include/net/inet_frag.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __NET_FRAG_H__
   3 #define __NET_FRAG_H__
   4
   5 #include <linux/rhashtable.h>
   6
   7 struct netns_frags {
   8         struct rhashtable       rhashtable ____cacheline_aligned_in_smp;
   9
  10         /* Keep atomic mem on separate cachelines in structs that include it */
  11         atomic_t                mem ____cacheline_aligned_in_smp;
  12         /* sysctls */
  13         int                     timeout;
  14         int                     high_thresh;
  15         int                     low_thresh;
  16         int                     max_dist;
  17         struct inet_frags       *f;
  18 };
  19
  20 /**
  21  * fragment queue flags
  22  *
  23  * @INET_FRAG_FIRST_IN: first fragment has arrived
  24  * @INET_FRAG_LAST_IN: final fragment has arrived
  25  * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
  26  */
  27 enum {
  28         INET_FRAG_FIRST_IN      = BIT(0),
  29         INET_FRAG_LAST_IN       = BIT(1),
  30         INET_FRAG_COMPLETE      = BIT(2),
  31 };
  32
  33 struct frag_v4_compare_key {
  34         __be32          saddr;
  35         __be32          daddr;
  36         u32             user;
  37         u32             vif;
  38         __be16          id;
  39         u16             protocol;
  40 };
  41
  42 struct frag_v6_compare_key {
  43         struct in6_addr saddr;
  44         struct in6_addr daddr;
  45         u32             user;
  46         __be32          id;
  47         u32             iif;
  48 };
  49
  50 /**
  51  * struct inet_frag_queue - fragment queue
  52  *
  53  * @node: rhash node
  54  * @key: keys identifying this frag.
  55  * @timer: queue expiration timer
  56  * @lock: spinlock protecting this frag
  57  * @refcnt: reference count of the queue
  58  * @fragments: received fragments head
  59  * @fragments_tail: received fragments tail
  60  * @stamp: timestamp of the last received fragment
  61  * @len: total length of the original datagram
  62  * @meat: length of received fragments so far
  63  * @flags: fragment queue flags
  64  * @max_size: maximum received fragment size
  65  * @net: namespace that this frag belongs to
  66  * @rcu: rcu head for freeing deferall
  67  */
  68 struct inet_frag_queue {
  69         struct rhash_head       node;
  70         union {
  71                 struct frag_v4_compare_key v4;
  72                 struct frag_v6_compare_key v6;
  73         } key;
  74         struct timer_list       timer;
  75         spinlock_t              lock;
  76         refcount_t              refcnt;
  77         struct sk_buff          *fragments;
  78         struct sk_buff          *fragments_tail;
  79         ktime_t                 stamp;
  80         int                     len;
  81         int                     meat;
  82         __u8                    flags;
  83         u16                     max_size;
  84         struct netns_frags      *net;
  85         struct rcu_head         rcu;
  86 };
  87
  88 struct inet_frags {
  89         unsigned int            qsize;
  90
  91         void                    (*constructor)(struct inet_frag_queue *q,
  92                                                const void *arg);
  93         void                    (*destructor)(struct inet_frag_queue *);
  94         void                    (*frag_expire)(struct timer_list *t);
  95         struct kmem_cache       *frags_cachep;
  96         const char              *frags_cache_name;
  97         struct rhashtable_params rhash_params;
  98 };
  99
 100 int inet_frags_init(struct inet_frags *);
 101 void inet_frags_fini(struct inet_frags *);
 102
 103 static inline int inet_frags_init_net(struct netns_frags *nf)
 104 {
 105         atomic_set(&nf->mem, 0);
 106         return rhashtable_init(&nf->rhashtable, &nf->f->rhash_params);
 107 }
 108 void inet_frags_exit_net(struct netns_frags *nf);
 109
 110 void inet_frag_kill(struct inet_frag_queue *q);
 111 void inet_frag_destroy(struct inet_frag_queue *q);
 112 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, void *key);
 113 void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
 114                                    const char *prefix);
 115
 116 static inline void inet_frag_put(struct inet_frag_queue *q)
 117 {
 118         if (refcount_dec_and_test(&q->refcnt))
 119                 inet_frag_destroy(q);
 120 }
 121
 122 /* Memory Tracking Functions. */
 123
 124 static inline int frag_mem_limit(struct netns_frags *nf)
 125 {
 126         return atomic_read(&nf->mem);
 127 }
 128
 129 static inline void sub_frag_mem_limit(struct netns_frags *nf, int i)
 130 {
 131         atomic_sub(i, &nf->mem);
 132 }
 133
 134 static inline void add_frag_mem_limit(struct netns_frags *nf, int i)
 135 {
 136         atomic_add(i, &nf->mem);
 137 }
 138
 139 /* RFC 3168 support :
 140  * We want to check ECN values of all fragments, do detect invalid combinations.
 141  * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
 142  */
 143 #define IPFRAG_ECN_NOT_ECT      0x01 /* one frag had ECN_NOT_ECT */
 144 #define IPFRAG_ECN_ECT_1        0x02 /* one frag had ECN_ECT_1 */
 145 #define IPFRAG_ECN_ECT_0        0x04 /* one frag had ECN_ECT_0 */
 146 #define IPFRAG_ECN_CE           0x08 /* one frag had ECN_CE */
 147
 148 extern const u8 ip_frag_ecn_table[16];
 149
 150 #endif