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         /* The percpu_counter "mem" need to be cacheline aligned.
   8          *  mem.count must not share cacheline with other writers
   9          */
  10         struct percpu_counter   mem ____cacheline_aligned_in_smp;
  11
  12         /* sysctls */
  13         int                     timeout;
  14         int                     high_thresh;
  15         int                     low_thresh;
  16 };
  17
  18 struct inet_frag_queue {
  19         spinlock_t              lock;
  20         struct timer_list       timer;      /* when will this queue expire? */
  21         struct hlist_node       list;
  22         atomic_t                refcnt;
  23         struct sk_buff          *fragments; /* list of received fragments */
  24         struct sk_buff          *fragments_tail;
  25         ktime_t                 stamp;
  26         int                     len;        /* total length of orig datagram */
  27         int                     meat;
  28         __u8                    last_in;    /* first/last segment arrived? */
  29
  30 #define INET_FRAG_EVICTED       8
  31 #define INET_FRAG_COMPLETE      4
  32 #define INET_FRAG_FIRST_IN      2
  33 #define INET_FRAG_LAST_IN       1
  34
  35         u16                     max_size;
  36
  37         struct netns_frags      *net;
  38 };
  39
  40 #define INETFRAGS_HASHSZ        1024
  41
  42 /* averaged:
  43  * max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ /
  44  *             rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or
  45  *             struct frag_queue))
  46  */
  47 #define INETFRAGS_MAXDEPTH      128
  48
  49 struct inet_frag_bucket {
  50         struct hlist_head       chain;
  51         spinlock_t              chain_lock;
  52 };
  53
  54 struct inet_frags {
  55         struct inet_frag_bucket hash[INETFRAGS_HASHSZ];
  56         /* This rwlock is a global lock (seperate per IPv4, IPv6 and
  57          * netfilter). Important to keep this on a seperate cacheline.
  58          * Its primarily a rebuild protection rwlock.
  59          */
  60         rwlock_t                lock ____cacheline_aligned_in_smp;
  61         int                     secret_interval;
  62         struct timer_list       secret_timer;
  63
  64         struct work_struct      frags_work;
  65         unsigned int next_bucket;
  66
  67         /* The first call to hashfn is responsible to initialize
  68          * rnd. This is best done with net_get_random_once.
  69          */
  70         u32                     rnd;
  71         int                     qsize;
  72
  73         unsigned int            (*hashfn)(const struct inet_frag_queue *);
  74         bool                    (*match)(const struct inet_frag_queue *q,
  75                                          const void *arg);
  76         void                    (*constructor)(struct inet_frag_queue *q,
  77                                                const 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, struct inet_frags *f);
  91 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
  92                 struct inet_frags *f, void *key, unsigned int hash)
  93         __releases(&f->lock);
  94 void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
  95                                    const char *prefix);
  96
  97 static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
  98 {
  99         if (atomic_dec_and_test(&q->refcnt))
 100                 inet_frag_destroy(q, f);
 101 }
 102
 103 /* Memory Tracking Functions. */
 104
 105 /* The default percpu_counter batch size is not big enough to scale to
 106  * fragmentation mem acct sizes.
 107  * The mem size of a 64K fragment is approx:
 108  *  (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes
 109  */
 110 static unsigned int frag_percpu_counter_batch = 130000;
 111
 112 static inline int frag_mem_limit(struct netns_frags *nf)
 113 {
 114         return percpu_counter_read(&nf->mem);
 115 }
 116
 117 static inline void sub_frag_mem_limit(struct inet_frag_queue *q, int i)
 118 {
 119         __percpu_counter_add(&q->net->mem, -i, frag_percpu_counter_batch);
 120 }
 121
 122 static inline void add_frag_mem_limit(struct inet_frag_queue *q, int i)
 123 {
 124         __percpu_counter_add(&q->net->mem, i, frag_percpu_counter_batch);
 125 }
 126
 127 static inline void init_frag_mem_limit(struct netns_frags *nf)
 128 {
 129         percpu_counter_init(&nf->mem, 0);
 130 }
 131
 132 static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf)
 133 {
 134         unsigned int res;
 135
 136         local_bh_disable();
 137         res = percpu_counter_sum_positive(&nf->mem);
 138         local_bh_enable();
 139
 140         return res;
 141 }
 142
 143 /* RFC 3168 support :
 144  * We want to check ECN values of all fragments, do detect invalid combinations.
 145  * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
 146  */
 147 #define IPFRAG_ECN_NOT_ECT      0x01 /* one frag had ECN_NOT_ECT */
 148 #define IPFRAG_ECN_ECT_1        0x02 /* one frag had ECN_ECT_1 */
 149 #define IPFRAG_ECN_ECT_0        0x04 /* one frag had ECN_ECT_0 */
 150 #define IPFRAG_ECN_CE           0x08 /* one frag had ECN_CE */
 151
 152 extern const u8 ip_frag_ecn_table[16];
 153
 154 #endif