has reached global 144 * visibility. 145 */ 146 static inline void dst_init_metrics(struct dst_entry *dst, 147 const u32 *src_metrics, 148 bool read_only) 149 { 150 dst->_metrics = ((unsigned long) src_metrics) | 151 (read_only ? DST_METRICS_READ_ONLY : 0); 152 } 153 154 static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src) 155 { 156 u32 *dst_metrics = dst_metrics_write_ptr(dest); 157 158 if (dst_metrics) { 159 u32 *src_metrics = DST_METRICS_PTR(src); 160 161 memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32)); 162 } 163 } 164 165 static inline u32 *dst_metrics_ptr(struct dst_entry *dst) 166 { 167 return DST_METRICS_PTR(dst); 168 } 169 170 static inline u32 171 dst_metric_raw(const struct dst_entry *dst, const int metric) 172 { 173 u32 *p = DST_METRICS_PTR(dst); 174 175 return p[metric-1]; 176 } 177 178 static inline u32 179 dst_metric(const struct dst_entry *dst, const int metric) 180 { 181 WARN_ON_ONCE(metric == RTAX_HOPLIMIT || 182 metric == RTAX_ADVMSS || 183 metric == RTAX_MTU); 184 return dst_metric_raw(dst, metric); 185 } 186 187 static inline u32 188 dst_metric_advmss(const struct dst_entry *dst) 189 { 190 u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS); 191 192 if (!advmss) 193 advmss = dst->ops->default_advmss(dst); 194 195 return advmss; 196 } 197 198 static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val) 199 { 200 u32 *p = dst_metrics_write_ptr(dst); 201 202 if (p) 203 p[metric-1] = val; 204 } 205 206 static inline u32 207 dst_feature(const struct dst_entry *dst, u32 feature) 208 { 209 return dst_metric(dst, RTAX_FEATURES) & feature; 210 } 211 212 static inline u32 dst_mtu(const struct dst_entry *dst) 213 { 214 return dst->ops->mtu(dst); 215 } 216 217 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */ 218 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric) 219 { 220 return msecs_to_jiffies(dst_metric(dst, metric)); 221 } 222 223 static inline u32 224 dst_allfrag(const struct dst_entry *dst) 225 { 226 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG); 227 return ret; 228 } 229 230 static inline int 231 dst_metric_locked(const struct dst_entry *dst, int metric) 232 { 233 return dst_metric(dst, RTAX_LOCK) & (1<<metric); 234 } 235 236 static inline void dst_hold(struct dst_entry *dst) 237 { 238 /* 239 * If your kernel compilation stops here, please check 240 * __pad_to_align_refcnt declaration in struct dst_entry 241 */ 242 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63); 243 atomic_inc(&dst->__refcnt); 244 } 245 246 static inline void dst_use(struct dst_entry *dst, unsigned long time) 247 { 248 dst_hold(dst); 249 dst->__use++; 250 dst->lastuse = time; 251 } 252 253 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time) 254 { 255 dst->__use++; 256 dst->lastuse = time; 257 } 258 259 static inline struct dst_entry *dst_clone(struct dst_entry *dst) 260 { 261 if (dst) 262 atomic_inc(&dst->__refcnt); 263 return dst; 264 } 265 266 void dst_release(struct dst_entry *dst); 267 268 static inline void refdst_drop(unsigned long refdst) 269 { 270 if (!(refdst & SKB_DST_NOREF)) 271 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK)); 272 } 273 274 /** 275 * skb_dst_drop - drops skb dst 276 * @skb: buffer 277 * 278 * Drops dst reference count if a reference was taken. 279 */ 280 static inline void skb_dst_drop(struct sk_buff *skb) 281 { 282 if (skb->_skb_refdst) { 283 refdst_drop(skb->_skb_refdst); 284 skb->_skb_refdst = 0UL; 285 } 286 } 287 288 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb) 289 { 290 nskb->_skb_refdst = oskb->_skb_refdst; 291 if (!(nskb->_skb_refdst & SKB_DST_NOREF)) 292 dst_clone(skb_dst(nskb)); 293 } 294 295 /** 296 * skb_dst_force - makes sure skb dst is refcounted 297 * @skb: buffer 298 * 299 * If dst is not yet refcounted, let's do it 300 */ 301 static inline void skb_dst_force(struct sk_buff *skb) 302 { 303 if (skb_dst_is_noref(skb)) { 304 WARN_ON(!rcu_read_lock_held()); 305 skb->_skb_refdst &= ~SKB_DST_NOREF; 306 dst_clone(skb_dst(skb)); 307 } 308 } 309 310 311 /** 312 * __skb_tunnel_rx - prepare skb for rx reinsert 313 * @skb: buffer 314 * @dev: tunnel device 315 * @net: netns for packet i/o 316 * 317 * After decapsulation, packet is going to re-enter (netif_rx()) our stack, 318 * so make some cleanups. (no accounting done) 319 */ 320 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev, 321 struct net *net) 322 { 323 skb->dev = dev; 324 325 /* 326 * Clear hash so that we can recalulate the hash for the 327 * encapsulated packet, unless we have already determine the hash 328 * over the L4 4-tuple. 