LCOV - code coverage report
Current view: top level - include/net - dst.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 0 4 0.0 %
Date: 2017-01-25 Functions: 0 1 0.0 %

          Line data    Source code
       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             :         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             : #ifdef CONFIG_XFRM
      63             :         struct xfrm_state       *xfrm;
      64             : #else
      65             :         void                    *__pad1;
      66             : #endif
      67             :         int                     (*input)(struct sk_buff*);
      68             :         int                     (*output)(struct sk_buff*);
      69             : 
      70             :         struct  dst_ops         *ops;
      71             : 
      72             :         u32                     metrics[RTAX_MAX];
      73             : 
      74             : #ifdef CONFIG_NET_CLS_ROUTE
      75             :         __u32                   tclassid;
      76             : #else
      77             :         __u32                   __pad2;
      78             : #endif
      79             : 
      80             : 
      81             :         /*
      82             :          * Align __refcnt to a 64 bytes alignment
      83             :          * (L1_CACHE_SIZE would be too much)
      84             :          */
      85             : #ifdef CONFIG_64BIT
      86             :         long                    __pad_to_align_refcnt[2];
      87             : #else
      88             :         long                    __pad_to_align_refcnt[1];
      89             : #endif
      90             :         /*
      91             :          * __refcnt wants to be on a different cache line from
      92             :          * input/output/ops or performance tanks badly
      93             :          */
      94             :         atomic_t                __refcnt;       /* client references    */
      95             :         int                     __use;
      96             :         unsigned long           lastuse;
      97             :         union {
      98             :                 struct dst_entry *next;
      99             :                 struct rtable    *rt_next;
     100             :                 struct rt6_info   *rt6_next;
     101             :                 struct dn_route  *dn_next;
     102             :         };
     103             : };
     104             : 
     105             : #ifdef __KERNEL__
     106             : 
     107             : static inline u32
     108             : dst_metric(const struct dst_entry *dst, int metric)
     109             : {
     110             :         return dst->metrics[metric-1];
     111             : }
     112             : 
     113             : static inline u32
     114             : dst_feature(const struct dst_entry *dst, u32 feature)
     115             : {
     116             :         return dst_metric(dst, RTAX_FEATURES) & feature;
     117             : }
     118             : 
     119             : static inline u32 dst_mtu(const struct dst_entry *dst)
     120             : {
     121             :         u32 mtu = dst_metric(dst, RTAX_MTU);
     122             :         /*
     123             :          * Alexey put it here, so ask him about it :)
     124             :          */
     125             :         barrier();
     126             :         return mtu;
     127             : }
     128             : 
     129             : /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
     130             : static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
     131             : {
     132             :         return msecs_to_jiffies(dst_metric(dst, metric));
     133             : }
     134             : 
     135             : static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
     136             :                                       unsigned long rtt)
     137             : {
     138             :         dst->metrics[metric-1] = jiffies_to_msecs(rtt);
     139             : }
     140             : 
     141             : static inline u32
     142             : dst_allfrag(const struct dst_entry *dst)
     143             : {
     144             :         int ret = dst_feature(dst,  RTAX_FEATURE_ALLFRAG);
     145             :         /* Yes, _exactly_. This is paranoia. */
     146             :         barrier();
     147             :         return ret;
     148             : }
     149             : 
     150             : static inline int
     151             : dst_metric_locked(struct dst_entry *dst, int metric)
     152             : {
     153             :         return dst_metric(dst, RTAX_LOCK) & (1<<metric);
     154             : }
     155             : 
     156             : static inline void dst_hold(struct dst_entry * dst)
     157             : {
     158             :         /*
     159             :          * If your kernel compilation stops here, please check
     160             :          * __pad_to_align_refcnt declaration in struct dst_entry
     161             :          */
     162             :         BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
     163             :         atomic_inc(&dst->__refcnt);
     164             : }
     165             : 
     166             : static inline void dst_use(struct dst_entry *dst, unsigned long time)
     167             : {
     168             :         dst_hold(dst);
     169             :         dst->__use++;
     170             :         dst->lastuse = time;
     171             : }
     172             : 
     173             : static inline
     174             : struct dst_entry * dst_clone(struct dst_entry * dst)
     175             : {
     176             :         if (dst)
     177             :                 atomic_inc(&dst->__refcnt);
     178             :         return dst;
     179             : }
     180             : 
     181             : extern void dst_release(struct dst_entry *dst);
     182             : static inline void skb_dst_drop(struct sk_buff *skb)
     183             : {
     184           0 :         if (skb->_skb_dst)
     185           0 :                 dst_release(skb_dst(skb));
     186           0 :         skb->_skb_dst = 0UL;
     187           0 : }
     188             : 
     189             : /* Children define the path of the packet through the
     190             :  * Linux networking.  Thus, destinations are stackable.
