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.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 195