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};
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 */
34enum {
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
41struct frag_v4_compare_key {
42	__be32		saddr;
43	__be32		daddr;
44	u32		user;
45	u32		vif;
46	__be16		id;
47	u16		protocol;
48};
49
50struct 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 */
77struct 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
98struct 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
112int inet_frags_init(struct inet_frags *);
113void inet_frags_fini(struct inet_frags *);
114
115int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);
116
117static inline void fqdir_pre_exit(struct fqdir *fqdir)
118{
119	/* Prevent creation of new frags.
120	 * Pairs with READ_ONCE() in inet_frag_find().
121	 */
122	WRITE_ONCE(fqdir->high_thresh, 0);
123
124	/* Pairs with READ_ONCE() in inet_frag_kill(), ip_expire()
125	 * and ip6frag_expire_frag_queue().
126	 */
127	WRITE_ONCE(fqdir->dead, true);
128}
129void fqdir_exit(struct fqdir *fqdir);
130
131void inet_frag_kill(struct inet_frag_queue *q);
132void inet_frag_destroy(struct inet_frag_queue *q);
133struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key);
134
135/* Free all skbs in the queue; return the sum of their truesizes. */
136unsigned int inet_frag_rbtree_purge(struct rb_root *root);
137
138static inline void inet_frag_put(struct inet_frag_queue *q)
139{
140	if (refcount_dec_and_test(&q->refcnt))
141		inet_frag_destroy(q);
142}
143
144/* Memory Tracking Functions. */
145
146static inline long frag_mem_limit(const struct fqdir *fqdir)
147{
148	return atomic_long_read(&fqdir->mem);
149}
150
151static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
152{
153	atomic_long_sub(val, &fqdir->mem);
154}
155
156static inline void add_frag_mem_limit(struct fqdir *fqdir, long val)
157{
158	atomic_long_add(val, &fqdir->mem);
159}
160
161/* RFC 3168 support :
162 * We want to check ECN values of all fragments, do detect invalid combinations.
163 * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
164 */
165#define	IPFRAG_ECN_NOT_ECT	0x01 /* one frag had ECN_NOT_ECT */
166#define	IPFRAG_ECN_ECT_1	0x02 /* one frag had ECN_ECT_1 */
167#define	IPFRAG_ECN_ECT_0	0x04 /* one frag had ECN_ECT_0 */
168#define	IPFRAG_ECN_CE		0x08 /* one frag had ECN_CE */
169
170extern const u8 ip_frag_ecn_table[16];
171
172/* Return values of inet_frag_queue_insert() */
173#define IPFRAG_OK	0
174#define IPFRAG_DUP	1
175#define IPFRAG_OVERLAP	2
176int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
177			   int offset, int end);
178void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
179			      struct sk_buff *parent);
180void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
181			    void *reasm_data, bool try_coalesce);
182struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
183
184#endif
185