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 sk_buff *); 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_NOPEER 0x0040 58 #define DST_FAKE_RTABLE 0x0080 59 #define DST_XFRM_TUNNEL 0x0100 60 #define DST_XFRM_QUEUE 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_PTR(Y) \ 114 ((u32 *)((Y) & ~DST_METRICS_READ_ONLY)) 115 #define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics) 116 117 static inline bool dst_metrics_read_only(const struct dst_entry *dst) 118 { 119 return dst->_metrics & DST_METRICS_READ_ONLY; 120 } 121 122 void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old); 123 124 static inline void dst_destroy_metrics_generic(struct dst_entry *dst) 125 { 126 unsigned long val = dst->_metrics; 127 if (!(val & DST_METRICS_READ_ONLY)) 128 __dst_destroy_metrics_generic(dst, val); 129 } 130 131 static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst) 132 { 133 unsigned long p = dst->_metrics; 134 135 BUG_ON(!p); 136 137 if (p & DST_METRICS_READ_ONLY) 138 return dst->ops->cow_metrics(dst, p); 139 return __DST_METRICS_PTR(p); 140 } 141 142 /* This may only be invoked before the entry has reached global 143 * visibility. 144 */ 145 static inline void dst_init_metrics(struct dst_entry *dst, 146 const u32 *src_metrics, 147 bool read_only) 148 { 149 dst->_metrics = ((unsigned long) src_metrics) | 150 (read_only ? DST_METRICS_READ_ONLY : 0); 151 } 152 153 static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src) 154 { 155 u32 *dst_metrics = dst_metrics_write_ptr(dest); 156 157 if (dst_metrics) { 158 u32 *src_metrics = DST_METRICS_PTR(src); 159 160 memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32)); 161 } 162 } 163 164 static inline u32 *dst_metrics_ptr(struct dst_entry *dst) 165 { 166 return DST_METRICS_PTR(dst); 167 } 168 169 static inline u32 170 dst_metric_raw(const struct dst_entry *dst, const int metric) 171 { 172 u32 *p = DST_METRICS_PTR(dst); 173 174 return p[metric-1]; 175 } 176 177 static inline u32 178 dst_metric(const struct dst_entry *dst, const int metric) 179 { 180 WARN_ON_ONCE(metric == RTAX_HOPLIMIT || 181 metric == RTAX_ADVMSS || 182 metric == RTAX_MTU); 183 return dst_metric_raw(dst, metric); 184 } 185 186 static inline u32 187 dst_metric_advmss(const struct dst_entry *dst) 188 { 189 u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS); 190 191 if (!advmss) 192 advmss = dst->ops->default_advmss(dst); 193 194 return advmss; 195 } 196 197 static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val) 198 { 199 u32 *p = dst_metrics_write_ptr(dst); 200 201 if (p) 202 p[metric-1] = val; 203 } 204 205 static inline u32 206 dst_feature(const struct dst_entry *dst, u32 feature) 207 { 208 return dst_metric(dst, RTAX_FEATURES) & feature; 209 } 210 211 static inline u32 dst_mtu(const struct dst_entry *dst) 212 { 213 return dst->ops->mtu(dst); 214 } 215 216 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */ 217 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric) 218 { 219 return msecs_to_jiffies(dst_metric(dst, metric)); 220 } 221 222 static inline u32 223 dst_allfrag(const struct dst_entry *dst) 224 { 225 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG); 226 return ret; 227 } 228 229 static inline int 230 dst_metric_locked(const struct dst_entry *dst, int metric) 231 { 232 return dst_metric(dst, RTAX_LOCK) & (1<<metric); 233 } 234 235 static inline void dst_hold(struct dst_entry *dst) 236 { 237 /* 238 * If your kernel compilation stops here, please check 239 * __pad_to_align_refcnt declaration in struct dst_entry 240 */ 241 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63); 242 atomic_inc(&dst->__refcnt); 243 } 244 245 static inline void dst_use(struct dst_entry *dst, unsigned long time) 246 { 247 dst_hold(dst); 248 dst->__use++; 249 dst->lastuse = time; 250 } 251 252 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time) 253 { 254 dst->__use++; 255 dst->lastuse = time; 256 } 257 258 static inline struct dst_entry *dst_clone(struct dst_entry *dst) 259 { 260 if (dst) 261 atomic_inc(&dst->__refcnt); 262 return dst; 263 } 264 265 void dst_release(struct dst_entry *dst); 266 267 static inline void refdst_drop(unsigned long refdst) 268 { 269 if (!(refdst & SKB_DST_NOREF)) 270 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK)); 271 } 272 273 /** 274 * skb_dst_drop - drops skb dst 275 * @skb: buffer 276 * 277 * Drops dst reference count if a reference was taken. 278 */ 279 static inline void skb_dst_drop(struct sk_buff *skb) 280 { 281 if (skb->_skb_refdst) { 282 refdst_drop(skb->_skb_refdst); 283 skb->_skb_refdst = 0UL; 284 } 285 } 286 287 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb) 288 { 289 nskb->_skb_refdst = oskb->_skb_refdst; 290 if (!