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-types.h>
   6 #include <linux/completion.h>
   7
   8 /* Per netns frag queues directory */
   9 struct fqdir {
  10         /* sysctls */
  11         long                    high_thresh;
  12         long                    low_thresh;
  13         int                     timeout;
  14         int                     max_dist;
  15         struct inet_frags       *f;
  16         struct net              *net;
  17         bool                    dead;
  18
  19         struct rhashtable       rhashtable ____cacheline_aligned_in_smp;
  20
  21         /* Keep atomic mem on separate cachelines in structs that include it */
  22         atomic_long_t           mem ____cacheline_aligned_in_smp;
  23         struct work_struct      destroy_work;
  24         struct llist_node       free_list;
  25 };
  26
  27 /**
  28  * fragment queue flags
  29  *
  30  * @INET_FRAG_FIRST_IN: first fragment has arrived
  31  * @INET_FRAG_LAST_IN: final fragment has arrived
  32  * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
  33  * @INET_FRAG_HASH_DEAD: inet_frag_kill() has not removed fq from rhashtable
  34  */
  35 enum {
  36         INET_FRAG_FIRST_IN      = BIT(0),
  37         INET_FRAG_LAST_IN       = BIT(1),
  38         INET_FRAG_COMPLETE      = BIT(2),
  39         INET_FRAG_HASH_DEAD     = BIT(3),
  40 };
  41
  42 struct frag_v4_compare_key {
  43         __be32          saddr;
  44         __be32          daddr;
  45         u32             user;
  46         u32             vif;
  47         __be16          id;
  48         u16             protocol;
  49 };
  50
  51 struct frag_v6_compare_key {
  52         struct in6_addr saddr;
  53         struct in6_addr daddr;
  54         u32             user;
  55         __be32          id;
  56         u32             iif;
  57 };
  58
  59 /**
  60  * struct inet_frag_queue - fragment queue
  61  *
  62  * @node: rhash node
  63  * @key: keys identifying this frag.
  64  * @timer: queue expiration timer
  65  * @lock: spinlock protecting this frag
  66  * @refcnt: reference count of the queue
  67  * @rb_fragments: received fragments rb-tree root
  68  * @fragments_tail: received fragments tail
  69  * @last_run_head: the head of the last "run". see ip_fragment.c
  70  * @stamp: timestamp of the last received fragment
  71  * @len: total length of the original datagram
  72  * @meat: length of received fragments so far
  73  * @flags: fragment queue flags
  74  * @max_size: maximum received fragment size
  75  * @fqdir: pointer to struct fqdir
  76  * @rcu: rcu head for freeing deferall
  77  */
  78 struct inet_frag_queue {
  79         struct rhash_head       node;
  80         union {
  81                 struct frag_v4_compare_key v4;
  82                 struct frag_v6_compare_key v6;
  83         } key;
  84         struct timer_list       timer;
  85         spinlock_t              lock;
  86         refcount_t              refcnt;
  87         struct rb_root          rb_fragments;
  88         struct sk_buff          *fragments_tail;
  89         struct sk_buff          *last_run_head;
  90         ktime_t                 stamp;
  91         int                     len;
  92         int                     meat;
  93         __u8                    flags;
  94         u16                     max_size;
  95         struct fqdir            *fqdir;
  96         struct rcu_head         rcu;
  97 };
  98
  99 struct inet_frags {
 100         unsigned int            qsize;
 101
 102         void                    (*constructor)(struct inet_frag_queue *q,
 103                                                const void *arg);
 104         void                    (*destructor)(struct inet_frag_queue *);
 105         void                    (*frag_expire)(struct timer_list *t);
 106         struct kmem_cache       *frags_cachep;
 107         const char              *frags_cache_name;
 108         struct rhashtable_params rhash_params;
 109         refcount_t              refcnt;
 110         struct completion       completion;
 111 };
 112
 113 int inet_frags_init(struct inet_frags *);
 114 void inet_frags_fini(struct inet_frags *);
 115
 116 int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);
 117
 118 static inline void fqdir_pre_exit(struct fqdir *fqdir)
 119 {
 120         fqdir->high_thresh = 0; /* prevent creation of new frags */
 121         fqdir->dead = true;
 122 }
 123 void fqdir_exit(struct fqdir *fqdir);
 124
 125 void inet_frag_kill(struct inet_frag_queue *q);
 126 void inet_frag_destroy(struct inet_frag_queue *q);
 127 struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key);
 128
 129 /* Free all skbs in the queue; return the sum of their truesizes. */
 130 unsigned int inet_frag_rbtree_purge(struct rb_root *root);
 131
 132 static inline void inet_frag_put(struct inet_frag_queue *q)
 133 {
 134         if (refcount_dec_and_test(&q->refcnt))
 135                 inet_frag_destroy(q);
 136 }
 137
 138 /* Memory Tracking Functions. */
 139
 140 static inline long frag_mem_limit(const struct fqdir *fqdir)
 141 {
 142         return atomic_long_read(&fqdir->mem);
 143 }
 144
 145 static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
 146 {
 147         atomic_long_sub(val, &fqdir->mem);
 148 }
 149
 150 static inline void add_frag_mem_limit(struct fqdir *fqdir, long val)
 151 {
 152         atomic_long_add(val, &fqdir->mem);
 153 }
 154
 155 /* RFC 3168 support :
 156  * We want to check ECN values of all fragments, do detect invalid combinations.
 157  * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
 158  */
 159 #define IPFRAG_ECN_NOT_ECT      0x01 /* one frag had ECN_NOT_ECT */
 160 #define IPFRAG_ECN_ECT_1        0x02 /* one frag had ECN_ECT_1 */
 161 #define IPFRAG_ECN_ECT_0        0x04 /* one frag had ECN_ECT_0 */
 162 #define IPFRAG_ECN_CE           0x08 /* one frag had ECN_CE */
 163
 164 extern const u8 ip_frag_ecn_table[16];
 165
 166 /* Return values of inet_frag_queue_insert() */
 167 #define IPFRAG_OK       0
 168 #define IPFRAG_DUP      1
 169 #define IPFRAG_OVERLAP  2
 170 int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
 171                            int offset, int end);
 172 void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
 173                               struct sk_buff *parent);
 174 void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
 175                             void *reasm_data, bool try_coalesce);
 176 struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
 177
 178 #endif