1 #ifndef __NET_FRAG_H__ 2 #define __NET_FRAG_H__ 3 4 struct netns_frags { 5 /* Keep atomic mem on separate cachelines in structs that include it */ 6 atomic_t mem ____cacheline_aligned_in_smp; 7 /* sysctls */ 8 int timeout; 9 int high_thresh; 10 int low_thresh; 11 int max_dist; 12 }; 13 14 /** 15 * fragment queue flags 16 * 17 * @INET_FRAG_FIRST_IN: first fragment has arrived 18 * @INET_FRAG_LAST_IN: final fragment has arrived 19 * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction 20 */ 21 enum { 22 INET_FRAG_FIRST_IN = BIT(0), 23 INET_FRAG_LAST_IN = BIT(1), 24 INET_FRAG_COMPLETE = BIT(2), 25 }; 26 27 /** 28 * struct inet_frag_queue - fragment queue 29 * 30 * @lock: spinlock protecting the queue 31 * @timer: queue expiration timer 32 * @list: hash bucket list 33 * @refcnt: reference count of the queue 34 * @fragments: received fragments head 35 * @fragments_tail: received fragments tail 36 * @stamp: timestamp of the last received fragment 37 * @len: total length of the original datagram 38 * @meat: length of received fragments so far 39 * @flags: fragment queue flags 40 * @max_size: maximum received fragment size 41 * @net: namespace that this frag belongs to 42 * @list_evictor: list of queues to forcefully evict (e.g. due to low memory) 43 */ 44 struct inet_frag_queue { 45 spinlock_t lock; 46 struct timer_list timer; 47 struct hlist_node list; 48 refcount_t refcnt; 49 struct sk_buff *fragments; 50 struct sk_buff *fragments_tail; 51 ktime_t stamp; 52 int len; 53 int meat; 54 __u8 flags; 55 u16 max_size; 56 struct netns_frags *net; 57 struct hlist_node list_evictor; 58 }; 59 60 #define INETFRAGS_HASHSZ 1024 61 62 /* averaged: 63 * max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ / 64 * rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or 65 * struct frag_queue)) 66 */ 67 #define INETFRAGS_MAXDEPTH 128 68 69 struct inet_frag_bucket { 70 struct hlist_head chain; 71 spinlock_t chain_lock; 72 }; 73 74 struct inet_frags { 75 struct inet_frag_bucket hash[INETFRAGS_HASHSZ]; 76 77 struct work_struct frags_work; 78 unsigned int next_bucket; 79 unsigned long last_rebuild_jiffies; 80 bool rebuild; 81 82 /* The first call to hashfn is responsible to initialize 83 * rnd. This is best done with net_get_random_once. 84 * 85 * rnd_seqlock is used to let hash insertion detect 86 * when it needs to re-lookup the hash chain to use. 87 */ 88 u32 rnd; 89 seqlock_t rnd_seqlock; 90 unsigned int qsize; 91 92 unsigned int (*hashfn)(const struct inet_frag_queue *); 93 bool (*match)(const struct inet_frag_queue *q, 94 const void *arg); 95 void (*constructor)(struct inet_frag_queue *q, 96 const void *arg); 97 void (*destructor)(struct inet_frag_queue *); 98 void (*frag_expire)(unsigned long data); 99 struct kmem_cache *frags_cachep; 100 const char *frags_cache_name; 101 }; 102 103 int inet_frags_init(struct inet_frags *); 104 void inet_frags_fini(struct inet_frags *); 105 106 static inline void inet_frags_init_net(struct netns_frags *nf) 107 { 108 atomic_set(&nf->mem, 0); 109 } 110 void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f); 111 112 void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f); 113 void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f); 114 struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, 115 struct inet_frags *f, void *key, unsigned int hash); 116 117 void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q, 118 const char *prefix); 119 120 static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f) 121 { 122 if (refcount_dec_and_test(&q->refcnt)) 123 inet_frag_destroy(q, f); 124 } 125 126 static inline bool inet_frag_evicting(struct inet_frag_queue *q) 127 { 128 return !hlist_unhashed(&q->list_evictor); 129 } 130 131 /* Memory Tracking Functions. */ 132 133 static inline int frag_mem_limit(struct netns_frags *nf) 134 { 135 return atomic_read(&nf->mem); 136 } 137 138 static inline void sub_frag_mem_limit(struct netns_frags *nf, int i) 139 { 140 atomic_sub(i, &nf->mem); 141 } 142 143 static inline void add_frag_mem_limit(struct netns_frags *nf, int i) 144 { 145 atomic_add(i, &nf->mem); 146 } 147 148 static inline int sum_frag_mem_limit(struct netns_frags *nf) 149 { 150 return atomic_read(&nf->mem); 151 } 152 153 /* RFC 3168 support : 154 * We want to check ECN values of all fragments, do detect invalid combinations. 155 * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value. 156 */ 157 #define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */ 158 #define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */ 159 #define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */ 160 #define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */ 161 162 extern const u8 ip_frag_ecn_table[16]; 163 164 #endif 165