aboutsummaryrefslogtreecommitdiffstats
path: root/include/net/inet_frag.h
blob: bfcbc0017950372ddd39dd540ff3f6da99f2bee6 (plain) (blame)
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
165
166
167
168
169
170
171
172
173
174
175
176
177
#ifndef __NET_FRAG_H__
#define __NET_FRAG_H__

#include <linux/percpu_counter.h>

struct netns_frags {
	int			nqueues;
	struct list_head	lru_list;
	spinlock_t		lru_lock;

	/* The percpu_counter "mem" need to be cacheline aligned.
	 *  mem.count must not share cacheline with other writers
	 */
	struct percpu_counter   mem ____cacheline_aligned_in_smp;

	/* sysctls */
	int			timeout;
	int			high_thresh;
	int			low_thresh;
};

struct inet_frag_queue {
	spinlock_t		lock;
	struct timer_list	timer;      /* when will this queue expire? */
	struct list_head	lru_list;   /* lru list member */
	struct hlist_node	list;
	atomic_t		refcnt;
	struct sk_buff		*fragments; /* list of received fragments */
	struct sk_buff		*fragments_tail;
	ktime_t			stamp;
	int			len;        /* total length of orig datagram */
	int			meat;
	__u8			last_in;    /* first/last segment arrived? */

#define INET_FRAG_COMPLETE	4
#define INET_FRAG_FIRST_IN	2
#define INET_FRAG_LAST_IN	1

	u16			max_size;

	struct netns_frags	*net;
};

#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];
	/* This rwlock is a global lock (seperate per IPv4, IPv6 and
	 * netfilter). Important to keep this on a seperate cacheline.
	 * Its primarily a rebuild protection rwlock.
	 */
	rwlock_t		lock ____cacheline_aligned_in_smp;
	int			secret_interval;
	struct timer_list	secret_timer;
	u32			rnd;
	int			qsize;

	unsigned int		(*hashfn)(struct inet_frag_queue *);
	bool			(*match)(struct inet_frag_queue *q, void *arg);
	void			(*constructor)(struct inet_frag_queue *q,
						void *arg);
	void			(*destructor)(struct inet_frag_queue *);
	void			(*skb_free)(struct sk_buff *);
	void			(*frag_expire)(unsigned long data);
};

void inet_frags_init(struct inet_frags *);
void inet_frags_fini(struct inet_frags *);

void inet_frags_init_net(struct netns_frags *nf);
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, int *work);
int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force);
struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
		struct inet_frags *f, void *key, unsigned int hash)
	__releases(&f->lock);
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 (atomic_dec_and_test(&q->refcnt))
		inet_frag_destroy(q, f, NULL);
}

/* Memory Tracking Functions. */

/* The default percpu_counter batch size is not big enough to scale to
 * fragmentation mem acct sizes.
 * The mem size of a 64K fragment is approx:
 *  (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes
 */
static unsigned int frag_percpu_counter_batch = 130000;

static inline int frag_mem_limit(struct netns_frags *nf)
{
	return percpu_counter_read(&nf->mem);
}

static inline void sub_frag_mem_limit(struct inet_frag_queue *q, int i)
{
	__percpu_counter_add(&q->net->mem, -i, frag_percpu_counter_batch);
}

static inline void add_frag_mem_limit(struct inet_frag_queue *q, int i)
{
	__percpu_counter_add(&q->net->mem, i, frag_percpu_counter_batch);
}

static inline void init_frag_mem_limit(struct netns_frags *nf)
{
	percpu_counter_init(&nf->mem, 0);
}

static inline int sum_frag_mem_limit(struct netns_frags *nf)
{
	int res;

	local_bh_disable();
	res = percpu_counter_sum_positive(&nf->mem);
	local_bh_enable();

	return res;
}

static inline void inet_frag_lru_move(struct inet_frag_queue *q)
{
	spin_lock(&q->net->lru_lock);
	if (!list_empty(&q->lru_list))
		list_move_tail(&q->lru_list, &q->net->lru_list);
	spin_unlock(&q->net->lru_lock);
}

static inline void inet_frag_lru_del(struct inet_frag_queue *q)
{
	spin_lock(&q->net->lru_lock);
	list_del_init(&q->lru_list);
	q->net->nqueues--;
	spin_unlock(&q->net->lru_lock);
}

static inline void inet_frag_lru_add(struct netns_frags *nf,
				     struct inet_frag_queue *q)
{
	spin_lock(&nf->lru_lock);
	list_add_tail(&q->lru_list, &nf->lru_list);
	q->net->nqueues++;
	spin_unlock(&nf->lru_lock);
}

/* 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