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Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __NET_FRAG_H__
3#define __NET_FRAG_H__
4
5struct netns_frags {
6 /* Keep atomic mem on separate cachelines in structs that include it */
7 atomic_t mem ____cacheline_aligned_in_smp;
8 /* sysctls */
9 int timeout;
10 int high_thresh;
11 int low_thresh;
12 int max_dist;
13};
14
15/**
16 * fragment queue flags
17 *
18 * @INET_FRAG_FIRST_IN: first fragment has arrived
19 * @INET_FRAG_LAST_IN: final fragment has arrived
20 * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
21 */
22enum {
23 INET_FRAG_FIRST_IN = BIT(0),
24 INET_FRAG_LAST_IN = BIT(1),
25 INET_FRAG_COMPLETE = BIT(2),
26};
27
28/**
29 * struct inet_frag_queue - fragment queue
30 *
31 * @lock: spinlock protecting the queue
32 * @timer: queue expiration timer
33 * @list: hash bucket list
34 * @refcnt: reference count of the queue
35 * @fragments: received fragments head
36 * @fragments_tail: received fragments tail
37 * @stamp: timestamp of the last received fragment
38 * @len: total length of the original datagram
39 * @meat: length of received fragments so far
40 * @flags: fragment queue flags
41 * @max_size: maximum received fragment size
42 * @net: namespace that this frag belongs to
43 * @list_evictor: list of queues to forcefully evict (e.g. due to low memory)
44 */
45struct inet_frag_queue {
46 spinlock_t lock;
47 struct timer_list timer;
48 struct hlist_node list;
49 refcount_t refcnt;
50 struct sk_buff *fragments;
51 struct sk_buff *fragments_tail;
52 ktime_t stamp;
53 int len;
54 int meat;
55 __u8 flags;
56 u16 max_size;
57 struct netns_frags *net;
58 struct hlist_node list_evictor;
59};
60
61#define INETFRAGS_HASHSZ 1024
62
63/* averaged:
64 * max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ /
65 * rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or
66 * struct frag_queue))
67 */
68#define INETFRAGS_MAXDEPTH 128
69
70struct inet_frag_bucket {
71 struct hlist_head chain;
72 spinlock_t chain_lock;
73};
74
75struct inet_frags {
76 struct inet_frag_bucket hash[INETFRAGS_HASHSZ];
77
78 struct work_struct frags_work;
79 unsigned int next_bucket;
80 unsigned long last_rebuild_jiffies;
81 bool rebuild;
82
83 /* The first call to hashfn is responsible to initialize
84 * rnd. This is best done with net_get_random_once.
85 *
86 * rnd_seqlock is used to let hash insertion detect
87 * when it needs to re-lookup the hash chain to use.
88 */
89 u32 rnd;
90 seqlock_t rnd_seqlock;
91 unsigned int qsize;
92
93 unsigned int (*hashfn)(const struct inet_frag_queue *);
94 bool (*match)(const struct inet_frag_queue *q,
95 const void *arg);
96 void (*constructor)(struct inet_frag_queue *q,
97 const void *arg);
98 void (*destructor)(struct inet_frag_queue *);
99 void (*frag_expire)(struct timer_list *t);
100 struct kmem_cache *frags_cachep;
101 const char *frags_cache_name;
102};
103
104int inet_frags_init(struct inet_frags *);
105void inet_frags_fini(struct inet_frags *);
106
107static inline void inet_frags_init_net(struct netns_frags *nf)
108{
109 atomic_set(&nf->mem, 0);
110}
111void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f);
112
113void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f);
114void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f);
115struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
116 struct inet_frags *f, void *key, unsigned int hash);
117
118void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
119 const char *prefix);
120
121static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
122{
123 if (refcount_dec_and_test(&q->refcnt))
124 inet_frag_destroy(q, f);
125}
126
127static inline bool inet_frag_evicting(struct inet_frag_queue *q)
128{
129 return !hlist_unhashed(&q->list_evictor);
130}
131
132/* Memory Tracking Functions. */
133
134static inline int frag_mem_limit(struct netns_frags *nf)
135{
136 return atomic_read(&nf->mem);
137}
138
139static inline void sub_frag_mem_limit(struct netns_frags *nf, int i)
140{
141 atomic_sub(i, &nf->mem);
142}
143
144static inline void add_frag_mem_limit(struct netns_frags *nf, int i)
145{
146 atomic_add(i, &nf->mem);
147}
148
149static inline int sum_frag_mem_limit(struct netns_frags *nf)
150{
151 return atomic_read(&nf->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#endif