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 * @mono_delivery_time: stamp has a mono delivery time (EDT)
  74 * @flags: fragment queue flags
  75 * @max_size: maximum received fragment size
  76 * @fqdir: pointer to struct fqdir
  77 * @rcu: rcu head for freeing deferall
  78 */
  79struct inet_frag_queue {
  80        struct rhash_head       node;
  81        union {
  82                struct frag_v4_compare_key v4;
  83                struct frag_v6_compare_key v6;
  84        } key;
  85        struct timer_list       timer;
  86        spinlock_t              lock;
  87        refcount_t              refcnt;
  88        struct rb_root          rb_fragments;
  89        struct sk_buff          *fragments_tail;
  90        struct sk_buff          *last_run_head;
  91        ktime_t                 stamp;
  92        int                     len;
  93        int                     meat;
  94        u8                      mono_delivery_time;
  95        __u8                    flags;
  96        u16                     max_size;
  97        struct fqdir            *fqdir;
  98        struct rcu_head         rcu;
  99};
 100
 101struct inet_frags {
 102        unsigned int            qsize;
 103
 104        void                    (*constructor)(struct inet_frag_queue *q,
 105                                               const void *arg);
 106        void                    (*destructor)(struct inet_frag_queue *);
 107        void                    (*frag_expire)(struct timer_list *t);
 108        struct kmem_cache       *frags_cachep;
 109        const char              *frags_cache_name;
 110        struct rhashtable_params rhash_params;
 111        refcount_t              refcnt;
 112        struct completion       completion;
 113};
 114
 115int inet_frags_init(struct inet_frags *);
 116void inet_frags_fini(struct inet_frags *);
 117
 118int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);
 119
 120static inline void fqdir_pre_exit(struct fqdir *fqdir)
 121{
 122        /* Prevent creation of new frags.
 123         * Pairs with READ_ONCE() in inet_frag_find().
 124         */
 125        WRITE_ONCE(fqdir->high_thresh, 0);
 126
 127        /* Pairs with READ_ONCE() in inet_frag_kill(), ip_expire()
 128         * and ip6frag_expire_frag_queue().
 129         */
 130        WRITE_ONCE(fqdir->dead, true);
 131}
 132void fqdir_exit(struct fqdir *fqdir);
 133
 134void inet_frag_kill(struct inet_frag_queue *q);
 135void inet_frag_destroy(struct inet_frag_queue *q);
 136struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key);
 137
 138/* Free all skbs in the queue; return the sum of their truesizes. */
 139unsigned int inet_frag_rbtree_purge(struct rb_root *root);
 140
 141static inline void inet_frag_put(struct inet_frag_queue *q)
 142{
 143        if (refcount_dec_and_test(&q->refcnt))
 144                inet_frag_destroy(q);
 145}
 146
 147/* Memory Tracking Functions. */
 148
 149static inline long frag_mem_limit(const struct fqdir *fqdir)
 150{
 151        return atomic_long_read(&fqdir->mem);
 152}
 153
 154static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
 155{
 156        atomic_long_sub(val, &fqdir->mem);
 157}
 158
 159static inline void add_frag_mem_limit(struct fqdir *fqdir, long val)
 160{
 161        atomic_long_add(val, &fqdir->mem);
 162}
 163
 164/* RFC 3168 support :
 165 * We want to check ECN values of all fragments, do detect invalid combinations.
 166 * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
 167 */
 168#define IPFRAG_ECN_NOT_ECT      0x01 /* one frag had ECN_NOT_ECT */
 169#define IPFRAG_ECN_ECT_1        0x02 /* one frag had ECN_ECT_1 */
 170#define IPFRAG_ECN_ECT_0        0x04 /* one frag had ECN_ECT_0 */
 171#define IPFRAG_ECN_CE           0x08 /* one frag had ECN_CE */
 172
 173extern const u8 ip_frag_ecn_table[16];
 174
 175/* Return values of inet_frag_queue_insert() */
 176#define IPFRAG_OK       0
 177#define IPFRAG_DUP      1
 178#define IPFRAG_OVERLAP  2
 179int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
 180                           int offset, int end);
 181void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
 182                              struct sk_buff *parent);
 183void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
 184                            void *reasm_data, bool try_coalesce);
 185struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
 186
 187#endif
 188