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 */
13struct 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 */
40enum {
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
48struct frag_v4_compare_key {
49	__be32		saddr;
50	__be32		daddr;
51	u32		user;
52	u32		vif;
53	__be16		id;
54	u16		protocol;
55};
56
57struct 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 * @mono_delivery_time: 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 */
85struct 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			mono_delivery_time;
101	__u8			flags;
102	u16			max_size;
103	struct fqdir		*fqdir;
104	struct rcu_head		rcu;
105};
106
107struct 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
121int inet_frags_init(struct inet_frags *);
122void inet_frags_fini(struct inet_frags *);
123
124int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);
125
126static 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}
138void fqdir_exit(struct fqdir *fqdir);
139
140void inet_frag_kill(struct inet_frag_queue *q);
141void inet_frag_destroy(struct inet_frag_queue *q);
142struct 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. */
145unsigned int inet_frag_rbtree_purge(struct rb_root *root,
146				    enum skb_drop_reason reason);
147
148static 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
156static inline long frag_mem_limit(const struct fqdir *fqdir)
157{
158	return atomic_long_read(&fqdir->mem);
159}
160
161static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val)
162{
163	atomic_long_sub(val, &fqdir->mem);
164}
165
166static 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
180extern 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
186int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
187			   int offset, int end);
188void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
189			      struct sk_buff *parent);
190void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
191			    void *reasm_data, bool try_coalesce);
192struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
193
194#endif
195