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 unsigned int rate_tokens; 56 unsigned long rate_last; /* rate limiting for ICMP */ 57 58 struct dst_entry *path; 59 60 struct neighbour *neighbour; 61 struct hh_cache *hh; 62 struct xfrm_state *xfrm; 63 64 int (*input)(struct sk_buff*); 65 int (*output)(struct sk_buff*); 66 67 struct dst_ops *ops; 68 69 u32 metrics[RTAX_MAX]; 70 71 #ifdef CONFIG_NET_CLS_ROUTE 72 __u32 tclassid; 73 #endif 74 75 /* 76 * __refcnt wants to be on a different cache line from 77 * input/output/ops or performance tanks badly 78 */ 79 atomic_t __refcnt; /* client references */ 80 int __use; 81 unsigned long lastuse; 82 union { 83 struct dst_entry *next; 84 struct rtable *rt_next; 85 struct rt6_info *rt6_next; 86 struct dn_route *dn_next; 87 }; 88 }; 89 90 91 struct dst_ops 92 { 93 unsigned short family; 94 __be16 protocol; 95 unsigned gc_thresh; 96 97 int (*gc)(struct dst_ops *ops); 98 struct dst_entry * (*check)(struct dst_entry *, __u32 cookie); 99 void (*destroy)(struct dst_entry *); 100 void (*ifdown)(struct dst_entry *, 101 struct net_device *dev, int how); 102 struct dst_entry * (*negative_advice)(struct dst_entry *); 103 void (*link_failure)(struct sk_buff *); 104 void (*update_pmtu)(struct dst_entry *dst, u32 mtu); 105 int (*local_out)(struct sk_buff *skb); 106 int entry_size; 107 108 atomic_t entries; 109 struct kmem_cache *kmem_cachep; 110 struct net *dst_net; 111 }; 112 113 #ifdef __KERNEL__ 114 115 static inline u32 116 dst_metric(const struct dst_entry *dst, int metric) 117 { 118 return dst->metrics[metric-1]; 119 } 120 121 static inline u32 dst_mtu(const struct dst_entry *dst) 122 { 123 u32 mtu = dst_metric(dst, RTAX_MTU); 124 /* 125 * Alexey put it here, so ask him about it :) 126 */ 127 barrier(); 128 return mtu; 129 } 130 131 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */ 132 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric) 133 { 134 return msecs_to_jiffies(dst_metric(dst, metric)); 135 } 136 137 static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric, 138 unsigned long rtt) 139 { 140 dst->metrics[metric-1] = jiffies_to_msecs(rtt); 141 } 142 143 static inline u32 144 dst_allfrag(const struct dst_entry *dst) 145 { 146 int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG; 147 /* Yes, _exactly_. This is paranoia. */ 148 barrier(); 149 return ret; 150 } 151 152 static inline int 153 dst_metric_locked(struct dst_entry *dst, int metric) 154 { 155 return dst_metric(dst, RTAX_LOCK) & (1<<metric); 156 } 157 158 static inline void dst_hold(struct dst_entry * dst) 159 { 160 atomic_inc(&dst->__refcnt); 161 } 162 163 static inline void dst_use(struct dst_entry *dst, unsigned long time) 164 { 165 dst_hold(dst); 166 dst->__use++; 167 dst->lastuse = time; 168 } 169 170 static inline 171 struct dst_entry * dst_clone(struct dst_entry * dst) 172 { 173 if (dst) 174 atomic_inc(&dst->__refcnt); 175 return dst; 176 } 177 178 extern void dst_release(struct dst_entry *dst); 179 180 /* Children define the path of the packet through the 181 * Linux networking. Thus, destinations are stackable. 182 */ 183 184 static inline struct dst_entry *dst_pop(struct dst_entry *dst) 185 { 186 struct dst_entry *child = dst_clone(dst->child); 187 188 dst_release(dst); 189 return child; 190 } 191 192 extern int dst_discard(struct sk_buff *skb); 193 extern void * dst_alloc(struct dst_ops * ops); 194 extern void __dst_free(struct dst_entry * dst); 195 extern struct dst_entry *dst_destroy(struct dst_entry * dst); 196 197 static inline void dst_free(struct dst_entry * dst) 198 { 199 if (dst->obsolete > 1) 200 return; 201 if (!atomic_read(&dst->__refcnt)) { 202 dst = dst_destroy(dst); 203 if (!dst) 204 return; 205 } 206 __dst_free(dst); 207 } 208 209 static inline void dst_rcu_free(struct rcu_head *head) 210 { 211 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head); 212 dst_free(dst); 213 } 214 215 static inline void dst_confirm(struct dst_entry *dst) 216 { 217 if (dst) 218 neigh_confirm(dst->neighbour); 219 } 220 221 static inline void dst_negative_advice(struct dst_entry **dst_p) 222 { 223 struct dst_entry * dst = *dst_p; 224 if (dst && dst->ops->negative_advice) 225 *dst_p = dst->ops->negative_advice(dst); 226 } 227 228 static inline void dst_link_failure(struct sk_buff *skb) 229 { 230 struct dst_entry * dst = skb->dst; 231 if (dst && dst->ops && dst->ops->link_failure) 232 dst->ops->link_failure(skb); 233 } 234 235 static inline void dst_set_expires(struct dst_entry *dst, int timeout) 236 { 237 unsigned long expires = jiffies + timeout; 238 239 if (expires == 0) 240 expires = 1; 241 242 if (dst->expires == 0 || time_before(expires, dst->expires)) 243 dst->expires = expires; 244 } 245 246 /* Output packet to network from transport. */ 247 static inline int dst_output(struct sk_buff *skb) 248 { 249 return skb->dst->output(skb); 250 } 251 252 /* Input packet from network to transport. */ 253 static inline int dst_input(struct sk_buff *skb) 254 { 255 return skb->dst->input(skb); 256 } 257 258 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie) 259 { 260 if (dst->obsolete) 261 dst = dst->ops->check(dst, cookie); 262 return dst; 263 } 264 265 extern void dst_init(void); 266 267 /* Flags for xfrm_lookup flags argument. */ 268 enum { 269 XFRM_LOOKUP_WAIT = 1 << 0, 270 XFRM_LOOKUP_ICMP = 1 << 1, 271 }; 272 273 struct flowi; 274 #ifndef CONFIG_XFRM 275 static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, 276 struct sock *sk, int flags) 277 { 278 return 0; 279 } 280 static inline int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, 281 struct sock *sk, int flags) 282 { 283 return 0; 284 } 285 #else 286 extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, 287 struct sock *sk, int flags); 288 extern int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, 289 struct sock *sk, int flags); 290 #endif 291 #endif 292 293 #endif /* _NET_DST_H */ 294