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 */
9 struct 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 */
35 enum {
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
42 struct frag_v4_compare_key {
43 __be32 saddr;
44 __be32 daddr;
45 u32 user;
46 u32 vif;
47 __be16 id;
48 u16 protocol;
49 };
50
51 struct 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 */
78 struct 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
99 struct 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
113 int inet_frags_init(struct inet_frags *);
114 void inet_frags_fini(struct inet_frags *);
115
116 int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);
117
fqdir_pre_exit(struct fqdir * fqdir)118 static inline void fqdir_pre_exit(struct fqdir *fqdir)
119 {
120 fqdir->high_thresh = 0; /* prevent creation of new frags */
121 fqdir->dead = true;
122 }
123 void fqdir_exit(struct fqdir *fqdir);
124
125 void inet_frag_kill(struct inet_frag_queue *q);
126 void inet_frag_destroy(struct inet_frag_queue *q);
127 struct 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. */
130 unsigned int inet_frag_rbtree_purge(struct rb_root *root);
131
inet_frag_put(struct inet_frag_queue * q)132 static 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
frag_mem_limit(const struct fqdir * fqdir)140 static inline long frag_mem_limit(const struct fqdir *fqdir)
141 {
142 return atomic_long_read(&fqdir->mem);
143 }
144
sub_frag_mem_limit(struct fqdir * fqdir,long val)145 static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
146 {
147 atomic_long_sub(val, &fqdir->mem);
148 }
149
add_frag_mem_limit(struct fqdir * fqdir,long val)150 static 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
164 extern 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
170 int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
171 int offset, int end);
172 void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
173 struct sk_buff *parent);
174 void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
175 void *reasm_data, bool try_coalesce);
176 struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
177
178 #endif
179