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/jiffies.h> 16 #include <net/neighbour.h> 17 #include <asm/processor.h> 18 19 /* 20 * 0 - no debugging messages 21 * 1 - rare events and bugs (default) 22 * 2 - trace mode. 23 */ 24 #define RT_CACHE_DEBUG 0 25 26 #define DST_GC_MIN (HZ/10) 27 #define DST_GC_INC (HZ/2) 28 #define DST_GC_MAX (120*HZ) 29 30 /* Each dst_entry has reference count and sits in some parent list(s). 31 * When it is removed from parent list, it is "freed" (dst_free). 32 * After this it enters dead state (dst->obsolete > 0) and if its refcnt 33 * is zero, it can be destroyed immediately, otherwise it is added 34 * to gc list and garbage collector periodically checks the refcnt. 35 */ 36 37 struct sk_buff; 38 39 struct dst_entry { 40 struct rcu_head rcu_head; 41 struct dst_entry *child; 42 struct net_device *dev; 43 struct dst_ops *ops; 44 unsigned long _metrics; 45 unsigned long expires; 46 struct dst_entry *path; 47 struct neighbour *neighbour; 48 struct hh_cache *hh; 49 #ifdef CONFIG_XFRM 50 struct xfrm_state *xfrm; 51 #else 52 void *__pad1; 53 #endif 54 int (*input)(struct sk_buff*); 55 int (*output)(struct sk_buff*); 56 57 short error; 58 short obsolete; 59 unsigned short header_len; /* more space at head required */ 60 unsigned short trailer_len; /* space to reserve at tail */ 61 #ifdef CONFIG_IP_ROUTE_CLASSID 62 __u32 tclassid; 63 #else 64 __u32 __pad2; 65 #endif 66 67 /* 68 * Align __refcnt to a 64 bytes alignment 69 * (L1_CACHE_SIZE would be too much) 70 */ 71 #ifdef CONFIG_64BIT 72 long __pad_to_align_refcnt[1]; 73 #endif 74 /* 75 * __refcnt wants to be on a different cache line from 76 * input/output/ops or performance tanks badly 77 */ 78 atomic_t __refcnt; /* client references */ 79 int __use; 80 unsigned long lastuse; 81 int flags; 82 #define DST_HOST 0x0001 83 #define DST_NOXFRM 0x0002 84 #define DST_NOPOLICY 0x0004 85 #define DST_NOHASH 0x0008 86 #define DST_NOCACHE 0x0010 87 union { 88 struct dst_entry *next; 89 struct rtable __rcu *rt_next; 90 struct rt6_info *rt6_next; 91 struct dn_route __rcu *dn_next; 92 }; 93 }; 94 95 #ifdef __KERNEL__ 96 97 extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old); 98 extern const u32 dst_default_metrics[RTAX_MAX]; 99 100 #define DST_METRICS_READ_ONLY 0x1UL 101 #define __DST_METRICS_PTR(Y) \ 102 ((u32 *)((Y) & ~DST_METRICS_READ_ONLY)) 103 #define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics) 104 105 static inline bool dst_metrics_read_only(const struct dst_entry *dst) 106 { 107 return dst->_metrics & DST_METRICS_READ_ONLY; 108 } 109 110 extern void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old); 111 112 static inline void dst_destroy_metrics_generic(struct dst_entry *dst) 113 { 114 unsigned long val = dst->_metrics; 115 if (!(val & DST_METRICS_READ_ONLY)) 116 __dst_destroy_metrics_generic(dst, val); 117 } 118 119 static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst) 120 { 121 unsigned long p = dst->_metrics; 122 123 if (p & DST_METRICS_READ_ONLY) 124 return dst->ops->cow_metrics(dst, p); 125 return __DST_METRICS_PTR(p); 126 } 127 128 /* This may only be invoked before the entry has reached global 129 * visibility. 