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 */ 9 struct 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 struct llist_node free_list; 25 }; 26 27 /** 28 * fragment queue flags 29 * 30 * @INET_FRAG_FIRST_IN: first fragment has arrived 31 * @INET_FRAG_LAST_IN: final fragment has arrived 32 * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction 33 * @INET_FRAG_HASH_DEAD: inet_frag_kill() has not removed fq from rhashtable 34 */ 35 enum { 36 INET_FRAG_FIRST_IN = BIT(0), 37 INET_FRAG_LAST_IN = BIT(1), 38 INET_FRAG_COMPLETE = BIT(2), 39 INET_FRAG_HASH_DEAD = BIT(3), 40 }; 41 42 struct frag_v4_compare_key { 43 __be32 saddr; 44 __be32 daddr; 45 u32 user; 46 u32 vif; 47 __be16 id; 48 u16 protocol; 49 }; 50 51 struct frag_v6_compare_key { 52 struct in6_addr saddr; 53 struct in6_addr daddr; 54 u32 user; 55 __be32 id; 56 u32 iif; 57 }; 58 59 /** 60 * struct inet_frag_queue - fragment queue 61 * 62 * @node: rhash node 63 * @key: keys identifying this frag. 64 * @timer: queue expiration timer 65 * @lock: spinlock protecting this frag 66 * @refcnt: reference count of the queue 67 * @rb_fragments: received fragments rb-tree root 68 * @fragments_tail: received fragments tail 69 * @last_run_head: the head of the last "run". see ip_fragment.c 70 * @stamp: timestamp of the last received fragment 71 * @len: total length of the original datagram 72 * @meat: length of received fragments so far 73 * @flags: fragment queue flags 74 * @max_size: maximum received fragment size 75 * @fqdir: pointer to struct fqdir 76 * @rcu: rcu head for freeing deferall 77 */ 78 struct inet_frag_queue { 79 struct rhash_head node; 80 union { 81 struct frag_v4_compare_key v4; 82 struct frag_v6_compare_key v6; 83 } key; 84 struct timer_list timer; 85 spinlock_t lock; 86 refcount_t refcnt; 87 struct rb_root rb_fragments; 88 struct sk_buff *fragments_tail; 89 struct sk_buff *last_run_head; 90 ktime_t stamp; 91 int len; 92 int meat; 93 __u8 flags; 94 u16 max_size; 95 struct fqdir *fqdir; 96 struct rcu_head rcu; 97 }; 98 99 struct inet_frags { 100 unsigned int qsize; 101 102 void (*constructor)(struct inet_frag_queue *q, 103 const void *arg); 104 void (*destructor)(struct inet_frag_queue *); 105 void (*frag_expire)(struct timer_list *t); 106 struct kmem_cache *frags_cachep; 107 const char *frags_cache_name; 108 struct rhashtable_params rhash_params; 109 refcount_t refcnt; 110 struct completion completion; 111 }; 112 113 int inet_frags_init(struct inet_frags *); 114 void inet_frags_fini(struct inet_frags *); 115 116 int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net); 117 118 static inline void fqdir_pre_exit(struct fqdir *fqdir) 119 { 120 /* Prevent creation of new frags. 121 * Pairs with READ_ONCE() in inet_frag_find(). 122 */ 123 WRITE_ONCE(fqdir->high_thresh, 0); 124 125 /* Pairs with READ_ONCE() in inet_frag_kill(), ip_expire() 126 * and ip6frag_expire_frag_queue(). 127 */ 128 WRITE_ONCE(fqdir->dead, true); 129 } 130 void fqdir_exit(struct fqdir *fqdir); 131 132 void inet_frag_kill(struct inet_frag_queue *q); 133 void inet_frag_destroy(struct inet_frag_queue *q); 134 struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key); 135 136 /* Free all skbs in the queue; return the sum of their truesizes. */ 137 unsigned int inet_frag_rbtree_purge(struct rb_root *root); 138 139 static inline void inet_frag_put(struct inet_frag_queue *q) 140 { 141 if (refcount_dec_and_test(&q->refcnt)) 142 inet_frag_destroy(q); 143 } 144 145 /* Memory Tracking Functions. */ 146 147 static inline long frag_mem_limit(const struct fqdir *fqdir) 148 { 149 return atomic_long_read(&fqdir->mem); 150 } 151 152 static inline void sub_frag_mem_limit(struct fqdir *fqdir, long val) 153 { 154 atomic_long_sub(val, &fqdir->mem); 155 } 156 157 static inline void add_frag_mem_limit(struct fqdir *fqdir, long val) 158 { 159 atomic_long_add(val, &fqdir->mem); 160 } 161 162 /* RFC 3168 support : 163 * We want to check ECN values of all fragments, do detect invalid combinations. 164 * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value. 165 */ 166 #define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */ 167 #define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */ 168 #define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */ 169 #define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */ 170 171 extern const u8 ip_frag_ecn_table[16]; 172 173 /* Return values of inet_frag_queue_insert() */ 174 #define IPFRAG_OK 0 175 #define IPFRAG_DUP 1 176 #define IPFRAG_OVERLAP 2 177 int inet_frag_queue_insert(struct inet_frag_queue *q, struct sk_buff *skb, 178 int offset, int end); 179 void *inet_frag_reasm_prepare(struct inet_frag_queue *q, struct sk_buff *skb, 180 struct sk_buff *parent); 181 void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head, 182 void *reasm_data, bool try_coalesce); 183 struct sk_buff *inet_frag_pull_head(struct inet_frag_queue *q); 184 185 #endif 186