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