1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
#ifndef __NET_FRAG_H__
#define __NET_FRAG_H__
struct netns_frags {
/* Keep atomic mem on separate cachelines in structs that include it */
atomic_t mem ____cacheline_aligned_in_smp;
/* sysctls */
int timeout;
int high_thresh;
int low_thresh;
int max_dist;
};
/**
* fragment queue flags
*
* @INET_FRAG_FIRST_IN: first fragment has arrived
* @INET_FRAG_LAST_IN: final fragment has arrived
* @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
*/
enum {
INET_FRAG_FIRST_IN = BIT(0),
INET_FRAG_LAST_IN = BIT(1),
INET_FRAG_COMPLETE = BIT(2),
};
/**
* struct inet_frag_queue - fragment queue
*
* @lock: spinlock protecting the queue
* @timer: queue expiration timer
* @list: hash bucket list
* @refcnt: reference count of the queue
* @fragments: received fragments head
* @fragments_tail: received fragments tail
* @stamp: timestamp of the last received fragment
* @len: total length of the original datagram
* @meat: length of received fragments so far
* @flags: fragment queue flags
* @max_size: maximum received fragment size
* @net: namespace that this frag belongs to
* @list_evictor: list of queues to forcefully evict (e.g. due to low memory)
*/
struct inet_frag_queue {
spinlock_t lock;
struct timer_list timer;
struct hlist_node list;
refcount_t refcnt;
struct sk_buff *fragments;
struct sk_buff *fragments_tail;
ktime_t stamp;
int len;
int meat;
__u8 flags;
u16 max_size;
struct netns_frags *net;
struct hlist_node list_evictor;
};
#define INETFRAGS_HASHSZ 1024
/* averaged:
* max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ /
* rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or
* struct frag_queue))
*/
#define INETFRAGS_MAXDEPTH 128
struct inet_frag_bucket {
struct hlist_head chain;
spinlock_t chain_lock;
};
struct inet_frags {
struct inet_frag_bucket hash[INETFRAGS_HASHSZ];
struct work_struct frags_work;
unsigned int next_bucket;
unsigned long last_rebuild_jiffies;
bool rebuild;
/* The first call to hashfn is responsible to initialize
* rnd. This is best done with net_get_random_once.
*
* rnd_seqlock is used to let hash insertion detect
* when it needs to re-lookup the hash chain to use.
*/
u32 rnd;
seqlock_t rnd_seqlock;
unsigned int qsize;
unsigned int (*hashfn)(const struct inet_frag_queue *);
bool (*match)(const struct inet_frag_queue *q,
const void *arg);
void (*constructor)(struct inet_frag_queue *q,
const void *arg);
void (*destructor)(struct inet_frag_queue *);
void (*frag_expire)(unsigned long data);
struct kmem_cache *frags_cachep;
const char *frags_cache_name;
};
int inet_frags_init(struct inet_frags *);
void inet_frags_fini(struct inet_frags *);
static inline void inet_frags_init_net(struct netns_frags *nf)
{
atomic_set(&nf->mem, 0);
}
void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f);
void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f);
void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f);
struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
struct inet_frags *f, void *key, unsigned int hash);
void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
const char *prefix);
static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
{
if (refcount_dec_and_test(&q->refcnt))
inet_frag_destroy(q, f);
}
static inline bool inet_frag_evicting(struct inet_frag_queue *q)
{
return !hlist_unhashed(&q->list_evictor);
}
/* Memory Tracking Functions. */
static inline int frag_mem_limit(struct netns_frags *nf)
{
return atomic_read(&nf->mem);
}
static inline void sub_frag_mem_limit(struct netns_frags *nf, int i)
{
atomic_sub(i, &nf->mem);
}
static inline void add_frag_mem_limit(struct netns_frags *nf, int i)
{
atomic_add(i, &nf->mem);
}
static inline int sum_frag_mem_limit(struct netns_frags *nf)
{
return atomic_read(&nf->mem);
}
/* RFC 3168 support :
* We want to check ECN values of all fragments, do detect invalid combinations.
* In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
*/
#define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */
#define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */
#define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */
#define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */
extern const u8 ip_frag_ecn_table[16];
#endif
|
