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