4 #include <linux/percpu_counter.h>
7 /* The percpu_counter "mem" need to be cacheline aligned.
8 * mem.count must not share cacheline with other writers
10 struct percpu_counter mem ____cacheline_aligned_in_smp;
19 * fragment queue flags
21 * @INET_FRAG_FIRST_IN: first fragment has arrived
22 * @INET_FRAG_LAST_IN: final fragment has arrived
23 * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
24 * @INET_FRAG_EVICTED: frag queue is being evicted
27 INET_FRAG_FIRST_IN = BIT(0),
28 INET_FRAG_LAST_IN = BIT(1),
29 INET_FRAG_COMPLETE = BIT(2),
30 INET_FRAG_EVICTED = BIT(3)
34 * struct inet_frag_queue - fragment queue
36 * @lock: spinlock protecting the queue
37 * @timer: queue expiration timer
38 * @list: hash bucket list
39 * @refcnt: reference count of the queue
40 * @fragments: received fragments head
41 * @fragments_tail: received fragments tail
42 * @stamp: timestamp of the last received fragment
43 * @len: total length of the original datagram
44 * @meat: length of received fragments so far
45 * @flags: fragment queue flags
46 * @max_size: maximum received fragment size
47 * @net: namespace that this frag belongs to
48 * @list_evictor: list of queues to forcefully evict (e.g. due to low memory)
50 struct inet_frag_queue {
52 struct timer_list timer;
53 struct hlist_node list;
55 struct sk_buff *fragments;
56 struct sk_buff *fragments_tail;
62 struct netns_frags *net;
63 struct hlist_node list_evictor;
66 #define INETFRAGS_HASHSZ 1024
69 * max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ /
70 * rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or
73 #define INETFRAGS_MAXDEPTH 128
75 struct inet_frag_bucket {
76 struct hlist_head chain;
77 spinlock_t chain_lock;
81 struct inet_frag_bucket hash[INETFRAGS_HASHSZ];
83 struct work_struct frags_work;
84 unsigned int next_bucket;
85 unsigned long last_rebuild_jiffies;
88 /* The first call to hashfn is responsible to initialize
89 * rnd. This is best done with net_get_random_once.
91 * rnd_seqlock is used to let hash insertion detect
92 * when it needs to re-lookup the hash chain to use.
95 seqlock_t rnd_seqlock;
98 unsigned int (*hashfn)(const struct inet_frag_queue *);
99 bool (*match)(const struct inet_frag_queue *q,
101 void (*constructor)(struct inet_frag_queue *q,
103 void (*destructor)(struct inet_frag_queue *);
104 void (*skb_free)(struct sk_buff *);
105 void (*frag_expire)(unsigned long data);
106 struct kmem_cache *frags_cachep;
107 const char *frags_cache_name;
110 int inet_frags_init(struct inet_frags *);
111 void inet_frags_fini(struct inet_frags *);
113 void inet_frags_init_net(struct netns_frags *nf);
114 void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f);
116 void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f);
117 void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f);
118 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
119 struct inet_frags *f, void *key, unsigned int hash);
121 void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
124 static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
126 if (atomic_dec_and_test(&q->refcnt))
127 inet_frag_destroy(q, f);
130 /* Memory Tracking Functions. */
132 /* The default percpu_counter batch size is not big enough to scale to
133 * fragmentation mem acct sizes.
134 * The mem size of a 64K fragment is approx:
135 * (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes
137 static unsigned int frag_percpu_counter_batch = 130000;
139 static inline int frag_mem_limit(struct netns_frags *nf)
141 return percpu_counter_read(&nf->mem);
144 static inline void sub_frag_mem_limit(struct netns_frags *nf, int i)
146 __percpu_counter_add(&nf->mem, -i, frag_percpu_counter_batch);
149 static inline void add_frag_mem_limit(struct netns_frags *nf, int i)
151 __percpu_counter_add(&nf->mem, i, frag_percpu_counter_batch);
154 static inline void init_frag_mem_limit(struct netns_frags *nf)
156 percpu_counter_init(&nf->mem, 0, GFP_KERNEL);
159 static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf)
164 res = percpu_counter_sum_positive(&nf->mem);
170 /* RFC 3168 support :
171 * We want to check ECN values of all fragments, do detect invalid combinations.
172 * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
174 #define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */
175 #define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */
176 #define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */
177 #define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */
179 extern const u8 ip_frag_ecn_table[16];