     191             :  */
     192             : 
     193             : static inline struct dst_entry *dst_pop(struct dst_entry *dst)
     194             : {
     195             :         struct dst_entry *child = dst_clone(dst->child);
     196             : 
     197             :         dst_release(dst);
     198             :         return child;
     199             : }
     200             : 
     201             : extern int dst_discard(struct sk_buff *skb);
     202             : extern void * dst_alloc(struct dst_ops * ops);
     203             : extern void __dst_free(struct dst_entry * dst);
     204             : extern struct dst_entry *dst_destroy(struct dst_entry * dst);
     205             : 
     206             : static inline void dst_free(struct dst_entry * dst)
     207             : {
     208             :         if (dst->obsolete > 1)
     209             :                 return;
     210             :         if (!atomic_read(&dst->__refcnt)) {
     211             :                 dst = dst_destroy(dst);
     212             :                 if (!dst)
     213             :                         return;
     214             :         }
     215             :         __dst_free(dst);
     216             : }
     217             : 
     218             : static inline void dst_rcu_free(struct rcu_head *head)
     219             : {
     220             :         struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
     221             :         dst_free(dst);
     222             : }
     223             : 
     224             : static inline void dst_confirm(struct dst_entry *dst)
     225             : {
     226             :         if (dst)
     227             :                 neigh_confirm(dst->neighbour);
     228             : }
     229             : 
     230             : static inline void dst_negative_advice(struct dst_entry **dst_p,
     231             :                                        struct sock *sk)
     232             : {
     233             :         struct dst_entry * dst = *dst_p;
     234             :         if (dst && dst->ops->negative_advice) {
     235             :                 *dst_p = dst->ops->negative_advice(dst);
     236             : 
     237             :                 if (dst != *dst_p) {
     238             :                         extern void sk_reset_txq(struct sock *sk);
     239             : 
     240             :                         sk_reset_txq(sk);
     241             :                 }
     242             :         }
     243             : }
     244             : 
     245             : static inline void dst_link_failure(struct sk_buff *skb)
     246             : {
     247             :         struct dst_entry *dst = skb_dst(skb);
     248             :         if (dst && dst->ops && dst->ops->link_failure)
     249             :                 dst->ops->link_failure(skb);
     250             : }
     251             : 
     252             : static inline void dst_set_expires(struct dst_entry *dst, int timeout)
     253             : {
     254             :         unsigned long expires = jiffies + timeout;
     255             : 
     256             :         if (expires == 0)
     257             :                 expires = 1;
     258             : 
     259             :         if (dst->expires == 0 || time_before(expires, dst->expires))
     260             :                 dst->expires = expires;
     261             : }
     262             : 
     263             : /* Output packet to network from transport.  */
     264             : static inline int dst_output(struct sk_buff *skb)
     265             : {
     266             :         return skb_dst(skb)->output(skb);
     267             : }
     268             : 
     269             : /* Input packet from network to transport.  */
     270             : static inline int dst_input(struct sk_buff *skb)
     271             : {
     272             :         return skb_dst(skb)->input(skb);
     273             : }
     274             : 
     275             : static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
     276             : {
     277             :         if (dst->obsolete)
     278             :                 dst = dst->ops->check(dst, cookie);
     279             :         return dst;
     280             : }
     281             : 
     282             : extern void             dst_init(void);
     283             : 
     284             : /* Flags for xfrm_lookup flags argument. */
     285             : enum {
     286             :         XFRM_LOOKUP_WAIT = 1 << 0,
     287             :         XFRM_LOOKUP_ICMP = 1 << 1,
     288             : };
     289             : 
     290             : struct flowi;
     291             : #ifndef CONFIG_XFRM
     292             : static inline int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
     293             :                               struct flowi *fl, struct sock *sk, int flags)
     294             : {
     295             :         return 0;
     296             : } 
     297             : static inline int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
     298             :                                 struct flowi *fl, struct sock *sk, int flags)
     299             : {
     300             :         return 0;
     301             : }
     302             : #else
     303             : extern int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
     304             :                        struct flowi *fl, struct sock *sk, int flags);
     305             : extern int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
     306             :                          struct flowi *fl, struct sock *sk, int flags);
     307             : #endif
     308             : #endif
     309             : 
     310             : #endif /* _NET_DST_H */

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