329 */ 330 skb_clear_hash_if_not_l4(skb); 331 skb_set_queue_mapping(skb, 0); 332 skb_scrub_packet(skb, !net_eq(net, dev_net(dev))); 333 } 334 335 /** 336 * skb_tunnel_rx - prepare skb for rx reinsert 337 * @skb: buffer 338 * @dev: tunnel device 339 * 340 * After decapsulation, packet is going to re-enter (netif_rx()) our stack, 341 * so make some cleanups, and perform accounting. 342 * Note: this accounting is not SMP safe. 343 */ 344 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev, 345 struct net *net) 346 { 347 /* TODO : stats should be SMP safe */ 348 dev->stats.rx_packets++; 349 dev->stats.rx_bytes += skb->len; 350 __skb_tunnel_rx(skb, dev, net); 351 } 352 353 int dst_discard_sk(struct sock *sk, struct sk_buff *skb); 354 static inline int dst_discard(struct sk_buff *skb) 355 { 356 return dst_discard_sk(skb->sk, skb); 357 } 358 void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref, 359 int initial_obsolete, unsigned short flags); 360 void dst_init(struct dst_entry *dst, struct dst_ops *ops, 361 struct net_device *dev, int initial_ref, int initial_obsolete, 362 unsigned short flags); 363 void __dst_free(struct dst_entry *dst); 364 struct dst_entry *dst_destroy(struct dst_entry *dst); 365 366 static inline void dst_free(struct dst_entry *dst) 367 { 368 if (dst->obsolete > 0) 369 return; 370 if (!atomic_read(&dst->__refcnt)) { 371 dst = dst_destroy(dst); 372 if (!dst) 373 return; 374 } 375 __dst_free(dst); 376 } 377 378 static inline void dst_rcu_free(struct rcu_head *head) 379 { 380 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head); 381 dst_free(dst); 382 } 383 384 static inline void dst_confirm(struct dst_entry *dst) 385 { 386 dst->pending_confirm = 1; 387 } 388 389 static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n, 390 struct sk_buff *skb) 391 { 392 const struct hh_cache *hh; 393 394 if (dst->pending_confirm) { 395 unsigned long now = jiffies; 396 397 dst->pending_confirm = 0; 398 /* avoid dirtying neighbour */ 399 if (n->confirmed != now) 400 n->confirmed = now; 401 } 402 403 hh = &n->hh; 404 if ((n->nud_state & NUD_CONNECTED) && hh->hh_len) 405 return neigh_hh_output(hh, skb); 406 else 407 return n->output(n, skb); 408 } 409 410 static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr) 411 { 412 struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr); 413 return IS_ERR(n) ? NULL : n; 414 } 415 416 static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst, 417 struct sk_buff *skb) 418 { 419 struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL); 420 return IS_ERR(n) ? NULL : n; 421 } 422 423 static inline void dst_link_failure(struct sk_buff *skb) 424 { 425 struct dst_entry *dst = skb_dst(skb); 426 if (dst && dst->ops && dst->ops->link_failure) 427 dst->ops->link_failure(skb); 428 } 429 430 static inline void dst_set_expires(struct dst_entry *dst, int timeout) 431 { 432 unsigned long expires = jiffies + timeout; 433 434 if (expires == 0) 435 expires = 1; 436 437 if (dst->expires == 0 || time_before(expires, dst->expires)) 438 dst->expires = expires; 439 } 440 441 /* Output packet to network from transport. */ 442 static inline int dst_output_sk(struct sock *sk, struct sk_buff *skb) 443 { 444 return skb_dst(skb)->output(sk, skb); 445 } 446 static inline int dst_output(struct sk_buff *skb) 447 { 448 return dst_output_sk(skb->sk, skb); 449 } 450 451 /* Input packet from network to transport. */ 452 static inline int dst_input(struct sk_buff *skb) 453 { 454 return skb_dst(skb)->input(skb); 455 } 456 457 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie) 458 { 459 if (dst->obsolete) 460 dst = dst->ops->check(dst, cookie); 461 return dst; 462 } 463 464 void dst_subsys_init(void); 465 466 /* Flags for xfrm_lookup flags argument. */ 467 enum { 468 XFRM_LOOKUP_ICMP = 1 << 0, 469 XFRM_LOOKUP_QUEUE = 1 << 1, 470 XFRM_LOOKUP_KEEP_DST_REF = 1 << 2, 471 }; 472 473 struct flowi; 474 #ifndef CONFIG_XFRM 475 static inline struct dst_entry *xfrm_lookup(struct net *net, 476 struct dst_entry *dst_orig, 477 const struct flowi *fl, struct sock *sk, 478 int flags) 479 { 480 return dst_orig; 481 } 482 483 static inline struct dst_entry *xfrm_lookup_route(struct net *net, 484 struct dst_entry *dst_orig, 485 const struct flowi *fl, 486 struct sock *sk, 487 int flags) 488 { 489 return dst_orig; 490 } 491 492 static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) 493 { 494 return NULL; 495 } 496 497 #else 498 struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig, 499 const struct flowi *fl, struct sock *sk, 500 int flags); 501 502 struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig, 503 const struct flowi *fl, struct sock *sk, 504 int flags); 505 506 /* skb attached with this dst needs transformation if dst->xfrm is valid */ 507 static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) 508 { 509 return dst->xfrm; 510 } 511 #endif 512 513 #endif /* _NET_DST_H */ 514