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