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 #include <linux/in6.h>
8 #include <linux/rbtree_types.h>
9 #include <linux/refcount.h>
10 #include <net/dropreason-core.h>
11
12 /* Per netns frag queues directory */
13 struct fqdir {
14 /* sysctls */
15 long high_thresh;
16 long low_thresh;
17 int timeout;
18 int max_dist;
19 struct inet_frags *f;
20 struct net *net;
21 bool dead;
22
23 struct rhashtable rhashtable ____cacheline_aligned_in_smp;
24
25 /* Keep atomic mem on separate cachelines in structs that include it */
26 atomic_long_t mem ____cacheline_aligned_in_smp;
27 struct work_struct destroy_work;
28 struct llist_node free_list;
29 };
30
31 /**
32 * enum: fragment queue flags
33 *
34 * @INET_FRAG_FIRST_IN: first fragment has arrived
35 * @INET_FRAG_LAST_IN: final fragment has arrived
36 * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
37 * @INET_FRAG_HASH_DEAD: inet_frag_kill() has not removed fq from rhashtable
38 * @INET_FRAG_DROP: if skbs must be dropped (instead of being consumed)
39 */
40 enum {
41 INET_FRAG_FIRST_IN = BIT(0),
42 INET_FRAG_LAST_IN = BIT(1),
43 INET_FRAG_COMPLETE = BIT(2),
44 INET_FRAG_HASH_DEAD = BIT(3),
45 INET_FRAG_DROP = BIT(4),
46 };
47
48 struct frag_v4_compare_key {
49 __be32 saddr;
50 __be32 daddr;
51 u32 user;
52 u32 vif;
53 __be16 id;
54 u16 protocol;
55 };
56
57 struct frag_v6_compare_key {
58 struct in6_addr saddr;
59 struct in6_addr daddr;
60 u32 user;
61 __be32 id;
62 u32 iif;
63 };
64
65 /**
66 * struct inet_frag_queue - fragment queue
67 *
68 * @node: rhash node
69 * @key: keys identifying this frag.
70 * @timer: queue expiration timer
71 * @lock: spinlock protecting this frag
72 * @refcnt: reference count of the queue
73 * @rb_fragments: received fragments rb-tree root
74 * @fragments_tail: received fragments tail
75 * @last_run_head: the head of the last "run". see ip_fragment.c
76 * @stamp: timestamp of the last received fragment
77 * @len: total length of the original datagram
78 * @meat: length of received fragments so far
79 * @tstamp_type: stamp has a mono delivery time (EDT)
80 * @flags: fragment queue flags
81 * @max_size: maximum received fragment size
82 * @fqdir: pointer to struct fqdir
83 * @rcu: rcu head for freeing deferall
84 */
85 struct inet_frag_queue {
86 struct rhash_head node;
87 union {
88 struct frag_v4_compare_key v4;
89 struct frag_v6_compare_key v6;
90 } key;
91 struct timer_list timer;
92 spinlock_t lock;
93 refcount_t refcnt;
94 struct rb_root rb_fragments;
95 struct sk_buff *fragments_tail;
96 struct sk_buff *last_run_head;
97 ktime_t stamp;
98 int len;
99 int meat;
100 u8 tstamp_type;
101 __u8 flags;
102 u16 max_size;
103 struct fqdir *fqdir;
104 struct rcu_head rcu;
105 };
106
107 struct inet_frags {
108 unsigned int qsize;
109
110 void (*constructor)(struct inet_frag_queue *q,
111 const void *arg);
112 void (*destructor)(struct inet_frag_queue *);
113 void (*frag_expire)(struct timer_list *t);
114 struct kmem_cache *frags_cachep;
115 const char *frags_cache_name;
116 struct rhashtable_params rhash_params;
117 refcount_t refcnt;
118 struct completion completion;
119 };
120
121 int inet_frags_init(struct inet_frags *);
122 void inet_frags_fini(struct inet_frags *);
123
124 int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);
125
126 static inline void fqdir_pre_exit(struct fqdir *fqdir)
127 {
128 /* Prevent creation of new frags.
129 * Pairs with READ_ONCE() in inet_frag_find().
130 */
131 WRITE_ONCE(fqdir->high_thresh, 0);
132
133 /* Pairs with READ_ONCE() in inet_frag_kill(), ip_expire()
134 * and ip6frag_expire_frag_queue().
135 */
136 WRITE_ONCE(fqdir->dead, true);
137 }
138 void fqdir_exit(struct fqdir *fqdir);
139
140 void inet_frag_kill(struct inet_frag_queue *q);
141 void inet_frag_destroy(struct inet_frag_queue *q);
142 struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key);
143
144 /* Free all skbs in the queue; return the sum of their truesizes. */
145 unsigned int inet_frag_rbtree_purge(struct rb_root *root,
146 enum skb_drop_reason reason);
147
148 static inline void inet_frag_put(struct inet_frag_queue *q)
149 {
150 if (refcount_dec_and_test(&q->refcnt))
151 inet_frag_destroy(q);
152 }
153
154 /* Memory Tracking Functions. */
155
156 static inline long frag_mem_limit(const struct fqdir *fqdir)
157 {
158 return atomic_long_read(&fqdir->mem);
159 }
160
161 static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
162 {
163 atomic_long_sub(val, &fqdir->mem);
164 }
165
166 static inline void add_frag_mem_limit(struct fqdir *fqdir, long val)
167 {
168 atomic_long_add(val, &fqdir->mem);
169 }
170
171 /* RFC 3168 support :
172 * We want to check ECN values of all fragments, do detect invalid combinations.
173 * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
174 */
175 #define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */
176 #define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */
177 #define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */
178 #define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */
179
180 extern const u8 ip_frag_ecn_table[16];
181
182 /* Return values of inet_frag_queue_insert() */
183 #define IPFRAG_OK 0
184 #define IPFRAG_DUP 1
185 #define IPFRAG_OVERLAP 2
186 int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
187 int offset, int end);
188 void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
189 struct sk_buff *parent);
190 void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
191 void *reasm_data, bool try_coalesce);
192 struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
193
194 #endif
195
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