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
  57         struct work_struct      frags_work;
  58         unsigned int next_bucket;
  59         unsigned long last_rebuild_jiffies;
  60         bool rebuild;
  61
  62         /* The first call to hashfn is responsible to initialize
  63          * rnd. This is best done with net_get_random_once.
  64          *
  65          * rnd_seqlock is used to let hash insertion detect
  66          * when it needs to re-lookup the hash chain to use.
  67          */
  68         u32                     rnd;
  69         seqlock_t               rnd_seqlock;
  70         int                     qsize;
  71
  72         unsigned int            (*hashfn)(const struct inet_frag_queue *);
  73         bool                    (*match)(const struct inet_frag_queue *q,
  74                                          const void *arg);
  75         void                    (*constructor)(struct inet_frag_queue *q,
  76                                                const void *arg);
  77         void                    (*destructor)(struct inet_frag_queue *);
  78         void                    (*skb_free)(struct sk_buff *);
  79         void                    (*frag_expire)(unsigned long data);
  80 };
  81
  82 void inet_frags_init(struct inet_frags *);
  83 void inet_frags_fini(struct inet_frags *);
  84
  85 void inet_frags_init_net(struct netns_frags *nf);
  86 void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f);
  87
  88 void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f);
  89 void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f);
  90 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
  91                 struct inet_frags *f, void *key, unsigned int hash);
  92
  93 void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
  94                                    const char *prefix);
  95
  96 static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
  97 {
  98         if (atomic_dec_and_test(&q->refcnt))
  99                 inet_frag_destroy(q, f);
 100 }
 101
 102 /* Memory Tracking Functions. */
 103
 104 /* The default percpu_counter batch size is not big enough to scale to
 105  * fragmentation mem acct sizes.
 106  * The mem size of a 64K fragment is approx:
 107  *  (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes
 108  */
 109 static unsigned int frag_percpu_counter_batch = 130000;
 110
 111 static inline int frag_mem_limit(struct netns_frags *nf)
 112 {
 113         return percpu_counter_read(&nf->mem);
 114 }
 115
 116 static inline void sub_frag_mem_limit(struct inet_frag_queue *q, int i)
 117 {
 118         __percpu_counter_add(&q->net->mem, -i, frag_percpu_counter_batch);
 119 }
 120
 121 static inline void add_frag_mem_limit(struct inet_frag_queue *q, int i)
 122 {
 123         __percpu_counter_add(&q->net->mem, i, frag_percpu_counter_batch);
 124 }
 125
 126 static inline void init_frag_mem_limit(struct netns_frags *nf)
 127 {
 128         percpu_counter_init(&nf->mem, 0);
 129 }
 130
 131 static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf)
 132 {
 133         unsigned int res;
 134
 135         local_bh_disable();
 136         res = percpu_counter_sum_positive(&nf->mem);
 137         local_bh_enable();
 138
 139         return res;
 140 }
 141
 142 /* RFC 3168 support :
 143  * We want to check ECN values of all fragments, do detect invalid combinations.
 144  * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
 145  */
 146 #define IPFRAG_ECN_NOT_ECT      0x01 /* one frag had ECN_NOT_ECT */
 147 #define IPFRAG_ECN_ECT_1        0x02 /* one frag had ECN_ECT_1 */
 148 #define IPFRAG_ECN_ECT_0        0x04 /* one frag had ECN_ECT_0 */
 149 #define IPFRAG_ECN_CE           0x08 /* one frag had ECN_CE */
 150
 151 extern const u8 ip_frag_ecn_table[16];
 152
 153 #endif