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