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 
7 struct netns_frags {
8 	/* sysctls */
9 	long			high_thresh;
10 	long			low_thresh;
11 	int			timeout;
12 	int			max_dist;
13 	struct inet_frags	*f;
14 
15 	struct rhashtable       rhashtable ____cacheline_aligned_in_smp;
16 
17 	/* Keep atomic mem on separate cachelines in structs that include it */
18 	atomic_long_t		mem ____cacheline_aligned_in_smp;
19 };
20 
21 /**
22  * fragment queue flags
23  *
24  * @INET_FRAG_FIRST_IN: first fragment has arrived
25  * @INET_FRAG_LAST_IN: final fragment has arrived
26  * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
27  */
28 enum {
29 	INET_FRAG_FIRST_IN	= BIT(0),
30 	INET_FRAG_LAST_IN	= BIT(1),
31 	INET_FRAG_COMPLETE	= BIT(2),
32 };
33 
34 struct frag_v4_compare_key {
35 	__be32		saddr;
36 	__be32		daddr;
37 	u32		user;
38 	u32		vif;
39 	__be16		id;
40 	u16		protocol;
41 };
42 
43 struct frag_v6_compare_key {
44 	struct in6_addr	saddr;
45 	struct in6_addr	daddr;
46 	u32		user;
47 	__be32		id;
48 	u32		iif;
49 };
50 
51 /**
52  * struct inet_frag_queue - fragment queue
53  *
54  * @node: rhash node
55  * @key: keys identifying this frag.
56  * @timer: queue expiration timer
57  * @lock: spinlock protecting this frag
58  * @refcnt: reference count of the queue
59  * @fragments: received fragments head
60  * @rb_fragments: received fragments rb-tree root
61  * @fragments_tail: received fragments tail
62  * @last_run_head: the head of the last "run". see ip_fragment.c
63  * @stamp: timestamp of the last received fragment
64  * @len: total length of the original datagram
65  * @meat: length of received fragments so far
66  * @flags: fragment queue flags
67  * @max_size: maximum received fragment size
68  * @net: namespace that this frag belongs to
69  * @rcu: rcu head for freeing deferall
70  */
71 struct inet_frag_queue {
72 	struct rhash_head	node;
73 	union {
74 		struct frag_v4_compare_key v4;
75 		struct frag_v6_compare_key v6;
76 	} key;
77 	struct timer_list	timer;
78 	spinlock_t		lock;
79 	refcount_t		refcnt;
80 	struct sk_buff		*fragments;  /* used in 6lopwpan IPv6. */
81 	struct rb_root		rb_fragments; /* Used in IPv4/IPv6. */
82 	struct sk_buff		*fragments_tail;
83 	struct sk_buff		*last_run_head;
84 	ktime_t			stamp;
85 	int			len;
86 	int			meat;
87 	__u8			flags;
88 	u16			max_size;
89 	struct netns_frags      *net;
90 	struct rcu_head		rcu;
91 };
92 
93 struct inet_frags {
94 	unsigned int		qsize;
95 
96 	void			(*constructor)(struct inet_frag_queue *q,
97 					       const void *arg);
98 	void			(*destructor)(struct inet_frag_queue *);
99 	void			(*frag_expire)(struct timer_list *t);
100 	struct kmem_cache	*frags_cachep;
101 	const char		*frags_cache_name;
102 	struct rhashtable_params rhash_params;
103 };
104 
105 int inet_frags_init(struct inet_frags *);
106 void inet_frags_fini(struct inet_frags *);
107 
inet_frags_init_net(struct netns_frags * nf)108 static inline int inet_frags_init_net(struct netns_frags *nf)
109 {
110 	atomic_long_set(&nf->mem, 0);
111 	return rhashtable_init(&nf->rhashtable, &nf->f->rhash_params);
112 }
113 void inet_frags_exit_net(struct netns_frags *nf);
114 
115 void inet_frag_kill(struct inet_frag_queue *q);
116 void inet_frag_destroy(struct inet_frag_queue *q);
117 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, void *key);
118 
119 /* Free all skbs in the queue; return the sum of their truesizes. */
120 unsigned int inet_frag_rbtree_purge(struct rb_root *root);
121 
inet_frag_put(struct inet_frag_queue * q)122 static inline void inet_frag_put(struct inet_frag_queue *q)
123 {
124 	if (refcount_dec_and_test(&q->refcnt))
125 		inet_frag_destroy(q);
126 }
127 
128 /* Memory Tracking Functions. */
129 
frag_mem_limit(const struct netns_frags * nf)130 static inline long frag_mem_limit(const struct netns_frags *nf)
131 {
132 	return atomic_long_read(&nf->mem);
133 }
134 
sub_frag_mem_limit(struct netns_frags * nf,long val)135 static inline void sub_frag_mem_limit(struct netns_frags *nf, long val)
136 {
137 	atomic_long_sub(val, &nf->mem);
138 }
139 
add_frag_mem_limit(struct netns_frags * nf,long val)140 static inline void add_frag_mem_limit(struct netns_frags *nf, long val)
141 {
142 	atomic_long_add(val, &nf->mem);
143 }
144 
145 /* RFC 3168 support :
146  * We want to check ECN values of all fragments, do detect invalid combinations.
147  * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
148  */
149 #define	IPFRAG_ECN_NOT_ECT	0x01 /* one frag had ECN_NOT_ECT */
150 #define	IPFRAG_ECN_ECT_1	0x02 /* one frag had ECN_ECT_1 */
151 #define	IPFRAG_ECN_ECT_0	0x04 /* one frag had ECN_ECT_0 */
152 #define	IPFRAG_ECN_CE		0x08 /* one frag had ECN_CE */
153 
154 extern const u8 ip_frag_ecn_table[16];
155 
156 /* Return values of inet_frag_queue_insert() */
157 #define IPFRAG_OK	0
158 #define IPFRAG_DUP	1
159 #define IPFRAG_OVERLAP	2
160 int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb,
161 			   int offset, int end);
162 void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb,
163 			      struct sk_buff *parent);
164 void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
165 			    void *reasm_data);
166 struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q);
167 
168 #endif
169