include/net/dst.h

   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 <linux/netdevice.h>
  12 #include <linux/rtnetlink.h>
  13 #include <linux/rcupdate.h>
  14 #include <linux/jiffies.h>
  15 #include <net/neighbour.h>
  16 #include <asm/processor.h>
  17
  18 /*
  19  * 0 - no debugging messages
  20  * 1 - rare events and bugs (default)
  21  * 2 - trace mode.
  22  */
  23 #define RT_CACHE_DEBUG          0
  24
  25 #define DST_GC_MIN      (HZ/10)
  26 #define DST_GC_INC      (HZ/2)
  27 #define DST_GC_MAX      (120*HZ)
  28
  29 /* Each dst_entry has reference count and sits in some parent list(s).
  30  * When it is removed from parent list, it is "freed" (dst_free).
  31  * After this it enters dead state (dst->obsolete > 0) and if its refcnt
  32  * is zero, it can be destroyed immediately, otherwise it is added
  33  * to gc list and garbage collector periodically checks the refcnt.
  34  */
  35
  36 struct sk_buff;
  37
  38 struct dst_entry
  39 {
  40         struct rcu_head         rcu_head;
  41         struct dst_entry        *child;
  42         struct net_device       *dev;
  43         short                   error;
  44         short                   obsolete;
  45         int                     flags;
  46 #define DST_HOST                1
  47 #define DST_NOXFRM              2
  48 #define DST_NOPOLICY            4
  49 #define DST_NOHASH              8
  50         unsigned long           expires;
  51
  52         unsigned short          header_len;     /* more space at head required */
  53         unsigned short          trailer_len;    /* space to reserve at tail */
  54
  55 <<<<<<< HEAD:include/net/dst.h
  56         u32                     metrics[RTAX_MAX];
  57         struct dst_entry        *path;
  58
  59         unsigned long           rate_last;      /* rate limiting for ICMP */
  60 =======
  61 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:include/net/dst.h
  62         unsigned int            rate_tokens;
  63 <<<<<<< HEAD:include/net/dst.h
  64 =======
  65         unsigned long           rate_last;      /* rate limiting for ICMP */
  66 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:include/net/dst.h
  67
  68 <<<<<<< HEAD:include/net/dst.h
  69 #ifdef CONFIG_NET_CLS_ROUTE
  70         __u32                   tclassid;
  71 #endif
  72 =======
  73         struct dst_entry        *path;
  74 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:include/net/dst.h
  75
  76         struct neighbour        *neighbour;
  77         struct hh_cache         *hh;
  78         struct xfrm_state       *xfrm;
  79
  80         int                     (*input)(struct sk_buff*);
  81         int                     (*output)(struct sk_buff*);
  82
  83         struct  dst_ops         *ops;
  84 <<<<<<< HEAD:include/net/dst.h
  85
  86         unsigned long           lastuse;
  87 =======
  88
  89         u32                     metrics[RTAX_MAX];
  90
  91 #ifdef CONFIG_NET_CLS_ROUTE
  92         __u32                   tclassid;
  93 #endif
  94
  95         /*
  96          * __refcnt wants to be on a different cache line from
  97          * input/output/ops or performance tanks badly
  98          */
  99 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:include/net/dst.h
 100         atomic_t                __refcnt;       /* client references    */
 101         int                     __use;
 102 <<<<<<< HEAD:include/net/dst.h
 103 =======
 104         unsigned long           lastuse;
 105 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:include/net/dst.h
 106         union {
 107                 struct dst_entry *next;
 108                 struct rtable    *rt_next;
 109                 struct rt6_info   *rt6_next;
 110                 struct dn_route  *dn_next;
 111         };
 112 };
 113
 114
 115 struct dst_ops
 116 {
 117         unsigned short          family;
 118         __be16                  protocol;
 119         unsigned                gc_thresh;
 120
 121         int                     (*gc)(struct dst_ops *ops);
 122         struct dst_entry *      (*check)(struct dst_entry *, __u32 cookie);
 123         void                    (*destroy)(struct dst_entry *);
 124         void                    (*ifdown)(struct dst_entry *,
 125                                           struct net_device *dev, int how);
 126         struct dst_entry *      (*negative_advice)(struct dst_entry *);
 127         void                    (*link_failure)(struct sk_buff *);
 128         void                    (*update_pmtu)(struct dst_entry *dst, u32 mtu);
 129         int                     (*local_out)(struct sk_buff *skb);
 130         int                     entry_size;
 131
 132         atomic_t                entries;
 133         struct kmem_cache               *kmem_cachep;
 134         struct net              *dst_net;
 135 };
 136
 137 #ifdef __KERNEL__
 138
 139 static inline u32
 140 dst_metric(const struct dst_entry *dst, int metric)
 141 {
 142         return dst->metrics[metric-1];
 143 }
 144
 145 static inline u32 dst_mtu(const struct dst_entry *dst)
 146 {
 147         u32 mtu = dst_metric(dst, RTAX_MTU);
 148         /*
 149          * Alexey put it here, so ask him about it :)
 150          */
 151         barrier();
 152         return mtu;
 153 }
 154
 155 static inline u32
 156 dst_allfrag(const struct dst_entry *dst)
 157 {
 158         int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
 159         /* Yes, _exactly_. This is paranoia. */
 160         barrier();
 161         return ret;
 162 }
 163
 164 static inline int
 165 dst_metric_locked(struct dst_entry *dst, int metric)
 166 {
 167         return dst_metric(dst, RTAX_LOCK) & (1<<metric);
 168 }
 169
 170 static inline void dst_hold(struct dst_entry * dst)
 171 {
 172         atomic_inc(&dst->__refcnt);
 173 }
 174
 175 static inline void dst_use(struct dst_entry *dst, unsigned long time)
 176 {
 177         dst_hold(dst);
 178         dst->__use++;
 179         dst->lastuse = time;
 180 }
 181
 182 static inline
 183 struct dst_entry * dst_clone(struct dst_entry * dst)
 184 {
 185         if (dst)
 186                 atomic_inc(&dst->__refcnt);
 187         return dst;
 188 }
 189
 190 static inline
 191 void dst_release(struct dst_entry * dst)
 192 {
 193         if (dst) {
 194                 WARN_ON(atomic_read(&dst->__refcnt) < 1);
 195                 smp_mb__before_atomic_dec();
 196                 atomic_dec(&dst->__refcnt);
 197         }
 198 }
 199
 200 /* Children define the path of the packet through the
 201  * Linux networking.  Thus, destinations are stackable.
