LXR linux/include/net/inet

   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 */
   9struct 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 */
  35enum {
  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
  42struct frag_v4_compare_key {
  43        __be32          saddr;
  44        __be32          daddr;
  45        u32             user;
  46        u32             vif;
  47        __be16          id;
  48        u16             protocol;
  49};
  50
  51struct 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 */
  78struct 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
  99struct 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
 113int inet_frags_init(struct inet_frags *);
 114void inet_frags_fini(struct inet_frags *);
 115
 116int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);
 117
 118static inline void fqdir_pre_exit(struct fqdir *fqdir)
 119{
 120        fqdir->high_thresh = 0; /* prevent creation of new frags */
 121        fqdir->dead = true;
 122}
 123void fqdir_exit(struct fqdir *fqdir);
 124
 125void inet_frag_kill(struct inet_frag_queue *q);
 126void inet_frag_destroy(struct inet_frag_queue *q);
 127struct 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. */
 130unsigned int inet_frag_rbtree_purge(struct rb_root *root);
 131
 132static 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
 140static inline long frag_mem_limit(const struct fqdir *fqdir)
 141{
 142        return atomic_long_read(&fqdir->mem);
 143}
 144
 145static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
 146{
 147        atomic_long_sub(val, &fqdir->mem);
 148}
 149
 150static 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
 164extern 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
 170int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
 171                           int offset, int end);
 172void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
 173                              struct sk_buff *parent);
 174void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
 175                            void *reasm_data, bool try_coalesce);
 176struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
 177
 178#endif
 179