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        1024
  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_frag_bucket {
  54         struct hlist_head       chain;
  55         spinlock_t              chain_lock;
  56 };
  57
  58 struct inet_frags {
  59         struct inet_frag_bucket hash[INETFRAGS_HASHSZ];
  60         /* This rwlock is a global lock (seperate per IPv4, IPv6 and
  61          * netfilter). Important to keep this on a seperate cacheline.
  62          * Its primarily a rebuild protection rwlock.
  63          */
  64         rwlock_t                lock ____cacheline_aligned_in_smp;
  65         int                     secret_interval;
  66         struct timer_list       secret_timer;
  67
  68         /* The first call to hashfn is responsible to initialize
  69          * rnd. This is best done with net_get_random_once.
  70          */
  71         u32                     rnd;
  72         int                     qsize;
  73
  74         unsigned int            (*hashfn)(struct inet_frag_queue *);
  75         bool                    (*match)(struct inet_frag_queue *q, void *arg);
  76         void                    (*constructor)(struct inet_frag_queue *q,
  77                                                 void *arg);
  78         void                    (*destructor)(struct inet_frag_queue *);
  79         void                    (*skb_free)(struct sk_buff *);
  80         void                    (*frag_expire)(unsigned long data);
  81 };
  82
  83 void inet_frags_init(struct inet_frags *);
  84 void inet_frags_fini(struct inet_frags *);
  85
  86 void inet_frags_init_net(struct netns_frags *nf);
  87 void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f);
  88
  89 void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f);
  90 void inet_frag_destroy(struct inet_frag_queue *q,
  91                                 struct inet_frags *f, int *work);
  92 int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force);
  93 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
  94                 struct inet_frags *f, void *key, unsigned int hash)
  95         __releases(&f->lock);
  96 void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
  97                                    const char *prefix);
  98
  99 static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
 100 {
 101         if (atomic_dec_and_test(&q->refcnt))
 102                 inet_frag_destroy(q, f, NULL);
 103 }
 104
 105 /* Memory Tracking Functions. */
 106
 107 /* The default percpu_counter batch size is not big enough to scale to
 108  * fragmentation mem acct sizes.
 109  * The mem size of a 64K fragment is approx:
 110  *  (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes
 111  */
 112 static unsigned int frag_percpu_counter_batch = 130000;
 113
 114 static inline int frag_mem_limit(struct netns_frags *nf)
 115 {
 116         return percpu_counter_read(&nf->mem);
 117 }
 118
 119 static inline void sub_frag_mem_limit(struct inet_frag_queue *q, int i)
 120 {
 121         __percpu_counter_add(&q->net->mem, -i, frag_percpu_counter_batch);
 122 }
 123
 124 static inline void add_frag_mem_limit(struct inet_frag_queue *q, int i)
 125 {
 126         __percpu_counter_add(&q->net->mem, i, frag_percpu_counter_batch);
 127 }
 128
 129 static inline void init_frag_mem_limit(struct netns_frags *nf)
 130 {
 131         percpu_counter_init(&nf->mem, 0);
 132 }
 133
 134 static inline int sum_frag_mem_limit(struct netns_frags *nf)
 135 {
 136         int res;
 137
 138         local_bh_disable();
 139         res = percpu_counter_sum_positive(&nf->mem);
 140         local_bh_enable();
 141
 142         return res;
 143 }
 144
 145 static inline void inet_frag_lru_move(struct inet_frag_queue *q)
 146 {
 147         spin_lock(&q->net->lru_lock);
 148         if (!list_empty(&q->lru_list))
 149                 list_move_tail(&q->lru_list, &q->net->lru_list);
 150         spin_unlock(&q->net->lru_lock);
 151 }
 152
 153 static inline void inet_frag_lru_del(struct inet_frag_queue *q)
 154 {
 155         spin_lock(&q->net->lru_lock);
 156         list_del_init(&q->lru_list);
 157         q->net->nqueues--;
 158         spin_unlock(&q->net->lru_lock);
 159 }
 160
 161 static inline void inet_frag_lru_add(struct netns_frags *nf,
 162                                      struct inet_frag_queue *q)
 163 {
 164         spin_lock(&nf->lru_lock);
 165         list_add_tail(&q->lru_list, &nf->lru_list);
 166         q->net->nqueues++;
 167         spin_unlock(&nf->lru_lock);
 168 }
 169
 170 /* RFC 3168 support :
 171  * We want to check ECN values of all fragments, do detect invalid combinations.
 172  * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
 173  */
 174 #define IPFRAG_ECN_NOT_ECT      0x01 /* one frag had ECN_NOT_ECT */
 175 #define IPFRAG_ECN_ECT_1        0x02 /* one frag had ECN_ECT_1 */
 176 #define IPFRAG_ECN_ECT_0        0x04 /* one frag had ECN_ECT_0 */
 177 #define IPFRAG_ECN_CE           0x08 /* one frag had ECN_CE */
 178
 179 extern const u8 ip_frag_ecn_table[16];
 180
 181 #endif