130 */ 131 static inline void dst_init_metrics(struct dst_entry *dst, 132 const u32 *src_metrics, 133 bool read_only) 134 { 135 dst->_metrics = ((unsigned long) src_metrics) | 136 (read_only ? DST_METRICS_READ_ONLY : 0); 137 } 138 139 static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src) 140 { 141 u32 *dst_metrics = dst_metrics_write_ptr(dest); 142 143 if (dst_metrics) { 144 u32 *src_metrics = DST_METRICS_PTR(src); 145 146 memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32)); 147 } 148 } 149 150 static inline u32 *dst_metrics_ptr(struct dst_entry *dst) 151 { 152 return DST_METRICS_PTR(dst); 153 } 154 155 static inline u32 156 dst_metric_raw(const struct dst_entry *dst, const int metric) 157 { 158 u32 *p = DST_METRICS_PTR(dst); 159 160 return p[metric-1]; 161 } 162 163 static inline u32 164 dst_metric(const struct dst_entry *dst, const int metric) 165 { 166 WARN_ON_ONCE(metric == RTAX_HOPLIMIT || 167 metric == RTAX_ADVMSS || 168 metric == RTAX_MTU); 169 return dst_metric_raw(dst, metric); 170 } 171 172 static inline u32 173 dst_metric_advmss(const struct dst_entry *dst) 174 { 175 u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS); 176 177 if (!advmss) 178 advmss = dst->ops->default_advmss(dst); 179 180 return advmss; 181 } 182 183 static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val) 184 { 185 u32 *p = dst_metrics_write_ptr(dst); 186 187 if (p) 188 p[metric-1] = val; 189 } 190 191 static inline u32 192 dst_feature(const struct dst_entry *dst, u32 feature) 193 { 194 return dst_metric(dst, RTAX_FEATURES) & feature; 195 } 196 197 static inline u32 dst_mtu(const struct dst_entry *dst) 198 { 199 u32 mtu = dst_metric_raw(dst, RTAX_MTU); 200 201 if (!mtu) 202 mtu = dst->ops->default_mtu(dst); 203 204 return mtu; 205 } 206 207 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */ 208 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric) 209 { 210 return msecs_to_jiffies(dst_metric(dst, metric)); 211 } 212 213 static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric, 214 unsigned long rtt) 215 { 216 dst_metric_set(dst, metric, jiffies_to_msecs(rtt)); 217 } 218 219 static inline u32 220 dst_allfrag(const struct dst_entry *dst) 221 { 222 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG); 223 return ret; 224 } 225 226 static inline int 227 dst_metric_locked(const struct dst_entry *dst, int metric) 228 { 229 return dst_metric(dst, RTAX_LOCK) & (1<<metric); 230 } 231 232 static inline void dst_hold(struct dst_entry * dst) 233 { 234 /* 235 * If your kernel compilation stops here, please check 236 * __pad_to_align_refcnt declaration in struct dst_entry 237 */ 238 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63); 239 atomic_inc(&dst->__refcnt); 240 } 241 242 static inline void dst_use(struct dst_entry *dst, unsigned long time) 243 { 244 dst_hold(dst); 245 dst->__use++; 246 dst->lastuse = time; 247 } 248 249 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time) 250 { 251 dst->__use++; 252 dst->lastuse = time; 253 } 254 255 static inline 256 struct dst_entry * dst_clone(struct dst_entry * dst) 257 { 258 if (dst) 259 atomic_inc(&dst->__refcnt); 260 return dst; 261 } 262 263 extern void dst_release(struct dst_entry *dst); 264 265 static inline void refdst_drop(unsigned long refdst) 266 { 267 if (!(refdst & SKB_DST_NOREF)) 268 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK)); 269 } 270 271 /** 272 * skb_dst_drop - drops skb dst 273 * @skb: buffer 274 * 275 * Drops dst reference count if a reference was taken. 276 */ 277 static inline void skb_dst_drop(struct sk_buff *skb) 278 { 279 if (skb->_skb_refdst) { 280 refdst_drop(skb->_skb_refdst); 281 skb->_skb_refdst = 0UL; 282 } 283 } 284 285 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb) 286 { 287 nskb->_skb_refdst = oskb->_skb_refdst; 288 if (!