 202  */
 203
 204 static inline struct dst_entry *dst_pop(struct dst_entry *dst)
 205 {
 206         struct dst_entry *child = dst_clone(dst->child);
 207
 208         dst_release(dst);
 209         return child;
 210 }
 211
 212 extern int dst_discard(struct sk_buff *skb);
 213 extern void * dst_alloc(struct dst_ops * ops);
 214 extern void __dst_free(struct dst_entry * dst);
 215 extern struct dst_entry *dst_destroy(struct dst_entry * dst);
 216
 217 static inline void dst_free(struct dst_entry * dst)
 218 {
 219         if (dst->obsolete > 1)
 220                 return;
 221         if (!atomic_read(&dst->__refcnt)) {
 222                 dst = dst_destroy(dst);
 223                 if (!dst)
 224                         return;
 225         }
 226         __dst_free(dst);
 227 }
 228
 229 static inline void dst_rcu_free(struct rcu_head *head)
 230 {
 231         struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
 232         dst_free(dst);
 233 }
 234
 235 static inline void dst_confirm(struct dst_entry *dst)
 236 {
 237         if (dst)
 238                 neigh_confirm(dst->neighbour);
 239 }
 240
 241 static inline void dst_negative_advice(struct dst_entry **dst_p)
 242 {
 243         struct dst_entry * dst = *dst_p;
 244         if (dst && dst->ops->negative_advice)
 245                 *dst_p = dst->ops->negative_advice(dst);
 246 }
 247
 248 static inline void dst_link_failure(struct sk_buff *skb)
 249 {
 250         struct dst_entry * dst = skb->dst;
 251         if (dst && dst->ops && dst->ops->link_failure)
 252                 dst->ops->link_failure(skb);
 253 }
 254
 255 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
 256 {
 257         unsigned long expires = jiffies + timeout;
 258
 259         if (expires == 0)
 260                 expires = 1;
 261
 262         if (dst->expires == 0 || time_before(expires, dst->expires))
 263                 dst->expires = expires;
 264 }
 265
 266 /* Output packet to network from transport.  */
 267 static inline int dst_output(struct sk_buff *skb)
 268 {
 269         return skb->dst->output(skb);
 270 }
 271
 272 /* Input packet from network to transport.  */
 273 static inline int dst_input(struct sk_buff *skb)
 274 {
 275         int err;
 276
 277         for (;;) {
 278                 err = skb->dst->input(skb);
 279
 280                 if (likely(err == 0))
 281                         return err;
 282                 /* Oh, Jamal... Seems, I will not forgive you this mess. :-) */
 283                 if (unlikely(err != NET_XMIT_BYPASS))
 284                         return err;
 285         }
 286 }
 287
 288 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
 289 {
 290         if (dst->obsolete)
 291                 dst = dst->ops->check(dst, cookie);
 292         return dst;
 293 }
 294
 295 extern void             dst_init(void);
 296
 297 /* Flags for xfrm_lookup flags argument. */
 298 enum {
 299         XFRM_LOOKUP_WAIT = 1 << 0,
 300         XFRM_LOOKUP_ICMP = 1 << 1,
 301 };
 302
 303 struct flowi;
 304 #ifndef CONFIG_XFRM
 305 static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
 306                        struct sock *sk, int flags)
 307 {
 308         return 0;
 309 }
 310 static inline int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
 311                                 struct sock *sk, int flags)
 312 {
 313         return 0;
 314 }
 315 #else
 316 extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
 317                        struct sock *sk, int flags);
 318 extern int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
 319                          struct sock *sk, int flags);
 320 #endif
 321 #endif
 322
 323 #endif /* _NET_DST_H */