Line data    Source code

       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           0 : static inline void fqdir_pre_exit(struct fqdir *fqdir)
     119             : {
     120           0 :         fqdir->high_thresh = 0; /* prevent creation of new frags */
     121           0 :         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           0 : static inline void inet_frag_put(struct inet_frag_queue *q)
     133             : {
     134           0 :         if (refcount_dec_and_test(&q->refcnt))
     135           0 :                 inet_frag_destroy(q);
     136           0 : }
     137             : 
     138             : /* Memory Tracking Functions. */
     139             : 
     140           0 : static inline long frag_mem_limit(const struct fqdir *fqdir)
     141             : {
     142           0 :         return atomic_long_read(&fqdir->mem);
     143             : }
     144             : 
     145           0 : static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
     146             : {
     147           0 :         atomic_long_sub(val, &fqdir->mem);
     148           0 : }
     149             : 
     150           0 : static inline void add_frag_mem_limit(struct fqdir *fqdir, long val)
     151             : {
     152           0 :         atomic_long_add(val, &fqdir->mem);
     153           0 : }
     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