(nskb->_skb_refdst & SKB_DST_NOREF)) 289 dst_clone(skb_dst(nskb)); 290 } 291 292 /** 293 * skb_dst_force - makes sure skb dst is refcounted 294 * @skb: buffer 295 * 296 * If dst is not yet refcounted, let's do it 297 */ 298 static inline void skb_dst_force(struct sk_buff *skb) 299 { 300 if (skb_dst_is_noref(skb)) { 301 WARN_ON(!rcu_read_lock_held()); 302 skb->_skb_refdst &= ~SKB_DST_NOREF; 303 dst_clone(skb_dst(skb)); 304 } 305 } 306 307 308 /** 309 * __skb_tunnel_rx - prepare skb for rx reinsert 310 * @skb: buffer 311 * @dev: tunnel device 312 * 313 * After decapsulation, packet is going to re-enter (netif_rx()) our stack, 314 * so make some cleanups. (no accounting done) 315 */ 316 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev) 317 { 318 skb->dev = dev; 319 skb->rxhash = 0; 320 skb_set_queue_mapping(skb, 0); 321 skb_dst_drop(skb); 322 nf_reset(skb); 323 } 324 325 /** 326 * skb_tunnel_rx - prepare skb for rx reinsert 327 * @skb: buffer 328 * @dev: tunnel device 329 * 330 * After decapsulation, packet is going to re-enter (netif_rx()) our stack, 331 * so make some cleanups, and perform accounting. 332 * Note: this accounting is not SMP safe. 333 */ 334 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev) 335 { 336 /* TODO : stats should be SMP safe */ 337 dev->stats.rx_packets++; 338 dev->stats.rx_bytes += skb->len; 339 __skb_tunnel_rx(skb, dev); 340 } 341 342 /* Children define the path of the packet through the 343 * Linux networking. Thus, destinations are stackable. 344 */ 345 346 static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb) 347 { 348 struct dst_entry *child = skb_dst(skb)->child; 349 350 skb_dst_drop(skb); 351 return child; 352 } 353 354 extern int dst_discard(struct sk_buff *skb); 355 extern void *dst_alloc(struct dst_ops * ops, int initial_ref); 356 extern void __dst_free(struct dst_entry * dst); 357 extern struct dst_entry *dst_destroy(struct dst_entry * dst); 358 359 static inline void dst_free(struct dst_entry * dst) 360 { 361 if (dst->obsolete > 1) 362 return; 363 if (!atomic_read(&dst->__refcnt)) { 364 dst = dst_destroy(dst); 365 if (!dst) 366 return; 367 } 368 __dst_free(dst); 369 } 370 371 static inline void dst_rcu_free(struct rcu_head *head) 372 { 373 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head); 374 dst_free(dst); 375 } 376 377 static inline void dst_confirm(struct dst_entry *dst) 378 { 379 if (dst) 380 neigh_confirm(dst->neighbour); 381 } 382 383 static inline void dst_link_failure(struct sk_buff *skb) 384 { 385 struct dst_entry *dst = skb_dst(skb); 386 if (dst && dst->ops && dst->ops->link_failure) 387 dst->ops->link_failure(skb); 388 } 389 390 static inline void dst_set_expires(struct dst_entry *dst, int timeout) 391 { 392 unsigned long expires = jiffies + timeout; 393 394 if (expires == 0) 395 expires = 1; 396 397 if (dst->expires == 0 || time_before(expires, dst->expires)) 398 dst->expires = expires; 399 } 400 401 /* Output packet to network from transport. */ 402 static inline int dst_output(struct sk_buff *skb) 403 { 404 return skb_dst(skb)->output(skb); 405 } 406 407 /* Input packet from network to transport. */ 408 static inline int dst_input(struct sk_buff *skb) 409 { 410 return skb_dst(skb)->input(skb); 411 } 412 413 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie) 414 { 415 if (dst->obsolete) 416 dst = dst->ops->check(dst, cookie); 417 return dst; 418 } 419 420 extern void dst_init(void); 421 422 /* Flags for xfrm_lookup flags argument. */ 423 enum { 424 XFRM_LOOKUP_ICMP = 1 << 0, 425 }; 426 427 struct flowi; 428 #ifndef CONFIG_XFRM 429 static inline struct dst_entry *xfrm_lookup(struct net *net, 430 struct dst_entry *dst_orig, 431 const struct flowi *fl, struct sock *sk, 432 int flags) 433 { 434 return dst_orig; 435 } 436 #else 437 extern struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig, 438 const struct flowi *fl, struct sock *sk, 439 int flags); 440 #endif 441 #endif 442 443 #endif /* _NET_DST_H */ 444