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