include/net/inet_frag.h

   1 #ifndef __NET_FRAG_H__
   2 #define __NET_FRAG_H__
   3
   4 #include <linux/percpu_counter.h>
   5
   6 struct netns_frags {
   7         int                     nqueues;
   8         struct list_head        lru_list;
   9         spinlock_t              lru_lock;
  10
  11         /* The percpu_counter "mem" need to be cacheline aligned.
  12          *  mem.count must not share cacheline with other writers
  13          */
  14         struct percpu_counter   mem ____cacheline_aligned_in_smp;
  15
  16         /* sysctls */
  17         int                     timeout;
  18         int                     high_thresh;
  19         int                     low_thresh;
  20 };
  21
  22 struct inet_frag_queue {
  23         spinlock_t              lock;
  24         struct timer_list       timer;      /* when will this queue expire? */
  25         struct list_head        lru_list;   /* lru list member */
  26         struct hlist_node       list;
  27         atomic_t                refcnt;
  28         struct sk_buff          *fragments; /* list of received fragments */
  29         struct sk_buff          *fragments_tail;
  30         ktime_t                 stamp;
  31         int                     len;        /* total length of orig datagram */
  32         int                     meat;
  33         __u8                    last_in;    /* first/last segment arrived? */
  34
  35 #define INET_FRAG_COMPLETE      4
  36 #define INET_FRAG_FIRST_IN      2
  37 #define INET_FRAG_LAST_IN       1
  38
  39         u16                     max_size;
  40
  41         struct netns_frags      *net;
  42 };
  43
  44 #define INETFRAGS_HASHSZ                64
  45
  46 /* averaged:
  47  * max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ /
  48  *             rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or
  49  *             struct frag_queue))
  50  */
  51 #define INETFRAGS_MAXDEPTH              128
  52
  53 struct inet_frags {
  54         struct hlist_head       hash[INETFRAGS_HASHSZ];
  55         /* This rwlock is a global lock (seperate per IPv4, IPv6 and
  56          * netfilter). Important to keep this on a seperate cacheline.
  57          */
  58         rwlock_t                lock ____cacheline_aligned_in_smp;
  59         int                     secret_interval;
  60         struct timer_list       secret_timer;
  61         u32                     rnd;
  62         int                     qsize;
  63
  64         unsigned int            (*hashfn)(struct inet_frag_queue *);
  65         bool                    (*match)(struct inet_frag_queue *q, void *arg);
  66         void                    (*constructor)(struct inet_frag_queue *q,
  67                                                 void *arg);
  68         void                    (*destructor)(struct inet_frag_queue *);
  69         void                    (*skb_free)(struct sk_buff *);
  70         void                    (*frag_expire)(unsigned long data);
  71 };
  72
  73 void inet_frags_init(struct inet_frags *);
  74 void inet_frags_fini(struct inet_frags *);
  75
  76 void inet_frags_init_net(struct netns_frags *nf);
  77 void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f);
  78
  79 void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f);
  80 void inet_frag_destroy(struct inet_frag_queue *q,
  81                                 struct inet_frags *f, int *work);
  82 int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force);
  83 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
  84                 struct inet_frags *f, void *key, unsigned int hash)
  85         __releases(&f->lock);
  86 void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
  87                                    const char *prefix);
  88
  89 static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
  90 {
  91         if (atomic_dec_and_test(&q->refcnt))
  92                 inet_frag_destroy(q, f, NULL);
  93 }
  94
  95 /* Memory Tracking Functions. */
  96
  97 /* The default percpu_counter batch size is not big enough to scale to
  98  * fragmentation mem acct sizes.
  99  * The mem size of a 64K fragment is approx:
 100  *  (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes
 101  */
 102 static unsigned int frag_percpu_counter_batch = 130000;
 103
 104 static inline int frag_mem_limit(struct netns_frags *nf)
 105 {
 106         return percpu_counter_read(&nf->mem);
 107 }
 108
 109 static inline void sub_frag_mem_limit(struct inet_frag_queue *q, int i)
 110 {
 111         __percpu_counter_add(&q->net->mem, -i, frag_percpu_counter_batch);
 112 }
 113
 114 static inline void add_frag_mem_limit(struct inet_frag_queue *q, int i)
 115 {
 116         __percpu_counter_add(&q->net->mem, i, frag_percpu_counter_batch);
 117 }
 118
 119 static inline void init_frag_mem_limit(struct netns_frags *nf)
 120 {
 121         percpu_counter_init(&nf->mem, 0);
 122 }
 123
 124 static inline int sum_frag_mem_limit(struct netns_frags *nf)
 125 {
 126         int res;
 127
 128         local_bh_disable();
 129         res = percpu_counter_sum_positive(&nf->mem);
 130         local_bh_enable();
 131
 132         return res;
 133 }
 134
 135 static inline void inet_frag_lru_move(struct inet_frag_queue *q)
 136 {
 137         spin_lock(&q->net->lru_lock);
 138         list_move_tail(&q->lru_list, &q->net->lru_list);
 139         spin_unlock(&q->net->lru_lock);
 140 }
 141
 142 static inline void inet_frag_lru_del(struct inet_frag_queue *q)
 143 {
 144         spin_lock(&q->net->lru_lock);
 145         list_del(&q->lru_list);
 146         spin_unlock(&q->net->lru_lock);
 147 }
 148
 149 static inline void inet_frag_lru_add(struct netns_frags *nf,
 150                                      struct inet_frag_queue *q)
 151 {
 152         spin_lock(&nf->lru_lock);
 153         list_add_tail(&q->lru_list, &nf->lru_list);
 154         spin_unlock(&nf->lru_lock);
 155 }
 156 #endif