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         /* sysctls */
   9         long                    high_thresh;
  10         long                    low_thresh;
  11         int                     timeout;
  12         int                     max_dist;
  13         struct inet_frags       *f;
  14
  15         struct rhashtable       rhashtable ____cacheline_aligned_in_smp;
  16
  17         /* Keep atomic mem on separate cachelines in structs that include it */
  18         atomic_long_t           mem ____cacheline_aligned_in_smp;
  19 };
  20
  21 /**
  22  * fragment queue flags
  23  *
  24  * @INET_FRAG_FIRST_IN: first fragment has arrived
  25  * @INET_FRAG_LAST_IN: final fragment has arrived
  26  * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
  27  */
  28 enum {
  29         INET_FRAG_FIRST_IN      = BIT(0),
  30         INET_FRAG_LAST_IN       = BIT(1),
  31         INET_FRAG_COMPLETE      = BIT(2),
  32 };
  33
  34 struct frag_v4_compare_key {
  35         __be32          saddr;
  36         __be32          daddr;
  37         u32             user;
  38         u32             vif;
  39         __be16          id;
  40         u16             protocol;
  41 };
  42
  43 struct frag_v6_compare_key {
  44         struct in6_addr saddr;
  45         struct in6_addr daddr;
  46         u32             user;
  47         __be32          id;
  48         u32             iif;
  49 };
  50
  51 /**
  52  * struct inet_frag_queue - fragment queue
  53  *
  54  * @node: rhash node
  55  * @key: keys identifying this frag.
  56  * @timer: queue expiration timer
  57  * @lock: spinlock protecting this frag
  58  * @refcnt: reference count of the queue
  59  * @fragments: received fragments head
  60  * @rb_fragments: received fragments rb-tree root
  61  * @fragments_tail: received fragments tail
  62  * @last_run_head: the head of the last "run". see ip_fragment.c
  63  * @stamp: timestamp of the last received fragment
  64  * @len: total length of the original datagram
  65  * @meat: length of received fragments so far
  66  * @flags: fragment queue flags
  67  * @max_size: maximum received fragment size
  68  * @net: namespace that this frag belongs to
  69  * @rcu: rcu head for freeing deferall
  70  */
  71 struct inet_frag_queue {
  72         struct rhash_head       node;
  73         union {
  74                 struct frag_v4_compare_key v4;
  75                 struct frag_v6_compare_key v6;
  76         } key;
  77         struct timer_list       timer;
  78         spinlock_t              lock;
  79         refcount_t              refcnt;
  80         struct sk_buff          *fragments;  /* used in 6lopwpan IPv6. */
  81         struct rb_root          rb_fragments; /* Used in IPv4/IPv6. */
  82         struct sk_buff          *fragments_tail;
  83         struct sk_buff          *last_run_head;
  84         ktime_t                 stamp;
  85         int                     len;
  86         int                     meat;
  87         __u8                    flags;
  88         u16                     max_size;
  89         struct netns_frags      *net;
  90         struct rcu_head         rcu;
  91 };
  92
  93 struct inet_frags {
  94         unsigned int            qsize;
  95
  96         void                    (*constructor)(struct inet_frag_queue *q,
  97                                                const void *arg);
  98         void                    (*destructor)(struct inet_frag_queue *);
  99         void                    (*frag_expire)(struct timer_list *t);
 100         struct kmem_cache       *frags_cachep;
 101         const char              *frags_cache_name;
 102         struct rhashtable_params rhash_params;
 103 };
 104
 105 int inet_frags_init(struct inet_frags *);
 106 void inet_frags_fini(struct inet_frags *);
 107
 108 static inline int inet_frags_init_net(struct netns_frags *nf)
 109 {
 110         atomic_long_set(&nf->mem, 0);
 111         return rhashtable_init(&nf->rhashtable, &nf->f->rhash_params);
 112 }
 113 void inet_frags_exit_net(struct netns_frags *nf);
 114
 115 void inet_frag_kill(struct inet_frag_queue *q);
 116 void inet_frag_destroy(struct inet_frag_queue *q);
 117 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, void *key);
 118
 119 /* Free all skbs in the queue; return the sum of their truesizes. */
 120 unsigned int inet_frag_rbtree_purge(struct rb_root *root);
 121
 122 static inline void inet_frag_put(struct inet_frag_queue *q)
 123 {
 124         if (refcount_dec_and_test(&q->refcnt))
 125                 inet_frag_destroy(q);
 126 }
 127
 128 /* Memory Tracking Functions. */
 129
 130 static inline long frag_mem_limit(const struct netns_frags *nf)
 131 {
 132         return atomic_long_read(&nf->mem);
 133 }
 134
 135 static inline void sub_frag_mem_limit(struct netns_frags *nf, long val)
 136 {
 137         atomic_long_sub(val, &nf->mem);
 138 }
 139
 140 static inline void add_frag_mem_limit(struct netns_frags *nf, long val)
 141 {
 142         atomic_long_add(val, &nf->mem);
 143 }
 144
 145 /* RFC 3168 support :
 146  * We want to check ECN values of all fragments, do detect invalid combinations.
 147  * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
 148  */
 149 #define IPFRAG_ECN_NOT_ECT      0x01 /* one frag had ECN_NOT_ECT */
 150 #define IPFRAG_ECN_ECT_1        0x02 /* one frag had ECN_ECT_1 */
 151 #define IPFRAG_ECN_ECT_0        0x04 /* one frag had ECN_ECT_0 */
 152 #define IPFRAG_ECN_CE           0x08 /* one frag had ECN_CE */
 153
 154 extern const u8 ip_frag_ecn_table[16];
 155
 156 /* Return values of inet_frag_queue_insert() */
 157 #define IPFRAG_OK       0
 158 #define IPFRAG_DUP      1
 159 #define IPFRAG_OVERLAP  2
 160 int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
 161                            int offset, int end);
 162 void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
 163                               struct sk_buff *parent);
 164 void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
 165                             void *reasm_data);
 166 struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
 167
 168 #endif