(nskb->_skb_refdst & SKB_DST_NOREF)) 291 dst_clone(skb_dst(nskb)); 292 } 293 294 /** 295 * skb_dst_force - makes sure skb dst is refcounted 296 * @skb: buffer 297 * 298 * If dst is not yet refcounted, let's do it 299 */ 300 static inline void skb_dst_force(struct sk_buff *skb) 301 { 302 if (skb_dst_is_noref(skb)) { 303 WARN_ON(!rcu_read_lock_held()); 304 skb->_skb_refdst &= ~SKB_DST_NOREF; 305 dst_clone(skb_dst(skb)); 306 } 307 } 308 309 310 /** 311 * __skb_tunnel_rx - prepare skb for rx reinsert 312 * @skb: buffer 313 * @dev: tunnel device 314 * @net: netns for packet i/o 315 * 316 * After decapsulation, packet is going to re-enter (netif_rx()) our stack, 317 * so make some cleanups. (no accounting done) 318 */ 319 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev, 320 struct net *net) 321 { 322 skb->dev = dev; 323 324 /* 325 * Clear hash so that we can recalulate the hash for the 326 * encapsulated packet, unless we have already determine the hash 327 * over the L4 4-tuple. 328 */ 329 skb_clear_hash_if_not_l4(skb); 330 skb_set_queue_mapping(skb, 0); 331 skb_scrub_packet(skb, !net_eq(net, dev_net(dev))); 332 } 333 334 /** 335 * skb_tunnel_rx - prepare skb for rx reinsert 336 * @skb: buffer 337 * @dev: tunnel device 338 * 339 * After decapsulation, packet is going to re-enter (netif_rx()) our stack, 340 * so make some cleanups, and perform accounting. 341 * Note: this accounting is not SMP safe. 342 */ 343 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev, 344 struct net *net) 345 { 346 /* TODO : stats should be SMP safe */ 347 dev->stats.rx_packets++; 348 dev->stats.rx_bytes += skb->len; 349 __skb_tunnel_rx(skb, dev, net); 350 } 351 352 /* Children define the path of the packet through the 353 * Linux networking. Thus, destinations are stackable. 354 */ 355 356 static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb) 357 { 358 struct dst_entry *child = dst_clone(skb_dst(skb)->child); 359 360 skb_dst_drop(skb); 361 return child; 362 } 363 364 int dst_discard(struct sk_buff *skb); 365 void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref, 366 int initial_obsolete, unsigned short flags); 367 void __dst_free(struct dst_entry *dst); 368 struct dst_entry *dst_destroy(struct dst_entry *dst); 369 370 static inline void dst_free(struct dst_entry *dst) 371 { 372 if (dst->obsolete > 0) 373 return; 374 if (!atomic_read(&dst->__refcnt)) { 375 dst = dst_destroy(dst); 376 if (!dst) 377 return; 378 } 379 __dst_free(dst); 380 } 381 382 static inline void dst_rcu_free(struct rcu_head *head) 383 { 384 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head); 385 dst_free(dst); 386 } 387 388 static inline void dst_confirm(struct dst_entry *dst) 389 { 390 dst->pending_confirm = 1; 391 } 392 393 static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n, 394 struct sk_buff *skb) 395 { 396 const struct hh_cache *hh; 397 398 if (dst->pending_confirm) { 399 unsigned long now = jiffies; 400 401 dst->pending_confirm = 0; 402 /* avoid dirtying neighbour */ 403 if (n->confirmed != now) 404 n->confirmed = now; 405 } 406 407 hh = &n->hh; 408 if ((n->nud_state & NUD_CONNECTED) && hh->hh_len) 409 return neigh_hh_output(hh, skb); 410 else 411 return n->output(n, skb); 412 } 413 414 static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr) 415 { 416 struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr); 417 return IS_ERR(n) ? NULL : n; 418 } 419 420 static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst, 421 struct sk_buff *skb) 422 { 423 struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL); 424 return IS_ERR(n) ? NULL : n; 425 } 426 427 static inline void dst_link_failure(struct sk_buff *skb) 428 { 429 struct dst_entry *dst = skb_dst(skb); 430 if (dst && dst->ops && dst->ops->link_failure) 431 dst->ops->link_failure(skb); 432 } 433 434 static inline void dst_set_expires(struct dst_entry *dst, int timeout) 435 { 436 unsigned long expires = jiffies + timeout; 437 438 if (expires == 0) 439 expires = 1; 440 441 if (dst->expires == 0 || time_before(expires, dst->expires)) 442 dst->expires = expires; 443 } 444 445 /* Output packet to network from transport. */ 446 static inline int dst_output(struct sk_buff *skb) 447 { 448 return skb_dst(skb)->output(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_init(void); 465 466 /* Flags for xfrm_lookup flags argument. */ 467 enum { 468 XFRM_LOOKUP_ICMP = 1 << 0, 469 }; 470 471 struct flowi; 472 #ifndef CONFIG_XFRM 473 static inline struct dst_entry *xfrm_lookup(struct net *net, 474 struct dst_entry *dst_orig, 475 const struct flowi *fl, struct sock *sk, 476 int flags) 477 { 478 return dst_orig; 479 } 480 481 static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) 482 { 483 return NULL; 484 } 485 486 #else 487 struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig, 488 const struct flowi *fl, struct sock *sk, 489 int flags); 490 491 /* skb attached with this dst needs transformation if dst->xfrm is valid */ 492 static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) 493 { 494 return dst->xfrm; 495 } 496 #endif 497 498 #endif /* _NET_DST_H */ 499