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1#ifndef __NET_FRAG_H__
2#define __NET_FRAG_H__
3
4#include <linux/percpu_counter.h>
5
6struct netns_frags {
7 /* The percpu_counter "mem" need to be cacheline aligned.
8 * mem.count must not share cacheline with other writers
9 */
10 struct percpu_counter mem ____cacheline_aligned_in_smp;
11
12 /* sysctls */
13 int timeout;
14 int high_thresh;
15 int low_thresh;
16 int max_dist;
17};
18
19/**
20 * fragment queue flags
21 *
22 * @INET_FRAG_FIRST_IN: first fragment has arrived
23 * @INET_FRAG_LAST_IN: final fragment has arrived
24 * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
25 */
26enum {
27 INET_FRAG_FIRST_IN = BIT(0),
28 INET_FRAG_LAST_IN = BIT(1),
29 INET_FRAG_COMPLETE = BIT(2),
30};
31
32/**
33 * struct inet_frag_queue - fragment queue
34 *
35 * @lock: spinlock protecting the queue
36 * @timer: queue expiration timer
37 * @list: hash bucket list
38 * @refcnt: reference count of the queue
39 * @fragments: received fragments head
40 * @fragments_tail: received fragments tail
41 * @stamp: timestamp of the last received fragment
42 * @len: total length of the original datagram
43 * @meat: length of received fragments so far
44 * @flags: fragment queue flags
45 * @max_size: maximum received fragment size
46 * @net: namespace that this frag belongs to
47 * @list_evictor: list of queues to forcefully evict (e.g. due to low memory)
48 */
49struct inet_frag_queue {
50 spinlock_t lock;
51 struct timer_list timer;
52 struct hlist_node list;
53 atomic_t refcnt;
54 struct sk_buff *fragments;
55 struct sk_buff *fragments_tail;
56 ktime_t stamp;
57 int len;
58 int meat;
59 __u8 flags;
60 u16 max_size;
61 struct netns_frags *net;
62 struct hlist_node list_evictor;
63};
64
65#define INETFRAGS_HASHSZ 1024
66
67/* averaged:
68 * max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ /
69 * rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or
70 * struct frag_queue))
71 */
72#define INETFRAGS_MAXDEPTH 128
73
74struct inet_frag_bucket {
75 struct hlist_head chain;
76 spinlock_t chain_lock;
77};
78
79struct inet_frags {
80 struct inet_frag_bucket hash[INETFRAGS_HASHSZ];
81
82 struct work_struct frags_work;
83 unsigned int next_bucket;
84 unsigned long last_rebuild_jiffies;
85 bool rebuild;
86
87 /* The first call to hashfn is responsible to initialize
88 * rnd. This is best done with net_get_random_once.
89 *
90 * rnd_seqlock is used to let hash insertion detect
91 * when it needs to re-lookup the hash chain to use.
92 */
93 u32 rnd;
94 seqlock_t rnd_seqlock;
95 int qsize;
96
97 unsigned int (*hashfn)(const struct inet_frag_queue *);
98 bool (*match)(const struct inet_frag_queue *q,
99 const void *arg);
100 void (*constructor)(struct inet_frag_queue *q,
101 const void *arg);
102 void (*destructor)(struct inet_frag_queue *);
103 void (*frag_expire)(unsigned long data);
104 struct kmem_cache *frags_cachep;
105 const char *frags_cache_name;
106};
107
108int inet_frags_init(struct inet_frags *);
109void inet_frags_fini(struct inet_frags *);
110
111static inline int inet_frags_init_net(struct netns_frags *nf)
112{
113 return percpu_counter_init(&nf->mem, 0, GFP_KERNEL);
114}
115static inline void inet_frags_uninit_net(struct netns_frags *nf)
116{
117 percpu_counter_destroy(&nf->mem);
118}
119
120void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f);
121
122void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f);
123void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f);
124struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
125 struct inet_frags *f, void *key, unsigned int hash);
126
127void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
128 const char *prefix);
129
130static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
131{
132 if (atomic_dec_and_test(&q->refcnt))
133 inet_frag_destroy(q, f);
134}
135
136static inline bool inet_frag_evicting(struct inet_frag_queue *q)
137{
138 return !hlist_unhashed(&q->list_evictor);
139}
140
141/* Memory Tracking Functions. */
142
143/* The default percpu_counter batch size is not big enough to scale to
144 * fragmentation mem acct sizes.
145 * The mem size of a 64K fragment is approx:
146 * (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes
147 */
148static unsigned int frag_percpu_counter_batch = 130000;
149
150static inline int frag_mem_limit(struct netns_frags *nf)
151{
152 return percpu_counter_read(&nf->mem);
153}
154
155static inline void sub_frag_mem_limit(struct netns_frags *nf, int i)
156{
157 __percpu_counter_add(&nf->mem, -i, frag_percpu_counter_batch);
158}
159
160static inline void add_frag_mem_limit(struct netns_frags *nf, int i)
161{
162 __percpu_counter_add(&nf->mem, i, frag_percpu_counter_batch);
163}
164
165static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf)
166{
167 unsigned int res;
168
169 local_bh_disable();
170 res = percpu_counter_sum_positive(&nf->mem);
171 local_bh_enable();
172
173 return res;
174}
175
176/* RFC 3168 support :
177 * We want to check ECN values of all fragments, do detect invalid combinations.
178 * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
179 */
180#define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */
181#define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */
182#define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */
183#define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */
184
185extern const u8 ip_frag_ecn_table[16];
186
187#endif
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 */
9struct 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 */
35enum {
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
42struct frag_v4_compare_key {
43 __be32 saddr;
44 __be32 daddr;
45 u32 user;
46 u32 vif;
47 __be16 id;
48 u16 protocol;
49};
50
51struct 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 */
78struct 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
99struct 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
113int inet_frags_init(struct inet_frags *);
114void inet_frags_fini(struct inet_frags *);
115
116int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);
117
118static inline void fqdir_pre_exit(struct fqdir *fqdir)
119{
120 fqdir->high_thresh = 0; /* prevent creation of new frags */
121 fqdir->dead = true;
122}
123void fqdir_exit(struct fqdir *fqdir);
124
125void inet_frag_kill(struct inet_frag_queue *q);
126void inet_frag_destroy(struct inet_frag_queue *q);
127struct 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. */
130unsigned int inet_frag_rbtree_purge(struct rb_root *root);
131
132static inline void inet_frag_put(struct inet_frag_queue *q)
133{
134 if (refcount_dec_and_test(&q->refcnt))
135 inet_frag_destroy(q);
136}
137
138/* Memory Tracking Functions. */
139
140static inline long frag_mem_limit(const struct fqdir *fqdir)
141{
142 return atomic_long_read(&fqdir->mem);
143}
144
145static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
146{
147 atomic_long_sub(val, &fqdir->mem);
148}
149
150static inline void add_frag_mem_limit(struct fqdir *fqdir, long val)
151{
152 atomic_long_add(val, &fqdir->mem);
153}
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
164extern 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
170int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
171 int offset, int end);
172void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
173 struct sk_buff *parent);
174void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
175 void *reasm_data, bool try_coalesce);
176struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
177
178#endif